Bird-inspired drones to stay airborne longer

Drones have become increasingly affordable and accessible to more and more people over the years. Their reduced size has also made it possible for these Unmanned aerial vehicle’s (UAV) to be used for new purposes that are not in principle suitable for larger drones.

The biggest problem with microdrones remains the same… It is the short amount of time they can be kept in the air by their small batteries as well as the low stability they have in the face of turbulence that other objects flying nearby can cause.

Thanks to this new discovery, this may soon change. In a paper published in the journal Science Robots, researchers from Brown University (Rhode Island, USA) and the EPFL (Federal Polytechnic School of Lausanne, Switzerland) have presented a new design for drone wings that would be capable of offering a flight range of almost 3 hours, four times longer than similar drones with conventional wings. These new air vehicles would weigh only 100 grams.

To create this new design, researchers have simply limited themselves to watching birds and some insects and their way of flying. It seems that conventional lift surfaces work best when there is a flow of air that sticks to the wing over as much of the surface as possible. If the flow on an aerodynamic surface becomes separated from the wing surface, this can cause high turbulence and loss of lift or control. However, for many large insects and birds, flow separation is the basis of how they move.

"Small-scale drones have sufficient detection and computing power for an increasing number of applications. However, flying in Reynolds' low-number regime remains a challenge. High sensitivity to atmospheric turbulence compromises the stability and control of the vehicle and low aerodynamic efficiency limits flight duration," the researchers explain.

"Conventional wing designs have so far failed to address these two shortcomings simultaneously. Here we took inspiration from nature's small fliers to design a wing that generates robust lift in gusts and free-flowing turbulence without sacrificing aerodynamic efficiency," they add.

For now, the model has only been tested in a wind tunnel and is awaiting testing in a real environment. However, the team behind the design has patented it and intends to further improve it.

Recently, the PigeonBot, a new drone that carries up to 40 real bird feathers and is able to fold its wings, was also unveiled. The robot was designed by Stanford University and was another major discovery that could influence the design of UAVs in the future.

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