JPH1194566A - Traveling position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling position sensor not influenced by the sensitivity change of a sensor. SOLUTION: The sensors (1-5) mounted on a vehicle with a prescribed interval respectively detect magnetic components in directions perpendicular to a road surface and horizontal to the vehicle. A sensor selection part 7 compares the detection output of the respective sensors and selects the sensor with the maximum detected value of vertical magnetic components and a peak judgement part 8 judges whether or not the detection output of the selected sensor is at a peak. A distance computing part 9 projects the detected value of the sensor adjacent to the sensor whose detected value is judged as at the peak across a magnetic source to a built-in distance detection map and obtains the horizontal direction distance of the sensor to the magnetic source. A horizontal displacement amount computing part 10 computes the horizontal displacement amount of the vehicle by a horizontal direction distance detected value and the position at the vehicle of the sensor. A deviation is generated when computed values by the two sensors do not match, however, the horizontal displacement amount computing part 10 computes and obtains the position on an output characteristic line by the proportional relation of the deviation of both sensors and a corresponding voltage is outputted by an output part 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel position sensor that is mounted on a vehicle and detects a magnetic sign placed on a road on which the vehicle travels as road information.

[0002]

2. Description of the Related Art Conventionally, as a traveling position sensor, for example, a traveling information collecting device for a vehicle disclosed in Japanese Patent Application Laid-Open No. H8-161036 has been provided. The outline is shown in FIG. Magnetic markers 101a to 101d and 102a to 102d are provided on both left and right sides of the lane in which the vehicle travels at predetermined intervals so as to face each other. Vehicle 2 running on the lane
At 00, the magnetic sensors 103a, 10a
3b is provided, which sequentially passes the magnetic field of the magnetic marker as the vehicle travels, and detects the magnetic flux density.

When a vehicle is traveling in the center of a lane,
Both magnetic sensors detect the same magnetic flux density. However, when the magnetic sensors deviate from the center, the magnetic sensors on the side of the deviation approach the magnetic marker and detect a large magnetic flux density. The information collecting device calculates the lateral displacement of the vehicle from the detected value of the magnetic flux density with reference to the magnetic marker on the magnetic sensor side having a large detected value. Thus, even if the vehicle is largely displaced, the amount of deviation of the vehicle can be detected without losing sight of the magnetic sign.

[0004]

However, it is conceivable that the magnetic marker has a variation in magnetic pole strength and the distribution of magnetic flux density is distorted in a roadbed provided with a reinforcing bar. The change in the magnetic flux density is directly calculated as a lateral deviation of the vehicle, and is a deviation. When a deviation occurs in the amount of lateral deviation of the vehicle, there is a problem that a sudden change or the like adversely affects the vehicle steering in automatic driving or unmanned driving performed based on the correction of the lateral deviation.

Further, since the deviation of the lateral deviation of the vehicle is reflected as a change in the detection sensitivity of the magnetic sensor, when the vehicle is deviated to the opposite side and the magnetic sensor is switched, if the detection sensitivity is different, the detection value will be different. There is a problem in that a level difference occurs in the connection, which causes a sudden change in the vehicle steering and that the steering control of the vehicle diverges. The present invention has been made in view of the above-described conventional problems, and provides a traveling position sensor that can automatically correct a deviation caused by a change in magnetic flux density and detect a lateral deviation amount of a vehicle without changing detection characteristics even when a magnetic sensor is switched. It is intended to provide.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a magnetic field marker buried on a road surface along a traveling lane, a vertical sensor disposed on the vehicle and detecting a magnetic field in a direction perpendicular to the road surface, A horizontal sensor disposed in the vehicle and detecting a magnetic field in the horizontal and horizontal directions of the vehicle, the horizontal deviation of the vehicle with respect to the magnetic marker is calculated based on the correlation between the output signal of the vertical sensor and the output signal of the horizontal sensor. In the travel position sensor obtained by the calculation based on the above, a plurality of the vertical sensors and the horizontal sensors are arranged as a sensor pair at a predetermined interval in a width direction of the vehicle, and the magnetic field marker is sandwiched by the magnetic marker. Calculated from the output signals of the sensor pair 1 and the sensor pair 2 closest to the vehicle, and the lateral deviation of the vehicle when the magnetic field marker is positioned directly below the sensor pair 1 and the sensor pair 2. Based on the position value It was assumed to determine the lateral deviation of the vehicle by the arithmetic expression.

