Rehrig Pacific Co. (Los Angeles, CA), a manufacturer of plastic crates and pallets for the food and beverage and environmental industries, is on a mission to automate operations in and around its factory. While the company, which has seven plants nationwide, has a long way to go before it's considered a "lights out" operation, it is slowly testing the waters with robot technology deemed to be a safe bet.
Mauricio Cavalcante, a senior plant engineer at Rehrig's Lawrenceville, GA, plant, recently installed a transportation robot-otherwise known as an automatic (or automated) guided vehicle, or AGV-to move stacks of containers between the machine room and the warehouse. The forklift-style AGV that Cavalcante oversees, which went live in November, is from AGV Products Inc. (Charlotte, NC). The result? "We are saving money and the plant is much safer," he says.
Indeed, AGV systems have come a long way over the years, evolving from complex proprietary and inflexible wire-based systems to wireless systems that feature a broader range of movement and have easy-to-use graphical interfaces. The wireless AGVs use two different types of navigation technology: laser or inertial. The primary difference is that laser-guided vehicles operate based on line-of-sight, using reflectors on walls to determine position. Inertial, on the other hand, relies on an electronic gyroscope and magnets embedded in the floor for direction (see sidebar).
The choice of which wireless navigation technology to use often comes down to the application. Companies that have low height-lifting needs often standardize on inertial, because it is floor-based; if a forklift-style machine is required, laser is often the pick. Both work fine, say industry observers, but what's most notable are developments in mapping software and line-of-sight flexibility in mobile robots from the likes of AGV Products, Transbotics Corp. (Charlotte, NC), and Siemens Dematic AG (Nuremberg, Germany), to name a few. "If you use inertial or laser-based, it doesn't matter," says Don Holdenrid, director of sales and marketing at AGV Products. "But now it is easier for the end user to go into a system and change a path with a point and click."
Until now, manufacturers have had to rely heavily upon AGV vendors, because even the slightest change to the transportation path required the expensive engineering prowess of the supplier. In an attempt to change that equation, earlier this year AGV Products partnered with Nuova Fima (Invorio, Italy) to develop a new package for its laser-guided vehicles. It includes an on-board PC that can calculate complex routing configurations and Windows-based graphics that allow end users to change the program themselves. "We are focused on customer relationships and being able to provide a reliable system that the end user can control," says Holdenrid.
Similarly, Siemens Dematic created a Windows-based engineering tool called Q-CAN for its inertial AGVs. The tool enables a user to re-draw and re-define the system without needing to know the system's software or CAD application. An end user can map the system and create system logic using simple dialog boxes and drawing tools in a model that is downloaded to the AGV. "In an engineered system the only way to see the model before putting it in is to pay $10,000 for a computer simulation," says Garry Koff, AGV technology manager at Siemens Dematic's Material Handling Automation Division (Grand Rapids, MI). "Now they pay zero."
Siemens Dematic is counting on Q-CAN to expand the AGV market, which is very small. Only about 70 systems are sold per year in the market as a whole, notes Koff. Why? AGVs are pricey; they range between $30,000 to hundreds of thousands of dollars depending upon the size and configuration of the mobile robot and system software. But the real expense comes from having to call in the vendor for every minor tweak to the system software. Plus, AGVs have been perceived as too high-tech for many facilities. "If we make it less expensive, less complicated, and easier to understandthat lowers the anxiety level," Koff says.
Once those benefits are articulated to end users and the systems are moved into a manufacturing or warehouse site, the AGVs prove themselves. At Rehrig Pacific, the AGV in use has eliminated the need for a forklift driver and reduced the risk of accidents. "The AGV has not made the operation faster, but it has become more structured," Cavalcante says. It is safer not only because things must be better organized for the transportation robot, but the laser-guided vehicle will stop if something obstructs its line-of-sight to the reflector on the wall, thereby avoiding an accident in the event a person walks in front of its path, for example.
The laser reflectors are typically installed about 25 feet away from the AGV. The area must be surveyed first to strategically position the hundreds of reflectors, at a cost of about $20 each, lining the walls to direct a robot. But recently, there have been advances in this area to make AGVs even more flexible and reduce the number of reflectors required. Transbotics recently introduced round reflectors (which contrast with the traditional rectangular tape-like reflector) that allow the system to ride down an aisle for up to 100 feet without any reflector on either side of it. This is significant because "if you have a warehouse with a lot of aisles, you'd need to mount hundreds and hundreds of reflectors," says Tommy Hessler, Transbotics executive vice president. The round reflectors cut that amount substantially, which lowers the cost of the deployment and increases the flexibility of the AGV.
Furthermore, the Transbotics system is capable of moving sideways, not just back and forth, because it includes two sets of wheels for quad movement. Transbotics, which was formerly called NDC Automation Inc., specializes in turnkey laser-guided vehicles. The company builds each system specifically to the customer's needs. While they will design a wired system, 85% of what the company sells is laser-based, notes Hessler.
So it's no surprise that ABB Group (Zurich, Switzerland) deals only with laser-guided systems. ABB entered the AGV market last year by partnering with Danaher Motion Saro AB (Saro, Sweden)-formerly named NDC Automation AB. There are clear advantages to the laser technology. "It is easy to install, easy to program and get up and running, and you can integrate the [Danaher] equipment on to a traditional forklift," says Mike Crane, segment driver for consumer industry products and sales at ABB Robotic Automation Systems (New Berlin, WI). To date, however, ABB has only a handful of customers. The hope is, however, that recent technology advances in this area will catch the eye of other manufacturers that are just now becoming interested in automating warehouse and factory-floor operations.
Still, Cavalcante, who says the laser vehicle from AGV Products is reliable and has met all of his needs, warns that it is not a plug-and-play system. In order to get everything running smoothly, the company had to invest two months of time upfront with the vendor just to survey the site, set up the system, work out the bugs, and make the changes that fit the environment. But the investment in time has been worthwhile. "We had certain goals from the beginning of the project and they've met every one," says Cavalcante. "Any enhancements [to the system] from now on would just be a bonus." MA