Marker system and control method

Abstract

To provide a marker system helpful in ensuring excellent controllability of a vehicle on a branch path or a merging path.SOLUTION: In a marker system 1 where magnetic markers 10 are arranged along a travel path 100 of a vehicle having a magnetic detection circuit which includes a magnetic detection area long in a vehicle width direction, slave magnetic markers 10A are arranged in a predetermined section S1 preceding a branch point on a main track 110 so that the magnetic detection circuit of the vehicle can detect the magnetic markers concurrently with master magnetic markers 10M arranged on the main track 110.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a marker system in which magnetic markers are arranged on a road so that they can be detected while the vehicle is traveling, and a vehicle control method. [Background technology]

[0002] Marker systems have been known in the past in which magnetic markers are placed along a roadway so that the vehicle can detect them while it is traveling (see, for example, Patent Document 1). This marker system is intended for vehicles equipped with a magnetic sensor unit with a detection area that is long in the vehicle width direction, for example. The vehicle detects the magnetic markers while traveling and measures the lateral deviation from the detected magnetic markers. In the marker system, for example, the steering wheels of the vehicle are controlled so that the lateral deviation from the magnetic marker approaches zero, thereby enabling the vehicle to travel automatically along the roadway. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-199247 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional marker system has the following problem: For example, steering control may become more difficult at junctions or crossroads where marker-laying lines on which magnetic markers are arranged branch off or merge.

[0005] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a marker system and a control method that are useful for ensuring good vehicle controllability on branching roads and merging roads. [Means for solving the problem]

[0006] One aspect of the present invention is a control method for a vehicle equipped with a magnetic detection circuit having a magnetic detection area that is long in the vehicle width direction, to travel while detecting magnetic markers arranged at intervals along a route, the method comprising: The route includes, in addition to a route that forms a main line, at least one of a route that branches off from the route that forms the main line starting from a branch point, and a route that merges with the route that forms the main line at a junction point; In a predetermined section of the route that forms the main line, just before the branch point or just past the junction, secondary magnetic markers are arranged so that the magnetic detection circuit, which has a magnetic detection area that is long in the vehicle width direction, can detect the secondary magnetic markers simultaneously with the primary magnetic markers arranged on the route that forms the main line; at least one of branch control for allowing a vehicle to enter the branching route from the route forming the main line and merging control for allowing a vehicle to merge from the merging route onto the route forming the main line, the branching control is a control that, when simultaneous detection of the primary magnetic marker and the secondary magnetic marker occurs consecutively a predetermined number of times, switches from control that follows the primary magnetic marker to control that follows the secondary magnetic marker, and causes the vehicle to travel by following the magnetic markers arranged along the branching routes after passing the branching point; The merging control is a vehicle control method that, upon passing the merging point, transitions from a control state in which the vehicle travels by following magnetic markers placed along the merging route to a control state in which the vehicle travels along the route that forms the main line by following the secondary magnetic marker, and when simultaneous detection of the primary magnetic marker and the secondary magnetic marker occurs consecutively a predetermined number of times, switches from control that follows the secondary magnetic marker to control that follows the primary magnetic marker.

[0007] One aspect of the present invention is a marker system that places magnetic markers along a route traveled by a vehicle having a magnetic detection circuit with a magnetic detection area that is long in the vehicle width direction, the marker system comprising: The route includes, in addition to a route that forms a main line, at least one of a route that branches off from the route that forms the main line starting from a branch point, and a route that merges with the route that forms the main line at a junction point; The marker system is characterized in that, in a predetermined section of the route that forms the main line, just before the branch point or just past the merging point, secondary magnetic markers are arranged so that the magnetic detection circuit, which has a magnetic detection area that is long in the vehicle width direction, can detect them simultaneously with the primary magnetic marker arranged on the route that forms the main line. [Effects of the Invention]

[0008] In the marker system according to the present invention, secondary magnetic markers are arranged in a predetermined section of a route that forms a main line, either before a branch point or after a junction, so that they can be detected simultaneously with the primary magnetic marker on the main line. The secondary magnetic markers can serve as landmarks for branch points or junction points. Simultaneous detection of the primary and secondary magnetic markers can trigger switching between control that follows the primary magnetic marker and control that follows the secondary magnetic marker.

