| In recent years,as the problem of population aging in China continues to worsen,there is an urgent need for a series of methods to solve or alleviate this phenomenon,among which lower limb exoskeleton robots are a very effective response measure.Currently,both domestic and foreign countries have begun to increase investment in related fields.The lower limb exoskeleton is an electromechanical device worn on the surface of the lower limb of the human body.Its purpose is to improve the wearer’s athletic performance,integrating mechanical,control,sensing,and other technologies.Traditional lower limb exoskeletons have certain problems in integrating with human motion,there are certain motion biases in the process of human-machine cooperative motion,and for elderly people,some of the body’s structures will change to varying degrees as they age,which will pose a challenge to traditional design methods.This article is mainly based on the regular data collected and calculated from biomechanical experiments and human anatomy theories,and focuses on these theories to carry out mechanical structure design,kinematics and dynamics analysis and simulation,as well as physical prototype exploration of the exoskeleton.The specific research content is as follows:(1)A three-dimensional spatial motion capture and analysis computing platform is built through the VICON MX system,and infrared high-speed cameras are used to capture the gait movements of subjects in this three-dimensional space in real time.At the same time,each frame of collected data is imported into the system database.The system software performs corresponding mathematical processing on these original data to obtain valuable data,and theoretical analysis is conducted on these data,At the same time,human anatomy theory is used to explore the structure and movement status of the main joints of the human lower limbs,providing theoretical support for subsequent structural design.(2)Based on the collected biomechanical data,the mechanical structure design of the lower limb exoskeleton was carried out.Firstly,the size of each segment is designed based on the proportion of the human body,the main materials are selected based on lightweight and strength performance,and the motor model is determined.The active and passive degrees of freedom of the hip,knee,and ankle joints are allocated and designed in accordance with the principles of bionics and safety,as well as the laws obtained through analysis,as well as human-computer interaction design.Finally,the finite element analysis software ANSYS Workbench is used to conduct static analysis on the model to verify the safety of the model.On the premise of meeting safety requirements,topology optimization is conducted for key components to achieve the goal of lightweight.(3)The forward kinematics analysis of the model is performed using the D-H method,and the inverse kinematics analysis is performed using the geometric method.Using ADAMS simulation software and gait data collected from biomechanics,the forward kinematics simulation of the external skeleton simulation model was conducted.To explore the degree of joint matching between the exoskeleton structure and human motion.(4)Explore human-machine joint dynamics,and verify the synergistic effect of the exoskeleton and human-machine,as well as the assist effect of the knee joint,based on a physical prototype.Firstly,using the Lagrange equation method,two human mobility dynamics models are established for the support phase and the swing phase in gait.Using ADAMS simulation software and gait data collected from biomechanical experiments,the human machine "two state" dynamic model was simulated and validated.Secondly,a physical prototype was built to collect the motion angle of the hip joint through sensors and observe the torque changes of the knee joint during the process of squatting to standing up using the Vicon motion capture system,verifying the human-machine matching degree and passive assistance effect of the model. |
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