Vehicle-mounted device and determination method

Abstract

The invention provides an in-vehicle device and a determination method. The present invention improves the accuracy of correctly detecting a magnet provided on a track in a vehicle-mounted device. The permanent magnet (7) is disposed at a predetermined installation position of the rail (5) in such a manner that the surface on which different magnetic poles are arranged is the upper surface, and the different magnetic poles are positioned in the direction along the rail (5). A vehicle-mounted device (1) detects a magnetic field distribution based on a detection value of each of a plurality of magnetic sensor elements arranged in a predetermined positional relationship of a magnetic sensor unit (10). The in-vehicle device (1) performs spatial filtering processing including at least a differential element on the detected magnetic field distribution. The in-vehicle device (1) determines whether or not the installation position of the permanent magnet (7) has passed by comparing a predetermined reference magnetic field distribution with the magnetic field distribution after the spatial filtering processing.

Description

TECHNICAL FIELD

[0001] The present application relates to an in-vehicle device or the like. BACKGROUND

[0002] For a railway, a method of detecting a train position on a vehicle is gradually becoming widespread with the aim of simplifying ground equipment. As a detection method of detecting a train position on a vehicle, a method of calculating a running distance by integrating speed information of a train acquired by a tachometer generator, a pulse generator, a speed sensor, or the like, and detecting a train position is generally used. The speed information thus acquired has a high possibility of containing an error, and therefore, from the viewpoint of safety, it is necessary to periodically reset an error of a train position using other equipment for position correction such as a GNSS (Global Navigation Satellite System), an ATS (Automatic Train Stop) ground piece, or the like, in addition to a magnet for position correction provided to a track and detected by a vehicle-mounted device. In recent years, a method of detecting an absolute position by providing a magnet for position correction to a track and detecting the magnet by a vehicle-mounted device, and thereby resetting an error of a train position has been proposed (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENT

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2022-170810 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In addition, for a railway, there are many objects such as a steel bridge, a steel track, or the like, which are strongly magnetized, and a current for train control flowing in a steel track, and it is possible that false detection occurs due to the presence of such objects and the like in the vicinity of a magnet for position correction. That is, a vehicle-mounted device detects a magnetic field generated by a magnet by a magnetic sensor, but if there are magnetized objects or a current for train control flowing in a steel track, a magnetic field generated by them is also detected. Therefore, it is possible that a magnet is not detected or a magnet that does not exist is erroneously detected. This problem is not a problem only when the magnet is a magnet for position correction.

[0008] The problem to be solved by the present application is to improve the accuracy of a magnet provided to a track that can be accurately detected in a vehicle-mounted device.

[0009] SOLUTION TO THE PROBLEM

[0010] A first invention for solving the above-described problem is a vehicle-mounted device mounted on a vehicle that travels on a track on which a magnet is provided at a predetermined installation position, the vehicle-mounted device comprising:

[0011] a magnetic sensor section having a plurality of magnetic sensor elements arranged in a predetermined positional relationship to detect a generated magnetic field of the magnet when passing through the installation position; and

[0012] a processing section that determines whether the installation position has been passed based on a detection value of the magnetic sensor section,

[0013] wherein the magnet is configured to have a surface on which different magnetic poles are arranged as an upper surface, and the different magnetic poles are located in a position along a direction of the track,

[0014] the processing section has:

[0015] a detection section that detects a magnetic field distribution based on detection values of the respective magnetic sensor elements of the magnetic sensor section;

[0016] a spatial filter processing section that performs spatial filter processing including at least a differentiation element on the detected magnetic field distribution; and

[0017] a determination section that determines whether the installation position has been passed by comparing a predetermined reference magnetic field distribution with the magnetic field distribution after the spatial filter processing.

[0018] As another invention, a determination method can also be configured for determining, by a vehicle-mounted device mounted on a vehicle that travels on a track on which a magnet is provided at an installation position, whether the installation position has been passed, wherein

[0019] the vehicle-mounted device has a magnetic sensor section having a plurality of magnetic sensor elements arranged in a predetermined positional relationship to detect a generated magnetic field of the magnet when passing through the installation position,

[0020] the magnet is configured to have a surface on which different magnetic poles are arranged as an upper surface, and the different magnetic poles are located in a position along a direction of the track,

[0021] the determination method includes:

[0022] the vehicle-mounted device detects a magnetic field distribution based on detection values of the respective magnetic sensor elements of the magnetic sensor section;

[0023] the vehicle-mounted device performs spatial filter processing including at least a differentiation element on the detected magnetic field distribution; and

[0024] The in-vehicle device determines whether the installation position is passed by comparing a prescribed reference magnetic field distribution with a magnetic field distribution subjected to the spatial filtering process.

[0025] According to the first invention and the like, it is possible to improve the accuracy with which a magnet installed on a track is correctly detected in an in-vehicle device. That is, the in-vehicle device determines that the installation position of the magnet is passed by comparing a magnetic field distribution subjected to a spatial filtering process on a magnetic field distribution based on detection values of each magnetic sensor element with a prescribed reference magnetic field distribution. The magnet is arranged so that a surface on which different magnetic poles are arranged is an upper surface, and the different magnetic poles are located in a position in a direction along the track. Thus, the magnetic field distribution detected by each of a plurality of magnetic sensor elements moving in the direction along the track becomes a magnetic field distribution in which a sharp magnetic field change occurs in space at a position corresponding to the different magnetic poles.

