PID tunin... Your experience.

[samco]

So I have taken the leap into servos. DIY style. I am using emc2 as shown here.
http://www.cnczone.com/forums/showth...368#post215368

I have not found much info on tuning pid loops.. Normally people have said - 'I just keep fiddling with the numbers until I get the response I want.

Now I just closed the loop and have been experimenting..(Pretty damn cool btw). I have so far used the Ziegler-Nichols method.. this involves increasing P until the system oscillates - then measuring the period of oscillation. This is then put thru a formula to get the I and D values. It is at the bottom of the page here.
http://linuxcnc.org/docs/html/motion...ory/index.html

The other way I have heard of - also on the above page - involves increasing P until oscillation - then increasing I until it stops - then increasing D until the response is achieved..

I have not gotten to the point of graphing commanded Vs actual position yet to see. When I get to that point - how do I know what numbers effect what? I also have control over ff0,ff1 and ff2. (feed forward)

What are others experience?

thanks

[Karl_T]

Another article to read that may help:
http://www.machinedesign.com/ASP/vie...rticleId=55300

Karl

[samco]

thank you

That is a very infromative article.

sam