23 Underwater Drones - The Boom in Robotics Beneath the Waves
By Tom Metcalfe, Live Science, 21 January 2018.
By Tom Metcalfe, Live Science, 21 January 2018.
Aerial drones have buzzed their way into almost every aspect of the modern world, from photography and television news coverage, to environmental monitoring and archaeology.
And many of the concepts developed for aerial drones are being adopted and adapted to work in a very different environment - underwater.
Here's a look at 23 of the many ways that drones are being used beneath the waves, by oceanographic scientists, archaeologists, militaries, commercial divers, photographers and undersea explorers.
1. Shipwreck Search
Photo credit: Woods Hole Oceanographic Institution
Concepts developed in aerial drones, such as greater levels of autonomy, are finding new expression underwater. Autonomy - the ability to take action without direct control - makes a drone more like a true robot and less like a remote-controlled device.
Although they lack of complete autonomy, very advanced remote-operated underwater vehicles, known as ROVs, have become a mainstay of scientific and commercial underwater operations, from undersea oil drilling projects to scientific research in the most extreme environments in the ocean.
The most celebrated ROV team are Argo, ANGUS and Jason Junior (shown above) which were used by the US research ship Knorr to discover the shipwreck of the Titanic in 1985 - after they had completed a top-secret mission to inspect the remains of a lost US Navy nuclear submarine, the USS Scorpion.
2. Robot ROVs
Photo credit: Schilling Robotics
The Deepwater Horizon oil spill in 2010 resulted in a gathering of the world's largest robotic underwater armada, as about a dozen large "work-class" ROV's struggled for months to stem the oil gushing from a shattered wellhead on the seafloor beneath 5,100 feet (1,600 meters) of water.
Among the lessons learned: making ROVs more autonomous, even while they remain tethered by an umbilical cable to a control ship on the surface. Advanced ROV's - like the Schilling UHD shown here above a test pool - already use pressure gauges, compasses and doppler sonar to keep themselves oriented; automating ROVs further could help to refine their awareness of what surrounds them, a feature that might have been useful navigating cables and moving gear in the Gulf.
3. Diving Buddy
Photo credit: Deep Trekker
Thanks to miniaturization, you don't need a support ship to operate an ROV. The electrical conductivity of saltwater makes radio communication very difficult underwater, so ROVs are connected directly to an operator by long umbilical cables to carry out expert tasks like underwater inspections.
A commercial example is the Deep Trekker drone shown above, which is controlled by a video-link handset that can be operated from the surface or by a diver in the water. When fitted with a multibeam sonar system that can "see" in dark or murky waters, the drone has been used by scuba divers to search for shipwrecks in Lake Huron, and to explore inside the protected wreck of the USS Arizona at Pearl Harbor in Hawaii.
4. Yellow Submarine
Photo credit: Lockheed Martin
Fully autonomous underwater drones offer advantages that are already being put to work by the oil and gas industry. Lockheed Martin's yellow Marlin drone submarine has been used to inspect offshore rigs and underwater pipelines, a sector that costs up to a billion dollars a year in the Gulf of Mexico.
The Marlin can take operate at depths of up to 1,000 feet (300 m) and keep going for up to 16 hours. An updated version of the drone, the Marlin Mk2 shown above, featured in a U.S. Navy technology demonstration that included launching a Lockheed Martin Vector Hawk aerial drone.
5. Deep Divers
Photo credit: Woods Hole Oceanographic Institution
Underwater drones have been used to explore the most extreme depths of the world’s oceans. The Nereus was a hybrid of an autonomous drone and a remote controlled ROV built by the Woods Hole Oceanographic Institution to explore Challenger Deep in the Mariana Trench near Guam, the deepest surveyed point of the world’s oceans, at a depth of 35,768 feet (10,902 m).
Nereus successfully reached the bottom of Challenger Deep in May 2009, but the vessel was lost in 2014 while exploring the Kermadec Trench near New Zealand, at a depth of 32,500 feet (9,900 meters), when it imploded due to high pressures as high as 16,000 lbs. per square inch (psi).
