State estimation in quantized feedback control system

Recently, by development of communication techniques, control via communication is expected to take important part in networked control systems (NCSs) and so on. The main problem of the NCSs is that data are transmitted via a communication channel which has a constraint of capacity by converting a continuous signal into a discrete signal by using quantizer to compress the amount of information. Therefore, the discrete signal has a margin of error called quantization error. In the quantized feedback control systems, we use an observer to estimate a state if the state is not available, and use the estimated state in feedback control. In such cases, the system may be unstable and degraded the performance since the states estimation is not performed properly due to the quantization error. Hence, an state estimator must be designed with taking into account the effect of quantization error. In this paper, we propose a designing state estimator method in discrete-time systems with the quantized output. The effectiveness of the proposed method is illustrated with experiments.