JPH11108673A - Running position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a running position sensor by which a vehicle can be measured precisely by excluding the error of a lateral deviation due to rolling of the vehicle on a snow accumulated road or the like, by a method wherein an electromagnetic field marker body which is composed of a magnet group or the like buried under a road surface is detected by a magnetic field sensor which is arranged and installed at the vehicle. SOLUTION: A traveling position sensor for a vehicle is constituted, e.g. of magnetic sensors 2a, 2b inside a right sensor case 1 and a left sensor case 1 which are fixed to a front bumper 3 at a prescribed interval, of a plurality of electromagnetic field marker bodies composed of magnets 4 which are buried vertically at prescribed intervals in the width wise direction and the traveling direction of a traveling road surface 6 and of the like. The magnetic sensors 2a, 2b are provided respectively with, e.g. longitudinal and transverse Hall elements whose magnetism sensing axes are at right angles, and they are connected to circuit parts which are installed inside the sensor cases 1. Then, on the basis of signals from the respective Hall elements, the lateral deviation of the vehicle and the height of the vehicle with reference to the magnets 4 are computed, and the lateral deviation is corrected by a vehicle rolling angle computed on the basis of the height or the like of the vehicle so as to be outputted. The electromagnetic field marker bodies may be constituted of induction coils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for accurately measuring a traveling position of a vehicle relative to a sign on a bad road such as a snowy road by eliminating a calculation error of a lateral deviation due to a roll of the vehicle. The present invention relates to a travel position sensor using an electromagnetic field marker.

[0002]

2. Description of the Related Art As a conventional traveling position sensor, there is a vehicle traveling position detecting device as disclosed in Japanese Patent Application Laid-Open No. 4-288605. FIG. 11 shows an example of the present disclosure. According to the present disclosure, it is described that the magnetic sensor can determine the distance from the induction cable without depending on the roll of the vehicle by determining the vector sum of the signals of the vertical coil and the horizontal coil. I have.

[0003]

However, in such a conventional vehicle traveling position detecting device, an induction cable having a monotonous characteristic such that the magnetic flux density changes concentrically around the cable cross section must be used. Such effects cannot be expected, and it is difficult to apply the present invention to a permanent magnet having a complicated magnetic flux density distribution. In addition, the induction cable must be laid over a long distance, and the maintenance cost for dealing with the disconnection of the cable increases. In addition, if a part of the cable is broken, the function of the guide cable is lost over the entire laid road, so that the vehicle cannot run. The present invention has been made in view of such a conventional problem, and eliminates a calculation error of a lateral deviation due to a roll of the vehicle, and determines a traveling position of the vehicle with respect to a marker on a rough road such as a snowy road. An object of the present invention is to provide a traveling position sensor using an electromagnetic field marker suitable for accurate measurement.

[0004]

Therefore, in the travel position sensor according to the first aspect, a plurality of rows of electromagnetic field markers each including a group of magnets or a group of induction coils embedded in a road surface, and a direction perpendicular to the road surface. A plurality of electromagnetic field sensors arranged in the vehicle as a set of a vertical sensor for detecting the electromagnetic field of the vehicle and a width sensor for detecting the electromagnetic field in the width direction of the vehicle, and signals of the vertical sensor and the width direction sensor. Lateral deviation calculating means for calculating a lateral deviation of the vehicle with respect to the electromagnetic field marker based on the correlation; and calculating a height of the vehicle with respect to the electromagnetic field marker based on a correlation between signals of the vertical sensor and the width direction sensor. Vehicle height calculating means, a roll angle calculating means for calculating a roll angle of a vehicle based on an output of the vehicle height calculating means and a distance between the electromagnetic field sensors, and an output of the roll angle calculating means. And a lateral deviation correcting means for outputting the corrected lateral deviation. In the traveling position sensor according to the second aspect, in the traveling position sensor according to the first aspect, the electromagnetic field marker has a predetermined gap in a width direction of a traveling lane and alternates in a traveling direction of the vehicle. It is configured to be buried in.

[0005]

Hereinafter, the present invention will be described with reference to the drawings. First, the configuration will be described. FIG. 1 to FIG. 9 are diagrams illustrating Embodiment 1 of the present invention. FIG. 1 is a view for explaining the overall configuration, and shows a front bumper 3 of a vehicle.
The sensor case 1 is fixed to two lower portions of. The sensor case 1 is provided on the right side and the left side when viewed from the front of the vehicle.
a, a magnetic sensor 2b inside the left sensor case 1,
It is disposed at approximately the same height from the road surface 6 at about 15 cm and with a gap of W. Further, a circuit board (not shown) is also built in the sensor case 1. At a predetermined interval T, for example, 2 m, a magnet 4 is buried in the traveling road surface with the magnetic poles perpendicular to the road surface and the N poles facing upward. The magnetic pole is S
May be on top.

