A "RoboClam" developed at MIT has duplicated the trick of an Atlantic razor clam, digging into the sea bottom using very little energy, suggesting uses from setting anchors in the undersea soil to destroying underwater mines.
Mechanical engineering Professor Amos Winter studied the razor clam and its ability to dig through sediment at speeds of up to a centimeter a second despite its rigid shell.
"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," Winter said in an MIT release Monday.
"As it begins to dig, the clam contracts its shell, releasing the stress between it and the soil around it, creating a localized landslide. Sucking water into this region of failing soil, the clam can create a fluidized substrate, or quicksand, that it can move through easily," Winter added.
Using this technique, the clam can burrow along for as much as half a kilometer using no more energy than is contained in a AA battery.
Hoping to duplicate the creature's digging ability, Winter and his colleague Anette Hosoi, another MIT mechanical engineering professor, built a mechanical puppet clamshell, consisting of two halves that can move together and apart like an accordion.
Winter and Hosoi began working on the RoboClam in 2006, with the goal of developing a method autonomous underwater vehicles could use to anchor themselves to the sea floor without expending too much of their limited battery power.
"You might be operating these vehicles in a current, and need them to be stationary -- for example, to monitor a biological situation, or for military purposes," Winter said.
In their initial tests of RoboClam the researchers used compressed air to power the movement of the device's shells, but are working to develop an electronic version for use in underwater vehicles.
A possible additional use for the RoboClam, Winter said, would be laying underwater cables in water too shallow for cable-laying ships, which usually requires human divers in an expensive and time-consuming process.
"Having a system that could just latch onto the cable, work its way along, and automatically dig it into the soil would be great," Winter added.
Winter and Hosoi have described their research in a paper to be published in the journal Bioinspiration and Biomimetics.
