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 μ analysis. Introducing the v measure as a skewed s.s.v., we point out the problem can be solved by a single application of the v tool. A mixed v upper bound is then proposed, which provides a direct solution to the problem. The relationship between the mixed μ and v upper bounds is moreover clarified. The nonnegativity of the sensitivity of the mixed μ upper bound is finally obtained as a corollary.