TimmyHRobot Dragonflies - A New Weapon?
June 12th 2008 08:05
The U.S. military hopes one day to be able to use tiny flying robots for surveillance. The robots would come fully equipped with cameras, sensors and navigation equipment. They would also be able to fly long distances without any need to re-fuel or even stop.
A group of researchers at the University of Ulm in Germany have combined with scientists from the Royal Veterinary College in Britain to investigate the possibility of using dragonflies as part of a new study into tiny robot design.
Dragonflies are rare in that they are able to utilise four independently controlled wings to fly, this allows them to hover, dart, glide, move backward, and change directions rapidly.
The researchers have developed a robotic dragonfly to measure the air flows over and under the wings at different flap cycles. The team found that if the lower wings beat slightly ahead of the top wings 22 percent less power is required to lift the same weight as a single pair.
“The one specific advantage you get in four wings is the manoeuvrability and ability to pick things out of the air and hover and dart around,” says Jonathon How, an MIT expect in small robotics. “It would be really amazing if we could build something that got anywhere near that level of performance. If you can achieve the same lift at a lower power, that's helpful.”
The complexity of the robotics involved has mean that no working prototype has yet been produced. Also, the materials do not yet exist for small robotics to be so intricate and efficient in flight.
The Ulm researchers immersed their robotic dragonfly in a tank filled with mineral oil and peppered with air bubbles to work out flows over the wings. Two green lasers were used to reflect light off the air bubbles. By comparing detailed images, the scientists calculated the direction of flow for regions within the tank.
“It's a trade-off," says Fritz-Olaf Lehmann a researcher at the University of Ulm. The four wing system requires more power and incredibly advanced control systems but does not require physical changes to the wings in order to alter lift and change direction. “You can just advance one flight system against the other, and then you change lift production,” says Lehmann. “I think that makes building a micro air vehicle much easier.”
Professor Robert Wood, of Harvard University says when it comes to efficiency, in flight, “every little bit counts. You could make the argument that if you have a four-winged vehicle, you'll have more control to assist you in stabilization.”
But in order for the technology to be successful, researchers must still develop a better lighter battery that powers the vehicle and makes an effective control system.
A group of researchers at the University of Ulm in Germany have combined with scientists from the Royal Veterinary College in Britain to investigate the possibility of using dragonflies as part of a new study into tiny robot design.
Dragonflies are rare in that they are able to utilise four independently controlled wings to fly, this allows them to hover, dart, glide, move backward, and change directions rapidly.
The Ulm Robotic Dragonfly
The researchers have developed a robotic dragonfly to measure the air flows over and under the wings at different flap cycles. The team found that if the lower wings beat slightly ahead of the top wings 22 percent less power is required to lift the same weight as a single pair.
“The one specific advantage you get in four wings is the manoeuvrability and ability to pick things out of the air and hover and dart around,” says Jonathon How, an MIT expect in small robotics. “It would be really amazing if we could build something that got anywhere near that level of performance. If you can achieve the same lift at a lower power, that's helpful.”
The Ulm researchers immersed their robotic dragonfly in a tank filled with mineral oil and peppered with air bubbles to work out flows over the wings. Two green lasers were used to reflect light off the air bubbles. By comparing detailed images, the scientists calculated the direction of flow for regions within the tank.
“It's a trade-off," says Fritz-Olaf Lehmann a researcher at the University of Ulm. The four wing system requires more power and incredibly advanced control systems but does not require physical changes to the wings in order to alter lift and change direction. “You can just advance one flight system against the other, and then you change lift production,” says Lehmann. “I think that makes building a micro air vehicle much easier.”
Professor Robert Wood, of Harvard University says when it comes to efficiency, in flight, “every little bit counts. You could make the argument that if you have a four-winged vehicle, you'll have more control to assist you in stabilization.”
But in order for the technology to be successful, researchers must still develop a better lighter battery that powers the vehicle and makes an effective control system.
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