tmt.opt.pre.07.046.drf01 14 september 2007 1 requirements and conceptual design of m3 system ben...
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14 September 2007 1TMT.OPT.PRE.07.046.DRF01
Requirements and Conceptual Design of M3 System
Ben PlattMyung ChoMark Sirota
14 September
14 September 2007 2TMT.OPT.PRE.07.046.DRF01
Outline
Ben Platt – Overview and System Requirements
Myung Cho – Modeling Conceptual Mirror Support Design
Mark Sirota – M3S Control Systems Overview
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Tertiary Mirror System (M3S) Overview and System Requirements
Ben Platt
14 September 2007
14 September 2007 4TMT.OPT.PRE.07.046.DRF01
Outline
M3 System Decomposition
External Interfaces
M3S Overview
External Interfaces
M3 System Requirements
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M3 System Decomposition
M3 System (M3S)M3 Cell Assembly (M3CA)
– M3 Mirror (M3M) {blank and polishing}– M3 Supports (M3SS) {actuators, load cells, cabling}– M3 Cell (M3C) {cell structure, trunnions}– M3 Control System - Cell (M3CSC) {electronics, software, sensors}
M3 Positioner Assembly (M3PA)– M3 Rotator (M3R) {Rotator Structure, Rotator Drive(s), Rotator Bearing,
Countermass}– M3 Tilt Mechanism (M3T) {Tilt Structure, Tilt Actuator, Tilt Bearings}– M3 Cable Wrap (M3CW)– M3 Control System - Positioner (M3CSP) {electronics, software,
sensors}
M3 Interface Panel (M3I) {electrical/fluid interface with Telescope Structure}
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Structure (TMT.TEL.STR)
Optical Cleaning Systems
(TMT.TEL.OPT.CLN)
Optical Coating System (TMT.TEL.OPT.COAT)
Telescope Safety System
(TMT.TEL.CONT.TSS )
Power, Lighting, and Grounding
(TMT.TEL.CONT.POWR)
Optics Handling Equipment
(TMT.TEL.OPT.HNDL)
M3(TMT.TEL.OPT.M3)
Engineering Sensors(TMT.TEL.CONT.ESEN)
Test Instruments(TMT.TEL.OPT.TINS)
Telescope Control System
(TMT.TEL.CONT.TCS)
ICD-STR-M3
ICD-M3-CLN
ICD-M3-COAT
ICD-M3-TINS
ICD-M3-HNDLICD-M3-TCS
ICD-M3-TSS
ICD-M3-ESEN
ICD-M3-POWR
M1 (TMT.OPT.M1)
ICD-M1-M3
Summit Facilities (TMT.FAC.INF.SUM)
ICD-SUM-M3
Enclosure CraneDimension and Clearances
M3S External Interfaces
Draft copies of the ICDs will be made available for this study.
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M3S Top Level Requirements
Provide 2 DOF articulation for alignment & to steer beam onto instrument
Provide rapid slew of M2 Mirror to switch beam between instruments
Provide smooth tracking to maintain beam on instrument, during observing
Maintain M3 Mirror figure in the face of changes in gravitational and temperature fields
M2CA
M2PA
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M3 Cell Assembly (M3CA)
The M3CA consist of the Cell, Mirror and Mirror Support System.
M3CA
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M3 Mirror Blank Requirements
Mirror Material:– low expansion glass
or grass ceramic flat mirror
M3 configuration:– Flat solid elliptical
mirror, CA = 3.470 m X 2.454 m
Blank Shape: – Plano – Plano
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M3M - Polish
All figure requirements are with the mirror in the M3CA.
The figure requirement is completely described with a normalized Structure Function based on a Kolmogorov atmosphere, with tip/tilt removed.
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35
0
230
2
500
r
mnmA
Where:
D(x) is the structure function and is in units of (nm)2
A = Leading coefficient = 211015
B = High frequency errors (surface roughness) = 2 nm
x = Separation between point pairs, similar to spatial frequency.
d = Diameter of beam footprint = 1.33 m
r0 = Fried’s parameter = 3.66 m
2323
5
42.375.136.10 Bd
x
d
x
d
xAxD
Where:
M3S Structure Function
Over any beam footprint d = 1.33m
M3 SQRT(D(x))
0
50
100
150
200
250
300
0.000 0.200 0.400 0.600 0.800 1.000
x/d
Sq
ua
re r
oo
t o
f D
(x),
(n
m)
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Figure Parameters Derived from Structure Function
Parameters derived from Structure Function– RMS WFE = 168 nm– Surface Slope Error:
P-V = 1.69 µrad
RMS = 0.47 µrad
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M3 Cell (M3C)
The tertiary mirror cell supports the M3M and M3SS. It also provides a reaction base for the active mirror supports.
