FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
SLIP/SKID DISCRIMINATION DEVICE, BRAKE CONTROL SYSTEM, AND
SLIP/SKID DISCRIMINATION METHOD;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Title of Invention
SLIP/SKID DISCRIMINATION DEVICE, BRAKE CONTROL SYSTEM, AND
SLIP/SKID DISCRIMINATION METHOD
5
Technical Field
[0001] The present disclosure relates to a slip-and-skid determining device, a brake
control system, and a slip-and-skid determining method.
Background Art
10 [0002] A traveling railway vehicle may have a slip or a skid of wheels when the
adhesive force between the wheels and the rails decreases. A slip or a skid of any wheel
can disable the railway vehicle from traveling at a speed corresponding to a target
acceleration. Thus, it is preferable to determine occurrence of a slip or skid and
moderate acceleration or deceleration of the railway vehicle to achieve re-adhesion of the
15 wheel to the rail. Patent Literature 1 describes a brake control system as an example
device to determine occurrence of a slip or a skid.
Citation List
Patent Literature
[0003] Patent Literature 1: Unexamined Japanese Patent Application Publication
20 No. 2008-143365
Summary of Invention
Technical Problem
[0004] The brake control system described in Patent Literature 1 determine, based
on a rapid decrease in the axle speed that is caused by the skid, whether any skid occurs.
25 More specifically, the brake control system uses, as a reference axle speed, the maximum
value of the axle speeds of the four axles in each vehicle. When a difference between
the axle speed of any axle and the reference axle speed is greater than or equal to a
3
threshold, the brake control system determines that the skid occurs in the wheel attached
to the axle for which the difference is greater than or equal to the threshold.
[0005] When the wheels attached to all the four axles in a single vehicle skid, the
axle speed of each of these axles decreases rapidly, and then, the reference axle speed
5 rapidly decreases as well. In this state, the difference between the axle speed of each of
the axles and the reference axle speed does not increase. Thus, when the wheels
attached to all axles skid, the brake control system described in Patent Literature 1 cannot
detect the skid. Similarly, in detecting a slip of any wheel, this issue also arises when
the wheels attached to all the four axles in the single vehicle slip.
10 [0006] Under such circumstances, an objective of the present disclosure is to
provide a slip-and-skid determining device, a brake control system, and a slip-and-skid
determining method that determines whether any slip or skid of any wheel occurs when
the wheels attached to all axles in a single vehicle slip or skid.
Solution to Problem
15 [0007] To achieve the above objective, a slip-and-skid determining device
according to an aspect of the present disclosure includes an axle speed decider, a
reference axle speed decider, and a determiner. The axle speed decider decides, for each
of a plurality of axles in a vehicle of one or more vehicles included in a railway vehicle,
an axle speed changeable based on a rotational speed of a wheel attached to each of the
20 plurality of axles in the vehicle. The reference axle speed decider decides, based on the
axle speed of each of the plurality of axles in the vehicle and a physical quantity
changeable during travel of the railway vehicle, a reference axle speed in the vehicle.
The determiner determines, based on comparison between the axle speed and the
reference axle speed, whether any slip or skid of the wheel occurs.
25 Advantageous Effects of Invention
[0008] The slip-and-skid determining device according to the above aspect of the
present disclosure decides the reference axle speed based on the axle speed and the
4
physical quantity changeable during travel of the railway vehicle, and determines, based
on comparison between the axle speed and the reference axle speed, whether any slip or
skid of a wheel occurs in the vehicle. The slip-and-skid determining device can thus
determine whether any slip or skid of any wheel occurs when wheels attached to all axles
5 in a single vehicle slip or skid.
Brief Description of Drawings
[0009] FIG. 1 illustrates a railway vehicle provided with a slip-and-skid
determining device according to Embodiment 1;
FIG. 2 is a block diagram illustrating a brake control device in Embodiment 1;
10 FIG. 3 is a block diagram illustrating the slip-and-skid determining device
according to Embodiment 1;
FIG. 4 illustrates a hardware configuration of the brake control device and the slipand-skid determining device according to Embodiment 1;
FIG. 5 is a flowchart illustrating exemplary steps of a skid determining process
15 executed by the slip-and-skid determining device according to Embodiment 1;
FIG. 6 illustrates example changes in an axle speed and a reference axle speed in a
comparative example;
FIG. 7 illustrates example changes in an axle speed and a reference axle speed in
Embodiment 1;
20 FIG. 8 illustrates a railway vehicle provided with a slip-and-skid determining
device according to Embodiment 2;
FIG. 9 is a block diagram illustrating the slip-and-skid determining device
according to Embodiment 2;
FIG. 10 is a flowchart illustrating exemplary steps of a skid determining process
25 executed by the slip-and-skid determining device according to Embodiment 2;
FIG. 11 is a block diagram illustrating a slip-and-skid determining device
according to Embodiment 3;
5
FIG. 12 is a block diagram illustrating a reference axle speed decider in
Embodiment 3;
FIG. 13 illustrating a railway vehicle provided with a slip-and-skid determining
device according to Embodiment 4;
5 FIG. 14 is a block diagram illustrating the slip-and-skid determining device
according to Embodiment 4;
FIG. 15 is a flowchart illustrating exemplary steps of a skid determining process
executed by the slip-and-skid determining device according to Embodiment 4;
FIG. 16 is a block diagram illustrating a power converter according to
10 Embodiment 5;
FIG. 17 is a block diagram illustrating a slip-and-skid determining device
according to Embodiment 5;
FIG. 18 is a block diagram illustrating a reference axle speed decider in
Embodiment 5;
15 FIG. 19 is a flowchart illustrating exemplary steps of a slip-and-skid determining
process executed by the slip-and-skid determining device according to Embodiment 5;
FIG. 20 illustrates example changes in an axle speed and a reference axle speed in
Embodiment 5;
FIG. 21 is a block diagram illustrating a reference axle speed decider in a first
20 modification of an embodiment;
FIG. 22 is a block diagram illustrating a reference axle speed decider in a second
modification of an embodiment; and
FIG. 23 illustrates a modification of a hardware configuration of a slip-and-skid
determining device.
25 Description of Embodiments
[0010] A slip-and-skid determining device, a brake control system, and a slip-andskid determining method according to one or more embodiments of the present disclosure
6
are described in detail below with reference to the accompanying drawings. In the
drawings, the components identical or corresponding to each other are provided with the
same reference symbol.
[0011] Embodiment 1
5 A slip-and-skid determining device according to Embodiment 1 mounted on a
railway vehicle including one or more vehicles is described. The slip-and-skid
determining device determines whether any slip or skid of any wheel of a railway vehicle
occurs, the slip or skid being caused by decrease in the adhesive force between the wheel
and a rail.
10 [0012] A railway vehicle 1 illustrated in FIG. 1 includes a vehicle 100 and a vehicle
200 that are connected to each other. For example, the vehicle 100 is a motor coach
incorporating an electric motor, which is not illustrated, and the vehicle 200 is a trailer
coach without an electric motor.
[0013] The vehicle 100 includes a master controller 5 that outputs an operation
15 command in response to an operation by an operator, a load detector 11 that detects a
load on the vehicle 100, and a brake control system 10 that determines whether any slip
or a skid of any wheel of the vehicle 100 occurs and controls the brake of the vehicle 100.
The brake control system 10 includes a brake control device 12 that controls the brake of
the vehicle 100 and a slip-and-skid determining device 13 that determines whether any
20 slip or a skid of any wheel of the vehicle 100 occurs.
[0014] A bogie supporting the vehicle body of the vehicle 100 is provided with the
electric motor and axles 14a, 14b, 14c, and 14d that rotate with a rotational force
transmitted from the electric motor. A wheel 15a is attached to each end of the axle 14a
and integrally rotates with the axle 14a. A wheel 15b is attached to each end of the axle
25 14b and integrally rotates with the axle 14b. A wheel 15c is attached to each end of the
axle 14c and integrally rotates with the axle 14c. A wheel 15d is attached to each end of
the axle 14d and integrally rotates with the axle 14d.
7
[0015] The vehicle 100 includes speed detectors 16a, 16b, 16c, and 16d that detect
the rotational speeds of the respective wheels 15a, 15b, 15c, and 15d. The vehicle 100
further includes, as mechanical brake devices, brake blocks 17a, 17b, 17c, and 17d that
come in contact with the respective wheels 15a, 15b, 15c, and 15d to generate a brake
5 force, and brake cylinders 18a, 18b, 18c, and 18d attached to the respective brake blocks
17a, 17b, 17c, and 17d to receive a fluid supplied from the brake control device 12. The
vehicle 100 decelerates when the brake blocks 17a, 17b, 17c, and 17d as frictional
members are pressed against the wheels 15a, 15b, 15c, and 15d as rotors rotating during
travel of the railway vehicle 1.
10 [0016] The vehicle 100 further includes anti-skid valves 19a, 19b, 19c, and 19d that
discharge the fluid supplied to the respective brake cylinders 18a, 18b, 18c, and 18d.
[0017] The vehicle 200 includes a load detector 21 that detects a load on the vehicle
200 and a brake control system 20 that determines whether any slip or skid of any wheel
of the vehicle 200 occurs and controls the brake of the vehicle 200. The brake control
15 system 20 includes a brake control device 22 that controls the brake of the vehicle 200,
and a slip-and-skid determining device 23 that determines whether any slip or skid of any
wheel of the vehicle 200 occurs.
[0018] A bogie supporting the vehicle body of the vehicle 200 is provided with
axles 24a, 24b, 24c, and 24d. A wheel 25a is attached to each end of the axle 24a and
20 integrally rotates with the axle 24a. A wheel 25b is attached to each end of the axle 24b
and integrally rotates with the axle 24b. A wheel 25c is attached to each end of the axle
24c and integrally rotates with the axle 24c. A wheel 25d is attached to each end of the
axle 24d and integrally rotates with the axle 24d.
[0019] The vehicle 200 includes speed determiners 26a, 26b, 26c, and 26d that
25 detect the rotational speeds of the respective wheels 25a, 25b, 25c, and 25d. The vehicle
200 further includes, as mechanical brake devices, brake blocks 27a, 27b, 27c, and 27d
that come in contact with the respective wheels 25a, 25b, 25c, and 25d to generate a
8
brake force, and brake cylinders 28a, 28b, 28c, and 28d attached to the respective brake
blocks 27a, 27b, 27c, and 27d to receive a fluid supplied from the brake control device
22. The vehicle 200 decelerates when the brake blocks 27a, 27b, 27c, and 27d as
frictional members are pressed against the wheels 25a, 25b, 25c, and 25d as rotors
5 rotating during the travel of the railway vehicle 1.
