Vehicle system and vehicle control method

Abstract

In a vehicle system (1), a plurality of magnetic sources (1), in which a direction in which N-poles and S-poles face each other coincides with a travel path (10) direction, form a row along the travel path (10) and are arranged so that gaps (1G) are formed between adjacent magnetic sources (1) along the travel path (10) direction. The length of the gaps (1G) is set so that at least a magnetic component orthogonal to the travel direction acts on a vehicle even in the gaps (1G). The controllability of a vehicle using the magnetic sources (1) is thus favorable.

Description

Vehicle system and vehicle control method

[0001] The present invention relates to a vehicle system including a magnetic source laid on a road of the vehicle, and a vehicle control method that utilizes the magnetic source laid on the road.

[0002] Conventionally, magnetic markers laid on roads have been known as magnetic sources that can be detected while a vehicle is traveling (see, for example, Patent Document 1). Magnetic sources such as magnetic markers are placed at intervals along a lane, for example. A vehicle that can detect magnetic markers can estimate the relative position of the vehicle using the detected magnetic marker as a reference. For example, by using magnetic markers laid along a lane as a reference, the lateral deviation of a vehicle within the lane can be measured. If the lateral deviation of a vehicle within the lane can be determined, various driving assistance controls such as automatic steering control, lane departure warning, and automatic driving can be realized.

[0003] Japanese Patent Application Laid-Open No. 2005-202478

[0004] However, the conventional magnetic markers have the following problem: when a magnetic marker is detected, the lateral deviation of the vehicle relative to the magnetic marker can be measured and steering control based on the lateral deviation is possible, but after detecting a magnetic marker, it is difficult to estimate the lateral deviation of the vehicle in the lane until a new magnetic marker is detected.

[0005] The present invention has been made in consideration of the above-mentioned problems of the conventional art, and aims to provide a vehicle system including a magnetic source laid on a roadway, which is useful for improving the controllability of the vehicle, and a vehicle control method that utilizes this vehicle system.

[0006] One aspect of the present invention is a vehicle system including a plurality of magnetic sources laid along a roadway, each of the plurality of magnetic sources having a pair of opposing north and south poles, and laid so that the direction in which the north and south poles face each other coincides with the direction of the roadway, the plurality of magnetic sources are laid so as to form a row with magnetic poles of the same polarity facing each other across a gap between two adjacent magnetic sources, and the length of the gap is set so that at least a magnetic component perpendicular to the direction of travel acts on the vehicle in the gap.

[0007] One aspect of the present invention is a control method for controlling vehicle travel or assisting vehicle operation along a roadway on which a plurality of magnetic sources are installed, wherein each of the plurality of magnetic sources has a pair of opposing north and south poles, and is installed so that the direction in which the north and south poles face each other coincides with the direction of the roadway, the plurality of magnetic sources are installed so that two adjacent magnetic sources are arranged in a row with magnetic poles of the same polarity facing each other across a gap, and the length of the gap is set so that at least a magnetic component perpendicular to the direction of travel acts on the vehicle in the gap, and the vehicle travel or operation is controlled so that the magnetic field from the plurality of magnetic sources is maintained.

[0008] The magnetic source in the present invention is a pair of magnetic sources each having a combination of opposing north and south poles. Each magnetic source is installed so that the direction in which the north and south poles face each other coincides with the direction of the track.

[0009] In the present invention, a plurality of magnetic sources are arranged in a row with magnetic poles of the same polarity facing each other across a gap between two adjacent magnetic sources, and the length of the gap between the two adjacent magnetic sources is set so that at least the magnetic component perpendicular to the direction of travel acts on the vehicle through the gap.

[0010] A control method constituting one aspect of the present invention is a method for controlling a vehicle or performing control to assist driving of the vehicle so as to maintain a state in which magnetic fields from at least one of a plurality of magnetic generating sources are acting.

[0011] The vehicle system according to one aspect of the present invention is a useful system that can apply magnetic force to the vehicle even in the gap between two adjacent magnetic markers, thereby achieving reliable control. According to the vehicle control method according to one aspect of the present invention, the magnetic force of the magnetic source can be used even in the gap between two adjacent magnetic markers, thereby improving the reliability of control.

[0012] 1 is a perspective view of a magnetic marker in Example 1. FIG. 2 is an explanatory diagram of a track on which magnetic markers are laid in Example 1. FIG. 3 is an explanatory diagram showing the embedded state of magnetic markers in Example 1. FIG. 4 is an explanatory diagram of a vehicle traveling on a track in Example 1. FIG. 5 is a configuration diagram of a sensor unit in Example 1. FIG. 6 is a graph illustrating an example of a change in a magnetic measurement value Gv while traveling on a track in Example 1. FIG. 7 is a graph illustrating an example of a change in a magnetic measurement value Gt while traveling on a track in Example 1. FIG. 8 is a graph illustrating a change in the sum of squares Ssq of the magnetic measurement values ​​Gv and Gt in the traveling direction in Example 1. FIG. 9 is a graph illustrating the distribution of the sum of squares Ssq of the magnetic measurement values ​​Gv and Gt in the vehicle width direction in Example 1. FIG. 10 is an explanatory diagram showing a continuous (rail-shaped) member provided with a plurality of magnetic generating sources in Example 1. FIG. 11 is a graph illustrating the distribution of MSsq in the vehicle width direction, which is the sum of squares Ssq of the magnetic measurement values ​​Gv and Gt with the positive and negative reversed in Example 2. 17 is an explanatory diagram of a virtual magnetic groove along a track in Example 2. FIG. 18 is a configuration diagram of a sensor unit in Example 2. FIG. 19 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2. FIG. 20 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2. FIG. 21 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2. FIG. 22 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2. FIG. 23 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2. FIG. 24 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2. FIG. 25 is an explanatory diagram showing how the vehicle is guided by the virtual magnetic groove in Example 2.

