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Roboboats could be wave of the future

In May 2013 Benjamin, a Wave Glider named after Benjamin Franklin, was awarded a Guinness World Record for the longest journey by an autonomous surface vessel. The 7-foot surfboard-shaped “roboboat” traveled 7,939 nautical miles from California to Australia powered by waves alone and guided by an on-board command-and-control computer. No skipper.

The Wave Glider comprises a floater with a solar panel tethered to a “wave engine” below that moves the vessel forward.

The Wave Glider, designed and built by Liquid Robotics of Sunnyvale, California, a Silicon Valley start-up founded in 2007, survived shark attacks, powerful currents and Tropical Cyclone Freda during the 15 months it was in transit, all the while collecting and transmitting wave, ocean and weather data.

The Wave Gilder pokes along at a top speed of just 3 knots and averages about 1.8, but like the Energizer Bunny it keeps going. It needs no fuel; its information-gathering sensors, an on-board computer and a satellite transceiver are solar-powered. It generates no pollution and can operate autonomously, its route preprogrammed on an on-board computer or by remote control with a “helmsman” in Sunnyvale guiding the Wave Glider from a computer console.

The Wave Glider converts wave motion to propulsion with its two-part architecture — a floater on top of the water tethered to a smaller “wave engine” below. The propulsion system relies on the difference between wave action at the surface and wave action at greater depths.

“If you’re a scuba diver, you know it can be very rough on the surface and quite calm below,” says Graham Hine, one of Liquid Robotics’ founders and its vice president for product management.

The wave engine has horizontal foils — much like airplane flaps — that flutter up and down as the floater rides the waves. When the float rides up a wave, pulling the propulsor up, the flaps flip up and push the Wave Glider forward. When the float rides down a wave, the propulsor sinks and the flaps flip down, again pushing the Wave Glider forward. Like a swimmer kicking with fins, the up-and-down motion of the foils powers the Wave Glider, even in tiny waves.

The floater’s deck is a solar panel that supplies the vessel’s electricity. The newest model, the SV3, has a 10-foot floater and a small electric-powered prop on the propulsor to give the Wave Glider a boost in powerful currents or doldrums.

Hine says the hybrid package is balanced to keep the Wave Glider moving in variable conditions — in the tropics, where there is a lot of sun but at times not many waves, and in higher latitudes, where there are a lot of waves but sometimes not much sun.

The Wave Glider — and other autonomous, wave-powered vessels like it under development in the United States, the United Kingdom and elsewhere — are poised to revolutionize the way scientists, researchers, businesses and governments collect data from the oceans. Hine likens this technology’s ability to probe the depths and breadth of the oceans to that of satellites that probe vast regions of space.

The record-setting Wave Glider Benjamin approaches Hawaii, collecting data as it pokes along.

“What this technology enables us to do is reach out much farther [and deeper] into the oceans with our eyes and ears and find out what’s happening out there,” he says.

In October 2014, seven autonomous, wave-powered vessels — four types from the United States and the U.K., including Wave Glider — gathered for a trial hosted by the U.K.’s National Oceanography Center. The event launched the roboboats on a weather and ocean data collection mission while navigating a 500-mile course in waters marking the boundary between the Atlantic and the English Channel.

Link to the undersea world

As more and more of these unmanned wave-powered vessels cruise and collect information, they can vastly improve our understanding of the oceans and increase the volume of data available for a host of purposes. Liquid Robotics says its Wave Gliders can be used to map the ocean floor, study plate tectonics, cruise drilling rigs looking for oil leaks, patrol harbors for suspicious vessels and swimmers, track whales, explore for offshore oil, investigate underwater volcanoes, monitor fish populations, watch for tsunamis, hunt submarines and enforce fisheries laws.

“It can link us to the undersea world in a way that is persistent and global,” Hine says.

Until now, crewed research boats or law-enforcement patrol boats have done most of this work. Hine says the Wave Gliders won’t necessarily replace those workhorses, but they can be a “force multiplier,” swarming the waters nearby and miles away from the “mother ship,” collecting information.

Liquid Robotics has a fleet of 260 Wave Gliders in service around the globe, most owned by the businesses, government agencies and universities that use them. In 2011, NOAA partnered with Liquid Robotics to deploy two Wave Gliders in the Arctic’s Beaufort Sea for 55 days in late summer, when the water was ice-free. The Wave Gliders covered 2,700 nautical miles and collected close to 900,000 surface water temperature readings that showed the Beaufort Sea was unusually warm.

One of the most unlikely missions that Hine recalls was the deployment of a Wave Glider by particle researchers to measure at sea the background radiation of the universe. NOAA has been using one in the Caribbean to study hurricane formation.

Although he does not see any direct use for Wave Gliders in boating — not yet, at least — he says boaters will benefit indirectly from the data collection through better weather forecasts, more real-time ocean weather and wave data, improved understanding of the behavior and health of fish species, more information about the health of the oceans, and better intelligence on terrorists and pirates at sea.

As autonomous data-collection vessels proliferate, they could become a hazard to navigation — an issue that Hine says Liquid Robotics is working on. “It is a challenge,” he says. “We don’t like to be run over.” The surface floaters are made of foam and fiberglass, so he does not see them as likely to hole a hull in a collision.