Supports weight of mirror and mirror supports in any orientation of the telescope.
Functions as handling device for the tertiary mirror.
Stiffness shall be sufficient to support a M3S first resonant frequency of > 12 Hz.
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M3 Support System (M3SS)Performance Prediction of NAOA Conceptual
Design
Myung Cho
14 September 2007 15TMT.OPT.PRE.07.046.DRF01
Conceptual Design Parameters
Mirror – Flat solid elliptical mirror– Mirror thickness: 100 mm– Mirror mass: 2000 kg or less
Mirror support system– Elliptical patterns (hexa-polar)– Tri-axial support concept
60 Axial support (passive/active),
60 Lateral support (passive in X &Y)
Mirror substrate chosen to be solid flat 100 mm thick, to produce smooth print-through bumps that can be corrected by adaptive optics
60 hexa-polar support pattern
X
Y
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M3 Support Concepts (Tri-axial )
M3 Support concept design (presented at M3 CoDR) with– Tri-axial support units that apply force vectors that intersect at the
mid-plane of the mirror– These were linked by hydraulic whiffle trees into six sectors that
provide support and definition in six DOF’s
load cell
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Nominal support location (radial position):R1: 17%
R2: 40%
R3: 63%
R4: 86%
Support print-through in Z:– P-V surface: 58 nm– RMS surface: 11 nm
(entire surface)– Axial support in 2 groups:
218~220 N on R1 (inner most)
276~306 N on R2-R4
(note) support forces in each group are not the same
Axial support performance(mirror face up; gravity in local Z)
Support print-through Support forces
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M3 Lateral Support
Surface error: gravity in -Y direction
9 nm P-V
1 nm RMS
Gravity
Gravity
Surface error: gravity in X direction
8 nm P-V
1 nm RMS
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M3 Dynamic Performance
Natural frequencies and mode shapes (free-free)*
*First 10 mirror bending mode shapes are similar to low order Zernike polynomials
Mirror mass = 1750 Kg in the model
mode frequency mode shapeID (hz)
1 60.3 0 astigmatism 2 70.9 45 astigmatism 3 132.9 focus4 147.1 0 trefoil5 155.9 30 trefoil6 242.5 0 coma7 262.5 0 quadfoil8 267.9 45 quadfoil9 328.5 90 coma
10 388.1 2nd coma
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Active support performance
M3 active supports can correct low order aberrationsFirst 10 mirror bending modes (natural modes) were modeled noise-free for a perfect system to determine
– Residual RMS surface error from Reference surface RMS of 1000 nm– Maximum actuator force to correct Reference surface– Gain (Reference RMS ÷ residual RMS)
RMS based on the entire optical surface
Reference Active Optics Correctionmode P-V rms P-V rms Fmax Gain
ID (nm) (nm) (nm) (nm) (N) 1 3998 1000 2.4 0.3 9.33 38972 4583 1000 2.5 0.3 12.05 34573 4138 1000 7.3 1.1 40.48 8804 5582 1000 18.0 1.8 56.04 5575 4988 1000 14.2 1.6 60.90 6086 4165 1000 37.4 6.2 113.01 1627 5212 1000 56.4 6.3 173.47 1598 5648 1000 52.0 5.7 190.30 1749 4963 1000 55.8 7.5 226.02 133
10 4211 1000 139.8 23.4 438.25 43
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M3 Control System – Cell (M3CSC)
Mark Sirota
14 September 2007 22TMT.OPT.PRE.07.046.DRF01
M3 Control System-Cell
Summary Description & Requirements– The M3 Control System–Cell (M3CSC) provides local control for the M3 Cell
Assembly (M3CA). – The M3CSC is independent and separate from the M3 Control System-Positioner
(M3CSP).– The primary external M3CSC control interface is with the Telescope Control System
(TCS) via a single Ethernet connection. – The M3CSC will meet all performance requirements over the following conditions.
Zenith angles between 0 and 65 degrees
Zenith angle rates up to 30 arcseconds/seconds
Temperatures between 2 and 15 degrees C
– The M3CSC will be capable of maintaining the M3 mirror figure without requiring zenith angle or temperature data from the TCS at rates any faster than once every 100 seconds.
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M3 Control System-Cell
Summary Description & Requirements– The M3 Mirror shape will settle to its final shape within 15 seconds of any
change of Zenith Angle between 0 and 65 degrees.– “Cell Control” look up table (LUT)
Contains the set-points for each force actuator as a function of zenith angle and temperature.
The values contained in the Cell Control LUT are provided by the TCS.
Initial values for the Cell Control LUT will be developed during optical lab testing and supplied by the M3CA vendor.
Zenith angle and temperature are provided to the M3CSC by the TCS at a constant rate of ~ 0.1 Hz.
