I tried to “cut the fat” for this video. More time went into editing, and I actually kinda enjoyed the process! Hopefully it made it more enjoyable to watch. Thoughts on a robotics arm using something like this design?

Bucket of water is a fairly accurate weight. If you don't have a scale, you can measure volume and use density to get a weight.

I find the cycloidal drives extremely interesting :D

This is so cool! Goes to show how much someone with a creative mind and relatively cheap tools can make...

Very cool design, and I love how you scrolled through the whole code to explain it as you went. Also, totally interested in seeing a robot arm made of these!

The OVAL PROBLEM in a 3D printer occurs because of one of the belts being stretched permanently. I faced the same issue b4, got it right by using a new belt

There's no proper word for the amount of joy that came up when i saw that this was printed on an MPSM

Going forward you may want to check Trinamic motor drivers, they drive motors with much more control that h bridges, and you they have evaluation boards that are affordable. Amazing work by the way!

If you tie a string on the end of your square tube and on the end of that tie a empty milk jug, you can apply a range of test torques by adding measured amounts of water to the jug.

You can scale the 3D model in the slicer by a very small amount (e.g., 1%), independently for X, Y, and Z.

6:45 what I did is buy a 8l water bottle, with that you can just fill it with water and use a kitchen scale to get the exact weight you need, its great for testing torque capacity at any possible weight

Awesome work , I'm looking to finish a five year project of my own and you have definitely helped me to understand several things that I need to take care of . You gained a subscriber .

This is awesome! I'm keeping my fingers crossed that this stays exciting enough for you that you keep devoloping it into something even more awesome and useful!

I'd give a pankake stepper a try... would make the build more streamlined. Brilliant idea by the way, looks very promising!!

Super cool! Robotic arm would be fun.

Great job. Yes make the robotic arm as that would just be fun to see and for you to do. A new printer even a cheep one sounds like a good idea.

really interested in the refined open source version!

Great project. Thanks for converting to metric units as well 👍

You should get a smaller glass bed for your printer. (Or even better, a PEI flexplate) That extra weight is sure to introduce more ringing than necessary.

Nice one!!! 😊 I did an inside out version of a Cycloidal Drive with a BLDC... it reduces noise and weight, while increasing torque and speed...but at the cost of needing an extra encoder and expensive mcu, so using available and cost effective stepper motors is of course a very good choice in this scenario too!!

Wait a second you're not Tom Stanton

I'm happy I just discovered this channel. Maybe a resin UV printer would make more accurate gears for this?

dude! awesome work! looking forward, would like to see the next stage!! :)

This is just awesome! I really appreciate your extremely well done videos and your objective way of looking at your own creations! Go on mate! Cheers!

Hell yeah! the Monoprice mini V2 my favorite of my 3d printers.

I like your experimental & fun approach to designing new things. Your 3D printer is a nice tool to have, allowing you to _"extrude ideas from your brain 🧠"_ 🤔

That's a great design. I'd like to see you do a whole arm.

Superb project! I had the same problems with squashed circles before I've tightened elastic belts of the printer.

Cycloidal drives are cool, but you have to know it's the reason you can't move the arm anywhere near the max holding torque. By the time you get an actuator on the end of the arm, you'll be close to your 2.5 lb limit. Increasing the teeth per inch will help a little, but a planetary gear will be needed at the shoulder.

I have a mini v1 and was able to fix an oval printing issue by tightening the belts. You should also ensure that the stepping values in the firmware are the factory settings. If they are not your scaling will not be consistent across all sizes of prints.

5:06 [insert me when X -joke here]

Been a while since I've seen somebody use one of those dual H bridge drivers on a stepper, had almost forgot there was an alternative to the little stepper drive ICs, especially the Trinamic magic ones. Wow, crazy that it's back drivable! I mean, not super smooth, but not talking worm gears.

The design of this thing is great! Amazing work!

Looks like a perfect chicken coop door opener/closer. 🤔

Nice job

Amazing work! However do not confuse a potentiometer with a cheap trimmer. Trimmers (like your blue one) are supposed to be used just for infrequent adjustments.

Really cool! I´d definetly like to see a finished arm using those actuators!

