How Fish are Changing the Science of Robotics

What do fish and robots have in common? As it turns out, more than most people would imagine.

For decades, robots have been used to perform a variety of tasks considered too dirty, dangerous, dull, expensive or complex to be suitable for humans. These technological wonders are widely used in manufacturing, packaging, transport, space exploration, surgery and laboratory research.

Now, scientists and technicians around the world are developing a new generation of robots. These models, unlike previous versions, can be used on or in the water. Jobs for which they are well-suited include environmental monitoring, security surveillance, fish study, search-and-rescue operations, archaeological exploration, industrial applications and much more.

To create these fishbots or robo-fish, as they’re often called, researchers have spent millions of dollars and countless hours studying real fish. They know that engineering a robot that works efficiently in water will be simpler and less time-consuming if they borrow ideas from nature that can serve as the basis for their designs.

By conducting in-depth computer and photographic studies showing how eels, tuna and other species swim, for example, scientists have learned how to create a variety of robots that not only propel themselves through the water faster and more efficiently but resemble their natural counterparts so closely they can swim in real schools of fish to help scientists conduct behavior studies.

Scientists also are learning how fish in the same school can coordinate with each other when swimming together. The things they discover will be used to develop algorithms that can optimize maneuvering systems in underwater robots.

Revelations such as these have set the stage for a robo-fish revolution that is happening right now. Check out some of the amazing innovations that already have resulted.

RoboSalmon

One of the first robotic fish was developed at Scotland’s University of Glasgow in 2007. Called the RoboSalmon because it was modeled on the anatomy of an Atlantic salmon, this autonomous underwater vehicle (AUV) was created to determine if an AUV could be driven using a fish-like tail instead of a propeller.

The engineering professionals who created RoboSalmon found that its fish-tail propulsion system offered several benefits over conventional propeller-driven models, including more efficient propulsion, increased maneuverability and decreased disturbance of surrounding water. That made RoboSalmon ideally suited for tasks such as environmental monitoring, where the presence of a conventional vehicle with a propeller may disturb the surroundings; and military applications where use of a tail may provide more stealth than a noisy propeller.

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Because the robot uses a tail for movement, it also can glide through the water in a way that looks more natural to aquatic creatures. Zoologists were quick to add a built-in camera that could broadcast images of live fish back to the device’s operators, allowing the study of fish in their natural habitat.

The groundbreaking work conducted with RoboSalmon led the way for the development of many other fishbots in the decade that followed.

A New Fish in School

Another creation useful for scientific studies is Robofish, a lifelike, plaster-cast model of a three-spined stickleback created in 2010 by a team at Great Britain’s University of Leeds. The goal was to create a computer-controlled fish that could fool other fish into thinking it’s one of them. This would allow it to interact with other fish in a school so researchers could learn more about individual and group dynamics.

Robofish worked even better than expected, allowing the researchers to actually control the movement of fish schools.

This “allows us to study quite complex situations such as aggressive, cooperative, anti-predator and parental behavior,” said PhD student Jolyon Faria who led the experiments. Researchers believe the insights thus gained could help improve fisheries management in both freshwater and marine environments.

Envirobot

One of the most recent and interesting innovations in robotic fish is Envirobot. Modeled after the lamprey eel and created using 3D printing, this snake-like, sensor-laden robot swims on the water’s surface to collect samples and real-time data for environmental scientists. By tracking pollution levels, it is hoped Envirobot will eventually be able to pinpoint heavy metal runoff from a mine or illegal waste dumping by a chemical company.

Created by a team of researchers from École Polytechnique Fédérale de Lausanne in Switzerland, Envirobot has a modular design that allows scientists to swap out the pieces they need.

“Those modules, by default, don’t have any sensors,” explained Alessandro Crespi, a member of the Envirobot team. Researchers can develop their own sensors and technology to load in, like those already being used to ascertain temperature and electrical conductivity in Lake Geneva water samples. A pH sensor will soon be available, and an unusual biosensor that uses tiny contaminant-sensitive crustaceans called Daphnia to track pollution.

“The Daphnia sensor is actually able to measure pollutants without knowing what it’s looking for,” said Crespi. “That’s important when scientists don’t know whether a body of water is polluted.”

The water may look fine, but Daphnia can tell whether there’s a problem. And putting tiny tanks of Daphnia on board the eel-shaped robot takes the test out of the lab and into the field. “We can actually really achieve some kind of real-time detection,” said Crespi.

