Stability robustness of linear systems to real parametric perturbations
Laurent El Ghaoui, Stephen Boyd · 1990
Linear time-invariant systems subject to real, parametric variations are considered. The problem of computing the half-sidelength 1/ mu /sub infinity / of the largest stability hypercube in the parameter space is formulated in a frequency-independent way. The frequency-dependent approach developed in mu analysis is impracticable, because mu /sub infinity / is a discontinuous function of frequency. The authors derive an accurate upper bound for mu /sub infinity /, using block-diagonal scaling of the largest singular value of a real, frequency-independent matrix M. The optimal scaling is found using quasi-convex optimization. A numerical example illustrates the method.>