Bionics-Inspired Soft Exoskeleton Enabling Physiological Hand Motion in Poststroke Rehabilitation: Design and Validation

A critical design objective for poststroke motor rehabilitation device is to replicate natural motion, which is essential for promoting neuroplasticity. In this article, the soft-exoskeleton (S-EXO), a bionics-inspired compliant hand exoskeleton, was designed to assist stroke survivors’ functional motions during their rehabilitation training. The S-EXO system consists of a wearable module (78 g), a compact actuation unit, and intuitive smartphone interfaces. The S-EXO system uses tendon-driven mechanism to realize the flexion motion of each finger, whereas the extension motion is driven by arch-shaped plate releasing elastic potential energy. We presented a new Y-shaped tendon design that allows the thumb to flex and rotate simultaneously, saving valuable hand space while reducing operational complexity. The system was evaluated on eight stroke subjects with low-to-moderate spasticity. With S-EXO system, all three types of pinches (tip, key, and palm) achieved average forces exceeding 10 N. Motion capture analysis confirmed that the Y-shaped tendon design effectively restored the mobility of the thumb's carpometacarpal joint. Standardized clinical evaluation further demonstrated that S-EXO leads to immediate enhancement of functional grasping performance.