ABSTRACT

By taking the influence of the roll motion and propeller revolution into account, a method based on support vector machines is proposed for identifying the hydrodynamic derivatives and the coefficients of hull-propeller-rudder interaction in the MMG model for ship manoeuvring motion in 4 degrees of freedom. 10°/10°, 20°/20° zigzag tests and 35° turning circle manoeuvre are simulated for a container ship by using the hydrodynamic derivatives and interaction coefficients obtained from the captive model tests. Part of the simulation data of 20°/20° zigzag test is used to identify the hydrodynamic derivatives and interaction coefficients, and the identification results are compared with those of captive model tests to verify the identification method. Then 10°/10°, 20°/20° zigzag tests and 35° turning circle manoeuvre are predicted with the identified hydrodynamic derivatives and interaction coefficients. The predicted results are compared with those of simulation tests to demonstrate the good predictive ability and generalization performance of the proposed identification method.

INTRODUCTION

For a long time, investigation of ship manoeuvring motion with the influences of roll motion being taken into account has been one of research hotspots in the field of ship hydrodynamics. Reliable roll prediction and control are vital to ship operations such as deployment and landing of aircrafts aboard the ship deck. However, ship roll motion is a complex nonlinear phenomenon with time-varying dynamics and strong uncertainty (Fossen, 2011). Son and Nomoto investigated the sway-yaw-roll coupling motion of a container ship on the basis of captive model tests, and a 4 degrees of freedom (4-DOF) motion equation (surge-sway-yaw-roll) was established in MMG model(Son and Nomoto, 1982). Fossen simulated the 4-DOF ship maneuvering motion using the hydrodynamic coefficients from Son and Nomoto's tests (Fossen, 1994). Pérez and Blanke (2002) presented a nonlinear Abkowitz model for a container ship based on the experimental results of the 4-DOF roll planar motion mechanism facility at the Danish Maritime Institute. Hui and Zhang (2013) established a response model for ship roll by analog modelling method. Yoshimura (2011) introduced the rudder to yaw response equation from the simple linear mathematical model, and clarified the principal structure regarding to the effect of the roll motion on ship manoeuvrability.

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