U.S. patent application number 13/618093 was filed with the patent office on 2014-03-20 for rollback protection system and method.
The applicant listed for this patent is Ralph C. Haddock, III, Robert Carmen PALANTI, Derek Kevin Woo. Invention is credited to Ralph C. Haddock, III, Robert Carmen PALANTI, Derek Kevin Woo.
Application Number | 20140081486 13/618093 |
Document ID | / |
Family ID | 50263148 |
Filed Date | 2014-03-20 |
United States Patent
Application |
20140081486 |
Kind Code |
A1 |
PALANTI; Robert Carmen ; et
al. |
March 20, 2014 |
ROLLBACK PROTECTION SYSTEM AND METHOD
Abstract
A method for preventing rollback of a rail vehicle from a
stopped condition, includes receiving a first signal indicative of
the rail vehicle's location, and, in response to the first signal,
selecting from a lookup table one of a first plurality of
pre-determined values of a braking parameter and selecting from the
lookup table one of a second plurality of pre-determined values of
a tractive effort parameter. In response to an order for movement,
the method includes applying brakes of the rail vehicle, according
to the selected value of the braking parameter; establishing
tractive effort of the rail vehicle, according to the selected
value of the tractive effort parameter; and, then, releasing the
brakes of the rail vehicle to establish motion of the rail vehicle
from the stopped condition.
Inventors: |
PALANTI; Robert Carmen;
(Melbourne, FL) ; Woo; Derek Kevin; (Melbourne,
FL) ; Haddock, III; Ralph C.; (Melbourne,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PALANTI; Robert Carmen
Woo; Derek Kevin
Haddock, III; Ralph C. |
Melbourne
Melbourne
Melbourne |
FL
FL
FL |
US
US
US |
|
|
Family ID: |
50263148 |
Appl. No.: |
13/618093 |
Filed: |
September 14, 2012 |
Current U.S.
Class: |
701/19 ; 246/184;
246/186 |
Current CPC
Class: |
B61L 25/023 20130101;
B61L 15/0027 20130101; B61L 27/0077 20130101; B61L 3/127 20130101;
B61L 17/00 20130101 |
Class at
Publication: |
701/19 ; 246/186;
246/184 |
International
Class: |
B61L 3/00 20060101
B61L003/00 |
Claims
1. (canceled)
2. A system for controlling a rail vehicle, comprising: an
off-board control unit that is configured for communication with an
on-board transceiver, the on-board transceiver being mounted in the
rail vehicle, the off-board control unit further configured to, in
case the rail vehicle is stopped, receive a first signal indicative
of a location of the rail vehicle and further configured to, in
response to the indicated location of the rail vehicle matching a
pre-defined list of rollback locations, send to the on-board
transceiver a second signal indicative of a tractive effort
parameter and a braking parameter, said parameters corresponding to
at least the indicated location of the rail vehicle; and the
on-board transceiver, wherein the on-board transceiver is
configured to adjust and monitor a tractive effort of the rail
vehicle and to control applying brakes of the rail vehicle,,
according to the braking parameter, until the monitored tractive
effort at least matches the tractive effort parameter, is further
configured to release the brakes after the monitored tractive
effort matches the tractive effort parameter, and is further
configured to, after releasing the brakes, monitor rail vehicle
movement, compare the monitored movement to an ordered movement,
and in response to a mismatch of the monitored movement and the
ordered movement, transmit to the off-board control unit a third
signal related to applying the brakes of the rail vehicle.
3. (canceled)
4. A system as claimed in claim 2, wherein the on-board transceiver
is configured to monitor rail vehicle movement, to compare the
monitored movement to an ordered movement, and to control
application of emergency brakes in response to a mismatch of the
monitored movement and the ordered movement.
5. A system as claimed in claim 4, wherein the off-board control
unit is configured to set a braking parameter based on the
indicated location of the rail vehicle, and the on-board
transceiver is configured to control application of the emergency
brakes according to the braking parameter.
6. A system as claimed in claim 4, wherein the on-board transceiver
is configured to compare the monitored movement to the ordered
movement on a time integral basis.
7. (canceled)
8. A system as claimed in claim 2, wherein the off-board control
unit is configured to, in response to the third signal generated by
the on-board transceiver, display an operator prompt and receive an
operator input whether to apply the brakes.
