Vehicle-mounted device

Abstract

Provided is an in-vehicle device. The invention provides a novel measuring method for measuring the running speed on the vehicle with high precision. A vehicle-mounted device (1) is provided with: a magnetic sensor unit (10) having a plurality of magnetic sensor elements (12) for detecting a magnetic field generated by the magnetism of a track (5) at positions separated from each other in the traveling direction; and a calculation unit (202) that calculates the travel speed on the basis of time-series data of the detection values of the magnetic sensor elements (12) and the relative positional relationship of the magnetic sensor elements (12).

Description

Technical Field

[0001] The invention relates to a vehicle-mounted device. Background Art

[0002] As a method for measuring the speed of a vehicle on a railway, the mainstream method is to measure the number of rotations of the wheel. This method can be implemented by a simple device, so it is convenient, but the measured speed is likely to contain errors caused by the idling and sliding of the wheel. Therefore, from the perspective of safety, it is necessary to detect the absolute position by some method to reset the error regularly. As a method for detecting the absolute position, a method of detecting ground equipment such as ground parts set on the track is generally used.

[0003] Therefore, as another method of measuring the traveling speed, for example, a method of measuring the traveling speed based on an image obtained by capturing a reference mark installed on a track with a vehicle-mounted camera has been proposed (for example, see Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-209026 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The above-mentioned method using the captured image does not include errors due to wheel spinning or sliding in the measured running speed, but has another problem of insufficient resistance to disturbances such as weather changes.

[0009] The problem to be solved by the present invention is to provide a new measurement method for measuring the driving speed on a vehicle with high accuracy.

[0010] Solutions for solving problems

[0011] A first invention is a vehicle-mounted device mounted on a vehicle traveling on a track, the vehicle-mounted device comprising:

[0012] a detection unit having a plurality of magnetic detection units for detecting a magnetic field generated by the magnetism of the rail at positions separated in the traveling direction; and

[0013] A calculation unit calculates a travel speed based on time series data of detection values ​​of the magnetic detection units and a relative positional relationship between the magnetic detection units.

[0014] According to the first invention, a new measurement method for measuring the traveling speed on a vehicle with high precision can be realized. That is, the time series data of the magnetic detection values ​​obtained by each of the multiple magnetic detection units mounted on the vehicle are roughly the same in the way they change over time, but the multiple magnetic detection units are mounted at positions separated along the traveling direction, so each magnetic detection unit produces a time offset in the detection timing. Therefore, the traveling speed can be measured based on the relative positional relationship of the magnetic detection units in the traveling direction and the time offset of the time series data of their detection values. In addition, the magnetic field is resistant to interference, so by using the magnetic detection values ​​in the magnetic field generated by the magnetism of the track, it is possible to achieve high-precision measurement of the traveling speed on the vehicle. In this way, it is possible to achieve high-precision measurement of the traveling speed on the vehicle with a structure that does not require ground equipment.

[0015] The second invention is a vehicle-mounted device as follows: in the above invention,

[0016] The detection unit has N magnetic detection units at positions separated along the travel direction, wherein N ≥ 3,

[0017] The vehicle-mounted device further includes a selection unit that selects M magnetic detection units from the N magnetic detection units, where N≥M≥2.

[0018] The calculation unit calculates the traveling speed using the time series data of the detection value of the magnetic detection unit selected by the selection unit.

[0019] According to the second invention, M magnetic detectors are selected from the N magnetic detectors included in the detector, and the traveling speed is calculated using time series data of the detection values ​​of the selected M magnetic detectors, thereby improving the measurement accuracy of the traveling speed.

[0020] The third invention is a vehicle-mounted device as follows: in the above invention,

[0021] The selection unit selects the magnetic detection unit based on a current traveling speed.

[0022] According to the third invention, the magnetic detection unit related to the detection value to be used in the calculation of the traveling speed is selected based on the current traveling speed, thereby making it possible to improve the measurement accuracy of the traveling speed.

[0023] A fourth invention is a vehicle-mounted device according to the above invention:

[0024] The selection unit selects the magnetic detection unit at a more distant position when the current traveling speed satisfies a second speed condition than when the current traveling speed satisfies a first speed condition, wherein the second speed condition is a condition faster than the first speed condition.

[0025] When the driving speed is high, the position change of each sampling interval of the magnetic detection obtained by the magnetic detection unit becomes large, so the resolution of the detection value becomes low, and the judgment error of the time offset of the time series data of the detection value of each magnetic detection unit becomes large. Therefore, by selecting the magnetic detection units at positions separated farther as the driving speed is faster as in the fourth invention, the judgment error of the time offset of the time series data of each magnetic detection unit can be reduced, and as a result, the measurement accuracy of the driving speed can be improved.

