Collision Dynamics and Stable Control Strategy for Space Multi-arm Robot

Abstract

AbstractNon-cooperative targets capturing using a multi-arm (\({\ge}3\)) space robot is investigated. The system dynamics model of a four-arm space robot is first established in the terminal operating space. By analyzing the conservation of momentum of the entire space robot, the impact of dynamic coupling in the microgravity environment on the capturing tasks is avoided. This paper analyzes the relationship between the direction of the end contact force and the equivalent mass of the end of the multi-arm space robot during the collision. Then, based on the equivalent characteristics of the end, the system collision dynamics model of the space four-arm robot in the operating space is established. This model clearly describes the relationship among the contact collision force, the posture change of the end of the robot arm and the required control torque of each joint. Aiming at the sudden change of end pose caused by contact collision disturbance, an end pose deviation feedback controller is designed to ensure the stable operation of the capturing task. The controller adjusts the posture of the space robot according to the deviation value between the actual end position and the stable end position required by the task and the deviation value of the end speed. The results show that the controller can restore the manipulator to the required contact position in a short time, and the linear velocity reaches the expected state as well.KeywordsOn-orbit serviceMulti-arm space robotCollision dynamics modelEnd pose deviation feedback controller