9. A system as claimed in claim 2, wherein the off-board control
unit is configured to set a braking parameter based on the
indicated location of the rail vehicle, and to send a fourth signal
for applying the brakes, wherein the fourth signal for applying the
brakes includes the braking parameter.
10. A system as claimed in claim 2, wherein the off-board control
unit is configured to monitor tractive effort of the rail vehicle,
and to send the on-board transceiver a fourth signal for releasing
the brakes, once the tractive effort of the rail vehicle matches or
exceeds the tractive effort parameter.
11. A system as claimed in claim 10, wherein the off-board control
unit is configured to send the fourth signal for releasing the
brakes, pursuant to a request received from the on-board
transceiver.
12. A system as claimed in claim 2, wherein the off-board control
unit is configured to send a fifth signal for establishing a
rollback prevention mode, based on the indicated location of the
rail vehicle matching the pre-defined list of rollback locations,
and the on-board transceiver is configured to establish a rollback
prevention mode on receipt of the fifth signal from the off-board
control unit.
13. A method for preventing rollback of a rail vehicle starting
from a stopped condition, said method comprising: receiving in an
off-board control unit a first signal indicative of the rail
vehicle's location; in response to the first signal, in the
off-board control unit selecting by a computer algorithm one of a
first plurality of pre-determined values of a braking parameter and
selecting by a computer algorithm one of a second plurality of
pre-determined values of a tractive effort parameter; transmitting
from the off-board control unit to an onboard transceiver of the
rail vehicle a second signal ordering movement of the rail vehicle
from the stopped condition, wherein the second signal comprises the
selected value of the braking parameter for controlling application
of brakes of the rail vehicle and the selected value of the
tractive effort parameter for establishing tractive effort of the
rail vehicle; receiving the second signal at the onboard
transceiver; and, by the onboard transceiver, in response to the
second signal: applying the brakes of the rail vehicle, according
to the selected value of the braking parameter; establishing the
tractive effort of the rail vehicle, according to the selected
value of the tractive effort parameter; releasing the brakes of the
rail vehicle to establish movement of the rail vehicle from the
stopped condition; by the onboard transceiver, after releasing the
brakes, monitoring rail vehicle movement, comparing the monitored
movement to an ordered movement, and in response to a mismatch of
the monitored movement and the ordered movement, transmitting to
the off-board control unit a third signal related to applying the
brakes of the rail vehicle.
14. A method according to claim 13, wherein the third signal is a
request to the off-board control unit for permission to apply the
brakes.
15.-16. (canceled)
17. A system for controlling a rail vehicle, said system
comprising: an on-board transceiver mounted in the rail vehicle and
operatively connected with at least one traction motor and at least
one brake of the rail vehicle, said on-board transceiver configured
to receive from an off-board control unit a first signal for
establishing a rollback prevention mode, and further configured in
said rollback prevention mode to receive from the off-board control
unit a second signal indicative of a required tractive effort and a
third signal indicative of a required braking force, to control
maintaining the required braking force until attaining the required
tractive effort, to control release of the braking force on
attaining the required tractive effort, to monitor movement of the
rail vehicle, to compare the monitored movement to an ordered
movement, and to, in response to a mismatch of the monitored
movement and the ordered movement, transmit to the off-board
control unit a third signal related to applying the brakes of the
rail vehicle.
18. (canceled)
19. A system as claimed in claim 17, wherein the on-board
transceiver is configured to compare the monitored movement to the
ordered movement on a time integral basis.
20. A system for controlling a rail vehicle, comprising: an
off-board control unit that is configured to receive a first signal
indicative of a location of the rail vehicle and to send, in
response to the first signal, a second signal indicative of a
minimum tractive effort parameter and a third signal indicative of
a braking parameter; and an on-board transceiver mounted in the
rail vehicle, operatively connected with at least one traction
motor and at least one brake of the rail vehicle, and configured to
receive the second and third signals from the off-board control
unit, wherein the on-board transceiver is configured to control
maintaining the brake output at or above a level of the braking
parameter until the traction motor output at least matches a level
of the minimum tractive effort parameter, is configured to release
the brake output after the traction motor output matches the
minimum tractive effort parameter, is configured to monitor rail
vehicle movement, and is configured to, in response to a mismatch
between the monitored movement and an ordered movement, transmit to
the off-board control unit a third signal related to applying the
brakes of the rail vehicle.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] Embodiments of the invention relate generally to control
systems for rail vehicles.