The M3CA won’t require complete calibration of the Cell Control LUT more frequently than once per year. Bias only corrections (zero point corrections) to the LUT will be allowed on a monthly time scale.
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M3 Control System - Cell
Summary Description & Requirements– Calibration and Diagnostics
The M3CSC will provide a telemetry stream that consists of M3CSC parameters such as currents, sensor values, etc.
The M3CSC will include a diagnostic and calibration mode which supports
– control of individual actuators and the reading of individual sensors.– support the on-sky measurement of individual actuator influence functions
The M3CSC will have the capability of receiving and executing M3 Support command offsets from the TCS at rates up to once per second. (This will be used to gather data required to build a new Cell Control LUT)
– InterfacesControl and data transmission between the TCS and M3CSC will be via a single Ethernet connection.
All control, power, utility, utility interlocks, engineering sensor, and local control interfaces are via the M3 Interface Panel.
– E-Stop, Safety, and Fault Handling and Alarms
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M3 Control System - Cell
M3
SUPPORTS
M3Cell
ControlProcessor
&Amplifiers
Cell Control Delta Forces
Zenith AngleTemperature
MIRROR
M3 CELL
Actuator Commands
Sensor MeasurementsTelemetry
Alarms and Faults
Control Commands
M3 Control System_Cell
M3 Interface Panel
E-Stop
Power
Coolant
M3 CableWrap
Power(if required)
Coolant(if required)
Local ControlEthernet Port
M3 Control System - Cell Functional Block Diagram
Σ
M3
MIRROR
CellControl
LUT(Forces)
(non volatile)
Engineering Sensors
Dat
a
Data
Cell Control LUTBuild and
Management
Cell Contol LUT Data
TelescopeControlSystem
TCS M3CS_Cell Adaptor
DataManagement
System
UtilityInterlocks
M3 Cell Assembly
ShapeMeasurements
Alignment &PhasingSystem
Shape to ForceTransformation
stars
Data
.
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Continue with Overview and System Requirements
Ben Platt
14 September 2007 27TMT.OPT.PRE.07.046.DRF01
M3 Positioner Assembly (M3PA)
The Positioner will articulate the M3CA in two (2) axes.
Points the science beam coming from M2M to science instruments, located at various positions on the Nasmyth Platform.
Tracks to keep the science beam positioned properly on a given science instrument, while observing through changing telescope angles.
Slews to new target and/or instrument.
The stiffness of the positioner shall be such that when carrying the mass of the M3CA, the first resonant frequency of the M3S is > 12Hz TBC. This shall apply to all possible orientations of the telescope.
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M3PA Top Level Requirements
The tilt mechanism will provide articulation of M3M about the M3T axis, which is in the plane of the Tertiary Mirror optical surface, collinear with the minor axis of the outer elliptical profile of the M3M.
The M3 volume constraint is a 2.2 m diameter cylinder extending from the vertex of M1 a height of 1.5 m and a 3.5 m diameter cylinder extending to the top of the M3S.
3.5 m
2.2 m 1.5 m
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M3PA Top Level Requirements
The M3 Positioner interfaces: – Telescope Structure on the lower end
– M3 Cell Assembly (M3CA) on the upper end. .
A rotator bearing is located on the bottom of the Positioner to provide smooth and accurate rotation of the Tertiary Mirror. This bearing is part of the Positioner.
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M3PA Range of Motion
10 20 30 40 50 60 70
100 20 30 40 50 60 70Zenith Angle (degrees)
Zenith Angle (degrees)
M3 Tilt Trajectories
M3 Rotation Trajectories
0
0
-10
10
20
30R
ota
tion
An
gle
(d
eg
ree
s)
45
40
50
55
60
Tilt
An
gle
(d
eg
ree
s)
Tilt range: 50° +/- 8 °
Rotation range: +/- 180 °
– Must address instruments on both Nasmyth structures
– Additional range required for servicing
Tilt
Rotation
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M3 Positioner – Rotator (M3R)
The M3S azimuth bearing supports the mass of the M3S in all possible orientations of the telescope. It also defines the position of the tertiary mirror (M3) with respect to rotation about the telescope optical axis. The outer diameter of the bearing shall be 2.2 m. The inner diameter shall allow personnel access for maintenance of the M3S.The bearing shall be capable of supporting the mass of the M3M, M3C, M3 Support System (M3SS). Rotator
14 September 2007 32TMT.OPT.PRE.07.046.DRF01
M3 Positioner – Tilt Mechanism (M3T)
The tilt mechanism is a 1-D tilt mechanism and shall rotate about an axis in the plane of the mirror, coincident with the short axis of the ellipse and perpendicular to the optical axis of the telescope.
