New Microscopic Robot's Tiny Step Is a Huge Leap

Brian Handwerk
for National Geographic News
October 26, 2005
Researchers have built one of the world's smallest controllable robots—a machine tinier than the period that ends this sentence.

The miniscule device is as narrow as a human hair. Its inventors note that some 200 of them could line up across the top of an M&M candy.

A lab headed by Bruce Donald, a computer science professor at Dartmouth College in Hanover, New Hampshire, designed the robot. It was unveiled earlier this month at the 12th International Symposium of Robotics Research in San Francisco.

The machine can be steered anywhere on a specially designed surface. It moves with a wormlike crawl and turns by dragging a silicon "foot" around which it can pivot.

"Machines this small tend to stick to everything they touch, the way the sand sticks to your feet after a day at the beach," said Craig McGray, who earned a Ph.D. in computer science working on the robot.

"So we built these microrobots without any wheels or hinged joints, which must slide smoothly on their bearings. Instead these robots move by bending their bodies like caterpillars."

Small But Fast

A special floor provides a power signal to the robot anywhere on its surface, like a bumper car at an amusement park. Embedded in that power signal are instructions that the robot interprets, determining whether to go forward or to turn.

The machine can take thousands of "steps" per second, though each step is a tiny 10 nanometers (a nanometer is one billionth of a meter). It is tireless and, for its size, amazingly fast.

In half an hour, the robot can cover a foot (a third of a meter) in some 35 million steps. For a human, a proportionately similar stroll would lead half way around the world.

"Cleary it's a really neat thing to have done," said Kristofer Pister, a professor in the University of California at Berkeley's Robotics and Intelligent Machines Laboratory.

"There is a whole community of researchers that has been trying to get things to move around at the sub-millimeter scale, and [the robot's designers] have succeeded in one aspect of that far better than anyone else has."

Pister notes that microrobots at this scale currently depend on much larger support apparatus, like the specially designed floor.

In the future, he'd like to see them function on their own—and also pack a more technologically sophisticated punch.

"I don't know that any real robotics person would consider [a robot] something without built-in electronics or intelligence."

Tiny Robots, Enormous Possibilities

Though in their infancy, such tiny robots could someday be enormously useful.

Chris Levey, director of the microengineering lab at Dartmouth's Thayer School of Engineering, likens the possibilities to those of computer chips. As chips become ever more powerful, their many transistors working together can perform tasks far more complex than chips with only a few transistors.

"Part of the goal is that if we could make robots very small, in the future we can imagine many such robots interacting with each other and also interacting with very small things," he explained.

"Imagine this as a model of planetary exploration," McGray said. "You don't drop one Mars Rover, you drop a handful of dust which contains a million microscopic Mars Rovers that could explore the surface in a massively parallel way."

More earthbound applications may be closer to fruition.

One possibility is a "microfactory" in which the assembly floor serves as the robots' special power-supplying surface. Such a system could sprinkle minute parts onto the floor, where a team of microrobots assembles them into other tiny machines.

The robots could be of similar use in a microchemistry lab, where they might help regulate chemical processes by opening and closing valves.

The tiny machines could also be useful for information security, providing mechanical verifications inside computer systems. Other possibilities include work in hazardous environments or even within human cells.

"It's not impossible to think about them someday manipulating cells," Levey said.

Shrinking robots is a growing field of research. For that reason much of Dartmouth's microrobots' design will be in the public domain.

Far from guarding proprietary secrets, McGray hopes that others will be intrigued enough take the concept to another level.

"Will other people continue to explore the possibilities [this robot] raises?" he said. "That's how you get to useful applications. It's an incremental process."

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