Home
Creators
Search Recent Missing Random
Posts
Search DMs Popular Hash Lookup Tags Random
Importer
Import FAQ
Register Favorites Keys Review DMs Logout
Community
Telegram ThePornDude
Home Creators Posts Import Register Favorites Logout

Cycloidal Drive (version 1) (Patreon)

Published:
2021-03-08 10:14:00
Imported:
2026-06
haven't archived this post yet. have a subscription? use the importer!

Content

Here's next week's video, early for Patrons. This video goes out publicly on Tuesday 16th.

Yep - there's a new version in the early stages which will come up in a couple of weeks all being well. I really want to put it in a robot leg and make it jump on the ground a lot to test resilience. 

Files

Previews only

Experiments with Cycloidal Drives - PREVIEW VERSION

I thought it was time I did some testing for Cycloidal Drive Reducers for robotics, in particular my Robot Dogs. Belt drives have worked ok for me up to now, but I'd like to get a higher reduction in a smaller space. I'm trying to make something that is 3D printable and also reliable enough to withstand the dog stamping on the ground. You can support me on Patreon or buy my Merchandise: *************************** Patreon: https://www.patreon.com/xrobots Merchandise: https://teespring.com/stores/james-bruton *************************** Affiliate links - I will get some money of you use them to sign up or buy something: *************************** Matterhackers 3D printing supplies: http://www.matterhackers.com?aff=7500 Music for your YouTube videos: http://share.epidemicsound.com/xrobots *************************** Other socials: *************************** Instagram: https://www.instagram.com/xrobotsuk Facebook: https://www.facebook.com/xrobotsuk/ Twitter: https://twitter.com/xrobotsuk *************************** CAD and Code for my projects: https://github.com/XRobots Huge thanks to my Patrons, without whom my standard of living would drastically decline. Like, inside out-Farm Foods bag decline. Plus a very special shoutout to Lulzbot, Inc who keep me in LulzBot 3D printers and support me via Patreon. HARDWARE/SOFTWARE Below you can also find a lot of the typical tools, equipment and supplies used in my projects: Filament from: https://www.3dfuel.com/ Lulzbot 3D Printers: http://bit.ly/2Sj6nil Lincoln Electric Welder: https://bit.ly/2Rqhqos CNC Router: https://bit.ly/2QdsNjt Ryobi Tools: http://bit.ly/2RhArcD Axminster Micro Lathe: http://bit.ly/2Sj6eeN 3D Printer Filament: http://bit.ly/2PdcdUu Soldering Iron: http://bit.ly/2DrNWDR Vectric CNC Software: http://bit.ly/2zxpZqv Why not join my community, who are mostly made up of actual geniuses. There’s a Facebook group and everything: https://www.facebook.com/groups/287089964833488/ XROBOTS Former toy designer, current YouTube maker and general robotics, electrical and mechanical engineer, I’m a fan of doing it yourself and innovation by trial and error. My channel is where I share some of my useful and not-so-useful inventions, designs and maker advice. Iron Man is my go-to cosplay, and 3D printing can solve most issues - broken bolts, missing parts, world hunger, you name it. XRobots is the community around my content where you can get in touch, share tips and advice, and more build FAQs, schematics and designs are also available.

Comments

Thomas Messerschmidt

I like what you are doing with belted/pulley systems. I am still using servos directly hooked up to my robots’ appendages and suck, but I see all of the advantages of what you are doing with the dog’s legs. I suppose different belts have different compliance. Metal gears not so much! By the way do you ever read Servo Magazine? It is a great robot hobbyist magazine. They are publishing a series of articles of mine next month.

Anonymous

Nice. I'm surprised you didn't mill the cycloidal disc out of aluminium using your CNC machine for more resilience though.

Thomas Coley

I like this. As the bearings on the outside don't turn as much do you think using nylon sleeves instead would be as good and reduce the weight?

XRobots
>>55152564

The belts are really tight in openDog V2, so most of the compliance is actually the holding power of the motor on the 5:1 reduction - hoping to do the same with this reducer. I used to subscribe to Servo years ago, but I don't get much on paper these days!

XRobots
>>55153210

I'd really like to see what the capabilities of 3D printing are to start with, and so far the disc wasn't the part that broke ;-) Delrin or Teflon would also be a good option.

XRobots
>>55154088

Yep - I think that will be a conclusion of the next design due to cost and weight.

Scott Cress
>>55153210

This was my thought too. In the next version are you going to 3D print the replacement drive shaft offset?

XRobots
>>55153210

yes but it's much fatter with a bolt running through it and a bearing at the other end (and two discs 180' out of sync on it).

