JP2000339586A - Axle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of axle detection by constituting the axle detector so that the moving distance (the interval of a reflecting position) of an irradiation point in each pulse period of pulse light is sufficiently smaller than the cross-sectional height of a tire. SOLUTION: The width of a road is set up as L and it is supposed that a vehicle 24 of body width W passes a position most separated from an axle detector 21 arranged on the roadside 23 of the road at a vehicle speed V[m/sec]. When it is defined that a distance from the light projection part of the axle detector 21 up to a tire 48 is D[m] (D>-w) and the light emitting interval angle of pulse light projected from the detector 21 is Δθ [rad], the interval Δh[m] of the reflecting position of pulse light projected from the detector 21 on the tire 48 can be approximately expressed by Δh=D.Δθ. Thereby the interval Δh of the reflecting position of the pulse light is made sufficiently smaller than the cross-sectional height (a value obtained by subtracting the radius of an inner periphery from the radius of an outer periphery) of the tire 48 in order to improve the detection accuracy of the tire 48.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle detecting device for a passing vehicle in a toll collection device such as a toll road or a toll parking lot.

[0002]

2. Description of the Related Art In a toll road or a toll parking lot, it is necessary to count the number of axles (or the number of tires) of a passing vehicle in order to determine the type of the passing vehicle. Axle detection devices that detect the axle of a vehicle and count the number of axles include, for example, those using a tread plate system and those using an optical scanning system.

[0003] In the axle detecting device of the tread plate type, as shown in FIG. 1, a tread plate 2 is embedded in a road surface 1 so that when the vehicle 3 passes over the tread plate 2, the tire 4 presses the tread plate 2. By mechanically detecting, the number of axles of the vehicle 3 is detected.

However, in such an axle detecting device of the step plate type, the pressing force when the vehicle 3 gets over the step plate 2 is detected by the mechanical contact. Maintenance and inspection of the axle detector and parts replacement are often required. In this case, in the tread plate method, the axle detection device must be buried in the road again after the road surface 1 is dug up to take out the axle detection device from the road, and after the maintenance and inspection work is completed. The inspection required paving work on the road, and it was necessary to close the lanes on the toll road until the concrete on the road surface was solidified. On an elevated road such as an expressway in a city, the thickness of the road cannot be ensured, so that an axle detecting device of a tread plate type cannot be installed.

On the other hand, an optical scanning type axle detecting device 5
Is installed on the roadside 6 as shown in FIG. 2, so that the traffic of the vehicle 3 is not obstructed during the installation work. In the optical scanning type axle detecting device 5, a laser diode (L
D) After collimating the laser light pulse-emitted in 7 by the collimating lens 9, the laser light is scanned by the polygon mirror 10 along the road crossing direction, and the road surface 1 and the passing vehicle 3 are irradiated with the laser light. Light reflected from the road surface 1 or the vehicle 3 passes through a light receiving lens 11 to a light receiving element 12 such as a one-dimensional position detecting element (one-dimensional PSD).
Axle detection device 5 based on the principle of triangulation.
The distance from the object to the object is measured, and it is determined from the distance information in each scanning direction whether the object is the road surface 1, the vehicle body 8, or the tire 4.

[0006]

In the axle detecting device 5 of the above-described optical scanning system, as shown in FIG. 3, laser light (pulse light) is scanned on the tire 4 of the passing vehicle 3 by scanning. The tire 4 is detected. Therefore, in order to increase the detection accuracy of the tire 4, it is desirable that the number of irradiations (irradiation points) of the laser beam on the tire 4 of the passing vehicle 3 be large.

However, when the traveling speed of the vehicle 3 increases,
Since the scanning line density of the laser beam scanned on the passing vehicle 3 is reduced, the number of scanning lines scanned on the tire 4 is also reduced, and it becomes difficult to detect the tire 4.

Therefore, the tire 4 of the vehicle 3 running at high speed
It is necessary to increase the number of scans per unit time by, for example, increasing the number of rotations of the polygon mirror 10 in order to detect. However, since the laser light is emitted in pulses and is scattered as shown in FIG. 4, if the rotation of the polygon mirror 10 is increased to increase the number of scans per unit time, the scanning speed of the laser light increases. Become 1
The number of laser light emission in the scanning is reduced, and the interval Δh between the irradiation points of the laser light shown in FIG. 4 is increased. Conversely, 1
To narrow the interval Δh between the irradiation points of the laser beam in the scanning, the number of scans per unit time must be reduced. Therefore, in any case, it is difficult to increase the detection accuracy of the tire 4, and it is particularly difficult to correspond to the vehicle 3 passing at high speed.

In order to increase the number of scans per unit time and not to decrease the number of laser light emission in one scan, it is necessary to shorten the pulse emission cycle of the laser diode. If the period is shortened, the life of the laser diode is shortened, and there is a limitation in shortening the light emitting period of the laser diode from the viewpoint of ensuring safety.

Further, in the optical scanning type axle detecting device, since the laser light is reflected by the exhaust gas, when the laser light reflected by the exhaust gas is received by the light receiving element, the exhaust gas is erroneously detected as the tire of the vehicle. As a result, there was a problem that the number of axles of the vehicle was misread.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to improve axle detection accuracy in an optical scanning type axle detection device. In particular, it is an object of the present invention to improve the axle detection accuracy of a vehicle passing at a high speed or to improve the axle detection accuracy of a vehicle by preventing erroneous detection due to exhaust gas.

[0012]

The axle detecting device according to the present invention comprises a light scanning means for scanning a pulse light toward a detection area, and a scanning direction detecting means for detecting a scanning direction of the pulse light. Means, light receiving means for receiving light scanned by the light scanning means and reflected at the irradiation point, and distance calculating means for calculating the distance to the irradiation point of each pulse light based on a light receiving signal from the light receiving means And information on the scanning direction obtained by the scanning direction detection means,
In the axle detection device including a tire detection unit that detects the presence or absence of a tire based on the distance information to the irradiation point obtained by the distance calculation unit, it is assumed that the vehicle travels in a region farthest from the optical scanning unit in the detection region. The distance traveled by the irradiation point for each pulse cycle of the pulsed light is set to be sufficiently smaller than the height of the cross section of the tire on the tire of the vehicle.

