While it is understood that birds morph the shape of their wings to fly through the air, new pigeon wing studies reveal a simpler model for how bird flight really works. A team of engineers has created a nimble flying machine called PigeonBot that they hope will prove inspirational for people studying birds or aviation.
Using motion-capture, Laura Matloff, a Stanford University student, was researching how feathers work. Interested in incorporating biology into engineering, she took measurements on how feathers and bones move together. David Lentink, the corresponding author and an assistant professor of mechanical engineering, commented that they used cadavers of museum birds to avoid causing harm to live birds.
The team soon discovered that pigeon wings are not so complicated and rely on two basic variables: the angle of the finger joint in the middle of the wing and the overall wing angle. With this knowledge, they created a model of pigeon flight where a flexible rubber band alters the angle of the feathers in unison.
To understand how the feathers stay locked during flight, the scientists used electron microscopes and CT scanners, discovering a Velcro-like system of hooks and barbs that activates when a wing spreads. This “directional Velcro” proved to easily withstand strong winds, and the discovery was published in the Science journal.
Meanwhile, Stanford graduate Eric Chang was also studying flying creatures and investing time in competitive small aircraft designs. With his experience, two decades of bird-inspired knowledge, and Matloff’s research, his team attached forty real pigeon feathers on an artificial skeleton. It could move at the base and the finger joint, using rubber bands to control the angle of the feathers. The robot bird also received an artificial tail, rudder, controllers, propeller, and sensors. It was tested in a wind tunnel and in an outdoor environment.
Eventually, the robot bird flew successfully, and Lentink saw many applications for the research, including the development of new kinds of Velcro, flight models, and bird studies. The researchers now look forward to continuing their studies, taking more measurements, and improving the PigeonBot.