FF现场总线系统调度问题的研究

FF现场总线系统(FCS)为典型的分布式实时系统，分布在不同设备（包括总线） 的功能块和通讯任务相互作用完成复杂的控制方案，除了实时性要求，还要考虑执行顺序和 资源约束，调度问题为一NP 完全问题．本文分析了FF控制系统的特点，提出了类比于作业 车间调度问题（JSSP）的调度模型，针对特殊的模型，设计相应的编码和解码规则以及性能 指标，用遗传算法在满足上述约束下构建调度表，实现无抖动调度，最后分析了该方法下系 统的可调度条件．

STUDY OF FF FIELDBUS CONTROL SYSTEM SCHEDULING PROBLEM

FF fieldbus control system(FCS) is a kind of typical distributing real time system, the interaction of function blocks and communication tasks which distribute on different device and bus implements complicated control scheme.In addition to constraint of time, constraint of sequence and resource is considered. Scheduling problem is NP complete problem. According to characteristics of FF system, this paper holds scheduling model is similar to job shop scheduling problem. After designing rules of code /decode and fitness function, scheduling table which is satisfied with all constraints is constructed with genetic algorithm (GA), it can schedule FF system without jitter. Scheduling condition is discussed at last.