[0026] A fifth invention is a vehicle-mounted device according to the above invention:

[0027] The vehicle further comprises a track linearity detection unit for detecting the linearity of the track during travel.

[0028] The selection unit selects the magnetic detection unit based on the track linearity detected by the track linearity detection unit.

[0029] According to the fifth invention, the measurement accuracy of the traveling speed can be improved by selecting the magnetic detection unit related to the detection value to be used in the calculation of the traveling speed based on the linearity of the track during traveling.

[0030] A sixth invention is a vehicle-mounted device according to the above invention:

[0031] When the track linearity detected by the track linearity detection unit satisfies a second linearity condition, compared to a case where the track linearity detected by the track linearity detection unit satisfies a first linearity condition, the selection unit selects the magnetic detection unit at a farther separated position, wherein the first linearity condition represents a curve that satisfies a prescribed curvature condition, and the second linearity condition represents a straight line or is closer to a straight line than the first linearity condition.

[0032] When the vehicle is traveling on a curved portion of a track, the passing positions (trajectories) of each of the M magnetic detection units separated along the traveling direction are different, so the way the time series data of their detection values ​​change is different. Therefore, by selecting a magnetic detection unit at a closer position in the case of a curve with a large linear curvature of the track as in the sixth invention, the difference in the way the time series data of the detection values ​​change can be reduced, and the judgment error of their time offset can be reduced. As a result, the calculation accuracy of the traveling speed can be improved.

[0033] A seventh invention is a vehicle-mounted device according to the above invention:

[0034] The detection unit includes a plurality of groups of the magnetic detection units at positions separated along the traveling direction, each group being separated and arranged in the left-right direction of the vehicle.

[0035] The calculation section calculates the travel speed based on the time series data of each of the groups.

[0036] According to the seventh invention, the travel speed can be calculated based on the time series data of each of the plurality of groups obtained by separating and arranging the groups of the plurality of magnetic detection units at positions separated along the travel direction in the left-right direction of the vehicle. For example, the slight differences in the way the time series data of the detection values ​​between the groups change over time due to the shaking of the left-right direction of the traveling vehicle can be averaged, etc., to suppress the differences, thereby improving the accuracy of the time series data. As a result, the calculation accuracy of the travel speed can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is an application example of an in-vehicle device.

[0038] Figure 2 This is a structural example of a magnetic sensor unit.

[0039] Figure 3 This is an example of time series data of detection values ​​obtained by the magnetic sensor element.

[0040] Figure 4 This is a description of calculation of the offset amount of time series data of detection values ​​of the magnetic sensor element.

[0041] Figure 5 This is a description of calculation of the offset amount of time series data of detection values ​​of the magnetic sensor element.

[0042] Figure 6 This is an example of a selection of a combination of two magnetic sensor elements.

[0043] Figure 7 This is an example of a selection of a combination of two magnetic sensor elements.

[0044] Figure 8 This is a functional block diagram of the vehicle-mounted control device.

[0045] Fig. 9 is a flow chart of the speed measurement process. DETAILED DESCRIPTION

[0046] 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 given to the same elements.

[0047] Figure 1 FIG. 2 is a diagram schematically showing an application example of the vehicle-mounted device of the present embodiment. Figure 1As shown, the vehicle-mounted device 1 of the present embodiment is mounted on a railway vehicle 3 running on a track 5 , and includes a magnetic sensor unit 10 and a vehicle-mounted control device 30 .

[0048] The magnetic sensor unit 10 is a detection unit for detecting a magnetic field generated by the magnetism of the rail 5 , and is provided on the bottom or underframe of the railway vehicle 3 facing the rail 5 so as to be able to detect magnetism in the magnetic field generated by the magnetism of the rail 5 .

[0049] Figure 2 is a diagram showing an example of the structure of the magnetic sensor unit 10. Figure 2 FIG. 2 shows a schematic top view of the magnetic sensor unit 10 as viewed from above. Figure 2 As shown in FIG. 1 , the magnetic sensor unit 10 includes a plurality of magnetic sensor elements 12 arranged in a planar shape facing the rail 5 . Figure 2 In the example of FIG. 1 , a magnetic sensor unit 10 is shown having a total of 16 magnetic sensor elements 12 arranged in four rows in the left-right direction of the railway vehicle 3 and in four rows (=N (≥3)) in the traveling direction (front-rear direction) in a planar shape. With regard to the interval between adjacent magnetic sensor elements 12, it is preferred that the interval between the centers of the magnetic sensor elements 12 is within 150 mm in both the left-right direction and the traveling direction at positions where the magnetic sensor elements 12 do not overlap each other.

