Relative Position and Attitude Control for Drag-Free Satellite with Prescribed Performance and Actuator Saturation
An adaptive prescribed performance control scheme is proposed for the drag free satellite in the presence of actuator saturation and external disturbances. The relative translation and rotation dynamics between the test mass and outer satellite are firstly derived. To guarantee prescribed performance bounds on the transient and steady control errors of relative states,a performance constrained control law is formulated with an error transformed function. In addition,the requirements to know the system parameters and the upper bound of the external disturbance in advance have been eliminated by adaptive updating technique. A command filter is concurrently used to overcome the problem of explosion of complexity inherent in the backstepping control design. Subsequently,a novel auxiliary system is constructed to compensate the adverse effects of the actuator saturation constrains. It is proved that all signals in the closed-loop system are ultimately bounded and prescribed performance of relative position and attitude control errors are guaranteed. Finally,numerical simulation results are given to demonstrate the effectiveness of the proposed approach.