Development of a soft robotic shoulder assistive device for shoulder abduction

Abstract

Cerebral Palsy (CP) is a perpetual disease that a patient endures throughout their entire lifetime. Motor impairment, that is a common symptom, must be permanently managed by the patient; however, evidence suggests that repetitive task practice (RTP) can help patients improve their motor skills. An initial version of a wearable, soft robotic, shoulder exosuit has been developed that may be used for RTP. The device is centered around an inflatable, fabric beam that facilitates abduction of the shoulder joint. The use of an inflatable beam has allowed the device to be extremely lightweight while still being able to deliver a considerable amount of bending moment. The actuator is initially in its deflated state; inflation of the actuator straightens it, applying a bending moment to the brachium that abducts the limb. Two overlapping sheets of fabric were hermetically sealed by applying localized heat at the edges. Actuators were then anchored to the shoulder and inserted to a sleeve attached to the brachium. Position control was achieved by applying varying magnitudes of pressure. Preliminary testing exhibited successful abduction on a mannequin and a healthy subject.