Research On Dynamic Positioning Dynamic Capability Evaluation System Of Ocean Engineering Vessel

Dynamic positioning capability analysis is an important part of the dynamic positioning system.On the one hand,it can be used as a standard for evaluating the merits of the dynamic positioning system.On the other hand,it is also the basis of the dynamic positioning system design.It includes static analysis and dynamic analysis.The dissertation studies the dynamic positioning evaluation system,including the analysis of ship mathematical model,external environmental load calculation,controller design and dynamic capacity analysis method of dynamic positioning.A dynamic capability evaluation software of dynamic positioning was developed by using a mixed programming of Matlab and C++.Finally,the software was applied to engineering cases to evaluate the dynamic capabilities of multi-purpose tugboats.The main research contents of the paper are as follows:(1)The ship movement mathematical model and environmental load model were determined,and the wind load,wave load and flow load were calculated and simulated,which provided model support for dynamic capability assessment of dynamic positioning.(2)According to the characteristics of dynamic positioning control system,a PID controller is designed.According to the uncertainty of the ship's motion model and the randomness of external disturbances,the cloud model and PID control are combined to design a composite cloud model controller.For the problem that the parameters of the cloud model controller are difficult to set,the electromagnetic-like mechanism algorithm is introduced.However,there is a defect that falls into the local optimum in the later in the algorithm.Thus,a cloud model PID controller based on the immune electromagnetic-like mechanism algorithm is designed.Taking the multifunctional tug as an example,the control effects of the four controllers are verified by simulation.The results show that all controllers can achieve positioning,but the fourth controller has better control effects and positioning capabilities.(3)Study the dynamic positioning evaluation system,the overall structure and major functional modules of the dynamic evaluation system are designed,which mainly includes ship motion module,environmental load module,filter and state estimation module,controller module and thrust distribution module.Through the calculation and analysis of the limit wind speed and thruster utilization,dynamic assessment of the dynamicpositioning capability was realized.(4)Based on the above dynamic positioning dynamic capability analysis method,Visual Studio 2013 is used as a development tool to design the structure and function of the dynamic capability analysis software.C++ and MATLAB mixed programming are used to achieve the DynCap software running design.The DynCap software's dynamic capability assessment for multi-purpose tugs provides a certain reference for verifying the safety of the ship's positioning,and also provides a certain basis for the design of its dynamic positioning system.