[0007] The predetermined arithmetic expression is that the lateral deviation values of the vehicle when the magnetic marker is located immediately below the sensor pair 1 and the sensor pair 2 are A1 and B1, respectively, and the sensor pair 1 and the sensor pair 2 When the magnetic marker is positioned therebetween, the lateral deviation values of the vehicle determined based on the output signals of the sensor pair 1 and the sensor pair 2 are A2 and B2, respectively, and the vehicle is a calculation result of the predetermined calculation expression. Let Y be the lateral deviation value of Y = A1 + (A2-A1) / [[(B2-B1) + (A
2-A1)] · (B2-A1)]. .

[0008] The predetermined arithmetic expression is that the lateral deviation values of the vehicle when the magnetic marker is located directly below the sensor pair 1 and the sensor pair 2 are A1 and B1, respectively, and the sensor pair 1 and the sensor pair 2 When the magnetic marker is positioned therebetween, the lateral deviation values of the vehicle determined based on the output signals of the sensor pair 1 and the sensor pair 2 are A2 and B2, respectively, and the vehicle is a calculation result of the predetermined calculation expression. If Y is the lateral displacement value of Y, then Y = A1 + β · B2 + (1-β) · A2β = (A2-A1) / (B2-A1).

The magnetic markers may be arranged with different magnetic polarities, and the lateral displacement of the vehicle may be calculated only at a predetermined location based on the polarity information of the magnetic markers.

[0010]

A pair of sensors provided in the width direction of the vehicle detects a magnetic field in a direction perpendicular to the road surface and a magnetic field in the lateral direction of the vehicle, and the lateral distance between the pair of sensors and the magnetic marker is detected based on a correlation between the detected magnetic fields. Is done. Therefore, if the mounting position of the sensor pair in the vehicle is added or subtracted, the lateral deviation of the vehicle with respect to the magnetic marker is detected. When the sensor pair detects it just above the magnetic sign, it is not affected by the fluctuation of the magnetic intensity, so the lateral displacement of the vehicle calculated based on the detected value is not affected by the magnetism. It is a fixed point.

[0011] Therefore, two adjacent magnetic marker bodies are interposed therebetween.
The magnetic flux density is detected by one sensor pair, and the lateral deviation detected value of two vehicles calculated based on the detected value is placed on a continuous line connecting the fixed points of the respective sensor pairs. By projecting the deviation detection value and outputting a value from the continuous line, a lateral deviation of the vehicle which is not affected by the magnetic fluctuation is detected. As the sensor pair uses two sensor pairs adjacent to each other with the magnetic marker interposed therebetween, it can be easily specified by the magnitude of the output.

[0012]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a block diagram showing the configuration of the embodiment. The sensor 1, the sensor 2, the sensor 3, the sensor 4, and the sensor 5 are magnetic sensors each having a detection axis as a sensor pair in two directions perpendicular to the road surface and in the horizontal and horizontal directions of the vehicle, and are connected to the input circuit 6. The input circuit 6 inputs the detection output of the sensor in accordance with the command of the peak determination unit 8, and inputs each sensor in a time-division manner. The input value is further subjected to A / D conversion and output.

The input circuit 6 is connected to a sensor selection unit 7, a peak determination unit 8, and a distance calculation unit 9. The sensor selection unit 7 compares the detection outputs of the sensors and selects the sensor having the maximum detection output of the magnetic field perpendicular to the road surface. The peak determination unit 8 stores the detection output of each sensor, and determines from the history thereof whether or not the detection output of the vertical magnetic field of the sensor selected by the sensor selection unit 7 is a peak. Based on the result of the determination, control is performed by deciding whether to input the next detection signal from the input circuit 6 or to calculate the lateral deviation of the vehicle.

