JPS62135789A - Vehicle detecting device - Google Patents

Abstract

PURPOSE:To obtain the detecting device of a small size and also a low cost, which can be attached easily, by placing a magnetic sensor formed by winding round a pair of output windings so as to be orthogonal to each other, to 'Permalloy(R)' to which an exciting winding is wound in the direction of a prescribed vehicle detecting position. CONSTITUTION:The magnetic sensor 20 is formed by winding an exciting winding 24 to a 'Permalloy(R)' ring 22 being a ferromagnetic material, and also winding round a pair of X axis output winding 26X and Y axis output winding 26Y so as to be orthogonal electrically to each other. To the exciting winding 24, a prescribed AC voltage is applied from an excitation driving circuit 28, and an alternating magnetic field is generated in the 'Permalloy(R)' ring 22. When this magnetic sensor 20 is placed in the direction of a prescribed vehicle detecting position, when a vehicle does not exist in the vehicle detecting position, the earth magnetism of about 300m gauss is detected. Also, when a vehicle exists in the vehicle detecting position, the magnetic field of about 1-2 gauss which has synthesized the earth magnetism and a vehicle magnetism is detected usually. In this way, based on the strength of the magnetism detected by the magnetic sensor 20, the vehicle in a vehicle detecting position can be detected exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle detection device, and more particularly to a device for detecting the presence or absence of a vehicle based on changes in magnetic field strength.

[Prior Art] Today, vehicle detection devices are widely used in various fields. For example, they are used in vehicle entrance/exit gates to automatically control the opening and closing of the gates, and in parking lots, etc. It is used to understand the parking status of vehicles in parking spaces in real time and to make efficient use of parking spaces.

Loop coil type devices and ultrasonic type devices are conventionally known as vehicle detection devices, and these detection devices are widely used because they can reliably detect the presence or absence of a vehicle without contact. It is commonly used.

FIG. 5 shows a loop coil type vehicle detection device installed at a vehicle entrance/exit gate. This detection device has a vehicle detection loop coil 10 embedded in the road surface, and the output of this loop coil 10 is The judgment circuit is powered by 12 people.

The determination circuit 12 detects the presence or absence of a vehicle based on the change in the output of the loop coil 10, and controls the opening and closing of the gate.

Further, FIG. 6 shows an ultrasonic vehicle detection device installed at the entrance/exit gate of a vehicle, and this device transmits an ultrasonic beam from an ultrasonic transducer 14 toward a detection position of the vehicle. It is transmitting and receiving waves. Then, the determination circuit 12 detects the presence or absence of a vehicle based on the time from transmission to reception of such an ultrasonic beam, and controls the opening and closing of the entrance/exit gate.

[Problems to be Solved by the Invention] However, such conventional vehicle detection devices often have the problem that the work required to install the loop coil 10 and the ultrasonic transducer 14 is difficult.

In particular, with loop coil type devices, it is necessary to bury the loop coil 10 in the road surface, so if such a device is to be installed after the fact, it is necessary to dig the ground again to bury the loop coil. As a result, the installation of the device becomes more expensive, and the installation process becomes cumbersome and complicated.

Another problem with these conventional devices is that the overall size of the device is small, making it difficult to easily install it in a limited space, and the cost per unit is extremely high. was there.

OBJECTS OF THE INVENTION The present invention has been made in view of such conventional problems, and its purpose is to provide a vehicle detection device that can be easily installed, is small in size, and is low in cost.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a magnetic sensor in which a pair of output windings are wound orthogonally to each other around a permalloy around which an excitation winding is wound. It is placed facing a predetermined vehicle detection position.

By doing this, the magnetic sensor detects geomagnetic G of about 300 m Gauss when there is no vehicle at the vehicle detection position. will be detected, and if there is a vehicle at the vehicle detection position, the earth's magnetic field? : Magnetic field α2) whose strength is the combination of both the magnetic fields of Ao and the vehicle magnetic field α2) Usually 1 to 2
A magnetic field as strong as a gas wave is detected.

Therefore, according to the present invention, the presence or absence of a vehicle at the vehicle detection position can be reliably detected based on the strength of the magnetic field detected by the magnetic sensor.

[Function] As described above, according to the present invention, by moving a magnetic sensor formed by winding an excitation winding and a pair of output windings around permalloy to a predetermined vehicle detection position, Since the presence or absence of a vehicle can be detected, the entire device can be made smaller and less expensive than conventional devices using loop coils or devices using ultrasonic transducers.

Moreover, according to the present invention, since the sensor itself is small and its installation is extremely simple, it is possible to install a vehicle detection device after the fact, for example, at an already completed entrance/exit gate or parking lot. Also, the installation of the device itself, especially the sensor portion, can be done much more easily than in conventional devices.

[Example] Next, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a preferred embodiment of a magnetic sensor 20 used in the vehicle detection device of the present invention. The wire 24 is wound, and a pair of X-axis output windings 26 are further wound.
The X- and Y-axis output windings 26Y are wound electrically orthogonally to each other.

A predetermined alternating current voltage is applied to the excitation winding 24 from an excitation drive circuit 28 to generate an alternating magnetic field within the permalloy ring 22.

By doing so, the output windings 26X, 26Y of the magnetic sensor 20 output voltages X, y according to the interlinking magnetic fluxes.

