Robust controller design for fuzzy parametric uncertain systems

In this paper, a method is proposed to design a robust controller for fuzzy parametric uncertain systems. An uncertain LTI system with fuzzy coefficients is referred as fuzzy parametric uncertain system. In this work the fuzzy coefficients are approximated by intervals (crisp sets) using the nearest interval approximation approach to get an interval system. Then a robust PI/PID controller is designed using necessary condition and sufficient condition for stability of interval polynomial. These conditions, obtained using the results of Nie are used to derive a set of inequalities in terms of controller parameters and then are solved to obtain a robust controller. The numerical examples and simulation results show the efficacy of the proposed method for design of robust controller for fuzzy parametric uncertain systems.