[0009] The marker system according to the present invention is useful for improving vehicle controllability on diverging or merging routes. A control method using this marker system can reliably execute branching from or merging onto a main lane. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of a marker system according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of a magnetic marker according to the first embodiment. [Figure 3] FIG. 1 is a configuration diagram of a vehicle in a first embodiment. [Figure 4] 10 is a graph of an approximation curve representing the distribution of magnetic measurement values ​​derived from one magnetic marker in the vehicle width direction in the first embodiment. [Figure 5]FIG. 1 is an explanatory diagram of the manner in which magnetic markers are installed at a branch point in the first embodiment. [Figure 6] FIG. 10 is an explanatory diagram of the manner in which magnetic markers are installed at a merging point in the first embodiment. [Figure 7] 10 is a graph of an approximate curve representing the distribution in the vehicle width direction of magnetic measurement values ​​derived from two magnetic markers of the same magnetic polarity arranged side by side in Example 1. [Figure 8] 2 is a second graph of an approximate curve representing the distribution in the vehicle width direction of magnetic measurement values ​​derived from two magnetic markers of the same magnetic polarity arranged side by side in Example 1. [Figure 9] 10 is a graph of an approximation curve showing the distribution in the vehicle direction of magnetic measurement values ​​derived from two magnetic markers of different magnetic polarities arranged side by side in the first embodiment. [Figure 10] 10 is a diagram illustrating the relationship between the distance between two magnetic markers arranged side by side and the combination of magnetic polarities in the first embodiment. FIG. [Figure 11] FIG. 10 is a diagram showing the magnetic polarity of each magnetic marker installed at a branch point in the first embodiment. [Figure 12] FIG. 10 is a diagram showing the magnetic polarity of each magnetic marker installed at a merging point in Example 1. [Figure 13] 1 is a first flowchart showing the flow of vehicle travel control in the first embodiment. [Figure 14] FIG. 10 is a second flowchart showing the flow of vehicle travel control in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The embodiments of the present invention will be specifically described using the following examples. Example 1 This example relates to a marker system 1 in which magnetic markers 10 are arranged along a route, and a method for controlling a vehicle 2. The details of this example will be described with reference to FIGS.

[0012] The marker system 1 (Fig. 1) of this example is, for example, a system of magnetic markers 10 laid on a track 100 for a vehicle 2. The track 100 is, for example, a track that constitutes a BRT (bus rapid transit) system. On the track 100 to which the marker system 1 is applied, the vehicle 2 (bus) travels automatically while detecting the magnetic markers 10. Note that Fig. 1 does not show all of the magnetic markers 10 arranged along the track 100, but omits some of them.

[0013] The track 100 is, for example, a one-way circular track with a width of 3 m. Magnetic markers 10 are laid on the track 100 at intervals in the direction of travel. In this example, the magnetic markers 10 are spaced apart at 2 m intervals. The marker system 1 is used for a vehicle 2 to travel along the circular track 100. The track 100 has a section where a side road 120 is provided for a main track 110. The track 100 that forms the main track 110 and the track 100 that forms the side road 120 are examples of routes on which the vehicle 2 travels. The side road 120 is an example of a route that branches off from the route that forms the main track 110, and an example of a route that merges with the route that forms the main track 110.

[0014] There are two types of driving routes for a vehicle 2 on the road 100 illustrated in FIG. 1. The first driving route is a driving route that travels along the main road 110 without entering the side road 120. The second driving route is a driving route that travels along the main road 110 via the side road 120. A vehicle 2 traveling on the first driving route is controlled to pass directly through a branch point 121 onto the side road 120. A vehicle 2 traveling on the second driving route is controlled to branch off from the branch point 121 onto the side road 120, and then merge onto the main road 110 at a merging point 123.

[0015] The magnetic marker 10 (Figure 2) is a cylindrical magnet with a diameter of 30 mm and a height of 20 mm. One end face of the cylindrical magnetic marker 10 forms a north pole and the other end face forms a south pole. The magnetic marker 10 is buried in a hole drilled in the road surface. It is also possible to use a sheet-type magnetic marker. A sheet-type magnetic marker can be installed by adhering it to the road surface.

[0016] The vehicle 2 (Fig. 3) in this example is a bus vehicle with a length of 8 m and a width of 2.3 m. The vehicle 2 has operating systems such as a steering wheel, accelerator, and brake. The vehicle 2 is equipped with a plurality of actuators (not shown) that drive these operating systems, and a control unit 20 that controls these actuators. The vehicle 2 can be driven manually by a driver, and can also be driven automatically under the control of the control unit 20.

[0017] The vehicle 2 is configured to be capable of autonomous driving using magnetic markers 10 laid along a road 100. The vehicle 2 is equipped with a magnetic sensor module 3 for detecting the magnetic markers 10. The magnetic sensor module 3 is attached to the front of the vehicle 2. The magnetic sensor module 3 executes a process (marker detection process) for detecting the magnetic markers 10 in accordance with control by a control unit 20.

