Development Of Control System For Planar Upper Limb Rehabilitation Robot

With the rapid development of rehabilitation medical equipment,rehabilitation robot,as an auxiliary automation equipment for the recovery of limb motor function of patients,its intelligent medical characteristics have gradually become the focus of research.In order to meet the rehabilitation training needs of different patients,the intelligent control of rehabilitation robots has become one of the research focuses.Aiming at the desktop upper limb rehabilitation robot,this paper designs intelligent control strategies for different patients’ rehabilitation training needs in different periods,so as to ensure the effect of patients’ rehabilitation training.In this paper,the kinematics model is established based on the overall structure of the upper limb rehabilitation robot.The dynamic motion law of the robot is derived by Lagrange method.Combined with the three-dimensional space model,a simulation platform is established to provide an experimental platform for the subsequent control algorithm verification.In order to improve the control accuracy of passive training,this paper first adopts the PID control method based on neural network.The dynamic identification ability of neural network is used to adjust the traditional PID parameters adaptively,and the purpose of improving the control accuracy of nonlinear model is realized.Secondly,the method of calculating torque based on dynamics based on ANN is adopted,and the neural network is used to approximate the model of nonlinear system,so as to improve the problem of inaccurate model and realize the compensation of dynamic model.Finally,through the comparative test analysis on the simulation platform,the RBF-PID control method with better trajectory tracking control effect is selected.In order to solve the problem that the passive training in the early stage can no longer meet the needs of patients ’ rehabilitation training when the patients have the consciousness of autonomous motion in the later stage of rehabilitation,a control scheme with impedance control as the core is proposed.Through the conversion between position error and force error,the motion trajectory of the upper limb robot is adjusted to make it have certain flexibility in motion.In this paper,force-based and position-based impedance control schemes are adopted respectively.Based on the analysis of feasibility,simulation experiments are carried out.Through the analysis of simulation results,the control method optimization of upper limb rehabilitation robot is studied.Finally,in order to prove that the parameters of impedance control have a disturbance effect on the experimental results,the impedance control parameters are quantitatively analyzed.Passive control and active control experiments are carried out on the built prototype experimental platform.The passive experimental results show that the trajectory tracking accuracy based on RBF-PID can meet the early rehabilitation training.The active experimental results show that the desired trajectory can be corrected by the control of contact force during human-computer interaction,and the compliance control during human-computer interaction can be realized.