DIY BLDC / DC Motor Servo Drive - ARM MCU (STM32F103C8T6)

[KOC62]

Al_The_Man, I don't get the 90deg angle stuff and thought the signal was either on or off 1000 times per revolution....

That is correct. But your encoder has two channels, A and B. If each cycle is 360 degrees (i.e 1 half ON and 1 half OFF) and you displace the B channel by 90 degrees(quadrature) then counting each edge of both channels will give 4 possible transition per cycle. Well, ... that is how I see it.

[Al_The_Man]

Al_The_Man, I don't get the 90deg angle stuff and thought the signal was either on or off 1000 times per revolution sot basically you're saying I have a 4000cpr encoder and this makes sense as it works out with the steps in Mach3.

.

Ok The basic quadrature encoder has two square waves, displaced by 90° (quadrature) , originally the simple usage was to use one rising edge as count (basic count/rev) the other pulse the direction, soon it was observed the resolution could be increased by either using two of the rising edges of the pulses (x2), or every rising and falling edge (x4).
So this became the most common way of increasing the basic count resolution if desired.
What you have is a basic 1000 count encoder that the either the drive or the system takes advantage of the x4 capability, BTW Mach CNC does not count the pulses as the control is not closed back to the Trajectory planner as it is in commercial CNC or motion card etc, but is the responsibility of the drive to use the x4 to increase the resolution and track position.
Al.

[jimmkaz]

Brad43,

After being a member of the forum for less than a day how and why have you come to the conclusion that this thread needs a project manager?
There are already several moderators here including one that stated if the goal of the group or individual was not Open Source to start a new thread.
Now you decide to focus the same disdain for the rules that "Dwalsh62" and "Websrvr" exhibit.
Repeatedly you have told me I am making a mistake and make irrational, disparaging, innuendos why I am the one derailing "Dwalsh62" and "Websrvr" efforts to complete our Open Source Project. When in fact "Dwalsh62" and "Websrvr" have stated on numerous occasions that they do not have the ability to develop or share Open Source firmware for this project.

Your opinions are not well thought out to say the least.

[websrvr]

websrvr, I was kinda hoping to use the touch screen I already have but if you give me a link I'll buy the one you recommend, if it's OK with you, I'd prefer to have our discussions in private messages, I'm not interested in being a part of this debauchery.

There's no need to be private about the reflow oven related stuff and if you don't engage anyone they wont engage you and you can ignore any one you don't wish to have dealings with.

Also, others are answering you with technical details/information regarding some of your questions that wouldn't hurt for you to know about, the information might come in handy later so don't discount it just because you don't understand it now..

KOC62's description is a less technical version that may be easier for you to understand but Al_The_Man's explanation is more accurately described in layman's terms.

Give you a link for a TFT, you go to ebay and you pick the person you want to buy from is your hardest decision to make, I only told you what TFT the app will operate with but I can't tell you specifically what TFT to buy or who to buy it from, I didn't buy mine from ebay and the guy who had them doesn't have any extras anymore so this is what you do:

1. go to ebay.com
2. in search field put "3.95 TFT Uno"
3. ignore the ones priced at $129.xx
4. pick one of the cheap price sellers
5. click "buy-it-now"
6. pay for it
7. contact me when it arrives

KOC62,tonight over drinks I will be discussing the alternate compliment pin issues with an STM32 expert who came highly recommended in the embedded development field to get a better understanding of why it is better, I'll let you know what she says about it tomorrow.

Made more progress this afternoon, after some testing, I can tell you the MI is required on PWM-A and definitely makes one of the current sense lines (which one is dependent on rotational direction) always zero and I'm finding that it's easier to use the 20:1 current sense amplifier (AN271) to calculate and track the actual current using simple whole number math.

As I delve further into the STM32 world more questions arise and I think the answers need to come from someone with experience or knowledgeable in PWM programming.

I've been looking over some of the related servo projects, later this week I'll try incorporating some index code from one of the projects to see if there is really any benefit to using the encoder index in this application since commutation is taken from a table it might serve no purpose other than tracking/reporting true shaft positioning and possibly table synchronization but I could be wrong.

