How a military of sewage robots will help us repair our clogged pipes

There are about a million kilometers of pipes beneath Britain’s streets, buildings and parks. The maintenance and repair of these pipes requires around 1.5 million road excavations per year, resulting in total or partial road closures. These jobs are noisy, dirty, and cause a lot of inconvenience. They also cost around £ 5.5 billion a year.

It doesn’t have to be like that. Research teams like me are working to save the time and money on pipe maintenance by developing infrastructure robots.

In the future, these robots will work for us to repair our roads, inspect our water and sewer pipes, maintain our lampposts, monitor our bridges, and maintain other vital infrastructure. They can get into places that are difficult or dangerous for people, such as sewer pipes full of harmful gases.

We develop small robots for underground pipe networks, both in clean water and in sewers. They inspect them for leaks and blockages, map where the pipes are, and monitor their condition for signs of problems. But what if the robots have to go to places where our existing wireless communication can’t reach them? If we can’t communicate with them, we can’t be in control.

Pipebots swim around the network of sewage and clean water pipes. Human Studio, author provided

The pipe bots

The underground pipe networks are complex, varied and difficult to work with. There are many sizes of pipes made of different materials and arranged at many different depths. They are connected in many different configurations and filled with different content to different extents.

Pipebots is a large UK government funded project that is working on robots that will help maintain the piping system. These robots come in different sizes depending on the pipes. For example, the smallest must fit into a 2.5 cm (1 inch) side cube, while the largest are up to 50 cm long.

Thanks to the numerous sensors on board, they work autonomously. The robots use computer vision and a combination of an accelerometer, a gyroscope, and a magnetic field sensor to sense where they are. They have ultrasonic and infrared distance sensors to help them navigate the pipes. Finally, they will also have acoustic sensors and ultrasonic sensors to detect cracks in water pipes and blockages in sewer pipes and to measure the overall condition of those pipes.

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The information gathered in this way is sent to the water company responsible for the pipes. Primarily, the robots only monitor the pipes and call a separate repair team if necessary.

One of the biggest challenges will be that they communicate with each other through the pipes. This requires a wireless communication network that can function in a variety of conditions as the pipes may be empty, full of water or sewage, or somewhere in between. The three main options we are investigating are radio waves, sound waves, and light.

Diagram of how the robots monitor pipes.The robots have acoustic sensors and ultrasonic sensors to detect cracks in water pipes. Human Studio, author provided

Radio waves

Wireless communication technology using radio waves is ubiquitous these days – WLAN, Bluetooth and of course cellular networks such as 4G. Each of these works at a different frequency and has different bandwidths.

Unfortunately, none of these signals can pass through the ground. We’re all too familiar with how cell phones drop out when a train goes through a tunnel. However, if we already had a base station in the tunnel, radio waves could be transmitted along its length.

Fortunately, sewer pipes look very much like tunnels for radio waves – at least when they are relatively empty. We’re adapting technology similar to Wi-Fi and Bluetooth to make sure the Pipebots checking the sewer inspection are always connected to the control center.

Water blocks radio waves even more than soil and earth do. In fact, at sufficiently high frequencies it acts as a mirror. In order to keep control of the robots in our water pipes, we need to use both sound and light.

Computer generated image of the robots in a pipe.They have ultrasonic and infrared distance sensors to help them navigate the pipes. Human Studio, author provided

Sound and light

Wireless communication methods using sound and light are not yet widely used in commerce. But they are making waves in the research community.

One method, visible light communication (VLC), uses transmitters and receivers, such as B. LEDs that are small and small Energy efficientand also offer dazzling data rates on the order of ten gigabits per second. However, because the light moves in a straight line, VLC can only be used when robots that are close together need to communicate. One possible solution is to have many robots in the same pipe and form a chain along which information can be transmitted in pipe bends.

On the other hand, sound can travel for miles along pipes and move around corners with ease. The downside is speakers and microphones can be greedy for powerand sound does not offer particularly high data rates. Instead of the billions of bits per second that can be sent with 5G and post-5G technology, sound waves can only transmit a few bits per second. While this is enough to know if a particular robot is still working, it is not enough to relay a lot of useful information about the pipes.

In the video above, tThe first pipe robot in action.

It’s not about choosing radio, sound or light waves. The wireless communication network we are developing for our underground little helpers will use a combination of these methods. This ensures that the robots are doing what they are supposed to do, that we are in control of them, and that they keep their promises.

We hope that a full Pipebots system will be demonstrated in a realistic network by 2024. Once this is successful, we will need to go through a thorough certification and compliance process to ensure that Pipebots can be used safely on living water and sewer systems.The conversation

This article by Viktor Doychinov, a research fellow at the University of Leeds School of Electronic and Electrical Engineering, has been republished under the Creative Commons license by The Conversation. Read the original article.

Published on January 29, 2021 – 10:00 UTC

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