Mechanically Stable Monowheel

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I previously built a small MonoWheel which is a single wheel that runs along with one motor driving it. It balances on its edge like rolling a coin. Monowheels have been built large enough for people to ride in, which looks like a fun project.
My monowheel had some stability control which measured the angle of the internals and modified the motor speed. This meant that the internals always remained at one angle instead of oscillating between driving up the inside of the wheel and falling down again, which is what happens if you just run the motor at a constant speed.
But is there an easier way to make a fun radio controlled vehicle which is inherently stable?
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[@akumabito2008]

Ahh yes, the famous two-wheeled monowheel... 😂

[@Sandux930]

You and me Big Wheel, we could rule this city, or just... fight to the death!

[@nordishkiel5985]

Stereo Wheel would fit, especially with the independent steering and suspension

[@Draugo]

Yeah not really a monowheel now is it.

[@stoatystoat174]

Two-wheeled or Twheeled

[@janikarkkainen3904]

My thoughts exactly. :D

[@jaspurr7467]

A monowheel with.... two wheels?

[@CmdrMartinThompson]

Exactly my thoughts 😅, doenst make it any less cool though!

[@Eidolon1andOnly]

​@@CmdrMartinThompsonIt kinda does. It would be much cooler if it had a more accurate name.

[@davidaugustofc2574]

If you consider the air between both wheels to be a part of the contraption

[@Eidolon1andOnly]

@@davidaugustofc2574 James' justification for calling this thing a "monowheel" is that the two sections are identical and not mirrored, so therefore the two parts are actually a single part.

[@Hunter-ck1zy]

​@@Eidolon1andOnly yeah but each side is independently driven so it's two separate wheels on a tiltable chassis

[@tetronaut88]

Aren't these technically two different wheels, making it a bicycle or a Segway type vehicle? Really cool nonetheless!

[@TarenGarond]

Diwheel is what it's called

[@gidi1899]

how about a 2-wheel-pendulum (2-pendu)

[@XSpamDragonX]

​@@TarenGarondDicycle

[@TarenGarond]

@@XSpamDragonX Yeah that is an alternative name, but I think it is usually called Diwheel when the whole contraption is within the borders of the wheel(Especially when not powered by a human).

[@AlexandruVoda]

they behave more like tank tracks.

[@vladimiryan1335]

It turned out not to be a monowheel, but a free interpretation of a tracked chassis. Получилось ведь не моноколесо, а вольная интерпритация гусеничного шасси.

[@LRBeforeTheInternet]

Thats two wheels, James.

[@0hellow797]

It’s like a mechanical flat tire, it’s very pretty!

[@otthh]

How is this man able to pump out so many high quality projects? Thank you for all this.

[@VEC7ORlt]

Ah yes, 'high quality'...

[@Zveebo]

Having lots of 3D printers!

[@shaunstst]

Lots of sponsors is how

[@computermdms]

​@@Zveebolots of 3d printers makes is possible but he is still doing a lot of design, coding, integration, and video production for each weekly video

[@Zveebo]

@@computermdms Sure, but with the huge amount of 3D printing he needs, having multiple fast printers is pretty essential if not to be a bottleneck.

[@finndriver1063]

Try feet with TPU on the inner edge, and slippery plastic on the outer edge. That way when it leans, it engages extra grip on the driven side but not on the pivot side. That might work, albeit only on slippy floors, and it might slide out of control if you turn without leaning. I do really like the look and function of the pedwheels, they look so steampunky.

[@MrSparkefrostie]

Had a similar thought, thought thought of TPU on the outer edge

[@peterspencer6442]

I wonder how it turns if it leans slightly out of the turn, rather than into the turn? It would move the centre of gravity over the faster wheel, I wonder what effect that might have. Awesome work, the jumping motion as it turns looks super cool and gives it a unique Star Wars quirky robot personality :)

[@mikosoft]

I'd probably tip over more easily

[@davydatwood3158]

I was wondering this myself. Mikosoft might be right, but the whole point of these projects is to try things and see what happens.

