Research On Thrust Allocation Of Dynamic Positioning Ship With Cycloidal Proreller

With the increasing development of marine technology in China,marine dynamic positioning(Dynamic Positioning DP)system is more and more dependent on the high control precision,reliability and adaptability is also put forward higher requirements,the need to control the precision can reach higher in any situation under the design requirements.In order to steer the ship more safely and efficiently,in the shallow water area of control has become an important measure to ensure safety of navigation,harbor an indispensable therefore particularly important to study the control performance is in the harbor tug.In this paper,a kind of ship with good handling performance in foreign countries,but has not been widely used in China's ports,that is,with a cycloidal propeller ship,and its motion characteristics of the study.On the basis of summing up the domestic and foreign public information,the author has drawn up a set of more precise and complete equations of motion of the ship with the advance of the MMG model.Firstly,the kinematics and dynamics model of three degrees of freedom and the disturbance model of wind,wave and current are established.Dynamic positioning system also needs control system,but the control system is not the focus of this paper,so the traditional PID controller is designed.After the mathematical model of the ship is established,the simulation experiment is carried out,and the results show that the ship model can reflect the ship motion under normal conditions.Secondly,the current ordinary propeller due to physical constraints,the excessive torque on the shaft damage,and the inversion efficiency is very low,and the cycloidal propeller because the blade perpendicular to the horizontal plane,its vertical axis rotation,avoids the damage of mechanical steering and steering speed limit,but because the very structure of cycloidal propeller the complex,technical requirements are relatively high,so it has not been widely used,so the research has important significanceAfter studying the principle of the cycloid propeller,the most important part of the normal operation of the ship is to distribute the control commands issued by the control system to each thruster.In this paper,the thrust allocation problem is studied,and the objective function of thrust allocation is established according to the constraint conditions.Its essence is nonlinear to find the optimal solution.There are two methods for solving the optimization problems,such as sequential quadratic programming method,pseudo inverse algorithm,particle swarm optimization algorithm,and so on.In this paper,the problem of solving the problem is solved by the two order programming.Finally,the simulation of thrust distribution in MATLAB is carried out.The results show that the feasibility and applicability of the two order programming algorithm for the thrust distribution of the cycloid propeller is presented.