JP2007265003A - Tire width discriminating device, travelling direction discriminating device, and vehicle type discriminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve detection accuracy of a tire width, a traveling direction or the like which are elements required for discriminating a vehicle type. <P>SOLUTION: The tire width discriminating device has: a first step board 15a arranged obliquely to the traveling direction of a vehicle on a road surface of a driving lane; and a second step board 15b arranged in parallel to the first step board 15a. The device discriminates the tire width of the vehicle 10 traveling the driving lane, based on how a stepping detection period when stepping is detected by the first step board 15a is temporarily overlapped with the stepping detection period when stepping is detected by the second step board 15b. The tire width discrimination device comprises a correction part for correcting the stepping detection periods detected by the first step board 15a and the second step board 15b, and discriminates the tire width by using the stepping detection period after correction by the correction part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tire width discriminating device, a traveling direction discriminating device, and a vehicle type discriminating device having these devices, which are suitable for use in discriminating the type of a passing vehicle in a toll collection system on a toll road. .

  In recent years, as a toll collection system for toll roads, a non-stop automatic toll collection system (hereinafter referred to as “ETC (Electronic Toll Collection)”) that automatically collects tolls without temporarily stopping a traveling vehicle is becoming popular. Along with this, there has been a demand for further improvement in accuracy of a vehicle type discriminating apparatus that automatically discriminates the type of a vehicle entering the toll collection area.

Conventionally, as the vehicle type discriminating device, for example, the number of axles, the number of wheels, the tread (width between the left and right tires), the tire width, the vehicle width, etc. of the vehicle are measured by various sensors embedded in the road surface, etc. A technique for discriminating a vehicle type from a measurement result is known.
For example, in Patent Document 1, sensors (treads) that detect that a vehicle tire has been stepped on in the width direction of a road are juxtaposed at predetermined distance intervals, and the number of axles is detected based on the detection result of the sensor. Techniques to do this are disclosed.
Further, in Non-Patent Document 2, a long sensor for detecting the stepping by the tire of the vehicle is embedded in the road surface so as to be inclined with respect to the traveling direction of the vehicle, and the detection result by the stepping detection sensor is shown in FIG. Based on this, a technique for detecting the tire width, in other words, the number of tires per shaft, is disclosed.
JP 2001-351113 A “Q-FREE (registered trademark) Product Description MD1112 Automatic Vehicle Classifier”, [online], [searched March 7, 2006], Internet <http://www.nba.no/publish/products/avc/md1112. pdf>

  In the conventional inventions disclosed in Patent Document 1 and Non-Patent Document 2, sensors are embedded in the road surface, and the number of axles and tire width are determined based on sensor signals from these sensors. The sensor signal may be disturbed due to chattering or missing, and there is a problem that it is difficult to accurately detect tire treading.

  The present invention has been made to solve the above-described problem, and is a tire width determining device, a traveling direction determining device, and a tire width determining device capable of increasing detection accuracy such as a tire width and a traveling direction, which are elements necessary for vehicle type determination, and An object of the present invention is to provide a vehicle type discriminating apparatus capable of discriminating a vehicle type with higher accuracy using these devices.

In order to solve the above problems, the present invention employs the following means.
According to the present invention, a first step detection sensor that detects tire stepping is disposed on a road surface of a traveling lane obliquely with respect to the traveling direction of the vehicle, and in parallel with the first stepping detection sensor. , A second stepping detection sensor is disposed, and a stepping detection period in which stepping is detected by the first stepping detection sensor and stepping detection in which stepping is detected by the second stepping detection sensor. A tire width determination device for determining a tire width of a vehicle traveling in the travel lane based on a temporal overlap with a period, wherein the first step detection sensor and the second step detection sensor There is provided a tire width discriminating device that includes a correcting unit that corrects the stepping detection period detected by the correction unit, and that determines a tire width using the stepping detection period corrected by the correcting unit.

  According to such a configuration, since the correction means for correcting the step detection period detected by the first step detection sensor and the second step detection sensor is provided, for example, the sensor signal detected by these sensors. In addition, when signal disturbances such as chattering and loss occur, these signal disturbances can be corrected. As a result, the tire width can be determined based on a sensor signal without chattering or omission, so that the determination accuracy can be improved.

  In addition, signal disturbance as described above is likely to occur when the vehicle stays on the sensor for a longer time than usual, such as when there is a traffic jam, and more than two axles from the weight ratio of the vehicle. Therefore, the correction may be performed specifically for such a case. By doing so, correction can be performed efficiently.

  In the tire width determination device, the correction unit is configured such that a waiting period from the end of detection of one step detection period to the start of detection of a subsequent step detection period is set in advance as a first threshold value. In the following cases, the standby period may be included in the tread detection period.

  According to such a configuration, in the first sensor signal output from the first stepping detection sensor and the second sensor signal output from the second stepping detection sensor, the first threshold value is generated by chattering or the like. When the following waiting period (in other words, a period in which no treading is detected) occurs, correction is performed so that this waiting period is included in the treading detection period. It becomes possible to cancel. As a result, the tire width can be determined based on a highly accurate sensor signal, so that the determination accuracy can be improved.

  In the tire width determination device, the correction means has one step detection period not longer than a second threshold and a waiting period immediately before or immediately after the one step detection period not less than a third threshold. In this case, the one step detection period that is less than or equal to the second threshold value may be lengthened, and the waiting period that is greater than or equal to the third threshold value may be shortened.

  According to such a configuration, a loss or the like occurs in the first sensor signal output from the first stepping detection sensor and the second sensor signal output from the second stepping detection sensor. When the stepping detection period is less than or equal to the second threshold and the standby period is greater than or equal to the third threshold, correction is made to lengthen the stepping detection period and shorten the standby period. Thus, it is possible to eliminate signal disturbance due to signal loss. As a result, the tire width can be determined based on a highly accurate sensor signal, so that the determination accuracy can be improved.

