Observer Design for a Class of Systems with Mismatched Uncertainties via Variable Structure Control

A variable structure observer (VSO) design problem solved by VSC (variable structure control) theory for system together with mis-matched uncertainty is studied in this paper. In the sliding mode, if developed systems are with mis-matched uncertainties, then invariance condition cannot be satisfied. Hence, we endeavor to design a new VSO structure. Under this VSO, if matching condition is unsatisfied, then estimation error trajectories will be bounded uniformly, and these estimation error trajectories will asymptotically approach to zero if they satisfied matching condition. Finally, a set of simulation results for a helpful example is shown to illustrate the validity of this developed VSO way.