Open Dog is one of the coolest projects on the internet

@Alessandro---

3 ай бұрын

James Bruton IS possibly the coolest creator on the Net.

@NealFosterHD

3 ай бұрын

Has anyone else made one from his designs?

You might have room in the hub for a third disc to give three phase drive . That should prevent the cyclic load that you're hearing. You might have to split the cam to get the bearings on.

The belt is actually quiet genius, as it's limiting the torque and prevents the gearbox from exploding

@GaryTheRCcar

3 ай бұрын

I think it's better for the motor to just stall, the belt will wear out real quick shipping like that.

@ashtonhoward5582

3 ай бұрын

​@@GaryTheRCcar but the belt is cheaper.

@Unmannedair

3 ай бұрын

Belts are basically mechanical fuses

@conorstewart2214

3 ай бұрын

@@ashtonhoward5582 Just current limit the motor, you can limit the torque then too. A motor stalling isn't necessarily bad, its what happens after it stalls that is the problem, like continuing to run current through it and at that point it is just a resistor.

@GaryTheRCcar

3 ай бұрын

Just because the motor stalls doesn't mean it will break. as long as it doesn't overheat it will be fine. He can limit either the voltage or current to achive this@@ashtonhoward5582

My favorite part of these videos is when James puts his hands in places where the 3d prints can crush him

@MattDunlapCO

3 ай бұрын

Holy crap. I was whole-body cringing and holding my breath when he was trying to stop the drive with his hands.

@AJ-Palermo

3 ай бұрын

I was thinking the same thing! With the 20:1 gearbox that's over 4500kg/cm!! A finger probably wouldn't even slow the motor down! It'd be a slight increase in current draw and a significant decrease in fingers!

@MattDunlapCO

3 ай бұрын

@jamesbruton, please do a follow up where you feed meats and various other objects into the gears or between the belt and idlers! Another demonstration showing how much more dangerous these machines are when wearing gloves would also be fun.

@AJ-Palermo

3 ай бұрын

@@MattDunlapCO that's a cool idea! I know firsthand (pun intended) how dangerous gloves are around machines with rotating parts. I work in a warehouse with conveyor belts, I'd never stick my hand in anything, but I was curious and stuck just my glove between the rollers, and even though the rollers lift up so they don't crush your fingers, there was still an impressive pulling force on the glove. If you were to stick your finger in there, it would definitely hurt, but you wouldn't lose it. With a glove on, especially a grippy one, you could easily lose your fingers or hand, maybe even your arm!

@MattDunlapCO

3 ай бұрын

@@AJ-Palermo my daughter may have lost fingers to a drill press if she'd had on gloves tougher than cheap cotton knit. Thankfully the material failed before her hand.

Great video as always James! For once I might be able to help you out with a design. I've been working with a university rover team to design and build cycloidal reduction drives for use in our 5 axis rover arm. The idea you tried at the beginning of the video is actually what we're currently using, with the output of the gearbox being the housing of the cycloidal itself. If you'd like to take a look at our cad or ask any questions about it's performance I'd love to have a chat with you about the subject.

@kimtae858

3 ай бұрын

He doesn't read comments after the first few hours of a video going live. Twitter or Instagram are better places to get his attention, but be succinct about it. He doesn't read long messages, lol.

@Hawk7886

3 ай бұрын

​@@kimtae858pretty sad really, the comments are great in videos like this

Feel like he’s just phoning it in

@WarwickAllison

3 ай бұрын

His joke is getting very old. But he'll keep doing it to generate all this pointless "engagement" as his channel goes down the toilet with all the other meme-chasers.

@WolfmanDude

3 ай бұрын

@@WarwickAllison Why are you so mad about a minor visual joke in the intro? Not even normal mad, your comment reads like you are about to strangle someone :D

@ionkill43

3 ай бұрын

@@WarwickAllison It's his microphone

@FrodeAltink

3 ай бұрын

No, it is not his microphone! His microphone is on the neck of his t-shirt. The phone is just a prop. And I am loosing my focus half way through the video because of that stupid phone. Please, just stop using it.