  In the tire width determination device, the correction means detects the one stepping detected by the stepping detection sensor that has not detected the one stepping detection period that is equal to or less than the second threshold. The correction may be performed using a stepping detection period corresponding to a detection period and a standby period corresponding to a standby period that is equal to or greater than the third threshold.

According to such a configuration, the first sensor signal output from the first stepping detection sensor and the second sensor signal output from the second stepping detection sensor are equal to or less than the second threshold value. When one step detection period and a standby period equal to or greater than the third threshold are detected, correction is performed based on the sensor signal detected by the other step detection sensor. That is, since the first step detection sensor and the second step detection sensor are stepped on the same tire with a predetermined time difference, the first step detection sensor and the second step detection sensor There should be no noticeable difference in the sensor signals. Therefore, if chattering or loss of signal occurs in the sensor signal detected by one sensor, the correct sensor is obtained by performing correction based on the sensor signal detected by the other sensor. A signal waveform can be obtained.
Thereby, the disturbance of the signal due to the effect of the signal loss can be eliminated, and the tire width is determined based on the highly accurate sensor signal, so that the determination accuracy can be improved.

  In the tire width determination device, the second threshold value may be the first stepping time during a corresponding stepping detection period detected by a stepping detection sensor that has not detected the one stepping detection period. It is good also as setting to the value which multiplied the coefficient determined according to the arrangement | positioning relationship of an attachment detection sensor and a said 2nd stepping detection sensor.

  In the tire width determination device, the third threshold value may be the first step detection in a corresponding waiting period detected by a step detection sensor that has not detected the one step detection period. It is good also as setting to the value which multiplied the coefficient determined according to the arrangement | positioning relationship between a sensor and said 2nd stepping detection sensor.

  As described above, since the first step detection sensor and the second step detection sensor are stepped on the same tire with a predetermined time difference, the first step detection sensor and the second step detection sensor are the same. There should be no significant difference in the sensor signal with the detection sensor. Therefore, if there is a difference of a predetermined amount or more between the sensor signal detected by one sensor and the sensor signal detected by the other sensor, it is determined that the signal is disturbed, By correcting the location, a more accurate sensor signal can be obtained.

  In the tire width determination device, a stepping detection period in which stepping is detected by the first stepping detection sensor overlaps with a stepping detection period in which stepping is detected by the second stepping detection sensor. The tire width may be determined based on whether or not the overlap period is equal to or greater than the fourth threshold value.

  According to such a configuration, it is possible to eliminate the influence of the off-delay generated due to the characteristics of the first step detection sensor and the second step detection sensor, so that the tire width can be determined with high accuracy. Can be done.

  In the tire width determination device, the fourth threshold value may be set according to a traveling speed of the vehicle.

  According to such a configuration, since the fourth threshold value is set according to the traveling speed of the vehicle, it is possible to determine the tire width based on an appropriate value according to the traveling state of the vehicle. Thereby, the discrimination accuracy of the tire width can be further improved.

  According to the present invention, a third stepping detection sensor for detecting the stepping of the tire is disposed on the road surface of the traveling lane in a direction orthogonal to the traveling direction of the vehicle, and the third stepping detection sensor and A fourth step detection sensor is arranged in parallel, and the step detection period in which stepping is detected by the third step detection sensor and the step detection by which the step detection is detected by the fourth step detection sensor. A travel direction determination device for determining a travel direction of a vehicle traveling in the travel lane based on a travel detection period, wherein the travel detection period is greater than or equal to a fifth threshold value. And a correction means for providing a standby period so that each separated tread detection period becomes a maximum tread detection period determined according to the traveling speed of the vehicle, and after correction by the correction means How to advance the vehicle using the tread detection period Providing the traveling direction discriminating device for discriminating.

  According to such a configuration, when the sensor signals detected by the third stepping detection sensor and the fourth stepping detection sensor are combined with the stepping detection period due to occurrence of an off delay or the like. Since the tread detection period is divided into two, and further, a standby period is provided so that each separated tread detection period becomes the maximum tread detection period determined according to the traveling speed of the vehicle. It is possible to eliminate the above-described coupling due to the off-delay and restore each tread detection period. Thereby, it is possible to improve the accuracy of discrimination.

  The present invention provides a vehicle type discriminating device that includes the tire width discriminating device described above and discriminates the vehicle type of the vehicle using the discrimination result of the tire width discriminating device.

  According to such a configuration, since the vehicle type is determined based on the tire width determined with high accuracy, the accuracy of the vehicle type determination can be improved.

The present invention further provides a vehicle type discriminating device that includes the above-described tire width discriminating device and the above-described traveling direction discriminating device, and discriminates the vehicle type of the vehicle using the discrimination results by these devices.
According to such a configuration, since the vehicle type is determined based on the tire width and the traveling direction determined with high accuracy, it is possible to further improve the accuracy of the vehicle type determination.

  According to the present invention, a first step detection sensor that detects tire stepping is disposed on a road surface of a traveling lane obliquely with respect to the traveling direction of the vehicle, and in parallel with the first stepping detection sensor. , A second stepping detection sensor is disposed, and a stepping detection period in which stepping is detected by the first stepping detection sensor and stepping detection in which stepping is detected by the second stepping detection sensor. A tire width determination method for determining a tire width of a vehicle traveling in the travel lane based on a temporal overlap with a period, the first step detection sensor and the second step detection sensor There is provided a tire width determination method for correcting the stepping detection period detected by the step and determining the tire width using the corrected stepping detection period.

  According to the present invention, a third stepping detection sensor for detecting the stepping of the tire is disposed on the road surface of the traveling lane in a direction orthogonal to the traveling direction of the vehicle, and the third stepping detection sensor and A fourth step detection sensor is arranged in parallel, and the step detection period in which stepping is detected by the third step detection sensor and the step detection by which the step detection is detected by the fourth step detection sensor. A traveling direction determination method for determining a traveling direction of a vehicle traveling in the traveling lane based on a sticking detection period, wherein when the stepping detection period is equal to or greater than a fifth threshold, the stepping detection period Is divided into two, and a standby period is provided so that each separated tread detection period becomes a maximum tread detection period determined in accordance with the traveling speed of the vehicle. Providing a method for determining the direction of travel To.

