Conceptual Design and Characteristics of a New Wrist Rehabilitation Exoskeleton Based on Systematic Approach

Abstract

In order to speed up the recovery process of stroke or spinal cord injury patients with impaired wrist movement, rehabilitation exercises are recommended. The use of exoskeleton robots for wrist rehabilitation has been highly regarded by researchers because they offer excellent maneuverability, can be controlled separately by each joint, and can interact with the patient well due to their wearability. Creating cost-effective, lightweight, and comfortable devices would enhance their suitability for home-based use, significantly reducing the patient’s treatment duration. In this study, the aim is to design a rehabilitation exoskeleton with a simple structure, a lightweight design, and a maximum level of comfort. This robot has been designed using a systematic approach in order to obtain the most optimal solution for all functional requirements and design specifications. In this rehabilitation robot, there are three active degrees of freedom (DOF), which allow it to perform pronation/supination (P/S), abduction/adduction (AB/AD), flexion/extension (F/E) movements, and two passive DOF, which allow the instantaneous center of rotation to be changed, as well as the rotation axis to adapt to two DOFs, AB/AD and F/E. Lastly, the forward kinematics of the robot has been examined using the Denavit-Hartenberg method in order to observe the workspace of the robot and ensure its kinematic performance. Based on the results, the designed robot covers 94.9% of its maximum range in the F/E DOF and can fully utilize its movement capabilities (100%) in two DOFs P/S and AB/AD. Its maximum range of motion in all DOFs is wider than the range required for patients to perform their daily activities, so this robot can perform rehabilitation exercises fully.