A V‐Shaped In‐Pipe Robot to Travel Through Complex Winding Pathways in Three Dimensions

ABSTRACT This paper presents a V‐shaped gas pipeline inspection robot which achieves high roll rotation performance, out‐of‐plane double elbow travel performance, and inverted siphon adaptability at high speed without requiring complicated manual operation. The principle for traveling through the out‐of‐plane double elbow was theoretically demonstrated and proven experimentally. The pitch angle of the robot's spiral motion, which is derived from the relationship between the roll angle of the spherical wheel and the angle of the V‐shaped joint, was also both theoretically and experimentally verified. Finally, field tests were conducted not only indoors but also outdoors on 8‐in steel pipes, and the robot successfully adapted to the out‐of‐plane double elbows, inverted siphons, and even buried pipes that were more than 20 years old. The robot even traveled up to 40 m without any problems, and returned safely after inspection and exploration.