Reinventing the Wheel with Lego
ฝัง
- เผยแพร่เมื่อ 14 พ.ค. 2024
- Hi,
a while ago, I've seen @ArglinPB 's video about chebishev amoeba wheels, and thought that should definitely possible in Lego. And as it turns out, there is actually some pretty recent research about that, and I'm pretty happy about how the proof of concept turned out!
Enjoy watching,
2in1
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FAQ:
Check out Arglin's pinned comment, it's explained much better than I ever could
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Resources/Credits:
Research: www.geogebra.org/m/kq8dr2JY
www5d.biglobe.ne.jp/~the_imai/...
Arglin's videos: • REINVENTING THE WHEEL!...
• The weirdest wheel jus...
Chebyshev linkage: en.wikipedia.org/wiki/Chebysh...
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Links:
PDF Instructions: bricksafe.com/files/2in1/amoe...
Rebrickable (part list and .io file):
Wheel: reb.li/m/170956
Car: reb.li/m/170957
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Timestamps:
0:00 Intro
0:06 Traction Explanation
0:34 Building/Linkage Explanation
2:00 First Tests
2:21 Amoeba Car
3:06 Slope Comparison
3:33 Better Car
4:37 Slope Comparison 2
5:00 Thanks for watching!
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#lego #technic #vehicle #mechanism - วิทยาศาสตร์และเทคโนโลยี
![ตรงที่เดิม - ฝน พรสุดา [ต้นฉบับ : เบส ขวางหวัน]](http://i.ytimg.com/vi/c5YnbGEztI8/mqdefault.jpg)
Incredible work!! I was about to message you to see if you could recreate an Amoeba wheel out of lego after a few people started making their own models, but it appears you were already ahead of me as well. :)
Some answers to FAQ:
*Q: Isn't friction supposed to be constant regardless of contact area?*
A: Yes! In physics, we are taught that F_{s} = μN; F = friction force, μ = coefficient of friction between two materials, N = Normal force. Contact area has no involvement here, as counterintuitive as it seems. The reason for why the circular wheel slips, as several of you have pointed out, has to do with the contact surface not being always the rubber band but rather the plastic rim of the wheel itself.
That said, there could be a benefit in terms of traction which occurs, not because of a change in the coefficient of friction, but because of the maximum limit the materials are able to bear such forces. For example, a regular round wheel can often get stuck in mud due to the small contact patch. The wheel spins, slips, and it digs itself into a hole. Amoeba wheels, however, distribute their load across a much bigger surface area, reducing the chance of sinking. And even if it does sink, it can actually dig _into_ the sediment or snow, and actually pull itself along, kind of like a boot with a studded bottom or racket shoes to get more traction in snow, or a continuous track... which speaking of.
===
*Q: Aren't these just functionally identical to tracks?*
A: Nope! Their behaviors are actually very different; Amoeba wheels are actually much worse than tracks for a variety of reasons.
1. Continuous tracks mold around the wheels for a vehicle, so they can deform and change shape (even if the wheels don't have suspension, the tracks do still deform a little bit). Amoeba wheels, however, are rigid mechanisms. They can change shape, yes, but they can't warp to better match the terrain. As a result, these wheels are actually much more mechanically similar to a regular wheel than they are to a continuous track, even though visually it does look like one!
(Fun fact: they should not even work! If you are familiar with the Chebyshev-Grubler-Kurtzbach mobility formula, this is a mechanism which violates the equation, stating that it should be a rigid structure. It might be one of the only "complex" mechanisms which violates the mobility formula without an intuitive reason or rigorous proof behind why... spoilers, some amoeba wheel configurations can roll, but some can't!)
2. The amount of moving parts creates more points of failure than a regular tracked vehicle.
3. The precision required for those moving parts can be pretty tight sometimes, depending on the purpose.
4. It's not shown here, but the much further generalized amoeba wheels are next to impossible to construct due to the challenge of avoiding self-collisions. (But not impossible! I've been very very impressed by the amount of 3D model submissions I've received from people pulling them off. A shout out to temporaryyesyes, Skip, 2in1, and SomeFakeGamer for pulling off the much, much harder Roberts Amoeba wheel.)