The distance calculation unit 9 temporarily stores the detection output of each sensor, and when the calculation of the lateral deviation of the vehicle is determined, the distance calculation unit 9 is adjacent to the sensor selected by the sensor selection unit 7 across the magnetic marker. The detected output of the sensor is projected on a built-in distance detection map, and the lateral distance between the sensor and the magnetic marker is determined. The lateral displacement calculator 10 calculates the lateral displacement of the vehicle by a predetermined calculation based on the lateral distance between the two sensors. The output unit 14 performs D / A conversion on the calculated lateral deviation amount of the vehicle and outputs the result.

FIG. 2 is a diagram showing the structure of the sensors (1 to 5). That is, the sensors (1 to 5) have the same configuration,
The horizontal sensor a is in charge of detecting the magnetic field in the horizontal and horizontal directions of the vehicle, and the vertical sensor b is in charge of detecting the magnetic field perpendicular to the road surface, and outputs the detected values via differential amplifiers Da and Db, respectively. As the horizontal sensor a and the vertical sensor b, for example, Hall elements arranged at right angles as shown in FIG. 3 are used, and the Hall elements are provided with a magnetic detection axis indicated by an arrow in a direction perpendicular to the road surface and in a horizontal and horizontal direction of the vehicle. Used.

As a Hall element, the cost is relatively low.
A bulk element of indium antimony or indium arsenide, which has high sensitivity and excellent temperature characteristics and has low noise, is used. In addition, it is also possible to use gallium arsenide, silicon, germanium, vapor deposition, epitaxial growth, magnetoresistive elements, search coils, linkage coils, and SQUID elements.

As shown in FIG. 4, the sensors (1 to 5) are mounted in the sensor case 20 below the front bumper of the vehicle 200 at intervals of, for example, 20 cm and at a height substantially equal to 15 cm with respect to the road surface. Is done. The detection radius of the sensor is set to a range up to an adjacent sensor as a detection range, and is set to 20 cm when the sensor position is set as described above. Thereby, the magnetic marker can be detected by the two sensors simultaneously. A predetermined interval T (for example, 2
In M), a magnetic marker 100 is embedded with the magnetic pole perpendicular to the road surface and the N pole facing upward.

Next, the flow of detection of the lateral displacement of the vehicle with respect to the magnetic marker will be described with reference to the flowchart of FIG. First, in step 100, the input circuit 6 inputs detection values of the sensors 1 to 5 in an initial state in a time division manner, performs A / D conversion on the input values, and outputs the result. In step 101, the sensor selection unit 7 compares the magnetic field detection output of each sensor in a direction perpendicular to the road surface, and selects the sensor that has detected the maximum vertical magnetic field. This processing is for specifying the sensor closest to the magnetic marker for calculation of the amount of lateral deviation.

FIG. 6 is a diagram showing, from the top, how the vehicle 200 passes on the traveling line formed by the magnetic marker 100, and the regions (11, 22, 33, 44, 55) correspond to the sensors (1, 2). 2, 3, 4, 5). When the vehicle 200 travels in the direction A, output voltages as shown in FIG. 7 are obtained from the sensors. Since the magnitude of the output indicates the approaching distance to the magnetic marker, the point at which the peak value is detected is determined when the vehicle 200 detects the magnetic marker 10.
In this state, the sensor is closest to zero and the sensor is right beside the magnetic marker 100. The sensor having the largest peak value (sensor 3) is located at the closest distance to the magnetic marker.

Therefore, by calculating the distance in the lateral direction using the detection output of the sensor having a large peak, the location of the magnetic marker can be determined, and if a predetermined value based on the mounting position of the sensor on the vehicle is added, the vehicle can be obtained. Is obtained. Also, if two adjacent sensors detect the same detection value, they will be at the same distance from the magnetic marker,
Either of the two sensors can be used to calculate the lateral deviation of the vehicle.

