i '2222final report for / fine attitude control system phase i july, 1969 s_ y42r-8 contract...
TRANSCRIPT
-!:-_
-/L_-
I'
F_nalforReport _ •
Fine Attitude Control System- _
Phase I _::i
I" SGC 742R-8_ Contract No. NAS9-9096
._ Volt,meI of II -: _
L
GPO PRICE $t
CFSTI PR!CE(S ) $ ....Prepared byt' E
g.
Space-GeneralCorporation i9200 East Flair Drive Ha_'dcopy (HC) ,v._. 0-O ,. _
E1 Monte, California _ .e53Microfichej._e_ __ (MF) /. _ L) i
for- ,z
Goddard Space Flight CenterGreenbelt, MarYland "-j
2F 4 :.<
' _ " : I (AGGEIIION NUMBER) • .... ' t?NPU) '"
I ,'2222o
1966018034
https://ntrs.nasa.gov/search.jsp?R=19660018034 2020-02-19T21:25:53+00:00Z
Final Report
for /
Fine Attitude Control System
Phase I
July, 1969
s_ y42R-8
Contract No. NAS5-9096
Volume I of II
Prepared by
Space-General Corporation9200 EastFlair Drive
: EiMonte, California
l
L
for
Goddard Space Flight centerGreenbelt, Ma@yland
Approved by
iJenkins
FACS Project Engineer
F__ .Pr'_Manager_. E,me-r,;.:
t"
Director of Engineering
Space Operations
5
• /
1966018034-002
CONTENTS
Pa___ e
SECTION 1 - INTRODUCTION AND SUMMARY ................. !
SECTION 2 - FACS REQUIREMENTS .................... 2
2.1 General ......................... 2
2.2 Operational Requirements ................ 22.3 Phase I Requirements .................. 32.3.1 Basis for IACS Design ................ 32.3.2 IACS Inertial Reference .............. 3
2.3.3 IACS Rate Stabilization .............. 42.3.4 Torquing Devices .................. 4
2.3.5 Despin Control and Initial Capture ....... 42.3.6 Prelaunch Adjustment .............. 5
2.3.7 Maneuver Sequence .... ............ 5f 2.3.8 Transfer to SACS Operation .... •......... 5
2.3.9 FACS Packaging Design ................ 62.3.10 AC Power Supply ................. 6
2.3.11 DC Power Supply .............. 6J,
SECTION 3 - FACS DESCRII_gION ...................... 7
3.1 Configuration and Operation .............. 73.1.1 FACS Sequence of Operation • .......... ll3 1 2 Gyro Caging Interfac _ 17• • . • • • • • • • • • • • • • • • •
3.1.3 Control Parameters ................ 173 2 Breadboard FACS _ 2!. • • * • • 4 • • * • • • * • • • • • •
3.3 Braadboard GSE ...................... 213 •4 FACS Subassemblies ................... 513.4,1 Static Inverter ................... 313.4.2 DC Power Supply • • • ................ 313.4.3 Programmer ..................... 333.4.4 IACS Control Electronics • • ,........... 353.4.5 SACS Control Electronics .............. 373.4.6 Telemetry Signal Conditioner ............ 373.4.7 _ Junction Box .................... 373.4.8 Roll Stabilized Platform . .......... • 443 4 9 Rate Gyros ;3 5 _ Sensor ' _)t-
4'7
SECTION 4 - FACS PKASE I PROGRAM ................ 48
°4 1 Work Statement Items 48
4 2 Design _ 49
Page iiA
i
3-
1966018034-003
CONTENTS (_Continued)
Page
4.3 Analysis ......................... 50
4.3.1 Pneumatics Analysis .............. 504,3.2 Analog Computer Study ......... ....... 504-3.5 Roll Slaving Analysis ............... 554.4 Bench Test ........................ 55
4.4.1 Subassembly and Module Tests ............ 584.4.2 Systen: Test and Calibration ............ 584.4.5 V_T Test .................. 594.5 Three-Ax'.s Simulator Test ................ 604.5.1 Test Description ................ 604.5.2 Maneuver Evaluation ............... 67
4.5.3 Acquisition EvalL_ation .............. 774.5.4 Limi-_ Cycle Evaluation ............... 894.5.5 Configuration Comparison ..... • ...... 98
4.5.6 Final Configuratio n Summary ............ 99 :4-5.7 Correlation With Analog Computer Studies ...... i00
4.5.8 Delayed Feedback - Preliminary Investigation . • • I°_3
SECTION 5 - SYSTEM CHANGES (PHASE II ................ 127
5.1 Oplional Features - Selection of Alternate ........ 1275.2 Design Changes ........ .............. 127
SECTION 6 - CONCLUSIONS AND RECOMME_U)ATIONS ........... - • 130
APPENDIX I - FUNCTIONAL DESCRIPTIONS AND SCHEMATICSAPPENDIX II - BREADBOARD FACS PARTS LISTAPPENDIX III - PNEUMATIC ANALYSIS OF AEROBEE ACS FORCE CONTROL SYSTEMAPPENDIX IV - BREADBOARD FACS SUBASSEMBLY AND MODULE TEST DATAAPPENDIX V - FACS SYSTEM TEST AND CALIBRATION DATAAPPENDIX VI - BREADBOARD FACS TELEMETRY SIGNAL-CONDITIONER CALIBRATIONAPPENDIX VII - OPEP_TIONAL PROCEDURES AND PARAMETER CHANGESAPPENDIX VIII- FACS TECHNICAL NOTE RE-EVALUATION OF RAMP MANEUVER CHARACTERISTICSAPPENDIX IX - EXPLANATION OF THE DEFERMENT OF ROLL SLAVING UNTIL COMPLETION OF
ATTITUDE CAPTURE
APPENDIX X - •CORRECTION OF TP_ EFFECT OF INNER GIMBAL ANGLE ON TORQUING RATEz
Ji
J
, _ Page iii
1966018034-004
-¢._,
?
ILLUSTRATI ONS _I
Figure Pag___e I
i Fine Attitude Control System, S_mpli±ied Block Diagram .... 8 i
2 FACS Pitch and Yaw, Block Diagram .............. 9
3 FACS Roll and Slave Roll, Block Diagram ........ • • • i0 il
4 FACS Pitch and Yaw, Control Block Diagram .......... 18 F_I_I
FACS Roll and Slave Roll, Control Block Diagram ....... 19
6 FACS Body Axis Definition .................. 20
7 Breadboard FACS, View No. i ................. 24 _!
8 Breadboard FACS, View No. 2 2_
9 Breadboard FACS, View No. 3 ................. 26 _'
i0 Breadboard FACS, View No. 4 ...... _......... 27
ll Breadboard GSE, Front View ................. 28
12 Breadboard GSE, Panel .................... 2913 Breadboard GSE, Inside View ................. 30
14 Breadboard Static Inverter Subassembly ............ 32
i_ Breadboard DC Power Supply Subassembly ............ 34
16 Breadboard Programmer Subassembly, Front View ....... 39
17 Breadboard Programmer Subassembly, Rear View ........ _6
18 Breadboard IACS Control Electronics Subassembly, Front View • 38
1"9 Breadboard IACS Control Electronics Subassembly, Rear View • . 39
20 _ Breadboard SACS Control Electronics Subassembly, Front View 40 Q
21 Breadboard SACS Control Electronics Subassembly, Rear View • • 41
22 Breadboard Telemetry Conditioning Subassembly, Front View • 42
23 Breadboard Telemetry Conditioning Subassembly, Rear View • . • _3 _
2_ Roll Stabilized Platform Subassembly . . • .......... 4_
29 Rate Gyro Subassembly 46
26 _ACS Posit; _n Signal IJimiterChange, Servo B_oc_ Diagram . • • _2
27 IACS Position signal Limiter Change, Analog Computer _Circuit ............. _ ........... _3
Page _v
.j
1966018034-005
ILLUSTR&TIONS (Continued)
Figure
28 Maneuver Torquing Change, Servo Block Diagram ........ 56
29 Maneuver Torquing Change, Servo Block Diagram ........ 57
_0 G_FC Three-Axis Simulator Facility ............ 61
31 Position Channel "Soft Limiting" Characteristic ....... 68
32 FACS Maneuver Characteristics for Acceleration = 1.4 deg/sec 2
(Three-Axis Simulator Run 47) ........... 70
33 FACS Maneuver Characteristics for Acceleration = 1.4 deg/sec 2(Three-Axis Simulato _ Run 47 Continued) .......... 71
3_• FACS Maneuver Characteristics for Acceleration = 1.9 deg/sec 2
(Three-Axis Simulator Run 48) .............. 72
35 FACS Maneuver Characteristics for Acceleration = 3.0 deg/sec 2(Three-Axis Simulator Run 49) ................ 73
36 FACS Maneuver Characteristics for Acceleration = 3.6 deg/sec 2(Three-Axis Simulator Run 51) ............... 74
37 FACS Maneuver Characteristics for Acceleration = 3.6 deg/sec 2
(Three-Axis _Simulator Run 51 Continued )........... 75
38 Comparison - Rate Gyro Performance at 0.2 deg/sec ..... 79
39 Comparison - Rate Gyro Performance at O.1 deg/sec ...... 80
40 FACS Acquisition Characteristics for G = 1.9 deg/sec 2(Three-Axis Simulator Run 40) . c 85
41. FACS Acquisition Characteristics for G = 3.0 deg/sec 2
(Three Axis Simulator Run 49) c 86m • • • • • • • • • • • • • •
42 FACS Acquisition Characteristics for ac = 3.6 deg/sec 2(Three-Axis Simulator Run 50) ............... 87
43 FACS Acquisition Characteristics for Reduced GF(Three-Axis Simulator Run 52) . . . ........... 88
44 • SACS Limit Cycle- Correlation of Sensor to Autocollimator . . 92
)'5 SACS Limit Cycle Characteristics for Switch_ng Threshold+22.5 Arc Seconds .................... 94 ,
_6 SACS Limit C_jcle Characteristics for Switching Thz'eshold+lO Arc Seconds ........................ 95
47 SACS Limit Cycle Characteristics for Switching Threshold+5 Arc Seconds ....................... 96
Page v
1966018034-006
, j _,
L
ILLUSTRATIONS (Continued)
t?
Figure P.._ag_._e
48 75° Maneuver at (z = 1.4 deg/sec 2 (Analog Run 21M) ...... lO1C
• 1 ,'749 75 ° Maneuver at a c = 3 6 deg/sec 2 (Ana._o6 Run 24M) ...... 102
50 20o Maneuver at a c = 1.4 deg/sec 2 (/h_log Run lOM) ...... 103
51 20° Maneuver at (_c = 3.6 deg/sec 2 (Analog Bun 7M) ....... 104
52 IACS Switching Logic Derived from Pos_tio_.-Limiter
Calibration (K_'/K] = 1.55 sec) ............... 108 i
53 Comparison Between Analog and 3-Axis Simulaticn Switch I
Points (75° Maneuver) ................... ii0
54 Acquisition and Limit Cycle for SEO = 0f (Analog Run 21A-i ) ..................... 116
_ 55 Acquisition and Limit Cycle for _EO = + 3o _
(Analog Run 21A-2 ) ..................... 117 i56 Acquisition and Limit Cycle for _E = - 30(Analog R'_u21A-3 ) • • • 0 118
57 " Acquisition and Limit Cycle.for _EO = 0 119(Analog Run 24A-I) . • •..................
58 Acquisition and Limit Cycle for C_ = 0.06 deg/sec 2(Analog Run llA-1 ) ..................... 120
59 Acquisition and Limit Cycle for eTF = I0 arc sec(Analog Run 25A-1) .................. 121
60 Delayed Feedback in SACS, Block Diagram ........... 124
61 Acquisition and Limit Cycle with Delayed Feedback(Three-Axis Simulator Run 56) ............... 126
Page vi
19660180:34-007
TABLES
Table Page
1 Phase and Polarity Definition - IACS ............ 22
2 Phase and Polarity Definition - SACS ............ 23
3 DFG Settings for Position Signal Limiter Simulation ..... 54
4 Breadboard Face Programmer Sequence for 3-AxisSimulator Test ..................... 62
5 Telemetry Measurements for Three-Axis SimulatorTest of FACS ....................... 64
6 Maneuver Parameters from Three-Axis Simulator Tests ..... 76
'Y Effect of Mixing Ratio on Acquisition ............ _2
8 Effect of Acceleration on Acquisition from Three-AxisSimulator Tests ...................... 84
9 SACS Limit Cycle Characteristics (Without Delayed-Feedback)
• from Three-Axis Simulator Tests ........... • • • 97
lO Index of Selected Runs ................... 109
ll Analog SimulationManeuver Parameters for 75 DegreesYawManeuver ....................... ]06
12 Comparison of Analog and 3-Axis Simulator Maneuver Resultsfor 75 Degree Maneuver .................. _ll
13 Maximum Lag Angle Comparison for 20 Degree Maneuw_f ..... lll
14 Effect of Acceleration on Acquisition, Configuration I • • . ll3
15 Analog Simulation Effect of Mixing Ratio on Acquisition . . . ll4
16 Analog Simulation SACS Limit Cycle Characteristics ..... 122
Page vii
1966018034-008
Section i ,
INTRODUCTION AND SUMMARY
5
Space-General Corporation (SGC) under Contract NAS5-9056 f om the
National Aeronautics add Space Administration_ Goddard Space Flight Center
(NASA-GSFC), has completed Phase i of a program for development of a Fine Atti-
tude Control System (FACS).
The FACS will point the experiment package of an Aerobee i_3 se-
ries rocket a_ the sun or at a series of stellar targets. Utilizing a combina- {
tion of gyro-inertial and optical sensors_ rapid acquisition e::dprecision !
pointing are achieved.
'J' The Phase I program involved design_ fabricat]on_ and test of a
breadboard model of the FACS and of associated ground suppor_ equipment. The _
Iwork was based upon an earlier feasibilit,_ demons+!_t _,_ program carried out by
SGC under Contract NAS5-2666. The breadboa_-d FACS was constructed by integra-tion of individual breadboard subasselnblies into a structure suitaLic for mount-
_._ing on a fl_ght simulator. SubassembJl.<s were individually tested pri->r to in-
corporation into the system. The final demonstration of acceptabi3i_ .,as _
carried out at the 3-axis gas bearing :_ _tor facility ].ocated a_ _ci',_, @:
T'.'_._ breadboard FACS succe_sfully met all requizements, i_ase II _-
of the prog-_.am,to be initiated shortly, w,.±iculminate in flight _.- of the i_
FACS. [;
This document constitutes final fulf-i_l_ent of ,'' ,'cquirements !
under Phase I. !i
A close working relationship between GSFC and o_?_._hss persisted I
throughout this work and the feasibility work under NAS 5-2666. The feasibility-
£
Idemonstration program has been reported in Reference 4. The feasibility model
included the uni-directional ___.:itchoverimplementation proposed by GSFC and de-
scribed in Reference _. i
t,
!I
19660180:34-009
During this FACS Phase I program_ GSFC has provided important
contributions i_,the following areas:
a. 'The fine sun sensor for the FACS is a Goddard designed anddeveloped unit. GSFC conceived the basic idea of a sun s_n-sor whose output characteristic5 would closely match thoseof the long-planned stellar sensor_ thus penitZing theFACS to be used interchangeably a_ a solar pointing or astellar pointing system.
GSFC specified and evaluated the Ball Brothers Fine Eyesand Burr-Brown am_Tifiers_ which are compo-ents of zhesun seusor unii;j designed the electronic circuitry toshape the output signal properly_ packaged the sun sensorcomponents into a breadboard sub-assembly and made an ex-haustive evaluation of the packaged sun sensor. The resultsof this design and development effort were reported in ReZ-erence 6.
b. GSFC initiated and tested a mo4ification of zhe SGC Variable
Time Torquing (VIT) Scheme that utilizes fewer components.This modification, known as the "current-only mode" was latertested by SGC. Good test results _ere obtained by both SGCand GSFC. This mode has been selected for incorporation inPhase II, resulting in a simplification of the VTT circuitry.
c. GSFC proposed, implemented and investigated a lag feedback
scl_me for the FACS which has resulted in a marked improvu-ment in the fine limit cycle performance. This same tech-nique was also applied by GSFC to the I_CS with a correspond-ing improvement in coarse limit cycle performance. GSFChas optimized the lag feedback circuitry for both coarse andfine modes, and has transmitted the results to SGC for in-corporation iu Phase II.
d. GSFC also proposed and established th_ values for the soft-limiting technique in the coarse pitch and yaw channels.This permitted a reduction in rate gain wita a consequentred_.,tion in the valve "hammering" that occurred at highacceleration.
e. GSFC ccnceived, designed and developed a sophisticated 3-a_;.sair bearing facility capable of demonstrating the fine point-ing performance of the FACS. This facilityhas an operatingand measurement resolution of about + 1 arc-second.
1966018034-010
Section 2
FACS REQUIREMENTS
_- 2.1 G_
The Fine Attitude Control System (FACS) has been designed to be
suitable as either a solar pointing r. a stellar pointing FACS for bhe Aerobee
l_O series rockets, initially, the system will be used as a solar pointing
FACS. However. the same system, with minor modifications _nd adjustments (in-
cluding substitution of a fine stellar sensor for the fine solar sensor), will
be suitable as a stellar pointing FACS.
_. The FACS consists of two basic subsystems: an Inertially -
f Referenced Attitude Control System (IACS) that places the rocket longitudinal
axis approximately on target and provides roll control for the entire coasting
portion of flight, and a Solar (or Stellar)-Referenced Attitude Control System ._
(SACS). The SACS senses the pointing errors in pitch and yaw after the IACS
_has stabilized the rocket approximately on target, and takes corrective action
to re_movethese errors. In addition_ the SACS initially corrects the accumu-
lated pitch and yaw errors in the iACS and continually maintains this correc-
tion during the viewing time on the target.
The system design permits use of just the IACS portion of the
system in the normal IACS mode. Five roll-pitch or roll-yaw maneuver capability
is requiredj each maneuvgr ranging from i0° to 75° per axis.
_2.2 OFERATIONAL REQUIREMENTS
<The Aer<;bee rocket flies as a spinning_ aerodynsmica!/.V-sgabilized
Vehicle through the powered portion of flight.- After burnout of [.heAerobee 150t
rocket, the IACS maneuvers and stabilizes the rocket in three axes so that the
vehicle longitudinal axis is pointed at the desired target within 2 An each
,axis. At this time the '_ehicleis oscillating in each axis in _ i.imit cycle
• that is approximately + 0.2_ ° in amplitude. The SACS thereafter takes over
2
i
1966018034-011
'°_ •control in pitch and yaw to accomplish two lunc_!_ns First is the correction
of the pitch and yaw reference errors in the IACS. The second is the control
of the rocket in pitch and yaw in such s way that the rocket is stabilized
within J 28 arc sec of the reference established by the solar (or stellar) sen-
sor; i.e., each axis is stabilized within +20 arc sec (28 arc sec/v"I3. Fine
jets are used in the SACS to accomplish this fine stabilization. It is desired
that fine stabilization occur within i0 sec after the IACS has stabilized the
rocket approximately on target. The IACS continues to maintain roll control
a_d stabilization during the entire coasting flight. The IACS roll limit cycle
amplitudes and frequencies are acceptable if they do not affect the fine stabi-
lization performance requirements in pitch and yaw.
During the viewing time on target_ the &%CS continually nulls out
the reference errors in the IACS by caging the pitch and yaw gyros to the ref-
erence established by the fine sensor. In the stellar pointing FACS, control
is switched back to the IACS at a pre-programmed time. The rocket is maneuvered
to new coordinates near another stellar target_ at which time the previously
described sequence is repeated.
2.3 PHASE i REQUIREMENTS
The objective of the Phase I program was to provide an FACS design
meeting the above basic requirements. Additional specific features of system
design were specified as follows.
2.3.1 BASIS FOR IACS DESIGN
The IACS portion of the FACS shall be based in general on the
configuration develope9 under contract NAS 5-299 together with certain m_ific_-
tions incorporated in IACS Serial No. 17.
2.3.2 IACS INERrlAL REFEP_NCE
The inertial reference in the IACS shall consist of a roll stabi-
lized platform containing two 2-degree-of-freedom gyros. The gyros are to be
mounted such that their spin axes are nominally horizontal and orthogonal to
3
1966018034-012
one another, with the outer gimbal of each gyro serving as an inertial roll
reference. The roll synchro output of one gyro shall serve as the error detec-
_u¢ in a servo drive Lba_ stabilizes the platform in roll for Aerobee 130 spin
rates up to 3.0 rps. A platform synchro, similar to the gyro synchro_ shall
ser#e as the roll error detector for the IACS after despJn. It is also permis-
sible to mix the platform synchro output with the roll gyro output to form the
roll error signal. The inner gimbal of one gyro shall serve as the inertial
reference in pitch while that of the other gyro provides the yaw reference for
the i_sitional orientation of the rocket after despin.
2.3.3 IACSRATE STABILIZATION
The positional control loop in each axis shall utilize fixed rate
feedback from a rate gyro for stabilizatJoh purposes. A single value of rate
gain feedback per axis shall be used for all maneuvers. The value of rate feed-
back shall be such as to provide critical or over-damped orientation for roll
step maneuvers up to 180 ° after despin and for ramp manauvers up to 75° in each
axis through the remainder of coasting flight. After roll despin and capture_
a one-time change in rate gain feedback in roll only is desired to optimize ramp
maneuvers up to 75 ° . A design goal should be the use of a single fixed level
of rate feedback in each of the pitch and yaw axes_ if at all compatible with
reasonable IACS limit cycle o_aration as well as FACS operation.
2.5.4 TORQUING DEVICES
The torquing devi:es in each axis shall be on-off jets operating
from the residual helium in the rocket tanks after powered flight and despin.
The selected single value of rate feedback in each axis for critlcal or over-
damped orientation shall take into account the expected variation in jet thrust
during coasting flight as the tank pressu_ drops, as well as the variation in
vehicle inertia from one payload to another.
2.3.5 DESPiN CONTROL AND INITIAL CAPTURE
Despin control shall use rate information from the roll rate gyro
to bring the rocket spin rate to near zero after powered flight. At this point,
4 i'_.
t
1966018034-013
oll capture shall be performed by means of the positiunal control system fol-
lowed by vehicle pitch and yaw stabilization to the initial gyro settings.
2.3.6 PRELAUNCH ADJUSTMENT
The initial inertial reference settings of the position gyros in
pitch, yaw, and roll shall be performed on the ground prior to launch by appro-
priate precision torquing and monitoring o_ the spin axis of each gyro. These
offset angles shall be limited to 20° maximum in each axis, and shall be accu-
rate to within _ i/4° of the desired values. The breadboard system design and
associated groun@ equipment shall contain provision for offset caging of the
gyros via three-wire gyro synchros in addition to offset caging via two-wire
gyro s_unchros.
2.3.7 MANEUVER SEQUENCE
After stabilization to initial coordinates, subsequent maneuvers
are to be performed as follows. The roll g_o is to be torqued to the pre-
determined angle with the vehicle following in roll during this time. Pitch
and yaw gyro torquing and pitch and yaw maneuver are to be disarmed unt i1 both
the roll torquing is complete and the vehicle has stabilized in roll within some
small angle. At this point, pitch _iro torquing and pitch maneuver are to be -_
activated. At the completion of the pitch maneuver, yaw gyro torquing and yaw
maneuver are to be activated, enabling the IACS to complete the vehicle maneuver.
The torquing angles shall be accurate to within 1% of the desired values or
within 1/4°, whichever is greater, for all inverter frequency and voltage v_ria-
tions and for a range of temperature from 32°F to 140°F.
2.3.8 TRANSFER TO SACS 0PEPATION
When the IACS has stabilizel the vehicle approximately on target,
with an oscillation of + 0.3 ° or less for about one second, the pitch and yaw
gyros are to be caged to the fine solar (or stellar) sensor, The output error
voltage of each gyro will very quickly rise to a level determined by the fine
sensor error voltage. The remainder of the IACS remains in operation so that
5
1966018034-014
the IACS jets torque the rocket to a new position that will minimize these gyro
_rror voltages. When each gyrc error voltage again decreases to a level cor-
responding to Z 0.3° or less, for about i second_ that axis can independently
switch over completely to fine jet stabilization, using the appropriate axis
error information of the fine sensor. The caging of the pitch and ya_ gyros to
the f_ue _nsor is to remain locked-in during the entire viewing ti_e on target.
If, i_ a_lyreason, the attitude error of the vehicle in any axis increases to
a point where the caged gyro output voltage exceeds that corresporJing to + 0.3 °
vehicle stabilization in the axis shall revert to the coarse jets of the IACS.
Pe-transfer to the fine jets shall take place as described _reviously. In the
case of t_e stellar pointing FACS_ the subsequent pre-progra_r_ed maneuver will
remove the lock-in of the gyro caging and cause appropriate torquing _f the gyro
axes and vehicle stabilization to the new target via the IACS. Transfer to the
SACS will occur as previously described.
A design goal should be the use of a single level detector in
each of +he pitch and yaw axes to serve as both the SACS-enable level detector
(0.3° nominal) and as a detector indicating completion of IACS-controlled
maneuvers.
2.3.9 FACS PACKAGING DESIGN
The design shall be based on a modular concept of distinct, read-
ily interchangeable components and subassemblies.
2.3.10 AC POWER SUPPLY
A single_ sine-wave inverter shall supply the two-phase, 26-volt,
400-cycle requirements for the FACS. The inverter shall have s frequency regu-
• lation of _ 0.2% and a voltage regulation of _ 2% for input voltages from 24 to
34 VDC, output load variations from 25% load to full load, and temperature
variations from 32°F to 140°F.
2.3.1] DC POWER SUPPLY
A single regulated DC power supply, fed solely from the inverter, _i-
shall supply all the regulated DC voltages required in the FACS. _!_
1966018034-015
Section 3
FACS DESCRIPTION
3.1 CONFIGURATION AND OPERATION
A simplified block diagram t_ the FACS is shown in Figure i. It
shows the desigpation of IACS and SACS used herein to identify the two basic
FACS subsyste__s.
The L_.CS is a self-contained control system_ capable of t_e by
itself or in conjunction with the SACS subsystem. The major assemblies of the
IACS are: roll-stabilized platform incorporating two free gyros, rate gyro
package, static incerter, DC power supply, programmer, IACS control unit, and
reaction jet pneumatlc circuits.
The SACS provides the auxiliary control channels needed for pitch
and yaw fine-pointing control using line-of-sight error signals f_-um a stellar
(or solar) sensor. The SACS consists of sep_.or_ derived-rate networks, logic
circuitry for changeover from IACS to SACS operation, reaction jet control elec-
tronics, and lOw-thrust jet pneumatic circuits. All power requirements are pro-
vided by the IACS. The IACS programmer provides an initiation signal for SACS
operation when a target-seeking maneuver is completed.
More detailed block diagrams are shown in Figure 2 (pitch and yaw)
and in Figure 3 (roll and slaved roll). The following description covers all of
the logic and timing functions shown in these diagrams. Several optional pro-
visions are included. These optional features were incorporated in the bread-
board FACS for subsequent evaluation. A selection of the preferred configuration
was then made during tests on the 3-axis shnulator. Appendix VIi describes the
method of implementation for each of the optional features. This appendix also
covers operating procedures for the breadboard FACS and its associated GSE.
7
1966018034-016
IIIII!
8
1966018034-017
fi
........... i ...........
L:::J--:_
,... ......... :_oc_) I 1
r ,_o,,.-. L___VALVE -..-----_,.) I I _d.....ARM i j
J I F---
_A/.:/,.A,v6ej o_2 / _ , 3
r'/
t i_TO._(_I.IIN,":
3T_'7"
I_51T/ON
-- -- MOIIII/-_,ePOS/T/ON TEL EME'I'.eY
(5)
PROGRAMMER
q _ I " •
1966018034-018
/9
p :- --
tLoc_
, P/7"C/*/ _ Y/_O "
........................... I ...............RSP
I I
r- 't"--m
k ' I ...._-]]JT\]-J] ]]: \-JJJ]- - 70JZOU_ 1 _ /-0 REL,_Y [ I
_2 '_-_-_I II I ;__-_'_'_-___,_-_ _ "-_"_-_, _.J_,{.,,,o_ll ;__L-4,111 I ---t- L____ .
----- ,OL.DIN_ I _ ' ".............................. '
, , : \F-- ............ J !: ...........
I I I_ Io (11)- - ___ il __, I I 5AC5 co_7"_0/,u/¢/rL .... _ l i I <'" _"_"_°> I I "'"
i YA 141 _ Y,_O
i _ __-- [
Figure 2. FACS Pitch and Yaw_ Block Diagram
1
1966018034-019
,,VC_- , "fII_F/YT"A_FT/C,_/ . F_-rF,,.e r
,jo) F OK PKOGI_/I,_If/IIE_
?n L__ _: ,_-_J I'_>
2 ------ r-
' _ --1"_Im_'A_ I I I
!___ ................ _ _
.... i - F------1_n _ _ _ .50_,e IP/T(HI--J_--IF-,,vv _ _ --bH_I I_'F_ 37£ZZA£ I-------I i i
_.- ......._-_ " I ' l
I _ .'TAC5CC,V-/-_OZ.C
{ r---j ................... -'rqF-- I/I I " _q /
, L__
b,
2
9-3
1966018034-020
F,-;T_
ROLL STABILIZED PLATFORM iIi
Ii
I
PLATFORM !_
TACHOMETER I
ROLL GYRO
iTORQUER SYNCHRO t-
O c¢_,'r/_'v4DsI_c" 7#20-1_)
SLAVE ROLL GYRO
Figtu-e 3. FACS Roll and S_
!
