On-vehicle device

Abstract

To provide a novel highly accurate measurement method for driving speed on a vehicle.SOLUTION: An on-vehicle device 1 comprises, at a position separated in a traveling direction, a magnetic sensor unit 10 that includes multiple magnetic sensor elements 12 for detecting magnetic field generated by magnetism on a rail 5, and a calculation unit that calculates driving speed on the basis of time series data of detection values of the magnetic sensor elements 12 and the relative positional relationship among the magnetic sensor elements 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an on-board device. [Background technology]

[0002] The mainstream method for measuring on-board railway speed is to measure the number of wheel rotations. This method is highly convenient because it can be implemented with simple equipment, but the measured speed is likely to include errors due to wheel slippage and skidding. For this reason, from a safety perspective, it is necessary to detect the absolute position in some way and periodically reset the errors. The most common method for detecting absolute position is to detect ground equipment such as ground coils installed on the track.

[0003] As such, other methods for measuring the running speed have been proposed, such as a method for measuring the running speed from an image of a reference mark provided on the track captured by an on-board camera (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-209026 A Summary of the Invention [Problem to be solved by the invention]

[0005] The method of using the above-mentioned photographed images does not include errors due to wheel spin or skidding in the measured traveling speed, but has another problem in that it is not sufficiently resistant to disturbances such as changes in weather.

[0006] The problem to be solved by the present invention is to propose a new method for measuring traveling speed on a vehicle with high accuracy. [Means for solving the problem]

[0007] The first invention for solving the above problem is: An on-board device mounted on a vehicle running on a rail, A detection unit (e.g., magnetic sensor unit 10 in FIG. 8) having a plurality of magnetic detection units (e.g., magnetic sensor elements 12 in FIG. 2) at positions spaced apart in the running direction for detecting a magnetic field generated by the magnetism of the rail; A calculation unit (e.g., the calculation unit 202 in FIG. 8 ) that calculates a traveling speed based on time-series data of the detection values ​​of the magnetic detection units and the relative positional relationship of each of the magnetic detection units; It is an on-board device equipped with the above.

[0008] According to the first invention, a new method for measuring traveling speed on a train with high accuracy can be realized. That is, the time series data of the magnetic detection values ​​by each of the multiple magnetic detection units mounted on the train changes almost the same over time, but since the magnetic detection units are mounted at positions apart in the traveling direction, a time lag occurs in the detection timing for each magnetic detection unit. Therefore, the traveling speed can be measured from the relative positional relationship in the traveling direction of the magnetic detection units and the time lag of the time series data of the detection values. In addition, since the magnetic field is resistant to external disturbances, a highly accurate measurement of traveling speed can be realized by using the magnetic detection value in the magnetic field generated by the magnetism of the rail. In this way, a highly accurate measurement of traveling speed on a train can be realized with a configuration that does not require ground equipment.

[0009] The second invention is the above-mentioned invention, The detection unit has N (N≧3) magnetic detection units at positions spaced apart in the traveling direction, A selection unit (e.g., the selection unit 204 in FIG. 8 ) that selects M magnetic detection units (N≧M≧2) from the N magnetic detection units; Further comprising: The calculation unit calculates a traveling speed by using time series data of the detection value of the magnetic detection unit selected by the selection unit. It is an on-board device.

[0010] According to the second invention, it is possible to improve the measurement accuracy of the running speed by selecting M magnetic detection units from the N magnetic detection units possessed by the detection unit and calculating the running speed using time series data of the detection values ​​of the selected M magnetic detection units.

[0011] The third invention is the above-mentioned invention, The selection unit selects the magnetic detection unit based on a current running speed. It is an on-board device.

[0012] According to the third aspect of the present invention, the magnetic detection unit associated with the detection value used for calculating the traveling speed is selected based on the current traveling speed, thereby making it possible to improve the measurement speed of the traveling speed.

[0013] The fourth aspect of the present invention is the above-mentioned invention, the selection unit selects the magnetic detection unit located farther away when the current traveling speed satisfies a second speed condition, which is a condition faster than the first speed condition, than when the current traveling speed satisfies the first speed condition. It is an on-board device.

[0014] When the traveling speed is high, the position change per sampling interval of magnetic detection by the magnetic detection unit becomes large, resulting in a low resolution of the detection value and a large error in determining the time shift of the time series data of the detection values ​​of each magnetic detection unit. Therefore, as in the fourth invention, by selecting magnetic detection units located farther apart as the traveling speed increases, the error in determining the time shift of the time series data of each magnetic detection unit can be reduced, and as a result, the measurement accuracy of the traveling speed can be improved.

