US

Researchers from University of Southampton and Imperial College London in the UK have developed new prototype bat wings that can be used in future unmanned micro air vehicles (MAVs).

The new membrane wings prototype has the ability to fly over long distances, change shape and can respond to any forces it encounters.

Developers of the design said the wings work like artificial muscles with the help of electro-active polymers infused in it.

Electro-active polymers make the wings stiffen and relax in response to an applied voltage. By changing the voltage, the shape of the electro-active membrane and aerodynamic characteristics can be adjusted during flight.

The wings have no mechanical components, a feature that makes them cheaper and easier to maintain than the usual wings.

The prototype was recently tested in-flight through a mix of experimental work at the University of Southampton and computational research at Imperial College London, with funding from the Engineering and Physical Sciences Research Council (EPSRC).

The US Air Force also extended additional support to the initiative.

Measuring as small as 15cm, the usage of MAVs are growing in civil and military applications, including surveying remote and dangerous areas.

"The prototype wing we have developed could enable a MAV to constantly adapt to their environment in real-time."

In order to fast track the design process, the Imperial team built new computational models and used them to help build a test MAV and integrated the bat wings.

The team from Southampton used these findings for a test vehicle, which is 0.5m-wide and can skim over the sea’s surface and, if required, land safely.

The vehicle underwent extensive wind tunnel testing.

University of Southampton aerodynamics and flight mechanics group professor Bharath Ganapathisubramani said: "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.

"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."

The Southampton-Imperial team is planning to integrate the prototype wings into traditional MAV designs, and is expecting to use the technology in commercial applications in five years.

Imperial College London department of aeronautics professor Rafael Palacios said: "Nature is a great source of inspiration for us when it comes to making improvements to MAVs.

"A bat’s ability to expand and compress its wing structure in order to deal with the changing nature of the environment is a particularly useful feature to mimic.

"The prototype wing we have developed could enable a MAV to constantly adapt to their environment in real-time.

"This ability to reconfigure would also allow multiple missions to be carried out using the same MAV, instead of us having to develop a totally new craft every time it needs to do a new type of task."

Image: Bat flight inspired design for micro air vehicle. Photo: courtesy of University of Southampton.