A quick evaluation of stability hypercube and hyperball in polynomial coefficient space

Measures for Hurwitz stability of polynomials are discussed. The authors devise a simple method to estimate the robustness measures at a stable nominal polynomial. Two norms are employed, the l^∞- and l²-norms, which correspond to the stability hypercube and the stability hyperball in polynomial coefficient space, respectively. The result is that just inverting the Hurwitz matrix for the nominal polynomial yields estimates for the size of the hypercube and hyperball. The problem formulation is included. The main results and numerical examples are given