[0050] The magnetic sensor element 12 is a magnetic detection unit for detecting magnetism in a magnetic field generated around the track 5 by the magnetism of the track 5. The magnetic sensor element 12 detects magnetism and outputs a current or voltage corresponding to the magnitude and direction of the magnetism as a detection value. The magnetic sensor element 12 is, for example, a Hall element, a magnetoresistive element (MR element), a magneto-impedance element (MI element), a fluxgate sensor, etc. The detection value of the magnetic sensor element 12 is output to the vehicle-mounted control device 30.

[0051] The onboard control device 30 calculates the travel speed of the railway vehicle 3 based on the time series data of the detection values ​​of each magnetic sensor element 12 and the relative positional relationship of each magnetic sensor element 12. Specifically, the onboard control device 30 selects a combination (sensor group) of two (=M (N≥M≥2)) magnetic sensor elements 12 arranged along the travel direction of the railway vehicle 3 from the magnetic sensor elements 12 possessed by the magnetic sensor unit 10, and calculates the travel speed based on the time series data of the detection values ​​of each of the two magnetic sensor elements 12 and the arrangement interval along the travel direction.

[0052] Figure 3 is a diagram showing an example of time series data of the detection value of the magnetic sensor element 12. Figure 3In the figure, the horizontal axis is set to time, the vertical axis is set to the magnetic flux density of the magnetic sensor element 12 as the detection value, and the time series data of the magnetic flux density as the detection value of each of the two magnetic sensor elements 12 in the same time range are represented as a continuous waveform. The time on the horizontal axis is the time during driving, so it can be called the driving position. The track 5 is a ferromagnetic body and is magnetized during manufacturing, transportation, etc., but the magnetization method is not the same. Therefore, the magnetism of each part of the laid track 5 is not constant. Therefore, the time series data of the detection value of the magnetic sensor element 12 in the railway vehicle 3 traveling on the track 5 is a waveform in which the magnetic flux density changes according to time (more accurately, the driving position).

[0053] Here, the two magnetic sensor elements 12 are arranged along the travel direction of the railway vehicle 3, so the waveforms of the time series data of the detection values, that is, the magnetic flux density, are substantially the same waveforms. In addition, based on the difference (time offset) Δt between the two waveforms in the time direction and the arrangement interval d of the two magnetic sensor elements 12 along the travel direction of the railway vehicle 3, the travel speed v of the railway vehicle 3 can be calculated as shown in the following formula (1).

[0054] v=d / Δt…(1)

[0055] The time shift Δt of the magnetic flux density waveform can be obtained in any manner, but in this embodiment, it is obtained based on the correlation coefficient of the two waveforms. Figure 4 As shown, while changing the offset amount of one of the two waveforms in the time direction, the correlation coefficient between the one waveform and the other waveform is obtained, and the offset amount at which the correlation coefficient becomes maximum (peak) is obtained as the time offset Δt between the two waveforms.

[0056] In order to obtain the time offset Δt with higher accuracy, the offset at which the correlation coefficient is maximized may be obtained as the time offset Δt on a regression curve obtained by performing a regression operation on the relationship between the offset as a discrete value and the correlation coefficient. Figure 5 As shown in an example, the offset at which the correlation coefficient is the largest and the predetermined number of offsets before and after it can be selected, and the relationship between these offsets and the correlation coefficient (equivalent to Figure 5 A quadratic function regression operation based on the least squares method is performed, and the offset that maximizes the correlation coefficient is obtained in the obtained quadratic function (equivalent to the offset in Figure 5 The location is indicated by the large black circle in the figure).

[0057] The combination (sensor group) of two magnetic sensor elements 12 used for calculating the running speed of the railway vehicle 3 is selected based on the running speed of the railway vehicle 3 and the linearity of the track during running.

[0058] The vehicle-mounted control device 30 repeatedly calculates the travel speed of the railway vehicle 3 at a predetermined time interval. Therefore, a combination (sensor group) of two magnetic sensor elements 12 with a configuration interval corresponding to the current (latest) travel speed, that is, the travel speed calculated last time is selected. Specifically, the sensor group is selected in the following manner: compared to the case where the current travel speed satisfies the first speed condition, when the current travel speed satisfies the second speed condition, the magnetic sensor elements 12 at a position separated further are selected, wherein the second speed condition is a condition faster than the first speed condition. That is, when the travel speed is high, compared to the case where the travel speed is low, the magnetic sensor elements 12 that form a combination of positions separated further are selected.

[0059] Figure 6 , Figure 7 This is a diagram showing an example of selection of a combination (sensor group) of two magnetic sensor elements 12 based on the traveling speed. Figure 6 is the case where the second speed condition is satisfied, Figure 7 The first speed condition is satisfied. The second speed condition is that the travel speed is greater than or equal to a threshold speed (for example, 20 km / h), and the first speed condition is that the travel speed is less than the threshold speed.