1966018034-021
ENABI.E
(,) o e,Rt_ 94ZA./_
Su _f.,o Z _lr
I
I
I
t _ -- I,EMO_ _ FULL
--@,'V'- L j (-_:_:, J ,-,,,,,B_rk7 (z) _A-,-,-,'4zA_o)
Op.rlt-,4L )
() i .E',Y1/ I _I: :--:--_--I1,. _-_-------I RELAY I .... I
............ "1 oRivE/ I I - ',eL",_ 74ZA IO L_J_ __
5,''."'' K3(,) -- _Lv-__V.LV_
ROLL RaTEI GYRO
.____ E'_-q _ Rr'LAY I"....
TORQUING VOLTAGE
& 4_._ cw (ov,o')
_ve Roll, Block Diagram
i0
1966018034-022
3.1.1 FACS SEQU]_NCE OF OPERATION
>,1.1.1 BEF01_ LIFTOFF
External power is applied to the system 20 rain prior to launch.
The offset conditions required to compensate for gyro drift, tower tilt, and
launch delays are detenmined and appropriate offset coz_ands are applied to
the g_Tos.
3.1.1.2 POWERED FLIGHT
During powered flight the gyros m_intain their off: -+-caged posi-
tion except for small drift. The predictable portion of this drift is taken
into consideration at the time of introducing offset commands. At burnout the
gyros provide the inertial reference upon which the progr_._med maneuvers are
_f based.
3 1.i.3 SUSTAINER BURNOUT
At sustainer burnout, the tllrust decay activates the propellant
shutoff valves. Actuation of the "g" reduction switch initiates action of a.
unijunction tLmer by energizing self-locking relay KI(P) . The time-delay de-
lays the despin operation until the vehicle altitude is sufficient to minimize
r011 aerodynamic moments.
3.1.1.4 _SPIN AND ROLL CAPTURE
Upon completion cf the delay-time interval, the timer circuit
energizes self-locking relay _(P) which arms the desp_n and roll-control valve
circt -.;"(3.) , and also provides the first of two "AND" No. 1 signals needed forF
progression of the progra_.er sequence.
At this time the roll control channel is receiving position-plus-
rate information from the roll Stabilized platform and the roll rate gyro.
* _(P) designates programmer relay, (I) designates IACS control unit relay,and (S) designates SACS control traitrelay.
** Parenthetical numbers refer to points designated in Figures 2 and 3-
ll
1966018034-023
The presence of a vehicle CCW spin rate turns on the despin valve. The despin
valve remains on until the roll positlon-plus-rate signal is reduced to within
the switching thresholds. The roll control channel continues rioproduce appro-
priate valve switching action until the vehicle is oriented to the roll gyro
mLll and body roll rate is low. The first turn-on of the roll CCW valve ener-
gizes self-looking relay KT(I), thus disabling the despin valve and permitting
the roll CW valve to respond to switching commands. Energization of rel_y KT(I)
also enables the IACS pitch and yaw va!_re drivers. Since the output signals of
the pitch and yaw position gyros are grounded, the valve dr-ver circuits operate
off the rate gyro signals and thereby provide rate stabiliz:_tion during the re-
maining period of roll capture.
At completion of roll capture_ when the absolute value of the roll
position error is reduced to within a fixed threshold level 3 the second necessary
"AND" signal (2) is provided to the sequence logic at "AND" No- ]. Suitable
filter action in the absolute value circuit prevents premature zontinuation of
the sequence should the condition of zero position error plus high rate occur.
Presence of the necessary inputs at "AND" No. 1 results in program-
mer output (3) energizing relay Kg(I) which isolates the pitch and yaw position
error signals from ground and results in position-plus-rate control of the T_ACS
va-_e trigger circuits. Relay Kg(I) can be wired to provide a self-locking con-
tact. In this configuration, position_plus-rate control is maintained without
subsequeut interruption. Progra_zJer output (3) also energizes relay K3(1) "which
reduces °roll rate gain after initial capture. Relay k_(I) can be wired to pro-
vide a self-locking contact. When used, the low va],'eof roll rate gain is
maintained without subsequent interruption.
5.I.io5 PITCH AND YAW CAPTURE
Completion of despin and roll capture permits r_aoval oI any pitch
or yaw errors. The presence of error signals produces appropriate control valve
action to orient the vehicle to the pitch and yaw g_o nulls and thus reduce er-
row signals to a low value.
The absolute valise dstector circuits in the pitch and yaw charmelsQ
provide inputs (4) and (5) to the pro_r._mmer, and also energize relays El(I) and
12
1966018034-024
K2(1) used for rate-gain change. The rate-gain is automa%_cal]y selected, de-
pending upon wnether position error is greater oc less than the threshold of
the half-trigger following the absolute vait,e circait. Relays F_(i) and _2(!)
are energized when the position error is less than the triggez level.
3.1.1.6 SLAVE OUTER GLM_&L OF I\&WG'fRO
Pitch and yaw position signals (4) and (5) togevher witn roll-
position signal (2) indicates completion of 3-axis capture. These inputs are
applied to "M_D" No. 2. The fourth condition necessary at "AND" No. 2 is al-
ways present when gFTo torquing is not in prccess (i.e relay K3(P) is de-
energized). The presence of all four inputs at "AND" No. 2 produces a program-
mer output at (6) which triggers an SCR and enables the slaved-roll torquing
relay drivers. These drivers control actuation of relays K4(i) and KS(1) to
apply torquing voltages as necessary to b_id the slaved-roll g_nbal near null.
This function is uninterrupted for the remainder of flight.
. 3 •i •i •7 BEGIN PROGRAMMED MANEUVERS _TD HOLDS
The program sequence is now ready to begin the programmed maneu-
vers and holds. When the output from "AND" No. 2 is present, and flip-flop
No. 1 is in the "zero" statej "AND" No. 3 provides a trigger fer the one-shot
multivibrator. Flip-flop No. 1 is held in the ze_o state in the le_ex start
position. Subsequent ledex action removes this "hold-zero" condition, and
thereafter flip-flop No. i can be put in the "zero" state only at initiatl, _ r_
gyro torquing. Flip-flops Nos. 2 and 3 are each held in the "one" st._te in the
!edex start position.
Action of the one-shot mILltivibrator provides a p,Jms.= which:
a. Puts flip-f].cp Nc. i in "one" state. (With fl_p-flop No. iin the "one" state, changes in output of "AND" _, . 2 areprevented from initiating repeat one-shot action. )
b. Places flip-flop No. 2 in the "zero" state thereby initiating
the hold time_ (i.e., relay KT(P) is de =nergized, therebyremoving the shunt around the t_.ming capacitor, and the in-tegrator is permitted to oper_,te).
c. Steps the ]edex one position.
13
1966018034-025
3.1.1.8 FIRST HOLD
Each ledex position establishes a hold time and maneuver co_nand.
The function of each ledex deck is as follows:
a. Ledex @_ck No. 1 controls the actuation of relays to makethe appropriate selections on the sign and axis of _mneuver.The maneuver itself does not occur until after the hold-time
interval is over. Relay K3(P) determines the direction ofmaneuver, and relays K6(P) and KS(P) establis] the axis ofmaneuver.
b. Ledex deck No. 2 provides the resistance value required bythe timer-integrator to produce the desired hold time andp-ovides a signal to flip-flop No. 4 in the SACS when SACSoperation is _ -_ ^__e_r_.
c. Ledex deck No. 3 provides a patched-in comparison voltageto _he comparator and trigger, thereby fixing the magnitudeof the maneuver (i.e., angle through which the gyro istorqued).
d. Ledex deck No. 4 provides a digitized output which permitsidentification of the ledex position at any time.
When the hold-time interval is complete, the output of the uni-
junction timer puts flip-flop No. 2 in tb_ "one" state thereby resettir_ the
timer (i.e., energizing relay KT(P), and puts flip-rio I No. 3 and flip-flop
No. 4 in the "zero" state.
5.1.1.9 INITIATE FIRST_
Placing flip-flop No. 3 in the "zero" state actuates the torque-
control relay driver. "@hen the torque-control relay K3(P) is energized:
a. Torquer voltage circuits are completed and torquing actionis started. Since ledex deck No. 1 has established maneuver
parameters, precession of only one of the gyro gimbals oc-curs. If the maneuver is in either the pitch or yaw axes,
relays K6(P) and K8(P) apply an input to the torquing-controlintegrator to compensate for variations in gyro inner gimballag angle. (A discussion of lag angle compensation is in-eluded in Appendix X.)
b. The shunt around the operational amplifier is removed_ there-by permitting integration of the torquer voltage and current.
14
1966018034-026
c. Logic voltage is applied to place flip-flop No. I and flip-flop No. 4 in the "zero" state; _oncurrently the fourth in-put _s removed Irom "AND" No. 2. (A one-shot trigger can-not occur with this input removed.)
3 .i.i.i0 C(MPLETE GYRO TORQUING
Gyro torquing continues until the desired torquing angle _s_sbeen
obtained. At this time, the comparator and trigger provide an output which re-
turns flip-flop No. 3 to the "one" state. When 11ip-flop No. 3 goes to the
"one" state, the torque control relay K3(P) is de-energized and:
a. Torquer circuits are opened.
b. The integrator capacitor is discharged.
c. The flip-flop No. i and flip-flop No. 4 "zero" state ignaisare re_r_oved(the flip-flops r_nains in the zero state).
d. The fourth signal (indicating not torquing) is reapplied to"AND" No. 2.
3.1.1.11 C(MPL_I_IRSTMA_EUVER
When all necessary inputs are present at "AND" No. 2 an_ "AND_'
No. 3 (i.e., all axis error_ low, not torquing, and ±lip-flop No. i in "zero"
state), the one-shot is again triggered and the ledex is stepped. This next
ledex position can produce either a hold or a maneuver, as desired. The SACS
portion of the FACS would be operative only during hold periods.
3.i.i. 12 ENABI_ SACS
When flip-flop No. 4 is in the '_zero''state, the _CS is disabled.
When the IACS hold timer is started, a pulse is transmitted to flip-flop No. 4
in the SACS, placing it in the "one" state. The flip-flop state change provides
_n input to "AND" No. 4. This represents one of three conditions necessary at
"AND" No. 4 to permit the SACS acquisition sequence to proceed.
_t
,
1966018034-027
3-I.I.13 SACS ACQUISITION
When both the pitch and yaw gyro errors are below a desired thres-
hold value (0.4°) the output of half-trigger circuits provide the remaining two
conditions at "AND" No. 4. With all three inputs present, time dela:yNo. I is
pernlitted to operate. When this condition persists for the time-delay interval,
relay KS(S) is energized thereby enabling the relay drivers in the pitch an4 yaw
gyro torquing circuits and enabling the iACS-to-SACS valve switchover circuits.
Once K5(S) has ene.gized, it is held energized through another relay driver which
is operab]e so long as flip-flop No. 4 remains in the "one" state.
A similar sequence applies to "AND" No. 6, time delay No. 3, and
rels,y K3(S). Th_s relay provides a start signal for the stellar sensor.
With the gyr_otorquing circuits enabled, the presence ef a fine
sensor pointing error prodaces gyrc torquing toward the desired target. Gyro
torquing is controlled by relays K2(S), K3(S), K7(S) -andKS(s). In general,
ihitial gyro torquing occurs so rapidly that the half-trigger inputs at "_ND"
No. 5P and "AND" No. 5Y disappear and consequently valve switchover does not
immedla_ely occur. The IACS jets then accelerate the vehicle toward the target.
As the line-of-sight pointing _rrors become small, the gyro error
signals also are reduced. When either the pitch or yaw gyro error signal is be-
low the desired threshold level, the corresponding half trigger produces an in-
put to "AND" No. 5. This input permits operation of time delay _b. 2. When the
gyro error remains below the threshold level for the time delay No. 2 interval,
the IACS jets in that axis are disabled_ and the SACS jets are enabled. This
action is produced by relays K4(S) (pitch) and K6(S) (yaw).
The SACS jets are controlled by circuits operating off the fine
sensor output signals. These circuits consist of operational amplifiers with
le_ l-lag characteristics, triggers, and valve drivers.
3.1.1.14 EETURN TO IACS CONTROL
When gyro torquing is again initiated by the programmer, flip-
flop No. 4 is restored to the "zero" state. This removes the "AND" No. 4 input
16i
1966018034-028
and disables the K5(S) and _(S) relay driver. De-ener@izaticn cf _(S) dis-
ables the valve switc._over ,:.ircuitsand control reverts to the coarse jets.
Thc torquing relay drivers are disabled.
3.1.2 GYRO CAGING I_ERFACE
Operation of the ,3SE caging ci::uits energizes relays which _,.c-
form the following functions:
Kt(S) Connects the GSE torquing relays to the pitch gyro torquer(and isolates the SACS torquing c_rcuits).
KIO(S) Provides the same function as above for the yt_w gyrotorquer.
K4(P) Disables torque control relay K3(P) and sets flip-flopNo. 3 in the "one" state thereby preventing a_p!icationof torquing voltages through the programmer. Prcgran_eroutput (7) must be present at the GSE before Lorquingvoltages are applied from the GSE. 'This insures that re-lay K3(P) has been ae-energized.
K6(1) Disables all pitch _nd yaw valves; enables the _%CS valvedrivers. The valve drivers az°e used to provide a GSEmonitor of the driver circ,_its.
KS(1) Isolates the pitch and yaw position gyro demod outputsfrom ground so that position signals are transmitted to
the valve-drive triggers.
Operation of the GSE caging circuit _iso enabJes the s]av=d roll
torquing relay drivers, thereby caging the slaved roll g_mb6,i.
3.1.3 CONTROL PAR&METERS
For convenience_ block diagrmns have bee'- prepared to show param-
, eter values in the FACS contro] circuit. These diagrams include all gain terms:
filter characteristics, and trigger levels. Fig_me 4 shows pitch and yaw chan-
nels for both the IACS and SACS. Figure 5 shows the roill _od slave _o]] channels.
Figure 6 shows the convention ex_p!oyed for rolL, pitch, _.ndyaw,
t,_dy axis definition, and direction of rotation.
17
1966018034-029
"]8
1966018034-030
1966018034-031
J
VIEW LOOKING AFT
MOTION OF VEHICLE NOSE
I: I ROLL CW JET
VEHICLE
_TJET 1 e_ J_'I PITCHCCWII.I
SOIA__ SENSOR I
I
JET2 I JET 4Y_;_ CCW I YAW CW
PITCH ___ ....
AXIS I --_--_CWREFERENCE I
YAWAXISREFERenCE
Figure 6. FACS Body Axis Definition
1966018034-032
The polarity of _ signals and phase of AC signals in the FACS
Js related to angular rotation about the body axes in Tables i and 2. l'able I
shows the IACS sign and polarity designetions and Table 2 shews the SACS
des ignations.
3.2 BREADBOA!RD FACS
Photographs of the breadboard _ACS structure_ with all of the
subassemblies mounted thereon, are shown in Figures 7, 8_ 9_ and I0. EacY.
photo shows a different quadrant of the cruciform-shaped structure. T_ere a.r__
two compartments in each quadrant _'ol"a total of eight subassembly
compar treents.
All of the breadboard subassemblies: except for the "J" box_ are I
easily removable from the main ,TACSmounting structure. The "J" bcx_ and as.-
sociated system pig-bai] harnessing; was assembled on tlhe struct_re. The r_'o-
grammer, IACS control _lectronics, SACS control electronics_ and telemetry sig- i
conditioner are.all plug-in units to the main structure. The photograph in
Figure 8 shows the structure harness/subassembly plug-in connector' t.echnique
_ser]fo±'these four units. The va.ca,nt compartment (spare] showo in the ?note
was later used to mount the GSFC delay__d-fcedback circuitry for the SACS.
3_3 BREADBOARD GSE
The FACS breadboard ground support equim_ent is s_owf_ i,qFigures
ii, 12, _nd 13. This equipment was used for s/stem c.heckout d,,r'i<£,t,h_bench
bests ,_.tSGC and the 3-_xis simu].ator tests at GSFC. The GSE _onsc ]. I:r'r_id_s
:<]Inuc'c-_:":_,ryswitching control and gyro caging (or cfFset tzgi:_g) <_zc.uilt$
require8 for full remote control of the FACS during test. The GSE is connected
to t},eFACS, e.xcep[,during .5-axis tests, via an umbilical ca.bie. Wb_.omore
complele ir_formation about tae system is required during st.'-Jtictests, a test
('.ableis provided i'or Further intercc_necticn between the system an,_GSE.
21L
1966018034-033
22
1966018034-034
25
1966018034-035
J
'" " 1966018034-03(
Figure 8. Breadboard FACS, View No. 2
J
1966018034-037
27
1966018034-039
d
28
1966018034-040
Figure 12. Breadboard GSE, Panel
2£
1966018034-041
3o
1966018034-04:
3.4 FACS SDVSASS_BL]]_S
The breadboard FAr;S is divLded into ten major sqbassemblJes as
follows :
Static Inverter Telemetry Signal Condizioner
IX:Power Supply "J" Box
Programmer Roll Stabilizer Pl_tform
.IACSControl Electronics Rate Gyros
SACS Control Electronics Fine Sensor (Stellar cr Solar)
Complete subassembly detailed functional descriptions_ schematic
diagrams, and component layout drawings are presented in Appendix I. A comple%e
parts list of all the F&CS subassemblies is presented in Appendix !I. Test data
from the bench tests for the subassemblies (and the modules contained within
them) are presented in Appendix IV.
3.4.1 STATIC INVERTER
The static inverter is a sine-wave_ 2-.pnase_ D2-to-AC inverter.
All of the 400-cycle A0 polyp, for the FACS and supporting GSE is supplied by
this subassembly. A photograph of the breadboard static inverter is shown in
Figure 14. This photo was taken pzior to bench testing and therefore doesn't
show the heat sink transfer blOoCk into which the output power transistors were
later mounted. During the static inverter bench tests_ all of t__e specified
requirements for the AC power supply described in Section 2 of this zeport were
achieved.
3.4.2 DC POWER SUPPLY
The FACS logic and contrci circuits require a __15-VDC power
supply, The requirements for the DC powe-r s_,pply.,Section 2 of this report_
were modified pr]or to construction of the breadboard. T'neoriginal GSF0 re.-
quirement was that the static inverter be the scurce of input powtr for both
the positive and negative !X7regulators of the DC power supply. Approval to
31
1966018034-043
supply only the -ID-VDC regul._tor by the static inverter, aud to t,_-e,_Seunreg-
ulated + 28 V_] of the .?ACS for the _ l_)-tr_;regulator, was L%ter ac'_uired from
GSFC. A photograph oi'the breadboard DC power supply is sr_owc_in l.'igure?-5.
The programmer' subassembly includes the necess-_ry Icgic/timiug
circuitry for coast-time delay, maneuver-cor._r..arldstorage_ gyro tcrquing_ target
viewing time_ and sequence contrcl.
The programmer contains all of the system logic and sequenc fr_grc-
quiz'edfor use of just the IACS portion of the FACS in the IACS mooe. &dditio_]-
_'_ _ provided at the interface _iLh the SACS con-ally, appropriate logic ._zo.._l_are
trol electronics to enable the SACS circuits at the start of tar-get-bclding_ and
to dis_.b.lethe SACS circuits u_on start of IACS maneuvers.
A patchboard panel is incorporated in the prcgra_,_nerto provide
maximum flexibility with m_n.im_n time required for prcgra_ning. The patc'_board
panel consists of a printed circuit matrix where the ve_ " i and horizontal
strips are on opposite sides of the board. Small screws connect a horizontal
and a vertical crossing point tc effect a progra_n function.
Program functions that are patched :nclude the a_is and direction
for each maneuver_ and the sequence oi'hold times cn eacn target. Duration of
each "hold" is determined by resistors mounted on a terminal strip next to Lhe
patch-board panel. Maneuvers an@ holds can be patch-programmed in any sequence
desired by the experimenter. The magnitude of each maneaver is seLe:-_ed b2 seL-
oing pre_:ision potentiometers for"a suitable reference voltage to be ,_.pp.].i_dt,
the comparator circuit in the variable-time-torquing section of the progra_mer.
Photographs of the breadboard programmer are shown in Figures 16 and !7.
5.4.4 IACS CO_I_ROL ELECTRONICS
The IACS contz'ol electronics subassembly contains t.herequired
coutrol circuitry for the roll_ pitch and yaw high thrush valves as wei),as lh_.
slaving of the _aw gyro outer gimbal. Also included in [he IASS conl.ro] ele,-
tronics are the absolute value level detector circaits which monitor the position:
1966018034-045
34
1966018034-046
J
°.
J
1966018034-047
36
1966018034-048
gyro error signals in roll, pitch and yaw, and provide an outpui which indicates
vehicle "capture" in each respective axis. fhese "capture" cuipuis are _sed to
control bi-ievel rate gain in the coarse control circuitry and also are used by
the programmer for program locic sequencing. Photographs of the iA£S control
electronics subassembly arc shown in Figures 18 and 19.
3.4.5 SACS CONTROL ELECTRONICS
The SACS control electronics subassembly contains all _he logic/
timing and control circuitry necessary for the adaptation of an IACS to a full
FACS configuration. Provision is made for all logic and sensing circuitry needed
for _ ...._ _^ "_*'_L,a_ _qu_o_l_,, and subsequent +_o_e__._...._......n_ control fr<_r:th_ !ACS to the
SACS.
The SACS contrcl circuits mmplify and shape the fine semgor output
to provide position-plus-rate signals to the switching circuits that drive the
fine control valves. Provision is also made for gyro torquing control to pro-
duce the desired correspondence between gyro and fine se_or reference. Photo-
graphs of the SACS control electronics subassembly are sho_m in Figures 20 and 21_
I
3 -4.6 TE_TRY SIGNAL COiTDITIONER
The telemetry signal conditioning subassembly provides pre-
telemetry conditioning of all monitored signals from the FACS. All outputs
from this unit are conditioned zero to _+5 VDC (with _he exception cf the 400-
cycle frequency monitor which is fed directly to the transmit%er of the te!em-
etry system being used) f-or ready use by most telemetry syst__ms in general use.
Photographs of the T_lemetry Signal Ccnditioning subassembly are
shown in Figures 22_ant_ 23. A complete calibration procedure of this unit is
presented in Appendix VI.
3.It.7 JUNCTION BOZJ
All of the FACS subassemblies are interconnected in the "J" box
shown in +,helower compartment of Figure 9- The "J" box is the central distri oc
L i
bution point of all system power and c----..a_ns the power switchover relay for
transferring fr6m external t.e internal -_28-gI_ battery power.,_
#
• , j
1966018034-049
1966018034-051
4o
1966018034-052
43.
1966018034-053
_2
1966018034-054
1966018034-055
_.4.8 POLI. STAB!LYZFD PLATgORM
The roll stabilized platform (RSP) incorporates two free gyro_
which provide the inertial reference for the IACS. TL[_ _uha_:sc_fi_J.y[_a_under'-
gone successful development and flight test. A photograpL of't_Le PSP is sl_own
in Figure 24.
ne platform mount is servo _riven to continually nu±l the out-
put of the roll gyro synchro, thereby maintaining an essentially sbable roll
p_..tiorm for vehicle spin rates up to 5.0 rps. A tachometer_ wbic0 senses pla8-
form rate relative to the vehic!e_ provides the necessary damping° Vehicle roll
position error is obtained by combining tns outFut signals from the roll gyro
synchro and from a platform position sy_ _ro. This technique effectively elim-
inates any platform dynamics from the vehicle roll-control loop and t_e roll-
gyro caging loop. The inner gimbals of the two gyros provide the pitch and yaw
reference. The FACS RSP will meet all of the requirements specified in Section
2 of this report.
3.4.9 RATE GYROS
The rate gyro subassembly contains the roll_ pitch and yaw rate
gyros that are used for rate feedback stabilization of the IACS control loops.
The three rate gyros fomn a single subassembly similar to that shown in
"_ Figure 25.
3-5 SENSOR
The FACS is designed to be suitable either as a solar pointing
or stellar pointing system. Under separate procurement, GSFC has contracted
for development of a suitable stellar sensor. To permit earlier flight test_
of the FACS_ the Phase I and P_se II FACS programs utilize a solar sensor de-
_eloped by GSFC. The solar sensor has been designed to have a similar output
characteristic to that of the planned stellar sensor_ t.flusfacilitating conver-
sion from a solar pointing to a stellar pointing FACS_ and.vice-versa.
44
1966018034-056
1966018034-057
1966018034-058
IThe GSFC solar sensor utilizes four Ball Brothers -_me _-_-_
calibrate_ silicon photo-voltaic ceZls as the basic sensir_ elements. _.ese
four photo-voltaic cells are mounted on a solid metal block. Tb.e block esxab-
lishes the necessai-j relative alignment of the four cells, and provides a heat
sink to keep the seDsor at minim_n drift when the cells are co_mected in pairs
of oF_osing po!arity.
_.e output of each cell-pair is amplified in a Burr Brown Model
1903 oyerational amplifier. In the breadboard version, amplifier gain was ad-
justed to provide the desired output sensitivity near null of 5.0 _/arc sec
when o_erated with a _._Ipar, _c., _-kgdelSS-4 Solar-So-_-ee Sim-ula-_or, which
•has an intensity of approximately 1/60 t_hat of the sun iD sp_ce.
The linear field is approximately + I_ arc minutes wide. Saturated
signals persisg out to about + lO °. The useful range of the sensor duri_ t_hree
-axis simulator tests was about + 1°. This limitation was imposed by the _-inch
diameter of the collimated solar source sJm_alator.
1966018034-063
Section 4
FACS PHASE I PROGRAM
4.1 WOKKSTATEMENT ITEMS
SGC shall provide the facilities, materials, and personnel neces-
sary to furnish the following items:
Item 1 - SGC shall prepare a complete set of electrical schematic
diagrams and a test outline covering plarmed tests for
the major components and subassemblies of the proposed
Fine Attitude Control SystEm (FACS) for the Aerobee 190
sounding rocket. SGC _hall also prepare a complete func-
tional description th:_t ties in with the schematic dia-
grams and which covers the step-by-step operation of the
system. The schemaz_e diagrams and ftmctional descrip-
tion must be approveg, by GSFC prior to construction of
the breadboard FACS. However, procurement of key com-
ponents in the brea(board FACS can be initiated prior
to such approval. 'fhe test outline must be approved by
C_FC prior to act[_.l testing of components of the FACS.
Item 2 - SGC shall conduct an analysis of the fresent IACS flight
pneumatics.
Item 3 - SGC shall conduct a comprehensive single-axis analog
simulation of the FACS. SGC shall prepare a report
covering the analog study.
Item 4 - SGC shall procure a solar simulator to permit checkout
of the integrated FACS.
Item _ - SGC shall construct a breadboard FACS in accordance with
the GSFC approved design using the control parameter
values determined from the analog optimization stuccr.
Item 6a - SGC shall conduct bench checks of the breadboard FACS
at SGC in accordance with the approved test out].ine.
Item 6b - SGC shall deliver the bench-tested breadboard FACS to GSFC.
Item 6c - The FACS three-axis simulator final acceptance testing shall
be at GS_C on the Aerobee simulator. SGC shall provide the
necessary liaison and technical services during the period
of the three-axls simulator tests and acceptance testingat GSFC.
48
1966018034-064
Item 7 - Task deleted.
Item 8 _"- _-_ shall prepare a final report on the breadboard FACS.
4.2 D_$IGN
_ne basic structure that houses the FACS electronics in an all
welded and machined aluminum crucifcrL_ and ring-deck arrangement, as shown in
Figure 8. __is type of structure maintains acceptable dimensional stability
and rigidity to insure that the seusing elements and the attitude-control ref-
erences are accurately aligned at all times, and tb_t the balance of the entire
FACS-Simulator assemoly is not aisturbed on the air bearing. Machined surfaces
and alignment marks were used to provide the alignment of the solar seusor,
_oll-stabilized platiorm_ and rate-gyro package, in relation to each other and
to the FACS-Simulator interface. The open cruciform mountin_ compartments in-
corporate excellent access and serviceability in a rigid configuration° All
equipment and unit attachments_ as well as c_bling tiedowns, are machined into
the structure. The resulting FACS package o_ inches in diameter, and 20
inches long, not including the fine sensor.
The breadboard packaging design was based on a modular concept,
as specified by the requirements of Section 2.3, incorporatir_ each of the sub-
assemblies described in Section 3.4. The _rogrammer, iACS control electronics,
and SACS control electronics subassembly breadboard packaging was partially im-
plemented by the use of several small printed circuit board modules that were
modified fzo_ another SGC program. These modules included the i_ll triggers,
half triggers, absolute valve circuits, valve drivers _.nd the demodulators. In
addition, the progra_r_r used several other modifiea modules.
An example of the subassembly packaging technique is shown in
Figures 18 and 19. The latte_ shows t_ rear view of the subassembly and il-
lustrates the mo1_nting stand-offs and plug-in tec?mique used for attaching to
the main FACS structure both mochanically and electrically. This rear view
also shows the mounting of the modules. The leads of the modules, transformers,
relays, transistors, and amplifiers all extend through the vector boards to the
_ront side of the m_assembly shown in Figure 18.