  According to the present invention, it is possible to detect the number of tires per axle, which is an element necessary for vehicle type determination, the traveling direction, and the like with higher accuracy, and further, using these detection results, vehicle type determination can be performed. It can be performed with high accuracy.

An embodiment of a vehicle type identification device according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a vehicle type identification device according to an embodiment of the present invention. This vehicle type discrimination device is, for example, a device that is installed at a toll gate on a toll road and discriminates the vehicle type of a vehicle that has entered the toll gate.
As shown in FIG. 1, the vehicle type identification device according to the present embodiment detects passage of a vehicle 10 entering a measurement area A provided along a toll gate and measures the cross-sectional shape of the vehicle 10. An overhead sensor 11, a vehicle separator (vehicle separator) 13 for detecting the passage of the vehicle 10 following the overhead sensor 11, an imaging device 14 for imaging the license plate of the vehicle 10 that has entered the measurement area A, The number of tires per axle of the vehicle, in other words, a long first tread (first tread detection sensor) 15a and second tread (second tread detection sensor) for detecting the tire width. ) 15b, an elongated third tread (third tread detection sensor) 17a and fourth tread (fourth tread detection sensor) 17b for detecting the number of axes of the vehicle and the traveling direction; From these sensors Control apparatus for determining the vehicle type based on No. (refer to FIG. 4) are provided as main components.

  The overhead sensor 11 is installed in a gantry or the like located above the toll gate lane, and a detection unit (not shown) for measuring the distance to the vehicle 10 traveling in the toll gate lane is provided inside. Yes. The overhead sensor 11 detects and separates the vehicles 10 entering the measurement area A one by one based on whether or not the scanning surface 19 is blocked by the vehicle 10. Further, the vehicle width and height of the vehicle 10 are detected by measuring the distance to the vehicle 10 that blocks the scanning surface 19. Furthermore, while the vehicle 10 passes through the scanning surface 19, the distance to the vehicle 10 is measured several times and the shape of the vehicle 10 is recognized three-dimensionally. When the overhead sensor 11 detects the vehicle width, vehicle height, and three-dimensional shape of each vehicle 10, it outputs these detection results to the control device 20 (see FIG. 4) described later.

  The vehicle separator 13 is installed in front of the scanning plane 19 in the traveling direction of the vehicle 10 with a distance of 3.3 meters slightly longer than the maximum length of a light vehicle (including a motorcycle). The vehicle separator 13 includes a light emitting unit 13a that irradiates light in the width direction of the lane and a light receiver 13b that receives the light. The vehicle separator 13 detects the passage of the vehicle 10 when the light beam emitted from the light emitting unit 13 a is blocked by the vehicle 10, and outputs the detection result to the control device 20.

For example, the first tread plate 15a is installed on the road surface behind the vehicle separator 13 in the traveling direction of the vehicle 10 in a semi-embedded state obliquely with respect to the traveling direction of the vehicle. Further, the second tread 15b is installed in a semi-embedded state parallel to the first tread 15a at a predetermined distance d on the road surface ahead of the first tread 15a in the traveling direction of the vehicle. ing.
The distance d between the first tread plate 15a and the second tread plate 15b is determined by the following relational expression (1).

d = W + Ltanθ (1)
In the relational expression (1), d is a distance between the first tread plate 15a and the second tread plate 15b as shown in FIG. 2, W is a minimum ground contact width W of the tire that needs to be discriminated in the vehicle type discriminating device, L is the minimum contact length of the tire, and θ is the inclination θ with respect to the approach direction of the vehicle (tire).

The first tread plate 15a and the second tread plate 15b include, for example, electrical contacts disposed along the longitudinal direction inside a main body formed of a hard rubber material. Each electrical contact comes into contact with the electrical contact when the main body is stepped on the tire and compressed.
For example, as shown in FIG. 3, each of the first tread plate 15a and the second tread plate 15b is stepped on by a tire, so that “H (high)” is applied to the tire when the main body comes into contact with an electrical contact. When not stepped on and the main body is not in contact with the electrical contact, “L (low)” is output to the control device 20 as a sensor signal. In the present embodiment, the sensor signal from the first tread 15a is defined as the first sensor signal, and the sensor signal from the second tread 15b is defined as the second sensor signal. In each of these sensor signals, a period when the signal is “H (high)” is defined as a “stepping detection period”, and a period when the signal is “L (low)” is defined as a “standby period”.

The third tread 17a is installed, for example, in a semi-embedded state on the road surface R located immediately below the overhead sensor 11 in a direction perpendicular to the lane. The step board 17a is installed on the road surface ahead of the third step board 17a in the traveling direction of the vehicle at a predetermined distance from the third step board 17a and in a semi-embedded state in parallel.
The third and fourth treads 17a and 17b have, for example, the same configuration as the first tread 15a. When the main unit comes into contact with an electrical contact by being stepped on by a tire, the “H (high)” "Is not stepped on the tire and the main body is not in contact with the electrical contact," L (low) "is output as a sensor signal to the control device 20 (see FIG. 4). In the present embodiment, the sensor signal from the third tread 17a is defined as the third sensor signal, and the sensor signal from the fourth tread 17b is defined as the fourth sensor signal. In each of these sensor signals, a period when the signal is “H (high)” is defined as a “stepping detection period”, and a period when the signal is “L (low)” is defined as a “standby period”.

  A sensor (not shown) for detecting the tread of the vehicle is installed in a semi-embedded state in the vicinity of the third tread plate 17a and the fourth tread plate 17b. A signal from this sensor is sent to an axis number discriminating unit, which will be described later, and the tread is detected in the axis number discriminating unit. As the tread detection technique, a known technique can be appropriately employed.

