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 Reporter May 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

People & Company News

Matson Completes Horizon Lines Acquisition

Matson, Inc. has completed the acquisition of Horizon Lines, Inc. which includes Horizon's Alaska operations and the assumption of all non-Hawaii business liabilities.

Wärtsilä Acquires L-3 MSI

Wärtsilä completes acquisition of L-3 Marine Systems International    Wärtsilä Corporation announced that its acquisition of the Germany based L-3 Marine Systems

BWTS Newcomer Sees Early Success

Norwegian manufacturer of ballast water treatment systems MMC Green Technology reports it has sold more than 70 systems since going commercial with its MMC BWMS two years ago,

Technology

Kongsberg Contracted to Support FLNG Conversion

Kongsberg Maritime secures position in the LNG market with electrical and automation contract for Golar Hilli FLNG   Keppel Shipyard in Singapore and Black & Veatch in the U.

New Power Optimization Solution for LNG Carriers

NAPA and DSME launch tailored NAPA-DSME Power Solution for LNG carriers; leading LNG carrier shipyard offers specialized performance monitoring solution   South Korean shipbuilder,

Design & Operation: Wind Farm Support Vessels

Offshore wind farm development has been led globally by the UK, followed by Germany. Both countries have governments with long term commitments to renewable energy.

Cruise Ship Trends

Overnight Cruise Ship Visits Suspended in White Bay

The New South Wales (NSW) Port Authority has suspended all overnight cruise ship visits to White Bay until the NSW Environment Protection Authority (EPA) has regulated

Star Clippers to Build Massive Square Rigger

Tall ship sailing specialist Star Clippers has announced that it has started building a fourth ship to add to its fleet of graceful square-riggers; its first new-build

Roxtec Sees Rise in Cruise Ship Repair Work

Manchester cable safety seal manufacturer Roxtec has reported increased demand for its cruise ship cable and pipe seals.   The firm has seen a 67 percent rise

Education/Training

Mass. Maritime Taps McDonald as New President

EVP Fran McDonald tops a field of five; choice still must be approved by Massachusetts Board of Higher Education.   Pending a confirmation vote by the Massachusetts Board of Higher Education (BHE),

SENER holds a FORAN seminar in Wuhan, China

The ‘FORAN new modules, new functions and FEM-Link (Hypermesh) Seminar’ was held on April 23rd in Wuhan. SENER is playing a big role in China, where it has been

New EU Shipping CO2 Monitoring System

According to a new EU regulation, ship operators will be required to monitor, report and verify (MRV) CO2 emissions.     José Inácio Faria, Member, Group of

Maritime Security

Thailand: 300 "boat people" Landed in Recent Weeks

Around 300 "boat people" have landed on Thailand's shores in recent weeks, Sek Wannamethee, director-general of the information department at Thailand's Foreign Ministry, said on Friday.

U.S.: China Placed Artillery on Reclaimed Island

The United States said on Friday that China had placed mobile artillery weapons systems on a reclaimed island in the disputed South China Sea, a development that Republican Sen.

Adm. Swift Takes Command of Pacific Fleet

Adm. Scott H. Swift returned to his home state and relieved Adm. Harry B. Harris Jr. as commander of the U.S. Pacific Fleet during a change of command ceremony on Joint Base Pearl Harbor-Hickam,

Marine Science

Lerwick Port Promoting Shetland Fishing Industry

The importance of investment in the Shetland fishing industry has been highlighted today by Lerwick Port Authority Chief Executive, Sandra Laurenson. The industry – white fish,

VIKING’s Top Safety Offerings at Nor-Shipping

Marine safety equipment leader VIKING Life-Saving Equipment will appear in force at Nor-Shipping 2015, displaying both innovative products and services that

US Forecaster Predicts Below-average Atlantic Hurricane Season

The Atlantic Ocean will see a below-average number of hurricanes this season due to cooler seas and a strong El Niño effect, the U.S. government weather forecaster announced on Wednesday.

Maritime Safety

Mass. Maritime Taps McDonald as New President

EVP Fran McDonald tops a field of five; choice still must be approved by Massachusetts Board of Higher Education.   Pending a confirmation vote by the Massachusetts Board of Higher Education (BHE),

Thailand: 300 "boat people" Landed in Recent Weeks

Around 300 "boat people" have landed on Thailand's shores in recent weeks, Sek Wannamethee, director-general of the information department at Thailand's Foreign Ministry, said on Friday.

U.S.: China Placed Artillery on Reclaimed Island

The United States said on Friday that China had placed mobile artillery weapons systems on a reclaimed island in the disputed South China Sea, a development that Republican Sen.

 
 
Maritime Security Maritime Standards Navigation Pod Propulsion Port Authority Ship Electronics Ship Repair Shipbuilding / Vessel Construction Sonar Winch
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: 0.2769 sec (4 req/sec)