49
1966018034-065
_ne umbilical ccnnector for electrical .!r,terface with the GSE _s
sho_n in the lower compsrtment of the photograph presented in Figure 7. _
photograph also shows one of She four access holes (one in each quadrant) in
the rear mounting ring for electrical interface cables interconnectir_ the FACS
and GSFC Si_,_alator.
The breadboard FACS design conforms to or surpasses the GSFC spec-
ification requirements of S_.ction 2.3 of this report. Schematic diagrams of
all the breadboard FACS subassemblies are presented in Appendix I, A complete
parts list of the subassemblies is presented in Appendix TI.
4.3 ANALYSIS
The FACS Phase I pro&2am included extensive analysis carried out
on the analog computer covering all _.spects of system performance. An analysis
was also made of the reaction jet pn_ mmtic circuits now used with Space-
General's Aerobee 190-1_OA ,%ttitude Control System.
4.3.1 PNEUMATICS ANALIBIS
As required by Work Statement Item 3, an analysis was made of the
pneumatic circuits used in the Aerobee l_O-190A. The resulting report was sub-
mitted to GSFC and is included herein as Appendix III.
Pneumatic circuits for the FACS will be designed during Phase iI
of this program. The material presented in Appendix III defines the character-
istics of presently used systems. The "high thrust" circuits of the FACS will
probabl_ b_ cimilar. However, some changes may be expected due to addition of
the "low-thrust" circuits an& to repackaging of the roll control valve-nozzle
hardware.
4.3.2 ANALOG COMPUTER STUDY
Computer studies were carried out in support of the FACS design
effort. These studies formed the basis for assessing the suitability of design
features and were used to establish settings for all parameters. A report
• covering this work was submitted to GSFC (Reference 1). The findings were
50
L
1966018034-066
closely examined at GSFC by computer studies reported in Reference 2. Good
correlation was obtained between the t_o studies.
An objective cf the program was to examine the correlation be-
tween the analog simulation and tests conducted with the FACS on a t_ee-axis
simulator. These tests are described in Section _.5. Tests results led to
some changes which were s_osequently incorporated into the analog simulation.
A series of analog computer runs was then made which duplicated the conditions
examined on the three-axis simulator. A comparison of results is discussed in
Section 4.5.7. Specific c_hanges from the analog simulation of Reference 1 are
described below. _lso ine!uded is a description of the mechanization for each
change.
4.3-2.1 POSITION GYR0 SIGNAL LIMITING!
During three-axis simulator tests_ Zener diode limiters were in-
stalled to produce voltage limiting of the position gyro output signals in the
IACS. This _ermitted a reduction in the setting of rate gain and thereby alle- |viated overdamping during maneuvers made at high control moment acceleration
levels. Section 4.5 treats this in detail and includes a definition of the ||limiter characteristics.
The computer mechanization of this change is shown in Figure 26
(block diagram) and Figure 27 (computer circuit diagram). A diode function gen-
erator was employed to duplicate the limiter characteristics; DFG settings are
shown in Table 3.
4.3.2.2 MANEUVER RATE, GAIN
Three-axis simulator tests led to selection of maneuver (high)
rate gain = 1.55 sec in the IACS pitch and yaw circuits. This change was in-
corporated in the final computer simulation where:
K1 /_ = 1.55 seconds (Potentiometer Q24 set at .0690)
The effective rate gain is increased substantially above this level
by the signal limiter as the lag angle increases beyond the break point of the
limiter.
51
1966018034-067
KI-)2 _ _2 Soft eDZL- Sz+2r_DZ _DZ4 _ _ Limiter
Modif_.e d Arrangementi i,
I Demodulator No. 2 _
e G KDZ _ZDZ eD2
$2+2_ D2 _D2 + C°ZD2
Reference I Arrangement
Figure 26. IACS Position Slgnsl Llmiter Charge, Servo Block Diagram
_2
1966018034-068
- VeD2(eD2Li
DFG 1 Low
""f_bl_ 3"?_ Sensitivity
Sensitivity" OL_A
Wire _hange _ OR "
Modified Circuit i,t_?
. _
-VeD2{eD2}
Reference 1 Circuit
Figure 27. IACS Position Signal Limiter Change, Analog Computer Circuit
I
_3
1966018034-069
Table 3
DFG SETTINGS FOR POSITION SIGNALLIMITER SIMULATION
Segment QJadrant Gain Breakpoint Slope
i CS .... 8.2
3 2 Low 8.2 ii.4
4 2 Low 14.0 17.3
5 2 Low 33.2 28.0
6 2 Low 75.4 --
ll -CS ..... 8_2
13 2 Low -8.2 -Ii.4
Z4 2 Low -14.0 -17.3
15 2 Low -33.2 -28.0
16 2 Low -75,4 --
Parallax = 0
4.3.2.3 VALVE CHARACTERISTICS
The high-thrust (coarse) valve characteristics were adjusted into
closer corres_)c-i_uce with valves used on the GSFC simulator. The low thrust
(fine) valves were set to the "C" characteristics of Reference 1. Res#onse
characteristics and potentiometer settings were as follows:
Fine CourseValves Valves
Time to energize (sec) .012 .010
Time to de-energize (sec) .017 .019
Potentiometer Settings: Q25 = .0094 Q05 = .0194
%9-9= .oo94 %12 = .o194
Q27 = .2000 Q04 = .0178
Q.15 = .2000 Q,ll = .0178
54
1966018034-070
h.3.2.4 MtuNEL_WERTORQUING
Initial t_sts on the three-axis simulator indicated a discrepancy
in maneuver (.'haracteristicsas compared to analog results. Msneuvers on the
simulator dJd not produce a steady-stace condition (constant rate, constant lag
angle) in _id-_aneuver. TM." _as attributed to an incorrect simulation of gyro-
torquing c'_aracteristics on _h_ computer.
The computer simulatioo was corrected by modifying the gyro-
torquing characteristics from
ic = (_c)man = constant
to the following :
_c = (_c)man cosl@ c
Mechanization of this change is shown in Figure 28 (block dlagram)
and Figure 29 (computer circuit diagram).
A techniual note discussir_ the effect of gyro torquing character-
istics on maneuver characteristics was submitted to GSFC. This note is reproduced
in Appendix VIII. It does not i_clude the position limiter effects. Therefore,
the recommended change in rate gain was superseded by the introduction of limiting.
4.3.3 ROLL 81AVINGANALYSIS
In the FACS, slaving of the redundant gimbal of the yaw gyro is
deferred until three-axis capture is complete. This method was questioned at
the tire of proposing. An analysis was prepared to justify the approach. For
completeness, the analysis is included in App_ndix iX.
4.4 BENCH TEST
Bench checkout of the breadboard FACS was performed in three
phases. The first phase involved testing of the electronic modules to insure
compliance with design requirements prior to installation into subassemblies.
. Phase two of the bench test was a subassembly calil,ration and functional
1966018034-071
. -e B
(q_C)man M5KI00 K T
Modified Arraugement
"o
+_C
,.,_ i I _-"• ,,'r I -eB
q (_C)man. MSK100 K T
I
Reference 1 Arrangement
Figure 28. Maneuver Torquing Change, Servo Block Diagramt
1966018034-072
Modified Circuit
: : _l "a1(%/z)
-- I
_, -eB
t
Reference I Circuit
Figure 29. /aneuver Torquing Change , 8ervo Block l)iagram
57
i
."1
1966018034-074
checkout at the environmental temperature extremes. Phase three _nvolved the
functional checkout of the completely integrated breadboard FACS at the environ-
mental temperature extremes. Also included in the systems bench test. of phase
three were functional tests performed on a single-axis simulator and on the SGC
3-axis simulator. A solar simulator was used, during the si_g!c-_xis tests, to
functionally test the fine sensor while operating with the breadboard FACS.
The 3-axis tests performed at _u_ were limited to functional operating tests to
assure proper operation apon arrival at GSFC.
4.4.1 SUBASSE_LYANDMODULE TESTS
Each of the FACS breadboard subassembiies was individually tested
to verify its stability of calibration and proper functional operational behavior
under a variety of operating conditions (e.g., varying supply voltage, loading,
signal level, temperature, etc.). Each subassembly was subjected to_ and tested
over, a temperature range from +40°F to 120°F in accordance with a test outline
submitted to, and approved by GSFC. The bench test data for all of the subassem-
blies is presented in Appendix IV.
All of the pre-fabricated modified modules used in the subassemblies
were functionally tested prior to installation. The full trigger, half trigger,
absolute valve circtit, and demodulator modules were fully tested for stability
and functional operation at the temperature extremes. The test data for these
modules is included in Appendix IV.
4.4.2 SYSTEM TESTAND CALIBRATIONt
Calibration of the breadboard FACS was performed without the roll
stabilized platform, rate gyro package, or the fine sensor connected to the sys-
tem. The connectors normally inserted into these sensors were used to apply in-
put signals for static calibration of the various gaius and trip levels through-
out the system. Tests were conducted _o verify the s5ability of calibration and
proper functional operation through the temperature range. Calibration of the
telemetry signal conditioning circuits is presented in Appendix VI. The bread-
board FACS calibration and system bench test data is presented in Appendix V.
_8
1966018034-075
After calibration and temperature testing the breadboard FACS,
the system was tested on a single-axis simulator in conjunction with a solar
simulator to verify proper operation of the fine sensor with the completely in-
tegrated breadboard FACS.
The final test at _GC, prior te shipment to GSFC, was performed
on the SGC air bearing simulator. _o teJt runs were made. The first run was
conducted with the system in the "IACS only" mode of operation to examine the
basic system operation. The second run on the simulator was designed to es-
tablish that the system would transier from IACS to SACS control of the vehicle.
Neither solar source nor fire va!vss were implemented for this test run. The
object of the second run was to verify overall system readiness for shipment.
4.4.3 VTT TEST
The FACS incorporates an improved technique for maneuver angle
control. This technique is based upon an automatic adjustment of the gyro-
torquing time to compensate for temperature and voltage variations. The ap-
proach has come to be known as the "Variable-Time Torquing" concept (VTT).
As implemented in the breadboard FACS, both current and voltage
at both windings of the gyro torquer are monitored. DC voltages proportional
to these quantities are summed together with a DC reference voltage and inte-
grated while gyro torquing is in process. The integrator o_tput is compared
to an adjustable voltage which is set to provide the desired maneuver angle
and torquing is terminated when the integrator output exceeds this voltage.
GSFC breadboarded and tested the VTT circuits. Excellent results
were achieved with a modified circuit which utilized only the current-monitoring,
and reference-voltage portions of the circuit. This modification (the "current-
only" mode) results in simplification of circuitry. SGC was directed to conduct
tests thereof and to make recommendations for the final form of VTT circuits.
A series of tests using four FMIOG-2 gyros was made. The results
of these tests _ere reported in Reference 3. During GSFC-SGC coordination meet-
ings at the end of Phase I, the "current-only" mode was selected for incorpora-
tion in the prototype FACS.
59
1966018034-076
4.j THREE-AXIS SIMULATOR TEST
Final acceptability of the breadboard FACS was demonstrated in
the three-axis simulator facility at GSFC, Greenbolt, Md. Figure 30 shows a
photograph of this recently-completed facility. The centra_ gas-bearing sup-
ported structure is housed within a light tight enclosure. A Melpar, Inc.,
Model SS-4 Solar-Source Simlator provides an image of the simulated sun in
a 5-inch collimated light beam which is directed toward the forward end of
the structure. The FACS was mounted upon the structure and the solar source
simulator was aligned with the FACS solar sensor. The gas-bearing-supported
structure incorporated a 28-VDC battery pack, telemetry equipment, solenoid
valves and nozzles for reaction jet control of attitude, and nitrogen gas
storage for the reaction jets. The facility also included auto-collimator
equipment for monitoring pitch or yaw angular position near the target-
pointing null region.
This facility provided the capauility for evaluation of FACS per-
formance, essentially free of restraint, through despin, maneuvering, acquisi-
tion, and limit cycle operation.
4.5.1 TEST DESCRIPTION
The objective of the three-axis simulator tests was to show con-
formance with all requirements for FACS operation. Additionally, a comparative
evaluation was carried out to permit selection of the best of the four alternate
configurations examined during the analog study.
A fixed program, suitable for all tes_sj was incorporated in the
FACS programmer. This program is outlined in Table 4. It provides for maneu-
vers in both directions in each control axis, four on-target holds periods, and
four target-acquisition se_lences. Since only a single solar-source "target"
was employed, all acquisitions subsequent to the first were accomplished by pro-
gramming, in sequence, maneuvers away from and returning to the target pointing
orientation.
In the target-pointing orientation, the FACS controlled p_tch and
yaw attitude to maintain the vehicle roll axis pointed at the solar source.
6O
1966018034-077
63.
1966018034-078
Table
BRF_DBOARD FACE PROGRAMMER SEQ'JENCE
FOR 3-AXIS SIMULATOR TEST
Time Maneuver Axis Maneuver
Program Delay and MagnitudePosition (see ) Direction (Deg)
i 0 Yaw CW 75
2 65 Yaw CW 30
3 0 Yaw CCW 30
4 65 Pitch CW 15
5 0 Pitch CCW 15
6 65 Pitch CCW 20
7 O Pitch CW 20
8 270 or 65 Roll CW 30_adjusted)
9 0 Roll CCW 30
i0 0 Yaw CCW 75
ii 0 .......
Roll attitude control maintained the yaw axis vertical (i.e., the yaw plane was
horizontal). In this orientation, sctivity in the yaw plane was esser_tially
free of gravity effects whereas the pitch plane activity was occasionally in-
fluenced by a less-than-perfect balance of the simulator.
The typic&], operating sequence for each test was as follows:
a. Vehicle oriented approximately 75° yaw displacement fromt_rget.
b. All systems on, remove umbilical.
c. Manual roll spin-up (this step was frequently omitbed toreduce gas consumption).
d. Automatic start signal to FACS programmer.
62
1966018034-079
• II
e "Coast-Tzme delay.
f Despin and roll capture.
g Pitch and yaw capture,
h Yaw 75° maneuver.
i Target acquisition.
j Target-pointing iLmit cycle.
k, Maneuver and hold sequence (as outlined by Table 4) culminatingin final 75° yaw maneuver return to initial orientation,
i. IACS limit cycle,
m. Insert umbilical and shutdown.
During each test_ telemetry data were transmitted to a receiving
station located outside the facility enclos_re. A listing of telemetered func-
tions is shown in Table 5. Real-time recording of eight selected functions pro-
vided means for quick look interpretation of results. All functions were re-
" corded on magneti_ tape and replay recordings were made _s desired,
Continuous recordings were made during each test utilizing an auto-
collimator in conjunction with a mirror mounted on the aft end of the simulator
structure. These data were used to correlate the actual yaw angular displacement
with the displacement indicated by the corresponding output signal from the solar
sensor.
The solenoid valves used for reaction jet control exhibited the follow-
ing characteristics at 200 psig inlet pressure:
Open Response Close ResponseValve Time - ms Time - ms
Pitch and Yaw High Thrust 8 17
Pitch and Yaw Low Thrust lO 17
Roll 16 14
63
1966018034-080
Table 5
TELEMETRY MEASUP"!4ENTS FOR _REE-AXIS SI_,_I,ATORTEST OF FACS
Channel Measurement
1 +5 VDC Telemetry Reference
2 Electrical Ground
3 Yaw High-Thrust Values
4 Program Position
5 "G" Switch and Arm Roll
6 Pitch !_w-Thrust Values
7 Yaw Low-Thrus, Values
8 +IS-VDC Monitor
9 -15-VDC Monitor
lO 26-V/O°Monitor
ii 26-V /90o Monitor
12 Pitch Position Blomap
!3 +28-VIYJMonitor
14 Roll Valves
15 Slave Roll Torquer
15 Yaw Torquer
17 Pitch Torquer
18 Roll Torquer
19 Eoll Position
20 Slave Roll Position
2i Pitch Position
22 Yaw Position
23 Roll Rate
24 Pitch Rate
25 Yaw Rate
26 SACS State
27 Yaw Valve Switcnover
64
1966018034-081
Table 5 (Continued)
TEiA_METRY MEASUR_4ENTS FOR THREE-AXIS SIMULATOR
TEST OF FACS
Channel Measurement
28 Torque Loop Closure
29 Pitch Valve Switchover
30 Sensor Pitch X i0
Jl Sensor Pitch
32 Sensor Yaw X i0
33 Sensor Yaw
34 Pitch High Thrust Valves
35 Roll Capture
36 Pitch Capture
37 Yaw Capture
" 38 Yaw Position Blowup
44 400-cps Frequency Monitor
47 28 VDC for "G" Switch
48 "G" Switch
49 +28-VDC Power
50 Ground Power
65
1966018034-082
Measured moment arms for the reaction jets were:
Pitch and Yaw High Thrust 5.55 ft
Pitch and Yaw Low Thrust 5.74 ft
Roll 1.25 ft (between nozzles)
Measured moments of inertia were:
Pitch and Yaw 322 ft-lb-sec 22
Roll 6.09 ft-lb-sec
The simulator included provisions for setting reaction jet thrust levels (and
tnerefore_ acceleration levels) by pneumatic regulator adjustment. Independent
adjustment was available for pitch and yaw high thrust, pitch and yaw low thrust,
roll thrust, and despin thrust. The adjusting regulators exhibited a r,sing
characteristic. That is, the regulated pressure increased slightly as the supply
tank presstu'e decreased. Thus, typically, the preset acceleration level was ob-
served to increase by approximately 10% in the course of a single run, In the
discussions to follow, the indicated values for acceleration refer to the
levels existing at the start of a run.
One of the simulator test objectives was to select the best of four
FACS system configurations. Differences between configurations were minor and
involved only the method of implementation of IACS pitch and yaw rate g_in and
the method of position error level detection. The configurations were cate-
gorized as follows:
Confi6uration Descriptioq
I Dual Detector, Bi-level Rate Gain
II Dual Detector, Single Rate Gain
III Single Detector, Bi-level Rate Gain
IV Single Detector, Single Rate Gain
When dual detectors are used, one initiates rate gain change and
tl_ other initiates SACS Enable.
_en a single detector is used, both functions are initiated by
the same detector.
When bi-level rate gain is used, a higher value of rate gain is
made effective during maneuvers than during limi_ cycle.
66
1966018034-083
4.5.2 MANEUVER EVALUATION
The character of maneuvers is established by parameters associated
with IACS operation and by the control acceleration (_c) produce@ by the high
thrust reection jets. The selection of"IACS rate gain provides the principle
means for adjustment of maneuver behavior. When bi-level rake gain is utilized
(Configuration I), then the level at which rate gain change occur_ exercises in-
fluence over the terminal portion cf the maneuver°
The range of acceleration examined during three-axis simulator
= Io4 to 4.0 deg/sec2o This corresponds to a pitch (or yaw)tests was from _c -
thrust variation from 1.79 to 9.0 ib for a moment of inertia of 900 ft-lb-sec 2.
These values are representative of operation in an Aerobee 190 where blowdown
operab!on results in a decreasing thrust level as gas iv used. _s previously
noted, the simulator reaction jeb typically showed a 10% increase in thrust_ and
acceleration, from run beginni_z to end. Thus the maximum acceleration runs were
usually conducted with _ = 3.6 dog/see 2 at run start. Roll control accelerationc
was generally fixed at 7.0 deg/sec 2 and the "_vq.u_tion of maneuver characteristics
was based on observabions of behavior _ pitch and ya_. Ti_isvalue of roll ac-
celeration is representative of operation in an Aerobee 150 dr.'ing the initial
period of ACS control. Despin was accomplished with an acceleration level of
70 deg/sec 2
4.5.2.± INITIAL EV_tLUATION
The initial selectior of IACS rate gain _as ba ,, o_ the require-
ment for critical damping at the lowest level of'acceler_': - Computer studies
led to selection of high rate gain = 9._ so,:_o sat:sf2 requirement. Op-
eration at higher levels of acceleration is then overd,_r_ed. The initial simu-
lator tests substantiated that very high frequency jet :_c_ion occurred at maxi-
mmn acceleration. The "hammering" i_osed on the solenoid valves was cause for
concern. Therefore a remedy was introduced in the form of voltage limiting in
the IACS pitch and yaw position channels at the demodulator output. Figure 31
shcws the experimentally-deternWned result of this limiting. It then became
possible to reduce the high rate gain and thereby substantially smooth reaction
jet activity.
0
67
1966018034-084
Fq
1966018034-085
4. _.2.2 MANKOVER EVALUATION RUNS
After incorporation of pitch and yaw position signal limiting,
the high rate gain was reauced to 1.9_ sec. Low rate gain remalned unchanged
at 1.29 sec. __n ov__.shoot of 9 to 7° was then seen after a 79° maneuver at
= 1.4 deg/sec 2. This was accepted as tolerable since testing established
that premature enabling of the SACS does not occur under such conditions of
overshoot.
Figures 32, 353 34, 39: 36j and 37 show maneuver characteristics
with configuration I for £x = 1.4, 1.9, 3.0, and 3.6 deg/sec2_ respectively.c
A c)mparison of Figures 32 and 33 reveals that a seven degree overshoot oc-
cured after the firs_ 79° yaw maneuver, where (% = 1o4 deg/sec 2, and that noc
overshoot occurred after the last yaw maneuver when _ was measured (post-run)c
at _ = 1.7 deg/sec 2. Obser_¢ation of Figure 32 also shows that SACS enabling
_ (i.e. toque loop closure) does not occur un'sil settling is complete.C
.- At _igher acceleration levels, overdamped characteristics pre-
vail. Figures 36 and 37 show maneuvers from simulator run 91 which was con-
ducted at the maximum acceleration level. Although overdamping is clear]y
evident, jet action is essentially one-sided and thus rate removal is accom-
- plished without waste of impulse.
: Parameters which are useful for comparison of maneuver character-
is_ics inc!u_e maximum lag angle (maxim'_n gyro-to-vehicle angular erl Jr), maxi-
...._ mum ?Te_h!clerate, and .maneuver time. These parameters are shown in Table 6 for
the first 79° yaw maneuver and the first 20 ° pitch maneuver at various levels
of acceleration. This table includes data for beth configurations I and IV.
In c0nfiguration I, a change from high rate gain (1.59 sec) to low rate gain
' (1.2_ sec) Occurs during terminal maneuver when the gyro error is less than 2°.
In configuration iV, high rate gain is retained at all %i_es. This minor dif-
ference has no significant effect on maneuver characteristics.
Test res_dts from the 7_ ° maneuver did demonstrate significant
variations in 3_ag an_le when operating at _ = i. 4 deg/sec 2, In Table 6, ac
co_,_rlson between runs 40 and 47 (with all conditions presumably identical)
shows a difference in maximum lag angle of more than 9°. It appears that this
69
1966018034-086
I
.1_ ,,, 111-_11111-_ i I 1 ' ' I L KIII!I]I_-[ -¢IFI]" _ ! 1_ llt-fl_ 11"17t::'t L_'t_! !!! _11 !1 ! ll!llllJ IIII!II!!q..L_U._-2"2FT..J !1 11.2-1 1!i IIIII ifl_tt._
I I [I 14z, I i t I I ! I r l II I11 _.LI_LUJw2J__I II _-Ti t !_-_I'-LIIZ4_!_! 11 tl ! i/it II 1 _Fw2&_w
:_-- I i Ii I:! : !r'Ullr_U 1711 iiT ,U-_ _-T_,7_-TTT_1_ ' _ ' ' I I ' _, , 4-'J 11, i II II !- i1_rL4._._qIilttl_-- _ Iidl I1,1 t,t,,l -I- , • _ I;, I i, i' _ ,
.q-4-!l'l I:I----I-H-ILt-I--U--]-t- i i I ; !li!ili!l.I ! -I2LLI_I]i_I: i',- T-_!lll i, It I 1"i-_-_ --__' _ ' _L_ 1-i J : II _l _. L _,__ _,'_ . ,_r-- -- "
1111111 III ll'lil',l #! i] /_.li'.''ii- i ii! i!-i-i_4,-iii ; ,I i , i-1.1-14:.i_ilil4ili l i t I i_lh_lilt I i i # I i i il !, _ N-l-l-i-! _I _1-_t-f-i; _-l-f_ -!--i-_-,I-i---t- _t,-'P/lill]l ii__lr._t ,' i!iixii_.i!_ i, _I_,_ Xfi-t It Ili/! I:II ll!-m_ ; iiiiT-i-._2iT_
1-' 2.!..i._1.1__.I._1_I__.1-t t tli 11 , i i i I !#1 1 : ! T j Iil I t i I i I i I I i i t I I ! I i I I i i ; ' i hi4 i'r_ _-_-I-1. !!! ! 'I iil / I ill_ I._L.U__III_Iii Iii ITiill! 11111 iiiil-_ll'-i-i- ill ii i 1-I"t-_ c!!!1!,._"?'_." It---L-tI!_!!,, I II,11l,iit,i 11 I11111111 _l_ld _J I Iit i !t11', 1 tl ]1 ":..i:--'-Ii;_[_if,i!_ 111 IIII',11111! iUi;l!!llll j_lllll,i II ! 1 It_ "l-_Ti-- - ' ' -it,1-1-'i'+:_!!!!!ll! lil l I _I_L_I I IIII !i I/ t I _ _J2i21_-_ I--
I I{ I lI 4 11 I i , i , L - 1 - - _H-_'.,!!!!!-u!:,!,l!!! !!_,-!:-I-ri!i !__,_!,! ,, !iijlilt Itt!1 !I_,_-H-,-H-_ °"]"[].] ....... :-- ....... 2.2.-£ ..] ....... :"; ........... :" ' ! i':i.-;_ c"!.......-,.......... X /.... _.................. I.... __11 "_
•-"1 " '. ................ _........ _-i-..."-.. "_ ......... | __-iJ';..'_i:'.i'-"_'" ¢- "_ I '-']- ............ • :" • ] - -- ' ] ' " i : " "........ ,,,. ii-:.'i , , ._,. ...... l--,.......-.:._..,,. ......:........ ._._.............. -....,.................... -,....,____•'" �.,-,L,,I .'_. , • "" '" .I _ _ I-:"'.'_"'.:-.,'1.':._.-_....--i_:=-": ::.: .... -.:.-.-i.i:1': :- .'-':. ".'.'.':: ".'.":_.. _ :u .... : :':..,..--" _.: :.'L.:'..'.:' :...,.:.: :.__'.'L.,.."".',,. -:_-"__1_ C
r.i..
_.'2._2,,.]'F-I+ i',.'I:_'.'"ili',." : ''.]'_ !'i. '. _l..'' .... :--'IT..._-. ...........--I ............. : '" • ' :I.""_.T4"l'ql ti"• ....... -'_"' ._ 14--_ .!: : ..... :'.. • ..... i;.,. .... : . . .,. :.. ................. _1_'t' i t!.,:---__"._ i'--,, .......... ::..1...... :-, :. : i. .,. . • • • :. ;: i;i1;I..._ 1 .,,-:,
F '.......:tl........-':t.....:_........t...............,4. it _-;. .. ..... .;---!.--- .:.. _.::: . .--.:. , ................... ;----:!_ -I-j["-.,",_ " '::" : "!-.'-7 7": 7: : 7: : : " ' : : ;-'.. " .................................. :- -.". - : "........ .............,.............,.. .... .... :,
L...........................:f..................! i'".............. i• " _........ ' ...... !/ "" '" .............................. _"'t:" :_t'- ...... "-'-" .............................. : _-- 'b_'-"
..... •.... _ ..';-:'4_ ........... : ............................... il ,_ '.I,L'" #
-" :: :;:!i"--?:: :: :--; _: .:_:] : ".:::--.: :i-::-::::: ":'.-::;_i _................,..............................'................... ..... .!!_._+........................_: ___,__.__.__,:,, __+_....______.........:__+..__+__.-' .=-1 '--..-._ ..... • _." ........ L=." . _ . =.-_.= & ..=_ , -- _ • .= ._.=.. _ ............. :-J=: : _ _,: • •._---. . : _:- , _ :..: : : l . . . " .... !" . . . ..
• . _ . _.--..._ ..= ........ ... : [_'-_ . "-:-_]. =...-..=.:._., .... ..... . I.I._: -w_._ . ._: :.---_-- .J .---------_-. • • • . ' . • , : -
.r ..... -._, ::...ll.-... ,,,..,.-,._,, :.._.,..._,_:..._-.:.l-.--._..::.:-l- :.._..._rj")
' 4. -- ..... "_'--':" ", "':" ! ........ ! • , ........ "_'.-",-. " ........ i --"-- .... -_:'_',-.'F--.--,--I-.......... #--.1:-- . -,- .... l_l].... •,1........... _';@ ..... , .-.'-.:-_ ......... _ .......... •......... 4" i:,. ,/ ........ , I; .... i .... !-I.'."-!P_,i!...1_ --..'-- _ '--'-- .... _------'-M- ------- .... : ............. , ...... " i'" • - • 1, -: ........ : ! £ /_- F[_l
• -4......." i i 't LII- ",,I...._._ .... " • ___:_._ I.'. ......... : :.... _ :__. ..... --: ._... .......... _ , .................. , ! , . • _ ..• ., _ ,! . , • . .. :::" . . .. • . • : ................... . ................................................. _..... _• • ' • • • • • • : ' : • "- , i'..