[0026] By subjecting such a magnetic field distribution to a spatial filtering process including at least a differentiation element, it is possible to capture a sharp magnetic field change in space. For example, a magnetic field generated by a magnetized object located at a position relatively far from the magnetic sensor portion, a current flowing in a rail, or the like is detected as a magnetic field distribution in which the magnitude of the magnetic field itself can be large compared to the magnet but changes gently in space. Thus, the in-vehicle device can correctly detect the magnet while distinguishing it from other objects that generate a magnetic field, and determine whether the installation position of the magnet is passed.

[0027] The second invention is, in the above invention,

[0028] The spatial filtering process portion performs the spatial filtering process including at least a second differentiation element.

[0029] According to the second invention, it is possible to more reliably capture a sharp magnetic field change in space, and thus it is possible to further improve the detection accuracy of the magnet.

[0030] The third invention is, in the above invention,

[0031] The magnetic sensor portion has the planar magnetic sensor elements arranged in the front-rear and left-right directions of the vehicle.

[0032] According to the third invention, it is possible to detect a magnetic field generated by the magnet as a two-dimensional array of magnetic field distributions, which is suitable for spatial filtering processing.

[0033] The fourth invention is, in the above invention,

[0034] There are a plurality of kinds of magnets different in at least one of the size, the installation orientation, and the arrangement pattern of the magnetic poles,

[0035] the kind of the magnet provided at the provided position is determined for each of the provided positions at which the magnet is provided,

[0036] for the reference magnetic field distribution, there are reference magnetic field distributions for each kind of the magnet,

[0037] The determination section compares the magnetic field distribution after the spatial filtering processing by the spatial filtering processing section with each reference magnetic field distribution for the kind of the magnet, to determine the kind of the magnet provided at the passed provided position.

[0038] According to the fourth application, by previously associating the kind of the magnet with the provided position, the on-vehicle device can determine the kind of the magnet that has passed the provided position, and determine the provided position, to correct, for example, the position of the train.

[0039] The fifth application is, in the above-mentioned application,

[0040] The magnetic sensor element has a plurality of detection axes,

[0041] The detection section detects the magnetic field distribution for each of the detection axes,

[0042] for the reference magnetic field distribution, there are reference magnetic field distributions for each of the detection axes,

[0043] The determination section compares the magnetic field distribution after the spatial filtering processing by the spatial filtering processing section with each reference magnetic field distribution for the kind of the magnet, to determine the kind of the magnet provided at the passed provided position.

[0044] According to the fifth application, the magnetic field generated by the magnet is a magnetic field distribution in three-dimensional space, so that the magnetic field generated by the magnet can be more accurately detected by comparing the magnetic field distribution detected for each detection axis of the magnetic sensor element having a plurality of detection axes with the reference magnetic field distribution, to determine whether the provided position of the magnet has been passed with higher accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is an application example of the on-vehicle device.

[0046] Figure 2 is a structural example of the magnetic sensor section.

[0047] Figure 3 is an explanatory diagram of the representation method of the magnetic field distribution.

[0048] Figure 4 is an example of the kind of the permanent magnet.

[0049] Figure 5 is an example of the kind of the permanent magnet.

[0050] Figure 6It is an example of a type of permanent magnet.

[0051] Figure 7 It is an example of a type of permanent magnet.

[0052] Figure 8 It is an example of a type of permanent magnet.

[0053] Figure 9 This is an example of detecting magnetic field distribution.

[0054] Figure 10 is an example of a spatial filter coefficient.

[0055] Figure 11 is with Figure 9 An example of the magnetic field distribution after spatial filtering corresponding to the detected magnetic field distribution.

[0056] Figure 12 This is an example of detecting magnetic field distribution.

[0057] Figure 13 is with Figure 12 An example of the magnetic field distribution after spatial filtering corresponding to the detected magnetic field distribution.

[0058] Figure 14 This is a functional structure diagram of the vehicle-mounted control device.

[0059] Figure 15 This is an example of test data.

[0060] Figure 16 This is an example of setting magnet data.

[0061] Figure 17 This is a flowchart of the determination process. DETAILED DESCRIPTION

[0062] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the mode in which the present invention can be applied is not limited to the following embodiments. In addition, in the description of the accompanying drawings, the same reference numerals are used for the same elements.

[0063] [Overall structure]

[0064] Figure 1 FIG is a diagram schematically showing an application example of the vehicle-mounted device of this embodiment. Figure 1 As shown, the onboard device 1 is mounted on a railway vehicle 3 traveling on a track 5 and includes a magnetic sensor unit 10 and an onboard control device 30. A plurality of permanent magnets 7 are installed at predetermined locations on the track 5 according to their type. In this embodiment, the permanent magnets 7 are installed between the left and right rails. The type of permanent magnet 7 is determined by its size, installation orientation, and the arrangement pattern of its magnetic poles, i.e., its magnetization pattern.

[0065] The magnetic sensor section 10 is provided at the bottom of the railway vehicle 3, the bogie, i.e., at a position where the position of the permanent magnet 7 provided on the track 5 can be detected. It is preferable that the magnetic sensor section 10 be provided at a position facing the permanent magnet 7 when passing the position where the permanent magnet 7 is provided.

[0066] The on-board control device 30 calculates the running position of the railway vehicle 3 at all times by integrating the speed information obtained by a tachometer generator, a pulse generator, or the like. In the present embodiment, since the position where the permanent magnet 7 is provided is decided in advance, when the permanent magnet 7 is detected by the magnetic sensor section 10, the on-board control device 30 can correct the calculated running position using the detected position of the permanent magnet 7.