[0003] 2. Discussion of Art
[0004] Rail car switching, shunting, and classification are
integral aspects of rail freight operations. These procedures are
performed in switching yards or classification yards, which include
multiple rail tracks branching from one or more lead tracks and
joining together at one or more exits. To maximize operational
efficiency, several cars or trains of cars are typically moving
simultaneously along different branches within a yard. Due to the
presence of multiple stationary rail cars or stub trains on
intervening tracks, an operator in a locomotive moving on a first
track may not be able to see moving cars on a track branching from
the first track. Accordingly, locomotive operators may coordinate
their actions via a yardmaster stationed in a control tower
overlooking the yard.
[0005] Three-way communication between operators and a yardmaster
can potentially introduce lag time and error, which are undesirable
while moving multiple pieces of heavy rail equipment. As such, some
yards include systems by which a yardmaster may remotely control
and coordinate movement of multiple stub trains ("tower control
systems").
[0006] In situations where the train may be on a grade (as may be
found in connection with mining operations), there is a known
tendency for "rollback" where the train moves opposite the applied
tractive power. While rollback can often be quickly detected and
corrected by an onboard operator, the phenomenon is more difficult
to detect and slower to correct from a remote location such as
would be occupied by a tower control system operator. Yet as
discussed above, rail yard operations, generally, can be
accomplished more efficiently by a tower control system operator
than by an onboard crew. As will be appreciated, it is inefficient
and undesirable to continuously crew a train in a rail yard, solely
for the purpose of preventing rollback, particularly where the
onboard crew might otherwise interfere with tower control system
operation. As such, it is desirable to provide a tower control
system that includes a specific and automated method to prevent
rollback.
BRIEF DESCRIPTION
[0007] In embodiments, a system for controlling a rail vehicle
includes an off-board control unit that is configured for
communication with an on-board transceiver, which is mounted in the
rail vehicle. The off-board control unit is further configured to
receive a first signal indicative of a location of the rail vehicle
and to, in response to the indicated location of the rail vehicle
matching a pre-defined list of rollback locations, send to the
on-board transceiver a second signal indicative of a tractive
effort parameter corresponding to at least the indicated location
of the rail vehicle.
[0008] In aspects, a method, e.g., a method for preventing rollback
of a rail vehicle from a stopped condition, includes receiving a
first signal indicative of the rail vehicle's location and, in
response to the first signal, selecting from a lookup table one of
a first plurality of pre-determined values of a braking parameter
and selecting from the lookup table one of a second plurality of
pre-determined values of a tractive effort parameter. The method
then includes transmitting to the rail vehicle a second signal
ordering movement of the rail vehicle from the stopped condition.
The second signal includes the selected value of the braking
parameter for controlling application of brakes of the rail vehicle
and the selected value of the tractive effort parameter for
establishing tractive effort of the rail vehicle.
[0009] In embodiments, a system for controlling a rail vehicle
includes an on-board transceiver mounted in the rail vehicle and
operatively connected with at least one traction motor and at least
one brake of the rail vehicle. The on-board transceiver is
configured to receive from an off-board control unit a first signal
for establishing a rollback prevention mode. In its rollback
prevention mode, the on-board transceiver is configured to receive
from the off-board control unit a second signal indicative of a
required tractive effort and a third signal indicative of a
required braking force, and to control maintaining the required
braking force until attaining the required tractive effort.
[0010] In embodiments, a system for controlling a rail vehicle
includes an off-board control unit that is not mounted in the rail
vehicle and an on-board transceiver that is mounted in the rail
vehicle. The off-board control unit is configured to receive a
first signal indicative of a location of the rail vehicle and to
send, in response to the first signal, a second signal indicative
of a minimum tractive effort parameter and a third signal
indicative of a braking parameter. The on-board transceiver is
operatively connected with at least one traction motor and at least
one brake of the rail vehicle, and is configured to receive the
second and third signals from the off-board control unit. The
on-board transceiver is further configured to control maintaining
the brake output at or above a level of the braking parameter until
the traction motor output at least matches a level of the minimum
tractive effort parameter.
