a Soft Hand Exoskeleton With a Novel Tendon Layout to Improve Stable Wearing in Grasping Assistance

: We present a novel soft exoskeleton providing active support for hand closing and opening. The main novelty is a different tendon routing, folded laterally on both sides of the hand, and adding clenching forces when the exoskeleton is activated. It improves the stability of the glove, diminishing slippage and detachment of tendons from the hand palm toward the grasping workspace. The clenching effect is released when the hand is relaxed, thus enhancing the user's comfort. The alternative routing allowed embedding a single actuator on the hand dorsum, resulting more compact with no remote cable transmission. Enhanced adaptation to the hand is introduced by the modular design of the soft polymer open rings. FEM simulations were performed to understand the interaction between soft modules and fingers. Different experiments assessed the desired effect of the proposed routing in terms of stability and deformation of the glove, evaluated the inter-finger compliance for non-cylindrical grasping, and characterized the output grasping force. Experiments with subjects explored the grasping performance of the soft exoskeleton with different hand sizes. A preliminary evaluation with Spinal Cord Injury patients was useful to highlight the strengths and limitations of the device when applied to the target scenario

Design and Development of a Hand Exosuit for Rehabilitation and Assistance in Spinal Cord Injuries

This thesis presents a novel hand exosuit for rehabilitation and assistance in Spinal Cord Injuries (SCI). The developed prototype was designed with three distinctive features: a) the actuation of the exoskeleton is based on four-tendon model, which simulate the four groups of tendons inside fingers; b) all its components are compact on the back of the hand without taking up space on the patient's forearm, this allows the portability of the device and makes it suitable for personal patient assistance; c) its finger motion units are composed of a series of flexible open rings and a thimble on the fingertips all crossed by four cables for the actuation, this makes the units modular and adjustable according to the length of the patient's fingers. The design and development were carried out at the PERCRO laboratories of the Scuola Superiore Sant'Anna. A first characterization of the prototype was carried out on the basis of grasping force and grasping pressure. Then, a preliminary experimentation was carried out at the Careggi Hospital in Florence on some patients suffering from SCI with motor disabilities in the hands