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Design, fabrication, and characterization of in-pipe robot with controllable magnetic force

Pipes are everywhere, which should be inspected and maintained to ensure their safety and integrity. Although the in-pipe mobile robot is attractive for such application, the adhesion mechanism may be an obstacle. Thus, this paper presents the design, fabrication, and characterization of an in-pipe robot, which is capable of the controlled magnetic forces between the wheel and interior surfaces of ferromagnetic pipes at will. The first requirement is that the robot must fit into the ferromagnetic pipe with a diameter of 105 mm. The overall size of the robot is determined, based on the worst case with a 90° bend pipe. Then, the detailed design procedure is described including motor selection and related gear train design. The robot is designed into two symmetric bodies, fabricated, and assembled with sensors. A separate controller is designed and used for the tests. The second requirement is that the robot must run at a velocity of 1 cm/s with the capability of controlled magnetic force at will. The fabricated robot is subjected to test the requirements. The designed robot has the final dimensions with a length of 110 mm, and with a width of 100 mm. It satisfies the first requirement. The measured velocity of the robot is estimated as 1.2 cm/s with the capability of controlled magnetic force according to the slope of the pipe. It satisfies the second requirement.