Verification of the Effect of Design Parameters on the Radius of Curvature of Vine-Like, Power Soft Gripper

We are developing a vine-Like, power soft gripper based on Euler’s belt theory to achieve high load capacity for grasping irregularly shaped heavy objects at disaster sites. This gripper consists of a fire hose with rubber sheets adhered to both sides and a spiral constant-force spring inserted inside. Initially coiled in a helical shape, it extends while increasing its radius of curvature when air pressure is applied. In this state, it approaches the target object and wraps around it when depressurized. Therefore, the inner diameter of the gripper in its initial state determines the minimum diameter of the object that can be grasped. Additionally, at present, the radius of curvature is small when pressurized, limiting its range of motion and restricting the objects it can grasp and its use in confined spaces. Hence, in this study, we have fabricated grippers with varying design parameters and experimentally verified the inner diameter in the initial state and the radius of curvature when pressurized. We fabricated grippers with varying stiffness of rubber sheets and constant-force springs, which are components of the gripper, and experimentally veri- fied their shape. The results show that the radius of curvature increases with increasing stiffness of the inner rubber sheet and decreasing stiffness of the constant-force spring. Additionally, it has been confirmed that the effect of the outer rubber sheet stiffness is sufficiently small.