[0015] The fifth invention is the above-mentioned invention, A rail linearity detection unit (e.g., the rail linearity detection unit 206 in FIG. 8 ) that detects the rail linearity during travel; Further comprising: The selection unit selects the magnetic detection unit based on the rail alignment detected by the rail alignment detection unit. It is an on-board device.

[0016] According to the fifth aspect of the present invention, the magnetic detection unit associated with the detection value used for calculating the traveling speed is selected based on the rail alignment during traveling, thereby making it possible to improve the measurement accuracy of the traveling speed.

[0017] The sixth aspect of the present invention is the above-mentioned invention, the selection unit selects the magnetic detection unit located farther away when the rail linearity detected by the rail linearity detection unit satisfies a second linearity condition indicating that the rail linearity detected by the rail linearity detection unit is a curve satisfying a predetermined curvature condition, the second linearity condition indicating that the rail linearity is closer to a straight line or is a straight line than the first linearity condition. It is an on-board device.

[0018] When a vehicle travels on a curved section of rails, the M magnetic detection units located apart in the traveling direction pass through different positions (trajectories) and this causes differences in how the time-series data of the detection values ​​changes. For this reason, in the case of a curve with a large curvature of the rail profile, as in the sixth invention, by selecting magnetic detection units located closer to the curve, the difference in how the time-series data of the detection values ​​changes can be reduced, and the determination error due to the time difference can be reduced. As a result, the calculation accuracy of the traveling speed can be improved.

[0019] The seventh aspect of the present invention is the above-mentioned invention, the magnetic detection unit has magnetic sensor elements arranged apart in a left-right direction of the vehicle, a data determination unit that determines time-series data of detection values ​​of the magnetic detection unit based on time-series data of detection values ​​of the magnetic sensor elements that constitute the magnetic detection unit; The on-board device further comprises:

[0020] According to the seventh aspect of the present invention, based on the time series data of the detection values ​​of the magnetic sensor elements arranged apart in the left-right direction constituting the magnetic detection unit, the time series data of the detection values ​​of the magnetic detection unit can be determined. For example, slight differences in the way the time series data of the detection values ​​between the magnetic sensor elements changes over time due to the left-right rocking of the vehicle while traveling can be suppressed by averaging, thereby improving the accuracy of the time series data of the detection values ​​of the magnetic sensor unit. As a result, the accuracy of calculating the traveling speed can be improved. [Brief description of the drawings]

[0021] [Figure 1] An example of the application of on-board equipment. [Diagram 2] 3 shows an example of the configuration of a magnetic sensor unit. [Diagram 3] 4 is an example of time-series data of values ​​detected by a magnetic sensor element. [Figure 4] 5 is a diagram illustrating how to calculate the deviation amount of time-series data of the detection value of the magnetic sensor element. [Diagram 5] 5 is a diagram illustrating how to calculate the deviation amount of time-series data of the detection value of the magnetic sensor element. [Figure 6] An example of selecting a combination of two magnetic sensor elements. [Figure 7] An example of selecting a combination of two magnetic sensor elements. [Figure 8] Functional configuration diagram of the on-board control device. [Figure 9] 13 is a flowchart of a speed measurement process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the form to which the present invention can be applied is not limited to the following embodiments. In addition, in the description of the drawings, the same elements are given the same reference numerals.

[0023] Fig. 1 is a schematic diagram showing an application example of the on-board device of the present embodiment. As shown in Fig. 1, the on-board device 1 of the present embodiment is mounted on a railway vehicle 3 running on a rail 5, and includes a magnetic sensor unit 10 and an on-board control device 30.

[0024] The magnetic sensor unit 10 is a detection unit for detecting the magnetic field generated by the magnetism of the rail 5, and is provided on the bottom or bogie of the railway vehicle 3 facing the rail 5 so as to be able to detect the magnetic field in the magnetic field generated by the magnetism of the rail 5.

[0025] FIG. 2 is a diagram showing an example of the configuration of the magnetic sensor unit 10. FIG. 2 shows a schematic plan view of the magnetic sensor unit 10 seen from above. As shown in FIG. 2, the magnetic sensor unit 10 has a plurality of magnetic sensor elements 12 arranged in a plane facing the rail 5. The example of FIG. 2 shows the magnetic sensor unit 10 having a total of 16 magnetic sensor elements 12 arranged in a plane, 4 rows in the left-right direction of the railway vehicle 3 and 4 rows (=N (≧3) pieces) in the running direction (front-rear direction). The interval between adjacent magnetic sensor elements 12 is such that 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 is within 150 mm in both the left-right direction and the running direction.