[0013] The present invention will be described in detail below with reference to the following examples. (Example 1) This example relates to a vehicle system 1S including a plurality of magnetic markers 1 laid on a track 10. The details of this example will be described with reference to FIGS. 1 to 10.

[0014] Magnetic marker 1 is an example of a magnetic source. As shown in Figure 1, magnetic marker 1 in this example is a rod-shaped magnetic marker consisting of a single magnet. In magnetic marker 1, the north pole and south pole face each other in the longitudinal direction. The magnet that makes up magnetic marker 1 is a round bar magnet with a diameter of 20 mm and a length of 500 mm. Magnetic marker 1 may be the magnet itself, a magnet with a coating material applied to its outer surface, or a magnet housed in a resin case.

[0015] The magnet that makes up the magnetic marker 1 has different magnetic poles at both ends in the longitudinal direction. This magnet is a ferrite plastic magnet in which iron oxide magnetic powder, a magnetic material, is dispersed in a polymeric base material, and has a maximum energy product (BHmax) of 6.4 kJ / cubic meter.

[0016] In the vehicle system 1S, multiple magnetic markers 1 are laid in a row along an arrangement line 1L that runs along the track 10 ( FIG. 2 ). A gap 1G is provided between adjacent magnetic markers 1. The length of this gap 1G is 100 mm. The longitudinal direction of each magnetic marker 1, in which the north and south poles face each other, coincides with the direction of the track 10. Furthermore, each magnetic marker 1 is laid so that the magnetic pole of the same polarity as that of an adjacent magnetic marker 1 faces across the gap 1G. In the vehicle system 1S, the direction from the north pole to the south pole of each magnetic marker 1 alternates along the track 10. Note that in each figure, including FIG. 2 , in which the magnetic marker 1 is shown together with the vehicle 2 or the track 10, the magnetic marker 1 is illustrated larger than it actually is.

[0017] The magnetic marker 1 is laid buried in the track 10, as shown in Figure 3. The cross-sectional structure of the road that forms the track 10 will now be described. The cross-sectional structure of a road paved with asphalt or the like roughly has a three-layer structure consisting of a roadbed 10C made of compacted soil, a roadbase 10B made of granular material such as crushed stone or crushed run, and a surface layer 10A made of a heated asphalt mixture. The thickness of the surface layer 10A is approximately 50 mm, and the thickness of the roadbase 10B is approximately 100 mm. The surface layer 10A is layered on top of the lower layer, the roadbase 10B.

[0018] The magnetic markers 1 are buried in a storage trench (not shown) provided along the track 10. The storage trench is 100 mm deep. The magnetic markers 1 are laid down in a horizontal position on the bottom surface of the storage trench. The diameter of the magnetic markers 1 is 20 mm. Therefore, the buried magnetic markers 1 are located at a depth of 80 to 100 mm. This depth of 80 to 100 mm is the depth of the roadbed 10B beyond the surface layer 10A, which is approximately 50 mm thick. In the vehicle system 1S of this example, each magnetic marker 1 is buried in the roadbed 10B.

[0019] The vehicle 2 ( FIG. 4 ) using the magnetic marker 1 is, for example, a typical passenger car with a width of 1.8 m and a length of 4.5 m. The vehicle 2 is equipped with operating mechanisms such as a steering wheel, an accelerator, and a brake. The vehicle 2 is equipped with a plurality of actuators (not shown) that drive these operating mechanisms, and a control unit 20 that controls these actuators. The control unit 20 is an example of a control circuit configured to control the driving of the vehicle 2 or to assist the driving of the vehicle 2. The vehicle 2 can be manually driven by a driver, or can be automatically driven under the control of the control unit 20. The vehicle 2 can automatically drive using the magnetic marker 1 laid along the road 10. For example, the control unit 20 controls the steering of the vehicle 2 to suppress lateral deviation from the magnetic marker 1.

[0020] The vehicle 2 is equipped with a sensor unit 3 (Figure 5) for detecting the magnetic marker 1. The sensor unit 3 is an example of a magnetic detection circuit. The sensor unit 3 is a rod-shaped unit in which 15 magnetic sensors C1 to C15 are arranged in a straight line. The 15 magnetic sensors C1 to C15 are spaced at equal intervals of 10 cm. The sensor unit 3 is attached, for example, to the inside of the front bumper of the vehicle 2, with its longitudinal direction aligned with the vehicle width direction. In the case of the vehicle 2 in this example, the attachment height of the sensor unit 3 relative to the road surface 10S is 200 mm. The magnetic sensor C1 is located on the left side of the vehicle 2, and the magnetic sensor C15 is located on the right side of the vehicle 2.

[0021] The sensor unit 3 includes a combination of 15 magnetic sensors Cn (n is an integer between 1 and 15) and a signal processing circuit 30 incorporating a CPU (not shown) (see FIG. 5). The magnetic sensors Cn detect magnetism using the well-known magneto-impedance effect (MI). The MI effect is a magnetic effect in which the impedance of a magnetically sensitive material, such as an amorphous wire, changes sensitively in response to an external magnetic field. Each magnetic sensor Cn incorporates two amorphous wires that are perpendicular to each other. The magnetic sensors Cn detect magnetic components acting along the longitudinal direction of each amorphous wire and output a sensor signal representing the magnitude of the magnetic components (magnetic measurement value).

