On 11/29/2020 07:02 PM, Gene Heskett wrote:
I should be at about the servo tuning step by this time
next week, something I have only done with steppers, and
likely at less than optimum settings.
Is there a tut on adjusting such a servo?
You could look at my page on servo tuning at :
http://wiki.linuxcnc.org/cgi-bin/wiki.pl?PWM_Servo_Amplifiers
It is aimed at my PWM controller/PWM servo amps, but
generally goes through the steps.
My procedure has evolved a bit. What I do is set I and D to
zero and P low (5 - 50, depends on the
system) and then adjust FF1 while observing pid.nn.error
with Halscope, and also showing encoder velocity to have
something for the scope to trigger on. When you get the
error down to small value
(.001" or less) then you may want to add a TINY amount of
FF2 to help with the accel/decel transients.
You have to find a compromise here, as friction helps with
decel but hurts with accel.
Then, turn up P until some oscillatory behavior appears,
then add a little bit of D. If FF1 is good, then
you don't need P to be real high to get good following.
The general scheme changes a bit depending on whether it is
a velocity servo, torque servo or
a voltage servo that behaves kind of in between.
With a true velocity servo, FF1 does almost all the work,
and P can be quite low.
Jon
_______________________________________________
Emc-developers mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-developers
