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An automated guided vehicle (AGV) is a type of unmanned guided vehicle (UGV) that moves throughout a facility by following a set of predetermined paths. An AGV is not a sub-class of a mobile robot. Instead, AGVs are the predecessors to mobile robots and have been in operation since the 1950s. However, they still have a variety of uses within a modern manufacturing or warehouse environment.

An autonomous mobile robot (AMR) is a di erent class of UGV that has more capabilities than an AGV. AMRs are capable of free-movement and real-time path planning, enabling them to collaborate in material handling tasks with humans.

In addition, while AGVs are all-wheeled vehicles, AMRs come in various locomotion configurations. This includes wheeled vehicles, tracked vehicles, bipedal robots, quadruped robots, and multi-legged robots.

A train versus a taxi

Despite the growing popularity of warehouse automation, confusion remains around the various acronyms and technology. For those in the discovery phase of an automation journey, here’s an overview of two of the most talked about warehouse solutions.

The best analogy for understanding one of the primary di erences between an AGV and an AMR is that an AGV is like a railroad train engine, constrained only to operate on its train tracks. On the other hand, an AMR is like a taxi, able to freely move between any two points and replan a route when tra c is too dense.

The term industrial mobile robot (IMR) was introduced in the recent safety standard ANSI/RIA R15.08. Although it was widely debated by industry experts and voted on within the new standard, IMR has yet to reach broad usage as of the writing of this article but may emerge to replace the term AMR in future years.

In addition to UGVs, there are also unmanned aerial vehicles (drones) and unmanned marine vehicles (autonomous boats or ships).

Warehouse Automation

Similarities between AGVs and AMRs

AGVs and AMRs perform similar functions in different applications. Both types of vehicles can:

• Move material from one point to another within a facility.

• Avoid collisions with objects that might come into their path.

• Operate collaboratively and safely with humans within their workspace or intended paths.

• Carry cargo between 2 kg and 1500 kg.

Differences between AGVs and AMRs

It’s not that one technology is better than the other, but their differences make them useful for specific applications and environments. Such differences include:

Simplicity and cost: AGVs have simpler control systems and sensors than AMRs. In some cases, AGVs are a less expensive solution than AMRs.

Paths and infrastructure: AGVs follow paths along a fixed infrastructure, such as magnetic tape or wire, painted lines, QR code stickers, or laser targets, and they remain within the confines of their lanes or paths. Contrarily, AMRs freely navigate their operational space and between a starting point and a destination. They can also operate outside of a building and follow humans around in a “follow me” application.

Payload: AGVs can be designed to carry extreme payloads, such as locomotive engines and airplane fuselages.

AGVs can be designed as carriers, scissor lifts, forklifts, or other variations and include modules such as box carriers.

| Courtesy of Jungheinrich.

Obstacles: AGVs may become “stuck” if they encounter an object in their intended path. This often requires the help of an operator to move the object and restart the AGV on its mission. AMRs not only avoid obstacles but actively navigate around obstacles to continue toward a mission goal. However, AMRs can become “lost” if they can’t recognize their surroundings. This often occurs when crossing large expanses of floor space without any recognizable infrastructure, such as airplane hangars or large meeting spaces. AMRs can also become lost in repetitive environments, such as similar-looking warehouse aisles or chaotic work areas, such as loading docks. AMR manufacturers have a variety of methods to keep their machines “localized.”

Applications: AGVs work best in welldefined conditions and applications, such as material handling or WIP in a manufacturing facility. AMRs work best for applications in unstructured environments, such as security, deliveries, and person-to-goods and goods-to-person intralogistics.

AMRs are not AGVs

Unfortunately, some AMR manufacturers have adopted the term AGV to describe their autonomous machines. This is unfortunate, as it causes confusion within the market. Remember, the primary requirement of an AGV is that it needs some infrastructure within the vehicle’s workspace to enable navigation and cannot navigate around obstacles. l WH