Pages: 1 [2]   Go Down
Author Topic: How to use Arduino to control a brushless motor for camera gimbal  (Read 7229 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Faraday Member
**
Karma: 62
Posts: 3077
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Are they "ordinary" brushless motors ?   I find it hard to see how they can be driven in that way.  Maybe it is actually some obscure kind of brushless stepper motor.
Logged

Offline Offline
Full Member
***
Karma: 2
Posts: 213
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

A stepper motor is always brushless smiley-wink
Think of it as a 3 phase stepper instead of 2 or 4 phase steppers.

@tylernt
If you'd like to tinker a bit with the idea, just slaughter some PC cooling fans ( eg. from old PSU )
They usually have a high winding resistance. A 12V fan would probably work directly with the 5V arduino pins, but don't take my word for it!

I don't think you'd need an encoder or anything.  Just let the IMU do all the work.
« Last Edit: October 10, 2013, 03:53:02 am by o_lampe » Logged

It's not my fault when my Posts are full of Errors. This stupid autocorrection from my browser is set up for german grammar.

Offline Offline
Full Member
***
Karma: 2
Posts: 213
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Just found out which driver circuit the open-source BLDC gimbal "AlexMOS" guys are using:
http://www.alldatasheet.com/datasheet-pdf/pdf/22545/STMICROELECTRONICS/L6234.html
Includes freewheeling diodes and current sensing.
Available in 20 pin DIP smiley-grin *hint*
Logged

It's not my fault when my Posts are full of Errors. This stupid autocorrection from my browser is set up for german grammar.

Offline Offline
Newbie
*
Karma: 0
Posts: 6
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Just found out which driver circuit the open-source BLDC gimbal "AlexMOS" guys are using:
http://www.alldatasheet.com/datasheet-pdf/pdf/22545/STMICROELECTRONICS/L6234.html
Includes freewheeling diodes and current sensing.
Available in 20 pin DIP smiley-grin *hint*
So you knew how to solve the problem with BLDC?  smiley Can you take a tutorial for me?
Logged

Offline Offline
Full Member
***
Karma: 2
Posts: 213
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Just found out which driver circuit the open-source BLDC gimbal "AlexMOS" guys are using:
http://www.alldatasheet.com/datasheet-pdf/pdf/22545/STMICROELECTRONICS/L6234.html
Includes freewheeling diodes and current sensing.
Available in 20 pin DIP smiley-grin *hint*
So you knew how to solve the problem with BLDC?  smiley Can you take a tutorial for me?

Sorry my friend,
I have no hands on experience with that stuff. I just gave my 2 Cents. Try out a small fan Motor from a CPU cooler, their winding resistance might be high enough to drive them directly with a arduino. Start with two phases at first. See what happens when you change PWM ratio for one phase. Use a potmeter on an analog Input to change pwm ratio on the fly.

A full test setup would have three potmeters for three phases. Find out a pattern to rotate the fan slowly.

Good luck
O_Lampe
PS: It might be necessary to switch polarity for the phases too. Then ofcourse you'have to recalculate your pwm, since the duty cycle would change too.
« Last Edit: October 15, 2013, 12:52:39 pm by o_lampe » Logged

It's not my fault when my Posts are full of Errors. This stupid autocorrection from my browser is set up for german grammar.

Lacey, Washington, USA
Online Online
Edison Member
*
Karma: 162
Posts: 2490
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Brushless DC motors have stationary electromagnets, so it might be possible to rewind some with more turns of finer wire. No worries about balance, then, other than getting the same number of windings.

If you have some kind of optical encoder on the shaft, you'd have rotational feedback for the Arduino to calculate what voltage/current/PWM each phase requires.
Logged

Steve Greenfield AE7HD
CET Consumer Electronics and Computer
Please don't read your attitudes into my messages

Offline Offline
Faraday Member
**
Karma: 62
Posts: 3077
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

The optical encoder attached to a device intended to turn,   is unlikely to have the resolution to point a camera accurately.
Logged

Lacey, Washington, USA
Online Online
Edison Member
*
Karma: 162
Posts: 2490
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Presumably this is geared down.
Logged

Steve Greenfield AE7HD
CET Consumer Electronics and Computer
Please don't read your attitudes into my messages

Pages: 1 [2]   Go Up
Jump to: