Adaptive Caging Configuration Design Algorithm of Hyper-Redundant Manipulator for Dysfunctional Satellite Pre-Capture

This paper presents an adaptive caging configuration design algorithm of the hyper-redundant manipulator for dysfunctional satellite pre-capture. Taking advantages of the extreme flexibility and hyper-redundancy, the hyper-redundant manipulator wraps its whole body around the dysfunctional satellite to restrain its motion without requiring grappling points and accurate information. However, the hyper-redundancy also makes the caging configuration design more complicated and challenging. In this paper, the dynamic sequential caging following algorithm based on rapidly-exploring random tree algorithm is proposed to search the caging configuration in real-time. First, according to the discretized caging trace, which is twining around the grasped object and selected based on the caging conditions, the joints of the hyper-redundant manipulator are divided into several groups in advance. Then, the joint angles are searched group by group to realize the match of the discretized caging trace by the hyper-redundant manipulator. As a result, the configuration between the grasped object and the hyper-redundant manipulator satisfies the caging conditions. The main advantages of the proposed caging motion planning algorithm lie in the avoidance of the inversion and the efficiency of computation. Finally, the pre-capture of two dysfunctional satellites with different shapes using a twenty universal joint manipulator is implemented, and the simulation results verify the efficiency of the proposed method.