New Improvement Approaches to H∞ Controller Designs Based on Fuzzy Observers for T-S Fuzzy Systems with Time-varying Delay

This paper provides an improved result over that in (X. Liu and Q. Zhang, Automatica, 2003) and (Y. Yuan. and W. Che, Control and Decision, 2005) for the problem of observer-based H_infin control for nonlinear systems with time-varying delay in Takagi-Sugeno (T-S) fuzzy model. It contributes in three aspects: (i) The present result is less conservative than that in (Y. Yuan. and W. Che, Control and Decision, 2005); (ii) The present strict LMI method is a single step approach which overcomes the drawback of a two-step approach in (Y. Yuan. and W. Che, Control and Decision, 2005); (iii) The matrix dimensions are largely reduced compared with the corresponding ones in (Y. Yuan. and W. Che, Control and Decision, 2005)