[0018] The magnetic sensor module 3 is an example of a magnetic detection circuit having a magnetic detection area that is long in the vehicle width direction. Although not shown, the magnetic sensor module 3 is configured to include multiple magnetic sensors and a processing circuit that executes arithmetic processing. In the magnetic sensor module 3, multiple magnetic sensors (not shown) are attached at intervals to a rod-shaped frame. The magnetic sensor module 3 is attached to the vehicle 2 so that its longitudinal direction is along the vehicle width direction. The length of the rod-shaped magnetic sensor module 3 is close to the width of the vehicle 2. The magnetic sensor module 3 has a magnetic detection area that is long in the vehicle width direction. The magnetic sensor module 3 can reliably detect the magnetic marker 10 regardless of lateral deviation of the vehicle 2 within the road 100.

[0019] Each magnetic sensor in the magnetic sensor module 3 is built in so that it can measure the magnitude of magnetic fields acting in the vertical direction. When the magnetic sensor module 3 is located directly above the magnetic marker 10, the distribution of magnetic measurement values ​​from the multiple magnetic sensors arranged in the vehicle width direction is, for example, as shown in Figure 4. This figure shows the magnetic measurement values ​​of each magnetic sensor approximated by a curve. The horizontal axis in this figure indicates the vehicle width direction. As shown in this figure, when the magnetic sensor module 3 is located directly above the magnetic marker 10, the distribution of magnetic measurement values ​​from each magnetic sensor becomes a mountain-shaped magnetic distribution with a peak value directly above the magnetic marker 10.

[0020] The processing circuit of the magnetic sensor module 3 applies a marker detection process to the distribution of magnetic measurement values ​​of each magnetic sensor. In the marker detection process, when there is one peak that exceeds a threshold, as in the approximate curve of FIG. 4, for example, it is determined that one magnetic marker 10 has been detected.

[0021] In the marker detection process, in addition to determining whether or not the magnetic marker 10 was detected, the magnetic polarity of the detected magnetic marker 10 is determined, and the lateral deviation of the vehicle 2 relative to the detected magnetic marker is measured. Each magnetic sensor of the magnetic sensor module 3 is configured to output a positive magnetic measurement value in response to the magnetism acting from the magnetic marker 10N with an N pole, and to output a negative magnetic measurement value in response to the magnetic marker 10S with an S pole, as in the example of FIG. 4, for example. In the marker detection process, the magnetic polarity of the magnetic marker 10 is determined depending on whether the peak value when the magnetic marker 10 is detected is positive or negative. In addition, in the marker detection process, the lateral deviation of the vehicle relative to the magnetic marker 10 is identified (measured) by identifying the position of the peak value in the vehicle width direction.

[0022] When the magnetic sensor module 3 executes the marker detection process, it outputs the processing result. The processing result includes information on whether or not the magnetic marker 10 has been detected. Furthermore, when the magnetic marker 10 has been detected, the processing result includes information on the magnetic polarity of the detected magnetic marker 10 and information on the lateral deviation relative to the magnetic marker 10.

[0023] As described above, the magnetic sensor module 3 has a magnetic detection area that is long in the vehicle width direction. When multiple magnetic markers 10 are arranged side by side in the vehicle width direction, multiple magnetic markers 10 may be included in the magnetic detection area of ​​the magnetic sensor module 3. The magnetic sensor module 3 is configured to be able to output the magnetic polarity and lateral deviation for each of the multiple magnetic markers 10 that belong to the magnetic detection area.

[0024] The marker system 1 of this example has one of its technical features in the manner in which the magnetic markers 10 are laid at the branching point 121 and the merging point 123. The control method of the vehicle 2 of this example has one of its technical features in the branching control from the main line 110 to the side road 120, and the merging control from the side road 120 to the main line 110. The branching control and merging control of this example are controls that utilize the manner in which the magnetic markers 10 are laid at the branching point 121 or the merging point 123.

[0025] (Magnetic marker installation) The manner in which magnetic markers 10 are laid at a branch point 121 from the main line 110 to the side road 120 is as shown in Figure 5. At the branch point 121, a marker array line 124 on which magnetic markers 10 are arranged on the side road 120 branches off diagonally from a marker array line 114 on which magnetic markers 10 are arranged on the main line 110. At the branch point 121, the lateral distance between the magnetic markers 10 on the main line 110 and the magnetic markers 10 on the side road 120 gradually increases depending on the distance in the direction of travel from the branch point 118. In the following description, the position where the marker array line 114 and the marker array line 124 branch off is referred to as the branch point 118.

