Localization of structural flaws in concrete sewer pipes by physical interaction inspection with a robotic arm

Under our streets and houses there exists a large network of sewer pipes. These sewer pipes need maintenance and eventually need to be replaced. Currently these pipes are visually inspected, where videos are recorded by CCTV enabled carts driving through the sewer pipe. This research studies the feasibility of inspection of the concrete sewer pipes by physically interact with the pipe. Where the research question is stated as follows: To what extend can interaction between a robotic arm and the surface of a concrete pipe be used to locate structural flaws of the pipe? The principle of a rebound hammer has been studied and its principle has been mimicked, in order to inspect the concrete with a robotic arm. The rebound coefficient, obtained by applying an impact on the surface with the end-effector of the robotic arm, contains information on the structural integrity of the sample. The proposed method has been evaluated in an experimental study and various variables have been investigated. Furthermore, the method has been tested in order to determine if structural flaws in concrete can be localized. The method has shown to be able to locate a void in concrete. A crack in concrete could not be located.