description
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
TRAIN CONTROL DEVICE AND SLIP-SLIDE DETECTION METHOD;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION
ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN,
WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODAKU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES
THE INVENTION AND THE MANNER IN WHICH IT IS TO BE
PERFORMED
2
DESCRIPTION
Field
[0001] The present disclosure relates to a train control
5 device to be installed on a train, and to a slip-slide
detection method.
Background
[0002] Occurrence of a slip or a slide on a train is
10 conventionally detected using a detection value from a
sensor provided on an axle of the train. Patent Literature
1 discloses a technology in which an on-board device
calculates the velocity from velocity pulses detected by
rotation detection devices provided on multiple axles, and
15 when an error of each velocity determined based on velocity
pulses detected by each rotation detection device exceeds a
threshold, determines that a slip or a slide has occurred.
Citation List
20 Patent Literature
[0003] Patent Literature 1: WO 2017/195316 A
Summary of Invention
Problem to be solved by the Invention
25 [0004] However, the above conventional technology
requires counting of velocity pulses with a short period to
detect occurrence of a slip or a slide on a train. This
results in a reduced number of velocity pulses countable
with a period of counting velocity pulses. This presents a
30 problem in that a large error may occur in the calculated
velocity depending on whether a single velocity pulse falls
within a certain period.
[0005] The present disclosure has been made in view of
3
the foregoing, and it is an object of the present
disclosure to provide a train control device capable of
detecting a slip or a slide occurring on a train with high
accuracy while avoiding a long detection period.
5
Means to Solve the Problem
[0006] In order to solve the above-described problems
and achieve the object, a train control device according to
the present disclosure is installed on a train. The train
10 control device includes: an acquisition unit to obtain
first pulses from a first velocity sensor for detecting the
first pulses, and to obtain second pulses from a second
velocity sensor for detecting the second pulses, the first
pulses having been generated on a first axle of the train,
15 the second pulses having been generated on a second axle of
the train; a storage unit to store the first pulses and the
second pulses; and a control unit to determine occurrence
or non-occurrence of a slip or a slide of the train based
on a pulse ratio, the pulse ratio being a ratio between a
20 number of first pulses detected during a time period in
which the train traveled a given distance among the first
pulses, and a number of second pulses detected during a
time period in which the train traveled the given distance
among the second pulses.
25
Effects of the Invention
[0007] The present disclosure is advantageous in that a
train control device is capable of detecting a slip or a
slide occurring on a train with high accuracy while
30 avoiding a long detection period.
Brief Description of Drawings
[0008] FIG. 1 is a diagram schematically illustrating an
4
example configuration of a train on which a train control
device according to a first embodiment is to be installed.
FIG. 2 is a diagram illustrating an example of pulses
detected by velocity sensors when neither a slip nor a
5 slide is occurring on the train according to the first
embodiment.
FIG. 3 is a diagram illustrating an example of pulses
detected by the velocity sensors when a slip or a slide is
occurring on the train according to the first embodiment.
10 FIG. 4 is a diagram illustrating an example of pulses
detected by the velocity sensors when a slip or a slide has
occurred for a short time period on the train according to
the first embodiment.
FIG. 5 is a diagram illustrating an example, as a
15 comparative example, in which the measurement periods for
counting pulses detected by the velocity sensors are
independent of each other.
FIG. 6 is a first diagram illustrating transition of a
slip-or-slide detection state of the train according to the
20 first embodiment.
FIG. 7 is a second diagram illustrating transition of
the slip-or-slide detection state of the train according to
the first embodiment.
FIG. 8 is a third diagram illustrating transition of
25 the slip-or-slide detection state of the train according to
the first embodiment.
FIG. 9 is a fourth diagram illustrating transition of
the slip-or-slide detection state of the train according to
the first embodiment.
30 FIG. 10 is a flowchart illustrating an operation of
the train control device according to the first embodiment.
FIG. 11 is a diagram illustrating an example of
processing circuitry included in the train control device
5
according to the first embodiment when the processing
circuitry includes a processor and a memory.
FIG. 12 is a diagram illustrating an example of
processing circuitry included in the train control device
5 according to the first embodiment when the processing
circuitry includes a dedicated hardware element.
