Integrated Adaptive Guidance & Control for the X-37 during TAEM & A/L
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Transcript of Integrated Adaptive Guidance & Control for the X-37 during TAEM & A/L
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Integrated Adaptive Guidance & Control for the X-37 during
TAEM & A/L
J. SchiermanBarron Associates, Inc., Charlottesville, Virginia
Paul Kubiatko The Boeing Company, Huntington Beach
Air Force Research Laboratory ProgramDavid Doman, PM
Presented at the Aerospace Control and Guidance Systems Committee (ACGSC) Meeting
Grand Island, NYOct. 15-17
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Presentation Outline
Motivation/program background
X-37 IAG&C program
Some details on the developed technologies
Sample experimental results
Conclusions
Boeing presentation…
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Motivation & Technology Challenges
NASA & Air Force seeking to increase safety & reliability of next generation launch systemsHouse software algorithms onboard to recover the system when physically possible to:
Control effector and other subsystem failuresLarger than expected errors/dispersions
Nominal flying qualities not always recovered w/ inner-loop control reconfiguration aloneGuidance adaptation may be necessary to account for “crippled” vehicleFor unmanned, un-powered vehicles in descent flight phases - energy management problem critical for safe landing
If vehicle characteristics have changed, energy management problem has changed
Energy managed with in-flight trajectory command reshaping
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Feedback ArchitectureFeedback architecture involves three main loops
Inner-loop control / Outer-loop guidance / Trajectory command generation
Maintain attitude stabilityRecover cmd. following performance to extent possible
Inner-loopCmds.
Meas.Resp.Reusable
Launch Vehicle
Reconfigurable Controller
EffectorCmds.
We have borrowed our reconfigurable flight controls
technologiesWe have borrowed our
parameter ID technologies & developed new algorithms
Re-solve energy management problem – critical for autonomous, unpowered vehicles in gliding flight
Traj. Cmds.Trajectory Command Generation
Our main focus!
Maintain flight path stabilityRecover cmd. following performance to extent possible
GuidanceAdaptationAlgorithm
Guidance Laws
New approaches developed
Required InformationVehicle Health
Monitoring,Filters,
Parameter ID,…
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Background - AFRL Program – ’01 to ‘04Air Force’s Integrated Adaptive Guidance & Control (IAG&C) flight test programDemonstration platform: Boeing’s X-40A
Why the X-40A? Boeing accomplished 7 successful drop tests - hoped to eventually repeat drop tests w/new reconfigurable G&C algorithms
Risk reduction flight tests w/TIFSEnsure software can run in real timeVerify simulation-based performance analysis
Nominal approach trajectory
Reconfigured trajectory
Nominaltouchdown aim point
TIFS = Total In-Flight Simulator
TIFS simulated
“X-40A”
dynamics
Flight test results presented at SAE ’04 (Colorado)
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AFRL Program ExtensionIAG&C program extended – ’04-’05
Next logical step: continue work with Boeing to develop / demonstrate IAG&C technologies for their X-37 RLV
Ruddervators
Speedbrake
Bodyflap
Flaperons
Engineering, Operations & Technology | Phantom Works
Copyright © 2008 The Boeing Company. All rights reserved.Distribution A, Cleared for Public Release, Distribution Unlimited. Case No. 88ABW-2008-0085 WPAFB, OH
Program Summary Chart
Description: • Demonstrate integrated adaptive guidance
and control system with on-line trajectory re-targeting and reconfigurable control to compensate for control effector failures using a real-time hardware in-the -loop simulation.
Value/Benefits: • Safety and Reliability:
System can compensate for unknown model errors.• Weight: Reduce redundancy requirements.Key Technologies: • Adaptive / reconfigurable Guidance and
Control algorithms.Partners/Major Subcontractors• Barron Associates, Inc.
