外文翻譯--關(guān)于自動化立體倉庫使用雙貨叉的探討

1、<p><b>　　附錄A </b></p><p><b>　　英文原文</b></p><p>　　An Analysis of Dual Shuttle Automated</p><p>　　Storage/Retrieval Systems</p><p>　　An Analys

2、is of Dual Shuttle</p><p>　　Automated Storage/Retrieval Systems </p><p>　　Adhinarayan Keserla</p><p>　　Brett A. Peters </p><p><b>　　Abstract:</b></p>

3、<p>　　This paper addresses the throughput improvement possible with the use of a dual shuttle automated storage and retrieval system. With the use of such a system, travel between time in a dual command cycle is vi

4、rtually eliminated resulting in a large throughput improvement. The dual shuttle system is then extended to perform an equivalent of two dual commands in one cycle in a quadruple command mode (QC). A heuristic that seque

5、nces retrievals to minimize travel time in QC mode is developed. Monte C</p><p>　　Key words:</p><p>　　Automated Storage/Retrieval Systems Design; Automated Storage/Retrieval Systems Operation; M

6、aterial Handling Systems; Performance Modeling and Analysis </p><p>　　Introduction:</p><p>　　Automated storage/retrieval systems (AS/RS) are widely used in warehousing and manufacturing applicat

7、ions. A typical unit load AS/RS consists of storage racks, S/R machines, link conveyors, and input/output (I/O) stations. An important system performance measure is the throughput capacity of the system. The throughput c

8、apacity for a single aisle is the inverse of the mean transaction time, which is the expected amount of time required for the S/R machine to store and/or retrieve a unit load. The</p><p>　　Han et al. [2] imp

9、roved the throughput capacity of the AS/RS through sequencing retrievals. Intelligently sequencing the retrievals can reduce unproductive travel between times when the S/R machine is traveling empty and thereby increase

10、the throughput. They develop an expression for the maximum possible improvement in throughput if travel between is eliminated for an AS/RS that is throughput bound and operates in dual command mode. In essence, this mean

11、s that if the S/R machine travels in a sin</p><p>　　In this paper, we analyze an alternative design of the S/R machine that has two shuttles instead of one as in a regular AS/RS. The new design eliminates th

12、e travel between the storage and retrieval points and performs both storage and retrieval at the point of retrieval, thereby achieving the maximum throughput increase calculated by Han et al. [3]. </p><p>　　

13、The dual shuttle AS/RS is a new design aimed at improving S/R machine performance. Most studies on AS/RS systems have been based on a single shuttle design. In our analysis of the dual shuttle AS/RS performance, we build

14、 upon these previous research results. </p><p>　　1 Alternative S/R Machine Design</p><p>　　A typical unit-load AS/RS has an S/R machine operating in each aisle of the system. The S/R machine has

15、 a mast which is supported at the floor and the ceiling and travels horizontally within the aisle. Connected to this mast is a shuttle mechanism that carries the unit load and moves vertically up and down the mast. The s

16、huttle mechanism also transfers loads in and out of storage locations in the rack. Figure 1 provides an illustration of the single shuttle S/R machine. </p><p>　　Figure 1. Single Shuttle S/R Machine Design &

17、lt;/p><p>　　A typical single shuttle AS/RS can perform a single command cycle or a dual command cycle. A single command cycle consists of either storage or retrieval. For storage, the time consists of the time

18、to pickup the load at the I/O point, travel to the storage point, deposit the load at that point, and return to the I/O point. The time for retrieval is developed similarly. </p><p>　　A dual command cycle in

19、volves both storage and retrieval in the same cycle. The cycle time involves the time to pickup the load at the I/O point, travel to the storage location, place the load in the rack, travel empty to the retrieval locatio

20、n, retrieve a load, return to the I/O point, and deposit the load at the I/O point. </p><p>　　If we critically analyze the dual command cycle of the S/R machine (shown by the solid line in Figure 2), a poten

21、tial open location for a future storage is created when a retrieval is performed. Furthermore, if both a retrieval and a storage are performed at the same point, the travel between time (TB) is eliminated, and the travel