FIG. 13 is a diagram illustrating an illustrative
image of wheel diameters of wheels provided on the train
according to a second embodiment.
10 FIG. 14 is a diagram illustrating an illustrative
image of a case in which wheel B provided on the train
according to the second embodiment has worn.
FIG. 15 is a diagram illustrating an illustrative
image of a case in which wheel A provided on the train
15 according to the second embodiment has worn.
FIG. 16 is a flowchart illustrating an operation of
the train control device according to the second embodiment.
Description of Embodiments
20 [0009] A train control device and a slip-slide detection
method according to embodiments of the present disclosure
will be described in detail below with reference to the
drawings.
[0010] First Embodiment.
25 FIG. 1 is a diagram schematically illustrating an
example configuration of a train 10 on which a train
control device 20 according to a first embodiment is to be
installed. The train 10 includes a vehicle 11 and a
vehicle 12. The example of FIG. 1 assumes that the train
30 10 is traveling leftward in the figure as indicated by an
arrow 70. FIG. 1 illustrates the train 10 as, but not
limited to, a two-car train including the vehicles 11 and
12 by way of example. The train 10 on which the train
6
control device 20 is to be installed may include three or
more vehicles.
[0011] In the train 10, the vehicle 11 includes the
train control device 20, a velocity sensor 31, axles 41 to
5 44, and wheels 51 to 54 and 61 to 64. The axle 41 has the
wheels 51 and 61 attached thereto. The axle 42 has the
wheels 52 and 62 attached thereto. The axle 43 has the
wheels 53 and 63 attached thereto. The axle 44 has the
wheels 54 and 64 attached thereto. The velocity sensor 31
10 detects a pulse generated on the axle 41. The following
description may refer to the velocity sensor 31 as first
velocity sensor, the axle 41 as first axle, and the pulse
generated on the axle 41 and detected by the velocity
sensor 31 as first pulse.
15 [0012] In the train 10, the vehicle 12 includes a
velocity sensor 32, axles 45 to 48, and wheels 55 to 58 and
65 to 68. The axle 45 has the wheels 55 and 65 attached
thereto. The axle 46 has the wheels 56 and 66 attached
thereto. The axle 47 has the wheels 57 and 67 attached
20 thereto. The axle 48 has the wheels 58 and 68 attached
thereto. The velocity sensor 32 detects a pulse generated
on the axle 47. The following description may refer to the
velocity sensor 32 as second velocity sensor, the axle 47
as second axle, and the pulse generated on the axle 47 and
25 detected by the velocity sensor 32 as second pulse.
[0013] As described above, the train control device 20
is installed on the train 10. The train control device 20
includes an acquisition unit 21, a storage unit 22, and a
control unit 23.
30 [0014] The acquisition unit 21 obtains a first pulse
generated on the axle 41 of the train 10 from the velocity
sensor 31, which detects the first pulse. The acquisition
unit 21 also obtains a second pulse generated on the axle
7
47 of the train 10 from the velocity sensor 32, which
detects the second pulse. The acquisition unit 21 stores
the first pulse and the second pulse obtained, in the
storage unit 22.
5 [0015] The storage unit 22 stores first pulses and
second pulses obtained by the acquisition unit 21. The
storage unit 22 stores the first pulses and the second
pulses obtained after a given time. The storage unit 22
stores, for example, the first pulses and the second pulses
10 obtained by the acquisition unit 21 after the train 10
starts operation of a certain day.
[0016] The control unit 23 compares the number of first
pulses detected during a time period in which the train 10
traveled a given distance among the first pulses stored in
15 the storage unit 22, and the number of second pulses
detected during a time period in which the train 10
traveled the given distance among the second pulses stored
in the storage unit 22. The control unit 23 determines
occurrence or non-occurrence of a slip or a slide of the
20 train 10 based on a pulse ratio, which is a result of
comparison between the number of first pulses and the
number of second pulses. The given distance is,
specifically, an axle-to-axle distance of the train 10
between the axle 41, which is a first axle, monitored for
25 detection by the velocity sensor 31, and the axle 47, which
is a second axle, monitored for detection by the velocity
sensor 32.
