Adaptive output feedback sliding-mode manoeuvring and vibration control of flexible spacecraft with input saturation

A dual-stage control system design scheme for rotational manoeuvre and vibration stabilisation of a flexible spacecraft in the presence of uncertainty/external disturbances as well as control input saturation. More precisely, two separate control loops are designed. The first one uses piezoceramics as sensors and actuators to actively suppress certain flexible modes by designing modified positive position feedback compensators which add damping to flexible structures. The second is designed based on an adaptive output feedback sliding-mode control design where control input saturation is explicitly taken into consideration. The attitude controller has the ability to reject the disturbance, deal with uncertainty and to ensure that the system trajectories globally converge to the sliding mode. A modified version is designed for adapting the unknown upper bounds of the lumped perturbations as well. To study the effectiveness of the corresponding control scheme, the traditional adaptive static output feedback control case is also developed for the control system. Both analytical and numerical results are presented to show the theoretical and practical merits of this approach.