Research On Rehabilitation Training Control Strategy Of Lower Limb Rehabilitation Training Robot

In recent years,the number of patients with lower limb motor dysfunction caused by stroke,traumatic brain injury,spinal cord injury and other diseases have been increasing day by day.Lower limb rehabilitation training robot can replace rehabilitation doctors to provide rehabilitation training for these patients,so it has received wide attention.The control strategy is the key to the realization of various rehabilitation training modes for the lower limb rehabilitation training robot,which has a great significance on the recovery of the lower limb motor function of patients.Therefore,in this paper,the lower limb rehabilitation training robot is the research object,its passive and assistive training control strategies are studied:(1)In order to make the rehabilitation training modes of the lower limb rehabilitation training robot more suitable for the rehabilitation needs of patients with lower limb motor dysfunction.Starting from the human anatomy and human kinematics,the movement characteristics of the human lower limbs were analysed,and clarify the joint movement mode of the human lower limbs,the range of motion of each joint,and the muscles involved in joint movement.By analyzing the rehabilitation training methods of patients with nervous system injury,the rehabilitation training mode of lower limb rehabilitation training robot is given.Based on the Brunnstrom motor function evaluation method and muscle strength evaluation method,the rehabilitation evaluation standard of patients with lower limb motor dysfunction was clarified.(2)The structural composition of the lower limb rehabilitation training robot is analyzed,and its simplified model is established.Through geometric method,virtual work principle and Lagrange method,the kinematics analysis,statics analysis and dynamics analysis of the lower limb rehabilitation training robot are carried out respectively.The forward kinematics equation,inverse kinematics equation,statics equation and dynamics equation of the lower limb rehabilitation training robot are given,which provides the model basis for the design of rehabilitation training control strategy.(3)Design a passive training control strategy of lower limb rehabilitation training robot based on feedforward control and fuzzy compensation.Based on the dynamic equation of the lower limb rehabilitation training robot,the feedforward control system is designed to obtain the feedforward joint torque,which is used to reduce the possible joint angle error.A fuzzy compensation control system based on fuzzy control is designed to get the joint compensation torque,which is used to compensate the uncertainty of the lower limb rehabilitation training robot.The joint simulation model of ADAMS and MATLAB/Simulink is established.It is proved that no matter whether there is modeling error and external interference the passive training control strategy can make the lower limb rehabilitation training robot drive the patient’s lower limb to move according to the planned joint angle with high precision。(4)A control strategy for assisted training of lower limb rehabilitation training robot based on impedance control is designed.Based on the principle of impedance control,the impedance control model of the lower limb rehabilitation training robot is established.The position-based impedance control method is used to give the assistant training control strategy.Based on the stress situation of the lower limb rehabilitation training robot when its bed is horizontal,a humanrobot contact force model of the thigh and calf was established.According to the need of solving the impedance formula,a method to convert thigh and calf humanrobot contact force into terminal human-robot contact force is given.Through the joint simulation model of ADAMS and MATLAB/Simulink,it is verified that when the lower limb rehabilitation training robot’ bed is horizontal,the assistant training control strategy can make the lower limb rehabilitation training robot move according to the planned joint angle while keeping the human-robot contact force of thigh and calf unchanged.The simulation experiment is designed by using the assisted training simulation model,and the influence law of impedance parameters on the human-robot contact force of thigh and calf is obtained,which provides a reference basis for the adjustment of impedance parameters.