Ship Dynamic Positioning Control With Dangerous Working Area

Due to the shortage of ground resources,people have turned energy exploration and development to the rich treasure house of the ocean.Therefore,the 21st century is called the era of the ocean.Under such a background,mankind has explored and exploited marine energy at sea,etc.Operations are becoming more and more frequent,but the ocean is also a very dangerous area for human beings.For example,dangerous objects such as mines left over from the war have not been effectively eliminated,which has brought huge hidden dangers to the lives and property of people at sea.When exploring and removing dangerous objects,if the traditional anchoring method is used in positioning control,the length of the anchor chain used in the system will increase when the water depth gradually increases,and its strength will increase correspondingly in order to resist environmental interference.As a result,the cost becomes higher;it will become more difficult to operate when anchoring,making the offshore operation more complicated,and greatly limiting the positioning ability of the ship,which can not meet the requirements for positioning in deep sea areas.Therefore,in the face of such offshore operations,Dynamic Positioning(DP)ships are more often used to solve various problems brought about by the mooring system.Because dynamic positioning ships have excellent maneuverability,good flexibility,and are not Features limited by ocean depth.Therefore,when exploring and eliminating dangerous targets,a dynamic positioning ship is more used,so the research on the positioning control of a dynamic positioning ship with a dangerous working area is of great significance.Because the positioning point is at the boundary of the circular dangerous working area,the path planning from the starting position to the positioning point is designed in this article to prevent the ship from entering the dangerous area during the positioning operation.In order to reduce the time to reach the positioning point,this article divides the area so that The dynamic positioning ship can track the path at high speed or low speed respectively.Considering the full / underdrive characteristics of the dynamic positioning ship at low / high speed,the corresponding path tracking controller is designed in this paper to achieve a good tracking effect.The energy carried is limited.In order to reduce the consumption of energy and the discharge of pollutants,an optimal environmental orientation positioning controller is designed.Mainly completed the following aspects of research:Firstly,the task of the project is analyzed,and the control target is given to highlight the purpose of the research.At the same time,a mathematical model is established for the motion of the dynamic positioning ship on the horizontal plane,and its correctness is verified by direct navigation and turning test.Secondly,by using the path planning method to design the path to avoid the dangerous work area to reach the target anchor point,based on the previous task description,an environmental model is established,and different measures are used to plan the path on both sides of the proposed switching circle to obtain a fast and fast A safe path to the target anchor point.Outside the switching circle,because the dangerous area has a small impact on the ship’s movement,the tangent segment of the circular dangerous area border is designed to reach the switching point on the switching circle.After reaching the switching circle,the discrete ant colony algorithm is used to change the distance from the switching point to The path between the target positioning points is planned,and finally a safe path that meets the control target is obtained.Then,based on the previously designed safety path,the dynamic positioning boat can move to the switching circle at high speed and then to the target positioning point at low speed,and the dynamic positioning boat will exhibit full / underdrive control characteristics at low / high speed,so A terminal sliding film controller based on a virtual guidance algorithm and a disturbance observer is designed at low speed,and a controller based on BLF and sliding mode under CB guidance algorithm is designed at high speed.In order to smooth the control force during low / high-speed switching,a switching control function is designed.Finally,simulation experiments verify that the designed algorithms have good path following effects.Finally,arc smoothing was performed on the path at the angle between the line segments in the path planning.In order to enable the power positioning boat to provide as little thrust as possible during the final positioning,that is,only the longitudinal thrust is used to resist the environmental combined force,an environment-based The update function to the optimal controller and catenary point is verified by stability proof and simulation test.Finally,simulation experiments were performed on the positioning control of the non-environmentoptimized and environmentally-optimized dynamic positioning vessels,and the results show that the tasks can be completed well.