Design Analysis and Experimental Validation of a New Flexible Layer Jamming-Based Soft Actuator

Abstract

Variable stiffness actuators based on jamming methodologies have been widely utilized in the field of soft robotics, enabling effective transitions between compliant and rigid states under varying operational conditions. This capability significantly enhances both stiffness modulation and gripping performance, thereby broadening the functional versatility and the application range. However, the existing jamming methodologies suffer some limitations including complex fabrication procedure, slow recovery response and high ultimate operating pressure. This article proposes a novel design of a flexible layer jamming-based pneumatically actuated soft actuator. The proposed actuator is composed of two stacked multi-chambers zigzag-shaped layers; namely, a driving chambers layer that enables actuator bending under applied pressure, and a jamming chambers layer that provides variable stiffness capability. Each jamming chamber contains equally spaced cantilever-like soft and thin layers that are tightly squeezed under vacuum to provide varied actuator's stiffness. Stereolithography (SLA) 3D printer is utilized to fabricate the actuator as a single integrated unit, aiming to relax the fabrication complexity and eliminate the need for any assembly process. A Finite Element (FE) simulations are carried out to explore the bending characteristics of the actuator, while complying with tensile strength and deflection. The experimental results validate the performance of the proposed actuator, demonstrating its capability to achieve a bending angle of up to 171°. Additionally, its payload capacity is confirmed through successful bending operation under a 100 g payload.