I can't seem to find any detailed example of fuzzy control on the net

From: Ephestione (ephestione.donotbotherme@yahoo.com)
Date: Mon May 28 2001 - 07:13:54 MET DST

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    I study Dentistry, and, even if it could seem absurd, I need to catch
    the FL control meaning to develop -even if only theorically- an expert
    system to study the cefalometric measurements of a population, so to
    see who are the ones in the "normal" range and the ones who aren't..
    based on a series of rules about bone angles and lenght and so on --
    this is all for my graduation work.

    Well for now I am looking for an example of applicated fuzzy control..
    about everything, but just a simple example to make FL clear. I tried
    myself to develop a fuzzy control algorithm, to make a washing machine
    open or not the box of the soap, depending on the water tank (say 20
    liters) being more or less full, and anyway open it unconditionally
    after 4 minutes. This obviously just to see if I was able to start
    from scratch.. well I got stuck after the composition (I followed the
    official FL FAQs).

    These were the rules I made:

     - IF the watertank is full THEN the soapbox is open

     - IF the watertank is empty THEN the soapbox is closed

     - IF the timer is ringing THEN the soapbox is open

    being these the functions I made:

     - full(x) = x/20 ;water tank is 20 liters

     - empty(x) = 1 - x/20

     - ringing(x) = {0, if 0=< x <= 220secs ;4 mins = 240 secs
                            x/20 - 11, if 220< x <= 240 secs }

    I think I can only use the MAX-MIN method here to make the 4mins timer
    rule to work.

    So... after I inferenced, and composed, I get a fuzzy(::unknown
    variable::) function (for each value of watertank level and timer
    seconds) which, since I only need to know wheter the soapbox has to be
    open (1) or closed (0), I have to defuzzify...

    I get lost here!

    I mean.. the FAQs give me no info when I have to use Average of maxima
    (is it only used in combination with MAX-MIN method?) or Centroid (is
    it only used in combination witrh PRODUCT-SUM method?) on a function
    which values should only vary in {0,1}...

    Am I wrong?
    I feel just lost.

    BTW I just started from scratch 2 weeks ago, not even knowing what FL
    was... and I need something to tell the orthodontics professor for
    thursday ;-)
    I mean, my work will be totally theorical, but this technical detail
    is necessary at the beginning to introduce me to the subject.
    So... just a "debug" of the "thing" I made, or an URL to everythig
    explaining in detail the development of a very very simple fuzzy
    controller would make the deal :-}

    Thank you even only for reading till here

    Regards

    ----------
    Ephestione

    "Mommy the garbage man is here!" "Tell him we don't want any"
     - Groucho Marx

    ephestione at yahoo dot com

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