Krylov-based controller reduction for large-scale systems

In this paper, we introduce a computationally efficient controller reduction approach using a rational Krylov method. We show that a reduced-order controller obtained via a Krylov projection is guaranteed to match the desired full-order closed loop system response at shifts used in the Krylov reduction of the controller. Two different shift selection strategies are proposed. A numerical example illustrates the effectiveness of the proposed approach.