Specific-Time Unknown Input Observer for Lur’e System

This paper investigates the problem of specific-time state estimation for Lur’e systems with unknown inputs. By analyzing nonlinear Lur’e systems, sufficient conditions for the design of unknown input observers are provided. Then, a specific-time observer is designed, with convergence analysis illustrated. The main advantage of the designed observer can realize accurate estimation of Lur’e system in specific time. Finally, a simulation example of the third-order Chua’s circuit is conducted to verify the validity of the proposed specific-time unknown input observer.