Magnetic detection system and magnetic detection method

Abstract

To provide a system that can efficiently determine the longitudinal position in a system where a vehicle travels while detecting a magnetic tape. [Solution] A magnetic detection system 1 for a vehicle 2 traveling along a path 11R in which magnetic pieces 10P are arranged alongside a magnetic tape 10T laid along the path 11R, to detect the magnetic tape 10T and magnetic pieces 10P comprises a magnetic unit 3 attached to the vehicle 2 such that the arrangement direction of the plurality of magnetic sensors is aligned with the vehicle width direction, and a detection circuit that performs detection processing for magnetically detecting the magnetic tape 10T and magnetic pieces 10P. The detection circuit is configured to detect both the magnetic tape 10T and magnetic pieces 10P by processing the magnetic measurement values ​​from each magnetic sensor of the magnetic unit 3.

Description

Technical Field

[0001] The present invention relates to a magnetic detection system and a magnetic detection method for detecting magnetic products laid on the road surface of a vehicle.

Background Art

[0002] Conventionally, as a system for automating the logistics within facilities such as factories and warehouses, a system in which magnetic tapes are laid along a route is known. In this system, a transport vehicle travels while detecting the magnetic tape and following the magnetic tape. On the other hand, in a system using a magnetic tape, it is not easy to specify the position in the longitudinal direction of the magnetic tape, which poses a technical problem. Therefore, for example, a system in which magnetic markers indicating specific positions such as stop positions are arranged side by side on the magnetic tape has been proposed (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Vehicles constituting the conventional system use a magnetic sensor array for detecting a magnetic tape and a magnetic sensor for detecting a magnetic marker, and need to separately execute processing for detecting the magnetic tape and processing for detecting the magnetic marker, resulting in a redundant system both in terms of hardware and software.

[0005] The present invention has been made in view of the above-mentioned conventional problems, and aims to provide a system and method capable of efficiently specifying the longitudinal position in a system in which a vehicle travels while detecting a magnetic tape.

Means for Solving the Problems

[0006] One aspect of the present invention is a magnetic detection system for detecting the magnetic tape and the one or more magnetic pieces in a vehicle traveling along a path in which a magnetic tape is laid along the path and one or more individual magnetic pieces are arranged side by side on the magnetic tape, A magnetic unit is mounted on a vehicle such that multiple magnetic sensors capable of measuring the magnitude of the magnetic field acting from the road surface are arranged linearly, and the direction of this arrangement is aligned with the vehicle width direction. The system includes a detection circuit that performs a detection process for magnetically detecting the magnetic tape and the one or more magnetic pieces, The detection circuit is part of a magnetic detection system configured to detect the magnetic tape and each of the magnetic pieces by processing the magnetic measurement values ​​from each of the magnetic sensors in the magnetic unit.

[0007] One aspect of the present invention is a method for detecting the magnetic tape and the one or more magnetic pieces by a vehicle traveling along a path in which a magnetic tape is laid along the path and one or more individual magnetic pieces are arranged side by side on the magnetic tape, The vehicle is equipped with a magnetic unit consisting of multiple magnetic sensors arranged linearly, capable of measuring the magnitude of the magnetic field acting from the road surface, and is mounted along the width of the vehicle. The process includes a detection process for magnetically detecting the magnetic tape and the one or more magnetic pieces. The detection process involves detecting the magnetic tape and each of the magnetic pieces by processing the magnetic measurement values ​​from each magnetic sensor of the magnetic unit. [Effects of the Invention]

[0008] The present invention relates to a system or method for a vehicle traveling along a path in which a magnetic tape is laid along the path and one or more magnetic pieces are arranged parallel to the magnetic tape. In the vehicle according to the present invention, a magnetic unit in which a plurality of magnetic sensors are arranged linearly is mounted so that the direction of arrangement is aligned with the vehicle width direction. According to the magnetic detection system and magnetic detection method of the present invention, the magnetic tape and one or more magnetic pieces can be efficiently detected by processing the magnetic measurement values ​​from each magnetic sensor. [Brief explanation of the drawing]

[0009] [Figure 1] Diagram illustrating the magnetic detection system in Example 1. [Figure 2] A diagram showing the location where magnetic pieces are arranged side by side in front of the curve in Example 1. [Figure 3] A diagram illustrating the vehicle in Example 1. [Figure 4] A block diagram showing the electrical configuration of the vehicle in Example 1. [Figure 5] Block diagram of the magnetic unit in Example 1. [Figure 6] A flowchart showing the operation flow of the magnetic unit in Example 1. [Figure 7] A diagram showing how the vehicle travels along the magnetic tape in Example 1. [Figure 8] This graph shows the approximate curve of the magnetic intensity distribution in the vehicle width direction (upper panel) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower panel) when the vehicle is traveling along the magnetic tape in Example 1. [Figure 9] This diagram shows how a vehicle approaches the location where magnetic pieces are arranged side by side just before a right curve in Example 1. [Figure 10] The graph shows the approximate curve of the magnetic intensity distribution in the vehicle width direction (upper panel) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower panel) when a vehicle passes through the section where magnetic pieces are arranged side by side before a right curve in Example 1. [Figure 11]Explanatory drawing exemplifying information attached to the parallel arrangement pattern of magnetic pieces in Example 1. [Figure 12] Figure showing the state where a vehicle approaches the parallel arrangement location of magnetic pieces in front of the left curve in Example 1. [Figure 13] Graph showing the approximate curve of the magnetic intensity distribution in the vehicle width direction (upper part) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower part) when the vehicle passes through the parallel arrangement location of magnetic pieces in front of the left curve in Example 1. [Figure 14] Figure showing the state where a vehicle approaches the parallel arrangement location of magnetic pieces in front of the stop position in Example 1. [Figure 15] Graph showing the approximate curve of the magnetic intensity distribution in the vehicle width direction (upper part) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower part) when the vehicle passes through the parallel arrangement location of magnetic pieces in front of the stop position in Example 1. [Figure 16] Figure showing a section where a plurality of parallel arrangement locations of magnetic pieces are provided along the magnetic tape in Example 1. [Figure 17] Figure showing Parallel arrangement pattern 1 of magnetic pieces in Example 2. [Figure 18] Approximate curve of the magnetic intensity distribution in the vehicle width direction (upper part) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower part) when passing through the parallel arrangement location of Parallel arrangement pattern 1 in Example 2 [Figure 19] Figure showing Parallel arrangement pattern 2 of magnetic pieces in Example 2. [Figure 20] Approximate curve of the magnetic intensity distribution in the vehicle width direction (upper part) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower part) when passing through the parallel arrangement location of Parallel arrangement pattern 2 in Example 2 [Figure 21] Figure showing the zero - cross separation distances a and b for Parallel arrangement pattern 2 of magnetic pieces in Example 2. [Figure 22] Figure showing Parallel arrangement pattern 3 of magnetic pieces in Example 2. [Figure 23] Approximate curve of the magnetic intensity distribution in the vehicle width direction (upper part) and the approximate curve of the magnetic gradient distribution in the vehicle width direction (lower part) when passing through the parallel arrangement location of Parallel arrangement pattern 3 in Example 2 [Figure 24] This figure shows the zero-crossing distances c and d for the third arrangement pattern of magnetic pieces in Example 2. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be specifically described using the following examples. (Example 1) This example relates to a magnetic detection system 1 capable of efficiently detecting magnetic strips 10P arranged in parallel with a magnetic tape 10T. This will be explained using Figures 1 to 16.

