Research On Data-Centric Digital Twin Conceptual Model Construction Method

With the development of a new round of information technology revolution,the manufacturing industry will take digital transformation as the next generation development direction.By establishing a digital copy of the physical world,digital twin not only enables people to better perceive the real-time scene in the three-dimensional space,but also conduct a deep analysis of the data generated in the physical world,so as to provide a reference for people to make decisions on the operation of the physical world.Therefore,digital twin has attracted more and more attention from experts in various fields.However,the implementation of digital twin applications faces two problems.On the one hand,digital twin frameworks have not been unified and modeling paradigms have not been fully studied.On the other hand,digital twin involves knowledge of multiple fields,disciplines and scales.Software engineers lack business knowledge background,and few professionals in the field have the ability to develop software systems.As a result,data can not be used well,and the application of digital twin system encounters challenges.In order to deal with the above challenges,this paper regards data as the first class citizen of digital twin,and studies the data-centric digital twin conceptual model construction method.Through the analysis of digital twin system,this paper determines the five characteristics of digital twin concept modeling.By comparing the life cycle of data,the expression of attributes and operations of data and the degree of integration with software architecture,the paper discusses whether digital twinning modeling should be object-oriented or data-oriented,or other oriented,and solves the problem of the conceptual modeling paradigm of digital twinning.This paper puts forward a general digital twin framework,and discusses how the data-centered digital twin conceptual model connects the OPC UA data acquisition protocol and digital twin system in this framework by studying the technologies involved in this framework.OPC UA information model is based on XML,database in digital twin system and object-oriented programming language can use XML format files as the medium of data conversion.This lays a theoretical foundation for the data-centric digital twin conceptual model and their information exchange.In order to transform the main data files involved in the digital twin system,this paper also proposes the XML-based data markup language named DML for the data-centric digital twin conceptual model.DML describes the attributes and types of data,the event mechanism,and the input and output of services,which provides guidance and specification for the development of the whole digital twin system at the conceptual level.Because DML is based on XML,it can give full play to the advantages of XML semantic expression and data exchange.This paper presents the process and algorithm of data exchange based on the Java Script language running in the browser.The paper develops the data-centric digital twin conceptual model construction system named DTModeling.Finally,a storage digital twin system was developed for a dairy factory.Theory and practice prove that the data-centered digital twin conceptual model construction method can fully express the data semantics,and is suitable for the exchange of data and files in the digital twin system,which solves the two challenges faced by digital twin applications.