Research on Passive Assist of Hip Joint Based on Muscle Metabolism

The passive exoskeleton has attracted more and more attention from researchers because of its small weight and portability. However, research on the passive exoskeleton of the hip joint during walking is rarely reported. In order to expand the application of passive exoskeletons in walking assist, this article analyzed human biomechanical characteristics through OpenSim and conducted passive assist research of hip joints based on the characteristics of muscle metabolism. First, starting from the biomechanical properties of the human body, the muscles and their functions related to hip flexion/extension were identified. Further, through the study of muscle metabolism, the support phase was used as the assist phase, and a variable-stiffness hip passive assisted exoskeleton was added to the simplified human musculoskeletal model. Finally, through the OpenSim simulation, the total metabolism of the support phase at different stiffness and the metabolism of the muscles which drive the hip joint were compared. The effect of changes in the stiffness of passive exoskeleton on human metabolism was studied, and a stiffness which is capable of reducing metabolism by 12.84^% was obtained. On this basis, the stage of assist was optimized based on the muscle force with/without assist, and the metabolism was further reduced by 21.56%.