[0011] The magnetic detection system 1 in this example (Figure 1) can be applied, for example, to a transport system 11 in a facility such as a factory or warehouse. In the transport system 11, a path 11R for moving the vehicle 2 is pre-set. On the floor surface of the path 11R, a magnetic tape 10T is laid continuously along the center of the path 11R. The transport system 11 in this example is a system that makes the vehicle 2 travel along the path 11R by steering it so that the lateral deviation relative to the magnetic tape 10T approaches zero.

[0012] The magnetic tape 10T is a magnetic product that, for example, has a continuous strip shape with a width of 100 mm and a thickness of 2 mm. The magnetic tape 10T has a structure in which a magnetic material is laminated on the surface of a base tape made of a resin material such as polypropylene. The magnetic material is, for example, a magnetic material in which iron oxide magnetic powder is dispersed in a polymer material. In the magnetic tape 10T, the magnetic polarity is different on both sides. In this example, the magnetic tape 10T is laid so that the upper surface is the north pole and the lower surface, which is the side attached to the floor, is the south pole. It is also possible to have the south pole of the magnetic tape 10T on the upper surface.

[0013] Along the route 11R, there are locations where it is necessary to accurately determine the position of the magnetic tape 10T in the longitudinal direction, such as the position before a curve or before a stop line. In the transport system 11, these locations are represented by the parallel arrangement of magnetic pieces 10P, as shown in Figure 2. The transport system 11 can accurately determine the position of the vehicle 2 in the longitudinal direction of the magnetic tape 10T by utilizing the magnetic pieces 10P. The transport system 11 uses the magnetic pieces 10P to provide the vehicle 2 with information about approaching curves and stopping positions.

[0014] In this example, multiple patterns are set as the parallel arrangement patterns for the magnetic pieces 10P. Different information is provided to the vehicle 2 for each parallel arrangement pattern. In this example, three types of parallel arrangement patterns are set corresponding to right curves, left curves, and stopping positions. The parallel arrangement pattern corresponding to a right curve is a pattern in which the S-pole magnetic piece 10P is placed adjacent to the right side of the magnetic tape 10T in the direction of travel of the vehicle 2. The parallel arrangement pattern corresponding to a left curve is a pattern in which the S-pole magnetic piece 10P is placed adjacent to the left side of the magnetic tape 10T in the direction of travel of the vehicle 2. The parallel arrangement pattern corresponding to a stopping position is a pattern in which the S-pole magnetic piece 10P is placed adjacent to both sides of the magnetic tape 10T. Note that there may be more than three types of parallel arrangement patterns. Other parallel arrangement patterns will be illustrated in Embodiment 2 described later.

[0015] The magnetic piece 10P (Figure 2) is a magnetic product made by cutting the magnetic tape 10T into 100mm lengths. Since the width of the magnetic tape 10T is 100mm, the magnetic piece 10P is a square sheet with sides of 100mm. The magnetic piece 10P is attached to the floor surface adjacent to the side of the magnetic tape 10T. In this example, the magnetic piece 10P is laid so that its magnetic polarity is different from that of the magnetic tape 10T. Since the surface of the magnetic tape 10T is the north pole, the magnetic piece 10P is laid so that its surface is the south pole.

[0016] Next, the vehicle 2 that constitutes the magnetic detection system 1 in this example will be described. As shown in Figure 3, vehicle 2 is a vehicle with a length of 2m and a width of 1m. Vehicle 2 is a four-wheeled vehicle equipped with front wheels 21 which are steering wheels and a pair of left and right rear wheels 22 which are drive wheels. In vehicle 2, the magnetic unit 3 is mounted in front of the front wheels 21. Note that the arrangement of the magnetic unit 3 is not limited to the configuration in this example, and it may be located between the front wheels 21 and the rear wheels 22, or behind the rear wheels 22. As will be described in detail later, in addition to the function of detecting the magnetic tape 10T and magnetic pieces 10P laid on the floor surface, the magnetic unit 3 in this example has the function of acquiring information on the locations where the magnetic pieces 10P are arranged side by side. The information acquired by the magnetic unit 3 is used for the driving control of vehicle 2.

[0017] Vehicle 2 is electrically configured around a control unit 40, as shown in Figure 4. The control unit 40 is connected to a magnetic unit 3, a motor unit 44 that rotates the rear wheels 212, a wheel speed sensor 442 for the rear wheels 212, a steering unit 46 that steers the front wheels 211 which are the steering wheels, and so on.

