Take it from an EE who has developed from scratch and sold multiples of over 5 industrial robotic arm models. You are 100% right on not using stepper motors. Stepper motors are overrated frequently by hobbyist, amateurs but as a professional i don't touch them with a 100 foot pole. Pun intended. They don't have the I*Kt to deliver constant torque. I saw your etch and sketch video and a lot of the issues you ran across are already solved problems. But I guess that was the point of the project and the video to get to know and present to people what the state of art is.
What really is the problem with steppers though? Do you think if the commutation was just synchronised better and higher sample rate controllers did the switching at an appropriate timing, along with an adequately designed rotor/magnets and stator/coils would perform as good or better... Perhaps? Would adding another set of magnets and coils on the same axle, at an offset.. to compensate for the time the coils would have to be off. And evening out the duty cycle to occupy the entire spectrum make the torque more consistent? If so that's a pretty good idea ain't it?
Oh and I'm talking about axial flux, plus I'm thinking of using the entire stator worth of coils all at one, i.e commutating them. Then to smooth them out, just putting another set of stator and magnets on the same axle/stator/rotor. Just a small distance apart, slightly off a few degrees off phase. Such that 100% of the time.. a whole lot of copper would be used to turn the rotor? Would love to have a validation on this.
Absolutely wonderful video! It was informative and entertaining. You did a great job breaking down complex concepts so someone like me with limited electric engineering knowledge could easily understand.
This is a really informative and impressive video. Thank you for taking the time to present what you learned in such an accessible format for everyone to benefit from!
This is true engineering, an engineer doesn't always know everything down to the last details, but a true engineer can apply their math skills and **learning abilities** to study and understand the details of the problem they're faced with and the solution they're undertaking. It's fine if you don't have the full knowledge of a specific topic, but you must have the respect for the subject and study it.
@@EveryFlavorRobot it was honestly one of the best engineering related UA-cam videos I've watched in a while, you not only handled the criticism with grace, but came up on top after! respects!
Can you do a video of this same style about resisters voltages and capacitors I'm having problems wrapping my mind around them and your video formating is amazingly comprehensive and easy to follow!
@@TheaMakes interesting, perhaps we should clear up some misconceptions that we remember working through when learning those topics and maybe do some experiments to test some things we are still in the way to learning... I'm glad you liked our explanation of stepper motors!
@@zebedie2 our MotorGo board that runs the etch a sketch in this video is a custom BLDC controller that I made a few months ago! We are still developing it so that exact version isn't online yet, but everything we make is open source :))
@@LoganDark4357 did you know our bldc etch a sketch is a custom BLDC motor controller? Stay tuned, we will be releasing the design with our next video 🤠
I have a bunch of brushless motors from DJI s800. I've been thinking about turning them into servos. I'm just waiting for a more practical option to control them. They are outrunners. I'd like to design a housing for them with cooling considerations. That would allow it to run inside a gear box.
This video covers the basics of steppers. But you don't really talk about why and when to use steppers vs closed loop. Generally speaking. Closed loop BLDCs will outperform steppers in every category. Speed, accuracy, acceleration, power, efficiency, size, etc. But if a stepper motor is "good enough" for your application, it's likely that using a stepper motor is cheaper and easier than a BLDC. Generally, if you don't need high speed, efficiency, high acceleration, super high positional accuracy, and small size, a stepper is the solution.
@@gizmoguyar good point, I could have summarized it better I think. For me I genuinely didn't have an intuition for what "high speed/ low speed", "high acceleration", or "small size" meant in quantitative terms so I just tested it out real quick. Then I thought it might be useful to show some maths for the upper bounds of motors in general. Thanks for the feedback, summary, and for watching!
I understand using premeires to generate hype, but i get the notification for the premeire being announced, but not when the actual video is available.
@@skyslycer no you're on the right track. To give them the best possible chance, you would want to find the motors most efficient speed and gear the system such that you're using that speed. Ultimately we didn't go through the effort because we can see that the maximum power (assuming all was converted to perfect mechanical power output) was still not high enough to compete with our bldc motors. To do better we should use larger stepper motors, but at that point it becomes unsightly hahaha
@@thomaskletzl6493 so this is a bit I couldn't fit in the scope of the video - but there are two limits to the "maximum current/ maximum torque" 1) for stepper motors of this style and materials, you will reach something called flux saturation. Reportedly close to 2.5x the rated current of these style motors, though I haven't tested it. This is essentially when the increased current will not generate stronger magnetic fields at a useful rate. You also risk demagnetizing the magnets at this range. 2) as you mentioned the thermals are an issue, and with stronger cooling you definitely can push motors a bit past their "steady state". However, Nema 17 motors are traditionally closed off and your only cooling option is through the case. Ideally you could force convection through the windings themselves.
