Communications – electrical: acoustic wave systems and devices – Echo systems – Returned signal used for control
Patent
1998-10-01
2000-02-29
Lobo, Ian J.
Communications, electrical: acoustic wave systems and devices
Echo systems
Returned signal used for control
73636, 246167R, G01V 100, B61L 2928
Patent
active
060317906
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an information generating apparatus for transmitting and receiving elastic waves through a propagation medium and for generating information to be used for controlling/monitoring a system.
BACKGROUND ART
For example, a railroad crossing gate control operation performed in a current railway transportation system will be described hereinbelow.
When a train is detected by a train detection device that is provided at an approach detection point which is established at a predetermined place before a railroad crossing, a warning device starts sounding, and after a lapse of a predetermined time period since a sounding start point of time, a gate arm of a railroad crossing gate is caused to descend, as illustrated in FIG. 1. Thereafter, when it is detected that the train having entered the railroad crossing leaves there, the sounding operation of the warning device is stopped and moreover, the gate arm is caused to ascend.
Incidentally, a time period TX between a moment from when the gate arm starts descending until the train enters the railroad crossing, should be secured as, for example, a time period required for an automobile or the like left in the railroad crossing to get out there, and should be equal to or longer than a predetermined time period (of, for instance, 15 seconds). Additionally, the sounding operation of the warning device, which is performed to inform an automobile or the like traversing the railroad crossing of the fact that the train approaches the railroad crossing, should be commenced a predetermined time (T0 shown in this figure, which is, for example, 30 seconds) or more before a train enters the railroad crossing.
Hitherto, for the purpose of securing the aforementioned time periods TX and T0, the timing with which the sounding operation of the warning device is started (namely, the timing with which a crossing inhibition command is issued) is controlled on the assumption that, among trains passing through the railroad crossing, the fastest one passes therethrough.
However, there are various kinds of trains, which run through a same running section, from a high-speed express train to a low-speed freight train. Thus, if the sounding operation is started with the same timing by assuming that, among trains passing through a railroad crossing, the fastest one passes therethrough, in the case that a train of which speed is lower than that of the assumed train, passes through the railroad crossing, it takes time, which is longer than required, until the train reaches the railroad crossing after the sounding operation of the warning device is started, or after the gate arm descends. Consequently, the aforementioned time periods T0 and TX become extremely long, so that a time period, during which automobiles and passers-by are prohibited from traversing the railroad crossing, becomes longer than required.
To solve the aforesaid problems, there has been employed a railroad crossing gate control operation that is referred to as a constant time control operation of timing-controlling in such a manner that the lengths of the time periods T0 and TX are constant (see, for instance, Yoshimura and Yoshikosi, "Signal", Koyusha, 1958).
A method for performing a constant time control operation is a delayed control method by which kinds of trains such as an express, a local train and a freight train is detected and then, if a train is of the kind that runs at a low speed, the sounding operation of the warning device and the operation of the gate arm are delayed.
However, in the case of employing such a delayed control method, when a train which usually travels at a high speed, runs by reducing the travelling speed thereof owing to an occurrence of a trouble over train operations, a sounding time period, during which the warning device sounds, and a railroad crossing closing time period, during which the railroad crossing is closed by the crossing gate, become long, similarly as in the aforementioned case. Further, trains assigned to the kinds of low-spee
REFERENCES:
patent: 4578665 (1986-03-01), Yang
patent: 4932618 (1990-06-01), Davenport et al.
patent: 5627508 (1997-05-01), Cooper et al.
Futsuhara Koichi
Inose Katsuichi
Morisada Akira
Nozawa Hitoshi
Sakai Masayoshi
Lobo Ian J.
The Nippon Signal Co. Ltd.
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