Most of the Takagi-Sugeno Fuzzy (TSF) systems found in the literature have only used linear functions of input variables as rule consequent and can be called as TSF Models with Fixed Coefficient (TSFMFC). This paper presents TSF model with variable coefficient (TSFMVC) which can more closely approximate a class of nonlinear systems, nonlinear dynamic systems, and nonlinear control systems. It is also shown that TSFMFC is a special case of TSFMVC. Moreover Variable Gain TSF Controller (VGTSFC) is defined and it performs better, as shown by the simulation results, when compared with Fixed Gain TSF Controller (FGTSFC).
R. Rajesh and M. Kaimal, R., “Variable Gain Takagi-Sugeno Fuzzy Logic Controllers”, Informatica, Lith. Acad. Sci., vol. 17, pp. 427-444, 2006.