A Soft Wearable Robot for the Shoulder: Design, Characterization, and Preliminary Testing

In this paper, we present a soft wearable robot for the shoulder which has the potential to assist individuals suffering from a range of neuromuscular conditions affecting the shoulder to perform activities of daily living. This wearable robot combines two types of soft textile pneumatic actuators which were custom developed for this particular application to support the upper arm through shoulder abduction and horizontal flexion/extension. The advantage of a textile-based approach is that the robot can be lightweight, low-profile, comfortable and non-restrictive to the wearer, and easy to don like an item of clothing. The actuator's ability to fold flat when not in use allows the robot to be almost invisible under clothing, potentially allowing the user to avoid any stigma associated with using assistive devices in public. To abduct the arm, a textile-based pneumatic actuator was developed to fit within the axilla to push the arm upwards, while a pair of smaller actuators pivot the abduction actuator to allow for horizontal extension and flexion. The individual textile actuators were experimentally evaluated before being integrated into a wearable garment. Human subject testing was performed to evaluate the ability of the robot to assist the arm by monitoring changes in biological muscle activity when comparing the robot powered on and off. Preliminary results show large reductions in muscular effort in targeted muscles, demonstrating the feasibility and promise of such a soft wearable robot for the shoulder.