A New Coordinate System and the Equations Describing Manoeuvring Motion of a Ship in Waves

Hamamoto, Masami; Kim, Yoon-Soo

doi:10.2534/jjasnaoe1968.1993.209

Cited by 53 publications

(19 citation statements)

References 1 publication

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“…Substitute equation (21) into equation (22) and then derivative of f obj with respect to f s . Let @f obj =@f s ¼ 0, the optimal expression of the driving force of the non-generalized driving branch is given as…”

Section: Dynamics Modeling Of the Mechanismmentioning

confidence: 99%

Coupling 3-PSR/PSU 5-axis compensation mechanism for stabilized platform and its analysis

Liu

Zhao

Luo³

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part C:

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This article presents a coupling 3-PSR/PSU parallel mechanism for ship-based stabilized platform based on the coupling characteristics of the ship motions. With coupling characteristics, the goal of 3-axis drives and 5-axis compensation of the moving platform is achieved. From the screw theory, degrees-of-freedom and coupling kinematic characteristics of the mechanism are analyzed. A method for equivalent transformation of motion parameters is proposed. This presents a mapping relationship between the independent degrees-of-freedom and the coupling degrees-of-freedom. The investigations are further extended to the coupling dynamics characteristics of the mechanism. In particular, the effects produced by the coupling force/torque to the system are analyzed. Hence, taking minimum system driving force as the optimization goal, the coupling dynamic equation of the parallel mechanism is established. The numerical example reveals that this coupling parallel mechanism can be applied to the multi-axis compensation of ship-based stabilized platform. The study also enriches the application area of lower-mobility parallel mechanism.

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Section: Dynamics Modeling Of the Mechanismmentioning

confidence: 99%

Coupling 3-PSR/PSU 5-axis compensation mechanism for stabilized platform and its analysis

Liu

Zhao

Luo³

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…A body-fixed system G-x 0 y 0 z 0 has its origin at the center of gravity of the ship. A horizontal body G-xyz coordinate system [46] also has its origin at the center of gravity and does not rotate around the x-axis and y-axis.…”

Section: Configuration Of the Onr Flare Topside Vesselmentioning

confidence: 99%

Broaching probability for a ship in irregular stern-quartering waves: theoretical prediction and experimental validation

et al. 2016

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To avoid stability failure due to the broaching associated with surf riding, the International Maritime Organization (IMO) has begun to develop multilayered intact stability criteria. A theoretical model using deterministic ship dynamics and stochastic wave theory is a candidate for the highest layer of this scheme. To complete the project, experimental validation of the theoretical method for estimating broaching probability in irregular waves is indispensable. We therefore conducted free-running model experiments using a typical twin-propeller and twin-rudder ship in irregular waves. A simulation model of coupled surge-sway-yaw-roll motion was simultaneously refined. The broaching probability calculated by the theoretical method was within the 95 % confidence interval of that obtained from the experimental data. This could be an example of experimental validation of the theoretical method for estimating the broaching probability when a ship meets a wave.

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“…Finally a "horizontal body axes" is expressed as O-xyz. The origin of "horizontal body axes" is the center of gravity as the same as the "body fixed axes" but this coordinate system is not allowed to rotate around the x and y axes 14) . Coordinate transformation relationships are obtained as Eqs.…”

Section: Gz (M)mentioning

confidence: 99%

An Improvement of Broaching Prediction with a Nonlinear 6 Degrees of Freedom Model

et al. 2011

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SummaryThis paper reports on the improvements of a simulation model for ship motions in following and quartering waves. The authors use a wave-piercing tumblehome vessel as a subject ship. The existing 4-DoF (degrees of freedom) model shows some limitation in its capability for predicting broaching of this vessel. In a free-running model experiment for the vessel, we observed rudder and propeller emersion from the water leading to broaching. This rudder and propeller emersions can significantly reduce steering performance. To express these rudder and propeller emersions, we should take account of not only roll but also pitch and heave. Therefore the authors develop a 6-DoF model. With the heave and pitch motion, we can calculate the local draft variation for calculating wave exiting forces and moments. Roll restoring variations are one of the important factors to estimate roll motions. Therefore we theoretically estimate restoring variations in wave then we found the tendency of variation dramatically changes due to the roll angle. Submergence of superstructure can be important for that variation. We also consider the variation of maneuvering coefficients and rudder forces in waves which are relevant to broaching. To estimate these variations, we conduct PMM tests, straight-line tests and rudder angle tests in waves using a scale model of subject ship. With some of these improvements, we obtain better agreements with experimental results than existing 4-DoF model.

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A New Coordinate System and the Equations Describing Manoeuvring Motion of a Ship in Waves

Cited by 53 publications

References 1 publication

Coupling 3-PSR/PSU 5-axis compensation mechanism for stabilized platform and its analysis

Coupling 3-PSR/PSU 5-axis compensation mechanism for stabilized platform and its analysis

Broaching probability for a ship in irregular stern-quartering waves: theoretical prediction and experimental validation

An Improvement of Broaching Prediction with a Nonlinear 6 Degrees of Freedom Model

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