[0017] An operation of the train control device 20 to
determine whether a slip or a slide has occurred on the
30 train 10 will next be described. The control unit 23 of
the train control device 20 calculates, as described above,
a pulse ratio between the number of first pulses detected
by the velocity sensor 31 and the number of second pulses
8
detected by the velocity sensor 32 during a time period in
which the train 10 travels the axle-to-axle distance. Note
that it is assumed that the train control device 20 stores,
in the control unit 23 or in the storage unit 22, a pulse
5 ratio in normal operation when neither a slip nor a slide
is occurring on the train 10. The control unit 23
calculates the pulse ratio, and compares the calculated
pulse ratio with the pulse ratio in normal operation,
periodically while the train 10 is running. The control
10 unit 23 determines that a slip or a slide has occurred on
the train 10 when a difference is determined to be greater
than or equal to a given threshold based on the comparison
of the calculated pulse ratio with the pulse ratio in
normal operation. Note that the pulse ratio in normal
15 operation may hereinafter be referred to as normaloperation pulse ratio.
[0018] A slip or a slide occurs on the train 10, in
general, when a foreign matter such as water, oil, or a
fallen leaf exists on rails (not illustrated) with which
20 the wheels 51 to 58 and 61 to 68 of the train 10 are to
come into contact, thereby reducing friction force between
the wheels 51 to 58 and 61 to 68 and the rails. Thus, a
slip or a slide occurs on the train 10 when the wheels 51
to 58 and 61 to 68 reach specific points on the rails. The
25 velocity sensors 31 and 32 are accordingly installed on the
train 10 to be spaced sufficiently apart from each other.
This creates, on the train 10, a situation in which even
when a slip or a slide has occurred on the wheels 51 and 61
positioned forward in the travel direction of the train 10
30 and attached to the axle 41 monitored for detection by the
velocity sensor 31, neither a slip nor a slide has yet
occurred on the wheels 57 and 67 positioned rearward in the
travel direction of the train 10 and attached to the axle
9
47 monitored for detection by the velocity sensor 32. The
following description refers to the wheels 51 and 61 as
front wheels, and the wheels 57 and 67 as rear wheels. The
axle 41 has the front wheels attached thereto, which wheels
5 are the wheels 51 and 61 provided on the train 10 at a
forward position in the travel direction of the train 10.
The axle 47 has the rear wheels attached thereto, which
wheels are the wheels 57 and 67 provided on the train 10 at
a rearward position in the travel direction of the train 10.
10 [0019] That is, the train 10 operates such that even
when a slip or a slide has occurred on the front wheels,
neither a slip nor a slide occurs on the rear wheels before
the train 10 travels axle-to-axle distance. The control
unit 23 of the train control device 20 thus constantly
15 makes a comparison on the number of pulses that have been
generated on the axle 41 having the front wheels attached
thereto during a measurement period from the present time,
where the measurement period is a time period in which
pulses are generated as many as the number equivalent to
20 the axle-to-axle distance, on the axle 47 having the rear
wheels attached thereto. The control unit 23 compares the
result of comparison, i.e., the pulse ratio, with the pulse
ratio in normal operation, and can thus determine whether a
slip or a slide has occurred on the train 10.
25 [0020] FIG. 2 is a diagram illustrating an example of
pulses detected by the velocity sensors 31 and 32 when
neither a slip nor a slide is occurring on the train 10
according to the first embodiment. In FIG. 2, the upper
part illustrates the first pulses detected by the velocity
30 sensor 31, and the lower part illustrates the second pulses
detected by the velocity sensor 32. In addition, the
horizontal axes in FIG. 2 represent time. FIG. 2
illustrates a case in which a difference between the pulse
10
ratio in a measurement period from the present time and a
given pulse ratio in normal operation is less than a
threshold, where the measurement period is a time period in
which pulses are generated as many as the number equivalent
5 to the axle-to-axle distance, on the axle 47 having the
rear wheels attached thereto. Note that FIG. 2
schematically illustrates the pulses for simplicity of
illustration, and much more pulses are actually detected in
the measurement period. This also applies to the diagrams
10 referred to in the following description.
