考虑经济相关性和缓冲库存的串并联系统维修策略优化

Serial-parallel systems are widely used in manufacturing industry. Therefore, the productivity enhancement and maintenance cost reduction attracts intensive attention from industrial and academic communities. However, the economic dependence and intermediate buffers that widely exist in serial-parallel systems can make the modelling and solving algorithm of maintenance strategy optimisation very difficult. Existing research about the maintenance strategy optimisation of serial-parallel systems does not pay enough attention to the economic dependence among units and intermediate buffers, which limits the effects of maintenance optimisation. This project considers the two factors during the maintenance optimisation of serial-parallel systems. Firstly, a system with economic dependence among units in subsystems is investigated. Then intermediate buffers are further considered during maintenance optimisation. Finally, case studies using models and algorithms proposed in this research are performed. This project investigates three specific scientific problems, i.e., (1) the modelling of degradation process of subsystems when economic dependence exists, (2) evaluation of productivity and maintenance cost of a serial-parallel system with multiple intermediate buffers, and (3) the construction of optimisation space of the maintenance strategies. The outcome of this project will provide theoretical and decision support for the maintenance strategy optimisation and productivity enhancement of production systems.

串并联系统普遍存在于现代制造业中，如何提高其生产效率和降低维修成本已引起工业界和学术界的广泛重视。然而，串并联系统中通常包含的经济相关性和缓冲库存问题使维修策略优化变得非常复杂。目前针对串并联系统的维修策略研究并未充分关注这两个因素，以至于在实际应用中难以获取预期成效。本项目将同时考虑各单元间经济相关性和子系统间缓冲库存的影响，进行串并联系统维修策略优化的研究。首先，考虑无缓冲库存的子系统内部经济相关性；其次，考虑子系统间缓冲库存的影响；最后，将选择实际制造系统进行案例研究，验证所提模型和方法的科学性。在此过程中，本项目将解决如下三个关键科学问题：（1）考虑经济相关性后子系统状态的描述及退化过程的数学建模；（2）含有多个缓冲库存的串并联系统的生产率评估和维修成本计算；（3）串并联系统维修策略优化空间的构建。本项目的研究成果将为制造系统维修策略的优化和生产效率的提高提供理论依据和决策支持。

本项目围绕包含缓冲库存制造系统的维修优化问题进行了深入研究。首先，研究了考虑子系统内部经济相关性的串并联系统维修策略优化，对包含经济相关性之后的系统退化过程建模、维修策略结构和维修优化方法进行了探索。然后，研究了考虑子系统内部经济相关性和子系统间缓冲库存的串并联系统生产率评估和维修成本计算。对含有缓冲库存的制造系统退化过程进行了建模，并采用解析方法研究了缓冲库存对维修成本和最优维修策略结构的影响。最后，本项目对铁路机车故障的实际数据进行可靠性建模，得出了机车故障分布的季节性特征。并根据实际需求，研究了机车维修中的成组维修和拟周期维修问题。研究成果撰写成7篇论文发表于SCI期刊，受理发明专利3项。培养毕业博士两名硕士一名，另有一名在读博士研究生也参与了本项目。圆满完成了申请书中提出研究目标和任务。