In step 102, the peak judging section 8 checks whether or not the detected value of the vertical magnetic field of the sensor selected by the sensor selecting section 7 has peaked. If not, it is determined that the sensor has not reached the side of the magnetic marker, and the process returns to step 100 to output a command to input a new detection output. If it is a peak, the process proceeds to step 103 because the lateral distance between the sensor and the magnetic marker can be detected from the side of the magnetic marker.

In step 103, the distance calculation section 9 projects the detection output of the sensor having the largest detection value onto the distance detection map so as to calculate the lateral distance of the sensor from the magnetic marker. The map shown in FIG. 8 is used as the distance detection map. The map in FIG. 8 includes a plurality of distance lines (A, B, C, D, and E), and the lateral distance can be detected based on the projection position of the detection output of the sensor.

FIG. 9 is a diagram showing the principle of measuring the magnetic flux densities in the horizontal and vertical directions when the magnetic pole axis of the magnet is separated by a vertical distance h. The sensor 40 has a magnetic detection axis set in a direction indicated by arrows g and p. FIG. 10 shows changes in the density of the vertical component and the horizontal component of the magnetic flux emitted from the magnetic marker 30 when the lateral distance is changed. As shown in FIG. 10, the vertical distance h is strongly related to the relationship between the horizontal distance and the magnetic flux density as a parameter.

Therefore, when the distance between the sensor and the road surface is fixed, the lateral distance can be obtained based on the same curve as the mounting height of the sensor in the vehicle as shown in FIG. However, in consideration of the fact that the distance between the sensor and the road surface changes due to the loading of the vehicle or vertical vibration, etc., a more accurate lateral deviation amount can be detected by a distance detection map independent of the change in the distance h shown in FIG. Is required.

Next, the creation of the distance detection map will be described. First, symbols from A to E are given according to the horizontal distance in FIG. 9, numbers from 0 to 2 are given according to the vertical distance h, and 15 horizontal distances from A0 to E0, A1 to E1, and A2 to E2 sequentially. And a vertical distance h. When the vertical distance h is small, a locus from A0 to E0 is drawn according to the horizontal distance as shown in FIG. Next, when the distance is intermediate, a locus from A1 to E1 is drawn. If the distance h is large, a locus from A2 to E2 is drawn.

Therefore, the continuous lines A, B0, A0 of A0, A1, A2
B1, B2 connecting lines B, C0, C1, C2 connecting lines C, D
A connecting line D of 0, D1, D2 and a connecting line E of E0, E1, E2 are the respective distance lines, and the horizontal distances A, B, C, D, independent of the vertical distance h from the lines. E is required. The distance h is obtained by the correlation between the vertical magnetic field and the horizontal magnetic field.
By writing a distance detection map that does not depend on the data on the memory and projecting the detected values of the vertical magnetic field strength (magnetic flux density) and the horizontal magnetic field strength (magnetic flux density) onto the map, the unique lateral distance can be quickly obtained. it can. Note that, here, linear conversion is performed using a map because the relationship between the horizontal distance and the vertical distance h has a strong nonlinearity due to the magnetic field characteristics of the magnet. If the shape and material of the magnet are devised so that the relationship between the horizontal distance and the vertical distance h is linear, it is needless to say that the conversion may be performed linearly using mathematical formulas. In this case, the memory for storing the map is omitted.

In step 104, the distance calculator 9 determines the lateral distance between the magnetic marker and the sensor from the distance line on which the detection output of the sensor is projected, and outputs a detection voltage corresponding to the distance. In the above processing, the lateral distance of the sensor closest to the magnetic marker is detected. Therefore, if a predetermined voltage is added according to the mounting position of the sensor on the vehicle, the amount of lateral displacement of the vehicle with respect to the magnetic marker can be obtained. For example, if the sensor 5 is selected, since this sensor is deviated to the right by 40 cm with respect to the center sensor 3, a voltage corresponding to 40 cm is subtracted corresponding to the detection sensitivity of the sensor.

