Business / Tech

Mitsubishi Heavy unveils robot for use when flammable gas has leaked

by Shusuke Murai

Staff Writer

Mitsubishi Heavy Industries Ltd. on Tuesday unveiled a robot that can operate in the presence of flammable gases, such as after a gas leak following a disaster.

A joint project with Chiba Institute of Technology, the Sakura No. 2 is the country’s first mobile inspection unit that can operate in the presence of high concentrations of explosive gases such as methane and hydrogen.

There is an increasing need for an inspection robot that is not a fire hazard as Japan steers toward becoming a hydrogen-based society, said Ken Onishi, a senior engineer in charge of the project for Mitsubishi Heavy.

“There was a debate over whether to develop robots that can operate near hydrogen gas, as doing so requires an extremely high level of technology,” Onishi said. “As we may encounter accidents such as collisions involving hydrogen cars or a truck loaded with hydrogen tanks rolling over inside a road tunnel, we decided to develop a robot that can deal with such situations.”

Equipped with cameras, caterpillar tread belts and an antenna for radio remote control, the robot can enter a site immediately after an accident — something humans often cannot do until flammable gases dissipate. The robot also has a kilometer-long optical fiber cable to allow control in case its radio-based control fails.

Components that could cause heat or sparks, such as lithium ion batteries and motors, are covered by a special pressure-resistant container, ensuring that flammable gases do not come in contact with electronics systems. The unit can operate for up to 2.5 hours using its battery.

The development of the disaster-response robot was a result of the lessons learned from fatal accidents inside road tunnels in recent years, Onishi said.

In December 2012, when a ceiling collapsed inside the Sasago tunnel on a highway in Yamanashi Prefecture, killing 9 motorists, rescuers could not immediately reach the crushed vehicles because of flammable fumes from spilled gasoline.

Onishi said there may be a market demand for about 3,000 of the robots.

A robot developed by Chiba Institute of Technology, called Quince, has been used at Fukushima No. 1 nuclear power plant to shoot video inside the highly contaminated buildings, where humans cannot work.

“As much of the social and industrial infrastructure built during the period of fast economic growth, such as oil refineries, chemical plants and electricity plants, gets older … there has been an increasing need for robots that can probe about and perform light duties,” he said.

The project is funded by the state-backed New Energy and Industrial Technology Development Organization (NEDO).

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