Research On Design And Simulation Of Riding Walker Based On Virtual Prototype

With the progress and development of modern society,human society has gradually entered an ageing era.People age on their legs first,and walking has become a problem that middle-aged and elderly people must face in their daily lives.Because of this,the thesis designs a riding-type lower limb walker based on virtual prototype technology and conducts simulation research to establish a theoretical basis for the next step of the development and production of solid prototypes.It is designed to provide auxiliary power to the lower limbs of middle-aged and elderly people,reduce their burden of walking and standing,and at the same time have the function of helping middle-aged and elderly people to walk and exercise to improve their quality of life.In the thesis,on the basis of extensively reviewing the relevant research literatures on the design of exoskeleton assist devices,the design and simulation of the riding lower limb walker are completed based on the virtual prototype technology.First,based on the analysis and determination of the power-assisted mode,a structural model of the walker is constructed.According to the concept of ergonomics,the mechanism of human lower limb joint motion is analyzed.Referring to the structure and activity characteristics of the human body,the virtual prototype technology is used to design the walker prototype in SolidWorks that is based on the full analysis of the movement of the lower limb joints of the human body.Using SolidWorks to desicgn a virtual prototype of an exoskeleton assistance mechanism similar to the human body,it consists of a riding seat(equivalent to the hip),supporting thighs,supporting calves.ankle joints and shoe covers.When the exoskeleton power-assist device moves synchronously with the wearer,the two feet of the wearer are worn in the shoe cover,and the riding seat is always lifted upwards to provide the wearer walking assistance.Next,establish the kinematics and dynamics model of the assist mechanism,and study the factors influencing the effective assist.The kinematics simulation model is further established by establishing the kinematics model of the walking aid posture of the walker and using the mathematical relationship matrix to solve the model description method.The change law of each joint angle when the walking aid is walking smoothly is obtained through calculation.The virtual prototype technology is used to analyze the motion of the prototype in the ADAMS environment.Furthermore,the joint dynamics simulation model is constructed according to the Newton-Euler equation and Lagrange equation,and the advantages of the two are used to analyze the dynamic laws of walking aids and solve the joint driving torque.The simulation shows that the virtual prototype of the walker can walk stably and timely,which verifies the function and effectiveness of the design,and also lays the foundation for structural optimization,motor selection and drive controlFurther,based on the perception of walking posture and wearer intention,the power-assisted driving mode is analyzed and determined and the power-assisted control system is constructed.A knee swing angle adjustment structure with lithium battery as energy storage,joint motor as drive,synchronous belt and belt wheel as transmission chain is constructed,and the knee swing angle between the supporting thigh and the supporting calf hinged to the lower end of the supporting thigh is adjusted by synchronous belt and belt wheel.Install the lithium battery and joint motor on the upper end of the support thigh,and adjust the knee joint swing angle through the synchronous belt and pulley.Use the single chip microcomputer to collect the output data of the sensor,and design a closed loop control system based on the control of the joint motor driver to control the support force of the seat to the hip.Study the knee joint swing angle control method based on gait and intention perception,design the hardware system and compile the control programFinally,in the ADAMS environment,human-machine follow-up,gait simulation,and power-assisted effects of the virtual prototype of power-assisted walking are tested and evaluated.The analysis results of simulation experiments show that the walking aid model can meet the law of steady walking of the lower limbs of the human body in terms of step length,pace and step frequency,which proves that the walking aid can achieve the effect of smoothly assisting the human body walking:In the end.the evaluation of the assist effect of the walker is carried out.The evaluation result shows that the walker achieves the design requirements,which lays the foundation for the next physical prototype processing.