Sampled-data observer design for a class of nonlinear systems with delayed measurements

This paper addresses the problem of observer design for a class of upper triangular nonlinear systems with sampled and delayed measurements. A sampled-data observer is presented by using the sampled and delayed measured outputs. The observer has continuous variables and discrete variables. The network-induced delay, which may be larger or less than the sampling period, is also taken into consideration in the observer design. Therefore, the observer is hybrid in nature. It is proven that the observer errors are globally and exponentially convergent. The sampled-data observer design method is also extended to nonlinear systems with lower triangular form. Finally, two illustrative examples are presented to show the effectiveness of the proposed design methods.