A Flexible Wearable Glove with Extendable Segmented Fabric-Based Bellows Actuators (ES-FBAs) for Hand Rehabilitation

Considering the high repetition and strong interactive nature of the rehabilitation process, the design of hand-assisting robots should prioritize not only high force output but also coordination and cooperation with the human hand. In this paper, inspired by the segmented motion patterns of the human hand and the mechanisms of skin stretching, we propose an extendable segmented fabric-based bellows actuator (ES-FBA), designed for assisting in finger flexion of stroke patients, comprising innovative fishing line elastic bands, elastic velcro fasteners, and a TPU bladder. The key feature of the ES-FBA is its bending deformation, which aligns with the natural bending motions of the human hand. Moreover, its unique extension-limiting layer adapts to skin stretching and facilitates modular integration. The optimal number of folds at the actuator's joints is determined through structural optimization. Our investigation into the extension capability and output force performance of the ES-FBA reveals its ability to achieve a maximum extension of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{61.8}\pm \mathbf{1.50}\%$</tex> at the joints and generate a tip-blocked force of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{15.29}\pm \mathbf{0.11}\mathbf{N}$</tex> under conditions of 25% extension and 150 kPa. Meanwhile, we also showcase a quick integration example of a wearable glove fitted with the ES-FBAs and evaluate its ability to assist in finger flexion. Building on this, the potential applications of the wearable soft glove in hand rehabilitation scenarios are explored, with demonstrations of rapid actuator swapping and assistance in grasping objects of varying weights.