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*Q: Isn't this completely over-engineered / impractical?*
A: (See answer above.) As one of the co-inventors, yes. Yes it is. And that's the point, that's the spirit that I like to keep up to. This is more of an art-form, than a strive to be revolutionary. (Pun not intended.)
My entire channel is based solely on over-complicating and over-engineering the absolute hell out of things. I have a lot of fun doing this, and so does Imai-san, the original inventor. If you check through his other creations, you'll see that many of them are actually intended for toys. None of them are actually practical, just merely a fascinating gimmick. And it makes me incredibly happy to see this silly little goober of a mechanism get some love after almost a decade of obscurity.
So again, I just want to say thank you to everyone who has watched and contributed to this. We could not do this without you.
Oh well, yeah when I saw that second video I was pretty inspired to try to build it in Lego. And to be honest, I'd argue this isn't even as far from being practical as I expected, and with Lego tolerances it's also pretty easy to simply not care about the exact lengths... I've also tried around with the other designs, the biggest problem is just the crank, that is obviously way easier to recreate in poly bridge than in Lego, but maybe that's a project for the future. But thanks for your research, explanation and inspiration, that helped a lot :)
@@in1I love your videos
Hi @ArglinPB, love your videos. And great Lego recreation @in1, keep up those out of the box ideas, even if you didn't came up with it.
@@michalvallo5051 I have to give 2in1 full-on props for it. I at least managed to get the theory rounded out pretty well, but the transition from theory to practice requires a separate skill-set to understand.
None of this stuff that 今井さん, ME, Chakot, Scrap, and I figured out could be realized in the real world without wonderful people like 2in1. :)
Cracked
At first it sounds cool, then you realize it's just a more complicated tracked vehicle.
Yeah, you could argue the structure is more rigid and stable than a comparable tread because of the spokes. But of course this is more a fun than practical project.
@@in1 Maybe not, you could argue that, because of the fewer linkages and parts, it's actually less maintenence costly than a tread (although I have to add that a tread is much more "speed-capable" AND simpler (fewer part variantion))
@@projectdeveloper9311 Depends if you're using a steel or rubber track.
Not really. A tracked vehicle is still a wheel against a flat surface. This doesn’t have any wheels.
It’s a tank tread but worse
Super cool to see the amoeba wheel brought to life! I had just assumed there would be some self intersection or something making that impossible, glad I was wrong
Yeah to be honest I'm kind of surprised myself how smoothly it worked out
@@in1 yeah, combine it with the self-regulating movement of insectoid movement patterns and you have some serious traction
Hmmm.... i now have 3 questions about this :
1) what about how it works if there is a bump on the road? / how it handles terrain irregularities?
2) how does it handle high rotation speed?
3) how os that any better than treads or tracks?
I've done some of my own testing and to answer your questions, 1: it doesn't very well, its best on flat ground however it has proven to be quite effective in the snow, 2: it should be possible to make it handle faster rotation speeds however it will never be practical at anything over 4x what was shown in the video as it will just shatter, 3: it's not, it's more of a gimmick than anything they make quite good desk toys but i highly doubt that they have any practical use
Yeah, exactly as @Temporary_yesyes said, this is mostly just a fun project. Combined with the 4:1 mechanism it's probably as good or maybe a little bit better at going over bumps than a wheel of the same size, but definitely not a breakthrough. Speedwise at least my design can handle even higher speeds more or less, but it is pretty fragile when it comes to sideways forces. And yeah, this is pretty similar to tracks, but with the addition of having direct spokes to the parts of the track and a bit more rigid body in general. With that in mind, it's probably still more like an answer in search of questions, but it's kinda interesting that constant-height wheels don't have to be circular.
@@Temporary_yesyesguess posting a video of that could boost your publicity ;)
I don't care about internet points, plus it broke which shouldn't be too big of a problem but its a pain to rebuild the crankshaft. And there are other better designs for the crank that i am waiting to see how much better they actually are before rebuilding@@revimfadli4666
It's important to remember that contact area does not increase traction. The force of friction is equal to the coefficient of friction (which is determined by the two materials in contact) and the normal force between them. This wheel would reduce ground pressure and increase consistency on the road, since larger contact areas mean hitting a little smooth spot on the road won't send you flying off the road.