22、 time will be equal to the single command travel time. With the existing AS/RS design, this mode of operation is not possible; therefore, an alternative to the S/R mac</p><p>　　Figure 2. Dual Command Travel

23、Paths of S/R and R/S Machines </p><p>　　2 R/S Machine Operations</p><p>　　Consider an S/R machine with two shuttle mechanisms instead of one. This new S/R machine could now carry two loads simul

24、taneously. Each shuttle mechanism could operate independently of the other, so that individual loads can still be stored and retrieved. An illustration of the dual shuttle S/R machine is shown in Figure 3. This new S/R m

25、achine would operate as described below. </p><p>　　Figure 3. Dual Shuttle S/R Machine Design </p><p>　　The S/R machine picks up the item to be stored from the I/O point, loads it into the first

26、shuttle, and moves to the retrieval location. After reaching the retrieval location, the second shuttle is positioned to pickup the item to be retrieved. After retrieval, the S/R machine positions the first shuttle and d

27、eposits the load. The S/R machine then returns to the I/O point. The operation can easily be seen as a single command operation plus a small travel time for repositioning the S/R machine be</p><p>　　Since th

28、e R/S machine has two shuttles, the position of the shuttles has a role in the operation of the system. With two shuttles, the R/S machine is able to perform a dual command cycle at one location in the rack. This operati

29、on is accomplished by first retrieving the load onto the empty shuttle, transferring the second shuttle into position, and storing the load into the empty location in the rack. However, the choice of shuttle configuratio

30、n does not impact the analysis in this paper. </p><p>　　To perform these operations, the R/S machine must move the second shuttle into position after the first shuttle has completed the retrieval. Due to the

31、 small distance involved, the R/S machine will use a slower creep speed for positioning, but this travel time is generally small. Furthermore, an amount of creep time is usually included in the pickup and deposit time to

32、 account for this required positioning. A second design characteristic is that additional clearance beyond the first and last row</p><p>　　3 Throughput Improvement</p><p>　　To estimate the throu

33、ghput improvement by the dual shuttle system over existing designs, we use the expressions for single command and dual command cycle times developed by Bozer and White [1] and the tabulated values for the nearest neighbo

34、r heuristic from Han et al. [4]. In developing the expressions, the authors in [1] and [4] made several assumptions. The same assumptions hold for the new design and include the following. </p><p>　　1 The ra

35、ck is considered to be a continuous rectangular pick face where the I/O point is located at the lower left-hand corner of the rack. </p><p>　　2 The rack length and height, as well as the S/R machine velocity

36、 in the horizontal and vertical directions, are known. </p><p>　　3 The S/R machine travels simultaneously in the horizontal and vertical directions. In calculating the travel time, constant velocities are us

37、ed for horizontal and vertical travel. Acceleration and deceleration effects are implicitly accounted for in either a reduced top speed or an increased pickup and deposit time. A creep speed is used for repositioning the

38、 dual shuttle. </p><p>　　4 Pickup and deposit times associated with load handling are assumed constant and, therefore, these could be easily added into the cycle time expressions. </p><p>　　5 Th

39、e S/R machine operates either on a single or dual command basis, i.e., multiple stops in the aisle are not allowed. (This assumption is later relaxed for the new R/S machine to perform a quadruple command cycle.) </p&

40、gt;<p>　　6 For the nearest neighbor heuristic, a block of n retrievals is available for sequencing and there are m initial open locations in the rack face. </p><p>　　4 Dual Shuttle S/R Systems</p&

41、gt;<p>　　The new design of the S/R machine has two shuttles and therefore could be operated as a dual shuttle system: carrying two loads and depositing them, retrieving two loads, and returning to the I/O point to

42、 deliver them as shown in Figure 4. The above operation can be performed by storing and retrieving the loads at four different locations. Therefore, the travel time would consist of the time for a single command travel p

43、lus three travel between times. To more efficiently perform the 4 operations</p><p>　　5 Conclusions</p><p>　　This paper performs an analysis of dual shuttle automated storage and retrieval syste

