Locomotion with articulated legs in pipes or ducts

Abstract Different implementations of remote controlled robots exist that can inspect and repair the interior of a pipe or duct. For this purpose they have video cameras and tools like a welding set or a grinder on board. This paper describes an approach with articulated legs that are pushed against the walls to obtain a grip. In contrast to wheels, for instance, legs overcome problems of common pipe inspection robots, like branches or obstacles in the pipe. The robot has a hierarchical control architecture with reflexive behaviour in the lower layers. In a two-dimensional simulation environment the robot performed successfully in several shapes of pipes. The results show that simple reflexive behaviour is sufficient to overcome even complex shapes. In the tested environment, reflexive behaviour prevented deadlock and ensured the robot's safe operation.