A Wearable Upper Extremity Rehabilitation Device for Inducing Arm Swing in Gait Training

This paper presents the design and validation of a proof-of-concept prototype for a wearable rehabilitation device to incorporate arm swing during gait rehabilitation. Unlike current stationary exoskeletons used for rehabilitation of upper limbs' function, assisting arm swing during gait requires inducing faster arm flexion/extension movements while maintaining the users' arms unconstrained in other directions. We developed a portable and underactuated system with features such as a large workspace and backdrivability to induce arm swing. Its wide workspace allowed the wearers to easily move their arms in different directions without any constraints. A modified double parallelogram linkage (mDPL) is proposed to allow the device to mimic the natural workspace of an arm. Additionally, a pulley drive and weight compensation system were created to place the motor on the users' back reducing the hindering weight of the actuators on their arms. Our experiments demonstrated this arm-swing rehabilitator could successfully induce arm movements at different arm configurations with low (0.67 Hz) and high (1.1 Hz) frequencies corresponding to slow and fast walking.