Kinematics Optimization of the Mechanical Structure of Human Forearm Ulna and Radius: Transformation From Pro- And Supination to Spatial Linkage Model and Motion Capture Validation

The aim of this study is to optimize the kinematic performance of the human forearm ulna and radius by converting the pronation and supination motion into a spatial four-link motion, which was verified with the Vicon motion capture system. Based on the research results of the Fick model, a new kinematic model is proposed, which models the forearm movement as the space connecting rod movement. The kinematic optimization realizes the mechanical adjustment of the rotation angle similar to that of the real human forearm, based on the length of the connecting rod, so as to more comprehensively explain the complexity of the proximal and distal end movement of the forearm during pronation and supination. Through simulation analysis, we verify the validity and feasibility of the model. The Vicon motion capture system is used to conduct experiments on subjects and collect motion data. The experimental results show that the optimized model is consistent with the actual motion, which verifies its accuracy and practicability. This study provides a new perspective and method for the understanding and application of human forearm kinematics.