Experimental validation of communication disturbance observer for networked control systems with information losses

Networked control systems (NCSs) using the Internet will soon become widespread. In NCSs, time delays and information losses cause system performance degradation and destabilization. It is known that a communication disturbance observer (CDOB)-based compensator can estimate and suppress the effect of time delays on the system as a network disturbance. We applied a CDOB-based compensator to NCSs with not only time delays but also information losses and theoretically analyzed the information- loss compensation scheme. However, the performance of the CDOB-based compensator for only information losses in real NCSs has not been experimentally evaluated. This letter demonstrates an information-loss compensation scheme using a CDOB for NCSs. Experiments using a networked motion control system show that the CDOB-based compensator can estimate and suppress the effect of information losses on an NCS.