[0067] Figure 2 is a view showing an example of the configuration of the magnetic sensor section 10. In Figure 2 , a schematic plan view of the magnetic sensor section 10 as viewed from above is shown. As Figure 2 indicated, the magnetic sensor section 10 has a plurality of magnetic sensor elements 12 arranged in a planar manner facing the track 5. In Figure 2 , a magnetic sensor section 10 having a total of 16 magnetic sensor elements 12, i.e., A to P, arranged in a planar manner in four rows in the left-right direction and four rows in the front-rear direction of the railway vehicle 3 is shown. The interval between adjacent magnetic sensor elements 12 is a position where the magnetic sensor elements 12 do not overlap each other, and it is preferable that the interval between the centers of the magnetic sensor elements 12 be within 150 mm in both the left-right direction and the front-rear direction. Note that the number of magnetic sensor elements 12 and the arrangement of the magnetic sensor section 10 are not limited to this example.

[0068] The magnetic sensor element 12 is an element that detects a magnetic field and outputs a current or a voltage corresponding to the magnitude and orientation of the magnetic field as a detection value. The magnetic sensor element 12 is, for example, a Hall element, a magnetoresistance effect element (MR element), a magnetic impedance element (MI element), a flux gate sensor, or the like.

[0069] The magnetic sensor element 12 is a three-axis sensor having three detection axes (X-axis, Y-axis, and Z-axis), and is arranged so that the X-axis coincides with the front-rear direction of the railway vehicle 3, the Y-axis coincides with the left-right direction of the railway vehicle 3, and the Z-axis coincides with the up-down direction of the railway vehicle 3, respectively. The detection values of the magnetic sensor element 12 are output to the on-board control device 30. The on-board control device 30 detects the magnetic field distribution based on the detection values of the respective magnetic sensor elements 12.

[0070] Figure 3: This is a diagram illustrating a method of representing the magnetic field distribution in this embodiment. The magnetic sensor element 12 is a three-axis sensor having three detection axes, and the onboard control device 30 detects the magnetic field distribution based on the detection value of each magnetic sensor element 12 along the three detection axes. The magnetic field distribution for one detection axis is represented as a two-dimensional array with the detection value of each magnetic sensor element 12 along the detection axis as the element I (i, j). The positive and negative signs of the detection values ​​of the magnetic sensor elements 12 represent the direction of the magnetic field, and the magnitude (absolute value) represents the magnitude (intensity) of the magnetic field. The two-dimensional array corresponds to the configuration position of the magnetic sensor elements 12 in the magnetic sensor unit 10, so that the front-to-back direction (travel direction) of the railway vehicle 3 corresponds to the i direction of the two-dimensional array, and the left-to-right direction (sleeper direction) of the railway vehicle 3 corresponds to the j direction.

[0071] A plurality of types of permanent magnets 7 are arranged at predetermined installation positions on the track 5 according to their types. The type of permanent magnet 7 is determined by its size, installation direction, and arrangement pattern of the magnetic poles, i.e., the magnetization pattern. If the types of permanent magnets 7 are different, the magnetic field (generated magnetic field) generated by the permanent magnets 7 is different. Therefore, when the railway vehicle 3 passes through the installation position of the permanent magnet 7, the magnetic field distribution detected by the magnetic sensor unit 10 mounted on the railway vehicle 3 is different. Taking advantage of this situation, the on-board control device 30 determines the type of permanent magnet 7 detected based on the magnetic field distribution detected by the magnetic sensor unit 10. Then, the installation position of the permanent magnet 7 of the determined type is used to correct the driving position.

[0072] Figures 4-7 : is a diagram showing an example of the type of permanent magnet 7. Figures 4-7 As shown, the permanent magnets 7a to 7d are configured to have a substantially rectangular shape in a plan view. The permanent magnets 7a to 7d are configured as a single magnet having a magnetization pattern that varies depending on the location. Specifically, for example, they can be configured by combining a plurality of magnet pieces.

[0073] Figure 4 The magnetization pattern of the permanent magnet 7a shown is a magnetization pattern in which the magnetic poles at the diagonal positions when viewed from above are the same. Figure 4 The upper left and lower right magnetic poles on the upper surface are N poles, and the upper right and lower left magnetic poles are S poles. In other words, the magnetic poles (N pole and S pole) are arranged in different directions along the track 5 (front-back direction, X-axis direction).

[0074] A magnetic flux is generated in the permanent magnet 7 from the north pole toward the south pole. Therefore, even when the permanent magnets 7 (e.g., permanent magnets 7a) are arranged with the same magnetization pattern, if the orientations are different, the magnetic field distribution (detected magnetic field distribution) detected by the magnetic sensor unit 10 will be different. Therefore, permanent magnets 7 with the same magnetization pattern but different orientations can be treated as different types of permanent magnets 7. For example, Figure 5The magnetization pattern of the permanent magnet 7b shown is the same as that of the permanent magnet 7a, but the setting orientation in which the upper left and right lower poles are S poles and the right upper and left lower poles are N poles, i.e., the setting orientation after rotating the permanent magnet 7a by 90 degrees around the Z axis, is handled as a different kind from the permanent magnet 7a.

