Analysis of interactions in MIMO Takagi-Sugeno fuzzy models

Input-output interactions in the inherently nonlinear Takagi-Sugeno (TS) MIMO fuzzy models can not be analyzed by using standard methods such as the relative gain array (RGA). Two methods are proposed that exploit the specific TS structure. The first one is based on a number of RGAs which can indicate sufficiently well the interactions in the model. Another tool to analyze input-output interactions is the output sensitivity, computed as a partial derivative of the output with respect to the considered input. The use of these techniques is illustrated with the help of a TS fuzzy model of a high-purity distillation column.