As shown in FIG. 4, the control device 20 includes a tire width determining unit (tire width determining device) 21, an axis number determining unit 22, a traveling direction determining unit (traveling direction determining device) 23, and a vehicle type determining unit 24. .
The tire width discriminating unit 21 receives the first sensor signal and the second sensor signal, respectively, and discriminates the tire width according to the overlapping time of the ON times in these sensor signals. In the present embodiment, the tire width determination unit 21 includes a correction unit (correction unit) that corrects the first sensor signal and the second sensor signal, and the first sensor signal corrected by the correction unit and The tire width is determined using the second sensor signal. In the present embodiment, the tire width is divided into a 1-axis type and a 2-axis type. A single-shaft type has two tires per axis (one on the left and right), and a two-axis type has four or more tires per axis (two on the left and right) Say. For example, as illustrated in FIG. 5, the tire width determination unit 21 determines the shaft type 2 when an overlap is detected between the step detection period in the first sensor signal and the step detection period in the second sensor signal. If the overlap is not detected, it is determined that the shaft type is 1, and the determination result is output to the vehicle type determining unit 24.
The processing content in the tire width determination unit 21 is a main characteristic part of the present invention, and details will be described later.

The number-of-axis discriminating unit 22 receives the third sensor signal and the fourth sensor signal, respectively, detects the number of axles by detecting the number of rises in these sensor signals, and detects the detection result as the vehicle type discriminating unit 24. Output to.
Specifically, as shown in FIG. 6, the number-of-axis determination unit 22 detects “L (low)” in the third sensor signal while one vehicle is separated and detected by the vehicle separator 13. The number of axles is detected by detecting the number of rises to “H (high)”. In FIG. 6, rising is detected twice, and it is determined that the vehicle 10 has two axes.

The traveling direction determination unit 23 receives the third sensor signal and the fourth sensor signal, respectively. Based on the order of the “H (high)” periods in these sensor signals, the traveling direction of the vehicle, that is, the vehicle Whether the vehicle is moving forward or backward is detected, and the detection result is output to the vehicle type discriminating unit 24.
Specifically, as shown in FIG. 6, when “H (high)” is detected in the fourth sensor signal after “H (high)” is detected in the third sensor signal, Judge that it is moving forward. In addition, as shown in FIG. 7, when “H (high)” is detected in the third sensor signal after “H (high)” is detected in the fourth sensor signal, the vehicle moves backward. Judge that In the case of FIG. 7, since “H (high)” is first detected in the third sensor signal, “H (high)” is detected in the fourth sensor signal. After that, it is immediately recognized that he moved backwards.

The vehicle type discriminating unit 24 receives the shaft type from the tire width judging unit 21 described above, the number of shafts from the axis number discriminating unit 22, the traveling direction from the traveling direction discriminating unit 23, and a vehicle detection signal from the vehicle separator 13. The vehicle width, vehicle height, and three-dimensional shape of each vehicle 10 are input from the overhead sensor 11. An imaging result is input from the imaging device 14.
The vehicle type discriminating unit 24 normally discriminates the vehicle type by discriminating the display of the vehicle type described in the license plate of the vehicle 10 imaged by the imaging device 14, and the imaging device 14 cannot discriminate the vehicle type. Only in this case, the vehicle type is discriminated using the input signal from the overhead sensor 11 or the like.

  Hereinafter, the vehicle type discrimination process according to the present embodiment will be described with reference to FIG. FIG. 8 is a flowchart illustrating a processing procedure of vehicle type determination by the vehicle type determination unit 24.

  First, when one vehicle 10 is separated and detected by the overhead sensor 11 (step S1 in FIG. 8), the vehicle determination unit 24 determines that the number of axes is 2, 3, It is determined whether it is any of 4 or more (step S2). If the number of axes is 2, it is determined whether the axis type of the vehicle 10 is the axis type 1 or the axis type 2 based on the determination result of the tire width determining unit 21 (step SA3). As a result, when the shaft type is 1, it is determined whether the vehicle length of the vehicle 10 is less than 3.3 meters or more based on the detection results of the overhead sensor 11 and the vehicle separator 13 (step S4). Specifically, it is determined whether the vehicle length of the vehicle 10 is longer or shorter than 3.3 meters depending on whether the vehicle 10 is detected simultaneously with the overhead sensor 11.

  If the vehicle 10 is not detected by the overhead sensor 11 and the vehicle separator 13 at the same time, it is determined that the vehicle 10 is either a mini vehicle or a motorcycle, and the vehicle length is 3.3 meters. If it is more than the above, it is determined that the vehicle is a normal car, a small truck, or a small bus as “normal”.

  On the other hand, when the tire of the vehicle 10 is the shaft type 2 in step S3, the tread of the vehicle 10 is determined to be small, medium or large based on a signal from a tread detection sensor (not shown) (step S5). ). If the tread is small, the process proceeds to step S4, and the vehicle length is determined again. Based on this result, “total 2” or “normal” is determined. On the other hand, if the tread is in the middle in step S5, the vehicle 10 is determined to be “medium” as a medium truck, and if the tread is large, the shape of the vehicle body is determined based on the detection result of the overhead sensor 11. It is determined whether the track or the bus (step S6). If the vehicle body shape is a truck, the vehicle 10 is determined to be “large” as a large truck, and if the vehicle shape is a bus, the vehicle 10 is determined to be “extra large” as a large bus.

In step S2, if the number of axes of the vehicle 10 is 3, it is determined that the vehicle 10 is a large truck with three axes and is “large”.
In step S2, if the number of axes of the vehicle 10 is four or more, it is determined based on the detection result of the overhead sensor 11 whether the shape of the vehicle body is a single vehicle body or a plurality of vehicle bodies having a tow portion. (Step S7) If the vehicle is a single vehicle, the vehicle 10 is determined to be “large” because it is a four-axis large truck, and if it is a plurality of vehicles, it is determined to be “extra large” as a trailer.
The above-described vehicle type determination result is transmitted from the control device 20 to a higher-level device, and charging according to the vehicle type is performed here.