Yeah, it might improve the adhesion a bit, but you're totally right
By increasing the surface area you decrease the shear constraint. For a rubber part (tire for ex.), I think that it helps because with high shear the rubber may rip before the contact surface starts to slip.
But obviously, not on a small scale model...
This is not true for rubber
”Contact area does not increase traction”
This applies to hard materials. In the case of rubber, increased contact area does increase traction.
I was just about to send you that video before I saw this. While the math to get unit lengths could be difficult, technic is the perfect testing ground. They are insanely interestinv and cool.
Not a super fair comparison due to the layout of the robber bands from grip
You can see at 10 degrees the wheel is only slipping in between the rubber bands
The amount of surface area covered by the rubber bands is very very very unfair against the normal wheel
Came here to comment the same. A full rubber band cover would be more accurate for comparison
You should run the test again, but this time you should make sure the same weight is applied to each wheel, and that the wheels both rotate at the same speed.
Theoretically, if two objects have the same friction against a surface and the same weight against that surface, it doesn't actually matter how big or small the contact area is. Having more surface area would not produce more traction, because the weight of the object gets spread thinner over the larger surface area.
Doing a more proper test would be a great way to show this principle working (or maybe even not working!) in action!
You're totally right, I'd like to refer to the discussion below icegoggle's comment for that
Surface area not increasing friction applies to hard materials.
In the case of soft materials like a rubber tire or rubber band, increased surface area improves grip.
A technically complex pseudo ped-wheel, that sacrifices simplicity for enhanced ground contact.
Fantastic design! I love the idea of complex wheels. Can't wait to see more!
Awesome! Your solution to increase the gradient melted my brain. New subscriber ✌🏻
i've been working on my own amoeba wheel for quite some time now, while I am making a different one being the -1:1 dodecagon amoeba which is harder to make, it is still very impressive that you got this working so fast and so smoothly. I've already started making my own one of these from 3d printing. If you ever do a follow up video i would really like to see a working dodecagon as so far I'm the only one who has made one successfully even if it barely works
You mean that roberts linkage wheel? Wow, I have, to be honest, no idea how to get something like this to work where you have to arrange 12 non-intersecting bars. Did you also choose a crank design (like in my Lego one) or is there another idea I missed?
@@in1 yeah it was the roberts linkage wheel, it works really well but is super fragile. Your crank seems optimal for this design, but for the roberts each one needs its own crank because you can't get any connections from just one crank as it would pass thru the path of one of the spokes. For any actual roberts wheel it ends up just being super wide and unstable, I've tried to build a second one so that there are always 2 track pieces on the ground but it keeps shattering
I just finished building the octagon amoeba based on your design and im super surprised at how smoothly it went. It took me roughly a month to get a working design for the dodecagon, the octagon is much more straight forward and I was able to finish in roughly an afternoon
@@Temporary_yesyes Yep, I'm also pretty surprised. Wouldn't have expected it to actually be remotely practical but it worked out...
These videos with (relatively) simple mechanisms are awesome! I`m doing Mindstorms with my kid, and there`s no shortage of complex step-by-step robots and cars. I like them, but its hard to learn something with the overwhelming amount of details. Your videos are just perfect - small and simple. Thank you.
Congratulations. You've invented a flat tire.
This might be the first time I've ever seen "reinventing the wheel" make sense xD Nice job ^^
This wheel could probably really useful in real life, BUT it could only be used for really slow vehicles. If you run it too fast, it will just shake itself and the machine it´s mounted to into pieces. You would also be paying a lot more for something like this, the maintanance will be a pain in the ass because of all the moving parts and special mountings are also needed.
Even though this is a really impressive solution to a rather big problem (the lack of traction of conventional wheels ) all the effort would you have put into this if you wanted to sell it irl would be for nothing because this problem was already solved with something called tank tracks.
Despite all these drawbacks it´s a fun project and I really enjoyed it🙂
This is an interesting idea for trying to make a compliant mechanism of.
Fun idea. It is interesting because with air filled tires, they have steel wire inside to help give them shape but they also sag toward the ground a bit. I'd imagine it's giving a similar increase in patch size through a similar mechanism. But you can't really see that with the typical mass of a lego car. So this is kind of a cool way to visualize the deformation of rubber tires.
