JP3384362B2 - Vehicle axle number detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle number detecting device installed in a tollgate such as an expressway to detect the number of axles of a passing vehicle.

[0002]

2. Description of the Related Art For example, on toll roads such as highways, tolls vary depending on the number of axles of a vehicle, and a tollgate is equipped with an axle number detecting device for detecting the number of axles. Conventionally, a tread method has been the main method for detecting the axle. In this tread system, when a wheel passes over a contact-type sensor unit embedded in a road surface, the sensor unit is actuated by pedaling pressure, and the number of axles of a vehicle is detected from the number of times the sensor unit operates.

[0003]

By the way, according to the above-mentioned treading method, there is a problem that a lot of labor and cost are required for the work for embedding the contact type sensor portion on the road surface and the maintenance thereof. In order to solve this problem, a transmission type light beam blocking method (direct light receiving method) is known as a method using a non-contact type sensor. With this method,
The number of axles is detected from the number of times the light beam is blocked by the wheels.
However, according to this method, since it is necessary to adjust the position of the light beam to the position of the wheels, the optical transmitter and the optical receiver must be installed at a low position on the island of the tollgate, and special construction for the island is required. There is a problem that requires. In addition, this method has a problem in that other than wheels such as mudguards are erroneously detected as one axis.

There is also a laser pulse distance measuring method as another method, but since it is a method of receiving reflected light using an integrated sensor of transmission and reception, the sensor can be installed above. However, according to this method, since the transmitter and receiver of the laser pulse are located at the same position, there is a problem in that they are easily affected by weather, such as erroneous detection due to reflection from snow during snowfall, which reduces reliability. There is.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an axle detection device for a vehicle, which can be easily installed and can accurately detect the axle.

[0006]

In order to solve the above problems, the present invention has the following constitution. That is, the present invention relates to a vehicle that passes on a road surface (for example, a vehicle 13 described later).
Pulsed spot light (for example, a light-transmitting beam 8 to be described later) on the road surface so that a wheel of a component corresponding to
And a light projecting means (for example, a component corresponding to a light transmitting section 5 described later) for projecting light, and a light projecting means arranged to face the light projecting means. A light receiving unit (for example, a component corresponding to a light receiving unit 7 described later) that receives the spot light reflected on the road surface, and a pulse of the spot light received by the light receiving unit are counted,
Counting means for counting the number of axles of a vehicle passing on the road surface with a portion where pulses are continuously missing as one axis (for example, a component corresponding to a signal processing unit 11 described later)
And are provided.

According to this invention, the spot light projected from the light projecting means is reflected by the road surface and received by the light receiving means. Here, when a vehicle enters, the wheels of the vehicle block the spot light, and the pulse of the spot light received by the light receiving means is partially lost. The portion where this pulse is missing represents the wheel, that is, the axle, and the axle is detected from this missing portion.

[0008] Further, vehicle detection means for detecting the period from the vehicle head intrusion to the vehicle tail exit (for example, vehicle detection light emitting section 4, vehicle detection light receiving section 6 and signal processing section 11 which will be described later).
And the counting means is based on the number of pulses counted in a period detected by the vehicle detection means (for example, an element corresponding to an ON period of the output 14 described later). The number of axles may be counted.

Further, the pattern of the spot light projected on the road surface is a pattern which is vertically long in the direction orthogonal to the traveling direction of the vehicle (element corresponding to the pattern of the light transmitting beam 8 described later). Characterize. A reflection band (for example, an element corresponding to a reflection band 9 described later) that reflects the spot light may be provided on the road surface. Further, the light projecting means may be operated during the period detected by the vehicle detecting means.

The light projecting means and the light receiving means may be installed at the same elevation angle when viewed from the center of the road surface. As a result, the light receiving means receives the reflected light most efficiently (receives light).
it can. Further, even if the road surface becomes a mirror surface in the rain, it is possible for the receiving means to directly receive (receive) the reflected light.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an axle detection device for a vehicle according to an embodiment of the present invention. Figure 1
Shows a configuration of the axle detection device according to this embodiment as seen from the entry / exit direction of the vehicle 13. As shown in the figure, the light transmitting tower 2 and the light receiving tower 3 are provided on the island 1 on both sides of the road surface.
Are arranged respectively.

