Six-braided tube in-pipe locomotive device

Recently, many studies have been conducted on soft in-pipe robots, which are expected to work in pipes where ordinary rigid robots cannot work. In this paper, we present a new soft in-pipe locomotive device that consists of six braided tubes. The tubes of the device are inflated by pneumatic power whose inflation drives the device. This device can travel forward and backward and can rotate in both directions in pipes with various diameters with periodic pressurization of the six tubes. We have developed bundled-tube locomotive devices where each device consists of three tubes in which the devices can travel in pipes of various diameters without blocking the flow in the pipes. However these devices cannot control the their rotation in a pipe. Therefore, we developed the new bundled-tube locomotive device that can control the rotation in a pipe. This new device is a braid with six tubes that include a right-hand helix and a left-hand helix with three tubes each. The developed braided device can achieve various motions based on the pressurization patterns in each of the six tubes. In this paper, we thoroughly explain the relationship between the motions of the device and the pressurization pattern. We also present the locomotion experiment within a pipe with a variable-diameter part and a part that bends in an elbow shape.