Robust stability analysis of neutral systems under model transformation

Focuses on the delay-dependent robust stability of linear neutral delay systems. The systems under consideration are described by functional differential equations, with norm bounded time varying nonlinear uncertainties in the "state", in the delayed "state" and norm bounded time varying quasilinear uncertainties in the difference operator. Two unknown constant delays, in the delayed "state" and in the difference operator, lead to consider a more general delay-dependent robust stability problem. The analysis is performed via Lyapunov-Krasovskii functional approach. Sufficient conditions for robust stability are given in terms of the existence of positive definite solutions of MI or of LMIs. The proposed stability analysis extends some previous results on the subject.