[0060] like Figure 6 As shown, when the driving speed satisfies the second speed condition, that is, when the driving speed is high, a combination (sensor group) of magnetic sensor elements 12 separated the farthest along the driving direction is selected. Figure 6 In the example, the magnetic sensor unit 10 has four columns of magnetic sensor elements 12 arranged along the front-to-rear direction of the railway vehicle 3, and therefore, four groups ((A, M), (B, N), (C, O), (D, P)) consisting of a combination of the magnetic sensor elements 12 in the first column (the front column) and the magnetic sensor elements 12 in the fourth column (the last column) are selected.

[0061] In addition, if Figure 7 As shown, when the driving speed satisfies the first speed condition, that is, when the driving speed is low, a combination (sensor group) of two magnetic sensor elements 12 adjacent to each other along the driving direction is selected. Figure 7In the example, 4 groups ((A, E), (B, F), (C, G), (D, H)) which are combinations of magnetic sensor elements 12 in the 1st column (the front column) and magnetic sensor elements 12 in the 2nd column, 4 groups (E, I), (F, J), (G, K), (H, L)) which are combinations of magnetic sensor elements 12 in the 2nd column and magnetic sensor elements 12 in the 3rd column, and 4 groups ((I, M), (J, N), (K, O), (L, P)) which are combinations of magnetic sensor elements 12 in the 3rd column and magnetic sensor elements 12 in the 4th column (the last column) are selected, for a total of 12 groups.

[0062] Like this, when the current traveling speed is fast, a combination (sensor group) of two magnetic sensor elements 12 that are further apart in the traveling direction is selected compared to when the current traveling speed is slow. This is because the detection value obtained by the magnetic sensor element 12 is a discrete value sampled at a predetermined sampling interval. In other words, this is because, when the traveling speed is fast, the position change per sampling interval (i.e., the traveling distance per sampling interval) becomes larger, and thus the resolution of the detection value obtained by the magnetic sensor element 12 becomes lower. As a result, the time series data of the detection values ​​of the two magnetic sensor elements 12, i.e., the time difference of the waveform of the magnetic flux density, i.e., the time offset Δt (refer to Figure 3 ) becomes larger, and the error of the driving speed v (=d / Δt) calculated based on the time offset Δt becomes larger.

[0063] In addition, the vehicle-mounted control device 30 selects a combination (sensor group) of two magnetic sensor elements 12 according to the linearity of the track during travel. Specifically, compared with the case where the linearity of the track during travel satisfies the first linearity condition, the magnetic sensor element 12 at a position further apart is selected when the second linearity condition is satisfied. The first linearity condition indicates a curve that satisfies a prescribed curvature condition, and the second linearity condition indicates a straight line or a straight line that is closer than the first linearity condition. In other words, compared with the case of a curve or a straight line with a small curvature, the magnetic sensor element 12 at a closer position is selected when the track linearity has a large curvature.

[0064] For example, as the track linearity, the curvature of the driving position is greater than or equal to the threshold curvature as the first linearity condition, and the curvature of the driving position is less than the threshold curvature as the second linearity condition. Moreover, when the curvature of the driving position satisfies the first linearity condition, that is, when the track linearity during driving is a sharp curve, as Figure 7As shown in the figure, a combination (sensor group) of two magnetic sensor elements 12 adjacent to each other along the travel direction is selected. In addition, when the curvature of the travel position satisfies the second linear condition, that is, when the linearity of the track during travel is a straight line or a gentle curve, the above-mentioned condition related to the travel speed is given priority, and the combination (sensor group) of the magnetic sensor elements 12 is selected according to which of the first speed condition and the second speed condition the travel speed satisfies.

[0065] This is because, when the track during travel is a curve, the positions (trajectories) of two magnetic sensor elements 12 in actual space may be different. More specifically, when traveling on a curve, the vehicle body moves in a manner accompanied by the turning of the frame (generating a bogie angle), and thus forms a passing trajectory in space corresponding to the installation position of the magnetic sensor element 12. Therefore, the waveform shape of the time series data of the detection values ​​of the two magnetic sensor elements 12, that is, the magnetic flux density, may be different, and as a result, the time offset Δt (refer to Figure 3 ) becomes larger, and the error of the travel speed v (=d / Δt) calculated based on the time offset Δt becomes larger. Therefore, when the track linearity during travel is a curve with a curvature greater than or equal to a certain degree, a combination (sensor group) of two magnetic sensor elements 12 closer (adjacent) along the travel direction is selected to reduce the difference in the shape of the waveform of the magnetic flux density.

