March 3, 2004

Robo-Snail

Researchers at MIT have created a robot that imitates the locomotion of a snail. At first blush, this might be considered to be against the direction that we generally want robots to go, but snails have a very robust motion system, able to climb over obstacles that would render a wheeled vehicle useless.

robosnail.jpg Real snails travel on their single foot along a trail of mucus, a slimy fluid secreted by a special gland in the foot. Snails move by pushing the mucus between their foot and the ground or other surface. Snail mucus is an example of a non-Newtonian fluid, a type of fluid of particular interest at MIT’s Hatsopoulos Microfluidics Laboratory, where Hosoi and Chan work. Unlike Newtonian fluids such as oil or water, non-Newtonian fluids change their properties and thicken when they're subjected to stress, such as downward pressure from a snail's foot. Since snails use different mechanisms to move, Hosoi and Chan designed two RoboSnails, each mimicking a different method of snail locomotion.

The team's first RoboSnail imitates a snail mechanism that Hosoi compares to the up-and-down motion of ocean waves. "There's a wave that propagates along the bottom of the snail’s foot," explains Hosoi. "And the wave can either propagate in the direction that the snail is moving, or it can propagate backwards." The first RoboSnail's version of mucus is silicon oil combined with clay particles. Its body is a series of plastic plates strung along a wire helix that is connected to a small motor Chan borrowed from a toy car. When the motor is running, the plates create a wave in a rubber foot.

Posted by elkaim at March 3, 2004 11:42 AM