[0018] The control unit 40 is a circuit that includes a CPU for performing various calculations, memory elements such as ROM and RAM, etc. The control unit 40 inputs control values ​​to the steering unit 46 and the motor unit 44. The control value for the steering unit 46 is the target steering angle for the steering angle of the front wheels 21. The control value for the motor unit 44 is the target rotational angular velocity for the rotational angular velocity of the rear wheels 22. The control unit 40 controls the steering angle of the front wheels 21 via the steering unit 46 and controls the rotational angular velocity of the rear wheels 22 via the motor unit 44.

[0019] While detecting the magnetic tape 10T, the control unit 40 controls the steering angle of the front wheels 211 so that the lateral deviation of the vehicle 2 relative to the magnetic tape 10T is a predetermined value. Furthermore, when the control unit 40 obtains information about the locations where the magnetic pieces 10P are arranged side-by-side from the magnetic unit 3, it executes corresponding control. For example, if the location is before a right-hand curve, it executes control to reduce speed in preparation for steering. For example, if the location is before a stopping position, it executes control to stop the vehicle 2.

[0020] The transport system 11 in this example incorporates a magnetic detection system 1 for detecting magnetic products, namely a magnetic tape 10T and a magnetic piece 10P. The magnetic detection system 1 is configured using a magnetic unit 3. In the magnetic detection system 1 in this example, the magnetic unit 3 is used for both detecting the magnetic tape 10T and detecting the magnetic piece 10P.

[0021] The magnetic unit 3 (Figure 5) is a unit in which multiple magnetic sensors are arranged in a straight line. The magnetic unit 3 includes a signal acquisition circuit 31 that acquires sensor signals from each magnetic sensor, a detection circuit 33 that performs detection processing of magnetic products (magnetic tape 10T, magnetic pieces 10P), an information acquisition circuit 34 that acquires information on the locations where the magnetic pieces 10P are arranged side by side, and an information DB 38 that stores information for each arrangement pattern of the magnetic pieces 10P.

[0022] In the magnetic unit 3 (Figure 5), 15 magnetic sensors An (where n is the magnetic sensor number, a natural number from 1 to 15) are arranged linearly at 5 cm intervals. The magnetic unit 3 is mounted on the vehicle 2 such that the arrangement direction of the magnetic sensors An is aligned with the vehicle width direction. With the magnetic unit 3, in which multiple magnetic sensors An are positioned along the vehicle width direction, it is possible to measure the lateral deviation of the vehicle 2 relative to the magnetic tape 10T.

[0023] In magnetic unit 3, for example, a high-precision MI (Magnet Impedance) sensor is used as the magnetic sensor. The MI sensor is a high-precision magnetic sensor that utilizes the well-known MI effect (Magnet Impedance Effect). The MI effect is a magnetic effect in which the impedance of a magnetosensitive material, such as an amorphous wire, changes sensitively in response to an external magnetic field. The magnetic sensor An (where n is a natural number from 1 to 15) is incorporated into magnetic unit 3 so as to be able to measure the strength of a magnetic field acting in the vertical direction.

[0024] The detection circuit 33 (Figure 5) is an arithmetic circuit that performs detection processing for detecting the magnetic tape 10T and the magnetic piece 10P. Although not shown in the figure, the detection circuit 33 is composed of a CPU (central processing unit) that performs various calculations, memory elements such as ROM (read-only memory) and RAM (random access memory), etc.

[0025] The detection circuit 33 outputs the detection result of the magnetic tape 10T and the detection result of the magnetic piece 10P. The detection result of the magnetic tape 10T includes a signal indicating whether or not the magnetic tape 10T is detected, the lateral deviation relative to the magnetic tape 10T, etc. The detection result of the magnetic piece 10P includes information indicating the presence or absence of adjacent magnetic pieces 10P (whether or not they are adjacent), the arrangement of the magnetic pieces 10P relative to the magnetic tape 10T (adjacent arrangement pattern), etc.

[0026] The information acquisition circuit 35 (Figure 5) is an arithmetic circuit that acquires information corresponding to the parallel arrangement pattern of the magnetic pieces 10P. Although not shown in the figure, the information acquisition circuit 35 is composed of a CPU (central processing unit) that performs various calculations, memory elements such as ROM (read-only memory) and RAM (random access memory), etc.

[0027] The information database (information DB) 38 (Figure 5) is an example of a memory circuit that stores information about the locations where magnetic pieces 10P are arranged side by side. In the information DB 38, information is stored linked to the arrangement patterns of the magnetic pieces 10P. As described above, in this example, three types of arrangement patterns for the magnetic pieces 10P are set. The three types of arrangement patterns are a pattern corresponding to a right curve, a pattern corresponding to a left curve, and a pattern corresponding to a stopping position. The way information is stored in the information DB 48 will be explained in detail later.

[0028] In this example, to facilitate understanding of the function of the magnetic unit 3, the detection circuit 33, the information acquisition circuit 35, and the information DB 38 are described as separate configurations. However, all or any two of these configurations may be integrated into a single unit.

[0029] Next, the operation of the magnetic unit 3 will be explained with reference to the flowchart in Figure 6. The 15 magnetic sensors An measure magnetic intensity at the same time and output sensor signals representing magnetic intensity (S101). The 15 channels of sensor signals are input to the signal acquisition circuit 31. The signal acquisition circuit 31, which is a 15-channel AD conversion circuit, converts the 15 channels of sensor signals into digital signals and inputs them to the detection circuit 33. The 15 channels of digital signals input to the detection circuit 33 are magnetic measurement values ​​from each magnetic sensor An arranged in the vehicle width direction, and indicate the magnetic intensity distribution in the vehicle width direction.

[0030] For example, as shown in Figure 7, when vehicle 2 is traveling along the magnetic tape 10T in a section where magnetic pieces 10P are not arranged side by side (a section where magnetic pieces 10P are not arranged side by side), the magnetic intensity distribution in the vehicle width direction exhibits a single-peak distribution with a peak corresponding to the magnetic tape 10T, as shown in the graph of the approximate curve in the upper part of Figure 8.

