Design considerations for an active soft orthotic system for shoulder rehabilitation

Strokes affect over 750,000 people annually in the United States. This significant and disabling condition can result in paralysis that must be treated by regular sessions with a dedicated physical therapist in order to regain motor function. However, the use of therapists is expensive, in high demand, and requires patient travel to a rehabilitation clinic. We propose an inexpensive and wearable upper body orthotics system that can be used at home to provide the same level of rehabilitation as the current physical therapy standard of care. The system is composed of a soft orthotic device with an integrated cable actuation system that is worn over the upper body, a limb position sensing system, and an actuator package. This paper presents initial design considerations and the evaluation of a proof of concept system for shoulder joint rehabilitation. Through simulations and experimental evaluation, the system is shown to be adjustable, easily wearable, and adaptable to misalignment and anatomical variations. Insights provided by these initial studies will inform the development of a complete upper body orthotic system.