Closed-Loop Structure of Discrete–Time H∞ Controller

This paper is concerned with the investigation of the closed-loop structure of a discrete–time H∞ control system. It is shown that discrete–time H∞ controller is represented, like Linear Quadratic Gaussian control, as a pseudo state feedback, that is, a state feedback interconnected with an observer. However, in the discrete-time H∞ control problem the control structure is more complicated since we cannot choose the state feedback and the observer independently.