...............................................--.--J:._.._,.'.' --,'"I-........................--! '._\.............:-_;.::_'"t!""....._:• :..= ...... i ..... : ; .... ' " .... ': ' ........ --':' _ " "..'i__.':'.----,. 'l r ...... - " ., I ........ ,: ............... "......... : .......• • . • "'_.- ...... " .2.= ........ , ..... • ....... !__ i" ,_- Ii-'" / _ .'7-.. ,; . • ": .T • : i _ i " " , ',1" " : : : " ! :_": .... i : ".llltllltl_w.',,*. .t.r- ,, 0:
......."1-i r-,",.-1 ............:- '--"--'--"_-""-............".'""I""".........F..... ........""": 1 ....;........ "-7FT_'I_------i----;-_--"--_.,-:------i-.".... _ _..-I-_--'=-_-----_.... •.I • ------'----_ .......-<-'--.-----_....,.... _--+--_-.4-.r-i_..-_-..... __--: • ,-'-_'-.-r-_-.... " .--...... i--,-'._,...._+ -'-.'-.-......." ..... -'_ -!._...... .:....... r_.......; ....r_'...-4 --:.. _- , -+ /.-_.-,,i..... @ .---.-.--l-_.'_,-il-,-I-,--- ,---.-,-II_--I_-4-.-4-,..........:• :----.:I-.--14.... _---_-t-......-." :--,-,---_-..:..• ,-...._ "_
....... _ -.-i._.-_. ....... '----.--'--1t----.'i"44• ' ......... , , : , •--=1. ,-' !_- - -4--.J ........... ,- i .... i " .... .,-i-_•--'--.4.'; .-,i14.'_-.i _'_._:1. _i • ...i--_.4-."I:-,L:" ..-__--..-...-i.- ..... ' _._-_i'.." ....... :_..,_.L ............. :. ;.i-I-._ I..-" . . i." .... i., l.I
----:_a-i .__. :.---4-"-,-';."i-.--:.:. :.:,.:1[-,.,.. 2:,:_-::,.. _...., ,.. _,:_--...._.r--.-..,-,,i.,c...i-i....=_ _:',. 2,.. =.p.i-".. _--I.t..._-',.._. --_ - ." ..... -.i...:-.:..._-, -. - ..._-h--- ,.-.,,•i..... i...i.-.,-.;....... i-. _ ..._s_ll• i : I ." c,'_.. .... "1" d • 1 - ' • : .... i - . • i • • = il.i... 1.8 :/ .... i • • = - |/ : i_.-N _t'-t--i_.'." .... ..,-+...;:--.t-F_.':_ .--_.-_._'...... t--+..... _-_'-,-',-I'.'.... .'t....."."-'-+.+Pt....... ,-,...... _,.:_'ll_= " i :,1 "" w=---,,,.i- --'_-",l • " " • i...... "-i. =--.. . .-"- •r • . i .... .- i " i ' " , " '--
• "-I- - il'-"'_".ll"i-l- . a.. . _ --___ - ...... _ . • _. =,,r,--. I .,..i." •L.........
t; iI _ if ili iI _ tI _ it
>"i __ >' il
7O
1966018034-087
71
1966018034-088
°_ °_
+ - +. +_.................. ,.......... i___........... _+_, ,+._!%+-
....." --=_-=_....:-+'_++++.......+- i _I+ ...."O_
.... :-I+_-=+........:......+-+-.--_-_=+-_I-+......... i -- \ _+\_.:,_t____.:_j¢_4_:l
:.-:_.:. :: ...., ,..........:___......... __.......+_........_+..... ./...:,__....._,+____ À�À�t�”�::-L::::' e,......_-- :-.........................:l:-_ _I_ i ........ ' .... " .....(:_ _+-_+_,_t"............I: .,_°...............:.- _-:::-: -;::---.I::..:-::_:_.:.::_+_.+___:_____u_:.... ++: ---:.::- -:- _-_-::_L-:-::.-::.:2- :.+--_:::+:I::...... :_.......... _ ......_-,21-_...._:_--,+_---++-:_ _
I :i I ".... :............ . ...........................++__,+.I,.,if___+- ,_-_-,tl"+ -- , . ' , .' .',+_'t______ _..... ,+ r--I
0(13
------:-.-_-+.... _._+-+_<--_-:;_ ,_.,,i++,_+.+,,_+_14+Ill;+ _I++_
_._________......................._':-__++ __+__I__.__+_ ,_______I__++___ +.......+--K+G__.__++ _;_J
, . _ _,, ' + .... . _ .._____ ' .+_:_ . + . _,l !tl_i I -+-+--+-.+.-, ELI
,=.+-_ ,:_.. ',_ _ _+__u__-_ .,_.u_u_...... J.... _-"':' {!ill-+'+; _ 0_-P4-1-_-_-L ..... J-_;---'-_--_+li-+ _=- .--_H--.' -_-T --_---: - :- : I - _....... I--'+ - �--T---PT .i O O, _. _ . . ,- ;_-- .,.._L--_H-.' ,- ........... _ ..... ;]+=:+ -+-_+-_-_ oH.-_ ,. +; __:__++_=.,+__.,+__+_--_-_I-L_I:......,....__-_._ ,,
-, i +1':, i ..... :-+-r:J-_-_." ., ,; . ....... '-. ,I-_- - _+._t -, _t. _ , +-++PH.L.:.,-'_ .,+ _, ;. , ! , . _...... ',_+,!_ _ .u,_ _=,+ - _-r+,, IH--LL---L-'-P-,--I.+_+'---: - + ;+ --T_-:_T, 't -Ii:!lt+ ' ' +-'-T':--.....] .... : /,-i ,' ll_,' +--i',_-{H'- ' , . _ ...... +_-_-_--H.--_ __- ..... +-- _---_ _-_- -PPP++--_ _-[+,_'L-S 0J r/_.---_ + _-_:-+._----T_-m, ,---, +-, _ . -_ ,--, ---_...... _ , ,--_--_r, -+--P--f --i- _ - -I_
. t,, ...... __m _"i_+':"_+l."." " :-+-I-:-_. +--_:,--: +, ,+ _++++-.., !-t .._m+'_:.+........ ................... ', _u_ [+ !+,O 0.)
: _1 I I I l_-! ! ; I I l I ! . ' I . _+ , -_ _I_._L..____A__........... i+_-,++-+--+-+.- ' ' 0..)_ _ _._ t ; i J _} _ : ' ' t , +I!+ : +: --___L -- ' .._ _'lu_ .... L_._.---., ' " - +--:'--:-+u-q-_--+ - [_,---T- ....
+_f ...... .,..., --= . ._- t I+'..---U-L-,- ' ++' -+' _ ........ ' ..... _.- +-+-+-+4-._ -+"_++__++-_+,,,-,.,- ., ., +. ,+,.+ _++,__,_ ..... _+__ -----' .
_._......... , ,.--:_-+-.--_ .............. -_-,---++ , +, ,_ _ + +_.+_T'-_ '-+-"" 0..)• ' _:-_-- ,_-++''_ ' +,' _ ---._----+--+Lt----'-': -+.----+-I:_-_- +-_-_ _ ___U+__+_.+__+ ' ' ' :L_J-- . + ,_-+-T_+.t _ +- , ' ' - ' , '' _ , + _ ' ' i I i : + + , t +-_+-
.__+.___,,.._++..L_+++. __+_+++,__+. l�´!´�4,_+,___.___+__+.+_+_+.___..+_+:g_,+,+_+,._ ,-+., . :, ' ; ' ":,'. + ...,_+ , , = .'" .:;I , t [::
__+_++ ....,__:......+ ........... +++:++++:+_++_-- . • _.:-_ _+_ + : _.__+.____.+__. , ' '+__ __ '+_++__L _ ..-_-_4 + .... -_- i-+;...... :- .... _ ........ "-I-+ u-- +-+'_ ........... + - - -_+'- "+_--"+T- _ ..... +-++- _+_+,..+__ 14\
,. _-_,___ ....... ::_,_ J+LU._' , ........ _LI. - -_=+-+4_-+-_-+--;-+----.._-'_........ I ........................ -r=-ILT: '.-:_----]-FFF_][TFFFT- ...... : " I "+ +--7-m,--t-+l-_-: :: .... r-+ _-VTT--T ......................................... , ...... -+-+-'+ _-r ........ _ 1"7_+! : "+-_ [:_-_ .H' + , , + -- , , + _ + ' I ++ --+
..... I ..... :-_+-=:..; ........ -r_ .,-:r_wm-_---:. +- ;_+:--_P_.t-:q---:-:-t-;: i --+_,_:.i_"'-'-
" ++ + ++ ]++ + +
T2
1966018034-089
%5
1966018034-090
1966018034-091
AFTERSWffCHOVERI
|.l_j I: p I..4_ :,.;. i ": , "i • ! i .... ; ..... : ..... !" : .... i :....... :"-'J,..," ,i, i : ..... ;. t ' ,,-' , , ' ...... "L | I,L' • -" .......... 'C'_,YAwmox r_-';L:,;....... :t, ....... , ............... i,|_i_i,li:l!;m_1 1 = t
THRUSTVALVES ::"I'+ [="_ • ":i "'.= ' + : pIL., , _I - ll.h I.=-.| _i.' _I, _....... .I I ," ; ' = 4CCW.... ;'-b' "'!........ I,' ...... i il:.i,i.l+ I, ,. t, I i '........ : ....... i ........ J + _r + + _ ; +.. hONE
I , m:, ),i,_-_l _ K__III, a!L.,IL .. I _.
+,'J':....":ji..:= "+!,. :: ,_,,,,++,,:,j=,:....+. . . ..............,,! .... I!
.,': .....:.: :. r'..::.].!..:... ........ , ..... :;,. ,:,:'i..... ' , ...... : ...... = ..... =....... '--'. .. '--ji.-.:.--"..'.. :--i ...... =I ..... , • :...: - :.......
,..': ; :'. : ...';,..: ..... + ................ "i• ' • " ........ '.':":. :': i ..... ::%'_-'-..... ;...... • .... • i":1• "1 I" '..... i" " i .... . ...... ..... .....
Ii = l':'!';" ...... I....... 1 .-. .I.._ =._,.__ .......... _., ,. I ..... _ • " 'jP"'P"i"! "'I....;""._.....i., ....... ,. ,. + ;.- • ,-.i i.= '. • i_:-.l ".-.. ! _., , ........i"-i'= -=-_'-.'}'=.'3 -. w• i" ". • =' "; "I • " = = ........ I........ = .' • ='"L!;:_=-,. _:.;, ::..i,............"............... -'.. '. : . ., ..... ', ." " : • "
,=., ,I,. =.=i. ,' .., ..+:. .: .... ; .. .......... :.., . . ; .. ,., , ..... :..
I i I5V _i_ "" '.... 1" I' I..,|i i ": "q .... I .'" : : ....... i " " : "''." .... =..... ' .... '" " "
....._- .i-.-._,.t-,=i..,._..-...-4..... :........... i " ...."........ ; • = - ,,,,,-3,...i-..'l..r.i_-=...l.-i....J...... "-" ...... .-i-, . .... t , + : ...... :.... :._'!_-,,,, ' .....,.,J.... ;........ '_..=!.:.,. l.: .. ; ; , ' •.... .i...... ; ,_ .... , . ","
YAW POSITION iil-i ;ii........,,i..-_. ,....i,-I,i ,Ii ' • .:. ....... ," , ....... " ' , :........................ _ 15 BEG/VOLT e.- _ .'..= ' I .:.:. "._::.i. " " ' I ' " ' ---- - H_+'='T, ; I , i,.=" ,""=;" i "P,r" I "%, • "" " ".'.].ir- • -'" " ," ' • • " ' ............. =_,(.GYI_ IEItOI_ .','1,=h-, :'4. =..... ,J _ 4"_:........ :'i,,,,=. ..... _ + ...... _ ..... _ , •
I_=1TM "P.'-'I": r:.-.l::_"..""-,:'." ! ;' " ! ,"-"_..&_ / [ ............ i- ...................... I_";IF_ " ' ,,'.i.V , ..--,I.+,I.-' " "_ ' ' _ ...... • • . ." .' . '. -- , " '
... .p .., _ . : : . .i .. • .. , i - -....... • ......... . .... ,....I_:.I.,..i..... !-.,_ ._.,i.--_;......i.-.+ ;..... • • ..= =...; . , ..... . =- ,,li'fii,,,.h..:.tilb, ,=;.w_i+:i=i=l_=.l. =. ,..#...i .t=_ --:._.: .. ,. • . ;. .. , .. ,=i- ... ,' ; ., ': '.. " . . . "..._ " . ..... I
Isv_"'-'i......... ":.. ".............................................................................. ' .'
_+_+.'_i...+.._+.._!:;_l..:,i._:.,..., '.-......:..... _.,-,--.:.-.+-._+=-.'.......... ; • : .. ;. i..+:.,.P,,,.i..+_',_-P..._f:I'.:_,......,................. , - , .': P.....-"................... .+..'.!I,ie ,T , ' •. ,__ : • , • . ' •, " ." ' I *" ...... I" +'' "+"""_"-' =''.._. - _ ...... : ; I i0 3 _EG/sEc/vOLt,..... ...... , ....Y_T_ _':F..-L:'I-__,_ _.:rn_,._ • _ ....... _ ................ ;--.. --
,._('',I"""': '_'- , p...._i_.=1_I_,_1..."' .'.':;I"I"" ' ' ; "i' ' :. : - ! ' '... . : = = -. '.. I "" " '.............i
_-__..-.+" i.-:;r--._-..+.•.......i .... : - .,.' ...:...... ...... , ........ ,...ir,i,,=...,..-"l-'.#.- -.:_=_.'-¢;,d'_,-I.--'.l._..- .'_ .'=. t............. ,,; • : ..... '. • -Il_'d; . - _"_ ".. "'_:';;'E...':-t,i_.:_ ;'h-...--J'-.'+..: • :-_' = • ....... + ." ......... _ .............
n,, II_.,.. r. i .....".I .,I .iL-".",-dl-'l if=i'_r" -. "" .!.....:.."...:..,. : .. ". . , • • !............................. I" , Ii ,t,. . ' • . I , I I
' I ' ' . J ' AFTERSWffCHOVEROV_...i -I,:.?._T :::-.i..-,..r.="r' !."' ,i ':"..":": "'". i" ; "" : .......... . .... , •
' THRUSTPgrCNHIGH $5_VALVES I"1-! _"ir't'"l='_"P'='":"l ,,.I,, i I " _ ":":.-:_'-':";" :.... I !i ii!!l,! :' "! '!i:" ' " " " = " "" _,]!_!
, E
!:: :,,,--,r'----;--! , : ,.; ; ..... :::
,ri";!ii,'i;-"l_:-+ l'_.i,_l_...'il:.':.iE':h.":+l_41b'l":: ;',lu ' ",....... "....... P' ........ ": " = = • ,r_c.lmsrnom Eg._,,it,_,.,i,:=.,..=.,i,.li..i_'.:;.:;_l._,.t.-,.'..t.l_i_7_=:..;i.."_._.1,..._.. • , ". ""i ....... " .............. : • • . ; '15 DFG/VOLT
.......... I..I . . . t--.... _ • • --'_ __(_ ElllOl_ _1!.:'I.'1: ": " =" :"="P-"_- "" "-'1 "-m;,i:.':i".il._ =" !==E ...... _ .... _ ...... " - " •
....... .....+: ....!+;..........++_.,.._.-.t-'t_:"=i++:,..";.+_"+._, .'."'". .... : .............. :....... - .............._'I ....... _.'.:'..-.:-. -_-_.'_'_'::_d: ;_ :"":.._...,. ". ............. _ ...... I _ . ,._ r, .ill _ =...:.;.,il.=-.._=....i,,_i=..I _ ,, • , • "_ .... .
0V i " - .................. . ............ i .; : I • i.. .. , . . Ii
Sv _ --I-:- 7"T":":;_iid":. _i_'_":.'.,.-,,'_.::r.".;i.p._,.,i,_.',-;=_.....j ......... ;i-_'""-_ .... ' ............... "=
q , : 'rJ ..... :=i u_""';""" • .................... _' _" _"-_',-_"_ ...... ,-i.." .......++,....+,,., ,,,.,+:, ,_ _.... ,+,• . : .= . . ..... • I"I : :. . i : .i .i ' '. • " _" !| :-P " • i :: = " ": "'"l i . . ,. "l
I :.1""11;_'!i,_'... _" ,#.__, .'._:':_'-..1".......+--.i.....I":L'":;i.'I:'._..+-.,.........-r '-"" .:, .'. • """ I+,!PIo_DtC,/S_C/VOI.I"i;:__ !:_:@_iiE,,=.,_ -_+_ -,.,:,i---r,r-._i .........+_ _++:E:;'i:_,-<_+7--,=,,:.-: -.... P= "-PITCHRATE "" • "", ....................... .:............... I "" " " 'I; ...... _...... =" ;__.." "=' .:_fi ! I_ FlY C:..;'-I..,I "'; ";-"::t:.... :=.L:il_.j_= _:.:...... _, ' ' ._¢_._=-.4.=,, .. • ". ...'.".,..=..._:=F-=I,..I:........... _ ""_,, ,+...-.,...........i--"=;,;,_+1•i:: , . . ,;, . , +,. .. .n . . .-3_ "..[_..._=.=.• ' " ._ -T...TI"'r- • • • • "-:.• =++ .....+,+.
i I "'" _" " r • .......... b.+=_ "l.:m• -1 '_.'- _li .. ,ii" _,.,._:.'r.i_;p..:,l! .... i I.',. "_'i,.,.'_.. , "...... "=_...... ' .....,., .., ........OV _" .,. , J,=.". .". ". "" • i . • ....... , .+ ,_ ••__....c_L;; .i ' • • I .... "7'..T,.;._• ,
•, .= ",. ' • , ', , ' , , i , , "" ,.,. -i:_11_, ' i "I
Sv _]"l___,_l_.',m <'-.d.:"4.-i.: T"i';_._'__-'_+_::'i_"l '_t4 ==2'......................... ;.'.,';., . , :. , . ";:,,.=e+.-.=l=,.,ii¢,+:.-r,=i,+._.ie_:.=..,=,,,...!........
• •
PROGRAMPOSITION ",,. ,_ ,, .. i
I;dtl1='Uh,
,.:+,,,...., : , ,,:y;:_;, ,, ...........
Note: ,eMpmmlmete In IIMar rOql41near null C2.5V
See +IppendixVI foeTelemetP/Collbratlcm Dato
Figure 37. FAC_ _mneuver Characteristics for Acceleration = 3.6deg/sec _ (Three-Axis Simulator Run _i Continued)
1966018034-092
Table 6
i¢_R PARAMETERS
FROM THREE-AXIS SIMD_LATOR TESTS
FOR 75 DEGREE. YAW MANEUVER
Maximum Maximum
High Thrust Maneuver Lag Vehicle RefAcceleration Time Angle Rate Run
(Deg/Sec2 ) Configuration (Sec) (De_) (De_/Sec) No___t.
i.4 I 24.0 > 45 i0.6 40
i. 4 I 2]..4 36 8.6 47
1.9 T 15.0 33 8.2 48
3.O Z Z5.2 33 7.5 49
3.6 I 15.6 33 7.0 51
i. 4 IV 21.9 46 9°5 45
'_ 3.6 IV z6.6 32 8.z 4z
FOR 20 DEGREE PITCH MANEUVER
i.4 I - 12 6.5 40
i.4 I - 13 4.4 47
i.9 T - Z2 5.9 48
3.0 I - 12 5o9 49
3.6 I - 10.5 5.9 51
76
1966018034-093
parameter is very sensitive to acceleration variation when operating at low
levels of acceleration.
Fmneuver time zs essentially the same at all acceleration levels
except when overshoot occurs. Thus the runs at _ = 1.4 deg/sec 2 show an in-C
crease of = to 9 seconds in 75° maneuver time. As noted, thls condition does
not result in premature enabling of the SACS.
4.5.3 ACQUISITION EVALUATION
The process of acqumsition is considered to start at the end of
an IACS maneuver when the pitch and yaw position gyro error signals have been
reduced to a value lower than that established by the SACS-enable level de-
tector. When this condition exists for one second, torque loop closure is
initiated.
The acquisition sequence typically requires removal of large
(0.4° to 4.0°) line-of-sight errors. This is accomplished by torquing the posi-
tion gyros toward the target and thus producing high-thrust jet action as the
vehicle follows. When the position gyro errors are again reduced to a low
" value for one second, switchover to the low-tkrust jets occurs and the fine-
pointing limit cycle is established.
When acquisition zs accomplished smoothly, valve changeover oc-
curs only once without subsequent dropout and repeat. For this type of action,
body rates established by IACS high-thrust jet control must be low enough so
that the low-thrust jets can slow the vehicle without overshoot beyond the
SACS-enable detector level.
Thus most runs were made using a combination of high acceleration
settings for the high-thrust jets and low acceleration settir_s for the low-
thrust jets. After satisfactory acquisition was shown for this "worst case"
combination, acquisition behavior was evaluated over the range G = 1.4 to 3.6
sec2 /sec2. cdeg/ and Gf = .04 to 0.18 deg
Mixing ratio (KM) also influences acquisition. This is the ratio
. of gyro error signal to sensor error signal maintained by the SACS torqui_
loop. For a given sensor line-of-sight error, higher values of KM result in
77
1966018034-094
I
larger position gyro error signals. This tends to produce heavier high-thrust
valve action. It is possible to raise KM to a level where acquisition canno+
occur, or to reduce EM so low that acquisition times are too long. A range of
KM from 2.0 to 4.0 was examined.
The setting of the SACS-enable level detector also influences ac-
quisition. Position gyro errors must be greater than this level to produce
high-t_ust valve action. Thus it is possib±e to set this level so high that,
for a given KM, no high-thrust valve action occurs and thus acquisition is
i slowed. The detector level can be reduced so low that the time available for
removal of rates by the low-thrust valves is too sh,_rt and excessive repetition
i of switchover occurs, which also slows acquisition.
4•5•3.1 INITIAL EVALUATION
Early tests indicated that satisfactory acquisition could be
achieved for KM= 2.0 and with the SACS-enable level detector at 0.4°• However,
i a difference in acquisition behavior between pitch and yaw was observed with yawt
exhibiting a more os?illatory tendancy. Although gravity effects sometimes af-ifected pitch, it was established that this did not explain the differences in& .
behavior. Test records showed higher residual rates in yaw at switchover. An
interchange of pitch and yaw rate gyros resulted in transfer of the effect and
thus established rate gyro performance as the cause°
The rate gyros used in the FACS breadboard had been used for lab-
oratory checkout and in flight. To determine whethe_• the yaw rate gyro had be-
come defective, the rate gyros were tested on a single-axis simulator• The sim-
ulator was driven so as to apply step changes in rate input to the gyros. All
three gyros exhibited satisfactory performance for large signals• (This was to
be expected since maneuver control of the FACS had been satisfactory.) However,
at lower rates corresponding to levels characteristic of target acquisition,
the yaw gyro showed a sluggish response. _igure 38 shows the comparative be-
havior of pitch and yaw rate gyros at 0.2 deg/sec; Figure 39 is similar, but
at O.1 deg/sec. They show that the ya_ gyro response to a step change is much
slower and that its output amplitude is reduced.
78
1966018034-095
79
1966018034-096
"1g661_1ANA_-Nq7
The roll rate g_rrowas als_ checked and appeared comparable to
the pitch rate gyro. A similar satisfactory check was obtained with three rate
gyros obtained GFE from GSFC. One of these gyros was _ued to replace the de-
receive yaw rate gyro.
Subsequent FACS tests on the three-axis simulator verified that
the deficiency in acquisition was corrected by replacement of the yaw rate
gyrc.
4.5.3 •2 ACQUISITION _ALUATION RUNS
The effect of parameter changes on acquisition was somewhat dif-
ficult to quantitize. The time required for acquisition and the number of
switchovers accom!mnyin4_ acquisition were employed as indicators. The l_ne-of-
sight error existing at the time of torque loop closure was not detenninable o
Random variations in this quantity were sufficient to produce a similar random
variation in acquisition performance. Nevertheless, by observation of several
. acquisitions, the effect of a given parameter change was sufficiently discern-
able to permit selection of appropriate settings.
•. The line-of-sight error was never greater than i°0°. This was
because the geometrical relationship of solar source collim_ted beam width and
sen_or distance-from-ball required a pointing error of less than !.0° if the
sensor was to be ill1_minated by the source,
Each simulator run involved four scquisitions. 0ccasienal]y, due
to an improper initial alignment condition 3 the line-of-sight error at torque
loop closure after the first 75° yaw maneuver was greater than 1.0° and the
sensor was therefore not illuminated. In these cases the vehicle was moved un-
til the sensor ente1"ed the collimated beam and normal acquisition followed.
_ 4.5.3-3 EFFECT OF MIXING RATIO ON ACQUISITION
Mixing ratio was varied from o.0 to 4°0 for Configurations I and
IV. Table 7 summarizes the result. For ease of presentation, an average time
. for _he four acquisitions of each run is shown. (The average neglects the first
acquisition in those cases where a manual assist was necessary. ) Also, the
81
!
1966018084-098
Tsbie 7
_c_ oFI_z_o RATIOOnACQUISIT_0_
(_c = 3.6 deg/sec2' _F = .b6 deg/sec 2, SACS-Enable Detector at 0.4 °
AverageAcquisition Average
Time Ntumber of
Config. KM (Sec) Changeovers Ref. Run
Yaw Pitch Yaw Pitch
2 5.8 4.9 ]-3 .I..0 35
3 6.6 4.9 1.7 1.2 37
4 6.5 6.8 i 2.o 2.7 36..... i
IV 2 7.3 6.4 1.2 1.5 b?_
3 5-7 6.0 1.5 io5 43
4 3.5 4•5 7•0 1.3 42
number of switchovers is averaged. It is, of course, not possible to produce
a fractional switchover; nevertheless, the averaged value does provide an indi-
cator of the stability of acquisition.
The averaged data show that Configuration IV is more suited to
operation at higher mixing ratios than is Configuration I. Configuration I
produced fastest acquisitions with minimum changeover when KM= 2. The advan-
tage of higher mixing ratios with Configuration had been shown during analog
computer studies. Although the simulator tests confirmed this (Configuration IV
showed best performance at _I= 4), the seleczion between Configurations I and
Iv was based on both operating at KM = 2. The decision to avoid use of higher
mixing ratios took cognizance of the fact that mixing ratio is dependent upon
the sensitivity of the solar sensor• Some uncertainty is expected to exist
prior to flight. If the actual sensitivity is greater than predicted, the ef-
fect is equivalent to an increase in mixing ratio. Thus a mixing ratio of KM =
• 2 was selected. Both configurations produce acceptable acquisition at this
setting and both make acquisition even if mixing ratio is doubled.
82
1966018034-099
h.5.3- 4 E__VFE,CT $,F._L DETEC%_DR ON ACQUISITION
SACS-euable level detector seltir_s of 0.3° and 0.4° were ex-
amined. Little difference in acouisition behavior results from so ._i! a,O
change in detector level. A setting of 0.,[ was selected on the basis of pro-
vidir_ a margin of safety in the event of ou_-of-to!erance perfo_nance of rate
gyros or low thrust jets.
4.5.3-5 EFFECT OF CONTROL ACCELERATION ON ACQUISITION
#x_ter selection of Configu!-ation I as the preferred coz_figuration
(see Section _'._-5),satisfactory acquisition was demonstrated over the expected
range of _'_:lgrl-_D_rus_"'" _ acceleration = presents(_c 1.4 to 3.6 deglsec2j. Tabl_ 8
a summ_ry of avaraged acquisition data. Also shown is the effect of low-thrust
acce!eration_ _F"
Figures 40, 41_ and 42 show a series of yaw acquisitions from sim-
ulator runs _mde at _ = 1.9, %.0, and 3.6 deg/sec 2 _ respectively. _lese runc
records show position gyro a .d sensor signals; both high- and low-thrust jet
action, and torque loop closure and torquer action. The _ans were made wi*.h
CZF = 0.3_2 deg/sec 2,
Figure 43 is a similar record showing yaw acquisition with _F
rsduced to 0.06 deg/sec 2.
