Amoeba wheel
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- เผยแพร่เมื่อ 8 ก.พ. 2024
- This wheel is a combination of 8 Tchebicheff's four-bar linkages
• Tchebicheff's four-bar...
Input: blue crank shaft.
1 revolution of the wheel corresponds to 4 revolutions of the input crankshaft.
1 revolution of the wheel corresponds to approximately 8*L linear displacement of the blue crankshaft. L is length of the brown plate.
The wheel can roll when the crankshaft is pushed horizontally (red arrow in the video’s last scene).
This wheel helps reduce pressure on the ground.
Thanks to Arglin Kampling for providing me with the wheel dimensions.
See the wheel prototype:
• Reinventing the Wheel ... - วิทยาศาสตร์และเทคโนโลยี
Hmm, maybe my idea for a tracked off-road unicycle isn’t so far fetched after all…
I ride an off-road unicycle! (pedal-powered, not electric) I bet it would be very difficult to ride as unicycles require skid rotation of the wheel to steer... and you need to steer to keep your left/right balance. I'd think the track plates would need some crown as a unicycle is usually leaned over to some degree.
FAQs BELOW!) It's happened! It's here!
I'm really glad the animation has improved greatly since the prototypes you were sharing in inventor in the beginning!! It works fantastically smoothly.
Some answers to FAQ I have received over the past few months, transferred from my comment in 2in1's channel:
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*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, and seeing it modeled professionally is a dream come true.
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.
Great animation! Glad my prototype could help :)
An ingenious design.
Gotta thank arglin for that
Interesting concept, to have the tracks on individual wheels, instead of across several of them.
This is awesome! I'm going to have to design some weird tank thing for war game miniatures, now. :)
Very cool
Seems like a good replacement for tracks. You get the large contact patch without the complex mechanism of normal tracks.
unfortunately it is more of a gimmick than anything as it is more complex than a traditional tank track and with both the positive chebyshev amoebas and the negative roberts amoebas each connecting rod has to be on its own plane which severely limits how strong it can be. Along with it being rigid so it cannot easily traverse anything that isn't relatively flat.
could the spokes incorporate some shock absorption in them? otherwise it seems (to me) like it would be too rigid to smoothly traverse irregular terrain.
That is indeed correct. The wheel's shape does change, but it's still too rigid to mold to the shape of the ground.
I have tried replacing the spokes with springs+dashpots though and that does indeed solve the problem, for the most part. :)
Interesting
Wow, cool! I wanna 3d print one now
Does anyone know if there is torque variation in this drive? How about vertical displacement leading to vibration (assuming a flat surface)?
What are the proportions of the crank throw, plate length, and spoke length?
For the proportions see:
th-cam.com/video/e3JI4wYIXEs/w-d-xo.html