Lasers Plot The Best Route For Shop's AGVs

Nov. 21, 2006
Mitsubishi Motors North America has used automated guided vehicles in its metal stamping area since the Normal, Ill., plant opened in 1988.

Laser-guided vehicles run nearly maintenance -free at Mitsubishi's stamping department.

Mitsubishi Motors North America has used automated guided vehicles in its metal stamping area since the Normal, Ill., plant opened in 1988. However, the original system, a wire-guided one built in Japan, had several problems.

A digital mainframe computer that was not flexible enough or user-friendly controlled the system, and getting technical support proved time consuming and difficult. In addition, vehicle batteries would go dead several times a shift, often requiring a charge at inconvenient times, and antenna adjustments posed maintenance issues.

"Everyday-operating conditions were not our only concerns. If any change to the vehicle path was needed, it was difficult to do. Eventually, routine maintenance issues and complications when changes were needed resulted in a direct loss of system efficiency," says Barry Hansis, a staff engineer for stamping at Mitsubishi Motors.

The solution to the stamping area's problems was a new laser-guided system from AGV Products Inc. ( Unlike the plant's previous system, the one from AGV Products includes Odyssey vehicles made exclusively for laser-guided systems and an iCon navigational software package. Customer support now is just a phone call away, and replacement parts typically arrive overnight.

Within the new system, a Windows-based host PC controls and routes the vehicles, runs associated production-line cranes, oversees inventory, and schedules and controls deliveries. According to Hansis, the host computer constantly searches for the most efficient way to route the automated vehicles, and connects with other computer systems throughout the plant.

"The vehicles use a laser-guided technology that works extremely well and does not require continual attention to keep it running. Also, vehicle path changes can be made in a matter of minutes, and a quad capability allows each vehicle to have four-directional travel," says Hansis.

Mitsubishi shop personnel change vehicle paths with a simple click-and-drag operation on a personal computer, while management staff handles permanent guide-path changes. Associates on the floor do special deliveries, inventory changes, error recovery and daily operations. "The system runs at the directions of employees. They simply tell the system where they want a stack of material to be moved, and the system decides when, how and routing," explains Hansis.

Odyssey vehicles sport laser units mounted on masts and move freely, calculating their coordinates from reflectors that are permanently mounted in the stamping shop. On-board laser-guidance systems send out a light beam that is reflected back by one of the reflectors to provide reference points for the vehicles.

Instead of lead-acid batteries, the system's vehicles run on gel-filled batteries supplied by Waddell Battery Inc. of Peoria, Ill. These batteries can be charged each time a vehicle returns to its home position, eliminating the need to change batteries and reducing downtime.

Mitsubishi has the option to set up its vehicles as fork, unit load or tow-style. AGV Products also customizes vehicles for customers requiring conveyor decks, side-loading capabilities, special forks and other load-specific features. All Odyssey vehicles include an advanced safety system that has front, side and rear sensors, as well as bumper-detection systems.