[0026] On the main line 110, a parallel section S1, which is an example of a predetermined section, is provided from a point 6 m before the branch point 118 to the branch point 118. The parallel section S1 is a section in which a secondary magnetic marker 10A is provided alongside a primary magnetic marker 10M provided on the main line 110. The secondary magnetic marker 10A at the branch point 121 is positioned offset to the branching side relative to the primary magnetic marker 10M in the width direction (horizontal direction) of the track 100.

[0027] In the 6m parallel section S1, four main magnetic markers 10M and four secondary magnetic markers 10A are installed. The horizontal distance (perpendicular to the route direction) between the main magnetic markers 10M and the secondary magnetic markers 10A is constant at 0.3m.

[0028] The manner in which the magnetic markers 10 are laid at the junction 123 where the side road 120 merges with the main road 110 is as shown in Figure 6. At the junction 123, a marker array line 124 on which magnetic markers 10 are arranged on the side road 120 merges diagonally with a marker array line 114 on which magnetic markers 10 are arranged on the main road 110. At the junction 123, as the distance to the junction 118 becomes shorter, the lateral distance between the magnetic markers 10 on the main road 110 and the magnetic markers 10 on the side road 120 gradually decreases. In the following description, the position where the marker array line 114 and the marker array line 124 merge is referred to as the junction 119.

[0029] On the main line 110, a parallel section S2, which is an example of a predetermined section, is provided starting from the junction 119 and extending to a point 6 m past the junction 119. In the parallel section S2, a secondary magnetic marker 10A is provided alongside a primary magnetic marker 10M arranged on the main line 110. The secondary magnetic marker 10A at the junction point 123 is positioned offset to the merging side relative to the primary magnetic marker 10M in the width direction of the track 100.

[0030] In the 6m parallel section S2, four main magnetic markers 10M and four secondary magnetic markers 10A are installed. The horizontal distance (perpendicular to the route direction) between the main magnetic markers 10M and the secondary magnetic markers 10A is constant at 0.3m.

[0031] If a certain distance is maintained between the two magnetic markers 10 arranged side by side, the distribution of magnetic measurement values ​​in the vehicle width direction by the magnetic sensor module 3 will be as shown in Fig. 7. With the magnetic distribution shown in the figure, the peaks corresponding to the magnetic markers 20 can be distinguished, and each magnetic marker 10 can be detected.

[0032] On the other hand, if the distance between two side-by-side magnetic markers 10 becomes too narrow, it becomes more difficult to detect the peaks corresponding to each magnetic marker 10, as shown in the example of Fig. 8. This is because the magnetic distributions originating from each magnetic marker 10 overlap and become integrated. In the case of the magnetic distribution shown in the example of Fig. 8, it is possible to detect the presence of a magnetic source, but it becomes more difficult to distinguish and detect each magnetic marker 10.

[0033] If the spacing between two horizontally arranged magnetic markers 10 is too narrow, it is advisable to combine them with different magnetic polarities. In this case, as shown in the distribution of magnetic measurement values ​​in Figure 9, a positive peak value appears corresponding to the magnetic marker 10N with a north pole, and a negative peak value appears corresponding to the magnetic marker 10S with a south pole. With this combination of magnetic markers 10N and 10S with different magnetic polarities, each magnetic marker 10 can be relatively easily distinguished and detected, even if the spacing between horizontally adjacent magnetic markers 10 is the same as in Figure 8.

[0034] The inventors have found the following through verification experiments and simulations: If the interval between horizontally adjacent magnetic markers 10 exceeds 0.3 m, the magnetic markers 10 can be easily distinguished and detected even if they have the same magnetic polarity. On the other hand, if the interval between horizontally adjacent magnetic markers 10 is 0.3 m or less, the processing load for distinguishing and detecting the magnetic markers 10 increases when the magnetic polarity is the same.

[0035] Therefore, in this example, the magnetic polarity combinations of the two magnetic markers 10 are set according to the horizontal distance as shown in Fig. 10. When the distance between the two magnetic markers 10 is 0.3 m or less, different magnetic polarity combinations are used, and when the distance between the two magnetic markers 10 is more than 0.3 m, the same magnetic polarity combination is used.

[0036] In this example, the distance between two horizontally adjacent magnetic markers 10 in the parallel sections S1 and S2 (see Figures 11 and 12) at the branch point 121 and the merging point 123 is 0.3 m. Therefore, in the parallel sections S1 and S2, two horizontally adjacent magnetic markers 10 have different magnetic polarities. Furthermore, in this example, in the parallel sections S1 and S2, the magnetic markers 10 are installed so that the magnetic polarities of the main magnetic marker 10M and the secondary magnetic marker 10A alternate along the direction of the route.

