Finite-time and collision avoidance control for spacecraft terminal approach with input saturation

This paper solves the avoid collision problem of spacecraft terminal approach to realize that a chaser spacecraft does not collide with the target spacecraft when reaching to the expected target point. The spacecraft relative motion and the collision avoidance model are established under the orbital coordinate system of target spacecraft. Two finite-time collision avoidance controllers are presented respectively in cases with/without knowing the upper bound of external disturbances, and the designed controllers have input saturation characteristics. Finally, Lyapunov stability theory is applied to prove the finite-time convergence of the designed controllers, and the collision avoidance potential function is used to prove that the controllers can realize the collision avoidance. Simulations demonstrate the effectiveness of the proposed controllers.