In this axle detection device, the number of times of pulse light applied to the tire farthest from the device and in a condition where the tire detection condition is poor is sufficient for tire detection, so that the entire detection region is detected. Tires can be detected, and the detection accuracy of tires or axles can be improved.

According to a second aspect of the present invention, there is provided an axle detecting apparatus according to the first aspect, wherein a distance to a tire of a vehicle which is assumed to travel in a region farthest from the optical scanning means in a detection region is determined. D, A is the minimum length of a tire portion that can be identified as a tire by optical scanning, A is the moving distance of the irradiation point for each pulse cycle of the pulse light on the tire of the vehicle, and ΔH is the pulse light by the optical scanning means. When the scanning angle is θt, the assumed maximum speed of the vehicle passing through the detection area is V, and one pulse cycle time of the pulse light is Δt, the distance D is D <(A × △ h) / (V × θt × Δt).

Under the conditions satisfying the above equation, at least one of the tires of a vehicle passing at a speed V on the side far from the apparatus is also provided.
Since the scanning lines can be run, the tire or the axle can be reliably detected, and the axle detection accuracy can be improved.

According to a third aspect of the present invention, the axle detecting apparatus scans the pulse light toward the detection area, calculates the distance to each irradiation point based on the reflected light, and obtains the distance information to the irradiation point and each pulse. Tire detecting means for detecting the presence or absence of a tire in a detection area from the light scanning direction, and being installed on or near the same plane as the scanning surface of the pulsed light, and detecting the presence or absence of a vehicle in or near the detection area. Vehicle detection means.

In this axle detection device, the presence or absence of a vehicle can be detected by the vehicle detection means at the same detection position as that of the tire detection means, so that the exhaust gas and the tire can be distinguished. Erroneous detection is eliminated.

According to a fourth aspect of the present invention, there is provided the axle detecting device according to the third aspect, wherein the vehicle detecting means includes:
The light emitted toward the detection region is recursively reflected by the regression reflection plate, and the presence or absence of the vehicle is detected by receiving the reflected light. The present invention is characterized in that a retroreflective plate used in the sensor is used.

In this axle detection device, the cost can be reduced because the retroreflector of another sensor is used. Also, the installation space for the retroreflector can be reduced.

According to a fifth aspect of the present invention, there is provided an axle detecting apparatus according to the third aspect, wherein the tire detecting means has a function of detecting the presence or absence of an object having a height equal to or higher than a predetermined height on a road surface. An abnormality of the vehicle detection means is detected based on a detection result by the object presence / absence detection function of the means and a detection result of the vehicle detection means.

In this axle detection device, since the abnormality of the vehicle detection device can be detected by the tire detection device, the reliability of the axle detection device can be improved at low cost.

According to a sixth aspect of the present invention, there is provided an axle detecting device according to the third aspect of the present invention, wherein a retroreflective plate or a light receiver is provided so as to face the tire detecting means. It is characterized in that the presence or absence of the vehicle in the detection area can be detected by the pulsed light that is emitted toward and scanned toward the retroreflective plate or the light receiver.

In this axle detection device, the presence or absence of the vehicle can be detected by using the pulse light of the tire detection means, so that the configuration can be simplified and the cost can be reduced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 5 shows an axle detecting device 21 according to an embodiment of the present invention.
It is a schematic perspective view which shows the state installed in No.3. FIG. 6 is a block diagram showing the configuration of the axle detection device 21. FIG. 7 is a schematic diagram showing how the axle of the passing vehicle 24 is detected. First, the overall configuration of the axle detection device 21 will be described mainly with reference to FIG.

The light projecting section of the axle detecting device 21 includes a light emitting element 25 such as a laser diode (LD), a light projecting lens 26 for collimation, and a light emitting element driving circuit (LD driver) 27. The optical scanning unit includes a polygon mirror 28 and a polygon mirror driving circuit 29 (a motor driver for controlling a motor of the polygon mirror 28). Light emitting element drive circuit 2 from controller 30
When the drive command is output to 7, the light emitting element drive circuit 27 causes the light emitting element 25 to emit a pulse light at a predetermined light emitting cycle,
The pulsed light emitted by the light emitting element 25 is collimated by the light projecting lens 26 and then the small hole 3
2 and enters the reflecting mirror surface of the polygon mirror 28.
Since the polygon mirror 28 is rotated at a predetermined rotation speed by the polygon mirror driving circuit 29, when pulse light is incident on a reflecting mirror surface provided on the outer peripheral surface of the polygon mirror 28, the pulse light is scanned within a set angle. The scanned pulse light is projected toward the road surface 22 through the irradiation window 33 of the axle detection device 21. This axle detection device 2
As shown in FIG. 5, 1 is installed on the roadside 23 so as to scan a pulse light along a transverse direction of a road at a toll collection point of a toll road or the like.

The scanning direction of the pulse light emitted from the axle detecting device 21 is detected by a scanning direction detecting section. The scanning direction detector is constituted by an encoder 34 provided on the polygon mirror 28. The encoder 34 detects the rotation angle of the polygon mirror 28 to detect the scanning direction of the pulse light, and outputs the detection signal to the controller 30. And the tire detection circuit 35.

The light receiving section is a one-dimensional position detecting element (PSD)
, A light receiving lens 37, an optical filter 38, a current / voltage conversion circuit (I / V) 39, and an amplifier circuit 40 for noise reduction. When the pulse light projected on the road surface side as described above is reflected by an object such as the road surface 22 or the passing vehicle 24, the reflected pulse light is again passed through the irradiation window 33 as shown in FIG. After being incident on the inside 21 and being reflected by the polygon mirror 28,
The light is also reflected by the reflection mirror 31, passes through the light receiving lens 37 and the optical filter 38, and is received by the light receiving element 36. When the light receiving element 36 receives the pulse light and a light receiving current flows through the light receiving element 36, the light receiving current is converted into a current / voltage conversion circuit 39.
And is amplified by the amplifier circuit 40.

