两种多层穿梭车系统的性能比较分析

物流配送中心订单响应速度的加快,对订单拣选系统提出了更高的要求。多层穿梭车系统因其柔性强、效率高等特点,近年来得到了广泛应用。多层穿梭车系统具有两种形式--基于转载车和基于环形输送线,二者均可实现货物的快速拣选,但在系统吞吐量和订单完成周期方面存在差异,致使企业决策者难以进行系统选择。基于上述原因,本文比较两种多层穿梭车系统的性能差异。建立两个系统的开环排队网络模型,然后求解系统吞吐量、订单完成周期,通过仿真验证了排队论模型的准确性,通过试验对两种系统的性能进行对比分析。结果表明,系统吞吐量与层数、巷道数相关,层数越多,巷道数越少,转载车系统相对于环线系统优势越显著;订单完成周期与层数、订单到达率相关,层数越多,订单到达率越低,转载车系统相对于环线系统越具优势。

Comparative Analysis of Performance for Two Kinds of Automated Vehicle Storage/Retrieval Systems

The quicker responding time of orders demands a more efficient order fulfilment system in the distribution centre. The automated vehicle storage/retrieval system (AVS/RS) has been widely used in recent years due to its flexibility and high efficiency. The AVS/RS has two mechanical structures-one is based on cross-aisle shuttles and another is based on a ring-shaped conveyor. Both of above systems can fulfill the orders rapidly,however,there are differences in two aspects including the system throughput and order cycle time which makes the warehouse manager hard to make decision when choosing the systems. Based on the above reasons,this paper compares the performance differences of two kinds of AVS/RS. The open queuing network models of two systems are built,and then the system throughput and order cycle time are calculated. The open queuing network models are verified by simulation. The performance of the two systems are compared. The results show that the system throughput is related to the number of tiers and lanes of AVS/RS. The AVS/RS with cross-aisle has more advantages when there are more tiers and fewer lanes. Similarly,the order cycle time is related to the number of tiers and order arrival rate. The AVS/RS with cross-aisle has more advantages when there are more tiers and smaller order arrival rate.