[@davidaugustofc2574]

The tip over comment might be correct, there's no indication the faster wheel has a lack of grip, so increasing the normal force over it will have no effect. Karts benefit from you leaning to the outside because the inside wheel is always sliding, it contributes nothing to cornering.

[@mrharvest]

I think you would get better climbing performance if the center of mass was as low down as possible. Also, the swivel mechanism doesn't work for turning on spot but would help reduce slipping (and therefore wear to road surface) for regular turns as the outside wheel track is longer when turning with two parallel wheels

[@Oli420X]

Almost like a tank.....

[@Timestamp_Guy]

you should do the maths to make the tilt axis change the speeds of the inner and outer wheel automatically, so you can just steer with the tilt stick and forward. Alternatively, set the tilt amount based on the differential speed of the motors automatically. Either way, it reduces the number of things to adjust independently. Manually controlling both speeds and tilt at the same time seems too much to handle smoothly.

[@DigitalJedi]

Having it lean out of a turn might also be beneficial, as it puts more of the weight over the faster wheel, hopefully allowing the inner one to slip more easily.

[@wesleyfilips7052]

The legs stuck out spinning on the spot is caused by the legs binding from lateral forces im almost sure. Could be fixed with lubrication of the slot or with rubber bands holding the legs in while theyre coming down so that way the guide pushes them out, rather than relying on its own weight to push the feet back in against the friction of the binding.

[@wurstelei1356]

I also would have the rods move in a square shape instead of a circle with a tilt. So that each side is similar to the one on the ground. In this case it wouldn't matter if it overdrives on one side. The wheel would just snap to the next square face.

[@Rockhopper1]

to stop the inside wheel mech spinning when stuck have auto ratchet lock into the gear wheel, you can print notches on the spacer, as soon as it detects it will be spinning, a peg shoots out and engages with a notch, stopping the spinning and allowing momentum and inertia to force the carriage forward. If you are clever you do not even need a solenoid or a motor to do this, just a counterweight and lever mech can do this, love this design,

[@CharlesVanNoland]

The left/right leaning should occur automatically via gyro sensor determining if it's falling/leaning one way or the other, to keep it level. Another idea is to have the legged wheels canted, so the tops of the wheels are closer than the bottoms, to make it more stable by default.

[@Axolotroll]

James just built a biblically accurate angel lol, Im almost expecting that wheel to start saying "be not afraid" randomly

[@vell0cet517]

Another clever and fun project! I wish you'd make videos where you live-streamed your design/CAD process and talk through your designs as you create them.

[@NerdUndStolzDarauf]

That would reveal his dark secret, that he is actually a sentient CAD program in a trench coat.

[@lucachacha71]

That would be awesome +1

[@arcotkk]

Perhaps adding more weight (that maybe counter-shifts to add friction to the outer wheel as you turn) could help with the leaning, and maybe having the wheels angle toward one another near the top slightly could add some overall balance. Just some theories though.

[@christophertnugent9100]

Can we take a moment to once again marvel at how brilliant James must be to design each of these from top to bottom, plus how diligent he must be in piecing them all together, with a special nod to how great his narration is?

[@frogz]

now make a vehicle with infinite wheels

[@TomS699]

And then add one more for good measure

[@Alkatross]

RIP 3d filament sponsors

[@RupertBruce]

About 20 years ago someone asked me to build a self-returning ball. The design was like a spherical version of this but with actuators where you have legs. That is a lot of actuators! Whilst your monowheel legs make it stable, they resist movement. The actuators deform the surface to push the ball along. My ball never returned.

[@RupertBruce]

@9:40 Mind blown how well that works with passive legs! You make it look easy!

[@RupertBruce]

Tilting would be good for high speed steering with a small difference in speed for the 2 sides of the monowheel

[@bowieinc]

Super cool. Since the center stays put until it’s stuck, perhaps run a couple bars from the center over the top so if it does get stuck, the top bars would come down and around from the top and give it a push forwards by running it backwards.

