Aging AGV (automatic guided vehicle) systems can be upgraded and made to deliver continued value to end users. A Procter & Gamble plant in Iowa City, Iowa, proves this point.

"In the early 1980s we initiated an aggressive, company-wide program to automate processing operations by employing automated guided vehicles and robotics to handle various simple and repetitive tasks," says Dale Hanson, a P&G engineer in the company's central engineering department in Cincinnati.

"By the early 1990s," Hanson continues, "most of the AGV systems were out of service because of difficulties in keeping them running." Only the dedication of a few technicians at the Iowa City site kept its AGV system going. But by the late 1990s even this system increasingly had more problems. Lack of spare parts made it more expensive to run, and eventually impossible to keep it in operation.

So P&G decided to retrofit the AGV system with user-friendly controls that have significantly reduced costs. The new controls also greatly improved the system's functionality.

The original AGVs, delivered to the plant in 1987, were determined to be beyond retrofit, economically. P&G purchased eight new AGVs from a manufacturer of the vehicles. These AGVs are designed to use the plant's existing guide path.

But the new AGVs also enable P&G to take advantage of advances in technology, such as the ability to travel off-wire, as Hanson points out. "As a result of this successful system modernization, we are again evaluating AGV systems for other facilities."

The AGV manufacturer's traffic control system runs on any PC under a Windows NT operating system. This software is tied into a PLC network and it allows control engineers to simply point and click for control commands.

"The main reason we wanted to keep our AGV system," says Rebecca Burton, AGV area leader at the plant, "is the travel distance between the packaging lines. The AGVs have a 2,000-ft guide path and it certainly makes sense for an unmanned vehicle to make that trip rather than tying up a forklift operator."

The Iowa City plant produces shampoo, conditioner, and mouthwash. "Our plant is kept very busy, operating 24 hours a day, seven days a week," says Burton. "We have a total of nine packaging lines and six supply conveyors. During the first shift everything is running at maximum capacity. During second and third shifts most lines are running, a few are shut down for scheduled maintenance checks and other performance functions."

The primary job of the AGVs, Burton continues, is to keep the packaging lines supplied with packaging materials. The AGVs are constantly moving, either delivering packaging materials, such as bottles and caps, to the line, or removing returns.

As part of the system's original design, there were areas along the guide path where a vehicle was forced to take long trips to make a U-turn. Conventional AGV systems solve this problem by cutting the floor and installing a new guide wire.

Today's AGVs, however, have the ability to travel off-wire, executing what is called a "programmed turn." The vehicle is able to travel a short distance off the guide wire and return to another path, using the vehicle's on-board programming and odometry for guidance. This feature has significantly increased the P&G system's overall efficiency.

AGV Products

704-845-1110

www.agvp.com