The distance calculation section includes a monitor circuit 41 for monitoring the driving of the light emitting element 25, a start signal generation circuit 42, a stop signal generation circuit 43, a time difference / voltage conversion circuit 44,
It comprises an analog / digital conversion circuit (A / D) 45 and a digital processing circuit 46.

As described above, when the light emitting element driving circuit 27 drives the light emitting element 25 according to the driving command from the controller 30, the driving current of the light emitting element driving circuit 27 generated for each pulse emission is monitored by the monitor circuit 41. You. The start signal generation circuit 42 generates a start signal each time the light emitting element 25 emits a pulse based on the monitor signal received from the monitor circuit 41. The start signal generated by the start signal generation circuit 42 is input to the time difference / voltage conversion circuit 44.

On the other hand, when the light receiving element 36 receives the pulse light, a stop signal is generated by the stop signal generating circuit 43 based on the voltage signal amplified by the amplifier circuit 40, and the stop signal is stopped every time each pulse light is received. The signal is supplied from the signal generation circuit 43 to the time difference / voltage conversion circuit 44.

The time difference / voltage conversion circuit 44 detects a time difference between the start signal and the stop signal of the same pulse light, and outputs a voltage signal corresponding to the time difference. Time lag/
The voltage signal output from the voltage conversion circuit 44 is converted to a digital signal by an A / D conversion circuit 45 and then sent to a digital processing circuit 46. The digital processing circuit 46 calculates a distance from the axle detection device 21 to a reflection position on the road surface 22 or the vehicle 24 based on the signal based on the principle of triangulation. As described above, if the distance from the axle detection device 21 to the reflection position is measured by measuring the time from the emission of the pulsed light to the reception of the pulsed light, the distance calculation can be performed quickly and easily, and the axle The detection device 21 is downsized,
Cost can be reduced.

The tire detecting section comprises a tire detecting circuit 35. The tire detection circuit 35 uses the distance information to the reflection position obtained by the digital processing circuit 46 and the data of the light projection direction calculated based on the detection signal from the encoder 34 (scanning direction detection unit) to perform reflection. The position distribution (profile) is calculated, and the tire 4
8 and the result of the determination is given to the input / output circuit 47.
The input / output circuit 47 assumes that the detection of the tire 48 has detected the axle of the passing vehicle 24, and exchanges the determination result with an external device.

More specifically, the detection principle of the tire 48 in the tire detection circuit 35 is based on the fact that the road surface 22
Is determined to be the tire 48.
FIGS. 8A, 8B, and 8C show distributions (profiles) of the reflection positions of the pulse light detected by the axle detection device 21 along the road crossing direction. In the case of FIG. 8A, since there is data that is perpendicular to the road surface 22 and is in contact with the road surface 22, it is determined that the vehicle is located at the tire position of the vehicle 24. In the case of FIG. 8B, since there is no data at a certain height or higher from the road surface 22, it is determined that the vehicle is on the road surface 22. In the case of FIG. 8C, data perpendicular to the road surface 22 exists, but since the data perpendicular to the road surface 22 appears discontinuously from the road surface 22, it is determined that the data is data on the vehicle body 49. . 8A, 8B and 8C, the number of tires of the passing vehicle 24, that is, the number of axles of the vehicle 24 is monitored. Can be detected.

Further, the axle detection device 21 of the present invention is a device having the above-described configuration for axle detection with improved axle detection accuracy. That is,
In the situation where it is most difficult to detect the tire 48, the passing vehicle 24
Is set to be able to detect the passing vehicle 2
No. 4 tire 48 can be reliably detected, and the axle detection accuracy is improved. The configuration for this will be specifically described below.

Considering the situation where the detection of the tire 48 is most difficult, the case where the vehicle 24 passes through the position farthest from the axle detecting device 21 at a high speed is considered. That is, when the vehicle 24 passes through the end opposite to the installation side of the axle detection device 21 as shown in FIG. 9, the distribution of the reflection positions on the tire 48 becomes the coarsest. Therefore, as shown in FIG. 9, the road width is set to L, and the vehicle 24 having the vehicle width W passes the position farthest from the axle detecting device 21 installed on the road side 23 of this road at the vehicle speed V [m / sec]. Then At this time, the distance from the light projecting unit of the axle detection device 21 to the tire 48 is D [m] (D> LW), and the light emission interval angle (1) of the pulse light projected from the axle detection device 21
The angle change in the light projection direction within the pulse cycle time) is Δθ [r
ad], the interval Δh [m] between the reflection positions of the pulse light projected from the axle detection device 21 on the tire 48
Can be approximately expressed as Δh = D · Δθ as can be seen from FIG.

In order to increase the detection accuracy of the tire 48, as shown in FIG. 10, the interval Δh between the reflection positions of the pulse light is set to the sectional height H of the tire 48 (the outer periphery of the tire 48 outside the wheel 50). (The value obtained by subtracting the inner radius from the radius). That is, Δh <H may be set. In particular, if the reflection position (irradiation point of the pulse light) on the tire 48 is required to be M points or more, Δh <(H / M) or D <{H / (MΔθ)} may be set.

Further, the tire 48 by the axle detecting device 21
Is to determine that there is a tire 48 by detecting a portion of the vehicle 24 that is in contact with the road surface 22 as described above. Therefore, assuming that the number of times of pulse light scanning necessary for determining the tire 48 of the running vehicle 24 is N, the condition for detecting the tire 48 of the vehicle 24 passing at the speed V [m / sec] is as follows. , The number of scanning lines included in a portion where the tire 48 is in contact with the road surface 22 (hereinafter, referred to as a tire contact portion) is N or more.

As shown in FIG. 11, when the length of the tire contact portion is A, the time required for the tire contact portion to pass through the scanning position of the pulse light is A / V [sec]. Assuming that the time required for one scan of the pulsed light to be scanned is T [sec], the pulsed light (A / V) is applied to the tire contact portion of the vehicle 24 passing at the speed V [m / sec] as shown in FIG. ) / T = A / (VT) scans. If this is N times or more, the tire 48 can be determined, and the condition for determining the tire 48 of the vehicle 24 passing at the speed V [m / sec] is expressed by the following equation. NVT <A ...

