A singular value decomposition based closed loop stability preserving controller reduction method

In this paper a controller reduction method which preserves closed loop stability is described. A Lyapunov inequality based sufficient condition is proposed in the search of the reduced controller. The reduced controller leads to a stable closed loop system with guaranteed approximation quality. Furthermore, the proposed problem can be formulated as a matrix approximation problem which can be solved efficiently using singular value decomposition. Numerical application examples are shown in the end to evaluate the generality of the proposed reduction method.