In article .com,
Predictor wrote:
Ernest Christley wrote:
"Dan, did you ever get a chance to work with fuzzy logic?"

Pete Schaefer responded:
"I have. It's been a while. I'd never, ever use it on an airplane.
Maybe a washing machine controller or something like that. I'm not
saying that it can't be done, but just that it's a risky design
approach."


Why is fuzzy logic "risky"?

BECAUSE it _is_ fuzzy. grin

Seriously, the nature of fuzzy logic is that it it _not_ deterministic.
Given a specific set of inputs, you cannot predict exactly what the
fuzzy logic will do for every occurrence of those inputs.

Identifying and analyzing "boundary" conditions in fuzzy logic is
"difficult, at best". _at_ a boundary condition, there is no telling
how far back one must trace to find the 'bias' that changes the output,
when all 'intermediate' inputs are identical. Even worse, the decision
may be based on 'noise' in the system.

This like this can lead to "unexpected" behavior in "unusual" circumstances.



Pete Schaefer continues:
"There are other methodologies much better suited for aircraft."


Why are other methodologies "much better suited for aircraft"?


Because they're more "predictable". see above.

You *really* want to be able to predict what the control system will
do, under every possible combination of inputs.

While 'strange things' may happen, at least you can rely on the fact
that "given the same circumstances again", the *same* "strange thing"
will happen.

..