The Atlantic razor clam has the ability to burrow vertically into the sand at a rapid pace, using very little energy. Inspired by this creature, Amos Winter, the Robert N. Noyce Career Development Assistant Professor of Mechanical Engineering at MIT has developed a device known as the RoboClam, which can dig itself into the ground.
In order to create a device that could match the razor clam’s ingenuity, Winter had to figure out the intricate mechanics behind the mollusc’s action. It digs by retracting its shell causing the surrounding soil to collapse around itself. As it contracts it draws water into the falling soil creating quicksand. The clam’s timing is crucial; if it moved too slowly the particles of sand would collapse without fluidizing, too quickly and the sand particles would stay in place.
The researchers created a prototype that has the ability to fluidize sand particles in the same way. Though RoboClam doesn’t look much like its biological counterpart, it burrows as efficiently. The small machine has a rod which pushes down into the seabed while its two arms open up and quickly close, stirring the sand around it. The rod pushes the robot down into the liquid sand and the motion repeated.
Winter and his team continue to refine the machine. At the moment RoboClam can push down with 80 pounds of force, that’s 36 times more than a razor clam. It can dig to a depth of 15 inches. Eventually Winter hopes to develop a robotic clam that can dig deeper than 28 inches at a speed of around 0.4 inches per second.
The robot is so efficient that it could be used to anchor underwater vehicles. “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. “You wouldn’t want the vehicle constantly spinning its propellers in order to stay in one place because that just wastes energy, so it would be nice if you could just deploy an anchor and maintain your position without expending any energy.”
Other potential uses include; ocean surveys, laying submarine data cables, surveillance and to destroy underwater mines.