Robust Observer Design for Takagi‐Sugeno Fuzzy Systems with Mixed Neutral and Discrete Delays and Unknown Inputs

A robust observer design is proposed for Takagi‐Sugeno fuzzy neutral models with unknown inputs. The model consists of a mixed neutral and discrete delay, and the disturbances are imposed on both state and output signals. Delay‐dependent sufficient conditions for the design of an unknown input T‐S observer with time delays are given in terms of linear matrix inequalities. Some relaxations are introduced by using intermediate variables. A numerical example is given to illustrate the effectiveness of the given results.