A characteristic feature of the present invention is that the magnetic sensor 20 formed in this manner is placed facing a predetermined vehicle detection position, and the presence or absence of a vehicle is detected based on the strength of the detected magnetic field i (x, y). The purpose is to detect.

In the present invention, the magnetic sensor 20 can be made extremely compact, and the sensor 20 of the embodiment has a permalloy ring 22 with a diameter of about 6 mm, making it extremely inexpensive.

Moreover, according to the present invention, there is no need to specifically bury the magnetic sensor 20 formed in this way in the road surface, and it is sufficient to simply place it facing the vehicle detection position, which simplifies the installation of the device. In particular, when installing the vehicle detection device after the fact, the installation work is extremely simple compared to the labor involved.

FIG. 2 shows detection characteristics when the magnetic sensor 20 of this embodiment is placed at a predetermined vehicle detection position.

As is clear from the figure, when there is no vehicle at the vehicle detection position (empty vehicle state), the magnetic sensor 20 detects approximately 30
Earth's magnetic field G of about 0 tome force. Detect.

On the other hand, when a vehicle is parked at the vehicle detection position, the magnetic sensor 20 detects the earth's magnetic field Go and the vehicle's magnetic field G.
A magnetic field G2 synthesized with G1 is output. This composite magnetic field spans,
When the vehicle is close to the magnetic sensor 20, the intensity is about 1 to 2 caus, which is the geomagnetic field α. It is several times larger than the

From this, it is understood that according to the present invention, it is possible to accurately detect the presence or absence of a vehicle at a predetermined vehicle detection position based on the magnetic field strength detected by the magnetic sensor 20.

FIG. 3 shows a specific configuration of a vehicle detection device formed using the magnetic sensor 20, and the device of the embodiment has the following features:
．． The presence or absence of a vehicle in ... is detected separately and independently.

For this reason, each parking space 100-1.100-2.・
・Multiple magnetic sensors 20-1゜20-2・
... is provided, and each magnetic sensor 20-1.20-
The detection outputs of 2... are input to the arithmetic circuit 30.

This arithmetic circuit 30 operates on each of the magnetic sensors 20-1 and 20-2.
Based on the detection signal α(x,y) output from the output windings 26X, 26Y of...
100-2. Detecting the presence or absence of a vehicle in...

FIG. 4 shows a preferred embodiment of such an arithmetic circuit 30. a memory 32 in which the value of is recorded, and each of the magnetic sensors 20
-1.20-2... and a plurality of sets of calculation units 34-1.34-2... and comparison units 36-1.3 provided in correspondence with each other.
6-2... is included.

Here, in the memory 32, the value of earth's magnetic field ■0 is decomposed into components in the X direction (east-west direction) and the Y direction (north-south), and stored as Q□-(x□, y□). ing.

Further, each calculation unit 34-1, 34-2 stores the detection signal '1-(x, y) outputted from the corresponding magnetic sensor 20-1, 20-2... and the memory 36. Using the written and stored geomagnetism '1O-(X□, yo), ΔC is Δi=+6-G based on the following formula. 1. The comparators 36-1, 36-2, . It is determined whether or not the large serration of the output Δ stone is 0.5 Gauss or more. If Δα is 0.5 Gauss or more, it is determined that the vehicle is in a parked state and a signal of 1 level is outputted, and if it is less than that, it is determined that the vehicle is in an empty state and an L level signal is output.

In this way, according to the device of this embodiment, the presence or absence of a vehicle in each parking space 100-1, 100-2°, etc. of the parking lot can be accurately detected, and the parking lot can be efficiently used. It becomes possible to plan the operation.

In the above embodiments, the case where 0.5 galax was set as the reference value was explained as an example, but the present invention is not limited to this, and the present invention is not limited to this. be able to.

In the above embodiments, the case where the device of the present invention is used in a parking lot was explained as an example, but the present invention is not limited to this, but can also be applied to heavy vehicle detection at vehicle entrance/exit gates and other locations. It is also possible to use

[Effects of the Invention] As explained above, according to the present invention, the entire vehicle detection device can be made small and inexpensive, and its installation can be easily carried out. .

In particular, according to the present invention, even when the vehicle detection device is installed afterwards, the installation can be done extremely easily compared to conventional devices.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a preferred embodiment of the magnetic sensor used in the vehicle detection device according to the present invention, FIG. 2 is a characteristic diagram of the magnetic sensor shown in FIG. 1, and FIG. 3 is a diagram showing the characteristics of the magnetic sensor shown in FIG. 4 is a specific explanatory diagram of a vehicle detection device formed using the magnetic sensor shown in FIG.
6 and 6 are explanatory diagrams of a conventional vehicle detection device. 20... Magnetic sensor 22... Permalloy ring 24... Excitation winding 26X, 26Y... Output winding 30... Arithmetic circuit 32... Memory 34... Arithmetic unit 36... Comparison Department

Claims (2)

[Claims] (1) A magnetic sensor including a permalloy around which an excitation winding is wound and a pair of output windings wound around the permalloy so as to be perpendicular to each other is arranged toward a predetermined vehicle detection position, A vehicle detection device that detects the presence or absence of a vehicle at a vehicle detection position based on a magnetic field detected by a magnetic sensor. (2) In the device according to claim (1), the number 1
A value of about 00 m Gauss is set as a reference value, and the presence or absence of a vehicle at a vehicle detection position is detected based on whether a value obtained by subtracting geomagnetism from the output of the magnetic sensor exceeds the reference value. Vehicle detection device.