本研究探討多樓層物流倉儲系統中訂單撿貨問題，在人口稠密度高的地區，例如：台灣與歐洲因土地利用成本高昂，多樓層物流設施可以大幅節省土地成本，但多樓層倉儲系統之設計與作業均為新興問題，鮮少有學者提出相關研究；在實務上，多樓層設施必須仰賴垂直移動設備，其成本又遠較水平移動成本為高，多樓層設施之垂直搬運特性亦影響到物流系統整體成本與績效表現，而傳統的單樓層訂單撿貨模式與解法無法有效地解決此類設施實際訂單撿貨問題。本研究針對多樓層物流系統中訂單撿貨問題，考量垂直與水平移動成本之綜合效應，提出一套快速而品質佳之訂單撿貨問題解決方法，以最小化撿貨之相關成本。

本文中多樓層物流倉儲設施佈置假設為已知或給定，各樓層儲架位置固定，在各物件儲位確定的前提下，撿貨員操控台車在系統內進行訂單撿貨，樓層之間透過垂直移動設備貫穿連結。本研究首先針對多樓層倉儲系統訂單撿貨問題建構數學規劃模式，目標函數包含不同樓層之間的垂直移動成本與同一樓層內的水平移動成本，受限於數學模式之困難度，本研究發展兩個有效率的啟發式演算法，以期求得多樓層倉儲系統訂單撿貨問題的最佳解或近似最佳解，第一種方法為最近撿貨品項演算法，利用選取最小成本撿貨點的方式進行訂單撿貨；第二種方法為走道內最小移動相關成本演算法，在撿完整層樓才可移動至另一樓層的規則下，走道內採取最短路徑法決定撿貨順序；實驗結果發現當撿貨數與倉儲系統樓層數少時，最近撿貨品項演算法有較好的求解品質，但當倉儲系統樓層數與撿貨數量增多時，走道內最小移動相關成本演算法因可反應此類型問題特性，而有較好的求解品質。

We consider the order picking problem in a multiple-level warehouse, where a picker traverses through different levels and different aisles to pick an order with multiple items. In recent years, this multi-floor order picking system has become very popular in metropolitan areas where the cost to erect traditional single floor warehouse is prohibited, due to land restriction or other constraints.

In this order picking system, the multiple-level warehouse layout is assumed known beforehand. Each floor includes multiple aisles with equal length and width. Items to be picked are stored with dedicated storage policy. Vertical transfer lifts are used to transport the picker from one floor to another. A picking tour is a specification of the sequence in which items in the specific order will be picked. For the specific order, the picker leaves the I/O point on the first floor, and traverses from one storage area to another between aisles and levels to pick the items, and finally returns to the I/O station.

Due to the computational complexity, two efficient heuristics are developed in this thesis. The nearest item heuristic is a greedy procedure where the nearest item to the picker’s current position is selected. The minimum within-aisle picking cost procedure is a decomposition approach that finds the minimal within-aisle traversal cost one by one. Numerical experiments have shown that the first algorithm gives better solution quality when the number of items to be picked or the number of levels is small. When the number of items to be picked is large, the second algorithm gives better solution quality.

中文部分：

郭獻隆(2003)， “多樓層倉儲系統中專用儲位與垂直搬運設備之佈置設計”，國立成功大學工業管理研究所碩士論文。

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