@WarwickAllison

3 ай бұрын

@@WolfmanDude Bored of it rather than "mad". Every KZreadr doing the same joke gets boring fast. I actually like that he's doubled-down - helps the meme run its course quicker.

To put the motor inside the gearbox you need to "cup" the motor with mounting points around the lip of the cup and the shaft through a hole in the bottom of the cup. Then you can put the bearings for the cam shaft around the cup. Or look for a motor with mounting points in the base. The size of this drive makes it kinda impractical, but it did lift 2 tons at 1 cm. Maybe going with 100% infill you can shrink the size a bit.

@erictheepic5019

3 ай бұрын

>Or look for a motor with mounting points in the base. Or he could *make* mounting points. I'm thinking either a battery spot welder or a (reversible) adhesive.

Giant open dog/AT-AT? Brilliant design!

The first cam which incorporated the motor was beautiful.

Having been watching you for almost a decade it makes me smile to see you learning and using mechanical principles. You've always been an amazingly talented electrical engineer with computer programming and maths skills beyond my abilities, but as I'm more inclined towards mechanical engineering then some of the earlier designs were sometimes difficult to watch. Nowadays though? Nothing but smiles! You've grown so much and you're getting so good at mixing the two specialties together to design and make incredible objects. Keep up the amazing work James! Thank you for sharing so much of your hard work, progression, information, knowledge, and passion.

@jamesbruton

3 ай бұрын

lovely thanks!

I love how everyone uses the time-tested "can't stop that with my hands" method to show that something is awesome and will be useful.

For your first design, the problem with your wobbeling is indeed with the motor itself, but not necessarily with gripping it. Essentially you have an overconstrained problem here. On one hand, the discs (through the frame and bearings) want to determine the center of rotation, and on the other, the motor wants to fix it as well. So what you would want to do, is release certain degrees of freedom keeping the motor in place, and only constraining the DOFs that you need. In this case, you would want to constrain rotation around the motor axis (otherwise the housing would turn as well), as well as translation along that same axis. You probably want to somewhat release the other two rotational degrees of freedom, although they are of lesser importance here. What is most important, is that you release the two translational degrees of freedom. That would allow the motor to 'self allign', and to 'track' the center of rotation. This would prevent the thing from wobbeling loose due to excessive forces, and likely also fix that flexing issue of the outer case. That second design, the belt essentially fixes this overconstrained issue. It is pretty compliant in those translational DOFs (and rotation as well).

I'm genuinely impressed it managed to do 200 NM for a moment and the only thing that "broke" was the belt no longer being tight enough.

@jamesbruton

3 ай бұрын

yeah

You can still have it in the center, just go to a larger bearing and make a casement that brings mounting points to the back of the gearbox (of the motor).

@TheGeniusSavant1

3 ай бұрын

That's exactly what I was thinking. At 3:48, it looks like it would be no problem to extend the sleeve and add mounting points at the back of the motor near the leads.

@leptok3736

3 ай бұрын

​@@TheGeniusSavant1third along the lines of: Was thinking, could he increase the diameter of the collar he puts around the motor to run some tubes along the motor back to a solid foundation? Then everything else is the same just with the center diameter enlarged to accommodate it?

A fun thing you might try with the phone is to swap the earpiece and microphone leads in the jack, and then speak into earpiece. It will sound more like what you would expect a phone to sound like. Its not the microphone that gives old phones that characteristic tone, its the speaker

@killingtimeitself

3 ай бұрын

its also the phone network, as well.

I think a simple thing that would make these projects easier is a big switch for turning on & reversing the battery power. You could even make it comically large, so you can throw it forward/reverse with lots of visibility on the camera.

Made my first cycloidal about 3 years ago... milled and 3d printed with servos... that thing was savage. But..... metal is metal! :) Excelent project tough!

I really love that something as simple as the belt tension can be utilized as the max lift safety-limiter to avoid breakage of other parts that would break otherwise. Go Open Dog!

Really love this kind of video that focuses on practical and fundamental elements James!

3d printed cycloidal drives always get me excited. I think they're going to play a major role in affordable robotics. One thing I will say about your design is that large bearings are expensive and heavy. I also get that sometimes you have no choice. Great video and I'm looking forward to what you're working on next.

