[HN Gopher] Bird-inspired drone uses legs to walk and jump into ...
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       Bird-inspired drone uses legs to walk and jump into the air
        
       Author : bookofjoe
       Score  : 180 points
       Date   : 2025-01-07 00:31 UTC (3 days ago)
        
 (HTM) web link (spectrum.ieee.org)
 (TXT) w3m dump (spectrum.ieee.org)
        
       | litenboll wrote:
       | First thought when reading the title was that it will look very
       | fragile and clumsy when walking (even real birds do) and that was
       | confirmed by the first video. What's the purpose of actually
       | mimicing bird legs and feet? Why not use something more simple
       | like wheels on a board that has a spring for example? I expected
       | the article to justify why, but to me it seems like the big thing
       | was the jumping itself, which does not require complex bird
       | anatomy necessarily. There's probably a good reason that I
       | missed, but this feels like a too direct translation of the bird
       | feature, unless the purpose is specifically to make it look and
       | move like a real bird.
        
         | pixxel wrote:
         | Spy drones than mimic birds.
        
           | 9dev wrote:
           | It's going to get interesting when the conspiracy theory
           | becomes reality. Imagine the future historians browsing the
           | Reddit archives going like, "they knew!!"
        
             | Super_Jambo wrote:
             | More likely that sensible mainstream journalists will laugh
             | at people under Govt surveillance because they sound like
             | the reddit conspiracy nuts from their youth...
        
             | oefrha wrote:
             | What conspiracy? CIA had spy pigeons among other animals
             | half a century ago, which is public info by now.[1]
             | 
             | They are very proud of it too.
             | 
             | > While many of the animal programs studied by CIA were
             | never deployed operationally--or failed for a variety of
             | technical, logistical, or behavioral reasons--collectively
             | they demonstrate the incredible innovation and creative
             | thinking that has come to characterize everything that our
             | Directorate of Science and Technology does.
             | 
             | [1] https://www.cia.gov/stories/story/natural-spies-
             | animals-in-e...
        
               | 0xEF wrote:
               | Every good conspiracy theory starts with a truth, I
               | guess.
               | 
               | I had no idea about the CIA thing. I just always assumed
               | the "birds aren't real" meme to be a way of showing how
               | ridiculous the police state is going to become in the
               | next decade or so as surveillance gets more and more
               | weaponized against the people it was supposed to protect.
        
               | butlike wrote:
               | I always took "birds aren't real" to be an absurdist take
               | on paranoia
        
             | JKCalhoun wrote:
             | Like the Chinese one?
             | 
             | https://interestingengineering.com/military/chinese-
             | special-...
        
             | mapt wrote:
             | Military contractors have been producing teaser videos on
             | the subject for maybe fifteen years now.
        
           | gattr wrote:
           | Makes you wonder what will come first:
           | 
           | - energy-efficient, long-lasting, mechanically optimized
           | robotic "birds"
           | 
           | - good-enough understanding of the avian brain connectome &
           | operation, such that all you need is a bunch of fine wires
           | stuck in it, and a small CPU sending commands (local and
           | remote operation, etc.)
        
           | Cthulhu_ wrote:
           | https://www.reddit.com/r/BirdsArentReal/
        
           | veunes wrote:
           | It's like the ultimate bio-inspired stealth tech.
        
         | scripturial wrote:
         | Avoiding cheap surveillance technologies seems like a big deal.
         | Although I assume once the government works out what you can do
         | with it, it'll become illegal pretty quickly. I assume this
         | research will attract DOD grant funding pretty quickly.
         | Students have to eat somehow.
        
         | ivell wrote:
         | Wheels need a reasonably flat surface to be efficient. Walking
         | is more efficient than flying for short distances..
        
           | numba888 wrote:
           | > reasonably flat
           | 
           | comparing to wheel size. one can use bigger light wheels.
           | that would make landing on short runways possible. besides,
           | wheeling is much easier than walking. two wheels balancing
           | and rolling around is not a problem today. but.. without legs
           | it's just an common airplane, nothing to talk about. the best
           | of both? put small motorized wheels instead of flat platforms
           | for feet.
        
