Research On CNC Equipment Interconnection Based On OPC UA

The upsurge of new information technology brings new opportunities for the development of intelligent manufacturing,and at the same time it causes the rapid expansion of production process information in discrete manufacturing workshops,so it is difficult to integrate information with the characteristics of heterogeneity,real-time and diversity of forms.The effective integration of information between different network layers in manufacturing workshop is the basis of intelligent manufacturing,and the key is to realize the information sharing and CNC equipment interconnection.OPC UA is one of the key enabling technologies of CNC equipment interconnection at present,and many manufacturers propose OPC UA communication scheme for their own equipment and private data acquisition protocol.However,due to lacking of standard CNC equipment information model specification in OPC UA,the equipment models constructed by different manufacturers are not uniform,it is difficult to truly realize semantic interoperability between various equipment.Therefore,this thesis proposes a solution of CNC equipment interconnection,which includes data acquisition protocol integration,information modeling and development of model instantiation.The main work of this thesis is as follows.(1)Establishing the architecture of CNC equipment interconnection based on OPC UA.This thesis analyzes the existing problems of CNC equipment interconnection,and it determines the main requirements of interconnection based on the production status of discrete manufacturing workshop.Then,based on the national standard draft of “CNC equipment interconnection and interoperation”,the universal scheme of CNC equipment interconnection based on OPC UA is established,and its physical architecture and functional architecture is analyzed.The functional architecture of the scheme includes equipment module,plug-in library module,OPC UA server,data analysis,storage and transmission module and application module.These function modules realize data transmission and function union through the interface,which realizes the information integration of equipment,systems,equipment and systems.(2)Research on information modeling and model mapping of CNC equipment.Using object-oriented modeling method based on meta model to build meta model of CNC equipment,which included the core elements of devices,components,attribute sets,attributes,attribute elements,etc.On the basis of the meta model,complete,standard and extensible information model of CNC machine tool and CNC robot is established,which provide a standard for the digital modeling of a large number of various machine tools and robots in the factory.In order to realize the standardization of model mapping for OPC UA,this thesis analyzes the mapping relationship between CNC equipment source model and OPC UA model,and this thesis proposes the structure mapping method and syntax mapping method from CNC equipment meta model to OPC UA address space.(3)Research on the key enabling technologies of CNC equipment interconnection.The information model implementation technology based on XML is proposed.The research includes the data acquisition of Siemens system based on OPC protocol,FANUC system based on FOCAS function library,GSK system based on Modbus TCP protocol and KND system based on Restful architecture,and this thesis integrates the data acquisition protocol based on plug-in technology.This thesis introduces the OPC UA application architecture and the development method of OPC UA server based on SDK,and gives the implementation mechanism of OPC UA subscription service.(4)The realization and verification of CNC equipment interconnection.Developing and implementing CNC equipment information model(XML document)and OPC UA information model(XML document),data acquisition protocol plug-in,OPC UA server software,etc.Then the interconnection test platform is built to test and verify by means of universal opcua client accessing the server node information.Finally,it is applied in the "digital workshop of machine tool gear machining".