Abstract
This paper deals with a new inspection robot imitating a green caterpillar. Gas or water pipes for individual or corporate houses and boilers or hot water pipes for industries are settled in the ground or in the narrow spaces and some of them are covered by casings or hard heat insulators. So, it is very difficult to inspect from outside of the pipe. However, we are easy to inspect the pipe from inside of the pipe. Conventional inspection robots imitating an earthworm and inchworm could not move in different diameter pipe and could not generate large traction force. The green caterpillar sticks a passage such as the leaf by its prolegs. The new inspection robot can move in the pipe whose diameters are from 70 mm to 100 mm, generating the traction force of 17.6 N.
