Tuning and analysis of a fuzzy PI controller based on gain and phase margins

The nonlinearity of the simplest fuzzy PI controller with different inference methods has been discussed and it shows that Mamdani's minimum inference method is the most general inference method for the fuzzy PI controller. In addition, a novel tuning method based on gain and phase margins has been proposed to determine the weighting coefficients of the fuzzy PI controllers. With the proposed tuning formula, the nature of the fuzzy PI controller has been analyzed and it shows the desired characteristics in terms of gain and phase margins when controlling linear plants. Numerical simulations are presented to show the validity of the proposed tuning method.