JPH1137707A - Device for detecting position of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of magnetic detectors used for detecting the position of a vehicle and, at the same time, to detect the position of the vehicle with a simple constitution. SOLUTION: A pair of magnetic detectors 12 are respectively attached to the left and right sides of a vehicle and, at the same time, a control unit 15, which computes the difference between the detect signals a1 and a2 outputted from the detectors 12 is provided. The control unit 15 outputs a pulse signal (b) the amplitude of which varies depending upon the difference between the detect signals al and a2. The rotation of the steering 17 of the vehicle is controlled by means of a motor 16 so that the vehicle may travel in the middle of a traveling lane by driving the motor 16 based on the pulse signal (b) outputted from the unit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle position detecting device for detecting the position of a vehicle for guiding a vehicle traveling on the road surface. The present invention relates to a vehicle position detecting device that detects a position of a vehicle by detecting a generated magnetic flux.

[0002]

2. Description of the Related Art Conventionally, in order to assist driving and automatic driving of a vehicle, a vehicle position detecting device for detecting a position of a vehicle by detecting a magnetic flux generated from the magnet by burying a magnet on a traveling road surface. Is described in, for example, Japanese Patent Application Laid-Open No. 8-20100.
No. 6 is known.

Here, a vehicle position detecting device according to the prior art will be described with reference to FIGS. As shown in FIG. 5, a traveling lane 1A on which the vehicle should travel
Are formed. A plurality of magnets 2, 2,... Are embedded in the traveling road surface 1. Each magnet 2 is located at the center of the traveling lane 1A and is arranged at, for example, 1 m intervals in the traveling direction.

On the other hand, as shown in FIG. 6, the vehicle 3 is provided with five magnetic detectors 4, 4,... For detecting magnetic fluxes generated from the respective magnets 2 buried in the running road surface 1. . Each magnetic detector 4 is one at the center in the left-right direction of the vehicle, and
Two are provided on the left and right sides at equal intervals. Each magnetic detector 4 is connected to a signal processing circuit (not shown) mounted on the vehicle 3. Each magnetic detector 4 has a voltage value corresponding to a magnetic flux generated from each magnet 2. Is output to the signal processing circuit.

When the vehicle 3 travels on the road surface 1, the magnetic flux of each magnet 2 embedded in the road surface 1 is constantly detected by each magnetic detector 4. For example, when the vehicle 3 is traveling in the center of the traveling lane 1A on the traveling road surface 1, the magnetic detector 4 provided at the center in the left-right direction of the vehicle 3 is opposed to each magnet 2 in the up-down direction. . As a result, the magnetic flux detected by the central magnetic detector 4 becomes the largest among the magnetic detectors 4, and the voltage value of the analog signal output from the magnetic detector 4 becomes
Is the largest among the analog signals output from.

On the other hand, when the vehicle is traveling with the vehicle leaning to the left side of the traveling lane 1A, the magnetic flux detected by the magnetic detector 4 provided on the right side of the vehicle 3 is the largest among the magnetic detectors 4. The voltage value of the analog signal output from the magnetic detector 4 becomes the maximum among the analog signals output from the magnetic detectors 4.

As described above, by detecting which of the magnetic detectors 4 has the largest voltage value among the analog signal voltages output from the respective magnetic detectors 4, the current traveling state is detected. The position of the middle vehicle 3 in the left-right direction can be recognized, and based on this, the traveling direction of the vehicle 3 can be controlled so that the vehicle 3 travels in the center of the traveling lane 1A.

[0008]

In the above-mentioned prior art, the vehicle 3 is provided with five magnetic detectors 4, and the position of the vehicle 3 is recognized based on the magnetic flux detected from each magnetic detector 4. Configuration.

However, since the five magnetic detectors 4 are provided in the vehicle 3, there is a problem that not only the device becomes complicated and large, but also the manufacturing cost increases.

Further, in the above-mentioned prior art, since the voltage value of the analog signal output from the five magnetic detectors 4 is the largest, the analog signal output from each magnetic detector 4 is detected. It is necessary to compare the voltage values of the signals with high accuracy. As a result, the accuracy of each magnetic detector 4 must be increased, and there is a problem that the manufacturing cost is further increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been made in consideration of the above-described problems. It is intended to provide a detection device.