Further, assuming that one pulse cycle time (pulse light emission time interval) of the pulse light is Δt and angle change in the light projection direction in one scan of the pulse light (scan range of the pulse light) is θt, T = (θt / Δ) between the time required for one scan T and the light emission interval angle Δθ of pulsed light.
θ) Δt. Here, using the above equation,
This relationship can be written as: T = (D · θt · Δt) / Δh By substituting this equation into the above equation and rearranging it, the following equation is obtained. D <(A · Δh) / (N · V · θt · Δt) In particular, in order to detect the tire 48, it is sufficient that at least one scan can be performed on the tire 48, and if N = 1, this equation becomes: It is represented by the following equation. D <(A · Δh) / (V · θt · Δt)

Accordingly, from the tire position of the vehicle 24 passing on the road end near the axle detection device 21, the tire 4 of the vehicle 24 passing on the road end far from the axle detection device 21 is determined.
Up to 8, after determining the scanning range θt so that the pulsed light is scanned, assuming the upper limit speed V of the vehicle 24 passing through the toll gate on the toll road, the above equation or the above equation and the above equation are satisfied. If the distance D is determined and the axle detection device 21 is installed at that position, the tires 48 of the vehicle 24 passing at an end farther from the axle detection device 21 at high speed can also be accurately detected, and the axle detection device 21 can improve the tire detection performance.

Further, if the distance D is shortened in this configuration, the light projecting portion of the axle detecting device 21 is inevitably provided at a low position, so that the pulse light has a height that does not enter the eyes of the vehicle driver. This gives the driver a sense of security and keeps the driver safe.

(Second Embodiment) According to the axle detecting device 21 having the above configuration, the detection accuracy of the tire 48 or the axle can be improved. However, when the vehicle 24 passes at a higher speed than expected, or in bad weather,
Due to a cause such as contamination of the irradiation window 33, a case where the tire 48 cannot be detected or a case where the determination of the tire 48 is unclear may occur. For example, as shown in FIG. 12A, it is intermediate data between the data of the road surface 22 [FIG. 8B] and the data of the tire 48 [FIG. 8A], and it is difficult to distinguish any of them. In this case, as shown in FIG.
There is a large variation in the data at the position, and it is difficult to discriminate any of them. In such a case, tire 4
If one of the signals indicating the presence / absence of the number 8 is always output, there is a possibility that erroneous processing such as billing based on erroneous detection may be caused.

To cope with such a problem, the tire 4
In addition to the signal indicating the presence / absence of the tire 8 (or the axle), a signal indicating that the determination of the presence / absence of the tire 48 is unknown may be output to the external device. The unknown signal may be output from the same signal line as the signal indicating the presence or absence of the tire 48 or may be output from a different signal line. When the axle detection device outputs a signal indicating that it is not possible to determine the presence or absence of a tire, the type of the vehicle 24 cannot be determined from the number of axles, but the higher system (for example, a toll road toll collection system) ) Is based on data such as the length and height of the vehicle 24 which are separately detected by sensors.
It is possible to determine a vehicle type such as an ordinary car, a truck, and a trailer, and calculate a fee.

In the case of an application in which overcounting of the number of axles is a problem, it is determined that there is no tire if the discrimination is unknown. In the case of an application in which axle miscounting is a problem, the discrimination is made. If unknown, it may be determined that there is a tire.

(Third Embodiment) FIG. 13 is a schematic view showing an optical system of an axle detecting device according to still another embodiment of the present invention. In this axle detection device, a light receiving section including a light receiving element 36 and a light receiving lens 37 and a light emitting section including a light emitting element 25 and a light projecting lens 26 are arranged in parallel, and the central axis of the light receiving field of the light receiving section is projected. It is configured to be parallel to the optical axis of the pulse light projected from the light section.

The light-receiving field is determined by the focal length of the light-receiving lens and the size of the light-receiving element. Even in an optical scanning type axle detector having a conventional structure, the light-receiving field can be enlarged by shortening the focal length of the light-receiving lens. However, in order to increase the amount of reflected light received, it is necessary to increase the lens diameter, and it is difficult to shorten the focal length of the light receiving lens. Therefore, in the conventional axle detection device, FIG.
As shown in (2), in order to widen the light-receiving field, a plurality of light-receiving portions including the light-receiving element 11 and the light-receiving lens 12 have been required.

On the other hand, according to the axle detecting device having the structure as in the present embodiment, it is possible to provide a plurality of light receiving portions without providing a plurality of light receiving portions.
The detection area can be expanded, and the size and cost of the axle detection device can be reduced.

(Fourth Embodiment) FIG. 15 is a schematic view showing an optical system of an axle detecting device according to still another embodiment of the present invention. In this embodiment, the polygon mirror 2
8 are provided with a plurality of reflecting mirror surfaces 28a and 28b having different inclinations with respect to the rotation axis. According to such a polygon mirror 28, the reflection mirror surfaces 28a, 28 having different inclinations are provided.
Since the emission direction of the light scanned in 8b is shifted in the direction orthogonal to the light scanning direction, the pulse light can be scanned along a plurality of scanning lines as in the axle detection device 50 shown in FIG. .

Therefore, as shown in FIG. 16, the tire 48 of the passing vehicle 24 can be scanned with the pulse light along a plurality of scanning lines, and the time at which the tire 48 is present at each scanning position is determined. Based on the target change, it can be determined whether the vehicle 24 is stopping, moving forward, or moving backward. More specifically, when the vehicle 24 is moving forward, the presence of a tire is detected on the rear scanning line S2, and then the presence of the tire is detected on the front scanning line S1. Then, it is determined that the vehicle 24 has passed the detection area when the rear scanning line S2 has no tire and the front scanning line S1 has no tire. When the vehicle 24 is moving backward, the order is the reverse of that in the case of moving forward, and the scanning line S
At 1, the presence of a tire is detected, and then the rear scanning line S2 becomes the presence of a tire. Therefore, whether the vehicle 24 is moving forward due to the difference between the detection timings of the front and rear scanning lines S1 and S2,
It can be determined whether the vehicle is moving backward.

In this way, if the backward travel can be determined, when the tire 48 passes through the detection range of the axle detecting device 50 due to the reverse travel, the number of axles will not be mistaken by counting the number of tires. Further, when the vehicle is moved forward after moving backward, the same tire 48 can be prevented from being counted again.

