JPH0241756Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a vehicle information transmission system that detects information regarding passing vehicles, such as cargo information, vehicle affiliation, etc., without contact.

[Prior Art] Generally, when a relatively large-scale civil engineering project is carried out, it becomes necessary to dispose of a large amount of leftover soil, and for this reason, it is necessary to transport the leftover soil to a dumping site using a large number of dump trucks. In this case, the civil engineering business owner requests a contractor who owns dump trucks to transport the remaining soil, but if a large number of dump trucks are required, the number of dump trucks owned by one contractor is insufficient, so multiple contractors are hired. We have secured the required number of dump trucks through a contract. Each contractor is then compensated on a piece-rate basis based on the amount of surplus soil transported.

Conventionally, a system shown in FIG. 3 has been used to measure the amount of production. In the figure,
A vehicle 1 such as a dump truck that travels on a predetermined road is equipped with a transmitter 1a that converts vehicle information such as the weight, type, and vehicle number of the loaded object into infrared pulses and sends them out. It runs while sending out infrared pulses modulated by
Then, when the vehicle 1 reaches the vicinity of a terminal device provided on the side of the road indicated by a dotted chain line, the infrared rays being sent out from the transmitter 1a are detected by the light receiver 2 in the terminal device. The vehicle information content of the signal detected by the light receiver 2 is identified by the light-receiving signal discriminator 3, where it is temporarily stored and sent to the track 5 via the information transmitter/receiver 4. The signal sent to the line 5 is demodulated by the information transmitter/receiver 6 of the central device shown by the two-dot chain line, and the processed output is sent to the central processor 7.
The processing results are recorded on a floppy disk within the central processing unit 7. Then, a reception completion signal is sent to the terminal device via the information transmitter/receiver 6 to notify that the information content has been stored, and then the vehicle information and the time of arrival are output to the printer 8.

The reception completion signal transmitted via the line 5 is received by the information transmitter/receiver 4 of the terminal device, and is supplied to the indicator lamp drive circuit 9, so that the indicator lamp 10 lights up.
As a result, the driver of the vehicle 1 can know that the vehicle information has been recognized and recorded by the central device.

[Problems that the invention attempts to solve]

However, since the light receiving detection angle range of the light receiver 2 cannot be very wide, the vehicle 1 is traveling at a speed of 60 km/h.
In order to completely identify vehicle information while driving, the pulse interval of infrared pulses is approximately 100 μs.
The emission pulse width is required to be approximately 3 μs. When this signal is received by the light receiver 2, a signal having a pulse width of about 2 to 6 μs is obtained.In order to accurately identify vehicle information from this signal, the light receiver 2 and the received light signal discriminator are required. 3 is allowed, and if the distance is longer than this, the waveform will be distorted and erroneous identification will occur. For this reason, the received light signal discriminator must be placed inside the terminal device, which not only deteriorates maintainability and reliability but also increases power consumption, making it impossible to supply power from the central device and using commercial power. It was necessary to withdraw the power, making it uneconomical.

[Means for solving problems]

In order to solve these drawbacks, this idea
By widening the pulse width of the signal obtained from the optical receiver and sending it to the line at a constant current, waveform distortion is less likely to occur even if the line becomes long, and the central device can reliably transmit vehicle information. This allows for identification.

[Effect]

Vehicle information can be identified using the central device.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of this invention, and the same parts as in FIG. 3 are designated by the same symbols. In the figure, an infrared pulse sent out from a transmitter 1a is detected by a receiver 2 of a terminal device 30, and is supplied to a monomultiviprator (hereinafter referred to as MM) 11, which is supplied with a pulse signal. When the pulse width is about 30 μs, the signal output from M.M11 is designed to output a signal with a pulse width of about 30 μs. The signal is output as a signal having a sufficiently longer time than this.
This signal is sent to the line ₅₁ via the current output circuit 12, detected by the signal converter 13 of the central device 31 (this signal converter 13 is realized by a photo coupler), and is detected by the received light signal discriminator 3. The vehicle information is detected there.

