JP5583067B2 - Vehicle detector - Google Patents

Description

  The present invention relates to a vehicle detector that detects the presence or absence of a vehicle in a predetermined area. More specifically, the present invention includes a transmitter coil and a receiver coil that are spaced apart from each other, and the amount of magnetic flux received on the receiver coil side. It is related with the vehicle detector which detects the presence or absence of a vehicle based on the change of this.

  For example, in a large-scale parking lot facility such as a service area of an expressway, the presence / absence of an empty space is displayed on an electric bulletin board or the like, but when detecting the number of parked vehicles in the parking lot facility, The use of microwaves and the arrangement of loop coils are widely performed.

  As an example, if you set up a pole in the parking space and incorporate a light emitting device or an oscillator such as ultrasonic or microwave in the pole, or in a parking facility with a roof such as an underground parking lot, A light emitting device or an oscillator that emits light, ultrasonic waves, or the like is attached to the parking space.

  In addition, in the case of using a loop coil, a loop coil is embedded in each parking space, and the vehicle is positioned in the parking space, thereby detecting the change in the inductance of the loop coil and detecting the presence or absence of the vehicle. ing.

  However, in the case of the light from the light emitting device, the ultrasonic wave from the oscillator, or the microwave, the monitoring area expands in proportion to the distance, and thus the vehicle in the adjacent parking block may be erroneously detected.

  In addition, since the loop coil is buried in the ground, not only is a great cost burden imposed on the construction, but the magnetic coupling is greatly influenced by the reinforcing bars placed on the concrete floor. Therefore, it is necessary to adjust each burial site. Further, even if a metal body other than the vehicle, such as an empty can, is present on the floor, the magnetic flux may change, and the vehicle may be erroneously detected.

  Therefore, in Patent Document 1, by arranging the inclination angles of the transmission coil and the reception coil to be in a range of 45 ° to 60 ° so as to face each other, the vehicle existing in the detection area is surely disposed. There has been proposed a vehicle detector that detects and prevents malfunction due to a metal object such as an empty can other than the vehicle.

  In this vehicle detector, it is preferable to embed directly under the vehicle stop position in the parking space for detection accuracy. However, as in the case of the embed loop, the burial work cost increases and adjustment after installation is necessary. In addition, there is a problem that maintenance is not easy.

  In order to solve these problems, vehicle sensors with built-in vehicle detectors in the parking block in the parking space are actually commercialized. However, the vehicle blocking block is a hazard that prevents pedestrians from walking and is barrier-free. From the point of view, it is not preferable. In this sense, the parking block type vehicle sensor is not preferred in a large-scale parking lot facility with many pedestrians coming and going.

  Therefore, it was considered to incorporate the above vehicle detector into a car stop pole that does not interfere with pedestrians in the sense that it does not cause a level difference. Another problem arises that the detection sensitivity is reduced due to the distance from the vehicle.

  In the vehicle detector described in Patent Document 1, in order to improve the detection sensitivity, it was also considered to increase the power by changing the coil diameter, the wire, the number of windings, etc. Since the inclination angles of the transmission coil and the reception coil are respectively in the range of 45 ° to 60 °, the wraparound of the magnetic flux from the transmission coil directly toward the reception coil increases, which does not contribute much to the improvement of detection sensitivity.

  In order to reduce the wraparound of the magnetic flux, for example, as is done in the field of metal detectors described in Patent Documents 2 to 4, the transmission coil and the reception coil are made orthogonal to each other. What is necessary is just to arrange | position.

  However, even if this technology is applied to a car stop pole type vehicle detector and the transmitting coil and the receiving coil are accommodated in the car stopping pole so that their respective coil axes are orthogonal to each other, sufficient detection sensitivity is obtained. For example, when a light vehicle is parked in a parking space for a normal car at a position away from the pawl pole, it may not be detected.

  Therefore, at present, in large-scale parking facilities and resting facilities such as service areas (SA) and parking areas (PA) on expressways, a high steel tower is installed and a surveillance camera is installed. The parking situation is monitored.

  However, this has not only a significant introduction cost, but also has the problem that the vehicle in the parking area cannot be detected due to the disturbance of the image due to the influence of weather such as rain, snow or fog, and the shadow of the vehicle with a high vehicle height. There is also a problem that a vehicle hidden behind the vehicle cannot be recognized.

  For this reason, especially in the large-scale parking facilities and rest facilities such as the expressways described above, the vehicle has good detection sensitivity while being inexpensive, can be used for barrier-free, and has good workability and maintainability. A detector is needed.

