Design And Research On Digital Model Library Of Marine Electric Propulsion System

Currently,the digital design technology of marine electric propulsion system is basic blank in domestic.This dissertation design and research the digital model library of marine electric propulsion system is based on the project of “oriented the simulation and research of integrated electric propulsion system”.The purpose of this study is to build hierarchical structure of digital model library and preliminary realize the function of establishing digital model.So this can lay the foundation for the ship digitized design platform with independent intellectual property rights.The main points of the dissertation are as follows:Firstly,the dissertation is based on the main functions and characteristics of digital model library,the overall scheme of digital model library,including virtual model library,formal library,standard library and database system,and we analyze the hierarchy between the libraries.Among the libraries,virtual model library is specially introduced.SQL Client mode is choosed to connect with the database and the fuzzy matching mode to query data;The function of the formal library and standard library are analyzed,and its organizational structure have been established.Secondly,After studying the specific function of digital model library,this software chooses the WPF(Windows Presentation Foundation),Blend and SQL Server as development environment.In addition,this dissertation briefly introduces the application of each software in this subject.Thirdly,the dissertation studies the multi-join query optimization problem(MJQO)for digital model library and sets up the mathematical model of MJQO problem.In order to solve the MJQO problem,this dissertation applies the ant colony algorithm(ACA)to the database query.It improves the traditional ACA and the local pheromone update rule and pseudo-random proportion are introduced to the ACA,then this dissertation builds a multi-join query optimization model based on ant colony system(ACS).MJQO was turn to be a similar TSP.Based on ant colony algorithm,the process and steps to solve the MJQO problem is given.Through the experimental analysis,in this dissertation,studying the influence of different parameters on the algorithm performance,and compared with the genetic algorithm and Greedy algorithm,it is proved that ant colony algorithm have good properties to deal with the problem of MJQO.Finally,software for digital model library of ship electric propulsion system is written.The development process of digital model library is mainly introduced.Its basic features include user management,fuzzy query,file management,remote access,operation,etc.This software establish a basic system framework,it can allow a 2D model to interact between different interfaces.Users can set up a connection into a model system of ship electric propulsion system by dragging,moving,scaling and rotating the models.Model system can intuitively present the connection between the models.Now,the software preliminarily realizes the development of digital model library.The standard library and formal library storage related content about the digital design,and these libraries provide query,modify,add,delete,and other basic function.So it is convenient for user to edit the information.