Autonomous Robot Maps Ship Hulls for Mines

Jennifer Chu, MIT News Office
Wednesday, July 18, 2012
Algorithms developed by MIT researchers enable an autonomous underwater vehicle (AUV) to swim around and reconstruct a ship's propeller. Image: Franz Hover, Brendan Englot

Algorithms enable robot to navigate and view propellers and other complex structures.

For years, the U.S. Navy has employed human divers, equipped with sonar cameras, to search for underwater mines attached to ship hulls. The Navy has also trained dolphins and sea lions to search for bombs on and around vessels. While animals can cover a large area in a short amount of time, they are costly to train and care for, and don’t always perform as expected.
In the last few years, Navy scientists, along with research institutions around the world, have been engineering resilient robots for minesweeping and other risky underwater missions. The ultimate goal is to design completely autonomous robots that can navigate and map cloudy underwater environments — without any prior knowledge of those environments — and detect mines as small as an iPod.
Now Franz Hover, the Finmeccanica Career Development Associate Professor in the Department of Mechanical Engineering, and graduate student Brendan Englot have designed algorithms that vastly improve such robots’ navigation and feature-detecting capabilities. Using the group’s algorithms, the robot is able to swim around a ship’s hull and view complex structures such as propellers and shafts. The goal is to achieve a resolution fine enough to detect a 10-centimeter mine attached to the side of a ship.
“A mine this small may not sink the vessel or cause loss of life, but if it bends the shaft, or damages the bearing, you still have a big problem,” Hover says. “The ability to ensure that the bottom of the boat doesn’t have a mine attached to it is really critical to vessel security today.”
Hover and his colleagues have detailed their approach in a paper to appear in the International Journal of Robotics Research.

Seeing a shape in the dots
The engineering of such an inspection is a thorny computational problem that Hover and his group have investigated for the last decade. The researchers are coming up with algorithms to program a robot called the Hovering Autonomous Underwater Vehicle (HAUV), originally developed as part of MIT’s Sea Grant program. The technology has since been commercialized by spinoff Bluefin Robotics Corp., and the MIT engineers have continued to work to improve its performance through the years.
Fully viewing a massive structure such as a naval combat vessel — as well as all its small features, including bolts, struts and any small mines — is a tricky planning problem, according to Hover.
“It’s not enough to just view it from a safe distance,” Hover says. “The vehicle has to go in and fly through the propellers and the rudders, trying to sweep everything, usually with short-range sensors that have a limited field of view.”
The group approached the challenge in two stages. For the first stage, the researchers programmed the robot to approach the ship’s hull from a safe 10-meter distance, swimming in a square around the structure. The vehicle’s sonar camera emits signals that boomerang back as the robot makes its way around the ship; the researchers process the sonar signals into a grainy point cloud. At such a low resolution, Hover says one can clearly make out a ship’s large propeller, though not an iPod-sized mine.
“We get an immense point cloud,” Hover says. “And believe it or not, we see the shape of the ship’s structures emerge.”
However, Hover describes the point cloud as a “mist” that doesn’t necessarily tell a robot where a ship’s structures begin and end — crucial information for the robot to avoid colliding with a ship’s propellers. To translate this “mist” into a solid structure, the researchers adapted computer-graphics algorithms to their sonar data, generating a three-dimensional, “watertight” mesh model.

Up close and mine-able
For the second stage of their approach, the researchers programmed the robot to swim closer to the ship, navigating around the structure based on the mesh model. The idea, Hover says, is for the robot to cover every point in the mesh; in this case, each point is spaced 10 centimeters apart, narrow enough to detect a small mine.
One approach, he says, might be to have the robot sweep over the structure much like one would mow a lawn, one strip at a time — a common technique in robotic inspection. But such rectangular surveys can be tedious and time-consuming. Instead, the researchers came up with a more efficient approach, using optimization algorithms to program the robot to sweep across the structures while taking into account their complicated 3-D shapes.
The group’s technique significantly shortens the path a robot needs to follow to view an entire ship. “Over a minute or two of computation, we’re able to make tremendous improvements to the length of this path, and do so while keeping every single point in view,” Englot says.
Gaurav Sukhatme, a professor of computer science at the University of Southern California who was not involved in this work, sees the group’s work as an integrated approach to multiple problems, including “the extraordinary amount of data the vehicle has to intelligently process, and the safety considerations when operating near a hull that is being imaged or examined. I think a big application is going to be in servicing existing underwater rigs, and in decommissioning rigs no longer slated for use,” Sukhatme says.
The team has tested its algorithms in the field, creating underwater models of two vessels: the Curtiss, a 183-meter military support ship in San Diego, and the Seneca, an 82-meter cutter in Boston. The group is performing tests this month in Boston Harbor.
“The goal is to be competitive with divers in speed and efficiency, covering every square inch of a ship,” Englot says. “We think we’re close.”
This research is supported by the Office of Naval Research.

