Abstract
This paper discusses about mechanism improvement of a screw drive in-pipe robot that is with pathway selection mechanism. It can pass not only through straight pipes but also bent pipes and T-branches by changing three driving modes. These modes are performed by only two motors through a differential mechanism. In this paper, mechanism improvement of the rear unit to maintain the posture of the robot and constraint of the body length in the T-branches caused by this improvement are discussed, that is, installation of the additional passive wheels of the rear unit and its rectangle model in the T-branch. Finally, to verify the effect of this improvement and its mobility, experiments are conducted.
