Sliding-mode observer for uncertain systems. I Linear systems case

A sliding mode observer for linear uncertain systems is proposed. The advantage of the proposed observer is that it works under much less conservative conditions than Wallcot et al.´s observer (1987). In addition, we address the issue of estimating a function of the state as well as unknown inputs or structural uncertainties. Further, the idea is extended to a general class of nonlinear uncertain systems. Numerical examples are used to illustrate the validity of the proposed observer design strategy