Very nice video, and I did not know such mechanisms existed. And building it out of Lego is even better 👍
One small thing though. In an ideal scenario (which this is) the traction is not depended on surface area. Just the Force pushing orthogonal to the surface.
HoldingForce = NormalForce x FrictionCoeffitient
That means that the wheel can not climb steeper angles than the round wheel.
But why did it in your experiment. I have a theory on that: Your normal wheel has the rubber not at every surface of the wheel, but just in some places. While whatching the wheel failing the 10° slope it can be seen, that the Wheel slips, and chatches of the rubber again. It is just slipping faster when it has no rubber, than it climbs. That's why it probably fails.
A bigger rubber band around the whole circumference would most likely also get approx. 18°
Maybe worth a small experiment 😃
But again, nice video and a new aub from me 👍
Okay that's really counterintuitive, since a higher surface should produce more heat when sliding with the same speed, but the equation is right... No idea. I've tested it with a better rubber band setup and also with a correction to the weight difference, and while the wheel has a bit better traction it still doesn't come close to the 18°
Maybe there's still something I missed tho
@@in1 yeah i find it counterintuitive as well. What can help to understand is that a larger surface corresponds to less pressure and the so the force at each point is less. Why your better experiment did not work is weird. I have some ideas like
-the center of mass being different or/and
-due to stretching rubbers this is not an ideal case.
-Also the "radius" of the amobea wheel (to the ground) is one hole smaller
But most likely not worth to try to understand this, since it is just a cool demo as is :D
You're right, that makes a lot more sense. Maybe the friction of the rubber band just practically isn't proportional to the weight, but probably it's just problems with my test. I just wouldn't expect the difference to be so big if it was just that
Probably the wheel and the machenism are made of different types of plastic (so they have different friction constant), that's why one climbs higher than the other, plus, the mechanism weighs more and that gives it a huge advantage in terms of friction. Last thing is probably the wheel isn't a perfectly shaped wheel and that makes it slip every now and then.
I've corrected the weight in my second test, but yeah, maybe it's just the rubber band friction difference. I mean, a higher surface area still has advantages, there is a reason why treaded vehicles exist, but probably the main reason is just weight distribution and not traction
It would be cool to see an offroad vehicle made with these parts,
maybe you could use the old 8824 Hovercraft rubber parts for more traction?
You're right, that could work
This reminds me of a Flash game where you play as a somewhat pixelated green slime that goes over obstacles and something
Woah ive never even tried to think of linkeages like this, super cool
What a cool concept!
This is like a single (ish) axle tank tread. Very clever!
Cool construction! Great!
I was expecting nothing, but it turned out amazing
wow
I'm really happy to see the amoeba wheel in action!
YO. I shoulda known you’d’ve seen the amoeba wheel haha. rad build my friend
Wow, that is so cool!!
This looks incredible! Im blown away by the engineering behind it. But it has so many moving parts for something ad simple as a wheel...
Yeah of course, a car with this wouldn't last 10 km/h I think :)
The French have actually tested a frame-wheel proto-tank.
The song sounds like beyonce halo
Also keep in mind this doesn’t help friction, ONLY adhesion so make sure you take good advantage with a good tire
That is beautifully impractical ❤😅
Try shifting the weight to above the axle. Should get some better performance out of it. Also if you can you should try putting these on a 4 wheel drive train if you can
You simulated a flat tire with a rigid body, neat!
Imagine making a car with these. This is probably considered cursed
nah this is entirely practical I have no idea why you wouldn't use these :D
Definitely not for high speeds.
@@in1for snowy and icy terrains, it honestly could be an interesting alternative to treads.
@@justsomeguy5628 Yeah, you're right, I mean basically these are triangle treads with spokes
Although beeing extremely cool, this mechanism howfully looks like an over complicated track system with extra steps
Interesting concept
I knew of Chebyshev's linkage, but using this way js very impressive.
finally, after millions of years, he figured it out
You know, that wheel idea you can use that in making a Lego marble machine. You can have the one motor drive both the big amoeba wheels and the lift mechanism, another idea I suggest you could use the simple switch idea from your ideas of controlling 2 outputs with one motor video.
