Observer Design for Generalized Quasi‐One‐Sided Lipschitz Nonlinear Neutral Systems With Multiple Delays

In this paper, the generalized quasi‐one‐sided Lipschitz (GQOSL) condition is initially proposed to address the design issue of state observers for certain nonlinear neutral systems with multiple delays. Subject to GQOSL constraint, corresponding sufficient criteria are worked out to ensure that the full‐order observer possesses asymptotic stability, and some sufficient criteria are developed to confirm the existence for reduced‐order observers pertaining to nonlinear neutral systems. Corresponding results for the single‐delay case are also presented. The lower conservatism of the GQOSL condition compared with the Lipschitz condition in the design of state observers for the above systems are verified through theoretical analysis and two numerical examples. Meanwhile, under the GQOSL condition, the asymptotic stability of observers for such systems is guaranteed by the presented sufficient conditions, even in the case where is undetectable.