Anti-unwinding attitude maneuver control with predefined time for rigid spacecraft with input saturation

In this article, anti-unwinding sliding mode attitude maneuver control with predefined time is investigated for rigid spacecraft with input saturation. First, a nonsingular sliding function containing two equilibrium points is designed to ensure the predefined-time convergence of system states and unwinding-free performance of the closed-loop system on the sliding phase. Then, an auxiliary system with a dynamic parameter is presented to compensate the impact of input saturation. With this parameter, the auxiliary system can handle input saturation that occurs. Based on the sliding function and the auxiliary system, an attitude maneuver controller is developed to guarantee the robustness of the closed-loop system to bounded external disturbance. Under the designed controller, the states of the closed-loop system are driven into a neighborhood of the sliding surface within a predefined time. Moreover, the unwinding phenomenon is also avoided on the reaching phase. Numerical simulation results illustrate the unwinding-free performance and predefined-time convergence of the closed-loop system under the proposed control strategy.