Finite-time sliding mode control for spacecraft rendezvous with collision avoidance

To deal with the problem of obstacle avoidance during the process of spacecraft safe rendezvous, a control methodology based on finite-time sliding mode control and artificial potential function is presented. Firstly, a correction for repulsive potential function is conducted so that the value of the potential function is zero at the desired state. Then, combining velocity error and gravity gradient to design a sliding surface. In order to design the control law, the velocity of the obstacles is taken into consideration. Using the Lyapunov stability theory to analyze and prove that the system can converge to the desired state in finite time and keep asymptotic stability in the presence of disturbances. Finally, numerical simulation is used to verify the validity and effectiveness of the proposed control law. According to the numerical results, this method can guarantee avoiding dynamical obstacles whilst satisfying the requirements of the safe rendezvous. © 2016, Editorial Dept. of JA. All right reserved.