The STMBL code calculates commutation on-the-fly, the code is a little bloated and I'm not sure if it would provide any benefit to do it this way over the lookup table except to save memory but wouldn't an "on-the-fly" solution be slower than a lookup and if so, why does the STMBL code do it this way as the used memory resources are less than 6K according to the allocated variables when more is available.

I've now looked at several servo related projects that seem to do everything differently to achieve the same results and am wondering if all of the functions and methods currently used in the Mihai code are appropriate or correct because there are so many different ways to achieve the same results, shouldn't emphasis be placed on execution speed for optimal performance?

Something else that crossed my mind, how would ST be able to determine from looking at the Mihai code that it's a student related project as the code is not much different than what is generated using the CubeMX software and all of their motor related tutorials rely on the CubeMX software to generate the basic PWM code.

With the information provided by ST engineers it would have been nice if they provided an outline of the firmware requirements for the schematic they created that would give optimal performance for it making everyone's life easier but then again, that would make it too easy if they did all the work.

Something that was recently pointed out to me is the disclaimer embedded in the schematic, does this imply they don't trust the work they provided or is it they can't guarantee the results because they're not providing the firmware and what kind of money did they want to provide the firmware for it as there is no mention of any amount except expensive which is not very descriptive?

[Brad43]

websrvr, bought this one, 14 to 21 days for delivery from china **3 95" TFT LCD Shield Touch Panel Module TF Micro SD for Arduino Uno R3 | eBay


jimmkaz, what rules am I ignoring or complaining about?

Yes I am new here and only because I need to know what you're intention was for this project when you got rid of the only person who seemed to be working on it.

You are the one acting like the leader, publicly announcing who you don't want involved in the project claiming everyone else has the same sentiments but I don't see anyone else saying they didn't want his help but you.

You have*admitted*you have no plan, you just wanted him gone and now the rest of us are made to suffer because you didn't consider the project or those interested in it when you made and attempted to enforce your decision.

Now if you claim you didn't kick him out, you can keep that lie to yourself, you did everything in your power to make it difficult for him to participate, you publicly*announced*that you and everyone else wanted him gone, no one can work under those conditions and to deny this now would make you a liar.

Wow, you're really good at twisting the truth, only you are claiming that websrvr doesn't have the capabilities to develop or share open source software, what I read tells me that he's*unfamiliar*with it but learning about it and from his last post it's looking like he's making some progress.

Instead of helping him you decided it was best to get rid of him and the real reason is unclear*because*I'm seeing a lot of conflicting and twisting of statements from you, this is why your decision to get rid of him was made prematurely and anyone reading your posts can figure this out easily.

It also looks like pommen isn't joining you because he's made no more posts since his last one to websrvr so are you also going to claim this is due to his lack of capability to develop and share open source software?

[websrvr]

websrvr, bought this one, 14 to 21 days for delivery from china **3 95" TFT LCD Shield Touch Panel Module TF Micro SD for Arduino Uno R3 | eBay


jimmkaz, what rules am I ignoring or complaining about?

I advised you not to engage anyone you don't want to talk to and the next thing I see is you arguing with someone you told me you didn't want to talk with so now he's sucked you into his world of drama.

He's been here since 2009 and has only made 14 post and guess where those posts are.

I've been here since 2012, have 43 posts (not counting this one) a few posts in some other threads and around twenty posts in this one.

I don't need you defending me or pommen, I know I never said I couldn't do it and others can read this, I said I had no STM32 experience and needed to learn about it first, he's perverted everything I have said to make himself look better and powerful so my advice is ignore him and go about your own business.

The next bit of nonsense I expect from him is a claim that pommen and I are the same person and I wouldn't put it past him considering his track record.

If you continue dealing with him you're only going to find yourself in some kind of trouble so I am reiterating to you again, just ignore him and you wont have any problems.

