On robust observer compensator design

Abstract This paper presents, for the first time, a unified, explicit and restriction free set of design formulas for Kalman type and Luenberger type state observers and function observers, with arbitrary poles. In addition, a new, explicit and deterministic observer pole selection method for recovering the robustness of a direct state feedback system is also proposed. Two design examples are given in this paper. These examples demonstrate the advantages of this robust recovery method. The examples also show that both the Luenberger type observers and the function observers generally have better stability margins. This design methodology enables the design objectives of robustness, order reduction and performance to be considered together in terms of observer pole selection.