Origami-based Invaginatable Soft Vacuum Actuators with Optimized Creases that Avoid Bending Stress Concentration

摘要

We developed actuators that can be invaginated, combining a vacuum-pressure drive with a folding structure with durable creases, which were optimized by our proposed method.In this paper, we propose two types of prototype actuator: linear and bending.The advantage of invagination actuators is that the amount of deformation (i.e., linear deformation in the linear model and deformation angle of the tip in the bending model) can be increased and be determined at the design stage.The deformation results for this actuator showed that the total length becomes more than 50% smaller for the resting length of a three-modulus linear model, and the tip rotated 179.3° for the three-modulus bending model.The error between the design and the resulting deformation was less than 1%.In addition, the problem of bending stress concentration and rupture at the actuator's creases during folding deformation is alleviated by redesigning the shape of the creases through our proposed approach of optimizing the crosssectional crease shape.As a result, the fabricated actuator has shown a durability of more than 100000 actuation cycles.This actuator design will increase the applications of grippers and soft robots and improve the lifetime of the soft actuator.