[0031] The detection circuit 33 applies lateral differential filtering to the 15-channel digital signals (hereinafter referred to as sensor signals) (S102). Lateral differential filtering is a process that determines the magnetic gradient in the vehicle width direction (lateral direction) as the filter output by calculating the difference in sensor signals between adjacent magnetic sensors in the vehicle width direction (lateral direction).

[0032] For example, when vehicle 2 is traveling along magnetic tape 10T in a section where magnetic pieces 10P are not arranged side by side, as shown in Figure 7, the approximate curve of the magnetic gradient distribution in the vehicle width direction is obtained by applying differentiation to the single-peak curve in the upper part of the same figure. This curve is like a combination of a pair of positive and negative peaks, as shown in the graph of the approximate curve in the lower part of Figure 8.

[0033] The detection circuit 33 detects zero-crossings (S103) in the approximate curve of the magnetic gradient distribution obtained by applying a lateral differential filter to the 15 sensor signals acquired simultaneously (signals constituting the magnetic intensity distribution in the upper part of Figure 8). The conditions for detecting a zero-crossing are that the sign of the approximate curve has switched, and that the slope of the approximate curve at the zero-crossing is greater than or equal to a preset slope. When both conditions are met, it is determined that a zero-crossing has occurred. In this example, the detection circuit 33 distinguishes between a first zero-crossing where the magnetic gradient switches from a negative value to a positive value, and a second zero-crossing where the magnetic gradient switches from a positive value to a negative value, and detects the zero-crossing accordingly.

[0034] For example, as shown in Figure 7, when the vehicle 2 is traveling along the magnetic tape 10T rather than along the parallel arrangement of magnetic pieces 10P, the detection circuit 33 can detect the second zero-crossing ZC2 (see the lower graph in Figure 8) in step S103, but it will not detect the first zero-crossing. When the detection circuit 33 has detected the second zero-crossing ZC2 as shown in the lower graph in Figure 8, it determines that it has detected the magnetic tape 10T. The detection circuit 33 treats the position of the second zero-crossing in the vehicle width direction as the center position of the magnetic tape 10T and identifies the lateral deviation of the vehicle 2 relative to the magnetic tape 10T (S104).

[0035] In this example, the magnetic tape 10T is laid along the route 11R, and the vehicle 2 travels along the magnetic tape 10T, so unless some trouble occurs, the magnetic tape 10T will always be detected. As a condition for determining that the magnetic tape 10T has been detected, in addition to detecting the second zero-crossing ZC2, the condition that the magnetic intensity at the location of the second zero-crossing ZC2 is a positive value in the magnetic intensity distribution in the vehicle width direction (upper graph in Figure 8) may also be set.

[0036] The detection circuit 33 detects that if only the second zero-crossing ZC2 corresponding to the magnetic tape 10T (see the lower graph in Figure 8) is detected and the first zero-crossing is not detected, then the detection circuit 33 determines that there are no magnetic pieces 10P in parallel. The detection circuit 33 then determines that there are no magnetic pieces 10P in parallel at that location (S105: NO). In this case, the detection circuit 33 outputs to the control unit 40 that the magnetic tape 10T has been detected, that there are no magnetic pieces 10P in parallel at that location, and the lateral deviation relative to the detected magnetic tape 10T (S108).

[0037] For example, as shown in Figure 9, when vehicle 2 passes over the section where magnetic pieces 10P are arranged side by side before a right curve, the magnetic intensity distribution in the vehicle width direction obtained in step S101 above will exhibit a distribution that includes a positive peak corresponding to the magnetic tape 10T, as shown in the upper magnetic intensity distribution graph in Figure 10, and a series of negative peaks corresponding to the S-pole magnetic piece 10P to its right. In the same figure, the right side of the horizontal axis corresponds to the right side in the direction of travel of vehicle 2. Hereafter, the direction of travel of vehicle 2 will simply be referred to as the direction of travel.

[0038] For example, as shown in Figure 9, when vehicle 2 passes over the section where magnetic pieces 10P are arranged side by side before a right curve, the approximate curve of the magnetic gradient distribution obtained by the lateral differential filter processing in step S102 (Figure 6) is the curve obtained by applying differentiation to the approximate curve of the magnetic intensity distribution in the upper part of Figure 10. This curve is such that, as shown in the graph of the approximate curve in the lower part of the same figure, positive peaks are lined up on both sides of a negative peak.

[0039] According to step S103 (Figure 6) above, a second zero-crossing ZC2 and a first zero-crossing ZC1 are detected in the approximate curve of the magnetic gradient distribution in the lower part of Figure 10. When the detection circuit 33 has detected the second zero-crossing ZC2 as shown in the lower part of the graph in Figure 10, it determines that the magnetic tape 10T has been detected, and in step S104 (Figure 6) as described above, it identifies the lateral deviation of the vehicle 2 relative to the magnetic tape 10T.

[0040] The detection circuit 33 determines whether the first zero-crossing ZC1 corresponds to the magnetic piece 10P when it detects a first zero-crossing ZC1 in addition to the second zero-crossing ZC2 corresponding to the magnetic tape 10T, as shown in the lower magnetic gradient distribution in Figure 10. The detection circuit determines that it has detected the south pole magnetic piece 10P if the magnetic intensity at the location of the first zero-crossing ZC1 is negative in the approximate curve of the magnetic intensity distribution (upper graph in Figure 10), and further determines that it is a location where magnetic pieces 10P are placed side by side (S105: YES in Figure 6). It is also possible to immediately determine that a magnetic piece 10P has been detected when the first zero-crossing ZC1 is detected, and the condition that the magnetic intensity at the location of the first zero-crossing ZC1 is negative may be removed.

[0041] When vehicle 2 reaches a location where magnetic pieces 10P are arranged side by side (S105: YES in Figure 6), the detection circuit 33 identifies the arrangement pattern of magnetic pieces 10P at that location (S106). For example, as shown in Figure 9, when vehicle 2 passes a location where magnetic pieces 10P are arranged side by side before a right curve, as shown in the lower graph of Figure 10, a first zero-crossing ZC1 corresponding to magnetic piece 10P appears to the right of a second zero-crossing ZC2 corresponding to magnetic tape 10T. As shown in Figure 9, the detection circuit 33 identifies arrangement pattern R1 (one on the right) in which one magnetic piece 10P is placed to the right of magnetic tape 10T in the direction of travel.

