PID?

floodhound

I am transplanting the BS2SX with the propeller chip and I wanted to know if there is a PID source code. I remember learning tremendously form the PID used in a book from parallax. Just wanted to know if the code could be translated – remember I am learning slowly so not to complex if you are going to help.

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My web site -- > www.floodhound.com <-- take a look if you like

Paul Baker

Yes, Andy Lindsay has posted code for a Propeller follower bot using PID, check out the PEKbot section of this thread: http://forums.parallax.com/showthread.php?p=617192

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

floodhound

Thanks a bunch

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My web site -- > www.floodhound.com <-- take a look if you like

Al Booth

I've been looking at the PID.Spin file in the PEKBot code and have a question. The file shows this code in the "derivative" section:

' Derivative
temp := f.FSub(E, Ep) ' ΔE = (now) - E(old)
temp := f.FDiv(E, dt) ' ΔE/Δt
D := f.FMul(kd, temp) ' D = kd

deSilva

I should think so, too...
Whatever the math be, it makes no sense to assign to temp twice..

One explanation could be, that E is not E as the comments say, but has already been changed to (now)-E(old) in instructions before, so obsoleting the first line...

Andy Lindsay (Parallax)

At first glance, it looks like I added disabled the derivative calculations.· Boarding a flight now, will check when I get home, and probably correct the code.

Andy

Update 8/23/07 - Corrections and testing in progress; hope to finish this weekend.

Update 8/27/07 - Corrections completed.··Updated PID object attached.· Also attached is an archive for examining the PID calculations for verification. "Test PID.spin" is the archive's top file.

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Andy Lindsay

Education Department
Parallax, Inc.

Post Edited (Andy Lindsay (Parallax)) : 8/24/2010 6:47:19 PM GMT