Design And Research Of Hydraulically Driven Lower Limb Exoskeleton Robot

The wearable lower extremity exoskeleton robot is a human-machine integrated system for assisting walking.It has the function of supplementing or completely replacing the functions of human limbs,and has been used in military,medical,industrial and other fields.At present,the heavy-duty lower limb exoskeletons in the industrial field generally have problems such as poor flexibility,heavy weight,and poor following performance,which seriously affects the working efficiency of workers wearing exoskeletons for labor operations.This article aims to enhance the human body’s weight-bearing capacity and uses the principles of bionics to design a heavy-duty lower extremity exoskeleton robot that is highly flexible,light and can meet the needs of most people,and using the methods of theoretical analysis,simulation verification and experimental analysis to study the structure design,kinematics and dynamics characteristics,drive system,mechanism strength and safety performance of the exoskeleton robot.The main research work is as follows:Based on the movement mechanism and structural characteristics of the lower limbs of the human body,the design principles of the three main joints of the lower limb exoskeleton robot are analyzed in detail.In response to the wearing needs of people of different heights and postures,a leg extension device is designed in the middle of the large and calf shafts,and a hip size adjustable device is designed at the waist fixing plate.The final designed lower extremity exoskeleton robot has a simple structure,is suitable for a wide range of people,and can cooperate with the wearer to complete routine movements such as walking,squatting,and standing.Based on the D-H parameter method,the positional relationship equations between the various structural members of the lower limb exoskeleton robot and the joint nodes are obtained.Based on the Lagrangian method,a dynamic model was established,and the dynamic equation of the driving torque at the main joints of the exoskeleton was obtained.The man-machine virtual prototype model was built using ADAMS software,the manmachine co-simulation analysis was completed,the rationality of the mechanism design and the man-machine followability were verified,and the driving torque curve of the main joints of the exoskeleton was obtained.A follow-up test was carried out on the human body and the exoskeleton,and the results show that the exoskeleton structure is reasonable in design and has good followability.The hydraulic drive is selected as the drive mode of the lower extremity exoskeleton robot.According to the working requirements of the exoskeleton robot drive system,the form of the hydraulic actuator and the main parameters of the hydraulic system is determined,and the hydraulic drive principle scheme is drawn up.According to the main parameters of the hydraulic system,the components of the hydraulic system are designed in detail.The hydraulic cylinder is designed independently,and important parameters such as its inner diameter and wall thickness are determined.Other components are analyzed in detail and selected a suitable mature product.Based on ANSYS Workbench software,a static analysis of the lower limb exoskeleton robot mechanism in a typical gait pose was carried out,the stress distribution diagram was obtained,and the safety performance of the mechanical structure was analyzed.The modal analysis of the lower extremity exoskeleton robot mechanism in the standing phase posture is carried out with or without prestress,and the natural frequency and vibration shape of the mechanism are obtained,which effectively avoids the occurrence of resonance.