Ooh a lego ameboa wheel? Super cool
Congratulations you made low tire pressure out of legos
This is one of the cool propulsion methods we'd have if, like, Ford had patented tires, and then every car manufacturer had had to develop their own unique technology for moving a car around...
Yeah that was chaos when watt patentented crank and slider
I like that you basically reinvented tank treads
Soooo,,,,a track, you rediscovered what a track is, I'm proud of you.
I guess a compact track with spokes and more stability, yeah
So cool
Very interesting concept and good way of demonstrating it. The comparison to the round wheel was somewhat lacking, though. On the amoeba wheel you have rubber bands going completely around the liftarms while on the round wheel they are going criss-cross only occasionally touching the "ground". You can see that the round wheel is able to get traction momentarily when the rubber band passes the contact patch. The amoeba wheel also has a little bit more weight on the driving wheel. For real life application I'm doubtful if amoeba wheel provides any advantages over wheels or tracks while having quite drastic disadvantages.
Yeah, it might have a better adhesion, but that shouldn't be as useful in real life that it can replace anything
they really done reinvented the wheel before GTA 6
very nice!
Good concept , like a chain drive
Yeah kind of but more like a gearless chain drive with spokes
@@in1 yes that’s neat, I’m wondering if that wheel molecule can be enlarged and also have functionality of suspension, not just aligning to a flat surface but also adapt to obstacles, that would make it interesting for a Mars robot for example
@@d4ro Yeah, I'm currently trying to figure out a few more amoeba designs, I might post this in a channel post in the future. Basically, there are designs that work a bit differently, called "pancakes" because they are flat. You might wanna look into Arglin's second video for that (linked in the description)
That is amazing! Feels like a hybrid of rolling and walking. I have a strong urge to 3d-print a few and make a 4 or 6 wheel drive platform...
Also possibly implement some in Minecraft with the Valkyrien Skies mod
You might wanna look into the poly-science section of the poly bridge discord for that... someone built a minecraft version with create mod ( discord.com/channels/461344432302587914/692977958985531431/1200361486778892288 ) and I've also seen 3d print files. These wheels are really really fun to mess around with :)
@@in1 I'm already in the process of watching the original vid you quote as inspiration, really interesting so far, and am already thinking about the potential adjustments on the splay angle. Thanks for the link!
@@in1 (BTW the build you linked IS using Valkyrien Skies)
Oh, I see :) I've never gotten into modded mc so I have no idea
Very good work ! May be a stair climber, one day . . .
that's really fun...
I wonder if it might be able to climb steeper slopes in a rear-wheel-drive configuration, with the accel pushing back on said rear wheel, rather than lifting up the front...
I mean you could also build an amoeba 4x4, if that's your main priority, but yeah
You could get a lot better results using wider, flatter rubber bands
Could you double up the wheel but extend the grey spokes beyond the yellow bars so the 'wheel' rests on a grey tripod all the time?(improvent on the idea of making a spoked wheel but with a shoe on each spoke instead of a rim).
That would totally work, yep
If I remember properly this was one of the inspirations to invent tracks..
Tracks were invented three different times before 1850 (George Cayley in Britain, Józef Maria Hoene-Wroński in what is now Poland and Captain Dmitry Andreevich Zagryazhsky in Russia), so that's really doubtful.
@@GoranXII I know I might be wrong, I never did any research myself but I am a tank enthusiast so I'm basing things off what I've seen and what I can remember
@@BLEEN-lk3mj Well I admit those early inventions never went anywhere, so it might have inspired later inventions. I just think it's funny that, sometimes we find evidence that ideas are a lot older than we ever thought.
while it does seem like that, this is actually an invention from the poly bridge community that we made after about 1-2 years of work so they are very new
imagine a steam powered vehicle with wheels like this where each section of the wheel is like a big stretched out rubber mat or something that can kinda grip around terrain
like an offroad train
Will it fit my honda though?
Finally… an update!
I don’t think it changes anything since friction is dependent only on the material and force applied, not the surface area, I’d say it performs better because of the slight increase in weight. It was interesting to watch nonetheless!
