Switched Hybrid Control for Spacecraft Attitude Control With Flexible and Guaranteed Performance

This article addresses the challenge of achieving spacecraft attitude control with guaranteed performance while significantly reducing actuator activation frequency. To tackle this issue, we propose the concept of switched hybrid control and further integrate it with a modified prescribed-performance control (PPC) scheme. To enhance the robustness of the PPC control, we introduce the concept of a zeroing barrier function (ZBF). Coupled with a projection-operator-based modification dynamics, this approach assesses and adjusts the envelope in response to the risk of violating performance envelope constraints. Subsequently, a control mode switching strategy, considering the safety of the performance envelope and the system's motion velocity, is proposed. This strategy automatically switches between intermittent and continuous control modes to select an appropriate control command execution strategy, thereby reducing actuator activation frequency under proper circumstances. Furthermore, we demonstrate the boundedness of the closed-loop system for different control modes and establish a uniform upper bound of the Lyapunov certificate throughout the entire time domain, thereby proving the overall uniformly ultimately bounded (UUB) of the system. Finally, numerical simulation results are presented to validate the effectiveness of the proposed control scheme.