The light-transmitting tower 2 is provided with a vehicle-detecting light-emitting portion 4 and an axle-detecting light-transmitting portion 5 at the lowermost portion thereof. Spot-shaped pulsed light is provided by near-infrared LEDs (light-emitting diodes), respectively. Emits light. The vehicle detection light emitting unit 4 has a plurality of light emitter groups arranged in the vertical direction. Further, the light-transmitting beam 8 projected from the light-transmitting unit 5 has a vertically long (fan beam) light emission pattern and is irradiated onto the road surface 20. On the other hand, the light-receiving tower 3 is provided with a vehicle-detecting light-receiving unit 6 having a plurality of light-receiving units so as to face the vehicle-detecting light-emitting unit 4, and its lowermost portion faces the light-transmitting unit 5. A light receiving unit 7 for axle detection is installed in the vehicle. Vehicle light receiver 6
Receives the pulsed light (vehicle detection beam 12) from the vehicle detection light emitting unit 45, and the light reception unit 7 emits the pulsed light (light transmission beam 8 emitted from the light transmission unit 5 and reflected by the road surface 20. )
To receive.

FIG. 2 shows the configuration of the axle detecting device according to this embodiment as seen from above. As shown in the figure, on the road surface 20, there is provided a reflection band 9 (white band) for reflecting the light transmission beam 8 projected from the light transmission unit 5. The reflection band 9 may be omitted as long as the transmitted beam 8 has sufficient power. The axle-detecting light-receiving unit 7 has a light-receiving field of view 10 that matches the pattern of the light-sending beam 8 with which the road surface is irradiated.
It has an optical filter for removing unnecessary visible light on the front side, and uses a photodiode as a sensor. Further, a synchronization signal for timing adjustment is delivered from the light transmitting unit 5 to the light receiving unit 7. In the light receiving tower 3,
A signal processing unit 11 is provided for monitoring the output of the vehicle detection light receiving unit 6 and the output of the axle detection light receiving unit 7.

The operation of this embodiment will be described below with reference to FIG. A light emitting device (not shown) of the vehicle detecting light emitting portion 4 installed in the light transmitting tower 2 and the light transmitting portion 5 for detecting the axle.
Emits the vehicle detection beam 12 and the light transmission beam 8 at several hundreds to several kHz at different timings. The timing signal is delivered to the light receiving tower 3 as a synchronization signal,
The light receiving tower 3 receives the corresponding beams. When there is no vehicle, the vehicle detection beam 12 is always received, and at this time, the axle detection light transmission beam 8 may or may not be emitted.
The signal processing unit 11 counts the pulses of the output 14 of the vehicle detection light receiving unit 6 and the output 15 of the axle detection light receiving unit 7 and constantly monitors these.

Next, when the vehicle 13 enters, the vehicle detection beam 12 is first blocked by the vehicle head, and the output 14 of the vehicle detection light receiving unit 6 is turned on to prevent the vehicle 13 from entering the vehicle head. To be detected. When the vehicle 13 continues to enter, the transmitted beam 8 is blocked by the wheels (front wheels) of the vehicle 13, and the light receiving unit 7
The output 15 has a missing pulse. After that, a pulse is missing in the output 15 corresponding to each succeeding wheel.

Here, when the intrusion of the vehicle 13 into the vehicle is detected, the signal processing unit 11 detects a portion where the pulse of the output 15 of the light receiving unit 7 is continuously removed as one axis, and outputs the number of axles 1
Turn on 6. When the vehicle 13 exits and the exit of the vehicle tail is detected, the output 14 of the vehicle detection light receiving unit 6 is turned off, and the signal processing unit 11 stops the axle number output 16. Figure 3
In the example shown in (3), the axle number output 16 is turned on at three locations, and “3” is detected as the number of axles of the vehicle 13. As described above, the number of axles for each vehicle is accurately detected.

In this embodiment, the opposed transmitted light detection method is used for vehicle detection, but basically it can be used in combination with other vehicle detectors as long as there is no light interference. Further, in this embodiment, the near-infrared LE is used as the light beam for axle detection.
Although D is used, a semiconductor laser may be used instead of the LED.

Further, by controlling so that the light-transmitting beam 8 for axle detection is not emitted except when the vehicle is detected, the power consumption can be reduced and the life of the light emitting element can be extended. In addition, the light transmitter 5 and the light receiver 7
If the installation positions are set such that they have the same elevation angle when viewed from the center of the road surface, the light receiving section 7 can most efficiently receive the reflected light. Further, even if the road surface becomes a mirror surface in the rain, it is possible to directly receive the reflected light by the light receiving unit 7.