@@EveryFlavorRobot do you have infos on how much microsteps is usefull? My drivers could go to 256x currently im on 16x i have no idea what is usefull and what not
@@thomaskletzl6493 ok so this totally depends on what system performance you need, but let me try to give advice: Concern 1: noise - you will probably notice substantially quieter motors at 32 uSteps and probably won't notice much quieter past that. Concern 2: processor speed - if you need a max speed and have to set it with step and direction pins, keep in mind it will limit you if running on a slow microcontroller. At 256th uSteps that's 50k+ steps to command PER ROTATION so at high speeds that could get spicy for small microcontrollers without hardware timers Concern 3: accuracy, especially under load - stepper motors are designed to fall into "cogging" detents to ensure accuracy. Realistically as you increase uStepping you lose accuracy in exchange for resolution of electric field angle. What you will see is a lot of "magnetic backlash" as your motor will fail to move between uSteps. Because of this, I've never seen above 16 or 32 uSteps used correctly. BUT there are cases when you could find them useful. There are also stepper motors that are wound specifically for high res uStepping - these will perform differently because they are wound and designed to reduce cogging, which will reduce their powered off torque as a trade-off. Hope that helps! Good luck :)
@@samm7716 using stepper motors for closed loop is interesting! We did a little testing and didn't find a way to fit it in the scope of this video but we could do more in the future. Essentially however, this is a commutation improvement. Keep in mind that the max speed and torque will still follow Lorentz and Faraday's equations. Commutation can just help get closer to that! When we tested advanced commutation on steppers, like FOC. We discovered a few things: 1) you need extremely high precision encoders because the motors have effectively 100 pole pairs. This means that for each of those ~3.6° segments, you need enough data points to calculate the best field angle to drive. Only during those points calculated will you get improved performance. 2) you need extremely fast clock cycle on the computer driving the controller. This is because of how many field updates you need to send, unless you have a hardware generated sine wave. Our max speed was limited by our calculations which was disappointing and didn't do it justice. 3) the gains in efficiency aren't nearly as cool as in a low pole pairs motor, especially when considering micro stepping. This is because micro stepping is already approximating a sine wave quite well 4) most unfortunately, FOC commutation like SVM can sometimes make more use of the voltage range for a motor but not for stepper motors. This is because the phases are 90° out of phase and thus are already maximally using the voltage range. Tldr; we tried and it was disappointing and gave up, but may try again in the future!?!?
please do, I really liked the style and content of this video, and it felt like the topic of closed loop servos explained in this style would be a great video to watch, atleast for someone like, no one talks about, how bldc and steppers are kinda similar in this regard
Ideally you would gear any motor down or up such that it's operating in its most efficient speed and torque. We didn't want to change the etch a sketch robot so we kept it at the reduction that was available to us 😅
your bargain bin amazon steppers ain't the best, LDO, Leadshine, Moons all make some pretty good steppers, the key thing you wanna look at is torque curves, a simple way to get usable speeds for your motor, I can recommend LDO 2804s and 2504s, lots of high end DIY 3d printers use them. (annex k3 for example) That said BLDC servos will be faster often times.
Very true, some day I will do a comparison of high end stepper motors because I am curious about them! I bet with thinner laminations and stronger magnets and smaller air gaps you can make some serious improvements! However that said, I WAS comparing them against bldc motors that I got from AliExpress for 3.99usd - so roughly the same price point as these (which I stole from an ender3)
Super nit-picky but please please oh please set your voiceover audio to mono 😭 It sounds like you're dancing around inside my head lol Especially at the beginning
Do y'all want more content about motors?
This was better than all my time doing an electrical engineering degree
Great vid! I learned more about stepper motors!
Thanks Wren!! Making this video taught me so much about them too 🤠
Take it from an EE who has developed from scratch and sold multiples of over 5 industrial robotic arm models. You are 100% right on not using stepper motors. Stepper motors are overrated frequently by hobbyist, amateurs but as a professional i don't touch them with a 100 foot pole. Pun intended. They don't have the I*Kt to deliver constant torque.
I saw your etch and sketch video and a lot of the issues you ran across are already solved problems. But I guess that was the point of the project and the video to get to know and present to people what the state of art is.
What really is the problem with steppers though?
Do you think if the commutation was just synchronised better and higher sample rate controllers did the switching at an appropriate timing, along with an adequately designed rotor/magnets and stator/coils would perform as good or better... Perhaps?
Would adding another set of magnets and coils on the same axle, at an offset.. to compensate for the time the coils would have to be off. And evening out the duty cycle to occupy the entire spectrum make the torque more consistent?
If so that's a pretty good idea ain't it?
