Linear quadratic stationkeeping on travelling ellipsesAn automatic controller for Space Shuttle stationkeeping or formationkeeping is presented. The controller, which is a candidate for future on-orbit autopilot enhancement, uses a fuel 'optimized' limit cycle trajectory in a feedforward loop for precise control at nonequilibrium set points. Disturbance rejection is accomplished by a discrete time, linear quadratic regulator, which is employed for tracking of the feedforward model. Feedback gain selection is done to provide good limit cycling performance and low fuel consumption. Velocity correlations are carried out by use of a pseudo 6 degree-of-freedom jet selection scheme. Results indicate that 20 ft precision can be achieved using current sensors.
Document ID
19880029752
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Adams, Neil J. (Draper (Charles Stark) Lab., Inc. Cambridge, MA, United States)
Redding, David C. (Charles Stark Draper Laboratory, Inc. Cambridge, MA, United States)
Cox, Kenneth J. (NASA Johnson Space Center Houston, TX, United States)