Locomotion and turning patterns of a peristaltic crawling earthworm robot composed of flexible units

An earthworm moves by peristaltic crawling, which propagates extension and contraction waves along the anteroposterior direction from the anterior to posterior part, by varying the thickness and length of its segments. This locomotion mechanism is in contact with a large area on the ground when the robot moves. Furthermore, the amount of space required is less than that for other locomotion mechanisms. Therefore, this mechanism is suitable for not only rescue robots but also exploration robots in the ground and automatic endoscopic robots. In this study, we developed a peristaltic robot with a flexible feature actuated by servomotors. We proposed different turning patterns. In addition, we confirmed that the robot could move not only on a plane surface but also in a tube. The experiments revealed good performance.