Design And Implementation Of Communication Component Of Intelligent Production Line Based On OPC UA

With the development of economy and the introduction of ‘industry 4.0',the traditional production line which is characterized by less variety and more production is facing transformation and upgrading.It is of great significance for the research on the intelligent production line.The development of intelligent manufacturing industry in China started late,and the degree of informatization and automation of intelligent production line is not high.There are problems such as difficulties in data collection at the bottom level and data interaction between different information systems.The realization of efficient and highly compatible data flow has become a major technical difficulty to be solved in the implementation of China's intelligent production line.Aiming at the problems of data acquisition difficulty of the underlying equipment in the intelligent production line,equipment's inability to carry out data sharing and unified management,and data interaction difficulty among information systems,this thesis proposes a communication scheme of intelligent production line based on the small testing production line built by the project as the experimental platform.OPC Unified Architecture is used to configure the underlying devices of the intelligent production line into the address space and update the device information in real time.At the same time,the data access service interface is opened for the upper layer,so as to achieve the compatibility and interworking between the underlying devices of the intelligent production line and the system of the upper layer based on OPC UA.Main contributions and innovations of this thesis are as follows:Firstly,the architecture of intelligent production line communication component based on OPC UA is built.To meet the communication needs of intelligent production line,the communication component integrates the device information acquisition plugin,OPC UA server,intelligent production line information model and database,and provides data interaction service as the interface between intelligent production line sensing layer and application layer.Through the communication components built,the devices in the sensing layer are constructed into an interconnected network structure,and the data transmission between the application layer and the perception layer is carried out based on OPC UA.The communication and data services of communication components are designed and realized.According to the modeling rules of OPC UA,the information modeling of the underlying equipment of the intelligent production line is carried out to provide the service foundation.A secure connection based on OPC UA security model is established to transfer data between secure information channels and sessions.According to the demand of intelligent production line data application,address space management module,read/write module,historical data read module,subscription and monitoring module are designed and implemented.The network construction and testing in the laboratory verify that the communication component can provide stable information interaction.Finally,a service quality optimization method for intelligent production line based on service classification is proposed.Aiming at the problem that the basic communication functions cannot meet the differentiated services in the real-time transmission of different industrial data,this thesis studies the communication mode of OPC UA message,and proposes a method of service quality optimization.Multi-stage feedback queue scheduling algorithm is used to process the communication context messages,and the earliest deadline first with multi-priority active queue management algorithm is used to manage and schedule different real-time messages,so as to improve the QoS of communication components.The experimental results show that this optimization method have a good regulating effect on the scheduling of messages with different priorities.Under high load,the receiving amount of high-real-time messages accounts for 58.6%.The service quality of communication components has been improved.