On the computation of the optimal H∞ norms for two feedback control problems Original Research Article

Numerical computation of the optimal H∞ norms for the state feedback and the output feedback control problems is considered. In 1989, Doyle et al. derived, for a given parameter r > 0, necessary and sufficient conditions under which an admissible output feedback controller exists, as well as conditions for the existence of a state feedback controller. We explore numerical methods to find the infimum of parameter r that satisfies those conditions.