Study Of Automatic Tracking Control Strategy For Offshore Support Vessel

In the process of providing offshore support operations for the marine platforms,the offshore support vessel needed to rely on their power positioning system to stabilize near the offshore drilling platforms or other marine oil and gas facilities.As an indispensable part of the overseas operations environment,the training of the power and positioning operator of the offshore support vessel was costly and time-consuming.It needed the power and positioning simulation as an auxiliary exercise to cope with the increasing demands of the marine operations.The positioning system was widely used in the study,training and assessment of the sailors.It was also a platform for relevant scientific research and theory verification,and played an irreplaceable role in the development of new functions in the simulation test.The automatic tracking function of the dynamic positioning system could provide good operating conditions for the offshore support vessel.In this dissertation,the automatic tracking control strategy of the oil support ship was a research topic.In view of the special operation mode of the automatic tracking,the control strategy was improved to meet the requirements of the tracking operation,The automatic tracking control strategy was divided into path tracking control strategy and target tracking control strategy.On the basis of the man-machine interaction interface of the model of the crude oil supporting ship built by the research team earlier,the automatic tracking and control function of the offshore support vessel were studied.The specific research work was as follows:1.With the help of the positioning system,the automatic tracking function of the offshore support vessel were required,which laid a foundation for the development of the tracking function of the targets under water,the tracking function of the targets on the water and the tracking function of the path.In this dissertation,the problem of shaking and maintaining a safe distance of the traditional sliding mode control was considered,and an improved sliding mode control strategy was proposed.Considering the advantages and disadvantages of the traditional sliding mode and the backstepping sliding mode controller,the double functions were added to the smooth transition controller's output.Under the influence of the environment factors such as wind waves and currents,the advantages of the improved sliding mode controller proposed in this dissertation in the automatic tracking control were proved.2.Aiming at the problem that the automatic control strategy research of domestic offshore support vessel stays at the stage of the simulation experiment,a human-machine interface similar to the actual operation interface was designed.The simulation control strategy was converted from Simulink module to C++ program by using Matlab Coder tool of MATLAB and TLC file,and then encapsulated as the dynamic link library.This function library is called by using the simulator prototype built earlier by the subject team.Path tracking and target tracking functions in the high-level control strategy were integrated into the operation interface,and the result of the control theory was applied to the simulation prototype.3.According to the control strategy of the route tracking,the route was created according to the navigation does.A smooth path was created by the method of inserting the turning radius.Considering the great amount of heading information contained in the different trajectory points and the change of the direction change rate in the trajectory,and combining the change of the direction change rate in the trajectory and the design of the reduced dimension optimal function with the help of the particle swarm optimization,the problem of the direction change in the environment of wind and waves was proposed to be improved.In this way,the tracking process would be efficient and energy saving.4.In view of the influence of complex sea conditions on fixed-point rotation function,underwater target tracking function and surface target tracking function in the target tracking control strategy,the overall consideration of the factors such as the relative position of the offshore support vessel and the initial bow of the ship,the random moving trajectory of the target under the environment of wind waves and currents,the tracking strategy was respectively designed for different operation requirements and the changes of the external environment.Finally,based on the improved sliding mode control strategy,the simulation experiment is completed,and the UI interface is used to call the automatic tracking control strategy to verify the effectiveness of the target tracking control strategy.Finally,the conclusions and future work are given.