[0042] When the detection circuit 33 identifies the parallel arrangement pattern of the magnetic pieces 10P (S106), it retrieves the information associated with the identified parallel arrangement pattern from the information DB 38, which is an example of a memory circuit (S107). This information DB 38 is a database in which information is associated with three types of parallel arrangement patterns, as shown in the lookup table (LUT) in Figure 11.

[0043] As described above, the parallel patterns in this example consist of three types: parallel pattern R1 corresponding to a right curve, parallel pattern L1 corresponding to a left curve, and parallel pattern R1L1 corresponding to the stopping position. In the information DB48, the information for a "right curve" is linked to parallel pattern R1, the information for a "left curve" is linked to parallel pattern L1, and the information for the "stopping position" is linked to parallel pattern R1L1.

[0044] When the vehicle 2 passes over a section of magnetic pieces 10P arranged side by side just before a right curve (see Figure 9), the detection circuit 33 identifies the arrangement pattern R1 as described above (S106), and then obtains the "right curve" information associated with the arrangement pattern R1 by referring to the LUT (Figure 11) in the information DB 38 (S107).

[0045] Following its determination that the parallel arrangement section has been reached (S105: YES), the detection circuit 33 acquires information about the parallel arrangement section (S107) and outputs the detection result to the control unit 40 (S108). For example, as shown in Figure 9, the detection result when vehicle 2 passes the parallel arrangement section of magnetic pieces 10P before a right curve includes not only the lateral deviation relative to the magnetic tape 10T but also a notification that the parallel arrangement section before the right curve has been reached.

[0046] For example, as shown in Figure 12, when vehicle 2 passes over the section where magnetic pieces 10P are arranged side by side before a left curve, the 15 sensor signals acquired simultaneously (step S101 in Figure 6) form an approximate curve of the magnetic intensity distribution shown in the upper part of Figure 13. Then, the magnetic gradient distribution obtained by applying a lateral differential filter to this approximate curve of the magnetic intensity distribution (step S102) forms an approximate curve shown in the lower part of Figure 13. In this approximate curve of the magnetic gradient distribution, a first zero-crossing ZC1 corresponding to the south pole magnetic piece 10P appears to the left of the second zero-crossing ZC2 corresponding to the magnetic tape 10T (step S103).

[0047] In this case, the detection circuit 33 identifies a parallel arrangement pattern L1 (one on the left) in which one magnetic piece 10P is placed on the left side of the magnetic tape 10T in the direction of travel (step S106 in Figure 6). The detection circuit 33 refers to the LUT (Figure 11) in the information DB 38 and obtains the "left curve" information associated with the parallel arrangement pattern L1 (step S107).

[0048] Furthermore, as shown in Figure 14, for example, when vehicle 2 passes over the section where magnetic pieces 10P are arranged side by side just before the stopping position, the 15 sensor signals acquired simultaneously (step S101 in Figure 6) form an approximate curve of the magnetic intensity distribution shown in the upper part of Figure 15. Then, the magnetic gradient distribution obtained by applying lateral differential filtering to this approximate curve of the magnetic intensity distribution (step S102 in the same figure) forms an approximate curve shown in the lower part of Figure 15. In this approximate curve of the magnetic gradient distribution, a first zero-crossing ZC1 corresponding to the S-pole magnetic piece 10P appears on both sides of the second zero-crossing ZC2 corresponding to the magnetic tape 10T (step S103 in the same figure).

[0049] In this case, the detection circuit 33 identifies a parallel arrangement pattern R1L1 (one on the right and one on the left) in which one magnetic piece 10P is placed on each side of the magnetic tape 10T (step S106 in Figure 6). The detection circuit 33 refers to the LUT (Figure 11) in the information DB 38 and obtains the "stop position" information associated with the parallel arrangement pattern R1L1 (step S107).

[0050] As described above, the magnetic detection system 1 in this example can efficiently detect both the magnetic tape 10T and the magnetic pieces 10P by processing the 15 channels of sensor signals (magnetic measurement values) output by the magnetic unit 3, in which multiple magnetic sensors An are arranged linearly. In this magnetic detection system 1, without distinguishing in advance whether the magnetic pieces 10P are arranged alongside the magnetic tape 10T or not, both the magnetic tape 10T and each magnetic piece 10P can be detected where they are arranged side by side. In areas where the magnetic pieces 10P are not arranged side by side, it is possible to detect the magnetic tape 10T and also to detect that the magnetic pieces 10P are not arranged side by side.

[0051] In this example, a reversed piece of the magnetic tape 10T is used as the magnetic piece 10P. Individual sheet-like magnetic markers can also be used as magnetic pieces. In this example, the magnetic pieces 10P are placed adjacent to the magnetic tape 10T without any gaps, but a gap may be provided between the magnetic tape 10T and the magnetic piece 10P. Even if a gap is provided, as long as the second zero-crossing corresponding to the magnetic tape 10T and the first zero-crossing corresponding to the magnetic piece 10P can be detected, the arrangement pattern of the magnetic pieces 10P can be identified using the method described in this example.

[0052] Alternatively, as shown in Figure 16, a section can be set up in which parallel locations are continuously provided at narrow intervals along the longitudinal direction of the magnetic tape 10T, and information can be provided to the vehicle 2 by combinations of parallel locations patterns that the vehicle 2 passes through sequentially. For example, if a parallel location pattern in which a south pole magnetic piece 10P is adjacent to the left side of the magnetic tape 10T in the direction of travel is bit 1, and a parallel location pattern in which a south pole magnetic piece 10P is adjacent to the right side is bit 0, then information can be provided to the vehicle 2 by binary data represented by multiple parallel locations. It is advisable to associate binary data with various types of information to be provided to the vehicle 2 in the information DB 38.

