Design And Implementation Of Control System For Parallel Hip Joint Rehabilitation Robot

Rehabilitation robots are medical devices developed through automation in the medical field,mainly used to provide standardized rehabilitation training for patients with skeletal muscle rehabilitation needs such as hemiplegia.The lower limb hip joint,as an important joint in various human movements,is particularly important for rehabilitation training.However,rehabilitation training is closely related to the patient’s condition,posing challenges to robot control.In addition,as a three degree of freedom spherical joint,the hip joint has corresponding muscle groups for each degree of freedom,which requires tracking of each degree of freedom and complex motion.Therefore,this article researches the implementation of rehabilitation institution control systems and trajectory tracking algorithms.Firstly,based on a single leg 3-RRPS parallel hip joint rehabilitation mechanism,a virtual prototype modeling is conducted.The mechanism is symmetrically distributed on the left and right legs,with each leg containing 3 branch chains and connected to the human leg at the end.It can perform movements such as flexion and extension,abduction and adduction,and internal and external rotation.The virtual prototype was used to verify its range of motion,and the coordinate system of the mechanism was established.Based on the coordinate system,the closed vector method was used to establish the man-machine forward kinematics model and the inverse kinematics model.Based on MATLAB,the forward kinematics solution and Adams were used to verify the inverse kinematics solution of the man-machine system,and the correctness of the inverse kinematics model was verified.Based on the inverse kinematics model,the motion coupling performance of humanmachine system kinematics is explored.Secondly,hardware selection was carried out based on the 3-RRPS parallel hip joint rehabilitation mechanism,and the circuit design of the drive control power supply circuit and current monitoring unit was completed.The communication network of the parallel hip joint rehabilitation mechanism was established,and the physical prototype experimental platform for the parallel hip joint rehabilitation robot was built.We have designed programs for manual and automatic rehabilitation,and based on the lower computer experimental platform and rehabilitation training needs,we have designed the upper computer interface using Qt.Finally,based on the established inverse kinematics model,a fuzzy adaptive PD algorithm structure is proposed to overcome the shortcomings of conventional PD control in terms of rapidity and stability in nonlinear systems.The proportion and differential coefficients are adaptively adjusted by the fuzzy controller,which is verified by single motor simulation.The results show that the fuzzy adaptive PD has better tracking performance.In addition,the established Adams model is used for kinematics trajectory tracking simulation to verify the controller’s attitude trajectory tracking performance.In order to obtain a better nonlinear trajectory tracking effect,the motor model is obtained through system identification,and a fuzzy adaptive PD controller with fuzzy feedforward compensation is designed.Its effectiveness is verified through experiments.In addition,the fuzzy adaptive PD controller based on feedforward compensation conducted flexion/extension rehabilitation training and abduction/adduction rehabilitation training experiments,collected gait trajectory data and completed rehabilitation training experiments with reference gait trajectory.Branch angle tracking and motor torque information show that the rehabilitation mechanism can meet the design requirements.