EPA无线工业控制系统的任务调度算法

Task scheduling algorithm of wireless industrial control system based on EPA

针对基于EPA标准的工业控制系统底层使用无线通信技术时,传统的实时调度机制不适应无线工业应用的特点,很难达到原有的效果等问题。以解决无线工业控制系统通信任务的超时现象为目的,提出了适合无线EPA标准的任务调度算法。利用启发式机制搜索合理的通信任务预留时间,并根据预留时间进行功能任务和通信任务的联合调度。最后,分析了基于该方法的一个应用实例,该调度方法有效地延长了通信任务的截止时间,进而补偿了无线技术在工业恶劣环境中出现的信道传输质量极不稳定带来的实时性较差等负面影响。

The traditional real-time scheduling mechanism is unfit for characteristic of wireless industrial application. When the physical layer of industrial control system based on EPA makes use of wireless technology the performance of traditional scheduling mechanism faces serious degradations. For the purpose of solution overtime problem about communications task of wireless industrial control system, the scheduling algorithm according to wireless EPA profile is proposed in this paper. The reasonable remained time is found by heuristic mechanism. Function block task and communication task are scheduled together based on the remained time. Finally, an application based on the algorithm is analyzed. The proposed scheduling algorithm extended the deadline for the communications task, and compensated some adverse effect that instability of transmission quality resulted in declining on the real-time in execrable industrial environment.