Equilibria, Stability, Oscillations, Chaos, and Transients in Re-entrant Lines

重入线中的平衡、稳定性、振荡、混沌和瞬变

• 批准号: 1160968
• 负责人: Semyon Meerkov
• 金额: $ 35万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-15 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1160968&HistoricalAwards=false
• 关键词: Equilibria; Stability; Oscillations; Chaos; Transients

This research project is devoted to performance analysis and improvement of production systems widely used in semiconductor manufacturing - the re-entrant lines. It is universally accepted that performance of re-entrant lines is characterized by large variability and oscillations of the throughput (TP) and work-in-process (WIP). This leads to performance degradation and long and unpredictable production cycle time. At present, no rigorous explanations of these phenomena are available, and the attempts to combat them are far from being successful. The research is intended to develop a theory that explains fundamental reasons for these phenomena and provide techniques for their alleviation. The approach is based on the methods of nonlinear dynamics. Specifically, the project will investigate steady states of re-entrant lines, their (Lyapunov) stability properties, periodic and chaotic oscillations, and transient behavior (i.e., the processes of convergence to steady states after machine breakdowns). As a result, the project will provide analytical tools for investigating the performance of re-entrant lines, including TP and WIP variability, and offer quantitative methods and qualitative insights that can be used by production personnel to mitigate the undesirable dynamic phenomena.The broader impact of this research will be attained through industrial short courses to be offered by the PI at semiconductor manufacturing plants. These courses will present the results of this research in the format appropriate for factory floor applications. The PI has been offering similar courses in the automotive industry for over ten years, where the results of prior NSF-supported research on serial lines and assembly systems have been presented. As an outcome, some of these results have been incorporated in standard operating procedures at several automotive plants and led to a substantial performance improvement. Similar outcomes are expected to be obtained in the semiconductor industry as well.

本研究项目致力于半导体制造中广泛使用的生产系统--再入生产线的性能分析和改进。人们普遍认为，可再入生产线的性能特征是吞吐量(TP)和在制品(WIP)的大波动和振荡。这会导致性能下降和漫长且不可预测的生产周期时间。目前，对这些现象没有严格的解释，打击这些现象的努力也远未成功。这项研究旨在发展一种理论，解释这些现象的根本原因，并提供缓解这些现象的技术。该方法基于非线性动力学方法。具体地说，该项目将研究可再入生产线的稳态、其(Lyapunov)稳定性、周期和混沌振荡以及暂态行为(即机器故障后收敛到稳态的过程)。因此，该项目将为调查可再入生产线的性能提供分析工具，包括TP和WIP变异性，并提供可供生产人员使用的定量方法和定性见解，以减轻不良动态现象。这项研究的更广泛影响将通过半导体制造工厂的PI提供的工业短期课程来实现。这些课程将以适合工厂现场应用的格式介绍这项研究的结果。十多年来，PI一直在汽车行业提供类似的课程，其中展示了之前由NSF支持的关于串行线和装配系统的研究结果。结果，这些成果中的一些已被纳入几家汽车工厂的标准操作程序，并导致了显著的性能改进。预计半导体行业也将获得类似的结果。