Stability Analysis Method for Delta-Operator Diamond Polynomials via Directional Stability Radius

Abstract

It is known that for uncertain systems with delta-operator diamond characteristic polynomials, extreme point results do not hold, making their stability test a tough work. In this paper, we propose a stability analysis method for the system using directional stability radii which are capable of measuring stability margin for coefficient perturbations with restricted directions. The feature of the method is that the larger stability margin becomes, the easier the job is.