[0053] (Example 2) This example shows an example of a parallel arrangement pattern to be added to or replaced in the parallel arrangement pattern of magnetic pieces in Example 1. This will be explained with reference to Figures 17 to 24.

[0054] The side-by-side arrangement pattern in Figure 17 is one in which, facing the direction of travel, the south pole magnetic piece 10P is placed adjacent to the left side of the magnetic tape 10T, and the south pole magnetic piece 10P and the north pole magnetic piece 10P are placed adjacent to the right side of the magnetic tape 10T in that order from the inside. In this side-by-side arrangement pattern, the south pole, the north pole (of the magnetic tape 10T), the south pole, and the north pole are arranged in that order from left to right in the direction of travel. In the following explanation, the direction from left to right in the direction of travel will be referred to as the vehicle width direction.

[0055] In the parallel arrangement pattern shown in Figure 17, the 15 sensor signals acquired simultaneously form the approximate magnetic intensity distribution curve shown in the upper part of Figure 18. In this approximate magnetic intensity distribution curve, two negative peaks corresponding to the two south pole magnetic pieces 10P and two positive peaks corresponding to the north pole magnetic piece 10P and the magnetic tape 10T (north pole) appear alternately. In the approximate magnetic gradient distribution curve (lower graph in Figure 18) obtained by applying a lateral operating filter to this approximate magnetic intensity distribution curve, two first zero-crossings ZC1 and two second zero-crossings ZC2 appear alternately.

[0056] Based solely on the magnetic intensity distribution and magnetic gradient distribution shown in Figure 18 at the moment vehicle 2 passes over the section where magnetic pieces 10P are arranged side by side, it is difficult to identify the second zero-crossing ZC2 corresponding to the magnetic tape 10T. As shown in the lower graph of Figure 18, among the first, second, and third zero-crossing ZC2s arranged in the vehicle width direction, it is impossible to determine whether the second zero-crossing ZC2 (the leftmost zero-crossing ZC2 in the figure) corresponds to the magnetic tape 10T, or whether the fourth zero-crossing ZC2 (the rightmost zero-crossing ZC2 in the figure) corresponds to the magnetic tape 10T. If the second zero-crossing ZC2 corresponding to the magnetic tape 10T cannot be identified, it becomes impossible to determine the arrangement pattern of the magnetic pieces 10P.

[0057] When four magnetic sources are arranged in a row, as in the parallel arrangement pattern in Figure 17, it is also advisable to exclude parallel arrangement patterns where the magnetic tape 10T is located at the end. In this case, for example, if we set the condition that the N-pole magnetic source corresponding to the magnetic tape 10T is not located at the end, we can determine that the second zero-crossing ZC2 on the left side of the approximate magnetic gradient distribution curve in the lower part of Figure 18 corresponds to the magnetic tape 10T. In this case, we can identify a parallel arrangement pattern in which, facing the vehicle width direction, one S-pole magnetic piece 10P is placed to the left of the magnetic tape 10T, and the S-pole magnetic piece 10P and the N-pole magnetic piece 10P are placed to the right of the magnetic tape 10T with the S-pole magnetic piece 10P facing inward.

[0058] Regarding the parallel arrangement pattern in Figure 17, the condition that the magnetic source for the N pole corresponding to the magnetic tape 10T is not located at the edge is not mandatory. It is also possible to determine the arrangement of the magnetic tape 10T in the parallel arrangement pattern in Figure 17 without setting any conditions regarding the arrangement of the magnetic tape 10T. For example, if we consider the behavior of the vehicle 2, where the lateral deviation of the vehicle 2 relative to the magnetic tape 10T has temporal continuity, and even if the lateral deviation fluctuates, the fluctuation is smooth in time, then the conditions regarding the arrangement of the magnetic tape 10T can be made unnecessary.

[0059] For example, it is advisable to calculate the lateral deviation of vehicle 2 assuming that each of the two second zero-crossings ZC2 in the lower graph of Figure 18 corresponds to the magnetic tape 10T. Then, from these two types of lateral deviations of vehicle 2, select the lateral deviation that is closer to the lateral deviation of vehicle 2 with respect to the magnetic tape 10T just before reaching the parallel arrangement point, and identify the second zero-crossing ZC2 related to that lateral deviation as corresponding to the magnetic tape 10T. In this case, the arrangement of the magnetic tape 10T and magnetic pieces 10P in the parallel arrangement pattern of Figure 17 can be determined without setting any conditions regarding the arrangement of the magnetic tape 10T in the parallel arrangement pattern.

[0060] The side-by-side arrangement in Figure 19 is a side-by-side arrangement in which one S-pole magnetic piece 10P is placed adjacent to the left side of the magnetic tape 10T in the direction of travel, and two S-pole magnetic pieces 10P are placed side-by-side to the right side of the magnetic tape 10T. In this side-by-side arrangement, the S-pole, N-pole (of the magnetic tape 10T), S-pole, and S-pole are arranged in the direction of the vehicle width.

[0061] In the case of the parallel arrangement pattern in Figure 19, the 15 sensor signals acquired simultaneously form the approximate magnetic intensity distribution curve shown in the upper part of Figure 20. In this approximate magnetic intensity distribution curve, the two adjacent S-pole magnetic pieces 10P on the right side of the magnetic tape 10T act as a single magnetic source, resulting in a large negative peak with a broad base. In the approximate magnetic gradient distribution curve (lower graph in Figure 20) obtained by applying a lateral operating filter to this approximate magnetic intensity distribution curve, the first zero-crossing ZC1 appears on both sides of the second zero-crossing ZC2. This arrangement of zero-crossings is similar to the arrangement of zero-crossings in the parallel arrangement pattern in Figure 14, which was referenced in Example 1 (see the lower graph in Figure 15).

