On my Jointer/Planer combination machine I had to crank the table all the way up and down if I switch the machine, because the dust shroud has to flip under the cutterhead. I replaced the Handwheel with a 1.2Nm closed-loop-stepper. Controlling it via Arduino and the huge advantage of the closed loop stepper here is: I also have a display connected that shows Theoretical Position to 0.1mm. And since the stepper doesn't lose steps, I can really count on that. I essentially have a digital readout with position control (normal and fast travel and a 0.1mm button). Now I don't have to hand-crank anymore, its way faster to switch the machine around, I don't have to bend down (The button is higher up than the hand-crank) and the machine is also way more accurate. The original scale was 1mm accuracy. Now I can thickness down to 0.1mm accuracy - repeatably!

I used closed loop steppers on my home made CNC router, I couldn't be happier with the way it performs and it was so easy to do.

Used to use those on home built CNC machines . In the past you had to buy double ended stepper motors and add the encoder to it. They have fallen out in favor of DC servo motors now. Much cheaper and easier to do this stuff now than it was 15 years ago. And steppers are far stronger today than they usded to be.

You can get NEMA planetary gearboxes that will fit right on the end of that stepper for a bunch of extra torque Your speed seems high enough to still have it operate quickly enough

6:55 another option is a stepper controller with a build-in motion controller, f.eks. tmc5160. You just tell when to go and how fast via SPI or UART and it does all the ramping. As long as you don't to synchronous the motion of several motor, like for a CNC, they are easy to use

Oh man more homework for me now. This might solve several challenges I have with traditional stepper motors in my projects. The additional cost is a pity, but might be a non issue due to the additional complex scenario accuracy. Thanks for making this video.

I've used a brand of closed loop steppers, ClearPath by Teknic. They allowed for tuning once mounted and all hardware was attached so they could run at their fastest. They were pretty cool to work with.

Looking forward to seeing all teh projects with these stepper motors

Nice to see you discovering the "joys" of closed loop :) Be carefull though and safety first :)

Never get here this early. Happy you got your channel back so quick. Really good video. Might be interesting to see these closed loop motors in more "compliant" uses. But would need to overcome the "out of sync" failure. Might be better to have a seperate encoder and handle error correction in the microcontroller.

9:07 - for a rougly the same price (little bit higher) you can get an integrated step-servo in nema 23-24 size. same performance but with 2-3Nm torque. look for IHSS57 type. as for terminology - "servo" is not a motor type it's a drive type. so any motor with closed loop control is a "servo". closed loop AC motor - AC servo, closed loop DC motor - DC servo, closed loop stepper motor - stepper servo. saying that servo is better than stepper is incorrect because stepper can be a servo too )

Thank you. So much quieter too. This is incredibly useful and I'll be buying a couple of these in the near future. I'm capable of goggling "closed loop stepper motor". I wouldn't mind buying them from an affiliate link tho...

I have no knowledge about electronics and motors but it's still enjoyable and facinating.

For a single motor: this form of closed loop steppers is great. For any multi-axis CNC, the "reaction" time means that the absolute position of the end effector is unknown, as the controller on one axis may already be there, while the other is "making up missed steps". Tracing an arc (for example) with two of these, when pushed anywhere near their limits, will result in inconsistent and difficult to reproduce behavior.

I love your videos Matthias!

Great video, thanks for sharing what you learned!

I like servo steppers, they are a bit more expensive but they are easy to use and perform very well.

from a controls perspective its still a good idea to provide higher order motion profiles in closed loop control systems due to higher order vibrations in the rest of the system if you have a more complex/sensitive system. It will also limit overshoot and such, though I am curious as to how these steppers have their controllers tuned and if you could change them to adapt to your given loads/motion profiles.

That fun little Pi heatsink looks like it's about to take flight!

My current project involves closed loop stepper motors with a discrete driver, but I'm tapping into the motor's encoder signal with a microcontroller timer peripheral so that it always knows the position of the motor, even when it stalls. I want to avoid the condition that you demonstrated where the motor stalls too far into the "overload" range and the driver shuts down, then needs a power cycle to recover. I'm just having the microcontroller send steps in the direction of the stall to keep the driver outside of the "overload" range. So far I've been testing with a 4 Nm NEMA24, but I just got a 12 Nm NEMA34 to evaluate... That thing is a beast!