[0012]

According to a first aspect of the present invention, a magnetic flux generated from a plurality of magnets located at the center of a traveling road surface and arranged at equal intervals in a traveling direction. In a vehicle position detection device that detects the position of the vehicle in the left-right direction by detecting the left and right sides of the vehicle, a pair is provided symmetrically on the left and right sides of the vehicle, and outputs a detection signal corresponding to a magnetic flux generated from each of the magnets. And a signal comparing unit that compares the detection signals output from the respective magnetic detectors with each other and outputs a digital signal whose state changes according to the comparison result. is there.

With this configuration, when the vehicle is traveling on the left side of the traveling road surface, the magnetic detector provided on the right side of the vehicle approaches each magnet provided on the traveling road surface. At the same time, the magnetic detector provided on the left side of the vehicle moves away from each magnet. As a result, the magnetic flux detected by the magnetic detector provided on the right side of the vehicle becomes larger than the magnetic flux detected by the magnetic detector provided on the left side of the vehicle. (For example, voltage) of the detection signal output from the detector
Is higher than the level of the detection signal from the magnetic detector provided on the left side of the vehicle.

On the other hand, when the vehicle is traveling on the right side of the running road surface, the magnetic detector provided on the left side of the vehicle approaches each magnet provided on the running road surface, The provided magnetic detector moves away from each magnet. As a result, the magnetic flux detected by the magnetic detector provided on the left side of the vehicle becomes larger than the magnetic flux detected by the magnetic detector provided on the right side of the vehicle. The level of the detection signal output from the detector becomes higher than the level of the detection signal from the magnetic detector provided on the right side of the vehicle.

As described above, the magnitude relationship between the detection signals output from the respective magnetic detectors depends on whether the vehicle is traveling on the left side or on the right side of the traveling road surface. Change.

The signal comparing means compares the detection signal output from the magnetic detector provided on the left side of the vehicle with the detection signal output from the magnetic detector provided on the right side of the vehicle. Digital signal whose state changes according to the comparison result, for example, amplitude, frequency,
A digital signal whose duty ratio or the like changes is output.

Thus, it is possible to easily determine whether the vehicle is running leftward or rightward based on the digital signal output from the signal comparing means. Can be.

According to a second aspect of the present invention, the signal comparing means includes:
When the detection signal output from the magnetic detector provided on the right side of the vehicle is larger than the detection signal output from the magnetic detector provided on the left side of the vehicle, a pulse signal having a first amplitude level is output. Has a second amplitude level different from the first amplitude level when the detection signal output from the magnetic detector provided on the left side of the vehicle is larger than the detection signal output from the magnetic detector provided on the right side of the vehicle The configuration is such that a pulse signal is output.

With this configuration, when the vehicle is traveling on the left side of the traveling road surface, the detection signal output from the magnetic detector provided on the right side of the vehicle is provided on the left side of the vehicle. The signal comparison means outputs a pulse signal having the first amplitude level because the detection signal becomes larger than the detection signal output from the magnetic detector. On the other hand, when the vehicle is traveling on the right side of the road surface, the detection signal output from the magnetic detector provided on the left side of the vehicle is output from the magnetic detector provided on the right side of the vehicle. Since it is larger than the detection signal, the signal comparison means
A pulse signal having a second amplitude level is output.

By determining whether the amplitude level of the pulse signal output from the signal comparing means is the first amplitude level or the second amplitude level, the vehicle can be shifted to the left with respect to the center of the traveling road surface. It is possible to easily determine whether the vehicle is in a state of leaning toward the right side.

According to a third aspect of the present invention, the signal comparing means includes:
The configuration is such that the respective detection signals are compared with each other by calculating the difference between the detection signals output from the respective magnetic detectors.

With this configuration, the magnitude of each detection signal can be determined by determining whether the difference between the detection signals output from the respective magnetic detectors is positive or negative. Can be compared.

According to a fourth aspect of the present invention, each of the magnetic detectors comprises:
It is provided on a vehicle so as to face a traveling road surface and to detect a vertical magnetic flux generated from each magnet.

With this configuration, each magnetic detector is provided so as to face the traveling road surface.
A magnetic flux other than the vertical direction generated from the magnet, such as a magnetic flux in the horizontal direction, is excluded, and only the magnetic flux in the vertical direction generated from the magnet can be detected.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 4 show a vehicle position detecting device according to an embodiment of the present invention. In the present embodiment, the same reference numerals are given to the same components as those of the above-described conventional technology, and the description thereof will be omitted.