This testing demonstrated satisfactory acquisition Ferformance
from Configu_-ation I with principal parameters varied over the following range:
Mixing Ratio - 2.0 to 4.0
SACS-Enable Level Detector - 0.3 to 0.4°
Low Thrust Valve Switching Threshold - 5.0 to 22.5 arc sec
High Thrust Acceleration - 1.4 to 3.6 deg/sec 2
Low Thrust Acceleration - 0.06 to 0.12 deg/sec 2
The parsmleter values selected for the prototype FACS were:
Mixing Ratio - 2.0
SACS-Enable Level Detector - 0.4°
83
1966018034-100
Table 8
E,.-m_'rmOF ACCELERATION ON ACQUISITIOI,_FROM THREE-AXIS SIMULATOR TESTS
Configuration I
_.mx_ng Ratio = 2
oACS-Enao_e Detector at 0.4°
Variation - _o_-_ru_Z Acceleration
- _+"_.... 22.5 arc(_w-Thrust uet Sw......_ng at + seconds)
Cont ru! Ave rage Ave rage#cceleraticn Acquisition Number of Reference
(Deg/Sec2) Time (Sec) Changeovers Run
High Low_-_,_us_ Thrust Yaw Pitch Yaw Pitch
I.4 .12 4.3 4.3 1.0 1.0 47
_.9 .i2 2.8 3.2 1.0 i.0 48
3.0 .!2 3.1 3.4 1.0 i.2 49
5.6 .12 6.9 4.6 1.2 1.O 50
Variation - Low Thrust Acceleration
(Low-Thrust Jet Switching at + i0 arc seconds)
Control Ave rage Ave rageAcceleration Acquisition Number of Reference
(Deg/Sec2) Time (Sec) Changeovers Run
High LowThrust Thrust Yaw Pitch Yaw Pitch
3.6 .,2 3.2 5.8 z.e z.o 5l
3.6 .06 5.1 5.8 1.0 1,0 52
84
1966018034-101
YAW _ _GI_ _ YAW_ • C_ _ Ot_._qltlMANEINEI
Figure 40. FACS Acquisition Characteristics for _c = 1.9 deg/sec 2(Three-Axis Simulator Run 40)
8_
ii,
1966018034-] 02
86
1966018034-103
I+-'_CF-_---_-T-,_X:Z _ _J-9++__i-+-H-Pt-
, r, , T, , --_ , +7 _ -q _l I I = I t I t l/
+_-+__ _ 'i+ _----_1__ __'_---_---c_ ' q-_+' +__JN_OI -YAV+
-7"-!.... ,_-- ...... t _ ]---T--_ ._j _____ 0.13 DEG/VOLT
::_:_____-_ -::: :: _+___-+++___+_tGTlq
',-I-+'--_ --+-_ ":--- +_- ........ _'--- T
Y,,_V IO_QILIBI .......... --+--- ____.---:.--_ +--++--;--_ '__ : .... .:_u__u____ + '_-_,-++--'-_
v_,,,_mo,,, __ +-+-P+_-+-'-H- ,_------,_- .... +--'-' -+-' , * -+ ,-+_ ._ , _ i _ ____ l ' ' _ -
-: ,_ _ .._ __+--.p_+_ _,,_o,,,+ d
-+- _+: ;t...,,_,,--_ • ,+ . lfr.O_
I".... ' -- =..p_.L----t"- " " J + i • ' 1
_, .++,+++-i-+., "'-"4.:.-i - :',-;--+-:'"'-=_"'=_-_"+"-,+-+-'_-.T_.--..__ _.:..." " .... .,,.o+L-t..-+:i-t--]. L,.,., , ,._ +,_-uT+._ ,,_.
YAW _ D_QIIEEMA/dlEUVl_ YAW CW& CCW 30 DEGREe.MANEUVEII
Figure 42. FACS Acquisition Charar:teristics for _c = 3.6 deg/sec 2(Three-Axis Simu_l.atorRun _0)
87
i
1966018034-104
Figure t_3. FACS Acquisition Characteristics for Reduced _F(Three-Axis Simulator Run }2)
88
i
1966018034-105
4._.4 L_41T CYC_ EVALUATION
Du_ing testing on the three-axis simulator, attention was di-
rected primarily to evaluation of the on-target limit cycle control established
by the SACS circuits operating on signals from the solar sensor° The program-
mer sequence did, however, permit observation of IACS limit cycle characteris-
tics after the final yaw maneuver°
4.5._I.i IACS LIMIT CYCLE
The IACS l_nit cycle is established by the IACS control circuits
operating on signals provided by the position and rate gyros° The limit cycle
characteristics are sensitive to rate gain and to the accelerat,ion produced by
the high-thrust reaction jets° A suitable value for pitch and yaw low rate gain
(KR = 1.25 sec) had been established by analog contputer studies and was retained
throughout testing of Configuration I on the simulator. Also, the switching
threshold was set at + 0.25° and was not changed.
: The following tabulation indicates _he effect of yaw high thrust
acceleration (Jc) on the IACS limit cycle period. It sho_ild be noted that the
limit cycle periods shown are cnly general?y indicative of performance° Irreg-
ularities in the l_nit cycle make a precise determination _rzfeasible. Ti_±smay
be seen by observation of the high-thrust jet action shown during program po-
sition ii in Figures 33 and 37 In the former figure_ for _ = lok deg/sec 2o .CI
the yaw high-thrust jet action shows a point at which an external disturbance
was required to excite a iLmit, cycle.
IACS L_iIT CYCLE CHARACTERISTIC
High T_ust Yaw LimitRef Acceleration - Cycle Period -
Run No, Deg/Sec 2 Seconds
47 1.4 8
48 1 °9 8
49 3.0 6
51 3.6 4
89
1966018034-106
Control acceleration levels in the roll channel were set to 7o0
deg/sec 2 for most runs, with a few runs made at 1.0 deg/sec2o Three-axis sim-
ulator run 51 was conducted at 7.0 deg/sec 2 with rate gain ER = 0.88 seco The
limit cycle period in roll was observed to be appro_rimately 2°0 seconds_ Un o
fortunately, the runs made with the lo_er roll acceleration level (i.0 deg/sec 2)
exhibited roll unbalance which prevented determination of the characteristic
limit cycle.
When operated with the Aer_Oee 150-].50A, the IACS control acceler-
ation is dependent upon the pressure of zesidual helium in the vehicle tanks°
The system is operated in a blowdown fashion and a gradually decreasing thrust
level results from gas usage. The intent of testing here was to show satisfac-
tory limit cycle behavior over the anticipated range of acceleration level°
4°5.4.2 SACS LIMIT CYCLE
Tests were conducted to evaluate tlhe SACS limit cycle sensitivity
to variations in low-thrust acceleration and to valve-switching threshold level°t
The effect of variations in derived rate gain was not examined° A suitable value
for the lead time consta:nt (0°6 second) '_hadbeen established by analog computer
studies and was used throughout the tests°
Acceleration levels were varied over a range of OoOh to 0.18 dec/2
sec . When operated in an Aerobee i50, the SACS reaction jet thrust level will
be fixed by use of a pneumatic regulator. The objective of testing here was to
establisL a preferred level° Acquisition was shown to be reliable over the in_
dicated range; the effect on limit cycle is discussed below.
The SACS valve-switching threshold level was varied over a range
from + 22.5.arc seconds down to + 5°0 arc seconds. The switching threshold cor-
responds to the angular error which will produce valve-control-trigger action
for zero body rate. When the limit cycle is established, the characteristic
body rates tend to produce jet t_rn-on at lower position errors.
Setting of threshold level for switching at a desired angular
error is dependent upon calibration of the solar sensor. The sensor character-
istic is in turn dependent upon the illumination level provided by the solar.-
soarce simulator. Prior to three-axis simulator tests, sensor calibrations had
9o
1966018034-107
been nmde using a photo-voltaic cell as a reference i_or source intensity. Tae
reference cell was utilized to establish the solar-source intensi_y at the GSFC
facility so as to provide a desiced solar sensor sensitivity of 5 my/arc second.
Autocolli_tor measurements during limit cycle indicate that the actual sensitiv-
ity was slightly higher near null. However, since all settings were made on the
basis of 5 my/arc second, this scale factor has been used for all data reduction
involved in the following diseu_sionso
The examination of the lowe_ amp3itude limit cycles is [e3atcJ to
the anticipated requirements of solar pointing experimenters. A taz-get goal
here is to maintain limit cycle amplitude within -_i0 arc seconds while holding
body rates belgw 5 arc second/second. The FACS tests demonstrated t_e capabil-
ity of producing the low-amplitude limit cycle_ However, body rates were signi-
ficantly higher than the desired 5 arc seconds/second.
Preliminary evaluation tests _ere conducted using a promising tech-
nique for approaching this goal proposed and implemented by GSFC. The technique
.herein referred to as "delayed feedback", represents a simple form of pulse-
width control. Results of these tests are discussed in Section L.5o8o The fol-
lowing discussion is concerned with limit cycle characteristics of the FACS with-
out delayed-feedback circuits incorporated.
L.5.L.2.1 SACS LIMIT CYCLE - CORRELATION OF SENSOR AND AUTOCOLLIMATOP
Figure _, showing data obtained from three--axis simulator run
40, is typical of the correspondance shown between the autocollimator tracking
signal and the output signal from the solar sensor° Close agreement is seen in
the transient behavior of the two signals. This quality of agreement lends con-
fidence as to the dynamic-tracking capability of the autocollimatoro There is_
however, an apparent small discrepancy between angular displacement as indicated
by sensor and autocollimator° _hat is, based on a sensor sensitivity of 5 my/arc
second, the angular displacement indicated by the sensor is greater by approxi-
mately 10% than the displacement indicated by the collimator. It appears quite
likely that (at least for this run) the sensor-source combination was such as to
produce a sensitlvity at the sensor output of _._ my/arc second when operating
near null.
91
1966018034-108
7°92
1966018034-109
J._- The sensor-suurce calibration data obtained orior to three-axis
simulator tests was achieved by measuring sensor output with line-of-sight er-
i__ rors of several arc minutes. The day-to-day setting of sot[rce intensity was
also subject to slig_hterror. Under these circumstances the correlation is
i considered quite good. Also, errors in the order of 10% do not seriously af-k
feet any of the findings from the simulator tests.
!I
I. J,_'_b '..,,.:.2.2 SACS LIMIT CYCLE DESCR_TION
[ Fortions of nine three-axis simulator tests h_ve been excerpted
to show the effect on limit cycle of variations in low-thr_t acceleration (%_)
&Figuxe 45 shows operation at a threshold setting of + 22.5 arc
_'/ seconds for _f = 0.18, 0.12, 0.08, and 0.04 deg/sec2. Clearly sh_nl is the _e-
duction in limit cycle,frequency, and increase in angalar displacemenD as el. is
_ reduced •- Figure 46 shows similar records for a threshold setting of _+i0ar_
_: seconds,and Figure 47 shows records obtained with a threshold of +9.0 arc
'_._ .. seconds.
A s_mary of results is shown in Table 9- T+ is seen that the
v_ amplitude of limit cycle was held satisfactorily low. The indicated vehicle
F rates represent the hig_hest values observed over a period of approximately 2_
_ seconds . In all cases examined they were higher than desirable for solar point-
ing. For example, Table 9 shows a maximum rate of 58 arc sec/sec with the thres-I"
hold at _+I0arc sec and _f 0.06 deg/sec 2= ; this _s an order of magnitude greater
than desired. Incorporation of delayed-feedback produced considerable improve-
:" mer.t as discussed in Section _.5.8 below.
Testing indicates that for operation without delayea feedback, a
"; low-thrust acceleration of 0.08 , 2deg/sec represents the best selection. This
value is low enough to provide reasonable limit cycle characteristics, and high
"]" enough to produce reliable acquisition. The tests demonstrate that limit cycle
amplitudes as low as *_9arc seconds can be achieved at this thrust level.
• 93
1966018034-110
" F = 0.18 DEG/'SEC2
_HREE-AXIS SIMULATOR R.UN 7./) 0'HR
rmc"-T'-T-" " -- --1_] ....... ---- I--FT F - " -t • 7-_.__-:_:_.-_.=_._---a_::J:.:-i t 1 t, t, I ,. ! '1 t ! :,-t _--Fl-,'! [:-FT I ::::i ":_b !"-t !]t ]:"i'..'_...I'i-'. "".......... _....... ; ............ : : ........... I " _'" • ; " [--_ _ :l-z" :-:t :'+"1=t ....71 _-i .I':::._L
" i";:i:: !"-_: :: " ........ T .... ; :: ; ...... : i-:-I } ! I:t.} :- I..I :L..........." " " ...................... " " " '--' ' _ ' " " I_lfl-I_::-__.__ __:i._! P t-_-iCW e_t_{._:li_lti_._.#_.a_f_Jj,:,.s-l,'l _ _.F_,t.O'_=t.iL.4:,,If_F_ "*k ..: ....:.."'._:-,' ...... , • • , • I i i _ h !-,_-I: -I : t :.:_
;_.'--;--1-t._;i i...-..=l ::.-.-J--i. l.., ........ ;.I i ..; _..i .... ; ..... _-_r,fll-tl:lI_l ,I-ik-llll:.l _._t_.k'i4_-_._,lLI _:,_-._i ,I | 14' r,. I, I: l_! a! t : _i'- -_...8! k, ! .I p! i : ....CCW _'!_:11-'|1_1TM I!'-;rl;,.:|!!..':l ,1: : !,! .-i, il, ::.1 :,_eit,l, I " _I__:i-.-:_-I_.llt_:Rt:I-IIt_i:t,J[-t_
"! " • ",_ " i-i-" , : -:i :---'-- ,_ i | r .... :--'-- r .... : • ,:" : .... it I_ • t .- • ::. , . _r, ,1I. . . .. . .. •
,.ll t:. I ,11 ,t , , _ .._..111_:',:_ -_., I'-'-.-:'. , : .... -, .... ,'." ", t. • ! . • •..-.-,...... -.'.[_-.,---_-.-..... I ...... . I......... , , , t ...... :. --.---_-.- Ul_t:-lg-'tl,tt_,_._[_:i:!;i!lIl_t:!lll
...... I!l ' "J " ' " !It t."t..' ,1"" " _ ' " i. i l_llt-:_ll_ll_lttftt IIIi llll!"rl -Itt?
,-i,-t--lU_--I:"l=ll..i'_.i..l.i|_il.l_.ll .lilll--ililli-&l-iliIil.ll.,.ll" it_.i.l.lll, li.. ,i ...... :--,. i L I j,,,I,._"..I._l;_,i_'il ",.._ ..... I _ I i I ',l', : . ; I". , , . : i i . i _ [_i_L__L.L..L_L ...... I._L_!__J
I':_'l,i"il"T '1 I r I_Jll i l I I t t I i I I I I _ I' !"i_' i,qov____l_ l_q?:ll :I I 1 i t V t--!.4 :--I_:!'._-_::t_;_:__.....:_,:,,,........ ,i,.....:....,, : I
].:....:.I..:.._T":'!:'='!:"-i:". "-"".....'"" "'_:"i ' ; • ' ' • : • ! -: : '"i" ,.. ! !. .... :.. i__. i... i ,. L_.:... |j: i:, i..... , i_ :t i' i- : i!' }-
........_,, ...... _,_,..:_ ..... .,.:--- .• "_ "'"i: i - -. i I : . .: . • : • : . : . : i : : •I-_,,,.,.,,.--,-t :-: .t--._; ---..-,-,'- _', if|...- -.-i _; ! ....i' :. .... - I i I i _ :i'-.... I.., ." ,.I, ... i., ...... i . i • . , : • : I . _ _ • l .
.l--,k-"r',":l'"r-'-,'-,,.i.',,-" _ 4-.- , .-.. ,.. __ _ --.'........ t_ : • - . l - I __1.4_i-i--'...............i:-'-k..,--_i-..4.-...?:i-...i--i i--.i..;_..: i.. _..i...i. _-," ,: _.",_"i i" i-i-,.. _ 1 -I _ t-i:1
sv_.:.,_:::_!::"-l:::L::.l-:::'._._.-':-i.-_: i--i , i .... ._"i :,_ ov ' •
1966018034-111
"F " 0.12 DEG/SEC2 eF = .08 DEG/SEC2
EE-AX:SSIMULATORRUN47) (THREE-AXISS1MUL_.T._ RUN21)
' i : i _ '--'_:-- F i i : : ",-'l_-.t._'_"i--] I._'-'T'--'T'--T'-T-T--r-"'-;---"F--I_ l--T " I --F-T- --'-T" • I"- T -'F- I"-r" I c --T---r ...... . _ • ! _ i " i : '."--. ,
• " _--' ' '--L.-:' '-- [_i__!_ir--::--l:.::_ i i. " " :,.: : "- ! .- • .......... ; : . ! : . : _ : •
--_' -....--'.. ,:_----:_ _ I-_--"-:;:_;- .[ ....... " : -....:.-...... .".......:......i -"" ':": .- : "."
!---T_- ._..--_'L-_-,."-'_--. _2]- : • :l: ,i _iil_.,.: ;I]_:rK " I'..iTTr';"_-"i i.,: [_ .... ! ' _- _-J: t - : --- . : . . : " _:.." _: " " . .'-" .t- - -, " ..." =. : . .__I. F":,l._ :hll El,i; i:.i t_!_ ;---_ " " " I _ " I " " _ : : .... ": " : I _ : i" "1 "{'I': '0" " _I-:I i'-:I _ .
• " • • _ " " " • 1", ",i .L[ [FF_ I ],J;la ! ' li_J RI-_ ILl _-Ii-!._'-] • ..... • :- :.._ ...........................I • .. : • : .ii: ; |'" " : • : " "" " : " • " • .i i :
.... ..... ' .........":I 'F i!-' !] :t!!;' ..........• • - "..: - .,__., '" " :._..| i ]i " !.: J .i ' ; _..._._.,._..__.L_L_I._±_J--J--- ' : ,ii " il '_ il_'jl i. ;,_'_ i:l .... _L--.t.L.,_......;.r::;''..".':
__,'J_,_U__L,____LL_L_L_LZi-I :-1! " ov_ ! !. !..I._L!/L_I-_7_.J.L i ;I]-FT7_.-]-T, L_ J_--_-! Ii., _ , , : _ . , , :-...-'-KT-___, . . _-,--r-: ! "": "' .":;_i ....... i.i-::--:----;.-.!i--'-..-!--'..;t:_.i.!-i--i---_ ---_-.----_--.--.--,---,-.- • - _ • ; ' • ._ ".'--'--...:-.-'••! : -"_ "i•!": • ":i--_-_---Pt'-_fi-t-__t-i-ff_-_,.---- _ _,_]..... :...: .... :, _ _ .,,., , , ; ;..,.....-_!-..;_..,...._.
--', -T"-_+'_.,, _---*..-"-_,---T-'H_:'_': .... .'---I"- .-:--.'T'_i---_ ............ : . : : : :-_- ; _ _-,---_-_---_---_-........-.-_--_-_,-P- _ .............. • t _ •" • _......"' "--'"i....i _'? :
:---i--f-'.' T-T,-_ ._-t----_--t---_-i,--_--i-- ------__F-_-_. --_-_:-_--!-_--_-,-_--_- ' ' : ;i'''' - ..... _
Note: 1. _ is low-thrustacceleration2 Yaw SemorOutput X10:1.0 VDC - 23 arcseconds3. Lng'Feedbacknot Installed
Figur_ 45. SACS Limit Cycle Characteristics for Switchir:g.Threshold + 22.5 Arc Seconds
1966018034-112
aF = .04 DEG/SEC2(i"HREE-AX}SSIMULATORRUN23)
....... IT-,---T-_,l-;T , , i ! ,_ _.......... -.................i,
' r" , r " r YAW LOWTHRUST
: _ VALVES!
' li /_. • •
..... :'11 ' ---_'-- i . .. . . . , , , .,,-ai m || . , ....
J
[ ..'T_'_F_'-r-, ,'-TT'rT T'-r'" r- _ '.- , ,-r--r-, '1 :"_,_,,i,_*:,l"r. | _I "'OV .: ..... ' -i--.l_-. _--4-. ..... "'_ ' '- ' . .._ -
' I
_,..._ OUTPUTX!O
ii l
$'Vl_._.___..................... .,............... '_ ;__ 'k.
: 94 ----_
i
1966018034-113
_,x
_ _o
9_
1966018034-114
. F " .o60EG/_
a F = 0.12 DEG/SEC2 (THREE-AXISSIMULATC
(THREE-AXISSIMULATORRUN57)Lr'.....,. i. ,,,"_-. -i "', _: :"_::. ""|:. I;..,[;,I': •[ , I.." ..Q_..!.......-.; ..: .i., ,....|: .,. :
..................... I .... _ h.."_'-'"", "" : ' "" ' :'". .........
.,_ "' : • " . .. i ....... i".'i i
i' j':': •! ..... •._.......:':'r'"r-. •
iI , .
-+ _.rl_t_.I.1tm,,.,:_,,.....
C'_ _ " ,._..," r'm: .. ;r ,'," " • , "...,,
• • " .it, • ":,..'rl I_.. i'_|,," 111..... ,.'. ,t. .. ..... .i
[_I'11:'l;il"" ,'-"4ii!'ll,t" .'fl'...m].-,!
• , _.i.__.fi,_,.,_ ,,._,,.la4_.+_ ,,i',!..,..,I,.,.k'_,_.,. ,,I,.F_4 i',:l;' _'::Pq " • 'u '..i "_, L" ..Sill-;',,.i' L,,.I,,..ll ,4 :i. ,_,'.k.'..,.i.,-,,;,,_,," 'NONE :.._ :.._
r-'- .... "I-"" • : _ • . :,. . ..I.. _...: 4.:. ,+ ',.',,.,..".'."'}. ,_ I_ .i-'::_.,,_::_+._-
" _ _: _ I l--g:=_..=:Tir:'"i"'_'"'L_:;7_-::7,:l_'l;,.d-., t ," ' "" - " - - r ] I
•. l;.ki..: :_I-',:;i':"+""........ ": :: :'" "' +"T'ov "":-'_'--" i:".,_"_':.,,:.'...'-.,_._.._....+..'._,-...:!!".."..':..._._'_, , "-"." "",, I " • ..... , : ...... -:_ :i: ..l.. ':"" • •
++..i+._-ri:,71, ___-i.. -:::'_.':l_i: '.._i_.l'-'_.i..-_:.-'
I,,illl._ I. "F h lt,,.-ihn.2. Yaw SiMor _u3. Lmlfesdl_k+
Figure 57. SACS Limit CyeThreshold +
1966018034-1'
,EC2 aF = .r_ _EG/$EC2)RRUN 8L_ (THREE-AXIS _'ATOR RUN_G)
_: _ . •...................................::=::,-: ,. , , ; _ .,_-.. ,. ._ ............__ _._ , - - ,- YAwLOW'm_UST
_1 ==================================
• • , ' , ' ' I I[ ' i 11'"¢" ""TITTTTTTTTTTflffIITt_'ITTI'TmIIITmMTl_Tl_TT_bqtTC_lTI'".',......'q" :....._"' ......:',.,"'......"'.--_'.'_.."""-- ov I_t!lt!i!trl!l_II!ltliilll]II!!tmti._._.,_,_ ___i_Iii_Ih_!1_1_!!_!
I Table 9
I SACS IIMIT CYCLE CHARACTERISTICS(Without Delayed-Feedback)
FROM THREE-AXIS SI_rCLATOR TESTS
iSwitching Low Max. Max.Threshold Thrust Peak-to-Peak Avg. Vehicle Ref.
t Level Acceleration Amplitude Period Rate Run
(arc sec) (deg/sec2) _(arc sec) (sec) (arc seclsec) No.
+ 22.5 .18 21 0.5 116 7J
.12 33 0.9 96 47
o 39 3.0 50O8 21
.o4 42 5.4 29 23
I + i0.0 .12 32 0.74 149 54
I .C 16 0°54 .58 52+ 9.0 .12 28 0.77 129 57
_ 08 17 O.55 77 8E@
.o4 12 o.53 L2
!
l, 97
I
1966018034-117
).9.5 CONFIGURATION COMPARISON
Simulator test findings resulted in selection of _ZCS Configura-
tion I for follow-on design. Altho1_h four configurations were checked, the
final seiecticn was based upon a comparison of Configurations I and IV. This
was because the differences between configurations were zo minor that each ex-
hibited closely similar performance° Therefcre the advantages of dual vs single
detector and single-level vs bi-leve! rate gain could be ascertained by a direct
comparison of Configurations I and IV.
As discussed in Section 4°5.2, the configuration change produced
11osignificanteffect on maneuver characteristics°
Inherently_ the configuration change produces no effect on SACS
limit cycle° Single level vs bi-level rate gain can influence the iACS limit
cycle but testing did not demonstrate a discernab!e difference°
As discussed in Section 4°5°3, the configuration change did in-
fluence acquisition behavior° Although bo_h e_hib_ted satisfactory behavior,
Co_figuration I was shown to be better suited to operation at low mixing ratio°
A comparison was made of vehicle body rate at the time of switchover to the low-
thrust jets. The following tab,_ation shows tD_e_esult of averaging this w lue
for four acquisitions:
Configuration I Configuration I¥
High Thrust Acceleration - deg/sec 2 3.6 1o4 3°5 io4
_xing Ratio 2.0 2.0 2°0 2°0
Body Rate at First Switchover - deg/sec 0°085 0°062 0o150 0.117
Ref. Runs 35 40 41 45
; Configuration I c_aracteristically produces the lowest rates at
changeovec° This attribute is advantageous for a smooth transition to SACS
operation.
98
1966018034-118
Although some component simplification would have been possible
by selection of Configuraticn IV_ the acquisition behavior of Configuration I
was judged sufficiently superior to warrant its selection.
4.5.6 FINAL CONFIGURATION SUMMARY
Simulator tests were conducted at various levels of high-thrust
acceleration for the selected Configuration I.
Maneuver characteristics have been shown in Figures 32 through 37.
Acquisltion characteristics have been shown in Figures 40_ 41, h2,
and 43.
SACS limit cycle characteristics nave been shown in Figures h5,
46 and 47.
Of the parameters and configuration features evaluated during sim-
ulator tests, the following selections were made:
a. Configuration I_ dual detector_ bi-level rate gain wasselected.
• b. Position signal limiting vas incorporated in the I_CS pitchand yaw channels.
c. Roll rate gain switching accomplished at roll capture andlocked thereafter.
d. IACS pitch and yaw rate gains set at 1.55 sec (high) and 1o25sec (low). Roll rate gain set at 1o54 sec (high) and 0.88see
e. _xing ratio set at 2.0.
f. SACS-enable detector set at 0.4°.
g. Low-thrust acceleration at 0.08 deg/sec 2 preferred unlessdelayed feedback incorporated.
h. SACS valve-switching threshold settings between 22.5 and 5°0arc seconds found scceptable; can be adjusted to suit missionrequirements•
99
1966018034-119
4,5.7 CORRELATION WITH ANALOG C@IPUTER STUDIES
Analog computer runs were made for the purpose of assessing the
degree of correlation with 3-axis simulator tests.
4.5.7. i MANEUVERCHAPACTERISTICS
Maneuver runs made on the analog computer show the sazlegeneral
characteristics as observed during 3-axis simulator tests, S_apie analog re-
cords for a 75° maneuver are shown ._nFigures 48 and 49 for high thrust accel-
eration levels of 1.4 and 3°6 deg/set 2, respectively. Sffzliiarrecords are
shown for a 20° maneuver in F .gures 50 and 51. (Note: The configt.L-ationand
parameter values applic'._b_eto each of the aDalog computer records reproduced
herein have been tabulated in the run index of Table i0. )
Table ii shows a tabulation of maneuver pa.rameter_ obtained from
analog records. This may be compared airectly with the similar tabulation for
3-axis simulator tests shown in Table 6. A comparisop will show that analog
results generally yield :
• Slightly shorter maneuver time_ TM
Lower values of maximum lag angle, _'Emax
• Slightly higher maximum vehicle rates, _max
To account for the differences_ the coz-respondence between the
two simulations with respect to several parameters which significantly affect
maneuver characteristics has been eLamined. The parameters considered signi-
ficant are high thrust acceleration_ (_c' gyro torquing rate, @C' and effective
rate gain, KRE. The time constants associated with the valves and amplifiers
, are thought to be sufficiently small to have negligible effects on _, _E '
and _max "
The effect of a difference in _ , alone, between the two simula-C
tions can be assessed from the results obtained. As _ increases from 1.4 deg/2 C
secto3.6deg/sec2," thetrendsof ,and¢maxcharacteristicallyvarymax
* It is recognized, however, that these t_e constants can have a significant
influence on impulse expended during maneuver (c.f. Reference l, Section _).
i00
1966018034-120
i'-"-l: i'..1:} ;-'"'"'...............' '""" " .......... _ " '......... ".i. i-,-.i.....-...i-,.-i-. ; ..i ........ ,.,,..,. .,,, ,i
Moo=sl l,i IVOTS I' :" ' ; -,-" "'........'I,T I'_;EENOTES) ._..... I ;": i:" _-. _'"',"'.'-;.''! ......... : ...........
Ii "" :'"'l" "_ ":'"'"' " I." : ": I ........ _ i....... r ................. : ..... I .......... .
0 ...... @ - " ' ' " I . " "I= " ' " I i. ; • : . . ; .' .ir'-" , .... _ .... 1-'"" ='"" : ......... i " " "" .... ..r.-:.=.--..,....:. • , ..... : .......... ili • i . ..- . : /
.... ,._.. 0.................................. :;.I . .. i "-' . ' i ' : I = • : = '" : • '
....... :..'-:--- .--..:.-- : "='--m e -"i. ,-- =- " = -.l ...... i-...t ..-=. _ .......... i• .......=. • i ._=
I-...... i............. " - =.-._...... =.-.--t--:---=-. ;..... _:-.--.-:.;_l-- ---, .........,,300 I ...... i =..!..... :." : " " " . =...."...... :..i,,_'. " ". J. ,i.." .._: .. ; ........... : .i. i '," i, "
I , ;,,_ =........................ , .I ....== ir"_-'"'--r-'_--"=• l . i . i_"1./ .... I ii...... ..; - "l..: -=._.;..... .' ....... .; ...... . .
