Networked continuous-time filtering for quadratically inner-bounded time-delay systems with multirate sampling

Abstract

This paper addresses the networked H∞ filtering problem for time-delay systems with quadratically inner-bounded nonlinearities, where the different output sub-vectors of the systems are sampled respectively by sensor groups with different sampling periods (i.e., multirate sampling or MRS). The multirate sampled data are transmitted to a filter through multiple communication channels with network-induced packet dropouts and time-varying transmission delays. Considering MRS’s asynchronous behavior, we propose a matching mechanism to synchronize the successfully transmitted sampled data of the nonlinear system and the sampled data of a filter. Based on the matched sampled data, two types of new continuous-time filters are presented to estimate the objective signal of the nonlinear system. In view of the fact that the lifting technique may fail to model the nonlinear system, the resultant filtering error systems are modeled as continuous-time nonlinear systems with several sawtooth delays. By the Lyapunov-Krasovskii functional approach, some sufficient conditions are obtained to ensure that the filtering error systems are stable with a prescribed H∞ performance level, and the design methods of the two filters are given. Finally, a numerical example shows the effectiveness of our proposed methods.