Development of Internal Gas Pipe Inspection Robot

This paper describes a new mechanism and communication system for an in-pipe inspection robot. To date, inspection robots have been limited as to their mobility to turn in a T -shaped pipe or move in a plug valve. The new mechanism based on our dual magnetic wheels overcomes these limitations without difficult controls. This dual mechanism, resembling a crawler, enable the robot to climb over steep obstacles like sleeves and dresser joints. Another drawback of earlier robots is that the friction between the pipes and the cables for communication and power supply makes it difficult for them to move long distances. A fiber-optic communication system can reduce such friction. The spools of the fiber-optic communication cables and batteries are mounted on the robot and the cables are rolled or unrolled when the robot is moving forward or backward, respectively. An experimental inspection robot has been made to confirm the efficiency of the new mechanism. However, the robot fell off a Tshaped pipe when it attempted to turn in the pipe with its position being inadequate. It is difficult to eliminate such inadequacy because the robot might be disturbed while attempting to avoid a plug or because of sensors functioning uncertainly. For that reason, a mechanism which makes a robot twist is adopted. The improved experimental robot successfully turned in a T-shaped pipe even when its position was inadequate.