[0037] 11 and 12, magnetic markers 10 with north poles are indicated by black circles, and magnetic markers 10 with south poles are indicated by white circles. These figures are based on FIGS. 5 and 6, but with the addition of information to distinguish the magnetic polarity of each magnetic marker 10. In this example, the magnetic polarity of all magnetic markers 10 other than those in the parallel installation section is set to north pole.

[0038] Among the magnetic markers 10 on the main line 110, the magnetic marker 10 immediately after passing the junction 118 (see FIG. 11) is spaced 0.3 m or less from the magnetic marker 10 on the side road 120 next to it. Therefore, these two side-by-side magnetic markers 10 also have a combination of different magnetic polarities. In the configuration example of FIG. 11, the magnetic polarities of these two side-by-side magnetic markers 10 located immediately after passing the junction 118 are continuous with the magnetic polarity of the magnetic markers 10M·A in the parallel section S1 just before the junction 118. In other words, the magnetic polarity of the magnetic marker 10 on the main line 110 located immediately after passing the junction 118 is different from that of the main magnetic marker 10M on the main line 110 located at the junction 118. Furthermore, the magnetic marker 10 on the side road 120 located immediately after passing the branch point 118 and the secondary magnetic marker 10A located at the branch point 118 have different magnetic polarities.

[0039] Of the magnetic markers 10 on the main line 110, the magnetic marker 10 just before the junction 119 (see Figure 12) is spaced 0.3 m or less from the magnetic marker 10 on the side road 120 next to it. Therefore, these two side-by-side magnetic markers 10 also have different combinations of magnetic polarity. The magnetic polarity of these two side-by-side magnetic markers 10 located just before the junction 119 is set to be continuous with the magnetic markers 10M·A in the parallel section S2 following the junction 119. This continuity is the same as at the branch point 121.

[0040] Next, we will explain branch control and merging control, which are control methods for vehicle 2. Branch control is a control method that utilizes the installation mode of magnetic markers 10 at branch point 121. Merging control is a control method that utilizes the installation mode of magnetic markers 10 at merging point 123. Branch control and merging control will be explained with reference to the flow diagram in Figure 13.

[0041] While the vehicle 2 is traveling on the road 100, the control unit 20 controls the magnetic sensor module 3 to repeatedly execute the marker detection process. As described above, the marker detection process is a process that attempts to detect the magnetic marker 10, determines the magnetic polarity of the detected magnetic marker 10, and measures the lateral deviation of the vehicle 2 with respect to the detected magnetic marker 10.

[0042] When the control unit 20 acquires a processing result indicating that a magnetic marker 10 has been detected (S101: YES), it first determines whether two magnetic markers 10 have been detected simultaneously (S102). If one magnetic marker 10 has been detected independently, rather than two magnetic markers 10 simultaneously (S102: NO), it acquires a lateral deviation relative to the magnetic marker 10 from the processing result (marker detection processing) by the magnetic sensor module 3 (S128). The control unit 20 executes steering control using this lateral deviation as a control amount (S109).

[0043] If it is determined in step S102 that two magnetic markers 10 have been detected simultaneously (S102: YES), the control unit 20 determines the combination of magnetic polarities of the two detected magnetic markers 10 (S103). As described above, the processing results by the magnetic sensor module 3 when two magnetic markers 10 are detected simultaneously include information on the magnetic polarity of each magnetic marker 10 and two types of lateral deviations for each magnetic marker 10.

[0044] If the magnetic polarities of the two simultaneously detected magnetic markers are the same (S102: YES → S103: SAME), the control unit 20 maintains the magnetic marker 10 to be followed (the following marker in FIG. 13) as is (S117). In this step S117, the control unit 20 first reads the lateral deviation that was the control amount for steering control when the immediately preceding magnetic marker was detected. Then, of the two types of lateral deviations for the two simultaneously detected magnetic markers 10, the control unit 20 selects the magnetic marker 10 associated with the lateral deviation that has the smaller difference from the immediately preceding lateral deviation, thereby maintaining the magnetic marker 10 to be followed as is. The control unit 20 acquires the lateral deviation for the magnetic marker 10 selected in this way (S118). The control unit 20 executes steering control using this lateral deviation as the control amount (S109).

[0045] If the magnetic polarities of the two simultaneously detected magnetic markers are different (S102: YES → S103: different), the control unit 20 increments the counter N, which has an initial value of zero, by one (S104). If the counter N is one or two (S105: NO), the control unit 20 maintains the magnetic marker 10 to be tracked as is and obtains the lateral deviation in the flow of steps S117 → S118. The control unit 20 performs steering control using this lateral deviation as a control amount (S109).

[0046] When two magnetic markers with different magnetic polarities are detected simultaneously (S101: YES → S102: YES → S103: different) and the counter N reaches three (an example of a predetermined number of times) (S105: YES), the control unit 20 determines whether to branch or merge (S106). Note that whether to branch or merge is determined based on a preset travel route.

