Design and Fabrication of Rehabilitation-based Exoskeleton for Paralytic Arm

Paralysis has affected almost 750000 people out of which 80% are left with one of their limbs weakened. Rehabilitation is the process of regaining the muscle movement by repeating the hand movement artificially. In this contemporary research, an Exo-glove and Exo-arm were fabricated and tested which will allow mobility and rehabilitation of fingers as well as the arm. Bowden cables are used to perform force transmission and are affixed to the fingers with the help of 3-D printed guides. The Exo-arm comprises a servo motor attached to a 4 bar link mechanism. The system is controlled by a joystick analog input. A 5kg-cm servo motor is used to actuate the fingers via the cable mechanism which enables flexibility. The cable is wound around a pulley of 9cm diameter and is mounted on the housing to maintain the tension of the cable. The arm was actuated using a 20kg-cm servo motor that drives the link mechanism and conveys a force to move the forearm. Testing of the Exo-glove and Exo-arm reveals the ease with which it can grasp and lift smaller objects. Implementing optimization in the design of the guide, using less-stranded wire, and high torque servo motor will widen the range of objects that can be grasped and raised. This will allow the smooth functioning of the system.