Drones

Hovering kestrel inspires drone that gains altitude without using power

Hovering kestrel inspires dron...
The team has previously explored the kestrel's ability to detect and make use of surrounding wind currents as a means of countering turbulence
The team has previously explored the kestrel's ability to detect and make use of surrounding wind currents as a means of countering turbulence
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The team has previously explored the kestrel's ability to detect and make use of surrounding wind currents as a means of countering turbulence
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The team has previously explored the kestrel's ability to detect and make use of surrounding wind currents as a means of countering turbulence

A near-future where the skies are filled with drones carrying out deliveries and surveillance might be hard to imagine, but it is something aerospace experts are already giving careful consideration to. Improving the efficiency of these vehicles, even at the margins, could mean huge energy savings and more reliable services across the board. To this end, Australian researchers have developed a fixed-wing aircraft that uses natural updrafts to climb higher, inspired by the ability of the kestrel falcon to hover while searching for prey on the ground.

The UAS (Unmanned Aircraft Aystem) Research Team at Melbourne's RMIT University has been studying nature as a means of improving aircraft performance for some time. It examines how birds like the kestrel use sensory information gathered through its feathers to make small adjustments to its wings and tail, allowing it to lock its head into position and keep its eyes stable while its scans the ground for prey, all without flapping its wings.

In its earlier work, the team has explored the kestrel's ability to detect and make use of surrounding wind currents as a means of countering turbulence. Its latest advance, however, has enabled a gliding aircraft that can not only maintain its altitude, but climb even higher without drawing on extra power.

"It's long been known the birds take advantage of upward air currents to save energy when flying," explains Alex Fisher, lead author of the research paper. "This 'boost' of upward-moving air can be found when the wind hits a large obstacle, like a cliff or mountain range, and to a smaller extent close to man-made obstacles like buildings."

The researchers fitted a commercially available polystyrene sail-plane with GPS, a magnetometer and a control board with a purpose-built control algorithm. They then turned to the field in search of natural upward drafts, choosing a hillside and a space alongside a building as their two test sites.

At the hillside, the researchers found the aircraft was able to gain around 360 ft (120 m) in altitude unpowered, flying autonomously until its control batteries lost power. The tests at a building site were less fruitful, with the aircraft only able to sustain flight for around 20 seconds due to long-lasting gusts and lulls in wind.

The researchers say there are lessons to be learnt from this second exercise, however. As birds are able to accomodate such fluctuations in wind patterns by changing the arrangement of their feathers and adjusting their wings, the researchers are now looking to mimic this process in pursuit of an aircraft with similar capabilities.

The research was published this month in the journal Bioinspiration & Biomimetics.

Source: IOP

5 comments
Mel Tisdale
I suppose we will need a whole new suite of 'rules of the road' the most urgent of which would seem to be those governing 'power gives way to sail' situations.
Nik
Why not just train a bird, maybe a kestrel?
Druid
Boring. So they have an algorithm that senses lift. Gee works fine in ridge soaring. Mission crit' work means no loitering for altitude gains in thermals.
vblancer
As to Mel Tisdale's comment about "new rules of the rode" this is not the case. They already exist. When I was a student pilot we were constantly operating in the same airspace as the Goodyear Blimp and gliders in SoCal. All powered aircraft had to give the blimp right of way. Same for gliders there is a list of who has to give way to whom as it only makes sense a powered craft must give right away to unpowered aircraft.
So who was at the top of the list? Balloons! We all had to gave right of way to balloons. Every student pilot in the U.S. has to learn this list and it can be part of not only your written test but in my case it was even part of my "FAA Practical Test" or as we called it the Check Ride as I was in the airspace with the blimp during my test!
DomainRider
We know what a kestrel looks like; so what about a picture of the subject of the article?