Reference numeral 11 denotes a vehicle position detecting device installed in the vehicle 3 according to the present embodiment. The vehicle position detecting device 11 includes a plurality of magnets located at the center of the traveling road surface 1 and arranged at regular intervals in the traveling direction. By detecting the magnetic flux generated from 2,
The position of the vehicle 3 in the left-right direction is detected.

Numerals 12 and 12 denote a pair of magnetic detectors for outputting detection signals a1 and a2 corresponding to the magnetic flux generated from the magnet 2. Each of the magnetic detectors 12 is, as shown in FIG.
Are provided symmetrically on the left side and the right side, respectively.

More specifically, each magnetic detector 12 is constituted by a Hall element.
Converts a magnetic flux generated from the magnet 2 into an electric signal, and detects a detection signal a having a voltage corresponding to the magnetic flux generated from the magnet 2.
1 and a2 are output. The detection signals a1 and a2 output from the respective magnetic detectors 12 are amplified by amplifiers 13 and 13 provided near the respective magnetic detectors, and input to the arithmetic unit 15 described later.

Each magnetic detector 12 and each amplifier 13
Are arranged on the front side of the vehicle 3, for example, in the vicinity of the front bumper, by the mounting members 14, 14, respectively. Here, as shown in FIG. 2, each of the magnetic detectors 12 is mounted on the lower surface of the mounting member 14, and is arranged downward so as to face the traveling road surface 1. Thereby, each magnetic detector 1
2 detects only the magnetic flux in the direction perpendicular to the traveling road surface 1 among the magnetic fluxes generated from the magnet 2, as indicated by an arrow A in FIG.

The left and right magnetic detectors 12 are magnets 2
Signal a of the same voltage corresponding to the magnetic flux generated from
1 and a2 are adjusted with each other. Further, the respective amplification factors of the left and right amplifiers 13 are basically set to be the same, but when there is a slight variation in the output of each magnetic detector 12, the gain is adjusted so as to eliminate the variation.

Reference numeral 15 denotes a signal comparing means for calculating a difference between the detection signals a1 and a2 output from the respective magnetic detectors 12 and outputting an output pulse signal b whose amplitude level changes according to the calculation result. The arithmetic unit 15 includes, for example, a microcomputer, a multi-processing unit, and the like, and is provided in the vehicle 3. Each magnetic detector 12 is connected to the input side of the arithmetic unit 15 via each amplifier circuit 13, and the detection signals a1 and a2 output from each magnetic detector 12 are input. Further, the output side of the arithmetic unit 15 is connected to a control unit 16 described later.

In the arithmetic unit 15, an analog-digital conversion circuit 15A (hereinafter, referred to as an analog-to-digital converter) for converting analog detection signals a1 and a2 output from each magnetic detector 12 and input to the arithmetic unit 15 into digital signals. "A /
D conversion circuit 15A ") and the A / D conversion circuit 15A.
There is provided a digital difference circuit 15B for calculating the difference between the two detection signals a1 and a2 digitized by the above.

Here, the digital difference circuit 15B calculates the difference between the two detection signals a1 and a2 output from each magnetic detector 12 and digitized by the A / D conversion circuit 15A. An output pulse signal b as shown in FIG. 4 is output. That is, as a result of calculating the difference between the respective detection signals a1 and a2, the detection signal a1 output from the magnetic detector 12 provided on the right side of the vehicle 3 is output from the magnetic detector 12 provided on the left side of the vehicle 3. When it is larger than the detection signal a2 (for example, when the difference value is positive), the output pulse signal b at a high level (first amplitude level) is output.
On the other hand, as a result of calculating the difference between the respective detection signals a1 and a2, the detection signal a2 output from the magnetic detector 12 provided on the left side of the vehicle 3 becomes the magnetic detector 1 provided on the right side of the vehicle 3.
When the detection signal a1 is larger than the detection signal a1 (for example, when the difference value is negative), the output pulse signal b of a low level (second amplitude level) is output.

Numeral 16 denotes a control unit for steering control for automatically turning the steering wheel 18. Inside the control unit 16, an arithmetic unit 1 is provided.
5 is provided with an arithmetic circuit 16A that receives the output pulse signal b output from the digital difference circuit 15B and calculates a steering angle serving as a steering control amount based on the output pulse signal b. Then, the arithmetic circuit 16A outputs a drive signal to the electric motor 17 based on the output pulse signal b,
The steering device 18 is operated.

