The Control Method Research Of The Bed-type Lower Limb Rehabilitation Robot

With the vigorous development of the society and medical technology,the trend of population aging is speeding up year by year.The incidence of various neurological diseases is also increasing.The cerebral stroke is one of the most common neurological diseases,about seventy to eighty percent of them will be disabled so that they need accept rehabilitation treatment.If they accept rehabilitation treatment earlier,the results will be better.Physical disability is one of the highest rate of all disabilities,so it is important that the patients with physical disabilities should take timely rehabilitation.To solve the above problem,we design the bed-type lower limb rehabilitation robot with many training methods to help patients with physical disabilities.We also set the robot control system and put forward the control method of active control and passive control.First,we summarize the technical features and development trend of lower limb rehabilitation training robot at home and abroad.The human standard walking gait trajectory is collected by Motion Analysis and then it will be filtered and fitted.This lay a theoretical foundation for control method of active control and passive control of limb rehabilitation robot.Robot kinematics model is established based on lower limb rehabilitation robot.The robot kinematics equation is also established to analyze the dynamic relationship of angle and angular velocity between hip and knee of the robot.At the same time,man-machine simplified dynamic model is set up and the robot dynamic equations are built through Lagrange method.Then the dynamic simulation based on Solidworks Motion is used to provide theoretical basis for the choice of motor model and the research of control method.Second,combining with the characteristics of the mechanical structure of this robot,we put forward the control method of active control and passive control to satisfy the requirement of the patients with different stages of rehabilitation training.In the early stage of the rehabilitation training,we use the fuzzy PID control based on servo motor to assist patients to achieve constant speed trajectory of rehabilitation training.Then Simulink simulation is used to verify that the fuzzy PID has the faster response and smaller overshoot amount then the conventional PID.In the late rehabilitation training,fuzzy adaptive impedance control is used.We establish the fuzzy rule table of different ways of rehabilitation training through the absolute average active reaction of ham and crus so that the impedance parameters can update online once per cycle to ensure real-time active rehabilitation training.At last,the robot control system is established and we complete the robot hardware system integration,software design and touch screen interface design.We verify the feasibility and safety of the robot by no load functional experiments and determine the test way of rehabilitation training through the measurement of the contact force with the experiment.To accurately extract the human-computer interaction active reaction,we design contact force collection structure with new type of flexible hinge and pressure sensors.The rationality of mechanism design is verified by finite element analysis.In the end,we complete the passive training experiment based on the fuzzy PID control and the active training experiment based on fuzzy adaptive impedance control experiment to verify the feasibility of robot control algorithm and meet the basic requirements of rehabilitation training.