Backstepping-based relative-attitude control for the leader-follower spacecrafts
基于反步法的主从航天器相对姿态控制

An attitude-control scheme based on the backstepping technique is developed for controlling the relative attitude between the leader spacecraft and the follower spacecraft, and the adaptive control law is applied to deal with the uncertainties in the follower spacecraft attitude system. According to the current relative positions between the leader and the follower, this scheme determines the required attitude of the follower to align its observation axis to the leader, and the required attitude of the follower to track the orbital coordinates of the leader. With the above-obtained results, an adaptive backstepping attitude controller is synthesized for the follower with unknown inertia matrix, based on the follower attitudeerror dynamic model represented by modified Rodrigues parameters (MRP). Lyapunov stability analysis shows that the developed controller ensures the relative-attitude control system for globally asymptotical stability. Simulation results of the application to a spacecraft formation flying show the effectiveness and feasibility of the designed controller.