Research On Intelligent Planning Of Assembly Sequence Driven By Prior Knowledge And CAD Model Data

With the advancement of Industry 4.0,the development of the manufacturing industry has shown digital and intelligent features.Assembly is one of the most important,time-consuming and costly steps in the product manufacturing process.Intelligent assembly sequence planning has become An important technology for automation and enhancing market competitiveness.At present,the structure and function of products are becoming more and more complex.Carrying out computer-aided assembly sequence planning centered on model data acquisition,assembly knowledge expression and application is an important way to improve the comprehensive competitiveness of China's manufacturing industry.Based on digital twins and knowledge model guiding ideology,this paper proposes an assembly sequence intelligent planning method based on a priori knowledge and CAD model data,research and design CAD model data acquisition,assembly domain ontology knowledge modeling,assembly sequence intelligent planning method,Key technologies such as assembly process simulation.The main work of this article includes:(1)Based on the secondary development technology of CATIA Automation,an improved recursive traversal algorithm is proposed,which uses object-oriented design ideas to develop model information automatic extraction software;based on the tree structure first traversal idea,depth first,from root to branch,Progressive layer by layer,deep mining of assembly and constraint information of multi-layer nested complex 3D model can effectively improve the utilization rate of 3D model information and lay a data foundation for the establishment of assembly knowledge model.(2)Based on Eclipse IDE and Jena API,introduce a priori knowledge into the assembly domain ontology framework system,develop assembly domain ontology automatic modeling software;read Excel model data,expand ontology model information in the form of examples and attributes,and give full play to the ontology The advantages of the model in knowledge expression and description logic realize the automatic construction of the ontology knowledge model in the assembly domain;effectively improve the modeling efficiency and accuracy,and lay the knowledge foundation for the intelligent planning of assembly sequences.(3)Based on Eclipse IDE,develop assembly sequence intelligent planning software;introduce a priori knowledge into data optimization and rule reasoning,identify assembly structure features,and divide typical and atypical structures;typical structures directly give assembly sequences,for atypical structures,Establish a fuzzy set membership function system of parts,and obtain weight sequences;based on the specific constraint relationship between each part,based on the weight sequence for the second reasoning,and finally get the complete assembly sequence.(4)Based on CATIA Automation API,develop assembly sequence simulation software in digital space;access CATIA DMU Fitting function module,call trajectory generation and visualization work instructions,automatically create assembly trajectories of each part,and integrate into complete assembly simulation animation.Finally,the integration of four key technologies to build a priori knowledge and CAD model data driven assembly sequence intelligent planning system,through the example of worm reducer and gear reducer to verify the feasibility of this method.