Abstract
We have many small diameter pipes that are cooling pipes for atomic power stations, boiler pipes, and gas or water pipe lines. They must be periodically inspected in order to protect the accident previously. Diameters and T-junctions of these pipes are different at the place where pipes change from the main to the branch. The inspection microrobot for these pipes must move different diameter and T-junction. The fabricated mobile microrobot was confirmed to move in different diameter pipes and T-junction whose diameters are between 44 mm and 90 mm. Its speed was 24 mm/s.
