Author Topic: microcontroller to control 4 brushless simultanously  (Read 2178 times)

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Offline mba7Topic starter

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microcontroller to control 4 brushless simultanously
« on: November 05, 2008, 04:00:12 AM »
hi everybody,

does anyone know if there is a micocontroller that can control 4 brushless motors at the same time,

i need to control 4 brushless and i don't want to use a microcontroller for every motor, it will take a lot of space.

thx

Offline hudbrog

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Re: microcontroller to control 4 brushless simultanously
« Reply #1 on: November 05, 2008, 04:18:34 AM »
hi everybody,

does anyone know if there is a micocontroller that can control 4 brushless motors at the same time,

i need to control 4 brushless and i don't want to use a microcontroller for every motor, it will take a lot of space.

thx

Really depends.. How much phases (i.e. windings) each of your motors have? After that all you need is enough PWMs (or you can do it solely in software, with no hardware PWM, but that is not a good idea).
For example, you want to control three-phase BLDCs. For each you need 6 microcontroller outputs (better with PWM) and an input from shaft position sensors (to know which phase to enable next.. hall sensors as example). And at least 6 mosfets. For four of them - multiply all by four.
I.e. 24 PWM, lots of inputs (well, for example 3x4 = 12).
If it were for me, I would implement it on CPLD or FPGA. Imho the best way.
Otherwise you should look at Cypress PSoC (not sure if they'll work) or propeller chip.

Offline MaltiK

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Re: microcontroller to control 4 brushless simultanously
« Reply #2 on: November 05, 2008, 05:01:18 AM »
Picaxe28x1 Project Board (AXE020) has a built in slot for an L293D, which is 2 motors, but then youll have to use the TTL ports or portcs on the board to  control two more with another l293d externally, its very simple, if you decide to do this, I have a bunch of schematics and dummyproof instructions that were for me :P
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Offline mba7Topic starter

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Re: microcontroller to control 4 brushless simultanously
« Reply #3 on: November 05, 2008, 09:50:39 AM »
do you mean that if i use one big microcontroller and two L293D i can control my 4 brushless motors ?

Offline hudbrog

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Re: microcontroller to control 4 brushless simultanously
« Reply #4 on: November 05, 2008, 10:43:19 AM »
No, you can't. Brushless motors are a little harder to control than plain old dc motors. Why do you want to use em in first place?

Offline mba7Topic starter

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Re: microcontroller to control 4 brushless simultanously
« Reply #5 on: November 06, 2008, 03:17:25 AM »
i am making an equivalent to men vision system project in my study,

an eye will be a sphere with two dof and every dof will be controlled by a tiny brushless motor

Offline hudbrog

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Re: microcontroller to control 4 brushless simultanously
« Reply #6 on: November 06, 2008, 03:41:19 AM »
It is a really strange choice to control eyes. Maybe you should go for hobby servos? Those are cheaper, nuch easier to control, and you can directly set position for them. For brushless motor you'll have to add gearbox, and some kind of encoder to control shaft position... Stepper motor as a subtype of brushless motor will do, but still not the best choice for such task.

Offline Razor Concepts

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Re: microcontroller to control 4 brushless simultanously
« Reply #7 on: November 06, 2008, 07:38:48 AM »
Look at RC hobby-grade brushless speed controllers, they take the same pulses that servos do but instead they drive the motor.

 


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