Adaptive Reactionless Control of a Space Snake-Arm Robot for Pre/Post-capture of an Uncooperative Target

This paper focuses on the issues on the space snake-arm robot capturing an uncooperative target. Variations in the inertial parameters of the spacecraft reduce the performance of controller for snake-like robot. In order to minimize the disturbance of the robot motion on the base, an adaptive reactionless controller is designed by using the redundant characteristic of the robot. Firstly, the impact dynamics equation is given and the ideal velocities of the base and joints after capture are calculated as the measured values. Secondly the reactionless robot control method considering the avoidance of joint angle limits is proposed. Thirdly, the parameter identification method based on the momentum is proposed for estimating the unknown inertial properties of the end body of the snake-arm combined with unknown object. Finally, an example of 8 DOFs planar snake like manipulator is shown which validates that the reactionless motion is feasible while the inertia parameters can be identified accurately.