Abstract: To meet the material transportation needs between multi-floor production workshops and reduce the cost of enterprises,it is becoming more and more important to consider the design of Autonomous Vehicle Storage and Retrieval System (AVS/RS).The AVS/RS with multi-level rack has good application prospects due to its excellent throughput capacity and flexibility.To analyze the parallel operation performance of AVS/RS with multi-level rack in a multi-floor workshop,a semi-open queueing network model was constructed based on the analysis of AGV,elevator and telescopic arm operation mode,and an approximate solution algorithm based on the approximate mean value analysis method was designed.The method first divided the internal network of the semi-open queueing network into different individual network models and reconstructed each into an equivalent closed queueing network model.These network models were eventually aggregated into a node that jointly constructed a closed queueing network model to solve for the throughput rate with an external synchronous node.Other performance indicators were obtained by analyzing individual nodes of the internal network.The effectiveness and accuracy of the proposed method were verified by designing simulation experiments.

Key words: autonomous vehicle storage and retrieval system, multi-level rack, parallel operation, queuing network model, performance analysis

摘要： 为了满足多楼层生产车间之间的物料运输需求,同时减少企业成本,自动存取系统的设计问题变得愈发重要。带有多层级货架的自动小车存取系统因其优秀的吞吐能力和柔性,具有很好的应用前景。为了分析多层车间中带有多层级货架自动小车存取系统并行作业的性能,在分析自动导引小车（AGV）和电梯、伸缩臂作业方式的基础上,构建了半开排队网络模型,并设计了基于近似均值分析法的近似求解算法。该方法首先将半开排队网内部网络分为不同的单独网络模型,并分别重构为等效的闭排队网络模型。这些网络模型最终被聚合成一个节点,与外部的同步节点联合构建闭排队网络模型求解吞吐率。最后,针对内部网络的单独节点进行分析计算,得到其他系统性能指标。通过设计仿真实验,验证了所提方法的有效性和准确性。

关键词: 自动小车存取系统, 多层级货架, 并行作业, 排队网络模型, 性能分析