Simplifying fuzzy rule base of multiple input multiple output systems by constructing multi-layer fuzzy controller

In conventional rule based fuzzy control systems, the rules have the form of “IF <condition> THEN <action>.” The number of rules increases exponentially as the number of system variables, upon which the fuzzy rules are based, is increased. Some papers have showed that, by structuring the rules in a hierarchical way, the total numbers of rules was a linear function of the system variables. In this paper, it was shown that the number of rules could still be reduced to minimum numbers by employing the same fuzzy rule set at every level