A design method for control system to attenuate periodic input disturbances using disturbance observers for time-delay plants

In this paper, we examine a design method for control system to attenuate periodic input disturbances using disturbance observers for time-delay plants. 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, parameterizations of all disturbance observers and all linear functional disturbance observers for time-delay plants with any input disturbance were clarified. If parameterizations of all such observers for time-delay plants with any input disturbance are used, there is a possibility that we can design control systems to attenuate input disturbances effectively. In this paper, to attenuate periodic input disturbances effectively, we propose a design method for control system using these parameterizations.