The current output circuit 12 and the signal converter 13 are
As shown in the figure, the current output circuit 12 is composed of constant current diodes 12a, 12b, a transistor 12c, and a resistor 12e, and a signal converter 1
3 is composed of a signal converter element 13a and a resistor 13b. Then, the output signal generated from M.M11 is passed through a resistor 12e to a transistor 12c.
At this point, the transistor 12c is turned on, and the constant current diode 12
A current whose value is determined by a, 12b is sent to the line ₅₁ . When this current is supplied to the signal converter element 13a, the transistor in the signal converter element 13a turns on and a voltage drop occurs across the resistor 13b.
is supplied to

The signal converter element 13a is an element that sensitively detects the presence or absence of current supplied thereto, and is not very sensitive to changes in the current value. Further, since constant current diodes 12a and 12b are used in the current output circuit 12, the current supplied to the signal converter element 13a hardly changes even if the length of the line changes.
Therefore, if the pulse width of the transmitted signal is set to 30 μs and the distance between the terminal device and the central device is approximately 2 km, the signal detected by the receiver 2 can be reliably transmitted to the central device. can be identified.

The signal identified by the received light signal identifier 3 is supplied to the central processing unit 7 as shown in FIG. 1, so vehicle information is recorded and printed, and the current output circuit 1
A reception completion signal is sent to line ₅₂ via line 52.
The reception completion signal is then supplied to the M.M. 17 via the signal converter 15 and the waveform shaping circuit 16.
If the operating time of the M.M 17 is about 5 seconds, the indicator light 10 will be lit only during this time.

The device of this invention can accommodate the received light signal discriminator 3, which was conventionally required on the terminal device side, in the central device, and the current consumption of the terminal device is eliminated because the information transceivers 4 and 6 are no longer necessary. As a result, it became possible to operate the device using DC power supplied from the central device. However, since the indicator light 10 requires about 50 watts of power to make the driver aware of its lighting status even during the day, the battery 18 is charged with a weak current using the power supplied from the central device, and the display is powered on. light 1
Electric power for lighting 0 is supplied from a battery 18. Note that commercial power is supplied only to the power supply 19 of the central unit, so if countermeasures against a power outage are required, countermeasures need only be applied to this section.

[Effect of idea]

As explained above, this invention lengthens the pulse width of the signal detected by the photoreceiver and makes it a constant current, which makes it difficult for waveform distortion to occur even if the line becomes long, resulting in erroneous identification. Therefore, the received signal discriminator can be housed in the central device, and the power consumption of the terminal device is reduced. Therefore, power to the terminal device can be supplied from the central device via the line. Since there is no need to connect commercial power to the terminal equipment, equipment costs and construction costs can be reduced, and since the main parts are housed in the central equipment, maintenance is easier and reliability is improved. It has many effects such as

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of this invention, FIG. 2 is a circuit diagram showing the current output circuit and photo coupler portions in FIG. 1, and FIG. 3 is a circuit diagram of a conventional device. _DESCRIPTION OF SYMBOLS 1...Vehicle, 2...Photoreceiver, 3...Received light signal identifier, _51-53 ...Railway, 7...Central processing unit,
8... Printer, 10... Indicator light, 11... Mono multivibrator (MM), 12, 14... Current output circuit, 13, 15... Signal converter, 18...
...Battery, 30...Terminal device, 31...Central device.

Claims (1)

[Claims for Utility Model Registration] A vehicle information transmission system comprising an on-vehicle transmitter 1a, a terminal device 30, and a central device 31', wherein the on-vehicle transmitter 1a is mounted on a vehicle and modulated with vehicle information. The terminal device 30 is installed at a predetermined roadside, and the light receiver 2 receives the light signal from the on-vehicle transmitter 1a, and inputs the light reception output. The mono-multivibrator 11 converts it into a pulse signal with a pulse width sufficiently longer than the pulse width of the optical signal, inputs the conversion output, and converts it into a constant current photocurrent signal into the current output circuit 12, and the line 5-1 Central device 3 via
The central device 31 transmits signals to the terminal device 3, and the signal converter 13
The vehicle information transmission system is characterized in that the photocurrent signal transmitted from 0 is detected, the detection output is input, and the received light signal discriminator 3 identifies the signal content and demodulates the vehicle information. .