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Old Jan 01, 2014, 10:27 AM
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United States, IN, Indianapolis
Joined Dec 2011
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An introduction!

Greetings to everyone! The names Jon! I have been out of the RC hobby for about 13 years and am at a point in my life where I have decided to jump back in. Planes were my thing 13 years ago so I am going down the same road again.
I am a 1 year Electrical Engineering student, almost 2nd year. I will be designing and building my own electronics. I have access to an amazing electronics lab so if anyone needs anything done that takes a profession R&D lab let me know!
My first question here is what are most Brushless ESC's using as far as MCU is concerned. From the info I have gathered so far the Atmel8 and 16 MCU's seem to be really popular. Has anyone ever used ARM MCU's. ST's line of ARM MCU's are really impressive. And are all BLDC motors used in RC flight Sensorless? I have not seen and of them with hall effect sensors on them yet, so just wondering.
Second, can you guys offer any good recommended reading websites that detail Brushless ESC design? Thanks for the responses in advance!
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Old Jan 01, 2014, 10:52 AM
AndyKunz's Avatar
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Joined Sep 2001
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Originally Posted by jtroutt19 View Post
My first question here is what are most Brushless ESC's using as far as MCU is concerned. From the info I have gathered so far the Atmel8 and 16 MCU's seem to be really popular.
Yes, that's true. Atmel is very inexpensive in China, so that's the most common one it seems.

Quote:
Has anyone ever used ARM MCU's. ST's line of ARM MCU's are really impressive.
Yes, and the ST parts are very good because they provide peripherals precisely for power supplies and motor controls. Microchip also has a variety of very suitable parts primarily in the dsPIC, PIC24, PIC18, and PIC32 lines. (PIC32 is MIPS core instead of ARM). TI has great products for this as well. Both TI and Microchip have excellent BLDC app notes.

Quote:
And are all BLDC motors used in RC flight Sensorless? I have not seen and of them with hall effect sensors on them yet, so just wondering.
In practice, yes, but I still have sensored motors for planes from the 1990's. Sensorless allows adaptive timing but gives up good low-RPM operation. If there's a particular reason you want to use a sensored motor, look at the car products.

Quote:
Second, can you guys offer any good recommended reading websites that detail Brushless ESC design? Thanks for the responses in advance!
TI and Microchip, as noted above. Although I'm a Microchip Design Partner, I actually prefer the explanations in the TI documents.

You're welcome.

Andy
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Old Jan 01, 2014, 11:38 AM
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United States, IN, Indianapolis
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Hey Andy, thanks for the info. One thing I have not learned yet in school is MCU programming and the different variants of the chips on the market such as MIPS, ARM, AVR, and so forth. If my thinking is correct it has to do with how instructions are handled within the chip.
Are there pro's and con's on which to use and which to not? Do you have any resources on MCU programming that would allow me to get my feet wet? Thanks
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Old Jan 01, 2014, 12:40 PM
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Do you have any programming experience? What language(s)?

Andy
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Old Jan 01, 2014, 02:31 PM
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You could say that I really dont have any. lol. I have played around with HTML, JAVA, and python. But not enough to be able to do anything. The problem with trying to self teach is that I end up not understanding what is going on. I will be taking a class in C/C++ programming in about 6 months. I am wanting to go into the class with some knowledge under my belt.
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Old Jan 01, 2014, 03:41 PM
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http://www.microchip.com/wwwproducts...cName=en559165 -dsPIC33FJ06GS001
Do you think this is over kill for an ESC application?
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Old Jan 01, 2014, 06:16 PM
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I'm not so good with the total greenhorn. I'd be more useful to you after you've done some C work.

There are some good books out there, and lots of the chip companies have boards like the Arduinos to give engineers a head-start. Actually, Arduino might be a great place to start. A sensorless ESC would be a bit of a challenge for a first project. Perhaps starting with a brushed ESC would be a better place.

One of my friends from way-back did some books which might help you. Google for myke predko books. They're a bit dated, but the projects still work and Microchip still has the same chips and (MUCH improved) tools available to work with. They have starter kits which might fit your budget, too.

