Identificação de sistemas usando modelos Hammerstein e Wiener utilizando método do relé.

Abstract

In this work is used a method of the relay feedback under conditions of non-linearity and static disturbance for identification of Hammerstein and Wiener-type nonlinear process. The relay feedback approach used guarantees a symmetrical output relay when a cyclic steady state is obtained, regardless of static disturbance, while the original method shows an asymmetric output relay in such conditions. For Wiener-type process is proposed an exitation signal that incorporates the advantages of the modified method relay feedback and in addition, characteristics of the obtained low frequency excitation from the use of a rectangular pulse. for identification of Hummerstein-type process, initially the method of modified relay is applied and so the data of frequency response of the linear dynamic subsystem are obtained. Then, a triangular signal is used to identify the static nonlinear function. The principal difficulty in the identification of Hammerstein and Wiener process is the unavailability of intermediate signal. Therefore, procedures for obtaining intermediate signal are presented from the relay feedback under conditions of non-linearity. The identification techniques presented throughout in this work are evaluated simulated and experimental cases to verify the performance of each