New improved delay-dependent H∞ filter design for uncertain neutral systems

The problem of a robust delay-dependent filter design for linear continuous-time neutral systems subject to uncertain mixed delays and time-invariant parameters is discussed. The uncertain parameters appear affinely in all system matrices and are assumed to belong to a given polytope. A general linear filter is proposed to guarantee that the induced L₂-norm of the filtering error system is less than a prescribed level for all allowed uncertainties. The proposed result is based on the selection of an alternative discretised parameter-dependent Lyapunov-Krasovskii functional and the introduction of slack variables which allows one to decouple the system matrices from the Lyapunov functional matrices. Numerical examples are performed to support the advantage of the proposed method.