[0022] In the sensor unit 3, the axial direction (longitudinal direction) of the two amorphous wires is the same for all 15 magnetic sensors Cn. The sensor unit 3 is attached to the vehicle 2 so that the two amorphous wires of each magnetic sensor Cn are aligned along the traveling direction and the vertical direction. The vertical direction is an example of a direction perpendicular to the traveling direction.

[0023] The signal processing circuit 30 (FIG. 5) is a circuit that executes various processes such as marker detection processing for detecting the magnetic marker 1. The signal processing circuit 30 executes various processes by processing the sensor signals of the magnetic sensors Cn. The sensor signals processed by the signal processing circuit 30 are signals that represent a magnetic measurement value Gv that indicates the magnitude of the magnetic component acting along the vertical direction, and a magnetic measurement value Gt that indicates the magnitude of the magnetic component acting along the traveling direction.

[0024] The signal processing circuit 30 is configured to store the magnetic measurement values ​​Gv, Gt obtained by the magnetic sensor Cn over a predetermined time period in the past, and executes various processes using the magnetic measurement values ​​Gv, Gt obtained over the predetermined time period in the past.

[0025] In addition to the marker detection process, the signal processing circuit 30 also performs a process of measuring the lateral deviation with respect to the magnetic marker 1. The signal processing circuit 30 inputs the results of these processes to the control unit 20. The control unit 20 uses the results of the processing by the signal processing circuit 30 to perform vehicle control such as automatic steering control for lane keeping, lane departure warning, and automatic driving.

[0026] Next, we will explain the details of vehicle control for traveling on the track 10 using the magnetic markers 1. The vehicle control in this example is, in other words, control for causing the vehicle 2 to travel along a virtual magnetic rail formed by the magnetic markers 1.

[0027] Each magnetic sensor Cn of the sensor unit 3 repeatedly performs magnetic detection at a frequency of, for example, 3 kHz while the vehicle 2 is traveling. The sum of the magnetic measurement values ​​Gv (magnetic measurement values ​​in the vertical direction) obtained by the 15 magnetic sensors Cn changes in the direction of travel (direction of the road) as shown in Figure 6. In this figure, the magnetic field acting from the north pole is considered positive, and the magnetic field acting from the south pole is considered negative.

[0028] 6, the magnetic measurement value Gv (sum) reaches a positive peak at the gap 1G (N) where the north poles of two adjacent magnetic markers face each other, and reaches a negative peak at the gap 1G (S) where the south poles face each other. A zero cross occurs at the midpoint 1M (the center position in the longitudinal direction) of each magnetic marker 1, where the positive and negative signs of the magnetic measurement value Gv (sum) are reversed.

[0029] The sum of the magnetic measurement values ​​Gt (magnetic measurement values ​​in the direction of travel) obtained by the 15 magnetic sensors Cn changes in the direction of travel (direction of the track) as shown in Figure 7. In this figure, the magnetic field directed from the north pole to the south pole is considered positive, and the magnetic field directed from the south pole to the north pole is considered negative. The magnetic measurement value Gt (sum) has a positive or negative peak at the midpoint 1M of each magnetic marker 1. Positive and negative peaks appear alternately for each magnetic marker 1 arranged along the track 10. A zero cross where the magnetic measurement value Gt (sum) switches from negative to positive occurs in the gap 1G(N) where the north poles of two adjacent magnetic markers 1 face each other. Furthermore, a zero cross where the magnetic measurement value Gt (sum) switches from positive to negative occurs in the gap 1G(S) where the south poles of two adjacent magnetic markers 1 face each other.

[0030] In the track 10 of this example, the gap 1G between adjacent magnetic markers 1 is set narrow so that a magnetism sufficient for marker detection processing acts on the sensor unit 3. As a result, there is no section in the direction of travel where both the magnetic measurement value Gt (sum) and the magnetic measurement value Gv (sum) are zero. In particular, when the gap 1G is set sufficiently narrow as in this example, the changes in the magnetic measurement value Gt (sum) and the magnetic measurement value Gv (sum) in the direction of travel become smooth changes like trigonometric functions.

[0031] 6 and 7, the change in the magnetic measurement value Gt in the traveling direction and the change in the magnetic measurement value Gv in the traveling direction have the same period, but are out of phase with each other by a quarter period. The relationship between the change in the magnetic measurement value Gt in the traveling direction and the change in the magnetic measurement value Gv in the traveling direction is similar to, for example, the relationship between a sine function and a cosine function. Similar to the fact that the sum of the squares of the sine value and the cosine value is 1, the sum of the squares Ssq of the magnetic measurement values ​​Gv (sum) and Gt (sum) is a nearly constant value in the traveling direction (FIG. 8).

[0032] On the other hand, the sum of squares Ssq of the magnetic measurement values ​​Gv and Gt of each magnetic sensor Cn is distributed in the vehicle width direction as shown in Figure 9. This figure shows the distribution of the sum of squares Ssq of each magnetic sensor Cn using an approximate curve. The left side of the figure corresponds to the left side of the vehicle 2, and the right side of the figure corresponds to the right side of the vehicle 2.