[0020] The vehicle 200 further includes anti-skid valves 29a, 29b, 29c, and 29d that
discharge the fluid supplied to the respective brake cylinders 28a, 28b, 28c, and 28d.
[0021] FIG. 1 illustrates air pipes with bold solid lines, and flows of electric signals
transmitted and received between components in the vehicles 100 and 200 with solid
10 arrows. The same applies to the subsequent figures.
[0022] As illustrated with the bold solid lines in FIG. 1, the fluid is supplied from a
fluid source which is not illustrated, compressed by the brake control device 12, and
supplied to the brake cylinders 18a, 18b, 18c, and 18d. The fluid is, for example, air.
[0023] A piston in the brake cylinder 18a slides in response to the pressure of the
15 fluid in the brake cylinder 18a, causing the brake block 17a attached to the piston to move
toward or away from the wheel 15a. Similarly, a piston in the brake cylinder 18b slides
in response to the pressure of the fluid in the brake cylinder 18b, causing the brake block
17b attached to the piston to move toward or away from the wheel 15b. Similarly, a
piston in the brake cylinder 18c slides in response to the pressure of the fluid in the brake
20 cylinder 18c, causing the brake block 17c attached to the piston to move toward the
wheel 15b or move away from the wheel 15c. Similarly, a piston in the brake cylinder
18d slides in response to the pressure of the fluid in the brake cylinder 18d, causing the
brake block 17d attached to the piston to move toward or away from the wheel 15d.
[0024] The brake blocks 17a, 17b, 17c, and 17d come in contact with the respective
25 wheels 15a, 15b, 15c, and 15d to restrict rotation of the wheels 15a, 15b, 15c, and 15d,
generating the brake force.
[0025] The fluid is supplied from the fluid source, compressed by the brake control
9
device 22, and supplied to the brake cylinders 28a, 28b, 28c, and 28d. A piston in the
brake cylinder 28a slides in response to the pressure of the fluid in the brake cylinder 28a,
causing the brake block 27a attached to the piston to move toward or away from the
wheel 25a. Similarly, a piston in the brake cylinder 28b slides in response to the
5 pressure of the fluid in the brake cylinder 28b, causing the brake block 27b attached to the
piston to move toward or away from the wheel 25b. Similarly, a piston in the brake
cylinder 28c slides in response to the pressure of the fluid in the brake cylinder 28c,
causing the brake block 27c attached to the piston to move toward the wheel 25b or move
away from the wheel 25c. Similarly, a piston in the brake cylinder 28d slides in
10 response to the pressure of the fluid in the brake cylinder 28d, causing the brake block
27d attached to the piston to move toward or away from the wheel 25d.
[0026] The brake blocks 27a, 27b, 27c, and 27d come in contact with the wheels
25a, 25b, 25c, and 25d to restrict rotation of the wheels 25a, 25b, 25c, and 25d,
generating the brake force.
15 [0027] The master controller 5 is installed on, for example, a driver's cab, and
outputs the operation command in response to the operation by the operator to the brake
control devices 12 and 22 and to the slip-and-skid determining devices 13 and 23. The
operation command may be a powering command for accelerating the railway vehicle 1,
a braking command for decelerating the railway vehicle 1, or a coasting command for
20 causing a coasting operation of the railway vehicle 1.
[0028] The load detector 11 detects a load on the vehicle 100 based on a change in
the pressure of an air spring attached to the bogie supporting the vehicle body of the
vehicle 100, and transmits the detected load on the vehicle 100 to the brake control device
12. Similarly, the load detector 21 detects a load on the vehicle 200 based on a change
25 in the pressure of an air spring attached to the bogie supporting the vehicle body of the
vehicle 200, and transmits the detected load on the vehicle 200 to the brake control device
22.
10
[0029] The brake control devices 12 and 22 have the same structure. The brake
control device 12 is thus described with reference to FIG. 2. The brake control device
12 includes a target brake force decider 41 that decides a target brake force as a target
value for the brake force of the vehicle 100, and a target pressure decider 42 that decides
5 a target pressure as a target value for the pressure of the fluid in the brake cylinders 18a,
18b, 18c, and 18d in accordance with the target brake force. The brake control device
12 further includes an output valve 43 that compresses a fluid supplied from a fluid
source 81 in accordance with the target pressure and supplies the compressed air to the
brake cylinders 18a, 18b, 18c, and 18d through the anti-skid valves 19a, 19b, 19c, and
10 19d.
[0030] The brake control device 12 further includes a pressure sensor 44 that
measures a value for the pressure of the fluid output from the output valve 43, and a readhesion controller 47 that adjusts the opening degrees of the anti-skid valves 19a, 19b,
19c, and 19d in accordance with a determination result received from the slip-and-skid
15 determining device 13.
[0031] When the operation command acquired from the master controller 5
includes a braking command, the target brake force decider 41 decides the target brake
force in accordance with a target deceleration indicated by the braking command and the
load on the vehicle 100 acquired from the load detector 11. More specifically, the target
20 brake force decider 41 outputs, as the target brake force, a value acquired by multiplying
the target deceleration by the load on the vehicle 100 to the target pressure decider 42.
[0032] The target pressure decider 42 decides, based on a friction coefficient of a
contact surface between each of the brake blocks 17a, 17b, 17c, and 17d and the
corresponding wheel 15a, 15b, 15c, or 15d as well as the target braking force, a target
25 pressing force as a target value of pressing force for pressing each of the brake blocks
17a, 17b, 17c, and 17d to the corresponding wheel 15a, 15b, 15c, or 15d. The target
pressure decider 42 prestores information about the friction coefficients of contact
11
surfaces between the brake blocks 17a, 17b, 17c, and 17d and the wheels 15a, 15b, 15c,
and 15d. The target pressure decider 42 decides the target pressure as a target value for
the pressure of the fluid in the brake cylinders 18a, 18b, 18c, and 18d to achieve the target
pressing force.
5 [0033] More specifically, to acquire the target pressure, the target pressure decider
42 divides the target pressing force by the area of a surface perpendicular to a direction in
which the pistons of the brake cylinders 18a, 18b, 18c, and 18d slide. The target
pressure decider 42 performs feedback control to adjust the target pressure acquired
through the above calculation based on the measurement value from the pressure sensor
10 44. The target pressure decider 42 transmits the adjusted target pressure to the output
valve 43.
[0034] The output valve 43 includes an electro-pneumatic conversion valve 45 that
adjusts the pressure of the fluid supplied from the fluid source 81 in accordance with the
target pressure and outputs the pressure-adjusted fluid, and a relay valve 46 that
15 compresses the fluid supplied from the fluid source 81 in accordance with the output
from the electro-pneumatic conversion valve 45 and outputs the compressed fluid. The
electro-pneumatic conversion valve 45 adjusts the pressure of the fluid supplied from the
fluid source 81 in accordance with the target pressure indicated by an electric signal
transmitted from the target pressure decider 42, and outputs the pressure-adjusted fluid to
20 the relay valve 46. The relay valve 46 receives the pressure of the fluid output from the
electro-pneumatic conversion valve 45 as a command pressure, compresses the fluid
supplied from the fluid source 81 in accordance with the command pressure, and supplies
the compressed fluid to the brake cylinders 18a, 18b, 18c, and 18d through the anti-skid
valves 19a, 19b, 19c, and 19d.
25 [0035] The re-adhesion controller 47 adjusts the opening degrees of the anti-skid
valves 19a, 19b, 19c, and 19d in accordance with the determination result received from
the slip-and-skid determining device 13. More specifically, when the slip-and-skid
12
determining device 13 determines that a skid of any of the wheels 15a, 15b, 15c, and 15d
occurs, the re-adhesion controller 47 opens the corresponding anti-skid valve 19a, 19b,
19c, or 19d corresponding the skid wheel 15a, 15b, 15c, or 15d. When, for example, the
slip-and-skid determining device 13 determines that a skid of the wheel 15a occurs, the
5 re-adhesion controller 47 opens the anti-skid valve 19a to discharge the fluid from the
brake cylinder 18a to which the brake block 17a for restricting rotation of the wheel 15a
is attached to. When the anti-skid valve 19a is open, the fluid in the brake cylinder 18a
is discharged, reducing the pressure of the fluid in the brake cylinder 18a. This reduces
the brake force for the wheel 15a, and thus achieves re-adhesion of the wheel 15a to the
10 rail.
[0036] The slip-and-skid determining devices 13 and 23 have the same structure.
The slip-and-skid determining device 13 that determines whether any skid occurs is thus
described with reference to FIG. 3. The slip-and-skid determining device 13 includes an
axle speed decider 51 that decides the axle speed of each of the axles 14a, 14b, 14c, and
15 14d of the vehicle 100, a reference axle speed decider 52 that decides the reference axle
speed, and a determiner 53 that determines, based on comparison between the axle speed
and the reference axle speed, whether any skid of any of the wheels 15a, 15b, 15c, and
15d occurs.
[0037] The axle speed decider 51 decides the axle speed that changes in accordance
20 with the rotational speeds of the wheels 15a, 15b, 15c, and 15d each attached to the ends
of the corresponding axle 14a, 14b, 14c, or 14d. In Embodiment 1, the circumferential
speed of each of the wheels 15a, 15b, 15c, and 15d is used as the axle speed.
[0038] More specifically, the axle speed decider 51 acquires the measurement value
of the rotational speed of each of the axles 14a, 14b, 14c, and 14d from the corresponding
25 speed detector 16a, 16b, 16c, or 16d. Each of the speed detectors 16a, 16b, 16c, and 16d
is located adjacent to the corresponding axle 14a, 14b, 14c, or 14d.
[0039] Each of the speed detectors 16a, 16b, 16c, and 16d includes a speed
13
generator that detects the rotational speed of the corresponding axle 14a, 14b, 14c, or 14d.
Each speed generator outputs a sensor signal with a frequency changing in proportion to
the rotational speed of the corresponding axle 14a, 14b, 14c, or 14d. Each of the speed
detectors 16a, 16b, 16c, and 16d decides the rotational speed of the corresponding axle
5 14a, 14b, 14c, or 14d based on a sensor signal output from the corresponding speed
generator, and outputs the decided rotational speed of the corresponding axle 14a, 14b,
14c, or 14d to the axle speed decider 51 in the slip-and-skid determining device 13.
[0040] The axle 14a and the wheel 15a attached to the axle 14a rotate integrally.