As a method of scanning the pulse light along a plurality of scanning lines, as shown in FIG. 17, a plurality of light projecting units including a light emitting element 25 and a light projecting lens 26 may be provided. .

(Fifth Embodiment) In an optical scanning type axle detecting device, as shown in FIG. 18, the scanned pulse light is reflected by the exhaust gas 52 of the vehicle 24 near the road surface, and the reflected light is reflected. The light may be erroneously detected as the tire 48 or the axle.

FIG. 19 is a schematic diagram showing a configuration of an axle detecting device 61 according to still another embodiment of the present invention, in which an erroneous detection by the exhaust gas 52 is prevented. In this embodiment, the light emitter 63 and the light receiver 64
And a vehicle detection device such as a transmission type photoelectric sensor including a light transmitter 63 on one road side 23 across the road.
And a light receiver 64 is installed on the other roadside 23 so as to face the light emitter 63. Light emitter 63 and light receiver 64
Is installed at a position which is sufficiently higher than the position of the exhaust muffler of the passing vehicle 24 and lower than the height of the vehicle 24, and the light beam emitted from the light projector 63 is (The components other than the vehicle detection device, for example, components as shown in FIG. 6) are installed so as to be included in substantially the same vertical plane as the pulsed light scanned from the components. For example, in the example shown in FIG. 19, a light transmitter 63 is installed on a box body of the axle detection device main body 62, and a light receiver 64 is installed on a support 65, and a light transmitter 64 is provided above the pulse light for tire detection. A projection light beam is emitted from 63.
Therefore, according to the vehicle detection device, the presence or absence of the vehicle 24 can be detected without detecting the exhaust gas 52 of the vehicle 24.

In the vehicle detection device, when the vehicle 24 is not passing, the light beam emitted from the light projector 63 is incident on the light receiver 64, and the amount of light received by the light receiver 64 becomes greater than the threshold value. It outputs a no-vehicle signal (off). When the vehicle 24 is passing, the light beam emitted from the light projector 63 is blocked by the vehicle 24, and the vehicle presence signal (on) is output while the light reception amount remains below the threshold value. On the other hand, the axle detection device main body 62 outputs an axle presence signal (on) when the tire 48 is detected, and outputs an axle absence signal (off) when the tire 48 is not detected. The tire detection circuit 35 of the axle detection device main body 62 calculates the logical product (logical product with on = 1, off = 0) of the output of the vehicle detection device and the output of the axle detection device main body 62, and detects the result of the axle detection. The output is finally output to an external device.

That is, in this embodiment, FIG.
As shown in FIG. 0, when the axle detection device main body 62 detects the presence or absence of the tire 48 (S1) and the vehicle detection device detects the presence or absence of the vehicle 24 (S2), the axle detection device main body 6
2 detects the tire 48 and outputs the axle presence signal (on), and the vehicle detection device detects the vehicle 24 and outputs the vehicle presence signal (on), and outputs the final axle detection output to the axle. Output to the outside as existence (on) (S3, S
4) Otherwise, the axle detection output is axle off (off)
Is output to the outside (S3, S5).

According to this determination method, when the axle detecting device main body 62 detects the tire 48, the axle detecting device main body 62 outputs an axle presence signal (on), and the vehicle detecting device Since the presence signal (on) is output, the axle detection output becomes axle presence (on).

On the other hand, as shown in FIG. 18, when the axle detector main body 62 detects the exhaust gas 52, the axle detector main body 62 outputs an axle presence signal (on). Since the detection device outputs the no-vehicle signal (off), the axle detection output becomes no axle (off), and erroneous detection is prevented.

Of course, when the vehicle 24 is not passing or when the tire 48 is not detected even when the vehicle 24 is passing, the axle detection output is off (no axle).

Therefore, according to such an embodiment, it is possible to improve the detection accuracy of the tire 48, eliminate erroneous detection of the tire 48 due to the exhaust gas 52, and provide the vehicle detection function to the axle detection device 61. Can be added.

As the vehicle detection device, a sensor using ultrasonic waves or millimeter waves can be considered in addition to an optical sensor such as a photoelectric sensor. However, since sensors using ultrasonic waves or millimeter waves have a wide directivity, the vehicle is detected even immediately after the vehicle has passed the front of the vehicle detection device. For this reason, when the exhaust gas discharged behind the vehicle is present in the detection area of the axle detection device main body, the axle detection device erroneously detects the exhaust gas, and generates ultrasonic waves and millimeter waves that are the vehicle detection device. The used sensor also detects the vehicle after passing. Therefore, in order to eliminate erroneous detection of exhaust gas, it is necessary to use an optical sensor such as a photoelectric sensor.

(Sixth Embodiment) FIG. 21 is a schematic diagram showing a configuration of an axle detecting device according to another embodiment capable of preventing erroneous detection due to exhaust gas. In this embodiment,
Instead of a transmission type vehicle detection device, a vehicle detection device such as a regression reflection type optical sensor is provided. The vehicle detection device is
A vehicle detection device main body 67 having a built-in light emitter and a light receiver includes a regression reflection plate 68, and the vehicle detection device main body 67 is installed at a position where the upper part of the vehicle 24 can be detected, such as on a box of the axle detection device main body 62, The retroreflective plate 68 is on the opposite roadside 2
3 is installed on the support 65. In this vehicle detection device, when the vehicle 24 is not passing, the light beam emitted from the light projector in the vehicle detection device main body 67 is recursively reflected by the regression reflection plate 68 and returns to the original direction. The light is received by the light receiving device in the main body 67, and the light receiving amount of the light receiving device becomes equal to or more than the threshold value, and the vehicle detecting device main body 67 outputs the vehicle absence signal (off). When the vehicle 24 is passing, the light beam emitted from the light emitter in the vehicle detection device main body 67 is blocked by the vehicle 24, the amount of light received by the light receiver becomes less than the threshold value, and the vehicle presence signal (on) Is output. Then, the axle presence signal (o
n) or AND with the axle-less signal (off), and finally output the axle detection output to the outside. Therefore, also in this embodiment, erroneous detection of the tire 48 due to the exhaust gas can be prevented.