[0021] FIG. 3 is a diagram illustrating an example of
pulses detected by the velocity sensors 31 and 32 when a
slip or a slide is occurring on the train 10 according to
the first embodiment. In FIG. 3, the upper part
15 illustrates the first pulses detected by the velocity
sensor 31, and the lower part illustrates the second pulses
detected by the velocity sensor 32. In addition, the
horizontal axes in FIG. 3 represent time. FIG. 3
illustrates a case in which the difference between the
20 pulse ratio in the measurement period from the present time
and the given pulse ratio in normal operation is greater
than or equal to a threshold, where the measurement period
is a time period in which pulses are generated as many as
the number equivalent to the axle-to-axle distance, on the
25 axle 47 having the rear wheels attached thereto.
[0022] As described above, the control unit 23 compares
the pulse ratio in each of the measurement periods with the
given pulse ratio in normal operation, and can thus
determine whether a slip or a slide has occurred on the
30 train 10. In this operation, the control unit 23 detects
the number of first pulses and the number of second pulses,
that is, the control unit 23 calculates the pulse ratio,
for each of the measurement periods, where the multiple
11
consecutive measurement periods partially overlap each
other as illustrated in FIGs. 2 and 3, rather than a next
measurement period starts after one measurement period ends.
The start time of each measurement period is shifted by,
5 for example, about 100 milliseconds or 200 milliseconds.
This period of about 100 milliseconds or 200 milliseconds
is the interval of calculation of the pulse ratio, that is,
of checking the pulse ratio, in the measurement period
performed by the control unit 23. That is, the control
10 unit 23 checks the pulse ratio at an interval shorter than
the time period in which the train 10 travels the axle-toaxle distance. This enables the control unit 23 to
determine whether a slip or a slide has occurred on the
train 10 using pulses detected by the velocity sensors 31
15 and 32 while the train 10 travels the axle-to-axle distance,
at an interval shorter than the measurement period in which
the train 10 travels the axle-to-axle distance. When the
axle-to-axle distance is sufficiently longer than a
distance equivalent to the pulse spacing of detection of
20 the first pulses and the second pulses, an error that may
occur in the pulse ratio calculated by the control unit 23
will be very small even when an error corresponding to a
single pulse has occurred in the number of pulses included
in each measurement period.
25 [0023] Note that when a slip or a slide has occurred on
the train 10 as illustrated in FIG. 3, the control unit 23
is reasonably expected to determine that a slip or a slide
has occurred on the train 10 for multiple consecutive
measurement periods. The control unit 23 may accordingly
30 determine whether a slip or a slide has actually occurred
based on the number of consecutive determinations that a
slip or a slide of the train 10 has occurred. FIG. 4 is a
diagram illustrating an example of pulses detected by the
12
velocity sensors 31 and 32 when a slip or a slide has
occurred for a short time period on the train 10 according
to the first embodiment. In FIG. 4, the upper part
illustrates the first pulses detected by the velocity
5 sensor 31, and the lower part illustrates the second pulses
detected by the velocity sensor 32. In addition, the
horizontal axes in FIG. 4 represent time. FIG. 5 is a
diagram illustrating an example, as a comparative example,
in which the measurement periods for counting pulses
10 detected by the velocity sensors 31 and 32 are independent
of each other. FIG. 5 assumes a case in which the
measurement periods for counting the number of pulses are
independent of each other, i.e., a case in which a next
measurement period starts after one measurement period ends.
15 In FIG. 5, each measurement period is a time period
corresponding to the shift amount of each measurement
period illustrated in FIG. 4. In such case, an unexpected,
sudden pulse detected as a first pulse in a certain
measurement period may be identified as a false detection
20 of the velocity sensor 31 because no unexpected, sudden
pulse is detected in the next measurement period.
[0024] In contrast, the control unit 23 in FIG. 4 is
capable of determining that a slip or a slide has occurred
on the train 10 when a slip or a slide has occurred on the
25 train 10 even for a short time, based on the pulse ratios
in multiple measurement periods. Thus, when the number of
consecutive determinations that a slip or a slide of the
train 10 has occurred is greater than or equal to a given
number of times, the control unit 23 determines that a slip
30 or a slide has actually occurred on the train 10. When the
number of consecutive determinations that a slip or a slide
of the train 10 has occurred is less than the given number
of times, the control unit 23 determines that neither a
13
slip nor a slide has actually occurred on the train 10.
