You check in your bag at an airport desk. A conveyor belt whisks it away and the next time you see it you are in another airport, possibly on the other side of the world. Behind the scenes, a supercomputer’s worth of processing power has been applied to route the bag through a veritable maze of sorting procedures to the correct destination.
A wonder of automation? Well, not quite. In spite of the gee-whiz technology in the rest of the handling system, the actual handling of the baggage is still done by hand. This ties up a lot of staff – staff that could be more usefully engaged – in an arduous, hazardous and repetitive task.
Help is now at hand. Last autumn, ABB Airport Technology, in close cooperation with ABB Corporate Research, installed a pilot automated baggage loading system in Zurich airport.
The robotised loader itself is only part of the system. Before the physical handling can take place, two other operations are necessary – bag analysis and loading sequence planning.
The baggage screening system is where the bag weight, size, destination, flight class and bounding box (a conceptual rectangle in which computers place onscreen objects) are determined. Based on the data obtained from the screening, the robot is able to establish stacking models for optimized load ratios, i.e. the best usage of space in a Unit loading device, or ULD.
The bags pass three major sensor units on their way through the analyzer: first, a barcode laser scanner reads the tags on the bags to identify and link them to the flight data in the airport departure control system. Then the bags are weighed, on the fly, by a dynamic weighing scale. The weighing can be performed on conveyor belts moving at speeds of up to 2 m/sec. After this, the bag geometry is scanned. All these sensor inputs are used to classify the bag in a scheme which facilitates fully automatic bag handling. The calculation is performed in real time as the bags pass through the analyser.
This intelligent software module, known as the Baggage Classification Manager (BCM), was specially developed by ABB for this product.
Once the various bag parameters have been established by the BCM, the Load Control Manager (LCM) decides the order in which the bags are to be loaded into the ULD. Not all the bags, however, are loaded in the order in which they arrive; standard bags are quickly and safely arranged in the ULDs, but those having an unusual shape or weight are temporarily stored in adjacent racks until there is a suitable space available.
The system does not work autonomously; besides using the data from the BCM, the LCM also receives information from the airport flight information system. This can reveal, for example, if the passenger has already checked in and if the bag is eligible to be loaded.
Furthermore, the Feedback Control Manager keeps track of the currently available space, and its shape, in the ULD and informs the LCM. The FCM uses laser scanning to verify the accuracy of the information – if the bags should shift unexpectedly, the data is passed to the LCM, which reacts immediately and re-adjusts the next load position, selects another bag or, in a critical situation, forces an operator action.
In addition, a ‘loading list’ is created which contains the accurate weight of each ULD and details of where each loaded bag can be found. This makes life easy should an item of baggage have to be off-loaded (a plane may not fly with baggage whose owner has not joined the flight). Many flight delays are due to handler crews hunting through aircraft baggage holds for a particular piece of luggage.
Two basic configurations are available for the robot: stationary and mobile. In the former, the robot remains in one position, surrounded by a number of ULDs, and is ‘fed’ bags by two conveyor belts.
In the mobile arrangement, the robot travels along a track which has a conveyor baggage feeder at each end . Bags are picked and placed in any one of a number of ULDs. The mobile configuration allows more ULDs to be serviced.
The intensity of operations and local topography will determine which configuration is selected for a particular location.
Different tools allow the robot to scoop the bags from the conveyor and transfer them to a shelf of an ULD. The tools can be changed on the fly; there is a tool-change station within the cell. Tool selection is determined by the LCM, bearing in mind the bag classification and calculated bag position. In this sense, the robot is ‘dumb’, receiving, as it does, its instructions from the LCM, ie it is not equipped with intelligent vision systems.
On average, a human worker handles 20-30 bags per hour. Depending on the robot cell design, the capacity of the automated baggage loading system can be from 120 to 300 bags per hour. And whereas manual loading is done in three shifts, the robot hardly ever has to stop (availability is projected to be 95%).
But the human element is not completely absent: An operator, who may oversee up to 4 stations, must be available at all times. Should he need to, the operator can force the robot to go to the ‘Home’ position and re-initialize the set-up.
ABB representatives say that the technology used for bag loading can be easily adapted to a wider range of applications, e.g., distribution of goods and commissioning.
Source: ABB review