Vibration Suppression of a Maneuvering Flexible Spacecraft with Actuator Dynamic

This paper presents a study concerning active vibration control of a smart, flexible spacecraft during attitude maneuver using thrusters/ a reaction wheel and piezoelectric patches. The large-angle maneuver and residual vibration of the spacecraft are controlled utilizing an extended Lyapunov-based design (ELD) and strain rate feedback (SRF) theory. The single-axis fully coupled rigid-flexible dynamic of the system is derived applying a Lagrangian approach and Assumed Mode Method (AMM). The system's overall stability, including energetic terms covering a hub, two flexible appendages, PZT sensor/actuator, RW dynamics, and torsional spring, has been proved, and the control law has been derived accordingly. A pulse-width pulse-frequency (PWPF) modulation is used to alleviate the excitations of high-frequency flexible modes. However, due to the fast maneuver, there are still residual vibrations in the system. Hence, the SRF algorithm using PZT is applied to prepare further vibration suppression. The performance of the proposed extended controller is compared to the conventional Lyapunov and pole placement control algorithms. The numerical results for simultaneously large angle attitude and vibration control of a flexible spacecraft through a comparative study verify the merits of the proposed approach.