A soft wearable robot for the shoulder: Design, characterization, and preliminary testing

TLDR

The textile-based approach offers a lightweight, low‑profile, comfortable, and non‑restrictive design that can be easily donned like clothing. The study presents a soft wearable robot for the shoulder intended to help individuals with neuromuscular conditions perform daily activities. The device employs two custom textile pneumatic actuators—an axillary actuator for abduction and a pair of smaller actuators for horizontal flexion/extension—whose performance was experimentally evaluated and then integrated into a garment, with human subject tests measuring muscle activity differences between powered and unpowered states. The actuator folds flat when not in use, making the robot nearly invisible under clothing and potentially reducing stigma, while preliminary tests show large reductions in targeted muscle effort, demonstrating feasibility and promise.

Abstract

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 textilebased 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.