Oh and I'm talking about axial flux, plus I'm thinking of using the entire stator worth of coils all at one, i.e commutating them.
Then to smooth them out, just putting another set of stator and magnets on the same axle/stator/rotor. Just a small distance apart, slightly off a few degrees off phase. Such that 100% of the time.. a whole lot of copper would be used to turn the rotor?
Would love to have a validation on this.
Stepper motors are overrated by hobbyists, and underrated by industrial engineers. That's the truth of it.
there are all these Etch and Sketches, where my Sketch and Etches at?
And don't even get me started on the sketch sketches and the etch etches
@@EveryFlavorRobot They're all really sketchy tbh. Even a bit etchy
Absolutely wonderful video! It was informative and entertaining.
You did a great job breaking down complex concepts so someone like me with limited electric engineering knowledge could easily understand.
Thumbnail looks sick🔥
thanks! I had a little fun in photoshop with it ahaha
This is a really informative and impressive video. Thank you for taking the time to present what you learned in such an accessible format for everyone to benefit from!
I'm so glad you found it useful!! I personally loved making this video
This is true engineering, an engineer doesn't always know everything down to the last details, but a true engineer can apply their math skills and **learning abilities** to study and understand the details of the problem they're faced with and the solution they're undertaking. It's fine if you don't have the full knowledge of a specific topic, but you must have the respect for the subject and study it.
Aw yeah you get it 🤠🤠🤠💪
@@EveryFlavorRobot it was honestly one of the best engineering related UA-cam videos I've watched in a while, you not only handled the criticism with grace, but came up on top after! respects!
Can you do a video of this same style about resisters voltages and capacitors I'm having problems wrapping my mind around them and your video formating is amazingly comprehensive and easy to follow!
@@TheaMakes interesting, perhaps we should clear up some misconceptions that we remember working through when learning those topics and maybe do some experiments to test some things we are still in the way to learning... I'm glad you liked our explanation of stepper motors!
YAGVOS - Yet another good video on Steppers. Well done. The commutation explanation was genius!
Thank you!! (Love your channel btw)
@@EveryFlavorRobot Thanks!
If you want a BLDC servo then the closest option is a moteus driver for open source. There's also odrive but they've gone closed source.
@@zebedie2 our MotorGo board that runs the etch a sketch in this video is a custom BLDC controller that I made a few months ago!
We are still developing it so that exact version isn't online yet, but everything we make is open source :))
the string explanation is so good 😭😭😭😭
you should make a BLDC motor controller!!!!!!!!!!!
or explain how pure sine wave controllers work
@@LoganDark4357 did you know our bldc etch a sketch is a custom BLDC motor controller? Stay tuned, we will be releasing the design with our next video 🤠
I have a bunch of brushless motors from DJI s800. I've been thinking about turning them into servos. I'm just waiting for a more practical option to control them. They are outrunners. I'd like to design a housing for them with cooling considerations. That would allow it to run inside a gear box.
Go for it! Sounds fun to me 👀
"taking the steps to apply them to a project"
Pun intended?
Stepper? I hardly even know her!
This video covers the basics of steppers. But you don't really talk about why and when to use steppers vs closed loop. Generally speaking. Closed loop BLDCs will outperform steppers in every category. Speed, accuracy, acceleration, power, efficiency, size, etc. But if a stepper motor is "good enough" for your application, it's likely that using a stepper motor is cheaper and easier than a BLDC. Generally, if you don't need high speed, efficiency, high acceleration, super high positional accuracy, and small size, a stepper is the solution.
@@gizmoguyar good point, I could have summarized it better I think. For me I genuinely didn't have an intuition for what "high speed/ low speed", "high acceleration", or "small size" meant in quantitative terms so I just tested it out real quick. Then I thought it might be useful to show some maths for the upper bounds of motors in general.
Thanks for the feedback, summary, and for watching!
I understand using premeires to generate hype, but i get the notification for the premeire being announced, but not when the actual video is available.
Oh no 🤔🤔 maybe we will try out normal postings if a lot of people have this issue
Excellent
Maybe you should try using a different gear ratio since the steppers might have a higher torque, I don't know though
@@skyslycer no you're on the right track. To give them the best possible chance, you would want to find the motors most efficient speed and gear the system such that you're using that speed.
Ultimately we didn't go through the effort because we can see that the maximum power (assuming all was converted to perfect mechanical power output) was still not high enough to compete with our bldc motors.
To do better we should use larger stepper motors, but at that point it becomes unsightly hahaha
Isnt the current limit of the motor just a recomendation? Cool it enough and go higher amps
@@thomaskletzl6493 so this is a bit I couldn't fit in the scope of the video - but there are two limits to the "maximum current/ maximum torque"
1) for stepper motors of this style and materials, you will reach something called flux saturation. Reportedly close to 2.5x the rated current of these style motors, though I haven't tested it. This is essentially when the increased current will not generate stronger magnetic fields at a useful rate. You also risk demagnetizing the magnets at this range.
