On the interval estimation for nonlinear singular system

This paper investigates the interval observer design problem for a class of nonlinear singular systems with uncertainties in the state and in the output. Although the asymptotic estimation of the state for this class of systems may be not possible, it has been shown that, under suitable assumptions, an interval observer can be designed to provide the upper and the lower estimations of the real state. Moreover, this technique can be applied to unobservable nonlinear singular systems to obtain the interval estimation. The proposed result can be easily extended to deal with the nonlinear singular systems with parameter uncertainty as well.