Robust Schur stability of interval polynomials

The investigation of Schur stability using a Kharitonov parameter box is discussed. The discrete counterpart of Kharitonov´s theorem is obtained. The solution is based on the use of the Hollot-Bartlett-Huang theorem and the Hollott-Bartlett theorem. This made it possible to test for Schur stability only a subset of the edges. The Schur testing of the required edges of the cube is performed using three different methods, namely, the critical edge polynomial, edge stability as an eigenvalue problem, and edge stability using colinearity conditions. Comparison of these three methods is presented. It is believed that, with the Schur testing of the minimum number of edges and the use of the critical stability constraints, minimum computational effort can be achieved