A comparative study of two fuzzy control systems design

Two fuzzy controller design techniques are discussed. One is the so called standard or the online method in which the fuzzy rules are triggered based on the fuzzy associative memory (FAM). The FAM is in fact the organized form of fuzzy rules which may be obtained from the experience of an expert operator or by the method of rule generation based on learning from examples, as suggested in this paper. The other method is called the off-line method which is based on the calculation of fuzzy relation matrices (FRM). The calculation of FRM is based on Zadeh´s composition rule of inference. Each fuzzy input to the controller is basically composed of all the outputs to produce the corresponding FRM for that particular rule. This procedure is repeated for every input. Then an OR operator is performed to obtain a final FRM. Both of the fuzzy control design procedures are compared and contrasted in several aspects