In this structure, the rotational speed of the axle 14a acquired from the speed detector 16a
10 presumably matches the rotational speed of the wheel 15a. Similarly, the axle 14b and
the wheel 15b attached to the axle 14b rotate integrally. In this structure, the rotational
speed of the axle 14b acquired from the speed detector 16b presumably matches the
rotational speed of the wheel 15b. Similarly, the axle 14c and the wheel 15c attached to
the axle 14c rotate integrally. In this structure, the rotational speed of the axle 14c
15 acquired from the speed detector 16c presumably matches the rotational speed of the
wheel 15c. Similarly, the axle 14d and the wheel 15d attached to the axle 14d rotate
integrally. In this structure, the rotational speed of the axle 14d acquired from the speed
detector 16d presumably matches the rotational speed of the wheel 15d.
[0041] The axle speed decider 51 calculates the circumferential speed of each of the
20 wheels 15a, 15b, 15c, and 15d based on the rotational speed of the corresponding axle
14a, 14b, 14c, or 14d acquired from the corresponding speed detector 16a, 16b, 16c, or
16d. Subsequently, the axle speed decider 51 outputs the circumferential speed of each
of the wheels 15a, 15b, 15c, and 15d to the reference axle speed decider 52 and the
determiner 53 as the axle speed of the corresponding axle 14a 14b, 14c, or 14d.
25 [0042] The reference axle speed decider 52 decides the reference axle speed based
on the axle speed and the physical quantity that changes during the travel of the railway
vehicle 1. The physical quantity changes during the travel of the railway vehicle 1, and
14
changes in a manner different from each axle speed of the vehicle 100 when the vehicle
100 slips or skids. As the physical quantity that changes during the travel of the railway
vehicle 1, the reference axle speed decider 52 uses, for example, the axle speed of the
other vehicle 200, in other words, the axle speed of each of the axles 24a, 24b, 24c, and
5 24d.
[0043] More specifically, the reference axle speed decider 52 selects a maximum
value of speeds that are the axle speed acquired from the axle speed decider 51 and the
reference axle speed acquired from a reference axle speed decider included in the slipand-skid determining device 23, and outputs the maximum value to the determiner 53
10 and to the slip-and-skid determining device 23 as the reference axle speed. Immediately
after the slip-and-skid determining device 13 starts a skid determining process, the
reference axle speed decider 52 outputs the maximum value of the axle speed of each of
the axles 14a, 14b, 14c, and 14d to the determiner 53 and to the slip-and-skid determining
device 23.
15 [0044] The determiner 53 determines, based on comparison between each axle
speed acquired from the axle speed decider 51 and the reference axle speed, whether any
skid of any wheel occurs. More specifically, the determiner 53 calculates a difference
between each axle speed acquired from the axle speed decider 51 and the reference axle
speed, and determines whether each difference is greater than or equal to a first threshold.
20 Each difference in speed indicates an absolute value of the difference between the
corresponding axle speed and the reference axle speed. The first threshold is defined in
accordance with a difference between the reference axle speed and each axle speed
generated when a skid occurs during, for example, test driving or simulation of the
railway vehicle 1. When any of the differences in speed is greater than or equal to the
25 first threshold, the corresponding axle speed is supposed to be sufficiently lower than the
reference axle speed. In this state, occurrence of a skid is determined. When each
difference in speed is less than the first threshold, no occurrence of skid of the wheels
15
15a, 15b, 15c, and 15d is determined.
[0045] The determiner 53 transmits the above determination result to the brake
control device 12. For example, the determiner 53 transmits, to the brake control device
12, information about the axle 14a, 14b, 14c, or 14d having the axle speed that has the
5 difference from the reference axle speed greater than or equal to the first threshold.
[0046] FIG. 4 illustrates a hardware configuration of control units in the brake
control devices 12 and 22 as well as the slip-and-skid determining devices 13 and 23 with
the above structures. The brake control devices 12 and 22 and the slip-and-skid
determining devices 13 and 23 each include a processor 91, a memory 92, and an
10 interface 93. The processor 91, the memory 92, and the interface 93 are connected to
one another with a bus 90. The function of each of the brake control devices 12 and 22
and the slip-and-skid determining devices 13 and 23 is implemented by software,
firmware, or a combination of software and firmware. The software and the firmware
are described as programs and are stored in the memory 92. The processor 91 reads and
15 executes the programs stored in the memory 92 to implement the functions of the above
components. In other words, the memory 92 stores programs for the processing
performed by the components of the corresponding brake control device 12 or 22 or the
corresponding slip-and-skid determining device 13 or 23.
[0047] The memory 92 is, for example, a nonvolatile or volatile semiconductor
20 memory such as a random-access memory (RAM), a read-only memory (ROM), a flash
memory, an erasable programmable ROM (EPROM), or an electrically erasable
programmable ROM (EEPROM), or a magnetic disk, a flexible disk, an optical disc, a
compact disc, a minidisc, or a digital versatile disc (DVD).
[0048] The brake control device 12 is connected to the master controller 5, the load
25 detector 11, the slip-and-skid determining device 13, and the anti-skid valves 19a, 19b,
19c, and 19d via the interface 93. The brake control device 22 is connected to the
master controller 5, the load detector 21, the slip-and-skid determining device 23, and the
16
anti-skid valves 29a, 29b, 29c, and 29d via the interface 93. The slip-and-skid
determining device 13 is connected to the master controller 5, the slip-and-skid
determining device 23, and the speed detectors 16a, 16b, 16c, and 16d via the interface
93. The slip-and-skid determining device 23 is connected to the master controller 5, the
5 slip-and-skid determining device 13, and the speed detectors 26a, 26b, 26c, and 26d via
the interface 93. The interface 93 includes an interface module complying with one or
more standards as appropriate for connection targets.
[0049] The slip-and-skid determining devices 13 and 23 with the above structure
perform the skid determining process in the same manner. Thus, the skid determining
10 process performed by the slip-and-skid determining device 13 is described with reference
to FIG. 5. Upon receiving an operation command from the master controller 5, the slipand-skid determining device 13 starts the process in FIG. 5. When the received
operation command does not include a braking command (No in step S11), the
processing in step S11 is repeated.
15 [0050] When the operation command includes a braking command (Yes in step
S11), the axle speed decider 51 decides the axle speed of each of the axles 14a, 14b, 14c,
and 14d based on the measurement value from the corresponding speed detector 16a,
16b, 16c, or 16d (step S12). The reference axle speed decider 52 decides, as the
reference axle speed, the maximum value of speeds that are the axle speed of each axle
20 decided in step S12 and the reference axle speed acquired from the slip-and-skid
determining device 23 (step S13).
[0051] The determiner 53 calculates the difference between each axle speed
decided in step S12 and the reference axle speed decided in step S13 (step S14). When
the differences in speed calculated in step S14 are less than the first threshold (No in step
25 S15), the processing in step S11 and subsequent steps described above is repeated.
[0052] When at least any of the differences in speed calculated in step S14 is
greater than or equal to the first threshold (Yes in step S15), the determiner 53 outputs, to
17
the brake control device 12, information about the axle 14a, 14b, 14c, or 14d having an
axle speed that has a difference from the reference axle speed greater than or equal to the
first threshold, in other words, information about any one of the axles 14a, 14b, 14c, and
14d to which the skid wheel 15a, 15b, 15c, or 15d is attached (step S16). When the
5 processing in step S16 ends, the processing in step S11 and subsequent steps described
above is repeated.
[0053] FIG. 6 illustrates changes in the reference axle speed and each axle speed in
a comparative example. In the comparative example, the reference axle speed is
determined based simply on each axle speed in a single vehicle, and the occurrence of
10 skid of each wheel is determined based on whether the difference between the
corresponding axle speed and the reference axle speed is greater than or equal to the
threshold. In FIG. 6, the solid line indicates changes in the axle speed, and the dotted
line indicates changes in the reference axle speed. In FIG. 6, the horizontal axis
indicates time, and the vertical axis indicates speed. The brake control is started at time
15 T1. At time T1 and subsequent times, each axle speed and the reference axle speed
decrease at a constant rate based on the target deceleration.
[0054] All the wheels in the single vehicle skid at time T2. At time T2, each axle
speed starts decreasing rapidly. In the comparative example, as described above, the
reference axle speed is simply based on each axle speed in the single vehicle. Thus,
20 when all the wheels skid, the reference axle speed rapidly decreases in the same manner
as each axle speed. In this state, the difference between the reference axle speed and
each axle speed does not increase. In the comparative example, no occurrence of skid is
determined by mistake although all the wheels skid.
[0055] When, for example, all the wheels 15a, 15b, 15c, and 15d skid and none of
25 the wheels 25a, 25b, 25c, and 25d skids, each axle speed in the vehicle 100 and the
reference axle speed change as illustrated in FIG. 7. In FIG. 7, the solid line indicates
changes in the axle speed, and the dotted line indicates changes in the reference axle
18
speed. In FIG. 7, the horizontal axis indicates time, and the vertical axis indicates speed.
The brake control is started at time T1. At time T1, the master controller 5 is controlled
to transmit an operation command including a braking command to the slip-and-skid
determining devices 13 and 23. At time T1 and subsequent times, each axle speed and
5 the reference axle speed decrease at a constant rate based on the target deceleration.
[0056] All the wheels 15a, 15b, 15c, and 15d skid at time T2. At time T2, the axle
speed of each of the axles 14a, 14b, 14c, and 14d starts decreasing rapidly. None of the
wheels 25a, 25b, 25c, and 25d skids at time T2 and subsequent times. Thus, the
reference axle speed acquired by the slip-and-skid determining device 13 from the slip10 and-skid determining device 23 decreases at a constant rate based on the target
deceleration. Thus, although the axle speed of each of the axles 14a, 14b, 14c, and 14d
decreases rapidly, the reference axle speed decider 52 in the slip-and-skid determining
device 13 outputs the reference axle speed that decreases at a constant rate, unlike the
rapidly decreasing axle speed of each of the axles 14a, 14b, 14c, and 14d.
15 [0057] At time T3, for example, the difference between the axle speed of each of
the axles 14a, 14b, 14c, and 14d and the reference axle speed reaches the first threshold.
At time T3, the difference between the axle speed of each of the axles 14a, 14b, 14c, and
14d and the reference axle speed is greater than or equal to the first threshold, causing the
determiner 53 in the slip-and-skid determining device 13 to transmit, to the brake control
20 device 12, the determination result indicating all the wheels 15a, 15b, 15c, and 15d
attached to the axles 14a, 14b, 14c, and 14d skid.
