3-axis closed loop motion control January 12, 2017 08:36AM |
Registered: 7 years ago Posts: 14 |
Re: 3-axis closed loop motion control January 12, 2017 11:51AM |
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Re: 3-axis closed loop motion control January 12, 2017 11:59AM |
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Re: 3-axis closed loop motion control January 12, 2017 12:01PM |
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Re: 3-axis closed loop motion control January 12, 2017 12:33PM |
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Re: 3-axis closed loop motion control January 12, 2017 01:20PM |
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Sensors I've found so far seem to run $10/piece
Re: 3-axis closed loop motion control January 12, 2017 02:15PM |
Registered: 7 years ago Posts: 14 |
Re: 3-axis closed loop motion control January 12, 2017 03:08PM |
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Re: 3-axis closed loop motion control January 12, 2017 03:23PM |
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Re: 3-axis closed loop motion control January 13, 2017 04:03AM |
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Re: 3-axis closed loop motion control January 13, 2017 04:59AM |
Registered: 12 years ago Posts: 1,236 |
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AleksClark
The benefits of closed-loop control should be pretty obvious:
- cheap DC motors instead of steppers, for a given torque
Re: 3-axis closed loop motion control January 13, 2017 09:49AM |
Registered: 8 years ago Posts: 916 |
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bobc
I bought some of these [www.ebay.com] to play with, but I'm not a hardware guy. If someone could build a driver board, writing the software should be straightforward. For proof of principle, I would build a 3 axis motor driver encoder interface.
Re: 3-axis closed loop motion control January 13, 2017 10:14AM |
Registered: 7 years ago Posts: 14 |
Yes, I do realize that the hardware is fairly trivial atm, and the bulk of the work is software, that's why I chose this particular avenue of contributionQuote
o_lampe
As long, as you don't find a software guru willing to write firmware for it, your project is just a dream.
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bobc
A Nema17 + driver costs around $15. So far no one has designed a DC motor + encoder + driver for less than $15.
Re: 3-axis closed loop motion control January 13, 2017 10:21AM |
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Re: 3-axis closed loop motion control January 13, 2017 10:22AM |
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Re: 3-axis closed loop motion control January 13, 2017 10:28AM |
Registered: 7 years ago Posts: 14 |
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JamesK
You probably need to add a gearbox to your prices, and I'm not sure if brushed DC motors are the right way to go. At least the drone market is reducing the prices of nice BLDC motors
Re: 3-axis closed loop motion control January 13, 2017 10:44AM |
Registered: 10 years ago Posts: 14,672 |
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JamesK
You probably need to add a gearbox to your prices, and I'm not sure if brushed DC motors are the right way to go. At least the drone market is reducing the prices of nice BLDC motors
Re: 3-axis closed loop motion control January 13, 2017 10:51AM |
Registered: 9 years ago Posts: 1,873 |
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dc42
BLDC motors come in two sorts: ones with commutation sensors, and ones without (so the controller has to use back EMF sensing). The ones without commutation sensors might not work in this application, because at low speeds there is probably insufficient back emf to detect. The ones with commutation sensors should be ideal if the price is right, because you won't need a separate encoder.
Re: 3-axis closed loop motion control January 13, 2017 12:22PM |
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Re: 3-axis closed loop motion control January 13, 2017 12:41PM |
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Re: 3-axis closed loop motion control January 13, 2017 12:47PM |
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Re: 3-axis closed loop motion control January 14, 2017 03:28AM |
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Re: 3-axis closed loop motion control January 14, 2017 03:42AM |
Registered: 10 years ago Posts: 14,672 |
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o_lampe
I was wondering, if we could use optical mouse sensors as encoders?
They work on almost any surface and have a pretty good resolution. I could imagine, they are cheap too.
Just put such a sensor on your linear rail and let the 2020 profile be your encoder strip.
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o_lampe
Regarding suitable dc motors, we could look into car industry. There are tons of 12V motors in a luxury car. (eg. electric driver seat adjustment )
Might be, we find a suitable, mass produced geared and encoder-fitted motor for cheap.
Re: 3-axis closed loop motion control January 14, 2017 03:58AM |
Registered: 8 years ago Posts: 5,232 |
Re: 3-axis closed loop motion control January 14, 2017 06:10AM |
Registered: 12 years ago Posts: 1,236 |
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o_lampe
I agree with David, brushes can wear out, but a DC motor is so much easier to control.
E. g. the L6234D chip is a 3phase H-bridge, able to control one BLDC motor or three DC motors. It would be a good starting point for a new generation of controllers.
Re: 3-axis closed loop motion control January 14, 2017 06:52AM |
Registered: 10 years ago Posts: 14,672 |
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bobc
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o_lampe
I agree with David, brushes can wear out, but a DC motor is so much easier to control.
E. g. the L6234D chip is a 3phase H-bridge, able to control one BLDC motor or three DC motors. It would be a good starting point for a new generation of controllers.
That's a triple half bridge, I think for bi-directional control you need a full bridge. There seem to be a lot of driver chips for small motors though, as noted cars are now full of them!
Re: 3-axis closed loop motion control January 14, 2017 07:16AM |
Registered: 12 years ago Posts: 1,236 |
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dc42
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bobc
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o_lampe
I agree with David, brushes can wear out, but a DC motor is so much easier to control.
E. g. the L6234D chip is a 3phase H-bridge, able to control one BLDC motor or three DC motors. It would be a good starting point for a new generation of controllers.
That's a triple half bridge, I think for bi-directional control you need a full bridge. There seem to be a lot of driver chips for small motors though, as noted cars are now full of them!
A triple half bridge is sufficient. See [www.digikey.co.uk].
Re: 3-axis closed loop motion control January 14, 2017 08:08AM |
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Re: 3-axis closed loop motion control January 14, 2017 09:09AM |
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Re: 3-axis closed loop motion control January 14, 2017 12:42PM |
Registered: 8 years ago Posts: 5,232 |