[0066] In this way, a combination (sensor group) of two magnetic sensor elements 12 to be used in calculating the travel speed of the railway vehicle 3 is selected from the magnetic sensor elements 12 included in the magnetic sensor unit 10. Then, for each selected combination (sensor group), the travel speed v of the railway vehicle 3 is calculated according to the above formula (1) based on the time offset Δt of the waveform of the magnetic flux density, which is the time series data of the detection values ​​of the two magnetic sensor elements 12, and the arrangement interval d of the two magnetic sensor elements 12 along the travel direction of the railway vehicle 3 (refer to Figure 3 Then, a predetermined statistical operation (for example, calculation of an average value) is performed on the travel speed calculated for each combination of two magnetic sensor elements 12 (sensor group) to finally determine the travel speed.

[0067] In addition, when calculating the travel speed, in the present embodiment, a plurality of combinations are selected as the combinations of the magnetic sensor elements 12, but the arrangement interval d of the two magnetic sensor elements 12 along the travel direction of the railway vehicle 3 in the selected combinations is the same in any combination. Therefore, the time offset Δt of the waveform of the magnetic flux density may be obtained for each of the selected combinations (sensor groups) of the two magnetic sensor elements 12, and the time offset Δt obtained by performing a predetermined statistical operation (e.g., calculating the average value, calculating the median) on these time offsets Δt is set as the final time offset Δt determined as the magnetic sensor unit 10, and the travel speed is calculated using the time offset Δt.

[0068] Alternatively, the magnetic sensor elements 12 of each row arranged in the left-right direction in the magnetic sensor unit 10 (in Figure 2 In the example, 4) are set as 1 group, and based on the Figure 2 In this case, the time series data of the detection values ​​of one group is determined based on the time series data of the magnetic sensor elements 12 constituting the group (for example, set as an average value). For example, in Figure 2 In the above, the group of magnetic sensor elements 12 of A, E, I, and M is set as the first group and the group of magnetic sensor elements 12 of D, H, L, and P is set as the second group to select these groups. Then, the time series data as the first group is determined based on the time series data of the detection values ​​of the magnetic sensor elements 12 of A, E, I, and M. Similarly, the time series data as the second group is determined based on the time series data of the detection values ​​of the magnetic sensor elements 12 of D, H, L, and P. Next, the time offset Δt is determined based on the time series data of the first group and the time series data of the second group, and the driving speed is calculated using the time offset Δt.

[0069] [Functional structure]

[0070] Figure 8 is a block diagram showing the functional structure of the vehicle-mounted control device 30. Figure 8 The vehicle-mounted control device 30 includes an operation unit 102, a display unit 104, a sound output unit 106, a communication unit 108, a processing unit 200, and a storage unit 300, and can be configured as a computer.

[0071] The operation unit 102 is implemented by an input device such as a button switch, a touch panel, or a keyboard, and outputs an operation signal corresponding to the completed operation to the processing unit 200. The display unit 104 is implemented by a display device such as an LCD (Liquid Crystal Display) or a touch panel, and performs various displays corresponding to the display signal from the processing unit 200. The sound output unit 106 is implemented by a sound output device such as a speaker, and performs various sound outputs corresponding to the sound signal from the processing unit 200. The communication unit 108 is implemented by a wired or wireless communication device, and communicates with an external device via a given communication network.

[0072] The processing unit 200 is implemented by a computing device such as a CPU (Central Processing Unit), and performs instructions and data transmission to each unit constituting the vehicle-mounted control device 30 based on the program and data stored in the storage unit 300, thereby performing overall control of the vehicle-mounted control device 30. In addition, the processing unit 200 functions as each functional block of the calculation unit 202, the selection unit 204, and the track linearity detection unit 206 by executing the speed measurement program 302 stored in the storage unit 300. However, these functional blocks can also be configured as independent computing circuits by ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc.

[0073] The calculation unit 202 calculates the travel speed based on the time series data of the detection values ​​of the magnetic sensor elements 12 and the relative positional relationship of the magnetic sensor elements 12. The travel speed is calculated using the time series data of the detection values ​​of the magnetic sensor elements 12 selected by the selection unit 204.

[0074] Specifically, the calculation of the travel speed is repeated at a predetermined time interval. In one calculation of the travel speed, for each combination of the two magnetic sensor elements 12 (sensor group) selected by the selection unit 204, the travel speed v of the railway vehicle 3 is calculated according to the above formula (1) based on the difference in the time direction of the waveform of the magnetic flux density, which is the time series data of the detection values ​​of the two magnetic sensor elements 12, and the arrangement interval d of the two magnetic sensor elements 12 along the travel direction of the railway vehicle 3. Then, a predetermined statistical operation (for example, calculation of the average value) is performed on the travel speed calculated for each combination of the two magnetic sensor elements 12 (sensor group) to finally determine the travel speed.

