Nature’s Creatures Inspire Better Flying Vehicles
From falling geckoes and flying snakes to cruising seagulls, nature’s animals are teaching engineers how to design the next generation of flying vehicles. But instead of carrying humans, these next-generation soaring craft will carry sensors, cameras and microphones.
The way insects, bats and birds are able to maneuver in the air is amazing, and is unmatched by modern airplanes, said David Lentink, a professor at Wageningen University in the Netherlands and author of an editorial on the research published in the Nov. 24 issue of the journal Bioinspiration & Biomimetics.
For example, birds can change their wing shapes to affect and control their flight.
“If you think of an airplane, the best we can do is we have some flaps and slats that can be thrown out when an airplane has to land or take off,” Lentink told TechNewsDaily.“But a bird can dynamically adjust its wing shape continuously so if it wants to make a good turn then it fully spreads its wings and when it wants to fly fast it sweeps its wings backwards.”
Now engineers and biologists are developing tiny air vehicles based on the flying expertise of insects and birds . For example, one group at the University of Florida is taking the lead from seagulls with a micro-air vehicle that can change wing shape just like nature’s fliers.
Seagulls have a series of joints that allow them to alter the shape of their wings, giving them superior flying capability, especially for steep descents and travel in crosswinds.
The seagull-inspired micro-plane is made of carbon fiber with “elbow” and “wrist” joints to allow the plane to morph its wing shape depending on its environment and task. Measuring 18.9 inches (48 centimeters) long and weighing just 596 grams, the micro-air vehicle was able to “turn with significantly increased angles of attack and sideslip compared to traditional fixed-wing vehicles.”
While not really a flier, the tree-dwelling snake Chrysopelea paradisi can glide more than 80 feet at a time as it soars from tree to tree.
John Socha, a biologist at Virginia Tech, and his colleagues launched snakes from a 49-foot tower while videotaping the airborne creatures. By analyzing the videos, the team was able to explain the movements of the snakes’ bodies responsible for this magnificent air gliding.
“You can really see how nicely the snake is able to glide down to the ground,” Lentink said.“That could be interesting for a snake-like robot that goes places and then needs to get back to the ground.”
Scientists are also gleaning insights into safe landings from animals such as geckos. “The gecko rights itself like the falling cat, but using a completely different mechanism,” said study author Robert Full, a professor at the University of California,Berkeley. “The cat twists its body, whereas the gecko only swings its tail.”
Full and his colleagues used a gecko-like climbing robot equipped with a tail developed at Stanford University named Stickybotto investigate what would happen if a robot slipped during climbing.
“To our surprise, they use their tail as an emergency fifth leg to stop them from falling head over heels off the wall,” Full said. “We also discovered that they can glide and use their active tails to achieve turns.”
While not animals, maple seeds seem to have some tricks to simplify the design of micro- helicopter: They fall to the ground in a spiral motion.
“You could imagine if you put a small engine on [the maple seed] it might be able to spin up again,” Lentink said.
Researchers at the University of Maryland have done just that and developed a robotic maple seed that can hover, climb and fly in a forward direction.
Other leads from nature include the perfect hovering motion of the hummingbird , and insects with deformable and flapping wings. These bio-inspired findings will help to create cheaper, lighter-weight, and more effective micro-air vehicles.
“These are all examples of small micro-air vehicles that can really make a difference,” Lentink said, but added that “it will take a while before these ideas become commercially available.”