Document
National Aeronautics and Space Administration
•
Enhanced Engine Control for Emergency
Operation
Jonathan Litt
NASA Glenn Research Center
MEETING No. 110
AEROSPACE CONTROL AND GUIDANCE
SYSTEMS COMMITTEE
October 11, 2012
www.nasa.gov 1 National Aeronautics and Space Administration
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Overview
• Motivation
• Approach
• Testing Results
• Conclusions and Future Work
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Motivation
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~~~- AfW . - .
~ . . ~ f ~' , It,. .... _-_.- ""' 2003, DHL cargo plane Missile strike caused hydraulics loss and wing damage 2006, Comair Flight 5191, Accidentally attempted takeoff on runway that was too short 2001, AA587 Airbus A300 vertical stabilizer and rudder separated in flight due to excessive rudder input in response to wake turbulence www.nasa.gov 3 National Aeronautics and Space Administration
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Motivation
• UA232, DC-10, Sioux City, Iowa, July 1989
- Uncontained tail engine failure
- Lost all hydraulic systems
- Used two good engines to maneuver and crash land
www.nasa.gov 4 National Aeronautics and Space Administration
Previous Research
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-The Sioux City Accident inspired a NASA flight test program
to investigate the use of the engines for flight control
-This testing identified several problems with using only
throttles for flight control
- weak control moments
- difficulty in damping phugoid and Dutch-roll
oscillations
- coupling between pitch and roll
- sluggish engine response
CAN ENHANCED PROPULSION CONTROL MODES HELP IN THESE SITUATIONS?
www.nasa.gov 5 Thrust Thrust National Aeronautics and Space Administration
Engine dynamic simulation development
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~ Need an engine simulation that is capable of predicting
the engine dynamics and controller reactions/limits
In 2006:
• No engine dynamic simulation available (government or
industry)
• Information on stall/surge margin over the flight and
operation was not available
• No realistic engine controller that was comparable to the
FADEC
www.nasa.gov 8 SMI Dryden Glenn P&W Glenn National Aeronautics and Space Administration
Commercial Modular Aero Propulsion
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System Simulation 40,000 (C-MAPSS40k)
• 40,000 Lb Thrust Class High Bypass Turbofan
Engine Simulation
• MATLAB/Simulink Environment
• Publicly available (restricted to US citizens)
• Representative
dynamic
performance P2
T2 P 50 T50 WS O
• Realistic controller
LPC
• Realistic surge
margin calculations
2011 GRC Software of the Year Award nomination, ExceptionallCB Award, and NASA Group Achievement Award www.nasa.gov 10 Thrust Thrust National Aeronautics and Space Administration
Engine Control System
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• Power Management
- Responsible for holding current power level
• Protection Logic
Responsible for ensuring safe operation Adjusts Fuel Flow to ensure limits are observed Core Fan Core Fan Power Ps3 Speed Speed Accel Oecel Fuel Management Control Schedule
--.L --.L --.L
Throttle EPR Feedback
TT
NfFeedback www.nasa.gov 12 National Aeronautics and Space Administration
There is Risk Associated With Enhanced
•
Control
• Control Mode: - Fast mode to decrease throttle to thrust response time (increased risk of surge) - Overthrust mode to increase maximum thrust level (increased risk of structural failure) • Requirements: - Ensure continuous engine operation (the engine must not surge) - Maintain engine conditions within minimum survivability limits (i.e., maintain temperatures and speeds to ensure successful landing while still providing required thrust) www.nasa.gov 13 National Aeronautics and Space Administration
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Modification to Controller
Overthrust Fast Response
• Relaxed fan speed limit • Modified controlled gains
• Relaxed core speed limit • Adjusted accel schedule
• Added temperature limit
www.nasa.gov 14 Ncdot (rpm/s) National Aeronautics and Space Administration
NASA GRC Piloted Control Evaluation Facility
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Projection Screens Cockpit Nonlinear Digital Command Analog Command Simulation of a Signals Signals Four-Engine Transport Aircraft Video Video PC Four opies of C-MAPSS40k With Graphics Enhanced Control www.nasa.gov 16 National Aeronautics and Space Administration
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Yaw Damper
Wash- ~ Rudder command r ......
out Airframe r-+ ~ Filter www.nasa.gov 17 National Aeronautics and Space Administration
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Engines Used for Yaw Damper
Pilot Pedal Command Pilot Throttle Command
-
Pilot Input
r
rcommand
+
,
' G>
ThrustL Left Engines
$
Wash- + r ......
8PLA Airframe r-+ ~ out ~ ~, + ThrustR Filter Right Engines
~
PLA R Yaw Damper - Saturation Compensation Logic to Maintain
-
Differential Thrust Over Total Thrust - Pilot Throttle Command www.nasa.gov 18 National Aeronautics and Space Administration
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RESULTS:
Evaluation of Enhanced Propulsion Control on
Takeoff Distance
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Takeoff Distance Evaluation
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Takeoffs: Altitude vs Distance 2' -..