[0075] The time series data of the detection value of the magnetic sensor element 12 can be extracted from the detection data 320. The detection data 320 is data obtained by accumulating and storing the value of the magnetic flux density as the detection value for each magnetic sensor element 12 possessed by the magnetic sensor unit 10 in correspondence with the detection time. In addition, the configuration interval d of the magnetic sensor element 12 can be obtained from the magnetic sensor unit configuration data 310. The magnetic sensor unit configuration data 310 is data that specifies the configuration (relative positional relationship of the front, back, left, and right, configuration interval, etc.) of the magnetic sensor element 12 possessed by the magnetic sensor unit 10. In addition, the driving speed calculated by the calculation unit 202 is accumulated and stored as the speed data 322 in correspondence with the calculation time.

[0076] The selection unit 204 selects M (N≥M≥2) magnetic sensor elements 12 from the N (N≥2) magnetic sensor elements 12 that the magnetic sensor unit 10 as the detection unit has at positions separated in the traveling direction. In addition, the selection unit 204 selects the magnetic sensor elements 12 based on the current traveling speed. For example, compared to the case where the current traveling speed satisfies the second speed condition, the magnetic sensor element 12 at a position separated further is selected, wherein the second speed condition is a condition faster than the first speed condition. In addition, the selection unit 204 selects the magnetic sensor element 12 based on the track linearity detected by the track linearity detection unit 206. For example, compared to the case where the track linearity detected by the track linearity detection unit 206 satisfies the first linearity condition, the magnetic sensor element 12 at a position separated further is selected when the track linearity detected by the track linearity detection unit 206 satisfies the second linearity condition, wherein the first linearity condition indicates that it is a curve that satisfies a prescribed curvature condition, and the second linearity condition indicates that it is a straight line or closer to a straight line than the first linearity condition.

[0077] Specifically, the second speed condition is that the driving speed is greater than or equal to the threshold speed, and the first speed condition is that the driving speed is less than the threshold speed. Moreover, when the driving speed satisfies the second speed condition, that is, when the driving speed is high, a combination (sensor group) of magnetic sensor elements 12 separated the farthest along the driving direction is selected. In addition, when the driving speed satisfies the first speed condition, that is, when the driving speed is low, a combination (sensor group) of two magnetic sensor elements 12 adjacent to each other along the driving direction is selected. The calculation unit 202 repeatedly calculates the driving speed at a prescribed time interval, and sets the latest driving speed (more specifically, the driving speed calculated last time) calculated by the calculation unit 202 as the current driving speed. In addition, the threshold speed that becomes the first speed condition and the second speed condition is specified as the speed condition data 312.

[0078] In addition, as track linearity, the curvature of the driving position is greater than or equal to the threshold curvature as the first linear condition, and the curvature of the driving position is less than the threshold curvature as the second linear condition. Moreover, when the curvature of the driving position satisfies the first linear condition, that is, when the track linearity during driving is a curve with a relatively sharp bend, a combination (sensor group) of two magnetic sensor elements 12 adjacent to each other along the driving direction is selected. In addition, when the curvature of the driving position satisfies the second linear condition, that is, when the track linearity during driving is a straight line or a curve with a relatively gentle bend, the above-mentioned conditions related to the driving speed are given priority, and the combination (sensor group) of the magnetic sensor elements 12 is selected according to which of the first speed condition and the second speed condition the driving speed satisfies. The threshold curvatures that become the first linear condition and the second linear condition are specified as linear condition data 314.

[0079] The track linearity detection unit 206 detects the linearity of the track during driving. Specifically, the curvature of the track is detected as the track linearity. Regarding the curvature of the track, for example, a database that corresponds the position (the position on the track represented by the mileage) and the curvature may be prepared / stored in advance to obtain the curvature corresponding to the current driving position. Alternatively, a geomagnetic sensor for measuring the curvature may be additionally mounted, and the curvature of the track may be estimated based on the change in the azimuth per unit time along the driving direction obtained from the detection value of the geomagnetic sensor. Alternatively, the curvature of the track may be estimated based on the change in the azimuth of the geomagnetic field using the magnetic sensor element 12.

[0080] Back to Figure 8 The storage unit 300 is implemented by a storage device such as a hard disk, ROM (Read Only Memory), RAM (Random Access Memory), etc., and stores programs and data used by the processing unit 200 to integrally control the vehicle-mounted control device 30, and is used as an operating area of ​​the processing unit 200 to temporarily store calculation results obtained by the processing unit 200 according to various programs, input data via the operation unit 102 and the communication unit 108, etc.

[0081] In the present embodiment, the storage unit 300 stores a speed measurement program 302 , magnetic sensor unit configuration data 310 , speed condition data 312 , linear condition data 314 , detection data 320 , and speed data 322 .

