'RoboClam' Could Anchor Submarines

A new burrowing robot for anchoring miniature submarines has been developed - inspired by the humble razor clam. "RoboClam" could be used to lay undersea cables, and potentially even destroy mines, its inventors say.

The device mimics the digging action used by razor clams to turn solid soil into liquid "quicksand", helping them slide through. They set out to design a new low-power, light-weight anchor for autonomous underwater vehicles.

The MIT researchers say their robot digs as fast as a razor clam. Compared to existing anchor technology "the razor clam is about 10 times more efficient," Dr Nordstrom told BBC News. To dig for half a kilometre, it would only use the energy in an AA battery.

To find out the razor clam's secret, they studied its digging action and modelled it mechanically. The repeated open-shut of the clam's valves turned the hard-packed soil around it into quicksand. "The clam's trick is to move its shells in such a way as to liquefy the soil around its body, reducing the drag acting upon it," said Amos Winter, of MIT's Department of Mechanical Engineering. "Pushing through sand costs a lot of energy. But if the sand is excited, it's actually very easy. That's the trick," added Dr Nordstrom.

The first "RoboClam" can only reach 20cm, and requires a significant rig of machinery to propel it. But having demonstrated the principle, the team now aims to develop a larger, self-contained unit, that can burrow more than 10 metres.This could be used to anchor larger vessels, and may have military applications - such as detonating mines, the researchers suggest.

Source: bbc.comAdded: 11 April 2014