Patent Application
20240003937
The present disclosure relates to an on-board control device to be installed in a train including an acceleration sensor, and an acceleration sensor diagnosis method.
In recent train control systems such as a communications based train control (CBTC) or a digital automatic train control (ATC), an on-board control device installed in a train calculates a train position using a tachometer, a pick-up coil, or the like and calculates a brake pattern used to control train intervals based on the calculated train position. Therefore, it is important to accurately manage the train position by the on-board control device. However, when the on-board control device calculates the train position, a train speed, or the like using the tachometer, the pick-up coil, or the like, an error of the train position increases if slipping or sliding of wheels of the train occurs.
For such a problem, by installing an acceleration sensor, the train can detect slipping or sliding by comparing an acceleration detected by the acceleration sensor and an acceleration calculated from a signal of the tachometer and correct the train position, the train speed, or the like in a case where slipping or sliding is detected. In order to accurately detect slipping or sliding and correct the train position, the train speed, or the like, the train needs to periodically confirm soundness of the acceleration sensor. Patent Literature 1 discloses a technique for diagnosing an acceleration sensor by a vehicle control system.
However, according to the related art described above, the vehicle control system includes a vibration source that vibrates the acceleration sensor in order to diagnose the soundness of the acceleration sensor. Therefore, there has been a problem in that a device configuration of the vehicle control system becomes complicated.
The present disclosure has been made in view of the above, and an object is to obtain an on-board control device that can periodically diagnose soundness of an acceleration sensor with a simple configuration.
To solve the above problem and achieve an object, the present disclosure is directed to an on-board control device to be installed in a train. The on-board control device includes: a communication unit to be communicable with a tachometer that outputs pulses corresponding to the number of revolutions of wheels of the train, a pick-up coil that receives a telegraph that includes identification information of a ground coil from the ground coil, an acceleration sensor a detection axis of which is provided along a traveling direction of the train, and a master controller; a storage unit to store information regarding a gradient value at each position on a train line where the train travels; and a control unit to specify a train position of the train by using information acquired from the pick-up coil and the tachometer, determine a traveling state of the train from information acquired from the master controller, and, when the train coasts or is stopped, diagnose soundness of the acceleration sensor based on a comparison result obtained by comparing a first acceleration of the train output from the acceleration sensor with a second acceleration in a traveling direction of the train calculated by using a gravity acceleration and a gradient value at the train position.
According to the present disclosure, an effect can be obtained that an on-board control device can periodically diagnose soundness of an acceleration sensor with a simple configuration.
Hereinafter, an on-board control device and an acceleration sensor diagnosis method according to embodiments of the present disclosure will be described in detail with reference to the drawings.
The acceleration sensor 1 is installed such that a first detection axis that is a detection axis is provided along a traveling direction of the train 10.
The pick-up coil 3 receives a telegraph including an identifier (ID) that is identification information of the ground coil 11 from the ground coil 11 installed on the ground, and outputs the ID of the ground coil 11 to the on-board control device 2.
The master controller 4 is provided around an operator's seat (not illustrated) of the train 10 and accepts an operation by an operator. In
The tachometer 5 generates pulses corresponding to the number of revolutions of a wheel of the train 10 and outputs the generated pulses to the on-board control device 2.
The on-board wireless device 6 performs wireless communication with the ground wireless device 12. The on-board wireless device 6 transmits data such as positional information on the train 10 that is calculated by the on-board control device 2 and acquired from the on-board control device 2 to the ground wireless device 12 through wireless communication via the on-board antenna 7. Furthermore, the on-board wireless device 6 receives control information such as information on stop limit of the train 10 calculated by the ground device 13 from the ground wireless device 12 through wireless communication via the on-board antenna 7.
The brake device 8 executes processing for deceleration, processing for stop, or the like of the train 10, based on a brake command from the on-board control device 2.
The propulsion control device 9 drives an electric motor that rotates the wheels based on a driving command from the on-board control device 2 and executes acceleration processing of the train 10.