[0025] In addition, use of the first pulses detected by
the velocity sensor 31 and the second pulses detected by
the velocity sensor 32 enables the control unit 23 to
5 subsequently detect a slip or a slide that has occurred
even for a short time. FIG. 6 is a first diagram
illustrating transition of a slip-or-slide detection state
of the train 10 according to the first embodiment. FIG. 6
illustrates a state similar to the state in the case of FIG.
10 2, and neither a slip nor a slide has been detected on
neither of the first pulses from the velocity sensor 31 and
the second pulses from the velocity sensor 32. FIG. 7 is a
second diagram illustrating transition of the slip-or-slide
detection state of the train 10 according to the first
15 embodiment. FIG. 7 illustrates a state in which the wheels
51 and 61, attached to the axle 41 monitored for detection
by the velocity sensor 31, have passed over a cause of a
slip or a slide, thereby causing a pulse irregularity due
to a slip or a slide to occur on the first pulses from the
20 velocity sensor 31. In FIG. 7, the wheels 57 and 67,
attached to the axle 47 monitored for detection by the
velocity sensor 32, have not yet passed over the cause of a
slip or a slide, and are thus in a state similar to the
state in the case of FIG. 6.
25 [0026] FIG. 8 is a third diagram illustrating transition
of the slip-or-slide detection state of the train 10
according to the first embodiment. FIG. 8 illustrates a
state in which, similarly to FIG. 7, the wheels 51 and 61,
attached to the axle 41 monitored for detection by the
30 velocity sensor 31, have passed over the cause of a slip or
a slide, thereby causing a pulse irregularity due to a slip
or a slide to occur on the first pulses from the velocity
sensor 31 because the train 10 is within the measurement
14
period of the velocity sensor 31. In FIG. 8, the wheels 57
and 67, attached to the axle 47 monitored for detection by
the velocity sensor 32, have not yet passed over the cause
of a slip or a slide, and are thus in a state similar to
5 the state in the case of FIG. 6. FIG. 9 is a fourth
diagram illustrating transition of the slip-or-slide
detection state of the train 10 according to the first
embodiment. FIG. 9 illustrates a state in which the train
10 has traveled the axle-to-axle distance since the wheels
10 51 and 61, attached to the axle 41 monitored for detection
by the velocity sensor 31, passed over the cause of a slip
or a slide, in which state the irregularity of pulses due
to a slip or a slide has been resolved on the first pulses
from the velocity sensor 31. On the other hand, FIG. 9
15 also illustrates a state in which the wheels 57 and 67,
attached to the axle 47 monitored for detection by the
velocity sensor 32, have passed over the cause of a slip or
a slide, thereby causing a pulse irregularity due to a slip
or a slide to occur on the second pulses from the velocity
20 sensor 32. As described above, use of a section equivalent
to the axle-to-axle distance for detecting pulses by the
velocity sensors 31 and 32 allows the control unit 23 to
continue to subsequently detect the cause of a slip or a
slide for a certain time after the situation of FIG. 9.
25 That is, the control unit 23 is capable of subsequently
detecting a slip or a slide using the velocity sensor 32
even after the velocity sensor 31 can no longer detect a
slip or a slide.
[0027] Note that the train control device 20 may store a
30 predetermined pulse ratio in normal operation in the
control unit 23 or in the storage unit 22, or may calculate
a pulse ratio in normal operation by the control unit 23
during coasting operation of the train 10 during which
15
neither a slip nor a slide is occurring on the train 10,
and store the pulse ratio in normal operation in the
control unit 23 or in the storage unit 22. In the case in
which the control unit 23 calculates the pulse ratio in
5 normal operation, the control unit 23 may periodically
calculate and update the pulse ratio in normal operation.
[0028] An operation of the train control device 20 will
next be described using a flowchart. FIG. 10 is a
flowchart illustrating an operation of the train control
10 device 20 according to the first embodiment. In the train
control device 20, the acquisition unit 21 obtains a first
pulse from the velocity sensor 31, and obtains a second
pulse from the velocity sensor 32 (step S11). The
acquisition unit 21 stores the first pulse and the second
15 pulse in the storage unit 22 (step S12). The control unit
23 reads the number of first pulses and the number of
second pulses included in the measurement period at the
present time among the first pulses and the second pulses
stored in the storage unit 22 (step S13). The control unit
20 23 calculates a pulse ratio using the number of first
pulses and the number of second pulses that have been read
(step S14).