[0033] The vehicle width direction distribution of the sum of squares Ssq of each magnetic sensor Cn in Figure 9 reaches a peak at the position of the magnetic marker 1 in the vehicle width direction. The position of the peak in the vehicle width direction represents the lateral deviation of the vehicle 2 relative to the magnetic marker 1. For example, if the vehicle 2 deviates to the right relative to the magnetic marker 1, the position of the peak in the vehicle width direction will be shifted to the left in the figure. For example, if the vehicle 2 deviates to the left relative to the magnetic marker 1, the position of the peak in the vehicle width direction will be shifted to the right in the figure. In this way, by identifying the position of the peak in the vehicle width direction, it is possible to measure the lateral deviation of the vehicle 2 relative to the magnetic marker 1.

[0034] The control unit 20 constantly acquires the lateral deviation measured by the sensor unit 3. The control unit 20 controls the steering angle (of the steered wheels) so that the lateral deviation approaches a predetermined value such as zero. By such steering control, the traveling of the vehicle 2 can be controlled so that the magnetism of the magnetic marker 1 is maintained in a state where it acts on the vehicle 2.

[0035] In the vehicle system 1S of this example configured as described above, each magnetic marker 1 is installed so that the direction in which the north and south poles face each other coincides with the direction of the track 10. In this vehicle system 1S, multiple magnetic markers 1 are installed so that they form a row with magnetic poles of the same polarity facing each other with a gap 1G between two adjacent magnetic markers 1.

[0036] In particular, in the vehicle system 1S, the length of the gap 1G between two adjacent magnetic markers 1 is set so that at least the magnetic component perpendicular to the direction of travel acts on the vehicle 2 and can be detected by the sensor unit 3. The vehicle system 1S of this example can control the vehicle 2 so that the magnetic field from the magnetic marker 1 is maintained. According to the control method of this example, the vehicle 2 can be guided continuously by the magnetic field from the magnetic marker 1, enabling highly reliable vehicle control.

[0037] Here, road repairs will be described. When a road is in operation for a long period of time, defects such as potholes may occur on the road surface 10S. A pothole is a hole that occurs when a portion of the surface layer 10A (FIG. 3) made of a heated asphalt mixture peels off from the road surface 10S. Potholes can be repaired, for example, by repaving the road surface 10S. Repaving is a repair that involves removing the deteriorated surface layer 10A to expose the roadbed 10B and laying a new surface layer 10A. By laying a new surface layer 10A through repaving, a defect-free road surface 10S can be restored. As described above, the magnetic marker 1 in this example is embedded in the roadbed 10B. Therefore, the magnetic marker 1 in this example is not dug up during repaving and does not need to be reapplied every time repaving is performed. The magnetic marker 1 can be used for a long period of time.

[0038] In this example, a magnetic marker 1 having a length of 500 mm is illustrated. The length of the magnetic marker 1 may be in the range of 100 to 500 mm, including the 500 mm length in this example. If the length of the magnetic marker 1 is less than 100 mm, the magnetic field loop formed between the north and south poles at both ends becomes small. A smaller magnetic field loop may result in a problem in which the magnetism acting at higher positions becomes weaker, making detection by a magnetic sensor attached to the underside of the vehicle difficult. On the other hand, if the length of the magnetic marker 1 exceeds 500 mm, the magnetic field loop formed between the north and south poles at both ends becomes excessively large, resulting in a low magnetic flux density at a low position near the center of the magnetic marker (around the midpoint between the north and south poles). If the magnetic sensor is attached at a relatively low position, it may become difficult to detect characteristic magnetic changes, such as the change in the magnetic measurement value Gv illustrated in FIG. 6 or the change in the magnetic measurement value Gt illustrated in FIG. 7. The magnetic marker 1 has a north pole and a south pole at both ends, so the length of the magnetic marker 1 is the distance between the north pole and the south pole at the magnetic source.

[0039] In this example, the gap 1G between adjacent magnetic markers 1 is illustrated as a gap with a length of 100 mm in the direction of travel. Gap 1G should be between 0 and 500 mm long. If gap 1G exceeds 500 mm, which is greater than the length of the magnetic marker, there is a risk that magnetic interference with adjacent magnetic markers will be difficult to occur. In this case, each magnetic marker will be close to being magnetically isolated, and the technical effect of laying multiple magnetic markers in a row may be lost. Note that the length of gap 1G is related to the length of magnetic marker 1. The longer the magnetic marker 1, the longer gap 1G can be. Gap 1G should be shorter than the length of a magnetic marker with a north pole and a south pole at both ends. If gap 1G is longer than the magnetic marker, there is a risk that the degree of magnetic interference with adjacent magnetic markers will be insufficient.

[0040] In this example, the magnetic marker 1 is buried to a depth of 100 mm. The magnetic marker 1 may be buried to a depth of 0 to 500 mm. If the burial depth exceeds 500 mm, the magnetic flux density on the surface side (ground) of the road may become small, making detection by a magnetic sensor difficult.

[0041] In this example, magnetic markers 1 made of round bar magnets are used as the magnetic source, and are laid in a row along the track 10. Instead of the magnetic marker 1 made of round bar magnets, magnetic markers made of magnets with polygonal cross sections may be used. Instead of the magnetic marker 1 made of rod-shaped magnets, magnetic markers made of strip-shaped (tape-shaped) magnets may be used. The strip-shaped magnets may be magnets with north and south poles on both ends.