, : "" • . . ! . : .... :....= .._. , I': , ' , I" : , .,F ....... = , ..... , ...,r...... t-.i ..... I _=- I-+--,.-.'=..-.-I_.-,. ..... =.-=..= ' .'.-=- ........ , .............. '
" I . . i .. • ". I. " "'i ." :." " :. : .... "' I
(U_) l-t'":..... :::.:"-.'--'"""'=::'_'..""--_.=-'--'.'""b"L'_""'/.# "''-'........ """,..-.;.... I...i":"--'--_.;-_..'=:";.:i'--i- '_";i=';"""_--,'."-!.'-!:"..'--_.•:'_--,..i; -i-...-_
0 I " ' ". ' .- ...... :'"..:,=._:,..'. i.. i._.=._!.li=.._i.:.;...i--:4. ; ,i....i. " " "" :...... ,• = ! ! .I. " .rr. i":'-'..-i.'g :'" = • " -i ', .." ..i : .. = , ;! "." "i I . "=..--I ...... -.r--_----.-._.,- .,. ,........ ,....---r-.._,_.. -.L ..... ,......... '_'i ..-:=-',".......
. ,:. ..... : ........ . . ." • .t. li....... _ ............ t- :--,_ ........ •.......,........ , ._--'?..... --_-J"i i . . : . . . . .. .... . i . .' i
"-_-'- i" =" !. • . ---!'..... : :..... "' "'="-'.='"-'"'"i" z i-:, "'.'=.'"'!-"!.--...... t.-....l-. ;.... : !.::E-.-[........ [email protected] p..! .I.:: "- "I. '",'"i "-i''-i'" '" ...... l..i ;..l..-_ll ..i.:'.:.:....... .,_.
" _, . .i.." .,....i . . i ..... = ." . . • : ...L'="..L" ...... ..i....." .. .... " d:i. i ._
5 ......... Ii l
.... , i''.i _ ...... _._ .......• v.':. ','...i _ , '." _ I -'"
." .... :l=..--r--i..I _" .................. • , .; ...................: .1 . _.k_":; ._.":" .. ;.-[. .."1....... ......= ..... t-........... r. ........-.._.,F_:" ..F:.2=.'p.q ; .. i.- _-'t: -i- i'... : ""'..a .. -n.--.i-:.'--_l_. = ". • ! ",- ._". :'.'-"='i.:."-"i. • _ .-!.-.= ..... -'r---: .... ... i . :"i:':='" I .. • ":: •' ' .' ":'' ":'l "1 -" " ": I . i i . ._'--'l--_.".""=i'l'4:'' I""','-:t -=-'i-- = "._il_=.="'"_,', '-',i.-.:-."i_. _ ......... .,-........ i......... . ......! .i • i . • ". • i .... i::" •. • . i -" .I,--_-_=" " ',+ .-I..... l ..:,,#-.-1.. ;-....:....i.... ....... i'_#..-I ........ .,.-........................ : .... .= . .i .. " • • .- .i • • i i " : • :: .': • • ! : : '1" i .
el 0 .[", . , .. ..... . _..,.._,+'i.. _ = ;,7_. ._'" I.___ i ",............. "='l" I :-""::-IL ."E'-=."..-i'-.--'i---'-": .--"_i'. -'. b ....... .--I. • • I..-i.-.-'.li.p._:.:'"" -1-_| ':" .-r'-/.---;. i...---Li---I:--ii==.'u-.-- -.. =1 "l|':'." "|1-" '" • .-_a "a - ,.t.- . . ... f..i :(I;-'O) i. I ............_-i,.=,...='-I..'......._=i.... i .i..... :-._-.'i,_,i_-_,=.l--I,......... .1-...!.._-. = ...i'.:M ' I :. ! "'.=i" "" : I. • • S .... I I ' •. "'. " . .......,_4.......-*=-i",='','".d.--,.--'-,._"._............_.-4.......;.....,"_l.........-._...............- • I.._:---'--_-" -- :':":" :: %= '.'.; " ' "" i • ".: : " : i .: " : : • I 1"
• " -...=i"#H:'l '-i ='l:.-:!.'-'t+"_.i--'===1,-'"l:"!'':'" • ":" ." "':'"-; ....... r'":"" i,l_0-= " :="..'..I.i,.i--.L. ':: ."..1.. ".,"" • =i!=..i • .= . :"':'i'" .I._.L.-::':'" " i .................... "_ ...=.. = .... =. : ,
II
.lo:,..-[.---=--..---i-...i..,:l...-r-:i,,;...... ....-........._-........... ,.......... : .. , .....,._..i..:..'..,:F,_--..rl,. .d+.;-::-l,. : t=-..'...............-. :.. . :...;-. '_............... ,....... .
Z-.=:--.." ": " " - l_:-----.-I:i4- • i-. 4...... i...: • i i ............... : • =.....• . i. • ": 1" • . ....1. '1 • ".- ..1:... : .1" ;" . . . • : .I= =_- ' " t '" " ' I..... 1""'i .:..-i=.'=.[:;.:,,_ -." .;:_ ",.- !..... ; ",""; •:....... ,.- ."....... . ; ........... I . ".
• -'.=":'F'.':;_.=,'_b_.'-_.-_".-_.........._..:................:.-..;.............. t
(I)|"i*'EC)l.i/:) 0 ."_."'_.1 .= .."""" ' ""i'"'/= "': "=" " 'i ....._1 .... ....___.,_:,-J _: ,, ,.... : • .- • • : • . • .. : • . i .j- |,.'-,---...-_.'.-..-i.'.-,-'_'.'r--,--, ....... .'-..................... •.......•I : • . i . •.... : ..... i...... i-. i ....... = • • i.._!..=....i--I..! _...._...I..._.._-_I,..-_._.•:.-."....--_ ........: .......... i
.. • i . =..I '. : • • • • ' ". ! ] :" "" : = : • • '..=....i.---._: ....... = • . .i....i...., ...... i.--_._ ...... .J-.-..: ..... ..: ..._...I ...... = ....... i • -'i
' I• :
200 ...................... ,----_,-,--r ..... r •" : • •, • .,. ::.:-.._i...=_ i:';..........": • : I• i ................. ...-
-..! ...... ." :.': "" i ! • " i .i .................... = ....... _"="'-_ .... _........ ! ; ":"'i ..... ,II: ...... _I = II _I_ ILI--4 II III : ........ : ....... i "'i": " " ' " I I I I
.. ; ; ::i .......-:::'-:--i:-i__ :-; , ...... i0 "r:_... :..._:'k:-i:_'i ......"":""" ":_=................... ;....... i--""--'i
' .....'...... ::" "............!":..... -.............' "! ......... :....... I(DEG) "-"_." _" V i ' ......... .L.: " i ............. :.. i .................- i ................
.... i I ..... "........ :'%::'- "'i" " " ": "-!"-". . ......_.:...." .. i ...... " i . '.I- " • ! ..:_................... :'" I; .'i :..-.:: ........... _ J .. : .'l "" : .... -r.I .-P...:!
--4 t"-I'<°'° i5 -...-.-;...... "'" .L..:::'..."'" :....... : .... " ........ ; "!....... .'--_"1 . • '11"""""'" ......... "1:":'=_ --4 :.... : • : ..'n'-"-I =;.=;_--'_'_'-.-- -'. ........ .'" ": ..... I i---'l" • . -" I • "|"" _" "'._..... I
........ I = ' ." ' i ....... "" ,. : ._.-..." .'4"" i':'-i.:"l" "h--'" .... i =. • -li" : .u:i ....... 1.' . ! " i ". ..... : "':: ..... i ..... . "'r ...........
• :'-;.b..:_'".!-=,'.--:'-l:':: ... :"..=L i:=,4,.,.'.-_...,..-i.... --I. .i ....._ ..• .: : ................ : .: : • .. . • , :.= / _...l. =.., . "1.. .... =.... _=._ .==:. _-...|. I ................. i..--'
•. :...i. I" .t:-..! _:'i " • : " !: ! .." ;. • • ' " : " . " " : " ; " " i ": :
"l 0 ,,._,-,-_.._=F_.'=-I:.-I. :! ;..::.-:-.r-I ...... _... • _.................. _:----;.-_." "-" ...... "-"=:" '"":" " ':. -.-" "-4-. _ ........... J ........ i ..• ,I--i'-__t_" _,':''' i I ..... i'-IP..... . .,..
(VOLTS) .......... ==i_:'l:.....L.:: _ r:.,..l._-,x_=.'-_..--I--...l..-."..... .=-.I ;1"".i -.;-. "1........... I .....' : ' i "=" " " : :: " " : • ".... • ' !....' • • i ! h i / " -=L • i ......... _. ."_-..',"'.'._................._--.....................-,.......-I...... ,..i • i• .. ::i= .= i . : : . . i ...........-............b._.lg.L" ...... .,....+-..-,........-4-,.,...-I.........., , -.:4.....i......
• • ....... =.- • . '........ i " ".! " " "'=5 ._i....i ..... ._:: I...... "-'..-:.: "-':="'::-: i • . .i . " • | =1 =J .- i.. ] | -I.-..• : ':
2 ._ ....... t.." _ . =......... :';'= :_""=,• ...i :. " • . i: ............. I....I.: . ..: • i:..... . : r - I-'..:- ::......... i---.• ! .............. .,-.... r_, 4 .... , -i ...... ,-_--t_ ................
" i. '' ' I .... I .... • " i •_._=4.-_-................ i[:_,i-i,i.I .......r......... _'_i".....1.............i .... :...: _ ":_-.'"='::: . i • i . i.... •.---..- -J........... :1t..'i,'.-i._--_"I:.-=._.-;--=--_.,..-...... ' ...... _ ..-II_r_t=_
= i" ." . ..l " " :" : : II _i,.=l-_ll:.|...%1 ... " ...... • •'...... • .""i=.... :" I .; ": "','.ii"' " ""_--= I:" '='..... "' ..--III. "i......... I" I "'1 ....... _ ....... =4-....
_ . i ............ _ ..... i =..;_.;,_i _ I ...... n-:-P'_--I _'t ...................I" '-_",¢ .......-...-,............. ',,'-I ..... ,...........I-:=.. '..;::.;T "" " " ".:.':'_"_z'.";"T'I _.:.• ", =""! • ' .r • : . " "=" • .
(VOLTS) ...................... ...........• •_'.-t--t ............ !_'.._." ," 4-.'41.,-:1--:-_..... .. -:.--:.-;.,-!......, ...... _..•., .. -.'...--_-=..---_i_i=_-" "_-..',--.i • ---_-.-.:-i:-,l---I ........... i-, 4---_i-- r .... 4--I ........i : • : ./ . ..:...'. = •- :" ." . : i . . i . • ........... i .... _.-.+_-_i-_-'--_---_...,__-,--i--'l ........,......._.,--
-2. II ..-i..:.i..,.l:. i'"'l ... ;..../. : '"l "._ • " .i----.i_-! -.lll.i,,,=i= _Z... ." ...... 1--..
. i / ;
|0U .... i.- T"T" ","-r'. - '-'l .','3_..."qF.._ .._.. '_' ._. _!" ,':=I! ..,i-:'=.,=...-.=l-_..._...-r-'_:,:-- --" • """T"' "I "1 "
._.i..._.i.._4;,......._,_._i:.kCd,_._i.._.;__.,..-..:...i_.=..i._.i.:'._.L • .... .I-4 _..",,.:.=--_:,i.-.-i_._'""_,'l'"_==+_,_i;'_--_ .-_ _::,i;;,=4,....'_+.4..4......I..-;..• . - r .i ...... =": ":. ' .= .: • . ". :'i " =' .i ' , ' ,:- - .= .:= "-." i ! I • . • .'."
-,.i.=..1-:._-_- i,___l."_" " •, ,, ,,r=', , i_¥._.::;. ..........A I n .': :1. | I i.".il...:...li:..i.'--I:.:--. I . r.__..._=[. .... '4 . .:r.i.;...i.-...ll ..JLI.._I..:..h.i....:..|l.:;
v I.m=..&_ ......... = ...... ......... -" "=i'|-'i|l_.'_i---'l--I_ "_ :='l=l':t"tt _ i_l'_R'h_.'.@Ifl'- ,' "'. • _;_"
(LI.._E_ , _li"_l:.-._"• '...;'=i "==.=-i..=:.-.".m..'.:_._.__..=._..1_....._..,,i.::,I,! ii .I .=..r...i, il .:.I .=i._.1._., ..__.h_,.l_t.._.,,_i...,i i ,:i ":..:.. "',! ..... '
' ____i.!-::"........"......i-.".............. "" ."........... _-llt, ' ',r"".:i .r. ": --..=:.._: . : ..... . :.._ :::. .:i. _..-, .... ,.i = : '...'.: . ..
I/N
Figure 48. I;J Maneuver at (_c= 1.4 deg/sec2 (Analog Rtm 21M)
lO1
1966018034-121
300 ........ :--- T-7-; ........
MODE SIGNAL (" 'OLT$+ _ "_ --_ -+_-__-_ + ........ _ .......
"T(SEENOT_) _-_ +-+- : ,_%_- i -_--;---_......... u .................0 _--_'-_-' I . _ I ! ' ' i+: - _+_
-_-_-_-'-_-l--_-_-__ -- -_.'_'_.'- .-Y-_'"-7_-,.......
_-_ - !-,--,--__ _--_-_,._ -_
..... n • •
F ........
(uJs) ......• n • .................
: . ; .I • •
'i7 ....+t ' !lli i ,i;+ii!, I,,1il ' +
120.... .... • . : ., : , ........ . ; .....
t_ ! ................... :'" •D_C
IIi I I I i [ I I I I I I i _ I ] t I t I.i t..l__ __ .... ; . ! . .......
• :" .i _ : ........"..i...... : , .....
•_. -:: _::,: ;: :
20:! " " " ',. ................t _ .......... t
: I I200 . I _,., _ : _ ..... :
• :. - .....r-t-r..: ...... : .'._;._.'_':..i+.i i."LL L i."7" _ ...............----. '""_::'i ;:'! _ '.-_-_._ • •0
: , ..I : i ,...: ;
(DEG) : ,.. ".'-...-I ........ _ • •�._._.._-._ . : : . . . " . . . : : i .
= ....i:,: : '.... "'$ :'"l ....i'_- "P--'....... :"u "_': : . " " .i_ : '" . : '
: i.: ..... i' ":":"'." • .......: ............ : ' : " i "
H'--u.-'i-.'":_'i ..... : ;1_• : .... , • .. - .1.;. • ..: _..'.. . • ..:... :. ._',u.", 1"';'"_""I . ,' I : ' l "
0 i • •-i "i : ' ' ..! :.--'_-"" ....... : ....... i ...... ' • -' '
,-:7_:.-r-r-,-t.,-_;.._..; ....• . _ : : ,: , ,. I . : : •_. . d "" " ',i '.r..:.._.-i. _ -.".
" ..... t_"':i7.:':'::'":-f '" ' , : , ' i ._.... "--i.i ..... :
(VOLTS) _',.,."" , n ! , ...u • u.... : . • " u ""
-5 ".:".... ] ..... ! "" 1 ; ' : " i ---'f-'':"--J "" : :2.5 ' ; It" ............... , • ..
:'" " : • " "'r''"i'.': u • . ,: " • "_ • .: • • • ..... : 'i i • : i ...... _.....
-! .; ...... '- ..:.,d "" " ..... '':'" ' " i i i" :..!- .. i
:._- k---:.... _lltdlAJ +' :....It..,:...... :_, " .l_i:.:.i...,.:..+.j::.+.+ :'0_. . _Ip_ _.... !..... :. ",_._ -. _ •....:"_.'"
I ....... I " ' I ..... _'ili" _ "i:ml_ i " _ ' : i ."• -.+..+............ ..:_.:.(VOLTS") . u . • +'+ ":"-'"'_ .... : " I ._ __:'i . . '..... . : _.: ;..;..:.i _ : , ,"-._--.l_l i ........._.... ;
"' + -,.s , I:i . •;® +..'k.......,+........u r ................... i....................
-..-_.-....... -I........."-'i.......... :_" "".... ;.... i"".... , ...... ".. I-., • , u . _'.u ::-:..-_-...I..,p-:.,..._--';-_-o ....• • _ " " - • :." I : :. _ . ' .
"" .... _' ' i' ",'"."4""! : ..... : ,'":'"', '_'_.." .... .....':. • • ,,.......:,--i.. :..,l., ; , i ,.. .... : I "" " i--. :, • ...
o-+_':.:_..__ i _-.!-.-. ,._.,-4-._,.-i-.i-'_;ii,_"_-_:,_'"..-_:-t-.'n: .r._F'_:-._..-,:. _--.;.--
. AiI_ _'::p-:i"_t-:'.'_=.:'"::',F.':..N,liI:_:' i ":I .+:-a;'_-',_,_.L,t:...I.:+;F...H,:_::_.._.:,=.-..J-.:, "'_"":._:,1-................_.:'.-,...!,-.;:...p.].:"-_:_: _-_. :::t.] ;-:F:: .--..::.:-_.$-.'.4-'r_:",j!l; ":1":'i--'i_:_--t".'_:F_:I".::: • i' i.
- - -tw _r_;_:';ur,::..i ;:.L',Li:-'_':"_,iI:I,-'m-'I'_." ,,__-,_t._.::'.:_. '..,_L
•_':':""'--_"::":':]:."::__"_"+::'--_:L"!'::_'':'t'_:"::]:]":i::::_:::":::::::::::::::::::::::i:::_::::::::::::::::::::::':::::::::::--::::":_:
• Figure 49, 75° Maneaver at _c = 3"6 deg/sec2 (AnalogRun 24M) •
102
+ - i,'_ +j
] 9660] B034-]22
_l o!(,,,,sic) .... : ...... ;
I....... : ..... :-. i-. - ...... I-' •........ i . • " l . .., _.... -__..,._''_ ._- ..... ; ....... i= t ' J II , I . I • : • .' -l®."_............ I..... I ...... /
,%:','.'.'._:'.'.!".:'.'.".::'.'.'.'.::D.:'.::',',':',;, _l. . '
. Figure _0. 20° Maneuver at _c = 1.4 deg/sec2 (Analog Run 10M)
1966018034-123
,3oo-i:i..... :..... -;:, : : .....• ,,,; I. " ..I • • .'"L
;:-__ _ i ,: ....... ___:.._"_......_': i :'-.._--;-;T;_....."-':'q:'-. " _ T
MODE SIGNAL _{_LTS) O ; .w. i., • .! _ i i " • .., , I
_7(SEE NOTES) -*/ i i . ! .; .i-_ .... _ ....... _ I ....!', I i ! • , ...... ' : ""'"i"l" _ : t'J'_:'l'.'_'_.• " : ' ' " : •"' l.... a ..... I .=.h.:.l. i _ I --_ . I • I
.! illL t4 i ll!l,l!lili!"5 ."." ""_ ...... . ": ..'..----_. ;._...._.'..'_";"_" I...... : ......f ,;. I. I . I.'.=1,i I.J.-ll i...1. • I - i i . . I | | i. . • .- .'..._"+-i'-:J'".l:-_:i-:::.i;":._iF"4' i" : .-..! '",., .... ; ;: i. ..:-. .!:i.'l;:l_.l. "i ";_..i :! • ! ..-...i,_L_,..,,F,_'I.,,.,F,,_...._,_.!..... ,._........i...........,.4..
F 0 ,,"r'.-i'_, I" !'#"l'r._--;-.- ; '-.. : " . :•"1-!"_'!: f..4_..I-.._-,_-._.__.....":"...;.....i..,%,_
(L_) :'-H'" I.;F4:,,._,_,/.-I...,,,.._: ,, :_..,.%q.......:..._:,.-.... "I"'I : • J-- I ..-=I.._|..'I'.. 1 " 'l" "l"-I--"I" • i . . . , .p-.-.L..i.;.,,i:,....i..:.1--:"_-. , , _J-'_.L;".i..-.:......+._i
+5 =_L-- _.__' ._"_",'.,, ..... J. !_=i._,.a ._,__..,_."'I. '', j i
• ,............... I '-_-"r ............ " ........ ....._ .. I.._ ....• ._......_......;-I..,..l ..... ; .. i",,, l.,:L,'..:@_i....:_'L;-i.: L'.&:..':::.l.,.._,i..J,.. i,...', _...-..-i..." ;' :_:.,:'_;-'_'-'_:;._-:J::__-'._..,..-._..__-- ....'_.._:],_._..;,,,*'...:,_-.i...__ ....;'-"'::'"'1::'_'"_"_o - ',-:---:--_-_.... :.... ' -,-" = ." " i; ;., :,:_.'::-,:_..",':i
#_: _ i-"-'"| 'I ....... . "'I "" "r'-',-'-'t r ' ...... .._l..q..=_..=Nl,_.1u,e_l..Ii. i r . • "." j= I . i . . • ,:
(DEG) :=I"..'_.....rr#-'r'.,'-,-','-""r.r.."-..l"_'_..'.t_."'._;:'..,_' .." :" " ,r."!...".'m. "i." 1",.i-,@ I...I" "'!""'.'='_"_.;iH'.-'""_.'i_-_, I
"" l " ' ' _ "": i"'i""""i'"';"l "_,,,,_1_.... i._....-r -'ll-._._' i[.| ..-_'_-- i ; ".... ,, .. ": .. : • : ......i :. i .-:..: .... :.:. :: :;:u. - :
I =; . ' : |-m..... _. _..Ti r ......................... ;,,_........... -..."_.glTr_:. :';." .... :. " -. ". ._., ,'_.h;i_r:'=lh
_--,,:,._._',-_-:e,,_,*..,....+.-_, _,-,-:rr,_""'"'"FiF:'_:_.'""_'_-_'_:_i'"_:_
I ' " • I .'_1":I"PI"':I. "u. ":_q_r_ "i_1=_qlq_r:l"'_l !.ZBll_4hl"fl.'_lMI• : " : " :1 ::"!._..:--.l_J..._'.:...: r.,....:.:_.a,cmm.q;:., .:.
o " :. i. : !. _. r i_!i ;4; :;";I_.'t"';_I_"'1.,...,1 ..... i .1...J_.., ......:,.,<l_.U.._i...i..:.i.L.'i ....... hl_'_.i.....-I , • ,., I : ; • .! .., ; ,,...-,..i,...-.mE_,_ _.__._,_ .__.._._.._,,..,,.,,.,r._,,,,:_,._.:_.,,p]...,. +. i.,].,4-.4-,.._.,+,u;.,F...._:-_,_.,,._.-_._.'4;4,___ . "1. i J ;. _4.'1 .::h..._..J.I .iL.I s..l...::'.:..I • _...:...... .I....L..ll_=l...I
+20 ; i ' " ' I " '
, .I i ':;. ' '2oo.:!:-;"'_:r-r' -"l"-'.-,_'....._.,;.......""l......... : • ,• , r_ , • , , .'_.-,....--.'.T,'.,_...,. i I • . _ . al
• .a.:..... ! --._ "--_t.-_, --_':-: ' .-_ _:-I:-_-'=.: .... +_ -t--_."--I" " i i : ,, "= ":'": ': , ,,',= ,i • i :,., !- ,-.._....!.' 4 ......,-_*._-'...-.,-.-_..._,_,._-.--,-.--,-_.:._)! : , : i I ,-j:-:_j_l-.*l.--_.'.-_i--i-.-.l..-4..-l.--. -.-.': L.,
o _ ...._'+,-._.._.v..,'._i,t
• . . . . , . i ...... i I • ' •
: i. '. '. -' - i •i....;.-_..l-.,I..-i-.+-._::'_,<'_,:.'+....:"I• . " _ ". . . : . i...., ,.:-.."i:: "_._.: :i.. I. ";F ' :""_:i : : :
-200;' !....." ; .:..: .......;..-;,,l, . ._,:,:J_._.q_;...'...-_"! I ' _ _ "_:("_ ' !
5 :l :"i J :'' !': ..... r-r-i"T'-r T-.-,-..-.,_--.-..,.-r_:--i --r-i .......... I • :...... r" "1- _..... ,, J:.Jl" ' "" ," " iI "[ : ' i : "" 1"• : ""1 , ;" " : ".' " "r't",; ,-- , • _ : -: i , P'" i:!_-'-' * : I.-i-.4_-_-_._-'.-_'._.._u"i_.u'..: i-_' .:i,; •i I : ' • ' I . :'1 ! "l''l ' • / I" I I| _ ... •...I ..._: """II"'""_. .""'l 31.::.;..i_.--I_._.._.-.l.......---F_.i--_.;--. •1 I i I • " -- ..- .-i ..._ .- .---I_.._-_| ....... i, ', • I-" .t- |
"s 0 • -- • , " i "'', ' : •: • _ | : _ . : :,_ ,._..J_ .-.._--!-: ,!...._...!.-.,......!.L_'!-.'I_'......!:_.,.:.i•
_"') : :-::l;_!ii'!]::',r_"!i=5 . . . _..i--..i.ui ! : , I L. : ...,
2.5
i ,: : 1 iL : i......',:,'vOLTS)
iI!llHIiil I !_L_L_L_L_L_L!J;• . . : _ . , .
•__.;__ ........_i o ' "' _ :._ : " i i .. :.. •(_-s_') ......
........... -I. --__ _ ....... !.......... .I., .... -.' • :,.4---1..:-" .... I .......... ,--"
! •., .-' . I ; :,_ ; i . , i .,. ,- .....-I00 ; ; :. I .... l,.. 1 : . . . i : ....
_'T_ __ .:",':-L-"-]'"-;]'*::;"-:::_::_':J::::.'--__L'!:"!;_'.::_,'.!!','.'.=:_!:',',:. :I"
. Figure 51. 20° Maneuvez at Gc = _.6 deg/sec2 (AnalogRun 7M)
104
1966018034-124
r-I _ _ r'q r-I ,"1(I.) l I I I ! I
L:_ (,j (M ,--I ,--IOJ C'J Ckl CM
_'_:. c_ oJ _ _. c_ 0_ c_ _ c_
Og laO C 0 0 0 0 0 0 0 0
'_ CM CXJ OJ Od CkJ Cq 03 C',J • L'M
c$g4
-'--- o) 0
"C: • - " +:, _qgl l:::q _ 0
o m _tr"x u'N Lr"X tCX tr"x _ tr', t.r% tin co m
E-_ t G.I OJ C_ OJ C_ C_ OJ O_ OJ 0 0 -_ ,._o o CLI OJ OJ 03 OJ OJ OJ Od OJ r-I _ _ J_
,_ co
Q,) (1,) (1) 0
r--t 0) cu
o o
Ckl Od k.C') kO CLI _ Od Oa ',.O Cx.I (D Izl oq-._ _ ,-I ,-i 0 0 ,-I ,---I ,-I ,-I 0 ,-I 4_._-_ _
_D _ _0 ........ O q-_ 0
•0 _r--I _ 0 °_
_ _ _ ........"" ,Q 03 bO r-I _ r-I t_ r-I _ r"l t¢_ ,_"x W_
c_ o_
M
_, o o o o o + , o o oI--I _ rrj
bO _ _ tr_ 0 0 tf'x. i£\
0.,-I
H H H H I--I H H _--t H Hor-I
0r_)
E_
• _°a_.n co o., o _ _ _ ,._ t.--- co o',-:.t- .-@ tin t{'x tr% tr_ tr% tr'x _ tr%
,el
1966018034-125
Table ii
ANALOG S]]4ULATION _L_NEUV_R PABAMETERS
FOR 75 DEGREES YAW MANEUVER
High Thrust Maneuver Maximum Maximum AnalogAcceleration Time Lag Angle Vehicle Rate Run
(deg/sec2 ) qonfigurat ion (sec) _(deg) ,.(deg/sec) Number
i .4 i 19 -3 97 9 oa 21M
i _9 i lh .5 29 8.8 2P_
3.0 I 14o 8 25 8.0 25M
3.6 I 14oy 25 8_2 2
i.4 IV 19 o5 37 !0_0 15M
3.6 IV 19.0 25 8°4 IIM
[
FOR 20 DEGREES YAW MA_D-TER
1.4 I 10°8 17 5.2 iQvi
3.6 I 7.4 13 5.6 7M
lO6
i
1966018034-126
sec 2from their highest valaes at _ = 1.4 deg/ to relatively constant values ,J_C
increases toward 5.6 deg/sec 2• If _ , alone, were the difference, the I,ian-C C
curer characteristics obtained from both simulations shculd then be the same at
the high acceleration level. However, a comparison of the res_Its shows slgnifi-
cant differences at Q' = _.6 deg/sec 2. This indicates t_%at differences £n o:C
alone cannob account for the differences in maneuver results o
_'he steady s.sate Lag angle in a ramp c;om_nand, position-.plus-r&te,
system is proportional to both the effective rate ga.in, _E' and the gyro torqu-
zn_"_ rate, _C" The g_zo sine pick-off and position_ signal limiter are nonlineur--
*ties in the FA.CS which cause _Z to be a function of the lag angle_ _E" 'lhe
steady state condition is not .e_.Llzed for 75° (and s_m,l!er) maneuvers_ This is
true of both simulations Both simulations also show that for 7_ ° _m• mane uve r s ax
is attained neaz_ly simu_t&neously with '_E and a tnrust._off sta[e° T_,us.,cper--max
ation at this point is on the switching line.
If _'Cwere ie_;s in the analog s£m_lation than in the air bearing
; . si_mla.tion, the generally lower _E cb!:ained Jn _she analog s_r,'&hat.irpc.:,.,']dmaK
be attributed to a _C difference. However_ if _....were less in the ana.Lo@ sz:_-o
.o ula.tion, % should be greater and _max slhoul.Jbe less., in general, for the an&..,
]og simulation. '_ne results show the converse _c be true° Therefore, the dJf.-.
ferences in results cannot be attributed, in a consist.end; manner_ to differesces
in _tC alone•
The possibiiity that the switching logic and corresponding _ in
the analog siz_lation differed from that in the 3-axis simulation was examined.
