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Space Launch System Ascent Flight Control DesignA robust and flexible autopilot architecture for NASA's Space Launch System (SLS) family of launch vehicles is presented. The SLS configurations represent a potentially significant increase in complexity and performance capability when compared with other manned launch vehicles. It was recognized early in the program that a new, generalized autopilot design should be formulated to fulfill the needs of this new space launch architecture. The present design concept is intended to leverage existing NASA and industry launch vehicle design experience and maintain the extensibility and modularity necessary to accommodate multiple vehicle configurations while relying on proven and flight-tested control design principles for large boost vehicles. The SLS flight control architecture combines a digital three-axis autopilot with traditional bending filters to support robust active or passive stabilization of the vehicle's bending and sloshing dynamics using optimally blended measurements from multiple rate gyros on the vehicle structure. The algorithm also relies on a pseudo-optimal control allocation scheme to maximize the performance capability of multiple vectored engines while accommodating throttling and engine failure contingencies in real time with negligible impact to stability characteristics. The architecture supports active in-flight disturbance compensation through the use of nonlinear observers driven by acceleration measurements. Envelope expansion and robustness enhancement is obtained through the use of a multiplicative forward gain modulation law based upon a simple model reference adaptive control scheme.
Document ID
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Orr, Jeb S.
(Jacobs Technologies Engineering Science Contract Group Huntsville, AL, United States)
Wall, John H.
(Jacobs Technologies Engineering Science Contract Group Huntsville, AL, United States)
VanZwieten, Tannen S.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Hall, Charles E.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
July 7, 2014
Publication Date
January 31, 2014
Subject Category
Launch Vehicles And Launch Operations
Report/Patent Number
AAS 14-038
Meeting Information
Meeting: 2014 American Astronautical Society (AAS) Guidance, Navigation, and Control Conference
Location: Breckenridge, CO
Country: United States
Start Date: January 31, 2014
End Date: February 5, 2014
Sponsors: American Astronautical Society
Funding Number(s)
Distribution Limits
Public Use Permitted.
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