Parameter Selections and Applications for Soft Bellows Actuators (SBAs) with Various Performance Metrics

Abstract

Soft bellows actuators (SBAs), a particular type of soft pneumatic actuators (SPAs), are widely used in various applications, such as climbing robots, industrial grippers, and wearable devices. Despite their advantages of uniform motion and high efficiency, the design of SBAs often relies on experiential methods rather than standardized guidelines. This results in unclear optimization pathways and a misalignment between SBA performance and specific application requirements. This study identifies six critical parameters of linear pneumatic SBAs: Shore hardness (SH), number of units (N), thickness (t), mid-diameter (R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf>), unit width (x), and unit depth (h). We explore how these parameters influence load capacity, displacement efficiency, and bending resistance. Experimental findings indicate that increasing SH, t, x, and h and decreasing N enhance load capacity. Moreover, increases in N, R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf>, x, and h, along with decreases in SH and t, improve displacement efficiency. Furthermore, enhancing SH, t, and R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> and reducing N, x, and h strengthen bending resistance. Based on these insights, we design three types of SBAs tailored to specific tasks, which are implemented in a high-load pneumatic gripper, a high-efficiency displacement table, and a pneumatic worm-inspired climbing robot. This research contributes to the targeted design of SBAs, offering a novel approach for the effective optimization and performance prediction of particular SPAs, thereby facilitating the broader application of soft robots.