Regional eigenvalue-clustering robustness analysis for singular systems with structured parameter perturbations

In this paper, under assumptions that the nominal linear singular system is regular and impulse-free and has all its finite eigenvalues lying inside c ertain specified regions, a sufficient condition is proposed to preserve th e assumed properties when the structured parameter perturbations are added into the nominal singular system. No restriction is imposed on the shapes o f the specified regions. The proposed method is applicable to both the cont inuous-time case and the discrete-time case. When all the finite eigenvalue s are just required to locate in the stable region, the proposed criterion will become the stability robustness criterion. By mathematical analysis, t he presented criterion is proved to be less conservative than the existing criterion reported recently.