Hardware Implementation of a General Purpose Fuzzy Controller

A general purpose, fuzzy logic-based controller is proposed. Its main features are low cost, high speed, and adaptability to different applications. The two first characteristics are obtained resorting to an active-rule driven strategy to implement simplified inference mechanism. Adaptability is insured by the capability to choose among different defuzzification methods. quent supports to give more importance to crisper, rather than fuzzier, consequents [3]. Defuzzification methods have also been proposed which take into account the shape of fuzzy sets. The Level Grading Method (LGM) uses expression (2) to evaluate the controller output, but with wi proportional to consequent supports in its activation levels [4]. Unfortunately, hardware implementation of this method is difficult even if triangular memberships functions are used. This is unlike Yager’s method (YM), where the rule conclusions ci are calculated according to the corresponding activation level [5]. For triangular fuzzy sets, the controller output again depends on two parameters: