基于一种新的评价指标的可重入生产系统调度

可重入生产系统的调度研究对制造业的发展具有重要的实际意义和理论价值。然而许多动态调度寻优方法需要将系统表示成有限的离散时间Markov过程．而常用的平均输出率作为评价指标时无法找到具有明确物理意义的状态作为Markov过程的吸收态。本文针对以上情况，对封闭可重入生产系统提出将系统某调度策略下首次进入阻塞前的平均输出工件个数作为评价谊策略性能的新标准，并通过计算二站四缓冲区系统四种静态优先策略下的以上两种评价指标验证新标准的合理性；将系统首次进入阻塞前的平均输出工件个数作为优化目标表示成新形式的代价值函数、转移代价函数，应用到神经元动态规划策略中，对封闭可重入生产系统进行调度策略优化，并将对系统内工件个数较少时获得的调度策略直接应用到系统内工件个数较多的生产系统中，获得满意的蛄果，进一步验证系统首次进入阻塞前的平均输出工件个数可作为平均输出率的有效替代。

A Scheduling Research of Re-entrant Lines Based on a New Evaluating Criterion

Scheduling of re-entrant lines is very important for manufacturing systems.It is necessary to model the(production) system with finite-state discretetime Markov process for some dynamic scheduling methods.However,proper state can not be found as absorbing state of Markov process when general mean output rate is employed as the evaluating(criterion.) Mean Output Number of parts Before First Block(MONBFB) is presented to be an new evaluating criterion in this paper to evaluate scheduling policies for closed re-entrant lines.Simulations of 4 static scheduling policies verify the new(criterion.) Furthermore,cost-to-go value function and transfer value function of neuro-dynamic programming are presented to new forms under the new criterion to schedule a closed re-entrant line.The policy obtained in less-number parts system is applied in more-number parts system directly,whose result is satisfactory.