A reduction method of steady-state errors in time-delay systems with communication disturbance observer

This paper proposes a reduction method of steady-state errors in time-delay systems with communication disturbance observer (CDOB). A time-delay compensation method based on network disturbance (ND) concept and CDOB has been proposed and applied to various time-delay systems. The validity has been verified by experimental results. On the other hand, a defect of the method on steady-state characteristics has also been pointed out. System model errors lead to serious steady-state errors in the method. Therefore, some approaches to address such a problem have been studied so far. In this paper, a novel and simple approach to handle the steady-state error problem is proposed. The proposed method reduces steady-state errors by designing system models appropriately. Design procedures of the method are also studied. Finally, it is validated by simulation studies.