[0047] As described above, the travel routes in this example are of two types: a first travel route that travels along the main road 110 without entering the side road 120, and a second travel route that travels along the main road 110 via the side road 120. For example, if the first travel route is set, it is possible to determine in step S106 above that no branching or merging will occur. For example, if the second travel route is set, it is possible to determine in step S106 above that no branching or merging will occur.

[0048] When branching or merging is to occur (S106: YES), the control unit 20 changes (switches) the magnetic marker 10 to be followed from the primary magnetic marker 10M to the secondary magnetic marker 10A, or from the secondary magnetic marker 10A to the primary magnetic marker 10M, and resets the counter N to its initial value of zero. The control unit 20 changes the magnetic marker 10 associated with the lateral deviation that has the smaller difference from the lateral deviation that was the control amount during the immediately preceding steering control, from the two types of lateral deviations for the two magnetic markers 10 detected simultaneously, to the other magnetic marker 10 associated with the lateral deviation that has the larger difference. The control unit 20 acquires the lateral deviation for the other magnetic marker 10 (S108). The control unit 20 executes steering control using this lateral deviation as the control amount (S109).

[0049] On the other hand, if no branching or merging is to occur (S106: NO), the control unit 20 first resets the counter N to an initial value of zero (S116), maintains the following magnetic marker 10 as is (S117), and obtains the lateral deviation relative to the magnetic marker 10 (S118). The control unit 20 performs steering control using this lateral deviation as a control amount (S109).

[0050] The control flow will be explained below for each driving pattern.

[0051] (branching patterns) When passing through the branch point 121, the processing result (marker detection processing) that the combination of magnetic polarities of the two simultaneously detected magnetic markers 10 is different occurs consecutively (S101 → S102: YES → S103: different), and the counter N becomes 3 (S105: YES). This causes the process to proceed to step S106, and a decision is made to branch, so the magnetic marker 10 to be followed is changed from the previous primary magnetic marker 10M to the secondary magnetic marker 10A (S106: YES → S107). Thereafter, the state of following the secondary magnetic marker 10A shifts to a state of following the magnetic marker 10 on the side road 120, and the vehicle 2 branches onto the side road 120.

[0052] (Straight ahead pattern without branching) Even if the vehicle 2 passes the branch point 121 and continues going straight, the processing result (marker detection processing) that the combination of magnetic polarities of the two simultaneously detected magnetic markers 10 is different occurs continuously (S101 → S102: YES → S103: YES), and the counter N becomes 3 (S105: YES). In the case of going straight, after a determination that there will be no branch in step S106, the magnetic marker 10 to be followed remains the main magnetic marker 10M, which is the magnetic marker of the main line 110 (S117). This allows the vehicle 2 to go straight on the main line 110 without branching onto the side road 120.

[0053] (Converging pattern) When a vehicle 2 traveling on the side road 120 merges onto the main road 110, the processing result (marker detection processing) that the combination of magnetic polarities of the two magnetic markers 10 detected simultaneously is different occurs continuously (S101 → S102: YES → S103: YES). While the counter N is 1 or 2 (S105: NO), the flow of steps S105: NO → S117 causes the vehicle 2 to follow the secondary magnetic marker 10A connected to the magnetic marker 10 on the side road 120.

[0054] When the counter N reaches three (S105: YES), a decision to merge is made in step S106, and the magnetic marker 10 to be followed is changed from the secondary magnetic marker 10A connected to the magnetic marker 10 on the side road 120 to the primary magnetic marker 10M (S106: YES → S107). As a result, the vehicle 2 transitions to a state in which it travels on the main line 110 following the primary magnetic marker 10M, and merges onto the main line 110.

[0055] (Pattern where main line vehicles pass through the merging point) Even when a vehicle on the main line 110 passes through the merging point 123, the processing result (marker detection processing) that the combination of magnetic polarities of the two simultaneously detected magnetic markers 10 is different occurs consecutively (S101 → S102: YES → S103: YES), and the counter N becomes 3 (S105: YES). When passing through the merging point 123, the magnetic marker 10 to be followed remains the main magnetic marker 10M, which is the magnetic marker 10 on the main line 110, based on the determination in step S106 that there will be no merging (S117). This allows the vehicle 2 to continue straight on the main line 110.

[0056] As described above, the marker system 1 of this example is a system with excellent characteristics that contribute to improved control when a vehicle 2 branches off or merges. On a road to which this marker system 1 is applied, the vehicle 2 can branch off or merge with high precision. Furthermore, in this marker system 1, the two magnetic markers 10, which are placed side by side with a small gap between them, have a combination of different magnetic polarities.

