A note on the Liénard-Chipart criterion and roots of some families of polynomials

Renato B. Bortolatto¹

¹ UTFPR

Resumo

We present some inequalities that provide different sufficient conditions for an univariate monic polynomial to be Hurwitz unstable. These are motivated by difficult control problems where direct application of the Liénard-Chipart criterion is not feasible. Hurwitz stability of some polynomials of degree five is also discussed. These results may be interpreted as stability results for some interval polynomials.