Research On The Profile Of CAD System In Transformation Of Existing Line

According to the plan of medium and long term development of Chinese railway, till2020, the mileage of the railway on operation will be120000km, of which the alteration andaddition of the existing railway line will approximatelybe19000km, added the new railwaybeing putted into operation, there will be a lot line overhaul work in a certain period. So it isquite important to research the profile optimization design method of existing line, andimprove the level of railway reconstruction.During the profile optimization design of railway reconstruction, it requires moreconsideration of the constraint limits in optimization algorithm due to the presence of a largenumber of bridges, tunnels, stations, and existing equipments. The applications of the linearprogramming method, the gradient projection method, the dynamic programming method,and the genetic algorithm are all based on the generating of initial profile, while the quality ofthe initial profile has great impact on the results of the optimization and can not take fullaccount of the constraint limits. How to find an intelligent global optimization algorithm isthe key to improve the level of profile optimization design in transformation of existing lines.Combined with the ant colony optimization and the features of profile optimizationdesign in transformation of existing lines, the papers design discrete profile optimizationmodel based on the ant colony optimization. And mainly complete the following aspects:(1) Analysis of the features of profile optimization design in transformation of existinglinesCombined with the survey methods of existing railway, make a detailed analysis aboutthe basic requirements of survey and design steps, data processing, and profile optimization.(2) Study the application of the ant colony optimization in profile optimization ofexisting linesIntroduce the ant colony optimization into the profile optimization of existing line, andtransform the continuous domain problems into the discrete large-scale combinatorialproblems in the profile optimization, establish the optimization model according to theconstraint limits condition in the profile optimization of existing line. Use the mileage andelevation of model gradient changeable point as the design variables, and use the ant colonyoptimization to find the optimal space position of the gradient changeable point in the gridpoints that satisfy the constraint limits.And it is verified by the engineering examples.(3) Design of the auxiliary CAD system ofprofile optimization in transformation ofexisting linesUse VB to re-develop AutoCAD, complete the profile of CAD system in transformationof existing lines to achieve the two functional modules: profile optimization and CAD drawings. In the profile optimizationmodule, use Excel as a data entry and output platform,different data stored in different worksheets, and use Excel as a data source to design andenlarge the drawing module.The papers use the ant colony optimization to complete the profile optimization design intransformation of existing lines, which well solve the problem of large amount of constraintlimits in profile optimization. The enlarging profile drawing module promote a good bridgingfunction between enlarging profile optimization and drawing, and provide a reference to theapplication of ant colonyoptimization in similar projects.