DRAWINGS
[0011] The present invention will be better understood from reading
the following description of non-limiting embodiments, with
reference to the attached drawings, wherein below:
[0012] FIG. 1 shows in schematic view a bulk cargo
loading/unloading operation including a tower control system
according to one aspect of the present invention.
[0013] FIG. 2 shows in schematic view a rollback phenomenon.
[0014] FIG. 3 shows in schematic view a tower control system
according to an embodiment of the present invention.
[0015] FIG. 4 shows in schematic view details of the tower control
system shown in FIG. 3.
[0016] FIG. 5 shows in schematic view operation of the tower
control system shown in FIGS. 3 and 4.
[0017] FIGS. 6A-6C show in schematic view a rollback prevention
mode of the tower control system, according to aspects of the
present invention.
[0018] FIG. 7 shows in schematic view a rollback prevention mode of
the tower control system, according to other aspects of the present
invention.
[0019] FIGS. 8A-8B show in schematic view another rollback
prevention mode of the tower control system, according to other
aspects of the present invention.
DETAILED DESCRIPTION
[0020] Reference will be made below in detail to exemplary
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
characters used throughout the drawings refer to the same or like
parts. Although exemplary embodiments of the present invention are
described with respect to rail vehicles within a rail yard,
embodiments of the invention are also applicable for use with rail
vehicles, generally.
[0021] FIG. 1 shows in schematic view a bulk cargo
loading/unloading operation 10 that includes a loop (or other
section) of track 12 connected from a main rail line 14 through
loading/unloading equipment 16. In the loading/unloading equipment
16, coal/iron ore/other bulk products are dumped into or out of
cars or wagons 18 of a train or other rail vehicle consist 20 that
is located at a location on the loop of track 12. (A rail vehicle
consist is a group of rail vehicles that are mechanically linked to
travel together along a track.) For example, the loading/unloading
equipment 16 may include a dumper chute (which directs a continuous
flow of bulk material into a wagon positioned below the chute) or a
rotary dumper cage (which inverts a wagon positioned in the dumper
cage).
[0022] When the rail vehicle consist 20 approaches the unloading
equipment 16, each wagon 18 is in turn moved into position by
indexing equipment 22. Once a wagon 18 is positioned, independent
and/or automatic brakes are set to hold the rail vehicle consist 20
at a fixed location. ("Independent brakes" means the brakes of each
locomotive or other powered rail vehicle 24 (rail vehicle capable
of self propulsion) within the rail vehicle consist 20, which can
be controlled independently of the "automatic brakes" that are
installed on each wagon 18. The automatic brakes installed on the
wagons 18 are operable all together and are also referred to as
"train brakes." Together, the independent and automatic brakes
compose a "braking system," which may be operated all together or
piece by piece.)
[0023] In order to move the whole rail vehicle consist 20 forward,
so as to bring a next wagon 18 into position, the brakes must be
released while tractive power is applied when all or part of the
rail vehicle consist 20 is located on a grade or incline, then
rollback (as shown schematically in FIG. 2) can be caused by the
weight of the rail vehicle consist 20 exceeding the instantaneous
torque provided by electric traction motors. Once rollback starts
to happen, increasing backward movement 611 of the rail vehicle
consist 20 requires increasingly larger forward torque (ordered
movement 515) in order to stop the rail vehicle consist.
Frequently, brakes must be reapplied and another attempt must be
made at forward motion.
[0024] Rollback of the rail vehicle consist 20, as illustrated
schematically in FIG. 2, can lead to impacts between the rail
vehicle consist 20 and the loading/unloading equipment 16. Rollback
also can lead to a condition where the rail vehicle consist 20
rests against the loading/unloading equipment 16 with sufficient
force to interfere with operation of the equipment. Such impacts or
interferences can damage the rail vehicle consist and/or the
loading/unloading equipment, causing repair expense and
downtime.
