ABSTRACT
This chapter is devoted to an example of system modeling in which fuzzy logic is put into effective use. We consider a system as an input-output map: y = f(x). We assume that the internal structure of the system is unknown, but qualitative knowledge about its behavior is available, say, under the form of a collection of “If...then...” rules. The problem is to construct a mathematical description of the system, based upon available information, so that it will represent faithfully the “true” system. The construction process consists of translating linguistic rules into mathematical expressions using fuzzy sets and fuzzy logic, and defuzzifying the combined fuzzy output. The systems so obtained are shown to be within a class of designs capable of approximating the “true” input-output relation to any degree of accuracy.