[0057] For example, two magnetic markers 10 lined up side by side with a narrow gap of 0.3 m may simultaneously belong to the magnetic detection area of ​​the magnetic sensor module 3. When two magnetic markers 10 of the same magnetic polarity belong to the magnetic detection area, the processing load for distinguishing and detecting each magnetic marker 10 from the magnetic distribution in the vehicle width direction increases. On the other hand, if the magnetic polarities of the two magnetic markers 10 are different, it is relatively easy to distinguish and detect each magnetic marker 10 from the magnetic distribution in the vehicle width direction.

[0058] In the configuration of this example, the magnetic polarity of the main magnetic marker 10M alternates between the parallel sections S1 and S2. This configuration can be used to control a vehicle. In step S104 of the flow diagram of Figure 13 described above, when the counter is N=1 or N=2, a requirement may be added to increment the counter by one in response to detection of a new magnetic marker. For example, a requirement may be added that the left and right positions in the vehicle width direction of the peak corresponding to the N pole and the peak corresponding to the S pole in the magnetic detection area are swapped from the previous magnetic marker detection.

[0059] It is not essential to make the magnetic polarities of the two magnetic markers 10 arranged side by side in the parallel sections S1 and S2 different. Even if two magnetic markers are arranged side by side at an interval of 0.3 m or less, each magnetic marker 10 can be distinguished and detected by ingenious processing. Furthermore, in the configuration of this example, the magnetic polarities of the main magnetic marker 10M and the secondary magnetic marker 10A in the parallel section are alternated along the direction of the route. Alternatively, the magnetic polarities of the main magnetic markers 10M may all be north poles or all may be south poles. It is sufficient that the magnetic polarities of the two magnetic markers 10 arranged side by side in the parallel section are different.

[0060] In this example, the predetermined number (step S105 in FIG. 13) that is the threshold for the number of consecutive occurrences (counter N) of simultaneous detection of two magnetic markers 10 with different magnetic polarities is set to three, regardless of whether branch control or merging control is being used. It is also possible to set a different threshold for the number of consecutive occurrences depending on whether branch control or merging control is being used.

[0061] In this example, parallel sections S1 and S2 are relatively short at 6 m, but the parallel sections S1 and S2 may be longer. The parallel sections S1 and S2 may have different section lengths. Although 2 m is exemplified as the spacing between magnetic markers along the route, this spacing of 2 m is just one example. The spacing between magnetic markers may be changed, and may also be changed depending on the shape and structure of the route. In the parallel sections S1 and S2, the spacing between magnetic markers 10 may be shorter, such as 1 m or 0.5 m, rather than 2 m.

[0062] The magnetic polarity of the magnetic markers 10 may be arbitrary, regardless of whether they are on the main road 110 or the side road 120, except for the branching point 121 and the merging point 123. In this case, there is no need to manage the magnetic polarity of the magnetic markers 10 when laying them, which reduces installation costs. The magnetic polarity of the magnetic markers 10 may be arbitrary, including at the branching point 121 and the merging point 123.

[0063] Example 2 This example is based on the marker system of Example 1, and is a configuration example in which the magnetic polarity of the magnetic markers 10 is all optional, regardless of whether the location is a branch point 121 or a merging point 123. The control method in this configuration will be described with reference to the flow chart in FIG.

[0064] The process in Figure 14 differs from the process in Figure 13 in two ways: the decision step of step S103 is omitted, and step S105 is replaced with step S205. In the process in Figure 14, when simultaneous detection of two magnetic markers 10 occurs four times in a row (S205: YES), a decision is made as to whether to branch or merge (S106).

[0065] The reason for increasing the threshold for the number of simultaneous detections of two magnetic markers 10 in step S205 is that simultaneous detection of a magnetic marker 10 on the main road 110 and a magnetic marker 10 on the side road 120 may occur just before the parallel section S2 at the merging point 123 (see FIG. 12). By increasing the threshold for the number of simultaneous detections of two magnetic markers 10, it is possible to avoid the risk of step S205 being executed when the vehicle 2 is just before the parallel section S2.

[0066] On the other hand, if the threshold value for the number of simultaneous detections of the two magnetic markers 10 in step S205 is set large, there is a risk that the timing for switching the following magnetic marker 10 from the main magnetic marker 10M to the secondary magnetic marker 10A when branching from the main road 110 to the side road 120 may be delayed. Therefore, it is also possible to make the section length of the parallel section S1 at the branch point 121 (see FIG. 11 ) longer than the section length of the parallel section S2 at the merging point 123. In this case, when the vehicle 2 branches, it is possible to switch the following magnetic marker 10 with high reliability at a position just before the branch point 118. Alternatively, it is also possible to make the section length of the parallel section S1 the same as that of the parallel section S2, while making the threshold value for the number of simultaneous detections corresponding to the branching point 121 smaller than the threshold value corresponding to the merging point 123. The other configurations and effects are the same as those of the first embodiment.