That is, the control unit 16 determines whether the output pulse signal b is at a high level or a low level. When the output pulse signal b is at a high level, the steering device 18 is turned rightward by a small steering angle (for example, 1 degree). A drive signal is output to operate. On the other hand, when the output pulse signal b is at a low level, a drive signal is output so as to operate the steering device 18 to the left by a small steering angle (for example, 1 degree).

Here, the steering angle at which the steering device 18 is operated by the electric motor 17 may be changed in accordance with the vehicle speed of the vehicle 3. For example, if the vehicle speed is 1
At 00 km, the steering angle is set to 1 degree and the vehicle speed is 80 km
In this case, the steering angle is set to 1.5 degrees. As described above, by increasing the steering angle in accordance with the decrease in the vehicle speed, the position of the vehicle in the left-right direction can be accurately and quickly controlled.

The vehicle position detecting device according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

When the vehicle 3 starts traveling on the traveling road surface 1, each of the magnetic detectors 12 detects a vertical magnetic flux among the magnetic fluxes generated from the magnet 2, and detects detection signals a1, a2.
Is output to the arithmetic unit 15.

Here, for example, when the vehicle 3 is traveling in a state shifted to the left side of the traveling lane 1A set on the traveling road surface 1, the magnetic detector 12 provided on the right side of the vehicle 3 is driven by the magnetic detector 12. While approaching each magnet 2 provided in the center of 1, the magnetic detector 12 provided on the left side of the vehicle 3 moves away from each magnet 2. Thereby, the magnetic flux detected by the magnetic detector 12 provided on the right side of the vehicle 3 becomes larger than the magnetic flux detected by the magnetic detector 12 provided on the left side of the vehicle 3, A detection signal a1 output from the magnetic detector 12 provided is a detection signal a from the magnetic detector 12 provided on the left side of the vehicle 3.
It is larger than 2.

On the other hand, when the vehicle 3 is traveling in a state shifted to the right side of the traveling lane 1A, the detection signal a2 output from the magnetic detector 12 provided on the left side of the vehicle 3 becomes:
It is larger than the detection signal a1 from the magnetic detector 12 provided on the right side of the vehicle 3. As described above, each magnetic detector 1 depends on whether the vehicle 3 is traveling on the left side of the traveling lane 1A or traveling on the right side.
2 changes the magnitude relationship between the detection signals a1 and a2.

The detection signals a1 and a2 output from the magnetic detectors 12 are amplified by the amplifiers 13 and then input to the arithmetic unit 15. Each of the detection signals a1 and a2 is converted into a digital signal by the A / D conversion circuit 15A, and is input to the digital difference circuit 15B. Further, the digital difference circuit 15B calculates a difference between the two digitized detection signals a1 and a2, and outputs an output pulse signal b based on the calculation result.

That is, when the detection signal a1 output from the magnetic detector 12 provided on the right side of the vehicle 3 is larger than the detection signal a2 from the magnetic detector 12 provided on the left side of the vehicle, each detection signal The difference value between a1 and a2 is, for example, positive (a1-a2> 0). At this time, the digital difference circuit 1
5B outputs the output pulse signal b having the high amplitude level to the control unit 16. On the other hand, the detection signal a2 output from the magnetic detector 12 provided on the left side of the vehicle 3 is the same as the detection signal a2 provided on the right side of the vehicle.
When each detection signal a1 is larger than the detection signal a1 from the
The difference value between 1 and a2 is, for example, negative (a1-a2 <0).
At this time, the digital difference circuit 15B outputs the output pulse signal b having the low level to the control unit 1.
6. Output to 6.

Then, the control unit 16 having received the output pulse signal b drives the electric motor 17 based on the amplitude level of the output pulse signal b to operate the steering device 18 by a small steering angle. That is, when receiving the high-level output pulse signal b, the control unit 16 operates the steering device 18 by a small steering angle to the right. As a result, the vehicle 3 traveling in a state shifted to the left side of the traveling lane 1A is automatically controlled so that its traveling direction is slightly rightward. On the other hand, when receiving the low-level output pulse signal b, the control unit 16 drives the steering device 18 to slightly operate the steering device 18 to the left. As a result, the vehicle 3 traveling in a state shifted to the right side of the traveling lane 1A
Is automatically controlled so that its traveling direction is slightly leftward.

