Upper-Limb Powered Exoskeleton Design

Abstract

An exoskeleton is an external structural mechanism with joints and links corresponding to those of the human body. With applications in rehabilitation medicine and virtual reality simulation, exoskeletons offer benefits for both disabled and healthy populations. A pilot database defining the kinematics and dynamics of the upper limb during daily living activities was one among several factors guiding the development of an anthropomorphic, 7-DOF, powered arm exoskeleton. Additional design inputs include anatomical and physiological considerations, workspace analyses, and upper limb joint ranges of motion. The database was compiled from 19 arm activities of daily living. The cable-actuated dexterous exoskeleton for neurorehabilitation (CADEN)-7 offers remarkable opportunities as a versatile human-machine interface and as a new generation of assistive technology. Proximal placement of motors and distal placement of cable-pulley reductions were incorporated into the design, leading to low inertia, high-stiffness links, and backdrivable transmissions with zero backlash. The design enables full glenohumeral, elbow, and wrist joint functionality. Potential applications of the exoskeleton as a wearable robot include: 1) a therapeutic and diagnostics device for physiotherapy, 2) an assistive (orthotic) device for human power amplifications, 3) a haptic device in virtual reality simulation, and 4) a master device for teleoperation.