Computation of the robustness margin with the skewed μ tool

Methods for the direct computation of the maximal structured singular value (s.s.v.) over the frequency range require a recursive application of mu analysis. Introducing the nu measure as a skewed s.s.v., we point out that the problem can be solved by a single application of the nu tool. A mixed nu upper bound is then proposed, which provides a direct solution to the problem. The relationship between the mixed mu and nu upper bounds is moreover clarified. The nonnegativity of the sensitivity of the mixed mu upper bound is finally obtained as a corollary. (C) 1997 Elsevier Science B.V.