[jimmkaz]

This might peek someone's interest. There is a Open Source d.c.servo project on hackaday complete with firmware and a inexpensive encoder that may be a good fit for a Taig sized machine.

https://hackaday.io/project/9433-brushed-dc-servo-drive

[jimmkaz]

Projected cost for a complete servo drive with encoder $40.00

[websrvr]

KOC62, have you ever looked forward to meeting and discussing something of a shared interest with someone and then after meeting with them wished you had sent your nemesis, tonight was one of those nights for me.

Until tonight I thought I only knew one person who left me with the feeling that I had been massaged with a cheese grate but to my surprise, the lady I just spent an hour with makes him seem like an angel in comparison, why are these people so harsh in nature?

Why are these types of people not people friendly?

Also, why do these types of people seem to have sleep disorders or is this just coincidental in these two individuals?

While it was hard to stomach being treated like an infant still in diapers from a woman who could obviously bench-press a harley and I thought I saw the shadow of a mustache growing under her nose or it could just have been the dull lighting.

I swallowed my pride to listen to the explanation along with a visual presentation on a nice four channel 10in digital oscilloscope which showed that the issue cause by the delay in the compliment channel actually affects the time when power is applied to the motor and a magnetic field is generated and it's not just about the delay of the compliments channel alone, it seems that the on time of a normal or high channel must occur with an on time of a low or compliment channel and both remain on for a specified amount of time which is static based on the PWM frequency and it's duty cycle to generate the magnetic field required to make the motor turn, as you increase the delay time that the low or compliments channel turns on it means that both are on simultaneously for a lesser amount of time and as the on time of the compliment channel happens later, the normal or high channel turns off after being on it's specified time the amount of time in which both are not on is increased and when this simultaneous on time is reduced to around 75%, torque is greatly affected, if this is reduced below 60% stuttering occurs and below 20% there is insufficient power in the magnetic field to make the motor turn, hopefully I have explained it correctly.

Being able to see the magnetic field on four channels from a box and these six large coils placed around the stator was something I'd never seen before, I didn't ask questions about the equipment because I didn't want to stick around any longer than was absolutely necessary but noticed a collection of toys like a 144-channel digital signal analyzer, 64-channel digital capture buffer with 30 second playback, an Atmel FPGA/PLC programmer with six sockets on it and all kinds of other test equipment I'd never seen before, several bottles of "Liquid PCB" something I also never saw before, some kind of mini tesla coil looking type of device for an unknown purpose, just tons of toys everywhere, no real sign that a person lived in the place, more like a hidden secret electronics laboratory.

So the explanation with visual presentation made sense but I sure wish it would have been easier to get than the way it was given by the person who gave it, there was definitely no desire to stick around for more conversation and I was glad to quickly exit.

[ger21]

A little advice.

If you don't like what someone says, ignore it.
Every one of you is pushing this thread closer and closer to being permanently closed.

[KOC62]

... why are these people so harsh in nature?

Why are these types of people not people friendly?
.

Fundamentally, a serious lack of genuine love towards all people.... but that is an off topic discussion and can be fleshed out in the "lounge".

OK, the answer does then lie in "field saturation". To get the full torque we need full current. The commutation process thus needs to be accurate with precise timing to get those results.
Thanks for taking the your time to share this understanding with us. Hands-on experience can reinforce these findings. Awww, I only have a dual channel 'scope.

[KOC62]

This might peek someone's interest. There is a Open Source d.c.servo project on hackaday complete with firmware and a inexpensive encoder that may be a good fit for a Taig sized machine....

That may be more up my alley. It is a brushed, not brushless, DC motor project. I'd like a 200V version.

Edit:
It looks like a project by our member James Newton as a team player.

[KOC62]

KOC62

Take a look at this if you have more interest in the inexpensive encoder solution:...

Thanks. There are so many places one can find to learn stuff!

I've been using a paper printed strip with 18 black-white stripes wrapped around a drill chuck. Then used a reflective opt-sensor. The demo worked surprisingly well for what I was learning. I didn't have a second opt-sensor so I didn't do a quadrature encoder. I'm just learning with the parts I have to establish the concepts. Someday I may buy an encoder and further my leisure studies.
It's so nice to tinker with no pressure to produce anything ...

