Abstract: The problem of robust H∞ observer design for a class of Lur’e control systems with uncertain timedelay was studied. When the system state cannot be directly accepted， in the light of Lyapunov stability theory， the sufficient conditions for the existence of the state observer and observerbased robust controllers for Lur’e systems were obtained. What’s more， the corresponding state observer and observerbased robust controllers by constructing an augmented system were also given. The parameters of state observer and observerbased controllers could be obtained by solving two LMIs. Finally， a numerical example was provided to demonstrate the validity of the proposed design approach.

Key words: Lur’e control system, observer, uncertainty, robust controller, linear matrix inequality(LMI)