The effects of this embodiment will be summarized below. (1) Since the number of axles of a vehicle passing through a toll gate can be detected in a non-contact manner, it is not necessary to bury the work on a road surface like a tread method, and a low-cost device can be realized. (2) In terms of maintenance, it is possible to reduce costs by eliminating the need for tread replacement work. (3) No special processing work is required on the island. (4) The axle is detected only when the transmitted beam 8 is reliably blocked by a large object such as a wheel. Therefore, the mudguards other than the wheels will not be erroneously detected as one axis.

(5) The axle can be accurately detected without being affected by weather conditions such as snowfall. (6) The laser distance measuring method adopted in the conventional technique requires mechanical scanning such as a polygon mirror, but in the present embodiment, there is no mechanical moving part and the life of the device can be extended. (7) According to this embodiment, a situation may occur in which the axle cannot be accurately detected when the minimum ground clearance of the vehicle body is extremely low. However, since the vehicle that normally needs to detect the number of axles is a large vehicle, There is no practical problem. (8) If the light transmitting unit 5 and the light receiving unit 7 are installed at the same elevation angle when viewed from the center of the road surface, the reflected light on the road surface can be received most efficiently.

[0021]

As described above, according to the present invention, the light projecting means for projecting pulsed spot light onto the road surface so that the wheels of the vehicle passing on the road surface shield the light, and the light projecting means. Means for receiving the spot light projected from the light projecting means and reflected on the road surface, and the road surface based on the number of pulses of the spot light received by the light receiving means. Since the counting means for counting the number of axles of the vehicle passing above is provided, the device can be easily installed and the axles can be detected accurately.

Further, the vehicle further comprises vehicle detection means for detecting a period from the vehicle head intrusion to the vehicle tail exit, and the counting means is based on the number of pulses counted in the period detected by the vehicle detection means. Since the number of axles of the vehicle is counted, the number of axles of each vehicle can be detected. Further, since the pattern of the spot light projected on the road surface is a pattern that is vertically long in the direction orthogonal to the traveling direction of the vehicle, the light receiving means does not affect the state of the road surface. Light can be received and the number of axles can be detected stably.

Further, since the reflection band for reflecting the spot light is provided on the road surface, the light receiving means can receive the spot light even when the output of the spot light is small, and the light can be stably received. The number of axles can be detected. Further, since the light projecting means is operated during the period detected by the vehicle detecting means, the power consumption of the light projecting means can be reduced and the life of the light projecting means can be extended.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an axle detection device for a vehicle according to an embodiment of the present invention.

FIG. 2 is a diagram (top view) for explaining the configuration and the light emission pattern of the vehicle axle detection device according to the embodiment of the present invention.

FIG. 3 is a waveform diagram for explaining the operation of the vehicle axle detection device according to the embodiment of the present invention.

[Explanation of symbols]

1: Island 2: Light transmission tower 3: Light tower 4: Light emitting part for vehicle detection 5: Light transmitter 6: Light receiving part for vehicle detection 7: Light receiving part 8: Transmitted beam 9: Reflection band 10: Receiving field of view 11: Signal processing unit 12: Vehicle detection beam 13: Vehicle 20: Road surface

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-8-293090 (JP, A) JP-A-53-41251 (JP, A) JP-A-10-320687 (JP, A) JP-A-11- 120480 (JP, A) JP 8-273091 (JP, A) JP 4-257087 (JP, A) JP 57-189295 (JP, A) JP 10-105866 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G08G 1/015 G08G 1/04

Claims (5)

(57) [Claims] 1. A light projecting means for projecting pulsed spot light onto the road surface so that a vehicle wheel passing on the road surface blocks light, and the light projecting means is arranged so as to face the light projecting means. A light receiving means for receiving the spot light projected from the means and reflected on the road surface, and a pulse of the spot light received by the light receiving means.
And a counting means for counting the number of axles of the vehicle passing on the road surface with a portion where the pulse is continuously missing as one axis, and the number of axles of the vehicle. apparatus. 2. A vehicle detection means for detecting a period from a vehicle head intrusion to a vehicle tail exit is further provided, wherein the counting means is based on the number of pulses counted in the period detected by the vehicle detection means. The number of axles of the vehicle is counted.
The vehicle axle number detection device described in 1. 3. The number of axles of a vehicle according to claim 1, wherein the pattern of the spot light projected onto the road surface is a pattern which is vertically long in a direction orthogonal to the traveling direction of the vehicle. Detection device. 4. The vehicle axle number detecting device according to claim 1, wherein a reflection band for reflecting the spot light is provided on the road surface. 5. The vehicle axle number detecting device according to claim 1, wherein the light projecting means is operated during a period detected by the vehicle detecting means.