[0075] In addition, Figure 6 The magnetization pattern of the permanent magnet 7c shown is a magnetization pattern in which the poles are alternately the same poles in the front-rear direction (X axis direction) when viewed from above. The setting orientation of the permanent magnet 7c is the setting orientation in which the first and third poles from the front in the direction along the track (front-rear direction) are N poles and the second and fourth poles are S poles. Figure 6

[0076] In addition, Figure 7 The magnetization pattern of the permanent magnet 7d shown is the same as that of the permanent magnet 7c, but the setting orientation in which the first and third poles from the front in the direction along the track (front-rear direction) are S poles and the second and fourth poles are N poles, i.e., the setting orientation after rotating the permanent magnet 7c by 180 degrees around the Z axis, is a different kind from the permanent magnet 7c.

[0077] Further, the shape of the permanent magnet 7 is not limited to a rectangular shape when viewed from above, and can be another shape such as a circular shape. For example, it can be provided as a magnetization pattern in which different poles are arranged in concentric circular shapes as with the permanent magnet 7e shown. Figure 8

[0078] The determination of the kind of the permanent magnet 7 is performed by comparing the magnetic field distribution after the spatial filtering process prescribed for the magnetic field distribution detected by the magnetic sensor section 10 (hereinafter appropriately referred to as "detected magnetic field distribution") with a reference magnetic field distribution decided in advance in correspondence with the kind of the permanent magnet 7.

[0079] ​​The reference magnetic field distribution is a magnetic field distribution serving as a reference for determining whether the railway vehicle 3 has passed the set position of the corresponding type of permanent magnet 7. Specifically, it is determined on the basis of the magnetic field distribution after the aforementioned spatial filtering process is performed on the magnetic field distribution that can be detected by the magnetic sensor section 10 at the time when the railway vehicle 3 passes the set position of the permanent magnet 7. As for the magnetic field distribution that can be detected by the magnetic sensor section 10, for example, it can be set to the magnetic field distribution detected when the railway vehicle 3 actually runs on the track 5 after the permanent magnet 7 is set to the track 5, or it can be obtained through experiments in a laboratory, a factory, or the like, or simulation using a computer, since the magnetic field distribution detected by the magnetic sensor section 10 is determined by the relative positional relationship between the permanent magnet 7 and the magnetic sensor section 10. In addition, the magnetic sensor element 12 is a three-axis sensor, and the magnetic field distribution is detected for each detection axis, so the reference magnetic field distribution is also determined for each detection axis.

[0080] The spatial filtering process for the detected magnetic field distribution is a spatial filtering process having at least a differentiation element. More preferably, it is a spatial filtering process having a second differentiation element. The permanent magnet 7 is disposed with the surface on which different magnetic poles are arranged as the upper surface. By disposing the permanent magnet 7 like this, the magnetic field distribution detected by each magnetic sensor element 12 of the magnetic sensor section 10 facing the permanent magnet 7 becomes a so-called spatial frequency high magnetic field distribution in which the magnetic field sharply changes in space at a position corresponding to the different magnetic poles. By performing the spatial filtering process having at least a differentiation element on such a magnetic field distribution, a sharp magnetic field change can be detected. In addition, the permanent magnet 7 is disposed so that the arrangement direction of the positions at which the different magnetic poles are located is along the direction of the track 5, so when the railway vehicle 3 passes the set position of the permanent magnet 7 along the track 5, a magnetic field distribution in which the magnetic field sharply changes in space is detected as being generated by the permanent magnet 7 continuously in time.

[0081] As for the type of permanent magnet 7, the correlation coefficient between the magnetic field distribution after the detected magnetic field at the time of passing the set position of the permanent magnet 7 is spatially filtered (the filtered magnetic field distribution) and the reference magnetic field distribution corresponding to the type of permanent magnet 7 is obtained, and the type of permanent magnet 7 is determined on the basis of the obtained correlation coefficient. The magnetic field distribution is represented by the detection values of the detection axis obtained by the plurality of magnetic sensor elements 12 for the detection axis of the magnetic sensor element 12 (see FIG. 6). Figure 3 Thus, the correlation coefficient between the magnetic field distribution after the detected magnetic field distribution of the detection axis is spatially filtered (the filtered magnetic field distribution) and the reference magnetic field distribution is calculated for the detection axis. The correlation coefficient between the filtered magnetic field distribution and the reference magnetic field distribution for one detection axis is calculated as a normalized cross-correlation coefficient using the values of the elements of the filtered magnetic field distribution and the reference magnetic field distribution and according to the following formula (1).

[0082] [Num 1]

[0083]

[0084] In formula (1), "I(i, j)" is the value of the element of the filtered magnetic field distribution, "I a " is the average value of each element I(i, j) of the filtered magnetic field distribution, "T(i, j)" is the value of the element of the reference magnetic field distribution, "T a " is the average value of each element T(i, j) of the reference magnetic field distribution, "σ I " is the standard deviation of each element I(i, j) of the filtered magnetic field distribution, and "σ T " is the standard deviation of each element T(i, j) of the reference magnetic field distribution.