First, the c_npliance of the arm,log switching logic wi_n the hardware test re-
sults was checked. Figure 52 shows the results. The switching line with limit-
ing was derived from the position-liv_iter calibration test results for a rate
gain setLing, _/_ = 1.55 seconds° (The switching line withoat l_niting is
shown for reference only. It is the logic used in Reference 1 adjusted for
rate gain.) Then yaw ;-ate, _, and lag angle, '_E' were -_ad from the an&log
traces at t_hrust-off conditions. These values were superimposed on the switch-
ing line graph. It is evident that Lhe hardware tes_ results were properly
• simulated on the analog computer. A compa_ison of analog simulation and 5-axis
107
1966018034-127
io8
1966018034-128
simulation s:_itch points was made based cn tF1e '$'E '-_,ndtmax v.¢lues shown in]Item
Tables 6 and Ii_ As previously st_+ed_ these ' " "_ _,_._ue_ occur s_muitaneo_si)' un-]
with thrust-off for a 75° maneuver° The compazison is shown in _igure 9]. l_-
is seen that the indicated switch points from the air bearing simu]_ticn Lie
be]o_, the _'eference switch line, whereas ±.hose from _e analog simu]u%Jon e[-e
distributed along the reference swit__] lineo The dispersion of +,.,hes.wit.Lh
poim,s suggests that a statistical trea.tr,ent cf the data is approprla.teo A
statistical approach is further ju_-+_ified Jn cons ider_._ion of the un_ertain*ies
in t._e accuracies of both the analog and ].-e_is aimu]_._.cr data and un ertsin-
ties concerning extern_.l disturbances whic_ existed d,_ing *.he .',,_e'-_rlng _e._t,:
(air disturbances and Cogo offset torques, for examp!e_o A q':_t_St-sta.tl_Tim.L
comparison of t.he results from the two simulations is presented in T_b_- LPo
Deviations are given as a percentage of the refere.qce as indlc&ted° T_he el.
fec:t.ive r%te ga,_n comparison is bg.se_ on the dat<J._ho_rl [n Yigure 9-§. [{ere,
effective rate gain is defined as
ma_'
KRE -
It is seen l;b.at the KRE for the analog simulation near.iN -:cincldes with *ha.*
derived from hardware _est data; the percentage deviation has s.n a.ve_age value
of -0o08% a_]d an ms value of 2o7%o The _-aKis si]r,'ulatcrdarn. yields u. Kp_=
which has an 18.4_ hi@her va,lue and this comp._.,es f_.ir.]_'well with _he 2°._l_
higher average value fox _E obtained° The l(.ngez "M . [o_{) and lower _I
(-7°5%) obtained from 3-axis simul.atcr data e_re ,-onsis+ent with _he indi:ated
higher KRE. These results strongly suggest that, doring %he 3-a.xis simulator
tests, the position signal lim.iter had an c,u.tput in the 19nii,ed ru.nge a.ppzo_i-
mately 20% below that Jr.dicated by the position-limited, calibration tests° S_b-
stantiaLing but not conclusive evidence of this ecu!d be obtained by a rerun of
several conditions on the anal.og computer with <.he position signal iDr_iter-set,
in the limited range, to limit 20_ lower than previously°
The foregoing comparison c.f analog with i.hree-._s smmia.tcr r'e-
sults refers to the 75° maneuver condition° TLe results from two 20 ° analog
simulation maneuvers are shown in Table Ii for ¢.ompariso_. with results in
lO9
1966018034-129
11n
1966018034-130
Table 1.2
COMPARIS0}_ OF A_NALOG AND 3,-AXIS SIMULATORMA_IJ%_R RESULTS FOR r5 DEGPEE _v!ANEUVER
Percent Deviation from "Hardware Test," SwitchLine Effective Rate G_in
Average _MSDevi_,tion Dev iat_on
Anal og -O o08 2 ,,7
3-Axis S_mulator -_-lSoh _19o[
Percent Deviations of 5-_mis Sim'o.lationResultsfrom Analog Simulation Results
Maneuver TL¢_e M%xim,_, Lag Angle _<.,ximumVehi<:i_ B_.t.e
Average RMS Average I_-S Average P_IS
+7_7 8.6 +22oi 2h o2 -7_5 8°3
Tab].e 13
MA./glMUMIAG ANGLE C_{PARISON
FOR 20 DEGREE MANEUVER
High Thrust Maximum Lag Angle (deg)Acceleration_
C
(deg/sec ) Anal3_ica,l Ana,log 3-A>'_s Simula\ _r
1.4 16o5 17 15
3.6 iZo2 ._2 _Oo5
IIi
1966018034-131
Table 6o Again it is seen theftthe 20° maneuver has nob approached steady state
ramp conditions at completion of the command° Also, for lag angles of the order
indicated, !-(° maxLnum, the position signal is not so significantly affected by
the ._onlinearities_ Figure 50 shows ti_atfor _ = 1.4 deg/sec2, a conLinaouse
thrust pulse exists from initiation of command _hrough the time at which ma_i-
mum lag angle occurs° That is_ the switc_hing line is not encoantered prior tc
.' Figure 51, where c_ = 3°6 deg/sec 2_E c , shc_s a single pulse dronout w±+.h
_YIax
recurrence in the sa_ne direction to the completion of the 20_ co_mand and the
point of _E occurrence° It appears than for- a 20° command, @E is ttlenmax max
primarily dependenb on the magnitude of command, ?C ,, the command rate, _C'ma_
and the acceleration level, (_c' as fol.]ows:
12--; /max max
Table 13 compares the '_ obtained zn the sJ_n_l_tions with that obtazned frommax
the above equat_on solved for rominal values° The major difference is that trie/ P
5-axis simulator shows a somewhat lower ._E at (_e = 1 o_ deg/seC-o This dif-m.ax
ference is most likel?.,the result of aifferences in parameters which appear in
the right hand mez_ber of the above equation or is attributable to external dis-
turbing torques in the three-axis simulation° The _m,_,g.obtained for 20 ° maneu-
vers are roughly the same in both simulations.
4 °5.7o2 ACQUISITION EVALUATION
Acquisition time, TAC, is the most important char_acteristic as-.
sociated with acquisition in 0hat a TAC increase cr decrease is in direct trade-
off with an on-target viewing time decrease oz_ increase; respeetivelyo Acquisi-
tion results from the analog simulation are sho_a_ in Tables 14 and 15o These
may be compared with the three-.axis simulator results of Ta/oles 8 and 7,
respect ivelyo
1966018034-132
Tab _ 14
EZ_ECT OF ACCE'_ERATION ON ACQUISITION,qONFIGURATION i
Mix-'.ng Ps.+.io = 2S&CS - Enable Detector at 0°4 Degree
Variation - High Thrust Acceleration(Low Thrust Jet Switching at +22°9 Arc Seconds ]
Control
AccelerationAcquisition Time N_rlber of Analog
(de,/see2 ) (Seconds) Chan_eove rs Run
Yaw YawHigh Low , __o _c
T_ru_t Thrust _EO- p =0c___' -__ _EO=____*__ __:0° ---3°
1o4 0o12 8°9 2°5 iio0 2 i 2 2]__&
,_2A1o9 0_12 11o6 5 °9 11o9 2 1 2 _
.0 0°]2 9°0 4°9 Y.9 2 l 2 23A
• 3.6 0o12 10.9 _ o4 7 o5 2 I 2 2_A
Variation - Low Thrust Accele£ation
(Low Thrust Jet Switching at __iCArc Seconds)
Control
Acceleration(deg/secm ) Acquis ition Time _]..__Joerof Analog
(Seconds ) Change overs .qua.
Yaw YawHigh Low o
Thrust Thrust CEO='+3 =0° =_T_° _EO=+3° =0°
3_6 o.z2 llo6 3o4 8.0 2 l 2 25A
3.6 O.06 9.8 9,8 9o8 2 i 2 26A
i13
1966018034-133
9_b le 15
._A_LO< Sr4UI_-¢T!OP,E_-9_E.CTOF
]4LX_G BATIO ON ACQU_ITIION
9
(_e = 3.6 deg/sec-, (_f = .06 _eg/sec-, eTl = 0.4 deg, __,_::_::0 deg)
Acquis i%icn
.z TLr_e .h,.m_be r of ._ iog
Ct-._:_i_nlr_tion _! (se _) ._b_&r_e ove ±"3 Ft_n
Yaw law
i 2 I0.0 ! ]-&
5 6.2 2 3A
h 4.4 1 2A
IV 2 i0.5 !- I!A
3 8.o _ ]3_
h 6-9 _ _="-
Acquisition characteristics are pred_Jirm.ntly affected by @E0' the
difference between the f_e sensor and gtTo references at completicn of maneuver.
"_9 is readily controlled in the analog sixnulation but is neither easily controlled
nor measured in the three-axis sLm,l!ation. This and other differences in terminal
maneuver conditio:_s, rates for example, disallow a direct quantitative comparison
of acquisition results frcxn the two simulations.
' In Table 14, the analog results show that foc Configuration I and
EM = 2.0, a coarse thrust jet re-activation, identified as the "number of change-
overs," occurs for the magnitude of _EO = 3"0° and does not occul' for @EO = O.
The three-axis simulator results in Table 8 show that, in general, coarse thrus%
jet re-activation did not occur. This indicates that @EO was nearer to zero than
3° for the three-axis simulator runs. It is also noted that the acquisition
times observed on the three-axis simulator were generally about the same as
shown on the analog for _EO = O.
114
1966018034-138
The arm.log simulation results in T_bie ]5 show a trend cf decreas-
ing T&C with increasing mixing ratio, 5a_' in the rauge cf % evaluated for both
Configurations ! and IV. This +-rend is apparent in The three-axis simu_lation
results of Tabl-: 7 for ConfigIL_ation IV only.
T_qoical acquisition and ILmit cycle oscil!cgraph records fyom the
analog simulation are shcwn in the following figures :
C
r- r- _i
Figure _deg/sec >") (degisee_") 'E___QO
52 __=,', o ,? o
55 i.4 O.le +3
36 I .h, 0-12 -3
57 3.6 o.]2 0
58 3.6 o.eS o
4.5.7.3 SACS L]IIiT CYCLE. EV_LUA:TION
The analog simulation SACS limit cycle characoeristics cf Table
16 may be compared with those from the 3-axis simulation in Table 9_ Limi*._
cycle position amplitudes are in re-_sur_bly good agreement except for the I0
arc second tPn'eshold, ef = 0.12 deg/sec 2 acceleration condition° Three-a:×is
s_nulator runs at Lhe i0 arc second t_hreshold showed an increase in amplitude
as _ was iDc-,-easedfrom 0.06 to 0.12 deg/-_ec2_ Analog runs show the oppositef
effect as do the 3-axis s_ulator runs for a 22.5 arc second threshold. The
limit cycle during 3-axis simulator tests exhibited a low thrust va]ue duty
cycle approaching 100% (see Figure 46) for the !0 arc second threshcld with
(zf = 0.12 deg/sec 2o The corresponding analog record (see Figure 59) exhibits
a much less severe duty cycle °
115
1966018034-139
..300.--- _L"':__. ' ...... __ .........
M<_e st_N_ (VOtTSi 0 --_ ...... • - : : t7........
IT _EE t',IOTE5_ t-- -_ .....
-,,ooL_:2_ _ ._+_u_,_ iI +-- I, +:+:"::::2:]
. .... _ :_-+-_.;--i--_.- .- P- _. j--:'_+-b.-.-
..... +. +'_
(Llm -.-if-+ + ....... : +: +-----+'---; t........++ + ---+ :$+-++' + . , : . +-t G :. .... +-+ : +_ +.
L ...... + ;+'__ ..... : . , __ 2 j , ........ , .'.t_ " ' i '
_----:..------..'.--7.- : ..... :-- -_:_: : 't+ t ?,4:+:+i+_F:,,_ 0000i:+:+: ++::--+_ +--_+----: ,---_+.,. ++-+ +;
(DIG) -'-" " ...... _ ": " ' ' :Li__ ' ! ,. : . :..; . . .. , , i:=t-:_:.+ ! ! ; !"-+ + ..... : .i-J :. ! '
.-1.67 _ .... :"... ; . . , ",, " : " " . ....... 1 ....... - .
-01 i , t ' ' i ............... ' ;,- ' ' : 't" ' ...... +_ +-- .............. , - l,.'.,_..,k..+..... t
• - : i . :'.- : ..... _- .......... :'-' ' ............ i.r.4"'[ 4. : • "I.... _ .: • , .... ll--'P1 - , t , • : • ,.-, .L..I.:.+.., • , .1,11_= n
_E_ _I _ U , _ " [ l , [ .... [m [ l " l [ " I ' 1 .... l" • .,,[| [ s, I | l I,' + " " : ' " i : [ I : !1: i [ " I " l ; " I" 01 ! [ I ..... [Z _': _; [ ' 11 l :+] _fjl: _ [ _ !" 11
'-I • - - ' ' -' _ - _- • _ - ,+-: .._+-.-:" 44 : _,,.... 1 ..... ,a,_i_ 2" : ;
........ ll l I ' l ......... : ___:'_':_ ' " "• " . : • , ! ,i'" ' ......... "'__,." -_...., !' • 'll.ii' .
.... J I I_ . . _ I I : ..... II i : _ I" ll_lli : :: : =_. , :1 1 :
I.. i ' • l .......... . i • '11 ,: i-- _ • J 1_ ..... [ 11_
.... ; : "! _ ' A _ "' l ' ,_' _ "_''
[:L::i : ,::': .i -. : • : :. :.:.:-: : '. ' "
' !v(_c s_comos} .. •
a,L.',..;....L.:J......I..L:._.,....,....:...u.:Lu::.; .:..:.;...:]..++..;....: : : : . . .I : lit J : _ l l" "' I ; l :
5 " O' " " l.... II .... _ .... _ "" "ml l "_ "l •.i '_ ...... _'" i[ ..... I'l I_ .......... _ _''l "''""" + "m_----" _............... I l
..'_s't .'1- ..s. I ,I..... +-, 1"t"-'-4. . "i"l'l _. l .." I • .-, I ......• : I "[ ii "1 ......" l I .. "]: 11 " ". ii I :
ir..--+.,.t.-, .-v................... '-..,...I-................... "+........"-t--'_- +--.--.......................'. :. i ..*.... _ ........... I .: .........c..........I"11_11 I .......... : II ""J-@_i,,.';+h:i"L " I "
[" .. l l I l . • • " I mill..., il ." i" . " l " " l I l[ i _ ":II''I "" . • . l '
_:" ".':""I-" _l..[..................,'-".-'1""":":......... :.... : ....:l:_lt._.-..'.'!.'....'-.................,...,...:.......(VOLTS) ..... ;.............. ;.-' l : ' : • ' ._. • ....... :., : • • •
0 ....: ................. l ...... ; . : : ...... m . I ...... l _ .................. I11 .m .........
; .,,,, I,., , -Hh-,.+o.oI2 s-.i..i...... ....' I ..... I. I • ....... +:......:......._._+:! 4. t:.I::i,:I ..i.1't 1 I I....... •.................... + ..... , ........ :2_.i ................
.................................. _ .... ;.................. :................... :'.. , ......... ; ;
": . " : . ..... : .: :.'' ::..i " .:..'.:-.. :.:.'..::..:'::.'::R-:':.:..-:::-'
(VOLTS) .................... [ ...... ' ....... : : 111 " : .... i
" ...... I " i ....................... 1 .........................
--,;. • .................. : ............ , ....... i
(L_.S _ ) ' ;....; ..... : .................. i .........
:-::l:'":z:l'.a..:I:"- : - :.... . ........ ! ...: ....... i ..... ' ; : I_ _" " : : "_+_+_--"P .............................. : ... i_--'--'i .... i ..... r ........
Note, 1. _C " 1.4 D_ll_am22. _F -0.12 t_P_K 2
Figure _4. Acquisition and Limit Cycle for _E0 = 0(Analog Run 21A-l)
ll6
1966018034-140
.... ,_+""'-'_-_................ -L'-,- ...........................
---_+-_LZ$_+ .L _. _+_+++_+5_++._-._--_--+:_+- -- - _++_/ + ..... L._ + _++_ _MOI)ESIGI',,L_(VOLTS) 0--'---'-'-'<",+_.... ............ -_,-'+-+-rt.................. : ++_ i . . . " ..............
+r_+t_NOTES) .................................... -.............++_ .......... - 1. + ................................
-. _+++ . :--; .+--+-,--i_!_-_- ....Z_.L-___--LL+Z__+.... +.............................
i ; ; ' ' ' ' I ' + I I ' : ] I , ' I I•-5: • _--- . ......-,-,i ..... •., ; , . , ." ..........
• _ ...... + - : - .... - ••-.+.':.-.-...::..,,• :.. .; ... i " _' " " " " '"
F 0 '_.._ _ --- __- - , :
(_) i :: ;" [ ;--__]:; . . ' i ' " " ",--'":" : ",;" : " . ' . •
1 ' . ' ; , I i uL I ! : ' • ' , I + --
...........+'_i--:+-::_-=_-_=s_ +_4:+I_J+=4:-. L- i ..+++'-'_"--- + •,. -,.......... + ..... . ,, + --__ .-5______.._.+_L-L:__]7++ • :t.. ".L:[_.;."_-._--,.,4...... " " "
,_E_" -' ' "; ....... ' : " ""' "_""" ....• • -{ • . i ...... :.. . ,
• " : "J ..... : ' '-L+7-" i ....... : _ , " " _ _' _..[,L.[ "
-o,_,_,++ l..l!J!+ !i-h_i++ if[ ++ ,+ +;+?+ :+ I +"+" J'.4:"_:-t:'.-+:+,::. -+ ."h":: ."!./ : .' ': :'.. _ .......... :-:-." "'-+:"'1']" I . "": "i-., ........ |'.i, . . . .
...... [ i ....... I ! ...... , ..... •
,+._ oi_J: ..... _ :' .... :: : .......... ." -- _-- _ _ --,...... '_............ I • I _ • I i, I ' " "..................... ' . 'k:. , +, . : : i I ' ';. :.; ..: ....... l ,---; . -.. _- ".-_-! . LJ --;
]-t:_J j I _ ;, "..' ' , " " : • I ; , : . , - , , ;.o,-r-_+;-4 , .+J=+ ,t ,H!-I,+__L+ j , ,+-r_+. --+,--m-_-, i , _ +--_- '_--I--,--II "7 -I- , z --T--t-,-+- . - LU
-: .: .... ; _ . - ;. . . I : +I ' ; _ , :.--L-L_; ..___.L_ _L_L_'_:____t_+L:-..:-.-k+"-.k-_U_+' : + .:._ + ' :• , . :. i I _
/_ ...... , "", "" ' _ |
o_ ......." ..... 1,d_
(._ICS_ONi)S) I t : ;, :. ..: .... i i4- ......... " .... _.--_, .....
4,+:,,;;i ....;......... _25"1"-i:_1'-J "_ _.:._..L. : "" "_ • "t ......
_-'_"_. ' _."--'._'-o'_. ....................
'_,i_:'F'-':_±:+-.......... ' :|. l' :1.!1 "'l ...... it.-: ._.,,.1. = i = '" •• " ,%!i = .:= ....... .." ......... " " _ ...... • ,
•, °_.L::i..!. : / _ ........ ............• .i "" ........... I
........ : . -..- ..... .-1.. :........_i ......._l....i ,
' I I, i . ---..4, _s_:i_£_"...... -i, -, .....2.$ _" *"_ ...........
! :::: !iii :........ _ +(VOLTS) _-_./::..i+_::::::; • ...............
...... i i i .......s _,_.--T'.'I:'-_::"!."":'.":...--............................... i
....+ .........._.......... .,.__. . . _±--.-.-. . - .... ".-_sl 0_,_- : ' • ...................
(u_4(_.'_ .......:...;..." ...... • ........... :......--- .--'r ................. I................................. ; ......... . .......... ! ...I -! .............. , ........
I"..... i ......... '............... -- ' i..- .............. '_ " _ "_. "'" l: ........I
....... ....... ' ' • • I= ,_ " 'i ; _ : ......... --I' '.... ! " ' I .... ' ......... t'" _= ' I'"s" I. i : I =. I =r •--I ..;..._'=0 I,IAI"............................................. i ........ ! ..i+_i .. ,.,,., __...;...i ,,, l _.. ;. J..J _I "i ;.. • .- I.. l.._i
' - - "...............;..........:':......................................................................................;...........................................:.........:_:_::::::::_:_:_:_:::_:::_::_'-:'_:_`_::_:'-'`_:J]:'`:_'_':-:_
No_, 1. _ . 1.4_/S,_ 22. ,_ -o._ _,_,J
Figure _5. Acquisition and Limit Cycle for _EO = +3 °(Analog Run 2].A-2)
lit
1966018034-141
: '. "'".." "; "'.'i.li;f.llii":,.il..._7_ -- _ _" _ ""'. : : ' .&. _ ..
_O_E SIGNAL (VOLTS'} 0 _ " '
i i (SeENOT_,,• , . . ... . .
mq
t]
,,_ - i : , : f :., , , . ./ I ' , . i , -- . ,
-,_-,-:_--I._,-.--,+-_-,. _-,_.,-,..... -_ .................... _-_................. . ............
;!--t.f_:;'._+_:+--_!------,: ,-:.-:-:-I-._ _-.,-........- _--_-,._ ti--:---F ° "t"i'-,_-.l"#'_"4.;'' --'J.,-.14"-_"_-'i_--'-_-'i-_'_',': i" _.... i--,---' ;-_ ':, ............. . ..... _ i'-'-_'_-'=-'--......
(1.iS) -I_.-,_,---t-,-i-.;--.i-_-.-i--.-!-,-_._i----#--;J'ix'-!---!----,i-4 --_-- ---_ .--i_.- .'-' _-.,-.4 _.i ";- +--' "+......... _-' .... " '--t---;'_F .":--:_-"-_ "4--,l_--l--,L-.-i-,_--..I-.....I_--I----i.-r-l---I------:'--i--i--+-i---i---_.---;--_ -:---i- .L "i- _-i- " !" ; -;" -i,..... -.i.. ................... ,____, ....-'-I-:"1" ;"l " +'-i_"" .-!_-I---i'-,'[--'iD.'. _-:': _"i';'-:"_-! "i i i-i-! ! •-i... :-: '----: ..... ---;----- i-..t.-.'-., i..,-,..,_._ ....,.L.i_.;._..:.. .J- ...... I.: L.-;,.-L.-i.--;.. ...... i-..,----_ , ----.:- _ -" -' ............... --' .... _------i---:.- !- ........ -_
_'I ,'ji;' .:il.;_i.i;:.. ,I , : , ' ' *" , I i ; [ ' ! ' l ', i ! _
-I. ; : ;..I -- . , • , .... ., , • • • , • , ; , • •
,J ". I,i '. " , , ; ' ; ..... : , '' " " • " ';'. • . . , ',,-. '. • ,. ,,. i .... • " " i ': :'; . • .,I
_EG, .l..i::; .._. :. i ''":'--.'. . ; . : .
i.... i...+.4 ..... '-" ........ ; .... : L. ...: :...... : : ..... : ..... : . "-1 6, ..... i ...... :'" ....... ' ......... ! " ' '
_.o, i : I ! 1_4_'f i_L.]_Z_i I n, it:i iT " ' _ :' ' IL] i' _ _ i I ' _jL L ', I• .... ,,, ,:r,;-:-"-:';-:...,," ....., ,:":'....,il[l.,-c-:--:;-. ,.......... ,................" ' -. :: : :' . : •' " 'i"! .; .i • . - i ." I ............... I " I' ' " J " I • ' .... , " " r " , ........ i
, ,__., ............, ....... I .. .I ', .I, . i.i _1, ,, .... 1 I .i, .i .I--;"-'r,..........I ,, ' , ' ' ' ' ' ' '1 ,; • , ,l' i ! i I I l " l(_G_C-q , ......... , • l , , . • _ . •
,-.t................. !..' ! :-,.U,..,i""i._i • • i..L.I.... i.-4-1; I.,,,-i , i-.. ---, ,I• , .. , , .'_ • _ , i • _. i , ,' i, ._,._,.. ..... .' ; , ..... i , , • . . , . i _
.oi'"" .......... _-, '. ...... I...... [ ' "": • • i ........... i
• L" "_ I I-2'_;-;;-_i_]rT.i: ,;_:_r_-7ili':"r-:" -_'":_ ' :" -":"'-.............. : .... l
:.!Tril'.r_.i'l!..,]- : : i I ! ! ' . . .'i'" II_'ZI• ; i .. . . : .... : • . •
I'lmi";' "] "_" '; ' " :" ' ' '" i. " ""_.' "' ..... ' ' ".............,.....................'. :!'. "i '; . _' .". .... .;...:.-:-..:: .... :.:I
' I I5i,.i__LJ_.l_ .I,_-4..,! t I,.,I I, I,_L:! i I i i ! I L-J _ I _ I I i t I' I J-_i.L.L.LI J _l i I I 1 I I i I I l,i
........ ...; ';1 'i i. i:.. • "
._". i _,.... :JI .... '.... : • •
., o_.,--_:_, ....... ; _ -" ..... _,i"-; i.: • _'._ ' ! '
(VOI.T_) I-l.. • I ..... i ...... v , , :
ii " .... : " .. ..:..-...-
_'" I ...... I --_" '"'<o'° I2.5". ' •
i, . • ..... • u
,_,.-___. : :. :.:._._;... .......... .(VOLTS) , ,,, . .
• . , , . ." .................-2.$ " , : : . : ..............
I I I_IL'E_;,_......... i........._ ., ......... :..................................I'_...._._+_'L..... _+-,,,............. ; r .......................................p_.:_._..l-..'..;l..".... :... ;.,;......, ..,., ............................. : : : . . i' : • _I!llill';,,*l.;l l,I. I. ;.I .-. "I .i, .:..... _ : . • . . ; . . " i i,l,i,,r'--- -I-.... , • • ."i"
it.I 0 i.Mil'_." '"l .... :'"" "!".'-. : ! " ;''i" : ." ." "': . • ' i " " ' i ............ i-. i(UI-SEC) llli_i-',-l-_'.-!:.',i,i,k,.n- ..,--i .,_. ......... ,i ...... i I ....... "- •, : " : " I ' , .... i .............. .t .....
lllm;,-;f-!--I,-,-P-'l--,..| ....... ".,--h ............ , i ." ._ • .i ...... i .. , ..... ' .... I " ' ..... ' ....... +"1 " " "
I_':,_'.i':::i_',r:;_,;L!:....:._.........._ ....,,.-._:...........: ..; ,_ • i .............. _...,+_-.....I'1.:"."I"1 .-'/:', "r": ": .... "'_ "_"'" ...... 'i..... ' ............... • : , : :.'.-.," . . " I'.;..''1 . • ...
=5 k",'.-',.....;.... , ,,. . ....,i .. , . .,'..'-..-.-, ..... . ....... ,... ,...., .,.... . .-. -_----'..,,...' .... I ." ' ... . -".':..-,;,.I..I • ,.i
!r '_1 ........... •..................... m, ..........._.,_..,,.n ............................................11]..........................................................................................................' .................m....I., ......
I,lt,, i. _ = 1.4 I:)q_= 2
l.._ - o.,l _v_,J
Figure 96. Acquisition and Limit Cycle for _EO = -3°(Analog Run 2!A-3)
:].]_8
1966018034-142
3l_ _: 9-- ...... _-_:--, ..... I-T--_ _-_-..... --:-q .
MODESIGNALI'/OLTS) 0 ._.---.._*-.-,-.--_-- ................. _.... : ....... ._..... r ............. itl" (SEENOTES) ................. :...... : .......................
__ i • ' . _-_--__ --' =--_- -_- -_-;--I--L--;---4-4-:............._-........•-3oo. , ! . ! ', I . I ' ' '
J ' 1 _ , _ _-'-'T-, ,""_ T I l ; t + ,--i _ t [ t t I--_----_ ......
(LeS) ......
, , ' I I t ' ' _ ; , _ t i ' t ' + ' ! P ', i : :
1.67 _: . , i . _ : . "- I --, . .-"-, .... : -_.......... ' "i!--" .-i--"' i--i--.---'-:-i..... : ............4-' : ..:............. -; :, _ : ""._!'--4....., •: "ll.... _ ,i-'_"-}'_i _ ..... il ...... : i i i i " _-" " "_ I ,4l.F--l.-r-7-- T ........ ...-....:......_............ + _ ; ..............
t= 0 " " __' " '--' I i , ' I ................................
+ ii --i'--_-u_...,._'.'; 4 : :-f_-.' _ ' ""r--"_'-';-" i ..'--'-_,"--i-_-_....:.... ,--: - z ..... l . . ....(DEG} -'.,._.-I--L-J-.L=._...... " "., . -, i-_--_---i', i l.... : .... :_ .......... .........:: " _ L ' " : : L " E ' ' -
""'-':'"-r:--""':-'_--"-"T_:-"." f'[ .." i " " : i "'_ "_'"l "'_.......... : "" :-_ ............ . " "................ ' .................. i .....
....' ........ ++i-, !l_.i _..........rTTr-P-T-7_-I r; - T! r i-.m,, iI!r ,+ i li I.;I,,llt,,llllii_' 1 ' I'l , i:..... :, : i , " .".. : ....... :........ T.: ...
i. i
I ..... - __...,.. : . . J..+ r- 7 . •'' _---'--_--_ :i i ; '
(Dt:G/SEC) n ................. i ,-_-J _;.._j _ z_ _. _ ....! ......