I upgraded my CNC machine to Teknic Clearpath SDSK closed loop steppers. They’re cheaper than servos, but they can be driven with 5V signals. They do require separate 75V DC power supplies. My machine is WAY more powerful and performant, and it doesn’t lose steps. If I have a crash and it does, the controller gets feedback and stops. There are other versions of the motors and they’re easy to control using a Raspberry Pico with PWM or frequency positioning. They’re just amazing. I have some videos of my automatic height dustboot that uses one of those.

Yes doing small+deep on a CnC is tricky, but you can make many very precise thin gears and glue them together

great explanation and demo, thx!

Mathias, there are stepper drivers that support non-realtime interfaces. They are usually expensive and designed for industrial or CNC systems, though. I'm sure someone has designed and developed a nice hobbyist grade one out of a cheap micro-controller, though. Being able to send "+500 steps at 300steps/second" over i2c or uart and then not having to worry about timing would be really nice.

how have you not build your own cnc yet, with your programming skills and everything the sky is the limit :)

ooh, super excited about this subject. These have really improved and come way down in price in recent years.

Those with a magnet, have a Hall effect encoder. 12 -15 bit so more accurate than most optical.

Now you need to hook that up to your box joint jig

I think we all wish you had a cnc AND a 3d printer. Not because you need them to make things obviously, but because the rest of us have to rely on those things for our projects. If you had those, I can only imagine all of the awesome things you would discover and share with us about making them work better :)

Very interesting! The closed loop steppers look like a real winner. BTW, I've used magnetic encoders with FRC robotics and they can resolve 4096 counts per revolution. That may be better, actually, than what the optical encoder is giving you.

I have these closed loop steppers on a Farmbot that I purchased in China a couple years back. Talking with the supplier, he told me that they were looking to replace the stepper motors and the Farmduino with RS423 closed loop steppers. Via RS423, the stepper can be told how far to go and it will just go there. Under certain circumstance these seem useful but there are bound to be some limitations.

Clearpath SD nema 34 are a beast. I have them on my CNC

For many high torque applications I use Geckodrive DC servo drives. These allow me to repurpose large DC brushed motors up to 80 VDC and 20A. In most cases you have to build your own encoder or a mount for a commercial one but after you figure out how much resolution you really need usually a very simple encoder will suffice. Often I 3D print my encoder assemblies. Industrial motors often have fans that can be removed and the space used to install encoders.

LOVE working with Clearpath closed loop servos. Fast, quiet, strong and onboard software and monitoring. Would never go back to steppers.

You can get stable semi-realtime outputs on the Pi if you leverage the chip's DMA functionality. A few years ago I toyed with the "pigpio" library. It lets you create waveforms in software and then the hardware plays it back with perfect timing even if your code gets delayed for a few moments.

The magnetic encoders can work really well, and commonly have resolution ranging from 14 bits (16384 cpr) to 21 bits (2M cpr). Step loss correction vs field oriented control is entirely decided in the firmware, and I've used the magnetic encoders to great effect in my own projects with field oriented control. I think the closed source firmware for the super cheap mks stepper servos is likely the biggest problem with them, not the encoder.

When i went with closed loop on my CNC i had the issue where i had 1.5m long 16-20mm ballscrews attached to it with rigid couplers (after ripping apart flexible ones several times) and it caused a bad feedback in the pid loop . usually you turn the ball-nut at those lenghts but the design didnt allow for that. It became a huge torsion spring that makes the PID loop freak out and screams like its never seen grease in its life at certain feeds.

Could you provide a link to that closed loop stepper? I have an application where it would be great if I could just use a Pi rather than an Arduino + separate stepper control.

Fascinating!

I believe the ones that detect back emf instead of optical are also more efficient, since they can tell how much force is on the shaft / magnets instead of just position and can output the exact amount of power to counter act it.

When in proximity with machines with large motors (high magnetic fields) and noise (VFD motor drives), you may find optical encoders are preferable. Both will need careful positioning, cable routing and magnetic/electrical screening to avoid spurious behaviour. But they are excellent tools

I appreciate that you make things by hand rather than CNC.

Stepper motors are fine for the gruden implementations, where it doesnt matter where something ends. And compensate something with just more power. But these computerized allow so much great things be done in modern era... These are fancy tools for DIY for future creators.

Would love to try a motor like that some day.

I wish my rear wiper on my car was like this, and not slowly "progressing" towards downward position throughout the years.

Some of the closed loop steppers like servos can have an autotune feature where they can learn the kind of load they are powering and self adjust to a pretty good motion curve.

