Underwater robots that predict disruptive waves could lessen cost of offshore renewables

Engineers have developed computational and experimental tools to enable autonomous robots to maintain a steady position at sea, an advance that could reduce the cost of producing offshore renewable energy.

The unpredictable nature of waves has limited the use of robots in the upkeep of offshore platforms
The unpredictable nature of waves has limited the use of robots in the upkeep of offshore platforms - AdobeStock

The researchers at Edinburgh University trialled their system at the institution’s FloWave testing tank, using wave data captured by a buoy in the North Sea to mimic the types of conditions robots might work in.

Wave-detecting devices are tethered to the seafloor and measure the direction and height of incoming waves, relaying the information in real-time to a robot working nearby. This enables the uncrewed machine to pre-empt complex future disturbances in the water, precisely counteracting these to maintain a stable position.

Findings indicate the system is compatible with robots operating near the surface and those working at greater depths.

The team said the new technology improves on conventional control systems that operate in a corrective fashion. These are prone to responding slowly to the fast-changing disturbances of the ocean, making them less reliable in such hazardous environments.

In a statement, Dr Kyle Walker, who developed the work as part of his PhD at Edinburgh University, said: “A major limitation at present is robots’ ability to perceive and counteract environmental disturbances effectively, which fundamentally restricts the current use of small subsea vehicles. By forming a prediction of future wave disturbances and integrating this within the control system, we're able to expand this range with little to no change to the robot hardware.

“In terms of translating this technology into the field, this is a huge benefit and makes our system applicable to most vehicles currently available on the market.”

Future research aims to improve autonomous machines’ ability to perform precise tasks – such as using robotic arms to detect rust or fix electric equipment – while holding a steady position in water.

The study, published in the International Journal of Robotics Research, received funding from the Engineering and Physical Sciences Research Council. An open access version of the paper is available here.

The work was a continuation of the now-finished ORCA Hub project, an initiative to support the green energy transition led by Heriot-Watt University and Edinburgh University.

Dr Francesco Giorgio-Serchi, of Edinburgh University’s School of Engineering, who led the study, said: “Increasing the use of autonomous robots to help maintain offshore renewable installations could have a transformative effect on cutting the cost of producing clean energy.

“Advancing this technology further could help bring about a step change in the adoption of unmanned robots at sea and drastically increase the degree of automation in the offshore sector.”