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Topic: How to use Arduino to control a brushless motor for camera gimbal (Read 8923 times) previous topic - next topic

michinyon

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.

o_lampe

#16
Oct 10, 2013, 10:47 am Last Edit: Oct 10, 2013, 10:53 am by o_lampe Reason: 1
A stepper motor is always brushless ;)
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.
It's not my fault when my Posts are full of Errors. This stupid autocorrection from my browser is set up for german grammar.

o_lampe

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

takeshi3491


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 :D *hint*

So you knew how to solve the problem with BLDC?  :) Can you take a tutorial for me?

o_lampe

#19
Oct 15, 2013, 07:49 pm Last Edit: Oct 15, 2013, 07:52 pm by o_lampe Reason: 1


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 :D *hint*

So you knew how to solve the problem with BLDC?  :) 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.
It's not my fault when my Posts are full of Errors. This stupid autocorrection from my browser is set up for german grammar.

polymorph

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.
Steve Greenfield AE7HD
Nick Gammon on multitasking Arduinos:
http://gammon.com.au/blink
http://gammon.com.au/serial
http://gammon.com.au/interrupts

michinyon

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

polymorph

Steve Greenfield AE7HD
Nick Gammon on multitasking Arduinos:
http://gammon.com.au/blink
http://gammon.com.au/serial
http://gammon.com.au/interrupts

PoppyAnn

#23
Oct 01, 2014, 11:56 am Last Edit: Oct 01, 2014, 12:05 pm by PoppyAnn Reason: 1
Has no one on here ever heard of a brushless gimbal motor? the reason for using a brushless motor on a gimbal is that they are much faster and smoother than any servo, they are available from most good radio control model shops, here are a couple of cheep ones from hobby king :-
https://www.hobbyking.com/hobbyking/store/__62564__2206_140Kv_Brushless_Gimbal_Motor_Ideal_for_GoPro_style_Cameras_UK_Warehouse_.html



https://www.hobbyking.com/hobbyking/store/__57964__2804_210Kv_Brushless_Gimbal_Motor_Ideal_for_GoPro_to_Compact_Style_Cameras_UK_Warehouse_.html

there is no encoder except for a 3 axial accelerometer and the brushless motor controller, the motors are used on a one to one ratio no gearing is used, these type of brushless motors are of a different type of motor as they have been wound with many coils of fine wire not as normal ones which have few coils of heavy wire.

I hope this may help people who have not come across these type of motors before.

regards Poppy Ann.

.

tylernt


Has no one on here ever heard of a brushless gimbal motor?
No, but we have now!

I see one of the BGM controllers sold by HK uses an ATmega328, so rolling your own with an Arduino should be very possible.

PoppyAnn

you can buy a complete gimbal with motors and controller for around £36 from banggood :- http://www.banggood.com/FPV-2-Axis-Brushless-Gimbal-With-Controller-For-DJI-Phantom-GoPro-3-p-908068.html




I have a couple but not used them yet hopefully i will get to use one soon.
regards Poppy Ann

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