Optimum radius of robust stability for Schur polynomials

The paper investigates the problem of the robust stability of Schur polynom ials. Recently, a new approach based on the Rouche theorem of classical com plex analysis has been adopted for the solution of this problem. In this pa per, an improvement of the previous solution is presented. This is the opti mum solution of the robust stability problem for Schur polynomials, which i s obtained by solving a minimization problem and is better than other metho ds in robust stability literature. Three numerical examples are given to il lustrate the proposed method.