             | bookofjoe wrote:
             | 2 more things that can break/go wrong/stop working
             | resulting in mission failure.
        
               | numba888 wrote:
               | 1 working wheel is enough for balancing. they can be as
               | simple as just a motor in rubber. it's more likely tail
               | or wing will fail than both motors
               | 
               | BTW, here is how it works from Boston Dynamics, it can
               | jump:
               | 
               | https://www.youtube.com/watch?v=LHJKGgwpWY8
        
         | lynguist wrote:
         | > the big thing was the jumping itself, which does not require
         | complex bird anatomy necessarily
         | 
         | No, this is exactly the opposite. The jumping requires exactly
         | this specific anatomy for so many reasons. It stores energy in
         | the joints, it has a specific balance, the jumping works at
         | multiple angles, etc, etc. You can't do better than that for
         | this specific purpose.
        
         | veunes wrote:
         | Maybe there's a niche application we're not considering where
         | bird-like movement is crucial?
        
       | DoingIsLearning wrote:
       | Worth pointing out that EPFL's PR release includes a picture of
       | Won Dong Shin (the PhD that actually built it) as opposed to a
       | picture of the lab's director as it sometimes happens in
       | academia.
        
         | accurrent wrote:
         | THIS. Ive found good advisors push there students forward,
         | mediocre ones tend to push themselves. Academic robotics is
         | plagued with profs who do "everything".
        
         | chinathrow wrote:
         | The article contains an image of him.
        
           | DoingIsLearning wrote:
           | I am assuming IEEE is not travelling the world doing
           | investigative journalism, they will have used whatever media
           | was provided by the university.
        
             | bobim wrote:
             | Yes because otherwise they would have fact checked that
             | there's no lake Geneva.
        
               | uhoh-itsmaciek wrote:
               | Lake Geneva is the English name commonly used to refer to
               | Lac Leman. I suspect you know that, but I don't follow
               | why you object to that name.
        
               | bobim wrote:
               | Interesting, that's the equivalent of me unilaterally
               | calling New York "Nouvelle Amsterdam" then. But it was
               | simply to tickle Geneva's people.
        
               | krisoft wrote:
               | > that's the equivalent of me unilaterally calling New
               | York "Nouvelle Amsterdam" then
               | 
               | This is very common. The name used by the locals is
               | called endonym and the one used by foreigners is the
               | exonym.
               | 
               | For example Zhonghua is the endonym vs China the exonym.
               | Or Magyarorszag vs Hungary. Or Deutschland vs Germany. Or
               | so I not just list English exonyms Lake Balaton vs
               | Plattensee.
        
       | guerrilla wrote:
       | Alright, we're getting there. Still feels like there's a very
       | long way to go.
        
       | cies wrote:
       | If your drone can land on a high spot and save energy by not
       | flying, while using energy to use camera and radio
       | communications, that would be really nice!
       | 
       | Also: the noise a drone makes, gives away it's presence.
        
         | rob74 wrote:
         | Bonus points for being able to perch on a thin branch, wire
         | etc.
        
         | bookofjoe wrote:
         | https://www.silentflyer.tech/
        
       | rauljara wrote:
       | Would love to see a pterosaur / bat version of this drone. Birds
       | use one set of muscles to jump in the air and another to flap
       | their wings, limiting how big they can get. That's because, if
       | you make your wing muscles bigger, then you need bigger leg
       | muscles to support them, then you need bigger wing muscles to
       | support your legs, etc. pterosaurs and bats have tiny little legs
       | and use their "arm" (wing) muscles to do the initial jump into
       | the air. It's just one set of muscles that are used for both
       | functions, which is why pterosaurs were able to get so big. It
       | does beg the question, tho, why we haven't seen any truly giant
       | bats.
       | 
       | This pbs aeons video has a great explanation:
       | https://youtu.be/scAp-fncp64?si=hjeWKGBI7riyjE1M
        
         | type0 wrote:
         | > It does beg the question, tho, why we haven't seen any truly
         | giant bats.
         | 
         | They're mammals, birds have different respiratory system
         | 
         | "Flow-Through Ventilation
         | 
         | Unlike mammals, birds breathe through continuous one-
         | directional flow of air through the respiratory system. We take
         | air in and breathe it out, sort of like the tide moves in and
         | out of a bay. As a result, our breathing system is said to be
         | tidal. Avians have a non-tidal respiratory system, with air
         | flowing more like a running stream."
         | 
         | https://birdfact.com/anatomy-and-physiology/respiratory-syst...
        