[0042] This example is a configuration example in which magnetic markers 1, each 500 mm long, are arranged in a line along the track 10. Alternatively, a continuous (rail-shaped) member 100 (FIG. 10) in which magnetic powder is dispersed in a polymeric material may be used. This continuous member 100 is an example of a continuous member or member that is continuous without any breaks in the direction of the track 10.

[0043] By magnetizing the continuous member 100 from the outside, it is possible to provide a magnetic source 11 consisting of a magnetic pole pair of an N pole and an S pole. A plurality of such magnetic sources 11 can be provided in the longitudinal direction with a gap 1G therebetween. Adjacent magnetic sources 11 can be magnetized so that their N poles or S poles face each other with a gap 1G therebetween.

[0044] By laying such a continuous member 100 ( FIG. 10 ) on the track 10, multiple magnetic sources 11 can be laid on the track 10 all at once. In this case, the polymer material is preferably an elastic material having elasticity. An elastic material can deform to fit the curvature of the track 10. The magnetic sources 11 may be provided by magnetizing the member before laying on the track 10, or by magnetizing the member after laying on the track 10. The continuous member 100 may be buried in the road surface 10S or laid on the road surface 10S. The continuous member 100 laid on the road surface 10S may be rod-shaped, such as a flexible curved ruler, or may be strip-shaped (tape-shaped).

[0045] The continuous member without any breaks in the direction of the track 10 may be a plurality of magnets held in a row by a non-magnetic material with elasticity. In this case, the magnets should preferably be elastic, such as ferrite rubber magnets.

[0046] The sensor unit 3 of this example can detect both a magnetic component acting along the direction of travel and a magnetic component acting along the vertical direction. The sensor unit may also be capable of detecting magnetic components including a magnetic component acting along the direction of travel and a magnetic component acting in the vertical direction. A magnetic sensor equipped with a magnetic sensor that is oblique to both the direction of travel and the vertical direction can detect a composite component of the magnetic component acting along the direction of travel and the magnetic component acting in the vertical direction. If the orientation of the magnetic sensor is known, the magnetic component acting along the direction of travel and the magnetic component acting in the vertical direction can be identified based on this composite component. Preferably, the angle of obliqueness relative to the direction of travel and the angle of obliqueness relative to the vertical direction are set to be approximately the same.

[0047] Furthermore, instead of a combination of the traveling direction and the vertical direction, the sensor unit may be capable of detecting a magnetic component acting along the traveling direction and a magnetic component acting along the vehicle width direction (lateral direction).The sensor unit may be capable of detecting a magnetic component acting along the traveling direction, a magnetic component acting along the vertical direction, and a magnetic component acting along the vehicle width direction.

[0048] If the rod-shaped magnetic markers 1 are laid along an arrangement line 1L (FIG. 2), which is an example of such a row, so as to form a row with a narrow gap 1G between them, the distribution waveform of the square sum Ssq of the magnetic measurement values ​​Gv, Gt of each magnetic sensor Cn shown in FIG. 9 will be formed continuously along the road 10. In this case, the peak of the square sum Ssq in the vehicle width direction can be identified regardless of whether the sensor unit 3 is located directly above one of the magnetic markers 1 (magnetic source) or in the gap 1G between adjacent magnetic markers 1.

[0049] Being able to identify the peak of the sum of squares Ssq, regardless of whether the vehicle 2 is located directly above any of the magnetic markers 1 (magnetic sources) or in the gap 1G, means that the lateral deviation of the vehicle 2 with respect to the arrangement line 1L can be measured. If the lateral deviation of the vehicle 2 with respect to the arrangement line 1L can be obtained, the control unit 20 can control the steering angle (of the steering wheels) so as to bring the lateral deviation closer to a predetermined value such as zero, regardless of whether the vehicle 2 is located directly above any of the magnetic markers 1 or in the gap 1G between adjacent magnetic markers 1. With this type of steering control, there is no gap in the control while the vehicle 2 is traveling on the roadway 10, thereby realizing smooth and highly accurate steering control.

[0050] (Embodiment 2) In this embodiment, the configuration of the sensor unit, which is an example of a magnetic detection circuit, and the method of vehicle control are changed based on the vehicle system of embodiment 1. The contents of this embodiment will be described with reference to Figs.

[0051] First, the control method of this embodiment will be outlined with reference to FIGS. 11 and 12. FIG. 11 is a graph of MSsq, which is the sum of squares Ssq of the magnetic measurement values ​​Gv and Gt, with the sign reversed. The horizontal axis in the graph represents the position in the vehicle width direction. The right side in the graph corresponds to the right side as viewed in the direction of the road 10, and the left side in the graph corresponds to the left side as viewed in the direction of the road 10. The graph in FIG. 11 corresponds to the graph in FIG. 9 referred to in the first embodiment, with the sign reversed.

[0052] In this example, on the track 10 where rod-shaped magnetic markers 1 are laid in a row with narrow gaps 1G between them, a continuous MSsq distribution waveform as shown in Figure 11 is formed. The distribution waveform in the figure can be said to represent the cross-sectional shape of a virtual magnetic groove 10T (Figure 12) extending along the track 10. The control method of this example is a method of controlling the vehicle 2 so that it travels along the virtual magnetic groove 10T. In this control method, the sensor unit 3A functions as a guide member, so to speak, to cause the vehicle 2 to travel along the virtual magnetic groove 10T.

