Research On Reliability Analysis Method Of Lower Limb Exoskeleton Mechanism

With the development of science and technology and the advancement of medical level,the role of exoskeleton robots in human life is becoming more and more important.In the field of medical rehabilitation,exoskeleton robots can provide physical support and movement guidance for people with motor dysfunction,help them overcome movement obstacles,and perform actions that they cannot complete.In the military and industrial fields,it can significantly improve the wearer's load capacity,exercise capacity and exercise tolerance,can reduce human fatigue and avoid physical damage.In order to ensure that the exoskeleton robot can work normally and play its due role,when designing the exoskeleton robot,the relevant indicators should be reasonably formulated.The motion accuracy is a key indicator to measure the performance of exoskeleton robot.The concept of motion reliability can be used to characterize the changes in the accuracy of the movement of the end point of the exoskeleton robot under the influence of various errors.This article studies the motion reliability of lower extremity exoskeleton robots from two perspectives: kinematics and dynamics.The research object of kinematics method is static error,the error value is constant;the research object of dynamics method is dynamic error,the error value changes with time,and the influence of contact force,friction force and gravity on displacement reliability is considered in the process.The specific research work can be divided into the following parts:1.The kinematics modeling method D-H method has been improved accordingly,and the link coordinate system established in the non-real physical position in the D-H is transformed to the real physical position,which is convenient for the expression of the movement pair clearance error.Using the improved D-H method,the kinematic model of the lower extremity exoskeleton robot was established.2.The error source,error feature and error probability model are analyzed,and the error model of the lower limb skeletal robot is established,and the corresponding displacement reliability is calculated by the Monte Carlo method.3.In the dynamic simulation software ADAMS,the ideal model and error model of the lower extremity exoskeleton robot are established respectively,in which the error model is parameterized in size,and the joint clearance of the joint shaft hole is restored in the structure.By comparing the two types of models The simulation results calculated the corresponding displacement reliability.4.The displacement reliability data calculated above is summarized,the influence degree of each error on the displacement reliability of the terminal measurement point is summarized,and the reasons are analyzed.