Inspection- and repair robots for waste water pipes a challenge to sensorics and locomotion

Sewerage is a very large and important infrastructure in the water industry. Because around 20% of the municipal pipe network is estimated to be significantly damaged, it is of high priority to inspect, maintain and repair public sewers. During recent years mobile robots have been developed to inspect but also to repair the pipes. To navigate through the hostile environment, they are generally only equipped with video cameras and connected to the outside world via an umbilical cord which transmits the image information. The tethered robots are tele-operated from a remote service station placed at the end of a maintenance shaft. These pipe robots are commonly wheeled systems especially adapted to withstand the adverse conditions of the waste pipe environment. In this paper the actual state of the art in the field of mobile robots for repair and inspection of sewerage is given and the possible improvements of the next generation of robots caused by developments of the sensors, the material, the tele-operation techniques and the locomotion principles are reported. This will allow the robots to increase their capabilities and to enlarge the application areas to pipes with smaller diameters and pipes in industrial plants