Identification of Dynamically Positioned Ships
نویسندگان
چکیده
Todays model-based dynamic positioning (DP) systems require that the ship and thruster dynamics are known with some accuracy in order to use linear quadratic optimal control theory. However, it is diicult to identify the mathematical model of a dynamically positioned (DP) ship since the ship is not persistently excited under DP. In addition the ship parameter estimation problem is nonlinear and multivariable with only position and thruster state measurements available for parameter estimation. The process and measurement noise most also be modelled in order to avoid parameter drift due to environmental disturbances and sensor failure. This article discusses an oo-line parallel extended Kalman lter (EKF) algorithm utilizing two measurement series in parallel to estimate the parameters in the DP ship model. Full-scale experiments with a supply vessel are used to demonstrate the convergence and robustness of the proposed parameter estimator.
منابع مشابه
Comments on "Nonlinear output feedback control of dynamically positioned ships using vectorial observer backstepping"
The decomposition of nonlinear output feedback control into an observer and a state feedback control is an open problem. A solution for dynamic positioning of ships has been proposed in 1] and 2], where an observer-based back-stepping method is used. This note points out that the observer design in 1] and 2] does not cover unstable ship dynamics and suggests a remedy for an extended class of sh...
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