The on-board control device 2 is installed in the train 10 and controls traveling and stop of the train 10 at the time of the operation of the train 10. The on-board control device 2 periodically calculates the train position of the train 10. Specifically, the on-board control device 2 calculates a train speed, a traveling distance, or the like of the train 10 from the number of pulses acquired from the tachometer 5 and a diameter of the wheel of the train 10 and further calculates the train position of the train 10 using the telegraph acquired from the pick-up coil 3, that is, positional information on the ground coil 11. The on-board control device 2 transmits the calculated positional information to the ground wireless device 12 via the on-board wireless device 6 and the on-board antenna 7. Furthermore, the on-board control device 2 receives the information on stop limit of the train 10 calculated by the ground device 13 from the ground wireless device 12 via the on-board antenna 7 and the on-board wireless device 6. The on-board control device 2 generates a stop deceleration pattern using the information on stop limit or the like and controls traveling of the train 10 using the generated stop deceleration pattern. Specifically, when the train speed of the train 10 exceeds the stop deceleration pattern, the on-board control device 2 outputs the brake command to the brake device 8. Furthermore, the on-board control device 2 periodically diagnoses soundness of the acceleration sensor 1. An operation for periodically diagnosing the soundness of the acceleration sensor 1 by the on-board control device 2 will be described later.
In the train control system 100, a ground system including devices provided on the ground includes the ground coil 11, the ground wireless device 12, and the ground device 13.
The ground coil 11 transmits a telegraph including the ID that is the identification information of the ground coil 11. Note that, although only one ground coil 11 is illustrated in the example in
The ground wireless device 12 performs wireless communication with the train 10, specifically, the on-board wireless device 6 via the on-board antenna 7. The ground wireless device 12 receives the data such as the positional information on the train 10 calculated by the train 10 through wireless communication. Furthermore, the ground wireless device 12 transmits the control information such as the information on stop limit of the train 10 calculated by the ground device 13 to the train 10 through wireless communication.
The ground device 13 is connected to the ground wireless device 12, receives the positional information on the train 10 from the on-board control device 2 of the train 10 via the on-board wireless device 6, the on-board antenna 7, and the ground wireless device 12 and manages the positional information on the train 10 that travels in a jurisdiction area. Note that one train 10 is illustrated in the example in
In the example in
Subsequently, the operation for periodically diagnosing the soundness of the acceleration sensor 1 by the on-board control device 2 and the configuration of the on-board control device 2 will be described in detail.
The communication unit 21 communicates with the acceleration sensor 1, the pick-up coil 3, the master controller 4, the tachometer 5, the on-board wireless device 6, the brake device 8, and the propulsion control device 9.
The storage unit 22 stores information regarding a gradient value at each position on the train line where the train 10 travels, and information in which the ID of the ground coil 11 and the installation position of the ground coil 11 are associated.
The control unit 23 specifies the train position of the train 10 using the information acquired from the pick-up coil 3 and the information acquired from the tachometer 5. Specifically, the control unit 23 specifies the train position of the train 10 using the ID of the ground coil 11 received from the ground coil 11 via the pick-up coil 3 and the communication unit 21, and the installation position of the ground coil 11 corresponding to the ID of the ground coil 11 stored in the storage unit 22. The control unit 23 calculates a traveling distance from the ground coil 11 based on the number of pulses corresponding to the number of revolutions of the wheel obtained from the tachometer 5, and updates the train position of the train 10 as needed. The control unit 23 determines a traveling state of the train 10 from the information acquired from the master controller 4. Specifically, the control unit 23 determines whether the train 10 is accelerating, decelerating, coasting, or stopped. The control unit 23 compares a first acceleration that is an acceleration of the train 10 output from the acceleration sensor 1 with a second acceleration, which is an acceleration in the traveling direction of the train 10 calculated using the gravity acceleration g and the gradient value at the train position of the train 10, when the train 10 is coasting or stopped. The second acceleration is a component of the gravity acceleration g in the train traveling direction. The control unit 23 diagnoses the soundness of the acceleration sensor 1, based on a comparison result.
In general, when the train 10 accelerates or decelerates under a special situation in which a surface of the railway track where the train 10 is traveling is wet, wheel slipping or sliding may occur. When slipping or sliding of the wheel of the train 10 occurs, the number of pulses generated by the tachometer 5 does not match an actual train speed, traveling distance, or the like of the train 10. Therefore, the on-board control device 2 executes processing for determining whether or not slipping or sliding of the wheel of the train 10 has occurred, and correcting the train position of the train 10 if slipping or sliding has occurred. Here, in the train 10, the acceleration sensor 1 is not affected by slipping, sliding, or the like of the wheel. Therefore, if the acceleration sensor 1 is in a sound state, it is preferable that the on-board control device 2 detects idling or sliding of the wheel using the acceleration output from the acceleration sensor 1 that is not affected by slipping, sliding, or the like of the wheel, and performs correction when slipping or sliding has occurred. Therefore, the on-board control device 2 periodically diagnoses the soundness of the acceleration sensor 1.
