Aerodynamic elegance Tiny flying robots the future of espionage

Sunday, July 28, 2002

BERKELEY, Calif. -- Understanding the aerodynamics that allow insects and hummingbirds to fly is the key to an invention that researchers hope will create a little buzz and a lot of flap.

Biologists and technologists at the University of California, Berkeley have spent the past four years developing a tiny robot, called the Micromechanical Flying Insect, that they say will one day fly like a fly.

The Berkeley project is among a handful aiming to engineer devices that can soar, dart and hover on gossamer wings that flap with a rhythm and precision otherwise found only in nature.

The projects are taking different paths, but the goal is the same: churn out tiny, nimble devices that can surreptitiously spy on enemy troops, explore the surface of Mars or safely monitor dangerous chemical spills.

The Pentagon's Defense Advanced Research Projects Agency is funding much of the work because of its potential application in both reconnaissance and surveillance.

In recent years, scientists at Berkeley and elsewhere have made huge strides in understanding insect and bird flight.

Their challenge is now to apply that knowledge to the design of devices that, at least at Berkeley, mimic the size, weight, power and -- above all -- aerodynamic elegance of a fly.

"What we're targeting is the blowfly, how it specs out," said Tim Sands, a professor of materials science and engineering.

Insects vs. jets

Lest anyone scoff, Sands and his colleagues point out that a fly can lift its own weight, turn more quickly than any fighter jet, zip about even on torn wings -- and cap it all off by landing on the ceiling.

"Insects," said Berkeley's Ron Fearing, "have tremendous maneuverability."

In a cluttered campus lab, the professor of electrical engineering and computer sciences uses tweezers to pick up a prototype of the mechanical insect. The robot is a flyweight contender for the title of most ambitious of all the flapping robots, generically called ornithopters, entomopters or micro air vehicles.

It has yet to fly.

The Berkeley device is being developed under a five-year, roughly $2.5 million contract. That's pricey for something best described in pocket-change terms.

It takes about a dime's worth of raw materials to build one of the robots. A single penny weighs more than two dozen of the devices. And each boasts a wingspan that matches the diameter of a quarter.

Officials envision soldiers deploying the robotic insects in battle, using them to snoop as only a fly on the wall can.

"It takes an individual and extends their sensory capabilities -- like a periscope -- but it flies independently," said Roy Kornbluh, an engineer at SRI International in Menlo Park. Along with DARPA, the firm has funded development at the University of Toronto of another flapper, a four-winged robot called "Mentor."

During a February flight, the device became the first ornithopter to hover, doing so with the agility of a hummingbird. Mentor is about one foot across and weighs one pound; researchers hope eventually to shrink it down to hummingbird size and weight.

As difficult as flapping flight is to ace, researchers remain enchanted by it because it makes for miniature flying machines that don't gobble large amounts of power.

"Flapping is much more aerodynamically efficient at small sizes," said Michael Dickinson, a professor of integrative biology at Berkeley.

"The good news is we know what the wings need to do. The bad news is we don't know how to do it," Fearing said.

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