Variable Stiffness Flexible Jointfor Lower Limb Rehabilitation Mechanism Design And Research

Lower limb rehabilitation institutions can help patients with lower limb injuries to complete the task of physical rehabilitation training effectively,which has important practical significance for improving the quality of life of patients and promoting family harmony.As an important part of the lower limb rehabilitation mechanism,the variable stiffness joint can improve the safety of the human lower limb during the rehabilitation process,and has the advantages of saving energy and outputting flexible torque.The lower limb rehabilitation institution is a rehabilitation institution installed on the wheelchair climbing platform in the research group project.This institution can perform lower limb rehabilitation training when a patient is in a wheelchair.The lower limb joint is jointly completed rehabilitation training by combining the seat posture adjustment mechanism on the wheelchair.The lower limb rehabilitation organization shall cooperate with the human body during the limb rehabilitation process,and adjust according to the different stages of the human lower limb joint rehabilitation training.At the same time,in order to avoid secondary injuries to the lower limb during the rehabilitation process,and improve the safety of the lower limb during the rehabilitation training,it also meets the requirements of changes in angle and torque when the joint rotates.Based on the port-based ontology design method,a new type variable stiffness joint is designed to improve the safety and reliability of the lower limb rehabilitation mechanism when training the limb.The subject is mainly studied from the following aspects;(1)Briefly describe the design method of port-based ontology,establish a musculoskeletal model of the human knee joint,analyze the stiffness characteristics and ontology properties of the knee joint,match the port functional properties of the human joint stiffness changes with the mechanical joints,and analyze function and the port properties of the mechanical variable stiffness joints attributes to obtain multiple joint solutions with variable stiffness;obtain human joint motion parameters by establishing a human coordinate system,combined with the motion requirements joints with lower limb rehabilitation institutions,and use Fuzzy Analytical Hierarchy Process(FAHP)to analyze multiple programs evaluation,so as to choose an optimal solution;(2)A new type of variable stiffness joint is proposed.The principle of joint variable stiffness is analyzed,and combined with the rehabilitation training requirements of lower limb rehabilitation institutions and the characteristics of Archimedes spiral,a joint variable torque output model is established to obtain output torque and stiffness of the joint change rule.Three-dimensional model of joint,analysis of joint variable torque adjustment method and design process of important mechanism parts,and check calculation of elastic components;(3)The established mathematical model is theoretically simulated,and the characteristics of joint output torque and stiffness change are analyzed.The finite element analysis software is used to verify the check calculation of leaf spring.Based on Adams software,the Three-dimensional model of the designed joint is used to build a simulation experiment platform,obtained the joint output torque characteristics through simulation experiments,and compared with the theoretical analysis,At the same time,position follow simulation experiments are performed on the joints to determine the stability of the joint movement under the load,and to verify the feasibility and rationality of the variable stiffness joint scheme.