ID Task Name
1
2 1.0 Program Management3 Pogram Management
4 2.0 Guidance and Control5 2.1 Simulation Development and Integration
6 2.2 IAG&C System Design and Consultation
7 Final IAG&C System (Entry I) Delivered from Barrons
8 Final IAG&C (Entry II) System Delivered from Barrons
9 2.3 IAG&C System V&V (Entry I)
10 2.4 IAG&C System V&V (Entry II)
11 3.0 Software12 3.1 FMC S/W Requirements
13 3.2 IAG&C Integration in FMC
14 4.0 Avionics Lab15 4.1 ASIL S/W Requirements
16 4.2 IAG&C (Entry I) Integration in ASIL
17 4.2.1 IAG&C (Entry II) Integration in ASIL
18 4.3 ASIL Test Entry I
19 4.4 ASIL Test Entry II
20 5.0 Documentation and Final Report
5/169/19
Nov Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov Jan Mar MayQtr 3, 2003 Qtr 1, 2004 Qtr 3, 2004 Qtr 1, 2005 Qtr 3, 2005 Qtr 1, 2006
More technically accurate than flight tests
Engineering, Operations & Technology | Phantom Works
Copyright © 2008 The Boeing Company. All rights reserved.Distribution A, Cleared for Public Release, Distribution Unlimited. Case No. 88ABW-2008-0085 WPAFB, OH
Program Objectives
• Develop and demonstrate Integrated Adaptive Guidance and Control (IAG&C) algorithms for reusable launch vehicles by simulation analysis.
IAG&C algorithms developed under Phase II SBIRs and AFRL 6.2 X-40A IAG&C program.
• Demonstrate that IAG&C architecture will automatically compensate for control effector failures and plan new feasible trajectories in real time when they exist.
Test on-line ID of ablation effects & failures
• Raise technology and integration readiness levels of IAG&C system by testing algorithms in a real-time relevant simulation environment.
Utilize existing Boeing X-37 Avionics Simulation Integration Lab
Engineering, Operations & Technology | Phantom Works
Copyright © 2008 The Boeing Company. All rights reserved.Distribution A, Cleared for Public Release, Distribution Unlimited. Case No. 88ABW-2008-0085 WPAFB, OH
X-37 Simulation Environments Utilized
Matlab/Simulink Environment IAG&C System Design Linear Analysis (phase & gain margins) Limited Worst-on-Worst analysis capability
Shuttle Descent-Approach Program (SDAP) Environment Simulation validation Performance Assessment “Worst-on-Worst” Analysis Monte Carlo Analysis
Avionics Systems Integration Lab (ASIL) Environment Real-Time Performance Assessment
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Expanded Envelope – TAEM and Approach & Landing
Focus: Boeing’s X-37 drop testsSubsonic portion of TAEMApproach & landing
Trajectory reshaping addresses integrated TAEM/A/L mission
Groundtrack
Heading Alignment Cone
(HAC)
Approach/Landing
Separation & Dive
Touchdown & Rollout
Alt = 40K ftRange = 18.8 NM
Alt = 22.5K ftRange = 9.5 NM
Alt = 10K ftRange = 4.5 NM
Acquisition w/HAC
Groundtrack
Nominal initial
heading = -135 deg.
Heading Alignment Cone
(HAC)
180o heading
-90o heading
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Trajectory Reshaping ApproachNeed fast optimization approach - deliver new trajectory solutions in flight
Redefine complete trajectory in terms of a small number of parameters to be optimizedOnce solution is obtained: map parameters back to full trajectory historyTrajectory parameters:
Initial heading angleAltitude to start HAC turnAltitude to start Final Flare guidance lawDynamic pressure at touchdownCL, CD: models trim CL,CD
under failure condition
Optimization problem posed:Minimize lateral maneuvering
Keeps solution from unrealistic sharp turns
Groundtrack
yrwy
xrwy
o
HHAC
Drop
HAC Turn
HFF TDq
} d
Defines shape of last stage of dynamic pressure profile
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Guidance & Control Laws
L _ ruddervator
R _ ruddervator
L _ flaperon
R _ flaperon
speedbrake
bodyflap
Z cmdNLongitudinal
Guidance
Lateral Guidance
cmd Coordinated Flight
Controller
Receding Horizon Optimal (RHO)
Controller- - - - -
Control Allocator
X-37 Vehicle
cmd
cmd
PR
Modified Sequential Least Squares (MSLS)
Parameter ID
refqf
K
cmdcmd+
-
q
V, D, , q, H, , V , D
CommandedTrajectory States toGuidanceLaw
qK f
3-DOF Plant Model
3-DOF Plant Model
+
-qf
H
f K
cmdcmdf
+-
V, , L, DH
o HAC, H
ff TDH , q
Reshaping AlgorithmReshaping Algorithm
Longitudinal Backstepping Loops
Lateral Backstepping Loops
Ref. Cmds.
