Anti-unwinding nonsingular terminal sliding mode control with attitude maneuver planning for flexible spacecraft

In this article, a novel control approach with a dynamic parameter and an attitude maneuver planning scheme is proposed for flexible spacecraft to achieve anti-unwinding attitude maneuver control and vibration suppression. In order to suppress the flexible modal vibration of the flexible spacecraft during the attitude maneuver, an attitude maneuver path is planned by the proposed attitude maneuver planning scheme with four input impulses satisfying some conditions. For tracking the planned reference attitude maneuver path without unwinding phenomenon, a robust attitude maneuver controller with a dynamic parameter is proposed based on a novel switching function which contains terminal and non-terminal sliding manifolds. Besides, the obtained sliding surface contains two equilibria. Finite-time convergence and unwinding-free performance of the closed-loop system are analyzed by Lyapunov theory. The simulation results demonstrate that the proposed attitude control scheme possesses robustness and anti-unwinding performance. Besides, the flexible vibration can be suppressed by tracking the planned attitude maneuver path.