Sliding mode control of spacecraft system based on event-triggered stubborn composite disturbance estimator

To address the issue of multi-source disturbances in spacecraft relative motion, this study proposes a sliding mode control method based on an event-triggered stubborn composite disturbance observer. The stubborn composite disturbance observer is designed to handle electromagnetic disturbance, slowly time-varying disturbances, and harmonic disturbances acting on the spacecraft system. The event-triggered mechanism is employed to reduce communication frequency and mitigate the influence of outliers. The sliding mode controller (SMC) ensures rapid convergence of the relative motion system to the equilibrium point. Sufficient conditions for the convergence of the proposed composite disturbance observer are provided. In addition, the stability of the closed-loop system under the sliding mode controller is guaranteed. Finally, numerical simulations verify the effectiveness of the proposed method.