NL9001964A - IDENTIFICATION SYSTEM FOR VEHICLES USING RAILS. - Google Patents

Description

Nedap N.V./ I 31

Identification system for rail-moving vehicles

Hr. J. Saeys

Hr. W. Venema

The invention relates to an extension of the recognition system, the coded label of which is described in the Dutch patent applications 7711891 and 8501581 of the applicant. In this recognition system, an electronic reading unit, also technically referred to as an interrogator, an electronic label, also referred to as a responder, can read a code stored in the label and thereby recognize the label. In principle, such a responder contains a coil, a capacitor and a coding circuit. If the responder is brought into an electromagnetic interrogation field, generated by a transmitter / receiver, the coding circuit can be fed via the LG circuit and the generated code can also be transferred again via the same LC circuit. The coupling between the reader and the label takes place by means of magnetic induction. That is, both the electronic reading unit and the label contain a coil with an extended external magnetic field, so that a magnetic coupling occurs between the two coils, while the coils are spaced well apart, typically about 1 meter. The time typically required to accomplish this recognition is approximately 250ms.

The drawback of this technique is that it does not offer the possibility of recognizing labels at a great distance or at great speed, because they are either too far away from the interrogation field or are not in the interrogation field long enough. These drawbacks may arise when identifying, for example, rail moving vehicles. The present invention overcomes these drawbacks by ensuring that the aforementioned label is in the interrogation field longer than usual by using a so-called induction loop. In the case of vehicles traveling on rails, this loop can be formed by a system of rails, an axle of the aforementioned vehicle and a connection between the rails. If a transceiver located in the vehicle induces a current in this induction loop through the axis of said vehicle, this loop can function as an antenna for said transceiver. A label located in this induction loop is coupled in this way with the transceiver located in the vehicle. To optimize this coupling, the connection between the rails can be designed as a winding in which the label to be interrogated is applied. In this way, the field generated as a result of the current flowing in the induction loop is optimally coupled to the label. The construction created in this way offers the advantage that the label can already be detected at a distance of approximately 100 meters. Assuming a typical recognition time of 250ms, this means that, theoretically, the vehicle can recognize the label at a maximum speed of 400m / s. It should be noted that if the above arrangement is reversed, wherein the transceiver is replaced by a responder and the responder by a transceiver, it is possible to identify individual vehicles.

The invention will be further described below with reference to the figures.

Figure 1 shows an overview of the aforementioned detection loop;

Figure 2 shows the detection label present in the winding connection between the rails;

Figure 3 illustrates the current in the axle of the vehicle induced by the transceiver.

Figure 1 shows a detection loop consisting of rails (1), an axis (5) and a winding connection (3) between the rails.

A current in axis (5) is induced by transmitter / receiver (7) via induction loop (6). This causes current to flow in the aforementioned detection loop. Current also flows through the winding connection (3), which is galvanically attached to rails (3) by means of the points (2). The aforementioned current I ^ generates an electromagnetic field in circuit (3), which is induced in responder (4). In this way, the interrogation signal from the electronic reading unit (7) reaches the label (4) and the information signal is reversed from the label (4) to the reading unit (7).

In this way, a detection distance of about 100m can be achieved. If several responders are on the route, at such a distance from each other that it is larger than the above 100m, multiple responders can be used in the same route, so that, for example, the place where the vehicle is located can be determined if the label available information makes this possible.

Figure 2 shows the aforementioned detection label (4), consisting of coil (8) and electronic coding circuit (9). This coding circuit (9) is supplied with energy via the LC circuit formed, of which coil (8) forms a part.

Figure 3 shows a detail of Figure 1 where current 1 ^ generated by transmitter / receiver (7) induces a current I in axis (5) by means of the electromagnetic field (10). This method has made the use of, for example, sliding contacts superfluous, whereby the service life of such a system is considerably improved, and the signal path is considerably less disturbed by disturbances between moving metal parts occurring in practice.

Claims (3)

An electromagnetic detection system for the purpose of identification of vehicles moving on rails or determination of the position of these vehicles, or the routes on which they are located, characterized in that the recognition of an induction-acting label at a distance of up to approx. 100 may take place, using the rails already present and a vehicle axle, which together with an arranged connection between said rails form an induction loop, whereby this system can be applied at the speeds of the vehicles mentioned in practice. An electromagnetically operating detection system according to claim 1, characterized in that the coupling between the electronic reading unit or the electronic label is effected by the induction loop mentioned in claim 1, wherein the said reading unit is inductively coupled to the axis of the vehicle, so that the use of, for example, towing contacts is unnecessary. An electromagnetically operating detection system according to claims 1 or 2, characterized in that a transmitter / receiver is fitted at the location of the responder and a responder at the location of the transmitter / receiver, in order to be able to identify vehicles individually.