Automated Guided Vehicles (AGVs) are popular automated solutions for transporting materials in warehouses, distribution centers and manufacturing plants. Some of the many benefits of AGVs include reduced labor cost, reduced damage to products, increased warehouse safety, and the relatively lower cost than some other more complicated automated systems. Plus, most AGVs can be implemented without any new infrastructure, providing less disruption to the current operation.

When seeking AGV solutions, it can be a challenge to determine AGV count and validate the design. Questions arise that need workable solutions. Will the proposed route cause some congestion? Does it make sense for AGVs to travel that far to do pick-ups and drop-offs? What is the bottleneck in the system? At this point, simulation is a powerful tool in validating AGV model design and AGV count. The consultants at Bastian Solutions use FlexSim simulation software to help clients answer these questions and improve their AGV designs.

Validating AGV Design

Before committing to a specific AGV design, it is imperative to test through simulation if the design can work as expected. Simulation provides useful insights on:

• Whether the design can meet the required rate with the projected growth to the design year.
• What is the system’s maximum capacity?
• Is there any bottleneck in the layout design? If so, how does it affect the system performance?
• How will AGVs interact with other functional areas in the facility?

For example, in the image below, we can see that the path on the left of the picture is very crowded. Six pick-up and drop-off locations are placed close together, causing some congestion on the route and blocking AGVs behind. We can track the number of pallets at certain pick-up locations waiting to be picked up, the number of AGVs blocked, and how frequently they are blocked during the simulation run. Through the visual representation and statistics, conclusions such as whether the design has room for improvement or how much space should be planned at certain area can be reached.

Determining AGV Count

In FlexSim, robust experiments can be conducted to vary model parameters, including changing the number of AGVs running in the model. The chart below shows 21 different experiments using 15 to 35 AGVs in the system. The x axis represents the number of AGVs and y axis represents the total pallets per hour across different functional areas. We can clearly see the diminishing return as we increase the number of AGVs. The trend is going up from 15 AGVs to 25 AGVs and after that the growth is not significant and will eventually cause congestion, without benefits to the overall performance. In this instance, if the rates can be met by 25 AGVs, purchasing more than 25 AGVs cannot be justified.

Other Performance Indicators

Besides chart one showed in the previous session, several additional charts can be generated in FlexSim as needed to further analyze AGV system performance. For example, chart two shows AGV Utilization, including percent of time AGVs are blocked, travel empty, travel loaded, and charging. From this chart, we can have a better understanding of AGV activities.

Learn More

Simulation software like FlexSim offers valuable insights to AGV design that allows for the best and most desirable results. Contact us to learn more about AGV simulation and how it can benefit your operation.

Author: Jiayao Zhang