A team of American roboticists from the Center for Robot-Assisted Search and Rescue wrapped up five days of underwater search and rescue operations in northern Japan on Saturday.
During five days of work in two of the most badly damaged cities in northern Japan, they deployed three underwater remotely operated vehicles to check for victims and debris following the March 11 tsunami.
Six weeks from the disaster, more than 14,000 people are confirmed dead, and 12,000 remain unaccounted for. Some of the missing are believed to have been swept out to sea, and the robots were called in to search in areas judged too dangerous for Japan Coast Guard divers to enter.
"In particular, trapped under floating debris or washed up in dangerous places," said Robin Murphy, director of the Center for Robot-Assisted Search and Rescue (CRASAR), which is based at Texas A&M University. Murphy led the team of five roboticists in Japan and was speaking at a news conference on Sunday.
A SARbot from San Diego-based Seabotix was employed to search under debris. (Video of the robots and what they encountered underwater is available in this YouTube video.)
The robot can literally be thrown in the water and gets to work immediately.
Equipped with a sonar system, video camera, and powerful lights, the remotely operated vehicle (ROV) connects via cable to a suitcase-size control system. The case includes a 20-inch display and Core2 Duo-based computer system, and a controller pad with a joystick for maneuvering the vehicle.
At one point it was sent to investigate the roof of a house, which was floating at sea.
"We were able to fly underneath the roof and all the debris and look up to see if there was anything that was trapped inside the roof space," said operator Jesse Rodocker, from SeaBotix.
Rodocker also showed video of a submerged car. The ROV was able to confirm there were no victims inside and determine the vehicle's license plate number. In some cases, it was also able to retrieve items from underwater. It has a grabber arm that can lift items weighing up to 100 kilograms (220.46 pounds).
A second device used to check debris was the AC-ROV, a Scottish-made remotely operated vehicle described as "basically a video camera with thrusters."
During the five-day mission, the ROVs didn't find any victims. It's now assumed that any bodies remaining in the water are probably tangled up in debris out of sight and reach of both divers and robots.
The second focus was scanning the seabed to locate any large pieces of debris that remained underwater and out of view. Large pieces of debris could endanger ships, so checking beneath the surface is a vital step toward reopening ports.
In Minamisanriku, a Seamor ROV with sonar was tasked with just that job. To the team's surprise, they didn't find a lot of debris on the seabed and almost everything located was not a danger to ships.
"All the fishing nets, all the ropes were at least 5 meters deep, except for one structure that was clearly visible above the water line," said Murphy.
The mission is the latest in a series of deployments for CRASAR. The center was responsible for the first use of ground robots at the World Trade Center site in New York shortly after the September 2001 terrorist attacks. The group also deployed small air vehicles after Hurricane Katrina and underwater ROVs after Hurricane Wilma.
The team that's been in Japan was funded by the U.S. National Science Foundation.