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pwm resolution-->position resolution?

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ahgu

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pwm resolution

Since i am using pwm or DAC to send the power signal to control motor?
Since the pwm or dac are 10bit resolution, (1k level) How would I know the position resolution I will get with 10bit?
The velocity res will be 0.1%, but what about positioning?
 

pissant

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pwm != position control, unless you are using some control logic between the pwm signal and the motor.

positioning accuracy will depend on your encoders which provide position/velocity feedback.
 

ahgu

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I understand that. I am asking the relationship between pwm steps(resolution) and the position resolution?

say you have 10bits 1024 steps, you can have 0.1% on speed control, but what about positioning??? say your encoder has 2000 pulses/rev.
 

bunalmis

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PWM resolution, indepented from Velocity or Position resolution.
Servo loop time very importand for control.
If your motor has big inertia you can use lower PWM resolution.


You can use 20 bit PWM but if your control algorithm is bad velocity or position err may be high.

+/- 1 or 0 position error possible by 8 bit PWM and good control algorithm.

PWM resolution increase the system stability. Reduce harmonic currents
and acustic noise.
 

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