Research On Key Technologies Of Knowledge Integration For CNC Machine Tool Digital Design Process

Manufacturing informatization is an important measure to promote the development of manufacturing industry and also a technology guarantee to realize the intelligent manufacturing.The digitalization design and manufacture is a main part of the Manufacturing informatization.Personnel,process,product and knowledge interact with each other in the process of the digital design and manufacturing of products.The designer in the process of design and development needs a lot of knowledge.Through the innovation activities of the designers,a lot of new knowledge is generated and will be applied to the next development process.Therefore,how to integrate these four factors effectively is the key to improve the quality and efficiency of product design.However,currently in the process of the design of Computer numerical control(CNC)machine tools,there are lots of problems.The design efficiency is low,the design process depends on manual control,it lacks digital analysis and the design resource and design knowledge is too scattered to use.Therefore,in view of the problems above,this paper expands the research,based on 'process' and 'knowledge'-the two core factors which support the digital integrated design of CNC machine tools.Many key technologies of the digital integrated design of CNC machine tools are studied systematically,such as the system architecture,the design knowledge representation,the integration technology of digitized integration design knowledge and process,the method of design knowledge retrieval and design knowledge push.It provides the integration of personnel,process and knowledge during the digitized integration design with technical support,in order to improve the design level and design efficiency of CNC machine tools.The main research content includes the following aspects:(1)The research on the method of the knowledge integration for CNC machine tool digital design process and the architecture of the CNC machine tools digital design knowledge integration system(MTDDKIS).Firstly,the current design process of CNC machine tools and the existing problems in this process are elaborated.A new method named the knowledge integration for CNC machine tool digital design process is proposed which is combined with 'process' and 'knowledge' to support the digital integrated design of CNC machine tools.This method is to realize the digitization of knowledge,process,software tools and the integration of knowledge,process,and software tools.On this basis,an architecture of the CNC machine tools digital design knowledge integration system is built and concentrated with knowledge.The contents of each layer of the system and their interrelations are explained.In the end,the key technologies to realize the digital integrated design system of CNC machine tools,concentrated by knowledge,are analyzed.This research provides a general framework for this study.(2)The research on the digital design knowledge model of CNC machine tools.Based on explaining the definition,classification and characteristic of knowledge,we analyzed the knowledge of the digital integrated design of CNC machine tools in view of the knowledge applied and then put forward the model of knowledge representation based on ontology which laid a foundation for the knowledge reusing.(3)The research on the integrated method of the knowledge and process of the digital integrated design of CNC machine tools.In order to integrate all the factors effectively in the business process,such as knowledge,product,personnel etc.,based on the detailed analysis of the knowledge and process of the digital integrated design of CNC machine tools,an integration method of design knowledge and business process is proposed.This integration model called PPKO(Product,Process,Knowledge,Organization)includes product model,process model,knowledge model and organization model,which means that the personnel engaged in the business process,use knowledge to complete business activities and create new knowledge at the same time.Based on this integration model,the interrelation between business process and knowledge is discussed and the pattern of knowledge reuse is proposed,including the 'pull' pattern and the 'push' pattern.The 'pull' pattern presents the knowledge resource retrieval,and the Multi-dimensional knowledge resource browsing.The 'pull' pattern presents the knowledge recommendation.(4)The research on ontology based retrieval of knowledge resources for the CNC machine tools digital design process.In view of the problems of knowledge acquisition in the CNC machine tool development process and distinctive engineering features of the digital integrated design knowledge retrieval,we proposed two retrieval patents,including the ontology based semantic retrieval and the multi-dimensional dynamic browsing.They are different from the general information retrieval because they take the product,the design process,and multiple characteristics of the knowledge resources into consideration.The personalized ontology-based semantic retrieval is oriented to the engineering and the product.By dealing with the user's knowledge requirement,it uses the semantic expansion strategies and semantic similarity calculation method,according to the user's preferences,accurately provides the results to the user.Experimental results show that the proposed method can improve the precision and the recall of knowledge retrieval.The multi-dimensional dynamic browsing shows the knowledge to the users with different views,and uses the topic map to help the users to understand knowledge well.(5)The research on the knowledge recommendation based on the 'PPKO'.In order to effectively utilize the existing knowledge during the business process execution and avoid the information overload,a knowledge recommendation method is proposed based on 'PPKO'model.Firstly,based on established the integration model of knowledge,product,organization and processes,two recommendation modes focused on process and user are proposed,and the framework of knowledge recommendation is established.The knowledge recommendation based on process is a kind of situational awareness technology for the business process.It is designed to be aware the designer's current business-related information and predict the designer's knowledge preferences during the execution of the CNC machine tools development.Semantic similarity matching and historical information matching are two recommendation strategies.The knowledge recommendation based on organization has two ways,considering designer's preferences and similar designers respectively.One way is to acquire knowledge according to the designer's preferences.The other way is to find knowledge from his similar designers.The practice shows that the two recommendation modes could meet the different users' needs.(6)Based on the research of key technologies above,as the engineering practice of the above research results,the MTDDKIS is designed and developed independently.The function modules of MTDDKIS,the development and running environment are briefly introduced.Taking the development process of the concrete CNC machine tool(VDL600E produced by Dalian Machine Tool Group Corporation)as an example,MTDDKIS is validated.The practice shows that the MTDDKIS can effectively control the digital design process of CNC machine tools,effectively manage the knowledge in business processes,and it provides the knowledge retrieval,knowledge multi-dimensional browsing and knowledge recommendation and other knowledge service functions to the designer in a personalized way.It supports the designers to obtain the knowledge resources quickly and conveniently,helps them carry out innovation activities to improve the design quality and efficiency significantly.