A two-stage output feedback design

The problem of output feedback control design for discrete systems with fast and slow modes is considered. It is shown that, when the effect of the slow mode on the fast mode is linearly related to the slow output vector, the control design can be implemented in two stages by using separate gain matrices. The new output feedback design yields first-order perturbations in the behaviour of the discrete system. A ninth-order boiler model is used to illustrate the design procedure.