• " I.0, ; ;--il' _I.I!I_LLL_!'__1_!111l l +I I__!i!1i l_-_,_....._1!ii!i, ,
{AnCS_CNDS) , !
_'i....i " "'T"T'I,I! ' + ' ',,,LL_,__ !III,!Ii!IiIIIIl_L__iil,ill
o.(VOLTS) . . " "
I I I lil Jill l:i l_lli I ill _ t_;",;_o+ii_L!I I l I I
•_ o........ -,__._./-. . .(VOLTS) ............
.9.$/ I
$ ,I I r i, I I l'l I t I I I___L._L_LJ:..IJ_I_.L_L_I__I._LI.I.I...I I...' J I I ! I '. I.'
A. 0 ....... --
(Ui_ _..') ........
.; :,: i.i " " ..... : :.: .............l@,4t
I_tel 1. _C =' 3.6 DeE/See 2
2, °F " 0.12 Dq/'_ 2
Figure 57. Acquisition and Limit Cycle for _EO = 0(Analog Run 2_A-1)
i
119
1966018034-143
..... _ I -- _--t--"--I
MOD_SIGNAL(VOLTS) 0 ' ' _ ' • J i l-l:-
.... ¼. '-i , : ,_, :i_ , %_:_L]____
I ' ' I ' J I : i [ 4 1 1 : i 4 : , , : i I ! I I ] I I r I,
..... '_ ...... _...... I---i .... i--- _-!--_-- ._t L. ,----L "'
(um) J, ,'-: ' _ : ..........I _ " __-.........._ I -J-_--_ -_..... -_-_-_---'
_ ''iil'l :'l I' 1i 'l ' I t i,.,,_._-_-t--,--rr4.,--L-_-_-LJ-L_--JJ-_-_LL,.__H_LLA_I.._!1II!11 t/_-_:(_-{:,_Li_: ' . : :. .......". ......:........:..;..-::...___._-_-.h- -t-t-_ .-km--h .......... ................. ,......... :' i--'---
,E o' ' :: ''_ "- ...... ; ' "' ....... _ .............................. !"" ;• . --._._11_. . . i . i . . .. i .
• "....... -"_ " ...... :_:-.-:..........;i :._.--".-!i i_n_G_ , ......... : ........ ' ...................... [ . -..i..! J ..... ,......: .................................. _ ............... : ....i .....
l ........... . • : .......................... : I .... -'--- "--.
-'"!.......i, ..................I -.....'....I......... '--.o_l _ I._, ,,-,.,..... ,..'._._i _._ : ,.i.., ......, i i,,, _ i
• .11 .. I i
I • t "_"I i '',i, o J i
(DEG/_EC) i i
1 : "
,o_ l ,..i
"__-_-_ _-+-_,-Y!tT_q!-!-_-__-__*_=!!_, !!!!i _-_
(ARCSECONDS) ' "-"!
•:i:--..::...:..._.:: :t t....:.-: "',_.- :...;._:-_..!- .V._.:....i.......:...-:.---"_ .... '-_ i: _- ......... • i ', _,_i-T ......i---
. .. : ' , .,. ' ... i ! ! _ :_ : .....,.L_,_-__.,..... .. : ; . ..... i : " " ' . ,'_
f"k" "-'-*---!-"i-'--'- ;-i •• : [-.---f :.. x' -'-1"-=1......... ' _ ......................' ' 4 i _ ' _-...-I.--___.-._.1....... I-i_--.-.I-I",--o. ......-..-: .:_..---:-:.:.',.kl:i_-._:,.;m-- ..... . ,:z-_............. ,. , . . -'-:
: -[ ........ ;'_''_']_'--_ . i i-.' " i " , ,, , "''i --_
,---,'V'_TS' ........ !....... _ ....................... t-'l .... , "'-"1"-_"''-'-1""" -'-i-; ........ If ..... l t ....,--I--'""i'-"I...... -t---I..... t" .....i _--i---'--.-, ' .- !-4
-5 --............... :-----_.--"----- I, • .... I......... I-- -4--• i ' ' ' ' '
. "--"1 _ ,S_ON_ I _ i ' -r2.s,. ..- -: _ ....'. i '" : .....:._....... ! i. "-!,'-"--.'.......--!--b=
........................................ t.-:--:: .... ._- .....i.L-:-:-:-.. :i.... _ , .--. ,i i
.... :'--'-r- I-; "_-;--I-_
o 'Xi,*-"" +:, "!" . .i..
(VOLTS) "1.. I........ 'F' I" ,.............
.... l- i..... ! ........ '.,., , : ................... =[_ :I- • ' / ' ' I !! , ! ' I _ ,_;5[_-T_-_-'l-_.-r-:._-__-_-_-: ! ! : i i ' i _ ..... . ' i _:'
'......................... ' "_ ' I "'" ' ..... r-'--*"" _"
• ,_;.......I ..... i-• • -r.q--.!-.,.4......... :----_ .i
bl 0 ...... -- -"'" ....... " ...... "--:_--_" --- h_ J'-I- ........ "--F":'= l....... =, -- •)•"i •"_.... i -."'- 'i(I.B-$E:) .... _'i--'-_'_-I -'-k...... t-'.'f--...... .i:.i.-.--i....d-..._..1._..+_.1_i_.1_,,= !
........................ __-_" ,"!_.,--_"k-.- '.'...T
Noi'et I. _'C= 3.6 Dq/S_ 22. aF = 22,_ AmSeco_h i
!
Figure 58. Acquisition and Limit Cycle for _F = 0.06 Ideg/sec 2 (Analog Run ±.IA-1).,
]2O
1966018034-144
.; ......... ! .................
-!, !.' .- TTr.-T -:,-_i; .W!-.-_-_._.
MODESIGNAL_:)LfS) 0 . ' . ._.... "i ...... :' _....... '._1"(.%_ENOTES} ............... : " " .......
' I : _I ' 1 ........ _ ..............; ...... : _.... i :" ....." " , .... :....... '. i :'":'-'. ............ :........... "_
............ . .... i...._...., m :...................I I
-s .......4....................l ........................ l ................................. ; : ..... ; ,. ......... ;,. : ................................. ! ......."_ ........I ....... s....:...' • • ; .... I --.'I-......... i ..........................................
I " "" " _ !':'':" ":'--'" i ", ........ i ......... " ............................'-i • "';......... .,----..i- ...... ,":'! ....... ! .'" .... _ "" .....................
{I.1_ ., .............;.., ._ ............:..! ..L.........;. '._i .................:.L:'........"_-=- �( è'.......................-.-i ...... :- =.-I. "_-.!. -- -:. I_-_-,..-=.--..'_...."-i'_ ....... = ..........
]"_" i" ' s-, -.-I-_-_.... ; ...... _-.. : ......................... ,_ . !..... s...._.... I...,. I... : . ' , ...............
__ ..-I I1,67 """':.......... "_.......... _ ..... "_............:, ., , -.--i-, ....... _...'..I....i...... :....... _--:,.-..-.- ......... '.. i,".... "" "
'-...... "... I..... .: ..:: .. : ; . . : I I. • ... i "_ ..... i'" " ........... i-':_-_-...-_._.,,,,,---4._... ��,.L:..: .... _ .... . :. :":.." ". :: ..... -..... i:
,,._.._.!..-i-.-.:,-J_-.,_i-:-_-..q. !.._......i ..... :"; ........ ; ..... : ............... ' ....._I_ b ____.=__._.., ==I .... "I==_""""_ ]- ..... i I I r. , . , .= . .. _,.:..= =.:.=..j.. :: : .. , : : • . . .
... i i . .p......J..,i ...... i-._ ...... ' .........(D F.G) : i • ' I ...... I ....................... ••_='-_'.""_"!" "" "=i--J""_" "' "J....... '""' ""I" l" '-1",":-"""" ' ............... % .-I ...... ' • • -: " ' : • :'" " I : i I • :'i. , • •
I@, ":.":'_ i 'll: : ! ; -,'; / :' I "_n'_._ :',.. "._=.... '. " . . ___'." ......... _ !__ "'_"-'; • , -" ", ," : . • ,:-" .; i ....... _'.',, "_ s-'_ -I r'" :.... . • •
-1 _| _'-:-'-...:h. :' .I........... L..- _ ,J...r _r ............ .... i ..... i ............................ i_: ...... ,...................., • I . • • •I
_J i ',r-_i ,- I ! : I _.,-.01 ,r:, "": "...... I , :........ :'..'1"-"1'.."_'" 1--' I_ ';'1'=............. ;..................... , , ............. T ...........................
i:N':_"FL:";"""j J" -i', 4' " i ""j'| i.._..il:|." :'i : .J"" "|.i_'..| :':K,::':.:|'::::: :. -' :L ;.... ' : I "":" " " " , ,....... ,.,...,__,._+,.;L._.._........L..,...,..............................................
-:"....'-' .....;!.,..:..,,,:.,.... ..........._...................,,.........,,......... , ,,,., , ,.,..,..o,,.,'.....i.............. m ,.[Ir.',,,........ ',r'-,,,,"•":' • ,.-'_ .............. 'l "_-'; "'_" ' "_." '1_ . '" _i'D .... i.'_[1 ....._°/_ ,:!,,:.!:.:.-,:._::---_.:_...... _' ,:_.i..._;t ...__,iJ• _.._. _d......' ..ii.;I.:;_"_....-.il.....'"""!"":""' ,_-_"i*_;_'i:.._']!_- ...'-Ij.; :-.":,..:,....:-' ":..,............':..........i......:-:.".........,-.;........... ,• .. I .. I :1:"" _""_="J_" . i. -_ • ._._.-4- _ ..... :... J._ . f.... .: .I . " .' _.. • : .,,4.=-:....." .......r ",...........,___,,...-,::.... ,., , , _ , , =_+.01 - . . • • . ". ....... .................. r'-.-'"; ......_ .....:................
.2.. i .. ' i i . . : i . I_.. ; - i ' • • ' : J • ! ,: ' ,, I • • "_:_:,:",,-:-:l-_.-:!:,.:_-.:-.:_'.,Fi::i,i:1-q_:',T..[_ii.",........:-..!.:I:'-::!:,:._-:.:.::::i:_':..:.r.: '::.......: ;:...-....:"T. :-: :-!_'P:_"-'"t"=' ' "!' -"....-_'"._."..-i"_..t-; ,-.c--e..-I-. i- ._ -, '. -' .:" I i ....... , : ........ : " .................._.i_i:. _ ..=::-.:.-'..,..... '.." "'" I " " ' : '_.i.._..',,,',,',,=..=l'r_,,'.'.,ll"_'.ii,'l_!'',.' :' i_r-r :- "1"- - ", ; , , .... , .....
0 _i:i..=_..'h'_l'.-_--_._._'_"_J_J_,___'#.'_._.""h":'_Y'! "!iJ'_";-_"_':= ="_4_ "': .- L'" "'=. :: :'........ , . I . ! . :..............................
' .... "•,,,-,,.,-_: .. - ........... . I I ." "1....... =t-.-I-. =-'-- '.i-.4..--]---.-._--i-' _ ....... I- I ................................... _ .........."'2 ......... : .
.... -:--I- :_ "q-.-=:..'.- .-' ..t-._. ....... _ ,.-_-._--.-'.-._ ........... '
,,_-,-...._-J ...._- hr.,.--.+........z._...............: .........:...., ........ , ' " '.::. I :r% ' • I ,
;,. "" ' "" ."':" :'1"" .... r" "1.......... , .......... . ...................................................._.1.........=+_.,...............,',-IT..'-..!; I,..':1,. ..... _ ..... :; ..............I_;-'.-_,-:-"-'""'"_=:..'-::--._.:.:.=_i!.+J......................... :... " ...........Fi!'l]....,......: "- ....... "........_Li...'.->-._ _,.'- ; _--_..'...-" ': _ "'"_.1_... _1"""_"_'." ;4-'.--....i "="..... _" •'.'" " ..... " "" . ": •I_':..,,...... , i--, - =- ,_i _J""';_. •!1. .. .......__-..._..h.. ,.-.T. -:.-r. _-_'_ ....___':-4._."+-"-i,... .............__ . I" .... . :'-':'m""_,: .......................:
O FP'-: ....... ,', .... ; st: _ ...... _ • •.......... . • :el I_._- ................. 4-/--:.-;.-4.-i._ i--;. ; ............ I i..... _ • 1 ......... :. -. ............
L_OLI'$) _= ........ I ; .... " .....I I i ' .-, - t- ....... " • -•-:'-,"4"....:.:.-_......_ "-;.-i-.:-"......... : " .1!"..... i"" ''' ' ........ : ..' ........._-F, ....................,.......,.......... ., , . i ._,-....,....:....:;,_.... ! _.:.;.,.. +.::...;,.,-l,..,.-',;,.:::1:::::-.,,.;:i::.:i-:.::::J.:r.....i..:. :::::.•.:..:.... :..
2.5 _--'- "_=-P"I'.----.'","r'-.... ' --,......r......., .... _.......1..... '""" "- ...... '............................................, -...--_ ................................ i.._.' ........... _......... . , . ............ •t_ ....... =,,.t:-_-:" ...,'::._:, ...... • t" , ,;-_,-:,: l-7",_,izr:,:'i-T,:!,;i_7;I,,+,Ioi....,,, _...._.............. :-,, : :::_..'.'4-_..'._:"i._.' 4-,:i_ _..._..I-i-'-t."-_-'i'_._.._._-i-.-.;..............•....._-: ...........• • • --. • • • :._: . . .._._.. .4......_"" .... _..d;i_illi._._ ...s ............ L;..-_..:.._ .: .:.-__.. ..J _..:. ? __ . _ . . _ _ _ _._
. v =._.:.,..'_._..'.j"_'":"....-_--/-,...'""==.:.,'_='"-., .:.'"==:_.: .:;:'-'_|'=J"_"4"'=: ...,.. . .%::......... . _-.............. ; ...... " ..........",.. _!. ,_ _-_-_ ..........- ..........................(YOLTS) _;...p..._..:... ,.. :...,'._ .._."" = -+ "l,.,.._...,_._..._.. "'--"_-.','_.'' ' -," '"l"'r'.........! ..............,"....... r"" "_............
_!"";"""I"1"'! • t- '. I "i".L.;.": .... .""1"","" "i "!.".......................2" ___m._.._-._..,._,._-.,:.............. _ .4.--i...-..,_..,.._........ ,-...,..-_.................................................
"'" : . ' " ' ' i :.! • i,_'___...... '. .... ' _, - _.. :.! ...... I .•'.i-,......_. ;_....F.._i.-_-3C_.-'Z..'TI_"--F......"...... --'.-"..................._'" '" """ " " " 'i_ " ' I.... " "
•I --:.'.'4 ......... 4"" _ .--II-rlP"l --I_ : i--I'"-I. "1_'_="1 "1"1".-- "",'4" ".'-- --...'. I ' ...... . _ ......""--_'1-- -- '----:-- '_'_t'_=" '4"--" " -I'_","l'--'i,-_r--,'"J "" --4-- ...... "' .................... •.;,.t..4.__,...._..4 , ,. .... k,--_,.._--.------
_, _ ,-__-_'?:'i:-;-;r-',;,7:;:' . : :: ::.....:....(LI4EC) |" • .......... _ _4 .-r.i.... i_:i "1_,t_:44 - ..,:._14ik....;-........ ,..................... ,........ I........
' • ............. :;.,'h;"i ',=t'ah_"_li_. _."1 r "L'_I_:_F. I1:11_........................ _"....... 4.. i .....i ...... .... I.'-;1=,__1_.='';.4........'_"'"_..... _........"=;'_:"""";;"" ' """" "" -t-:;I-........., ,'_'-';"'...... " "'-w_'r:..""J_".'l_',:I'-;'...,........,; .......,......I__..',....._. ,,..__,,_................. •
4 ,_1 . . I......................................................._...........................................................................................................................................................
Nm, I. "C " S,_D_A_ 2S. ,p • 0.120qV'h,__
Figure 99. AcquisLtion and Limit Cycle for _TF = 3.0arc sec(Analog_un2_A-Z)
121
1966018034-145
Table ]6
ANALOG STHULATIOI_ SACS LIMITCYCLE CHA_AC_ERISTICS
(Wi_ >_)_t..Delayed Feedback)
Switcbing Low Max Max
Threshold T.brust Peak-to-Peak Average Vehicle AnalogLevel Accelerat ion Amp!i-[ude Period Rate Run
__(deg/seo2) (arcsec/se i
+22,5 0 12 30.0 4 ,,35 18,0 21A2
0.06 37°0 i0°:I 9°0 15A
+10°0 O°12 9.66 -93 18o4 25A1
o°o6 12°3 5o 03 9o7 26A]
The three-axis simalator limit cycle rates a.re consistently higher
and limit cycle periods consistently lower than those obtained in the analog sim-
ulationo Based on nomina.t para_eter values, the rate amplitude is not highly'
sensitive to small variations in threshold in the SACS° Rate amplitude is sen-
sitive to acce.leration, but it is unlikely that acce.Kerations would differ con-
sistently in the same direction from one simulation to the other° It is rel-
atively insensitive to small variations in derived ra.te gain about the nominal
(cf_ Reference i, Section 7)° Sensitivity to valve trigger hysteresis is rel-
atively small° However, the limit cycle rate amplitude is highly sensitive to
the effective cumulative lag in the system° The effective cumulative lag varies
directly with valve dropout time, fine sen_:o_.exponential lag(s), and derived
rate circuit exponential, lagso The effective cumulative lag in the analog s_r.-
ulation is of the order of 70 ms and was so established to duplicate lag char-
a.cteristics of the FACS system° Substantially greaoer lags womLd have to be
introduced into the analog simulation to duplicate, the l_.mite cycle rates and
pel-."-:_seen on the three-axis simulator°
122
1966018034-146
4 °5°8 DELAYED FE_.DBACK - PRELIFIINARY INVESTIGATION
A series of 3-axis s_r_ulator tests was conducted to evaluate the
effe _ of deJayed feedback on SACS operation° An adjustment of paramete_s was
achieved which produced a significant impro_rement in SACS operation° However,
further improvement is considered possib!e and work is uzderway to realize the
fall potential of this technique° The findings shown _lerein are then considered
prel_nninary.
The objective of t_is modification was �¤the SACS limit
cycle characteristics by reducing body rate_ The _elayed feedback provides a
relatively sJ_Jple form of jet palse-width contro]o Figure 60 shows the imple-
mentation° It may be seen that a voltage occuzr_ngat either va]ve trigger will
be fed back through a delay circuit and summed with t.heso_ r sensor error vci_-
age° The sign of the feedback voltage is selected so that it opposes the volt-
age which initially produced trigger action_ The effect desired is to proauce
more rapid valve _urn-offo By proper adjustment of the feedback circait param-
eters, the minimum jet-on time may be substantially shortened and une body
rates thereby reduced°
Figure 60 also shows the parameter values used during _ sts on
the three-axis simulator° It may be noted that the transfer fuocr_ion for feed-
back from the clockwise valve trigger is more complex than its counterpart
counter-cloc_^'ise circuit° This difference was not specificalily desired but
rather resulte# from the manner in which the circuit was set Up o Further in-
vestigations now underway utilize a simple first-order lag term on each side°
Nevertheless, using the i:nplementation and parameter values shown,
an encouraging improvement in SACS limit cycle was achieved° Simulator tests
were run to domonstrate this improvement and to establish that no detrimental
effect on acquisition performance resul_edo With the low-tbrast valve thres-/ 2
hold set at + ]0 arc seconds, low-level acceleration at Oo12 deg/sec , aud
high-level acceleration at 5.6 deg/sec 2, it was observed that:
Maximum limit cycle peak-to-peak amplitude _as 19 arc SeCo
o Maximum body rate was 35 arc sec/seco
o Average acquisition time (8 acquisitions) was 2.6 seconds_
/.123
1966018034-147
_i.lm
I I
_ - " -" = I:::I'PI
:- U
I r_
I
" " :_" - :: "_ -- I_ I . "_- II II II- II: II (_1
= l:Il:I _C)
"""-_'- -:_--_:-"_-__="...... _'_;'Ii_--._-'--_ ,-, =
.--:_:.--._ _: _,_o . :-: - . -. _ _ o ® ----.,
.,-_-_"v:_:-,:_":_:-C-" ""'- '"J_ '_-_ -_" _ o " -0- .Ill"_ _- _ '0 "_
.-:.:_:.:-"-°'::_.-_.1:-/:-___.. -,_:.__,--:-'..:- o %.- . . , ,
1966018034-148
The extent of irqprcvement is ;erhaps best seen by noting that the
system without delayed feedback produced maxin:um limit cycle body r_tes of 145
arc sec/sec under" these conditions. It is also observed That acquisition times
I+ rlwere uctualiy shorter with feedback installed a±_h._,igh _esting was limited and
this may be coincidental.
It becomes difficult now to define the "period '_of limit cycle.
The delayed feedback causes the character of limit cycle to become much less
periodic. This may be seen in Figure 61 which reproduces a portior of three-
axis sim,Llator run 56 showing acquisition and limit +zcle behavior. The traces
labeled "low-thrust valve" a.u-tual±y-" monitor the valve drivers o Thus a very short
pulse may not result in valve opening° It appears, by correlating the valve
trace and the sensor output trace_ timt much of the activity at the driver did
not produce valve opening_ In such cases the feedback removes the turn-on sig-
nal before valve _ction can occur° It can also be seen that the occ,lrance of
body rates as high as the quoted 35 arc sec/sec maximum is restricted to sho1_cl
t:nne intervals and is associated with CCW jet a:_tion.. Generally, bod[v _ates are
substantially lower.
These results have led to continued exauv_inaLion of the delayed
feedback techr,ique. Since improvement so substantial can be gained by use of
simple circuits, delayed feedback will also be incorporated in the IACS control
channels.
J2
Q
125
+h
1966018034-149
, )' ° ! ' )° _" ) _ o _ _ _) w .
II _. I " 'J-L_ ' ' ' * ;" )t _ 4 o¢-- 1 ' )_ I l k i _ ' l t"dLJ I o : _' .' 4#_F ) - -L_._=._II ,"
rq,_l ]-[ , _ -I;-I.-1..?-1 ' , 1-r--ti' _ 1,,_ +_ti_ ,_ , t_I-tLU_,:_
I " f , . ....; ..'t..... ! I J ' ' ._ ' ., " "= "-
• - • I .... ......... "::_'" -. .. I : . . _ ...... ',.._:-'- ...... _. • I.
l _ I _ ...... I l I _ l _ F _ l llt _ l l _/ l l l _ l_l_l
........... _ ............ _ ......... ; ...... :l _ 1
l l _l l " l i _ II l l l l I _ l )l l _ l :.,." _. _ "i. i 1.__1 .... _l .... _ _llll _l_ _
=_ I; _ I l l _ l _ l _ l I l _ " l I _ .......... _ll_ I _ m_ I i _ Im_ _ l_l_
..... _ l l _ _ t ....... _ .............
J :: . .; = ._- . ..-._
" )I .......... _ ............ _ ........... (ml ............ l m m "l _ ..... 1 ........... _) _" m _ lm)l" _ _
l l -- I '_ I ................. I ......... _ " .......... I'' _'_=I----' ......... _: l ..... _ :'':_ _ _
" _: .... III ": :'- I " ' " '') " "[" :'-'I" I : . " I " ll; _ _ . ' l lI. TM :_:_P _:_'_ TM ._ _I_ _
" ] l ) .............. ] ..... _ l : _ _ . " I" . l l ) : l. : " :: ": 1_': ..... T_'_ _" _ ) ) _
......... Y " " [ " 1 - ;t :----'-_-l l _ 4 l_ :l . ' _ " t
' r :.".l l _ : l " _lll l ...... i l l l: ll•"';-':"":=............. "L" i "_
...... ._ rj)
• -: _ ,_L I I I : I I I ........... _ _• _• I _A i,.__.,,, o,
• i. " " ._
! : ._....... I-
l
ll........ i "..... _-o ._ ;_ :_ ; ,4t_ i " L. " 0_
il • [ " " _ l l l • . l" " l
z_6
1966018034-150
Se,._ion 5
SYST_4 C;_/NGES (P}L_SE i])
Af, the con<iusion cf +,hree-_;_i_ ,_:hr.,a[_.tortests_ a, review of find--
ings was made and agreement tea:bed cm +,,t_ee_seo_i;_]_ features cf t}_,,eprototype
FACS.
9 .L OPTIONAL _EA.TU]_S ,-$£LECTION OF ALTERI_ATE
The breadboard FA.CS was designed t,e permit evaluation of several
cptional featu_'eSo A determination of the preferred fe_<ures was ran.dean_ <.he
prototype FACS will r-eflec_ this determi[miion &s foL!cws;
Bi-level rate gain will be used iu The IACS pitch _nd 'yawchanne Is.
Dual detector's, one fcr l&,TS captu_e indicat, icn _.nd cne fc_
SACS enabling_ will. be ._sed in the pitch and yaw <_a.rmelso
• Roll r_,,tegein co_ange will ovcur a.t the cc_pietion of roll
capture and she lower- rat,e gt.in wil[_ be re_ained therea.f+er_
• The rate-only control mode in piV.(-t:_nd 'yaw wit.' be effect Lye
until, z_ol.Lc_ptosoe is -ompleT,.e. Pcaition plus rate _on-Lrclwill oe rer,_ined thereafter,
9.2 DESIGN CHANGES
Design changes to FACS subassemblies will be carried out dur-iog
Phase II. These changes are listed below_
• Roll Stabilized Platform.
(!) The servo amplifier will be replaced to provide a bet_er
match of amplifier to motor.
(2) T'he platfom will be modified to provide an 9_iprovedstatic ba,lance _
(.5) T_he housing will be modified to incorporate seals°
1966018034-151
• Static Inverter
(i) The integral shor_, circuit protection will be removedand provision made for replacement, wJth external shoztcircuit protection.
(2) Design changes will be made to increase efficiency.
• IACS Control Unit
(i) Gyro position signal limiters used in the breadboardFACS pitch and yaw channels will be retained and sim-ilar provision will be examined for the roll channel+
(2) Delayed feedback circuits will be incoz-po_'_ed in theroll_ pitch and yaw channels°
(3) Series diodes at the despin and CW roll valve wiRl beeliminated,
(4) The amplifier provided for the single-level-detectoroption will be eliminated+
(5) Capture level detector triggers will be redesigned tosubstitute f_ed resistors for the pctenticmeters Z_R4_
Z_R5_ and ZR6o
(6) Slave roll triggers will be redesigned to substit'J+tefixed resistors for the potentiometers Z/{14and ZP_5.
• SACS Control Unit
(i) An improved version of the aelayed-feedback circuitswill be incorporated.
Programmer
(i) Based on optimization studies to be conducted duringPhase II_ the VTT circuits will be modified to the"current-only" mode.
(2) The VTT compensation for inner gimbal lag angles willbe extended in range+
• Telemetr_ Signal Conditioner
(i) Isolation circuits shall be incorporated as necessaryto permit FACS calibration without the conditionerinstalled.
128
1966018034-152
Junction Box
(I) Series diodes will be removed from the valve circuits.
(2) Umbilical and test cable requiraments will be re-examine d.
C-round Support E_[uipmen_
(i) The provision for 3-wire-synchro offset caging will beretained and the provision for 2-wire offset caging. 0
w±ll be eliminated. Offset requirements become + 20in pitch and iFaw,+ 90° in roilo
(2) All cases of false indications will be eliminated from
the console display.
(3) Voltmeters will be incorporated in the console display.
129
1966018034-153
Section 6
CONCLUSIONS AND RECG_NEN_ITIONS
Test of the Fine Attitude Control System has demonstrated perfo_1-
ance meeting or exceeding all requirements:
(i) Pointing accuracy better than + i0 arc seconds was achieved.
(2) Target acquisition times better than i0 seconds weredemonstrated.
(3) IACS-only operation was accomplished without degradationof performance.
(4) Programming capability suited to m_itiple stellar targetuse is provided°
(5_ Low rate limit cycle capability was achieved by use ofdelayed-feedback techniques.
(6) Gyro offset caging provisions met range and accuracyrequirements.
(7) The FACS and a_l subassemblies successfully underwent spe-cified environmental tests.
(8) Ground support equipmert compatib_lit7 was established bybench test and three-axis simulator test.
Based on this succ_ssful demonstration of acceptability_ follow-on
develolment of FACS prototype and flight units is recommended.
130
1966018034-154
References
i. Report SGC 742R-5, "Fine kttitude Control System - Phase I, Analog Simula-Zion Report," December 1964.
2. NASA-GSFC Stabilization and Controls Branch _Report 108, "A Single-_misAnalog Simulation of the Aerobee FACS: Review of Space-General CorporationWork and Description of GSFC Work," February 18, 1965.
3. Report SGC 742-TR1, "Optimization of Variable-T_me Torquing System forAerobee FACS_" 16 March 196_.
_. Report SGC 2_J_-8, "Fine-Attltude Control System - Design Study ProgramFinal Report," July 196_.
9. NASA-GSFC Stabilization and Control Branch Report No. 66; "A Study of theAerobee 150 IACS/SACS Control System"; April 2, 1963.
6. NASA-GSFC Stabilization and Control Branch Report No. 96; "Design, Testing,and Evaluation of the Aerobee FACS Breadboard Sun Sensor"; July 29, 1964.
131
1966018034-155