Next, the tire width determination unit 21 which is a main characteristic part of the present invention will be described in detail.
As described above, the tire width determination unit 21 according to the present embodiment receives the first sensor signal and the second sensor signal, respectively, and determines the tire width according to the overlap of the on-time in these sensor signals. Is. In addition, the tire width determination unit 21 includes a correction unit (correction unit) that corrects the first sensor signal and the second sensor signal.

  Specifically, the correction unit (not shown) determines that chattering has occurred when the standby period is equal to or less than a first threshold value set in advance, and sets the standby period as the stepping detection period. Make corrections to include. For example, as shown in FIG. 9, when the standby period is equal to or less than the first threshold value TH1 in the sensor signal, the correction unit determines that chattering has occurred, and uses this standby period as the stepping detection period. Make corrections to include. By performing the correction in this way, the sensor signal shown in FIG. 9 becomes a sensor signal as shown in FIG. 10, and signal disturbance such as chattering is eliminated.

In addition, the correction unit determines whether or not the sensor signal is missing, and performs correction to eliminate the missing when the sensor signal is missing.
For example, when the treading detection period that is equal to or smaller than the second threshold TH2 exists and the standby period that is equal to or greater than the third threshold TH3 exists before or after the treading detection period, the correction unit Then, it is determined that a signal loss has occurred in the stepping detection period, and the stepping detection period in which the loss has occurred is lengthened, and the standby period that is equal to or greater than the third threshold TH3 is corrected.

  For example, when the first sensor signal and the second sensor signal as shown in FIG. 11 are input, the correction unit detects the stepping detection period that is equal to or less than the second threshold value TH2, and also performs this stepping. It is determined whether any waiting period before or after the detection period is greater than or equal to the third threshold value TH3. As a result, as shown in FIG. 11, in the second sensor signal, a tread detection period t2B that is equal to or less than the second threshold TH2 is detected. Further, immediately before this tread detection period t2B, the third threshold value is detected. When there is a waiting period t1B that is equal to or greater than TH3, the correction unit determines that the second sensor signal is missing, and uses the first sensor signal that is not missing, Correct the sensor signal.

  Specifically, the correction unit corrects the standby period t2B in the second sensor signal to be a period equivalent to the corresponding standby period t1A in the first sensor signal, and also corrects the second sensor signal in the second sensor signal. The tread detection period t2B is corrected to be longer than the corresponding tread detection period t2A in the first sensor signal.

Here, the “corresponding” means the following.
As shown in FIG. 1, the first tread plate 15a and the second tread plate 15b are stepped on the same tire with a predetermined time difference. Therefore, for example, in the first sensor signal shown in FIG. 11, the first step detection period is a detection that the first step tire is depressed by the tire of the first axis, and the second step detection period t2A. Is detected by being stepped on the tire of the second axis. Similarly, in the second sensor signal shown in FIG. 11, the first step detection period is detected when the first step tire is stepped on, and the second step detection period t2B is: It is detected that the tire has been stepped on the tire of the second axis.

  Thus, the first sensor signal and the second sensor signal are for detecting that the same tire was stepped on, and the stepping detection period in which stepping by the same tire is detected is determined between the sensor signals. Define “corresponding”.

The correction unit replaces the correction process with one cycle including the treading detection period t2B in the second sensor signal and the standby period t1A immediately before the tread detection period t2A, and one corresponding period in the first sensor signal (that is, , One step including the step detection period t2A and the waiting period t1A), and the ratio of the stepping detection period t2B and the waiting period t1B in one cycle of the second sensor signal is the first sensor signal. The second sensor signal may be corrected so as to be substantially equal to the ratio of the tread detection period t2A and the standby period t1A in one corresponding cycle.
In this case, as shown in FIG. 12, the second sensor signal shown in FIG. 11 indicates that the ratio between the tread detection period t2B ′ and the standby period t1B ′ in one cycle corresponds to the first sensor signal. The ratio of the tread detection period t2A and the standby period t1A in one cycle is substantially the same.

  In the above-described example, the case where the second sensor signal is missing has been described. However, when the first sensor signal is missing, based on the second sensor signal, The first sensor signal is corrected by the same method.

  The second threshold value TH2 is set based on, for example, the corresponding stepping detection period t2A (or t2B) in the sensor signal that is not missing. More specifically, a coefficient k2 (a value of 1 or less) determined in accordance with the distance d (see FIG. 2) between the first tread plate 15a and the second tread plate 15b in the tread detection period t2A (or t2B). For example, 0.8).

The third threshold TH3 is set based on, for example, the corresponding stepping detection period t1A (or t1B) in the sensor signal that is not missing. More specifically, a coefficient k1 (1 or less) determined in accordance with the distance d (see FIG. 2) between the first tread plate 15a and the second tread plate 15b in the tread detection period t1A (or t1B). For example, 0.6, etc.).
As described above, the second threshold value TH2 and the third threshold value TH3 are determined for each stepping detection period.

When the omission and chattering in the first sensor signal and the second sensor signal are resolved by performing the correction described above, the tire width determination unit 21 uses the corrected sensor signal to change the tire width of the vehicle 10. Is determined.
For example, the first sensor signal and the second sensor signal determine whether or not the tread detection period overlaps in time. As a result, if they overlap with each other in time, the shaft type is determined as 2, and if there is no time overlap, it is determined as the shaft type 1, and the determination result is output to the vehicle type determination unit 24.

In the above description, the case where the correction process and the tire width determination process are separately performed in the tire width determination unit 21 has been described. However, the tire width determination process and the correction process are performed as one process. It is good also as carrying out collectively.
The processing procedure in this case will be described below with reference to FIG.

