Tunnel inspection: Kyoto University and MinebeaMitsumi to test an innovative technology

In Japan, about 34% of existing tunnels will pass 50 years since construction by 2023, so demand for tunnel inspection services is rapidly increasing to allow rapid intervention in case of need, while enabling economically efficient predictive maintenance. In addition to conventional methods employing skilled workers, image processing technology, such as cameras and radars, and sensor-based solutions are being used for data-driven, highly reliable and advanced tunnel inspection and infrastructure maintenance.

Kyoto University has been researching an innovative technique leveraging microwave wireless power supply technology for many years. Although technological development is complete, this method proved to have some convenience and practical problems, so it was difficult to implement. With the cooperation of Kyoto Prefecture, Kyoto University received a license from the Kinki Bureau of Telecommunications using the National Strategic Special Zone System, to conduct a new social demonstration experiment at the Jizo Tunnel evacuation tunnel in Miyazu City, Kyoto Prefecture.

In this experiment, which is expected to take place from October 19th to 24th, 2020, a recursive-type infrastructure monitoring system will be used to monitor the falling or collapse of heavy ancillary equipment such as jet fans for smoke exhaust that are bolted to tunnel structure frames. This system is used in the Kyoto University COI program and mainly developed by our parent company MinebeaMitsumi, proving a combination of technologies for microwave wireless power transmission, high-speed image signal processing and battery-less bolt axial force sensors.

The solution will be able to collect sensing information in real time while transmitting power from a traveling vehicle to a sensor. Main goal is to demonstrate the validity of the entire system and the accuracy of data obtained by road-to-vehicle communication, while confirming the possibility to efficiently and economically run tunnel inspection without imposing any traffic restriction.

By putting Kyoto University’s world-leading technology into practical use, the convenience and potential of microwave wireless power transmission could be widely applied to tunnel inspection as well as to the monitoring of bridges, paved roads, sewer pipes, slopes, etc., both in Japan and other countries facing the issue of ageing infrastructure.

Read more about the social demonstration test at Takiba Jizo Tunnel on MinebeaMitsumi’s website

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