[0058] Upon receiving the above determination result from the slip-and-skid
determining device 13, the brake control device 12 opens the anti-skid valves 19a, 19b,
19c, and 19d to discharge the fluid in the brake cylinders 18a, 18b, 18c, and 18d. This
25 reduces the pressure of the fluid in the brake cylinders 18a, 18b, 18c, and 18d, and thus
reduces the pressing force for pressing the brake blocks 17a, 17b, 17c, and 17d against
the wheels 15a, 15b, 15c, and 15d. When the pressing force is reduced, or in other
19
words, when the brake is released, the difference between the axle speed of each of the
axles 14a, 14b, 14c, and 14d and the reference axle speed starts decreasing.
Subsequently, the difference between the axle speed of each of the axles 14a, 14b, 14c,
and 14d and the reference axle speed reaches zero, achieving re-adhesion of the wheels
5 15a, 15b, 15c, and 15d to the rails at time T4.
[0059] As described above, the slip-and-skid determining device 13 according to
Embodiment 1 decides the reference axle speed based on the axle speed of each of the
axles 14a, 14b, 14c, and 14d in the vehicle 100 and the reference axle speed based on the
axle speed of each of the axles 24a, 24b, 24c, and 24d in the other vehicle 200. This
10 prevents the reference axle speed from decreasing rapidly unlike the axle speed of each of
the axles 14a, 14b, 14c, and 14 in the vehicle 100, although all the wheels 15a, 15b, 15c,
and 15d attached to the axles 14a, 14b, 14c, and 14d skid, thus allowing determining,
based on the difference between each axle speed and the reference axle speed, whether
any skid of any wheel occurs. Similarly, the slip-and-skid determining device 23 can
15 determine whether any skid of any of the wheels 25a, 25b, 25c, and 25d attached to the
axles 24a, 24b, 24c, and 24d of the vehicle 200 occurs also when all the wheels 25a, 25b,
25c, and 25d skid.
[0060] Embodiment 2
The method for deciding the reference axle speed based on each axle speed and the
20 physical quantity that changes during the travel of the railway vehicle is not limited to the
examples described above. A slip-and-skid determining device according to
Embodiment 2 decides the reference axle speed with a method different from the method
used in Embodiment 1, and is thus described focusing on differences from Embodiment
1.
25 [0061] In FIG. 8, a railway vehicle 2 includes the vehicle 100. The vehicle 100
includes a slip-and-skid determining device 31 that determines whether any skid of any
of the wheels 15a, 15b, 15c, and 15d in the vehicle 100 occurs and an acceleration
20
detector 82 that detects the acceleration of the vehicle 100.
[0062] The acceleration detector 82 measures the acceleration of the vehicle 100,
and transmits data indicating the measurement value to the slip-and-skid determining
device 31. When the vehicle 100 accelerates, the measurement value is positive.
5 When the vehicle 100 decelerates, the measurement value is negative.
[0063] The slip-and-skid determining device 31 in FIG. 9 includes a vehicle speed
decider 54 that decides the speed of the vehicle 100 based on the measurement value of
the acceleration of the vehicle 100 acquired from the acceleration detector 82, and a
reference axle speed decider 55 that decides the reference axle speed based on the speed
10 of the railway vehicle 2 and the axle speed of each of the axles 14a, 14b, 14c, and 14d
determined by the axle speed decider 51. The slip-and-skid determining device 31 with
the above structure has the same hardware configuration as in Embodiment 1.
[0064] Upon receiving an operation command from the master controller 5, the
vehicle speed decider 54 repeatedly integrates the measurement value of the acceleration
15 of the vehicle 100 acquired from the acceleration detector 82, and outputs the integral of
the measured acceleration to the reference axle speed decider 55 as the speed of the
vehicle 100. The speed of the vehicle 100 presumably matches the speed of the railway
vehicle 2 including the vehicle 100.
[0065] The reference axle speed decider 55 decides the reference axle speed based
20 on the axle speed of each of the axles 14a, 14b, 14c, and 14d decided by the axle speed
decider 51 and the speed of the vehicle 100 decided by the vehicle speed decider 54.
More specifically, the reference axle speed decider 55 selects a maximum value of speeds
that are the axle speed of each of the axles 14a, 14b, 14c, and 14d decided by the axle
speed decider 51 and the speed of the vehicle 100 decided by the vehicle speed decider
25 54, and outputs, as the reference axle speed, the maximum value to the determiner 53.
[0066] The skid determining process performed by the slip-and-skid determining
device 31 with the above structure is described with reference to FIG. 10. Upon
21
receiving an operation command from the master controller 5, the slip-and-skid
determining device 31 starts the process in FIG. 10. The vehicle speed decider 54
decides the speed of the vehicle 100 based on the measurement value of the acceleration
of the vehicle 100 acquired from the acceleration detector 82 (step S21). The processing
5 in steps S11 and S12 is the same as the processing in steps S11 and S12 performed by the
slip-and-skid determining devices 13 and 23 in FIG. 5. When the received operation
command does not include a braking command (No in step S11), the processing in step
S21 and subsequent steps described above is repeated as illustrated in FIG. 10.
[0067] After step S12, the reference axle speed decider 55 decides, as the reference
10 axle speed, the maximum value of speeds that are the axle speed of each axle decided in
step S12 and the speed of the vehicle 100 decided in step S21 (step S22). The
processing in subsequent steps S14 to S16 is the same as the processing in steps S14 to
S16 performed by the slip-and-skid determining devices 13 and 23 in FIG. 5.
[0068] When all the wheels 15a, 15b, 15c, and 15d skid, the speed of the vehicle
15 100 does not decrease rapidly unlike the axle speed of each of the axles 14a, 14b, 14c,
and 14d. When the railway vehicle 2 travels in a flat section and when all the wheels
15a, 15b, 15c, and 15d skid, for example, the speed of the railway vehicle 2 gradually
decreases, causing the reference axle speed output from the reference axle speed decider
55 to decrease gradually. In this state, based on comparison between the axle speed of
20 each of the axles 14a, 14b, 14c, and 14d and the reference axle speed, the occurrence of
skid of the wheels 15a, 15b, 15c, and 15d can be determined.
[0069] As described above, the slip-and-skid determining device 31 according to
Embodiment 2 decides the reference axle speed based on the axle speed of each of the
axles 14a, 14b, 14c, and 14d in the vehicle 100 and the speed of the vehicle 100. This
25 prevents the reference axle speed from decreasing rapidly unlike the axle speed of each of
the axles 14a, 14b, 14c, and 14d, although all the wheels 15a, 15b, 15c, and 15d attached
to the axles 14a, 14b, 14c, and 14d in the vehicle 100 skid. This allows determination of
22
the occurrence of a skid of any wheel based on the difference between each axle speed
and the reference axle speed.
[0070] Embodiment 3
The method for deciding the reference axle speed based on each axle speed and the
5 physical quantity that changes during the travel of the railway vehicle is not limited to the
examples described above. A slip-and-skid determining device according to
Embodiment 3 determines the reference axle speed with a method different from the
methods in Embodiments 1 and 2, and is thus described focusing on differences from the
methods in Embodiments 1 and 2.
10 [0071] In FIG. 11, a slip-and-skid determining device 32 according to Embodiment
3 is mounted on the vehicle 100, similarly to the slip-and-skid determining device 31
according to Embodiment 2. The slip-and-skid determining device 32 includes a
reference axle speed decider 56 that decides the reference axle speed based on the axle
speed of each of the axles 14a, 14b, 14c, and 14d decided by the axle speed decider 51,
15 and the acceleration of the railway vehicle 1. The slip-and-skid determining device 32
with the above structure has the same hardware configuration as in Embodiment 1.
[0072] The reference axle speed decider 56 decides the reference axle speed that
maintains the rate of change in the reference axle speed within a target range. More
specifically, the reference axle speed decider 56 decides the reference axle speed that
20 maintains the rate of change in the reference axle speed within the target range defined
based on the acceleration of the railway vehicle 1. The acceleration of the vehicle 100
can be used as the acceleration of the railway vehicle 2. Thus, the reference axle speed
decider 56 decides the reference axle speed to maintain the rate of change in the reference
axle speed within the target range defined based on the measurement value of the
25 acceleration of the vehicle 100 acquired from the acceleration detector 82.
[0073] As illustrated in FIG. 12, the reference axle speed decider 56 includes a
maximum value outputter 70 that outputs the maximum value of the axle speed and an
23
acceleration converter 71 that converts the acceleration of the vehicle 100 acquired from
the acceleration detector 82 to a change in the speed of the vehicle 100 in a calculation
cycle. The calculation cycle corresponds to an interval at which the reference axle
speed decider 56 repeats deciding the reference axle speed, and is thus determined based
5 on a period of time taken for deciding the reference axle speed. The calculation cycle is,
for example, one second.
[0074] The reference axle speed decider 56 includes an adder 72 that adds a value
output from the acceleration converter 71 to the most recently decided reference axle
speed, and a maximum value outputter 73 that outputs a maximum value of values output
10 from the maximum value outputter 70 and from the adder 72.
[0075] The maximum value outputter 70 outputs, to the maximum value outputter
73, the maximum value of the axle speed of each of the axles 14a, 14b, 14c, and 14d
acquired from the axle speed decider 51.
[0076] When the measurement value of the acceleration of the vehicle 100 acquired
15 from the acceleration detector 82 indicates a change in the speed of the railway vehicle 1
per second (in km/h/s) and the calculation cycle for the reference axle speed decider 56 is
one second, the acceleration converter 71 outputs the measurement value of the
acceleration of the vehicle 100 acquired from the acceleration detector 82 to the adder 72
as the change in the speed (in km/h) of the vehicle 100 in the calculation cycle.
20 [0077] The adder 72 adds the value (in km/h) output from the acceleration
converter 71 to the reference axle speed (in km/h) most recently output from the
maximum value outputter 73. The value output from the adder 72 corresponds to the
axle speed of each of the axles 14a, 14b, 14c, and 14d that can be achieved when no skid
occurs.
25 [0078] The maximum value outputter 73 outputs the maximum value of values
output from the maximum value outputter 70 and from the adder 72. When all the
wheels 15a, 15b, 15c, and 15d attached to the axles 14a, 14b, 14c, and 14d skid, the axle
24
speed of each of the axles 14a, 14b, 14c, and 14d decreases rapidly. This causes the
value output from the maximum value outputter 70 to decrease rapidly and fall below the
value output from the adder 72. The maximum value outputter 73 then outputs, as the
reference axle speed, the value output from the adder 72 to the determiner 53.