As described above, when the vehicle 3 approaches the left side of the traveling lane 1A, the traveling direction of the vehicle 3 is corrected to be slightly rightward, and when the vehicle 3 approaches the right side of the traveling lane 1A, The traveling direction of the vehicle 3 is corrected so as to be slightly leftward. By repeating such control at all times, the vehicle 3 travels in the center of the traveling lane 1A so as to be guided by each magnet 2.

Thus, according to the present embodiment, the traveling road surface 1
Are provided on the left and right sides of the vehicle 3, respectively, and a detection signal a output from each of the magnetic detectors 12 is provided on the left and right sides of the vehicle 3.
By calculating the difference between the detection signals a1, a2,
Since the output pulse signal b whose amplitude level changes in two stages is output based on the result of the operation, it is determined whether the amplitude level of the output pulse signal b is high or low. Only by this, it is possible to easily determine whether the vehicle 3 is shifted to the left or to the right with respect to the center of the traveling lane 1A. Therefore, based on the output pulse signal b, it is possible to easily control the vehicle 3 to travel in the center of the traveling lane 1A.

The difference between the detection signal a1 from the magnetic detector 12 provided on the right side of the vehicle 3 and the detection signal a2 from the magnetic detector 12 provided on the left side of the vehicle 3 is calculated. Therefore, the detection signals a1, a output from the respective magnetic detectors 12 due to temperature changes and mixing of external noise.
Even if errors similar to each other occur in each of 2, such errors can be removed and the detection sensitivity can be increased. That is, even if the same error occurs in the detection signal a1 of the right magnetic detector 12 and the detection signal a2 of the left magnetic detector 12 due to the influence of the change of the ambient temperature or the like, the detection signals of the respective magnetic detectors 12 may be different. By calculating the difference between a1 and a2, errors generated in the respective detection signals a1 and a2 can be canceled and removed.

Further, the vehicle position detecting device 11 of the present embodiment
Can realize vehicle position detection by two magnetic detectors 12. Also, only by comparing the magnitudes of the detection signals a1 and a2 output from the two magnetic detectors 12,
The displacement of the vehicle 3 with respect to the center of the traveling lane 1A can be detected. Therefore, the number of magnetic detectors can be reduced as compared with the related art, and the device can be reduced in size, the configuration can be simplified, and the manufacturing cost can be reduced.

Further, according to the present embodiment, whether the vehicle 3 is shifted to the left or right with respect to the center of the traveling lane 1A is output from the arithmetic unit 15. Since the configuration is such that the output pulse signal b is output by switching the amplitude (high level / low level), the displacement of the vehicle can be easily determined. Therefore,
Driving the electric motor 17 based on the output pulse signal b,
By operating the steering device 18 leftward or rightward, the traveling direction of the vehicle 3 can be easily controlled so that the vehicle 3 travels in the center of the traveling lane 1A.

In the above embodiment, each magnetic detector 12
Is constituted by a Hall element as an example, but the present invention is not limited to this, and each magnetic detector 12 may be a magnetoresistive element,
You may comprise by a pickup coil etc.

In the above-described embodiment, the arithmetic unit 15 having the A / D conversion circuit 15A and the digital difference circuit 15B has been described as an example of the signal comparison means. However, the present invention is not limited to this, and the signal comparison means is not limited thereto. It may be configured by a comparison circuit including an operational amplifier.

In the above embodiment, each magnetic detector 12
Differential circuit 15B that outputs output pulse signals b having different amplitudes based on the difference between the detection signals a1 and a2 from
However, the present invention is not limited to this, and an output pulse signal b having a different frequency or a different duty ratio may be output based on a difference between detection signals from the respective magnetic detectors 12. .

Further, in the above embodiment, the arithmetic unit 1
5, the electric motor 17 is driven based on the output pulse signal b output from the digital difference circuit 15B, and the steering device 18 is operated. However, the present invention is not limited to this example. Based on this, an instruction lamp provided in the cab of the vehicle 3 may be turned on to notify the driver that the vehicle 3 is out of the center of the traveling lane 1A. Also, a voice may be used instead of the instruction lamp.

