Applicability of the fuzzy operators in the design of fuzzy logic controllers

this new field known as Expert Control. Fuzzy Logic Controllers (FLCs), initiated by Mamdani and Assilian in the work [Mam75], are now considered as one of the most important applications of the Fuzzy Set Theory suggested by Zadeh in 1965 ([Zad65]). FLCs are knowledge based controllers usually derived from a knowledge acquisition process or automatically synthesized from a self-organizing control architecture ([Bon94]). A study of the different roles played by the fuzzy operators in fuzzy control is developed in this paper. The behavior of a very big amount of fuzzy operators is analyzed and a comparison of the accuracy of many fuzzy logic controllers designed by means of these operators is carried out. In order to do that, a comparison methodology is defined and two fuzzy control applications are selected, the Inverted Pendulum problem and the fuzzy modeling of the real curve Y=X. During the past years, many applications of Fuzzy Logic Control have been developed successfully (see [Hir93,Bon94,Lee90,Ber92]) and FLCs have been proved to be superior in performance to conventional systems in many applications.