6. Wave Gliders
The most travelled drones on the planet are Wave Gliders, developed by California tech firm Liquid Robotics, which have covered more than 1.4 million miles of ocean so far. Each drone consists of a surfboard-sized "float" and a wing-shaped "sub" that hangs up to 26 feet (8 meters) under the water. The drones use wave motion and solar power to travel thousands of miles at sea without fuel, with applications in environmental monitoring, defense and maritime surveillance, and offshore oil-and-gas operations.
7. Ocean Gliders
Photo credit: Ben Allsup/Teledyne Marine
Autonomous ocean gliders, or underwater gliders, like the Slocum glider shown above, can convert small changes in buoyancy into forward motion. They are used extensively for scientific research at sea, such as remote water sampling, environmental monitoring, or acoustical surveillance over months and thousands of miles of ocean.
In 2016, ocean gliders equipped with microphones recorded the mysterious "Western Pacific Biotwang," which researchers think may be the never-heard-before call of a minke whale.
8. Underwater Mapping
Photo credit: Phil Short
Experts eventually foresee a fleet of underwater robots mapping the floors of the oceans, lakes and rivers - much like Google has mapped the streets.
Underwater drones have already been used to map underwater sites of importance. In 2015, the Sirius AUV, shown above, was used to map the Antikythera Mechanism were found, along with other treasures.
9. Fly and Dive
Photo credit: Rutgers School of Engineering
A drone that can fly and dive may seem like a cool gimmick at first, but there are numerous applications for such a unique talent. The 'Naviator' drone is being developed by a team at Rutgers University School of Engineering, who see it being used to inspect bridges both above and below the water, for search and rescue operations, and the evaluation of seaborne environmental incidents, like oil spills or algae blooms.
A fly-and-dive drone could also be used for research into wildlife species like whales that spend time both above and below the waves.
10. South China Sea Drone Drama
Photo credit: US Navy
In December 2016, a Chinese warship seized an underwater autonomous drone deployed by a US Navy oceanographic research vessel, the USS Bowditch, in the contested South China Sea region.
According to news reports, crew of the Bowditch were about to recover the drone after its mission when it was picked up by a Chinese warship instead.
11. Underwater warriors
In September this year the US Navy created its first dedicated underwater drone unit: Unmanned Undersea Vehicle Squadron One, or UUVRON 1 for short. The US Navy sees underwater drones eventually being used in "every spectrum" of naval operations, from mine hunting and surveillance to humanitarian assistance and scientific research.
The above image shows civilian contractors for the US Navy securing a Kingfish underwater vehicle, which can use side scan sonar to search for and investigate suspected naval mines and other objects of interest floating or on the sea floor.
12. Experimental Naval Drone
Photo: AUVAC
The US Navy's Naval Undersea Warfare Center (NUWC) has developed its Manta unmanned underwater vehicle as a modular test bed for autonomous underwater drone technologies.
The Manta UUV is over 30 feet long and carries a payload of up to five tons, which can include additional smaller underwater drones, for which it acts like a mother ship, and torpedo weapons.
13. Mantabot
The US Navy is also funding research into advanced underwater drone concepts like the swimming "Mantabot" developed at the University of Virginia, which uses silicone fins for swimming based directly on the cow-nosed ray, a species related to mantas.
The streamlined shape and swimming technique allows the drone to move quickly and quietly through the water using relatively little energy - a useful feature for underwater drones that would let them stay at sea for long periods without recharging.
14. Naval Drone Swarms
Photo credit: US Navy/Scott Youngblood
A recent briefing paper for the UK Parliament, as it considered whether to modernize or scrap its Trident nuclear missile subs, warned that advances in drone technology could soon make submarine warfare obsolete.
The report warned that swarms of cheap robot sub-hunters could blanket the oceans with acoustical and other sensors that could negate a submarine's ability to travel undetected underwater.
The US Navy has also experimented with autonomous boat drones to guard US ships and swarm enemy vessels.
15. Science Swarm
The world’s navies are not the only ones interested in swarms of underwater drones - scientists are too. Researchers at the University of Ganz in Austria have developed the CoCoRo swarm of more than 40 underwater bots to research how they can act together to accomplish various tasks underwater.