FIG. 2 shows a magnetic sensor 2 a and a magnetic sensor 2.
FIG. 4 is a front view of the structure of FIG. The vertical Hall element 5a and the horizontal Hall element 5b are fixed so that they are close to each other and their magnetic sensing axes are orthogonal to each other. 5c, 5d
Indicates the magneto-sensitive axis of each Hall element. The vertical Hall element 5
It is desirable to use a bulk element of indium antimony or indium arsenide, which has a relatively low cost, a high sensitivity, an excellent temperature characteristic, and a low noise, respectively. However, gallium arsenide, silicon,
Germanium, vapor deposition, epitaxial growth, search coil, linkage coil, and SQUID element may be used.

FIG. 3 is a block diagram of the circuit. The inputs of the vertical Hall element 5a and the horizontal Hall element 5b are supplied from a power source (not shown), and the output is differentially amplified by the differential amplifiers 8a and 8b. After that, it is transmitted to the circuit section 10 as shown by ch1 and ch2. Similarly, the output from the magnetic sensor 2b is transmitted to the circuit section 10 as indicated by ch3 and ch4. The circuit unit 10 includes an A / D converter (not shown),
Operational amplifier, CPU, ROM, RAM, clock circuit,
It is composed of a power supply circuit and the like. Further, the lateral deviation signal is D
The signal is converted into an analog signal by the / A converter 9 and transmitted to a vehicle control circuit (not shown).

Next, the operation will be described. FIG. 4 is a flowchart showing the flow of the entire signal processing. The operation of each unit will be described below with reference to the flowchart. First, the magnetic sensor 2a and the magnetic sensor 2b have a built-in vertical Hall element 5a and a horizontal Hall element 5b, respectively. Is input to In S10, ch1 to ch
The signals of the four systems up to 4 are digitally converted by the A / D converter 10 of the circuit unit 10. In S20, it is determined whether or not a peak is present based on the history of the maximum signal of the vertical hall element 5a. When it is a peak, it can be determined from the fact that the signal history becomes maximum. If it is not the peak, the process returns to S10 to perform A / D conversion again. Note that the process of S20 is performed independently by the magnetic sensor 2a and the magnetic sensor 2b, and the sensor signal whose peak arrives earlier is prioritized as the peak.

Before explaining S30, the correlation between the magnetic flux density distribution of the magnet and the map will be described with reference to FIGS. FIG. 5 shows a predetermined distance h on the pole axis of the magnet.
FIG. 5 is a diagram showing a method of measuring magnetic flux densities in horizontal and vertical directions when the magnetic flux density passes through. Here, 4a is a line of magnetic force.
FIG. 6 shows the magnetic flux density of the vertical Hall element 5a when the distance h is changed when the variable lateral displacement amount Y is varied via the distance h as shown in the figure. As shown in FIG. 6, when the lateral displacement amount Y is different, the magnetic flux density changes even at the same distance h. Further, when the distance h is different, the magnetic flux density changes even with the same lateral displacement amount Y. Therefore, in order to obtain the lateral displacement amount Y independent of the change in the distance h, it is necessary to use the map shown in FIG. FIG. 7 is a diagram for explaining a map for obtaining the lateral shift amount Y independent of the change in the distance h. A symbol from A to E is attached according to the lateral displacement amount Y in FIG. 5, and a number from 0 to 2 is attached according to the distance h.
In combination, 15 combinations of the lateral displacement amount Y and the distance h are created from A0 to E0, A1 to E1, and A2 to E2. If the distance h is small, a locus from A0 to E0 is drawn according to the lateral displacement amount Y. Next, when the distance h is intermediate, the trajectory from A1 to E1 is drawn according to the lateral displacement amount Y. Next, the distance h
Is large, a trajectory from A2 to E2 is drawn according to the lateral displacement amount Y. This figure is subdivided and the value of the lateral deviation with respect to the magnetic flux density of the vertical Hall element 5a and the horizontal hole 5b is written in the memory, and if a map is created, an accurate lateral deviation independent of the distance h can be obtained. It becomes possible to get out at high speed. FIG. 8 is a diagram for explaining a map for obtaining a distance h that does not depend on a change in the lateral displacement amount Y. Similarly to the above, a combination of the lateral displacement amount Y and the distance h of 15 from A0 to A2, B0 to B2, and E0 to E2 is created. The lateral displacement amount Y is 0
In the case of, the trajectory from A0 to A2 is drawn as the distance h increases. Next, when the lateral displacement amount Y is intermediate, a locus from C0 to C2 is drawn as the distance h increases. This figure is subdivided, and the value of the distance h with respect to the magnetic flux density of the vertical Hall element 5a and the horizontal Hall element 5b is written in the memory, and if a map is created, the accurate distance h is independent of the lateral displacement. At high speed. In the present embodiment, the linear conversion is performed using the map because the relationship between the lateral displacement amount Y and the distance h is strongly nonlinear due to the relationship of the magnetic field characteristics of the magnet, but the vertical Hall element 5a and the horizontal Hall element are used. Needless to say, if the shape and material are devised so that the linear relationship between the magnetic flux density of 5b and the amount of lateral displacement Y and the distance h is strengthened, the conversion may be performed linearly using mathematical expressions.