[0026] The magnetic sensor element 12 is a magnetic detection unit for detecting magnetism in a magnetic field generated around the rail 5 by the magnetism of the rail 5, and is an element that detects magnetism and outputs a current or voltage according to the magnitude and direction of the magnetism 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, etc. The detection value of the magnetic sensor element 12 is output to the on-board control device 30.

[0027] The on-board control device 30 calculates the running 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 on-board control device 30 selects a combination (sensor set) of two (=M (N≧M≧2)) magnetic sensor elements 12 lined up along the running direction of the railway vehicle 3 from among the magnetic sensor elements 12 possessed by the magnetic sensor unit 10, and calculates the running 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 running direction.

[0028] FIG. 3 is a diagram showing an example of time series data of the detection values ​​of the magnetic sensor elements 12. In FIG. 3, the horizontal axis represents time and the vertical axis represents the magnetic flux density, which is the detection value of the magnetic sensor elements 12, and the time series data of the magnetic flux density, which is the detection value of each of the two magnetic sensor elements 12 in the same time range, is shown as a continuous waveform. The time on the horizontal axis is the time during travel, and can therefore be called the travel position. The rails 5 are ferromagnetic and are magnetized during manufacture, transportation, and the like, but the form of magnetization is not uniform. Therefore, the magnetism at each point of the laid rails 5 is not constant. Therefore, the time series data of the detection values ​​of the magnetic sensor elements 12 in the railway vehicle 3 traveling on the rails 5 is a waveform in which the magnetic flux density changes depending on time (more precisely, the travel position).

[0029] Here, since the two magnetic sensor elements 12 are arranged along the running direction of the railway vehicle 3, the waveforms of the magnetic flux density, which is the time series data of the detected values, are approximately the same waveform. Then, from the difference (time shift) Δt between the two waveforms in the time direction and the arrangement interval d of the two magnetic sensor elements 12 along the running direction of the railway vehicle 3, the running speed v of the railway vehicle 3 can be calculated as shown in the following formula (1). v = d / Δt (1)

[0030] The time shift Δt between the magnetic flux density waveforms may be calculated in any manner, but in this embodiment, it is calculated from the correlation coefficient between the two waveforms. That is, as shown in Fig. 4, while changing the amount of shift of one of the two waveforms in the time direction, the correlation coefficient between the one waveform and the other waveform is calculated, and the amount of shift at which the correlation coefficient becomes maximum (peak) is calculated as the time shift Δt between the two waveforms.

[0031] In order to obtain the time lag Δt with higher accuracy, the shift amount at which the correlation coefficient is maximum in the regression curve obtained by performing regression calculation on the relationship between the shift amount, which is a discrete value, and the correlation coefficient may be obtained as the time lag Δt. For example, as shown in an example in Fig. 5, the shift amount at which the correlation coefficient is maximum and a predetermined number of shift amounts before and after it are selected, and regression calculation of a quadratic function by the least squares method or the like is performed on the relationship between these shift amounts and the correlation coefficient (corresponding to the positions indicated by the small black circles in Fig. 5), and the shift amount at which the correlation coefficient is maximum in the obtained quadratic function (corresponding to the positions indicated by the large black circles in Fig. 5) can be obtained.

[0032] The combination (sensor set) of two magnetic sensor elements 12 used to calculate the traveling speed of the railway vehicle 3 is selected according to the traveling speed of the railway vehicle 3 and the rail alignment during traveling.

[0033] The on-board control device 30 repeatedly calculates the running speed of the railway vehicle 3 at a predetermined time interval. For this purpose, a combination (sensor set) of two magnetic sensor elements 12 with an arrangement interval according to the previously calculated running speed, which is the current (latest) running speed, is selected. Specifically, the sensor set is selected such that magnetic sensor elements 12 located farther apart are selected when the current running speed satisfies a second speed condition, which is a condition faster than the first speed condition, than when the current running speed satisfies the first speed condition. In other words, when the running speed is high, magnetic sensor elements 12 with a combination located farther apart are selected compared to when the running speed is low.

[0034] 6 and 7 are diagrams showing an example of selection of a combination (sensor set) of two magnetic sensor elements 12 based on the traveling speed. Fig. 6 shows a case where the second speed condition is satisfied, and Fig. 7 shows a case where the first speed condition is satisfied. The second speed condition is that the traveling speed is equal to or higher than a threshold speed (e.g., 20 km / h), and the first speed condition is that the traveling speed is less than the threshold speed.

