Leave the (forklift) driving to us?

Cruise the aisles of a material handling trade show and you can't help but notice that robots are everywhere. At a time when improving productivity is the top priority, warehouses and DCs are trying to automate every activity they can—including, of course, the transport of pallets and cases.

Automated guided vehicles (AGVs) that move pallets and cases have been around for years. But their high cost and limited flexibility have made them more popular in manufacturing plants than in warehouses, where lift trucks rule the roost. Now, a new type of equipment is bridging the gap between the two: automated, or "driverless," forklifts and pallet trucks.

Automated lift trucks are used in a variety of ways. Some meet up with workers who are picking orders in the aisles and travel alongside, moving from one pick or putaway location to the next automatically or as directed by their human companions. When the case pick is completed or the pallet is full, the vehicle delivers its load to a designated location, such as a conveyor or staging area. Some carry an operator but move from place to place on their own. Others pick and put away pallets entirely on their own, with no operator involved. All boost productivity by reducing the amount of time warehouse workers spend searching for pick and putaway locations, walking and driving, and stepping on and off vehicles.

Automated industrial trucks have been available in Europe, Asia, and Australia/New Zealand for several years now. But driverless vehicles are still new to North America. Although vendors say the trucks offer double-digit productivity improvements, warehouse operators aren't rushing to buy yet. Before they invest in new technology, potential buyers want to know whether the productivity benefits make automated trucks a "must have" or if this is just another example of a "gee whiz" technology in search of an application.

What they do and how they do it
To get a handle on the potential benefits of automated forklifts and pallet trucks, it helps to compare them with AGVs. The line between them is an increasingly blurry one, especially as AGV manufacturers increase flexibility and slash their machines' prices. But in general, AGVs are designed to repetitively transport items along a fixed path. The vehicles usually are guided by tape, laser reflectors, wires, or magnets located on a facility's floor, and they typically have no operator compartment. They can be switched to manual mode, but this can take a little time and the AGV must be moved out of the guide path. Depending on the application, they may or may not have forks.

One thing automated forklifts and pallet trucks have in common with AGVs is that they must comply with the same industry-approved safety standards. In addition to audible warnings and lights, they have built-in sensors to detect obstructions and determine whether and when to slow down or stop to prevent a collision. The sensors, which may include lasers and camera systems, are positioned so they can detect objects and activity from the floor to specified heights and distances around the vehicle.

A key difference is that automated trucks offer more variety. While most are electric, they come in a range of models, including pallet trucks, counterbalanced sit-down and stand-up forklifts, order pickers, turret trucks, and reach trucks. They also use a variety of guidance systems, including lasers, vision-based guidance, radio-frequency identification (RFID), and global positioning systems (GPS). In some cases, a single vehicle can operate with multiple navigation technologies. For example, Kollmorgen, which provides "automation kits" for AGVs and fork trucks, says its NDC8 control system works with all established navigation technologies, allowing a vehicle to, say, serve a storage area using one type of navigation and a manufacturing area using another. Regardless of the navigation method, however, there must be an overlaying system that controls and directs the entire fleet of automated lift trucks to ensure safe, efficient operation, says Tomas Angervall, product marketing manager for Kollmorgen.

Collaboration among truck makers and specialists in vehicle control systems is common. In Europe, for example, some Toyota Material Handling Europe (TMHE) and Jungheinrich products use Kollmorgen's NDC8 control system, while Linde Material Handling collaborates with Seegrid Corp., the developer of vision-guided AGVs. In the North American market, meanwhile, Mitsubishi Caterpillar Forklift America Inc. (MCFA) is working with Egemin Automation on a laser-guided, stand-up, counterbalanced forklift. The Raymond Corp. has partnered with Seegrid, and Crown Equipment Corp. supplies forklifts for Dematic's LaserTrucks+ voice-directed case-pick system. Nissan Forklift Corp. provides a pallet truck for Swisslog's AGVPick product, which also uses Kollmorgen's laser-guidance controls.

Not all automated trucks involve such collaborations, though. Crown's QuickPick Remote pallet truck is an independent product. So is Jungheinrich's RFID-based Warehouse Navigation semi-automated system for very narrow-aisle trucks, which is distributed through MCFA's dealer network in North America. (See sidebar for a list of automated truck providers.)

Some automated trucks are directed to the proper location by the operator. Depending on the guidance system and provider, this is accomplished by speaking into a voice system, using a remote control, or by responding to operators' movements telegraphed by a band they wear around their wrist.

Others are directed by a warehouse management system (WMS) in concert with the traffic control system. Integrating with a WMS can help solve problems like excessive travel time and exactly match actions to orders, say vendors. "If total flexibility is required due to highly dynamic warehouse processes, then not connecting may be best," says Brian McCahill, Kollmorgen's business unit director, AGV Systems North America. "But if you have a pretty stable picking process and if your WMS is already talking to a voice system, why not have the [vehicle] get that same information at the same time to take full advantage of the available productivity gains?"

Unlike traditional AGVs, automated trucks aren't limited to set routes; they can go anywhere a warehouse worker would go. They can also quickly change from automatic to manual mode with the flip of a switch. This lets the buyer define the most efficient way to operate for a particular pick cycle or environment, says William Pfleger, president of Yale Materials Handling Corp. For example, if pick locations are close together, the operator could continue to pick while moving the truck remotely. But if there are long distances between picks, the operator could save time by switching to manual mode and driving at the maximum speed to the next location, he explains.

