On stability margins of the Fiat Dedra engine model

We evaluate the stability margin of a Fiat Dedra engine model to explore possible applications of theoretical achievements in the parametric approach to robust control problems. The study is based on two versions of the model with uncertainties. One is the original model, which has a multilinear characteristic polynomial, while the other is an affine-linearized model which is obtained by the affine linearization technique proposed in the paper. By applying some newly developed theoretical tools in the literature, the stability margins of the affine-linearized model in terms of the ¿¿8 norm and the ¿¿2 norm and the stability margin of the original model in terms of the ¿¿8 norm are obtained