[0035] As shown in Fig. 6, when the running speed satisfies the second speed condition, that is, when the running speed is high, a combination (sensor set) of magnetic sensor elements 12 that are furthest apart along the running direction is selected. In the example of Fig. 6, since the magnetic sensor unit 10 has four rows of magnetic sensor elements 12 arranged in the longitudinal direction of the railcar 3, four sets ((A,M), (B,N), (C,O), (D,P)) of combinations of the magnetic sensor element 12 in the first row (front row) and the magnetic sensor element 12 in the fourth row (rear row) are selected.

[0036] 7, when the running speed satisfies the first speed condition, that is, when the running speed is low, a combination (sensor set) of two adjacent magnetic sensor elements 12 along the running direction is selected. In the example of FIG. 7, a total of 12 sets are selected, including four sets ((A, E), (B, F), (C, G), (D, H)) of the magnetic sensor elements 12 in the first row (front row) and the magnetic sensor elements 12 in the second row, four sets (E, I), (F, J), (G, K), (HL)) of the magnetic sensor elements 12 in the second row and the magnetic sensor elements 12 in the third row, and four sets ((I, M), (J, N), (K, O), (L, P)) of the magnetic sensor elements 12 in the third row and the magnetic sensor elements 12 in the fourth row (last row).

[0037] In this way, when the current traveling speed is fast, a combination (sensor set) of two magnetic sensor elements 12 that are farther apart in the traveling direction is selected compared to when the current traveling speed is slow. This is because the detection values ​​by the magnetic sensor elements 12 are discrete values ​​sampled at a predetermined sampling interval. In other words, when the traveling speed is fast, the position change per sampling interval (i.e., the traveling distance per sampling interval) becomes large, and the resolution of the detection value by the magnetic sensor elements 12 becomes low. As a result, the determination error of the time shift Δt (see FIG. 3), which is the time difference between the waveforms of the magnetic flux density, which is the time series data of the detection values ​​of each of the two magnetic sensor elements 12, becomes large, and the error of the traveling speed v (=d / Δt) calculated from this time shift Δt becomes large.

[0038] Furthermore, the on-board control device 30 selects a combination (sensor set) of two magnetic sensor elements 12 depending on the rail alignment during travel. Specifically, the on-board control device 30 selects magnetic sensor elements 12 located farther apart when the rail alignment during travel satisfies a second linearity condition indicating that the rail alignment is closer to a straight line or is a straight line than a first linearity condition indicating that the rail alignment is a curve satisfying a predetermined curvature condition. In other words, when the rail alignment is a curve with a large curvature, the on-board control device 30 selects magnetic sensor elements 12 located closer together than when the rail alignment is a curve with a small curvature or is a straight line.

[0039] For example, the first linearity condition is that the curvature of the running position is equal to or greater than the threshold curvature, and the second linearity condition is that the curvature is less than the threshold curvature. If the curvature of the running position satisfies the first linearity condition, that is, if the rail alignment during running is a sharp curve, a combination (sensor set) of two magnetic sensor elements 12 adjacent to each other along the running direction is selected as shown in Fig. 7. If the curvature of the running position satisfies the second linearity condition, that is, if the rail alignment during running is a gentle curve or a straight line, the above-mentioned condition related to the running speed is given priority, and a combination (sensor set) of the magnetic sensor elements 12 is selected depending on whether the running speed satisfies the first speed condition or the second speed condition.

[0040] This is because, when the rail alignment during travel is curved, the positions (trajectories) through which two magnetic sensor elements 12 pass in real space may differ. More specifically, when travelling on a curve, the car body moves with the turning of the bogie (generation of a bogie angle), so the passing trajectory in space is determined according to the installation positions of the magnetic sensor elements 12. As a result, the shape 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, may differ, resulting in a large error in the time shift Δt (see FIG. 3) of the waveform, and a large error in the travelling speed v (=d / Δt) calculated from this time shift Δt. For this reason, when the rail alignment during travel is curved with a certain degree of curvature or more, a combination (sensor set) of two magnetic sensor elements 12 that are closer (adjacent) along the travelling direction is selected so as to reduce the difference in the shape of the speed density waveform.