Japanese Patent No. 2587746 Japanese Patent Laid-Open No. 54-20757 Japanese Patent Application Laid-Open No. 8-105979 JP 2007-298300 A

  Accordingly, an object of the present invention is to provide a magnetic vehicle having a good detection sensitivity and excellent maintainability even when incorporated in a car stop pole standing in a parking space while being simple and inexpensive in construction. It is to provide a detector.

In order to solve the above problems, the present invention provides a primary coil that generates a predetermined magnetic flux and a secondary coil that is disposed at a predetermined interval with respect to the primary coil and detects the magnetic flux of the primary coil. And a detection circuit for outputting a presence / absence signal of the vehicle in the monitoring area of the detection coil by a change in magnetic flux transmitted from the primary side coil to the secondary side coil. In the detector
A car-stop pole made of a non-magnetic material standing in a parking space, the primary coil having a coil axis a substantially vertical in the car-stop pole, and the secondary side as a coil substantially horizontal its coil axis b, which each coil axes of a, b are oriented so as to be substantially perpendicular, and the primary side of the coil axis a, to the center tap of the secondary coil The corresponding coil central part is stored in a state shifted by a predetermined distance.

  In addition, the primary side coil and the secondary side coil may be, for example, a cored coil having a ferrite core or the like, but in order to minimize environmental changes such as temperature, a coreless air-core coil It is preferable that

  According to the present invention, the primary coil and the secondary coil are oriented so that their axes are orthogonal to each other, and the coil of the other coil (preferably the primary coil) is the other coil. By shifting the coil central portion corresponding to the center tap by a predetermined distance, the detection sensitivity of one surface side in the direction opposite to the shifted direction of the other coil can be enhanced.

  In addition, since the polarity of the detection signal is different between the one surface side and the other surface side, the directionality can also be identified. As an application example thereof, if it is installed on the center line between the right traveling road and the left traveling road, it is possible to count the number of passing vehicles on each traveling road with one vehicle detector.

  In addition, since the basic components of the magnetic sensor may be a primary coil and a secondary coil, a detection coil and a detection circuit, the configuration is simple and inexpensive. Furthermore, even if the distance from the vehicle is far, the detection sensitivity is good, and since it is not particularly necessary to embed, the maintenance is excellent.

The block diagram which shows one Embodiment of the vehicle detector of this invention. The schematic diagram which shows an example of the detection coil in this invention. The schematic diagram which shows the inclination angle of the coil accept | permitted in this invention. The typical perspective view which shows the state which installed the said vehicle detector in the parking space as a vehicle stop pole type | mold. The graph which shows the detection characteristic of Example 1 (detection coil by the aspect of FIG. 2a). The graph which shows the detection characteristic of the comparative example 1 (metal detector system).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  As shown in FIG. 1, this vehicle detector is a magnetic sensor based on electromagnetic induction, and is arranged at a predetermined interval in order to detect the vehicle B using a partial area in the parking space A as a monitoring area. Transmission means 1 and reception means 2, and a control means 3 that drives the transmission means 1 and processes a reception signal of the reception means 2.

  The transmission means 1 is composed of a primary side (transmission side) coil 1A that generates magnetic flux, and the reception means 2 is composed of a secondary side (reception side) coil 2A that detects magnetic flux from the primary side coil 1A. A magnetic monitoring area is set by the side coil 1A and the secondary coil 2A.

  In FIG. 1, for convenience of drawing, the primary side coil 1 </ b> A and the secondary side coil 2 </ b> A are arranged coaxially with their respective coil axes as the same axis for convenience of drawing. As shown in FIG. 2a, the primary side coil 1A and the secondary side coil 2A are arranged such that the coil axis a of the primary side coil 1A and the coil axis b of the secondary side coil 2A are orthogonal to each other. The coil central portion corresponding to the center tap of the secondary coil 2A is shifted by a predetermined distance L3 with respect to the coil axis a.

  An oscillator 5 in the control unit 3 is connected to the primary coil 1 </ b> A of the transmission unit 1 via an amplifier (power amplifier) 6. In this embodiment, the oscillator 5 outputs a drive signal for the primary coil 1A at a frequency of several tens of kHz to several tens of kHz in order to avoid the influence of DC magnetism and geomagnetism.

  On the other hand, a reception signal induced by electromagnetic induction in the secondary coil 2A of the reception unit 2 is sent to the mixer 9 via the amplifier 7 and the filter 8 included on the detection circuit side in the control unit 3. The filter 8 is a band filter that attenuates noise components other than the necessary frequency from the received signal.

  In the mixer 9, the received signal is synthesized with the local signal from the local oscillator 10 and frequency-converted. The mixer 9 lowers the frequency of the received signal to several kHz and also functions as a narrow band filter.