The on-board control device 2 acquires the ID of the ground coil 11 via the pick-up coil 3 (step S201). The on-board control device 2 specifies a position corresponding to the ID of the ground coil 11, based on the information in which the ID of the ground coil 11 and the installation position of the ground coil 11 are associated and stored in the storage unit 22 (step S202). The on-board control device 2 acquires pulses corresponding to the number of revolutions of the wheel of the train 10 from the tachometer 5, calculates the traveling distance from the ground coil 11, and updates a train position x of the train 10 as needed (step S203). The on-board control device 2 specifies a gradient value Gx at the train position x of the train 10 (step S204). As described above, the storage unit 22 stores a gradient value at each position on the train line where the train 10 travels, that is, the gradient value Gx corresponding to the train position x of the train 10. An expression method of the gradient value Gx, that is, a unit is %, h, or the like. Here, in order to simplify a coefficient, as illustrated in
When the train 10 is coasting (step S206: Yes) or when the train 10 is not coasting (step S206: No) but is stopped (step S207: Yes), the on-board control device 2 determines whether or not the first acceleration detected by the acceleration sensor 1 matches the second acceleration that is the component of the gravity acceleration g (step S208) in the traveling direction of train. If the train 10 is coasting (step S206: Yes) or stopped (step S207: Yes), an acceleration other than the acceleration caused by the gravity acceleration g is not generated; accordingly, the first acceleration output from the acceleration sensor 1 has the same value as that of the second acceleration, that is, “g×sin θ≈g×Gx”, the component of the gravity acceleration g in the train traveling direction. The on-board control device 2 may calculate a difference between the first acceleration (a_Sen_x) and the second acceleration (g×Gx), in consideration of a measurement error or the like of the acceleration sensor 1 and determine that the accelerations match when an absolute value of the difference falls within a first threshold THRE1. The first threshold THRE1 is a threshold that is specified in advance in consideration of the measurement error or the like of the acceleration sensor 1, and is, for example, stored in the storage unit 22. Note that, the on-board control device 2 can detect whether the train 10 is in an acceleration state, a deceleration state, or a coasting state because the on-board control device 2 acquires the information regarding the traveling state from the master controller 4. Furthermore, the on-board control device 2 can detect whether the train 10 is stopped because the on-board control device 2 has acquired the pulses corresponding to the number of revolutions of the wheel from the tachometer 5.
When the first acceleration and the second acceleration do not match (step S208: No), the on-board control device 2 determines that the acceleration sensor 1 is anomalous (step S209). When the first acceleration and the second acceleration match (step S208: Yes), the on-board control device 2 determines that the acceleration sensor 1 is normal (step S210). Note that, when the train 10 is not coasting (step S206: No) and the train 10 is not stopped (step S207: No), the on-board control device 2 assumes that the acceleration sensor 1 is normal without diagnosing the soundness of the acceleration sensor 1 at this operation (step S211) and determines that the acceleration sensor 1 is normal (step S210).
The description returns to the flowchart in
When the difference between the third acceleration (α_TM) and the first acceleration (α_Sen_x) is larger than a first slipping threshold SLIP1 used to detect slipping (step S301: Yes), the on-board control device 2 determines that slipping of the wheel of the train 10 has occurred and executes the correction processing (step S302). Specifically, while the slipping state continues, the on-board control device 2 calculates the train speed and the train position of the train 10 using the first acceleration (α_Sen_x) output from the acceleration sensor 1.
When the difference between the third acceleration (α_TM) and the first acceleration (α_Sen_x) is equal to or less than the first slipping threshold SLIP1 (step S301: No) and is smaller than a first sliding threshold SLIDE1 used to detect sliding (step S303: Yes), the on-board control device 2 determines that sliding of the wheel of the train 10 has occurred and executes the correction processing (step S304). Specifically, while the sliding state continues, the on-board control device 2 calculates the train speed and the train position of the train 10 using the first acceleration (α_Sen_x) output from the acceleration sensor 1.
