Trajectory Tracking and Vibration Suppression of Spacecraft Combination Connected by a Space Manipulator

The on-orbit service system for fault repairing and function maintenance is one of the most important space projects that are being developed in China. After capturing a target spacecraft, the servicing and the target spacecraft constitute a combination under the connection of the space manipulator. This paper focuses on the trajectory tracking and vibration suppression of the spacecraft combination connected by a space manipulator. First, taking comprehensive consideration of all the flexible components as the joints, links and solar arrays, the dynamic model of the spacecraft combination is established and decomposed into two subsystems by use of the singular perturbation method. Then, a global terminal sliding mode (GTSM) controller of the slow subsystem is designed to track the trajectory of the space manipulator, and a linear quadratic regulator (LQR) controller of the fast subsystem is designed to suppress the vibration of the flexible components. Furthermore, a composite controller of the spacecraft combination is established by superimposing the two subsystem controllers. Finally, numerical simulations are carried out and the results illustrate that the composite control method is effective for both the precise trajectory tracking and potent vibration suppression of the spacecraft combination.