CL CD, CL, CD
Trajectory Cmd Generation
Measurement Feedback…
Lift, Drag
Series of backstepping/dynamic inversion feedback loops: maps to commanded trajectory histories(V, , X, H, etc.) that drive guidance loops
d
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X-37 Drop Mission Case StudyWorst case low energy (high drag) failure - SB locked @ 65 deg. & BF locked @ 20 deg.
Ablation effects (add more drag); headwind/crosswind; navigation errors; turbulence
Altitude Profile
Ground Track
• Simulink and RTHIL results very close• Adaptive system commands a “HAC turn”
soon into the mission – “cuts the corner” to reduce downrange distance to runway – conserves energy
• Adaptive system commands much steeper descent – increases kinetic energy at touchdown – allows for greater control authority to execute final flare
Real-Time, HIL results
Real-Time, HIL results
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HAC Angle
Right Rudder
Left Rudder
Body Flap
Speed Brake Direction
Scale Factor
Sink Rate (fps)
Pitch Angle (deg)
Groundspeed (fps)
Downrange (ft)
Crossrange (ft)
28 135 -6 -6 - - 40K EAFB HW 10% - 3.248 8.112 341.929 2151.379 0.168
29 135 -6 -6 - - 40K EAFB TW 10% - 0.456 7.372 304.959 3198.168 5.252
30 135 -6 -6 - - 40K EAFB HWCW 10% - 1.187 7.514 302.618 3293.566 5.557
31 135 -6 -6 - - 40K EAFB TWCW 10% - 0.638 5.433 302.733 3407.623 6.004
32 90 - - 20 65 40K EAFB TWCW 10% - 4.247 12.846 297.295 2222.689 14.536
33 100 - - 20 65 40K EAFB TWCW 10% - 2.941 12.655 296.131 2337.721 -14.367
34 110 - - 20 65 40K EAFB TWCW 10% - 2.746 12.792 295.110 2306.181 -18.777
35 120 - - 20 65 40K EAFB TWCW 10% - 6.915 13.613 308.312 2145.319 -15.605
36 130 - - 20 65 40K EAFB TWCW 10% - 3.050 13.336 303.750 2283.586 -11.120
37 140 - - 20 65 40K EAFB TWCW 10% - 6.749 13.194 309.011 2179.693 -8.396
38 150 - - 20 65 40K EAFB TWCW 10% - 6.151 13.251 308.032 2199.266 -7.053
39 160 - - 20 65 40K EAFB TWCW 10% - 6.963 13.030 311.628 2160.595 -6.790
40 170 - - 20 65 40K EAFB TWCW 10% - 6.882 13.350 308.939 2159.474 -5.692
41 180 - - 20 65 40K EAFB TWCW 10% - 2.429 13.559 301.803 2292.339 -4.995
42 135 - - -20 0 40K EAFB HW 10% - 0.351 5.665 292.011 3612.635 2.030
43 135 - - -20 0 40K EAFB TW 10% - 0.498 8.111 313.568 2884.063 0.658
44 135 - - -20 0 40K EAFB HWCW 10% - 0.525 8.746 257.944 4589.362 3.733
45 135 - - -20 0 40K EAFB TWCW 10% - 1.213 7.903 320.847 2831.176 0.806
46 135 - - 0 0 40K EAFB HW 10% - 2.642 6.965 312.638 2508.943 3.995
47 135 - - 0 0 40K EAFB TW 10% - 3.313 6.561 312.938 2666.653 5.364
48 135 - - 0 0 40K EAFB HWCW 10% - 2.416 6.906 315.066 2516.830 3.881
49 135 - - 0 0 40K EAFB TWCW 10% - 4.497 6.550 317.696 2701.305 4.799
50 135 - - 0 30 40K EAFB HW 10% - 0.765 8.665 303.502 2247.709 1.036
51 135 - - 0 30 40K EAFB TW 10% - 1.247 8.239 309.674 2349.663 1.709
52 135 - - 0 30 40K EAFB HWCW 10% - 0.945 8.609 308.798 2168.552 0.998
53 135 - - 0 30 40K EAFB TWCW 10% - 1.894 8.150 311.511 2365.091 1.613
Touchdown ConditionsAblation Effects
Input File Name
FailureOnset
Alttitude
Wind
