Gain Automated, Efficient Material Handling with AGVs and AMRs

The surge in e-commerce since the pandemic has led to a greater need for operational efficiencies, namely through the implementation of material handling automation. Since agility is needed for both fulfillment centers and manufacturing facilities, AGVs and AMRs give promise to replace manual labor in processes that are redundant in nature but can be reprogramed. While there is a host of automation solutions, automated guided vehicles (AGVs) and autonomous mobile robots (AMRs) provide a great deal of efficiency in a small footprint, which can save money but boost throughput rates.

In fact, the demand for AGVs and AMRs is growing globally. According to ResearchandMarkets, the AGV and AMR market is expected to reach $18 billion by 2027, with an install base of 2.4 million robots. The AGV and AMR growth rate during this period will near 24% and 43%, respectfully.

What is driving demand growth? Both ResearchandMarkets and MarketsandMarkets cite a few major reasons AGVs and mobile robots are gaining in importance.

• The avoidance of building costly greenfield facilities by utilizing AGVs and mobile robots for space optimization.
• Worker safety by relying on AGVs and AMRs for potentially dangerous storage and retrieval activities.
• Investment in AVGs by small- and medium-sized businesses to remain competitive against larger market players, leading to improved productivity and efficiency levels — which hopefully results in higher profitability.

A deeper dive into AGVs and AMRs will reveal how these two automated solutions compare and where they provide the most value within an integrated logistics environment.

AGVs and AMRs are the Same … but Different

A common question when discussing AGVs and AMRs is what differentiates the two solutions? Both serve very similar purposes in distribution centers and production facilities — automating materials flows. However, there is a distinct difference in their operation. AGVs are an older technology, but even more important, the vehicles travel along a dedicated path between points throughout the warehouse. A fixed path down aisles and throughout various rooms dictates the destination to pick and assembly areas.

The guidance system for AGVs comes in a couple of forms — laser and magnetic guidance. The vehicle has a laser head and triangulates its position from reflective targets along the vehicle path that ensure its accurate location. With magnetic guidance, rare earth magnets are embedded in the flooring. As the vehicle drives over the magnet, it updates its current position and uses gyro (or gyroscope) to traverse from one point to the next along the magnetic route.

What occurs if there’s an obstruction along the AGV path? Occasionally, a pallet, object, or facility traffic can obstruct the laser or magnetic route. When the AGV approaches and detects the obstruction, it will stop until the path is cleared.

An AMR operates closely to that of an AGV vehicle. However, AMRs are more autonomous and can decipher multiple routes, with the fleet control system choosing the one that’s most efficient based on circumstances within the facility. The system scans and maps walls and other fixed structures to understand the facility environment and can operate freely without reflectors and magnets. Where an AGV must stop at an obstruction, an AMR has the capability to detect the barrier and reroute without interrupting its operation.

Mike Rodriguez, executive sales manager for Schaefer Systems International, Inc., says there's a new type of contour-based guidance system called simultaneous localization and mapping (SLAM) that allows an AGV to operate more like an AMR — a hybrid solution of sorts.

“Contour based works well within a room that has three walls with fixed structures that the system can guide itself. But when you’re in an open warehouse with pallet racking and few fixed structures, you could operate a hybrid AGV using laser guidance in the open warehouse and SLAM within a room where there’s some flexibility,” says Rodriguez. “The lines are blurring between AGVs and AMRs. Traditional AMR guidance is going to be vision-, contour, or LIDAR-based operation, as opposed to fixed locations that rely on laser or magnetic targets.”

Both the AGV and AMR markets are exploding in terms of technological advancements and capabilities. The lines between AGVs and AMRs will continue to converge as capacity, safety devices, and more guidance methods for AGVs evolve.

“In the past, AMRs were restricted to load-style vehicles due to their type of guidance. They weren’t set up well for forklift-style vehicles. And that’s changing,” says Rodriguez. “As technology improves the smart solutions that can be offered by these technologies just get better and better.”

Critical Roles in Distribution Center and Production Facilities

When it comes to which solution to choose in either a DC or production environment, Rodriguez says with AGVs it depends on the class of vehicle being considered. An AGV has the capability to be a full pallet or an even larger load solution, while also serving as an ideal tote-type solution. There is a wide range of load handling units that the vehicle can accommodate.

