A Study of an In-pipe Mobile Robot Driven by Pneumatic Pressures Modeled on a Green Caterpillar

摘要

This paper describes the development of an in-pipe mobile robot driven by pneumatic pressure. In recent decades, natural gas has come to be supplied to most residences through polyethylene pipes laid under the roadways. As a result, it is necessary to inspect these pipes regularly to check for gas leaks caused by earth loads and oscillations resulting from vehicles traveling on the roads. Herein, we discuss a prototype pipeline inspection robot fabricated based on the model of a green caterpillar. In nature, caterpillars move forward on stems and leaves by the undulating motion of somites, and cling to leaves using abdominal legs and an anal proleg. Our robot is structured in the form of three somites and four suction brakes. Each somite, which contains four pneumatic bellows actuators, plays the role of a caterpillar somite, and suction brakes play the role of abdominal and an anal proleg. We confirmed that the robot is capable of moving at a speed of 9.7 mm/s inside an acrylic pipe more 34 mm in inner diameter, and can produce a maximum traction force of 4.2 N. In addition, the moving speed mechanism is clarified by using a model of the robot.