A State Observer for Nonlinear Delay Systems with Delayed Output

This paper presents an asymptotic state observer for the class of nonlinear dynamic systems with time-delay both in the dynamic equation and in the output equa tion. In previous works state observers have been stud ied only for nonlinear systems with delay in the state equation and without delay in the output equation and for nonlinear system with only output delay. Su±cient conditions are given on the system and on the size of the delay that ensure exponential convergence of the observed state to the true one. For simplicity, only the case of systems with one input and one output is considered in this paper, although the approach used here can be applied also to multi-input/multi-output systems.