44、ms. Several contributions have been made including the following. </p><p>　　1 Throughput improvements in the range of 40-45% can be obtained using the quadruple command cycle relative to dual command cycles

45、with a single shuttle system. </p><p>　　2 With the dual shuttle design, travel between is virtually eliminated for a dual command cycle. </p><p>　　The dual shuttle system shows promise for situ

46、ations requiring high throughput. The main disadvantage with the new design is the extra cost of the S/R machine. An economic evaluation is needed to determine if it is appropriate for a particular situation. However, ba

47、sed on throughput performance, the dual shuttle design appears promising. </p><p>　　The concept of dual shuttle systems can also be extended to other material handling systems. Furthermore, research is neede

48、d to consider other storage strategies, such as class based storage policies, to examine their impact on throughput in conjunction with the dual shuttle design. This paper provides a framework for analyzing dual shuttle

49、AS/RS, and it provides a foundation for other material handling research related to this conc.</p><p><b>　　附錄B</b></p><p><b>　　中文譯文</b></p><p>　　關(guān)于自動化立體倉庫使用雙

50、貨叉的探討</p><p>　　Adhinarayan Keserla</p><p><b>　　布雷特 A. 彼得</b></p><p><b>　　摘 要:</b></p><p>　　本文主要探討的是可以提高生產(chǎn)效率的雙貨叉立體倉庫系統(tǒng)。通過使用該系統(tǒng)，可以縮短堆垛機在一個雙任務(wù)流程中的

51、運行時間，從而大大提高了倉庫的工作效率。雙貨叉?zhèn)}庫系統(tǒng)相當(dāng)于一個四任務(wù)指令模塊（quadruple command mode簡稱QC）中的雙指令任務(wù)書流程。一個很有建設(shè)性的思想被提出來，即通過堆垛機按某一順序運行可以縮短在一個（QC）中的運行時間，蒙地卡羅對此進行了模擬對比實驗，實驗結(jié)果證明確實提高了堆垛機的搬運效率，這就說明了這種方案的可行性。</p><p>　　關(guān)鍵詞:自動化立體倉庫； 自動化立體倉庫的控制

52、；功能模擬和分析</p><p><b>　　1 緒論</b></p><p>　　自動化立體倉庫被廣泛地應(yīng)用于倉儲和制造設(shè)備當(dāng)中。典型的單位貨物裝卸立體倉庫由儲藏架，堆垛機，自動運輸小車，和入庫/出庫臺組成。衡量一個立體倉庫系統(tǒng)的優(yōu)劣的主要標(biāo)準(zhǔn)是倉庫系統(tǒng)的工作效率。立體倉庫的工作效率與堆垛機運行一個工作流程所需的時間成反比，這個工作流程時間包括堆垛機裝卸貨物的時間，

53、顯然堆垛機裝卸貨物的時間在一定程度上取決于堆垛機和貨架的具體結(jié)構(gòu)和規(guī)格。</p><p>　　Han 通過立體倉庫返回站點的排列提高了立體倉庫的工作能力，合理的排列返回站點堆垛機能減少不必要的行程，從而縮短了時間，提高了效率。這樣他們就提出了一種最大限度提高效率理論，即如果堆垛機在雙指令模塊流程中可以縮短運行時間那么這將最大程度的提高立體倉庫的工作效率。也就是說，如果堆垛機運行的是單命令路線，卻能完成存貨和返回的

54、動作，則工作效率的提高也就實現(xiàn)了。</p><p>　　在論文中，我們分析了一種可供選擇的堆垛機設(shè)計方法，這種設(shè)計出來的堆垛機與一般的堆垛機不同，在原來的基礎(chǔ)增加了一個貨叉，這種新穎設(shè)計的堆垛機擁有兩個貨叉，它在運作中可以縮短在貨架到返回點之間的運行時間。這種設(shè)計方案符合 Han 所說的最大效率理論。</p><p>　　雙貨叉堆垛機主要是針對如何提高堆垛機的工作能力這一問題所設(shè)計的一種新

