A New Robust Identification Algorithm for Hammerstein-Like System Using Identification Error Structure

Abstract

A new robust identification algorithm is introduced in this study for a Hammerstein-like system based on identification error information. With the help of the half-substitution idea, the identification model is converted into a compact model where the coupling parameters are avoided. To reduce the effect of noise signals, a filter gain is proposed to obtain helpful system data. Then, on the basis of the filtered variables and developed forcing variables, the identification error information is extracted from the helpful system data. By using the identification error data, a new parameter estimation adaptive law that differs from the classic prediction error method is derived. Therefore, a new identification scheme framework is proposed and the weakness of the prediction error method is improved. Simulations and a real-life plant are presented to test the validity and practicality of the presented identification approach. The results of parameter estimation and estimation error qualitatively demonstrated the advantages of the proposed algorithm. The computational complexity and performance evaluation indicators results of the developed algorithm quantitatively indicated that the proposed algorithm produces higher estimation performance compared with the other algorithms.

Keywords

• Hammerstein-like system
• memory nonlinearity
• parameter estimation
• robust algorithm
• identification error