運用系統模擬與基因演算法執行限制理論於流線型生產

Integrating Simulation and Genetic Algorithms to Implement TOC in Flow-Shop Scheduling

張玉鈍(Yu-Tun Chang) ； 諶承正(Nelson C. C. Cheng)

《大葉學報》 11卷2期 (2002/12) Pp. 99-106

https://doi.org/10.7119/JDYU.200212.0099

摘要

限制驅導式乃限制理論運用於現場排程的技術，其主要精神為充份利用瓶頸或限制資源，確保整體產出的最大化。為了使限制資源產能被充分發揮，其主要技巧在於緩衝的管理，及移運批量的彈性運用；緩衝管理係靠投料站之投料時間來實現的，而移運批量的彈性運用旨在避免大批量造成過多的在製品及扺達限制資源之批量過於斷續，致使限制資源出現待料情形。若由生管人員依直覺與經驗來決定限制驅導式排程法的移運批大小與投料時間有其困難，本研究嘗試以基因演算法搜尋移運子批量及其在限制資源的排程順序以減化排程人員負擔。本研究以VB語言撰寫基因演算法程式，自動連結模擬軟體Arena進行排程模擬，在排程模擬的設計上先就限制資源從事細部排程，再就限制資源前、後之製程各以左推法及右推法排定細部排程，並以最短完工時間及最短總流程時間為目標函數，運用基因演算法，循環搜尋近似最佳解。本研究發展限制資源先排序法，並與投料製程站先排序的三種模式進行模擬比較，其中並將移運批量的分割模式分為不等批批量與等批批量兩種，為了評估本研究所提方法在各種製程狀況之適用性，亦針對次限制資源在不同位置加以模擬。模擬結果發現本研究所提方法在縮短總完工時間及總流程時間有顯著的效益。

關鍵字

排程 ； 限制理論 ； 基因演算法 ； 移運批 ； 限制驅導式

並列摘要

Transfer batch and buffer management are two key elements in successfully implementing the Drum-Buffer-Rope technique, which is a well-known shop-floor control method based on the theory of constraints. A production planner often encounters difficulties in determining the transfer-batch size and the schedule for entrance stations. In this study a systematic framework is developed to search the sizes of transfer batches and the sequencing of the bottleneck and gate stations. A genetic algorithm is employed to search for the transfer-batch sizes and sequences of the sublots on the constraint resources. Then, the backward method is used to schedule the non-constraint resources preceding the constraint, and the forward method is used to schedule the non-constraint resources succeeding the constraint. The simulation package Arena is used to accomplish the detailed schedule. The proposed approach is compared with three other methods that employ the forward method. The effect of equal and non-equal transfer batches and the effect of the location of the sub-constraint relative to the constraint are also observed. The results show that the proposed framework can achieve significant improvement with regard to the objectives of makespan and total-flow time.

並列關鍵字

scheduling ； theory of constraints ； genetic algorithm ； transfer batch ； drum-buffer-rope