[0053] The sensor unit 3A (FIG. 13) of this example includes two magnetic sensors Ca and Cb spaced apart in the vehicle width direction, and a signal processing circuit 30. The magnetic sensors Ca and Cb are spaced apart by 20 cm. The magnetic sensors Ca and Cb have the same specifications as the magnetic sensor Cn of Example 1. Both the magnetic sensors Ca and Cb measure a magnetic measurement value Gv in the vertical direction and a magnetic measurement value Gt in the traveling direction.

[0054] The signal processing circuit 30 acquires magnetic measurement values ​​Gv and Gt from the magnetic sensors Ca and Cb, respectively, and calculates the sums of squares Ssq(a) and Ssq(b) of the magnetic measurement values ​​Gv and Gt. Ssq(a) is the sum of squares of the magnetic sensor Ca. Ssq(b) is the sum of squares of the magnetic sensor Cb. The signal processing circuit 30 calculates the difference D between the sums of squares Ssq(a) and Ssq(b) of the magnetic measurement values ​​Gv and Gt. The difference D is used by the control unit 20 to calculate the control amount (steering angle) of the steered wheels.

[0055] When the neutral steering angle of the steering wheel is used as a reference, steering to the right is defined as a positive side, and steering to the left is defined as a negative side, the control unit 20 steers the steering wheel to the positive side when the difference D is positive, and steers the steering wheel to the negative side when the difference D is negative. Note that the control unit 20 increases the steering amount depending on the magnitude of the difference D.

[0056] The details of such vehicle control will be explained with reference to Figures 14 to 16. These figures explain the details of the control using the MSsq graph shown in Figure 11. Note that the graphs in Figures 14 to 16 are normalized by setting the peak (minimum value) of MSsq in the vehicle width direction to minus 1. As mentioned above, each graph in these figures represents the cross-sectional shape of the imaginary magnetic groove 10T shown in Figure 12.

[0057] The vehicle control of this example will be described by assuming that the inverted value of the sum of squares Ssq(a) associated with magnetic sensor Ca is MSsq(a), and the inverted value of the sum of squares Ssq(b) associated with magnetic sensor Cb is MSsq(b). For example, in the case of FIG. 14, where sensor unit 3A is offset to the left of the magnetic marker 1, sensor unit 3A is positioned on the left slope of the imaginary magnetic groove 10T. In the same figure, MSsq(a) is minus 0.3, and MSsq(b) is minus 0.6. The difference D is (MSsq(a) - MSsq(b)) = 0.3. In this case, since the difference D is a positive value, the steering wheel is steered to the positive side, thereby allowing the vehicle 2 to move closer to the right magnetic marker 1. As mentioned above, MSsq is the inverted value of Ssq. Therefore, the difference D can be transformed as follows: D = MSsq(a) - MSsq(b) = (-1) x Ssq(b) - (-1) x Ssq(a) = Ssq(b) - Ssq(a).

[0058] For example, in the case of Figure 15, where the sensor unit 3A is located to the right of the magnetic marker 1, the sensor unit 3A is located on the right slope of the imaginary magnetic groove 10T. In the case of the figure, MSsq(a) is minus 0.7, and MSsq(b) is minus 0.4. The difference D is (MSsq(a) - MSsq(b)) = minus 0.3. In this case, since the difference D is a negative value, the steering wheel is steered to the negative side, which allows the vehicle 2 to move closer to the magnetic marker 1 on the left side.

[0059] For example, in the case of Figure 16, where the sensor unit 3A is located near directly above the magnetic marker 1, the sensor unit 3A is located near the bottom of the imaginary magnetic groove 10T. In the case of the figure, MSsq(a) is minus 0.90 and MSsq(b) is minus 0.92. The difference D is (MSsq(a) - MSsq(b)) = 0.02, which is close to zero. In the case of the figure, the difference D is a positive value close to zero. In this case, the steering amount of the steering wheel becomes small, and the sensor unit 3A is maintained in a state where it is located near the bottom of the imaginary magnetic groove 10T.

[0060] In the configuration of this example, the sensor unit 3A functions as if it were a guide member that guides the vehicle 2. This guide member is guided by a slope that forms an imaginary magnetic groove 10T ( FIG. 12 ) along the direction of the track 10 so as not to protrude from the magnetic groove 10T. When the sensor unit 3A is positioned on the slope of the magnetic groove 10T, the sensor unit 3A is biased downward on the slope.

[0061] For example, when the sensor unit 3A is located on a slope that slopes downward to the right as shown in FIG. 14, the sensor unit 3A is biased to the right. For example, when the sensor unit 3A is located on a slope that slopes downward to the left as shown in FIG. 15, the sensor unit 3A is biased to the left. For example, when the sensor unit 3A is located near the bottom of the magnetic groove 10T as shown in FIG. 16, the force biasing the sensor unit 3A to the left or right is weak. In this case, the sensor unit 3A is maintained in a state where it is located near the bottom of the magnetic groove 10T. Thus, according to the configuration of this example, the running of the vehicle can be controlled so that the magnetic fields of the multiple magnetic markers 1 are maintained in effect.

[0062] Note that instead of the sensor unit 3A of this example, a sensor unit (reference numeral 3 in FIG. 5) in which multiple magnetic sensors of Example 1 are arranged in the vehicle width direction may be employed. The distribution of Msq in the vehicle width direction may be determined by inverting the sign of the sum of squares Ssq of the magnetic measurement values ​​Gv and Gt obtained by each magnetic sensor, and an approximate curve such as that shown in FIG. 11 may be calculated. As described above, on the track 10 of this example, where the rod-shaped magnetic markers 1 are laid in a row with a narrow gap 1G between them, a continuous distribution waveform of MSsq as shown in FIG. 11 is formed, and a virtual magnetic groove 10T shown in FIG. 12 is formed extending along the track 10.