5 [0079] Although all the wheels 15a, 15b, 15c, and 15d skid, the reference axle
speed decider 56 outputs the reference axle speed corresponding to the axle speed of each
of the axles 14a, 14b, 14c, and 14d that can be achieved when no skid occurs. This
allows the determiner 53 to determine, based on the difference between the axle speed of
each of the axles 14a, 14b, 14c, and 14d and the reference axle speed, whether any skid of
10 any wheel occurs.
[0080] As described above, the slip-and-skid determining device 32 according to
Embodiment 3 changes the reference axle speed that maintains the rate of change in the
reference axle speed within the target range, or more specifically, within the target range
defined in accordance with the acceleration of the vehicle 100. This prevents the
15 reference axle speed from decreasing rapidly unlike the axle speed of each of the axles
14a, 14b, 14c, and 14 in the vehicle 100, although all the wheels 15a, 15b, 15c, and 15d
attached to the axles 14a, 14b, 14c, and 14d skid, thus allowing determination of the
occurrence of a skid of any wheel based on the difference between each axle speed and
the reference axle speed.
20 [0081] Embodiment 4
To determine whether any slip or a skid in the vehicle, the determination may be
performed based on the acceleration of the railway vehicle, in addition to comparison
between each axle speed and the reference axle speed. A slip-and-skid determining
device according to Embodiment 4 determines whether any skid occurs with a method
25 different from the methods in Embodiments 1 to 3, and is thus described focusing on
differences from the methods in Embodiments 1 to 3.
[0082] In FIG. 13, the vehicle 100 includes a slip-and-skid determining device 33,
25
and the vehicle 200 includes a slip-and-skid determining device 34. The vehicle 100
includes the acceleration detector 82. The acceleration detector 82 transmits data
indicating the measurement value of the acceleration of the vehicle 100 to the slip-andskid determining devices 33 and 34. The acceleration of the vehicle 100 can correspond
5 to the acceleration of the railway vehicle 1 including the vehicles 100 and 200.
[0083] The slip-and-skid determining devices 33 and 34 have the same structure.
The structure of the slip-and-skid determining device 33 is thus described below. In
FIG. 14, the slip-and-skid determining device 33 includes an axle acceleration decider 57
that decides each axle acceleration as the circumferential acceleration of the
10 corresponding wheel 15a, 15b, 15c, or 15d, an acceleration difference calculator 58 that
decides a difference between each axle acceleration and the acceleration of the railway
vehicle 1, and a determiner 59 that determines whether any skid of any of the wheels 15a,
15b, 15c, and 15d occurs based on comparison between each axle speed and the reference
axle speed or comparison between each axle acceleration and the acceleration of the
15 railway vehicle 1. The slip-and-skid determining devices 33 and 34 with the above
structure have the same hardware configuration as in Embodiment 1.
[0084] The axle acceleration decider 57 acquires the axle speed of each of the axles
14a, 14b, 14c, and 14d from the axle speed decider 51, and decides the axle acceleration
(in km/h/s) for each of the axles 14a, 14b, 14c, and 14d based on a change in the
20 corresponding axle speed per unit time. The axle acceleration decider 57 outputs each
axle acceleration to the acceleration difference calculator 58.
[0085] The acceleration difference calculator 58 calculates the difference between
the measurement value of the acceleration of the vehicle 100 acquired from the
acceleration detector 82 and the axle acceleration of each of the axles 14a, 14b, 14c, and
25 14d, and outputs the calculated difference in acceleration to the determiner 59. Each
difference in acceleration indicates an absolute value of the difference between the
measurement value of the acceleration of the vehicle 100 and each axle acceleration.
26
[0086] The determiner 59 determines whether any skid occurs, based on the
difference between each axle speed and the reference axle speed or based on each
difference in acceleration. The determination based on the difference between each axle
speed and the reference axle speed is performed as in Embodiment 1. More
5 specifically, as in Embodiment 1, the determiner 59 determines whether the difference
between each axle speed and the reference axle speed is greater than or equal to the first
threshold. When any of the differences in speed is greater than or equal to the first
threshold, the corresponding axle speed is sufficiently lower than the reference axle
speed. In this state, occurrence of a skid can be determined.
10 [0087] The determination of a skid based on each difference in acceleration is
described. The determiner 59 determines whether each difference in acceleration
acquired from the acceleration difference calculator 58 is greater than or equal to a
second threshold. The second threshold is defined based on a difference between the
acceleration of the railway vehicle 1 and each axle speed generated when a skid occurs
15 during, for example, the test driving or simulation of the railway vehicle 1. When any
of the differences in acceleration is greater than or equal to the second threshold, the
corresponding axle acceleration is sufficiently lower than the acceleration of the vehicle
100. In this state, a skid can be detected.
[0088] The slip-and-skid determining devices 33 and 34 with the above structure
20 perform the skid determining process in the same manner. Thus, the skid determining
process performed by the slip-and-skid determining device 33 is described with reference
to FIG. 15. Upon receiving an operation command from the master controller 5, the
slip-and-skid determining device 33 starts the process in FIG. 15. The processing in
steps S11 and S12 is the same as the processing in steps S11 and S12 performed by the
25 slip-and-skid determining device 13 according to Embodiment 1 in FIG. 5.
[0089] The axle acceleration decider 57 decides each axle acceleration based on the
corresponding axle speed decided in step S12 (step S31). The acceleration difference
27
calculator 58 calculates the difference in acceleration based on each axle acceleration
decided in step S31 and the measurement value of the acceleration of the vehicle 100
acquired from the acceleration detector 82 (step S32). The determiner 59 determines
whether the difference in acceleration calculated in step S32 is greater than or equal to the
5 second threshold.
[0090] When at least any of the differences in acceleration calculated in step S32 is
greater than or equal to the second threshold (Yes in step S33), the determiner 59 outputs,
to the brake control device 12, information about the axle 14a, 14b, 14c, or 14d having an
axle acceleration that has a difference from the acceleration of the vehicle 100 greater
10 than or equal to the second threshold, in other words, information about any one of the
axles 14a, 14b, 14c, and 14d to which the skid wheel 15a, 15b, 15c, or 15d is attached
(step S34). When the processing in step S34 ends, the processing in step S11 and
subsequent steps described above is repeated.
[0091] When all the differences in acceleration calculated in step S32 are less than
15 the second threshold (No in step S33), the processing in step S11 and subsequent steps
described above is repeated without the processing in step S34 being performed.
[0092] While the processing in steps S31 to S34 is being performed, the processing
in steps S13 to S16 is performed in parallel. The processing in steps S13 to S16 is the
same as the processing in steps S13 to S16 performed by the slip-and-skid determining
20 device 13 according to Embodiment 1 in FIG. 5.
[0093] As described above, the slip-and-skid determining device 33 according to
Embodiment 4 determines whether any skid occurs based on comparison between the
axle acceleration of each of the axles 14a, 14b, 14c, and 14d in the vehicle 100 and the
acceleration of the vehicle 100, in addition to being based on comparison between the
25 axle speed of each of the axles 14a, 14b, 14c, and 14d and the reference axle speed
decided based on the axle speed of each of the axles 24a, 24b, 24c, and 24d in the vehicle
200.
28
[0094] The slip-and-skid determining device 33 determines that a skid occurs when
any of the differences in acceleration is greater than or equal to the second threshold or
when any of the differences in speed is greater than or equal to the first threshold. This
allows determination of the occurrence of a skid more accurately and more quickly than
5 in Embodiments 1 to 3.
[0095] Embodiment 5
The slip-and-skid determining devices described above can determine the
occurrence of a slip in addition to a skid. A slip-and-skid determining device according
to Embodiment 5 determines the occurrence of a skid and a slip, and is described
10 focusing on differences from Embodiment 1.
[0096] The vehicle 100 includes a power converter 83 illustrated in FIG. 16 as a
drive device for the railway vehicle 1, an electric motor 87 that operates on power
supplied from the power converter 83 to generate a driving force for the railway vehicle
1, and a slip-and-skid determining device 35 that determines the occurrence of a slip or a
15 skid.
[0097] The power converter 83 is, for example, a direct current (DC)-three-phase
converter mounted on the railway vehicle 1 using a DC feeder, and converts DC power
supplied from a power supply, which is not illustrated, to three-phase alternating current
(AC) power to supply the three-phase AC power to a load. The power converter 83
20 includes an input terminal 83a to be connected to the power supply and an input terminal
83b to be grounded. The power converter 83 further includes a power conversion
circuit 84 that converts DC power supplied from the power supply to three-phase AC
power and supplies the three-phase AC power to the electric motor 87, a current detection
circuit 85 that measures the phase current output from the power conversion circuit 84,
25 and a power conversion circuit controller 86 that controls the power conversion circuit
84. The power converter 83 still further includes a reactor L1 and a capacitor C1. The
reactor L1 and the capacitor C1 are connected in series between the input terminals 83a
29
and 83b. The power converter 83 with the above structure is located under the floor of
the vehicle 100 as a motor coach.
[0098] The input terminal 83a is electrically connected to the power supply, or
more specifically, to a current collector through a contactor or a circuit breaker, which are
5 not illustrated. The current collector acquires power supplied from a substation through
a power supply line. Examples of the current collector include a pantograph for
acquiring the power through an overhead line as an example of a power supply line and a
current collecting shoe for acquiring the power through a third rail as an example of a
power supply line. The input terminal 83b is grounded with, for example, a ground
10 ring, a ground brush, or the wheels, which are not illustrated.
[0099] The power conversion circuit 84 is, for example, an inverter that varies the
effective voltage and the frequency of the output AC power. The power conversion
circuit 84 includes multiple switching elements. Each switching element switches under
control of the power conversion circuit controller 86. Each switching element is, for
15 example, an insulated-gate bipolar transistor (IGBT).
[0100] The current detection circuit 85 includes a current transformer (CT) attached
to a busbar that electrically connects the power conversion circuit 84 and the electric
motor 87. The current detection circuit 85 measures the phase current, or more
specifically, a U-phase current, a V-phase current, and a W-phase current output from the
20 power conversion circuit 84. The current detection circuit 85 transmits the
measurement value of each phase current to the power conversion circuit controller 86.
[0101] The power conversion circuit controller 86 acquires an operation command
from the master controller 5. The power conversion circuit controller 86 generates a
power conversion control signal for controlling each switching element in the power
25 conversion circuit 84 in accordance with the operation command and the determination
result from the slip-and-skid determining device 35, and outputs the power conversion
control signal to the power converter circuit 84. The power conversion control signal is,
30
for example, a pulse width modulation (PWM) signal.
