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Airborne Simulation of Launch Vehicle DynamicsIn this paper we present a technique for approximating the short-period dynamics of an exploration-class launch vehicle during flight test with a high-performance surrogate aircraft in relatively benign endoatmospheric flight conditions. The surrogate vehicle relies upon a nonlinear dynamic inversion scheme with proportional-integral feedback to drive a subset of the aircraft states into coincidence with the states of a time-varying reference model that simulates the unstable rigid body dynamics, servodynamics, and parasitic elastic and sloshing dynamics of the launch vehicle. The surrogate aircraft flies a constant pitch rate trajectory to approximate the boost phase gravity turn ascent, and the aircraft's closed-loop bandwidth is sufficient to simulate the launch vehicle's fundamental lateral bending and sloshing modes by exciting the rigid body dynamics of the aircraft. A novel control allocation scheme is employed to utilize the aircraft's relatively fast control effectors in inducing various failure modes for the purposes of evaluating control system performance. Sufficient dynamic similarity is achieved such that the control system under evaluation is configured for the full-scale vehicle with no changes to its parameters, and pilot-control system interaction studies can be performed to characterize the effects of guidance takeover during boost. High-fidelity simulation and flight-test results are presented that demonstrate the efficacy of the design in simulating the Space Launch System (SLS) launch vehicle dynamics using the National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center Fullscale Advanced Systems Testbed (FAST), a modified F/A-18 airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois), over a range of scenarios designed to stress the SLS's Adaptive Augmenting Control (AAC) algorithm.
Document ID
20150023570
Acquisition Source
Armstrong Flight Research Center
Document Type
Conference Paper
Authors
Miller, Christopher J.
(NASA Dryden Flight Research Center Edwards, CA United States)
Orr, Jeb S.
(Jacobs Engineering and Science Services and Skills Augmentation Group (ESSSA) Huntsville, AL, United States)
Hanson, Curtis E.
(NASA Dryden Flight Research Center Edwards, CA United States)
Gilligan, Eric T.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
December 31, 2015
Publication Date
January 30, 2015
Subject Category
Spacecraft Design, Testing And Performance
Aircraft Stability And Control
Report/Patent Number
AAS 15-097
DFRC-E-DAA-TN20628
Meeting Information
Meeting: Annual AAS Guidance and Control Conference
Location: Breckenridge, CO
Country: United States
Start Date: January 30, 2015
End Date: February 4, 2015
Sponsors: American Astronautical Society
Funding Number(s)
CONTRACT_GRANT: NNM12AA41C
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
airborne simulation
adaptive control
launch vehicles
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