AGV Navigates By Laser

Saro, Sweden--Mounting a laser navigation system atop an automatic guided vehicle accomplishes three objectives when compared to wire-guided loop control: Increased flexibility in routing layout; lower installation costs; and improved performance.

Patented by NDC AB, the Lazerway(TM) concept for guiding automatic vehicles relies on a low-power IR scanner, retroreflective tape where angle of incidence equals angle of reflection, and a vehicle controller with a navigator card. System components work as follows:

The laser scanner generates a sweeping, invisible beam similar to those used for marine radar. Reflector tapes-fitted, for example, on the walls along the AGV's travel path-send the beam back to the scanner's photo detector. Connected by a serial link to the laser scanner and powered from the vehicle battery via a dc/dc converter, the navigator card calculates vehicle position based on the angles between reflectors and feedback from the steer/drive control. Bearing resolution is 0.045 degrees; positioning precision, plus or minus 2 mm.

Calculated position is then used to determine reference values for the vehicle's steering and driving motors, so that the AGV follows its prescribed route. The vehicle's controller executes actual movement and guidance control.

Because users generate transport routes on AutoCad, they can make traffic changes while the AGV continues to work. New drive routes are simply downloaded to the vehicle controller where they can be tested and, if necessary, further modified.

"Unlike wire-guided systems where new loops must be cut into the floor," says Company Chairman Anders Dahlgren. "Lazerway makes possible temporary adjustments to the flow of materials when installing new equipment." Dahlgren adds that, "it's never too late" to update conventional systems, as vehicles can be retrofitted to operate by laser as well as by inductive guidance systems.

Additional details, Europe...Contact NDC AB, Box 55, SE-430 40 Saro, Sweden, Tel: +46 31 93 60 20.

Additional details, U.S....Contact NDC Automation, Inc., 3101 Latrobe Dr., Charlotte, NC 28211-4849, (704) 362-1115.