Sensors and crabbing for an in-pipe magnetic-wheeled robot

Abstract

Summary form only given. This paper describes an adhesion status detection sensor as well as crabbing for an in-pipe magnetic-wheeled robot. The robot targeted in this study can travel in any position within a pipe via magnetic-wheel adhesion, and can easily negotiate bends in pipe elbows and T-pieces. Moreover, the dual structure of the wheels ensures superior travel performance even over gaps like those commonly found in gas and other pipelines. However with no sensor in the robot for accurately judging its own adhesion status, we had a significant problem because the robot had to be attached to the pipe in order to travel. Steps also had to be taken because it looked like the adhesion status of the robot might well deteriorate under certain conditions, such as when traveling over weld lines or when reacting to avoid obstacles. To that end, we used a Hall element to accurately detect adhesion status, and then set about confirming the efficacy of the element using an actual robot. We found with the Hall element output that inner magnetic-wheel rotation generated periodic vibration, so we eliminated this vibration as well. We also propose a new means of travel related to crabbing, which is the magnetic car-type robot's unique motion for mobility, and we set about confirming the efficacy of this means of travel using an actual robot.