[0054]

As described above in detail, according to the first aspect of the present invention, a pair of magnetic detectors for detecting magnetic flux generated from each magnet provided on the traveling road surface are symmetrical on the left and right sides of the vehicle. The detection signals output from the respective magnetic detectors are compared with each other by signal comparison means, and a digital signal whose state changes in response to the comparison result is output. Based on the digital signal, it is possible to easily detect whether the vehicle is leaning to the left or right with respect to the center of the traveling road surface. Therefore, it is possible to reduce the number of magnetic detectors, to reduce the size of the device,
The configuration can be simplified and the manufacturing cost can be reduced.

According to the second aspect of the present invention, the signal comparing means detects the detection signal output from the magnetic detector provided on the right side of the vehicle and the detection signal output from the magnetic detector provided on the left side of the vehicle. A pulse signal having a first amplitude level is output when the signal is larger than the signal, and a detection signal output from a magnetic detector provided on the left side of the vehicle is a detection signal output from a magnetic detector provided on the right side of the vehicle. Since the pulse signal having the second amplitude level different from the first amplitude level is output when it is larger than the first amplitude level, the amplitude level of the pulse signal output from the signal comparing means is equal to the first amplitude level or the second amplitude level. By simply determining whether the vehicle is at the amplitude level, it is possible to easily determine whether the vehicle is leaning to the left or right with respect to the center of the traveling road surface.

According to the third aspect of the invention, since the signal comparing means is configured to calculate the difference between the detection signals output from the respective magnetic detectors, the respective detection signals can be easily compared. .

According to the fourth aspect of the present invention, each of the magnetic detectors is provided on the vehicle so as to face the traveling road surface and detects the magnetic flux in the vertical direction generated from each of the magnets. The value of the magnetic flux detected from the detector can be accurately associated with the distance between each magnetic detector and each magnet, and the position of the vehicle in the left-right direction with respect to the center of the traveling road surface can be detected with high accuracy. Can be.

[Brief description of the drawings]

FIG. 1 is a front view showing a vehicle provided with a vehicle position detecting device according to an embodiment of the present invention and a traveling road surface on which each magnet is embedded.

FIG. 2 is an enlarged view of the magnetic detector and the like in FIG. 1 as seen from the direction of arrows II-II.

FIG. 3 is a circuit block diagram illustrating a vehicle position detecting device and the like according to the embodiment;

FIG. 4 is a characteristic diagram illustrating an output pulse signal output from a control unit in FIG. 3;

FIG. 5 is a plan view showing a vehicle provided with a vehicle position detecting device according to the related art and a traveling road surface on which magnets are embedded.

FIG. 6 is a front view of the vehicle and the traveling road surface in FIG. 5 as viewed from the direction of arrows VI-VI.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Road surface 2 Magnet 3 Vehicle 11 Vehicle position detecting device 12 Magnetic detector 15 Control unit (signal comparing means) 15A A / D conversion circuit 15B Digital difference circuit

Claims (4)

[Claims] 1. A vehicle position detecting device for detecting a position of a vehicle in a left-right direction by detecting a magnetic flux generated from a plurality of magnets located at a center of a running road surface and arranged at equal intervals in a running direction. Left and right symmetrically provided on the left and right sides of the vehicle,
A pair of magnetic detectors that output a detection signal corresponding to the magnetic flux generated from each of the magnets, and a detection signal output from each of the magnetic detectors are compared with each other, and the state changes according to the comparison result. A vehicle position detecting device, comprising: signal comparing means for outputting a digital signal. 2. The apparatus according to claim 1, wherein said signal comparing means is configured to output a signal when a detection signal output from a magnetic detector provided on a right side of said vehicle is larger than a detection signal output from a magnetic detector provided on a left side of said vehicle. A pulse signal having an amplitude level of 1 is output, and a detection signal output from a magnetic detector provided on the left side of the vehicle is larger than a detection signal output from a magnetic detector provided on the right side of the vehicle. The vehicle position detecting device according to claim 1, wherein a pulse signal having a second amplitude level different from the first amplitude level is output. 3. The vehicle according to claim 1, wherein the signal comparing unit is configured to compare the detection signals with each other by calculating a difference between the detection signals output from the magnetic detectors. Position detection device. 4. The vehicle according to claim 1, wherein each of the magnetic detectors is provided on the vehicle so as to face the traveling road surface and detects a magnetic flux in a vertical direction generated from each of the magnets. The vehicle position detecting device according to any one of the preceding claims.