Pneumatic robot based on inchworm motion for small diameter pipe inspection

By using only one pneumatic line, an inchworm like micro robot for pipe inspection is invented. This paper is based on drilling different-sized micro holes in two plates among three chambers. The rear clamp, the elongation module, and the front clamp work sequentially as the air flows to each chamber. It enables the robot not only to generate inchworm like locomotion, but also to allow significant reduction of the stiffness of pneumatic lines and the drag force due to one pneumatic line. In addition, a micro robot with diameter of 10 mm could be accomplished owing to its simple structure of chambers. In order to operate the robot efficiently, the stroke according to the supplied pneumatic pressure is investigated. Based on the result, maximum theoretical velocity is obtained by tuning the air insufflation time under in-pipe condition. Finally, the adoptability of the robot is tested under variation of pipe diameter.