Discrete-time nonlinear observer design using functional equations

The present research work proposes a new approach to the discrete-time nonl inear observer design problem. Based on the early ideas that influenced the development of the linear Luenberger observer, the proposed approach devel ops a nonlinear analogue. The formulation of the discrete-time nonlinear ob server design problem is realized via a system of first-order linear nonhom ogeneous functional equations, and a rather general set of necessary and su fficient conditions for solvability is derived using results from functiona l equations theory. The solution to the above system of functional equation s can be proven to be locally analytic and this enables the development of a series solution method, that is easily programmable with the aid of a sym bolic software package. (C) 2001 Elsevier Science B.V. All rights reserved.