"Assign a point of failure or it will assign one for you" -engineer somewhere

That is a monster drive. Keen to see the project that needs it.

Wow this may well come in use for one of my next projects! Thanks!

I'm building one of the Open-dogs right now.

@jessiejames3029

3 ай бұрын

post a video!

😊 very satisfying to watch cycloid gearbox drives 😊 💖⚙️💖

So Impressive, for a 3D printed cycloidal. Everyone who still thinks 3D printing Is useless, should Watch a James Bruton video

hello, you helped to inspire my senior design project in which I developed a 13:1 cycloidal. To reduce weight SLA printed bushings where used and they worked great!

What's with all the recent videos being phoned in?

@StyvynWayne

3 ай бұрын

@@MaariSuave- r/woooosh

@UptownBoogieDown

3 ай бұрын

Boom boom tsck

Bro I swear you have the bast ratio of skill, dedication and talent. Doing a couple of my own projects right now but definitely planning on making an open dog at some point. Keep it up man love your videos

@AJ-Palermo

3 ай бұрын

And creativity! He comes up with really intriguing ideas!

Increasing the belt reduction (if only a little bit) would also make the belt more tight.

Really committed to that phone gag..... :)

@filemorf

3 ай бұрын

More like :( getting old fast, find it distracting, I will be skipping ahead here and there to reduce my view time. Too bad I usually enjoy and look forward to his content. Hopefully just a quick fad of a meme and over with it soon. I don't want to keep talking about it either due to the Striesand effect.

@GooopGoooop

3 ай бұрын

@@filemorf imagine being this emotional over an insignificant prop

I love that solution for making an effective huge bearing out of plastic and small bearings

I enjoyed that immensely. Thanks.

I recently rebuilt a 4 tonne excavators final drive which is a very similar design to yours, but with a planetary gear set at the end, and three cam shafts spread out around the cycloid gears rather than a central cam to create that walking motion. The strength and reliability of these cycloid gear designs is incredible!

I first found your channel during the "Iron Man" period, and you never stop impressing me with what you are able to accomplish!

nice to see your still doin stuff

mind your wall thickness when you're designing those 3d parts. and use a inside radius whenever possible, carries the strain better than a sharp corner

I liked the circumferential bearing solution, using multiple smaller bearing held into a grove rather than using a single massive bearing or bushing. I’ll remember that trick going forward.

The most powerful 3D printed servo on the planet. Time to make BIG robots.

For 3d printing your big parts, i'd suggest a 3d infill like cubic or gyroid. It doesnt add much time and make parts somewhat isotropic and more tough

That poor-man's big-bearing seems like a good solution for the flexing. Too bad the back end of the motor isn't keyed for a better inlayed holder for that center drive idea to work but with the second version (including thinner profile & the guide bearings [poor-man's big bearing]).

I am vexed and flummoxed by the phone.

@jamesbruton

3 ай бұрын

I am speaking to you

If James Bruton was on Gilligan's Island the castaways would have been home by the end of the first episode!

A very nice build that's well explained, but I gotta ask... wasn't the intent to keep the motor inside the hub? I feel like about half-way through the video, the goal was kinda lost there. Might be worth re-tackling the original concept again, cause I'd still love to see a successful through-motor build.

I know so little about any of this, but I look forward to one day seeing you post a video about how you have made your very own Mech Suit.

you amaze me every time

120Nm?! From Plastic bits?! Are U MAD?! Cool gearbox, like the smaller bearings round the perimeter, I might S.T.E.A.L. that part of the gearbox in my own design. Not sure if that's more eco or just machining 5mm ball grooves between inside and outside housings.

is it possible that on version 1 one of the excentric 21gears was rotated 60° and thus the excenters are out of sync? (this sentence makes sense in my mind)

@furmek

3 ай бұрын

seems like it! The internal 20 lobed - 6 holed parts have only one axis (plane?) os symmetry. If you rotate them by 60 degrees of what the supposed to be you will start pushing outer "race" out of shape.

Hate that phone bit...

@Culpride

3 ай бұрын

If only the audio was consistent with it's use ... somtheing like "James lost a bet and now he has to use a telephone for on screen narraded clips." But this just seems to be a visual perturbance to artificially generate engagement.

