If you were at ProMat or Modex about 10 years ago, you may have stopped by a booth where Egemin and MFC Cat, now part of Mitsubishi Logisnext Americas, were exhibiting a hybrid lift truck. Turn the key to the left, and a driver could operate it like any other lift truck; turn the key to the right, and the lift truck operated autonomously like an automatic guided vehicle (AGV), using technology from Egemin. Or something like that.

The vehicle had a number of things going for it. For one, it promised labor savings by reducing the number of lift truck drivers a facility might need, while also offering flexibility if another truck needed to be pressed into service during a busy period.

For another, AGVs are typically purpose built to solve specific problems in a specific facility. The lift truck in the booth came off the assembly line, like any other lift truck. Mass production is always more affordable than customization. What’s more, the vehicle could be serviced by an existing network of technicians and dealers.

To many, it seemed like a no brainer. And yet, despite those potential benefits, crickets. Instead, the oxygen in the room was consumed by the introduction of shuttle systems, OPEX and autonomous mobile robots like Kiva. Sure, there was the occasional pilot. Back in May of 2011, Modern wrote about a pilot by of a Yale autonomous lift truck using navigation technology from Balyo by Genco, now part of FedEx. A year later, in October 2012, we profiled how a Toyota auto assembly plant in Kentucky was using autonomous tuggers from Toyota Advanced Logistics to deliver parts to the assembly line. But those really were exceptions. Back then, labor was relatively plentiful, the technology was viewed as too new, and the vehicles, while less expensive than an AGV, were still expensive.

Fast forward a decade, and things may be starting to change. In the last two years, a handful of leading companies have mentioned autonomous mobile lift trucks as part of their technology road map—especially in the 3PL space. Some have even told Modern that they plan to pilot the technology after autonomous mobile robots (AMRs). Developments like those beg two questions: Is the autonomous lift truck about to take off; and, if so, why now?

To the first question, Sylvie Thompson, vice president of consulting for NTT Data, a global consulting firm, says yes, and that “it’s quite impressive how far the technology has come along.” Thompson’s firm worked with one OEM on developing their platform, and has also worked with end users interested in implementing autonomous lift trucks.

In Thompson’s view, the two hurdles to the wide-spread adoption of the technology are perception and “the reality of how we run our facilities on a day-to-day basis,” Thompson says. “Most of our operations and tasks are still designed for human intervention.”

The answer to “why now” is more complex. In any event, following discussions with some of the leading lift truck OEMs, it’s clear that autonomous lift trucks are beginning to gain a foothold, even if this is still an emerging space. Yale, for instance, has deployed “north of 400 robotic reach trucks,” notes Kevin Paramore, Yale’s emerging technology commercialization manager. Yale has also deployed other types of autonomous lift trucks, Paramore says, adding that the OEM “is on the second generation of its autonomous vehicles.”

Why now?

Given all the new technologies on the market today, let’s start with the type of vehicle we’re writing about and what to call it. For the purposes of this story, we’re ignoring fork- and tugger vehicles from AMR providers such as Seegrid and MiR, as well as similar vehicles from AGV suppliers.

Instead, we’re focusing on lift trucks that come off the assembly line and that can operate autonomously, receiving tasks from a warehouse management system (WMS); or, when needed, can be driven by an operator like a conventional lift truck.

The OEMs we spoke to variously referred to them as hybrid lift trucks, autonomous mobile robots, robotic lift trucks and automatic guided vehicles. Since those terms also refer to other types of vehicles in the market, we’re going to call them autonomous lift trucks.

The factors driving the interest in autonomous lift trucks are similar to those behind the boom in robotics and automation in general.

First, and perhaps primary, is the labor shortage, especially in skilled positions like lift truck drivers. “Most companies are struggling to bring in people who can operate equipment,” notes Nathan Augst, director of integration for Toyota Advanced Logistics. With the increase in wages that everyone is experiencing as we come out Covid, it’s easier to achieve an ROI with all types of automation. Perhaps equally important is that these are mass-produced vehicles, just like conventional lift trucks, that can be serviced by an OEMs existing network of dealers and technicians.