Stand ard Co nt ro I Q.I '0 830 ~ Enhanced Co nt ro I « 8000 1000 2000 3000 4000 SOOO 6000 7000 aooo 9000 Distance (It) • As expected, the use of Overthrust shortened takeoff distance significantly when compared to cases using standard takeoff thrust level • The pilot also found Overthrust mode to be useful in flight www.nasa.gov 20 National Aeronautics and Space Administration
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RESULTS:
Evaluation of Enhanced Propulsion Control on
Aircraft Stability and Control
www.nasa.gov 21 National Aeronautics and Space Administration
Multi-engine aircraft with rudder stuck in
•
neutral position
Types of tests included ...
• Yaw rate feedback to throttles to compare the fast
responding engines' ability to damp Dutch roll
compared to using nominal engines
• Manual manipulation of the throttles to determine
reduction in pilot workload
• Landing in crosswind to demonstrate differential
thrust performing rudder function
www.nasa.gov 22 National Aeronautics and Space Administration
Evaluation of the Aircraft's Ability to Damp Dutch
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Roll
• For each trial, the pilot initiated the Dutch roll using
the following procedure.
- He trimmed the aircraft at the desired altitude and speed - moved the stick hard over to the right and banked to 40°, and turned right maintaining the roll angle - rolled out at a desired heading by moving the stick hard over to the left, releasing with wings near level, thus causing the Dutch roll.
www.nasa.gov 23 Yaw Rate, degrees/s National Aeronautics and Space Administration
Final Approach
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~ ~
(
~ <t
/
V
..E o :: . ~- Ground track of impaired aircraft flying The pilot's view toward the airport toward airport (CLE). (CLE) on approach.
www.nasa.gov 25 Yaw Rate, deg/s Roll Rate, deg/s d(PLA)/dt, %/s d(PLA)/dt, %/s National Aeronautics and Space Administration
Final Approach
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d g . , .: 920 _ Ground track of impaired aircraft flying The pilot's view toward the airport toward airport (CLE). Wind is shown (CLE) on approach.
decomposed in crosswind and headwind components.
www.nasa.gov 28 Thrust National Aeronautics and Space Administration
Final Approach
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The tests included approaches with 10 kt crosswind with rudder stuck in neutral position.
• Yaw rate feedback with and without enhanced control was used • Rudder pedals command throttle movement to generate differential thrust • Saturation compensation system maintained differential thrust rather than total thrust Things to Observe: • Pilot's rudder input for the baseline case is not near its limit • The crosswind could be accommodated by differential thrust • Pilot's unwillingness to be aggressive enough at the beginning of the approach required extra thrust to compensate later.
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180 180 180 www.nasa.gov ~ ~ ----__, ~-- 160 160 100 ~~~~ line) 140 1~ -n~~ (solid -.~~~~~ 120 120 1W
Landing
throttle
for
100 100 100 right s :L==r--------- lime, and
Crosswind
~ 80 80 ~~
Kt
line) 60 60 00
Commands
in
(dashed 40 40 ~
Throttle
throttle FOT 20 20 W Baseline Split Throttles YRF,Nom YRF, Left ----~~--~~----~------~----~------~------~----~ - - - - ~------------------------ ~ o 4,------,------,------,------,------,------,--- 2 80 80 60 40 Rudder Command, volts Total PLA, degrees Pilot PLA Input, degrees National Aeronautics and Space Administration National Aeronautics and Space Administration
Conclusions
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• C-MAPSS40k engine simulation has been developed and is available to the public • The authenticity of the engine performance and controller enabled the development of realistic enhanced control modes through controller modification alone • Use of enhanced control modes improved stability and control of an impaired aircraft - Fast Response is useful for manual manipulation of the throttles - Use of Fast Response improved stability as part of a yaw rate feedback system - Use of Overthrust shortened takeoff distance, but was generally useful in flight, too • Initial lack of pilot familiarity resulted in discomfort, especially with yaw rate feedback, but that was the only drawback, overall the pilot found the enhanced modes very helpful www.nasa.gov 32 National Aeronautics and Space Administration
Future Work
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• Loss of control prevention, mitigation, and recovery
- Working on integrated flight/propulsion control with partners at NASA Langley and Pratt & Whitney - Modifying C-MAPSS40k to model high angle of attack operation realistically www.nasa.gov 33
Acknowledg ments
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• OA Guo • Ryan May • Jeff Csank • Tom Lavelle • Shane Sowers • Amy Chicatelli • Chris Fulton • Karl Owen • James Liu National Aeronautics and Space Administration •• +
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+ www.nasa.gov