55、穎堆垛機。目前，立體倉庫系統(tǒng)的研究是以單貨叉堆垛機為主要對象。在本文關(guān)于雙貨叉堆垛機功能的分析也是建立有前人研究的基礎(chǔ)上的。</p><p>　　2 可供選擇的堆垛機設(shè)計</p><p>　　一個基本的單一裝載立體倉庫系統(tǒng)中，每一個貨架巷道內(nèi)都有一臺可供操作的堆垛機，每臺堆垛機有一根立柱被固定在天花板和地面之間，這根立柱可以在巷道內(nèi)的水平位置移動。與立柱相連的是一個貨叉機構(gòu)，它可以載著貨物

56、沿著立柱上下移動，貨叉也可以作相對于貨格的水平取貨和存貨運動。</p><p>　　一個基本的單貨叉堆垛機立體倉庫系統(tǒng)能夠完成一個單指令作業(yè)流程也能完成一個雙指令作業(yè)流程。一個單指令作業(yè)流程由存貨和取貨組成，對于一個存貨過程所需時間包括堆垛機在入庫處裝載貨物，行駛到目標(biāo)貨格，卸下貨物，然后回到倉庫入口處這一連串動作總共所需的時間。同樣可以分析取貨過程所需時間。</p><p>　　一個雙指

57、令流程就是在同一個工作流程中完成存貨和取貨的操作。這個過程時間包括從入口處裝貨，運行到存貨貨格位置，把貨放在貨架上，空運行到取貨貨格位置，從貨架上取下貨物，回到倉庫入口處，并卸下貨物這一過程總共需要的時間。</p><p>　　如果我們對堆垛機的雙指令工作流程路線稍加分析就會發(fā)現(xiàn)，當(dāng)在完成一個取貨運作時，就暗示著可以進行下一個存貨運作，而且，如果在同一地方可以進行存貨和取貨運作，那么運行時間將被縮短，這個運行時間

58、相當(dāng)于運行一個單指令流程所需的時間。就目前已存在的立體倉庫設(shè)計，要實現(xiàn)這種操作是不可能的，因此，另外一種雙貨叉式的堆垛機就應(yīng)運而生了。</p><p><b>　　3 堆垛機的運作</b></p><p>　　設(shè)想一臺安裝了兩個貨叉的堆垛機,這種新穎的堆垛機可以同時裝載兩件貨物,為了兩件貨物分別能存庫和出庫,所以堆垛機的兩個貨叉機構(gòu)能夠相互獨立運行,具體結(jié)構(gòu)如圖3所示

59、,這種堆垛機的工作過程將在下文詳細(xì)介紹。</p><p>　　堆垛機從倉庫入口處將要被儲存的貨物裝載到第一個貨叉平臺上，然后向取貨的位置移動.到達要取貨的位置之后，第二個貨叉臺伸貨格內(nèi)取貨，當(dāng)取貨的動作完成之后，堆垛機控制第一個貨叉臺卸貨。堆垛機然后再回到入口處。這整個操作流程就像是一個單指令運作再加上一小段重新定位運行過程（即堆垛機第二個貨叉平臺裝載和卸載過程），這樣一來，其運作就像一臺堆垛機完成先完成取貨然后

60、再存貨的一個雙任務(wù)命令。</p><p>　　因為這種堆垛機有兩個貨叉平臺，所以兩個貨叉的定位控制將是系統(tǒng)的一個很重要的功能。堆垛機用兩個貨叉可以在某個貨架的同一位置完成一個存、取雙任務(wù)指令，先在空貨駐臺上取下要出庫的貨物，再移動第二貨叉到指定位置把貨物放在空貨格內(nèi)。然而，貨叉平臺結(jié)構(gòu)的選擇與本文的討論內(nèi)容無關(guān)。</p><p>　　為了實現(xiàn)上述操作，堆垛機的第二個貨叉必須在第一個貨叉完成