When the difference between the third acceleration (α_TM) and the first acceleration (α_Sen_x) is equal to or more than the first sliding threshold SLIDE1 (step S303: No), the on-board control device 2 determines that neither sliding nor slipping of the wheel of the train 10 has occurred and determines that the correction processing is unnecessary (step S305). In this way, the on-board control device 2 determines whether slipping has occurred or not based on a comparison result obtained by comparing the calculated difference with the first slipping threshold used to detect slipping, and determines whether or not sliding has occurred based on a comparison result obtained by comparing the calculated difference with the first sliding threshold used to detect sliding.
The description returns to the flowchart in
When the fourth acceleration is larger than a second slipping threshold SLIP2 used to detect slipping (step S401: Yes), the on-board control device 2 determines that slipping of the wheel of the train 10 has occurred and executes the correction processing (step S402).
Specifically, when the on-board control device 2 detects slipping and calculates the train position of the train 10 based on the pulse of the speed generator 5, a calculated head position of the of the train 10 is ahead of an actual head position of the train 10, and a margin for control is secured. Therefore, a pulse signal of the tachometer 5 is used as it is. On the other hand, a calculated rear position of the train 10 is ahead of an actual rear position of the train 10, which results in calculating a position for stop limit of the subsequent train with less margin for control. Therefore, for example, the on-board control device 2 performs correction so as to secure the margin for control with a method for calculating the train position of the train 10 on the assumption that the train 10 has traveled at a constant speed from a time m1 seconds before the time when slipping is detected, for example.
When the fourth acceleration is equal to or less than the second slipping threshold SLIP2 (step S401: No) and is smaller than a second sliding threshold SLIDE2 used to detect sliding (step S403: Yes), the on-board control device 2 determines that sliding of the wheel of the train 10 has occurred and executes the correction processing (step S404). Specifically, when the on-board control device 2 detects sliding and calculates the train position of the train 10 based on the pulse signal of the speed generator 5, the calculated head position of the train 10 is behind the actual head position of the train 10, which reduces margin for control because the on-board control device 2 determines a timing to output the brake command based on a decision that separation from the brake pattern is larger than actual separation. Therefore, the on-board control device 2 performs correction for securing the margin for control with a method for calculating the train position of the train 10 or the like on the assumption with that the train has traveled at a constant speed from a time m2 seconds before the time when sliding is detected, for example. On the other hand, the calculated rear position of the train 10 is behind the actual rear position of the train 10, the stop limit position of the subsequent train is calculated with margin for control secured. Therefore, the on-board control device 2 uses the pulse signal of the tachometer 5 as it is.
When the fourth acceleration is equal to or more than the second sliding threshold SLIDE2 (step S403: No), the on-board control device 2 determines that neither slipping nor sliding of the wheel of the train 10 has occurred, and determines that the correction is unnecessary (step S405). As above, the on-board control device 2 determines whether or not slipping occurs based on a comparison result obtained by comparing the fourth acceleration with the threshold used to detect slipping, and determines whether or not sliding occurs based on a comparison result obtained by comparing the fourth acceleration with the threshold used to detect sliding.
When the acceleration sensor 1 is anomalous (step S101: No), the on-board control device 2 does not use the signal of the acceleration sensor 1, detects slipping or sliding with only the pulse signal of the tachometer 5, and performs correction if slipping or sliding is detected. In this case, a true train position, train speed, acceleration, or the like of the train 10 under slipping or sliding is unknown. Therefore, in order to secure the margin for control, the on-board control device 2 needs to execute excessive correction for speed and position using, for example, a physical limit value, a performance limit value, or the like such as a train maximum acceleration, a train maximum deceleration, and a maximum gradient. Therefore, in the train control system 100, train intervals of the plurality of trains 10 may excessively increase.
On the other hand, when the acceleration sensor 1 is normal (step S101: Yes), the on-board control device 2 can detect slipping or sliding of the wheel of the train 10 using the signal of the acceleration sensor 1 that is not affected even when the wheel of the train 10 slips or slides, and perform correction if slipping or sliding has been detected. As a result, the train intervals of the trains 10 do not become excessive, which results in stabilizing transportation density in the train control system 100.
