Optimizing fishbone aisles for dual‐command operations in a warehouse

Abstract

Unit-load warehouses store and retrieve unit-loads, typically pallets. When storage and retrieval operations are not coordinated, travel is from a pickup and deposit (P&D) point to a pallet location and back again. In some facilities, workers interleave storage and retrieval operations to form a dual-command cycle. Two new aisle designs proposed by Gue and Meller ("Improving the unit-load warehouse." In Progress in Material Handling Research: 2006. Material Handling Industry of America, Charlotte, NC, 2006) use diagonal aisles to reduce the travel distance to a single pallet location by approximately 10 and 20% for the two designs, respectively. We develop analytical expressions for travel between pallet locations for one of these-the fishbone design. We then compare fishbone warehouses that have been optimized for dual-command to traditional warehouses that have been optimized in the same manner, and show that an optimal fishbone design reduces dual-command travel by 10-15%.

To the question about the layout of the racks in the warehouse

“…Значительный эффект повышения эффективности работы может быть получен ради-кальным изменением схемы расположения, которое было предложено в [23][24][25][26]. V-образная схема размещения проходов имеет изогнутый поперечный проход, который позволяет уменьшить расстояние, проходимое за полный цикл подъёмно-транспортного оборудования от мест погрузочно-разгрузочного участка до мест хранения грузов за счёт «евклидового преимущество» (рис.…”

Incorporating vertical travel into non-traditional cross aisles for unit-load warehouse designs

“…Previous research used travel distances to draw comparisons Pohl et al, 2009Pohl et al, , 2011, However, our model, which incorporates vertical travel, must use travel times. Adding vertical travel to the model introduces a new parameter, the number of levels of storage in the facility (H).…”

“…Previous research multiplied the expected travel by the probability of a pick in the section to find a total expected travel distance Pohl et al, 2009). However, because Section II can simultaneously exist or not exist in the same picking aisle depending on the height, it is helpful to combine the Section I and II travel times before continuing to total expected travel time.…”

Analytical models for a new turnover-based hybrid storage policy in unit-load warehouses

“…Dual-command policy offers benefits by combining storage of an item with retrieval of another item in the same trip. However, it requires a good algorithm to pair product retrievals and picking (see Meller and Gue 2009;Pohl, Meller, and Gue 2009).…”