Simulation Research On Modeling And Control Of Ship Roll Motion

Affected by environmental interferences such as wind and wave and many other factors, excessive sway is produced when ship sailing on the sea,goods and equipment. Therefore, people are always looking for ways to reduce the sway of the ship. And among the variety ship swaying motions, ship rolling motion is the factor that affect navigation safety of the ship the most. To reduce ship rolling motion is one of the important issues in the field of ship motion control. In this paper, Fin Stabilized control system is the object of study, rolling motion modeling for the ship and anti-rolling control has been research in depth.To study the ship’s rolling motion, it is needed to study the impact the wave affect to the ship, wave is the main reason of the ship rolling motion, to establish an ideal and practical wave disturbance mathematical model is the basic condition of the research of ship roll motion. To study ship carrying Roll Stabilization control, ship rolling motion should be research in depth and establish control model of Roll Stabilization. When the ship roll motion angle is small, the theory of linear rolling motion could be applied on ship rolling motion. But when the angle of the ship rolling motion is large (eg greater than8degrees), many nonlinear factors came out. Roll linear model could not reflect the characteristics of the ship rolling motions properly. Based on the above reasons, this paper is based on wave spectrum analysis theory, build Long crested wave of random sea waves disturbance model, of different sea conditions of wave height and wave inclination modeled and digital simulation; analysis of ship rolling wave motions, establish of a ship rolling mathematical model; based on this, fin stabilizer control system is the main object of this paper, using the traditional PID method to control the ship rolling motion, good effect is been achieved on specific ship parameters and sea condition. Taking into consideration the complexity of the ship rolling motion, nonlinear, time-varying sea conditions and uncertainty, the RBF neural network supervisory control of PID controller are been put in use, the simulation results show that the control system can overcome the shortcomings of poor adaptability of the traditional PID controller, has the ability of fault tolerance and strong nonlinearity.