JPH039095Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a vehicle sensor that detects the presence or passage of a moving object such as a car.

[Conventional technology]

Conventionally, the right turn instruction from a traffic light adjusts the time allowed for a right turn according to the number of right-turning vehicles, and for this reason, it is necessary to detect the number of passing vehicles in the lane on the median strip side near the traffic light. In order to detect the number of passing vehicles, conventional methods have been to install an overfringe that covers the entire width of the road, install an ultrasonic vehicle detector on top of the overfredge, or bury a loop coil in the road surface. .

[Problem that the invention attempts to solve]

However, installing an overbridge requires high construction costs, making it uneconomical.
The method of burying the loop coil has the disadvantage that the coil cannot be easily maintained.

[Means for solving problems]

In order to solve these drawbacks, this idea
It is composed of a vehicle sensing section provided near the center of the road, and a light receiving section provided at the end of the road to receive the sensing results of the vehicle sensing section.

[Effect]

The sensing result of the vehicle sensing section is transmitted to the light receiving section.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of this invention. In the figure, 1 is a support provided at the end of the roadway, 2 is a receiving section, 3 is a solar cell, 4 is a transmitting section, and 5
is a vehicle sensing device, 6 is a battery, 7 is a median strip, 8
9 is a passing lane, 9 is a vehicle to be detected, and 10 is a support provided in the median strip 7. Receiver 2 is transmitter 4
It is located at a position where it can detect the carrier infrared rays emitted from the sensor. The vehicle sensing device 5 controls the transmitter 4 so as to transmit infrared rays intermittently at all times, but when it detects that the detected vehicle 9 is in the overtaking lane 8, it stops transmitting the infrared rays. It is designed to control the transmitter 4. When the receiving section 2 stops receiving infrared rays from the transmitting section 4,
It is designed to send out a vehicle detection signal.

FIG. 2 is a block diagram showing an example of the vehicle sensing device 5 and the transmitter 4 installed in the median strip. In the figure, the vehicle sensing device 5 includes a light emitting diode 5 ₁ that emits infrared rays, a light emitting circuit _{5 2 that} supplies current to the light emitting diode 5 1 , and gate circuits 5 ₃ and 5 .
_4. Reference oscillation circuit 5 that generates a rectangular wave of approximately 10KHz.
_5. Repetitive period oscillation circuit ₅₆ that generates a pulse waveform with a width of 1 millisecond approximately every 100 milliseconds, Light emitting diode ₅₇ , Amplification circuit ₅₈ , Comparison circuit ₅₉ , Reference voltage generation circuit ₅₁₀ , Synchronous detection circuit 5 ₁₁ , counting circuit 5 ₁₂ ,
It consists of 5 ₁₃ output circuits. The synchronous detection circuit ₅₁₁ is designed to generate a detection output when signals input to terminals a and b are synchronized. Furthermore, the gate circuit 5 ₃ , the reference oscillation circuit 5 ₅ , and the repetition period oscillation circuit 5 ₆ constitute a control signal generation circuit 5a. The amplifier circuit 5 ₈ , the comparison circuit 5 ₉ , the reference voltage generation circuit 5 ₁₀ , and the synchronous detection circuit 5 ₁₁ constitute a demodulation circuit 5b. Counting circuit 5 ₁₂ , output circuit 5
₁₃ constitutes a vehicle sensing signal generation circuit 5c.

The operation of the device configured in this way is as follows. The output signals of the reference oscillation circuit ₅₅ and the repetition period oscillation circuit ₅₆ are supplied to the gate circuit _{53, so the gate circuit 53 outputs} a 10KHz control signal for 1 millisecond every 100 milliseconds. be done. That is, the control signal generation circuit 5a generates a 10KHz signal (an intermittent signal that is intermittent multiple times) for 1 millisecond (first time), and generates the intermittent signal every 100 milliseconds (more than the first time). (long second time period) to generate a control signal. Since this signal is supplied to the light emitting circuit ₅₂ , a current synchronized with the control signal is supplied to the light emitting diode ₅₁ , and the light emitting diode ₅₁ intermittently repeats at 10KHz for 1 millisecond every 100 milliseconds. Infrared rays are emitted.

This infrared rays are sent toward the overtaking lane 8, and when a detected vehicle 9 is present there, it is reflected, received by the light emitting diode ₅₇ , amplified by the amplifier circuit ₅₈ , and supplied to the comparison circuit ₅₉ . When this signal is larger than the signal generated from the reference voltage generation circuit ₅₁₀ , the comparison circuit ₅₉ sends the signal supplied from the amplifier circuit ₅₈ to the synchronous detection circuit ₅₁₁ . Synchronous detection circuit 5 ₁₁
Since the control signal is supplied to terminal a, only those signals synchronized with the control signal among the signals supplied to terminal b are detected and output. Since the input signal is a rectangular wave having a repetition rate of 10 KHz for 1 millisecond, its period is 0.1 millisecond, and the output signal is sent out 10 times in 1 millisecond. No output signal is sent out for the next 100 milliseconds, and then again for the next 1 millisecond. That is, the demodulation circuit 5b demodulates the control signal from the reflection detected by the light receiving diode ₅₇ . Counting circuit 5 ₁₂ input pulse 8
When the vehicle is counted, a vehicle detection signal is output and the signal is held for about 110 milliseconds.
This signal is passed through the output circuit 5 ₁₃ to the gate circuit 5 ₄
is supplied to That is, the vehicle sensing signal generating circuit 5c sends a continuous vehicle sensing signal to the gate circuit ₅₄ while the control signal is being supplied.

