Robust output feedback control design for autonomous spacecraft rendezvous with actuator faults

This article documents a new output feedback guidance scheme for autonomous spacecraft rendezvous in the presence of actuator faults. The proposed approach is essentially a compound control methodology, which consists of higher order sliding mode observer and fast nonsingular terminal sliding mode technique. More specifically, the higher order sliding mode observer is used to estimate the relative velocity between two spacecraft while the fast nonsingular terminal sliding mode controller is used to regulate the relative position and the relative velocity to a small region around zero in finite time. The stability and performance of the closed-loop system are also analyzed using finite-time bounded function and Lyapunov function methods. Finally, numerical simulations are performed to demonstrate the robustness and effectiveness of the proposed method.