           | keyle wrote:
           | Nature optimizes. The bigger you get, the more you need to
           | eat. The harder it gets to fly. Fruit bats eat fruits.
           | 
           | Look at the food source and you'll understand the evolution.
        
             | vanderZwan wrote:
             | > _Fruit bats eat fruits._
             | 
             | The most caloric dense source of nutrition available in
             | nature? I don't see why that is a limitation to body size
             | for a flying animal - quite the opposite!
        
               | TeMPOraL wrote:
               | Plants aren't particularly calorie-dense. Meat, on the
               | other hand...
        
               | the__alchemist wrote:
               | Look at great apes. Large land mammals in general. (Apes
               | came to mind specifically because they usually eat fruit)
        
               | vanderZwan wrote:
               | Are you aware you switched "fruit" for "plant" there?
        
               | Jerrrry wrote:
               | Fruits want to be eaten, Veggies don't.
        
               | mdarens wrote:
               | this is almost in "not even wrong" territory, but for the
               | fact that autotrophs are definitionally the entry point
               | for abiotic energy into edible calories for animals, and
               | the observation that the largest terrestrial megafauna
               | are herbivorous.
               | 
               | bamboo is not calorie dense to humans, because we've lost
               | the ability to digest most of it, but pecans are
               | absolutely more calorie dense than even fatty beef.
               | 
               | all else being equal, an ideal carbohydrate source is
               | more calorically dense than an equivalent ideal lean
               | protein source due to the balance in the thermic effect
               | of food between the two. most mammals outside the
               | obligate carnivores are really well optimized for getting
               | calories from plants-- this is why we have amylase in our
               | saliva.
        
               | fsckboy wrote:
               | fruit bats are the biggest bats
               | 
               | not GP but I think that was the point.
               | 
               | also, volume grows as the cube of linear dimensions which
               | also puts an upper limit on size, as wing surface area
               | only grows as the square (not sure what/how lift grows
               | relative to)
        
           | vanderZwan wrote:
           | That's why mammals can't breathe at high altitudes that birds
           | can, but I'm not sure if that affects the body plan much in
           | terms of size. The largest birds are smaller than the largest
           | mammals on land or at sea. Then again, lower oxygen levels
           | compared to the past seems to be a limitation for insect
           | sizes too (who have an even less efficient respiratory
           | system).
           | 
           | I also don't think it's the warmbloodedness. There are giant
           | mammals in general after all.
           | 
           | Perhaps it is because bats form large, dense colonies? There
           | is only so many resources available in any given ecological
           | niche, so then for any species that fills a niche one would
           | expect those resources to be divided either among many small
           | individuals or a few large ones. Bat evolution chose the "big
           | colony" route, which I assume favors smaller individuals.
        
             | aziaziazi wrote:
             | > The largest birds are smaller than the largest mammals on
             | land or at sea
             | 
             | With all my respect to you theory I think comparing size of
             | animals should not ignore the medium they moved in: water,
             | land or air. Weight is (loosely but still) related to size.
             | It's probably not a coincidence the largest mammals lives
             | on water where they need less energy to supper their
             | weight, and it's not a coincidents the largest mammals on
             | earth are way bigger that bats.
             | 
             | The biggest bats are ~1.7m which is not so far from biggest
             | albatros (3.7m).
             | 
             | Also consider the biggest bird (Ostriches) can't fly. Now
             | I'm trying to picture a swimming gigantic bird.
        
               | totallykvothe wrote:
               | An Emperor Penguin?
        
               | aziaziazi wrote:
               | Right! To complete the unusual list : flying fish and...
               | Amphibious fish! Wikipedia says there's 11 of them. Ok
               | stop procrastinating now.
        
