Method and device for averting and damping rolling of a ship

摘要

This invention relates to a method and a device for averting and damping rolling of an engine-driven marine vessel with propeller propulsion. The proposed method recognizes the fact that the speed controller of a ship responds to heel angle variations by propeller speed adjustments. A speed controller is reading such propeller moment change as speed variations to be corrected. By the recurrence of this process, the result is amplifying small rolling effects to a critical rolling. Further elements contribute to this process, such as the propeller side effects ship's hull contact with the sea, waves or winds. However, by suppressing the interaction between heel angle variations and the speed controller, the rolling of a ship can be effectively reduced and averted. The proposed method, by suppressing the cause of the critical rolling, reduces rolling, fuel consumption and maintenance of the ship's propulsion engines.

主权项

1. A method for averting and damping rolling of a marine ship with propeller propulsion, wherein
the current heel angle of the ship is sensed and a sequence of said sensed heel angles is used to compute values that characterize the behavior of ship's rolling comprising rolling amplitude, rolling period and trends of the rolling amplitude and rolling period, a model is used to characterize the behavior of ship's rolling as a critical interaction between the ship's dynamics and the ship's engine/propeller speed controller, said critical interaction increases or maintains the rolling of the ship, signals that are related to the ship's rolling, including their derivatives of first and second order, and parameters that effect ship's rolling, characterize together the ship's dynamics and are used in the said model, and a selection of a proper control algorithm is done, based on said ship's rolling model and on said rolling trend data to avert and damp said critical interaction between the ship's dynamics and the engine/propeller speed controller by modifying the function of the engine/propeller speed regulator such that said critical interaction is counteracted.