Passive robot based measuring method for intravehicular and extravehicular mobility unit spacesuit arm

A novel method to measure China's intravehicular mobility unit (IMU) and extravehicular mobility unit (EMU) spacesuit joints' mechanical characteristics is presented in this article. The measuring principle is based on robot kinematics, statics, and dynamics. Firstly, a kinematic model of the passive robot is built, and the universal kinematic models of the IMU and EMU spacesuit arms are also built according to the special mechanical structures. Secondly, the methods of solving the inverse kinematics of the IMU and EMU spacesuit arms including flexible joints are proposed. Finally, the damping torques of the spacesuit joints are calculated using the end torque, position, and orientation information of the spacesuit arms. The experimental results and simulation on SGI workstation prove the correctness and effectiveness of the presented measuring method.