It won't always be obvious to the operator which mode would be most efficient, though. Here's where interfacing with a WMS and voice system can help. "We use the software to tell the drivers through the voice system when they should ride the vehicle and when they should pick with it in the automatic mode," says Brad Moore, vice president, AGVPick and global accounts for Swisslog.

Some automated systems will even determine when and how high to raise and lower the lift truck's mast. To maintain stability, most operators fully lower the mast and drive at full speed, then lift again on reaching the pick location. But that's not necessarily the most efficient way to go, says Michael Wiesenegg, product line manager - warehouse systems, for MCFA. Depending on the distance between picks and their rack levels, it may be faster and more efficient to drive with the mast partially raised. "The truck knows how low you have to go to find the best combination of driving speed and lifting," he says.

Payback in productivity
While the sight of a forklift driving itself around a warehouse is bound to impress, technological wizardry isn't reason enough to invest in new equipment. There must be solid productivity and cost benefits. In the right environment, say providers, automated trucks definitely deliver.

What's the right environment? Vendors are targeting case pick-to-pallet operations, especially those with a high-wage workforce and/or where labor is in short supply. In addition, "any warehouse of 200,000 square feet or more, with lots of repetitive, horizontal travel with full pallets or carts over long distances, with multiple shifts, and putaway requirements for moving large numbers of pallets quickly is a good candidate," says Frank Devlin, marketing manager, advanced technologies for The Raymond Corp. "If you're running more or less the same routes with a pretty regular stream of products from one end of a building to another and have to deadhead back, that's the ideal place for automated lift trucks."

The biggest payback comes in productivity improvements. The use of automated trucks to eliminate pre- and post-picking activities like retrieving empty pallets and moving full pallets to stretch wrappers and loading docks boosts time spent on picking to 80 percent, by some estimates. Moore suggests thinking of automated trucks as combining the best aspects of pick-to-belt and pick-to-pallet. "With pick-to-belt, generally there are two touches: someone picking product and placing it on the belt conveyor, and another at the end of the line building the pallet and driving it around. With AGVPick, the AGV is doing the work of the conveyor belt by moving the product. So instead of two touches, we have only one."

When the WMS sends semi-automated trucks to the required positions, operators don't spend time searching for pick or putaway locations. This can shave five to eight seconds off each pick on average, says Wiesenegg. That's especially beneficial for DCs that hire seasonal or temporary help, he says, adding that for one customer, Jungheinrich's Warehouse Navigation system boosted productivity by 10 to 15 percent "just through eliminating the experience factor."

In fact, the technology may help any new employee become proficient more quickly, says Tim Quellhorst, senior vice president, Crown Equipment Corp. Furthermore, workers who have used his company's automated solutions report that they are not as tired at the end of a shift even though they are doing more work, he says. "Even semi-automation made their jobs less of a mental challenge and less physically demanding," Quellhorst adds. "That can increase productivity and improve retention and job satisfaction."

Cost advantages
There's a cost associated with automating forklifts and pallet trucks, of course. But according to Yale's Pfleger, all of the prospective buyers he's spoken with are focusing on overall ROI rather than on purchase price. He believes that for many warehouses and DCs, the productivity improvements from automation would more than offset any additional costs over manual lift trucks.

But there are also some cost advantages in comparison to AGVs. Because automated trucks are based on mass-produced equipment, manufacturers can keep the price down—to about two-thirds the cost of a comparable AGV, by most estimates. A fully automated machine reduces the number of personnel required and can operate in low light and temperatures, saving on energy costs. Some vendors also contend that automated trucks do less damage to goods, infrastructure, and themselves than drivers on manual trucks do.

Furthermore, it takes little time and little or no additional infrastructure to introduce automated trucks, says Raymond's Devlin. No major renovations or installations are required, whereas a traditional AGV system could require several months of planning, engineering, software programming, installation, and testing, he asserts. And it's easier for free-ranging trucks to accommodate changing warehouse layouts than it is for most AGV systems.

Be realistic
Any new technology, no matter how great its potential, is bound to raise some concerns. Quellhorst, for one, cautions that driverless forklifts and pallet trucks are not yet equivalent to conventional equipment. Because of speed and performance requirements, he notes, manual trucks have to withstand a lot of vibration and other physical demands. Automated trucks are not as robust, in his view. "When I think of a true dual-mode solution—a forklift that can work in automatic mode just as well as in manual—I think that day isn't here yet, and that more work is needed to develop the technology so it can stand up to the demands that are placed on manual vehicles," he observes.

Additionally, potential buyers should not be lulled into thinking that introducing automated trucks is as easy as sending new manual ones out on the floor. "You're not just adding forklifts," says Wiesenegg. "It's an integration of systems, and you have to make sure the software is complementary and that the implementation goes smoothly." Much depends on how well organized the facility is and how effectively it uses its WMS, he adds. "The more organized you are, the better you can program an automated system and benefit from it. ... If you are not well organized and you go to a fully automated system, it can do a lot of damage."

DC managers may be slow to accept automated forklifts and pallet trucks for fear of disrupting operations, and some may be skeptical of technology that may look more like a science project than a practical solution. But automated trucks could fill a need for companies that are trying to figure out how to handle rebounding business but are wary of adding a lot of labor in a still-sluggish economy. It's also an attractive technology for warehouses that have difficulty finding enough qualified workers—still a common problem despite the high unemployment rate.

More importantly, the double-digit productivity gains in picking, putaway, and travel time claimed by the manufacturers—from 20 percent to 50 percent, depending on the activity—are hard to ignore. In the right circumstances, this technology could help warehouses and DCs achieve their most important goals: improving productivity and keeping labor costs under control.