[Brad43]

massmind.org finally responded back to me, unfortunately the kit they are selling is not a full complete kit, you are still required to provide a breakout board and a controller for each axis that will drive an h-bridge board for brushed motors and read the encoder board, they do give recommendations for the axis controllers, one being an Uno and they provide the flash file for it, instructions on how to glue on the magnets and distance the encoder IC is from the magnet, 90ppr/360ppr (single/quad) encoder, dual h-bridge is 4A/7A (cont/peak), they also said that any h-bridge with a single PWM input and a DIR input could be used so I could get one or make one for a BLDC and it would work the same and they give all kinds of software, information and links, while the kit is fairly complete, it's not a turnkey solution so I wouldn't call it a cheap $40.00 solution when there is additional costs but I will agree it is cheap even adding in the cost of the Uno's it's still less than $50.00 for each axis and all you need is suitable motors and power supplies.

The low step per revolution means accuracy is good enough for a low pitch ballscrew or leadscrew but high precision equipment was never it's intended target.

I haven't made a decision to buy yet, they said it will be at least 3 weeks before kits will be available to ship so I have time to decide if it's something worth playing with. or wait for this project to have software.

[websrvr]

massmind.org finally responded back to me, unfortunately the kit they are selling is not a full complete kit, you are still required to provide a breakout board and a controller for each axis that will drive an h-bridge board for brushed motors and read the encoder board, they do give recommendations for the axis controllers, one being an Uno and they provide the flash file for it, instructions on how to glue on the magnets and distance the encoder IC is from the magnet, 90ppr/360ppr (single/quad) encoder, dual h-bridge is 4A/7A (cont/peak), they also said that any h-bridge with a single PWM input and a DIR input could be used so I could get one or make one for a BLDC and it would work the same and they give all kinds of software, information and links, while the kit is fairly complete, it's not a turnkey solution so I wouldn't call it a cheap $40.00 solution when there is additional costs but I will agree it is cheap even adding in the cost of the Uno's it's still less than $50.00 for each axis and all you need is suitable motors and power supplies.

The low step per revolution means accuracy is good enough for a low pitch ballscrew or leadscrew but high precision equipment was never it's intended target.

I haven't made a decision to buy yet, they said it will be at least 3 weeks before kits will be available to ship so I have time to decide if it's something worth playing with. or wait for this project to have software.

I'd stop relying on this project until it has someone developing the firmware, there are other solutions available if you want something now or you can roll up your sleeves and tackle Mihai's code as part of the project or write your own.

For a mill like the Shirline or Taig the "partial comlete kit" would be useful as an upgrade path if you had suitable brushed motors, since it has no IPM or current management don't expect a 4A motor to work with the driver without modifications, it's peak current will be well over 20A but the good news is, the fine pitch leadscrews in these small machines would still provide excellent precision at 360 steps per rev, if you're using a 5mm pitch ballscrew then it's questionable but probably more than acceptable in a hobby community.

I've made more progress tonight and before anyone get's the idea to ask for my code, sorry, it's for personal use only, you'll have to wait for this project to figure out what it's doing and then go with whatever it has to offer.

All I have left is the DC-Link and Back-EMF coding to do and I'm done.

[jfong]

I will rather wait for 40bucks James Newton electronics to control brushed DC its dirt cheap...

I built his version of the Linistepper a long long time ago. Works great. I'm going to breadboard the servo project this weekend.

[jfong]

Just ordered one of your encoders. Have a ton of microchip hardware/programmers but don't have a 18f14. Looking over the source/datasheet to see if I can target one of my other 18f devel boards. Nice work. I'll take this offline if I have any questions but everything looks fairly straightforward.