Very interesting! I wonder what could you be building to use these? I guess we shall have to wait 🙂

The wheels on the stepper go round and round

That looks good, I was working on a robotics project and had the same issue, the only issue with optical encoders is the stepper doesnt know where it is when powered on, I was going to try using a hall effect encoder which would know the angle at all times, but not got round to finishing it.

Excellent walkthrough of the closed loop stepper motors. Could you provide a link for the motor please? As you mentioned options for the motor are kinda confusing.

You might want to look into the Odrive, its an open source brushless motor controller designed for use with encoders, it supports up to 100A so you can get a crazy amount of torque and speed for not a whole lot of money.

9:39 I believe those controllers run real field oriented control, the magnet sensor output a 12bit absolute angle

regarding the closed loop controller that use a magnet glued on the shaft, I do not see any issue with that instead of an optical encoder. Those hall angular sensors have much higher resolution and speed than the usual optical encoders.

Used a lot in 3D printers/CNC machines

we should get a "stepper killer" vendor to sponsor you with some motors

I’m now waiting for Wooden CNC..

Man, I wish these things were available when I converted a mill/drill into a homebrew CNC. It would have made things quite a bit easier.

Do I have a project in mind for this? No. Did I just buy one anyways? Yes.

This is actually the first closed loop stepper I've seen with a stepper driver built in 🤔 Normally they all need a separate driver

i've been looking at using CHEAP motors with glass scales, interfacing them with the cnc controller is an absolute pain without spending much bank on a mesa card. so, for semi-auto drilling, i've had to brush off the old ttl circuit design files in my faltering memory. just today struck on the idea of using digital comparators with bcd counters and old fashioned 74ls74 d flip flops to read the encoders, the trick i've thought of is using a target count, a count from the scales, then using the comparator outputs, which are 4bits per, to control the speed through a switched resistor network. i've got a dro waiting in my jungle site cart, my design will probably be more expensive if i sold it in small amounts, but pretty interesting for the other weirdos out there, or for those that want to learn ttl, for some odd reason, many use arduinos for such a simple thing, but hardware works fine.

Do you have a link to where you bought these And could you also talk about the dip switch settings? Lastly, I am so glad you recovered your channel so quickly, I was very sad to see that notice on your second channel! I have been watching for years and love this channel!

Very cool

Are you going to put one on your screw advance box joint jig like it was originally? Maybe put a pneumatic piston on it to push it through the saw.

4:55 As far as I know, stepper motors (like Nema) can get really hot with no risk of failure. I don't remember exact values, but it can get hot that you can't touch it and it still should be ok.

5:25 I think that that makes sense, you are asking to perform a greater work, more torque, and either lifting the weight or lowering it is pumping the coils to lift or brake.

Can you link to the closed loop stepper motor you got please?

This is what love must feel like.. PLEASE be a reasonable price..

The motor and drive integrated closed-loop stepper motor in the video is produced by our factory. Please consult me if you need.🎉

Can you please evaluate a similar integrated servo?

+1 for pliers hammer at 7:57! 😄

Actually, I think this might be just the solution I've been needing without knowing it. Been wanting to make a pet feeder that was both accurate and reliable but also simple. And the drive system always turned me off. Not satisfied with simply running a brushed DC motor for a specific time. I think a Nema 17 with a similar control scheme to this one would check all the boxes. Provide feedback if the mechanism jammed. Could run on an ESP32 with no quirky issues and no extra components!

It's not that difficult to CNC gears though, just use a 1/8" bit or even smaller bit. The fillet that it gives in the inside corners you can transfer to the larger gear as well and the outside corners for it to mesh properly. But still, your band saw technique still beats a cnc for speed for a single or a few parts what with having to cam, setup/clamp stock and cut and sand the part. CNC really comes into its own for repeatability, 2.5D/3D cutting and larger numbers. I bet if you add a few more gears with a higher gear ratio, that small servo can pull more weight than the stepper motor and do it faster too since it can spin faster and torque at higher speed will improve. But it's no good as a 1:1 replacement. Servos (or the servo controller) can have tuning software to adjust the control loop so it doesn't overshoot/oscillate under certain loads. It's always a trade off of course.

Hey Matthias, I've noticed that you've been making a lot more projects related to automation lately. Do you think you'll ever build a CNC or anything similar?

