The Role of Defuzzification Methods in the Application of Fuzzy Control

Abstract In this article the role of defuzzification methods in the application of fuzzy controllers is adressed. In most applications described in literature the concepts of the fuzzy controllers used are presented without motivation. The defuzzifier of a fuzzy controller can deteriorate a great deal of the results achieved by the inference of fuzzy rules. Therefor a closer look at the influence of this specific part of the fuzzy controller is worthwile. It appears that the application of a specific defuzzification method can reduce completely the fuzziness of the controller. Otherwise, it is possible to use crisp representations of fuzzy sets and still being able to realize a fuzzy character of the controller. Examples are given which show the (dis)advantages of several defuzzification methods.