Structural Design And Analysis Of A Flexible Wearable Knee Joint Actuator

As the problem of aging population intensifies and knee diseases increasingly affect the quality of life of the elderly,more and more people need wearable devices or rehabilitation assistance systems.Traditional rigid exoskeletons are heavy in weight and complex in structure,making it difficult to adapt to the multi-degree of freedom activities of the human body and affecting the comfort and flexibility of the wearer.In order to solve the inherent defects of rigid exoskeletons,this paper develops a wearable lower limb exoskeleton based on pneumatic folding actuators and pneumatic artificial muscles for knee joint assistance,which can provide assistance and rehabilitation functions for knee flexion and extension movements for people with lower limb weakness.This paper firstly analyzes the physiology and biomechanics of human lower limbs,and completes the design of wearable lower limb exoskeleton by designing a new folding actuator based on human physiological data and kinematic data,and innovatively applying two pneumatic actuators,pneumatic artificial muscle and pneumatic folding actuator,into the design of wearable lower limb exoskeleton,and verifying its driving performance through theoretical analysis and quasi-static test.The structural design of the wearable lower limb exoskeleton was completed by theoretical analysis and quasi-static test to verify the feasibility of the scheme.Then the pneumatic artificial muscles and folding actuators are combined with fabric knee pads to achieve the goals of wearability and comfort.Then,this paper designs the intelligent control system of the exoskeleton,including the control circuit,pneumatic circuit,feedback system,PID control algorithm and IMU posture recognition mode,to realize the intelligent control of the flexible exoskeleton.Finally,this paper evaluates the effect of the exoskeleton on knee rehabilitation assistance by using EMG signals through the wearing test of healthy individuals,and the results show that the mean,peak and sum of EMG signals of rectus femoris,medial femoris and lateral femoris are significantly reduced when the test subjects wear the device compared with those without the device,which verifies that the device can effectively provide knee extension assistance,and the combination of pneumatic artificial muscle and pneumatic folding actuator applied to actuate the exoskeleton is a feasible solution to provide rehabilitation assistance function for patients with lower extremity disorders.