A framework for the observer design for networked control systems

This paper provides a general framework for the observer design for networked control systems (NCS) affected by disturbances, via an emulation-like approach. The proposed model formulation allows us to consider various static and dynamic time-scheduling protocols, in-network processing implementations and encompasses sampled-data systems as a particular case. Provided that the continuous-time observer is robust to measurement errors (in an appropriate sense) we derive bounds on the maximum allowable transmission interval (MATI) that ensure the convergence of observation errors under network-induced communication constraints. The stability analysis is trajectory-based and utilizes small-gain arguments. It has to be emphasized that this paper also furnishes new tools for the observer design for sampled-data systems. Various observers can be combined and used within our approach to obtain estimators for NCS.