The parametrization of all disturbance observers for time-delay plants

In this paper, we examine the parametrization of all disturbance observers for time-delay plants. The disturbance observers have been used to estimate unknown disturbance in the plant. Several papers on design methods of disturbance observers for time-delay plants have been published. However, no paper examines the parametrization of all disturbance observers for time-delay plants. In this paper, we propose the parametrization of all disturbance observers for time-delay plants and that of all linear functional disturbance observers for time-delay plants.