Is VESC the right board for me ?

General topics and discussions about the VESC and its development.
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fourchette
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Joined: 22 Jul 2016, 20:15
Location: France
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Is VESC the right board for me ?

Postby fourchette » 22 Jul 2016, 21:48

Hello

I am working on a small scale industrial prototype.
Until now I have mostly used steppers because I needed precise positionning.
Now with this project, I want to make a machine with two internal rotary mechanisms. I have not even finished a non-motorized version of this concept and I do not even know if it will work at all.
It is likely I will need torque, yet not that much. And I do not need excessive speed. Think of a washing machine with about 6 to 8kg of laundry that merely needs to roll, yet will likely start/stop pretty often, and I would like to have a decent acceleration. I will not use batteries. It would be nice/convenient to use compact motors making little noise.

I can reuse a couple of old brushed "big" dc motors and corresponding gearbox (typically from old unused conveyors with schneiders motor controller). But I would like to use that opportunity to use brushless motors in my designs for once. They are bound to be useful, even if it's not for that project anyway.

I have the feeling using some low cost very small brushless motors (typically for drones in the 500€ price range) will be likely too weak to work for this. But what is on an electric skateboard or an electric bike should work for me.

I like open hardware and would love to see more of such projects flourishing. So well, I stumbled upon VESC and it feels like some board I want to support and try out.

Sorry if the question feels dumb, please bear in mind I have never used brushless motors in the past. Given my context, should I give VESC a try?
Assuming yes, what kind of motors should i buy to get started ? (I was thinking of buying a one for a skate and one for a bike, and reuse some pulleys and belts I already have instead of a gearbox)

pf26
Posts: 310
Joined: 28 Mar 2016, 14:37
Location: FR Valence
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Re: Is VESC the right board for me ?

Postby pf26 » 23 Jul 2016, 12:01

Hobbyking SK6374 148Kv is a good start. Around 6Nm for short times (at 100Amps).
You probably don't need that much power, but than you will need to change the shunts to higher values to properly control lower currents with the VESC.
Here goes an example using 4114-320KV Turnigy (Near 1Nm at 30Amps) - to control the pitch angle of the unfinished wing in the background.

With (much) higher budget, you can have a look at Maxxon brushless motors, for instance EC 90.
Using VESC in special positioning mecanism will require some electronic/programming knowledge to send positioning/speed information to the VESC (preferably via CAN bus), but is really elegant/efficient solution compared with dc motors..

fourchette
Posts: 2
Joined: 22 Jul 2016, 20:15
Location: France
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Re: Is VESC the right board for me ?

Postby fourchette » 28 Jul 2016, 10:41

Sorry I'm far from home, connectivity is very limited and won't be able to look at video before next week or so.

I may indeed require precise positionning, sooner or later
I am not worried about programming nor building a mathematical model. However I am somehow worried about electronics.
I am assuming some kind of rotary encoder would be required but I have seen lots of options on my usual shops online. Magnetic encoders, optical encoders. On maxon they do sell gearboxes, motors and encoders, but the price feels prohibitive for now (by the way ec 90 is very flat, is it normal?)

I would rather start with a couple cheap models targetted for hobbyists to get more comfortable with the overall picture, and then once I am more confident with the overall stack really buy the right stuff

Let's say I get started with VESC for controller and say 3 different motors:
Sk3-6374-149k (big one for about 80usd, the one you suggested )
Sk3-4250-350kv (middle size about 40 usd)
Tunigy l3040A-480G (small and cheap just to compare with the others, about 20 usd)

What would be one or two good choice for rotary encoder ***that would be both compatible with the VESC and those motors*** ?

I'm kinda lost here :)

pf26
Posts: 310
Joined: 28 Mar 2016, 14:37
Location: FR Valence
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Re: Is VESC the right board for me ?

Postby pf26 » 28 Jul 2016, 16:02

Several people here use AMT10x or AMT11x from CUI inc. (available at mouser). I am a bit concerned about the long term reliability of these, but I never had problems so far. Otherwise, I use optical encoder like E6B2 from OMRON (you can get them on Aliexpress)
Any quadrature encoder with resolution > 8000 counts per turns, 5V input/outputs, and index output, should do.

Tallakt
Posts: 1
Joined: 24 Mar 2018, 09:12
Location: Norway
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Re: Is VESC the right board for me ?

Postby Tallakt » 24 Mar 2018, 09:15

You might be better off with a standard industrial VFD (variable frequency drive). You get these from eg. Siemens and Schneider. Price is from $250 upwards...


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