Helical rotation in-pipe mobile robot

This paper proposes a helical rotation mobile robot for in-pipe inspection inspired by spirochetes, a kind of bacteria. The robot is flexible and has a simple structure. Its rolling motion is unlikely to damage the inner wall of a pipe. Therefore, it could be used to inspect a winding, flexible tube with a small diameter, such as a human intestine, in the future. This paper presents the principle of the helical rotation robot and analyzes the motion of an elastic body that is bent and rotated by the contraction and elongation of wires. A prototype is developed to verify the principle. It is driven by wires pulled by motors and pulleys. Preliminary experimental results show that the prototype can achieve helical rotating motion in a plastic tube.