[0062] In the approximate magnetic gradient distribution curve in the lower section of Figure 20, the second zero-crossing ZC2 corresponding to the magnetic tape 10T appears at the center position M2 in the vehicle width direction of the magnetic tape 10T, as shown in Figure 21. Also, the first zero-crossing ZC1 corresponding to the single S-pole magnetic piece 10P on the left side of the magnetic tape 10T in the direction of travel appears at the center position M1 in the vehicle width direction of the magnetic piece 10P, as shown in the same figure. The distance a between this first zero-crossing ZC1 and the second zero-crossing ZC2 corresponding to the magnetic tape 10T in the vehicle width direction is 100 mm, which is the sum of half the width of the magnetic piece 10P (50 mm) and half the width of the magnetic tape 10T (50 mm).

[0063] On the other hand, the two adjacent S-pole magnetic pieces 10P on the right side of the magnetic tape 10T in the direction of travel integrate as described above and behave as a single magnetic source centered at the adjacent point M3 of the two adjacent magnetic pieces 10P (Figure 21). In this case, in the approximate curve of the magnetic gradient distribution in the lower part of Figure 20, the first zero-crossing ZC1 corresponding to the single magnetic source appears at the adjacent point M3, which is the center of the single magnetic source. The distance b (Figure 21) between this first zero-crossing ZC1 and the second zero-crossing ZC2 corresponding to the magnetic tape 10T in the vehicle width direction is 150 mm, which is the sum of the width of the magnetic piece 10P, 100 mm, and half the width of the magnetic tape 10T, 50 mm.

[0064] In this case, since the distance b between the second zero-crossing ZC2 corresponding to the magnetic tape 10T and the first zero-crossing ZC1 is 1.5 times the width of the magnetic tape 10T and the magnetic piece 10P, it is possible to identify a configuration in which two S-pole magnetic pieces 10P are arranged side by side adjacent to the magnetic tape 10T. In this case, it is possible to identify a side-by-side arrangement pattern in which one S-pole magnetic piece 10P is on the left side of the magnetic tape 10T in the direction of travel, and two S-pole magnetic pieces 10P are on the right side.

[0065] Furthermore, the side-by-side arrangement in Figure 22 is a side-by-side arrangement in which the south pole magnetic piece 10P is placed adjacent to the left side of the magnetic tape 10T in the direction of travel, and the north pole magnetic piece 10P and the south pole magnetic piece 10P are placed adjacent to the right side of the magnetic tape 10T with the north pole magnetic piece 10P on the inside. In this side-by-side arrangement, the south pole, the north pole (of the magnetic tape 10T), the north pole (of the magnetic piece 10P), and the south pole are arranged in the direction of the vehicle width.

[0066] In the parallel arrangement pattern shown in Figure 22, the 15 sensor signals acquired simultaneously form the approximate magnetic intensity distribution curve shown in the upper part of Figure 23. In this approximate magnetic intensity distribution curve, the magnetic tape 10T and the N-pole magnetic piece 10P adjacent to its right side act as a single magnetic source, resulting in a large positive peak with a broad base. In the approximate magnetic gradient distribution curve (lower graph in Figure 23), obtained by applying a lateral operating filter to this approximate magnetic intensity distribution curve, the first zero-crossing ZC1 appears on both sides of the second zero-crossing ZC2, similar to the approximate magnetic gradient distribution curve in Figure 20.

[0067] In the lower section of the approximate magnetic gradient distribution curve in Figure 23, the first zero-crossing ZC1 corresponding to the S-pole magnetic pieces 10P at both ends in the vehicle width direction appears at the vehicle width direction center positions M4 and M6 of the corresponding magnetic pieces 10P, as shown in Figure 24. On the other hand, the second zero-crossing ZC2 corresponding to a single magnetic source formed by the integration of the N-pole magnetic tape 10T and the adjacent N-pole magnetic piece 10P appears at the adjacent point M5 between the magnetic tape 10T and the magnetic piece 10P, as shown in the same figure. This second zero-crossing ZC2 is located equidistant from the first zero-crossing ZC1 on both sides.

[0068] In the lower graph of Figure 23, the separation distance c (Figure 24) between the second zero-crossing ZC2 and the first zero-crossing ZC1 on the left side in the direction of travel is 150 mm, which is the sum of the width of the magnetic tape 10T (100 mm) and half the width of the magnetic piece 10P (50 mm). Similarly, the separation distance d (Figure 24) between the second zero-crossing ZC2 and the first zero-crossing ZC1 on the right side in the direction of travel is 150 mm, which is the sum of the width of the N-pole magnetic piece 10P (100 mm) and half the width of the S-pole magnetic piece 10P (50 mm). In this case, since both the separation distance c and the separation distance d are 1.5 times the width of the magnetic tape 10T and the magnetic piece 10P, it can be concluded that the magnetic piece 10P of the same pole is adjacent to the N-pole magnetic tape 10T and is integrated as one magnetic source of the N pole.

[0069] However, in this case, it is difficult to determine whether the magnetic tape 10T is on the right side or the left side of the integrated N-pole magnetic source in the direction of travel. In such a case, by using the lateral deviation relative to the magnetic tape 10T just before the vehicle 2 reaches the location where the magnetic pieces 10P are arranged side by side, it becomes possible to determine which side of the integrated N-pole magnetic source is the magnetic tape 10T.

[0070] It is advisable to determine the lateral deviation of vehicle 2 when assuming that the magnetic tape 10T is on the right side in the direction of travel, and the lateral deviation of vehicle 2 when assuming that the magnetic tape 10T is on the left side, among the integrated N-pole magnetic sources at the parallel installation location. Of these two lateral deviations, it is advisable to assume that the assumption relating to the lateral deviation of vehicle 2 that is closer to the lateral deviation of vehicle 2 identified just before reaching the parallel installation location is true. In the case of Figures 22 to 24, it can be estimated that the magnetic tape 10T is on the left side in the direction of travel among the integrated N-pole magnetic sources. Based on this estimation, it is possible to identify a parallel installation pattern in which one S-pole magnetic piece 10P is installed next to the magnetic tape 10T in the direction of travel, and an N-pole magnetic piece 10P and an S-pole magnetic piece 10P are installed in sequence next to the right side.

