Robust nonsingularity analysis using linear fractional transformation and its application to stability analysis

Abstract

A b s t r a c t In this paper, a procedure is described for converting a perturbed matrix with mixed unstructured and structured uncertainties t o the form of a Linear Fractional Transformation (LFT). Also, a criterion is given for keeping the nonsingularity of the perturbed matrix, provided it is nominally so. Moreover, based on the conversion method and criterion, explicit bounds on the Lime-varying uncertainties in continuous-time and discretetime systems are derived for robust stability.