规则调度的迭代优化

Iterative Optimization of Rule-Based Scheduling

将调度系统性能指标分为设备关联指标和工件关联指标。设备关联指标与设备实际加工时间关联 ,工件关联指标与工件加工时间、流动时间和交货期关联 ,对应系统性能分为设备关联性能和工件关联性能 ,这两类系统性能均随设备 /工件优先级改变而改变。引入能反映上述性能指标的控制参数 ,提出基于性能反馈的迭代优化调度方案 ,开发了实验原型系统。仿真实验结果表明 ,迭代优化调度能有效提高系统性能 ,并根据调度目标函数 。

Performance criteria of production scheduling system was divided into two categories: equipment-associated criteria (EAC) and job-associated criteria (JAC). The EAC are mainly related to the processing time of equipment while the JAC are related to the processing time, flow time and due date of jobs. Accordingly performance of the production scheduling system falls into two categories, that is, performance associated with equipment (PAE) and performance associated with jobs (PAJ). Both kinds of the performances are affected by the priority of equipment and jobs during scheduling. Based on the above observations we defined adjustable parameters that reflect the PAE and the PAJ respectively, and established the relationship between the parameters and the two kinds of performances. With the help of the parameters, a performance-feedback iterative optimization scheme for rule-based production scheduling was proposed and furthermore a scheduling prototype system was developed. The experimental results demonstrated that the proposed scheduling scheme can improve the total performance of manufacturing systems. Especially it can optimize the specific performances significantly according to the scheduling objective function.