Design of a 3 Degree-of-Freedom Upper-Limb Active Exoskeleton with Cable-Driven Actuators for Neuromotor Rehabilitation

Exoskeletons are wearable mechanisms which, parallel to the wearer’s joints, modulate movements through active or passive torque application. While existing upper-limb exoskeletons offer benefits in strength augmentation and therapy, they often suffer from limited degrees of freedom and excessive bulk, hindering their utility in neuromotor rehabilitation. This study introduces a three degree-of-freedom active upper-limb exoskeleton optimized for neuromotor rehabilitation. Employing anthropometric data and rigorous kinematic analysis, the design accommodates elbow flexion/extension, forearm pronation/supination, and hand gripping. The upper limb dynamics, kinematics, and physiology were evaluated to provide adequate joint ranges of motion. Cable-driven actuators in the elbow and forearm joints were designed to provide low worn weight through the relocation of the motor units away from the user’s joints. The result is a lightweight, compact exoskeleton that provides optimal conditions for neuromotor rehabilitation. Finally, a preliminary control strategy was tested using myoelectric signals to trigger motion.