The membrane wings work like artificial muscles in a similar fashion to bats. Picture credit: University of Southampton

Micro air vehicles with no mechanical parts inspired by bats

A new breed of unmanned micro air vehicles (MAVs) takes inspiration from the wings of bats in order to improve their aerodynamic properties so they can fly over long distances and are more economical to run.

The wings change shape in response to the forces they experience in the air by incorporating electro-active polymers that make them stiffen and relax in response to an applied voltage.

The membrane wings work like artificial muscles, moving in a similar fashion to those of bats, which are the only type of mammal that is naturally capable of flight.

The MAVs are being developed in a joint research project between the University of Southampton and Imperial College London which built computational models based on bat flight and used them to aid in the construction of the prototype device.

The system allows the vehicles to forgo mechanical parts which make them easier to maintain than other miniature flying vehicles of their type.

By changing the voltage input, the shape of the electro-active 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.

MAVs offer similar levels of controllability to small drones, but use the efficiency provided by wings to fly much further.

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

“This is a paradigm shift in the approach to MAV design,” said Dr Rafael Palacios from Imperial College London.

“Instead of a traditional approach of scaling down existing aircraft design methods, we constantly change the membrane shape under varying wind conditions to optimise its aerodynamic performance.”

Professor Bharath Ganapathisubramani, who is leading the project, said: “We’ve 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.

“We’ve 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.”

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

The project is not the first time that scientists have taken inspiration from nature for technological purposes.

Yesterday, is was revealed by the University of Bristol that shrimps could unlock the key to improved polarisers, optical devices that are widely used in cameras, DVD players and sunglasses.

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