Underwater Robots could help Investigate Deep-Sea Operations

By Robert LeaJun 9 2021

Researchers are increasingly turning to robots to perform deep-sea operations to learn more about coral reefs and other underwater ecosystems. 

The world’s coral reefs provide a habitat for a wide range of aquatic species, ensuring that the oceans are beautiful and diverse ecosystems. However, the increasing warming of the oceans due to climate changes and other stressors such as increasing levels of pollution are causing bleaching events at increasingly short intervals, thus rapidly depleting corals.

Projects are currently underway to save coral reefs, but any rescue attempt for these living ecosystems requires knowledge, as do models of how rapidly coral reefs are shrinking. And collecting information about organisms that exist beneath the waves isn’t always easy. This is especially true when human divers and human-manned vehicles struggle to squeeze into the tight spaces found in and around coral reefs. As a result, even the most delicate craft could cause damage to incredibly delicate corals  —  a risk that runs in contradiction to reef-rescue operations.

To combat this, researchers across the globe are hard at work developing robots that could help us investigate the secrets of a variety of deep-sea creatures, including coral reefs. 

These robots  —  in various developmental stages  —  range from devices that operate with the same systems that power the Mars Ingenuity Helicopter, to soft-bodied machines that can squeeze into tight spaces without causing damage, and even robots that can match human-operated video systems in terms of observational skill.

Making Robots that See Coral Reefs As Well as Humans

A new research project is pioneering the use of small low-cost robots for coral reef reconnaissance. This could help combat some of the issues associated with the use of diver-operated vehicles to monitor coral reefs, including but not limited to restrictions on depths that can be studied, immersion duration limitations, and restrictions on the frequency of dives a human is permitted to make per day. 

The big question that the team aimed to answer in a recent study published in the journal Remote Sensing in Ecology and Conservation¹ is can a robot system perform observations as well as those gathered by diver-based vehicles?

The team set about observing tropical fish groupings from 13 fringing reefs around Mayotte Island located in the Indian Ocean with both a scuba-diver piloted Diver Operated Video system (DOV) and a semi-autonomous underwater vehicle (SAUV). The system tested by the team was operated from the surface and the study marks the first time such a platform has been directly pitted against a diver-operated observation vehicle.

Amongst the data collected were species richness and the total biomass of nine highlighted species of fish. The team discovered that the semi-autonomous robot recorded significantly higher biomass for the targeted species, something that they believe is a result of the SAUV recording larger individuals due to human avoidance behaviors in the fish species. 

Ultimately, the researchers found from the total of 9223 fish from almost 200 diverse species they studied the SUAV could obtain measurements of diversity throughout coral reefs that were on par with methods that rely on human divers. 

Despite this successful test, the SUAV tested by the team may not be ready for deployment just yet. The authors point out that SAUVs as they currently exist rely on cabling to connect the system to its human operators, something that limits movement and can prove to be a significant tangle-risk  —  especially when investigating the tight restrictions of coral reefs.

Despite these drawbacks, the research team believes that marine ecology should soon be revolutionized by massive leaps in robotic technology as well as advances in data processing. Help could be at hand from an unusual source. 

How Does a Robot Connect the Surface of Mars to the Oceans of Earth? 

When it comes to exploring the world’s oceans NASA may not be the first governmental organization you think of. Yet space isn’t the only frontier that NASA is exploring. The organization has teamed with National Oceanic and Atmospheric Administration (NOAA) to bring the technology that helps the Ingenuity helicopter soar over the vistas of Mars to Earth’s oceans.

The collaboration has resulted in creating the Orpheus robot², a new class of autonomous submersible machine that will search the ocean floor to answer mysteries beneath the waves in the same way the Ingenuity copter investigates the landscape of the Red Planet. 

Orpheus is considerably smaller than the current generation of high-power submersible devices that investigate the ocean floor. This is achievable thanks to the fact that the camera system, lights and Terrain-relative navigation system upon which the robot relies are all relatively low-powered.

Orpheus operates using a vision-based navigation system called visual-inertial odometry (xVIO), which helps it identify features like rocks, shells, and corals, setting them as waypoints to help create 3D maps of the ocean floor. 

The researchers behind the system hope that in the future, it will help map some of the most extreme ocean environments like trenches and ocean vents. But, before even that stage is reached, the robot could map less violent environments such as those that coral reefs enjoy.

NASA believes that the testing of Orpheus in our oceans will help develop the system to the stage at which its technology could be co-opted to investigate the oceans of other worlds such as Europa  —  one of Jupiter’s moons which is often considered the most likely place in the solar system other than Earth to harbor life. 

The system began a two-week trial run at the end of May 2021, launching from Port Canaveral in Florida aboard the NOAA vessel, the Okeanos Explorer. 

As impressive as these robots are, they still carry a significant risk of damaging corals meaning such operations that could ultimately help save corals do come at a cost. But, what if researchers could develop a soft-bodied robot that can weave its way through coral reefs without causing physical damage?

Hard Science with Soft Robots 

One of the most visually striking designs for a potential coral-weaving soft robot is the robotic jellyfish designed by a team of US scientists hailing from the Office of Naval Research and Florida Atlantic University (FAU)³.

The robot is one of a series of biomimetic soft machines that take their inspiration from nature, with jellyfish picked as a template by the scientists' thanks to the animal’s impressive swimming ability and the skill with which they dodge and weave through tight oceanic spaces.

Though this isn’t the first jellyfish-inspired machine, what sets this project apart is the fact that the team chose to use a propulsion system that relies on a soft hydraulic network. 

That means that this robot with a design that resembles the larval stage of the moon jellyfish species, formally known as Aurelia aurita is not just an incredibly gentle investigative tool, but is granted natural buoyancy from the water that fills the system. 

The machine is equipped with eight tentacles which are inflated by pumps that fill them with water from the surrounding environment. Because the tentacles are elasticated, when they are relaxed they naturally pump the water back into the robot’s surroundings.

Testing the jellyfish robot the researchers found that it could swim through openings that were narrower than its own diameter. The team hopes that in the future the addition of environmental sensors and a deep learning navigational algorithm could help the robot assess for itself which gaps it can or cannot weave through. 

The ability to be more self-reliant is something that has been built in to another soft robot inspired by nature. MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) recently unveiled a soft robot named SoFi with design that closely resembles the morphology of a real fish.

This natural shape allows SoFi to swim naturally through ecosystems alongside real fish. SoFi’s other remarkable qualities include its ability to control its own buoyancy and use its flexible body, tail and fins to handle currents so that it might swim in straight lines, turn and dive up or down.

All of these qualities make these nature imitating soft robots seem like an ideal tool for the investigation and rescue of coral reefs. 

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