As described above, in S30, the signals of the vertical Hall element 5a and the horizontal Hall element 5b of the magnetic sensor 2a are projected on a map to determine the horizontal deviation Y1. Subsequently, in S40, the signals of the vertical Hall element 5a and the horizontal Hall element 5b of the magnetic sensor 2b are projected on a map to determine the horizontal deviation Y2. Further, in S50, the signals of the vertical Hall element 5a and the horizontal Hall element 5b of the magnetic sensor 2a are projected on a map to determine the distance Z1. Subsequently, in S60, the signals of the vertical Hall element 5a and the horizontal Hall element 5b of the magnetic sensor 2b are projected on a map to determine the distance Z2.

Next, in S70, each roll of the vehicle θ
Is calculated. FIG. 9 is a configuration diagram for explaining a method of obtaining the roll angle of the vehicle. Let L be the distance between the magnetic sensor 2a and the magnetic sensor 2b. Further, the roll angle θ of the vehicle can be obtained by the following calculation using the distances Z1 and Z2 obtained in S50 and S60. θ = arcTan ((Z2-Z1) / L) ‥‥‥‥ (1)

In step S80, the roll angle θ is obtained by using the roll angle θ obtained by the equation (1), and by using the lateral displacement Y1 and the lateral displacement Y2 in the magnetic sensor 2a and the magnetic sensor 2b obtained in S30 and S40. Eliminate deviation errors.
The method of removing the deviation of the lateral deviation due to the roll is represented by the following equation, where the roll error of Y1 is ΔY1, the roll error of Y2 is ΔY2, and the lateral deviation after the roll correction is Y. The roll error ΔY1 = Z1 * tan (θ) of Y1 The roll error ΔY2 = Z2 * tan (θ) of Y2, the lateral deviation Y after the roll correction is Y = ((Y1−ΔY1) + (Y2− ΔY2)) / 2 ‥‥‥‥ (2) In S80, the lateral deviation Y after the roll correction by the equation (2) is D / A-converted and output from the D / A converter 9 in S90.

As described above, in the traveling position sensor according to the present embodiment, the magnet 4 embedded in the road surface 6 is used.
, A vertical Hall element 5a for detecting an electromagnetic field in a direction perpendicular to the road surface 6 and a horizontal Hall element 5b for detecting an electromagnetic field in the width direction of the vehicle are provided as a set to the vehicle. Magnetic sensor 2a and magnetic sensor 2b provided
A lateral deviation calculating means for calculating a lateral deviation of the vehicle with respect to the electromagnetic field marker based on a signal correlation between the vertical hall element 5a and the horizontal hall element 5b; Vehicle height calculating means for calculating the height of the vehicle with respect to the electromagnetic field marker based on the correlation of the signal with the hall element 5b; and the output of the vehicle height calculating means and the distance between the magnetic sensor 2a and the magnetic sensor 2b. The circuit unit 10 includes a roll angle calculating means for calculating the roll angle of the vehicle and a lateral deviation correcting means for outputting a lateral deviation corrected based on the output of the roll angle calculating means. The electromagnetic field marker according to the present invention can eliminate the lateral deviation error due to the roll of the vehicle as in the case of the guide cable.
In addition, since the electromagnetic field marker using the magnet 4 can be used, the maintenance cost for coping with the disconnection of the cable or the like can be reduced. In addition, since the cable is not broken, there is an effect that the danger that the vehicle cannot travel can be eliminated over the entire road where the electromagnetic field sign is laid. In addition, 2
Since the row of electromagnetic field markers is used, even if one of the sensors fails, the running function of the vehicle can be preserved using the sensor that has not failed.

