Vibration suppression and composite prescribed performance detumbling control for a tumbling satellite

A servicing spacecraft installed with compliant flexible rod has recently emerged as an innovative solution for efficiently detumbling satellite. However, the undesired vibrations of the flexible rod are easily excited by the contact process, bringing detrimental effects for the accurate and safe operations. Besides, the contact-induced strong disturbance makes most of the existing controllers difficult to achieve guaranteed transient and steady-state performances. To conquer the above problems, a novel Nonlinear Energy Sink with Active Varying Stiffness (NES-AVS) device is proposed to significantly reduce the vibrations, wherein the AVS is realized by a small steel plate with the compression force adjusted by a piezoelectric actuator. Moreover, a composite prescribed performance detumbling controller is designed based on the fast non-singular terminal sliding mode control technique. A performance function is adopted to constrain the tracking errors to meet the prescribed dynamic properties, and an adaptive law is incorporated into the control framework to effectively reject the disturbance. Extensive simulations are conducted to demonstrate the effectiveness of the proposed NES-AVS device and controller.