[0102] The reactor L1 has one end connected to the input terminal 83a. The
reactor L1 has the other end connected to a primary terminal of the power conversion
circuit 84. The capacitor C1 has one end connected to the connecting point between the
5 other end of the reactor L1 and the primary terminal of the power conversion circuit 84.
The capacitor C1 has the other end connected to the connecting point between the input
terminal 83b and the primary terminal of the power conversion circuit 84. The reactor
L1 and the capacitor C1 are included in an LC filter for attenuating harmonic components
resulting from the switching operation performed by the power conversion circuit 84.
10 [0103] The electric motor 87 is mounted on the bogie supporting the vehicle body
of the vehicle 100. When the electric motor 87 operates on power supplied from the
power converter 83, the shaft of the electric motor 87 rotates. The rotational force of the
shaft is transmitted to the axles 14a, 14b, 14c, and 14d through a joint and a gear device.
More specifically, the vehicle 100 includes two bogies for supporting the vehicle body.
15 Each bogie includes two electric motors 87. The rotational force of the shafts in the
electric motors 87 on one bogie is transmitted to the axles 14a and 14b, and the rotational
force of the shafts in the electric motors 87 on the other bogie is transmitted to the axles
14c and 14d. In response to the rotation of the axles 14a, 14b, 14c, and 14d, the wheels
15a, 15b, 15c, and 15d each attached to both ends of the corresponding axle 14a, 14b,
20 14c, or 14d rotate as well. This generates the driving force of the railway vehicle 1.
[0104] The slip-and-skid determining device 35 in FIG. 17 acquires the reference
axle speed from a slip-and-skid determining device 36 in the vehicle 200. The slip-andskid determining devices 35 and 36 have the same structure. Thus, the slip-and-skid
determining device 35 that determines whether any slip or skid of any wheel occurs is
25 described. The slip-and-skid determining device 35 includes a reference axle speed
decider 60 and a determiner 61. The reference axle speed decider 60 decides, in
response to an operation command, the reference axle speed based on each axle speed
31
decided by the axle speed decider 51 and the reference axle speed acquired from the slipand-skid determining device 36. The determiner 61 determines whether any slip or skid
occurs based on comparison between each axle speed and the reference axle speed. The
slip-and-skid determining devices 35 and 36 with the above structure have the same
5 hardware configuration as in Embodiment 1.
[0105] The reference axle speed decider 60 in FIG. 18 includes the maximum value
outputter 70 that outputs a maximum value of the axle speed, a minimum value outputter
74 that outputs a minimum value of the axle speed, and a switch 75 that outputs the value
output from the maximum value outputter 70 or the value output from the minimum
10 value outputter 74 in response to an operation command.
[0106] The maximum value outputter 70 acquires the axle speed of each of the
axles 14a, 14b, 14c, and 14d from the axle speed decider 51, and outputs the maximum
value in the acquired axle speed to the switch 75.
[0107] The minimum value outputter 74 acquires the axle speed of each of the
15 axles 14a, 14b, 14c, and 14d from the axle speed decider 51, and outputs the minimum
value in the acquired axle speed to the switch 75.
[0108] When the operation command acquired from the master controller 5
includes a braking command, the switch 75 outputs, as the reference axle speed, the value
output from the maximum value outputter 70 to the determiner 61 and to the slip-and20 skid determining device 36. When the operation command does not include a braking
command, or in other words, when the operation command includes a powering
command or a coasting command, the switch 75 outputs, as the reference axle speed, the
value output from the minimum value outputter 74 to the determiner 61 and to the slipand-skid determining device 36.
25 [0109] When the operation command includes a braking command, the determiner
61 calculates a difference between each axle speed acquired from the axle speed decider
51 and the reference axle speed acquired from the reference axle speed decider 60, and
32
determines whether each difference in speed is greater than or equal to the first threshold.
Each difference in speed indicates an absolute value of the difference between the
corresponding axle speed and the reference axle speed. When any of the differences in
speed is greater than or equal to the first threshold, the corresponding axle speed is
5 sufficiently lower than the reference axle speed. In this state, occurrence of a skid can
be determined. When each difference in speed is less than the first threshold, no
occurrence of skid of the wheels 15a, 15b, 15c, and 15d is determined. The determiner
61 transmits the above determination result to the brake control device 12.
[0110] When the operation command does not include a braking command, the
10 determiner 61 calculates the difference between each axle speed acquired from the axle
speed decider 51 and the reference axle speed acquired from the reference axle speed
decider 60, and determines whether each difference in speed is greater than or equal to a
third threshold. Each difference in speed indicates an absolute value of the difference
between the corresponding axle speed and the reference axle speed. The third threshold
15 is defined based on a difference between the reference axle speed and each axle speed
generated when a slip occurs in, for example, the test driving or simulation of the railway
vehicle 1. When any of the differences in speed is greater than or equal to the third
threshold, the corresponding axle speed is sufficiently higher than the reference axle
speed. In this state, occurrence of a slip can be determined. When each difference in
20 speed is less than the third threshold, no occurrence of slip of the wheels 15a, 15b, 15c,
and 15d is determined.
[0111] The determiner 61 transmits the above determination result to the power
conversion circuit controller 86. When any of the differences in speed is greater than or
equal to the third threshold, for example, the determiner 61 transmits a notice of a slip to
25 the power conversion circuit controller 86.
[0112] A power conversion process performed by the power converter 83 with the
above structure in FIG. 16 is described below. When the operation command includes a
33
powering command, the power converter 83 converts the DC power supplied from the
power supply to the three-phase AC power, and supplies the three-phase AC power to the
electric motor 87. The electric motor 87 operates on the supplied three-phase AC power
to generate the driving force of the railway vehicle 1.
5 [0113] More specifically, when the operation command includes a powering
command, the power conversion circuit controller 86 decides a torque command value τ*
as a target torque for the electric motor 87 in accordance with the target acceleration
indicated by the powering command as a target value for the acceleration of the railway
vehicle 1 and the measurement value of the rotational speed of the electric motor 87
10 acquired from a speed detector, which is not illustrated. The power conversion circuit
controller 86 decides an exciting current command value id* and a torque current
command value iq* in accordance with the torque command value τ*. To decide an
exciting current value id and a torque current value iq, the power conversion circuit
controller 86 converts, for the measurement value of the phase current acquired from the
15 current detection circuit 85, three-phase coordinates to dq rotational coordinates based on
an estimated position θ estimated from the measurement value of the rotational speed of
the electric motor 87.
[0114] The power conversion circuit controller 86 decides an exciting voltage
command value Vd* based on a difference between the exciting current value id and the
20 exciting current command value id*, and decides a torque voltage command value Vq*
based on a difference between the torque current value iq and the torque current
command value iq*. To decide a U-phrase voltage command value Vu*, a V-phase
voltage command value Vv*, and a W-phase voltage command value Vw*, the power
conversion circuit controller 86 converts, for the exciting voltage command value Vd*
25 and the torque voltage command value Vq*, the dq rotational coordinates to the threephase coordinates based on the estimated position θ. The power conversion circuit
controller 86 then generates and outputs the power conversion control signal for
34
controlling the switching of each switching element in the power conversion circuit 84
based on each of the U-phase voltage command value Vu*, the V-phase voltage
command value Vv*, and the W-phase voltage command value Vw* and the
corresponding carrier wave.
5 [0115] Upon receiving the notice of a slip from the slip-and-skid determining
device 35, the power conversion circuit controller 86 sets the torque command value τ* to
a smaller value than the above torque command value τ* decided in accordance with the
target acceleration of the railway vehicle 1 indicated by the powering command and the
measurement value of the rotational speed of the electric motor 87 as described above.
10 The power conversion circuit controller 86 performs the above process based on the
torque command value τ* set to the smaller value, and generates the power conversion
control signal.
[0116] When the power conversion control signal is provided to a gate signal for
each switching element in the power conversion circuit 84, the corresponding switching
15 element performs a switching operation. This allows the power conversion circuit 84 to
convert the DC power to the three-phase AC power and supply the three-phase AC
power to the electric motor 87.
[0117] When the operation command includes a braking command, the electric
motor 87 operating as a power generator supplies the three-phase AC power to the power
20 converter 83. The power converter 83 converts the three-phase AC power supplied
from the electric motor 87 to the DC power, and supplies the DC power through the
current collector and the power supply line to other railway vehicles traveling near the
railway vehicle 1 including the power converter 83. The three-phase AC power
generated by the electric motor 87 is supplied to and consumed in the other railway
25 vehicles. This generates a regenerative brake force for decelerating the railway vehicle
1.
[0118] More specifically, when the operation command includes a braking
35
command, the power conversion circuit controller 86 acquires the measurement value of
the voltage between terminals of the capacitor C1 from a voltage sensor, which is not
illustrated, and acquires, from the current detection circuit 85, the measurement value of
each phase current flowing from the electric motor 87 to the power converter circuit 84.
5 Based on the measurement value of the voltage between terminals in the capacitor C1
and the measured phase current flowing from the electric motor 87 to the power converter
circuit 84, the power conversion circuit controller 86 determines a voltage command
value as a target value for the voltage output from the power converter circuit 84.
[0119] The target value for the voltage output from the power conversion circuit 84
10 is included within a target range of, for example, voltages greater than the overhead
voltage and voltages with which the regenerative brake can be provided. The power
conversion circuit controller 86 then generates, in accordance with the voltage command
value, the power conversion control signal for controlling the switching of each switching
element in the power conversion circuit 84, and outputs the power conversion control
15 signal.
[0120] When the power conversion control signal is provided to a gate signal for
each switching element in the power conversion circuit 84, the corresponding switching
element performs a switching operation. This allows the power conversion circuit 84 to
convert the three-phase AC power supplied from the electric motor 87 to the DC power
20 and charge the capacitor C1 with the DC power.
[0121] As described above, when the other railway vehicles are accelerating near
the railway vehicle 1 including the power converter 83, the power generated by the
electric motor 87 is supplied to and consumed in the other railway vehicles. This
generates a regenerative brake force for decelerating the railway vehicle 1.
25 [0122] The slip-and-skid determining devices 35 and 36 perform a slip and skid
determination process in the same manner. Thus, the skid determination process
performed by the slip-and-skid determining device 35 is described with reference to FIG.
36
19. Upon receiving an operation command from the master controller 5, the slip-andskid determining device 35 starts the process in FIG. 19.
