Aydin Yesildirek wrote:
>
> > > > Pease Porridge of
> > > > Electronic Design ran a contest for a Fuzzy Control system that he
> > could not
> > > > duplicate or exceed the performance of.  He won every challenge using
> > op-amps
> > > > and classic control theory. Fuzzy Control and Fuzzy Logic has had lots
> > of
> > > > boasting and very little real substance.
>
> > When ... developing Fuzz-C we looked hard for applications
> > where fuzzy worked as well or better than conventional PID. When we did
> > we found that PID was highly optimized for a narrow range of
> > applications and fuzzy was a more general case.
> >
> > For example look at the momentum difference in an aircraft control system
> > after the fuel stored in the wings has been burned in flight. A PID control
> > loop in such a system is very hard to tune.
>
> It may not be fair to compare PID vs. fuzzy. The biggest strength or
> advantage you will obtain with a fuzzy logic is the range of
> applications, the ability not only to have a competitive performance
> where PID work well but also acceptable results in some applications
> PID, or any other conventional control methodology, poorly works or
> does not work at all.
>
> But it may not be the most precise controller you can come up with
> when you have other alternatives. Nevertheles, it is very robust and
> simpler to implement.
>
> __Aydin
Agreed.

The main thing about PID's popularity is that it is well known by the
people working in the field (the good ol' technicians) and easier to
implement, because you know it. Fuzzy is old, but also new. Designed a
long time ago, took a while to get popular with the Japanese etc. , but
us westerners never really bothered with it, did we?

Thats about as much as I know - so I stand corrected!
--
Eric van Es               | Cape Town, South Africa
mailto:vanes@ilink.nis.za | http://www.nis.za/~vanes
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