61、取貨動作之后才能進行定位操作。由于貨叉的定位移動量是較小的，堆垛機采用的是低速爬行方式來實現(xiàn)貨叉微小的定位移動量，在這個過程中所耗費的時間與堆垛機在裝貨卸貨耗費的時間相比一般是微乎其微的。倉庫設(shè)計的另外一個特點是第一排貨格和最后一排貨格的兩端要留有位置余量，以便在堆垛機超程時給兩個貨叉平臺留有運動余地。 </p><p><b>　　4 工作效率提高</b></p><p

62、>　　為了估算正在設(shè)計的雙貨叉系統(tǒng)工作量的提高，我們引用Bozer 和 White[1]提出的有關(guān)單任務(wù)和雙任務(wù)指令所需時間理論和Han et al.提出的最近有意義想法價值理論，這些理論家都作了種種設(shè)想，他們設(shè)想的共同部分就是我們要引用的內(nèi)容，下面就是這些理論的內(nèi)容。</p><p>　　1．倉庫的貨架被考慮成為連續(xù)矩形框架，貨物出/入處被設(shè)置在貨格的左下角位置。</p><p>

63、　　2．貨架的長度和寬度以及堆垛機水平和垂直運行的速度應(yīng)該明確。</p><p>　　3．堆垛機貨叉臺能同時在水平和垂直兩個方向運動，在計算運行時間方面作如下處理，貨叉在水平和垂直方向時進行勻速運動，加速和減速緩沖極限速度，爬行速度用來定位兩個貨叉臺。</p><p>　　4．假設(shè)與物流過程相關(guān)的裝載貨物和卸載貨物所用的時間為常量，因此，可以把它簡單的加到運行時間中去。</p>

64、<p>　　5．堆垛機只能以單指令要求和雙指令要求為基礎(chǔ)，例如，不允許堆垛機在巷道內(nèi)多次啟停。（這個分假設(shè)后來應(yīng)用于新設(shè)計的堆垛機完成四重作業(yè)流程。</p><p>　　6．為了符合最短鄰近的啟發(fā)思想， 取貨數(shù)n可用來排列，且在貨格內(nèi)有m個開放的位置。</p><p>　　5 雙貨叉堆垛機系統(tǒng)</p><p>　　新設(shè)計的堆垛機有兩個貨叉臺,因此可以對

65、其進行雙貨叉系統(tǒng)的操作:同時搬運兩件貨物并分別把它們放置在指定的位置,在不同位置取兩件貨物并回到出入口,如圖4所示.上述工作流程能通過在四個不同的位置存、取操作來實現(xiàn)。因此，運行時間將由一個單指令任務(wù)時間再加上三個運行時間。為了更有效的完成上述四個操作，在完成一個雙指令任務(wù)操作中就包含完成了在一個位置存、取操作。這種被稱為四指令任務(wù)流程的模擬操作系統(tǒng)能減少運行時間，因而比此前的所提的模擬系統(tǒng)要更能提高效率。四重指令任務(wù)流程能在倉庫的任意

66、一位置完成存儲操作，而取貨程序是按照先到先服務(wù)的原則處理。即使如此，合理的按排取貨的順序也能顯著的減少四種操作中的運行時間，Han 曾經(jīng)這樣分析以提高單貨臺立體倉庫系統(tǒng)的工作效率。本文的分析也是以他們的研究為基礎(chǔ)的。</p><p><b>　　6 結(jié)論</b></p><p>　　本文對自動化立體倉庫中的一種雙貨架堆垛機進行了較為詳細(xì)的分析，應(yīng)用這種倉儲系統(tǒng)所帶來的

67、好處表現(xiàn)在以下兩個方面：</p><p>　　1．四種操作運行中與單一貨叉的堆垛機相比，雙貨叉堆垛機可以提高工作效率的范圍是40%到45%。</p><p>　　2．一個雙任務(wù)操作中，雙貨叉的設(shè)計顯著縮短了運行時間。</p><p>　　雙貨叉系統(tǒng)使提高倉庫的工作效率成為可能。這種設(shè)計主要的缺點是要增加堆垛機的額外成本。在決定是否適合于某一特定情況時，對其經(jīng)濟估算通