Document
www.nasa.gov
N&R Engineering
, Consultant
, Vantage Partners, LLC
, NASA Glenn Research Center
28-30 July 2014
, NASA Glenn Research Center
A. Karl Owen
Yuan (James) Liu,
T. Shane Sowers
AIAA/ASME/SAE/ASEE Joint Propulsion Conference
Jonathan Litt
th
Ten-Huei (OA) Guo
Application and Evaluation of Control Modes
for Risk-Based Engine Performance Enhancements
National Aeronautics and Space Administration www.nasa.gov
Contents
Background Objectives Simulations & Results Summary & Conclusions
• • • •
National Aeronautics and Space Administration www.nasa.gov th th
Background
NASA Aviation Safety Program Emergency situations (e.g., runway incursion, airframe damage) may warrant unconventional usage of aircraft engines Overthrust (OT): Increase maximum thrust output Faster response (FR): More responsive transient thrust response Development of risk-based control modes that enhance engine performance for emergency use AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2011.
• • • • •
th Csank et al., “The Effect of Modified Control Limits on the Performance of a Generic Commercial Aircraft Engine,” 47 May et al., “Improving Engine Responsiveness during Approach through High Speed Idle Control,” 47 AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2011. Liu et al., “Design and Demonstration of Emergency Control Modes for Enhanced Engine Performance,” 49 AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2013 National Aeronautics and Space Administration 120 120 www.nasa.gov Baseline Overthrust Test Case Test Case 0 5 1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 10 15 20 25 30 Net Thrust Change, % Failure Probability
Control Mode: Overthrust
Control mode relaxes limits on temperature and rotational speeds Thrust available is increased Maximum overthrust at any operating condition is defined by a predetermined disk/blade failure risk level
• • •
AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2013.
th National Aeronautics and Space Administration Liu et al., “Design and Demonstration of Emergency Control Modes for Enhanced Engine Performance,” 49 180 180 160 160 www.nasa.gov Baseline Fast Response 80 Test Case 80 Test Case 0 2 4 6 8 -5 10 12 14 -25 -20 -15 -10 Minimum Stall Margin, % Rise Time Change, %
Control Mode: Faster Response
Control mode activation increases thrust responsiveness to throttle changes Modification to engine control system gains, schedules, etc. Risk of stall related to minimum stall margin attained during transient Reduction of minimum stall margin to consistent level AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2013.
• • • •
th National Aeronautics and Space Administration Liu et al., “Design and Demonstration of Emergency Control Modes for Enhanced Engine Performance,” 49 www.nasa.gov
Objectives
Propulsion: Commercial Modular Aero- Propulsion System Simulation 40k (C- MAPSS40k), NASA Glenn Airframe: Transport Class Model (TCM), NASA Langley Piloted flight simulator: Modular Flight Deck (MFD), Precision Flight Controls, Inc. Computer simulation (i.e., autopilot) Autopilot and piloted evaluations
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Apply control modes to aircraft simulation Evaluate effectiveness of control modes through simulations of emergency scenarios Runway incursions Flight control surface failure
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National Aeronautics and Space Administration www.nasa.gov
Aircraft clears 50 feet above ground level (AGL)
•
Incursion detected Throttles 90% to 100% Pull up to 15º pitch
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Runway Incursion
Aircraft stationary Throttles 0 to 90%
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National Aeronautics and Space Administration www.nasa.gov VP, kts Baseline, new Baseline, EOL Enhanced, new Enhanced, EOL 1300 1800 2300 2800 3300 XC - XP, ft
Runway Incursion
Baseline vs. enhanced performance New vs. end-of-life (EOL) engines Vary XP (point where incursion is detected)
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Test cases: Metric: additional distance required to clear 50 feet AGL (XC-XP) Greater improvement with earlier detection (but also less useful) OT mode with EOL engines nearly recovers baseline/new performance
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National Aeronautics and Space Administration www.nasa.gov L R
Thr Thr
-
+
+
+
FPA Roll
Controller Controller
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+ +
Flight Control Surface Failure
cmd sens cmd sens
γ γ φ φ
Failure of all primary flight control surfaces (elevator, aileron, rudder) Propulsion Controlled Aircraft (PCA): control system reconfigured to command engine power setting
• •
Burcham et al., “Development and Flight Evaluation of an Emergency Digital Flight Control System Using Only Engine Thrust on an F-15 Airplane,” NASA Technical Paper, 1996.