[0085] The correlation coefficient is a value within the range of "-1.0 to 1.0", and "1.0" indicates perfect matching. Also, in the case where the correlation coefficient for all (three) detection axes is greater than or equal to a prescribed threshold value (for example, "0.9"), it is determined that the filtered magnetic field distribution matches the reference magnetic field distribution. Further, the average or total of the correlation coefficients by detection axis can be calculated as a comprehensive correlation coefficient, and in the case where this comprehensive correlation coefficient is greater than or equal to a prescribed threshold value (for example, "0.9" if the average of the correlation coefficients is taken as the comprehensive correlation coefficient, and "2.7" if the total of the correlation coefficients is taken as the comprehensive correlation coefficient), it is determined that the filtered magnetic field distribution matches the reference magnetic field distribution. Further, in the case where the correlation coefficient is positive, it indicates that the magnetic properties are the same, in the case where the correlation coefficient is negative, it indicates that the magnetic properties are opposite, and in the case where the correlation coefficient is "-1.0", it indicates that the magnitude (absolute value) of the magnetic field is the same but the magnetic properties are opposite.

[0086] In addition, the railway vehicle 3 traveling on the track 5, after gradually approaching from the front of the setting position of the permanent magnet 7, passes through the setting position and gradually moves away from the distance. Therefore, the on-vehicle control device 30 repeatedly performs determination of whether or not the magnetic field distribution (filtered magnetic field distribution) after the spatial filtering process of the magnetic field distribution (detection magnetic field distribution) detected by the magnetic sensor section 10 matches each reference magnetic field distribution determined in accordance with the kind of the permanent magnet 7 at a prescribed time interval (for example, an interval of several m seconds or so). As a result, it is assumed that the correlation coefficient between the reference magnetic field distribution of one kind of the permanent magnet 7 gradually approaches "1.0" as the setting position of the permanent magnet 7 is approached.

[0087] Therefore, for example, when it is determined that the filtered magnetic field distribution of the detection magnetic field distribution detected in time series continuously matches a type of reference magnetic field distribution for a specified number of times or a number greater than the specified number of times, it is determined that the type of permanent magnet 7 is detected. If it is determined that the permanent magnet 7 is detected, the vehicle-mounted control device 30 next determines the timing of passing the setting position of the permanent magnet 7 to correct the driving position calculated on the vehicle. For example, the detection timing of the detection magnetic field distribution that best matches the reference magnetic field distribution determined for the detected type of permanent magnet 7 (for example, the highest correlation coefficient) is regarded as the passing timing of the setting position of the permanent magnet 7 for determination. The driving position calculated at the passing timing is corrected to the setting position of the permanent magnet 7. In addition, the setting position of the permanent magnet 7 is, for example, a position equivalent to the center of the rectangular shape of the permanent magnet 7 when viewed from above.

[0088] Figure 9 is through Figure 4 This example illustrates an example of a detected magnetic field distribution when a permanent magnet 7a of the type shown is installed. However, this example is an example in which only the magnetic field generated by the permanent magnet 7a is detected, as there are no other objects generating a magnetic field near the installation location of the permanent magnet 7a. This example is hereinafter referred to as "the detected magnetic field distribution of only the permanent magnet 7a." Figure 10 is an example of a spatial filter coefficient used in spatial filtering. Figure 11 is used Figure 10 The spatial filter coefficients shown are Figure 9 The detected magnetic field distribution shown is a magnetic field distribution after spatial filtering, that is, a filtered magnetic field distribution. This example is hereinafter referred to as the "filtered magnetic field distribution of only the permanent magnet 7a".

[0089] Figure 9 The detected magnetic field distribution shown is the magnetic field distribution detected by the magnetic sensor unit 10 having 36 magnetic sensor elements 12, which are 6 columns in the left-right direction and 6 columns in the front-back direction. Therefore, the detected magnetic field distribution is expressed as a two-dimensional array (matrix) of 6 rows and 6 columns. Moreover, as a spatial filtering process for the detected magnetic field distribution, a convolution operation is performed on the spatial filter coefficient and the detected magnetic field distribution. Here, it is assumed that a spatial filtering process including a quadratic differential element is performed, for example, the spatial filter coefficient is set to Figure 10 Therefore, the magnetic field distribution after spatial filtering is as follows: Figure 11 As shown, it becomes a two-dimensional matrix with 4 rows and 4 columns.

[0090] For comparison, Figure 12An example of a detected magnetic field distribution (detected magnetic field distribution) detected in a state in which a large current for train control is flowing in the rail in the vicinity of the setting position of the permanent magnet 7a is shown in FIG. 6. In the detected magnetic field distribution (detected magnetic field distribution) detected by the magnetic sensor section 10 mounted on the railway vehicle 3 when the railway vehicle 3 passes through the setting position of the permanent magnet 7a, a magnetic field generated by the permanent magnet 7a is superimposed on a magnetic field generated by a large current flowing in the rail in the vicinity. This example will be referred to as the "detected magnetic field distribution of the permanent magnet 7a and the large current" hereinafter. Also, Figure 13 is a magnetic field distribution after spatial filtering processing (filtered magnetic field distribution) performed by convoluting the spatial filtering coefficient shown in Figure 10 with the detected magnetic field distribution shown in Figure 12 . This example will be referred to as the "filtered magnetic field distribution of the permanent magnet 7a and the large current" hereinafter.