Next, a second embodiment will be described. FIG. 10 is a view for explaining the overall configuration of the second embodiment of the present invention, in which magnets 4 are embedded alternately in the traveling direction of the vehicle. Other configurations and operations are the same as those of the first embodiment.

As described above, in the traveling position sensor according to the present embodiment, in the traveling position sensor according to the first aspect, the electromagnetic field marker has a predetermined gap W in the width direction of the traveling lane. In addition, since it is configured to be buried alternately in the traveling direction of the vehicle, even with the electromagnetic field marker using the magnet 4, the error of the lateral deviation due to the roll of the vehicle can be eliminated as in the case of the guide cable. In addition, since the electromagnetic field marker using the magnet 4 can be used, the maintenance cost for coping with the disconnection of the cable or the like can be reduced. Further, since the cable is not broken, there is obtained an effect that the danger that the vehicle cannot travel can be eliminated throughout the laying of the electromagnetic field sign. Furthermore, since two rows of electromagnetic field markers are used,
Should any of the sensors fail, the running function of the vehicle can be preserved using the sensors that have not failed. Furthermore, the number of electromagnetic field markers can be reduced, and cost can be reduced. In each of the embodiments, the description has been made assuming that the marker is a magnet and the electromagnetic field sensor is a magnetic sensor such as a Hall element, but the marker is an induction coil, and the electromagnetic sensor is Alternatively, the magnetic field distribution of the induction coil may be measured.

[0016]

As described above, according to the traveling position sensor of the present invention, the vehicle travels with respect to the sign on a rough road such as a snowy road by eliminating the error of the lateral deviation due to the roll of the vehicle. The position can be measured accurately. In addition, no laying cost and no maintenance cost are required when the guide cable is laid, and there is no danger that the vehicle will not be able to travel due to the break of the guide cable. Also, even if one of the sensors fails, the traveling function of the vehicle can be preserved by using an electromagnetic field sensor that has not failed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an entire configuration of a traveling position sensor according to a first embodiment;

FIG. 2 is a diagram showing a structure of a magnetic sensor.

FIG. 3 is a block diagram of a circuit.

FIG. 4 is a flowchart showing the flow of the entire signal processing.

FIG. 5 is a diagram illustrating a method of measuring magnetic flux densities in a horizontal direction and a vertical direction when a predetermined distance h is interposed on a magnetic pole axis of a magnet.

FIG. 6 is a diagram in which the magnetic flux density of the vertical Hall element 5a is changed with the distance h when the lateral shift amount Y is varied via the distance h.

FIG. 7 is a diagram illustrating a map for obtaining a lateral shift amount Y independent of a change in a distance h.

FIG. 8 is a diagram illustrating a map for obtaining a distance h that does not depend on a change in a lateral displacement amount Y.

FIG. 9 is a configuration diagram for explaining a method of obtaining a roll angle of a vehicle.

FIG. 10 is a diagram illustrating an overall configuration of a traveling position sensor according to a second embodiment.

FIG. 11 is a diagram showing a conventional traveling position sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor case 2a Magnetic sensor 2b Magnetic sensor 3 Front bumper 4 Magnet 4a Magnetic field line 5a Vertical hall element 5b Horizontal hall element 5c Vertical hall element magnetic sensing axis 5d Horizontal hall element magnetic sensing axis 6 Road surface 8a Differential amplifier 8b Differential amplifier 9D / A converter 10 circuit part

Claims (2)

[Claims] 1. A plurality of rows of electromagnetic field markers consisting of a group of magnets or induction coils embedded in a road surface, a vertical sensor for detecting an electromagnetic field in a direction perpendicular to the road surface, and detecting an electromagnetic field in a width direction of a vehicle. A plurality of electromagnetic field sensors arranged in the vehicle as a set of width direction sensors to be set, and a lateral displacement for calculating a lateral deviation of the vehicle with respect to the electromagnetic field marker based on a correlation between signals of the vertical sensor and the width direction sensor. A displacement calculating means,
Vehicle height calculating means for calculating the height of the vehicle relative to the electromagnetic field marker based on the correlation between the signals of the vertical sensor and the width direction sensor; and based on the output of the vehicle height calculating means and the distance between the electromagnetic field sensors. A travel position sensor comprising: a roll angle calculating means for calculating a roll angle of a vehicle; and a lateral deviation correcting means for outputting a lateral deviation corrected based on an output of the roll angle calculating means. 2. The travel position according to claim 1, wherein the electromagnetic field sign has a predetermined gap in a width direction of a traveling lane and is buried alternately in a traveling direction of the vehicle. Sensor.