Design And Optimization Of Wearable Lower Extremity Unpowered Exoskeleton

For people who need to stand or squat for a long time and are vulnerable to occupational-related musculoskeletal disorders(WMSDs)and varicose vein diseases,such as assembly line workers,teachers,nurses and other occupational groups,this paper designs a wearable unpowered lower limb.The exoskeleton has both an auxiliary walking function and a gravity support function.The design requirements and testing methods of the exoskeleton are obtained by understanding the research status at home and abroad.Based on the anatomical knowledge,the motion of the joints of the lower limbs of the human body is described,and the gait is divided according to the periodic changes of the human body during normal walking.Angular changes in the sagittal plane.In this paper,several design schemes are proposed for the hip joint assist device and the gravity support device,and the optimal scheme is selected after comprehensively comparing factors such as product structure,energy storage element,locking method,manufacturability,and reliability.The parts are subjected to static analysis to verify their reliability,and finally the two devices are integrated to obtain an overall scheme.Simplify the human walking model into a five-bar linkage mechanism,establish a kinematic model of the lower limbs of the human body in the sagittal plane,and solve the step height data at the end of the exoskeleton after substituting the parameters,and analyze the ankle joint height obtained from the human walking video with Open Pose For comparison,the matching of the exoskeleton and the human body is verified.A simplified seven-link dynamic model of the human body is established,the dynamic model of each walking gait is established by using the EulerLagrange equation,and the curve of the hip joint torque of the lower limb exoskeleton of the human body with time is solved,and the use of Opensim to analyze the walking The hip joint torque obtained from the gait was compared to preliminarily verify the assisting function of the exoskeleton,and the human-machine coupling model was imported into Adams for dynamic analysis.The theoretical assisting effect of the exoskeleton was verified by comparing the torque data of the human body before and after wearing the exoskeleton.On the basis of completing the three-dimensional model,a physical prototype was made,and the ability of the exoskeleton to assist walking and support the body weight was verified through two types of experiments.Through the comparison of physiological parameters such as heart rate and blood oxygen before and after walking,the effectiveness of the power-assisted walking unit is proved;the experimenter maintains different sitting postures in three sitting postures: wearing an exoskeleton,relying only on their own strength,and sitting normally in a seat The comparison of the EMG signal strength on the surface of the leg muscles at the angle,and the analysis verifies the effectiveness of the gravity support function.The data analysis results show that the rectus femoris power of the rectus femoris when sitting at 30° and 90° is compared with that when the sitting position is only maintained by itself.The mean strength was reduced by 10.8% and 18.4%,respectively,the mean strength of the vastus lateralis muscle was reduced by 49.4% and 24.36%,and the mean strength of the tibialis anterior muscle was reduced by 47.2% and 73.76%.