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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Taking a Page From the Book of Flight
27 November 2007 (All day)
Researchers have used a computer program that simulates avian evolution to design a better flying machine. With further refinements, the contraption's offspring someday might flit like bats or birds.
For centuries, scientists and inventors have been attempting--nearly always unsuccessfully--to adapt the graceful beatings of a bird's wings for mechanical flight. A flapping craft would have two main advantages over planes and helicopters: It could stay airborne over a wide range of speeds and would be more maneuverable, achieving both without sacrificing aerodynamic efficiency. Such abilities could be particularly useful for unmanned aerial vehicles (UAVs), the lightweight aircraft the military increasingly employs for low-altitude reconnaissance.
Researchers from Pierre and Marie Curie University in Paris embarked on a unique strategy to apply the secrets of bird flight. They created a program called an evolutionary algorithm that essentially "evolves" a birdlike creature from scratch, refining designs that work and tossing those that don't. The team then appropriated the most successful designs from the algorithm to create a simulated UAV. The simulation achieved a birdlike energy efficiency flying at speeds between 10 meters and 12 meters per second, the researchers report in the December issue of Bioinspiration and Biomimetics. Based on the tests, the team has built a mechanical prototype with the goal, says biologist and lead author Emmanuel de Margerie, of improving wing designs based on further refinements from the algorithm.
Evolutionary roboticist Inman Harvey of the University of Sussex, U.K., praises the team's artificial evolution approach. It allows the exploration of designs "that a human designer might not have considered venturing into," he says. Still, the team's findings are limited, says research engineer Robert Michelson of the Georgia Institute of Technology in Atlanta. He notes, for example, that the simulated UAV the researchers developed is only efficient at relatively high speeds; at lower speeds, flight efficiency drops dramatically. And despite its advantages, flapping flight has its share of kinks. The bouncing reduces the value of the craft as a camera platform, says Michelson, and flapping can place large strains on wings. So far, these "have been the long poles in the creation of flapping-wing micro air vehicles," he says.