A novel approach to the analysis and synthesis of controllers for parametrically uncertain systems

This paper presents a novel characterization of Hurwitz polynomials, and demonstrates its usefulness in analyzing parametrically uncertain systems and synthesizing robust controllers for such systems. The characterization is a variant of the Nyquist stability theorem, but unlike this theorem, it can prove a polynomial is Hurwitz from only approximate knowledge of the polynomial´s phase at finitely many points along the imaginary axis