Second is the increasing requirement for predictability, stability and flexibility. An autonomous lift truck can deliver on all three, says Tobias Zierhut, head of mobile automation for KION. “With the growth of e-commerce, companies need a reliable and positive flow of transportation,” Zierhut says. “The system always knows where autonomous vehicles are located and what’s on the forks.” That speaks to stability. The ability to operate 24/7 without an operator or to be pressed into service on an as-needed basis as a conventional lift truck speaks to flexibility.

“If your line or operating system goes down, you can still operate the truck in manual mode,” says Toyota Advanced Logistics’ Augst. “That’s a huge reduction in risk for that customer.”

And, don’t underestimate the power of innovation. “If you’re a 3PL, your customers want to know that you’re doing the latest and greatest thing,” points out Jim Gaskell, the director of global automation and emerging technologies for Crown Equipment. Just as 3PLs were the early adopters of AMRs in e-fulfillment operations, they are among the early adopters of autonomous lift trucks.

Finally, As NTT Data’s Thompson says, the technology has made great strides. As with other segments of materials handling automation, that’s the result of lower priced microprocessors, sensors, LIDAR scanners, cameras and computing power, along the adoption of navigation technologies such as natural feature navigation, or geo-guidance, and SLAM that made AMRs possible.

Like AMRs, many of the autonomous lift trucks coming to market have the ability to calculate, and recalculate, the most efficient route to the next task based on real-time conditions encountered on the floor.

Getting to work

Most of the applications in the field today are focused on simple tasks, such as non-value-added travel. Examples might include taking a pallet from the receiving dock to a drop-off location in reserve storage or picking up a pallet in a pick module and delivering it to the shipping dock. Similarly, autonomous tuggers are used in manufacturing for the lineside delivery and pickup of parts and components at workstations on assembly lines. The vehicles might be programmed to handle a number of different routes, but they are repeatable and consistent. “Autonomous lift trucks work well when you have simple, repeatable tasks that don’t need the constant decision-making that an operator needs to do,” says David Norton, vice president of customer solutions and support at Raymond.

The most common application for autonomous lift trucks today is simple, non-value-added travel, such as moving product from a receiving dock or a storage area to another area in a facility.

“When it comes to adoption, we’re still at a place where complexity matters,” adds Thompson. As an example, in the projects that Thompson’s firm has worked on, end users aren’t mixing manual and autonomous operations in the same work zones. “There’s a perception, at least for now, that it’s safer to keep autonomous and manual vehicles separate,” Thompson says. Whether that’s true or not, perception is reality.

Another challenge, she adds, is that the ROI is harder to justify in an existing facility because an investment has already been made in conventional lift trucks and operator training, even if operators are harder and more expensive to come by. “If I was designing a greenfield facility, it would be easier to justify the cost of going autonomous,” Thompson says. “You’re always going to need some human-operated lift trucks, but it could be a cleaner transition.”

Despite those challenges, OEMs are beginning to see some use cases beyond horizontal travel. Raymond stackers, for instance, are used to drop off and pick up loads from conveyors and stretch-wrappers, or to put pallets away on the first level of a rack system.

Crown reach trucks are being used for automatic putaway and retrieval in upper levels of reserve storage rack, and KION has autonomous VNA lift trucks in the field. The lift truck maker has also put them to use in difficult environments, such as freezers. Yale has autonomous lift trucks able to automatically load and unload trailers.

Through integration with a WMS, autonomous lift trucks are capable of task interleaving for greater productivity, adds Yale’s Paramore. He cites the example of a customer that uses autonomous lift trucks to pick up pallets from an automated stretch-wrapper.

“When the WMS sends out a task, it goes to the lift truck that has been waiting the longest between moves,” Paramore says. “The vehicle will know where it’s supposed to deliver that pallet. If that’s the end of the mission, it goes to the back of the line at the stretch-wrapper, but if there is another task nearby, it could do a pallet retrieval from storage.”