Similarly, when sensor 1, sensor 2, sensor 3, and sensor 4 are selected, 40 cm addition, 20 cm addition,
By adding or subtracting 20 cm and adding or subtracting the voltage corresponding to the position of each sensor, when the vehicle is laterally displaced from the right 50 cm to the left 50 cm with respect to the magnetic marker, for example, from -5 V to +5 V A smooth displacement signal can be output according to the displacement. However, when affected by a variation in the solid state of the magnetic marker or a magnetic body such as a reinforcing bar, the magnetic flux density distribution is distorted, and the lateral distance detected by the sensor is different from the actual one, causing a deviation. This deviation also causes a step in the connection of the detection signals when the sensor is switched.

The following processing aims at eliminating the deviation caused by the fluctuation of the magnetic flux density and preventing the occurrence of a step. First, in step 105, the distance calculation unit 9 projects the detection output of an adjacent sensor having the largest output next to the sensor whose maximum peak value is output on the distance detection map. In step 106, the lateral distance between the magnetic marker and the sensor is obtained from the distance line on which the detection output of the sensor is projected, and a voltage corresponding to the distance is output.

As described above, the lateral distances f1 and f2 between the sensors adjacent to each other with the magnetic marker interposed therebetween are detected. Since the distances f1 and f2 are lateral distances obtained from both the left and right sides of the magnetic marker, if the distribution of the magnetic flux density does not fluctuate in the magnetic marker, the sum is the distance between the two sensors.

However, if the distribution of the magnetic flux density fluctuates, the distance value obtained by projecting it on the distance detection map will have an error. On the other hand, when the sensor passes directly above the magnetic marker, distance detection can be performed without being affected by fluctuations in magnetic intensity, as shown in the distance detection map of FIG. Therefore, for example, when calculating the lateral deviation amount of the vehicle with the characteristic shown by the α line in FIG. 11, if the lateral deviation amount of the vehicle obtained from the detection value of each sensor is projected on the α line, there is no deviation. Detection characteristics can be obtained. As a result, a detection characteristic in which a step does not occur even when the sensor is switched is obtained.

That is, as shown in FIG. 11, each of the sensors (1 to 5) is plotted on a line α indicating the detection characteristic of the lateral deviation amount of the vehicle.
Does not produce a deviation in the detection value when it is detected directly above the magnetic label, so that an output voltage is obtained as shown by the line α. A0, B0, C0, D0, and E0 are sensors (1 to
5) is the lateral displacement of the vehicle when it is detected just above the magnetic marker, and is a fixed point. On the other hand, when the magnetic flux density fluctuates, for example, to the higher side, the absolute value of the output voltage of each sensor changes according to the distance between the sensor and the magnetic marker as shown by a line α.
, And a deviation occurs in the lateral deviation detection value of the vehicle.

Next, a calculation method for eliminating the deviation will be described with reference to FIG. FIG. 12 shows the sensor 4 and the sensor 5 in FIG. As in FIG. 11, the vertical direction is the output voltage representing the lateral deviation, and the lateral direction is the lateral deviation of the vehicle. The line α represents an output characteristic without a deviation or a step. D indicates the detection characteristic of the sensor 4, and E indicates the detection characteristic of the sensor 5. D0 and E0 are sensors 4 and 5
Is a detected value of the lateral deviation of the vehicle that has detected it just above the magnetic marker, and is a fixed point that is not affected by the fluctuation of the magnetic flux density. F
Is an offset voltage corresponding to the sensor interval.

Here, for example, when the magnetic marker is detected at the position M, the lateral deviation calculation result of the vehicle is obtained by using the detection voltage of the sensor 4 and the lateral deviation calculation result of the vehicle is obtained by using the detection voltage of the sensor 5. The result of the position calculation becomes E3, which has a deviation from the line α. The following calculation is performed to reduce the deviation to zero.

