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A giant subsea snake robot

A giant subsea snake robot

Published 10 August 2017
It most resembles a giant snake undulating through the water. But this snake-like robot can work in the vast ocean depths. And perhaps one of its relatives will be able to travel to outer space.
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This robot looks like a black-and-white sea serpent that can wiggle and writhe through the ocean's depths. Photo: Eelume

It’s a kind of anaconda, and its first iteration was even named “Anna Konda.” Now, a full decade later, the snake is almost full-grown. And the petroleum industry is interested.

“Our snake robot is an ultra-flexible vehicle,” says Arne Kjørsvik, CEO of Eelume, a spin-off company from NTNU.

Pål Liljebäck, Arne Kjørsvik and Kristin Ytterstad Pettersen with the snake robot that will be ready for action in 2019. Photo: Julie Gloppe Solem, NTNU

Pål Liljebäck, Arne Kjørsvik and Kristin Ytterstad Pettersen with the snake robot that will be ready for action in 2019. Photo: Julie Gloppe Solem, NTNU

The snake-like robot is flexible and can manoeuvre in confined spaces, such as subsea installations on the seabed. It can help with inspections, but also with making repairs and operating valves. The robot was developed in Trondheim by researchers from NTNU and SINTEF.

“The goal is to make the snake robot as autonomous as possible,” says Professor Kristin Ytterstad Pettersen at NTNU’s Department of Engineering Cybernetics.

Pettersen helped launch Eelume, and has been involved in developing the robot’s motion control systems. She has 25 years of experience with marine vessel control systems, including self-propelled underwater robots, and has contributed greatly to the snake robot’s autonomous underwater capabilities.

The robot should be able to move as independently as possible and with as little need for surface control as possible.

Two worlds

The snake robot consists of several interconnected modules. In this way, each module is an independent link, but the modules also work together. The design combines the best of several worlds.

Torpedo-shaped AUVs can cover long distances but don’t have manipulator arms. Then there are working ROVs that can make small repairs and operate valves, but these are large and typically require a surface vessel to control them. Observation ROVs are small and fit into tight spaces, but they can’t fix things.

A snake robot can do all these things. It can straighten itself out and swim like a torpedo-shaped AUV over long distances. The snake robot itself is a dexterous robotic arm that can carry out light intervention tasks, and at the same time it is slender and flexible and can manoeuvre in narrow places. It becomes an assistant that can live underwater until you need it to perform a job, whether it’s doing an inspection or being a gripper tool.

“It’s unique,” says Kjørsvik.

Eelume’s headquarters is ideally situated only a few metres from Trondheim Fjord. An indoor pool to test the technology is also available as needed, but nothing beats ocean practice where scientists can test the robot under different current conditions, in salt water, for visibility problems and at great depths. The Trondheim Fjord is over 600 metres deep at its deepest.

The article continues under the picture.

The robot consists of several interconnected modules that work together, a bit like advanced “snake Legos.” It combines the best of several different technologies. Photo: Eelume

The robot consists of several interconnected modules that work together, a bit like advanced “snake Legos.” It combines the best of several different technologies. Photo: Eelume

Down to 500 metres – for now

Currently, the robot has been tested down to 150 meters, but that’s not deep enough.

“Now we’re developing a model to handle a depth of 500 metres. It’s a totally manageable job,” says an enthusiastic Pål Liljebäck, Eelume CTO and co-founder.

The snake robot can straighten out and swim like a torpedo-shaped AUV over long distances. Photo: Eelume

The snake robot can straighten out and swim like a torpedo-shaped AUV over long distances. Photo: Eelume

Liljebäck says he lives and breathes for the snake robot. He thinks it’s amazing to be first in the world with something.

Eelume is open to unusual ideas and ideas that may never have been thought before. The result is a snake robot that will soon be ready to hit the market. Many years of work go into a model that can be put to practical work on the sea shelf.

The research on snake robots began in 2004. Several city fires ravaged Trondheim around this time, and the initial idea was to build a robot that could get into a burning building and help put out the fire. The technology evolved from there, with Eelume at the forefront.

Harder times provide opportunities

“We’re aiming to test an operational subsea installation as early as 2018, and deliver a ready-to-use model in 2019,” says Kjørsvik. “It’s not the technology we’re waiting on, but everything else around it.”

In other words, some companies – but not all – are willing to invest in new technology and lay the groundwork to implement it. Eelume has an advantage through working closely with industry itself. Statoil and Kongsberg Maritime are deeply involved and interested.

“We have to build acceptance for new methods,” says Kjørsvik.

The model is approaching the capability for practical use. But companies that already have a good way to carry out the tasks that the snake robot can perform may prefer to stick to their tried and true method even if it takes a few extra weeks. A tougher economy in the oil and gas industry could open the door for new work- and time-saving technology.

The robot becomes an assistant that can live in the subsea until needed to perform a job, whether it's doing an inspection or using a gripper tool. Photo: Eelume

The robot becomes an assistant that can live in the subsea until needed to perform a job, whether it’s doing an inspection or using a gripper tool. Photo: Eelume

Snake Legos

Currently the snake robot has an umbilical cord. Cables connect it to control systems and power sources on the surface. But battery power is coming soon.

The goal is for the snake robot to connect to docking stations on the seabed. The robot is so robustly constructed that the maintenance intervals – when the robot is brought to the surface – will start at three months, then increase. The snake consists of individual modules.

“It’s sort of like ‘snake Legos’,” one of the scientists jokes. Well, maybe… but definitely more advanced than even Lego Technic.

Researchers from NTNU’s close collaborative partner SINTEF are working with the European Space Agency to consider how snake robots could be used in space, such as on the International Space Station or Mars or to explore the surfaces of comets.

Contact

Arne Kjørsvik