FPGA Based Hierarchical Fuzzy System

Multivariable fuzzy system implementation suffers from amount of computation resulting from the high number of rules especially for large number of input variables. As number of inputs increases, the situation becomes worse because the number of rules increases exponentially with respect to input variables resulting in problem commonly called “rule explosion problem”. Another problem related to multivariable system is the complexity of rule construction of high dimensionality fuzzy system. Hierarchical system breaks high dimensionality fuzzy system into several low dimensional fuzzy systems such that the number of rules has linear proportion with the number of input variables. In this paper, hardware implementation of fuzzy system with hierarchical structure is performed to obtain powerful system take the advantages of both hardware speed and low dimensionality processing reduction of hierarchical implementation.