[0041] In this manner, a combination (sensor set) of two magnetic sensor elements 12 used to calculate the running speed of the railway vehicle 3 is selected from among the magnetic sensor elements 12 possessed by the magnetic sensor unit 10. Then, for each selected combination (sensor set), the running speed v of the railway vehicle 3 is calculated according to the above formula (1) from the time shift Δt of the waveforms of the magnetic flux density, which is time-series data of the detection values ​​of each of the two magnetic sensor elements 12, and the arrangement interval d of the two magnetic sensor elements 12 along the running direction of the railway vehicle 3 (see FIG. 3). Then, a predetermined statistical calculation (e.g., calculation of an average value) is performed on the running speed calculated for each combination (sensor set) of two magnetic sensor elements 12, to finally determine the running speed.

[0042] In this embodiment, when calculating the running speed, a plurality of combinations are selected as the combination of the magnetic sensor elements 12, but the arrangement interval d of the two magnetic sensor elements 12 along the running direction of the railway vehicle 3 in the selected combination is the same for each combination. Therefore, the time shift Δt of the magnetic flux density waveform may be obtained for each selected combination (sensor pair) of the two magnetic sensor elements 12, and the time shift Δt obtained by performing a predetermined statistical calculation (for example, calculation of the average value or calculation of the median value) on these time shifts Δt may be set as the final time shift Δt to be determined for the magnetic sensor unit 10, and the running speed may be calculated using this time shift Δt.

[0043] Also, the magnetic sensor elements 12 (four in the example of FIG. 2) in each row arranged in the left-right direction in the magnetic sensor unit 10 may be grouped together, and the traveling speed may be calculated based on the time series data of the detection values ​​of two groups selected from these groups (four in the example of FIG. 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, the average value). For example, in FIG. 2, the group of the magnetic sensor elements 12 A, E, I, and M is selected as the first group, and the group of the magnetic sensor elements 12 D, H, L, and P is selected as the second group. Then, the time series data of the first group is determined from the time series data of the detection values ​​of the magnetic sensor elements 12 A, E, I, and M. Similarly, the time series data of the second group is determined from the time series data of the detection values ​​of the magnetic sensor elements 12 D, H, L, and P. Next, a time lag Δt is determined from the time series data of the first group and the time series data of the second group, and the traveling speed is calculated using this time lag Δt.

[0044] [Function configuration] Fig. 8 is a block diagram showing the functional configuration of the on-board control device 30. According to Fig. 8, the on-board 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 kind of computer.

[0045] The operation unit 102 is realized by an input device such as a button switch, a touch panel, or a keyboard, and outputs an operation signal corresponding to the operation performed to the processing unit 200. The display unit 104 is realized by a display device such as an LCD (Liquid Crystal Display) or a touch panel, and performs various displays corresponding to display signals from the processing unit 200. The sound output unit 106 is realized by a sound output device such as a speaker, and performs various sound outputs corresponding to sound signals from the processing unit 200. The communication unit 108 is realized by a wired or wireless communication device, and communicates with an external device via a given communication network.

[0046] The processing unit 200 is realized by an arithmetic device such as a CPU (Central Processing Unit), and issues instructions and transfers data to each unit constituting the on-board control device 30 based on the programs, data, etc. stored in the storage unit 300, thereby controlling the entire on-board control device 30. The processing unit 200 also executes a speed measurement program 302 stored in the storage unit 300, thereby functioning as each of the functional blocks of a calculation unit 202, a selection unit 204, and a rail alignment detection unit 206. However, these functional blocks can also be configured as independent arithmetic circuits using an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc.

[0047] The calculation unit 202 calculates the traveling speed based on time series data of the detection values ​​of the magnetic sensor elements 12, which are magnetic detection units, and the relative positional relationship of each of the magnetic sensor elements 12. In addition, the calculation unit 202 calculates the traveling speed using the time series data of the detection values ​​of the magnetic sensor elements 12 selected by the selection unit 204.

[0048] Specifically, the calculation of the running speed is repeated at a predetermined time interval. In one calculation of the running speed, for each combination (sensor pair) of two magnetic sensor elements 12 selected by the selection unit 204, the running speed v of the railway vehicle 3 is calculated according to the above formula (1) from the time shift Δt which is the difference in the time direction between the waveforms of magnetic flux density which are the time series data of the detection values ​​of each of the two magnetic sensor elements 12, and the arrangement interval d of the two magnetic sensor elements 12 along the running direction of the railway vehicle 3. Then, a predetermined statistical calculation (e.g., calculation of an average value) is performed on the running speed calculated for each combination (sensor pair) of two magnetic sensor elements 12 to finally determine the running speed.