First, the tire width determination unit 21 performs chattering correction on the first sensor signal and the second sensor signal (step SA1 in FIG. 13). As shown in FIGS. 9 and 10, the chattering correction is performed so that the standby period is included in the treading detection period when the standby period is equal to or less than the first threshold TH1 set in advance. Is.
When chattering correction is executed in this way, it is detected whether there is an overlapping period of the tread detection period for the corrected first sensor signal and second sensor signal (step SA2). That is, it is determined whether or not there is a period of “H (high)” when the logical sum of the first sensor signal and the second sensor signal is taken. As a result, if there is a temporal overlap in the stepping detection period, it is determined that the shaft type is 2 (step SA3), and the tire width determination process is terminated.

  On the other hand, if there is no overlapping step detection period in step SA2, whether or not the step detection period t2B in the second sensor signal is shorter than the corresponding step detection period t2A in the first sensor signal. Determine (step SA4). As a result, when the stepping detection period t2B in the second sensor signal is shorter than the corresponding stepping detection period t2A in the first sensor signal, the stepping detection period t2B in the second sensor signal is subsequently determined. It is determined whether or not it is smaller than the second threshold value TH2 (= k2 × t2A) (step SA5). Here, the predetermined coefficient k2 is a value determined according to the distance d (see FIG. 2) between the first tread plate 15a and the second tread plate 15b, and is set to a value smaller than 1. .

As a result, when the tread detection period t2B for the second axis in the second sensor signal is equal to or longer than the second threshold TH2 ("NO" in step SA5), it is determined that the vehicle 10 is the shaft type 1. (Step SA6), the tire width discrimination process is terminated.
On the other hand, when the tread detection period t2B for the second axis in the second sensor signal is smaller than the second threshold value TH2 (“YES” in step SA5), the waiting period t1B either before or after the tread detection period t2B. Are smaller than the third threshold TH3 (= k1 × t1A) (step SA7). Here, the predetermined coefficient k1 is a value determined according to the distance d (see FIG. 2) between the first tread plate 15a and the second tread plate 15b, and is set to a value smaller than 1. .
As a result, when the standby period t1B is equal to or greater than the third threshold TH3 (“NO” in step SA7), it is determined that the vehicle 10 is the shaft type 1 (step SA6), and the tire width determination process is performed. finish.

On the other hand, when the standby period t1B is smaller than the third threshold value TH3 (“YES” in step SA7), the standby period t1B in the second sensor signal is substantially equal to the standby period t1A in the first sensor signal. And the second sensor signal is corrected so that the stepping detection period t2B in the second sensor signal is substantially equal to the corresponding stepping detection period t2A in the first sensor signal. (Step SA8).
Subsequently, in the corrected first sensor signal and second sensor signal, it is examined again whether or not there is a temporal overlap in the stepping detection period (step SA12). ("YES" in step SA12) is determined as the shaft type 2 (step SA13), and if there is no overlap ("NO" in step SA12), it is determined as the shaft type 1 and the tire width determination process ends. .

  On the other hand, when the stepping detection period t2B in the second sensor signal is equal to or longer than the corresponding stepping detection period t2A in the first sensor signal (“NO” in step SA4) in step SA4 described above, then Thus, it is determined whether or not the tread detection period t2A in the first sensor signal is shorter than the second threshold TH2 (= k2 × t2B) (step SA9). Here, the predetermined coefficient k2 is a value determined according to the distance d (see FIG. 2) between the first tread plate 15a and the second tread plate 15b, and is set to a value smaller than 1. . The coefficient k2 is the same as the coefficient k2 used in step SA5 described above.

As a result, when the stepping detection period t2A in the first sensor signal is equal to or longer than the second threshold value TH2 ("NO" in step SA9), it is determined that the vehicle 10 is the shaft type 1 (step SA15). Then, the tire width discrimination process is terminated.
On the other hand, when the step detection period t2A in the first sensor signal is smaller than the second threshold TH2 (“YES” in step SA9), the waiting period t1A or the like before or after the step detection period t2A is the third. It is determined whether or not the threshold value TH3 is smaller than (= t1B × k1) (step SA10). Here, the predetermined coefficient k1 is a value determined according to the distance d (see FIG. 2) between the first tread plate 15a and the second tread plate 15b, and is set to a value smaller than 1. . This coefficient k1 is the same as the coefficient k1 used in step SA7 described above.

  As a result, when the standby period t1A is equal to or greater than the third threshold TH3 (“NO” in step SA10), it is determined that the vehicle 10 is the shaft type 1 (step SA15), and the tire width determination process is performed. finish.

On the other hand, when standby period t1A is smaller than third threshold value TH3 (“YES” in step SA10), standby period t1A in the first sensor signal is substantially equal to corresponding standby period t1B in the second sensor signal. And the first sensor signal is corrected so that the stepping detection period t2A in the first sensor signal is substantially equivalent to the corresponding stepping detection period t2B in the second sensor. To do.
Subsequently, in the corrected first sensor signal and second sensor signal, it is examined again whether or not there is a temporal overlap in the stepping detection period (step SA12). ("YES" in step SA12) is determined as the shaft type 2 (step SA13), and if there is no overlap ("NO" in step SA12), it is determined as the shaft type 1 and the tire width determination process ends. .

In the above determination process, the axis type is determined in step SA2 and step SA12 based on whether or not there is an overlap period of the stepping detection period. This overlap period is equal to or greater than the fourth threshold value TH4. It is also possible to determine the axis type depending on whether or not.
For example, as shown in FIG. 14, due to the characteristics of the first tread plate 15a and the second tread plate 15b, sensor signals that are these detected values may have an off-delay. Thus, when an off-delay occurs, the tread detection period becomes longer in the first sensor signal and the second sensor signal. In some cases, an overlap period of the attached detection period occurs. In such a case, it is erroneously determined that the shaft type 1 is the shaft type 2.

  Therefore, in order to eliminate the influence of such an off-delay, when the overlap time of the stepping detection period in the first sensor signal and the second sensor signal is equal to or greater than the fourth threshold value TH4, the axis type 2 It is good also as distinguishing.