Backdriving is actually not a good thing for robot arm. At least not for most applications. The idea is that you should have big gear ratio so you would get hefty torque and no backdriving so if you cut the power the robot will not collapse. Great video anyway!

dude internet is full with free learning material and prototype projects .why should we pay you to look at the files ??? no offense

Hmm, maybe having seperate drive and position detection motors would be a good next step, to minimize the effects of stress and strain on the little plastic bits.

i think you could attach the potent to someone arm and be a sort of exoskeleton , maybe to help those having minimal arm issues

To the people who keep harassing him about his choice of units of measurement: Just stop. Use your own choice and respect his right to his choice. Nobody needs or wants your abusive expressions of your opinions whether they're overt, or transparently "subtle" like Mister "Accept The Scientific Language" down below. Grow up.

Nice project man! Although, don't get mad, the final result looks cooler than it performs: lots of play and it doesn't actually work like a servo (it is not positioning aware)

I have the same problem with my MP Mini. On my MP Ultimate (Wanhauo Duplicator 6) circles are perfect. What a great project, cant wait to see what you do next with that.

Cool stuff 😎

8:05 You need your printer tuned in really precise for minimal gaps.

I like the design a lot, particularly the holding the gears from turning and rotating the case instead. So I had a couple of thoughts that may or may not be feasible.: 1) to eliminate the bulk of the stepper hanging out the side, is it possible to mount the motor beside the gear box in the fixed arm and belt drive from there to the input of the gearbox? 2) expanding from 1. use a BLDC motor with a small toothed pully on the motor and a larger one closer to the diameter of the gearbox on the gearbox input. BLDC motors are lighter weight and quite often more powerful than stepper motors, I think that would make it a lot faster and reduce some of the noise a bit. :-) Great project, looking forward to the next one.

Can't wait to try this on my resin printer

Well done Levi!

Awesome! I've gone through a few iterations of a harmonic drive but I have not been happy enough with it to publish yet.

Just discovered your channel. Informative and well made which makes this an awesome video! Good job and hope seeing more 👍

Nicely done. Cycloidal gears are something I’ve always found interesting. If you wanted more precision and torque, you could use a worm gear system in a similar space.

The robot/motor community is so divisive about which units to use for torque. I believe that SI units are superior to imperial units, but kg cm make the most sense in the usual armature lengths we deal with rather than meters and usually thinking of loads in terms of weight rather than newtons. Anyways, team kg*cm ftw

4:00 Yeah ... the bottom and top part aren't really designed for 3D printing. If they were, they would forgo the size reduction. (brought to my attention from the rough surface which would be the side on the print bed if designed correctly)

CNC'd metal parts and a stronger stepper and I think you have reasonably compact and robust design.

Yes, the ovals are probably from your x and y steps not being calibrated. Search for e step calibration

Awesome Design Levi!

Looks great , Have you checked out Paul Gould's videos ? They looks very similar in design , perhaps a collab ?

Absolutely do more

This is not cycloidal or harmonic. This in literature is called the Circular wave drive. There are lots of information in literature and academia about it.

nice project, will CAD files be public?

Zig-zag a chain of them paired in a scissor formation all receiving the same signal acting a massive linear actuator.

Neat, looks awesome. Some of the play could very well be due to tolerances between the metal tubing and the screws. Threading on screws should never be used to center a smooth hole, only to clamp stuff together by lock into other threads. Maybe try shoulder bolts?

wow, the quality of the video is much better :D

Thanks for sharing! Cool project!!!

How about a worm gear? It would make the system a while lot stable when the worm on the motor drives the arm. The printed worm may collapse but a aluminium would be a good option.

This is incredible, subbed, thank you

Thanks for the metric torque!

Great work

Great design Levi ✅✅✅

Check different supplyers for printer stepper drivers, sometimes ( in 5 packs ) they can be cheaper than dual H-Bridge and cuts code to pulses ( steps ) and direction outputs making it easy instead of having a step table.

Nice work - I have a similar project underway

Very sleek design, it will be interesting to see the complete arm.

My Project for my BS in Engineering Physics is focused on the development of a 3d printed actuator. I've chosen a cycloidal drive for my design as well, they're great! If anyone one is interested I'd be happy to share my work!

It seems to me those inner cycloidal gears could be rotating slightly and that might be producing most of the play in the mechanism.

very cool

8:14 From the looks it isn't a cheapo device, but I see things that aren't done that way anymore, unless they are DIY or penny devices. Time for an upgrade?

Ewww freedom units :( Nice job man, very cool. Do you buy your bearings in the US or bulk order them from China or something? I haven't used ball bearings in years.

Perhaps leave it sloppy, but put a spring in the design to push or pull all clearance to one side :)

hello, definitively interested in a full robotic arm. before changing your printer better tuneup your pulse per mm/inch to get real circle. a second printer is always handy also...

