Reliable H∞ filter design for a class of continuous-time nonlinear systems with time-varying delay

This paper is concerned with the reliable H_infin filtering problem against sensor failures for a class of continuous time systems with simultaneous sector-bounded nonlinearities and varying time delay. The resulting design is such that the filtering error system is asymptotically stable and meets the prescribed H_infin norm constraint in the nominal case as well as in the sensor failure case. A sufficient condition, which depend not only on the upper and lower bound of delay but also on the upper bound of delay derivative, for the existence of such a filter is obtained by using appropriate Lyapunov functional and linear matrix inequality (LMI) technique. What´s worth mentioning is that the information about the upper bound of delay derivative is taken into consideration even if this upper bound is not smaller than 1. A numerical example is provided to demonstrate the effectiveness of the proposed designs.