Some references about Modelling and Identification

Identification of multivariable models of fast ferries

J. Aranda, J. M. de la Cruz, J. M. Díaz

European Journal of Control. Vol.10, n. 2. May 2004. Pp: 187-198. 

This work presents the formal approach for identifying continuous transfer functions of the vertical dynamics of a high-speed ship as a non-linear optimisation problem with linear restrictions. The proposed solution is described with a hybrid optimisation method (genetic algorithm + classic non-linear optimisation algorithm with restrictions).

An analysis of models identification methods for high speed crafts

Joaquín Aranda Almansa, Rocío Muñoz Mansilla, Sebastián Dormido Canto, José Manuel Díaz Martínez, Sebastián Dormido Bencomo

Journal of Maritime Research, Vol. II.No. 1, pp. 51-67, 2005

Two different approaches of the system identification method have been proposed in order to estimate models for heave, pitch and roll dynamics of a high speed craft. Both of them resolve the identification subject as an optimization problem to fit the best model. The first approach uses genetic algorithms and nonlinear least squares with constraints methods applied in the frequency domain. The second one suggests a new parameterization which facilitates obtaining high quality starting values and avoids non-quadratic functions in the cost function. At last it is shown an example in which the two approximations are applied and compared. (more )

Interval modelling of high speed craft for robust control.

J. Aranda, JM de la Cruz, JM Diaz, P. Ruiperez.

2Int_con_mar_tec_inn_res(cadiz2000).

Modelling of a high speed craft by a non-linear least squares method with constraints

J. Aranda, J.M. de la Cruz, J.M. Díaz, B. de Andrés, P. Ruipérez, S. Esteban

MCMC 2000

A non linear least squares method with constraints have been tried. However, the extra complexity associated with non-linear systems, with constrains and no initial information of model structure, means that exhaustive search is not always feasible. In these cases genetic identification strategy can be used to obtain initial values. On the other hand, a trend in the area of system identification is to try to model the system uncertainties to fit the available analysis and design tools of robust control. The method described is applied to obtain the interval model of the vertical dynamic of a high speed craft for different speed, and comparative results obtained with the mathematical model and with a scaled model in a towing tank are showed