MOMENTUM EXCHANGE - FEEDBACK-CONTROL OF FLEXIBLE SPACECRAFT MANEUVERS AND VIBRATION

The momentum exchange controller in which the time rate of change of the flexible momentum relative to the rigid-body motion is used as a part of the feedback control law for maneuvers and vibration suppression of flexible systems is introduced. This control concept is applied to a model of a rigid hub (base) with a cantilevered flexible appendage undergoing a single-axis maneuver. The feedback control on the hub includes the rigid-body motion and the time rate of change of that part of the flexible momentum resulting from flexible vibration. The lower and upper bounds of the control law for system Lyapunov stability am obtained, and the relationship of the control law with the energy Lyapunov test function is established. With the presence of this feedback control, an additional independent flexible control system acting on the flexible parts can be designed for further vibration suppression. This hybrid control system can be applied to both stationkeeping and large-angle maneuvers. Both analytical and numerical results are presented to show the theoretical and practical merit of this approach.