In-Pipe Inspection Robot Capable of Actively Exerting Propulsive and Tractive Forces With Linear Antagonistic Mechanism

In this study, the authors comprehensively evaluated the traveling performance of a flexible pipe inspection robot (PI-RO) that can actively output both propulsion and traction forces. Household pipes must be frequently inspected for cracks and corrosion to ensure continuous provision of water and gas. As these pipes are essential for our everyday life, it is difficult to suspend their usage for long periods; hence, inspection should be conducted for short durations. In addition, inspecting entire pipelines using existing methods is challenging because the pipes are constructed over long distances and have complex structures. Therefore, we developed a flexible robot that can actively output propulsion and traction forces to inspect long-distance complex pipelines, such as household pipelines. Herein, we describe the flexible structural design of a PI-RO that inspects thin one-inch pipes (inner diameter of approximately 28 mm) typically present in household piping. We also evaluated the characteristics of each PI-RO unit. Finally, we confirmed that the PI-RO is not significantly affected by the traveling environment, such as long distances and complex small-diameter pipes, by conducting traveling experiments on small pipes (inner diameter 28 mm) and long-distance (up to approximately 11.7 m) complex pipes composed of horizontal, vertical, and 90° bend pipes.