Simulation of astronaut´s movement for orbital replaceable units

This study primarily focuses on the simulation of an astronaut moving the orbital replaceable units (ORUs) into the worksites in spacecraft payloads or removing them from these worksites. The upper limb model is established, which includes three segments of upper arm, forearm, and hand, as well as three revolute joints of shoulder, elbow, and wrist. Joint kinematical parameters during one period were obtained by using the numerical solution of reverse kinematical equation. The corresponding virtual upper limb model was established and simulated using LifeMOD software. Thus, the simulation results can be validated by comparing the simulation trajectories of the mass center of hands with that of hands´ known motion. Additionally, the joints´ strengths can be compared when hands move in different directions of the human body coordinate system. The results are useful to astronaut´s orbital mission planning and training in the ground.