Seeing it back-drive with the long lever arm made me think about a water wheel for generating power.

You seem to be still stuck on Hold every video 😁

wats up with this red phone? I dont get it! 🤔

@AnonymousAnarchist2

3 ай бұрын

Cant say why hes using a microphone inside a bright red phone, however I can say bright red phones have an association with important direct lines for a kind of neato oddball humor.. ish. I fail to find the humor myself but he seems to be enjoying it so.. meh.

Great work as usual.

@RGD2k

3 ай бұрын

I did wonder about changing the offset on the two cams from 180, to 180 - 1/4 * 1/21 * 360 (about 175.71 degrees), the idea being to stagger the two cycloids so the engagement/reengagement cycle is a 1/4 step apart rather than a 1/2 step apart. (quadrature rather than antiphase), which I'd hope would be almost as good as going three phase for getting the oscillating torque (and load noise) to be steadier.

That belt slip could be a safety feature, so your new entrance barrier (to the parking spot at your house maybe) wont kill anybody xd

Well done.

I'm surprised that James hasn't tried to build an RV Gearbox (rotate vector), which would be more powerful then just the cyclodial gearbox. I believe Nabtesco from Japan has the patents and is credited with the design. There are CAD models available from the Nabtesco website too. There are some very impressive capabilities of the RV gearbox.

@dennisdecoene

3 ай бұрын

If it's patented, then there is the answer, he does only open source.

@roseroserose588

3 ай бұрын

@@dennisdecoene patents only apply if you're trying to make money, if you're just doing it for fun you can do what you want (:

@tasa4904

3 ай бұрын

@@roseroserose588 Yes, but then he can't publish it for the public to reproduce without seeking permission first. Because he uses an incompatible licensing scheme.

10:15 - Because everyone knows PCB stands for “Please Call Back.” ☎️

I think what was happening with the first design was the gear was out of proper timing between the holes for the output bearing and the gear teeth. much like having to put the gear halves together so that the holes and the gear teeth line up, they have to be timed inside the outer gear so that they mesh properly with the holes lining up properly.

allowing the public to create their own customizable robo dogs is amazing.

(maybe bad) idea for improving belt skipping;- can you have the belt go around the pulley entirely? if you imagine that normally the belt is in contact with around half of the pulley, instead could you have a pulley that guides the belt to wrap around 1.5 times. Obviously, you'd need a corkscrew-shaped pulley so the belt doesn't clip through itself, and a belt that can flex that much.

@dekutree64

3 ай бұрын

Corkscrew pulley would cause the belt to travel sideways as it turns, so it would have limited range of motion similar to capstan drive.

@DariusAlexanderMusic

3 ай бұрын

@@dekutree64 excellent point, didn’t consider that.

Sweet! Now make a harmonic drive with a spline that isn't made of jello and a wave generator that doesn't just support the spline where the teeth engage!

If you have a method of measuring the concentricity of the motor housing to the shaft, you might be able to find why it was warping the outer ring. I think if you could constrain the cam shaft radially and just have a torque arm to prevent the motor from rotating, you would eliminate some tolerance stack up. But a torque arm would only work well if the motor was securely attached to the cam shaft (taper shaft or bushing) more than just a key and screw. Which isn’t really common for a 10mm shaft. But basically you reduced the number of axis you need to have tight concentric alignment by having a belt drive.

This is awesome

you need to drop the phone joke. it's through.

@GodmanchesterGoblin

3 ай бұрын

It's a joke?

You could always brace the motor mount to stop that flexing to allow you to take it higher before it flexes again.

I think we can drop the phone gag at this point..

That's a big servo! 😋

Wow, that drive is so impressive! I keep thinking it would be sweet to see you build a scale version of an AT-ST, that drive might work in the joints?

I love all of your videos. It would be awesome to see what you could come up with if you made a 6 DOF motion platform.

I like to see the mistakes and fixes.

The size of the 3D printed parts he makes scares my like a kid would when getting close to a steam locomotive.