[0029] The control unit 23 compares the calculated pulse
ratio with the pulse ratio in normal operation (step S15).
25 When a difference between the calculated pulse ratio and
the pulse ratio in normal operation is less than a
threshold (step S15: Yes), the control unit 23 determines
that neither a slip nor a slide has occurred on the train
10 (step S16). When the difference between the calculated
30 pulse ratio and the pulse ratio in normal operation is
greater than or equal to the threshold (step S15: No), the
control unit 23 counts the number of times the difference
between the calculated pulse ratio and the pulse ratio in
16
normal operation is consecutively greater than or equal to
the threshold (step S17). When the number of times the
difference is consecutively greater than or equal to the
threshold is less than a given number of times (step S17:
5 No), the control unit 23 determines that neither a slip nor
a slide has occurred on the train 10 (step S16). When the
number of times the difference is consecutively greater
than or equal to the threshold is greater than or equal to
the given number of times (step S17: Yes), the control unit
10 23 determines that a slip or a slide has occurred on the
train 10 (step S18). The train control device 20
periodically performs the operation of the flowchart
illustrated in FIG. 10 at an interval equivalent to the
shift amount of the measurement period described above,
15 i.e., an interval of about 100 milliseconds or 200
milliseconds.
[0030] A hardware configuration of the train control
device 20 will next be described. In the train control
device 20, the acquisition unit 21 is an interface such as
20 a communication device. The storage unit 22 is a memory.
The control unit 23 is implemented in a processing
circuitry. The processing circuitry may be a processor
that executes a program stored in a memory and the memory,
or may be a dedicated hardware element.
25 [0031] FIG. 11 is a diagram illustrating an example of a
processing circuitry 90 included in the train control
device 20 according to the first embodiment when the
processing circuitry 90 includes a processor 91 and a
memory 92. When the processing circuitry 90 includes the
30 processor 91 and the memory 92, each functionality of the
processing circuitry 90 of the train control device 20 is
implemented in software, firmware, or a combination of
software and firmware. The software or firmware is
17
described in the form of a program, and is stored in the
memory 92. The processing circuitry 90 provides each
functionality in such a manner that the processor 91 reads
and executes a program stored in the memory 92. That is,
5 the processing circuitry 90 includes the memory 92 for
storing programs that cause the processing of the train
control device 202 to be performed. In addition, it can
also be said that these programs cause a computer to
perform a procedure and a method of the train control
10 device 20.
[0032] In this respect, the processor 91 may be a
central processing unit (CPU), a processing unit, a
computing unit, a microprocessor, a microcomputer, a
digital signal processor (DSP), or the like. In addition,
15 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), or an electrically EPROM (EEPROM)
(registered trademark); a magnetic disk, a flexible disk,
20 an optical disk, a compact disc, a MiniDisc, a digital
versatile disc (DVD), or the like.
[0033] FIG. 12 is a diagram illustrating an example of a
processing circuitry 93 included in the train control
device 20 according to the first embodiment when the
25 processing circuitry 93 includes a dedicated hardware
element. When the processing circuitry 93 includes a
dedicated hardware element, the processing circuitry 93
illustrated in FIG. 12 is, for example, a single circuit, a
set of multiple circuits, a programmed processor, a
30 parallel programmed processor, an application specific
integrated circuit (ASIC), a field programmable gate array
(FPGA), or a combination thereof. Each functionality of
the train control device 20 may be implemented in the
18
processing circuitry 93 on a function-by-function basis, or
the functionalities may together be implemented in the
processing circuitry 93.
[0034] Note that each functionality of the train control
5 device 20 may be implemented partially in a dedicated
hardware element and partially in software or firmware.
Thus, the processing circuitry can provide each
functionality described above in a dedicated hardware
element, software, firmware, or a combination thereof.
10 [0035] As described above, according to this embodiment,
the train control device 20 calculates a pulse ratio of
pulses detected by the velocity sensors 31 and 32 in a
measurement period, which is a time period in which the
train 10 travels the axle-to-axle distance between the
15 axles 41 and 47 monitored for detection by the velocity
sensors 31 and 32 of the train 10. The train control
device 20 then compares the calculated pulse ratio with the
pulse ratio in normal operation to determine whether a slip
or a slide has occurred on the train 10. This enables the
20 train control device 20 to detect a slip or a slide
occurring on the train 10 with high accuracy while avoiding
a long detection period.