[0063] Therefore, as shown in Fig. 17, it is also possible to assume a representative point 2P as a virtual point representing the vehicle 2, such as the position of the magnetic sensor in the center of the sensor unit 3, and employ control so that this representative point 2P does not protrude from the groove 10T. Note that the graph curve in Fig. 17 is an approximation curve of Msq, and the control content of the control unit 20 will be explained using as examples the case where the representative point 2P is located in region E1 in the figure (Fig. 18) and the case where the representative point 2P is located in region E2 (Fig. 19), which are curves forming the cross section of the groove 10T.

[0064] The control unit 20 assumes gravity G at the representative point 2P as shown in Figures 18 and 19. The control unit 20 executes a calculation to resolve gravity G into a component C1 or C2 along the slope and a component normal to the slope, depending on the gradient of the slope of the groove 10T (see Figure 12), i.e., the gradient of the approximate curve of Msq in Figure 17. The control unit 20 then determines the steering amount of the steered wheels of the vehicle 2 depending on the component C1 or C2.

[0065] For example, when the representative point 2P is located on a slope sloping downward to the right as shown in Figure 18, a rightward component C1 resulting from gravity G is generated. The control unit 20 treats this rightward component C1 as a lateral biasing force that biases the vehicle 2 in the lateral direction. The control unit 20 controls the steering wheels of the vehicle 2 in accordance with the magnitude of the lateral biasing force C1.

[0066] For example, when the representative point 2P is located on a slope sloping downward to the left as shown in Figure 19, a leftward component C2 is generated due to gravity G. The control unit 20 treats this leftward component C2 as a lateral biasing force and controls the steering wheels of the vehicle 2 according to the magnitude of the component C2.

[0067] 18 and 19, the slope where the representative point 2P is located is different, either downward to the right or downward to the left, and the inclination of the slope is also different. The slope where the representative point 2P is located is steeper in region E1 in FIG. 18. The magnitudes of the lateral biasing forces C1 and C2 differ between region E1 in FIG. 18 and region E2 in FIG. 19 in accordance with the difference in the inclination of the slope. The lateral biasing force C1 is greater in region E1 where the slope where the representative point 2P is located is steeper, and therefore the control amount to pull the vehicle 2 to the right is greater.

[0068] The other configurations and effects are the same as those of the first embodiment.

[0069] Although specific examples of the present invention have been described in detail as examples, these examples merely disclose examples of the technology encompassed by the claims. Needless to say, the scope of the claims should not be interpreted as being limited by the configurations, numerical values, etc. of the specific examples. The claims encompass technologies that are obtained by variously modifying, changing, or appropriately combining the above specific examples by utilizing publicly known technology and the knowledge of those skilled in the art.

[0070] 1 Magnetic marker (magnetic source) 1G, 1G (N), 1G (S) Gap 1L Array line (single row) 1S Vehicle system 10 Runway 10A Surface 10B Roadbed 10C Roadbed 10S Road surface 10T (virtual) magnetic groove 100 Continuous member 11 Magnetic source 2 Vehicle 20 Control unit (control circuit) 3, 3A Sensor unit (magnetic detection circuit) Cn (n is an integer from 1 to 15), Ca, Cb Magnetic sensor 30 Signal processing circuit

Claims

1. A vehicle system including a plurality of magnetic sources laid along a roadway, each of which has a pair of opposing north and south poles, and which is laid so that the direction in which the north and south poles face each other coincides with the direction of the roadway, and the plurality of magnetic sources are laid in a row with magnetic poles of the same polarity facing each other across a gap between two adjacent magnetic sources, and the length of the gap is set so that at least a magnetic component perpendicular to the direction of travel acts on the vehicle in the gap.

2. A vehicle system according to claim 1, wherein the plurality of magnetic sources are bar- or strip-shaped magnets each having a north pole end and a south pole end.

3. A vehicle system according to claim 1, wherein each of said magnetic generating sources is provided together with other magnetic generating sources on a continuous, unbroken member along the direction of the track.

4. A vehicle system according to claim 3, wherein the continuous member is a rod- or strip-shaped member in which magnetic powder is dispersed in a polymeric material, and each of the magnetic sources is formed by magnetizing the continuous member to a north pole and a south pole at different positions in the longitudinal direction.

5. A vehicle system according to claim 1, wherein the distance between the north pole and south pole of each of the magnetic sources is 100 to 500 mm, and the length of the gap between two adjacent magnetic sources is 0 to 500 mm.

6. A vehicle system according to any one of claims 1 to 5, wherein the track is a paved road, with a surface layer made of paving material forming the road surface laminated on a lower layer, and each of the magnetic generating sources is disposed beyond the surface layer in the lower layer.

7. A vehicle system according to any one of claims 1 to 6, comprising: a magnetic detection circuit attached to a vehicle so as to be able to detect magnetic fields acting from the plurality of magnetic sources; and a control circuit configured to control the running of the vehicle or assist the driving of the vehicle, wherein the control circuit is configured to control the running of the vehicle or assist the driving of the vehicle so as to maintain a state in which the magnetic field from any one of the plurality of magnetic sources is detected by the magnetic detection circuit.

