Fault-tolerant Sliding Mode Controller and Active Vibration Control Design for Attitude Stabilization of a Flexible Spacecraft in the Presence of Bounded Disturbances

This paper concerns vibration control and attitude stabilization of a flexible spacecraft with faulty actuators. The PID-based sliding mode fault-tolerant scheme is developed to preserve the system against bounded external disturbances, rigid-flexible body interactions, and partial actuator failures. The proposed control law, which combines the advantages of the PID and SMC, is proposed to enhance the robustness and reduce the steady state errors while reducing complexity and the computational burden and preserving the great properties of the SMC controller. It has been shown that the SMC controller is effective in accommodating different actuator fault scenarios and behaves healthily. Additionally, an active vibration control (AVC) law utilizing a strain rate feedback (SRF) algorithm and piezoelectric (PZT) sensors/actuators is activated during the maneuver to compensate for residual vibrations resulting from attitude dynamics and actuator failures. Numerical simulations demonstrate the proposed schemes' superiority in fault tolerance and robustness compared to conventional approaches.