AMRs and AGVs: Two Automated Guided Vehicle Systems, Compared

Automated guided vehicles (AGVs) and autonomous mobile robots (AMRs) have one task: to transport materials in a warehouse from one location to another. But that’s all the two types of automated guided vehicle systems have in common as these two systems could not be any more different in design. Read on to learn about:

• The differences between AGVs and AMRs
• The pros and cons of both systems
• The costs of AGVs and AMRs

For many years, AGVs were the only option for automating internal transport tasks. They came into use in the 1950s and 60s and quickly took over physically demanding, monotonous and repetitive tasks and material flows.

As the industry developed and the demand for mass customization grew, so did the demand for more flexibility and scalability in transport systems. Flexibility requires intelligent systems and the first autonomous mobile robots entered the market in the 2010s. AGVs and AMRs have been a part of everyday life in logistics for years, but explaining the difference between them remains a challenge. Let’s start by defining both terms before we explore the differences.

The biggest difference between AGVs and AMRs is in how the systems navigate. AGVs transport goods on set routes and cannot deviate from them. They orient themselves using artificial landmarks such as wires, magnetic strips, optical markers or reflectors that allow them to localize. This makes planning transport routes very labor-intensive and frequently requires modifications to the warehouse.

AMRs, on the other hand, move autonomously. They navigate using maps that are either uploaded to the AMR or are produced by the AMR itself. Cameras, sensors, laser scanners and intelligent software allow AMRs to automatically calculate the shortest route to their destination while adapting to the information they receive in real time.

Thanks to their technologies, both AGVs and AMRs are completely safe to use in warehouses. Both systems have safety scanners and are often also equipped with cameras and numerous other sensors.

What makes them different is how each system handles obstacles. AGVs stop when an obstacle blocks their path and waits for the path to be cleared, while AMRs drive around obstacles before finding a new path to their destination thanks to their artificial intelligence.

AMRs’ ability to navigate, paired with their intelligent software, means they place very few demands on their environment. They can be integrated into internal transport processes quickly and without any need for construction or modifications, even during on-going operation. They don’t need much space to perform their transport tasks and can even navigate very narrow passages.

AGVs, however, are a different story. Planning the route network requires a lot of work and additional construction often has to be performed in the building, which means installation can only be done if operation is interrupted.

Thanks to their autonomy, AMRs are much more flexible than AGVs, which travel on fixed paths. The paths and fleet size of AGVs are difficult to change without additional construction.

AMRs, on the other hand, adapt their routes and processes using intelligent software. The fleet size can also be changed as required, such as to cover peaks or react to changes in the market.

The tasks carried out and paths taken by AGVs are very simple and straightforward. Transports are always carried out the same way, travel paths don’t change and the vehicle stops if an obstacle is in the way. These factors means that AGVs are very predictable; their actions are plannable. They are punctual and highly efficient in performing their transport tasks.

Meanwhile, AMRs’ travel paths are often harder to predict. Their autonomy means people cannot predict how they will go around obstacles or what new route they are planning. As far as predictability is concerned, AGVs definitely have the upper hand.

Originally, AMRs were used to transport lighter loads, while AGVs transported pallets. Today, their areas of application hardly differ at all. Both automated guided vehicle systems perform a variety of internal transport tasks. The most frequent uses include supplying work stations and production lines, supporting the picking process and providing connection to conveyor systems or automated storage systems.

Both AGVs and AMRs can be adapted to meet the customer’s needs. Autonomous mobile robots have also experienced tremendous development in the past few years.  The intelligent transport robots can even transport pallets, as our Open Shuttle Fork shows. Here you can see our solution for internal pallet transport in action at Fronius.

Which automated transport system is more cost-efficient? At first glance, the acquisition costs of AGVs are often lower than those of AMRs, which are more expensive due to their intelligence and complex sensors. However, once the costs of modifying the warehouse to accommodate the AGVs are taken into account, including the more complicated planning and commissioning, costs are frequently higher.

In addition, startup often requires production to be stopped if the AGVs are not being built into a new system. These interruptions can be costly. AMRs, on the other hand, can be implemented quickly and increase efficiency immediately. Later changes made to an AMR system are also much faster and easier to carry out.

Are you now wondering which criteria need to be taken into account when choosing an automated guided vehicle system? The following questions are decisive when deciding between AGVs and AMRs:

• Which transport tasks does the system need to perform?
• Does the system need to be changeable and scalable?
• Are goods flows constant or highly dynamic?

If travel paths remain the same, if material flows are constant and if there is a low number of obstacles, AGVs are preferable. They are lower-cost and perform all their tasks precisely and reliably. However, if paths and transport tasks vary, AMRs are definitely the better choice.

And change is a fact of life, especially in today’s market. We’re all struggling with decreasing plannability, the shortage of qualified personnel and resource shortages. As a result, it’s of utmost importance that today’s automated guided vehicle systems are fast to integrate and adapt. A modern production environment should not make itself dependent on inflexible technology. In short, AMRs are superior to AGVs in terms of flexibility, scalability, installation time and profitability.

However, planning a complete automation solution is much more than just deciding between AGVs and AMRs. They’re often part of a hybrid solution consisting of a mixture of automated guided vehicle systems, manual and automated conveyor systems, state-of-the-art picking systems and mixed traffic. And of course, an automation solution cannot succeed without its key component – intelligent software. To see how a complete automation solution might look like in practice, check out our case study on Magna Assamstadt.

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