Aisle

About: Aisle is a research topic. Over the lifetime, 361 publications have been published within this topic receiving 4879 citations.

Routing methods for warehouses with multiple cross aisles

Abstract: This paper considers routing and layout issues for parallel aisle warehouses. In such warehouses order pickers walk or drive along the aisles to pick products from storage. They can change aisles at a number of cross aisles. These cross aisles are usually located at the front and the back of the warehouse, but there can also be one or more cross aisles at positions in between. We describe a number of heuristics to determine order picking routes in a warehouse with two or more cross aisles. To analyse the performance of the heuristics, a branch-and-bound algorithm that generates shortest order picking routes is used. Performance comparisons between heuristics and the branch-and-bound algorithm are given for various warehouse layouts and order sizes. For the majority of the instances with more than two cross aisles, a newly developed heuristic appears to perform better than the existing heuristics. Furthermore, some consequences for layout are discussed. From the results it appears that the addition of cros...

Routing policies and COI-based storage policies in picker-to-part systems

Abstract: The paper evaluates and compares the expected travel distance for different routing strategies- namely traversal and return policies in low-level pickerto-part systems. Items are assigned to storage locations on the basis of the ratio of the required space to the order frequency (cube-per-order index or COI). The focus is on narrow-aisle systems, in which the distance travelled crossing the aisle from one side to the other is negligible compared to the distance travelled along the centreline of the aisle. For both routing policies, an efficient COI-based stock location assignment strategy is first developed. Second, analytical models are derived which relate the expected travel distance required to fill an order to the main system parameters (i.e. the COI-based ABC curve; the number of picks in a tour; the number, length and width of aisles). Simulation results confirming the accuracy of the analytical models are presented. Finally, preference regions as a function of the number of picks in a tour and dif...

Order Picking In An Aisle

Abstract: A classical order picking problem is the case where items have to be picked from both sides of an aisle and the picker cannot reach items on both sides without changing position. Hence the picker must cross the aisle one or more times. An efficient optimal algorithm is developed and shown to yield policies with up to 30% savings in travel time over commonly used policies. It is also shown that, for most practical aisle widths, it is significantly more efficient to pick both sides of the aisle in the same pass (a traversal policy) rather than pick one side and then pick the other side (a return policy) unless the pick densities are greater than 50%. All the algorithms presented here can be implemented in real time on a microcomputer.

Aisle configurations for unit-load warehouses

Abstract: Unit-load warehouses are used to store items—typically pallets—that can be stowed or retrieved in a single trip. In the traditional, ubiquitous design, storage racks are arranged to create parallel picking aisles, which force workers to travel rectilinear distances to picking locations. We consider the problem of arranging aisles in new ways to reduce the cost of travel for a single-command cycle within these warehouses. The proposed models produce alternative designs with piecewise diagonal cross aisles, and with picking aisles that are not parallel. One of the designs promises to reduce the expected distance that workers travel by more than 20% for warehouses of reasonable size. We also develop a theoretical bound that shows that this design is close to optimal.