[0067] 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 specific examples using publicly known technology and the knowledge of those skilled in the art. [Explanation of symbols]

[0068] 1. Marker System 10 Magnetic Markers 100 Runway (Route) 10A Secondary magnetic marker 10M Primary Magnetic Marker 110 Main Line 114 Marker array line (main line) 118 Branching Point 119 Confluence 120 Side roads (routes branching off from the main road, routes joining the main road) 121 Branching Point 123 Confluence 124 Marker array line (side road) 2 vehicles 20 Control Unit 3 Magnetic sensor module (magnetic detection circuit)

Claims

1. A control method for a vehicle having a magnetic detection circuit with a magnetic detection area that is long in the vehicle width direction, for driving while detecting magnetic markers that are placed at intervals along a route, comprising: The route includes, in addition to the route forming the main line, at least one of a route branching from the route forming the main line starting from a branch point and a route merging with the route forming the main line at a junction point; In a predetermined section of the route forming the main line before the branch point or a predetermined section past the junction, a secondary magnetic marker is arranged so as to be detected simultaneously with a primary magnetic marker arranged on the route forming the main line by the magnetic detection circuit having a magnetic detection area that is long in the vehicle width direction, at least one of branch control for allowing a vehicle to enter the branching route from the route forming the main line and merging control for allowing a vehicle to merge from the merging route onto the route forming the main line, the branching control is a control that, when simultaneous detection of the primary magnetic marker and the secondary magnetic marker occurs consecutively a predetermined number of times, switches from control that follows the primary magnetic marker to control that follows the secondary magnetic marker, and causes the vehicle to travel by following the magnetic markers arranged along the branching routes after passing the branching point; The merging control is a vehicle control method in which, upon passing the merging point, a control state in which the vehicle travels by following magnetic markers placed along the merging route is transitioned to a control state in which the vehicle travels along the route forming the main line by following the secondary magnetic marker, and when simultaneous detection of the primary magnetic marker and the secondary magnetic marker occurs consecutively a predetermined number of times, a control is executed to switch from control that follows the secondary magnetic marker to control that follows the primary magnetic marker.

2. According to claim 1, the magnetic polarity combination of the primary magnetic marker and the secondary magnetic marker that can be simultaneously detected varies depending on whether the distance between the primary magnetic marker and the secondary magnetic marker is equal to or less than a predetermined threshold value, When the distance between the primary magnetic marker and the secondary magnetic marker is equal to or less than a predetermined threshold, the magnetic polarity combination is a different magnetic polarity combination; A vehicle control method, wherein the magnetic polarity combination is the same when the distance between the primary magnetic marker and the secondary magnetic marker exceeds or is equal to or greater than a predetermined threshold.

3. 3. A vehicle control method according to claim 1, wherein the primary magnetic markers that can be detected simultaneously with the secondary magnetic markers are arranged so that their magnetic polarities alternate along the route that forms the main road.

4. A marker system that arranges magnetic markers along a route traveled by a vehicle having a magnetic detection circuit with a magnetic detection area that is long in the vehicle width direction, The route includes, in addition to the route forming the main line, at least one of a route branching from the route forming the main line starting from a branch point and a route merging with the route forming the main line at a junction point; A marker system characterized in that, in a predetermined section of the route that forms the main line, just before the branch point or just past the merging point, a secondary magnetic marker is arranged so that it can be detected simultaneously with the primary magnetic marker arranged on the route that forms the main line by the magnetic detection circuit, which has a magnetic detection area that is long in the vehicle width direction.

5. In claim 4, the combination of magnetic polarities of the primary magnetic marker and the secondary magnetic markers that can be detected simultaneously varies depending on whether the distance between the primary magnetic marker and the secondary magnetic marker is equal to or less than a predetermined threshold value, When the distance between the primary magnetic marker and the secondary magnetic marker is equal to or less than a predetermined threshold, the magnetic polarity combination is a different magnetic polarity combination; A marker system, wherein the magnetic polarity combination is the same magnetic polarity combination if the distance between the primary magnetic marker and the secondary magnetic marker exceeds or is equal to or greater than a predetermined threshold.

6. 6. A marker system according to claim 4 or 5, wherein the main magnetic markers that can be detected simultaneously with the secondary magnetic markers are arranged so that their magnetic polarities alternate along the main line path.

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