The autonomous drones in the CoCoRo swarm come in three different types, depending on their function, and use flashes of light to communicate.
16. Plankton Mapping Swarms
Photo credit: University of California-San Diego
Scientists have also used swarms of underwater drones to investigate environmental events like plankton mating.
Researchers at the University of California-San Diego build a swarm of 16 autonomous underwater drones and dropped them off the coast.
The drones were told to stay at a depth of 33 feet, and to drift with and map the "internal waves" that enable by plankton species to mate.
17. Floating Sensor Networks
Tech start-up Hydroswarm wants to build thousands of pumpkin-shaped underwater drones to map the oceans and act as a surveillance system for everything from oil pollution to illegal fishing to drug smuggling.
The EVE underwater drone - standing for Ellipsoidal Vehicle for Exploration - was developed by Sampriti Bhattacharyya, a mechanical engineer at the Massachusetts Institute of Technology. Bhattacharyya says the EVE drone is designed to be used independently or as part of a swarm of underwater drones that could create a Google Maps for the oceans.
18. Underwater Robot Miners
Photo credit: VAMOS Project
Underwater robots designed to work in hazardous flooded mines were tested at a china-clay pit in the UK in October this year.
The EU-funded VAMOS project (Viable Alternative Mine Operating System) is developing three types of underwater drones to extract minerals from abandoned, flooded mine sites considered too dangerous or costly to access.
Mines deeper than the local water table usually fill with water unless it is pumped out - eventually they are abandoned and flood completely. The developers say it makes more sense to reopen an existed mine with robot miners, rather than excavate a new pit.
19. Drones Under the Ice
Photo credit: Lars Chresten, Lund Hansen
Underwater drones are used by scientists to explore some of the most remote regions of the oceans - including the coldest waters on earth, beneath Antarctica's ice shelves, where the temperature is a few degrees below the normal freezing point because of the salinity of the seawater.
Researchers have deployed torpedo-shaped drones from holes cut into the ice, equipped with radiometers to measure the light absorbed by clumps of ice algae growing on the bottom of the ice shelf.
Based on the drone measurements, scientists are able to estimate the total amount of algae growing on the ice - an important source of food in the ecosystems beneath the ice shelves.
20. Wartime Wreck Search
Photo credit: Project Recover
Underwater robots have also been used to search for the downed wrecks of American warplanes from World War II, as part of an effort to discover the final resting places of their crew.
"Project Recover" uses a variety of new underwater technologies, including autonomous underwater drones equipped with sonar and cameras, to make a thorough and regular search of the ocean floor for wartime plane wrecks, which are often very hard to spot.
In 2014, Project Recover divers using drones found two World War 2 warplanes in the islands of the Republic of Palau in the Western Pacific Ocean, and in 2016 they found two lost B-52 bombers near Papua New Guinea.
21. Anti-Lionfish Drones
Photo credit: Robots in Service of the Environment
A non-profit group called Robots in Service of the Environment (RSE) is developing an underwater drone to hunt down and terminate Asian lionfish, which have become a serious threat to coral reef systems in the Western Pacific, where they have no natural predators.
The deep-diving drone is guided by controllers at the surface to track and close on the invasive fishy enemy, before sucking them into a containment tube and stunning them with an electrical charge - one drone can humanely dispatch up to ten lionfish before returning to the surface with its catch.
22. Manta Ray Drone
The BOSS Manta Ray is an autonomous underwater drone developed by German robotics company Evologics, which specialises in aerospace and maritime robotics.
The drone is designed to mimic the manta's flexible body, which gives it the ability to control its depth very precisely with its large wings, while its "flapping" mode of swimming is very energy efficient. It is also equipped with jet thrusters to give it a high-speed mode.
23. Robotic Jellyfish
Photo credit: Festo
Like Evologics, some other underwater drone makers technology companies are also looking for ideas from nature - a concept known as biomimicry.
German engineering company Festo has developed its Aquajelly underwater robots to mimic the swimming motions of jellyfish. They can also communicate with each other - something real jellyfish probably can't do - to coordinate their behaviour.
