Comments for Project Blog

Comment on Improving the Beginner’s PID: Tuning Changes by Marcelo

Marcelo — Mon, 19 Nov 2012 21:49:18 +0000

The algebra is actually not correct. If both terms were equal, the result should be the same. Your ki is time dependent, which is why it cannot get out of the integrand. Still, the integral output term really is oi(t) = integral{ ki(t) * e(t) dt}.

Anyway, this is a nice fix and a very useful library.

Comment on Improving the Beginner’s PID: Initialization by Mike

Mike — Wed, 14 Nov 2012 19:22:17 +0000

Nevermind, needed to read one line down. I see where you are detecting the transition.

Comment on Improving the Beginner’s PID: Initialization by Mike

Mike — Wed, 14 Nov 2012 19:13:46 +0000

It looks like if SetMode(AUTOMATIC) is repeatedly called the PID will continually initialize. I need to add a variable to detect if the previous Mode was MANUAL and only then initialize.

Comment on Improving the Beginner’s PID – Introduction by Greg

Greg — Sun, 11 Nov 2012 09:50:42 +0000

Very nice tutorial, thanks so much! Is there any chance for a pdf version?

BR,

Greg

Comment on Improving the Beginner’s PID – Introduction by Sean

Sean — Sat, 10 Nov 2012 00:28:50 +0000

Hi Brett,

Without exagerating, I think this is one of the best blog articles I have ever read. It has shown me more about PID control than any robotics book with all of its theory has shown me.

Thank you for all of your help!!!!

Comment on Improving the Beginner’s PID: Direction by Alex

Alex — Fri, 09 Nov 2012 15:55:04 +0000

Brett,

This is very good. Thanks for sharing!

Comment on Improving the Beginner’s PID: Initialization by Juan

Juan — Wed, 07 Nov 2012 07:33:36 +0000

I have the same question as Paul; why do you set Iterm = Output if Output has not been updated since you were last in manual mode?

Shouldn’t Output = 0 and then start integrating as soon as the next error is calculated on the new output?

Thanks for putting in the effort of explaining PID in such an intuitive way. I have been on control courses which leave you with less understanding!

Comment on Improving the Beginner’s PID: Direction by John Sloan

John Sloan — Tue, 30 Oct 2012 20:52:57 +0000

Wanted to express my appreciation for this excellent series of articles. Control theory is not my area. But between these and Tim Wescott’s “PID without a PhD” I was able to cobble something together and make it work surprisingly well. Challenging since I couldn’t use floating point nor even integer multiply or divide. But with some magic to round towards zero, managed to make it all work with just shifts, adds, and subtracts. Thanks again!

Comment on Improving the Beginner’s PID: Direction by Kurt

Kurt — Thu, 25 Oct 2012 17:28:19 +0000

Now I feel confident about the topic. You have helped me alot. Please continue this series and included further topics.

Comment on Improving the Beginner’s PID: Reset Windup by Dave Keenan

Dave Keenan — Sun, 21 Oct 2012 03:48:43 +0000

Did you consider using the “velocity form” of the equations so you only have to clamp the output. See http://en.wikipedia.org/wiki/Talk:PID_controller#Velocity_Form_Pseudocode