2) as you mentioned the thermals are an issue, and with stronger cooling you definitely can push motors a bit past their "steady state". However, Nema 17 motors are traditionally closed off and your only cooling option is through the case. Ideally you could force convection through the windings themselves.
@@EveryFlavorRobot do you have infos on how much microsteps is usefull? My drivers could go to 256x currently im on 16x i have no idea what is usefull and what not
@@thomaskletzl6493 ok so this totally depends on what system performance you need, but let me try to give advice:
Concern 1: noise - you will probably notice substantially quieter motors at 32 uSteps and probably won't notice much quieter past that.
Concern 2: processor speed - if you need a max speed and have to set it with step and direction pins, keep in mind it will limit you if running on a slow microcontroller. At 256th uSteps that's 50k+ steps to command PER ROTATION so at high speeds that could get spicy for small microcontrollers without hardware timers
Concern 3: accuracy, especially under load - stepper motors are designed to fall into "cogging" detents to ensure accuracy. Realistically as you increase uStepping you lose accuracy in exchange for resolution of electric field angle. What you will see is a lot of "magnetic backlash" as your motor will fail to move between uSteps.
Because of this, I've never seen above 16 or 32 uSteps used correctly. BUT there are cases when you could find them useful. There are also stepper motors that are wound specifically for high res uStepping - these will perform differently because they are wound and designed to reduce cogging, which will reduce their powered off torque as a trade-off.
Hope that helps! Good luck :)
guys, what happens when you stick and encoder on the back of a stepper motor and drive it with sinewaves based on the rotor position. pls show that
@@samm7716 using stepper motors for closed loop is interesting! We did a little testing and didn't find a way to fit it in the scope of this video but we could do more in the future.
Essentially however, this is a commutation improvement. Keep in mind that the max speed and torque will still follow Lorentz and Faraday's equations. Commutation can just help get closer to that!
When we tested advanced commutation on steppers, like FOC. We discovered a few things:
1) you need extremely high precision encoders because the motors have effectively 100 pole pairs. This means that for each of those ~3.6° segments, you need enough data points to calculate the best field angle to drive. Only during those points calculated will you get improved performance.
2) you need extremely fast clock cycle on the computer driving the controller. This is because of how many field updates you need to send, unless you have a hardware generated sine wave. Our max speed was limited by our calculations which was disappointing and didn't do it justice.
3) the gains in efficiency aren't nearly as cool as in a low pole pairs motor, especially when considering micro stepping. This is because micro stepping is already approximating a sine wave quite well
4) most unfortunately, FOC commutation like SVM can sometimes make more use of the voltage range for a motor but not for stepper motors. This is because the phases are 90° out of phase and thus are already maximally using the voltage range.
Tldr; we tried and it was disappointing and gave up, but may try again in the future!?!?
please do, I really liked the style and content of this video, and it felt like the topic of closed loop servos explained in this style would be a great video to watch, atleast for someone like, no one talks about, how bldc and steppers are kinda similar in this regard
Don't use gear reduction with stepper motors.
Ideally you would gear any motor down or up such that it's operating in its most efficient speed and torque. We didn't want to change the etch a sketch robot so we kept it at the reduction that was available to us 😅
22 min of proving the haters wrong B)
Williams Krater Charlotte Stevenson Benstein
Nice 👍👍
@@disastermaster7898 👍
Williams Maria Gonzalez Paul Walker Jennifer
Yes dude and you're so real for that
your bargain bin amazon steppers ain't the best, LDO, Leadshine, Moons all make some pretty good steppers, the key thing you wanna look at is torque curves, a simple way to get usable speeds for your motor, I can recommend LDO 2804s and 2504s, lots of high end DIY 3d printers use them. (annex k3 for example)
That said BLDC servos will be faster often times.
Very true, some day I will do a comparison of high end stepper motors because I am curious about them! I bet with thinner laminations and stronger magnets and smaller air gaps you can make some serious improvements!
However that said, I WAS comparing them against bldc motors that I got from AliExpress for 3.99usd - so roughly the same price point as these (which I stole from an ender3)
everything's an DC motor if you don't count the phases like a nerd
(niche crossover reference)
@@xymaryai8283 there's tons of UFOs flying around unless you're one of those nerds who knows bird names
Super nit-picky but please please oh please set your voiceover audio to mono 😭 It sounds like you're dancing around inside my head lol
Especially at the beginning
Sorry about that, maybe we should do a video on understanding sound design because I do not get it 😭