Simulation-based Modeling and Analysis for the AGV Sorting System of Central Fill Pharmacy Systems

Recently, the Central Fill Pharmacy (CFP) market expanded with an increased number of medication packages being delivered to customers worldwide. Many typical parcel sorting systems rely on long conveyors, which require large spaces, rigid locations, and high costs. In comparison, the sorting systems equipped with Automated Guided Vehicles (AGVs), which can perform in tight spaces while providing high flexibility with lower costs, have increasingly been utilized in distribution centers and manufacturing systems. To improve the design and operation of such AGV sorting systems, this work focuses on studying the effect of the number of AGVs on the system performance by applying simulation modeling and conducting the sensitivity analysis. Numerical experiments are conducted on the simulation model of an AGV sorting system with two layers (five induction operators and 405 sorting destinations in each layer). The simulation model is established using FlexSim, where six experiments were carried out considering 120, 140, 160, 180, 200, and 220 AGVs evenly distributed among operators. The experimental results show that the number of AGVs has a significant effect on the system throughput. More specifically, the system throughput increases as the number of AGVs increases initially. However, after a certain point, the increase in the number of AGVs will cause a decrease in system throughput, and this is due to congestion, collision, and lack of space. The outcome of this research provides useful insights for AGV sorting system application in CFP systems.