8. A vehicle system as claimed in claim 7, wherein the magnetic detection circuit acquires magnetic measurement values ​​Gv acting in the vertical direction and magnetic measurement values ​​Gt acting in the direction of travel of the vehicle at multiple locations in the vehicle width direction, determines the distribution of the sum of squares of the magnetic measurement values ​​Gv and Gt in the vehicle width direction, and identifies the maximum value of the distribution of the sum of squares in the vehicle width direction, thereby measuring at least the lateral deviation of the vehicle with respect to each magnetic source among the multiple magnetic sources, and the control circuit uses the lateral deviation to control the running of the vehicle or assist the driving of the vehicle.

9. A vehicle system as claimed in claim 8, wherein the magnetic detection circuit is capable of measuring the lateral deviation of the vehicle relative to a line in which the plurality of magnetic sources are laid out, regardless of whether the magnetic detection circuit is located directly above each magnetic source or in the gap between two adjacent magnetic sources, and the control circuit is capable of using the lateral deviation of the vehicle relative to the line measured by the magnetic detection circuit in the gap between the two adjacent magnetic sources to control the running of the vehicle or assist the driving of the vehicle.

10. A vehicle system as claimed in claim 7, wherein the magnetic detection circuit acquires, at at least two locations in the vehicle width direction, a magnetic measurement value Gv acting in the vertical direction and a magnetic measurement value Gt acting in the direction of travel of the vehicle, and determines the sum of the squares of the magnetic measurement values ​​Gv and Gt; and the control circuit calculates a control amount for the steering wheels of the vehicle according to the magnitude of the difference between the square sums at the at least two locations, and uses the control amount to control the running of the vehicle or assist the driving of the vehicle.

11. A vehicle system as claimed in claim 7, wherein the magnetic detection circuit is configured to acquire magnetic measurement values ​​Gv acting in the vertical direction and magnetic measurement values ​​Gt acting in the direction of travel of the vehicle at multiple locations in the vehicle width direction, and to calculate the sum of squares of the magnetic measurement values ​​Gv and Gt, and the control circuit controls the running of the vehicle or assists the driving of the vehicle so that a virtual point representing the vehicle does not protrude from a virtual groove formed by extending a curve obtained by inverting the positive and negative of an approximation curve of the distribution of the square sums in the vehicle width direction in the direction of the road.

12. A control method for controlling the running of a vehicle or assisting the driving of a vehicle along a road on which a plurality of magnetic sources are installed, wherein each of the plurality of magnetic sources has a pair of opposing north and south poles, and is installed so that the direction in which the north and south poles face each other coincides with the direction of the road, and the plurality of magnetic sources are installed so that two adjacent magnetic sources are arranged in a row with magnetic poles of the same polarity facing each other through a gap, and the length of the gap is set so that at least a magnetic component perpendicular to the direction of travel acts on the vehicle in the gap, and the method controls the running of the vehicle or controls the driving of the vehicle so as to maintain the state in which the magnetic fields from the plurality of magnetic sources are acting.

13. A vehicle control method as claimed in claim 12, wherein a magnetic detection circuit is attached to the vehicle, which acquires, at a plurality of locations in the vehicle width direction, magnetic measurement values ​​Gv acting in the vertical direction and magnetic measurement values ​​Gt acting in the vehicle's traveling direction; the sum of squares of the magnetic measurement values ​​Gv and Gt at the plurality of locations in the vehicle width direction is calculated to determine the distribution of the sum of squares in the vehicle width direction; and by identifying the maximum value of the distribution of the sum of squares in the vehicle width direction, the lateral deviation of the vehicle with respect to a line in which the plurality of magnetic generating sources are laid out is identified, regardless of whether the plurality of locations are located directly above each of the magnetic generating sources or whether the plurality of locations are located in a gap between two adjacent magnetic generating sources; and the lateral deviation of the vehicle with respect to the line in both cases where the plurality of locations are located directly above each of the magnetic generating sources and where the plurality of locations are located in a gap between two adjacent magnetic generating sources is used to control the running of the vehicle or assist the driving of the vehicle.

14. A vehicle control method as claimed in claim 12, wherein a magnetic detection circuit is attached to the vehicle at least at two locations in the vehicle width direction to acquire a magnetic measurement value Gv acting in the vertical direction and a magnetic measurement value Gt acting in the vehicle's traveling direction, the method calculates the sum of squares of the magnetic measurement value Gv and the magnetic measurement value Gt at the at least two locations in the vehicle width direction, calculates a control amount for the steering wheels of the vehicle according to the magnitude of the difference between the sums of squares at the at least two locations, and uses the control amount to control the vehicle's traveling or assist the driving of the vehicle.

15. A vehicle control method as claimed in claim 12, wherein a magnetic detection circuit is attached to the vehicle to acquire, at a plurality of locations in the vehicle width direction, magnetic measurement values ​​Gv acting in the vertical direction and magnetic measurement values ​​Gt acting in the vehicle's traveling direction; the method calculates the sum of squares of the magnetic measurement values ​​Gv and the magnetic measurement values ​​Gt at the plurality of locations in the vehicle width direction; imagines a virtual groove formed by a curve obtained by inverting the positive and negative of an approximation curve of the distribution of the sum of squares in the vehicle width direction, extending in the direction of the road; and controls the running of the vehicle or assists the driving of the vehicle so that a virtual point representing the vehicle does not protrude from the virtual groove.

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