High-Force Fabric-Based Pneumatic Actuators With Asymmetric Chambers and Interference-Reinforced Structure for Soft Wearable Assistive Gloves

Abstract

Fabric-based pneumatic actuators (FPAs) are promising in the design of soft wearable assistive gloves, owing to the lightweight and compliant advantages. However, the existing FPAs generally suffer from small output force, limiting users’ applications. This letter presents a new class of high-force FPAs (HFFPAs) that harness asymmetric chambers and interference-reinforced structure for soft wearable assistive gloves. Different from the classical FPAs with symmetric chamber (i.e., Line chamber) fabricated by two identical layers of textiles, we design FPAs with asymmetric chambers (i.e., Arch and Semicircle chambers) fabricated by two unidentical layers of textiles. To further improve the output force, we introduce interference pads on adjacent-pleat surfaces to reinforce the stiffness of the FPAs. We next characterize the joint torque and the tip blocked force of six kinds of FPAs (i.e., Line, Line-pad, Arch, Arch-pad, Semicircle, and Semicircle-pad FPAs). Experimental results demonstrate that the Semicircle-pad FPA shows the best performance, whose joint torque and tip blocked force are improved by 510% and 478% at 150 kPa than the commonly used Line FPA. We further integrate HFFPAs on soft wearable assistive gloves and verify the improved assistive capability in grasping multiscale objects with irregular geometry, covering a wide weight range (8–559 g) in activities of daily living (ADLs).