Ship Fin/rudder Roll Reduction Control Strategy Research

When ships sail on the sea, shipping accidents occurred frequently due to bad weather. Hull damage and economic loss happen because of roll motion. Intensely roll motion causes not only the huge economic loss, but also serious personal injury. Therefore, ship roll reduction control is necessary. The traditional ways for ship roll reduction control are stabilizer and rudder roll reduction. And they all have limitations. As is known, control action on the rudder will produce roll motion and stabilizer will also cause yaw motion. So fin rudder joint roll reduction control is a new type of roll reduction based on fin stabilizer and rudder roll reduction.The Hoo fin rudder joint controller is designed for the ship motion model. For the course-keeping control, based on the traditional PID autopilot, Kalman filter is used to limit wind and wave disturbances during the sail. So ship roll motion can be reduced and meanwhile the heading can be corrected.First, the movement of six degrees of freedom in the hull and inertial coordinate system is introduced. And the translational motion of the hull and rotation motion equations are derived. During the voyage, fluid forces of ship rudder and fin are analyzed to establish the kinetic equation.Second, for physical nature of wind and wave disturbances, the wind speed change spectral density function, the calculation method of interference force and torque are introduced. Then the two commonly used wind and waves spectral density formulas are showed and spectral density is used to generate lasted value. This method is used to help simulation research.Finally, through the controller design for the fin rudder joint control and Matlab simulation results for different sea level. The conclusion can be summarized from simulation curve that the control performance of fin rudder joint controller on roll reduction and course-keeping is perfect.