Generalized conditions for H∞ disturbance attenuation of fuzzy time-delay systems

In this paper, we consider the H_∞ disturbance attenuation of Takagi-Sugeno fuzzy retarded and neutral type time-delay systems. A descriptor system approach is taken to analyze and synthesize fuzzy time-delay systems. We first make an H_∞ disturbance attenuation analysis and obtain sufficient conditions for an H_∞-norm to be less than a prescribed number. Sufficient conditions we obtain are given in terms of linear matrix inequalities (LMIs) and generalization of delay-dependent conditions for fuzzy time-delay systems. This generalization reduces the conservative of both delay-independent and delay-dependent conditions in the literature. Next, we consider a state feedback controller design. Based on the H_∞ disturbance attenuation analysis, we give delay-dependent sufficient conditions for the closed-loop system to achieve the H_∞ disturbance attenuation. Finally, a simple example is given to illustrate the theory.