[0025] With reference to FIG. 3, aspects of the invention relate to
a system for controlling a rail vehicle 24a, by which rollback of
the rail vehicle is prevented. In particular aspects, the system
includes an on-board transceiver 202 of the rail vehicle 24a. The
on-board transceiver 202 sends and receives signals in
communication with an off-board control unit 204. The on-board
transceiver 202 also includes hardware and software for controlling
operation of the rail vehicle 24a. In particular, the on-board
transceiver 202 is operatively connected for controlling traction
and braking of the rail vehicle 24a. The on-board transceiver 202
can be configured in various modes of operation. For example, in a
rollback prevention mode, the on-board transceiver 202 adjusts
traction motors 206 of the rail vehicle 24a to achieve a
pre-determined minimum tractive effort prior to releasing a braking
system 208 of the rail vehicle.
[0026] FIG. 4 illustrates details of a tower control system 200
according to embodiments of the invention. The tower control system
may include a tower equipment module 210 that houses a tower
transceiver 212 for intermediating communication between the
off-board control unit 204 and the on-board transceiver 202. The
tower equipment module also may house an integrated processor
module (IPM) 214 and a power converter 216. In some embodiments,
the power converter receives 120 Vac and supplies 13.6 and 72
Vdc.
[0027] As shown in FIG. 4, according to one embodiment of the
invention, the off-board control unit 204 includes multiple
displays 218 on which a desired speed setting and measured vehicle
speed are shown, as well as an operator control unit (OCU) 220.
Each display is a remote session based device connected to the IPM
214, which handles all control signals and consist data for the
operator displays 218. The OCU 220 includes at least the following
controls: a multi-position selector 222 as well as a PARK button
224 and a STOP button 226. In some embodiments, the OCU also may
include an auxiliary display 228 as shown. In some embodiments, the
selector 222 may include a dial, a switch, a position encoder, or
any equivalent device suitable for selecting among more than two
options. In some embodiments, the buttons 224, 226 may be
spring-return push buttons. Toggle switches, sliders, or the like
are equally suitable. In certain embodiments, the functions of the
two buttons 224, 226 may be combined into a single component, for
example, a three-way selector switch. In select embodiments the
functions of the two buttons 224, 226 may be combined into the
selector 222, or the buttons may be mounted on the selector. The
selector 222 as well as the buttons 224, 226 and the optional
display 228 are shown and described herein as being physically
separate components within an assembled unit, however, one of
ordinary skill will appreciate that the displays 218 and the OCU
220 equally can be implemented partly or entirely via a single
advanced interface such as a touch-screen.
[0028] The displays 218, 228 and the OCU 220 are coordinated by a
computing device 230. "Computing device" as used herein refers to
either a general purpose integrated circuit, a custom ASIC, an
FPGA, a custom analog circuit, or other like device. As shown in
FIG. 3, the computing device 230 is connected with the integrated
processor module 214 via a point-to-point high-level data link
control ("HDLC") layer. In certain embodiments, the functionality
of the computing device 230 may be implemented in the IPM 214
itself.
[0029] As illustrated in FIG. 5, the computing device 230 is
configured to implement a continuous-loop control process 400 for
generating and sending commands 407 to the on-board transceiver 202
via the IPM 214 and the tower transceiver 212. In implementation of
the process 400, the computing device 230 makes use of a working
memory 401. The working memory 401 may be composed of any
electronically or optically read-writeable media, such as EEPROM,
NAND flash, SDRAM, a hard drive, an optical disc, vacuum tubes, a
capacitor bank, or other equivalent structures apparent to those of
ordinary skill.
[0030] Each iteration of the process 400 includes a step 402 of
checking and setting a mode of operation 403 of the off-board
control unit 204. For example, pressing one of the STOP button 224
or the PARK button 226 establishes a corresponding mode of
operation 403 of the off-board control unit 204 that causes the
computing device 230 to generate and send to the on-board
transceiver 202, via the tower transceiver 212, commands that idle
the traction power system and that order braking of a locomotive 24
(or other powered rail vehicle) or of the entire rail vehicle
consist 20, respectively.
[0031] After checking the mode of operation, the process 400
proceeds to a step 404 of receiving signals from the on-board
transceiver 202 and/or from other sources within the rail yard 10
including the unloading equipment 16 or the indexing equipment 22.