When a transmission type vehicle detection device is used as in the fifth embodiment, wiring work is required on both the roadside on the light emitter side and the roadside on the light receiver side. If a retro-reflective vehicle detection device is used, a retro-reflection plate 68 only needs to be installed on the opposite side of the vehicle detection device main body 67. Since it is on the roadside 23, the wiring work can be performed only on one roadside 23, and labor and wiring can be saved in the wiring work.

(Seventh Embodiment) FIG. 22 is a schematic diagram showing a configuration of an axle detecting device 69 according to still another embodiment of the present invention. In this embodiment, a plurality of vehicle detection device bodies 67a, 67b, 67c such as photoelectric sensors are installed at a height at which the vehicle 24 can be detected without being hindered by exhaust gas. FIG. 22 shows a regression reflection type vehicle detection device, but it may be a transmission type. The plurality of vehicle detection device main bodies 67a, 67b, 67c are arranged horizontally along the passing direction of the vehicle 24 and installed horizontally.

Now, the three vehicle detection device bodies 67a, 6
7b, 67c are installed, and when the vehicle 24 enters the detection area, the vehicle detection device main body 67a,
67b and 67c detect the vehicle 24 in order. The detection time difference t12 between the vehicle detection device bodies 67a and 67b is measured, and the detection time difference t23 between the vehicle detection device bodies 67b and 67c is measured.
Is measured, and the average value of the time differences t12 and t23 is referred to as ta.
ve [for example, (t12 + t23) / 2]. Assuming that the vehicle detection device bodies 67a, 67b, 67c are installed at equal intervals B, the passing speed of the vehicle 24 can be obtained as B / t ave. The vehicle passing speed B / t ave is a predetermined speed, for example, 30
At km / h or more, the detection accuracy of the axle is increased.
For example, the axle detection device main body 62 scans two pulsed light beams, or shortens the light emission pulse period of the light projecting unit in the axle detection device main body 62 to improve the axle detection accuracy. Therefore, according to this embodiment, erroneous detection due to exhaust gas can be prevented, and the tire 48 can be detected with a detection accuracy corresponding to the passing speed of the vehicle 24.

In this embodiment, the axle detecting device 6
9 is buried in the concave portion 70 of the roadside 23, thereby lowering the position of the light emitting portion of the axle detecting device main body 62.

(Eighth Embodiment) FIG. 23 is a block diagram showing a configuration of an axle detecting device 71 according to still another embodiment of the present invention. The configuration of the axle detection device main body 62 shown here is the same as that of the axle detection device shown in FIG. The vehicle detection device is of a retroreflective type,
2. It comprises a light receiver 73, a control determination processing circuit 74 and an input / output circuit 75. The input / output circuit 47 of the axle detection device main body 62 and the input / output circuit 75 of the vehicle detection device main body 67 are capable of bidirectional communication.
Is sent to the controller 30 of the axle detection device main body 62 via the input / output circuit 47.

Controller 30 of axle detector main body 62
Monitors the presence or absence of the vehicle 24 in the detection area based on the output from the vehicle detection device main body 67. And
The controller 30 drives the light emitting element drive circuit 27 to cause the light emitting element 25 to emit pulse light only when the output of the vehicle detection device main body 67 indicates that there is a vehicle.

With such a configuration, the axle detecting device main body 62 can perform the operation of detecting the tire 48 by causing the light emitting element 25 to emit light only when the vehicle 24 enters the detection area. The life of the light emitting element 25 can be prolonged, and power can be saved.

(Ninth Embodiment) In a toll gate on a toll road or the like, the axle detecting device 76 is connected to the vehicle detecting sensor 7.
7 is often installed side by side. FIG. 24 shows an axle detecting device 76 in such an installation state.
A retro-reflective sensor 77 is installed beside the axle detecting device 76, and a retro-reflective plate 78 vertically long is installed on the other roadside 23 so as to face the sensor 77. The vehicle detection sensor 77 emits a detection beam and vertically scans vertically to perform vehicle detection in the vertical direction.

The axle detecting device 76 incorporates the light projecting portion and the light receiving portion of the main body 67 of the retroreflective type vehicle detecting device.
There is no special retroreflector. The light beam is emitted from the vehicle detection device toward the regression reflection plate 78 of the vehicle detection sensor 77, and the light beam reflected by the regression reflection plate 78 is received.

According to such an embodiment, the retroreflector 78 of the vehicle detection sensor 77 is used, and a dedicated retroreflector is not required. The construction can be simplified and the cost can be reduced.

(Embodiment 10) For example, as in the embodiment shown in FIG. 19, when the vehicle detection device is set to be close to the height of the body of an ordinary passenger car, depending on the vehicle type (for example, a sports car type vehicle). May not be able to detect the vehicle because the light beam does not hit the vehicle body.

FIG. 25 is a schematic diagram showing the configuration of an axle detecting device 79 according to still another embodiment of the present invention, which is designed to reliably detect a vehicle 24 having a low vehicle height. This embodiment is characterized in that a light beam for vehicle detection is projected above the road surface 22 through which the vehicle 24 passes and lower than the bottom surface of the vehicle body 49 of the passing vehicle 24. I have. For example, one roadside 23
The vehicle detection device main body 67 is accommodated so as to be embedded in the concave portion provided in the vehicle, and the regression reflection plate 68 is provided on the side surface of the other roadside 23 so as to face the vehicle detection device main body 67.

In the vehicle detecting device 79, when the passing vehicle 24 does not exist, the light beam emitted from the light projecting portion of the vehicle detecting device body 67 is reflected by the regression reflection plate 68 and then detected by the vehicle. The light is received by the light receiver of the apparatus main body 67, and if the amount of received light at that time is equal to or larger than the threshold value, it is determined that there is no vehicle, and a vehicle absence signal (off) is output. On the other hand, when the vehicle 24 is passing, the light projection beam is shielded by the tire 48, so that at that moment, the amount of received light becomes equal to or less than the threshold value. Is output.