Andy
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Old Jan 01, 2014, 08:35 PM
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That is funny that you mentioned C. I have alot of resources available to me through my school and its online virtual library. That being said I have started a introduction course in C this evening. Working with Code::blocks and the compiler that comes with it.
I will be receiving an Arduino from school here soon, they provide them in our embedded electronics course. As far as challenges go, the harder they are the more I enjoy them. I am going to order some PIC's from Microchip also going to get a few Atmel's as well. This ought to be a fun endeavor that will allow the wife to yell at me! lol. Thanks for the help Andy!
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Old Jan 02, 2014, 08:10 AM
Dave the Rave
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... This ought to be a fun endeavor that will allow the wife to yell at me! lol. .....
That shouldn't be too hard to figure out how to do. At least, it never has been for me.....
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Old Jan 02, 2014, 06:38 PM
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United States, ID
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Greetings to everyone! The names Jon!
We already have a Jon... so we don't need you.


Just kidding! Welcome to the club!

I like using PICs since they're pretty rugged and simple. Microchip now has a great compiler and IDE (MPLAB X).

I started with gear from piccircuit.com. I can reccomend...
iCP07 - iBoard Tiny
iCP02 - USB PIC Programmer (3.3V/5.0V)

That should get you started programming 3.3v and 5v, 8-pin PICs.

If you're interested in ignition systems, you can check out my open source ignition project in this forum. My code may be a little complex, as it jumps right into interrupt driven stuff, but it is very well commented so you should be able to figure it out.

The download links are somewhat buried and scattered in the thread. If you can't find them let me know and I'll dig them up for you. I think Ray has collected most of the files since my site went down.


Here is an interesting thread on brushless ESC ideas...
http://www.rcgroups.com/forums/showthread.php?t=2042526
We need an expert to figure out how to implement a FOC ESC, I don't think it's been done before, and sounds like it's right up your alley.

I'd suggest learning C and sticking with it. Ignore all the BS about BASIC and Audrino Wiring Language. People that go down that path end up chained to one platform struggling to figure out oddball "training wheels" languages.

C is as easy and straightforward as it gets, and almost every popular modern language is directly based off of it. There is nothing easier to learn or more powerful.


-Jake
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Old Jan 03, 2014, 04:17 AM
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Arduino is C/C++.
The most native C or C++ programs need only main() renamed in setup(). Et voila the Arduino IDE compiled this then without uncomplaining.
On the other way I can use the Atmel Program Studio and compile an Arduino Sketch. It's only a little bit knowhow.
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Old Jan 03, 2014, 09:45 AM
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United States, IN, Indianapolis
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Originally Posted by jakestew View Post
We need an expert to figure out how to implement a FOC ESC, I don't think it's been done before, and sounds like it's right up your alley.
-Jake
What does FOC stand for..haha... One thing ive learned that is indispensable is that EE's and ECT's love abbreviations and acronyms..lol

Thanks though for the info. And ill do my best for you guys. If you put your mind to anything it can be done. I mean hell I've made it through my first year of EE school and maintained a 3.83 GPA
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Old Jan 03, 2014, 01:45 PM
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I'm happy to help with the programming if you want to try implementing a FOC ESC. Microchip already has code and appnotes for it. I just have no good understanding of the electrical theory.
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Old Jan 03, 2014, 07:14 PM
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First thing first I have to have a complete understand of how a ESC works and how to code the MCU's. Electrical theory is easy in my opinion alot of it is common sense but thats me.
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Old Feb 12, 2014, 03:00 AM
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Heya guys, I've been trying various appnotes from Microchip for the last 3 months and the only reliable one was AN1160. Unfortunately the max RPM is very very limited because of the ADC conversion trigger which is based upon the PWM pulses. To put it mildly, higher RPM, a lot more commutations ---> higher PWM frequency. I got up to around 8000 RPM which is well below the 21.000 RPM motor limit. I used a dsPIC30f3010 and fooled around with the source code from AN1160 and AN1083. If anyone used these appnotes and got a high RPM like the esc's based on ATMEL please share the source code
Anyway I'm building my own hardware , again, but this time with an Atmel CPU and see where it goes. Happy flying everyone!
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