Robust, non-fragile and optimal controller design via linear matrix inequalities

In this article, we introduce a robust nonfragile state feedback controller which is also optimal with respect to a quadratic performance index, using linear matrix inequalities (LMI). The uncertainties are assumed to be polytopic, both in the controller gains and the system dynamics. A numerical example is presented to demonstrate the efficiency of this method, and the controller turns out to be robust with respect to the uncertainties in the plant and the controller.