  The reception signal attenuated by the mixer 9 is sent to the rectifier 12 via the amplifier 11. The amplifier 11 amplifies the signal (AC signal) attenuated by the mixer 9 to a level that can be converted into a DC signal by the rectifier 12.

  The reception signal converted into direct current by the rectifier 12 is added to the voltage from the reference voltage circuit 14 by the adder 13 at the next stage, and is output from the output terminal 16 to the determination circuit (not shown) via the filter 15. The determination circuit determines the presence or absence of the vehicle by capturing the change in the received signal.

  The reference voltage circuit 14 outputs a predetermined DC voltage to adjust the output of the adder 13 by correcting the influence of the surrounding environment of the installation, for example, unwanted magnetic flux wraparound and the magnetic influence of surrounding metal. The filter 15 is a low-pass filter that attenuates high-frequency component noise of the signal output from the adder 13.

  As shown in FIG. 3, the vehicle detector transmitting means 1 and receiving means 2 are housed in a cylinder 20 of a car stop pole P standing in a parking space A, and used as a car stop pole type sensor.

  The cylindrical body 20 may be formed in a cylindrical shape or a rectangular cylindrical shape made of a nonmagnetic material such as a synthetic resin that allows magnetic flux to pass. The upper end of the cylindrical body 20 is covered with a cap to prevent intrusion of rainwater or the like, but it is preferable to screw it so that it cannot be easily removed due to mischief or the like.

In this embodiment, the primary coil 1A of the transmission means 1 is disposed above and the secondary coil 2A of the reception means 2 is disposed below in the car stop pole P. a, the b are orthogonal to each other, and the coil axis a of the primary coil 1A, the condition that the coil central portion corresponding to the center tap of the secondary coil 2A is shifted by a predetermined distance L3, The secondary coil 2A may be disposed on the upper side and the primary coil 1A may be disposed on the lower side.

  Further, the control means 3 may be stored in a control box (not shown) in a location different from the car stop pole P. If there is an empty space in the car stop pole P, the control means 3 is stored in the empty space. It is preferable.

  When installing the car stop pole P in the parking space A, it is preferable that the coil axis b of the secondary coil 2A is directed to the parked vehicle B side. More preferably, the side opposite to the shifting direction of the secondary coil 2A (R side in FIG. 2a) may be directed to the parked vehicle B side.

  Further, the primary side coil 1A and the secondary side coil 2A may be, for example, a cored coil having a ferrite core or the like. However, since the ferrite core tends to change its characteristics depending on the temperature, for example, a coreless air core. A coil is preferred.

  As an example, when the car stop pole P is installed, the reference voltage circuit 14 is set so that a substantially constant output voltage (reference voltage) appears at the output terminal 16 when the vehicle B is not parked in the parking space A. Adjust it.

  In this state, when the vehicle B is parked in the parking space A, the magnetic flux radiated from the primary side coil 1A is transmitted through the vehicle B and flows more toward the secondary side coil 2A. A voltage corresponding to the amount of magnetic flux is induced as a signal.

  This induced voltage is sent to the mixer 9 via the amplifier 7 and the filter 8, synthesized with a local signal from the local oscillator 10, frequency-converted to remove noise, and then amplified to a predetermined level by the amplifier 11. The rectifier 12 converts the signal into a DC signal, the adder 13 adds the voltage from the reference voltage circuit and 14, and the high frequency component noise is removed by the filter 15, which is then output to the output terminal 16.

  Since the voltage appearing at the output terminal 16 shows a voltage value different from the initially set reference voltage as described above, it can be determined that the vehicle B is parked in the parking space A. In the determination, it is preferable to give a predetermined threshold value to the reference voltage and determine that there is a parked vehicle when the threshold value is exceeded.

  Next, Example 1 in which the detection accuracy of the vehicle detector (car stop pole P) was actually verified and Comparative Example 1 will be described.

  In both Example 1 and Comparative Example 1, the primary side coil 1A and the secondary side coil 2A have an inner diameter of 150 mm, the number of windings is 150 turns (8.5 mH), and the primary side coil 1A and the secondary side coil 2A are separated from each other. The distance L1 was 940 mm, and the distance L2 from the ground to the secondary coil 2A was 187 mm.

  In addition, an 800 × 1250 mm steel plate is used as a metal object instead of an actual vehicle, the center height of the iron plate is 700 mm from the ground, and the iron plate is perpendicular to the ground, and the distance to the car stop pole P is changed. It was.

