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Air-breathing hypersonic vehicle guidance and control studies: An integrated trajectory/control analysis methodology, phase 2An integrated trajectory/control analysis algorithm has been used to generate trajectories and desired control strategies for two different hypersonic air-breathing vehicle models and orbit targets. Both models used cubic spline curve fit tabulated winged-cone accelerator vehicle representations. Near-fuel-optimal, horizontal takeoff trajectories, imposing a dynamic pressure limit of 1000 psf, were developed. The first model analysis case involved a polar orbit and included the dynamic effects of using elevons to maintain longitudinal trim. Analysis results indicated problems with the adequacy of the propulsion model and highlighted dynamic pressure/altitude instabilities when using vehicle angle of attack as a control variable. Also, the magnitude of computed elevon deflections to maintain trim suggested a need for alternative pitch moment management strategies. The second analysis case was reformulated to use vehicle pitch attitude relative to the local vertical as the control variable. A new, more realistic, air-breathing propulsion model was incorporated. Pitch trim calculations were dropped and an equatorial orbit was specified. Changes in flight characteristics due to the new propulsion model have been identified. Flight regimes demanding rapid attitude changes have been noted. Also, some issues that would affect design of closed-loop controllers were ascertained.
Document ID
19930003225
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Hattis, Philip D.
(Draper (Charles Stark) Lab., Inc. Cambridge, MA, United States)
Malchow, Harvey L.
(Draper (Charles Stark) Lab., Inc. Cambridge, MA, United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1992
Subject Category
Aircraft Stability And Control
Report/Patent Number
NASA-CR-189703
NAS 1.26:189703
Accession Number
93N12413
Funding Number(s)
CONTRACT_GRANT: NAS1-18565
PROJECT: RTOP 505-70-64-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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