Pollution Patrol

In Spain’s Atlantic waters, robots that resemble big yellow fish are also waging war on pollution. Developers haven’t given them a snazzy name yet, but these fishbots being tested by the SHOAL consortium possess artificial intelligence that enables them to manage multiple problems, including avoiding obstacles, knowing where to monitor pollution, finding the source of pollution, maintaining communication distance from the other fishbots and returning to be recharged.

“The idea is we want to have real-time monitoring of pollution, so if someone is dumping chemicals or something is leaking, we can get to it straight away, find out what is causing the problem and put a stop to it,” said Luke Speller, a senior scientist at the BMT Group, a technology consultancy. “Previously, samples were only taken about once a month. In that time, a ship could come into a harbor, leak some chemicals, then be gone.”

These 5-foot-long robo-fish are on duty continuously. They mimic movements of real fish so they don’t adversely affect marine life and have sensory arrays to monitor contaminants, oxygen levels and salinity. When a robo-fish sniffs out pollution, it hunts down the source and reports back to a base station and other robo-fish.

Remora Robot

One of the most unique new fishbots was inspired by the remora, a fish that clings to larger marine animals like sharks and whales, feeding off their hosts’ dead skin and feces. Remoras do this using a sucker-like organ on their head. This disk has sturdy, flexible membranes that can be raised and lowered to generate suction. By sliding backward, the remora can increase the suction, or it can release itself by swimming forward.

Li Wen, a robotics and biomechanics researcher at China’s Beihang University, got the idea for a remora-inspired robot when he was a postdoctoral researcher at Harvard University. He and his advisor were designing 3D-printed sharkskin. While looking at photos of sharks, Wen noticed remoras attached to the large predators. Struck by the fact that no one had tried to make a biorobotic remora disk, Wen and his colleagues decided to tackle the project themselves.

To do so, they used 3D printing to create a specialized disk with multiple sections that ranged from skin-soft to downright rigid. To this they added six pneumatic actuators – basically little air pockets – that would inflate and deflate on cue so the disk would move just like a real remora disk.

The result is a 5-inch-long robot that resembles the head of a shaving razor, but much larger and with far more blades. To test it, the researchers attached the robot to a variety of underwater surfaces – some rough, some smooth, some rigid and some flexible. The robot clung quite nicely to all of these and required up to 340 times the weight of the robot itself to pull it off. Using a remotely operated underwater vehicle, it could be attached to any of these surfaces in less than four seconds.

Adhesive robots are nothing new, but the remora is one of the first options roboticists have had for underwater attachments. Other sticky bots, like ones inspired by tree frogs and geckos, don’t work well when submerged. The remora bot could be used to attach things to any broad underwater surface, Wen said, or to allow an underwater robot to maintain infrastructure like submerged oil pipes. Remora robots could even be used as tags for tracking the movements of marine animals, he said. After all, what’s one more hitchhiker?

Fishbot for Fishermen

If all this talk about fishbots makes you wish you could own one, well, now you can. And this one, the PowerRay by PowerVision, is made especially to help fishing enthusiasts find and catch more fish.

The PowerRay doesn’t really resemble a real fish, but the things it can do are incredible. It can dive up to 98 feet at a maximum operating time of four hours and is equipped with a wide-angle camera that shoots 4K video or 12 MP stills and transmits in real-time to a smartphone. With the robot’s mobile app, users view the real-time photo or video and can also view the real-time position of the PowerRay, select travel mode, speed and light settings, and operate the camera. The robot also is optionally available with VR goggles that provide an underwater view, which also allows the user to interact with and manipulate the robot underwater via head tilting.

Available with the PowerRay is the PowerRay Fishfinder, which is a stand-alone sonar system that detects fish and transmits images of the underwater landscape, temperature data and alerts. An internal Wi-Fi system enables users to operate it from distances up to 262 feet. The sonar system, which is equipped with an internal blue-hued fish-luring light, can detect fish up to 131 feet below the robot.

PowerRay also can be purchased with an optional, remotely operated, precision bait drop. Users secure bait to the device and operate the PowerRay to deliver the bait precisely to the desired location. One can then monitor and control the entire fishing experience through real-time viewing in the PowerRay mobile app.

“Recreational fishing is one of the lifestyle areas that has not seen major technology breakthroughs,” said Wally Zheng, CEO of PowerVision Technology Group. “By introducing PowerRay, PowerVision is completely changing the way we have been fishing the past 7,000 years. Through innovating the fish-finding technology and features, providing the thrill of finding the catch and an immersive underwater experience through virtual reality, PowerRay is going to provide more efficiency, thrills and fun to fishermen around the world. Recreational fishing will never be the same again.”