[0123] The processing in step S12 is the same as the processing in step S12
performed by the slip-and-skid determining device 13 according to Embodiment 1 in
5 FIG. 5. When the received operation command includes a braking command (Yes in
step S41), the processing in steps S13 to S16 is performed. The processing in steps S13
to S16 is the same as the processing in steps S13 to S16 performed by the slip-and-skid
determining device 13 according to Embodiment 1 in FIG. 5. When the differences in
speed calculated in step S14 are less than the first threshold (No in step S15), the
10 processing in step S12 and subsequent steps described above is repeated. When any of
the differences in speed calculated in step S14 is greater than or equal to the first
threshold (Yes in step S15), the determiner 61 outputs, to the brake control device 12,
information about the axle 14a, 14b, 14c, or 14d having an axle speed that has a
difference from the reference axle speed greater than or equal to the first threshold (step
15 S16). When the processing in step S16 ends, the processing in step S12 and subsequent
steps described above is repeated.
[0124] When the received operation command does not include a braking
command (No in step S41), the reference axle speed decider 60 decides, as the reference
axle speed, the minimum value of speeds that are each axle speed decided in step S12 and
20 the reference axle speed acquired from the slip-and-skid determining device 36 (step
S42).
[0125] The determiner 61 calculates the difference between each axle speed
decided in step S12 and the reference axle speed decided in step S42 (step S43). When
the differences in speed calculated in step S43 are less than the third threshold (No in step
25 S44), the processing in step S12 and subsequent steps described above is repeated.
[0126] When at least any of the differences in speed calculated in step S43 is
greater than or equal to the third threshold (Yes in step S44), the determiner 61 transmits
37
a notice of a slip to the power conversion circuit controller 86 (step S45).
[0127] When, for example, all the wheels 15a, 15b, 15c, and 15d slip and none of
the wheels 25a, 25b, 25c, and 25d slips, the axle speed and the reference axle speed
change in the vehicle 100 as illustrated in FIG. 20. In FIG. 20, the solid line indicates
5 changes in the axle speed, and the dotted line indicates changes in the reference axle
speed. In FIG. 20, the horizontal axis indicates time, and the vertical axis indicates
speed. Power running is started at time T11. At time T11, the master controller 5 is
controlled to transmit an operation command including a powering command to the slipand-skid determining devices 35 and 36. At time T11 and subsequent times, the axle
10 speed and the reference axle speed increase at a constant rate based on the target
acceleration.
[0128] All the wheels 15a, 15b, 15c, and 15d slip at time T12. At time T12, the
axle speeds of all the axles 14a, 14b, 14c, and 14d start increasing rapidly. None of the
wheels 25a, 25b, 25c, and 25d slips at time T12 and subsequent times. Thus, the
15 reference axle speed acquired by the slip-and-skid determining device 35 from the slipand-skid determining device 36 increases at a constant rate based on the target
acceleration. Thus, although the axle speeds of all the axles 14a, 14b, 14c, and 14d
rapidly increase, the reference axle speed decider 60 in the slip-and-skid determining
device 35 outputs the reference axle speed that decreases at a constant rate unlike the
20 rapidly increasing axle speed of the axles 14a, 14b, 14c, and 14d.
[0129] For example, the difference between the axle speed of each of the axles 14a,
14b, 14c, and 14d and the reference axle speed reaches the third threshold at time T13.
At time T13, the difference in speed between the axle speed of each of the axles 14a, 14b,
14c, and 14d and the reference axle speed is greater than or equal to the third threshold,
25 causing the determiner 61 in the slip-and-skid determining device 35 to transmit a notice
of a slip to the power conversion circuit controller 86.
[0130] Upon receiving the notice of a slip from the slip-and-skid determining
38
device 35, the power conversion circuit controller 86 sets the torque command value τ* to
a smaller value than the torque command value τ* decided based on the target
acceleration of the railway vehicle 1 indicated by the powering command and the
measurement value of the rotational speed of the electric motor 87. The power
5 conversion circuit controller 86 generates the power conversion control signal based on
the torque command value τ* set to the smaller value.
[0131] When the power conversion control signal generated as described above is
provided to the gate signal for each switching element in the power conversion circuit 84,
the power output from the power conversion circuit 84 decreases and the rotational speed
10 of the electric motor 87 decreases as well. When the rotational speed of the electric
motor 87 decreases and the acceleration is reduced, the difference between the axle speed
of each of the axles 14a, 14b, 14c, and 14d and the reference axle speed starts decreasing.
Subsequently, the difference between the axle speed of each of the axles 14a, 14b, 14c,
and 14d and the reference axle speed reaches zero, thus achieving re-adhesion of the
15 wheels 15a, 15b, 15c, and 15d to the rails at time T14.
[0132] As described above, the slip-and-skid determining device 35 according to
Embodiment 5 decides the reference axle speed based on the axle speed of each of the
axles 14a, 14b, 14c, and 14d in the vehicle 100 and the axle speed of each of the axles
24a, 24b, 24c, and 24d in the other vehicle 200. This prevents the reference axle speed
20 from changing rapidly unlike the axle speed of each of the axles 14a, 14b, 14c, and 14 in
the vehicle 100, although all the wheels 15a, 15b, 15c, and 15d attached to the axles 14a,
14b, 14c, and 14d skid or slip, thus allowing determination of the occurrence of a skid or
a slip of any wheel based on the difference between each axle speed and the reference
axle speed.
25 [0133] Similarly, the slip-and-skid determining device 36 decides the reference axle
speed based on the axle speed of each of the axles 24a, 24b, 24c, and 24d in the vehicle
200 and the axle speed of each of the axles 14a, 14b, 14c, and 14d in the other vehicle
39
100. This allows determination of the occurrence of a skid or slip of any of the wheels
25a, 25b, 25c, and 25d attached to the axles 24a, 24b, 24c, and 24d in the vehicle 200
based on the difference between each axle speed and the reference axle speed, although
all the wheels 25a, 25b, 25c, and 25d skid or slip.
5 [0134] The present disclosure is not limited to the above embodiments. The
above embodiments may be combined as appropriate. For example, the occurrence of a
slip or a skid may be determined in Embodiments 1 to 4 in the same manner as in
Embodiment 5.
[0135] In another example, similarly to the reference axle speed decider 56, the
10 reference axle speed decider 60 in the slip-and-skid determining device 35 according to
Embodiment 5 may decide the reference axle speed that maintains the rate of change in
the reference axle speed within the target range. More specifically, the reference axle
speed decider 60 in FIG. 21 includes a decreased speed outputter 76 that outputs a limit
value of decrease in speed in a calculation cycle, and an increased speed outputter 77 that
15 outputs a limit value of increase in speed in a calculation cycle. The reference axle
speed decider 60 further includes an adder 78 that adds a value output from the increased
speed outputter 77 to the most recently decided reference axle speed, and a minimum
value outputter 79 that outputs a minimum value of values output from the minimum
value outputter 74 and from the adder 78.
20 [0136] The decreased speed outputter 76 outputs, as the above limit value (in
km/h), for example, the decreased speed of the vehicle 100 in each calculation cycle
based on the maximum value of the target deceleration indicated by the braking
command.
[0137] The adder 72 adds the value (in km/h) output from the decreased speed
25 outputter 76 to the most recently decided reference axle speed (in km/h) output from the
switch 75. The value output from the adder 72 corresponds to the axle speed of each of
the axles 14a, 14b, 14c, and 14d that can be achieved in accordance with the maximum
40
value of the target deceleration when no skid occurs.
[0138] The increased speed outputter 77 outputs, as the above limit value (in km/h),
for example, the increased speed of the vehicle 100 in each calculation cycle in
accordance with the maximum value of the target acceleration indicated by the powering
5 command.
[0139] The adder 78 adds the value (in km/h) output from the increased speed
outputter 77 to the most recently decided reference axle speed (in km/h) output from the
switch 75. The value output from the adder 78 corresponds to the axle speed of each of
the axles 14a, 14b, 14c, and 14d that can be achieved based on the maximum value of the
10 target acceleration when no slip occurs.
[0140] The minimum value outputter 79 outputs the minimum value of values
output from the minimum value outputter 74 and from the adder 78.
[0141] The switch 75 outputs the value output from the maximum value outputter
73 when the operation command includes a braking command, and outputs the value
15 output from the minimum value outputter 79 when the operation command does not
include a braking command. The reference axle speed output from the switch 75
changes in each calculation cycle based on the limit value as the upper limit value output
from the decreased speed outputter 76 or output from the increased speed outputter 77.
[0142] In still another example, to prevent the reference axle speed from increasing
20 with a fault in the speed detector 16a, 16b, 16c, or 16d, the slip-and-skid determining
device 13 may have an upper limit value for the reference axle speed. The slip-and-skid
determining device 13 in FIG. 22 includes the maximum value outputter 70 that outputs
the maximum value of speeds that are each axle speed acquired from the axle speed
decider 51 and the reference axle speed acquired from the slip-and-skid determining
25 device 23, an upper speed limit outputter 80 that outputs the upper limit value of the
reference axle speed, and the minimum value outputter 79 that outputs the minimum
value of values output from the maximum value outputter 70 and from the upper speed
41
limit outputter 80. The upper limit value of the reference axle speed may be determined
in accordance with, for example, the maximum speed that can be achieved by the railway
vehicle 1.
[0143] The railway vehicle 1 may include any number of vehicles. The
5 acceleration detector 82 may be located in some vehicles or in each vehicle.
[0144] The reference axle speed deciders 52 and 60 may acquire, instead of the
reference axle speed of the other vehicle 200, the axle speed of each of the axles 24a, 24b,
24c, and 24d in the other vehicle 200.
[0145] The vehicle speed decider 54 may determine the position of the railway
10 vehicle 2 based on radio waves from a global positioning system (GPS) satellite, and may
decide the speed of the vehicle 100 based on a change in the position of the railway
vehicle 2 per unit time.
[0146] Each of the slip-and-skid determining devices 13, 23, 31, 32, 33, 34, 35, and
36 may use the rotational speed of each of the axles 14a, 14b, 14c, and 14d as the
15 corresponding axle speed. For example, the slip-and-skid determining device 13 may
decide the reference axle speed based on the rotational speed of each of the axles 14a,
14b, 14c, and 14d and the rotational speed of each of the axles 24a, 24b, 24c, and 24d.
