Research On Motion State Constraint Control Method Of Rehabilitation Walking Training Robot

With the deepening of social aging,it has increased significantly that the number of patients with walking dysfunction caused by neurological diseases or musculoskeletal diseases.Traditional rehabilitation therapy has been unable to meet the needs of patients,which has prompted the unprecedented development of the rehabilitation walking training robots.In the training process,the robot needs to track the speed and trajectory specified by the doctor to assist the patient’s treatment.At present,many research results have been obtained for the tracking control of the rehabilitation walking training robot.However,these research results do not consider the simultaneous constraint control of speed and trajectory of the rehabilitation walking training robot.No matter the speed or trajectory,as long as it exceeds the safe range,it will weaken the effect of rehabilitation training and even cause harm to patients.Aiming at this problem,the motion state constraint control method of the rehabilitation walking training robot is studied.The main research contents are stated as the followings:Considering the influence of patients on the rehabilitation walking training robot,a dynamic model of the rehabilitation walking training robot with offset center of gravity is established.On this basis,in order to reduce the influence of external disturbance on the system,a disturbance observer based on radial basis function(RBF)is designed.For the problem that the unconstrained speed of robot will lead to the sudden change of speed.It is designed as a speed constraint controller for the rehabilitation robot based on the barrier Lyapunov function of natural logarithm(ln-BLF).Aiming at the problem that the uncoordinated speed of man-machine movement threatens the safety of trainers.It is designed as a speed constrained controller for each axis based on the barrier Lyapunov function of hyperbolic sine(sinh-BLF).The disturbance observer is used to improve the tracking performance of the controller and realize the speed constraints of each axis of the rehabilitation robot.The stability of the system is proved by Lyapunov Function,and the simulation shows that the speed of each axis of the robot is constrained in the safe range.Aiming at the problem that too large error of robot trajectory will also affect the safety of patients.Based on the velocity constraint,it is proposed as a motion state constraint control method with disturbance suppression function.The speed and trajectory of each axis of the rehabilitation robot are constrained simultaneously.The stability of the system is proved by Lyapunov function.Simulation results show that the proposed method can constrain the velocity and trajectory of each axis of the robot under disturbance.The security of man-machine system is guaranteed.