8:49 So a slight redesign.... Leaping Lizards!

if you put a support bar between the motor on the shaft side and the center of the gear, it should keep the plastic from bending and moving the motor toward the gear, keeping the belt as tight as it is initially. it's really jsut a space that you might be able to put on/off, I don't think it'd have to be super duper sturdy to work, with the way it'd be arranged.

Brother, you are getting pretty blase' about putting your hands around highly geared moving parts. You really need to check yourself. This stuff is now getting finger mangling strong. You need new safety protocols.

@Hawk7886

3 ай бұрын

Yeah those pinch points would blow up fingers like hot dogs hit with a hammer

@The12gaged

3 ай бұрын

Ya. Ngl, even though I knew this was posted and nothing likely happened, I clenched when I saw that. It not being bolted down, with the self collision issue, while all the sketchy finger work was going on was a recipe if i ever saw one. Glad it went like it did.

@BouncingBallGames

3 ай бұрын

Ooof that was painful to watch.

@Fanny-Fanny

3 ай бұрын

I disagree. I think it made it more exciting

@mrwoodandmrtin

3 ай бұрын

Good point.. It's just a bad ROI in my honest opinion. Entertaining you briefly in exchange for the premiant loss of a very useful fingertip. @@Fanny-Fanny

You could make that a hands-free phone with a rubber band or sweatband like all the cool kids lol

This has to be one of the best projects on KZread right now, I need to learn more about programming.

Bring back open dog!

lol red telephone is getting weird

You're a gem.

nice job🎉

Nice James

OH YEEEEEEEEEEEEEEEES ANOTHER VIDEO OF CYCLOID DRIVE THANKS

you could probably put the belt side in double shear with one more plate. It would be nice if the motor had a longer shaft so that could be supported as well.

This guy is like einstein but with engineering in modernday

I am trying to figure out why he looks so incredibly good now

I can't believe how well that second one worked while still having the skinny ring. I've always proportioned them with OD = 1.5x disc diameter, whereas yours looks like 1.2x.Taking some rough measurements from a screenshot, I think that would make the solid ring (excluding the teeth) about 3x thicker, so 27x stiffer. Maybe I've been overdoing it...

So you have an rv gearbox, a planetary gearbox already mounted on a motor and a belt transmittion on top of it. I think there is some room for optimisation here.

I really appreciate folks that contribute significantly to open source technology development. So many smart and talented people do, and the world is way better because of it. I think the mentality people have to developing technology openly and collectively is a superior way of existing than the purely capital and greed driven alternative. Sure capital and greed driven projects have given us a lot, but had these been open source developments i think the world would have advanced much quicker. Look at 3d printers. It was only the expiration of patents that saw the technology really take off, and even though prior to that systems were available to those willing to pay, they were so few and far between and too prohibitively expensive that they really weren't the great contributors to productivity that modern 3d printers have become. Maybe i am wrong about this. I only know the pub science facts, but that is my take on the whole 3d printer patents thing.

Petition for James to buy a small 12V screwdriver 😂

hey james, i noticed how cleanly some of your parts fitted together and I was wondering what offset you would use for say fitting a circle within another circle? thanks tyson:)

I love that it's a compact gear reduction the size of a basketball.😂

i think in the first version one of the inner cams was a tooth off or something causing the output bolts to press them further out then the diameter of the housing, thus the flex

I'd be very interested to know how you design the belt sprockets! I have belts but no idea how to design the sprockets for them to run on.

Could you please do an episode on dynamically balancing things? Like a setup that measures amplitude and phase of vibrations and then computes what amount of mass to remove and where.

beast

What's with the phone?

You could replace the belt by gears in order to avoid belt skipping

Biggest servo horn i've ever seen 5:43

I'm curious if this could be a feasible option for something like a (relatively) slim high load elbow joint for a mechanical arm alternative to hydraulics. Seems like if it was made of sturdier material then it could move a heck of a lot for such a small setup. Either way looking forward to see what you do with it in the future.

I think you misaligned the disks in the first version, causing the wobble. Given 20 teeth and 6 holes, there should be 3 distinct positions for the disc relative to the other when mounted on the 6 studs. Look at the overlapping circles, they seem to be asymmetrical (as seen in 6:07)