National Aeronautics and Space Administration www.nasa.gov 600 600 500 500 400 400 300 300 Time, s Scenario 2: Turn 200 200 Scenario 1: Climb/Descend 100 100 0 0 150 200 250 300 350 2000 4000 6000 Hdg Cmd, deg Alt Cmd, ft
Control Surface Failure: Evaluations
Evaluations of longitudinal and lateral aircraft maneuverability with baseline and enhanced engines Tests conducted by autopilot (“unaware” of control surface failure) and human pilot Engine power settings are indirectly controlled through PCA control system
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National Aeronautics and Space Administration 600 600 www.nasa.gov Throttle, % Thrust, % 500 500 400 400 Time, s 300 300 200 200 100 100 0 0 20 40 20 40 Baseline Enhanced 600 600 500 500 400 400
Control Surface Failure
300 300 Time, s
Longitudinal Maneuvers—Autopilot
200 200 Nominal PCA, Baseline PCA, Enhanced 100 100 Autopilot does not compensate for slow response of baseline engines (commands too aggressive) PCA control gains may not be optimal 150 200 250
– – 2000 4000 6000
Air Speed, kts Altitude profile of PCA with enhanced control modes nearly identical to that of nominal aircraft (fully functional flight controls) PCA with baseline engines results in instability Performance-enhancing control modes provide protection against instabilities Altitude, ft
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National Aeronautics and Space Administration www.nasa.gov 500 500 400 400 300 300 Time, s 200 200 PCA, Baseline (3 runs) PCA, Enhanced (2 runs) 100 100 0 0 150 200 250 300 2000 4000 6000 Air Speed, kts
Control Surface Failure
Altitude, ft
Longitudinal Maneuvers—Piloted
Exact trajectory not required Just hit the altitude waypoints (e.g., 5000 feet, 6000 feet, 3000 feet)
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Maneuver requirements relaxed for piloted evaluations Pilot was aware of control surface failure, but unaware of engine control mode status Aircraft control with baseline engines more difficult, though the pilot was able to prevent instabilities for 1 of 3 baseline PCA runs
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National Aeronautics and Space Administration www.nasa.gov 500 500 Throttle, % Thrust, % 400 400 300 300 Time, s Left Engine 200 200 100 100 0 0 20 40 20 40 Roll response not ideal, but faster engines prevent instabilities Autopilot too aggressive in trying to maintain altitude during rolling maneuvers Baseline Enhanced
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500 500 500 500 400 400 400 400
Control Surface Failure
300 300 300 300
Lateral Maneuvers—Autopilot
Time, s 200 200 200 200 Nominal PCA, Baseline PCA, Enhanced 100 100 100 100 -20 150 200 250 300 350 160 180 200 220 240 4600 4800 5000 5200 5400 Roll, deg Heading, deg Air Speed, kts Altitude, ft National Aeronautics and Space Administration 350 350 350 350 www.nasa.gov 300 300 300 300 250 250 250 250 200 200 200 200 Time, s 150 150 150 150 100 100 100 100 PCA, Baseline (3 runs) PCA, Enhanced (3 runs) 50 50 50 50 0 0 0 0 -20 150 200 250 300 350 150 200 250 300 Roll, deg 4600 4800 5000 5200 5400 Heading, deg Air Speed, kts Altitude, ft
Control Surface Failure
Lateral Maneuvers—Piloted
Pilot had to hit heading waypoints (no trajectory requirement) No instabilities for baseline or enhanced engines Pilot tried to maintain altitude, but not at expense of stability Autopilot had tighter altitude control, but only successful with faster thrust response
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National Aeronautics and Space Administration www.nasa.gov
Summary & Conclusions
Control modes: engine performance enhancements based on failure risk elevation Control mode implementation on aircraft/propulsion simulation and flight simulator test bed Evaluated control modes using example flight emergency scenarios (runway incursion & flight control surface failure) Extra thrust reduces takeoff distance Faster response protects against instabilities if aircraft must be maneuvered with engines only
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National Aeronautics and Space Administration www.nasa.gov
Backup Slides
National Aeronautics and Space Administration 13200 15000 14000 13000 -3 www.nasa.gov 13000
<10
12800 12000 12600 11000 Core Speed, RPM Core Speed, RPM 10000 -3 12400
<10
12200 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1400 1450 1500 1550 1600 1650 1700 1750 1800 Disk Failure Probability T50, R
)
-3
Overthrust: Implementation
