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

The authors present a novel characterization of Hurwitz polynomials and demonstrate 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 that a polynomial is Hurwitz from only approximate knowledge of the polynomial's phase at finitely many points along the imaginary axis. Applications to robust stability analysis and controller synthesis are presented along with numerical examples showing the theorem's versatility.<
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