Predefined Time Attitude Tracking Control for Rigid Spacecraft Using Fully Actuated System Approach

For rigid spacecraft systems subject to external disturbances, this paper proposes a predefined-time attitude tracking control method based on fully actuated system (FAS) theory. Firstly, a fully actuated spacecraft attitude tracking error system is established. Then a nonlinear extended state observer is designed to rapidly estimate disturbance external disturbances. By integrating FAS feedback with predefined-time sliding mode control, a novel control law is constructed using the estimation for feedforward compensation. Furthermore, rigorous stability analysis via Lyapunov theory verifies that all closed-loop signals converge to a small neighborhood within a predefined time. Finally, simulation results verify the effectiveness of the proposed method.