Move over drones, bat-inspired micro air vehicles coming soon

Inspired by bats, a team led by an Indian-origin researcher has successfully tested unique membrane wings that work like artificial muscles in flight, paving the way for a new breed of unmanned micro air vehicles (MAVs).

Bat-flight inspired MAVs will have improved aerodynamic properties, can fly over long distances and are more economical to run, said the team from University of Southampton and Imperial College London.

The wings change shape like bats in response to the forces they experience and have no mechanical parts - making MAVs incorporating them easier to maintain.

"We have successfully demonstrated the fundamental feasibility of MAVs incorporating wings that respond to their environment, just like those of the bats that have fuelled our thinking," said professor Bharath Ganapathisubramani from University of Southampton's aerodynamics and flight mechanics group.

"We have also shown in laboratory trials that active wings can dramatically alter the performance. The combined computational and experimental approach that characterised the project is unique in the field of bio-inspired MAV design," he explained.

The unique design of the wings incorporates electro-active polymers that make the wings stiffen and relax in response to an applied voltage and further enhances their performance.

By changing the voltage input, the shape of the electroactive membrane and, therefore, aerodynamic characteristics can be altered during flight.

The proof-of-concept wing will eventually enable flight over much longer distances than currently possible.

"No one has tried to simulate the in-flight behaviour of actuated bat-like wings before. We had to make sure it could model not only the wings themselves but also the aerodynamic flows around them and the effect of the electric field generated across them," noted Dr Rafael Palacios from Imperial's department of aeronautics.

Sometimes as small as 15cm across, MAVs are increasingly used in a wide variety of civil and military applications such as surveying remote and dangerous areas.

One emerging trend among MAV developers is to draw inspiration from the natural world to design vehicles that can achieve better flight performance and that offer similar levels of controllability to small drones but use the efficiency provided by wings to fly much further.

The next step is to incorporate the active wings into typical MAV designs, with deployment in real-world applications potentially achievable over the next five years.

The team received funding from the Engineering and Physical Sciences Research Council (EPSRC) and the United States Air Force provided additional support.