[0082] [Processing flow]

[0083] Fig. 92 is a flowchart for explaining the flow of the traveling speed calculation process performed by the vehicle-mounted control device 30. This process is implemented by the processing unit 200 executing the speed measurement program 302, and is started, for example, before departure from the starting station.

[0084] First, the selection unit 204 selects a combination (sensor group) of two magnetic sensor elements 12 to be used in the calculation of the driving speed. That is, it is determined whether the current driving speed is high speed, that is, whether the second speed condition is satisfied. If the current driving speed is high speed (satisfies the second speed condition) (step S1: "Yes"), then the track linearity detection unit 206 detects the track linearity during driving (step S3). Next, the selection unit 204 determines whether the detected track linearity is a straight line or a relatively gentle curve, that is, whether the second curvature condition is satisfied.

[0085] If the track linearity is a straight line or a relatively gentle curve (satisfying the second curvature condition) (step S5: "Yes"), the selection unit 204 selects a combination of magnetic sensor elements 12 (sensor group) separated along the driving direction from the magnetic sensor elements 12 possessed by the magnetic sensor unit 10 (step S7). On the other hand, if the track linearity is neither a straight line nor a relatively gentle curve (does not satisfy the second curvature condition. It is a curve with a relatively sharp curve) (step S5: "No"), or the current driving speed is not high (does not satisfy the second speed condition. It is low speed) (step S1: "No"), the selection unit 204 selects a combination of magnetic sensor elements 12 (sensor group) adjacent to each other along the driving direction from the magnetic sensor elements 12 possessed by the magnetic sensor unit 10 (step S9).

[0086] Next, the calculation unit 202 calculates the running speed using the selected combination (sensor group) of the magnetic sensor elements 12 (step S11 ), and then adds the calculated running speed to the speed data 322 in correspondence with the calculation time, thereby updating the speed data 322 (step S13 ).

[0087] After that, it is determined whether the processing is finished by satisfying the finishing condition such as arrival at the terminal station. If it is not finished (step S15: No), the process returns to step S1 and the same processing is repeated. If it is finished (step S15: Yes), the processing is finished.

[0088] [Effects]

[0089] According to the present embodiment, a new measurement method for measuring the travel speed on the vehicle with high precision can be realized. That is, the time series data of the magnetic detection values ​​obtained by each magnetic sensor element 12 of the magnetic sensor unit 10 mounted on the railway vehicle 3 is roughly the same in the way it changes over time, but because it is mounted at positions separated along the travel direction, each magnetic sensor element 12 produces a time offset in the detection timing. Therefore, the travel speed can be measured based on the relative position relationship of the magnetic sensor element 12 in the travel direction and the time offset of the time series data of its detection value. In addition, the magnetic field is resistant to interference, so by using the magnetic detection value in the magnetic field generated by the magnetism of the track 5, the travel speed can be measured with high precision. In this way, the travel speed measurement performed on the vehicle with high precision can be realized with a structure that does not require ground equipment.

[0090] Furthermore, it is needless to say that the embodiment to which the present invention can be applied is not limited to the above-described embodiment, and can be appropriately modified within the scope not departing from the gist of the present invention.

[0091] (A) Structure of the magnetic sensor unit

[0092] In the above-mentioned embodiment, the magnetic sensor unit 10 as the detection unit has a total of 16 magnetic sensor elements 12 (see FIG. 1 ) arranged in four rows in the left-right direction of the railway vehicle 3 and in four rows (=N (≥3)) in the travel direction (front-back direction) in a planar shape. Figure 2 ), but the arrangement and number of the magnetic sensor elements 12 of the magnetic sensor unit 10 are not limited thereto. It is also possible to configure a total of 4 magnetic sensor elements 12 arranged in two rows along the left and right directions of the railway vehicle 3 and in two rows along the traveling direction (front and rear direction) in a planar shape. It is also possible to reduce the number of magnetic sensor elements 12 arranged according to the limitation of the installation space, the limitation of cost, etc., and constitute the magnetic sensor unit 10 by at least 2 magnetic sensor elements 12. In this case, it is set as follows: the magnetic sensor elements 12 are arranged separately at least along the traveling direction (front and rear direction).

[0093] (B) Selection of a combination of two magnetic sensor elements 12 (sensor group)

[0094] In the above-mentioned embodiment, the combination (sensor group) of two magnetic sensor elements 12 to be used in calculating the traveling speed of the railway vehicle 3 is selected based on both the traveling speed of the railway vehicle 3 and the linearity of the track during travel, but it may be selected based on only one of them.

