Combined spacecraft stabilization control after multiple impacts during the capture of a tumbling target by a space robot

Target capture is a fundamental and essential task of space robots for on-orbit servicing in the future. Accordingly, it is important to study the method for space robot stabilization after impact during target capture. In this paper, the stabilization control problem of a combined spacecraft after multiple impacts during target capture is studied. A dual-integral sliding mode (DISM) control method based on the reconfiguration of the reaction wheels is proposed. The stability control of the combined spacecraft is achieved by controlling the reaction wheels of the space robot to absorb the angular momentum arising from the impact. First, given the structure of the gripper, the contact detection algorithm and contact dynamics model are established, and then multiple impacts are simulated during the target capturing operation. Second, an improved sliding mode control method is proposed to overcome the influence of multiple impacts, and the stability of the controller is confirmed by the Lyapunov method. Third, through an optimization method, the configuration of the reaction wheels of the space robot is reconstructed to avoid control torque saturation. The validity and availability are eventually verified by simulations and experiments. The results show that the proposed method can achieve the stability of the combined spacecraft after the target capture, and the algorithm is robust and has engineering applicability.