[0049] Time series data of the detection values ​​of the magnetic sensor elements 12 can be extracted from the detection data 320. The detection data 320 is data in which the magnetic flux density values, which are detection values, of each of the magnetic sensor elements 12 possessed by the magnetic sensor unit 10 are associated with the detection time and stored. The arrangement interval d of the magnetic sensor elements 12 can be acquired from the magnetic sensor unit arrangement data 310. The magnetic sensor unit arrangement data 310 is data that defines the arrangement (such as the relative positional relationship between the front, rear, left and right and the arrangement interval) of the magnetic sensor elements 12 possessed by the magnetic sensor unit 10. The traveling speed calculated by the calculation unit 202 is associated with the calculation time and stored as speed data 322.

[0050] The selection unit 204 selects M (N≧M≧2) magnetic sensor elements 12 from among N (N≧2) magnetic sensor elements 12 that the magnetic sensor unit 10, which is a detection unit, has at positions distant in the traveling direction. The selection unit 204 also selects the magnetic sensor elements 12 based on the current traveling speed. For example, the selection unit 204 selects the magnetic sensor elements 12 at positions farther away when the current traveling speed satisfies a second speed condition, which is a condition faster than the first speed condition, than when the current traveling speed satisfies the first speed condition. The selection unit 204 also selects the magnetic sensor elements 12 based on the rail linearity detected by the rail linearity detection unit 206. For example, the selection unit 204 selects the magnetic sensor elements 12 at positions farther away when the rail linearity detected by the rail linearity detection unit 206 satisfies a second linearity condition, which indicates that the rail linearity is closer to or is a straight line than the first linearity condition, than when the rail linearity detected by the rail linearity detection unit 206 satisfies a first linearity condition, which indicates that the rail linearity is a curve that satisfies a predetermined curvature condition.

[0051] Specifically, the second speed condition is that the running speed is equal to or greater than the threshold speed, and the first speed condition is that the running speed is less than the threshold speed. If the running speed satisfies the second speed condition, that is, if the running speed is high, a combination (sensor set) of magnetic sensor elements 12 that are farthest apart along the running direction is selected. If the running speed satisfies the first speed condition, that is, if the running speed is low, a combination (sensor set) of two magnetic sensor elements 12 adjacent along the running direction is selected. The calculation unit 202 repeatedly calculates the running speed at a predetermined time interval, and the latest running speed (more specifically, the running speed calculated last time) calculated by the calculation unit 202 is set as the current running speed. The threshold speeds that are the first speed condition and the second speed condition are determined as the speed condition data 312.

[0052] In addition, the first linearity condition is that the curvature of the running position is equal to or greater than the threshold curvature, and the second linearity condition is that the curvature is less than the threshold curvature. If the curvature of the running position satisfies the first linearity condition, that is, if the rail alignment during running is a relatively sharp curve, a combination (sensor set) of two magnetic sensor elements 12 adjacent to each other along the running direction is selected. If the curvature of the running position satisfies the second linearity condition, that is, if the rail alignment during running is a relatively gentle curve or a straight line, the above-mentioned condition related to the running speed is given priority, and a combination (sensor set) of the magnetic sensor elements 12 is selected depending on whether the running speed satisfies the first speed condition or the second speed condition. The threshold curvatures that are the first linearity condition and the second linearity condition are determined as linearity condition data 314.

[0053] The rail linearity detection unit 206 detects the rail linearity during travel. Specifically, it detects the rail curvature as the rail linearity. For example, a database in which positions (positions on the rail expressed in kilometers) and curvatures are associated with each other may be prepared and stored, and the curvature corresponding to the current travel position may be acquired. Alternatively, a geomagnetic sensor for measuring the curvature may be separately installed, and the rail curvature may be calculated inferentially from the amount of change in orientation per unit time along the travel direction obtained from the detection value of this geomagnetic sensor. Alternatively, the rail curvature may be calculated inferentially from the amount of change in orientation of the geomagnetic field using the magnetic sensor element 12.

[0054] Returning to Figure 8, the memory unit 300 is realized by a storage device such as a hard disk, ROM (Read Only Memory), RAM (Random Access Memory), etc., and stores programs, data, etc. that the processing unit 200 uses to comprehensively control the on-board control device 30. It is also used as a working area for the processing unit 200, and temporarily stores the results of calculations performed by the processing unit 200 in accordance with various programs, and input data via the operation unit 102 and communication unit 108, etc.