Real-Time HIL Experiment Results51 cases run for final set of real-time Hardware-In-the-Loop experiments
Variations included: initial heading (HAC) angle, wind direction, ablation effects, navigation errors, random turbulence, failure condition, and failure onset time
HAC
AngleRight
RudderLeft
RudderBody Flap
Speed Brake Direction
Scale Factor
Sink Rate (fps)
Pitch Angle (deg)
Groundspeed (fps)
Downrange (ft)
Crossrange (ft)
2 135 - - - - - - - - 0.862 4.888 307.616 3146.118 2.089
4 135 - - - - - EAFB HW 10% - 0.151 7.940 332.815 2107.260 -0.357
5 135 - - - - - EAFB TW 10% - 0.886 4.855 305.884 3138.804 2.282
6 135 - - - - - EAFB HWCW 10% - 0.263 7.342 310.121 2888.012 1.903
7 135 - - - - - EAFB TWCW 10% - 1.646 7.433 279.657 4255.383 11.890
8 90 - - - - - EAFB HW 10% - 0.946 4.948 301.318 3090.743 2.893
9 180 - - - - - EAFB TW 10% - 0.785 7.772 339.080 2223.361 -1.217
10 -90 - - - - - EAFB HWCW 10% - 2.741 7.516 362.810 1678.703 0.661
11 -135 - - - - - EAFB HWCW 10% - 1.795 6.308 312.033 2760.766 4.611
12 -180 - - - - - EAFB TWCW 10% - 1.025 4.123 308.488 3317.897 5.073
13 135 - - 20 65 40K EAFB HW 10% - 5.624 13.324 290.315 2223.785 -10.804
14 135 - - 20 65 40K EAFB TW 10% - 3.990 13.133 301.424 2258.649 -7.286
15 135 - - 20 65 40K EAFB HWCW 10% - 6.440 13.252 291.252 2207.018 -10.619
16 135 - - 20 65 40K EAFB TWCW 10% - 2.578 13.413 300.683 2311.176 -8.793
17 135 - - 20 65 35K - - - 4.462 13.203 282.470 2316.449 -9.808
18 135 - - 20 65 34K - - - 5.690 13.745 284.886 2286.887 -9.536
19 135 - - 20 65 33K - - - 3.049 13.081 291.950 2343.315 -10.895
20 135 - - 20 65 40K EAFB HW 10% on 2.719 14.398 272.435 2450.673 -25.214
21 135 - - 20 65 40K EAFB TW 10% on 6.571 14.713 296.541 2255.102 -23.289
22 135 - - 20 65 40K EAFB HWCW 10% on 2.943 14.296 271.692 2467.679 -25.329
23 135 - - 20 65 40K EAFB TWCW 10% on 3.394 14.846 292.592 2315.862 -23.868
24 135 - -6 - - 40K EAFB HW 10% - 1.448 8.150 312.263 2694.925 -15.266
25 135 - -6 - - 40K EAFB TW 10% - 2.730 7.804 316.690 2735.908 -16.530
26 135 - -6 - - 40K EAFB HWCW 10% - 1.846 8.053 313.906 2606.651 -16.504
27 135 - -6 - - 40K EAFB TWCW 10% - 2.871 7.710 319.479 2785.804 -14.749
Touchdown ConditionsAblation Effects
Input File Name
FailureOnset
Alttitude
Wind
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All 51 cases achieved required touchdown conditions
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ConclusionsBarron Associates focus:
Develop integrated TAEM/Approach & Landing trajectory reshaping and inner-loop reconfigurable controller
Non-real-time Matlab/Simulink experiments performed during development
Substantial number of experiments were run with dispersions in trajectory geometry, winds, failure characteristics, and other errors
Overwhelming majority of these runs resulted in safe landings
Without the advanced algorithms, failures would cause loss of vehicle
Trajectory reshaping coupled with reconfigurable inner-loop control saved vehicle from significant damage under severe effector impairments
Boeing tested algorithms in real-time simulations…