National guidelines that show the functions necessary for the safe operation of unmanned aerial vehicles that move automatically underwater, which are also called "sea drones," have been compiled, and technological development is in full swing with a view to using them for commercial purposes.
An unmanned vehicle that automatically moves underwater without being operated by a person is called an "AUV" and is used for "research purposes" such as seafloor surveys in Japan.
According to the Ministry of Land, Infrastructure, Transport and Tourism, technological development has progressed, and it has entered the stage where it can be used for "commercial purposes", and it is expected to be used for maintenance such as offshore wind power generation, which is also planned to be introduced in Japan.
On the other hand, if a collision occurs, there is a concern that it will have a large impact, so the Ministry of Land, Infrastructure, Transport and Tourism has compiled guidelines that show the functions necessary for safe operation, and installed a system that accurately detects the surrounding situation and avoids obstacles. In addition to seeking, it is desirable not to fix avoidance in one direction in order to avoid secondary collisions.
The Maritime Safety Technology Research Institute, which leads the AUV technology at a national research institute, confirms that the AUV it owns meets the safety functions indicated in the guidelines, and then conducts demonstration experiments to move multiple aircraft in cooperation. Development is in full swing.
The government is also making efforts to support the development of private companies, and it is expected that the utilization of safe AUVs will be promoted domestically.
From "research purpose" to "commercial purpose"
The National Maritime Research Institute has installed AUVs on two survey vessels to investigate the topography of the seafloor, and the National Maritime Research Institute has been conducting seafloor calderas off the Izu Islands and lake bottom ruins of Lake Biwa since 2016. It is used for research and so on.
Last October, I took an AUV shot of the seabed where carbon dioxide bubbles are generated due to the effects of volcanic activity on Shikinejima in the Izu Islands.
This seabed was previously shot by divers, but the AUV can move at a constant height and speed, which means that it was the first time to accurately shoot a wide area.
Data on the acidity of seawater is also collected, and by comparing it with the video, it is possible to grasp changes in the marine environment.
AUVs are being used more widely from these "research purposes" to "commercial purposes."
Kawasaki Heavy Industries, a major machinery manufacturer, has developed the world's first AUV that inspects submarine pipelines with a robot arm, and received an order from a company that inspects underwater equipment in the United Kingdom.
A sensor is installed at the tip of the arm, which means that the pipeline of natural gas, etc. stretched in the deep sea can be inspected for a long time regardless of water pressure or tide flow.
Currently, pipelines are inspected by divers or submersibles that are remotely controlled from the mothership, but AUVs can work for up to eight hours and are expected to significantly reduce costs.
The three offshore wind turbines operating in Japan are also inspecting underwater equipment and transmission cables in the same way, and the country is aiming to introduce thousands of offshore wind turbines by 2040. Therefore, expectations are high for AUV technology development.
Aim to work on the seabed in cooperation with multiple "AUVs"
On the 7th of this month, the National Maritime Research Institute in Mitaka City, Tokyo, conducted a demonstration experiment in which two AUVs were operated in a 40-meter-long water tank to see if each could grasp the position information of the other party.
It has been confirmed that the two units meet the safety functions indicated by the national guidelines, and in the experiment, they were instructed to grasp the position information of the other while automatically going back and forth over a distance of 10 meters according to independent instructions. I did.
Since radio wave communication is difficult underwater, technology to grasp the position with a sound wave signal is required, and the two units proceeded while emitting a sound like a dolphin's bark from the installed equipment.
When the round trip was completed, the data was automatically sent to the computer that gave the instruction by rising to the surface of the water, and according to the person in charge, it was confirmed that the position was grasped almost accurately.
Grasping location information is considered to be the first step in collaborative technology, and once the technology is established, one operator will be able to operate multiple AUVs at the same time, and inspection of offshore wind power generation will be carried out in a shorter time. It means that you will be able to do it.
Masahiko Shinono, who focuses on development, said, "I expect that the risk can be significantly reduced by using AUVs in places where humans are diving and inspecting. Multiple AUVs cooperate. I want to aim to work on the seabed. "