You're totally right, I'd like to refer to the discussion below icegoggles' comment for that
This is not correct.
Friction does depend on the surface area when dealing with soft materials like rubber. It’s because the real area of contact increases along with the apparent area of contact.
It’s only hard materials where friction is independent of the surface area, because the real area of contact remains the same even if you increase the apparent area of contact.
IRL tires solve the slipping problem with grip patterns on tires. So most cars can drive up a 50 degrees ramp.
tread patterns are for shedding water, not increasing grip.
4:30 *thoughts* 75 percent of the time, it works all the time.
try making it go up backwards so that the amoeba wheel is the support wheel
I guess it works, but... low pressure pneumatic tires kinda achieves a similar effect if the goal is a larger contact patch.
0:23
please correct me if I am misunderstanding something, but in school we were taught that friction stays constant in regards to surface area of contact, as long as weight dtays equal.
if you have a smaller surface area, there is more weight pressing on the same area, which cancels out the effect of less area to do the job
Yeah, that's a mistake in the video. Actually, the adhesion gets improved, so that's still significant for the traction.
@@in1 thanks ☺️
@@in1 maybe you could write a correction and pin it? 🤷♂️
@@georgplaz I don't want to remove the current pinned comment (because that's the person most of the amoeba stuff originates from), and theoretically adhesion is also a kind of friction, so I don't think that's worth it
@@in1 I will add the correction to my comment in a moment, you can re-pin it later on. :)
I really wanna see how you will steer with this thing
Friction formula doesnt contain surface area, thats because the larger the surface area of the wheel, the less the pressure on each square millimeter will be, so essentially, make the surface bigger is useless.
The only variable is the friction coefficient and it can only be made better by using rubber or similar materials.
Yeah, that's pretty weird. I'd wanna link to a discussion under icegoggles' comment for that: th-cam.com/video/Geu_kDHcrLM/w-d-xo.html&lc=UgyqDQxd6NAhFXapXEN4AaABAg
I like your videos
This assumes flat roads, no wear and tear and it is more expensive to produce. Also I'm curious on how heavy of a load it can carry in comparison to the normal wheel.
But it is an interesting mathematical challenge and for that I apprechiate it.
I'd also be interested in comparative torque and speed. The 4 to 1 ratio really limits top speed, and those linkages must have torque losses that are a lot larger than traditional wheels. Combining these two effects aren't great for efficient designs.
@@varmituofm I forgot about those aspects. They are pretty significant when we look at wheels.
great idea, but more moving part mean more likely to break down. not to mention when the car won't start, you will have a hell of a time trying to push it
The car starting part shouldn't matter, the power transmission is exactly as smooth as a round wheel. And technically a tread has more moving parts and is still practical. But yeah, this won't be practical with a normal car :)
It’s basically a weird Tank track
I wonder if it would be able to climb steeper slopes if it were the back wheel instead of the front wheel.
But what's the maximum speed these can achieve, high speed would it be balanced or even able to do 70mph plus
with the second model you could prolly reach higher speeds, but you might need a more solid 4:1 gearing for that
How did you figure out what speed it needed to spin to prevent flipping?
The axle can be driven as fast as it wants (not addressing slippage).
If you meant how he figured out the relationship for the black guide beams at 3;30, the relationship can be described as such:
n{Sides} / n{Pedals} = R{Pedals} / R{Sides}
n{Pedals} = Number of pedals on the axle.
n{Sides} = Number of segments on the rim.
R{Pedals} = Total revolutions taken by the axle.
R{Sides} = Total revolutions taken by the rim.
(This also assumes R{Pedals} / R{Sides} is a natural number, though it can also be negative sometimes.)
Because there are 8 rim segments and 2 pedals, then--after simplifying--the relationship in revolutions is 4/1, which is why 2in1 uses a 4:1 reduction for the black guide beams.
(The one in the video counts as two pedals, despite being one segment. Defining it that way makes more sense if you look at other amoeba designs shown in the videos linked in the description.)
3:30 *wobbly, yet efficient*
I am so used to regard „the wheel“ as the best way to … this is better, though it frightens me.
Gl, hf.