[0091] When the detected magnetic field distribution of only the permanent magnet 7a shown in Figure 9 is observed, it can be understood that the magnetic field changes sharply in space. For example, the matrix elements of each column of the first row (corresponding to the detected value of one magnetic sensor element 12) undergo an increase and a decrease in repeated values, and it can be said that the spatial frequency is high. In contrast, when the detected magnetic field distribution of the permanent magnet 7a and the large current shown in Figure 12 is observed, the magnetic field generated by the large current is larger in size than the magnetic field generated by the permanent magnet 7a, and dominates in the detected magnetic field distribution. Also, for this detected magnetic field distribution, it can be understood that the change in the spatial magnetic field is monotonic. For each row, the matrix elements of each column monotonically decrease, and it can be said that the spatial frequency is low. The rail through which the large current generating the dominant magnetic field is relatively far from the magnetic sensor section 10 compared to the permanent magnet 7a, and is therefore considered to be a detected magnetic field distribution in which the change in the magnetic field in space is gentle. Furthermore, Figure 9 , the correlation coefficient between the detected magnetic field distribution of the permanent magnet 7a shown in Figure 12 and the detected magnetic field distribution of the permanent magnet 7a and the large current shown in Figure 12 is approximately "0.16", which is very small, and thus it is difficult to determine the passage of the setting position of the permanent magnet 7a from the detected magnetic field distribution shown in

[0092] On the other hand, when the filtered magnetic field distribution of the permanent magnet 7a shown in Figure 11 is compared with the filtered magnetic field distribution of the permanent magnet 7a and the large current shown in Figure 13 , the arrangement of the matrix elements is similar, and the correlation coefficient is approximately "1.00", which is almost the maximum value. Thus, by comparing the filtered magnetic field distribution of the permanent magnet 7a shown in Figure 11The filtered magnetic field distribution of the permanent magnet 7a is set to the reference magnetic field distribution of the permanent magnet 7a, and even if there is another object that generates a magnetic field near the setting position of the permanent magnet 7a, it is possible to determine with high accuracy that the setting position of the permanent magnet 7a is passed.

[0093] [Functional Configuration]

[0094] Figure 14 is a block diagram showing a functional configuration of the in-vehicle control device 30. According to Figure 14 , the in-vehicle control device 30 includes an operation section 102, a display section 104, a sound output section 106, a communication section 108, a processing section 200, and a storage section 300, and can be configured as a kind of computer.

[0095] The operation section 102 is realized by, for example, a button switch, a touch panel, a keyboard, or the like, and outputs an operation signal corresponding to an operation performed to the processing section 200. The display section 104 is realized by, for example, an LCD (Liquid Crystal Display), a touch panel, or the like, and performs various displays corresponding to a display signal from the processing section 200. The sound output section 106 is realized by, for example, a speaker or the like, and performs various sound outputs corresponding to a sound signal from the processing section 200. The communication section 108 is realized by, for example, a communication device using a wire or wireless, and performs communication with an external device via a given communication network.

[0096] The processing section 200 is realized by, for example, a CPU (Central Processing Unit) or the like, and performs an instruction to each section configuring the in-vehicle control device 30, data transmission, and overall control of the in-vehicle control device 30 based on a program, data, or the like stored in the storage section 300. In addition, the processing section 200 functions as each functional block of the travel position calculation section 202, the travel position correction section 204, the detection section 206, the spatial filter processing section 208, and the determination section 210 by executing the determination program 302 stored in the storage section 300. However, each of these functional blocks can be configured as an independent arithmetic circuit by an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like.

[0097] The travel position calculating section 202 calculates the travel position of the railway vehicle 3 at all times. Specifically, for example, the travel distance from a given start position is integrated using speed information calculated from a rotation detection signal obtained by a tachometer generator, a pulse generator, or the like installed on an axle, and the travel position is calculated at all times.

[0098] The travel position correcting section 204 corrects the travel position calculated by the travel position calculating section 202 using the set position of the permanent magnet 7 of the kind determined by the determination section 210. Specifically, the timing at which the magnetic field distribution (detection magnetic field distribution) detected by the detection section 206 is matched with the reference magnetic field distribution corresponding to the set position of the permanent magnet 7 of the kind determined by the determination section 210 is set as the passing timing of the set position. Then, the travel position calculated at the passing timing is updated with the set position, and the travel position is corrected.

[0099] The detection section 206 detects a magnetic field distribution based on the detection value of each magnetic sensor element 12, for each of the plurality of detection axes possessed by the magnetic sensor elements 12 of the magnetic sensor section 10.

[0100] Specifically, the magnetic field distribution for one detection axis is expressed as a two-dimensional array having the detection value of the magnetic sensor element 12 of the detection axis as an element I(i, j). The two-dimensional array corresponds to the arrangement positions of the magnetic sensor elements 12 in the magnetic sensor section 10, with the front-rear direction (travel direction) of the railway vehicle 3 corresponding to the i direction of the two-dimensional array, and the left-right direction (crosstie direction) of the railway vehicle 3 corresponding to the j direction (see FIG. 2). Figure 3 ) The magnetic field distribution detected by the detection section 206 is accumulatively stored in a manner included in the detection data 330.

[0101] The spatial filter processing section 208 performs spatial filter processing including at least a differentiation element on the magnetic field distribution detected by the detection section 206. Alternatively, spatial filter processing including at least a second differentiation element can also be performed.

[0102] The spatial filter coefficient used in the spatial filter processing is stored as spatial filter coefficient data 320. In addition, the magnetic field distribution after the spatial filter processing by the spatial filter processing section 208 (filtered magnetic field distribution) is accumulatively stored in a manner included in the detection data 330.

