Researchers at Stanford University have been looking into exactly how birds can maintain controlled flight by changing the shape of their wings. For their study, they invented a robot called PigeonBot that has a pair of “biohybrid morphing wings.” The robot is being used to test out new control principles. One of the most interesting aspects of the PigeonBot is that the scientists fitted the flying robot with real bird feathers.
The researchers have discovered that bird feathers stick to the adjacent feather to resist sliding in one direction, only using a micron-scale feature that researchers describe as “directional Velcro.” The team says that this is something that is “new to science and technology.” Real feathers can slide, allowing the wing to change shape, but past a certain point, the directional Velcro engages to keep gaps in the wing surface from developing.
The scientists also noted that the real bird feathers have other advantages in that they are softer, lighter, more robust, and are easy to get back into shape after a crash. The PigeonBot connected the real feathers elastically to a pair of robotic bird wings with wrist and finger joints that can be actuated individually. Rather than having flapping wings, the robot uses a traditional propeller and a conventional tail.
Researchers found that the roll of the PigeonBot could be controlled with movement of the finger joint on the wing alone. They say that this technique is inherently more stable than the aileron roll used by conventional aircraft.
The researchers believe that the directional Velcro discovery is one of the more important findings from their study. Surprisingly, they’re not pursuing any additional applications and have decided not to patent the finding so that their discovery can benefit society at large.