Research On Computer Aided Aero Blade Redesign And Process Intelligence Planning Technology

Aeronautical blades are the most core part of aeroengine.Due to their harsh working environment,it is particularly difficult to manufacture for its extremely high requirements of manufacturing precision and surface quality.Redesign of blade and process planning are significant foundations to ensure the quality and efficiency of blade manufacturing,in which enterprises are confronted with problems such as low precision of reconstructed profile,poor smoothness,high repeatability of work and long period of process documentation currently.Such problems have seriously affected the efficiency and quality of blade manufacturing,resulting in failing to meet the requirements of high-performance design and batch manufacturing of aerospace blades.In view of this,the key technologies such as reconstruction of blade body model and parametric design of blade root and crown are deeply studied,and a blade process reasoning method based on rule-based and case-based reasoning is proposed,which lays a technical foundation for improving the efficiency and quality of blade structure design and process planning.The main research contents of this paper are as follows:The blade surface reconstruction is studied based on the back calculation theory of Bspline curve and surface interpolation.The chord height difference method is used to preprocess the blade shape value point data to remove noise points.The optimal control vertices are solved,and the steps of fairing curve reconstruction from shape value points are completed by minimizing the approximation error and the global curvature value,together with the fairing Bspline curve reconstruction algorithm aiming at making the global curvature change more uniform.The back calculation process of B-spline surface interpolation is simplified,and the fairing curve reconstruction algorithm is extended to the surface fairing reconstruction.The blade surface reconstruction method is proposed,and the surface reconstruction is verified method according to the surface illumination reflection ray quality and surface reconstruction error.The design method of blade root and blade crown is studied,based on the idea of parametric design.The expression corresponding to each size is established through the "expression" function,and the parametric part template associated with the expression is created to complete the creation of the parametric template.Common blade root and crown parametric design modules are developed,and different human-computer interaction interfaces for different types of blade root and crown are designed.Input parameter inspection mechanism of their own are established to make the design process more intuitive and less error-prone.The intelligent programming of blade process is completed through the hybrid reasoning technology of case-based reasoning and rule-based reasoning.The knowledge in process planning is described in detail,and the key information of blade process is extracted.Meanwhile,based on the meaning of each attribute in the key information,the relationship organization structure of process knowledge is constructed,and the case base and rule base are created to realize the storage and management of process knowledge.Based on the nearest neighbor index method of weighted evaluation of primary factors,a calculation method of global similarity between process instances is proposed to realize accurate and efficient retrieval of process instances.The process instance modification and storage strategy is established,and the preparation and storage of the process completed by reusing and modifying the process instance information with high similarity.Based on the blade redesign method and process intelligent programming technology,the redesign system and process programming system are developed.All commonly used parametric design interfaces of blade root and blade crown are integrated through UG secondary development technology,and the function of directly reconstructing blade surface from profile value point data is realized through blade body reconstruction module.The information transmission mechanism from redesign system to process planning system is established,and the development of process reasoning module based on server database is completed.Additionally,the data management system of personnel information and knowledge base is developed to facilitate the review and maintenance of data by managers.This paper improves the efficiency and quality of blade structure design and process planning by the curve and surface smoothing algorithm based on B-spline,the parameterized modeling method of blade root and blade crown,the blade process planning method based on hybrid reasoning and the corresponding interactive platform development,reduces the work intensity of staff,and has certain significance to improve the competitiveness of enterprises.