[0055] In this embodiment, the storage unit 300 stores a speed measurement program 302 , magnetic sensor unit arrangement data 310 , speed condition data 312 , linear condition data 314 , detection data 320 , and speed data 322 .

[0056] [Processing flow] 9 is a flowchart explaining the flow of the traveling speed calculation process performed by the on-board control device 30. This process is realized by the processing unit 200 executing the speed measurement program 302, and is started, for example, prior to departure from the starting station.

[0057] First, the selection unit 204 selects a combination (sensor set) of two magnetic sensor elements 12 used to calculate the traveling speed. That is, it determines whether the current traveling speed is high or not, that is, whether the second speed condition is satisfied or not. If the current traveling speed is high (satisfies the second speed condition) (step S1: YES), the rail linearity detection unit 206 then detects the rail linearity during traveling (step S3). Next, the selection unit 204 determines whether the detected rail linearity is a straight line or a relatively gentle curve, that is, whether the second curvature condition is satisfied or not.

[0058] If the rail linearity is a straight line or a relatively gentle curve (satisfies the second curvature condition) (step S5: YES), the selection unit 204 selects a combination (sensor set) of magnetic sensor elements 12 that are spaced apart along the traveling direction from among the magnetic sensor elements 12 possessed by the magnetic sensor unit 10 (step S7). On the other hand, if the rail linearity is neither a straight line nor a relatively gentle curve (does not satisfy the second curvature condition; is a relatively sharp curve) (step S5: NO), or if the current traveling speed is not high (does not satisfy the second speed condition; is low) (step S1: NO), the selection unit 204 selects a combination (sensor set) of magnetic sensor elements 12 that are adjacent along the traveling direction from among the magnetic sensor elements 12 possessed by the magnetic sensor unit 10 (step S9).

[0059] Next, the calculation unit 202 calculates the traveling speed by using the selected combination (sensor set) of the magnetic sensor elements 12 (step S11). Then, the calculation unit 202 associates the calculated traveling speed with the calculation time and adds it to the speed data 322 to update it (step S13).

[0060] Then, it is determined whether the process is to be terminated by satisfying a termination condition such as arrival at a terminal station, and if not (step S15: NO), the process returns to step S1 and repeats the same process. If it is to be terminated (step S15: YES), the process is terminated.

[0061] [Effects] According to this embodiment, a new method for measuring the traveling speed on the train with high accuracy can be realized. That is, the time series data of the magnetic detection values ​​by each of the magnetic sensor elements 12 of the magnetic sensor unit 10 mounted on the railcar 3 changes almost the same over time, but since the magnetic sensor elements 12 are mounted at positions apart in the traveling direction, a time lag occurs in the detection timing for each of the magnetic sensor elements 12. As a result, the traveling speed can be measured from the relative positional relationship in the traveling direction of the magnetic sensor elements 12 and the time lag of the time series data of the detection values. In addition, since the magnetic field is resistant to disturbances, the magnetic detection value in the magnetic field generated by the magnetism of the rail 5 can be used to realize a highly accurate measurement of the traveling speed on the train. In this way, a highly accurate measurement of the traveling speed on the train can be realized with a configuration that does not require ground equipment.

[0062] Incidentally, the applicable embodiments of the present invention are not limited to the above-described embodiments, and can of course be modified as appropriate without departing from the spirit of the present invention.

[0063] (A) Configuration of the magnetic sensor In the above embodiment, the magnetic sensor unit 10, which is the detection unit, has a total of 16 magnetic sensor elements 12 arranged in a plane, four rows in the left-right direction of the railway vehicle 3 and four rows in the running direction (front-rear direction) (=N (≧3) pieces) (see FIG. 2 ), but the arrangement and number of the magnetic sensor elements 12 in the magnetic sensor unit 10 are not limited to this. The magnetic sensor unit 10 may be configured with a total of four magnetic sensor elements 12 arranged in a plane, two rows in the left-right direction of the railway vehicle 3 and two rows in the running direction (front-rear direction). Due to restrictions on installation space, cost, etc., the number of magnetic sensor elements 12 to be arranged may be reduced, and the magnetic sensor unit 10 may be configured with a minimum of two magnetic sensor elements 12. In this case, the magnetic sensor elements 12 are arranged at least apart in the running direction (front-rear direction).

[0064] (B) Selection of a combination (sensor pair) of two magnetic sensor elements 12 In the above embodiment, the combination (sensor set) of two magnetic sensor elements 12 used to calculate the running speed of the railway vehicle 3 is selected according to both the running speed of the railway vehicle 3 and the rail alignment while it is running, but it may be selected according to only one of them.

