Everyone knows about the current rage for biomimetics - the building of machines or robots which copy design features from living creatures. But now a top UK biomech boffin has hurled cold water over the whole idea. "My work should act as a reminder to be cautious in copying nature," says Dr Jim Usherwood of the Royal Veterinary …
Biomimetics has indicated that certain natural aquatic modes of movement are more efficient than current tech. Think mechanical fishes on rails and sea gliders.
Natural flight may be rubbish, but we have at least investigated and found that out. Science isn't about only trying out things that work. It should find both things that work and things that don't.
Fairly obvious that natural structures are limited
The most efficient system for travel is the wheel, or some derivative thereof. You don't see too many animals scooting about on wheels, though.
Has this boffin figured in scale, though? Gravity and inertia become much less bothersome when you're a gnat, for example, compared to if you're an eagle. Ants have an awesome power to weight ratio, but if you scaled them up they'd be fairly crap. (Even if they didn't immediately expire from suffocation - let's ignore that for this example.)
Good macro-scale engineering may not be as effective at nano-scale. So trying to scale down macro stuff may not actually work that well.
Dr Jim sounds like a whiner. He can't get his experiments to work, therefore it is obviously impossible for anyone else.
"If you want to hover be a helicopter, not a flapper" - might be the silliest thing I've heard in a long time. Winged animals that can hover far outperform/out maneuver even the best helicopters, it's not about efficiency you fool.
On a related note: When's the last time you saw a dragonfly suddenly stop flying and fall from the sky. It's been a while for me but we had a helicopter fall out of the sky (no deaths) just this weekend.
......theres more to it than the article covers. Certainly a rotor is better for hovering than a beating wing, for exactly the reason you state. But nature does teach us in some areas. If you want to efficient _and_ quiet underwater then im sure the fishes could teach a thing or two. And all of these projects that try to mimic how snakes move will certainly work better on the red planet than our wheels do. So for the example chosen he is clearly right, but im not sure it can be applied globally.
Mimetic solutions are not just concerned with flight efficiency.
The problem with black helicopters is that they look like black helicopters.
Which isn't much use when you're using one as a fly-on-the-wall.
Also, a bot-brained bat is more useful than a bat-brained bot (try saying that on a Friday afternoon).
the artical is deceptive as it suggests that the bots are all being based around 'flapping' wings, this is not the case.
the majority of practical solutions are based around how birds/bats change their wing shape allowing tighter turns, better low speed lift and better aerodynamics at speed whist retaining conventional propulsion (propellor/jet).
nary a flap in sight.
"The most efficient system for travel is the wheel, or some derivative thereof"
LOL. Not in the bloody air it aint!
A bit of a nonsence
Most of the insects - at least the best flyers - do not flap wings.
There is no start-stop momentum involved - it's more like an "8"-shaped movement.
See eg http://www.biology-resources.com/images/wing-movements-big.jpg
It's been a couple of minutes since I read the article, but I'm fairly certain that at the beginning he suggests his work might act as a reminder to be catious about copying nature. I don't think, from this brief text, he was ruling out all aspects of every natural mechanism.
Also, my new favourite quote (for today at least): "Compared to ordinary aeroplanes, helicopters etc, birds, bats and insects are basically crap". I love that.
And I'd really like to see some wheeled animals. Can't we GM some?
Vulture - should've been a chopper!
Nothing to read here, move along
The good prof just wants to remind the world of his existence. Just a loser void of good ideas. Move along. Nothing of relevancy here.
Call again when you have a helicopter the size of a fly or mosquito with the same maneuverability and supplied by some grass juices or a drop of blood.
Re: Fairly obvious that natural structures are limited
"The most efficient system for travel is the wheel, or some derivative thereof. You don't see too many animals scooting about on wheels, though."
Hah! That's where you're wrong! I point you to the documentary "Chorlton and the Wheelies":
"(Usherwood's test pigeons apparently have to carry lead fishing weights to check their performance, and fly with reflective tape spots all over them so that their wing oscillations can be precisely monitored.)"
Does the RSPCA / RSPB know about this?
Yes, but the dragonfly ain't going to be in the air if it feels unwell. The chopper will ascend if all the instruments indicate that all is well, there are a wide variety of critical components that are not actively monitored (ground checks or service checks only) and proper component failure prediction is still on the nice idea list.
Your example doesn't indicate that the locomotion of the dragonfly is superior to that of the chopper. It does indicate that biological constructs are superior to mechanical ones when it comes to diagnostics.
Now, I for one have never seen a dragonfly gliding and I have no idea what the gliding characteristics of a suddenly flapless mechanical dragonfly are, but the known autorotation characteristics of the rotorcraft mean that I'd rather be sitting in that when the shit hits the fan.
I would tend to believe...
that's it's the power source, not the motion, that makes the Living versions of these bots so effecient.
Couple hours of flying on some sugar from a flower? Make a bot that can refuel like that, and you'd have a winner!
Turning flies into gliders...
"...I for one have never seen a dragonfly gliding and I have no idea what the gliding characteristics of a suddenly flapless mechanical dragonfly..."
Hairspray or spraymount... Never tried it on a dragonfly (I like dragonflies), but bluebottles don't glide worth a damn. "Not so much 'glide', as 'plummet," to paraphrase a sketch about animal locomotion.
