E-luminating the deeps

Elaine Maslin

May 1, 2017

Eelume has made a splash with its snake-like underwater robot, despite its lithe form not initially having been destined for a life subsea. Elaine Maslin sets out the detail.

Eelume (a shortening of electric and luminaire, or light) trying out underwater life.
Photos from Eelume.

This year a creature quite unlike any other seen before in the oil and gas industry will take some tentative steps towards full-fledged realization. Its makers believe it could herald a new era in subsea operations, towards the subsea resident robotics concept championed by others, but with a somewhat different shape.

Norwegian start-up Eelume’s multi-articulated joint, snake-like subsea robot is being designed to be a subsea resident inspection, maintenance and repair (IMR) tool, able to transit multiple kilometers between subsea tiebacks and remain subsea for long periods.

There are a number of approaches in this area, mostly centered around designing a vehicle from scratch, such as Subsea 7’s autonomous underwater vehicle (AUV) hybrid AIV (autonomous inspection vehicle), or by adapting currently available electric remotely operated vehicles (ROVs) (OE: October 2016).

Having a resident subsea vehicle is seen as attractive because it would make the vehicle available for inspection, and potentially for 24/7 intervention and maintenance operations, without the need for a support vessel.

A robotic arm

Eelume describes its unit, which would live in a subsea docking station, as a “self-propelled robotic arm” able to reach places conventional underwater vehicles cannot.

The vehicle’s shape and ability to flex means it can form a U-shape, effectively making it dual functioning – i.e. it could hold on to something or have a manipulating arm on one end and a camera on the other. It’s construction – multiple units, including its vertical tunnel thrusters and forward/back facing transit thrusters, as well as potential tools, connected with flexible joints – will also lend itself to a modular design, which can be interchanged, depending on its purpose, says Eelume CEO Arne Kjørsvik, who previously worked at Marine Cybernetics, which was acquired by DNV GL in 2014.

“We are quite sure this vehicle will [carry out] quite a lot of standard IMR solutions today,” Kjørsvik says. “It is like a snake, but also like a manipulator arm, which means you can put different tools on this arm to do different operations. It has easy access to constrained areas.

“But, we think the technology will also reshape the subsea business in the future. You might be able to construct subsea structures a bit lighter or easier as you don’t need to prepare it for work with a work class ROV.”

With tools like these, future subsea architectures could go one of two ways (or even both). One, where subsea facilities have power and communication links for the resident vehicle to dock into, helping to support the vehicle, but also making the architecture more complex. The other would be a separate power source and a communication link for the vehicle and in order to keep the subsea facilities simple.

Getting wet

Eelume and its predecessor on a Trondheim quayside. 

An 18cm-diameter, 360cm-long, 70kg prototype, has been built and tested at 150m water depth in a fjord in Trondheim, Norway, traveling at up to 4-5 knots. This year, it will be superseded by a slighter wider diameter (20cm) unit, but not much longer (just under 4m is thought to be the maximum these underwater tools should grow). The firm hopes to put a faster vehicle into service by 2019.

Testing, to date, has been via a tether, for power and communications, but these are set to be phased out and batteries for power and acoustics or wireless for communications brought in, as the machine is developed, inevitably making it a little larger, but not too much, Kjørsvik says, and the power will be much less than that required by a work-class ROV, he adds.

Kongsberg will inevitably be involved with its positioning and navigation capabilities, developed for the likes of its Hugin and Munin AUVs. This summer, the latest prototype, still on a tether, will be trialed with tools and in deeper water, at 500m. Next year, the plan is for the vehicle to go wireless, without a tether.

Fighting fire

 Eelume trying out underwater life. 

Eelume was formed in 2015 and is part owned by Norwegian maritime giant Kongsberg and NTNU (Norwegian University of Science and Technology). It has support from the Research Council of Norway and Innovation Norway, as well as Norwegian major Statoil. The company was spun-out from NTNU in Trondheim, but the technology itself has been under development since the early 2000s. Initially, the tool’s intention was that it could be used by fire fighters in Trondheim, who had to deal with fires in the city’s many wooden buildings. They had wanted a tool to hold a fire hose.

However, in 2014, someone had the idea to coat the unit in rubber and put it in water to see how it would swim. It turned out it could, and the idea to use it in the offshore industry was born. In 2016, Statoil signed a development contract with Eelume and the first wet-prototype was built not long after and tested in 150m water depth, carrying out inspection tasks and demonstrating its maneuverability.

Research work at NTNU has been behind the project, specifically around how to control a snake-like robot using NTNU-developed algorithms created to recreate how actual snakes move. Developments in battery technology, positioning systems, communication systems and subsea tooling technology, are also helping bring this technology to life, Kjørsvik says.

“The standard tools need to be recreated, they need to be a lot lighter than they are today,” he says. “Most tools have been hydraulic; however, more and more are electrified, and that is an enabler for us.”

Further development may see the materials that make up the unit change from aluminum and plastic to other lighter and stronger materials. “Today is about proving the concept of being a subsea resident,” Kjørsvik says, however. “Communication, batteries and control system are the most important steps for us now. There are a range of different tools out there which we have to adapt, but that is an engineering job.”

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Video: Eelume debuts snake-like underwater robot