A Study of Flexibility on Manufacturing System-An Operations Research Approach

研究了柔性制造系统(FMS)等现代自动化制造系统的柔性对其计划和控制的影响。具体分析了柔性对调度和调度优化的影响，以及机器柔性减少作业次数的影响。主要研究结果如下：(1)利用FMS模拟器对FMS中调度规则的执行情况进行了分析。模型中考虑了自动装料装置、托盘数量有限、缓冲器尺寸有限等因素，并对其影响进行了分析。结果表明，基于加工时间的简单(但新的)调度规则在不存在路径柔性的情况下具有良好的性能。(2)利用柔性的“协作调度”作为FMS的关键特性之一的路径柔性在传统的调度规则下没有得到充分的利用。为了最大限度地利用路由灵活性，提出了一种称为协同调度的新方案。大量的仿真研究表明，作业和机器之间的协作可以改善交货期满意度、机器利用率和作业流时间等性能指标。(3)FMS中的调度优化

This research project studied the effects of flexibility of modern automated manufacturing systems such as flexible manufacturing systems (FMSs) on their planning and control. In particular, the effects of flexibility on dispatching and schedule optimization have been analyzed in detail together with the effects of the reduction of the number of operations due to flexibility of machines.Main results are summarized below :(1) performance evaluation of dispatching rules in FMSPerformance of dispatching rules in FMS has been analyzed using detailed FMS simulator. Such factors as automatic material handling devices, finite number of pallets, finite size of buffer are included in the model, and their effects analyzed. The results show that processing-time-based simple (but new) dispatching rules give good performance when there exist no routing flexibility.(2) "cooperative dispatching" to exploit flexibilityAs routing flexibility, which is one o the key characteristics of FMSs, is not fully exploited under the traditional dispatching rules. To best utilize routing flexibility, a new scheme called Cooperative Dispatching has been proposed. Extensive simulation study shows that the cooperation between jobs and machines lead to improvement in performance measures such as due-date satisfaction, machine utilization, and job flow time.(3) optimization of dispatching in FMS