What happens if you don't have the bearing but instead try some kind of greased sliding surface? I'm guessing the bearing is the most expensive, heavy and hard to find part. If a bearing free solution would work, it would make the design even more accessible!

2:00 Here you were talking about the pwm signal caused by the stall torque or something. I'm currently doing a project and I am trying to find the best way of detecting the stall in a simple nema17 stepper motor. Do you have any suggestions what the best way of doing this would be?

Lets suppose you obtain 7.34H*m of pulling torque (actually you don't as i can see, but whenever) with 25:1 gear ratio (as you mentioned in the comment section earlier) while motor nominal stall torque is 0.59 N*m (nominal pulling torque is less than stall torque, but anyway). As far as I can tell efficiency of the gearbox is something about 7.34/(25*0.59) = 0.49. Not so much even for 3d printed gearbox, but you could mention it because it is one of the most important and significant characteristics of the gearbox design.

Nice information, thanks :)

Is there are reason why you went for the justified but ancient L298, rather than a more modern Step-Stick A4988/TMC2208 or similar? Micro-stepping should help smooth out motion and reduce noise. The TMC range of drivers also offer silent operation. For robotics, you'll need some positional feedback, especially with steppers. A potentiometer at the very least. Optical encoders are better. There's a quadrature optical sensor available on a break-out board for around $3-5, and you can print your own encoder onto OHP slides or photopaper.

5:07 It's alive!

You would recuperate the angle in a register it would be more .

For a second I thought you were tom stanton

use a better driver. it will reduce the sound and will get more smooth movements

This looks awesome! I really like the design; it seems like the perfect arrangement for this kind of actuator. Hopefully I’m not out of my depth here, but I’m pretty sure stall torque and stall current aren’t meaningful concepts for stepper motors; they’re more for brushed DC motors. For steppers you have the hold torque, and the current is mostly based on how you’re driving it. In your footage, the current is the same with or without the weights, and the extra noise is probably just a mechanical thing. Since a stepper motor doesn’t provide feedback (and often isn’t used with it), and it’s speed/current is not inductively limited, it can’t react to increased loads. There might be more going on behind the scenes, and you just simplified it for the short video, which is nice-and it was a good watch! But if you want to describe the behavior of the actuator better, I think you would do that by citing the rated current for the stepper (or whatever you chose to drive it at) and measure the slip and hold torque, and maybe also the unpowered detente torque. Anyway, thanks for the video, and again, awesome design!

I suppose taking a minute to explain how a "cycloidal drive" is supposed to work for those who have no idea what it is supposed to be was asking for too much. S'okay, I'm sure there's some other channel I can subscribe to instead that does actually do that.

I really want to see you build a robot arm with enough torque to lift you

I have built a robotic arm with a similar cycloidal drive design, but one of the significant shortcomings of this mechanism is it cannot transfer a higher amount of torque, as shown in the video; when you try to move at higher loads, it starts slipping in the same way. @LEVI Janssen, do you have any solution for overcoming this slipping issue? It cannot be done by using a motor of higher torque as the current motor I am using has high torque, but the gearbox starts skipping at half of the motor's rated torque.

Amazing design!

There is little difference in additive machining and subtractive machining except cost and accuracy. Have you thought about making the gears from a metal that was cut on a CNC mill for instance?

Good work friend.. Could you please shared the dimention of CAD drawing

Very impressive. Well done.

Hmm... Is there any specific reason you used a H bridge to step the motor yourself instead of using a regular stepper motor driver? I mean, I'm all for doing stuff yourself, but only if you can actually do it better than the store bought version. And in this case I think a silent step stick would have been a big improvement. Anyway, I like how compact your gear design is. It's pretty neat. I designed and printed a robotic arm a few years ago. And it used pulleys to drive the individual segments. Which was kinda annoying to do since it was hard to try and hide the pulley system. It had the advantage of dampening the vibration caused by the stepping from the driving motors. It wasn't as compact as your design though. I'm wondering if a planetary gear would be better suited for your design when it comes to delivering torque... I figure one could link a few stages together in a joint in order to increase the torque as necessary. What do you think?

I am curious to see a robotic arm made from this cycloidal actuator. Can it be used for precision work like motion control, welding etc.

Good job,thank you for sharing ,if you cosider practicality/ease/aesthetic you get good grade for it ,need to work on precision/backlash