Here, the fourth threshold TH4 is set according to the traveling speed of the vehicle. For example, the shorter the traveling speed, the shorter the value is set. The fourth threshold value TH4 is set shorter as the distance d between the first tread plate 15a and the second tread plate 15b is longer.
FIG. 15 shows the relationship between the fourth threshold TH4 and the traveling speed of the vehicle. In FIG. 15, the horizontal axis represents the average speed of the vehicle, and the vertical axis represents the fourth threshold value TH4. As shown in this figure, for example, in a region A where the traveling speed of the vehicle is very slow, such as when there is a traffic jam, the fourth threshold value TH4 is set to a constant value. In the regions B and C where the traveling speed is equal to or higher than the predetermined value, the fourth threshold TH4 is set shorter as the average speed of the vehicle is higher. Further, in the region D in which the running state of the vehicle is very good and no off-delay is considered to occur, the fourth threshold value TH4 is set to zero.

  FIG. 16 shows the relationship between the fourth threshold value TH4 and the vehicle running speed when the distance d between the first tread plate 15a and the second tread plate 15b is wider than in the case of FIG. As shown in FIGS. 15 and 16, it can be seen that the fourth threshold TH4 is set to a smaller value as the distance d increases.

  As described above, in order to eliminate the off-delay of the tire treading detection by the first tread plate 15a and the second tread plate 15b, the tire width determination unit 21 corresponds to, for example, the traveling speed and the fourth threshold value TH4. The attached map is held, and the tire width determination process described above may be executed using the fourth threshold value TH4 corresponding to the travel speed of the vehicle to be determined from the map. As a result, erroneous detection due to off-delay can be eliminated, so that the discrimination accuracy can be improved.

The above-described problem of off-delay similarly occurs in the third tread plate 17a and the fourth tread plate 17b. Therefore, for example, when the vehicle moves forward and backward, depending on the moving speed, as shown in FIG. 17, the tread detection period (period of “H (high)”) in the fourth sensor signal is off. It will be combined by the influence of delay.
In order to cope with such a case, the traveling direction determination unit 23 (see FIG. 4) according to the present embodiment may include a correction unit (correction unit).
For example, in the third sensor signal and the fourth sensor signal, when the step detection period is equal to or greater than the fifth threshold value TH5, the correction unit is coupled to the step detection period due to the off delay. And the following signal correction is performed.
For example, the correction unit divides this step detection period into two and provides a standby period so that each separated step detection period becomes the maximum step detection period Tmax determined according to the traveling speed of the vehicle. . As a result, the stepping detection period in the fourth sensor signal shown in FIG. 17 is separated into two stepping detection periods as shown in FIG. Accordingly, it is possible to determine the traveling direction with higher accuracy using the corrected third and fourth sensor signals.

As described above, according to the vehicle type determination device according to the present embodiment, the tire width determination unit 21 includes a correction unit that corrects the sensor signals detected by the first step board 15a and the second step board 15b. Therefore, for example, when signal disturbance such as chattering or missing occurs in the sensor signals detected by these sensors, it is possible to correct the disturbance of these signals. As a result, the tire width can be determined based on the sensor signal without chattering or omission, and the determination accuracy can be improved.
The vehicle type determination unit 24 performs vehicle type determination using such a highly accurate determination result, thereby improving the accuracy of vehicle type determination.

Furthermore, the traveling direction determination unit 23 also includes a correction unit for eliminating the influence of off-delay and the like, so that the traveling direction can be detected with high accuracy.
In addition, not only the advancing direction discrimination | determination part 23 but the axis | shaft number discrimination | determination part 22 is good also as a structure provided with a correction | amendment part. This makes it possible to determine the number of axes with high accuracy.

  In the above-described embodiment, the first and second step plates 15a and 15b and the third and fourth step plates 17a and 17b detect the stepping of the vehicle by electrical contacts. Instead of this, a sensor that detects the stepping of the vehicle with an optical fiber may be employed. In this case, ON / OFF, that is, stepping on the vehicle is detected based on a change in the light amount of the sensor.

In the above-described embodiment, the control device 20 is premised on processing by hardware, but it is not necessary to be limited to such a configuration. For example, a configuration in which software is separately processed based on output signals from each sensor is also possible. In this case, the control device 20 includes a main storage device such as a CPU and a RAM, and a computer-readable recording medium on which a program for realizing all or part of the above processing is recorded. The CPU reads out the program recorded in the storage medium and executes information processing / arithmetic processing, thereby realizing processing similar to that of the control device 20 described above.
Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the configuration of the above-described vehicle type identification device is an example, and is not limited to this configuration. For example, the overhead sensor 11 may not be provided.
Further, the above-described vehicle type identification device can be applied not only to an automatic fee collection system provided on a toll road, but also to fee collection by a person, for example.

1 is a block diagram illustrating a schematic configuration of a vehicle type identification device according to an embodiment of the present invention. It is a figure for demonstrating the distance d between a 1st tread and a 2nd tread. It is a figure for demonstrating the sensor signal detected by each of a 1st tread and a 2nd tread. It is the block diagram which showed schematic structure of the control apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the discrimination method which discriminate | determines the classification of the tire width by a tire width discrimination | determination part. It is a figure for demonstrating the detection method of the number of axles by the number-of-axis discrimination | determination part. It is a figure for demonstrating the detection method of the advancing direction by a advancing direction discrimination | determination part. It is a flowchart which shows the process sequence of the vehicle type discrimination | determination by a vehicle type discrimination | determination part. It is the figure which showed an example of the sensor signal before correction | amendment by the correction | amendment part of a tire width discrimination | determination part is performed. It is the figure which showed the sensor signal after the sensor signal shown in FIG. 9 was correct | amended by the correction | amendment part of a tire width discrimination | determination part. It is the figure which showed an example of the sensor signal before correction | amendment by the correction | amendment part of a tire width discrimination | determination part is performed. It is the figure which showed the sensor signal after the sensor signal shown in FIG. 11 was correct | amended by the correction | amendment part of a tire width discrimination | determination part. It is the flowchart which showed the process sequence in case correction processing and discrimination | determination processing are collectively performed in a tire width discrimination | determination part. It is a figure for demonstrating an off delay. It is the figure which showed an example of the relationship between 4th threshold value TH4 and the running speed of a vehicle. FIG. 16 is a diagram illustrating an example of a relationship between a fourth threshold value TH4 and the traveling speed of the vehicle when the distance d between the first tread board and the second tread board is increased as compared with the case of FIG. 15. It is the figure which showed the sensor signal when the stepping detection period is combined by the influence of the off delay. It is the figure which showed the sensor signal after the sensor signal shown in FIG. 17 was correct | amended by the correction | amendment part of the advancing direction discrimination | determination part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Overhead sensor 13 Vehicle separator 15a 1st tread 15b 2nd tread 17a 3rd tread 17b 4th tread 20 Control device 21 Tire width discrimination | determination part 22 Axis number discrimination | determination part 23 Travel direction discrimination | determination part 24 Vehicle type discrimination | determination Part