[@IDisposable]

Like a dragster wheelie bar

[@nerdlord2288]

Always impressed with the mechanical engineering side of your builds,gives me inspiration and ideas for my own hobby builds

[@Simple_But_Expensive]

What about a guide to force the sliders to lift when in the flat portion of the circle? Bolt it to the center section, and have it reach around the outside of the sliders. Also, to avoid the problem of the feet having too much friction, replace them with bearings. If you can perfect it, I would love to see a ridable full size version. Perhaps a collaboration with Furze or Miranda?

[@gearyae]

Yeah, I assumed he had those follower bearings riding in a track at first until the stated problem of them not following the cam. That would make a lot more sense.

[@JacobPatrick1]

I appreciate showing the trial and error. Thank you for showing the real process of development.

[@Eutrofication]

it looks surprisingly organic! like it would be a great blueprint for a slime looking robot that has a flat bottom. the move where the flat part goes around in a circle looks like a little emote! the leaning gives it quite a lot of personality too; show this to Adam Savage and his puppeteering mates, and he might just know how to give it life!

[@davydatwood3158]

It's worth remembering that most actual tanks can't turn on the spot - the lateral forces cause it to throw a track, so they're mechanically inhibited from even trying. I'd be very curious to see what happened if you took this and put a tall body on top of it, something about 5 foot or so. Kind of along the lines of the waitress droids in Star Wars.

[@alexshepherd4469]

What do you mean tanks can't turn on the spot? 😂

[@davydatwood3158]

@@alexshepherd4469 Not sure if you're being serious, but just in case you are: most of the tanks that have existed through the last century would have their tracks come off the wheels if they tried to neutral steer (ie, turn on the spot). So they couldn't. In fact, a lot of tanks didn't even have differential drive - they just braked the track on the side they were trying to turn towards. Now, a *modern* MBT can almost certainly do a neutral steer. But it's mechanically complicated and, if I am remembering The Cheiftain's lessons correctly, still strongly discouraged.

[@CharveL88]

Goes to show that the difference between a cool mechanical oddity and a practical mechanical device is 95% software. Things like the rotation could be fixed by damping the torque when in that mode for example. I love the mechanical ingenuity James puts on display, and it's great stuff! Many, many companies and inventors have come up with similar exercises, but the real hard part is precise algorithmic control, which is why we rarely see concepts like this in many practical applications. I think the next revolution in DIY prototyping ( the last one being able to print and iterate your own parts and plans with a 3D printer) is AI assistance in precision control in the presence of external variables, and the code to implement such algorithms in real time, all at the access of someone who would otherwise not know how to code.

[@1kreature]

The leaning will look awesome you just need to use the same concepts as for cars. Add a bit of mixing from the leaning channel to both motors and steer by only using the leaning stick! It should look awesome and turn much better when you are not trying to do such a small turning circle.

[@XxMurvayxX]

Each finger should have spring tension inward so that when there’s a divot, the bottom stays flat.

[@symply_ajay]

My thoughts exactly

[@imacomputer1234]

This is awesome! just needs more mass at the bottom. I can see this design functionally becoming a round wheel at high speed.

[@UbuntuBirdyMovies]

A monowheel with two wheels - you're a genius! 🤣 But man, I'm so impressed by your engineering skills! I would even say you're a genius!

[@doyouknoedawae]

You should make a drivable version of this. Could be some innovation in that

[@jamesbruton]

I think it might be quite high friction

[@doyouknoedawae]

@@jamesbruton Oh wow didn't expect you to reply. Nice to meet you, and I want to say that I find you inspiring.♥️ We need more engineers or robotic builders like you 🫡

[@bluekiwi42nd12]

I wonder how it would control if you had the turning command control a mixture of the lean and differential wheel velocity. Probably not useful for sharp low speed turns but could work for smooth higher speed corners. Also I had a wild idea that you could make a large scale version where you are seated in the space in the centre

[@willdarling1]

+1 ....or just fed from a small acceleromator?

