Design And Simulation Of Passive Training Mode Control System For Foot-operated Lower Limb Rehabilitation Device

With the increasing number of patients with lower limb hemiplegia caused by population aging,stroke and other factors,rehabilitation medical resources have been unable to meet the needs of patients.It is urgent to develop rehabilitation aids to reduce the dependence of patients on medical staff.Home rehabilitation aids can not only alleviate the shortage of medical resources,but also reduce the rehabilitation cost of patients and facilitate their home treatment.At present,the passive training mode of pedal lower limb rehabilitation equipment is mainly controlled by traditional PID(Proportion、Integral、Derivative),and its control performance is mainly affected by PID control parameters.The traditional PID parameter tuning mainly relies on experience for debugging.The process is cumbersome,and there are problems such as long adjustment time,poor dynamic performance,and insufficient stability.If the lower limb rehabilitation equipment deviates from the set speed,it is easy to cause secondary damage to the patient’s affected limb.Therefore,this study uses intelligent algorithms to set PID parameters,so that the crank speed of the pedal lower limb rehabilitation device can respond quickly,and can keep the crank speed stable in a shorter time,which is of great significance to ensure the safety of patients’ lower limb passive training and improve the effect of rehabilitation training.This paper first analyzes the structure of human lower limbs and the principle of lower limb rehabilitation medicine,and clarifies that patients can recover the motor function of the affected limbs faster with the help of pedal lower limb rehabilitation equipment.According to the selection requirements of rehabilitation training equipment,a foot-type lower limb rehabilitation equipment that meets the requirements is selected as the research object of this paper,which lays a foundation for the establishment of the subsequent human-machine system model.Then,based on the analysis of the training preparation,training content and rehabilitation effect evaluation of the passive training mode of lower limb rehabilitation,the human lower limb model is simplified through the analysis of the lower limb movement process.Combined with the rehabilitation principle of foot-type lower limb rehabilitation equipment,a human-machine integrated rigid body connecting rod model is established.Then,the kinematics and Lagrange dynamics equations of the man-machine system model are established,which provides theoretical support for Adams dynamics modeling and joint simulation.On the basis of theoretical analysis,an improved GWO(Grey Wolf Optimization)-PID controller is designed by introducing the improved grey wolf algorithm,and the PID parameters are tuned by the controller.Finally,the GWO-PID control system module is built in Matlab / Simulink,and the improved grey wolf algorithm program is written to optimize the control parameters of the PID controller.At the same time,the dynamic model of the man-machine system is established in Adams to realize the joint simulation of Adams and Matlab / Simulink.The simulation results show that the improved grey wolf optimization algorithm takes into account the global search ability and local development ability well.Compared with the traditional trial and error PID control and the standard GWO-PID control,the improved GWO-PID control has better dynamic performance and stronger stability.It can realize the precise control of the human-machine system of lower limb rehabilitation,and can better meet the passive rehabilitation training needs of patients’ lower limbs.