Design And Analysis Of Human Ankle Joint Assist Device

Ankle joint burdens the most weight of human body when people walk,run,and jump,which also needs to bear the largest impact from human body’s internal and external load,and the power that the ankle joint provides for people directly determines the stability of the human body when people do some exercises.Therefore,the research on rehabilitation assistance caused by human ankle injury is particularly important.The assisted exoskeleton is a kind of auxiliary equipment which aims at restoring human independence and improving human mobility.This equipment could compensate the body excessive physical exertion by using external device,especially for the old or those with ankle and foot diseases.Based on the Human Motion Biomechanics,Motion Capture System and foot Pressure Testing System,this thesis designed and analyzed the human ankle joint assist device,then some valuable conclusions are drawn after the experiment.The main content of the research is as followed:(1)Making a brief introduction about the research method on Ankle Joint Assist Device.Completed the Mechanical Model of Ankle joint by referring to the Kinematics Equation of Human Lower Extremity and D-H Seven-link Motion Model.(2)Putting up forward the Experimental Scheme of Human Gait data acquisition.The VICON optical motion capture system and AMTI foot Pressure Measuring Plate were used to collect the gait data,and Origin Software was used to process and analyze the results to obtain the angle,force and torque of the ankle joint in a single gait period.Then the accuracy of the Ankle Mechanics Model was verified,and the motion range of the assist device was determined.(3)Designing and analyzing the structure of the assist device.The movement of human lower limbs in the sagittal plane was analyzed,the degree of freedom and design criteria of ankle joint assist device were determined,and the mechanical structure design of the assist device was completed;drawing the schematic diagram of the mechanism,using the Solid Works’ s Sim Mechanics Link plug-in to analyze and find out the answers to the kinematics and dynamics of the mechanism,checking the strength and stiffness of the main components,and verifying the rationality of the mechanism movement,ensuring the safety of the device as well.(4)Man-machine coupling simulation was verified.Constructed the model of human lower limb and assist device by using Open Sim software and Matlab,which was compiled and run in Matlab.The kinematics and dynamics simulation of the combined model was realized in Open Sim.The coupled gait curve and the movement gait curve of human lower limb were contrasted and analyzed,then the research verified that the design of the device was not only in accordance with the design principles,but also has a positive effect.In this thesis,the author combined the theory with the experimental research,analyzing the law of force on human ankle joint movement,and verifying the designed power assist device could effectively reduce the force on ankle joint by18.7%.The results of this thesis has certain significance for ankle joint injury,power assist and device manufacture.