[0103] The determination unit 210 determines whether the track has passed the location where the permanent magnet 7 is installed by comparing a predetermined reference magnetic field distribution with the magnetic field distribution after spatial filtering by the spatial filtering unit 208. There are multiple types of permanent magnets 7, each differing in at least one of size, orientation, and pole arrangement. The type of permanent magnet 7 installed on the track 5 is determined for each location where the permanent magnet 7 is installed, and a reference magnetic field distribution exists for each type of permanent magnet 7. The determination unit 210 compares the magnetic field distribution after spatial filtering by the spatial filtering unit 208 with each reference magnetic field distribution for each magnet type to determine the type of permanent magnet 7 installed at the location where the track has passed. Furthermore, a reference magnetic field distribution exists for each detection axis, and the determination unit 210 compares the reference magnetic field distribution for each detection axis with the magnetic field distribution for that detection axis after spatial filtering.

[0104] Specifically, the determination of whether the magnetic field distribution (filtered magnetic field distribution) detected by the detection unit 206 and spatially filtered by the spatial filter processing unit 208 matches each reference magnetic field distribution corresponding to the type of permanent magnet 7 is repeated at a predetermined time interval (for example, an interval of about several m seconds). Then, when the reference magnetic field distribution of one type of permanent magnet 7 is continuously matched at a predetermined number of times or more than a predetermined number of times, it is determined that the permanent magnet 7 of that type is detected. Whether the filtered magnetic field distribution matches the reference magnetic field distribution is determined based on the correlation coefficient calculated by formula (1) for each detection axis. In addition, the reference magnetic field distribution of the type of permanent magnet 7 is determined to be set as magnet data 310.

[0105] The storage unit 300 is implemented by a storage device such as a hard disk, ROM (Read Only Memory), or RAM (Random Access Memory). The processing unit 200 stores programs and data used to comprehensively control the onboard control device 30. The storage unit 300 is also used as a work area for the processing unit 200 to temporarily store calculation results obtained by the processing unit 200 according to various programs, input data obtained via the operation unit 102 and the communication unit 108, and the like. In this embodiment, the storage unit 300 stores a determination program 302, set magnet data 310, spatial filter coefficient data 320, and detection data 330.

[0106] Figure 15is a diagram showing an example of detection data 330. The detection data 330 is data related to the magnetic field distribution detected by the magnetic sensor section 10, and is generated each time detection is performed by the magnetic sensor section 10. In one detection data 330, the time of detection, the calculated travel position calculated by the travel position calculation section 202 at the time of detection, the X-axis detected magnetic field distribution data, the Y-axis detected magnetic field distribution data, and the Z-axis detected magnetic field distribution data which are the magnetic field distribution detected by the detection section 206, the X-axis filtered magnetic field distribution data, the Y-axis filtered magnetic field distribution data, and the Z-axis filtered magnetic field distribution data which are the magnetic field distribution after spatial filtering processing by the spatial filtering processing section 208, the correlation coefficient data, and the determination result are stored in correspondence with the detection ID. In the correlation coefficient data, the correlation coefficient between the spatial filtered magnetic field distribution and the reference magnetic field distribution corresponding to the kind, by the kind ID indicating the kind of the permanent magnet 7, calculated by the determination section 210, is stored for each detection axis. The determination result 327 stores data (kind ID) indicating the kind of the permanent magnet 7 corresponding to the reference magnetic field distribution determined by the determination section 210 to match the filtered magnetic field distribution, and the like.

[0107] Figure 16 is a diagram showing an example of setting magnet data 310. The setting magnet data 310 is data related to the permanent magnet 7 provided to the track 5, and is prepared for each kind of the permanent magnet 7. In one setting magnet data 310, the setting position data of the permanent magnet 7 of the kind, and the X-axis reference magnetic field distribution data, the Y-axis reference magnetic field distribution data, and the Z-axis reference magnetic field distribution data which are the reference magnetic field distribution for each detection axis are stored in correspondence with the kind ID.

[0108] [Flow of processing]

[0109] Figure 17 is a flowchart illustrating the flow of the determination processing performed by the on-vehicle control device 30. The processing is processing realized by executing the determination program 302 by the processing section 200, and is started, for example, before departure from the departure station.

[0110] First, the travel position calculation section 202 starts calculation of the travel position (step S1). Then, the detection section 206 determines whether a magnetic field is detected by the magnetic sensor section 10. Specifically, in a case where the magnitude of the detection value of each detection axis of each magnetic sensor element possessed by the magnetic sensor section 10, which is greater than or equal to a prescribed number of detection values, is greater than or equal to a prescribed threshold value, it is determined that a magnetic field is detected.

[0111] If the magnetic field is detected (step S3: Yes), the detection section 206 detects the magnetic field distribution per detection axis based on the detection values of the respective magnetic sensor elements 12 (step S5). Next, the spatial filter processing section 208 performs spatial filter processing on the magnetic field distribution (detection magnetic field distribution) detected per detection axis by the detection section 206 (step S7). Next, the determination section 210 calculates the correlation coefficient between the magnetic field distribution after the spatial filter processing (filtered magnetic field distribution) and the respective reference magnetic field distributions per type of permanent magnet 7 (step S9).

[0112] Then, whether the filtered magnetic field distribution matches each reference magnetic field distribution is determined based on whether the calculated correlation coefficient is greater than or equal to a prescribed threshold value. If there is a match, it is next determined whether the filtered magnetic field distribution has continuously matched the reference magnetic field distribution of the same type of permanent magnet 7 for a prescribed number of times or more. If there is a reference magnetic field distribution that has continuously matched the filtered magnetic field distribution for a prescribed number of times or more (step Sll: Yes), it is determined that the type of permanent magnet 7 that matches the reference magnetic field distribution has been detected (step S13).