[@bluekiwi42nd12]

Ya or could use the accelerometer to blend between a low speed tank like turn and high speed lean turn?

[@georgeau2523]

I have no idea what the application for this could be other than a toy but it looks cool, great work. If you could make the legs a compliant mechanism that is part of the printed wheel you might be able to remove 200 parts

[@GamerWannaB]

If you add a tread (similar to a tank) to both of the wheels it might give the friction needed to get out of ditches like you had by gripping the edge of the hole. this would also keep the flat bottom as the tread can be wrapped around and up to make it follow the bearings motion.

[@GamerWannaB]

im also interested what whould happen if you added more weight to the "drivers seat" and see if that would help with the swivel problem where it tips to far and stops making contact.

[@rottenmoonlesbian]

lot of ppl commenting on the fact that it has 2 wheels actually gave me an idea for how to make it 1 wheel, make the wheel much wider, and have 2 or 3 rows of feet on that 1 wheel, and then to tilt instead of tilting the sides have a way to tilt the frame inside so that when its tilted to the left the flat section on the bottom makes the left legs go down and the right legs go upand thus using the change in the center of gravity to turn like a normal monowheel but being more stable bc of the flat sections

[@ebonwestbrook5580]

This design could be incorporated with hamster ball . Possibly moving outer shell plates

[@UnlimitedScore]

Someone took the saying “you can’t reinvent the wheel” to heart…

[@abualahadchowdhury2646]

A ride in a full size version of that monowheel will definitely give the best merry go round experience ever😁😅😅

[@VanillaGorilla7633]

This is crazy. Very Impressed with your skills and engineering here! Next level for real.

[@JinKee]

the wobbly dance would make a wonderful Star Wars astromech

[@TonyBullard]

The best part about it getting stuck and the insides rotating is that the movement of the feet look like it's having a tantrum. Like a dying cockroach on it;s back, or ED-209 falling down the stairs.

[@roguegen5536]

I love these quirky little pedrail contraptions

[@qazaq25]

It probably wouldn't be practical in any way but a mono wheel with a strong enough gyro to allow a driver to be on a seat mounted off the side of it would be kind of cool...

[@FranklyPeetoons]

This channel routinely awes me for some reason

[@rogerdueck9725]

That is awesome! Probably the coolest idea on your channel for a while! Would love to see you put a weighted balancing wheel in it so that the middle section doesn't turn around and gets stuck in the grass. And then I would love to see that thing build in real size...plus you can make it a bit wider for more stability

[@aurigo_tech]

Monowheels: how can we make a vehicle with less moving parts? James: how can I make a vehicle with more moving parts?

[@getstuk87]

as an avid offroader you might be on the cusp of something great. Keep at this one

[@michaelbuckers]

I think the issue is that you effectively have completely rigid suspension. It can extend in the middle but it's no good since it can't retract at the edges, plus it adds no pressure there, just rides along. So as long as the surface is flat and slippy, it's fine. But it struggles to simply move at all otherwise.

[@toordog1753]

Where the guide exists in the inner part of the wheel where the point of contact is on the ground, you could add more flexibility by adding an airbag style system to adjust the amount of stiffness or pressure the wheel can absorb on the ground

[@d00dieb0x]

Maybe add a movable guide to switch between flat and round bottom. That way turning should be easier.

[@ABaumstumpf]

Kinda looks cool - might make a decent toy. It is just kinda stretch calling it "monowheel" when not only is it made from 2 wheels but those also having independent suspension.

[@dylansedillo903]

I think if you were to make it ~25% bigger and add a large counterweight to the bottom it would be much better at climbing over obstacles. I wish I had the time and money, you give me so much inspiration to make projects like these

[@rowski78]

Mono.... One... still waiting for the other wheel to disappear...Wait, is my car a wide motorcycle now?

[@TarenGarond]

No your car is a monowheel, I mean it is kind of obvious when you think about it!