Moreover, in this vehicle detection device, the vehicle 24
When the tire 48 completely shuts off the light, the amount of light received by the light receiving unit decreases and is output with the axle (on). However, the light beam is attenuated by passing the exhaust gas, and the amount of light received by the light receiving unit No axle even if decreases
The threshold value of the amount of light received by the light receiving element 36 is set so that f) is output. Tire 4 at exhaust gas position
8 does not exist, also in this embodiment, the output of the vehicle detection device main body 67 and the output of the axle detection device main body 62 are logically ANDed to finally determine the presence or absence of the axle. 48 can be prevented from being erroneously detected. Further, regardless of the type of the vehicle 24, the vehicle 24 can be reliably detected, and the detection accuracy of the axle is further improved.

In this embodiment, a similar effect can be obtained by using a transmission type vehicle detection device such as a transmission type photoelectric sensor.

(Eleventh Embodiment) In the axle detection device as in the tenth embodiment, when dust such as dead leaves is accumulated on the road surface in front of the vehicle detection device, the vehicle detection device outputs a signal indicating that the vehicle is present. Continue to output. Also in this case, if the final judgment is made after calculating the logical product of the output of the vehicle detection device main body and the output of the axle detection device main body, there is no possibility of erroneously detecting the axle other than the exhaust gas. However, in the tenth embodiment, when dead leaves or the like are stacked in front of the vehicle detection device, there is a risk that exhaust gas may be erroneously detected as a tire.

The axle detecting device 80 shown in FIG. 26 is intended to eliminate such a possibility of erroneous detection, and has an axle having a light projecting portion 81 and a light receiving portion at a position higher than the vehicle detecting device main body 67. The detection device main body 62 has a function of determining the presence or absence of an object on the road surface 22. That is, the axle detection device 80 detects the road surface 2 at each scanning angle.
2 (that is, the profile of the road surface 22). When any object is present on the road surface 22, the distance is always shorter than the distance to the road surface 22 stored in the axle detection device main body 62. Therefore, the distance between the detected distance and the distance between the stored road surface 22 is determined. When the difference is equal to or larger than the set value, it can be determined that an object exists on the road surface 22.

According to this axle detection device, if the vehicle detection device 80 can detect an object on the road surface 22 by the axle detection device main body 62 while detecting the object other than the vehicle, Since it is determined that the light beam of the vehicle detection device 80 is blocked by dead leaves and dust, a signal for urging the cleaning of the road surface 22 is output, for example. On the other hand, if the axle detection device main body 62 cannot recognize any object on the road surface 22 even though the vehicle detection device 80 detects some object, it is an abnormality of the vehicle detection device. Therefore, the axle detection device 80 outputs a signal to notify the abnormality to the host system.

(Twelfth Embodiment) FIG. 27 is a schematic diagram showing a configuration of an axle detecting device 82 according to still another embodiment of the present invention. This is obtained by adding the function of the vehicle detection device to the axle detection device main body 62. That is, the axle detection device 82 includes the axle detection device main body 62 and the light receiver 8.
And 3. The light receiver 83 is installed on the support 84 at a height that can detect the vehicle 24 (that is, a position higher than the vehicle body bottom surface and lower than the vehicle height of the passing vehicle) on the roadside 23 opposite to the axle detection device main body 62. Have been. The light projecting unit 81 of the axle detecting device main body 62 is
And the light projecting unit 81 performs a pulse scanning at a large scanning angle from the tire position of the vehicle 24 passing closest to the light emitting device 83 to a level at which pulse light is emitted substantially horizontally. Scans light.

In the scanning range where the pulse light is irradiated toward the road surface 22, the axle detecting device main body 62 detects the tire 48, and emits the pulse light almost horizontally toward the light receiver 83. If so, the passing vehicle 24 is detected. That is, when the vehicle 24 is not passing, the light receiving unit 83 has a light receiving amount equal to or larger than the threshold value when the pulse light is emitted from the axle detecting device main body 62 substantially horizontally, and the vehicle absence signal (off) Is output. Alternatively, if the vehicle is passing through the vehicle, the light receiver 83 outputs the vehicle presence signal (on) because the light reception amount does not exceed the threshold value. When the tire 48 is detected, the light receiving section in the axle detection device main body 62 outputs an axle presence signal (on). The output of the light receiver 83 and the output of the axle detector main body 62 are ANDed to determine whether or not the tire is finally detected, thereby preventing erroneous detection due to exhaust gas. That is, when exhaust gas is exhausted in the detection area, the axle detection device main body 62 erroneously detects the exhaust gas in the detection area as an axle, and outputs a signal (on) indicating that there is an axle.
However, since the exhaust gas is exhausted behind the vehicle, the output of the photodetector 83 at this time becomes no vehicle (off),
The logical product does not finally detect the axle (off)
Is output, and erroneous detection is avoided.

According to such an axle detecting device, since the light projecting portion 81 of the axle detecting device main body 62 also functions as the light emitting device of the vehicle detecting device, the configuration is simplified and the cost can be reduced. In this embodiment, the vehicle detection method is as follows.
It may be a retroreflective type.

(Thirteenth Embodiment) FIG. 28 is a schematic diagram showing a configuration of an axle detecting device 85 according to still another embodiment of the present invention. In this embodiment, similarly to the twelfth embodiment, the light projecting unit 81 of the axle detection device main body 62 also serves as the light projector of the vehicle detection device main body. In this embodiment, of the pulse light scanned by the axle detection device main body 62, the pulse light scanned toward the road surface 22 is used for tire detection, and the pulse light emitted downward from the axle detection device main body 62 is used. Is used for vehicle detection. That is,
The pulse light emitted downward from the axle detection device main body 62 is reflected by a reflecting mirror 86 installed at a position lower than the upper surface of the roadside 23.
By reflecting the light, the light is emitted in parallel with the road surface 22,
The light is received by a light receiver 87 installed in the other roadside 23. When the vehicle passes, this pulse light is blocked by the tire 48 of the vehicle 24 and is not received by the light receiver 87. A vehicle presence signal (on) is output.

Also in this axle detection device 85, it is determined whether or not the tire 48 has been finally detected by taking the logical product of the output of the light receiver 87 and the output of the axle detection device main body 62, False detection is prevented. In addition, since a separate projector for vehicle detection is not required, the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a conventional tread plate type axle detection device.