[Brad43]

This is written over the course of several hours as I contemplate everything involved and related to the project instead of making a million small posts and may not be really fluid as I jump around and also I realize that some of what I will say will cause people to spout off on objections to parts and this is beyond my control so if you want to complain about something I've said, please don't bother, you've interpreted something that is offered general in nature to be personal about you and it's not.



James Newton, I've never used any PIC based products and the e-mail to Terry Bradley and I was pretty explanatory that driving the motor stage can be done with almost anything such as a Atemga328 to PIC but more technical than either one of us could grasp and walked away only with the understanding that there are many ways to make your stuff work and while I can't comment on any personal experiences with PIC based stuff I am willing to try it out as part of your complete system package when it's finally available.

Offering a complete system is worth checking out if it's cost effective, $120.00 per axis plus whatever your BOB cost is still within a hobbyists budget but pretty much at it's limit before the cost of a stepper system takes over so I can accept this, could you private message me when your PIC boards and other stuff are all finished and ready to ship, I'd be more than happy to buy everything needed for a complete 3-axis setup and try it out on my Taig as a full system guinea pig tester for small machine (Shirline/Taig) applications, I'm just looking for a complete solution with as little work on my part as possible, assembling boards is not one of my better skills and it takes weeks to get the help I need to assemble them so assembled boards is better for me and the cables and plugs in your setup means little work in correct wiring is required to connect each section together so my problem would mainly be on setting up Mach3 correctly for your system which I could manage without assistance.

Also, are you considering another encoder kit with 1000cpr or 2500cpr encoders, I like the idea of higher resolution for greater precision but I do understand that the 360cpr is suitable for my current setup, I'm just thinking about in the future using them on something that has a 5mm or 10mm pitch ballscrew or a rack and pinion system which has about 3in per turn (7TPI rack and 22T pinion).

Since my transition from steppers to servos seems to show better speed and performance even though there are issues with the Mihai drivers at this time, the thought of going back to steppers puts a bad taste in my mouth, finding a good working solution in a hobby budget seems to be more of a problem, all kinds of projects are out there, some too expensive for the hobby user but nothing that is really complete that meets a hobby budget or so complicated that you need a degree to install and operate it.

I think Mihai's project has great potential and I think it's really close to being all it can be if some of the issues are fixed but no one seems to be working on it as an open source project and a lot of effort is being spent preventing or squashing it's open source development and this is unfortunate.

Losing people because they are banned for any reason (not complaining about it) or emphatically demanding they leave for any reason because they are making efforts and progress is mind-boggling to say the least and almost makes it appear that no one really wants it to be fixed and/or completed.

There is way too much bickering and this can be seen by reading the thread, I'm now making a conscious effort to avoid conflict and since jimmkaz has gotten rid of websrvr he's now (jimmkaz) appearing to contribute some useful information making it harder to ignore him but he doesn't appear to be doing anything to help this specific open source project from what I can see.

Also, I don't think websrvr's comment about not relying on this project to be related to James Newton's stuff, I think it was about this project in general but I could be wrong.


This is a large playground, getting along makes it more enjoyable but people are generally diverse in their backgrounds and upbringings and clashes are bound to happen but solid leadership usually tends to control these outburst not create or participate in them.


jfong, I wouldn't call what websrvr is doing a new project, it's based on this project, started with this project, code and the updated schematic in one of the post which demands changes to Mihai's original code which from what I can read and understand offers a better implementation and to now ask for his code after forcing him out I doubt he'd be willing and if you were in his shoes would you want to give your code to the group of people who kicked you out by making it impossible to contribute?


Let's talk about the PCB/layout for a moment, I can load files into eagle to view them like many others and this is about the limits of my capabilities but we have seen that other people here are capable of creating board layouts, why hasn't one of them taken the initiative to create a layout of the updated schematic and why are people reluctant to make this effort?

I don't know how to do anything in eagle but view them, most files it says I can't change in the free version and I wouldn't know what to change so it doesn't really matter that I can't but is it possible for someone who can to import the pictures of the board and convert them to a layout file because I see you can import images in eagle?

If you know how to work in eagle, how hard would it be to make the changes to the Mihai files so you don't have to start from scratch or is this more work and easier to start fresh?

