Nonlinear Observers by A Backstepping Approach

Abstract

A backstepping-like design method for reduced-order nonlinear observers is proposed. The basic idea of this method is as follows. At first an appropriate function of state variables to be estimated is constructed. Then the next function of state variables to be estimated is derived by designing the former nonlinear function observer. Finally the procedure terminates, resulting a partial differential equation to be solved. If the yielded differential equation is solvable, then the observer can be calculated. The connection between observers with linear error dynamics and this method is discussed.