# Some references about Modelling and Identification

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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).

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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
)

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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).

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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

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