Subsequently, a hardware configuration of the on-board control device 2 will be described. In the on-board control device 2, the communication unit 21 is an interface such as a communication device. The storage unit 22 is a memory. The control unit 23 is implemented by processing circuitry. The processing circuitry may be a processor and a memory that executes programs stored in the memory or may be dedicated hardware.
Here, the processor 91 may be a central processing unit (CPU), a processing device, an arithmetic device, a microprocessor, a microcomputer, a digital signal processor (DSP), or the like. Furthermore, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable programmable ROM (EPROM), and an Electrically EPROM (EEPROM) (registered trademark), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a digital versatile disc (DVD).
Note that some of the functions of the on-board control device 2 may be implemented by dedicated hardware, and some of the functions may be implemented by software or firmware. In this way, the processing circuitry can implement each function described above by the dedicated hardware, software, firmware, or the combination thereof.
As described above, according to the present embodiment, the on-board control device 2 installed in the train 10 diagnoses the soundness of the acceleration sensor 1 based on the comparison result obtained by comparing the first acceleration detected by the acceleration sensor 1 and the second acceleration that is the component of the gravity acceleration g in the traveling direction of train, when the train 10 is coasting or stopped. Thus, the on-board control device 2 can periodically diagnose the soundness of the acceleration sensor 1 with a simple configuration, without using a vibration source that vibrates the acceleration sensor 1 while the train 10 is traveling. When the acceleration sensor 1 is normal, the on-board control device 2 can improve accuracy in detecting slipping or sliding and can prevent or reduce excessive correction on slipping or sliding even when slipping or sliding has occurred.
In a second embodiment, a case will be described where a train includes a biaxial acceleration sensor.
The biaxial acceleration sensor 1a is an acceleration sensor that includes a first detection axis and a second detection axis. The biaxial acceleration sensor 1a is installed such that the first detection axis is provided along a traveling direction of the train 10a, and the second detection axis is provided to be perpendicular to the first detection axis and along a vertical direction with respect to a floor surface of the train 10a.
When the biaxial acceleration sensor 1a is disposed in the train 10a in this way, an output component in the z-axis direction of the biaxial acceleration sensor 1a, that is, the fifth acceleration should match a value that is uniquely determined based on only a gradient value at a position of the train 10a, regardless of the acceleration of the train 10a, if the biaxial acceleration sensor 1a is normal. As illustrated in
A configuration of the on-board control device 2a is similar to the configuration of the on-board control device 2 according to the first embodiment illustrated in
The on-board control device 2a determines whether or not the fifth acceleration (α_Sen_z) regarding the second detection axis output from the biaxial acceleration sensor 1a, matches the sixth acceleration (g×√(1−Gx2)) in the vertical direction with respect to the floor surface of the train 10 that is calculated using the gravity acceleration g and the gradient value Gx at the train position (step S221). The on-board control device 2a may calculate a difference between the fifth acceleration (α_Sen_z) and the sixth acceleration (g×√(1−Gx2)) in consideration of a measurement error or the like of the biaxial acceleration sensor 1a, and determine that the accelerations match when an absolute value of the difference is within a second threshold THRE2. The second threshold is specified in advance in consideration of the measurement error or the like of the biaxial acceleration sensor 1a, and is, for example, stored in a storage unit 22. The on-board control device 2a performs the determination in step S221, regardless of a traveling state of the train 10a. If the fifth acceleration and the sixth acceleration match (step S221: Yes), the on-board control device 2a determines that a detection unit and a common unit of the second detection axis are normal by the biaxial acceleration sensor 1a (step S222).
Operations in subsequent steps S205 to S208 are the same as the operations in steps S205 to S208 in the flowchart according to the first embodiment illustrated in
As described above, according to the present embodiment, the on-board control device 2a installed in the train 10a can determine whether or not the detection unit 40 of the second detection axis and the common unit 50 of the biaxial acceleration sensor 1a are normal without using a vibration source that vibrates the biaxial acceleration sensor 1a and regardless of the traveling state of the train 10a.
The configurations illustrated in the above embodiments indicate examples and can be combined with other known techniques. Furthermore, the embodiments can be combined with each other, and some configurations can be partially omitted or changed without departing from the scope.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/043698 | 11/24/2020 | WO |