[0113] Then, the travel position correction section 204 corrects the travel position using the set position of the determined type of permanent magnet 7 (step S15). Thereafter, whether to end the present processing is determined based on whether the end condition of reaching the terminal station has been satisfied, and if not (step S17: No), the same processing is repeated from step S3. If so (step S17: Yes), the present processing ends.

[0114] [Effects]

[0115] According to the present embodiment, the accuracy with which the permanent magnet 7 provided to the track 5 can be detected without error in the on-vehicle device 1 can be improved. That is, the on-vehicle device 1 determines that the set position of the permanent magnet 7 has passed by comparing the magnetic field distribution after the spatial filter processing on the magnetic field distribution based on the detection values of the respective magnetic sensor elements 12 with the prescribed reference magnetic field distribution. The permanent magnet 7 is configured so that the surface on which the different magnetic poles are aligned is the upper surface, and the different magnetic poles are located in the position in the direction along the track 5. Thus, the magnetic field distribution detected by each of the plurality of magnetic sensor elements 12 moving in the direction along the track becomes a magnetic field distribution in which a sharp change in the magnetic field occurs in space at a position corresponding to the different magnetic poles.

[0116] By performing spatial filtering processing of such a magnetic field distribution at least including a differential element, a magnetic field change sharply in space can be captured. For example, a magnetic field generated by an object magnetized at a position relatively far from the magnetic sensor portion 10, a current flowing in a rail, or the like is detected as a magnetic field distribution that can be large in size itself compared to the permanent magnet 7 but changes gently in space. Therefore, the on-vehicle device 1 can accurately detect the permanent magnet 7 while distinguishing the permanent magnet 7 from other objects generating a magnetic field and the like, and determine whether or not the setting position of the permanent magnet 7 is passed.

[0117] Furthermore, the embodiments to which the present application can be applied are not limited to the above-described embodiments, and of course can be changed appropriately without departing from the scope of the present application.

[0118] Explanation of Reference Numerals

[0119] 1: on-vehicle device; 10: magnetic sensor portion; 12: magnetic sensor element; 30: on-vehicle control device; 200: processing portion; 202: travel position calculation portion; 204: travel position correction portion; 206: detection portion; 208: spatial filtering processing portion; 210: determination portion; 300: storage portion; 302: determination program; 310: setting magnet data; 300: spatial filtering coefficient data; 320: detection data; 3: railway vehicle; 5: track; 7 (7a to 7e): permanent magnet.

Claims

1. An in-vehicle device mounted on a vehicle that travels on a track on which a magnet is provided at a predetermined set position, the in-vehicle device comprising: a magnetic sensor section having a plurality of magnetic sensor elements arranged in a prescribed positional relationship to detect a generated magnetic field of the magnet when passing through the set position; and a processing section that determines whether the set position has been passed based on a detection value of the magnetic sensor section, wherein the magnet is arranged with a surface on which different magnetic poles are aligned as an upper surface, and the different magnetic poles are located in a position along a direction of the track, the processing section has: a detection section that detects a magnetic field distribution based on the detection value of each magnetic sensor element of the magnetic sensor section; a spatial filter processing section that performs spatial filter processing including at least a differentiation element on the detected magnetic field distribution; and a determination section that determines whether the set position has been passed by comparing a prescribed reference magnetic field distribution with the magnetic field distribution after the spatial filter processing.

2. The in-vehicle device according to claim 1, wherein the spatial filter processing section performs the spatial filter processing including at least a second differentiation element.

3. The in-vehicle device according to claim 1, wherein the magnetic sensor section has the magnetic sensor elements arranged in a planar shape along front-rear and left-right directions of the vehicle. wherein 4. The in-vehicle device according to any one of claims 1 to 3, wherein there are a plurality of kinds of magnets different in at least one of size, set orientation, and arrangement pattern of magnetic poles for the magnet, the kind of the magnet provided at the track is determined for each of the set positions at which the magnet is provided, there are reference magnetic field distributions for each kind of the magnet for the reference magnetic field distribution, and the determination section compares the magnetic field distribution after the spatial filter processing by the spatial filter processing section with each reference magnetic field distribution for the kind of the magnet to determine the kind of the magnet provided at the passed set position.

5. The in-vehicle device according to any one of claims 1 to 3, wherein the magnetic sensor elements have a plurality of detection axes, the detection section detects the magnetic field distribution for each detection axis, there are reference magnetic field distributions for each detection axis for the reference magnetic field distribution, and the determination section compares the reference magnetic field distribution for each detection axis with the magnetic field distribution for the detection axis after the spatial filter processing for the detection axis.

6. A determination method for determining, by an in-vehicle device mounted on a vehicle that travels on a track on which a magnet is provided at a set position, whether the set position has been passed, wherein the in-vehicle device has a magnetic sensor section having a plurality of magnetic sensor elements arranged in a prescribed positional relationship to detect a generated magnetic field of the magnet when passing through the set position, the magnet is arranged with a surface on which different magnetic poles are aligned as an upper surface, and the different magnetic poles are located in a position along a direction of the track, the determination method comprises: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The in-vehicle device detects a magnetic field distribution based on detection values of each magnetic sensor element of the magnetic sensor section; The in-vehicle device performs spatial filtering processing including at least a differentiation element on the detected magnetic field distribution; and The in-vehicle device determines whether the setting position is passed by comparing a prescribed reference magnetic field distribution with the magnetic field distribution after the spatial filtering processing.

Images