               | vanderZwan wrote:
               | Well, fair. But birds are warmblooded too so that doesn't
               | change much there, and on top of that the difference in
               | requiring bigger _lungs_ for the same amount of oxygen
               | extraction would exactly add much weight per volume, so
               | to speak
        
         | vanderZwan wrote:
         | Robots and living animals have different limitations and
         | constraints though: compared to separate legs and wings for
         | animals, using one motor with some kind of gearbox to switch
         | output from wings/propellers to legs might have a lower added
         | cost in terms of weight . The legs can stay very skinny. The
         | limitation would be how bulky such a gearbox would be, and how
         | much extra kinetic energy loss it would introduce. At the same
         | time creating functioning wings that can also work as legs
         | sounds like it might be a huge challenge in robotics (unless
         | there's a way to massively simplify it).
         | 
         | Definitely an interesting idea that should be investigated
         | though! :)
         | 
         | (Also, I've seen so many "AI learns to walk" videos that I'm
         | wondering if it could be used to find a design that would work
         | for this task)
        
       | bArray wrote:
       | I think I might be building one of these... This is insanely
       | cool.
        
       | Modified3019 wrote:
       | The initial GIF is a bit lackluster, as it looks like it's just
       | walking around dragging a tail. The full video posted later in
       | the article is _much_ more impressive.
       | 
       | https://www.youtube.com/watch?v=-8DJ1a3sLIc
       | 
       | The article itself is worth a read too imo, I found the bits
       | about toes for easier balance and jumping to takeoff energy
       | efficiency interesting.
        
         | ge96 wrote:
         | It's still cute walking around like robots with character
        
       | astrobe_ wrote:
       | Naval versions of fighters can use "jump strut" [1]. For instance
       | the Rafale M [2] [3]. I dislike weapons, but those planes are
       | amazing.
       | 
       | [1]
       | https://www.researchgate.net/publication/257410805_Effect_Of...
       | 
       | [2] https://en.wikipedia.org/wiki/Dassault_Rafale#Overview
       | 
       | [3] https://www.alachassebordel.com/post/20-secrets-about-
       | naval-...
        
         | mhb wrote:
         | > I dislike weapons
         | 
         | A throwaway comment, but huh?
        
       | major505 wrote:
       | You talk like we already don't know that birds are now real, and
       | are actualy goverment drones.
        
       | veunes wrote:
       | I love bio-inspired robotics. It'll be interesting to see how
       | these evolve. And the drone itself (for me do not know why) looks
       | really cute.
        
       | rob74 wrote:
       | > _Despite its name, RAVEN is approximately the size of a crow_
       | 
       | This phrase first puzzled me, but after some googling I found out
       | that in English "raven" is generally used for bigger crows. Until
       | now I had thought that raven was just a more elegant-sounding
       | synonym for crow. TIL...
       | 
       | EDIT: to my surprise, it's the same in my native German: the
       | bigger ones are called "Raben", the smaller ones "Krahen".
       | TIL2...
        
       | pajko wrote:
       | Could this be viable on Mars? Having legs might support a bigger
       | range of terrains than wheels while the flying mode requiring
       | more resources might be used sparingly to overcome bigger
       | elevation changes or to cover a higher distance quicker.
       | 
       | Tough adding legs instead if wheels might introduce balancng
       | issues, the drone could be lowered further to ground level for
       | the time of harsh weather conditions to increase the traction.
        
       | kidel001 wrote:
       | Ah yes, the bird-inspired ... nose propeller.
        
       | adolph wrote:
       | See also this week's IEEE Robot Friday for another uav with bird-
       | inspired legs:
       | 
       |  _We've seen hybrid quadrotor bipeds before, but this one, which
       | is imitating the hopping behavior of Jacana birds, is pretty
       | cute. . . .What's a Jacana bird, you ask? It's these things,
       | which surely must have the most extreme foot to body ratio of any
       | bird_
       | 
       | https://spectrum.ieee.org/video-friday-arms-on-vacuums
        
       | Nezghul wrote:
       | Future warfare would be really fun. You would have to eliminate
       | every single animal you find because it could be drone.
        
         | popcalc wrote:
         | Yes, we must shoot down the flying bears.
        
       | Mistletoe wrote:
       | Is there info on how efficient this is compared to a regular
       | drone? I suspect the boring regular drone with four propellers on
       | each corner destroys this.
        
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