Grounded upper limb exoskeletal rehabilitation robot

Abstract

The increasing average age of the world population enhances the importance of using rehabilitation robots in the physiotherapy of patients who have lost limb motor functions. Due to the anatomical complexity of the shoulder joint, current rehabilitation robots are not sufficient to perform exercises focusing on the shoulder area. In addition, since most of the robots on the market do not have an adjustable structure, it is very difficult for patients with different body sizes to use the same robot for their therapeutic exercises. In this study, the design, production, and control of an adjustable 4-DOF grounded upper limb exoskeletal rehabilitation robot for the elbow and shoulder area which can be used by elderly, stroke, or Parkinson patients were performed. The mechanical structure of the robot is capable of making three active shoulder movements and one passive elbow movement. These movements are; shoulder vertical flexion-extension, shoulder horizontal flexion-extension, shoulder abduction/adduction, and elbow flexion-extension. A low-cost electromyography (EMG) device was developed to measure muscle activation and control instantaneous muscle activation. In addition, a user-friendly human-machine interface was developed where patient information can be entered and exercise types and movement selections can be made. The developed robotic exoskeleton can perform 4 different therapeutic exercises: passive, active-assistive, isotonic, and isometric. While the PID control method is used for passive exercise, position-based and force-based impedance control systems were developed to ensure efficient human-robot interaction in active assist, isometric modes, and isotonic exercises. The experimental results were presented in terms of simulation and the real system for the passive, active-assistive, isotonic, and isometric exercises. According to the experimental results, the developed rehabilitation robot efficiently performed these therapeutic exercises.