Research And Development Of CMM Inspeciton Path Planning System For Blades Based On MBD

In view of the problems existing in the traditional inspection mode of product parts based on the combination of two-dimensional drawing and three-dimensional digital model,such as insufficient automation level,the easy loss of inspection information in the process of transmission and the long inspection preparation cycle,this dissertation introduces introduces model-based definition(MBD)technology into blade CMM inspection planning,and CMM inspection path planning system for blades based on MBD is developed on the basis of the UG platform.The main work content and results of this dissertation are as follows:(1)The overall scheme design of the system.The technical requirements of CMM inspection path planning system for blades based on MBD are analyzed,and the overall framework and workflow of the system are proposed.Based on UG secondary development technology,MBD model building module,MBD model feature recognition and PMI information extraction module,inspection information management module,inspection path planning module and inspection program output module are designed in detail.(2)Establish the MBD model of the blade.Based on the research and analysis of MBD model organization structure,the standard specifications for establishing MBD model are determined.Combined with the turbine blade structure and its classification,the MBD model of the blade is established.(3)MBD model feature recognition and PMI information extraction.The extended attribute adjacency graph is used to express the geometric and topological relationship of MBD model,and the typical blade structure features are stored in the predefined feature library in the form of extended attribute adjacency matrix.The algorithm of matching attribute adjacency matrix is proposed to effectively realize the rapid and accurate identification of blade structure features.(4)The planning of inspection path.According to the sampling strategy of blade root and crown structure,this dissertation discusses the planning method of the number and distribution position of measuring points on complex polygonal surface and cylindrical surface.For the steam passage,the order of “surface-curve-point set” is adopted to decompose and sample it.The ant colony algorithm is used to optimize the inspection sequence of the measuring points,and the outer circle obstacle avoidance and the expanded bounding box obstacle avoidance are used collision avoidance method is combined with Vericut for path simulation,and finally the non-interference optimal path is output into a DMIS format program to guide the CMM for inspection.(5)The verification of the system.Taking a certain company’s blade inspection planning as an example,the whole process of each module operation of CMM inspection path planning system for blades based on MBD was demonstrated and explained in detail,and the feasibility and accuracy of the system were verified by experiments.This prototype system provides a new way to ensure the uniqueness of the data transmission process and realize the paperless blade inspection mode,which can effectively improve the work efficiency of CMM inspection personnel in the process of blade inspection planning,and help enterprises accelerate the realization of the digitization of blade production and inspection projects.It has a great significance for enterprises to improve their competitiveness.