AN INTRODUCTION TO THE S. S. V

The aim is to introduce in a rather qualitative way the s. s.v. as a tool for the study of the stability of a closed loop in the presence of a structured model perturbation. One focuses in this section on the stability property inside the left half plane. Other regions of the complex plane will be considered in the following section. For the sake of clarity, the first subsection presents the special case of a closed loop subject to parametric uncertainties. The general case of parametric uncertainties and neglected dynamics is treated in the second subsection. The third subsection is devoted to a technical, but practically important issue, namely the choice of the weights on the model uncertainties.