Research On Exoskeleton Control System For Human Function Enhancement

In recent years,with the aging of the population,the number of people with weak lower limbs is increasing;With the development of robot related science and technology,the technology related to lower limb rigid exoskeleton is also gradually mature.It can be effectively used in the field of human function enhancement,and has more and more research and application in the field of power assistance and rehabilitation.The lower limb exoskeleton needs to ensure stability and comfort when it is used.This paper conducts a series of studies on exoskeleton used in the field of human function enhancement.The main contents are as follows:(1)In the motion control part,according to the hardware structure of the exoskeleton,the dynamic model is established,and the dynamic parameters are identified,then the minimum dynamic parameter set is obtained;The dynamic feedforward compensation is established,and the impedance control strategy based on dynamic feedforward is constructed.(2)In the stability planning part,the centroid of the human-machine coupling model is calculated to build a linear inverted pendulum model.On the one hand,the force control of the bottom layer can be based on stability compensation;on the other hand,the landing point can be planned to determine the target value of each step,so as to achieve the purpose of stability planning.(3)In the gait trajectory planning part,an online gait trajectory planning method and control strategy based on dynamic movement primitives are proposed.First,it can use the plantar pressure to do phase segmentation to identify the motion intention,and then determine the landing point position according to the linear inverted pendulum model,then use the inverse kinematics solution to plan the target angle of each joint,use the dynamic movement primitives to plan the gait in real time,and control the external skeleton according to the control strategy according to the generated curve.At the same time,it can also conduct online learning on the previous gait to obtain the best learning gait.Finally,the algorithm is validated by using the 6-DOF lower limb rigid exoskeleton described in the paper.The results show that the algorithm proposed in this paper can effectively carry out real-time online learning and generation of gait trajectory according to the transformation of gait phase,and the generated gait curve has strong generalization ability,while ensuring a certain degree of motion stability.After analyzing the EMG signal,using the control algorithm proposed in this paper,the lower limb exoskeleton can effectively reduce the strength provided by the muscle during exercise.