Semi-globally convergent observer for single-output-bounded-state systems subject to time-delay

A semi-globally convergent nonlinear observer is proposed for bounded-state nonlinear systems subject to state-delay nonlinearities. The proposed design can be seen as an extension of the results given in. In the present paper the observer gain is derived from a time-varying-parameter-dependent Riccati equation with arbitrary weighting matrices. Illustrative numerical example is given to demonstrate the simplicity and the efficacy of the new design.