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He says the floaters are outfitted with lights and flags so they can be more easily spotted, and they carry an AIS receiver. That enables the Wave Glider’s computer to “see” vessels in its vicinity that are transmitting an AIS signal and take evasive action. The company also is working with the Coast Guard to develop rules for putting AIS transmitters on the Wave Gliders so other vessels can “see” them, and it is developing an acoustical detection system to enable the Gliders to “hear” approaching vessels. “We’ll try to dodge out of the way if we hear something coming toward us,” he says.

Liquid Robotics spokeswoman Joanne Masters puts the retail price of a Wave Glider at $225,000 to $300,000 for the basic platform. Users equip the platform with scientific gear at their own expense. “The cost is in the hundreds of thousands of dollars, not in the tens of thousands or millions,” Masters says.

Humpback origins

Autonomous, wave-powered roboboats are changing the way ocean data are collected.

The Wave Glider’s development is a story of one man’s passion germinating into an invention that has turned out to have applications far beyond its original purpose. As Hine tells the story, Silicon Valley venture capitalist Joseph Rizzi, who owns a beachfront home in Hawaii, wanted to stream the “songs” of humpback whales cavorting in nearby waters to the sound system in his house.

He started by using a kayak, a hydrophone, a pickle jar and a long cable to bring the whales’ songs to shore, but the gear kept getting swept away in storms because he couldn’t anchor it in marine sanctuary waters. So he asked friend and neighbor Derek Hine, an inventor and aerospace engineer, and Hine’s son Roger, a Stanford-educated robotics designer (who is also Graham Hine’s brother) to develop an “unmoored, station-keeping data buoy” to collect and transmit the whale songs to shore — live.

Using a large fish tank he bought on Craigs-list, Roger Hine developed the concept for the Wave Glider over several months. As Hine demonstrated his protoype in a backyard swimming pool to a group of men who had become interested in the project, they were amazed at the device’s ability to move about under the power of waves generated by pumping a cooler up and down in the pool — and to stay on station using a crude rudder.

The idea of the Wave Glider was born. “Recognizing the commercial potential for the technology, the group launched Liquid Robotics with Roger as the founding CEO in January 2007,” the company website says.

With wave-powered vessels becoming more sophisticated, autonomous operation is becoming more sophisticated, as well. Last fall, 15 teams entered autonomously controlled 16-foot catamarans in the first International Maritime RobotX Challenge in Singapore. Co-sponsored by the Office of Naval Research and the Association for Unmanned Vehicle Systems International Foundation, the competition focused on the hardware and software needed for the autonomous operation of roboboats.

Like the autonomously controlled cars that Detroit is working on, roboboats require neither a driver in the boat nor a remote operator. The catamarans had to operate on preprogrammed instructions and respond on their own to challenges.

The robotic boats were tasked with maneuvering along a marked course and passing through 10-meter-wide start and finish gates; undertaking an underwater search to locate a device emitting an acoustic signal; identifying a slip that each had been assigned — one of three — by a geometric shape located above it, docking in that slip and maneuvering out of it; observing a light buoy, noting and reporting a sequenced pattern of colored lights as they flashed; and navigating an obstacle course of floating stationary objects.

“I think the real challenge in this lies in the perception side of things,” says Karl von Ellenrieder, an ocean engineering professor at Florida Atlantic University, which entered a roboboat, with Villanova University, in the competition. “Seeing something is not that difficult, but once you see it, then you’ve got to figure out what it is and what to do about it.” This requires some “really good software,” he says.

FAU-Villanova’s robotic controls consist of a laser scanner that locates objects and gives their range and azimuth out to about 30 meters; a vision system — a small video camera that recognizes colors and uses data from the laser scanner to build a map of the environment; the computer software and controls; and two small electric trolling outboards. Ellenrieder says the robot’s top speed is 2 knots.

FAU has been working on self-driven robotic boats since the 1990s, when its focus was underwater vehicles. It has been fielding entries for national competitions for surface roboboats since 2007.

Navigating by computer and human

Interest in roboboats has grown during the past several years, von Ellenrieder says, driven by military, scientific and commercial applications. “In the military there’s a lot of interest in using them for interdiction of pirates and drug smugglers,” he says.

Like the unmanned police car that sits by the side of the road to slow speeders or deter burglars, roboboats could be sent on patrols to deter pirates or smugglers, he says. The military also is interested in using them to clear minefields and map coastlines or the sea bottom.

Mother ships can dispatch amphibious roboboats to beaches to clear beachheads of mines and obstacles. Ellenrieder foresees sending roboboats to assist in search and rescue, and commercial vessel operators using robotic systems to help them make their way through a cluttered seaway. “Part of the navigation job can be done by the computer and part by the captain,” he says. “They share the workload.”

The Harbor Branch Oceanographic Institution in Fort Pierce, Florida, uses a robotic undersea boat and a laser scanner to map ocean bottom to within a millimeter of accuracy and to measure water turbidity. Ellenrieder thinks undersea robotics could prove invaluable for mapping and monitoring coral reefs, and recording temperatures and water quality data at different depths in the waters around the reefs.

“I think we’re kind of in the early days of these [robotic ocean] vehicles,” he says. Software will have to be improved to compensate for wind and current and take into account not just stationary objects, but also vessels coming from many directions.

“I think at the current rate we’re doing things, [application] is going to stay mainly on the military side, and maybe on the oceanographic side and in open-ocean [commercial vessel] systems,” Ellenrieder says. “But eventually it should trickle down to yachts” — boats that one day could have autopilots that see, hear and make navigation decisions.

This article originally appeared in the November 2015 issue.