(Source: MIT:  http://web.mit.edu/newsoffice/2012/autonomous-robot-maps-ship-hulls-for-mines-0717.html)

Maritime Today


The Maritime Industry's original and most viewed E-News Service

Maritime Reporter June 2016 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

People & Company News

Norwegian Unions Say 755 O&G Workers Could Strike

About 755 Norwegian workers on seven oil and gas fields could go on strike from Saturday, hitting output from western Europe's top producer, if a new wage deal is not agreed before a Friday deadline,

Day of Seafarer: ICS Highlights Seafarers Role in Migrant Rescues

Gerardo Borromeo, Vice Chairman of the International Chamber of Shipping (ICS) took the opportunity today to highlight the courage that is currently being displayed by seafarers,

“Twiggy” Baker Wins BWT Puerto Escondido Challenge

Grant “Twiggy” Baker (ZAF) claimed victory today at the Puerto Escondido Challenge, besting a field of 24 of the world’s best big wave surfers in towering 20-to-35

Technology

Cathelco Supply BWT System for Cable Laying Vessel

Cathelco have supplied a ballast water treatment (BWT) system for the C.C. Pacifique, a steel barge which is being converted into a cable laying vessel for Coastal Carriers BV of the Netherlands.

Denmark Adopts Digital Ship Certification

As of June 24, 2016, ships flying the Danish flag are being digitally certified, making Denmark one of the first countries to put an end to the 100-year-old tradition

Prince Charles Places Final Section of UK Aircraft Carrier

The second of the largest warships ever built for the U.K. Royal Navy, the Queen Elizabeth Class carrier HMS Prince of Wales, was given the royal seal of approval when HRH The Prince of Wales,

Cruise Ship Trends

Ovation Of The Seas Sets Sail From China

Royal Caribbean christened their third Quantum class cruise ship, Ovation of the Seas, to huge fanfare in a ceremony in Tianjin, China.   The event marked the

Crystal Cruises Plans Return to Port Everglades

Crystal Cruises' ships will return to Broward County's Port Everglades beginning in Fall 2017, having last sailed from the port in 2006.   Beginning October 27,

Kiel is First German Port of Call for Mein Schiff 5

The brand-new TUI Cruises newbuilding Mein Schiff 5 has arrived in Kiel – her first German port of call since being handed over in Turku, Finland, a few days ago.

Education/Training

Danelec Launches ECDIS Computer-based Training

Danelec Launches ECDIS Computer-based Training   Danelec Marine has launched a new computer-based training (CBT) program for its second-generation DM800 ECDIS G2 products.

Antwerp Port Extends Partnership with DMU of China

The port of Antwerp is to collaborate with Dalian Maritime University (DMU) in northern China for the next three academic years. DMU is a prestigious Chinese maritime

Day of the Seafarer: Ban Spotlights Sustainable Agenda Targets

Marking the Day of the Seafarer, United Nations Secretary-General Ban Ki-moon highlighted the role of the shipping industry in moving forward the international

Maritime Security

Red River Closed after Barge Grounding

The Red River was closed Sunday from mile marker 40 to mile marker 42, after a barge reportedly ran aground and was protruding into the channel near mile marker 41, according to the U.

Chemical Tanker Runs Aground off Alaska

A 599-foot Norway flagged chemical tanker Champion Ebony ran aground near Nunivak Island, Alaska on June 24.   U.S. Coast Guard Sector Anchorage watchstanders

HMS Ambush Docks in Gibraltar

Navy nuclear submarine HMS Ambush yesterday steamed to Gibraltar – in a massive show of force against Spain.   The Spanish – emboldened by Britain’s Brexit vote

Marine Science

UK First to Accept Marine Geoengineering Amendments

The United Kingdom has become the first State to formally accept the 2013 marine geoengineering amendments to the 1996 “London Protocol”, the treaty covering dumping of wastes at sea.

Seven Indonesian Sailors Kidnapped in Philippines

Seven Indonesian sailors have been taken hostage in the Sulu Sea in the southern Philippines, Indonesia's foreign minister said on Friday, the latest in a string

Admiral of the Ocean Sea Award Recipients Named

The United Seamen's Service (USS) 2016 Admiral of the Ocean Sea Awards (AOTOS) will be presented to Arthur E. Imperatore, Founder and President of New York Waterways; Donald Marcus,

Maritime Safety

Tanker Crewman Medevaced off Virginia

The U.S. Coast Guard medevaced an ailing crew member Saturday from a tanker off Virginia Beach.   Coast Guard watchstanders at the 5th District Command Center

Day of Seafarer: ICS Highlights Seafarers Role in Migrant Rescues

Gerardo Borromeo, Vice Chairman of the International Chamber of Shipping (ICS) took the opportunity today to highlight the courage that is currently being displayed by seafarers,

USCG Investigates Unknown sheen in Lake Ontario

The Coast Guard is responding to a report of a sheen in Lake Ontario near the Fitzpatrick Nuclear Power Plant in Scriba, New York, approximately 10 miles northeast of Oswego, New York, Sunday.

 
 
Maritime Careers / Shipboard Positions Maritime Security Maritime Standards Naval Architecture Navigation Offshore Oil Pipelines Pod Propulsion Port Authority Shipbuilding / Vessel Construction
rss | archive | history | articles | privacy | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1448 sec (7 req/sec)