Yeah, when you get a stepper motor out of synch, basically you'd have to realign it as with a standard floppy disk drive (but not the more modern kind like Iomega Zip and Clik!). My dad used to have to take our Commodore 1541 over to the shop to realign the drive, but then we got 1541/1571 Drive Alignment and I could follow the relatively simple directions to realign it myself even as a mere kid.

I’ve been using motors from Lin Engineering. Similar but commanded over serial.

"I can just treat that like it was a stepper motor..." Of course; that's because it IS one.

The question we all have Matthias is, what are you cooking? We are all eager...

A future cnc machine video is in the works?

Hi Matthias, could you share the link for the motor? Thank you!

just buy a 12Nm one, they are pretty cheap, planetary gearboxes are pretty affordable too, and almost no backlash when the driver faults out, you can re-enable it by cycling the enable pin, no power cycle needed

Very interesting motor indeed, Matthias! 😃 But I wonder about sensored brushless motor, how they work. All I know is that they're used for pretty expensive rc cars. Anyway, stay safe there with your family! 🖖😊

Did you have to write anycode specific to rhw closed loop logic, or did you just use the connections from the R232 connector to the driver A+ A-, B+, B- ?

what if you used a wood gear reduction, how much newton meter advantage could you potentially get?

If you are interfacing with any sort of real world hardware, especially hardware that could become unsafe then you really need to be using real time control. You shouldn’t really be shying away from using microcontrollers, even with the closed loop drivers you will still be better controlling it more precisely through an MCU. It’s also really not that much extra work to use an MCU for a relatively simple interfacing application like this where practically all of the calculations can be done on the pi. Setting up communication between the pi and MCU is easy, regardless of if it is UART, I2C, SPI, etc. If you have difficulty using an MCU in your projects and find it annoying or a hassle or that it makes the project more complex then you likely don’t have very good organisation of the project. If you know what you are doing then using a microcontroller in a project like this to drive the steppers should be easy. It’s all very well saying that if the pulses are 10 ms late then it can just jerk and catch up and that you don’t need precise motion curves but that doesn’t work as well as you seem to think it does. That 10 ms delay would be enough to throw the stepper out of sync in the first place (due to inertia) and likely isn’t great for the stepper or drive circuitry due to potentially high current spikes (in those 10 ms the closed loop driver could try and stop the motor, leading to a high acceleration on the motor and high current). For any project using multiple steppers this is totally useless, if your motor control signals are lagging or inconsistent then your system won’t work as well as it is supposed to and at the very least your movement won’t be smooth and you could have artefacts like ringing. You also still need to implement motion curves when using closed loop steppers or you will get bad results, both electrically and mechanically, suddenly stopping or starting the motor leads to high forces and high currents, the high forces can cause issues with things like ringing and resonance and just puts more stress on the system compared to a smoother motion curve.

Those closed loop steppers really are quite impressive, do they have the ability to output the encoder signal or have a real time positional data feed? This would allow dynamic tuning of motion profiles with the right software.

Have you tried Trinamic's stepper drivers? I've heard great things about them. They seem to make steppers "kind of" closed loop by measuring currents, and they can detect missed steps and stalls.

a closed loop stepper and a brushless servo is essentially the same. The advantage of a closed loop stepper is higher torque at the cost of lower max speed so you might be able to skip a gear

Maybe you don't want to endorse a particular brand, but a name and/or link for these would be appreciated, thanks!

@matthiasrandomstuff2221 Sorry if you already wrote it somewhere, but I cannot find the reference for the motors you are using and where to buy them. Thanks,

7:58 Ahh, pliers - the other hammer!

I have one of those hammers 😂 Good video, thanks.

up next: Matthias builds a CNC!

Nice as long as you only need one of them. As soon as you need two to coordinate PRECISELY which one is where when (such as any X-Y CNC mill/printer), you're SOL.

The cheap boards with the glued magnet, uses the same encoder chip as "proper" servo's, it performans about the same, its more janky though.

9:00 .... I think that if you used a large pulley and a small pulley on the motor instead of the gear, it would make the motor more torque

Can you gear 3 together to get some more power from them?

Can you post the closed loop stepper you used?

Great video! Would you share a link to purchase the motor? Thanks!

does your strength tester take a picture when it fails!? I see image @8:13

We use these a lot in industry, way more than steppers with an external controller. Specifically, AMCI SMD motors. All you need to use them is the motor, a 24VDC supply, a 5 core power cable and a 4 core ethernet cable. Just avoid programming them with Studio 5000, it's simply a chore to do anything with that program with steppers.