(Here "rail yard" is meant to include any arrangement of tracks off
of a main line, including humpyards, sorting yards, or
loading/unloading operations as discussed above.)
[0032] The computing device 230 stores received signals in the
working memory 401 as on-board data 405. The on-board data 405 may
include a measured speed "M" as well as indications that braking
has been applied or that a braking order has been received in the
rail vehicle where the on-board transceiver is installed. The
measured speed "M" may be obtained by the on-board transceiver 202
from a control system on some rail vehicles (e.g., a locomotive
control system on some locomotives) or from a trainline interface
module (TIM) on some other locomotives or other rail vehicles.
[0033] Next, at a step 406 the computing device 230 generates
commands 407 to be sent to the on-board transceiver. The commands
407 are generated according to an algorithm, which corresponds to
the mode of operation 403. The algorithm generates the commands 407
with reference to the on-board data 405 and further with reference
to control data and internal signals 408 that are stored in the
working memory 401. Exemplary modes of operation 403, and on-board
data 405, have been discussed above. The control data and internal
signals 408 may include the braking parameter "P", a preset speed
limit "L", a selector position "H", and an ordered speed "O". At a
step 410 the tower control system 200 then sends the commands 407
to the on-board transceiver 202 before looping back to again check
for control data input from the off-board control unit 204.
[0034] According to aspects of the present invention, the computing
device 230 is configured to establish a rollback prevention mode of
operation and to execute a first algorithm 500, as shown in FIG.
6A, in response to the lead locomotive 24a (or other lead powered
rail vehicle) being halted at any location within one or more
pre-determined areas of the rail yard 10. As part of the first
algorithm 500, the computing device 230 directs the on-board
transceiver 202 to execute a second algorithm 600, as shown in FIG.
6B. Thus, the two FIGS. 5 and 6 should be considered together.
[0035] FIG. 6A shows that at step 502 of the algorithm 500, the
computing device 230, within the off-board control unit 204, checks
whether the lead locomotive 24a (or other lead powered rail
vehicle) is stopped. If not, the computing device 230 will exit the
algorithm. At step 504, the computing device 230 receives a signal
505 indicative of the location of the lead locomotive 24a (or other
lead powered rail vehicle), and compares the indicated location to
a rollback prevention map or table 506. In case the indicated
location is not within the mapped area or is not listed in the
table, then the computing device 230 exits the algorithm 500.
However, in case the indicated location is mapped on the rollback
prevention map 504, or listed in an rollback prevention locations
lookup table, then at step 508 the computing device 230 inserts a
rollback prevention mode signal into the commands 407. This signal
initiates in the on-board transceiver 202 a rollback prevention
mode 600, as shown in FIG. 6. Under the rollback prevention mode
600, the on-board transceiver 202 is configured to receive certain
additional signals from the off-board control unit 204, as
follows.
[0036] Still referring to FIG. 6A, at step 510, the computing
device 230 accesses the rollback prevention map 504, or an
equivalent lookup table, to find a minimum tractive effort
parameter 511 corresponding to the location 501. For example, the
minimum tractive effort parameter 511 may be determined during
commissioning of the tower control system 200. The computing device
230 then inserts into the commands 407 a signal that encodes the
minimum tractive effort parameter 511.
[0037] At step 512, the computing device 230 accesses the rollback
prevention map 504, or an equivalent lookup table, to find a
braking parameter 513 corresponding to the location 501. For
example, the braking parameter 513 may be determined during
commissioning of the tower control system 200. The computing device
230 then inserts into the commands 407 a signal that encodes the
braking parameter 515.
[0038] At step 514 the computing device 230 receives from the
multi-position selector 222 a signal ordering movement of the lead
locomotive 24a (or other lead powered rail vehicle). The computing
device 230 generates an ordered movement 515 and forwards a
corresponding signal to the on-board transceiver 202. The computing
device 230 then proceeds to step 516 of waiting to receive on-board
transceiver status signals 601.
