Flapping NAV Performs Controlled Hovering Flight

An anonymous reader writes "AeroVironment, Inc. was awarded a Phase II contract extension in April from the Defense Advanced Research Projects Agency (DARPA) to design and build a flying prototype for the Nano Air Vehicle (NAV) program. As part of this program AV has accomplished a technical milestone never before achieved: the controlled hovering flight of an air vehicle system with two flapping wings (video) that carries its own energy source and uses only the flapping wings for propulsion and control. Two wings for propulsion and control, nothing else."

Comments

Apparently...

[d474]

...their website is being served off of the flapping bird robot, and said robot has crashed.

They can make flapping wing flying robots, but can't make a slashdot proof webserver, meh.

Slashdotted!!

[anonymousNR]

here's a link to another article which atleast has a computer generated image

Re:Ouch

[CorporateSuit]

Well, if everyone in slashdot was like me, we all wanted to see if it flaps like a vulture or like a hummingbird before posting...

Ornithopter

[fiannaFailMan]

Shouldn't this sort of thing be called an Ornithopter?

Re:Ornithopter

[metaforest]

"Nope. As you can see, the wings flap horizontally, which means it is a completely different concept, from what birds do."

You obviously have never taken a really close look at a slow motion video of a hummingbird doing the stationkeeping thing.
The NAV is mimicking a simplification of the hummingbird's vertical stationkeeping fight mode.

    Head, Tail and back are in a vertical orientation, (like a person standing) wings flapping in a 'sculling' motion to direct thrust downward. The wing shape is used more like a propeller blade in this mode than a lifting wing.

If you tread water, while swimming using arm-sculling, your arms are doing a slow motion version of roughly the same motions, with corrections, and for the same reasons, to maintain balance and position. Take particular note of how the hands are used as blades and tilted to direct force down against the water.
Our arm geometry is somewhat different so we don't orient the hand portion or our 'wing' vertically, and lacking feathers we rotate the thumb down to generate lift on the return stroke, rather than up and out as the hummingbird does.

The only difference with the NAV is that it's wing geometry is not as complex as a hummingbird so the system cannot switch to the more efficient horizontal orientation for cruising flight, the mode most birds use commonly. Hummingbirds use this more typical flight mode when they are not hovering.

I have witnessed some types of sparrows kind of manage the vertical flight mode, but their body's are not balanced correctly to make it very stable IMO. Consequently, they must use a lot more energy to stabilize the maneuver. This reduces their ability to hover to a matter of ten seconds or so before fatigue sets in.

Larger birds cannot mange the vertical flight mode at all. They simply can't move their wings fast enough to generate stable raw lift when their bodies are oriented vertically. The closest they can get is a cupped wing geometry used for VTOL maneuvers, and this too uses a lot of energy and is not stable enough for hovering.

One other variation I have seen is in small hawks where they seem to induce a low-speed stall and use small wing movements at the "wrist joint" to hold position for a few moments before committing to an attack dive. This is not a stable flight mode. After a few seconds they must either resume forward motion and normal flight, to mitigate the effects of the stall, or begin their attack dive.

Youtube

[reg106]

Here is an AeroVironment NAV video on YouTube. Not sure if it's the same one, but it was uploaded today...

When can I buy a ridable griffon/dragon?

[seanalltogether]

Dear engineering community, that's all I've ever wanted from you in life, please make it happen.

Re:When can I buy a ridable griffon/dragon?

[CorporateSuit]

Sponsor a $20 Billion, tax-exempt contract for ridable, mechanical dragons/griffons that live entirely off large livestock and I'm sure you'll have them fleet-ready in 15 years (as long as PETA doesn't catch wind of it).

Re:Why the hell would you do that?

[dotancohen]

People can't drive cars so now we give the same people flying cars...

Flying cars? It's a nano flying vehicle, not a nanny flying vehicle.

Clocks

[the_Bionic_lemming]

This just in, Prototype lost to clock with bacteria digester system.

PETA responded with applause.

Re:Ouch

[dotancohen]

0 comments and it's already slashdotted.

What the hell is this? Who are all the noobs who went off to RTFA?!? Has /. been trolled?

I thought . . .

[arizwebfoot]

it was pretty cool.

There will be hummingbird looking things flying in and out of your nearest neighborhood crime syndicate office monitoring their activities.

