Sufficient Stability Criteria for Real Polynomials via Parametrized Schur Property

Abstract

An attempt is made to improve well-known sufficient Schur stability conditions for real polynomials. The existing conditions are easy-to-check but conservative and used therefore as a preliminary test before resorting to exact ones. Pivotal to the scheme is an equivalence relation between Schur property of a polynomial and that of another one including a single free parameter. The resulting freedom enables to generalize the conditions and thereby lessen their conservatism. Numerical examples illustrate gains in sharpness attained by the proposed approach over existing conditions.