Caterpillar-inspired soft robot that locomotes upside-down by utilizing environmental skeleton

Abstract

Abstract Caterpillars do not process skeleton inside its body; instead, they utilize the environment, e.g., branches, to maintain the posture against gravity. This strategy is also beneficial for soft-bodied robotic artifacts, which allows us to simplify the body and control design. This paper presents a soft-bodied crawling robot able to locomote in an upside-down condition. The critical finding is producing tension in the soft body is necessary for the soft robot to realize environmental skeleton and robust locomotion, which is demonstrated with numerical experiments and the prototype, even when the weight is added. The design way can be useful for the other soft-bodied robots that have difficulties supporting the weight and maintain the posture under gravity, e.g., when climbing upside-down condition. The results shed new light on how to design a mechanical and control system for soft-bodied robots, e.g., electric wire/cable maintenance robot, a tree-climbing robot, and a viaduct monitoring robot.