[0036] Second Embodiment.
A second embodiment will be described with respect to
25 a case in which the control unit 23 of the train control
device 20 corrects the wheel diameter of a wheel of the
train 10.
[0037] In the second embodiment, the train 10 and the
train control device 20 are configured similarly to the
30 train 10 and the train control device 20 in the first
embodiment illustrated in FIG. 1. In normal running
control of the train 10, the train control device 20
estimates the speed of the train 10, the travel distance of
19
the train 10, and the like using the pulses obtained from
the velocity sensors 31 and 32. Estimation of the speed of
the train 10, the travel distance of the train 10, and the
like requires information of wheel diameters of the wheels
5 51 and 61, attached to the axle 41 monitored for detection
by the velocity sensor 31, and of wheel diameters of the
wheels 57 and 67, attached to the axle 47 monitored for
detection by the velocity sensor 32. However, the wheels
51 to 58 and 61 to 68 of the train 10 undergo a decrease in
10 the wheel diameter due to gradual wear caused by running of
the train 10. An incorrect value of the wheel diameter may
cause a large error in the speed of the train 10, the
travel distance of the train 10, and the like that are
estimated by the train control device 20. Thus, when the
15 foregoing pulse ratio has changed in coasting operation of
the train 10, during which neither a slip or a slide occurs
on the train 10, the control unit 23 of the train control
device 20 determines that one of the wheels has worn, and
provides control to correct the wheel diameter of the
20 applicable wheel. Note that for simplicity of illustration,
the wheels 51 to 58 and 61 to 68 on the train 10 are
assumed to be of a same type.
[0038] FIG. 13 is a diagram illustrating an illustrative
image of wheel diameters of wheels provided on the train 10
25 according to the second embodiment. For simplicity of
illustration, the following description designates the
wheels 51 and 61, attached to the axle 41 monitored for
detection by the velocity sensor 31, as wheel A, and the
wheels 57 and 67, attached to the axle 47 monitored for
30 detection by the velocity sensor 32, as wheel B. In
addition, the initial wheel diameter at the present time of
wheel A is designated R_a. The initial wheel diameter at
the present time of wheel B is designated R_b. The wheel
20
diameter ratio of the initial wheel diameter R_a of wheel A
to the initial wheel diameter R_b of wheel B is designated
“R_a/R_b=Ratio0”. In this respect, the initial wheel
diameter R_a is greater than the initial wheel diameter R_b,
5 meaning that Ratio0>1. Note that the wheel diameter ratio
Ratio0 can be expressed as “Ratio0=number of second
pulses/number of first pulses” using the number of first
pulses and the number of second pulses described above.
That is, “initial wheel diameter R_a”:“initial wheel
10 diameter R_b”=“the number of second pulses”:“the number of
first pulses”.
[0039] A case will next be described in which a wheel
diameter ratio Ratio1 after a change exceeds the initial
wheel diameter ratio Ratio0. FIG. 14 is a diagram
15 illustrating an illustrative image of a case in which wheel
B provided on the train 10 according to the second
embodiment has worn. Because the wheel diameter will never
increase unless the wheel is exchanged, the control unit 23
corrects the wheel diameter of wheel B when Ratio1>Ratio0.
20 The new wheel diameter R_b1 after correction can be
calculated by “R_b1=R_a×(1/Ratio1)”. In the case of
Ratio1>Ratio0, the control unit 23 may use a threshold to
determine that Ratio1=Ratio0, and determine not to correct
the wheel diameter of wheel B, when the difference is less
25 than the threshold.
[0040] A case will next be described in which the wheel
diameter ratio Ratio1 after a change falls below the
initial wheel diameter ratio Ratio0. FIG. 15 is a diagram
illustrating an illustrative image of a case in which wheel
30 A provided on the train 10 according to the second
embodiment has worn. Because the wheel diameter will never
increase unless the wheel is exchanged, the control unit 23
corrects the wheel diameter of wheel A when Ratio1Ratio0
10 as an example, but is also applicable to the case of
Ratio1