Recursive Identification of Systems with Noninvertible Output Nonlinearities

Article type: Research Article

Authors: Vörös, Jozef

Affiliations: Faculty of Electrical Engineering and Information Technology, Slovak Technical University, Ilkovicova 3, 812 19 Bratislava, Slovakia , e-mail: jvoros@ elf.stuba.sk

Abstract: The paper deals with the recursive identification of dynamic systems having noninvertible output characteristics, which can be represented by the Wiener model. A special form of the model is considered where the linear dynamic block is given by its transfer function and the nonlinear static block is characterized by such a description of the piecewise-linear characteristic, which is appropriate for noninvertible nonlinearities. The proposed algorithm is a direct application of the known recursive least squares method extended with the estimation of internal variables and enables the on-line estimation of both the linear block parameters and the parameters of some noninvertible nonlinearities and their changes. The feasibility of the proposed method is illustrated on examples of time-varying systems.

Keywords: nonlinear systems, recursive identification, Wiener model, noninvertible characteristics

Journal: Informatica, vol. 21, no. 1, pp. 139-148, 2010