First, if the sensor 4 and the sensor 5 are affected by a reinforcing bar or the like under the same conditions, the change amounts of the sensitivity are the same, so that the lines D and E indicating the detection characteristics are always parallel. Therefore, the M position of the magnetic marker is the sensor 4 and the sensor 5
The following equation always holds, regardless of where Since triangles D0, D2, D3 and triangles E0, E2, E3 are similar, ΔD3 / ΔE3 = (D0−D2) / (E3-E2) (1) Similarly, triangles D0, A3, D2 and triangle E0, E4, A
(D0−D2) / (E3-E2) = F3d / F3e (2) From equations (1) and (2), ΔE3 / ΔD3 = F3d / F3e F3e = F−F3d and ΔE3 / ΔD3 = (F / F3d) −1 (ΔE3 / ΔD3) + 1 = (F / F3d) F3d = ΔD3 / [(ΔE3 + ΔD3) × F]

Therefore, if the voltage at the point DO is added to the voltage represented by F3d, a lateral deviation detection value of the vehicle with no deviation can be obtained. The voltage at the point DO is an offset value F representing the distance between the sensor 4 and the sensor 3 which is the center of the vehicle. The next step is a process for performing the above calculation. That is, in step 107, a predetermined voltage is added to the detection output of the sensor obtained in the above processing according to the position of the sensor. As a result, when there is no change in the magnetic flux density,
When the sensor detects the magnetic label directly above the magnetic label, the detection characteristic does not produce a deviation as shown by the line α,
The lateral displacement of the vehicle can be detected. Except for the cases described above, deviations and steps occur as indicated by the thick lines in the detection characteristics.

In step 108, when the sensor whose output is required in the above processing detects the magnetic marker just above the sensor, the detected value can be output as if there is no deviation. When a magnetic marker is detected between the two sensors, a calculation process for eliminating the deviation is applied. First, the detection outputs A2 and B2 of the two sensors and the output voltages A1 and A2 when the magnetic marker is located immediately below the sensors.
Perform subtraction with 2. The sensitivity variation of the sensor can be determined from the subtraction value. Next, by substituting the subtraction value into the equation (3), a deviation voltage Y corresponding to the lateral deviation amount of the vehicle is detected. Y = A1 + (A2-A1) / [[(B2-B1) + (A2-A1)] · (B2-A1)] (3)

As a result, even if the detection sensitivity of the sensor due to a disturbance magnetic body such as a reinforcing bar changes, the detection characteristic is maintained as shown by the line α without causing a deviation in the detection of the lateral deviation of the vehicle. Also, instead of substituting into the above equation (3),
Β is obtained by substituting the detection outputs A2 and B2 of both sensors and the output voltages A1 and B1 when there is a magnetic marker directly below the sensors and the result of subtraction into equation (4). The same characteristics as described above can be obtained by substituting the calculated value of β, the output voltage A1 in the case where the magnetic marker is immediately below the sensor and the detection outputs A2 and B2 of both sensors into the equation (5). β = (A2-A1) / (B2-A1) (4) Y = A1 + β · B2 + (1-β) · A2 (5)

A1 is the output of the sensor closest to the magnetic marker, and A2 is the sensor output on the opposite side of the magnetic marker. B1 is the output when the sensor closest to the magnetic marker detects the magnetic marker just above the magnetic marker. B2 is the output when the sensor on the opposite side of the magnetic marker label detects the magnetic marker just above the magnetic marker marker. A1, A2, B1, B2
Respectively correspond to D0, E0, D3, and E3 in FIG. In addition to the above arithmetic expressions, for example, by calculating the average of the signals of the adjacent sensors or outputting the lateral deviation detection values of the two sensors through a low-pass filter, the joint of the signals is obtained. Can be reduced. Alternatively, when the sensor is switched, a function called a sigmoid function using a logarithmic relationship that smoothly combines two signals is used, which gradually approaches the output value of the sensor over time.

