Development of a new pneumatic-driven earthworm-like soft robot

Abstract

This paper presents the design and fabrication of a new pneumatic-driven soft robot which can imitate the crawling locomotion of an earthworm. The soft robot is consist of two soft actuators and three unidirectional crawling foots, all of which are fabricated by casting two-component RTV (room temperature vulcanized) silicone rubber in a three-dimensional (3-D) printed customized mold. The gait of the soft robot based on the simplified model of the earthworm's motion is designed. The soft actuator is composed of a cylindrical main body with a cylindrical chambers embedded in and a spring wrapping around the body. Since the spring limits the expansion in radial direction, the deformation of the soft actuator happens only in the axial direction by compressed air. The soft robot crawls faster and efficiently with the help of unidirectional crawling foots. The experiment shows that the soft robot can move forward continuously on condition of actuators expanding and contracting in a regular pattern.