Research On Joint Actuator Control System Of Rehabilitation Exoskeleton Robo

The lower limb rehabilitation exoskeleton robot can assist people with reduced mobility to achieve normal gait movement,and the permanent magnet synchronous motor is applied to the exoskeleton joint drive control system because of its advantages of small size,low noise and high efficiency.At present,the position control of joint motor has some problems,such as low tracking accuracy and poor anti-interference ability,which can’t meet the servo control requirements of exoskeleton robot.In order to solve the related problems,the improved sliding mode control algorithm is used to improve the tracking accuracy of the joint motor to the position signal,and an extended state observer with differential adjustment is designed to observe and compensate for the related disturbance of the system,which improves the anti-interference ability of the system.Aiming at the difficulty in tuning many parameters of the control system,the sparrow search algorithm combined with Levy flight is introduced to tune the relevant parameters of the control system.The main contents of this thesis are as follows:(1)The model of joint motor control system is established and its vector control method and space vector pulse width modulation technology are introduced.(2)In order to achieve high precision position servo control of joint motor,a double closed-loop control strategy is proposed,the parameters of the current inner loop are adjusted,and the position-velocity outer loop is emphatically studied.An improved sliding mode control algorithm is proposed,in which an adaptive factor is introduced into the constant velocity term of the traditional exponential reaching law,and an integral sliding mode surface and a hyperbolic tangent switching function are selected,so that the sliding mode chattering is reduced and the dynamic response characteristics of the system are improved.(3)In order to meet the adaptability of exoskeleton to different patients and solve the problem that the control accuracy of the system is reduced due to interference such as time-varying load,a linear extended state observer with differential adjustment is designed to compensate for the related interference and improve the robustness of the system.(4)In order to solve the problems of long time of manual adjustment of parameters and poor control effect of parameter selection,the sparrow search algorithm combined with Levy flight is proposed to adjust related parameters in the control system.Finally,the effectiveness of the improved sliding mode control algorithm with disturbance observer is verified by simulation and related experiments.