Underground Robots for Sewer Inspection

February 2015

Image Source: Redzone

The city of Barcelona has been selected to develop a pilot project for the robotic inspection of underground drainage and sewerage systems, as part of the innovation program of the European Union ECHORD++. This project, which began in 2014 and will end in 2018, is a response to a challenge that every urban settlement in the world has to face.


  • Integrating Robotics in Everyday Life - The ECHORD++ consortium (European Clearing House for Open Robotics Development Plus Plus), an integral part of the FP7 program of the European Union, aims to provide up-to-date technology to enable businesses and public administrations to integrate robotics into the daily life of the city over the next few years.

  • Public Bodies as Innovation Drivers - Because the city as such is the objective of the program, ECHORD++ involves public bodies in the development of robotic solutions by having them act as the principal buyers. By this means the public administration promotes innovation through its demand for these services and thereby helps in the transfer of robotic technology from the research laboratory to the market.

  • Barcelona’s Sewer System - The earliest Barcelona sewer system dates back to the ancient Roman settlement of Barcino, and some of the sections remaining from that time are still in use today. The current network has over 1,500 kilometers of tunnels and pipework, equivalent to the distance between Barcelona and Berlin. Only 50% of this infrastructure is accessible for inspection by traditional methods.


  • A Task that Meets the “3 d’s," for Being Dirty, Dangerous and Dull – Up until now the work of inspection of drainage and sewerage in cities has been done, for the most part, by human operators using manual systems. To do this these professionals must make their way into confined spaces, with all the associated risks, and then do their work in an environment where high temperatures, humidity and the presence of gases make any activity at all extremely difficult, uncomfortable, and even dangerous. This, together with the fact that many sections of sewer are not accessible to human beings, make this a field which is particularly suited to the use of robots.

  • Optimizing the Use of Public Resources - Maintaining the sewer system in good order which is not a danger to public health is a vital need for any city which wishes to prevent problems which can lead to disasters such as floods, subsidence, landslides, contamination of drinking water or environmental pollution. In the city of Barcelona sewer inspection runs to €1 million per annum in staff costs alone, a 12.5% ​​of the overall cost of managing and maintaining the system. The use of robotic technology will reduce these inspection costs by some 30%: from €0.75 per linear meter to €0.50 per linear meter. More accurate and efficient inspection will also allow better preventive maintenance and thus reduce the costs of cleaning, restoration and reconstruction, which together currently represent about 80% of the global cost of maintaining the network.

  • Towards more Versatile and “Smart” Autonomous Vehicles - In the current market there already exist tele-operated vehicles and autonomous robots to assist technicians in the inspection of sewers. The first generation of these consists of traditional vehicles which can be remotely controlled. They may have ultrasonic sensors, electromagnetic lasers and cameras with pan-tilt-zoom capabilities for the evaluation of structural problems and the recording of images and video from which 3D models can be generated. These images are collected by closed circuit television, and the displacement of the vehicle is limited by the length of the cable feed and control system. A second generation of such devices has spawned entirely autonomous robots. These overcome the limitations of cable since they can be introduced at one entrance to the sewer system and collected at a different one. They can incorporate the most advanced navigation technology, 360° imaging, 3D scanners and detectors of corrosive agents such as hydrogen sulphide. Their further development will undoubtedly increase these robots’ capacity for autonomous movement, their flexibility and freedom of manoeuvre within the sewers, as well as their ability to collect data more accurately. Beyond image and video, their data collection will extend to the sampling and analysis in situ of different components of the air, the waste water and its sediments.

  • Modular Robots on the Horizon - The characteristics of drainage and sewage networks can be very different in different urban settlements (the age of the infrastructure and the materials it is made from, variations in rainfall, temperature and humidity, the diameter and accessibility of the pipework, etc.), and even within the same town (the layout and alignment of the tunnels, differences in levels, presence of obstacles, etc.). Such very specific needs will lead to the design of specialized robots tailor-made for each job, but in environments where conditions are changeable, such customized designs can end up being very expensive. Robotics research is making advances in the use of new materials and structures which will allow robots to be adapted to a variety of circumstances without requiring new designs. An example of this is the Snake Monster of the Robotics Institute at Carnegie Mellon University, which is a robot made ​​of interconnecting modules which  can be easily re-configured for tasks as diverse as climbing trees, exploring pipelines or crawling over different types of terrain.