A Small In-Pipe Inspection Robot with Integrated Holding Force Mechanism

An inspection inside narrow-diameter pipes is one of the most challenging tasks in robot-assisted inspections. To navigate pipe systems, the robot must overcome difficulties, such as wet conditions, corners-and-curves, and pipe-diameter differences, but the smaller pipelines make such tasks more difficult. In this paper, we present a novel pipeline robot with a high environmental adaptability that can fit in pipe diameters from 12 to 25 mm. The robot consists of 2 links connected together by an active joint which allows the robot to extend and flex. Such a mechanism enables the change of its height and exerts a force against the upper walls for holding the robot inside the pipes. Two locomotion modes are presented, and the functionality of the integrated holding force mechanism is validated. Finally, the performance of the robot is confirmed throughout experiments, and the resulting robot smoothly and steadily moves through complex pipe configurations, including vertical and bent pipes.