Granular-Elastomer Hybrid Jamming Media for Complex Shape Soft Variable Stiffness Actuator

Abstract

Soft variable stiffness actuators have received considerable attention in the field of soft robotics due to their ability to exhibit both high shape adaptability and high load-bearing capacity. Soft variable stiffness actuators provide a high degree of versatility for a wide range of applications by allowing stiffness to be adjusted according to the situation. However, current stiffness tuning methods for soft robots have limitations such as directional stiffness and limiting achievable geometry. To address these limitations, we propose to use granular-elastomer hybrid jamming media for soft variable stiffness actuators. This proposed method offers isotropic stiffness variability, allowing greater degrees of freedom in shape realization. Additionally, the elastomeric domain which fills the gap between the granular provides deformability regardless of their stiffness state, and actuators can change their stiffness without changing their volume. The proposed actuator can change stiffness up to 11 times in both tensile and bending directions and can accommodate continuous deformation such as bending and torsion. The ability to exhibit both high shape adaptability and high load-bearing capacity in a single actuator makes it a promising candidate for integration into a wide range of atypical soft robots.