[Example 1]
As shown in FIG. 2a, the coil axis a of the primary coil 1A is substantially perpendicular to the ground, whereas the coil axis b of the secondary coil 2A is substantially parallel to the ground, and two The central portion corresponding to the center tap of the secondary coil 2A is shifted from the coil axis a of the primary coil 1A by 18 mm as a distance L3 on the left side in FIG.

  Under such conditions, the steel plate in place of the vehicle is gradually brought closer to the stopping pole P from the front side (R direction on the right side in FIG. 2a) and the opposite rear side (left side L in FIG. 2a). The graph of FIG. 4 shows the distance and the amount of change in the reception sensitivity of the secondary coil 2A in the case of gradually approaching the direction).

  In FIG. 4, the square dots are the amount of change on the R side, and the circles are the amount of change on the L side. As can be seen from this graph, the amount of change on the R side is larger than the amount of change on the L side by shifting the center of the secondary side coil 2A from the coil axis a of the primary side coil 1A.

  Considering the detection distance, the iron plate is detected at a distance of about 1.8 m from the iron plate on both the R side and the L side (detection range: about 1.8 m). Since the length of the parking space for ordinary cars is about 3 m, it can be said that the detection capability is sufficient.

  In addition, since the polarity of the change amount on the R side and the change amount on the L side are reversed, the directionality can also be identified by setting a predetermined reference value Vref.

  The coil axis a of the primary side coil 1A and the coil axis b of the secondary side coil 2A are preferably orthogonal to each other. However, as a test example in Example 1, as shown in FIG. When a was tilted by θ °, it was found that good detection accuracy could be obtained if it was in the range of θ ° = ± 2.3 °. The shift distance L3 is preferably within a range of ± 22 mm (22 mm for both the R side and the L side).

[Comparative Example 1]
The shift distance L3 of the secondary side coil 2A is set to L3 = 0, and the primary side coil 1A and the secondary side coil 2A are set so that their coil axis lines a and b are orthogonal to each other in the same manner as the metal detector. Except for the arrangement, the reception sensitivity of the secondary coil 2A was observed as in the first embodiment. The amount of change is shown in the graph of FIG.

  In FIG. 5, square dots are the amount of change on the R side, and ◯ is the amount of change on the L side. In the case of Comparative Example 1, both the amounts of change on the R side and L side are the amounts of change on the R side in Example 1. Further, the iron plate is detected at a distance of about 1.2 m from the iron plate (detection range: about 1.2 m). With this detection capability, for example, when a light vehicle is parked near the entrance of a parking space for ordinary vehicles, it may not be detected. Further, the R side and the L side have the same polarity, and the directionality cannot be identified.

  In the above embodiment, the coil axis a of the primary coil 1A is substantially vertical, and the coil axis b of the secondary coil 2A is substantially horizontal. On the contrary, the coil axis a of the primary coil 1A is substantially horizontal, The coil axis b of the secondary coil 2A may be substantially vertical.

  Moreover, the arrangement | positioning in the pole P for a vehicle stop can be replaced | exchanged, and the primary side coil 1A can also be arrange | positioned to the lower side and the secondary side coil 2A can be arrange | positioned to the upper side. Each of the coils 1A and 2A may be cylindrical or rectangular.

  Further, as described above, the vehicle detector is preferably housed in the car stop pole P. However, depending on the case, the vehicle detector may be incorporated in the car stop block or may be embedded in the ground. .

DESCRIPTION OF SYMBOLS 1 Transmission means 1A Primary side coil 2 Reception means 2A Secondary side coil 5 Oscillator 6, 7, 11 Amplifier 8, 15 Filter 9 Mixer 10 Local oscillator 12 Rectifier 13 Adder 14 Reference voltage circuit 16 Output terminal 20 Tubular body a Primary side Coil axis of coil b Coil axis of secondary coil A Parking space B Vehicle P Car stop pole

Claims (2)

A primary coil that generates a predetermined magnetic flux and a detection coil that is disposed at a predetermined interval with respect to the primary coil and that includes a secondary coil that detects the magnetic flux of the primary coil; and the primary coil In a vehicle detector comprising a detection circuit that outputs a presence / absence signal of a vehicle in a monitoring area of the detection coil by a change in magnetic flux transmitted to the secondary side coil,
A car-stop pole made of a non-magnetic material standing in a parking space, the primary coil having a coil axis a substantially vertical in the car-stop pole, and the secondary side as a coil substantially horizontal its coil axis b, which each coil axes of a, b are oriented so as to be substantially perpendicular, and the primary side of the coil axis a, to the center tap of the secondary coil A vehicle detector characterized in that the corresponding coil central portion is housed in a state shifted by a predetermined distance. The vehicle detector according to claim 1, wherein the primary side coil and the secondary side coil are coreless air-core coils.

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