Similarities and Differences of Mobile Warehouse Transports

Autonomous Mobile Robots (AMR) and Automated Guided Vehicles (AGV) are two of the most well-known mobile warehouse transports in today’s distribution industry. To put it simply:

Autonomous vs Automated
Mobile vs Guided
Robot vs Vehicle
AMR vs AGV

What are Automated Guided Vehicles (AGV)?

Automated Guided Vehicles or AGVs, are a well-known technology used to automate material movement and logistics in highly structured, monolithic and static environments. Introduced in the 1950s by Barrett Electronics, AGVs haul or tow objects that are used in various industries as a material transportation tool. Operating for decades, AGVs ferry goods throughout a facility without human assistance along a fixed and guided route — electric wire buried in the concrete floor, lines of magnets, tape, beacons, or reflectors. The main limitation on these vehicles is that changing that path — to accommodate a new product, client, facility, or a reconfigured workflow — can be time-consuming and expensive.

What are Autonomous Mobile Robots (AMR)?

Autonomous Mobile Robots or AMRs, are a self-guided transport outfitted with software and intelligent sensors that enable it to understand its operating environment and to work collaboratively with humans. The onboard navigation system is what sets the new self-driving warehouse transports apart from their predecessors. Rather than being restricted to fixed routes, AMRs use sensors and processors to perform complex tasks such as simultaneous location and mapping (SLAM). AMRs “learn” their way around a new site avoiding people, cars, forklifts, etc. They rely on artificial intelligence (AI) to sense and respond to the changing environment, optimizing their routes.

Some AMRs can also leverage “swarm intelligence,” which means they can exchange information through wireless networks and change their operations depending on what they learn. This allows the “swarmed” AMRs to adjust their routes based on data that other units have obtained and transmitted. This is a key benefit of these models and some next-gen AGVs—one that conventional AGVs cannot match.

Similarities of AGV and AMR

AGVs and AMRs both carry out the same basic task of moving product or materials from one site to another within a distribution center or other facility. Because this is a low-skill task that does not add a lot of value to an operation, using AGVs and/or AMRs in this way can enable an operation to increase efficiency and productivity while simultaneously reducing labor costs. The tech can also aid operations that are facing a labor shortage or tightening labor market.

It is also possible to implement both AGVs and AMRs on a modular, unit-by-unit basis. This eases the initial up-front capital requirements, helping an operation avoid tying up too much capital in their original automation investment, allowing the use of that capital for other projects while expanding their fleet at a later date.

Differences of AGV and AMR

In determining the difference between AGV and AMR, it’s easy to look at both technologies and view them as robotic transports that move items from place to place. However, it’s important to note the primary shortcomings of the older AGV technology: high cost, inefficiency, and limited flexibility. AMRs are based on new technologies making them faster, smarter, and more efficient. The most fundamental difference between the two comes down to accessing your distribution center’s needs and which technology works best with the layout of your building.

  1. Start Up Cost and Adaptability

It can be difficult to compare AGVs and AMRs on cost alone, as the cost will ultimately depend on a number of factors, from the supplier you work with to the model you choose. It is possible to make a few generalizations. In some cases, AGVs can typically be up to 40% more expensive than AMRs.

As discussed above, AGVs follow fixed routes on tracks, wires, tape, and reflectors to navigate through the facility. Installing these routes require a physical change to the infrastructure of a distribution center, as well as making changes to a delivery route later on can incur added costs. AMRs use digital dynamic maps and utilize on-board camera and laser-based navigational systems. These AMR characteristics enable a quick and reliable configuration and mapping of the robots, saving you time and money. As your business grows, AMRs can be reprogrammed with ease; simply change the route on the digital map.

  1. Size and Maneuverability

AGVs historically have been built larger and heavier in the physical form of automated lift trucks, and have been applied to similar tasks that handle much larger loads than AMRs. This reality makes AGVs more expensive purely from a material’s perspective, whereas AMRs have been built for tasks that require less heavy-duty capability and are able to maneuver facilities with small footprints and narrow aisles with more ease than AGVs.

The primary goal of AGVs is to transport product from one location to another and are best suited to work independently of human operators. Most are simply too bulky and rigid to work in a collaborative setting. Nearly all AGV systems are intended to operate with and away from individuals without obstructions. AGVs are secure in that when an obstacle is identified they will stop, but will remain idle until that obstacle is removed.

AMRs, on the other hand, are collaborative. Their sophisticated sensors and relatively compact size make them safe enough to operate in the same floor space as laborers. They are able to deliver directly to the point of use and travel the same routes with pedestrian foot traffic. If an obstacle is identified and the robot has enough space to move around it, an AMR will adapt its path and maintain the delivery route.

