Progress has been made on a digging robot inspired by the unique style of an oceanic clam.

RoboClam can dig extremely efficiently by transforming the soil from a solid into a liquid, burrowing faster than any human equivalent.

RoboClam could have a variety of applications from anchoring underwater robots to subsea cable installation and mine neutralisation.

According to MIT researchers, the Atlantic razor clam should only be able to submerge itself into the soil by about 2 cm with the 10 N of force that it is able to exert. Instead, the razor clam is able to dig 70 cm into the soil.

The efficiency is achieved by the opening and closing of the clam's valves, or shells, which agitate the surrounding soil and turn it into a fluid, therefore creating less resistance and making it easier for the clam to move downwards through the soil.

“We have demonstrated that the robot is able to burrow into the soil with the same energy and depth relationship as the animal,” said lead author of a new research paper, Professor Amos Winter from the US Department of Mechanical Engineering

“Moving through static soil requires burrowing energy that scales with the square of depth. By fluidising soil and reducing drag, razor clams and the RoboClam can burrow with energy that scales linearly with depth.”

The RoboClam is controlled using a “genetic algorithm”, which continuously records and configures a number of variables as the robot is working.

The hope is that desirable traits - in this case digging behaviours - continue to get expressed through each generation of configuration.

This allows RoboClam to evolve, just as an organism does, into an optimised digging machine.

In their study, the researchers performed over 300 tests of the RoboClam in the razor clam's natural environment in ocean mudflats off the coast of Massachusetts.

The results showed that the RoboClam could achieve the same fluidisation of soil as the Atlantic razor clam and was able to dig into the soil nearly as efficiently.

“There are many applications where a small, lightweight, low-power, reversible anchor would be very valuable. At the moment we are working with an underwater robotics company... who produce vehicles that need to remain stationary in a current, and could therefore benefit from a small anchor,” Dr Winter said.

The full report is accessible here.