Abstract: In modern mass production,the production capacity of the assembly line is limited not only by the unreliability of the equipment and the finiteness of the buffers,but also by the uncertainty of parts supply.Considering the impact of parts supply on assembly lines,the performance evaluation and inventory control of two-machine assembly lines with parts inventories was studied.For assembly workstation consisting of one assembly machine and one part inventories,a Markov chain model was established to interpret the dynamics of assembly workstation with (s,S) policy.Closed-form formulae for the steady state probability distribution were derived.For two-machine assembly lines,the assembly workstation was equivalent to one machine.Analytical formulae of performance indicators were derived.Furthermore,an inventory control model was formulated to balance inventory related cost and productivity.An adaptive Genetic algorithm was utilized to solve the inventory control model.The case studies were carried out to validate the accuracy of the proposed performance evaluation method and analyze the monotonicity of performance indicators to inventory control thresholds,as well as the variation trends of optimal control thresholds with assembly machine parameters.The results showed that this study provided effective methods of performance evaluation and inventory control for assembly lines with parts inventories.

Key words: assembly line, performance evaluation, (s,S) inventory control policy, inventory control

摘要： 对于面向大批量生产的装配线而言,其产出能力不仅受到设备不可靠性和缓冲有限性的限制,还受到外部零件供给不确定性的影响。以考虑零件库存的两机器装配线为研究对象,研究了(s,S)库存控制策略作用下装配线的性能评估与库存控制问题。首先,针对由一台装配机器和零件库存组成的装配工站,分析了(s,S)库存控制策略对系统状态转移过程的影响,利用马尔可夫链建立了装配工站的性能评估模型,求得了系统稳态概率分布的闭集表达式。其次,针对由两个装配工站组成的装配线,将一个装配工站等效为一台独立机器,进而利用马尔可夫链求得了主要性能指标的解析表达式。再次,以最小化库存相关成本为目标,以产出率满足市场需求为约束条件,构建了(s,S)库存控制阈值优化模型,并利用自适应遗传算法对模型进行了求解。最后,通过数值实验验证了所提性能评估方法的准确性,并分析了性能指标关于库存控制阈值的单调性以及最优控制阈值随装配机器参数的变化趋势。实验结果表明,本研究为考虑零件库存的装配线提供了一种有效的性能评估与库存控制方法。

关键词: 装配线, 性能评估, (s,S)库存控制策略, 库存控制