  1. Flexible Delivery and Intelligent Navigation

AGVs are limited to following a strict guidance system that is integrated into the facility with minimal on-board intelligence. This constrains the distributor into establishing specific paths with fixed drop-off or pick-up points. AGVs function independently, must be manually programmed to avoid each other, and obey simple programming instructions. While delivering materials, AGVs can detect obstacles in front of them, but do not have the capability to make quick detours, remaining immobile until the obstacle is removed. This leads to expensive upgrades down the road as your facility changes and puts you at risk for more work-related accidents to occur. AGVs may be better suited for operations that do not experience much change—mature businesses following a traditional business model.

AMRs are far more flexible from the mapping software used to determine the most ideal delivery or pickup route. The same robot can conduct a range of tasks at different locations, adapting to altering environments automatically. For example, if inventory racks are moved or new racks are added, the AMR only needs a simple software adjustment to reflect the distribution center’s new layout or the updated layout can be re-mapped onsite. The AMR uses data from cameras, built-in sensors, and laser scanners to detect its surroundings to choose the most efficient route to the target. It operates entirely independently and if there are forklifts, pallets, individuals, or other obstructions in front of it, the AMR will maneuver around them safely. Additionally, a fleet of AMRs at a single distribution center can communicate with each other, via the robot’s interface, maximizing traffic flow, avoiding collisions and jams, and automatically prioritizing orders to the robot that is best-suited for a given task. Once a task is issued, employees do not have to spend time coordinating the robots’ work, allowing them to focus on value-add work that contributes to company success. This reality typically makes AMRs a better choice for younger, more agile businesses that regularly experience change.

Source: Aethon.com

The most important difference when discussing AMRs vs. AGVs is that AGV technology represents an earlier generation of automation that simply can’t keep up with the flexibility and cost-effectiveness of AMRs. The future of the distribution industry is built with flexibility, automation and connectivity in mind. When the product mix or manufacturing process needs to change, today’s distributors must be able to adapt and change with the demands of the market. Your flexibility will be significantly reduced if your internal transportation is fixed in the paths or fixed in its capability. As distributors look for ways to profitably compete in an increasingly volatile business environment that rewards flexibility and effectiveness, it is essential to choose technology that provides flexibility in real-time — whether the modifications happen in the short-term or over several years.

Fun Facts

According to IDC’s 2018 Autonomous Mobile Robots in the Warehouse and Fulfillment Center Maturity Scape Benchmark Survey,

  • 47.2% of users were at the “ad hoc” level of AMR adoption, running only sporadic/pilot programs,
  • 33.8% were at the “repeatable” stage, where they’re just beginning to expand their deployments,
  • 15.2% at the “managed” stage of maturity, where they’re achieving competitive advantage,
  • 3.8% at the fully “optimized” stage of widespread adoption of AMRs, IDC found.

By contrast, AGVs are rooted in many U.S. logistics centers, with operations running for decades. Companies introducing AMRs into their operations will most likely use them in combination with AGVs and other automated equipment. When it comes to vehicle choice, it may not necessarily be an “either-or” question. Each has their own benefits. The key challenge for the decision-maker is to pick the right combination of robotic technology for the problem they’re trying to solve.

Sources:
Melanson, Tony. “AGVs vs. AMRs: What’s the Difference?.” Aethon, ST Engineering Aethon, Inc.,  https://aethon.com/agv-vs-amr-whats-the-difference/
Ames, Ben. “AMRs and AGVs rev their engines.” DC Velocity, Agile Business Media, LLC., 30 November 2018, https://www.dcvelocity.com/articles/20181130-amrs-and-agvs-rev-their-engines/
Lodwig, David. “AMRs vs AGVs: System Comparison.” Conveyco, Conveco Technologies, Published: 17 December 2018, Updated: 20 June 2019, https://www.conveyco.com/amrs-vs-agvs/
“AGV vs AMR. Who is the winner?”. Types of AGV, AGV Network, 20 September 2019, http://www.agvnetwork.com/automated-guided-vehicles-technology/types-of-agv/agv-vs-amr-who-is-the-winner
“AMRs vs. AGVs: The Difference Between a Robot and a Guided Vehicle.” Fetch Robotics, Inc., https://fetchrobotics.com/fetch-robotics-blog/amrs-vs-agvs-whats-the-difference/
“AGV vs. AMR – What’s the Difference?” MIR, Mobile Industrial Robots A/S, https://www.mobile-industrial-robots.com/en/resources/whitepapers/agv-vs-amr-whats-the-difference/

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