Robust adaptive control for spacecraft final proximity maneuvers with safety constraint and input quantization

In this paper, we tackled the robust quantized proximity control problem for spacecraft with uncertain system parameters, external disturbances and safety constraint. As a stepping stone, a nonconvex forbidden zone composed of a cylinder and an ellipsoid is established around the target spacecraft. Then, a novel repulsive potential function is employed to encode the collision-avoidance requirement. Furthermore, an adaptive safety controller is proposed for spacecraft rendezvous and docking by combining the artificial potential function with sliding mode methodology. Within the Lyapunov framework, rigorous stability analysis indicates that the presented controller guarantees the ultimate boundedness of all system signals, whilst providing a real-time safety trajectory for the chaser spacecraft. Finally, simulation results validates the theoretical analysis.