FIG. 2 is a schematic diagram showing a conventional optical scanning axle detection device.

FIG. 3 is a diagram illustrating a state in which the tire is detected by scanning the tire with laser light in the axle detecting device according to the first embodiment.

FIG. 4 is a diagram showing irradiation points of laser light scanned along a tire.

FIG. 5 is a schematic perspective view of an axle detection device according to an embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of the axle detection device according to the first embodiment.

FIG. 7 is a diagram showing a state in which the axle detection device emits pulsed light toward a tire of the vehicle.

FIGS. 8A, 8B, and 8C are diagrams for explaining the principle of determining a tire, a road surface, and a vehicle body;

FIG. 9 is a diagram showing definitions of physical quantities used to determine an installation position of the axle detection device according to the first embodiment.

FIG. 10 is a diagram showing irradiation points of pulse light on a tire.

FIG. 11 is a diagram for explaining a relationship between a vehicle passing at a high speed and a scanning line.

FIGS. 12A and 12B are diagrams showing data for which it is difficult to determine a tire.

FIG. 13 is a schematic diagram showing an optical system of an axle detection device according to still another embodiment of the present invention.

FIG. 14 is a diagram illustrating a problem of a conventional example.

FIG. 15 is a schematic diagram showing an optical system of an axle detection device according to still another embodiment of the present invention.

FIG. 16 is a perspective view showing a state of detecting a tire of the vehicle using the axle detection device of the above.

FIG. 17 is a schematic diagram showing another method for obtaining a plurality of scanning lines.

FIG. 18 is a diagram illustrating a state in which pulse light is reflected by exhaust gas and is erroneously detected as a tire.

FIG. 19 is a schematic view showing a configuration of an axle detecting device according to still another embodiment of the present invention.

FIG. 20 is a diagram showing an algorithm for judging the presence or absence of an axle in the embodiment.

FIG. 21 is a schematic diagram showing a configuration of an axle detection device according to still another embodiment of the present invention.

FIG. 22 is a perspective view showing a configuration of an axle detecting device according to still another embodiment of the present invention.

FIG. 23 is a block diagram showing a configuration of an axle detection device according to still another embodiment of the present invention.

FIG. 24 is a perspective view showing a configuration of an axle detecting device according to still another embodiment of the present invention.

FIG. 25 is a schematic view showing a configuration of an axle detecting device according to still another embodiment of the present invention.

FIG. 26 is a schematic diagram showing a configuration of an axle detection device according to still another embodiment of the present invention.

FIG. 27 is a schematic diagram showing a configuration of an axle detection device according to still another embodiment of the present invention.

FIG. 28 is a schematic diagram showing a configuration of an axle detection device according to still another embodiment of the present invention.

DESCRIPTION OF SYMBOLS 22 Road surface 23 Road side 24 Vehicle 25 Light emitting element 26 Light emitting lens 28 Polygon mirror 30 Controller 36 Light receiving element 37 Light receiving lens 48 Tire 52 Exhaust gas 62 Axle detector main body 63 Projector of vehicle detecting device 64 Vehicle detecting device Receiver 67 Vehicle detection device main body 68 Retroreflector

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shiro Ogata 10-Family Todocho, Hanazono-ku, Kyoto-shi, Kyoto 2F112 AA06 BA06 BA07 CA05 CA12 DA25 DA40 EA05 FA03 FA08 FA33 5H180 AA01 CC03 CC07 CC11 CC12 EE07 EE10

Claims (6)

[Claims] An optical scanning unit that scans a pulsed light toward a detection area; a scanning direction detection unit that detects a scanning direction of the pulsed light; and light scanned by the optical scanning unit and reflected at an irradiation point. A light receiving means for receiving light; a distance calculating means for calculating a distance to an irradiation point of each pulse light based on a light receiving signal in the light receiving means; information on a scanning direction obtained by the scanning direction detecting means; In an axle detection device including a tire detection unit that detects the presence or absence of a tire based on distance information to an irradiation point obtained by the distance calculation unit, it is assumed that the vehicle travels in a region farthest from the optical scanning unit in the detection region. On the tire of the vehicle, one of the pulsed light
An axle detection device, wherein the distance that the irradiation point moves in each pulse period is sufficiently smaller than the height of the tire cross section. 2. A method according to claim 1, wherein a distance to a tire of a vehicle assumed to travel in a region farthest from said optical scanning means in a detection region is D, and a minimum length of a tire portion that can be identified as a tire by optical scanning is A. The moving distance of the irradiation point for each pulse cycle of the pulse light on the tire of the vehicle is Δ
h, the scanning angle of the pulse light by the optical scanning means is θt,
When the assumed maximum speed of the vehicle passing through the detection area is V and one pulse cycle time of the pulsed light is Δt, the distance D satisfies D <(A × Δh) / (V × θt × Δt). The axle detection device according to claim 1, wherein 3. A pulse light is scanned toward a detection area,
Tire detecting means for determining the distance to each irradiation point based on the reflected light, detecting the presence or absence of a tire in a detection area from the distance information to the irradiation point and the scanning direction of each pulse light, and scanning the pulse light An axle detection device, comprising: vehicle detection means installed on or near the same plane as a surface and detecting the presence or absence of a vehicle in or near a detection area. 4. The vehicle detection means detects the presence or absence of a vehicle by reflecting light emitted toward a detection area by a regression reflection plate and receiving the reflected light. The axle detecting device according to claim 3, wherein the plate uses a retroreflective plate used for an existing or an attached sensor using the retroreflection. 5. The tire detecting means has a function of detecting the presence or absence of an object having a height equal to or higher than a predetermined height on a road surface, and a detection result obtained by the object detecting function of the tire detecting means and a detection result obtained by the vehicle detecting means. The axle detection device according to claim 3, wherein the abnormality of the vehicle detection means is detected based on the following. 6. A retroreflector or a photodetector is provided so as to face the tire detector, and among the pulsed light emitted from the axle detector toward the road surface and scanned, the retroreflector or the photoreceiver is provided. The axle detection device according to claim 3, wherein the presence or absence of the vehicle in the detection area can be detected by pulse light incident on the axle.