Terminal Sliding Mode Control for Space Rendezvous and Docking

The relative motion control for spacecraft rendezvous and docking is considered. The relative position dynamics described in the target spacecraft's orbital frame, and attitude dynamics of the chaser spacecraft described in the chaser body frame are all formulated in Euler-Lagrange forms. Based on property analysis of the coupled dynamic model a terminal sliding mode control law is designed for the chaser with modeling uncertainties and external disturbances by using the Lyapunov redesign method. It is proved that the close-loop tracking error convergences to zero in finite time. Numerical simulation demonstrates effectiveness of the proposed control law.