define PWM input for step response....

[ammjy]

Hello, EEVBlog Users ! Thanks you for click.

i don't have idea how i can define PWM input for matlab system identification toolbox.

i'm using matlab "system identification toolbox" for get transfer function of RC servo motor.

i already get very nice step response result of RC servo with 1->2ms PWM signal.

the problem is this..

input signal is PWM 1->2ms signal.

if, input signal is kind of voltage change like a 0 -> 5V. i can get transfer function directly.
but this is PWM signal...

can i use just PWM directly ? or i should convert PWM to some numbers ?

[Nitrousoxide]

Just an idea, perhaps you can convert the PWM signal to a control voltage by performing a low pass on the PWM. However, this will introduce a significant delay and attenuate any high-frequency changes, which may affect your input step signal.

Ideally, you would record the control voltage before PWM modulation.

[ammjy]

Thanks you Nitrousoxide !!
i already solved !

Thanks you for your comment.

in this case, i just use angle command.

i mean..

i gve 0.25 number for 1ms PWM.

then i can use just 0.25 !
 
Thanks you !