This paper presents the solution of output feedback $H∞$ control problem for linear neutral systems with unknown constant multiple state delays in delay independent case, without any restrictions on plant matrices $D12$ and $D21.$ First, some sufficient conditions for the solution of this problem are obtained in closed-loop system matrices in both linear matrix inequality (LMI) and algebraic Riccati inequality (ARI) forms, by standard Lyapunov-Krazovskii functional in delay independent multi-delay case. Because of the complexity of the solution of the compensator from these inequalities, equivalent sufficient conditions are derived for designing output feedback controller which stabilizes the closed-loop neutral system under consideration and guarantees an $H∞$-norm bound constraint on the disturbance attenuation. These conditions are of the form two ARIs and, for simplicity in computation equivalent LMIs are given. Finally, output feedback $H∞$ controller design is achieved and the results are illustrated in some numerical examples.

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