Even going as far back as bird-like dinosaurs, ornithological animals have always benefited from folding their wings during upstroke. This makes birds an interesting inspiration for the development of drones. However, determining which flapping strategy is best requires aerodynamic studies. So, a Swedish-Swiss research team has constructed a robotic wing that can flap like a bird.
“We have built a robot wing that can flap more like a bird than previous robots, but also flap in way that birds cannot do,” said Christoffer Johansson, Lund University. “By measuring the performance of the wing in our wind tunnel, we have studied how different ways of achieving the wing upstroke affect force and energy in flight.”
Prior research has shown that birds flap their wings more horizontally when flying slowly. This new study shows that birds most likely do it — despite it requiring more energy — because it’s easier to create a sufficiently large force to stay aloft and propel themselves. Drones can emulate this to increase their range of speeds.
“The new robotic wing can be used to answer questions about bird flight that would be impossible simply by observing flying birds,” explained Johansson. “Research into the flight ability of living birds is limited to the flapping movement that the bird actually uses.”
The research explains why birds flap the way they do, via finding out which movement patterns create the most force and are the most efficient. The results can also be used to better understand how the migration of birds is affected by climate change and access to food, as well as many potential uses for drones.
“Flapping drones could be used for deliveries, but they would need to be efficient enough and able to lift the extra weight this entails,” said Johansson. “How the wings move is of great importance for performance, so this is where our research could come in handy.”