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Dragonfly or Insect Spy? Scientists at Work on Robobugs.
VIDEOS | 'The Dragonfly'
Robotic fliers have been used by the military since World War II, but in the past decade their numbers and level of sophistication have increased enormously. Defense Department documents describe nearly 100 different models in use today, some as tiny as birds, and some the size of small planes.
All told, the nation's fleet of flying robots logged more than 160,000 flight hours last year -- a more than fourfold increase since 2003. A recent report by the U.S. Army Command and General Staff College warned that if traffic rules are not clarified soon, the glut of unmanned vehicles "could render military airspace chaotic and potentially dangerous."
But getting from bird size to bug size is not a simple matter of making everything smaller.
"You can't make a conventional robot of metal and ball bearings and just shrink the design down," said Ronald Fearing, a roboticist at the University of California at Berkeley. For one thing, the rules of aerodynamics change at very tiny scales and require wings that flap in precise ways -- a huge engineering challenge.
Only recently have scientists come to understand how insects fly -- a biomechanical feat that, despite the evidence before scientists' eyes, was for decades deemed "theoretically impossible." Just last month, researchers at Cornell University published a physics paper clarifying how dragonflies adjust the relative motions of their front and rear wings to save energy while hovering.
That kind of finding is important to roboticists because flapping fliers tend to be energy hogs, and batteries are heavy.
The CIA was among the earliest to tackle the problem. The "insectothopter," developed by the agency's Office of Research and Development 30 years ago, looked just like a dragonfly and contained a tiny gasoline engine to make the four wings flap. It flew but was ultimately declared a failure because it could not handle crosswinds.
Agency spokesman George Little said he could not talk about what the CIA may have done since then. The Office of the Director of National Intelligence, the Department of Homeland Security and the Secret Service also declined to discuss the topic.
Only the FBI offered a declarative denial. "We don't have anything like that," a spokesman said.
The Defense Department is trying, though.
In one approach, researchers funded by the Defense Advanced Research Projects Agency (DARPA) are inserting computer chips into moth pupae -- the intermediate stage between a caterpillar and a flying adult -- and hatching them into healthy "cyborg moths."
The Hybrid Insect Micro-Electro-Mechanical Systems project aims to create literal shutterbugs -- camera-toting insects whose nerves have grown into their internal silicon chip so that wranglers can control their activities. DARPA researchers are also raising cyborg beetles with power for various instruments to be generated by their muscles.