Core speed limit for disk failure Speed-temperature boundary for blade failure
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Reduced-order risk function used for control design and implementation (NOT used when evaluating results) Disk failure risk as function of core speed Blade failure risk as function of core speed and single turbine temperature Allowable elevated risk (10 manifested as:
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National Aeronautics and Space Administration www.nasa.gov
Baseline Overthrust
Overthrust: Implementation
Core speed and turbine temperature regulators used to maintain engine operating point on risk boundary Overthrust activation: PLA mapping switches from idle- to-max to idle-to-overthrust
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National Aeronautics and Space Administration 12500 12300 Baseline Risk Elevated Risk Baseline Max. OT: Ps30 Active OT: Ps30 Inactive www.nasa.gov 140 Threshold Ps30 Limit Active Ps30 Limit Inactive 12100 Test Case 11900 Core Speed, RPM Operating Point 11700 11500 1900 1950 2000 2050 2100 2150 2200 T48, R 1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 Failure Probability Ps30 Limit Active Ps30 Limit Inactive
Overthrust: Results
Test Case Operating Point Tested at 180 operating points (0 to 4000 feet, Mach 0 to 0.3, standard to +40°R ambient temp, new to full deterioration) Maximum power setting: baseline vs. overthrust Nc-T48 reduced-order risk boundary (LPT inlet temperature) 0 5 10 15 20 25 30 Net Thrust Change, %
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National Aeronautics and Space Administration 5.5 - - - - 2.17% ±1.15% ±1.25% ±1.35% Random 4.5 www.nasa.gov - - - % 0.7% 6.0% 7.5% 0.36% 14.56% Non-random 3.5 2.5 Mean Stall Margin, 1.5 Inlet Distortion PLA Transient Inlet Distortion Reynolds Number Destabilizing Effects Fuel Control Tolerance Engine-to-Engine Variation Engine-to-Engine Variation 0.5 1.E-12 1.E-10 1.E-08 1.E-06 1.E-04 1.E-02 1.E+00 Stall Probability Total Surge Line Operating Line
corresponds to
-3 Stall Margin, %
Faster Response: Risk Function
-1
Stall
Stall margin reported by simulation equals mean Root-sum-square of random effects equals 3 standard deviations -2 – – Statistical stability assessment (SAE AIR1419 Rev. A, 1999) Risk of stall modeled as normal distribution Stall probability of 10 ~2.3% stall margin 0.1 0.2 0.3 0.4 0.5 0.6 Probability Density
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National Aeronautics and Space Administration www.nasa.gov
Fuel Flow
MAX RU min Ps30 min MIN Nf max Nc max Ps30 max Accel Sched Controller
Faster Response: Implementation
AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2011.
th EPR Setpoint AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2011.
Shifting acceleration schedule allows for faster dynamic response with lower minimum stall margin Iterative search conducted at 60 operating points (0 to 4000 feet, Mach 0 to 0.2, standard to +40°R ambient temperature, new to full deterioration) to determine offset values Implementation: 4-D interpolation on operating conditions to determine offset value th
PLA
Csank et al., “The Effect of Modified Control Limits on the Performance of a Generic Commercial Aircraft Engine,” 47 May et al., “Improving Engine Responsiveness during Approach through High Speed Idle Control,” 47
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National Aeronautics and Space Administration www.nasa.gov Baseline Fast Response Test Case Test Case Operating Point Operating Point 200 200 100 100 0 2 4 6 8 -5 10 12 14 -25 -20 -15 -10 Minimum Stall Margin, % Rise Time Change, %
Faster Response: Results
Tested at 540 operating points (within interpolation range) PLA from flight idle to maximum in 0.1 seconds Rise time: time to traverse 10% to 90% of difference between initial and final thrust levels
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National Aeronautics and Space Administration www.nasa.gov Models and control systems for aircraft and engines (TCM + C-MAPSS40k) Flight path predictor MPARS flight/propulsion control override algorithms
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Full cockpit with standard pilot/copilot controls and instrumentation PC 1: X-Plane PC 2: Displays PC 3: Everything else
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Spare Aircraft X-Plane Transport (TCM & C- MAPSS40K
Flight Simulator
Master_PC1 Visuals_PC2 National Aeronautics and Space Administration www.nasa.gov
Flight Simulator
National Aeronautics and Space Administration