Engineering News : Page 6 of 10

in 3-D space based on those specs. The rest of the machine is then built around Reggie.

Future plans for Hammer/Strength Inc. include the possibility of developing ergonomically-correct equipment for the office. Says Jones: "If we can think it, we can do it."


Denver airport finally in the bag

Denver, CO -Eighteen miles northeast of Denver and 30 feet underground lie 2 miles of train track upon which 30 million people a year will entrust their travels.

Or at least their luggage.

The track belongs to Denver International Airport's (DIA) fully-automated baggage handling system which, by an order of magnitude, is the largest in the world.

Developed by BAE Automated Systems (Dallas, TX), it consists of a fleet of 3,100 standard-size and 450 oversize destination-coded vehicles (DCV), or Telecars. DCVs roll the rails unpowered on sealed-bearing urethane wheels and resemble fiberglass updates of old-time mining cars. Regular DCVs handle bags up to 120 lbs, while the 6.5- x 4-ft oversized cars manage 350-lbs of skis, bikes or golf clubs.

Twenty-one hundred linear induction motors mounted beneath the track propel the cars at up to 1,750 fpm. Merges and loading operations occur at a more leisurely 600 to 700 fpm under the control of a friction drive and brake system. Concerned with aerodynamics and the possibility of blowing bags out of a car, engineers analyzed the DCVs in a wind tunnel.

Radio transponders attached to each car provide tracking data to a set of 55 networked computers running a custom Windows-based control program. The data is gathered by 400 radio-frequency identification (RFID) readers spaced at 150 to 200-ft intervals. Using inductive coupling, the readers interrogate the unpowered transponders allowing the system to guide full cars, manage empty cars, and identify problems with the cars or the track.

A bag's journey begins at check-in when agents attach a bar-coded destination tag. It then descends to a queue on a portion of the system's six miles of conveyors, passing one of 56 laser scanners on the way. The scanner reads the tag and triggers the computer to summon an empty DCV.

Like California commuters, bags ride one to a car. The system knows which DCV picked up which bag, and it uses RFID, not the bar-code tag, to steer bags to the proper gate. At the gate, the bag is either deposited in a holding area or passed to a conveyor and fed directly to the aircraft's cargo hold.

BAE has been blamed in part for a nearly two-year delay in the airport's completion (service began Feb. 28). The tardiness stems, BAE says, not from widely reported software glitches, gross "empty car" management problems, and fundamental design errors, but from the normal-yet unexpectedly lengthy-teething problems of a system 10 times larger than any ever built. "We simply underestimated the time needed to fine-tune a system of this size," says Gene Di Fonso, BAE's president. "It was like going from a DC-3 to a 747 without intermediate steps."

Problems that did challenge BAE engineers involved accurate speed control at merge points, motor overloads, temperature variations, and

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