[0065] For example, when making a selection based only on the rail alignment during travel, the following selection can be made: That is, if the curvature of the travel position satisfies the first linearity condition, i.e., the rail alignment during travel is a relatively sharp curve, a combination (sensor pair) of two magnetic sensor elements 12 adjacent in the travel direction is selected (see FIG. 7). On the other hand, if the curvature of the travel position satisfies the second linearity condition, i.e., the rail alignment during travel is a straight line or a relatively gentle curve, a combination (sensor pair) of two magnetic sensor elements 12 that are farther apart in the travel direction is selected (see FIG. 6).

[0066] (C) Velocity and Linear Conditions In addition, in the above-described embodiment, a two-stage condition is used in which the speed condition is a first speed condition and a second speed condition with a threshold speed as a boundary, and the linear condition is a first curvature condition and a second curvature condition with a threshold curvature as a boundary. However, a three-stage or more condition may also be used.

[0067] For example, the speed condition may be three-stage conditions including a first speed condition corresponding to a low speed, a second speed condition corresponding to a high speed, and a third speed condition corresponding to a medium speed. When the third speed condition is satisfied, a combination (sensor set) of the magnetic sensor elements 12 in the first row (front row) and the magnetic sensor elements 12 in the third row, and a combination (sensor set) of the magnetic sensor elements 12 in the second row and the magnetic sensor elements 12 in the fourth row (rear row) are selected, which are combinations (sensor sets) of the magnetic sensor elements 12 that are moderately separated from each other (see Figs. 6 and 7). Similarly, the curvature condition may be three-stage conditions including a first curvature condition corresponding to a straight line, a second curvature condition corresponding to a sharp curve, and a third curvature condition corresponding to a gentle curve between a straight line and a sharp curve.

[0068] (D) Magnetic detection In locations where the rails 5 are not magnetized or are magnetized but only weakly magnetized, magnetic markers (permanent magnets) may be installed on the track, such as between the left and right rails 5. Furthermore, if the installation positions of the magnetic markers are known, detection of the magnetic markers can also be used to correct the position on the train. [Explanation of symbols]

[0069] 1...Onboard equipment 10...Magnetic sensor section 12...Magnetic sensor element 30…On-board control device 200... Processing section 202...Calculation section 204...Selection section 206...Rail linearity detection unit 300...Storage section 302...Speed ​​measurement program 310...Magnetic sensor unit layout data 312...Speed ​​condition data 314...Linear condition data 320…Detection data 322…Speed ​​data 3. Railway vehicles 5…Rail

Claims

1. An on-board device mounted on a vehicle running on a rail, a detection unit having a plurality of magnetic detection units spaced apart in a running direction for detecting a magnetic field generated by magnetism of the rail; a calculation unit that calculates a running speed based on time series data of the detection values ​​of the magnetic detection units and a relative positional relationship between the magnetic detection units; An on-board device comprising:

2. The detection unit has N (N≧3) magnetic detection units at positions spaced apart in the traveling direction, A selection unit that selects M magnetic detection units (N≧M≧2) from the N magnetic detection units; Further comprising: The calculation unit calculates a traveling speed by using time series data of the detection value of the magnetic detection unit selected by the selection unit. The on-board device according to claim 1.

3. The selection unit selects the magnetic detection unit based on a current running speed. The on-board device according to claim 2.

4. the selection unit selects the magnetic detection unit located farther away when the current traveling speed satisfies a second speed condition, the second speed condition being faster than the first speed condition, than when the current traveling speed satisfies the first speed condition. The on-board device according to claim 3.

5. A rail alignment detection unit that detects the rail alignment while the vehicle is running; Further comprising: The selection unit selects the magnetic detection unit based on the rail alignment detected by the rail alignment detection unit. The on-board device according to claim 2.

6. the selection unit selects the magnetic detection unit located farther away when the rail linearity detected by the rail linearity detection unit satisfies a second linearity condition indicating that the rail linearity detected by the rail linearity detection unit is a curve satisfying a predetermined curvature condition, the second linearity condition indicating that the rail linearity is closer to a straight line or is a straight line than the first linearity condition. The on-board device according to claim 5.

7. the magnetic detection unit has magnetic sensor elements arranged apart in a left-right direction of the vehicle, a data determination unit that determines time-series data of detection values ​​of the magnetic detection unit based on time-series data of detection values ​​of the magnetic sensor elements that constitute the magnetic detection unit; The on-board device according to any one of claims 1 to 6, further comprising:

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