The M3 tilt mechanism shall have a smooth slew and tracking mode with controlled accelerations to meet the requirements stated in the M3 Control System – Positioner (M3CSP)*.
*See presentation on M3CSP
Tilt Mechanism
14 September 2007 33TMT.OPT.PRE.07.046.DRF01
M3 Cable Wrap (M3CW)
Utility lines (power, cooling, pneumatic, hydraulic (TBC)) as well as signal lines traverse the Interface between the M3PA and the telescope structure.
These lines must be routed through a cable wrap, provided on the M3S, near the Interface, to allow for rotation at this Interface without damage to the lines.
The cable wrap may go on either side of the azimuth bearing but must not block servicing access.
14 September 2007 34TMT.OPT.PRE.07.046.DRF01
M3 Access
Ladder inside M3 tower
– M1 floor extends to inside of M3 tower
– M3 and M1 not shown for clarity in figure
– hoist attachment point for lifting equipment
14 September 2007 35TMT.OPT.PRE.07.046.DRF01
M3 Interface Panel
TMT will provide an interface panel for connecting all cables, wires and hoses.
The interface panel may be located on either side of the rotator bearing or in the tower.
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M3 Control System – Positioner (M3CSP)
Mark Sirota
14 September 2007 37TMT.OPT.PRE.07.046.DRF01
M3 Control System-Positioner
Summary Description & Requirements– The M3 Control System–Positioner (M3CSP) provides local control for the M3
Positioner (M3P). – The M3CSP is independent and separate from the M3 Control System-Cell
(M3CSC).– The primary external M3CSP control interface is with the Telescope Control
System (TCS) via a single Ethernet connection.– The M3CSC will meet all performance requirements over the following
conditions.Zenith angles between 0 and 65 degrees
Zenith angle rates up to 30 arcseconds/seconds
Temperatures between 2 and 15 degrees C
– The M3CSP will receive and execute rotation and tilt position commands from the TCS.
14 September 2007 38TMT.OPT.PRE.07.046.DRF01
M3 Control System - Positioner
Summary Description & Requirements– Calibration and Diagnostics
The M3CSP will provide a telemetry stream that consists of parameters such as currents, sensor values, etc.
The M3CSP will include a diagnostic and calibration mode which supports control of individual actuators and the reading of individual sensors.
– InterfacesControl and data transmission between the TCS and M3CSP will be via a single Ethernet connection.
All control, power, utility, utility interlocks, engineering sensor, and local control interfaces are via the M3 Interface Panel.
– E-Stop, Safety, Fault Handling, Alarms
14 September 2007 39TMT.OPT.PRE.07.046.DRF01
M3 Control System - Positioner
Core performance characteristics– These numbers are representative and will be updated over the next several weeks.
Requirement Value Comment
Travel Range
Tilt +/- 8 degrees
Rotation +/- 180 degreesRepeatability
Tilt 1500 m-arcseconds
Rotation 3000 m-arcseconds
Piston 175 µ-meters RMSDifferential Accuracy
Tilt 200 m-arcseconds RMS
Rotation 200 m-arcseconds RMS
Piston 30 µ-meters peak
Max change in piston with simultaneos tilt and rotation
moves (< 15 arcseonds).Jitter
Tilt 100 m-arcseconds RMS
Rotation 100 m-arcseconds RMS
Piston 5 µ-meters RMS With trend removedTracking Speeds Tilt +/- 5 arcseconds/second Rotation +/-10 arcseconds/secondSlew Time < 2 minutesSettling Time < 10 seconds
Turnarounds can occur(tracking trough zero speed)
over 15 arcseconds
over the full travel range
Command minus M3 actual with trend removed
14 September 2007 40TMT.OPT.PRE.07.046.DRF01
M3 Control System - Positioner
.
M3Rotator/Tilt
ControlProcessor
&AmplifiersM3 Rotator Positions
Rotation & Tilt
Zenith angleTemperature
Telemetry
Alarms and Faults
Control Commands
M3 Control System-Positioner
M3 Interface Panel
E-Stop
PowerCoolant
M3 Cable Wrap
Power(if required)
Coolant(if required)
Local ControlEthernet Port
M3 Control System – Positioner Functional Block DiagramD
ata
AlignmentMeasurements
Data
M3 Positioner Control
stars TCS
TCS M3CS_P Adaptor
APS
DMS
UtilityInterlocks
M3 Positioner Assembly9/5/2007
.
.
M3
TILT
MECHANISM
Limit and Home Switches
Rotator Commands
M3
ROTATORRotator & Tilt Commands
Rotator and Tilt Encoders
Engineering Sensors
Pointing Kernel
Positiondata
Transformation to delta
mechanical angle
Dat
a
Limit Switches