Design And Analysis Of A Post Operative Rehabilitation Robot For The Elbow And Wrist Joint

For postoperative patients with elbow and wrist fractures,highly repetitive rehabilitation training of the elbow and wrist joint is required,and an elbow and wrist rehabilitation robot is used to make up for the lack of manual training and reduce the workload of physicians.In order to solve the problem that the existing elbow and wrist rehabilitation robots cause patients’ discomfort due to the configuration limitation and low human-machine compatibility,this paper combines rehabilitation medicine and ergonomics to propose an elbow and wrist rehabilitation robot for post-operative elbow and wrist patients.Firstly,based to the anatomical structure of human elbow and wrist joint and rehabilitation medical theory,the elbow and wrist rehabilitation robot is proposed to meet the requirements of rehabilitation in accordance with the motion mechanism of elbow and wrist joint.Considering that the misalignment of human-machine axis is likely to cause secondary injury to patients,the joint misalignment compensation mechanism and ropedriven wrist parallel mechanism are designed to passively compensate the joint misalignment by analyzing the motion characteristics of elbow and wrist joint to ensure the comfort and safety of patient rehabilitation.Secondly,the kinematics of the elbow-wrist rehabilitation robot is analyzed,the inverse kinematics of the wrist parallel mechanism is solved based on the kinematic model of the elbow-wrist rehabilitation robot,the relationship between the wrist joint angle and the length of each driving rope is derived,and the kinematics of the wrist parallel mechanism is combined with the statics to determine the stiffness of the compression spring in order to improve the flexibility of the robot,and its theoretical work is obtained based on the inverse kinematic solution of the wrist parallel mechanism The theoretical working space was obtained based on the inverse kinematic solution of the wrist parallel mechanism.Then,for the postoperative elbow and wrist rehabilitation,the modes of different rehabilitation stages are analyzed,the passive rehabilitation strategy based on fuzzy PID control and the active rehabilitation strategy based on position-based impedance control are proposed,the influence of impedance parameters on the performance of the control system is analyzed,and the control system design of the elbow and wrist rehabilitation robot is carried out to develop a human-machine interaction interface that is convenient for physicians and patients to operate and to improve the intelligence of the elbow and wrist rehabilitation robot services.Finally,in order to ensure the position tracking accuracy of the elbow and wrist rehabilitation robot,a virtual prototype dynamics model was established to analyze the robot’s driving rope tension and to conduct tracking simulation experiments on the rehabilitation trajectory of the elbow and wrist rehabilitation robot,and the experimental results showed that the actual trajectory basically matched the desired trajectory and the trajectory error was within a reasonable range,which verified the rationality of the robot’s structural design and the effectiveness of the control strategy.