Robustness measure bounds for optimal model matching control designs

The theorems introduced by R.V. Patel et al. (1977) for multivariable linear quadratic state feedback design in the presence of perturbations are extended to optimal model matching control system designs. A robustness measure bound is introduced for optimal model matching control systems. Bounds are obtained for allowable nonlinear time-varying perturbations such that the resulting closed-loop system remain stable. Bounds on a special, but important class of perturbations, in which the perturbation is linear, are also derived