A new representation of Hinfini suboptimal controllers
Abstract
Elementary state-space concepts are used to derive a transparent solution to the stationary H control problem. The main contribution of this solution is a novel representation of suboptimal controllers in terms of a pair of parametric Riccati equations with a coupling constraint. Unlike the classical parametrization in terms of linear fractional transformation, this state-space representation has a homogeneous Riccati formulation which should help to make the most out of the suboptimal controller diversity. Potential applications include the design of reduced-order controllers and more generally the selection of suboptimal controllers to meet or optimize additional constraints.