Active Vibration Control of a Maneuvering Flexible Spacecraft using Hybrid Actuators: A Lyapunov-Based Control Approach

This paper presents a study concerning active vibration control of a smart flexible spacecraft during attitude maneuver using thrusters and reaction wheels (RW) in combination and piezoelectric (PZT) sensor/actuator patches. The large-angle maneuver and residual vibration of the spacecraft are controlled using an extended Lyapunov-based design (ELD) and strain rate feedback (SRF) theory for a two-mode mission. The single-axis fully coupled nolinear rigid-flexible dynamic of the system is derived applying a Lagrangian approach and Finite Element Method (FEM). The overall stability of the system including energetic terms covering a hub and two flexible appendages, torsional spring, RW, and PZT dynamics, 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. A great feature of the proposed hybrid actuator system is the switching time of the thrusters and RW, which is based on total system energy. The numerical results for a flexible spacecraft with large-angle, agile, and precise maneuver requirements through a comparative study verify the merits of the proposed approach.