In a pallet scenario, for example, operators could choose a forklift-style vehicle with the capacity to load a pallet from the floor or a conveyor or racking — similar to a standard forklift. And then transport that pallet to a production area or from production to a work in process (WIP) or finished goods station. Rodriguez says there are other types of pallet handling AGV vehicles, such as lift deck and roller deck vehicles. The solution really depends on the application of what the pick and drop locations look like and the process that the vehicle is achieving. 

With a smaller scale vehicle, it can accommodate totes or bins or cases that are manually or automatically loaded and offloaded at pick and drop locations. These vehicles often transport parts from a pick area to the production line or picking WIP products and delivering them to a WIP buffer area.

Another AGV commonly used within manufacturing is a tugger vehicle. Rodriguez says that in a production-type environment where there is a large amount of material that needs to be transported from the receiving or staging area to production lines, operators will chain or create a train of tugger carts. An AGV then transports those carts to different zones within the production line.

“AMRs can handle many of those types of solutions depending on the free space available within the aisles and the aisle where traffic exists. If you have high throughput demand, then using an AGV makes sense because you have more fixed paths and dedicated aisles or lanes that vehicle can travel within. There’s more reliability on meeting those throughputs,” Rodriguez explains. “With an AMR, there’s more flexibility in the path that vehicle can take. However, that flexibility makes it more difficult to know if it’s 10 minutes between point A and point B due to how the vehicle is routed to the location. This could be a major consideration when choosing an AGV versus an AMR.”

In a production environment, an AMR is more flexible in how it achieves the picking and put-away process, but it is also perceived more as a cobot or inter-relational space sharing solution with other humans or equipment, says Rodriguez. When people look at AMRs, it’s the cobot-style operating ability where the solution can cohabitate easily with humans that is appealing.

“However, I’m dubious of how effective that it in today’s world. AGVs could do similar things and work within that space as well,” says Rodriguez. “Neither solution works well with forklift traffic. We try to avoid interactions between regular fork-truck traffic and AGVs and AMRs because they follow fairly defined paths and navigate intersections in a certain way. These are expensive pieces of equipment, so we try to segregate AGVs and AMRs from fork trucks to prevent collisions and costly damage.”

Keys to Implementation and System Integration

Knowing how AGVs and AMRs navigate their environments, what is the ease in their overall implementation and system integration? Rodriguez says a benefit of AMRs is their intuitive systems and lack of fixed external reference points, such as laser and magnetic targets. Simply place the AMR on the facility floor and allow it to travel throughout the environment to map it. Once the mapping exercise is complete, the AMR returns to the fleet controller and communicates the mapping to the other AMR fleet vehicles.

The implementation process for AGVs is more involved because they lack the full-scale self-learning capabilities of AMRs. However, as technology has evolved, AGVs are closer to that level of intuitiveness, says Rodriguez. Because AGVs have a defined path, there are circumstances where paths in the facility are restricted to only AGVs or forklifts or people. Depending on what operators want to achieve in their facility, an AGV solution may be more restrictive to ensure the AGVs have a clear and short path from point A to point B.

“Both systems have a fleet controller, which is the mother brain for the entire system. The fleet controller knows the precise location of all the vehicles in the system, providing traffic management control and routing instructions for those vehicles,” says Rodriguez. “The fleet controller also interfaces with the host warehouse management system or warehouse control system software. In a typical environment, there are pick and drop locations. Through an interface with the host, the fleet system knows when there’s a load ready for pick up and communication with the robotic cell occurs to ensure clean and safe transport of the AGV vehicle to pick up the pallet.”

Get Started with AGV and AMR Solutions

Ready to make the investment in an AGV or AMR automated solution? Rodriguez says first and foremost, when working with a vendor like SSI SCHAEFFER, the first critical steps are working through identifying the current processes within the facility, the application needs, and the ultimate goals of process automation. What is the best technology to meet those needs or possible alternatives to technology.

“It comes down to really understanding the need. Do you need to pick up loads from the floor or are they coming off a conveyor or racking? Do you want to go 15-foot high and rack? Those questions can lead to what’s the best vehicle type for the application,” Rodriguez explains.

“Similarly, what's the best battery type for powering the system? This leads into questions about how many hours per day is the system running? What type of throughput is required? That will narrow down the best type of battery technology for that application. All critical and essential questions to meeting the customer need.”

SSI SCHAEFER provides both solutions and a material handling expert is happy to discuss your application. Feel free to complete the contact form and we’ll get started.