Next, a second embodiment will be described. In this embodiment, the magnetic polarity of the magnetic marker is coded, and the location is recognized so that the method of detecting the lateral deviation of the vehicle can be selected. As described above, the lateral displacement of the vehicle can be detected based on the detection output of the single sensor and the mounting position of the sensor on the vehicle. This method has a detection effect that does not take much time due to the simplicity of processing, although a deviation occurs in the detection value. Therefore, in a traveling place where high-speed traveling is possible, if the non-deviation detection is switched to this method, the divergence of the steering control due to a signal delay can be prevented without using an element having a high calculation speed.

Therefore, the magnetic polarity of the magnetic marker buried in a place where the vehicle can run at high speed is coded with different magnetic polarities in a predetermined pattern, and the sensor uses the magnetic polarity obtained in the process of detecting the lateral deviation of the vehicle. Then, the driving place is detected by pattern recognition, and a lateral deviation detecting method suitable for the road condition is selected.

FIG. 13 is a flowchart showing the flow of the detection. Steps 200 to 204 calculate the lateral direction between the sensor and the magnetic marker based on the detection output of the sensor having the largest peak value among the sensors, similarly to steps 100 to 104 of the first embodiment. Step 20
In step 5, the detected magnetic polarity of the magnetic marker is stored.

In step 206, the detection signals of the two adjacent sensors should be combined based on the above equation according to the stored example of the polarity, or the lateral deviation calculation is performed using the detection signal of one sensor alone. Is determined. For example, if the polarity pattern of the magnetic marker at the place to be combined is defined by SNNSS and a 5-bit code, the combining process is performed if the stored magnetic polarity string pattern of the magnetic marker passed in the past is SNNSS. Proceed to step 207 to perform.

Steps 207 to 211 calculate the lateral displacement of the vehicle by combining the signals for eliminating the deviation by using the outputs of the adjacent sensors as in steps 105 to 109 of the first embodiment. The detection voltage representing the calculated value is D /
A-converted and output. The pattern of the magnetic polarity row is SNNS
If it is not S, a predetermined voltage corresponding to the position of the sensor is added to the signal of the single sensor in step 212 to determine the lateral deviation of the vehicle.
Converted and output.

The present embodiment is configured as described above, and by limiting the place where the coupling processing for eliminating the deviation in the detection signal is performed, the steering control can be prevented from diverging without using a high-operation speed element. Be done

[0046]

According to the present invention, a pair of sensors provided in the width direction of the vehicle detects a magnetic field in a direction perpendicular to the road surface and a magnetic field in the lateral direction of the vehicle, and the lateral distance between the pair of sensors and the magnetic marker is determined by the correlation between the detected magnetic fields. Is detected. Therefore, if the mounting position of the sensor pair in the vehicle is added or subtracted, the lateral deviation of the vehicle with respect to the magnetic marker is detected. When the sensor pair detects it just above the magnetic sign, it is not affected by the fluctuation of the magnetic intensity, so the lateral displacement of the vehicle calculated based on the detected value is not affected by the magnetism. It is a fixed point.

Therefore, two adjacent magnetic labels are interposed.
Detected by one sensor pair, and the lateral deviation detection value of two vehicles calculated based on the detected value is detected on a continuous line connecting the fixed points of the respective sensor pairs with the lateral deviation detection of either vehicle By projecting the value and outputting the value from the connection line, the lateral deviation of the vehicle which is not affected by the magnetic fluctuation is detected. Since the sensor pair uses two sensor bodies adjacent to each other with the magnetic marker interposed therebetween, it can be easily specified by the magnitude of the output without requiring complicated processing.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment.

FIG. 2 is a diagram showing a configuration of a sensor.

FIG. 3 is a diagram showing a configuration when a sensor is a Hall element.

FIG. 4 is a diagram showing a positional relationship between a sensor and a magnetic marker when the sensor is mounted on a vehicle.

FIG. 5 is a flowchart for detecting a lateral deviation amount of a vehicle.

FIG. 6 is a diagram illustrating a positional relationship between a detection range of a sensor and a magnetic marker.

FIG. 7 is a diagram showing the output of each sensor as the vehicle travels.