The gate circuit ₅₄ is supplied with a control signal from the gate circuit ₅₃ , and outputs a control signal when the vehicle sensing signal is not supplied from the output circuit ₅₁₃ .
When a vehicle sensing signal is supplied, no control signal is output. Therefore, a control signal is normally supplied to the light emitting circuit 4 ₁ of the transmitter 4, and the infrared rays sent out from the light emitting diode 4 ₂ are output via the lens 4 ₃ . However, when a vehicle detection signal is generated, this infrared ray is no longer output. Note that the infrared rays that are output are controlled by a control signal, so the infrared rays emitted are 10K for 1 millisecond every 100 milliseconds.
It occurs with repetition of Hz.

Since the power supplied to the vehicle sensing device 5 and the transmitter 4 is provided by the power generated by the solar cell 3 and stored in the battery 6, there is no need to lay a power supply line to the median strip. . Note that the reason why the infrared rays are transmitted in a pulsed manner is to reduce power consumption and enable the use of a battery 6 with a small capacity.

FIG. 3 is a block diagram showing an example of the receiving section 2. Infrared rays are collected through a lens ₂₁ into a light receiving diode ₂₂ , where they are converted into electrical signals, and then
The signal is amplified by the amplifier circuit 2 ₃ and supplied to the comparison circuit 2 ₄ . When the level of the signal supplied from the amplifier circuit _2-3 is higher than the signal supplied from the reference voltage generation circuit _2-5 , the comparator circuit 2-4 inputs the signal supplied from the amplifier circuit _2-3 to the counting circuit _{2-6 .} supply That is, the signal detected by the light emitting diode 2 ₂ is demodulated by the demodulation circuit 2a.

The counting circuit ₂₆ is reset each time a signal is supplied from the reference oscillation circuit ₂₇ , and the generation frequency of the reference oscillation circuit ₂₇ is set to 1KHz, which is sufficiently lower than the repetition frequency of the received light pulses, 10KHz. There is. Therefore, for example, if an output is generated when eight received light pulses are counted, this signal will be reset after 1 millisecond, but will be generated again after 100 milliseconds. Then, by outputting the output signal of the counting circuit ₂₆ via the output circuit ₂₈ and holding it there for about 110 milliseconds, the output signal can always be obtained from the output circuit ₂₈ when there is a received light pulse.
However, when the light reception pulse stops, the receiver 2
After 110 milliseconds, it stops sending out the output signal and outputs information about the vehicle detected. That is, the holding circuit 2b
is adapted to generate a continuous output signal when an intermittent signal in the control signal is repeatedly supplied.

As shown in Fig. 1, if the mounting position of the light emitter 4 is set lower than the mounting position of the receiver 2 and its height is set to an appropriate value, infrared rays will be blocked even when a large vehicle passes. It is possible to detect that the vehicle is a large vehicle. Continuous vehicle sensing can also be determined as a fault. Further, the infrared rays may be ultrasonic waves.

[Effect of idea]

As explained above, this design uses a carrier to transmit the sensing output of the vehicle sensing unit located near the center of the road to the edge of the road, so it is more economical and easier to maintain than conventional systems. It has the effect of

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of this invention, Fig. 2 is a block diagram showing an example of a vehicle sensing section, and Fig. 3 is a block diagram showing an example of the vehicle sensing section.
The figure is a block diagram showing an example of a light receiver. 2... Receiving unit, 4... Transmitting unit, 5... Vehicle sensing device, 7... Median strip, 8... Overtaking lane, 9...
...Detected vehicle, 2a, 5b...Demodulation circuit, 2b...
...Holding circuit, 5a... Control signal generation circuit, 5c...
...Vehicle sensing signal generation circuit.

Claims (1)

[Claims for Utility Model Registration] A vehicle sensing system comprising a vehicle sensing device 5, a transmitter 4, and a receiver 2, wherein the vehicle sensing device 5 is installed in a median strip and generates a control signal. The circuit 5a generates an intermittent signal that is intermittent multiple times for a first time, and the intermittent signal is
A control signal is generated by repeating it every second time period that is sufficiently longer than the time period of , and while the control signal is being sent out, the light emitting circuit ₅₂ is driven, and the light emitting diode ₅₁ is directed toward the passing lane. When an infrared ray is transmitted and the infrared ray is reflected from a vehicle traveling in the overtaking lane, the reflected wave detected by the light emitting diode ₅₇ is demodulated into a control signal by the demodulation circuit 5b, and the output is sent to the vehicle detection signal generation circuit. 5c, the vehicle sensing signal generation circuit 5c sends out a continuous vehicle sensing signal to the gate circuit ₅₄ when the control signal is being supplied, and the gate circuit ₅₄ when the vehicle sensing signal is not being supplied. The control signal supplied from the control signal generation circuit 5a is output to the transmitter 4, and the transmitter 4 sends a carrier toward the receiver 2 only while the light emission signal is supplied from the gate circuit ₅₄ . The receiver 2 is installed on the side of the road, and the transmitter 4
The carrier sent from the photodetector diode 2 ₂
A vehicle sensing device is characterized in that the control signal is detected by a demodulation circuit 2a, the control signal is demodulated by a demodulation circuit 2a, and a continuous output signal is generated when an intermittent signal in the control signal is repeatedly supplied by a holding circuit 2b. system.