Who needs wiretapping now?

Oh, and I think hummingbirds have prior art.

Re:Ouch

[dotancohen]

Well, if everyone in slashdot was like me, we all wanted to see if it flaps like a vulture or like a hummingbird before posting...

European vulture, or African?

Advantages vs. traditional rotating wing?

[dfay]

To any familiar with this company or this line of research in general:

What are the advantages of the ornithopter design over a traditional helicopter design? Why is DARPA interested?

Yes, I did read the article... and I understand what DARPA is interested in getting out of a small UAV that can hover. What I don't understand is why a normal helicopter design couldn't suit all of these needs better and cheaper.

Regardless of the answer, it's a very cool project. Obviously very worthwhile just from the point-of-view of the scientific and engineering advances.

Re:Advantages vs. traditional rotating wing?

[Dynedain]

Helicopters are LOUD

Winged vehicles can glide (among other things) making them far more stealthy in small forms.

Re:Advantages vs. traditional rotating wing?

[evilviper]

There aren't biological structures that can rotate infinitely, because biological mechanisms require plumbing (blood, etc.) and muscle attach points on both halves of the rotating structure.

You need to take a good long look at your own shoulders...

No, not really a free-rotating structure, but more than close enough to be re-purposed into driving a rotor or propeller.

Re:Advantages vs. traditional rotating wing?

[UncleTogie]

I'm not one to throw out the word "impossible" very quickly, since people who have used that word have been proven wrong so many times in the past. However, I read an argument back in...Jr. High?...that claimed that a truly rotational structure on a biological organism was at the very least highly improbable. There aren't biological structures that can rotate infinitely, because biological mechanisms require plumbing (blood, etc.) and muscle attach points on both halves of the rotating structure.

How far down the size scale are you looking?

Take a peek at this and see if it's what you're thinking of.

Re:Advantages vs. traditional rotating wing?

[socceroos]

Yeah, with that wing span it has more chance of winning the lottery than gliding...

Re:wind gusts (argh... formatting)

[oodaloop]

The part that got me was 10 meters per second. That seems pretty damn fast to me for something that small that beats its wings.

WowWee's Bat and Dragon also hover on wings.

[Animats]

This is almost as good as WowWee's Bat and Dragon. They're little, they fly with moving wings, and they can hover. $39.99. Available wherever toys are sold. That's the entry-level product; the next step up, the Green Dragonfly, is an indoor/outdoor R/C ornithopter capable of hovering.

Those models doesn't have any onboard intelligence, but some of the other WowWee flying machines have collision avoidance. WowWee has a whole line of flying and robotic toys, and they deliver impressive technology at prices well under $100. Maybe DARPA should outsource.

Re:WowWee's Bat and Dragon also hover on wings.

[bughunter]

"Almost as good?" Hardly. The WowWee toys fly with moving wings, yes, but they're more glider than ornithopter, and require a rudder. The Aerovironment NAV is a true ornithopter, the flapping movement of its wings provides all lift and thrust and 3-axis control. But because this is slashdot, you're excused for opining out of ignorance, even when it could be cured by RTFA.

Re:wind gusts (argh... formatting)

[maxume]

It depends on what withstand means. I've watched lots of dragonflies (and other insects) fly around in stronger winds than that, gusts too. If they mean stay in the air and mostly on course, it should at least be possible, if they mean stay in one place, probably not.

Re:wind gusts (argh... formatting)(2x argh...typo)

[OeLeWaPpErKe]

Still it's quite impressive what they have today. "Withstand 2.5 m/s wind gusts" does not mean their ornithopter explodes if the wind exceeds that. It just means that above 2.5 m/s it will have to "go with the flow", and thus will lose a part of it's mobility. It can still control it's speed in 3 other directions though.

I have the impression that birds regularly hit this limit. They try to go against the wind, and it proves too much for them. They simply land and try again 5 seconds later, which usually succeeds.

So the 2.5 m/s wind limit could be quite acceptable, even for outdoor flight. Assuming it can land like a bird (ie. everywhere).

I do see one big problem these devices will have to contend with : Cats (perhaps not the lolcat variant, the regular one). So if you want to secure your house from these spying devices ... buy a cat. Birds, after 3 million years of evolution still haven't quite figured out how to protect themselves against cats, so it seems unlikely these guys will find it in the next month.