1. Institute of Automation, Chinese Academy of Sciences, Beijing 10t0080, China 2. Department of Mechanics and Engineering Science, Peking University, Beijing 100871, China
Abstract:
For the two fourth-order polynomials a ( s ) and b ( s ), the Hurrwitz stability of their convex combina tion is necessary and snfficient for the existence of a polynomial c (s) such that c ( s ) / a ( s ) and c ( s ) / b ( s ) are both strictly positive real.