Research On Path Following And Control Method Of HYSY 201

For some tasks in ocean engineering,especially under moderate or severe sea conditions,dynamic positioning vessels are often required as construction vessels or auxiliary vessels.There are high requirements for vessel path following ability and position maintenance accuracy in tasks.At the same time,in order to adapt to different tasks,it is necessary to match different thrust allocation methods to meet the requirements for different operation objectives during the operation process.Therefore,it is necessary to study the generation,guidance,and path following motion control of desired paths according to the path requirements of marine engineering tasks,to study the matching thrust allocation methods,and to develop an integrated dynamic positioning simulation control system.It has certain practical reference value and theoretical significance for practical projects.Firstly,taking the "HYSY 201" vessel as the research object,a mathematical model of the vessel was established based on the research methods of general surface vessel dynamics and3-degree of freedom kinematics models.The accuracy and reliability of the established model were verified through simulation.Secondly,according to the requirements of a certain engineering task,a path generation algorithm based on waypoint table is designed,which can display the predicted trajectory in the interface before simulation as an aid for actual operations.According to the principle of LOS guidance method,a guidance algorithm for arc paths is proposed to determine the position of the vessel’s guidance point on the arc path.A switching strategy for the linear and curved composite path guidance method is proposed to ensure the continuity of vessel motion during path switching.A multi target controller for the vessel is designed,with matching path tracking function.The position,attitude,and velocity of the vessel are controlled simultaneously using inner and outer loop control.Thirdly,a thrust allocation method matching the path tracking control function is designed.Firstly,a mathematical model of the propulsion system is established based on the layout characteristics of the vessel’s propellers,and a mathematical model of the resultant force and torque generated by each propeller to the control point is established.According to the principle of propeller-propeller interference,a thrust exclusion zone is set for each propeller.Considering the principle of heading priority,an improved direct allocation method is proposed,which can better utilize the coordinate position advantages of the three propellers no.1,2,and 7,and is suitable for working conditions where vessels have a need for yaw torque.Through comparative analysis and simulation,it is verified that the method has rapid response to yaw torque and low power consumption.Finally,the dynamic positioning simulator software for the vessel was developed through the Qt Creator platform,which integrates the path generation,guidance,path tracking control,and improved thrust allocation methods studied previously.The corresponding functions of each module are established,and corresponding input and output structures are created based on the input and output information of each module,which are used as the input and output parameter types of each function.Each function is used as the internal system of the software.The data-acquisition function and information-display function are designed as the external system of the software.According to the characteristics of dynamic positioning systems,different operating modes have been developed.Finally,a comprehensive simulation analysis of path following motion control for the "HYSY 201" vessel is performed in this software.