Design And Implementation Of CAD System For Ship Cable Lying

With the development of ship electrification, there are more and more electrical equipment and cable in a modern ship. The traditional design mode cannot guarantee the path which developer chosen is optimal or near optimal, the result of cable lying design and related reports are changed frequently. Therefore, the development of a CAD system for the ship cable lying has immense meaning for improving design efficiency and controlling the ship costs.The overall scheme of the CAD System for ship cable lying design is designed by using the customization of AutoCAD technology by using AutoCAD.NET API, combined with SQLite databases and MVC software design pattern. And the system is divided into three modules, Channel Generating, Cable Lying and Report Output, which connected by AutoCAD and SQLite. On the base of this overall scheme, the data structure of cable channel is adjacency multi list. The using inheritance, and gradually establish the object model which suit algorithm and meet the cable lying design. For cable routing, after the raw data of cable channels is processed by processing algorithm and all the cable channels are shown on the AutoCAD by calling the AutoCAD.NET API, the system uses the A*algorithm to quickly obtain optimal or near-optimal cable route scheme. The weight number setting of side is determined by the complexity of manufacturing and the length of side. And the heuristic function of A*algorithm is designed to be the sum of the Manhattan distance and the current point to goal and the length of unit vector cross-product between a selected vector and the current point to goal vector. Then all the tables which contain background information and results of cable lying in the database are normalized to a3rd Normal Form. That would provide the conditions for the rapid modification the result of cable lying. Finally, using the open library EPPlus based on the OpenXML standard, the system can read the template of cable books and write the result to a new document based the template.The prototype of ship cable laying CAD system has been completed, achieved the basic functions, and the cable route scheme and cable books meet the requirements. The preliminary test show that the overall scheme is reasonable, technical route is correct. Under further perfection, the system could be used in the practical work.