Yeah, I mean there are a lot more ways to increase the friction other that building a wobbly wheel, but it's just cool to see working
You are a genious
Makes you wish they would make those axles out of hardened rubber so you can have increased grip
I'm very curious to see how it would act on uneven terrain.
Edit: found the answer to my question in another comment.
"That's just a wheel with extra steps!"
Ooh Amoeba wheel
I get the feeling that this would have applications in rough terrain.
Surface area doesnt affect traction, if the surface area is lower, theres more pressure on one spot which makes it have equal friction to many points with spread out weight
This only applies to hard materials. The real area of contact does not increase even if the apparent area of contact does, so friction remains the same.
Soft materials like rubber increase the actual area of contact because of deformation and a larger area has more traction as a result.
I’m gonna be honest, chief. This is the concept behind airing down your tires for better grip.
Great video! But increasing the contact area doesn't increase friction. The force of friction depends on the normal force and the coefficient of friction.
Maybe it's adhesion? I've run tests afterward with a better rubber band layout on the round wheel and more weight, and there is still a noticeable difference...
@@in1One reason I can think of the increased friction is this: the amoeba wheel has its axis of rotation lower than the round wheel, this causes the inclination of the car to be smaller, resulting in more weight applied to the amoeba wheel than to the round wheel (hence more normal force).
I also see that the speed of the round wheel is too much, because it's slipping, and it's important to know that the dynamic friction (when it's slipping) is less than the static friction (when the point of contact doesn't move). So I recommend lowering the speed of the round wheel (this also applied to the amoeba wheel) until the wheel doesn't slip. In this way the friction will increase a little, I think.
It’s sort of like some weird in-between of wheels and tracks.
Behold - the invention of the flat tire. :-)
This reminds me of the wheels on he mans mini van
You should see @ArglinPB 2nd video on the amoeba wheel and make his negative amoeba wheel
Dirt roads should last longer with the increased surface of this kind of wheel.
I wonder if you could make a bicycle with this kind of wheel.
I wonder if this could count as a walking mechanism in the sport of combat robotics.
Pov you don't use tracks but know somsing different
You re-invented a discretized version of a tire with some of the air let out.
isnt this a lot like how air pressure holds a tire's shape (being the gray pieces) and a mildly deflated tire being the malleable ground connection point (the yellow pieces)?
Yep, exactly. You probably can't reach a ground contact like this with a deflated tire, but obviously there are a lot of reasons why you probaby still want a round wheel on your car
@@in1 yeah definitely. Tires irl can’t reach a deflation with a ground contact level like this mostly because of the fact that they would deform too much for the seal to remain in place, which would just let all the air out of the tire. If they were connected and sealed straight to the rims though (like F1 race car tires) then it would work
Couple things:
Area of the contact does not affect the grip. Only downward force and friction coefficient does. We learn that in physics class.
When comparing the wheel, you used bands going across leaving wide gaps of smooth beam. That's cheating. If you want to compare them, put a band around the wheel, not across it.
The construct looks cool otherwise. Might provide smoother ride over uneven terrain I presume?
Yeah, that's a mistake in the video: Not friction is improved, but adhesion. I've re-ran the tests with a larger rubber band around the big wheel, and there still is a noticable difference. You could argue the advantages of this design are that it has the advantages of a tread but with spokes, but obviously this is far from being practical.
@@in1 Do they have the same axis radius? I think regular wheel is sitting higher and the whole device is tilted back, making it loose grip faster. Can you move the axis mount lower on amoeba wheel to match it, or the rear wheel higher on the circle one so the assembly stays at the same angle?
They both have a "radius" of 6 I think
The area of contact does increase grip when the material is soft like rubber.
The physics class formula applies to solid, hard materials. Their actual area of contact doesn’t increase even if the apparent area of contact does, so area can be ignored.
So if you want more contact area, use tracks instead of that weird wheel aha.
2in1 bricking *has a problem* what people try to say to help "You don't have to reivent the wheel just use something else" 2in1 bricking REINVENTS THE WHEEL " ok problem solved!"
Is it able to bend over bumps?
I guess you could easily replace the spokes with springs, but in its normal form it can't do that
The height of the axle isn't constant though, is it?
It is... that's the point of the chebyshev linkage