GO WITH THE FLOW: MIT Invents Sensor Robot for Small Underground Pipes

by Carol Milano

3D model, Leak Detection Robot. Photo Courtesy of Mechatronics Research Lab, MIT

Dimitris Chatzigeorgiou (MIT Ph.D. candidate) left Athens for MIT in 2008, to pursue his Master’s degree (MS), and quickly discovered an exciting project his advisor was working on.  Kamal Youcef Toumi, professor of mechanical engineering, had been exploring the serious problem of freshwater loss with other engineers in the Persian Gulf, a constant concern in arid regions.  “Their international group came up with the idea of creating a robot to detect leaks in water pipes,” explains Chatzigeorgiou, who joined MIT’s new team for the project.  His group collaborates with engineers and students at King Fahd University of Petroleum and Minerals in Saudi Arabia (KFUPM), which sponsors and funds the project.  

No city in the world is free of water leaks reports Youcef Toumi.  “Some pipes may have leaks exceeding 40% of clean, processed water ready for consumer use!  With increasing populations, new technologies are important for generating clean water and distributing it efficiently,” he stresses.  Undetected, water or gas leaks beneath city streets can cause danger to both residents and properties.     

Chatzigeorgiou’s MS project involved identifying promising leak detection techniques for sensors.  “Old corrosive metal pipes are being replaced with cheaper, non-corrosive plastic.  No current approach has worked well enough in small plastic pipes.  Most detection systems are slow, inefficient, and costly.  They use above-ground acoustic sensors to listen for faint sounds or vibrations caused by leaks.”

Swimming module of the water pipe leak detection system, a palm-sized autonomous underwater vehicle that will be deployed in city water distribution networks. Photo Courtesy of Mechatronics Research Lab, MIT

The MIT-KFUPM leak-detection robot fits inside pipes as narrow as four inches in diameter.  It detects leaks of one to two millimeters in length, with higher speed and accuracy than other techniques, by sensing pressure changes.  “We discovered that our system for detecting leaks in water pipes also detects gas leaks,” says Chatzigeorgiou, now completing his PhD studies in Mechanical Engineering.  He worked mainly on the wheeled robot for gas pipelines and on optimizing the detection system.  You Wu, MS student in mechanical engineering, concentrated on a swimming robot for water pipes. 

“These autonomous robots move around, do inspections, and collect and report the data, all from inside the pipes,” notes Youcef Toumi.  “An intelligent machine doing maneuvers in complex pipe networks combines mechanical and electrical engineering skills.  The required motion planning and execution use different types of sensing to perform efficiently.  Mechanical engineers provide computational fluid dynamics; system modeling including electronics; the wireless communication systems; and control and estimation algorithms and their implementation.”  Instrumentation involves actuators, sensors, and an on-board computing platform that controls the robot and does detection

Developing the two prototypes, which work well at the lab level, "required 13 or 14 versions. The cost for the two prototypes was $1,000 in parts and production," reports Chatzigeorgiou. Several gas and water companies have visited the lab to see the robot and explore potential future collaboration. The technology needs further development and testing outside the lab. The next step is evaluating the prototype's effectiveness in a gas company's certified testing facility for leak detection. "We're optimistic about the results of these tests – I think the robot will generate a lot of industry attention. We hope to keep moving towards commercializing or licensing the technology." Several patents have already been issued; more are expected.

Chatzigeorgiou, lead author on articles published in four engineering journals, has visited KFUPM's team annually since 2010. At several international conferences about water systems, he's presented the leak detecting robot. "Everyone's excited about our technology, and that maybe our product can fill the current need."

Side view of a Carrier Prototype. Photo Courtesy of Mechatronics Research Lab, MIT

"Robotics is very exciting, and a bit unique," says Dr. Chris Jones, director of Strategic Technology Development at iRobot Corporation in Bedford, MA. "Mechanical, electrical and software engineers must work together throughout the product development process to elegantly solve engineering challenges. The best robot designers possess an in-depth knowledge in one engineering field, but have a working knowledge across all of them. It's important that an engineer has a good understanding of all the parts of a machine – artificial intelligence, sensors and action – and how they work together."

"Robotics has become an even more exciting area of research and development, integrating many disciplines, including mechanical engineering, controls, and instrumentation," agrees Youcef Toumi. "It's a great way for young engineers to learn and practice engineering! By applying your skills to problems that matter to people – whether it's aging infrastructure, self-driving cars, or robot helpers for the elderly –you can help provide real solutions for mankind."