Design and analysis of a soft robotic glove for rehabilitation therapy

Abstract

Strokes often lead to hemiparesis of the hand. This renders individuals unable to actively flex or extend the affected hand’s fingers. Currently the only option for improvement is therapy to improve the neuromuscular connection and maintain ROM (Range of Motion). Conventional therapy is costly and time consuming. It involves in person visits and at home exercises. Soft robotics has a significant potential in rehabilitative and assistive exoskeletons. The flexible materials deliver a gentle, accessible therapy, minimizing possible injury and increasing the possibility of recovery. This research aimed to design and evaluate an optimized pneumatically actuated soft robotic glove for rehabilitative tasks which will execute the motion of the hand. While there are existing soft robotic gloves, this unique design will allow users to self-actuate their therapy through re-extending the hand using a layer of flexible steel. The resistive layer causes the fingers to return to a straightened position after the pneumatic actuator has released the air pressure which causes it to curl. This design underwent prototyping, evaluation, and human subject testing. This glove, tested by 10 unimpaired subjects, assisted in extension while minimally impairing the glove’s flexion performance. The actuations consistently achieved an average peak of 75° or greater during passive assisted motion. An addition of the steel layer lowered the blocked tip force by an average of 18.13% for all five fingers. The maximum blocked tip force with the steel ranged from 12.7-14.1 N. During passive assisted testing, participants accomplished 80.75% of their normal active flexion ROM when neglecting outliers with the steel lined glove. This data shows strong evidence that this glove would be appropriate to advance to human subject testing on those who do have post stroke hand impairments.