[@stickmandaninacan]

Instead of leaning "in" to a turn, maybe this design could benefit from leaning "out" of the turn, by leaning towards the wheel that is going faster, it applys more friction and traction on the outer edge while releasing the friction of the slower inner rotating wheel that is pivoting

[@mm-rj3vo]

I know everyone is already saying it, but I'll be frank. I was disappointed that it wasn't an actual monowheel. It made me skip to the end. It's an amazingly awesome semi-tank design though!! Kicks ass, as always. It simply isn't a monowheel

[@TheAbyssalStorm]

A monowheel is a type of one wheeled vehicle. I don’t think anyone bothered to say if the wheel could have two sides that can spin at different speeds. That aside, this is very interesting.

[@gajbooks]

Congratuations you have successfully made a 3D printed flat tire

[@SproutyPottedPlant]

That colour scheme…the first one with the white feet looks like one of Eggman’s creations! Add a small green and blue part and it would look like E102 Gamma!!

[@SpermanHero]

Looks like a quirky Star Wars android, the front cog could be an eye of some sorts. Very cool project!

[@eelcohoogendoorn8044]

I think the leaning would add value at speed with the right control. Ideally youd initiate a turn by leaning, and then as the lean angle ramps up, have it followed by a wheel velocity difference in such a manner to follow an arc with a centrifugal force that keeps equal weight on both wheels, given the lean angle. Just varying the lean angle and wheel speed difference independently from one another certainly isnt going to be ideal. I guess that doesnt solve the problem of zero speed turning though. Its always a bit of a hack with tracked vehicles but it turns out particularly jumpy for a tracked vehicles of these proportions apparently.

[@justfellover]

Congratulations! You've reinvented the flat tire.

[@gsestream]

yes you can, a hollow ball vehicle in which a car controls the outer wheel direction, it even floats on water, its all wheel, so whats the difference with a dual wheel and one wheel. look pretty nice, cool. what the grip to reality is not working? well put a sideways (rotation inhibitor lock) rotating spin mass so that the center stays level and the wheels actually spin to move at the proper direction.

[@Davedarko]

Only James is allowed to call something with two wheels a monowheel :P great project!

[@andy_warb]

add a couple of glass domes and you have one of those "orb" vehicles from Jurassic World! Another awesome project James!

[@ImperatorMo]

still heckin slick mate, you're the modern da vinci. looking at what you build i can start to imagine the anakin type future garages.

[@HolmesHobbies]

What delightful projects you make!

[@fpvclub7256]

Love this thing.. I think the issue is the center of mass. If you could move the center of mass toward the direction you're going and probably bring it lower, I think it would climb and be a bit more stable..

[@DutchBlackMantha]

The point of leaning is to compensate for the centrifugal force trying to tip it over. So the amount of lean you need is proportional to the speed you're moving multiplied by the tightness you're turning. You tried it out at a standstill, so the only thing it did was remove weight from the driving wheel. The goal is to maintain equal weight on both wheels. It might work better if you have your controller calculate the lean needed and then auto-balance. Mind you, that calculation would have to assume the center isn't flipping over, so if that happens it might make everything worse. A feedback system that measures the weight on each wheel might be more robust, but would complicate the build.

[@Francois_Dupont]

i think it is one of your best looking creation yet. it is like an insect.

[@GsrItalia]

Sponsored parts: printers, filament, bearings, circuit board Missing parts for sponsors: screws, table, power, screwdriver, board components, electronical components, motors, batteries, servos, radio, set (furniture).

[@christoffkruger]

When it gets stuck, the center rotation must extend something to the surface to reengage traction in such scenarios (But that will need some kind of geering to reverse the direction to get traction in the right direction)

[@CharlesVanNoland]

I feel like the feet should be round instead of square, so that the tangential movement as they extend/retract doesn't cause unnecessary friction while the wheel rolls. Basically, the feet themselves should roll too, instead of having two corner edges that cause a heel-to-toe action as they're rolled onto the ground. EDIT: Oh good, you made rounded feet!

[@kurtnelle]

This is pertty epic. I think that if you use springs or a cam to pull the feet inwards it might help with getting stuck in a ditch.

