模糊反馈控制实时调度算法

A Fuzzy Feedback Control Real-Time Scheduling Algorithm

为了解决模糊不确定任务集在不可预测环境下的动态抢占调度问题,应用模糊规则和模糊调度理论,提出一个基于模糊反馈控制的调度算法,并建立相应的调度架构.该架构由基本调度器和模糊反馈控制两部分组成.用模糊调度算法作为基本调度器的调度算法,将任务集按不同优先级等级进行划分,优先级等级高的任务优先调度,从而使得更多的重要任务得到调度;模糊控制器与任务流调节策略一起构成模糊反馈控制部分.仿真结果表明,模糊反馈控制调度可以很好地控制任务的截止期错失率,解决任务特征可能是模糊不确定或不可预测情况下的调度问题,提高重要任务的调度成功率.

To solve the dynamic preemptive scheduling problem of a fuzzy uncertain task set under an unpredictable environment, a scheduling algorithm, by applying fuzzy rules and fuzzy scheduling theory, is presented based on fuzzy feedback control, and its corresponding scheduling structure, composed of a basic scheduler and a fuzzy feedback controller, is established. The fuzzy scheduling algorithm is used as the scheduling algorithm of the basic scheduler. By classifying tasks into different priority levels and scheduling the task with high priority level first, more critical tasks can be scheduled. A fuzzy controller constitutes the part of the fuzzy feedback control with the adjusting policy of task flow. Simulation results show that the proposed fuzzy feedback-control scheduling can effectively control the missed deadline rate of tasks, the scheduling problem with fuzzy characteristics or unpredictable environment can be solved, and the successful scheduling rate of critical tasks can be improved.