DC Motor Speed Control Using PWM

[baileychic]

This is a question related to DC Motor Speed Control Using PWM.

I need precision speed control. How to achieve it. I am making a small coil winding machine for a client. He is going to use two DC motors. One for the main winder and another for sliding the wire to and fro so that the coil gets polaced side by side during winding on the bobbin.

The bobbin length, height, width and wire guage are entered using buttons and based on these data I need to control the wire slider motor. When one turn of the winding gets completed then the motor has to turn equal to the guage of the wire and when end of the bobbin is reached then it has to turn in the opposite direction till another end of bobbin is reached and this continues till winding count completes.

I am using ATmega8A and mikroC PRO AVR.

How to control the slider motor speed so that it turns equal to one wire guage once when one winding is completed ?

 

[FvM]

Think about incremental encoders for both drives.

You don't actually need precision speed control rather than accurate relative position control.

 

[baileychic]

@FvM

Okay. Thank you. I will ask my client if he can use incremental encoders for both motors.

I know how encoders works. I have written a code for coil winder using one encoder for main winding motor but I want to know how two encoders can be used one for each motor that is for main winding motor and slider motor ? The problem is if say the main motor makes one winding of coil on the bobbin but the slider motor has to rotate only a little because the guage of the wire is say 1mm. So, to achieve 1mm displacement on the bobbin say the slider has to rotate 2mm but that will not give any encoder pulses ?

 

[FvM]

Obviously, you need sufficient encoder resolution. I would consider encoders on the motor shafts and gears according to the intended speed, torque and position resolution.

 

[KlausST]

Hi,

Or consider to use stepper motors.
But this is against your requirement for "PWM speed control"

Or one DC motor for coil rotation, one encoder at it's shaft and one stepper for the X movement.
The X movement motor usually doesn't need high torque. ... and the stepper gives perfect RPM and does not suffer from forward/return delay.

Klaus