A design framework for overlapping controllers and its application

This paper presents a new practical framework for decentralized output feedback design with overlapping information structure constraints. In contrast to the earlier works, the proposed method removes restriction in the control design algorithm by utilizing congruence transformations, simplifications and the reciprocal variant of the projection lemma. This leads to a less conservative solution than the previous design methods because the choice of some design parameters by trial and error is eliminated. Moreover, in some cases, the structural constraint of having a diagonal Lyapunov function in linear matrix inequalities (LMIs) is removed. The results are then extended to capture a more general scenario of output feedback control design for nonlinear interconnected systems. The validity of the proposed approach is demonstrated through applications to an industrial utility boiler and to a multi-area power system.