Handling of Buffered Beamcars

As scarce as truth may be, the supply is still always greater than the demand (Winston Churchill, British prime minister during World War II)

uffered beam vehicles would be no problem to handle if every car was like any other car. But that is not the case in the FlyWay® system. Cars often have to be treated as individuals, mainly because: They are of different designs, for different purposes. Some individual cars might be booked for the entire evening. It should be possible for customers to leave their belongings in their cars while being away. An individual car might report problems, and has to be extracted from the buffer and directed to a maintenance workshop. Some beamcars might be privately owned, or belonging to companies, car pools or other parties, and not the property of the network operator.		This is a technical page, where we will examine beamcar addressing issues, how to localize parked cars, how to determine which cars are in the way, and (of course) how to move those cars out of the way. Contents of this page: General Using the addressing system Localizing a particular vehicle

1. General

n easy way of buffering beamcars would resemble the layout in figure 1:1. Here, every vehicle which is parked at the yellow berths is easily accessible, and can come out when called, without bothering other cars (provided, of course, that the access beams are not clogged). Such arrangements are expensive to build, however, because of the many shunts. A arrangement that would be cheaper to build, and which also could cram the vehicles into a smaller space, would resemble figure 2:2. In this example, we imagine the cars being buffered on the circular beams surrounding a sports arena. The arrangement would work after the same principles as the rotating clothesrack that can be found at drycleaners.

Figure 1:1.

2. Using the Addressing System

e will use the FlyWay® addressing system to localize any car we want. A closer peek at the circular buffering beams will reveal how it works. A system of 3 circular buffering beams within one another is shown in figure 2:3. In FlyWay®, all destinations, whether station berths, cargo loading berths, maintenance parking slots or buffering slots, have an hierarchical address, which follows a system which is explained on the page "The FlyWay Addressing System". This addressing system is hierarchical, and this makes it very flexible. In figure 2:3, the upper berths (on beam "2") are addressed from 2:1 to 2:10, the lower berths (on beam "3") are addressed 3:1 to 3:10, and so on. The 3 buffering beams are likewise logically numbered: A is beam 4, B is beam 5 and C is beam 6. As examples, we show the addresses of some parking slots on beam 6 (the innermost beam). Assuming a sudden influx of beamcars, because of a sporting event. Many cars will just leave their passengers and be on their way again. But the system will likely conclude that a lot of cars are not needed anywhere else, and should stay parked in the area until people leave for home again. As these cars leave their passengers at the berths and sign off from duty, the regional computer will direct the cars, first to the inner ring (C), by way of beams 1, 2 and 3, in that order. When the inner ring is filled (with a car in each addressable slot), the B-ring will be filled, using beams 1 and 2. When B is full, the outer ring will be filled, if needed. It will be noted that cars will not be permitted to block the "free zones" where the shunting beams join the buffer beams. When people leave the arena for home, the rings will be emptied in reverse order. First, cars on beam A will travel to the berths along shunting beam 6, to pick up passengers. When A is empty, cars on beam B will travel along beams 5 and 6 to pick up travellers. Beam C will be the last to empty. This arrangement can of course be expanded vertically a few tiers up, if needed. This would increase flexibility; beamcars would have more travel options when beams are allowed to cross at different levels. The parking procedure would be quite straightforward. The system knows at every moment which slots are occupied. Say, for instance, that slot 6:22 is already occupied. Then, the next car would be directed along beams 1, 2 and 3 to slot 6:21. The car after that would get slot 6:20, and so on. When slot 6:1 is filled, the next car would (of course) be directed to slot 5:32, which is the highest on beam B. The "free zones" have to be kept free of parked cars, so that access beams to and from the parking area are kept available. In the example, the free zone on beam B is quite large. A better beam architecture would probably be motivated.

Figure 2:2. Figure 2:3

he most common type of buffers are the straight beams, that are (usually) constructed as sidings along the thru-traffic beams. An example, outside a railway station, is shown in figure 2:4. The cars are more blocked here; they cannot circulate in order to free a car parked somewhere in the middle. The general solution for this is of course to not park vehicles that might need to be extracted on beams like this. These beams ought to be reserved for vehicles which are all the same as regards function. One way to ease the problem would be, however, to allow the buffered cars to move both ways, as shown in figure 2:5. They would not then be allowed to back out on a guideway with traffic; there has to be a guideway in-between these two, for manoeuvring purposes. Figure 2:5

Figure 2:4

3. Localizing a Particular Vehicle

e will also need to answer the question "How does the system know which vehicle is parked on a particular address"? and "Where can a particular vehicle be found?" In tthe FlyWay®system, all beamcars have individual identity-numbers, otherwise the tracking of cars would not function properly. Whenever a beamcar communicate with the system, this identity-number always accompany every information transmission from the car. Thus, in the foregoing example, the system knows not only which slots are filled, but also the identity of every car in every slot. So, the vehicle is easily localized. But how to extract it? Assuming that a traveller/customer wants a particular vehicle at a particular time, when the other vehicles are still there, in their slots, blocking the way. In such a case, the system quickly figures out: which vehicles are in the way how many slots each of them has to move forward to clear the way. Then, the system sends an order to each of the affected cars to move to their new parking slots. The requested car gets an order to move out of the buffer are, and to the assigned berth, where the customer might be waiting. As an example, say that the requested vehicle is in slot 6:6. Slots 6:12, 6:14, 6:20 and 6:23 through 6:28 are empty. We will give the vehicles arbitrary id-numbers, and call the requested vehicle "32". Then, the system would generate the table at right. This would seem to create 2 problems. The first problem is that most vehicles are asked to move to slots that are already occupied. This does not worry the vehicles, however; they don´t know which addresses are free or occupied, unless told so by the system. And the system (hopefully) knows what it is doing. The second problem is that the vehicles are almost bumper-to-bumper and cannot move. But that is not quite true. Some slots are empty; the vehicles in the slots behind can thus move one step forward, and so can the vehicle behind, etc. And the vehicles at the "free zones" can always move. So, starting with the cars in slots 6:11, 6:13, 6:19 and 6:22, the chain of vehicles moves to its new position, and the requested vehicle (number "32") goes to the berth to pick up the traveller.

Required vehicle motion to release vehicle "32" Vehicle From slot To slot 32 6:6 out 33 6:7 6:1 34 6:8 6:2 35 6:9 6:3 36 6:10 6:4 37 6:11 6:5 38 6:13 6:6 39 6:15 6:7 40 6:16 6:8 41 6:17 6:9 42 6:18 6:10 43 6:19 6:11 44 6:21 6:12 45 6:22 6:13