[@pqr590]

I wouldn't be surprised if this showed up at a burning man in the next few years, super cool idea.

[@purpleYamask]

If it helps, tanks often didn't have differential steering until later tanks in WW2. Even something like a Panzer III or Matilda has a turn radius where one track just goes slower/near-stop. So it /does/ drive like a tank, just not a super modern one.

[@jabonet]

I have been waiting for a long time to see if you make a robot that can travel thru pipes.

[@Dendrowen]

He looks so happy when he turns on the spot!

[@meateaw]

When you run both engines in opposite directions I suspect the sideways movement of the "feet" get them stuck in their channels. (IE they are pulling horizontally against the track, and get jammed stuck out and then lifts itself up)

[@MeleeTiger]

Would love to see a full size version of the second design, large enough to sit inside of.

[@mortontony1]

*building monowheel* *in engineering* "what if.... we added a 2nd wheel"

[@mezzanoon]

Use angled bearings to get your pivoting idea to work, like the Timken ones often used for truck wheels. Tilting at that moment puts it out of the bearings plane.

[@MrSpot337]

Add a guide to prevent the them from falling out. Just like you've added a guide to allow them be flat. Basically, just make it that when on the ground, the bearings are guided in a hollow guide instead of a one sided guide. (Guide = ------, bearing = O) Your curent setup: -------- OOO allows them to get away from the circular path but can fall back down due to gravity or centrifugal force. My suggestion: --------- OOOO --------- Forces them out of the circular path. The lower guide acts against gravity and centrifugal force. Sorry for not explaining it better.

[@Bane9900]

I think if you extended the pedrail concept to infinitely many feet, you would basically have a pneumatic tire with low air pressure.

[@Huntersky2105]

Damn, this got recommended to me quick!

[@rommelfcc]

@James Bruton - rather than sliders, maybe using hinges would work better and much less friction... Then can just attach one servo to power it 4 x hinges 4 x bolts 2 x horizontal platforms Looks awesome 👍🎉

[@ghostAFsky]

It's kind of adorable.

[@NikolajLepka]

Congratulations, you reinvented tank treads

[@bhyre1]

It looks like some sort of expansion joint fixed to the flat side of the hub, that applies pressure to the "feet" would help.

[@BlcKjcK-wt8hz]

Maybe adding a weight at the bottom of the middle part ? It will help climb and get better stability. Nice Project !

[@johncider8554]

if you add some sort of linear actuation on each of the legs you would effectively create a cylindrical centipede

[@darkhertz7247]

Really cool project ! hats off to you man ! Thanks for bringing such things to internet

[@Pystro]

For overcoming rough terrain, I think you need both: The ability to swing the center of mass to the forward half of the wheel (that you get in the traditional design), AND the bottom staying flat (that you get with this pedrail design).

[@101jchristensen]

In SNOW CRASH by NEAL STEPHENSON: The smartwheels of her skateboard, many, many spokes extending and retracting to fit the shape of the ground, take her across the lawn like a pat of butter skidding across hot Teflon.

[@KringusKrang]

I think the spinning on the spot is so cute

[@grantweaver7572]

It lifts when turning because the feet sliders jam when you load them in a direction orthogonal to the axis they slide in. They jam when they first hit the ground which is when they are all the way out so they stay that way instead of following the pattern, so they stay all the way out.

[@MeineVideokasetten]

Monowheel with two wheels.

[@572089]

the leaning function would only work if your wheels weren't vertical. you need to increase the camber, so that at full tilt, one is vertical and the other is slanted

[@dingdingdingdiiiiing]

That's an awful invention, and it's... beautiful. I'm in awe at how you've designed and created it (and the previous monowheel version). I think the problem with those legs is that they touch the ground at an angle, which creates friction and other problems. Perhaps there is a way for the leg holder to swivel, so that the legs would be perpendicular to the ground from let's say +/- 45° of the wheel.

[@bradwilsey9426]

Always fun videos. Thanks for the entertainment. This guys good!