On attitude maneuver control of flexible spacecraft without angular velocity sensors

A novel attitude control strategy based on active disturbance rejection control (ADRC) and input shaping technique was proposed for a flexible spacecraft without angular velocity sensors. Aiming at achieving high rapidity and high pointing accuracy, we focus on the suppression of vibration of flexible appendages when the spacecraft´s attitude maneuvers a large angle. In the proposed scheme, a transient process which combines path planning for attitude maneuver with input shaping is designed to reduce vibration of flexible appendages. Furthermore, an extended state observer (ESO) for the flexible spacecraft is designed to estimate the immeasurable attitude angular velocity and the disturbances, which include parameter uncertainties and external disturbances. Also a nonlinear attitude feedback control law is designed to track the desired attitude and compensate the disturbances in real time way. Simulation results demonstrate the effectiveness and robustness of the proposed control strategy.