[0095] For example, when selecting based only on the linearity of the track during travel, the selection can be made as follows. That is, if the curvature of the travel position satisfies the first linearity condition, that is, the linearity of the travel track is a curve with a relatively sharp bend, a combination (sensor group) of two magnetic sensor elements 12 adjacent to each other along the travel direction is selected (see Figure 7 On the other hand, if the curvature of the driving position satisfies the second linear condition, that is, the linearity of the track during driving is a straight line or a relatively gentle curve, a combination (sensor group) of two magnetic sensor elements 12 separated further in the driving direction is selected (refer to Figure 6 ).

[0096] (C) Speed ​​conditions and linear conditions

[0097] In addition, in the above-mentioned embodiment, two levels of conditions are set, such as setting the first speed condition and the second speed condition with the threshold speed as the boundary as the speed condition, and setting the first curvature condition and the second curvature condition with the threshold curvature as the boundary as the linear condition, but it can also be set to three or more levels of conditions.

[0098] For example, as the speed condition, three levels of conditions are set, wherein, in addition to the first speed condition corresponding to the low speed and the second speed condition corresponding to the high speed, the third speed condition corresponding to the medium speed is also included. Furthermore, when the third speed condition is satisfied, a combination (sensor group) of magnetic sensor elements 12 separated to a moderate degree, a combination (sensor group) of magnetic sensor elements 12 in the first column (the front column) and magnetic sensor elements 12 in the third column, and a combination (sensor group) of magnetic sensor elements 12 in the second column and magnetic sensor elements 12 in the fourth column (the last column) are selected (refer to Figure 6 , Figure 7 ). In addition, the curvature condition can also be set to three levels of conditions, wherein, in addition to the first curvature condition corresponding to a straight line and the second curvature condition corresponding to a sharp curve, the third curvature condition corresponding to a gentle curve between the straight line and the sharp curve is also included.

[0099] (D) Magnetic detection

[0100] Magnetic markers (permanent magnets) may be provided on the track 5 at locations where the track 5 is not magnetized or is magnetized but at a weak degree, such as between the left and right tracks 5. Furthermore, when the location of the magnetic marker is known, the magnetic marker can be used for position correction on the vehicle by detecting the magnetic marker.

[0101] Description of Reference Numerals

[0102] 1: vehicle-mounted device; 10: magnetic sensor unit; 12: magnetic sensor element; 30: vehicle-mounted control device; 200: processing unit; 202: calculation unit; 204: selection unit; 206: track linear detection unit; 300: storage unit; 302: speed measurement program; 310: magnetic sensor unit configuration data; 312: speed condition data; 314: linear condition data; 320: detection data; 322: speed data; 3: railway vehicle; 5: track.

Claims

1. A vehicle-mounted device, mounted on a vehicle traveling on a track, the vehicle-mounted device comprising: a detection unit having a plurality of magnetic detection units for detecting a magnetic field generated by the magnetism of the rail at positions separated in the traveling direction; and A calculation unit calculates a travel speed based on time series data of detection values ​​of the magnetic detection units and a relative positional relationship between the magnetic detection units.

2. The vehicle-mounted device according to claim 1, wherein: The detection unit has N magnetic detection units at positions separated along the travel direction, wherein N ≥ 3, The vehicle-mounted device further includes a selection unit that selects M magnetic detection units from the N magnetic detection units, where N≥M≥2. The calculation unit calculates the traveling speed using the time series data of the detection value of the magnetic detection unit selected by the selection unit.

3. The vehicle-mounted device according to claim 2, wherein: The selection unit selects the magnetic detection unit based on a current traveling speed.

4. The vehicle-mounted device according to claim 3, wherein: The selection unit selects the magnetic detection unit at a more distant position when the current traveling speed satisfies a second speed condition than when the current traveling speed satisfies a first speed condition, wherein the second speed condition is a condition faster than the first speed condition.

5. The vehicle-mounted device according to claim 2, wherein: The vehicle further comprises a track linearity detection unit for detecting the linearity of the track during travel. The selection unit selects the magnetic detection unit based on the track linearity detected by the track linearity detection unit.

6. The vehicle-mounted device according to claim 5, wherein: When the track linearity detected by the track linearity detection unit satisfies a second linearity condition, compared to a case where the track linearity detected by the track linearity detection unit satisfies a first linearity condition, the selection unit selects the magnetic detection unit at a farther separated position, wherein the first linearity condition represents a curve that satisfies a prescribed curvature condition, and the second linearity condition represents a straight line or is closer to a straight line than the first linearity condition.

7. The vehicle-mounted device according to any one of claims 1 to 6, wherein: The detection unit includes a plurality of groups of the magnetic detection units at positions separated along the traveling direction, each group being separated and arranged in the left-right direction of the vehicle. The calculation section calculates the travel speed based on the time series data of each of the groups.

Images