Fish-tail inspired soft pneumatic glove for hand rehabilitation: design, characterization, and control

Abstract Soft pneumatic rehabilitation gloves offer inherent safety and comfort, making them a preferred solution for hand rehabilitation in stroke patients due to their unparalleled advantages. The output characteristics of soft pneumatic actuators (SPAs) critically determine the training efficacy and application potential of these gloves. However, conventional SPAs suffer from limited normal pressure output and poor directional bending capabilities, significantly constraining their utility. Inspired by the superior locomotion of fish tails, this study proposes a rigid-flexible coupled hyperbolic SPA (HSPA). The pneumatic network of the HSPA incorporates hyperbolic chambers that closely mimic the streamlined profile of a fish’s dorsal structure. The gradually expanding cross-section and variable-curvature geometry of these chambers guide deformation trajectories during inflation, enabling high-precision directional bending. This design enhances force density along the bending axis while preventing torsional deformation—common in uniform-curvature SPAs under high impedance—that risks injuring patients’ fingers. The HSPA’s constraining layer employs a rigid-flexible coupling strategy, embedding a bionic fishbone structure to substantially augment fingertip normal pressure and joint torque. To promote neural remodeling in stroke patients, our pneumatic rehabilitation glove integrates multimodal training strategies: pre-programmed rehabilitation, mirror therapy, and active rehabilitation driven by motion intention recognition via electromyography signals. Experimental validation and wearability assessments confirm the HSPA’s high directional bending accuracy and superior force output. The developed glove demonstrates significant promise in facilitating post-stroke rehabilitation and assisted grasping tasks.