[0071] By adopting the parallel arrangement pattern of magnetic pieces 10P illustrated in this example, the number of parallel arrangement patterns can be increased, thereby increasing the types of information that can be provided to the vehicle 2 side from the parallel arrangement points of the magnetic pieces 10P. Here, in the parallel arrangement pattern of the magnetic tape 10T, which is the magnetic source, and the magnetic pieces 10P, if it is assumed that adjacent magnetic sources have different magnetic polarities, for example, as shown in Figure 17, then it becomes relatively easy to identify parallel arrangement patterns that utilize zero crossing. On the other hand, if the parallel arrangement pattern in Figure 19 is permitted, the combination of magnetic polarities of two adjacent magnetic pieces 10P can be arbitrarily chosen, thereby increasing the number of parallel arrangement patterns. If the parallel arrangement pattern in Figure 22 is permitted, the magnetic polarity of the magnetic piece 10P adjacent to the magnetic tape 10T can be arbitrarily chosen. Thus, relaxing the requirements regarding the magnetic polarity of the magnetic pieces 10P is effective in increasing the number of parallel arrangement patterns.

[0072] In this example, a configuration in which three magnetic pieces 10P are arranged side by side on a magnetic tape 10T is shown, but the number of magnetic pieces 10P arranged side by side may be two, four or more, or any number of other magnetic pieces 10P. By adopting the arrangement configuration shown in this example, it is possible to increase the variety of arrangement patterns.

[0073] The other components and effects are the same as in Example 1.

[0074] Although specific examples of the present invention have been described in detail as shown in the examples above, these examples only disclose an example of the technology covered by the claims. Needless to say, the claims should not be interpreted restrictively based on the configuration or numerical values ​​of the specific examples. The claims encompass technologies obtained by various modifications, changes, or combinations of the above examples using prior art or the knowledge of those skilled in the art. [Explanation of symbols]

[0075] 1. Magnetic detection system 10P Magnetic Piece 10T Magnetic Tape 11. Conveying System 11R route 2 vehicles 3 Magnetic Unit 33 Detection Circuit 35 Information acquisition circuit 38. Information Database (Information DB, Memory Circuit) 40 Control Units 44 Motor Units 442 Wheel speed sensor 46 Steering Unit An, A1~A15 Magnetic Sensors

Claims

1. A magnetic detection system for detecting the magnetic tape and the one or more magnetic pieces in a vehicle traveling along a path in which a magnetic tape is laid along the path and one or more individual magnetic pieces are arranged side by side on the magnetic tape, A magnetic unit is mounted on a vehicle such that multiple magnetic sensors capable of measuring the magnitude of the magnetic field acting from the road surface are arranged linearly, and the direction of this arrangement is aligned with the vehicle width direction. The system includes a detection circuit that performs a detection process for magnetically detecting the magnetic tape and the one or more magnetic pieces, The detection circuit is configured to detect the magnetic tape and each of the magnetic pieces by processing the magnetic measurement values ​​from each of the magnetic sensors of the magnetic unit, and is a magnetic detection system.

2. A magnetic detection system according to claim 1, wherein the detection circuit is configured to detect the magnetic tape and each of the magnetic pieces in locations where the magnetic pieces are arranged side by side with respect to the magnetic tape, without distinguishing between locations where the magnetic pieces are arranged side by side with respect to the magnetic tape and locations where the magnetic pieces are not arranged side by side with respect to the magnetic tape, and to detect the magnetic tape and the absence of the magnetic pieces in locations where the magnetic pieces are not arranged side by side.

3. The magnetic detection system according to claim 2, wherein the detection circuit acquires changes in the magnetic gradient in the vehicle width direction based on magnetic measurement values ​​from each of the magnetic sensors, and is configured to detect the magnetic tape and the one or more magnetic pieces according to the arrangement of a first zero-crossing where the magnetic gradient switches from a negative value to a positive value, and a second zero-crossing where the magnetic gradient switches from a positive value to a negative value.

4. The present invention relates to a memory circuit that stores various types of information by linking the arrangement pattern of one or more magnetic pieces on the magnetic tape, A magnetic detection system including an information acquisition circuit that reads from a storage circuit information to which the parallel arrangement patterns of each magnetic piece detected by the detection circuit are linked.

5. A magnetic detection system according to any one of claims 1 to 4, wherein the one or more magnetic pieces are arranged side by side such that their magnetic polarity is different from that of adjacent magnetic tapes or other magnetic pieces.

6. A method for detecting the magnetic tape and the one or more magnetic pieces by a vehicle traveling along a path in which a magnetic tape is laid along the path and one or more individual magnetic pieces are arranged side by side on the magnetic tape, The vehicle is equipped with a magnetic unit consisting of multiple magnetic sensors arranged linearly, capable of measuring the magnitude of the magnetic field acting from the road surface, and is mounted along the width of the vehicle. The process includes a detection process for magnetically detecting the magnetic tape and the one or more magnetic pieces. The detection process involves detecting the magnetic tape and each of the magnetic pieces by processing the magnetic measurement values ​​from each magnetic sensor of the magnetic unit.

7. The magnetic detection method according to claim 6, wherein the detection process does not distinguish between locations where one or more magnetic pieces are arranged side by side with respect to the magnetic tape and locations where one or more magnetic pieces are not arranged side by side with respect to the magnetic tape, and in locations where they are arranged side by side, the process is capable of detecting the magnetic tape and the one or more magnetic pieces, and in locations where they are not arranged side by side, the process is capable of detecting the magnetic tape and detecting that the magnetic pieces are not arranged side by side.

8. A magnetic detection method according to claim 7, wherein the detection process acquires a change in the magnetic gradient in the vehicle width direction based on the magnetic measurement value from each of the magnetic sensors, and detects the magnetic tape and the one or more magnetic pieces by identifying the arrangement of a first zero-crossing where the magnetic gradient switches from a negative value to a positive value, and a second zero-crossing where the magnetic gradient switches from a positive value to a negative value.

9. A magnetic detection method according to any one of claims 6 to 8, wherein the one or more magnetic pieces are arranged side by side such that their magnetic polarity is different from that of adjacent magnetic tapes or other magnetic pieces.

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