using propulsion system for loss of control prevention and ... · national aeronautics and space...

National Aeronautics and Space Administration

www.nasa.gov

Using Propulsion System for Loss of Control

Prevention and Mitigation

Jonathan S. Litt

2013 PCD Workshop

December 11-12, 2013

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Team members

• Jonathan Litt

• James Liu

• Karl Owen

• Shane Sowers

• OA Guo

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Use of Propulsion for Envelope Protection

• The engines are very powerful actuators for

augmenting the flight control system

• They have a wider operating envelope (altitude,

angle of sideslip, and angle of attack) than traditional

control surfaces of the aircraft

• The pylons used to attach the engines to the plane

are structurally very strong to accommodate the

propulsion system as a flight control effector

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Authority of the engine compared to aircraft

flight envelope

• The yellow arc represents the engine’s operational

range in terms of angle of attack and sideslip

• To investigate envelope protection schemes that

utilize the propulsion system, we need good models

that cover this operating region

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Pilot-in-the-loop testing capability

Flight Simulator

• This is our old system

• It had two throttles, rudder pedals, and a side-stick

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Flight Simulator

• This is our new system

• Installed in March

• FAA certified trainer for built-in aircraft models

(Cessna Skyhawk, Citation, etc.)

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Flight Simulator

• It has a motion base,

• a wrap-around high-definition visual display,

• a Garmin 530 GPS, and

• an Instructor’s station that enables setting weather

conditions (wind, cloud layers, temperature,

precipitation), and aircraft configuration (available

fuel, weight, center of gravity)

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Flight Simulator

• Software is X-Plane

based, which allows

modification and

interfacing with external

systems

• Using the hooks in X-

Plane, the built-in aircraft

models can be replaced

by research simulations

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Transport

Aircraft

Spare

X-Plane

(TCM & C-

MAPSS40K

Master_PC1

Visuals_PC2


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Flight Simulator

• Six programmable overhead switches

• Cockpit instrumentation and throttles

can be customized for different aircraft

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Transport Class Model (TCM)

• Requires two 40,000 lb thrust class engines

• Transport Class Model (TCM) is a NASA-developed

simulation of a 200 passenger commercial jet aircraft

• It is a full size version of the subscale Generic

Transport Model (GTM), which is similar to Airstar,

the NASA Langley testbed

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Transport Simulation

• Large, four engine transport aircraft

• Requires four 40,000 lb thrust class engines

• Highly realistic behavior

• Detailed, complex flight control system

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Commercial Modular Aero-Propulsion

System Simulation (C-MAPSS40k)

• 40,000 lb thrust class engine

• Runs in real time

• Realistic controller

• Actuators are fuel valve, variable stator vanes (VSV),

variable bleed valve (VBV)

• Realistic behavior, including off-nominal

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Updates to C-MAPSS40k

High Angle of Attack Modeling

• Original approach used a

parallel compressor model

to simulate inlet distortion.

• The results were calibrated

using sectored CFD

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Single flow path

P,T

Parallel Compressor Approach

Multiple interacting flow paths

P1,T1

P2, T2 P3, T3 P4, T4

Partial-annulus inlet/fan model

displaying static pressure contours

calculated at zero AOA


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Updates to C-MAPSS40k

High Angle of Attack Modeling

• For simplification and real-

time operation, scale factors

for variables of interest were

determined so that C-

MAPSS40k output matches

parallel compressor results

• Currently, a full annulus CFD

modeling approach is being

used to validate sectored

CFD results, as well as add

fidelity and ability to reach a

larger AOA

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Response of total thrust using various

controllers to increasing AOA (0° to 21 °

from 30 to 90 seconds)

Full annulus CFD approach to

modeling effect of inlet distortion

20 30 40 50 60 70 80 90 1002.4

2.5

2.6

2.7

2.8

2.9x 10

4

To

tal T

hru

st, lb

f

20 30 40 50 60 70 80 90 1001.8

1.9

2

2.1

2.2

2.3x 10

4

Byp

ass T

hru

st, lb

f

Open Loop

Fan Speed Control

EPR Control

20 30 40 50 60 70 80 90 1005600

5800

6000

6200

6400

6600

Co

re T

hru

st, lb

f

Time, s

20 30 40 50 60 70 80 90 1002.4

2.5

2.6

2.7

2.8

2.9x 10

4

To

tal T

hru

st, lb

f

20 30 40 50 60 70 80 90 1001.8

1.9

2

2.1

2.2

2.3x 10

4

Byp

ass T

hru

st, lb

f

Open Loop

Fan Speed Control

EPR Control

20 30 40 50 60 70 80 90 1005600

5800

6000

6200

6400

6600

Co

re T

hru

st, lb

f

Time, s


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Integrated Flight and Propulsion Control (IFPC)

Contract with Pratt & Whitney

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• Developed architecture to integrate propulsion system with flight control to

prevent or mitigate selected loss-of-control scenarios.

• Uses Dynamic Inversion to match the desired response

• Propulsion is only utilized for maneuvering in abnormal situations

High Level Integrated Flight and

Propulsion Control

Addition of engines to typical dynamic

inversion flight control law


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Research Scenarios

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• Have started to look at case of Asiana 214

– Too low and too slow, hit just short of runway, hull loss,

casualties

• Preliminary work shows promise

• Plan to have more details at AIAA SciTech Conference,

January 13-17, 2014, National Harbor, MD


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Summary

• New flight simulator enables better pilot interaction

with the airframe and engine simulations than

previously possible

• High AOA modifications to C-MAPSS40k allow more

realistic modeling of behavior in specific loss of

control situations

• Investigating IFPC and other potential approaches to

envelope protection using the propulsion system

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Thank you

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