Anonymous

In the next video, can you go into how you mathematically design the cyclical gear in Fusion 360. I've seen a couple different methods and software used, it would be great to know what you ended up going with.

Anonymous

It looks really good! I'm excited to see what you can do with it! It is a bit hard to get a sense of scale, though. Before you put in the motor, it looked like the mechanism was around a foot in diameter.

Anonymous

In the last few recent videos you’ve tended to shoot the footage and then add voice over. It works but I miss the relationship with you James. The videos are becoming more like open university and I don’t get the same connection to the person behind the craft. I’m sure this current video production is faster but it’s not as warm as how they used to be. Just saying.

Anonymous

That was a thoroughly enjoyable video, The explainer on the cycloidal gear was phenomenal as well.

Anonymous

Super interesting. Looking forward to the next version and finding out how much torque it can produce.

Anonymous

I have found with cycloidal gearboxes the cost of bearings (especially the really large ones) really adds up. I had a project that I needed to make ~20 gearboxes and couldn't justify the $60 in bearings per gearbox cost. After working with this problem for a while I decided to use round plastic balls in the gearbox. Here is a link to a google drive folder with images of my gearbox. As you can see the gearbox is about 17mm tall and uses only 3 bearings. The gearbox weight is 68 grams. I wanted to share these ideas with you in case you wanted to experiment with this concept in the future. The pictured gearbox is like 6:1, but they are made in a way that you can pancake many ontop of each other to create different gear ratios. For example, I use (2) 6:1s together for a 36:1 final ratio. They work reasonably well. Also in the folder is a couple of images of a cheaper bearing concept that you could use instead of the more expensive wide ones. They use standard 6mm BBs. https://drive.google.com/drive/folders/1E1vPf-afmGg4hBSMjDaArSEWVRHxCQ2r?usp=sharing

XRobots
>>55165935

I'm not sure if I did it mathematically correctly. I just arranged 11 cylinder for he out teeth, and then 10 for the inner disc which seemed to be in the right place, then just merged the inner ones to a bigger disc and rounder all the corners off. Everything else was then based from the resulting cetre offset.

XRobots
>>55184584

The yellow demo gear was quite large, my hands were in it quite a bit though!

XRobots
>>55185375

I understand what you mean. I was trying to boost the view count which seemed immediately drastically different in the first few videos this year with the new format. The amount of the videos that gets watched on average is higher as a result of the change, but it will probably depend on the subject matter. I'll probably be drawing a balance once I've tried this out with a few more types of builds.

XRobots
>>55199378

If it doesn't break I think it will be pretty high. I'm also interested in general toughness when a robot jumps on the ground.

XRobots
>>55200539

Thanks for that. There are some cheap bearings available from China, but also metal is heavy, so I'm considering just nylon bushing for the outer teeth - like big Nylon spacers/standoffs basically.

Philip Brechler

Great idea but given the 3d print on-demand options most makers have available now couldn't it make sense to make some parts printable but from stronger materials, like Nylons or even metals?

XRobots
>>55221998

Hi Philip, thanks for your support! Yep - that's an option, but we'll see what the next weakest parts is that breaks next. I'm working on V2 now.

Philip Brechler
>>55221998

Thanks for the reply. I think extending the motor rod and having a counter-balancing disc is the right next step. I was just thinking that maybe limiting yourself to "traditional" PLA printing might be a limiting factor here

XRobots
>>55221998

We'll see how it works out, if it's built to work in PLA, then there's lots of potential.

Philip Brechler
>>55221998

Sure it would make Cycloidal drives way more accessible to makers. However the cost off bearings could become a limiting factor if many are needed to compensate for the relative weak material. But of course that’s a pretty hard balancing act and I appreciate it deeply that you go down this route

XRobots
>>55232747

That's the ultimate reduction - but it's hard to make the flex spline part reliable.

Jeffrey Cutler
>>55232747

Yup! He shows using a standard belt as the spline which I found interesting. You certainly are an expert at gears and belts these days! Love your work! The explanation of how the cycloidal system was very understandable. Thank you for all of your hard work.

XRobots
>>55232747

I thought that the spline was supposed to be coupled to the output which is always tricky.

XRobots
>>55232747

So the inside-out belt/spline is locked into the orange part which is the output. Then at 10:22 he shows the proper metal one which looks like a cookie-cutter - so the base of that is the output. It's probably possible to 3D print something in a flexible filament but getting enough force on the output without it slipping or bending is quite hard.

XRobots
>>55363899

Looks amazing, we're going to need stiffer legs before I can try anything like that though!