> >The thread about temperature control remainded me a presentation
> >from Texas A&M in which fuzzy control was outperforming PID based
> >controller in a real application. If you search by the author name
> >Langari, i think it was 3-4 years ago you may get some papers to look
> >at it.
>
> >__Aydin
>
> As a graduate of Texas A&M (class of 93)  I do not recall any great interest
 in
> Fuzzy Control.  In fact when, I studied control theory at Texas A&M, the
> professor was not in favor of Fuzzy Control.  Fuzzy Control was seen as a
 sales
> tool to sell washing machines in Japan.  Fuzzy Control has its place, but it
 is
> not the great solution or replacement for PID control.  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.
>
> ---- Steve


If you check ME department you'll find some news about Dr. Langari,
he might have been a student back then.

I am not trying to sell fuzzy control alone as the greatest solution
at all. But I believe it is a very useful tool which can make a
bridge between modern and postmodern, intelligent, etc. control
techniques. In fact as a control engineer it hurts to see people keep
using PID which is not even defined for nonlinear systems. But it has
been used even in flight control with gain scheduling, btw which can
also be viewed as a fuzzy control. So in this group especially for
the hackers there are great adventures with it. You may go places no
one has gone before:)

I have been in control systems society for about 5 years. My
background is in control theory.

So your EE prof's comment on fuzzy control isn't suprising to me. In
1993 IEEE CDC, San Antonio, TX, biggest control conference. Bode award
winner Prof. Athans from MIT is giving his speech. His contributions
in optimal control are greatly valued. In his speech he blasted Japan
and so called intelligent, neuro-fuzzy, control. According to his expert
opinion, especially neurocontrol, was something like a great scam and
must have been kept out of control systems society. Funny but. the
inventer of fuzzy sets, Lotfi Zadeh happens to be his advisor from
Berkeley and for this reason fuzzy portion of it did not get much
critics from him.

He is not alone. Most of the control profs. with math background
don't like such ideas. If you try to prove by a real example it works
they might even get offended.

I had to ask myself why a person like Prof. Athens attacking some new
techniques and trying to stop its development. I didn't know the
answer but what I know as a fact that most of the industrial
applications do not use modern control because of the assumptions made
are too strong and don't fit most of the practical systems. Thus, those
fancy tools don't work. On the other hand, somebody, most of the
times happens to be from japan, comes up with a neurofuzzy control
scheme without any proof, in a tough real life example showing it
working. Open up a robot controller most of the time you will find a
PID derivative type of algorithm. I could not find any nonlinear
based, e.g., adaptive, robot controller in the market. There books
written about it though. IMHO, this may be the reason why some
control people got frustrated.



PS: Last year I saw Prof. Athans name on a neurocontrol paper :)

Regards,


__Aydin