Attitude and Vibration Control in Nonlinear Flexible Spacecraft via Trajectory Shaping and Adaptive Sliding Control

A control scheme based on reference trajectory shaping and adaptive sliding control presented for the uncertain nonlinear underactuated system and is applied to the flexible spacecraft for its rotational maneuver control and active suppression of elastic vibration during the maneuver. The configuration of the proposed approach is that the input shaper is implemented on reference model to get the expected attitude angle, which achieves the exact reduction of residual vibration by modifying the existing command; while for the feedback loop, the feedback controller based on the adaptive sliding control, which settles the underactuated problem, is implemented to make the closed-loop system behave like the reference model with input shaper and suppress the residual vibrations. The proposed scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parametric uncertainties. Simulation results for the flexible spacecraft model show precise trajectory control and vibration suppression.