If you have to start fresh, how difficult would it be to take the pictures of the board and use them as references to make a new board file?

And finally, how difficlut would it be to solicit for someone with eagle experience to do this work or is the general consensus that the project isn't worth the effort?

I think getting someone to make the board file would be a positive and forward moving effort for this project since everyone is complaining that no board layout is available for the updated schematic.


If you or anyone felt that what jimmkaz was doing wasn't beneficial to this project then you or they should have made some kind of statement or objection rather than say nothing and go along with or allow him to make these decisions but to disagree without saying anything is basically agreeing with what he was doing giving you no recourse or ability to now demand websrvr hand over his code, just my opinion.

Not one person asked him to stay which pretty much implies that everyone was in agreement with the decision and action of jimmkaz and if he's now finished or almost finished the code asking for it would be considered arrogant and insulting, you want the code he created but do not want him as an active participant of the project, not a good way for an open source project to treat developers, programmers, creators of works or anyone for that matter, again, just my opinion.

Another observation, why do programmers all have some kind of bad attitude towards each other, it's not supposed to be a competition, it's supposed to be a collaboration or so I thought.

I could see websrvr was driven to work on the project by the effort he was making, he was learning the information required and making an effort to change the code as required without anyone helping him and if you are a sensible person you would agree with this, not saying you or anyone else is not sensible, just an observation.

It looked like Pommen was willing to assist but I have since concluded he changed his mind after the last fiasco and while I don't like it, I don't blame him for not wanting to join the circus.

I would have liked to have helped myself but I don't have the programming expertise that everyone else here does, I feel like I'm in programming pre-school and I think I would be more in the way and less of a help and slow down development with silly question about all the stuff that I don't understand which is pretty much everything.

Four hours off and on, done thinking about this stuff, had/said enough.

[websrvr]

Brad43, I told you I don't need you defending me.

Now, I've been known to be pretty long winded but that posting beats me hands down.

Newton's been around for some time, well respected and has a good clue so I wouldn't question what he says, his projects are getting better over time, I've never seen him leave a project in a bad state and his stuff is usually appropriate for it's intended target audience, if he says it good for a small machine then I would accept and agree with it based on his history and experience in the field, if he says he'll have a full kit soon then wait it out, it sounds like it would be perfect for your machine and it sounds like he targeting this small platform as his entry point and it's a good place to start as he can only go up from there and the experience a great learning curve for him.

The other nonsense about me and working on the project, they didn't want my help, they wanted me gone, I'm gone and that's it, I'm no longer a part of this public open source project and have nothing to contribute to the project itself other than the progress I've made since my outcasting, I'm not obligated to share anything with anyone and if I do, it's a courtesy not an obligation, anyone involved in it foolish enough to ask for it has more issues than medication can fix and demanding my code would require immediate hospitalization for delusional psychosis.

My final update, my code is done, I had it critiqued and was advised to rewrite some routines to prevent some potential conflicts and an endless self sustaining loop in the PID under a certain condition so I'll do my polishing over the next week or two and make sure I've removed all the bugs before putting it to bed.

I still wish everyone here good luck with this project and hope they figure out what they're doing with it, I know from my own results, the effort is definitely worth it.


Oh, I do have something I can contribute to the project itself if someone wants to develop the firmware for the project, the blue boards I posted the pictures of, I no longer need them for development purposes since I'm done developing my firmware, I've increased my order for populated boards so if anyone is interested in the boards they are available. I also have two paste stencils I can toss in at no charge since I no longer need to assemble any boards for development and if someone buys the whole or half lot they can have them (1 stencil per 5 boards purchased), if you only buy one board the best I can do is give you the gerber file for the stencil, and, I also have some of the regulators, MAX3097's. IRS2101's and USB connectors I can also toss in to the lot since I wont be needing them any more either.

[jimmkaz]

websrvr,

My pal, JoeyB told me you would really enjoy the Massmind Open Source Servo Project. I disagreed with him however he was spot on.