| The design process of hydraulic excavator is a knowledge-intensive process,which requires a large amount of relevant knowledge to support in all stages of design,and these required knowledge types are complicated,diverse and interrelated.However,the current excavator design work still relies heavily on the designers’ own design experience,existing design literature and other means for design calculation,which is not only unfavorable to the reuse of knowledge but also has the problems of repeated calculation,large workload and low efficiency.At the same time,how to effectively manage this knowledge is the main research content to improve the innovation competitiveness of enterprises.In order to solve the above problems,this paper proposes the classification,organization,expression and storage method of knowledge related to hydraulic excavator based on object-oriented and graph database according to the content of knowledge related to the design process of hydraulic excavator and its role in the design process.The expression templates of various types of knowledge are designed,and the knowledge screening,semantic retrieval and parameter retrieval are realized by using the relevant technology of natural language processing and combining with the content of the knowledge graph.The design process of hydraulic excavator working device is analyzed and the functions such as detailed calculation of relevant structure dimensions and envelope drawing are realized through programming,and NSGA-Ⅱ multi-objective optimization algorithm and gray correlation analysis are introduced to optimize the calculation results in a relevant way.Based on this work,a thematic knowledge base system based on the graph database Neo4 j with B/S architecture is constructed by using the technical means of.NET platform to realize the reuse of knowledge and related calculation functions.The main research contributions of this paper are as follows:(1)The main contents of the thematic knowledge required for the design of hydraulic excavators were studied,and the design process of hydraulic excavators and the role,classification and characteristics of thematic knowledge were analyzed.The method of knowledge mapping is selected to organize the thematic knowledge and the method of graph database Neo4 j is used to store the thematic knowledge.(2)Using the object-oriented approach based on the object-oriented approach,the corresponding expression templates are constructed,and the various types of knowledge are expressed by combining the various types of knowledge association characteristics of the knowledge graph.Using relevant techniques such as Chinese word separation,dependent syntactic analysis,and AC automata,the user’s retrieval intention is determined,and the corresponding Cypher statements are generated by matching the specified templates to realize knowledge retrieval.(3)The design process related to the hydraulic excavator working device is analyzed,and the calculation function of the knowledge base is constructed according to the corresponding process in the knowledge base,so as to integrate the calculation function with the knowledge retrieval function.Using components such as Raphael.js,the relevant envelope diagram is realized.The multi-objective optimization algorithm NSGA-Ⅱ and the gray correlation analysis method are introduced to optimize the calculation results,thus reducing the workload of repeated calculations.(4)By analyzing the requirements of users,we designed and built the whole system structure of the thematic knowledge base,using Visual Studio as the development tool,Sqlserver and Neo4 j as the database,and MVC as the program development framework,we designed and developed and deployed a graph database based thematic knowledge base system for hydraulic excavators under B/S architecture.The usability of the knowledge base system was tested by using relevant software testing methods,and the effectiveness of the system was verified by using relevant application examples. |
