Variable Structure Observers for Nonlinear Models with Unbounded Noise and Measurement Uncertainties

This work extends the applicability of variable structure observers designed for nonlinear systems in two ways. First, it is proved that these observers using a boundary layer scheme can be applied to system models described by Ito differential equations resulting in almost sure and mean square exponential estimation error. Second, the use of variable structure observer is extended to nonlinear measurement models containing disturbance effects. Finally, two examples are given to illustrate the application of these generalizations.