The Parameterization of all Disturbance Observers for Plants with State Disturbance

In this paper, we examine the parameterization of all disturbance observers for plants with any state disturbance. The disturbance observers have been used to estimate the disturbance in the plant. Several papers on design methods of disturbance observers have been published. Recently, the parameterizations of all disturbance observers for plants with any output disturbance and all disturbance observers for plants with any input disturbance were clarified. However, no paper examines the parameterization of all disturbance observers for plants with any state disturbance. In this paper, we propose parameterizations of all disturbance observers and all linear functional disturbance observers for plants with any state disturbance.