Joint State and Fault Estimation for Discrete-Time Networked Systems with Unknown Measurement Delays

This paper addresses the joint state and fault estimation problem for a class of discrete-time networked systems with unknown measurement delays. A novel augmented observer is developed to simultaneously estimate system states, fault signals and the perturbed term caused by measurement delays. For this purpose, an augmented descriptor system is first established by considering the faults and the perturbed term as auxiliary state vectors. Then, a modified state-space observer is constructed to estimate the extended state. Intensive stability analysis is carried out to obtain the sufficient condition for the existence of the desired estimator, and the corresponding optimal observer parameters can be co-designed by solving a convex optimization problem. Finally, a numerical example is exploited to illustrate the effectiveness of the proposed joint estimation scheme.