Identification of nonlinear system using extreme learning machine based Hammerstein model

• ELM-Hammerstein model is proposed for identifying nonlinear system.
• The structure of ELM-Hammerstein model is determined using Lipschitz quotient.
• A generalized ELM algorithm is proposed to estimate the parameters of ELM-Hammerstein model.

In this paper, a new method for nonlinear system identification via extreme learning machine neural network based Hammerstein model (ELM-Hammerstein) is proposed. The ELM-Hammerstein model consists of static ELM neural network followed by a linear dynamic subsystem. The identification of nonlinear system is achieved by determining the structure of ELM-Hammerstein model and estimating its parameters. Lipschitz quotient criterion is adopted to determine the structure of ELM-Hammerstein model from input–output data. A generalized ELM algorithm is proposed to estimate the parameters of ELM-Hammerstein model, where the parameters of linear dynamic part and the output weights of ELM neural network are estimated simultaneously. The proposed method can obtain more accurate identification results with less computation complexity. Three simulation examples demonstrate its effectiveness.