Design And Implementation Of OPC UA And TSN For Real-Time Ethernet Networks

With the development of industry 4.0,industrial intelligent manufacturing and automation technologies have put forward higher requirements for intelligence,standardization and modularization.At present,the traditional Ethernet is mainly designed for the Internet and cannot meet the real-time demand of industrial motion control.The emergence of time sensitive network(TSN)is beneficial to further improve industrial real-time performance.In addition,industry 4.0 requires the use of a unified standard bus in the industrial field to achieve interconnection.However,many existing ethernet-based communication protocols in the market are promoted by different PLC suppliers,which cannot exchange data directly between them.OPC Unified Architecture(OPC UA),as a data exchange specification for industrial communication,can effectively solve the problem of access consistency and standardization of data communication.However,OPC UA lacks real-time guarantee in the industrial Ethernet environment,so it cannot meet the application scenario of high reliability and high real-time demand of industrial communication.In fully studied at home and abroad based on the study of the real-time industrial Ethernet,this paper puts forward the high real-time Ethernet oriented OPC UA and passes on collaborative design plan,improved the real-time performance of the operating system kernel,is proposed based on passes on packets to send and receive real-time TBS queue mechanism,and based on passes on collaborative design improved the publish-subscribe pattern of traditional OPC UA has the real-time guarantees.(1)For the industrial application scenarios of general operating system delay problems,improve the real-time performance of the kernel,the kernel process real-time scheduling using two-way linked list to select the highest priority thread to execute,the kernel is introduced into the counter support preemption,use soft interrupt threads real-time interrupt handling,transform the spin lock to support the priority inheritance the mutex,support different priority task preemption,using virtual memory lock form-feed efficiency aspects improve real-time operating system.Experimental results show that the real-time performance of the improved operating system has been greatly improved.(2)Based on the real-time communication capability of IEEE 802.1Qbv standard in TSN time-sensitive network,the real-time guarantee strategy of packet receiving and receiving is improved,the TBS queue mechanism is proposed,and the hardware clock synchronization and system clock synchronization of master and slave stations are realized in the data link layer by using PTP time synchronization protocol to ensure the real-time performance of data transmission.Experimental results show that the TBS queue mechanism has higher real-time performance than the default kernel flow control mechanism.(3)In the application layer using OPC UA application information model publish-subscribe mechanism,based on the above the improved data packets to send and receive real-time strategy,improve the traditional non real-time OPC UA publish-subscribe mechanism,adopting the tactics of "replace the copy",reuse of binary encoding and decoding network message generated of the agreement,the interrupt call all the functions in the process of reentrant.Finally,experimental results show that the OPC UA TSN network oriented to real-time collaborative design has a certain delay jitter change and low round trip delay.