Simulation and experimental analysis of lower limb exoskeleton rehabilitation robot

QU Haijun; LI Tianliang; LIU Jianhui; QIN Xiaojun; YANG Yongqiang; LI Qiang; WANG Jinwu; NI Guohua; ZHAO Dongliang; WANG Jianping

doi:10.16186/j.cnki.1673-9787.2022070036

Abstract：Objectives In order to help the patients with lower limb movement disorders to get orderly reha-bilitation training,a lower limb exoskeleton rehabilitation robot was designed.The lower limb crossed swing driven by the power source can simulate normal human gait to achieve coordinated movement of both lower limbs and helped people with lower limb movement disorders complete rehabilitation training.Methods In this paper,the three-dimensional model of the exoskeleton robot was first drawn,and the D-H model of the lower limb exoskeleton robot was established.Then,the forward and inverse kinematics of the lower limb exoskeleton robot were analyzed,and the model was imported into ADAMS to create motion pairs and drive functions for kinematic simulation.On this basis,prototype was made and dynamic test and analysis was carried out.Results The forward and inverse kinematics verified the rationality of the exoskeleton robot´s motion in space.Through ADMAS motion simulation,the motion simulation results were obtained and the theoretical calculation was compared to prove that the motion was consistent.The simulation results were consistent with the theoretical calculation,and the designed exoskeleton lower limb structure was synchro-nized with the wearer's lower limb.The simulation analysis demonstrated that the error of theoretical calcu-lation and simulation mainly came from the error of driving function,the maximum error was 2.15 cm.The prototype was made according to the simulation,the dynamic test and experimental analysis verified that the motion of hip and knee joints was consistent with the ideal motion.But there were also errors in motion,the average error of hip joint was 5.57°,and the average error of knee joint was 5.45°.The source of error was from,firstly,the insufficient torque of motor,secondly,the parts machining accuracy and assembly accu-racy.Conclusions The feasibility of the scheme was verified by theoretical calculation,simulation and test analysis,and the errors were caused by driving errors,parts machining accuracy and assembly accuracy.The research results can provid the basis and parameter basis for further improving the performance of the robot and studying the dynamic factors of the rehabilitation robot dynamics.