Can you dig it? Robotic clam burrows into ocean floor

Computerworld - Usually well known for what they add to chowder or linguine, clams are now inspiring robotics research.

Scientists at MIT are studying the digging capabilities of the razor clam to figure out how to make a robot that can dig into the ocean floor, hold fast and then release and dig itself back out. The machine, dubbed the RoboClam, could be used for smart anchors, detonators for underwater mines or tethers for robotic submarines that need to be frequently repositioned to monitor currents and water temperatures.

The news about the robotic clam came out just days after another team of MIT researchers announced that they have used computer modeling to boost the output and efficiency of solar cells while lowering the cost of solar power.

"Our original goal was to develop a lightweight anchor that you could set, then easily unset -- something that's not possible with conventional devices," said Anette Hosoi, an associate professor in MIT's department of mechanical engineering, in a statement. "We thought, 'Is there an animal that's well adapted to moving through sediments on the sea floor?'"

The answer to that question was the razor clam, a bivalve mollusk that has a long, narrow shell that's generally about an inch wide and seven inches long. The clams are known to dig down at a rate of a centimeter a second, according to Amos Winter, a graduate student who worked on the project. They can dig to a depth of about 70 centimeters.

Winter noted in a report that razor clams are incredibly strong. When measuring the force it takes to pull a razor clam out of the ocean bed, researchers found that the clams are stronger than even the best man-made anchors by a factor of 10.

Winter reported that the razor clam can dig so quickly and hold on so tightly because of an odd series of steps it takes when burrowing. Its "foot" wiggles into the sand and then the clam makes a quick up-and-down movement, while also opening and closing its shell. Researches noted that these series of movements essentially turn the surrounding soil into a type of quicksand, which reduces the drag on the clam's shell and enables it to propel itself with speed and force.

According to MIT, Winter built a RoboClam prototype that includes pressure regulators and pistons that control the force it uses to dig. Researchers are now putting the robot through a series of tests. There was no indication how soon it could be used commercially.

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