FIG. 8 is a distance detection map showing a relationship between a magnetic flux density in a vertical direction and a horizontal direction and a lateral distance of a magnetic marker.

FIG. 9 is an explanatory diagram of a detection state of magnetism.

FIG. 10 is a diagram showing a relationship between a magnetic flux density, a lateral distance of a sensor, and a mounting height of the sensor.

FIG. 11 is a diagram illustrating sensitivity and output characteristics of a sensor.

FIG. 12 is a diagram for explaining deviation correction.

FIG. 13 is a flowchart showing a second embodiment.

FIG. 14 is a diagram showing an outline of a conventional example.

[Description of Signs] 1, 2, 3, 4, 5, 40 Sensor 6 Input Circuit 7 Sensor Selection Unit 8 Peak Judgment Unit 9 Distance Calculation Unit 10 Lateral Deviation Amount Calculation Unit 11, 22, 33, 44, 55 Sensor Detection range 14 Output unit 20 Sensor case 30, 100 Magnetic marker 200 Vehicle a Horizontal sensor b Vertical sensor A, B, C, D, E Horizontal distance h Vertical distance g, p Magnetic detection axis F Offset voltage M Magnetic marker Body detection position T Distance between magnetic markers Da, Db Differential amplifier α Lines showing lateral deviation detection characteristics.

Claims (4)

[Claims] 1. A magnetic field marker buried on a road surface along a traveling lane, a vertical sensor disposed on a vehicle and detecting a magnetic field in a direction perpendicular to the road surface, and a vertical sensor disposed on the vehicle and disposed in a horizontal and horizontal direction of the vehicle. A travel position sensor having a horizontal sensor for detecting a magnetic field, and determining a lateral deviation of the vehicle with respect to the magnetic marker by an operation based on a correlation between an output signal of the vertical sensor and an output signal of the horizontal sensor. A plurality of vertical sensors and the horizontal sensors are arranged at predetermined intervals in the width direction of the vehicle as a sensor pair, and a sensor pair 1 and a sensor pair 2 closest to the magnetic field marker with the magnetic marker interposed therebetween. A predetermined calculation formula is used based on a lateral deviation calculation value of the vehicle calculated from the output signal and a lateral deviation value of the vehicle when the magnetic field marker is located immediately below the sensor pair 1 and the sensor pair 2. Calculate the lateral deviation of the vehicle A traveling position sensor characterized by: 2. The predetermined arithmetic expression is such that the lateral deviation values of the vehicle when the magnetic marker is located immediately below the sensor pair 1 and the sensor pair 2 are A1 and B1, respectively, and the sensor pair 1 and the sensor pair When the magnetic marker is positioned between the two, the lateral deviation values of the vehicle obtained based on the output signals of the sensor pair 1 and the sensor pair 2 are A2 and B2, respectively, and the calculation result of the predetermined calculation expression is Assuming that the lateral deviation value of a certain vehicle is Y, Y = A1 + (A2-A1) / [[(B2-B1) + (A
2-A1)] · (B2-A1)] The travel position sensor according to claim 1, wherein the travel position sensor is represented by the following mathematical formula. 3. The predetermined arithmetic expression is such that the lateral displacement values of the vehicle when the magnetic marker is located immediately below the sensor pair 1 and the sensor pair 2 are A1 and B1, respectively, and the sensor pair 1 and the sensor pair When the magnetic marker is positioned between the two, the lateral deviation values of the vehicle obtained based on the output signals of the sensor pair 1 and the sensor pair 2 are A2 and B2, respectively, and the calculation result of the predetermined calculation expression is The lateral displacement value of a certain vehicle is represented by Y, wherein Y = A1 + β · B2 + (1-β) · A2β = (A2-A1) / (B2-A1). Travel position sensor according to any of the preceding claims. 4. The vehicle according to claim 1, wherein the magnetic markers are arranged with different magnetic polarities, and the lateral deviation of the vehicle is detected only at a predetermined location based on the polarity information of the magnetic markers. Item 3. The travel position sensor according to item 1, 2 or 3.