一种面向OPC UA消息通信的多优先级动态调度算法的设计与实现

Design and Implementation of a Multi-priority Dynamic Scheduling Algorithm for OPC UA Message Communication

在工业4.0时代,OPC统一架构(OPC UA)在各种工业系统中的应用为数据的交互提供了基础技术支撑,具有关键性作用.工业数据在传输时需要考虑到差异化服务的问题,但目前现有的OPC UA通信模式无法满足上述要求,基于这个问题,本文研究了OPC UA消息发布机制,并提出了一种面向OPC UA消息通信的多优先级动态调度算法.在该算法中,不同时实性的消息利用最早时限优先主动队列管理算法进行调度和区分,通信上下文环境消息通过多级反馈队列调度算法进行调度,这两种方式共同用于OPC UA消息调度以改善服务质量.经实验证明,在差异化优先级消息的调度和处理上,利用该算法改进的OPC UA通信组件表现良好,并且在OPC UA服务器高负载的情况下,高实时性消息的响应的优先性和次数明显高于其他类型消息,其接收量达58.6%,服务质量相比改进前有了较大程度的提升.该算法在OPC UA通信栈中的应用可以满足OPC UA服务器在工业生产中的需求.

In the era of industry 4.0,OPC UA provides basic technical support for various data interactions and plays a key role in the field of industrial control.Aiming at the existing problem that the current OPC UA communication mode cannot solve the problem of industrial data real-time transmission,this paper studies the message publishing mechanism in OPC UA communication stack and proposes a multi-priority dynamic scheduling algorithm for OPC UA message communication.In order to improve the service quality of the server,the Multi-Layer Feedback Queue is used to process the messages in building communication context,besides,different real-time data messages are distinguished and scheduled by the Earliest Deadline First with Multi Priority Algorithm.It is proved that the algorithm raised in this paper play a role of scheduling messages with different real-time performance in OPC UA server.Under the condition of high network load,the receiving amount of high real-time messages is 58.6%,which is greater than the amount of the rest kind of messages,and the quality of service of the OPC UA communication components is also greatly improved.The application of this algorithm in OPC UA stack can meet the industrial production needs of OPC UA servers.