Research On Dynamic Performance Of Passive Energy Storage Human Lower Limb Exoskeleton Mechanism

The exoskeleton assist mechanism is a wearable device that reduces the metabolic energy consumption of the human body through human-machine collaboration to achieve assistance,while supporting and protecting the human body.In this paper,a passive energy storage human lower limb exoskeleton mechanism is designed for outdoor athletes and the elderly.The mechanism can store the gravitational potential energy and kinetic energy during human walking,and release them at the right time to help the human body walk,reduce the consumption of metabolic energy,and increase the walking distance of the wearer.In order to verify the assist effect of the proposed exoskeleton mechanism,this paper mainly studies the exoskeleton mechanism from the aspects of structure selection design,dynamic analysis and simulation verification.Firstly,the design parameters of exoskeleton mechanism are obtained by analyzing the human body size and lower limb movement of Chinese adults.According to the assist principle and design parameters,the scheme selection and structural design of the exoskeleton mechanism are carried out.The assist exoskeleton mechanism including hip,knee and ankle joints is designed,and its three-dimensional solid modeling and three-joint elastic element selection are completed.Secondly,the seven-link kinematics model of the exoskeleton mechanism is established.The position relationship of the lower limb end posture relative to the fixed coordinate system is obtained by using the D-H method,and the wearability of the exoskeleton mechanism is verified.Based on the Lagrange method,a seven-link dynamic model of human wearable exoskeleton mechanism with one foot support,two feet support and one foot virtual touchdown is established.According to the inertial parameters of the adult human body,the parameters in the dynamic model are determined.Based on MATLAB,the parameters are substituted into the dynamic model to obtain the lower limb joint torque curve in a gait cycle.Based on Adams,the simulation model of human body wearing exoskeleton mechanism is established,and the walking simulation analysis is carried out.The simulation results show that the mechanism can reduce the joint torque of human walking,and verify the assist effect of exoskeleton mechanism and the accuracy of theoretical model.Finally,the musculoskeletal model of human wearing exoskeleton mechanism is established by OpenSim software,and the walking simulation of the model is carried out by using the muscle calculation control module of the software.The changes of muscle strength,muscle activation and muscle metabolic energy before and after wearing were analyzed.The simulation results show that the exoskeleton mechanism can effectively reduce the muscle force,muscle activation and metabolic energy consumption during walking,and verify the assist effect of the mechanism from a biological perspective.This study provides a device for outdoor athletes and the elderly to walk long distances,and provides a valuable reference for the development of human walking aids.