If we put pigeon feathers on a drone fly like a real bird?
I guess at some point that question went through the head of David Lentink, from Stanford University in California, who with his team has designed a robot that looks like a pigeon and can make sharp turns like real birds, something that could be an important step in aerospace engineering.
The individual wings are made up of multiple feathers that interact with each other, allowing the bird's wings to continuously transform mid-flight. Scientists first looked at the wing of a pigeon carcass: each wing had 40 feathers, 20 on top and 20 on the bottom, and began to work.
They put a marker on each individual wing and measured the relationship between the movement of the feathers and the movement of the bones. In doing so they discovered that the angle of the joint determined the angles of all flight feathers at any time, meaning that birds can change the shape of their wings without having to control each individual feather. This reduces the number of variables, or degrees of freedom, required to model the wings.
The team put this new find into practice at the PigeonBot building, an attempt to recreate the flight of the pigeons. It is powered by a propeller and has wrist and feather joints on each wing that can be controlled remotely. Its average speed is approximately 40 kilometers per hour, which is slightly slower than the average pigeon.
Lentink and colleagues also discovered that this type of flight was only possible due to certain molecules embedded in the feathers. These molecules, which are only 10 microns wide, allow the feathers to move away from each other while ensuring that they do not separate too far. This in turn reduces the level of individual feather control required for precise flight.
PigeonBot also uses real pigeon feathers, because no synthetic material has this property.
You can see the design at robotics.sciencemag.org