Nav: Home

Fiber-optic vibration sensors could prevent train accidents

July 17, 2019

WASHINGTON -- Researchers have developed new sensors for measuring acceleration and vibration on trains. The technology could be integrated with artificial intelligence to prevent railway accidents and catastrophic train derailments.

"Each year, train accidents lead to severe injuries and even deaths," said research team leader Hwa-yaw Tam, from The Hong Kong Polytechnic University. "Our fiber accelerometers could be used for real-time monitoring of defects in the railway track or the train to pinpoint problems before an accident occurs."

The researchers describe their new accelerometers in The Optical Society (OSA) journal Optics Express. The devices can detect frequencies more than double that of traditional fiber-optic accelerometers, making them suitable for monitoring wheel-rail interactions. The durable sensors include no moving parts and work well in the noisy and high-voltage environments found in railway applications.

"In addition to railway monitoring, these new accelerometers can be utilized in other vibration monitoring applications, for example, structural health monitoring for buildings and bridges and vibration measurements of aircraft wings," said Zhengyong Liu.

All-optical railway sensing

For more than 15 years, the researchers have been working on condition-monitoring systems that use an all-optical sensing network to continuously monitor critical railway components. These systems can help replace inefficient and costly scheduled railway maintenance routines with predictive maintenance based on actual conditions. Systems developed by the researchers have been installed in Hong Kong and Singapore.

"An all-optical sensing network has many advantages as it is immune to electromagnetic interference, has long transmission distance and the sensors don't require electricity," said Liu. "However, there is a need for fiber-optic sensors that are optimized to measure different parameters in railway systems."

The fiber-optic accelerometers typically used in condition-monitoring systems are based on fiber Bragg gratings (FBGs) and cannot be used to detect vibrations higher than 500 Hz. Although this is adequate for most railway applications it can't be used to measure the wheel-rail interactions that are an important source of track wear.

To overcome this problem, the researchers designed a new fiber-optic accelerometer that uses a special optical fiber known as a polarization-maintaining photonic crystal fiber that is coiled into the shape of a disc only 15 millimeters in diameter. The coiled fiber is glued between a stainless-steel substrate and a cylindrical mass block. When a vibration occurs, the mass block will press on the coiled fiber at a frequency matching that of the vibration. This external force causes the wavelength of light in the fiber to shift in a measurable way.

"This interferometric configuration uses changes in the light inside the fiber to acquire precise information about the vibrations," said Liu. "Installing these accelerometers on the undercarriage of an in-service train allows them to monitor vibrations that would indicate defects in the track. They can also be used to detect problems in overhead lines used to power trains."

Comparison field tests

After thoroughly testing prototypes of the new accelerometer in the laboratory, the researchers carried out a field test by installing the device on an in-service train. They also installed an FBG-based accelerometer and a piezoelectric accelerometer for comparison.

They found that the new fiber accelerometer detected acceleration in a manner similar to the piezoelectric accelerometer. However, piezoelectric sensors require expensive shielded cables to reduce the effects of electromagnetic interference noise. Because the FBG-based accelerometer can't operate well at high frequencies, noise concealed some of the useful vibration information.

"Our results showed that our new accelerometers perform considerably better than existing accelerometers used for monitoring acceleration in trains," Liu said.

In this work, the researchers used a commercial polarization-maintaining photonic crystal fiber. They have since designed and fabricated a new type of fiber with smaller outer diameters, lower bending losses and higher birefringence, all of which would allow them to build a smaller accelerometer with even higher sensitivity.

"These new accelerometers could open new sensing and monitoring possibilities by providing data that supports implementation of artificial intelligence in the railways industry," said Tam. "Although railway monitoring is a good example of how fiber-optic sensing can be combined with artificial intelligence, we believe this combination is also promising for a number of other industries and applications."
-end-
Paper: Z Liu, L. Htein, D. S. Gunawardena, W.-H. Chung, C. Lu, K.-K. Lee, H.-Y. Tam, "Novel accelerometer realized by a polarization-maintaining photonic crystal fiber for railway monitoring applications," Opt. Express, 27, 15, 21597-21607 (2019).

DOI: https://doi.org/10.1364/OE.27.021597.

About Optics Express

Optics Express reports on new developments in all fields of optical science and technology every two weeks. The journal provides rapid publication of original, peer-reviewed papers. It is published by The Optical Society and edited by James Leger from the University of Minnesota. Optics Express is an open-access journal and is available at no cost to readers online at: OSA Publishing.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.

Media Contact: mediarelations@osa.org

The Optical Society

Related Artificial Intelligence Articles:

Researchers rebuild the bridge between neuroscience and artificial intelligence
In an article in the journal Scientific Reports, researchers reveal that they have successfully rebuilt the bridge between experimental neuroscience and advanced artificial intelligence learning algorithms.
Artificial intelligence can help some businesses but may not work for others
The temptation for businesses to use artificial intelligence and other technology to improve performance, drive down labor costs, and better the bottom line is understandable.
Artificial intelligence could help predict future diabetes cases
A type of artificial intelligence called machine learning can help predict which patients will develop diabetes, according to an ENDO 2020 abstract that will be published in a special supplemental section of the Journal of the Endocrine Society.
Artificial intelligence for very young brains
Montreal's CHU Sainte-Justine children's hospital and the ÉTS engineering school pool their expertise to develop an innovative new technology for the segmentation of neonatal brain images.
Putting artificial intelligence to work in the lab
An Australian-German collaboration has demonstrated fully-autonomous SPM operation, applying artificial intelligence and deep learning to remove the need for constant human supervision.
Composing new proteins with artificial intelligence
Scientists have long studied how to improve proteins or design new ones.
Artificial intelligence and family medicine: Better together
Researcher at the University of Houston are encouraging family medicine physicians to actively engage in the development and evolution of artificial intelligence to open new horizons that make AI more effective, equitable and pervasive.
Artificial Intelligence to improve the precision of mammograms
The Artificial Intelligence techniques, used in combination with evaluations by expert radiologists, improve the precision in the detection of cancer through mammograms.
Using artificial intelligence to assess ulcerative colitis
Researchers from Tokyo Medical and Dental University (TMDU) have developed an artificial intelligence system with a deep neural network that can effectively evaluate endoscopic data from patients with ulcerative colitis, which is a type of inflammatory bowel disease, without the need for biopsy collection.
Robot uses artificial intelligence and imaging to draw blood
Rutgers engineers have created a tabletop device that combines a robot, artificial intelligence and near-infrared and ultrasound imaging to draw blood or insert catheters to deliver fluids and drugs.
More Artificial Intelligence News and Artificial Intelligence Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.