Prescribed Performance and Predefined-Time Control of Spacecraft Rendezvous Based on Fully Actuated System Approach

Aiming at solving the problems of strong nonlinearity, external disturbances and obstacle constraints in the circular orbit dynamics of the target spacecraft, this paper proposes a comprehensive control strategy that integrates the fully actuated system approach, prescribed performance control, artificial potential field and sliding mode control. Firstly, the nonlinear relative dynamics model is transformed into a linear system with configurable characteristic structure by using the fully actuated system approach. Secondly, the prescribed performance control is introduced, which ensures that the tracking error evolves within the preset boundaries. Further, the active obstacle avoidance is achieved by combining the artificial potential field, and a disturbance observer is designed to compensate for external disturbances. Finally, a sliding mode control law based on a predefined time and combined with an artificial potential function was derived. The stability of the closed-loop control system was analyzed using the Lyapunov method, and the effectiveness of the proposed control scheme was verified through numerical simulations.