Stability Margin of Systems with Linear Parametric Uncertainty

The paper deals with the problem of determining stability margin of linear continuous-time systems with parametric uncertainty. The coefficients of characteristic polynomial with linear affine dependency on system parameters are considered. The system parameters are supposed to vary in intervals with the endpoints parameterized by arbitrary functions that e.g. allows to consider cases where the nominal point does not lie in the middle of admissible intervals. An elegant solution, graphical in nature, based on generalization of Tsypkin-Polyak plot is presented.