Not that simple
Yes, flapping is not efficient but from the flexibility and multi-role applications it is by far the best solution.
Ever saw an Osprey transition to and from hover? It takes almost a minute (maybe more - I can't remember).
On the other hand, even the bloody pigeons can take off vertically (at least in London they can), transition to flight, then to glide, then land vertically again - all in a matter of seconds.
As someone already said above - the issue is in the power supply. Living things may not employ the most efficient flight mechanics but they can afford it because they have a high efficiency energy-to-work "solution".
Insect wings move up and down in a special way...
Small insects, such as mosquitos, beat their wings at very high frequencies (which is why they buzz at high frequency). If you cut off the ends of the wings, they will beat at an even higher frequency. This shows that the wings are beating like the tines of a tuning fork, i.e. they are vibrating. The energy to accelerate and decelerate the wings as they move up and down is not wasted but stored and released elastically.
The insect's flight muscles simple add the energy required to move the air to generate lift.
Small insects fly with amazing efficiency. Insects are regularly carried enormous distances (even across the Atlantic) by the wind, with the creature only having the consume minute amounts of food to stay aloft for a couple of days or so.
Of course, it is a matter of scale. If you increased the size of a mosquito to a 747 the natural frequency of vibration of the wing would be so low that no useful aerodynamic forces would be generated.
> And I'd really like to see some wheeled animals. Can't we GM some?
Efficiency vs Manoeuvrability
Research looking at changing wing shape has already been mentioned, but another important aspect of animal flight is instability: it's how bats turn so fast to catch their insect prey on the wing, for example. Bat flight may be very inefficient, but you don't see many gliders turning in their length to snap a gnat out of the air!
I think nature/natural selection has done a pretty good job. IIRC, an albatross can stay aloft for days and cover thousands of miles on a single journey, all on a stomach full of fish. My model aeroplanes, using propellors, hi-tech batteries and the things that the prof. thinks so superior, can stay up for about 20 minutes!
There was a good item that he probably missed on R4 recently, about the variable geometry of a Swift's wing, whereby it alters the shape and sweep to suit the conditions. This works so well that they can stay in the air (refuelling as they go) for two to three years...
Wheels are fine on smooth level surfaces, but anyone who has cycled up a steep hill will know the limitations. A friend of mine says that he will take robots seriously when they can successfully walk upstairs carrying a plate of soup. I agree.
lets take fuel out of this
I suggest we build a rig with flapping wings and one with fixed wings and/or helicopter designs. Then to decide which is better, we add a squirrel and a wheel to power it. This will take biological energy out of this. Also we'll need it to lift and power a camera and wireless, since I'm assuming this is for black ops anyways. Maybe we can use a mosquito with it's wings affixed to a solo-flex/generator for a nano version to test the nano thing out?
Boffin of Buffoon?
Animals are incredibly efficient at what they do and so copying their design features is generally a good idea. However, if you want to fly a few hundred people across the Atlantic, then an oversized pigeon is unlikely to be a good design. The first "workable flying machines" were created to carry humans. How may human sized birds has the prof seen flying about? Smaller payloads might actually benefit from simulating the flight of birds.
Animals are designed to grow, feed, hunt, reproduce, etc. If you take away the "life" aspects from an animal and just look at say, its method of propulsion, then you'll probably be able to improve on it. It's like saying that steel is a better building material than wood therefore trees are pretty crap.
Nature hasn't used the wheel much because the separation between wheel and axle means one element, e.g. the wheel (or rotor), has to be dead. So if you equip a large animal with wheels, how would the wheels grow as the animal grows? How would they repair themselves if damaged?
Like Pierre Castille above said;
It's the resonance!
Small birds and bats, and all flying insects beat their wings at a rate that resonates to their wings physiognomy. There is a push on the thrust producing down stroke, most of the rest of the motion is produced by elasticity in the tendons (and exoskeleton for insects).
So, once in flight, it takes a periodic pulse of muscle to maintain the harmonic motion of the wing stroke, unlike a rotary propeller, which needs a constant applied motion to maintain lift.
(Stupid analogy time: Compare the amount of energy needed to bounce a ball rapidly, with the amount needed to hold the ball and carry it up and down with muscle power the same distance and speed.)
Really, the good Doctor sounds like the Victorian scientists that maintained that bees were too heavy to fly, and dogs were only overheating themselves more by panting. We've learned a bit since then.
(Seriously, a pigeon attempting to fly with a load it isn't designed to carry is less efficient than an aircraft carrying a load it's designed for? To quote Paula Bean http://thedailywtf.com/Articles/The_Brillant_Paula_Bean.aspx , "Brillant!")
I chose the penguin, it's rather inefficient at flight too.
Kangaroos can't survive, either
There's no way a kangaroo can eat enough during a day to sustain their jumping up and down - it's obvious, constantly moving that mass up and down would use up more energy than they can consume in a day - they'd use more energy moving to a food source than they'd get from eating it.
Trust me on this, all the maths has been done.
>I chose the penguin, it's rather inefficient at flight too.
No its not... http://www.youtube.com/watch?v=pG5dzybHgTo
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