Disturbance decomposition of time delay system by shadow robot based on network disturbance concept

This paper discusses the problem of time delayed control system with communication disturbance observer (CDOB) when the system suffers large external force. This method is based on the concept of network disturbance that consider the effect of time delay as a disturbance in acceleration dimension. CDOB estimate the effect of time delay to the system and using the estimation result compensate it. In practical application, disturbance observer (DOB) is used simultaneously with CDOB to compensate disturbances other than network disturbance, such as external force, friction, gravitation effect, etc. When such disturbance forces are quite large, the accuracy of network disturbance estimation is degraded. A method using shadow system is proposed to decompose the disturbances thus accurate time delay compensation can be achieved.