Design and Evaluation of a Bidirectional Soft Glove for Hand Rehabilitation-Assistance Tasks

Abstract

Soft pneumatic gloves are a promising tool for assisting stroke patients with hand dysfunction in their rehabilitation and daily activities. However, current gloves have limited extension force output. This article presents a hybrid actuator that combines a silicone flexion actuator with an extension actuator made from shape memory alloy (SMA) springs. The Critical parameters and material of the soft actuator were optimized using a finite element model. Additionally, the SMA spring actuator was equipped with a water-cooling structure to reduce temperature and increase response speed by 55.8%. The hybrid actuator generated an obstructed tip force of 16.02 N at 200 kPa pressure and an extension force of 8.675 N. The hybrid actuator was integrated with the water-cooling structure into a soft glove and evaluated in trials involving eight stroke patients. With the assistance of the glove, the bending angles of the stroke patients' index fingers, including the PIP and MCP joints, significantly improved, increasing from 6.8 ± 2.8° and 11.3 ± 4.6° to 68.3 ± 5.3° and 68.1 ± 5.5°, respectively. Furthermore, the glove also increased the maximum friction with a 50-mm cylinder from 8.4 ± 3.5 N to 21.34 ± 5.8 N.