Claims (13)

A first step detection sensor that detects tire depression is disposed on the road surface of the traveling lane obliquely with respect to the traveling direction of the vehicle, and in parallel with the first step detection sensor, A time between a stepping detection period in which a stepping detection sensor is disposed and stepping is detected by the first stepping detection sensor and a stepping detection period in which stepping is detected by the second stepping detection sensor. A tire width discriminating apparatus for discriminating a tire width of a vehicle traveling in the traveling lane based on a degree of overlap,
Correction means for correcting the stepping detection period detected by the first stepping detection sensor and the second stepping detection sensor;
A tire width discriminating apparatus that discriminates a tire width by using a stepping detection period corrected by the correcting means.   The correction means performs the standby when the standby period from the end of detection of one step detection period to the start of detection of the next step detection period is equal to or less than a preset first threshold value. The tire width discriminating apparatus according to claim 1, wherein correction is performed so that the period is included in the stepping detection period.   The correction means is configured such that when one step detection period is equal to or less than a second threshold and a waiting period immediately before or immediately after the one step detection period is equal to or greater than a third threshold, 3. The tire width determination device according to claim 1, wherein correction is performed to increase the one stepping detection period that is equal to or smaller than a threshold value of 2, and to shorten the waiting period that is equal to or greater than a third threshold value.   The correction means detects the stepping detection corresponding to the one stepping detection period detected by the stepping detection sensor that has not detected the one stepping detection period that is equal to or less than the second threshold. The tire width determination device according to claim 3, wherein the correction is performed using a waiting period corresponding to a period and a waiting period that is equal to or greater than the third threshold.   The second threshold value includes the first step detection sensor and the second step detection sensor during the corresponding step detection period detected by the step detection sensor that has not detected the one step detection period. The tire width discriminating device according to claim 3 or 4, wherein the tire width discriminating device is set to a value multiplied by a coefficient determined in accordance with the arrangement relationship of the stepping detection sensor.   The third threshold value includes the first stepping detection sensor and the second stepping amount during the corresponding standby period detected by the stepping detection sensor that has not detected the one stepping detection period. The tire width discriminating device according to any one of claims 3 to 5, wherein the tire width discriminating device is set to a value multiplied by a coefficient determined in accordance with the arrangement relationship of the detection sensors.   The overlap period in which the stepping detection period in which stepping is detected by the first stepping detection sensor and the stepping detection period in which stepping is detected by the second stepping detection sensor overlaps is equal to or greater than the fourth threshold. The tire width discriminating apparatus according to any one of claims 1 to 6, wherein the tire width is discriminated based on whether or not the tire width is.   The tire width determination device according to claim 7, wherein the fourth threshold value is set according to a traveling speed of the vehicle. A third tread detection sensor that detects tire treading is disposed on the road surface of the traveling lane in a direction orthogonal to the traveling direction of the vehicle, and in parallel with the third tread detection sensor. A stepping detection period in which stepping is detected by the third stepping detection sensor, and a stepping detection period in which stepping is detected by the fourth stepping detection sensor. A traveling direction determination device for determining a traveling direction of a vehicle traveling in the traveling lane,
The maximum tread detection period in which when the tread detection period is equal to or greater than the fifth threshold, the tread detection period is divided into two and each separated tread detection period is determined according to the traveling speed of the vehicle So as to include a correction means for providing a waiting period,
A traveling direction determination device that determines the traveling direction of the vehicle using a tread detection period corrected by the correction unit.   A vehicle type discriminating device comprising the tire width discriminating device according to any one of claims 1 to 8, and discriminating a vehicle type. The tire width discrimination device according to any one of claims 1 to 8,
A vehicle type discriminating device that comprises the traveling direction discrimination device according to claim 9 and discriminates the vehicle type of the vehicle. A first step detection sensor that detects tire depression is disposed on the road surface of the traveling lane obliquely with respect to the traveling direction of the vehicle, and in parallel with the first step detection sensor, A time between a stepping detection period in which a stepping detection sensor is disposed and stepping is detected by the first stepping detection sensor and a stepping detection period in which stepping is detected by the second stepping detection sensor. A tire width determination method for determining a tire width of a vehicle traveling in the travel lane based on a typical overlap state,
A tire width determination method of correcting the step detection period detected by the first step detection sensor and the second step detection sensor and determining a tire width using the corrected step detection period. A third tread detection sensor that detects tire treading is disposed on the road surface of the traveling lane in a direction orthogonal to the traveling direction of the vehicle, and in parallel with the third tread detection sensor. A stepping detection period in which stepping is detected by the third stepping detection sensor, and a stepping detection period in which stepping is detected by the fourth stepping detection sensor. A traveling direction determination method for determining a traveling direction of a vehicle traveling in the traveling lane,
The maximum tread detection period in which when the tread detection period is equal to or greater than the fifth threshold, the tread detection period is divided into two and each separated tread detection period is determined according to the traveling speed of the vehicle A traveling direction discriminating method in which a standby period is provided so that the traveling direction of the vehicle is discriminated using each of the stepping detection periods.

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