DESIGN AND DEVELOPMENT OF A ROBOTIC FINGER EXOSKELETON FOR REHABILITATION

Abstract

Current ROM (range of motion) rehabilitation is done by a therapist helping each patient individually, which can be done more effectively and efficiently by robotic devices. The goal of this work is to design and develop a robotic finger exoskeleton system as a CPM device for finger ROM rehabilitation. The research introduces a novel mechanism for finger exoskeleton design. The main concepts of the proposed design are having no interference and no translational forces on phalanges. The finger exoskeleton consists of 3 identical joint mechanisms which, for each, adopt a six-bar RCM as an equivalent revolute joint incorporating with 2 prismatic joints to form a close-loop mechanism with one anatomical joint. Cable and hose, known as Bowden cable transmission, is adopted to reduce burden from weight of driving modules. The prototype is driven by 3 motors moving flexion/extension of each joint individually, i.e. an MCP (metacarpophalangeal) joint, a PIP (proximal interphalangeal) joint and a DIP (distal interphalangeal) joint. The mechanism concept is preliminarily evaluated by simulation with the real anatomical joint trajectory. The simulation result shows that the mechanism can accommodate 2 adjacent phalanges at all configurations. The requirement based evaluation and the subjective test show that the device can move a subject’s finger with quite natural and unimpeded motion along the predefined path. The device is successfully tested with 14 healthy subjects.