> Please show we a PIC using fuzzy logic that does a control application
better
> than a classical control circuit.  Classical control systems have been in
> existence since the 1800's.  They are not inherently unstable and they do
not
> operate poorly.

PID is unlikely to be replaced by fuzzy. Proving that fuzzy is good does
not
prove that PID is bad. Fuzzy is another tool for problem solving. It can
be used to solve non-linear control problems very well. There is an example

in Circuit Cellar a couple years ago of a home environment control system
that used the 16C74 as a controller for both air conditioning and heat.
This
controller treated time as a fuzzy input and suggested a variety of ways to

add green rules to minimize energy usage. The fuzzy control rules in this
sytem follows;


 FUZZY room_control
   {
      IF room IS cold THEN
          ac   IS OFF
          heat IS ON

      IF room IS normal THEN
           ac   IS OFF
           heat IS OFF

      IF room IS hot THEN
           ac   IS ON
           heat IS OFF
      IF room IS cold AND hours IS morning THEN
           heat IS OFF
      IF room IS cold AND OutsideTemp IS hot THEN
           heat IS OFF
      IF room IS hot AND OutsideTemp IS cold THEN
           ac IS OFF
   }

> The cruise control in your car is a good example.  My cruise  control
> works great, operates smoothly, is safe, stable and uses classical
> control systems.

The cruise control on many cars use either fuzzy or setpoint tables a few
use PID and deal with the changing mass problem with additional parameters.

>
> If you are interested in a critical view,  view the URL below.  Bob
Pease, the
> author of Pease Porridge, tackles some Fuzzy control systems.
  http://www.national.com/rap/Application/0,1127,25,00.html

Bob Pease regularily acknowledges that fuzzy is well suited to non-linear
systems.

I have worked with both types of control systems. Given a problem
in the future I will happily use which ever is appropriate. Fuzzy logic
has added lingustic variables to the tools that we can use.

Walter Banks