[0147] The processes performed by the slip-and-skid determining devices 13, 23,
31, 32, 33, 34, 35, and 36 when a skid is determined to have occurred are not limited to
20 the examples described above. When, for example, occurrence of a skid is determined
by the slip-and-skid determining device 13, the target brake force decider 41 in the brake
control device 12 sets the target brake force to a smaller value than the target brake force
decided based on the target deceleration and the load on the vehicle 100. The target
pressure decider 42 decides the target pressure based on the target brake force set to the
25 smaller value. In this state, the slip-and-skid determining devices 13 and 23 transmit or
receive, to or from each other, the determination results. Upon receiving a notice of a
skid in the vehicle 100 from the slip-and-skid determining device 23, the brake control
42
device 12 in the vehicle 200 preferably sets the target brake force to a greater value than
the target brake force decided based on the target deceleration and the load on the vehicle
200. An increase in the braking distance resulting from the skid is thus suppressed.
[0148] The slip-and-skid determining devices 13, 23, 31, 32, 33, 34, 35, and 36
5 may be implemented as one function of the train information management system, or
may be located in a ground equipment, for example, an operation control center.
[0149] The mechanical brake devices in the vehicles 100 and 200 are not limited to
the examples described above. The vehicles 100 and 200 may each include a
mechanical brake device that generates a brake force by pressing a brake pad as a
10 frictional member against a brake disk as a rotor.
[0150] The hardware configurations of the brake control devices 12 and 22 and the
slip-and-skid determining devices 13, 23, 31, 32, 33, 34, 35, and 36 are not limited to the
examples described above. The brake control devices 12 and 22 and the slip-and-skid
determining devices 13, 23, 31, 32, 33, 34, 35, and 36 may be implemented by a
15 processing circuit 94, as illustrated in FIG. 23. The processing circuit 94 is connected to
an external device through an interface circuit 95. For example, the brake control
device 12 is connected to the master controller 5, the load detector 11, the slip-and-skid
determining device 13, and the anti-skid valves 19a, 19b, 19c, and 19d through the
interface circuit 95. The slip-and-skid determining device 13 is connected to the master
20 controller 5, the slip-and-skid determining device 23, and the speed detectors 16a, 16b,
16c, and 16d through the interface circuit 95.
[0151] When the processing circuit 94 is dedicated hardware, the processing circuit
94 includes, for example, a single circuit, a complex circuit, a processor, an applicationspecific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a
25 combination of two or more of these. Each component of the brake control devices 12
and 22 and each component of the slip-and-skid determining devices 13, 23, 31, 32, 33,
34, 35, and 36 may be implemented by an individual processing circuit 94 or a shared
43
processing circuit 94.
[0152] Some of the functions of the brake control devices 12 and 22 and the slipand-skid determining devices 13, 23, 31, 32, 33, 34, 35, and 36 may be implemented by
dedicated hardware, and others may be implemented by software or firmware. For
5 example, in the slip-and-skid determining device 13, the processing circuit 94 in FIG. 23
may implement the functions of the axle speed decider 51 and the reference axle speed
decider 52, and the processor 91 in FIG. 4 reads and executes the programs stored in the
memory 92 to implement the functions of the determiner 53.
[0153] The foregoing describes some example embodiments for explanatory
10 purposes. Although the foregoing discussion has presented specific embodiments,
persons skilled in the art will recognize that changes may be made in form and detail
without departing from the broader spirit and scope of the invention. Accordingly, the
specification and drawings are to be regarded in an illustrative rather than a restrictive
sense. This detailed description, therefore, is not to be taken in a limiting sense, and the
15 scope of the invention is defined only by the included claims, along with the full range of
equivalents to which such claims are entitled.
Reference Signs List
[0154]
1, 2 Railway vehicle
20 5 Master controller
10, 20 Brake control system
11, 21 Load detector
12, 22 Brake control device
13, 23, 31, 32, 33, 34, 35, 36 Slip-and-skid determining device
25 14a, 14b, 14c, 14d, 24a, 24b, 24c, 24d Axle
15a, 15b, 15c, 15d, 25a, 25b, 25c, 25d Wheel
16a, 16b, 16c, 16d, 26a, 26b, 26c, 26d Speed detector
44
17a, 17b, 17c, 17d, 27a, 27b, 27c, 27d Brake block
18a, 18b, 18c, 18d, 28a, 28b, 28c, 28d Brake cylinder
19a, 19b, 19c, 19d, 29a, 29b, 29c, 29d Anti-skid valve
41 Target brake force decider
5 42 Target pressure decider
43 Output valve
44 Pressure sensor
45 Electro-pneumatic conversion valve
46 Relay valve
10 47 Re-adhesion controller
51 Axle speed decider
52, 55, 56, 60 Reference axle speed decider
53, 59, 61 Determiner
54 Vehicle speed decider
15 57 Axle acceleration decider
58 Acceleration difference calculator
70, 73 Maximum value outputter
71 Acceleration converter
72, 78 Adder
20 74, 79 Minimum value outputter
75 Switch
76 Decreased speed outputter
77 Increased speed outputter
80 Upper speed limit outputter
25 81 Fluid source
82 Acceleration detector
83 Power converter
45
83a, 83b Input terminal
84 Power conversion circuit
85 Current detection circuit
86 Power conversion circuit controller
5 87 Electric motor
90 Bus
91 Processor
92 Memory
93 Interface
10 94 Processing circuit
95 Interface circuit
100, 200 Vehicle
C1 Capacitor
L1 Reactor

We Claim :
[Claim 1] A slip-and-skid determining device, comprising:
an axle speed decider to decide, for each of a plurality of axles in a vehicle of one
or more vehicles included in a railway vehicle, an axle speed changeable in accordance
5 with a rotational speed of a wheel attached to each of the plurality of axles in the vehicle;
a reference axle speed decider to decide, based on the axle speed of each of the
plurality of axles in the vehicle and a physical quantity changeable during travel of the
railway vehicle, a reference axle speed in the vehicle; and
a determiner to determine, based on comparison between the axle speed and the
10 reference axle speed, whether any slip or skid of the wheel occurs.
[Claim 2] The slip-and-skid determining device according to claim 1, wherein
the one or more vehicles is a plurality of the vehicles,
the reference axle speed decider decides the reference axle speed based on the axle
15 speed of each of the plurality of axles in the vehicle and an axle speed of each of a
plurality of axles in another vehicle of the plurality of vehicles.
[Claim 3] The slip-and-skid determining device according to claim 2, wherein
the reference axle speed decider selects, as the reference axle speed, a maximum
20 value of speeds that are the axle speed of each of the plurality of axles in the vehicle and
the axle speed of each of the plurality of axles in the another vehicle, and
the determiner determines, based on comparison between the axle speed and the
reference axle speed, whether any skid of the wheel occurs.
25 [Claim 4] The slip-and-skid determining device according to claim 2, wherein
the reference axle speed decider selects, as the reference axle speed, a minimum
value of the axle speed of each of the plurality of axles in the vehicle and the axle speed
47
of each of the plurality of axles in the another vehicle, and
the determiner determines, based on comparison between the axle speed and the
reference axle speed, whether any slip of the wheel occurs.
5 [Claim 5] The slip-and-skid determining device according to claim 1, wherein
the reference axle speed decider decides the reference axle speed based on the axle
speed of each of the plurality of axles in the vehicle and a speed of the railway vehicle.
[Claim 6] The slip-and-skid determining device according to claim 5, wherein
10 the reference axle speed decider selects, as the reference axle speed, a maximum
value of speeds that are the axle speed of each of the plurality of axles in the vehicle and
the speed of the railway vehicle, and
the determiner determines, based on comparison between the axle speed and the
reference axle speed, whether any skid of the wheel occurs.
15
[Claim 7] The slip-and-skid determining device according to claim 5, wherein
the reference axle speed decider selects, as the reference axle speed, a minimum
value of the axle speed of each of the plurality of axles in the vehicle and the speed of the
railway vehicle, and
20 the determiner determines, based on comparison between the axle speed and the
reference axle speed, whether any slip of the wheel occurs.
[Claim 8] The slip-and-skid determining device according to any one of claims
1 to 7, wherein
25 the reference axle speed decider decides the reference axle speed that maintains a
rate of change in the reference axle speed within a target range.
48
[Claim 9] The slip-and-skid determining device according to claim 8, wherein
the reference axle speed decider decides the reference axle speed that maintains the
rate of change in the reference axle speed within the target range defined based on an
acceleration of the railway vehicle.
5
[Claim 10] The slip-and-skid determining device according to any one of claims
1 to 9, further comprising:
an axle acceleration decider to decide an axle acceleration based on the axle speed,
wherein the determiner determines, based on comparison between the axle speed
10 and the reference axle speed or comparison between the axle acceleration and an
acceleration of the railway vehicle, whether any slip or skid of the vehicle occurs.
[Claim 11] The slip-and-skid determining device according to any one of claims
1 to 10, wherein
15 the axle speed decider decide, based on the rotational speed of the wheel attached
to each of the plurality of axles, the axle speed corresponding to a circumferential speed
of the wheel.
[Claim 12] A brake control system, comprising:
20 a brake control device to control, in accordance with a braking command
indicating a target deceleration being a target value for a deceleration of the railway
vehicle, a mechanical brake device provided for each of a plurality of wheels in a vehicle
of one or more vehicles included in a railway vehicle, the mechanical brake device being
configured to decelerate braking command the vehicle by pressing a frictional member
25 against a rotor rotating during travel of the railway vehicle based on pressure of a fluid
supplied; and
the slip-and-skid determining dvice according to any one of claims 1 to 11,
49
wherein the brake control device includes
a target brake force decider to acquire the braking command and decide a
target brake force being a brake force to achieve the target deceleration,
a target pressure decider to decide, based on the target brake force, a target
5 pressure being a target value for the pressure of the fluid to be supplied to the mechanical
brake device,
an output valve to compress the fluid supplied from a fluid source in
accordance with the target pressure and supply the compressed fluid to the mechanical
brake device, and
10 a re-adhesion controller to reduce, when a determination result is received
from the slip-and-skid determining device and the determiner in the slip-and-skid
determining device determines that a skid of at least one wheel of the plurality of wheels
occurs, the brake force generated by the mechanical brake device corresponding to the at
least one wheel for which the occurrence of skid is determined by the determiner.
15
[Claim 13] A slip-and-skid determining method, comprising:
deciding, for each of a plurality of axles in a vehicle of one or more vehicles
included in a railway vehicle, an axle speed changeable in accordance with a rotational
speed of a wheel attached to each of the plurality of axles in the vehicle;
20 deciding a reference axle speed in the vehicle based on the axle speed of each of
the plurality of axles in the vehicle and a physical quantity changeable during travel of the
railway vehicle; and
determining, based on comparison between the axle speed and the reference axle
speed, whether any slip or skid of the wheel occurs