Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2011.567.572JamaaliJ.MohammadiA.KeyvaaniH.32011113This study provides a novel modelling and identification approach to nonlinear systems. The model structure is based on modal series model of nonlinear systems. Modal series has been used for solving nonlinear differential equations. It provides an approximate solution for a nonlinear differential equation. Based on modal series, the paper proposed a model structure for nonlinear system identification. The proposed model structure introduces a linear subsystem and several Hammerstein subsystems for the main nonlinear system. Therefore, identification problem of a nonlinear system reduces to identification of a linear subsystem and several Hammerstein subsystems. Each Hammerstein subsystem contains a linear block and a nonlinear block. All Linear blocks of proposed model structure are the same and the structure of nonlinear block of each Hammerstein subsystem is distinct. The proposed model structure provides accessibility to different signals which may be used in the identification process of each block. Since modal series provides an approximate solution, in order to identify a more accurate model for the nonlinear system, one may use more calculation and more time to reach the satisfactory model. In order to identify the proposed model, an algorithm based on linear subspace identification methods and Hammerstein system identification has been proposed. Simulations are used to evaluate the results of what argued in this study.]]>Abdollahi, A.,2002Al-Duwaish, H. and M. Nazmul Karim,1997Bendat, J.S.,1990Emerson, R., M. Korenberg and M. Citron,1992Eskinat, E., S.H. Johnson and W.L. Luyben, 1991Gomez, J.C. and E. Baeyens,2000Haber, R. and H. Unbehauen,1990Haddad, W.M. and V. Chellaboina,2001Kalafatis, A., L. Wang and W. Cluett,1997Leonessa, A. and D.P. Luo,2001Shanechi, H.M., N. Pariz and E. Vaahedi,2003Pariz, N., H.M. Shanechi and E. Vaahedi,2003Ralston, J.C., A.M. Zoubir and B. Boashash,1997Sjoberg, J., Q. Zhang, L. Ljung, A. Benveniste and B. Delyon et al.,1995Van Overschee, P. and B. de Moor,1996Van Pelt, T.H. and D.S. Bernstein,2000Michel, V. and D. Westwick,1996Huebner, W.P., G.M. Saidel and R.J. Leigh,1990Zi-Qiang, L.,1993