State observer design for Networked Control Systems with variable delay in both feedback and forward channels

This paper concerns with the problem of state observer design for discrete linear time-invariant systems where sensor measurements and control actions are transmitted via a communication network. Variable delay is considered in the Networked Control System (NCS) model to represent both of the data packet latency and dropout. The dynamics of observer is described in the switched systems' framework. Then, the issue of observer design is regarded as the stabilization problem of a switched system. Sufficient condition is derived to determine observer gain in terms of Bilinear Matrix Inequality (BMI). Numerical example is utilized to demonstrate the efficiency of this scheme.