Research On Iterative Learning Control Of Omnidirectional Rehabilitative Training Walker

With the increasing of the elderly population,the number of patients with limb injury and lower limb movement disorder caused by accidents increases year by year,making the rehabilitation walking training robot widely used.For the tracking control problem of rehabilitation walking training robot,many domestic and abroad scholars have adopted a variety of control methods.However,in the research process,most of them ignore that rehabilitation training is a repetitive movement process and the problem of velocity error constraint is not considered,so the ideal accuracy of the tracking control effect cannot be achieved.In this thesis,for the problems including forgetting factor,incomplete feedback information and velocity error constraint,the trajectory and velocity tracking of rehabilitation walking robot are controlled by iterative learning control.The main contents are as follows:Due to the variation of user quality and the partial forgotten information generated during the repeated learning process within the system,the tracking accuracy of the robot can be affected.In this dissertation,the dynamic model of rehabilitation walking training robot is analyzed,and an iterative learning controller with forgetting factor is designed based on the iterative learning control method.On basis of learning partial content,the iterative learning can be completed by the controller,the influence of user quality variation and forgotten information on the system can be eliminated.And the results of simulation shows that the iterative learning controller with forgetting factors can realize the rehabilitation walking training robot tracking to designed path accurately.Because of sensor aging and data transmission errors,the feedback information of the system is incomplete.Therefore,the iterative learning controller designed is improved to eliminate the reverse influence of incomplete feedback information on the robot system.The stability of the closed-loop system is proved by Lyapunov method and the reliability of the proposed algorithm is verified by MATLAB simulation.Aiming at the issue of velocity error constraint,a predict model of rehabilitation walking training robot is built,and by predicting the speed error obtained by the control,as an input of the iterative learning controller,an iterative learning controller with speed error constraint is obtained,which realizes the accurate tracking of the motion trajectory and speed of the rehabilitation walking training robot.The contract results of simulation show that the iterative learning controller with velocity error constraint designed can effectively improve the control accuracy of the rehabilitation walking training robot.