Toyota Automation: A Tow Tractor Transformation
August 6, 2012Please note this is a summary of an article originally titled “Is there a do it yourself AGV in your future?”, DCVelocity.com
An automation project at a Toyota auto manufacturing plant in Georgetown, Ky., has proven that it’s possible to retrofit some types of manual equipment quickly and easily, earning a big return in terms of cost, labor, efficiency, and flexibility. Although the project involved a manufacturing environment, it may well serve as a prototype for bringing more AGVs to material handling environments, where they have yet to make major inroads due to their cost and complexity.
Toyota Motor Manufacturing Kentucky Inc. (TMMK) makes the Camry, Venza, and Avalon models at the Georgetown facility, a 1,300-acre complex encompassing some 7.5 million square feet of manufacturing and assembly space. Like all Toyota operations, the Georgetown plant adheres to the Toyota Production System, also known as “just-in-time” or “lean” manufacturing.
Over the years, Toyota had honed production at the Georgetown plant to a high level of efficiency. But there was still room for improvement when it came to the internal movement of parts. Workers delivering materials to different departments had to drive long distances, navigating congested areas to drop flow racks and palletloads of parts at work cells. Sudden stops, complicated workflow paths, and the occasional traffic jam or collision led to product damage and delayed deliveries.
A team assigned to study the problem determined that automating the transportation of parts to the 1 million-square-foot body-weld area—in essence, taking human drivers out of the equation—would eliminate most of the delay and damage problems.
Their conclusion may not be very surprising. What is surprising is the way Toyota accomplished that objective: Instead of purchasing new equipment, the factory chose to retrofit 22 of its Toyota 24-volt, AC-drive tow tractors with locally built automation kits that turned them into automatic guided vehicles.
To develop these “home-grown” AGVs, Toyota worked with two local business partners—AutoGuide, Utilizing the same off-the-shelf devices already in use for other types of AGVs at Toyota, AutoGuide outfitted the 10,000-pound-capacity tow tractors with obstacle and guidance sensors, radio-frequency modems, RFID tag readers, and a touchscreen programmable logic controller (PLC) interface, among other technologies.
To get where they’re going, the tow tractors follow over two miles of magnetic strip slotted into narrow troughs in the concrete floor. Their positions are tracked by RFID tags embedded in the floor.
Navigating the high-traffic body-weld department requires care and precision. To manage the movements of the automatic vehicles, The Toyota AGV implementation team worked with ICI to develop traffic-control technology that would be compatible with the guidance systems and control devices already in place for other types of AGVs. The resulting Automated Vehicle Intersection Navigational Utility (AVINU) is the link between the AGVs and everything else that’s automated.
The wireless system communicates with the different types of AGVs, reporting each one’s location, status, and performance data—information that can be viewed on any authorized computer in the facility.
According to Toyota, changing the way parts are delivered and reconfiguring the robotic welding cells has cut walking distances by 978 miles a year, saving five hours of walking time per shift—the equivalent of 317 work days annually. Furthermore, eliminating the storage pallets and flow racks opened up nearly 37 square feet of work space adjacent to each cell, freeing up space for other activities.
Because the AGVs travel the same paths at a consistent speed without so much as an inch of variation, they can safely navigate turns that would challenge human drivers—in some places, with less than six inches of clearance, according to Stafford. Congestion, collisions, sudden stops, and in-transit product damage have all been eliminated.
The labor savings have been equally impressive. The body-weld department has been able to reassign 42 people to other, more value-adding positions—including to the AGV implementation team—and nobody has been let go.
So far, the Toyota AutoGuide/AVINU project has saved Toyota more than $1 million annually, and ROI was achieved in just over one year. The payback has been substantial enough that the AGV implementation team will roll out the system elsewhere at Georgetown and will help to implement it at other Toyota auto plants.
The project foretells wider adoption of automation, not only in manufacturing but also in warehousing and distribution. In fact, AutoGuide attachments for Toyota pallet trucks and forklifts are already in the works.
One of those challenges will be to convince warehouse and DC operators that automatic vehicles are not as complicated and expensive to purchase, install, and operate as they might think. That may not prove particularly difficult, however: Meyer estimates that the cost of a new, mass-produced vehicle plus the AutoGuide automation kit would be approximately one-fourth that of a custom-built traditional AGV.
The economic downturn has forced companies to look for waste, cut costs, and introduce more process efficiencies while considering how to better prepare for rapid change. Automation can help in all of those areas, and lift truck manufacturers can play a leading role in bringing it to a wider audience.
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