[0039] Referring to FIG. 6B, at step 602, the on-board transceiver
202 receives the rollback prevention mode signal. At step 604, the
on-board transceiver 202 receives the minimum tractive effort
parameter 511 and the braking parameter 513. At step 605, the
on-board transceiver 202 applies at least the brakes of the lead
locomotive 24a (or other lead powered rail vehicle), and possibly
additional brakes of the rail vehicle consist 20, according to the
braking parameter 513. At step 606, the on-board transceiver 202
receives the ordered movement 515 and increments a throttle notch
setting ("throttle up") until a monitored tractive effort 607
matches the minimum tractive effort parameter 511. Then at step
608, the on-board transceiver 202 releases at least the brakes 208
of the lead locomotive 24a (or other lead powered rail vehicle). At
step 608 the on-board transceiver 202 also releases any other
brakes that are applied, for example, the automatic brakes of the
rail vehicle consist 20 in case the rail vehicle consist is in a
parked condition Immediately the on-board transceiver 202 proceeds
to step 610 of checking whether the ordered movement 515
corresponds to a monitored movement 611, which includes a direction
of motion as well as the measured speed "M" that was discussed with
reference to FIG. 4.
[0040] In case the monitored movement 611 is matched with the
ordered movement 515, then the on-board transceiver 202 declares a
"movement" status signal at step 612. In case the monitored
movement 611 does not match the ordered movement 515, then at step
614 the on-board transceiver 202 declares a "rollback" status
signal and proceeds to apply automatic and independent brakes
("emergency braking") at step 616.
[0041] In some embodiments, step 610 of checking for a match is
accomplished by instantaneous or "snapshot" comparison of the
directions of measured movement 611 and ordered movement 515. Thus,
for example, in case the speed of ordered movement 515 is +0.5 mph
(+0.2 m/s), while the monitored movement 611 is -0.2 mph (-0.09
m/s) (directions do not match), then a rollback is declared.
[0042] In other embodiments, step 610 is accomplished in a first
noise-managed mode by comparing ordered movement 515 to monitored
speed and direction 611 on a time integral basis, using one or more
threshold value criteria. That is, referring to FIG. 6C, monitored
movement 611 is continually compared to a first threshold value
630. In case the first threshold value is exceeded, at step 632 the
monitored movement 611 is integrated over a pre-determined period
634 to produce a cumulative traveled distance 636, while at step
638 the ordered movement is integrated over the same period to
produce a cumulative ordered distance 640. Then at step 642 a
second threshold value 644 is compared to the cumulative traveled
distance 636, or to a difference 646 between the cumulative
traveled distance and the cumulative ordered distance 640. For
example, the first threshold value 630 may be as small as -0.02 mph
(0.009 m/s), the pre-determined period 634 may be 10 seconds, while
the second threshold value 644 may be as large as 33 ft (10 m). The
threshold values 630, 644, and the time period 634, are
configurable at least at commissioning of the tower control system
200.
[0043] Referring back to FIG. 6A, in case the signal received at
step 516 indicates proper movement, the computing device 230 exits
the algorithm 500. On the other hand, in case the signal received
at step 516 indicates rollback, the computing device 230 performs
step 518 of displaying an alert.
[0044] FIG. 7 shows more generally the algorithms 500 and 600,
including additional steps 702, 704 of monitoring speed and
direction of the rail vehicle consist 20 as well as optional steps
706, 708 of displaying a braking alert and awaiting an operator
response or confirmation, prior to step 614 of declaring
rollback.
[0045] FIGS. 8A-8B show another implementation of the algorithms
500, 600, wherein certain steps are performed in the computing
device 230, rather than at the on-board transceiver 202. In
particular, FIG. 8A shows that step 606 (throttling up to match the
monitored tractive effort 607 to the minimum tractive effort
parameter 511) and step 608 (releasing brakes) can be accomplished
by remote commands from the off-board control unit 204, rather than
autonomously by the on-board transceiver 202. Meanwhile FIG. 8B
shows that the function of step 610 (comparing ordered movement to
monitored movement) still can be accomplished by the on-board
transceiver 202 using sensors aboard the rail vehicle 24a.
[0046] Thus, in embodiments, a system for controlling a rail
vehicle includes an off-board control unit that is configured for
communication with an on-board transceiver, which is mounted in the
rail vehicle. The off-board control unit is further configured to
receive a first signal indicative of a location of the rail vehicle
and to, in response to the indicated location of the rail vehicle
matching a pre-defined list of rollback locations, send to the
on-board transceiver a second signal indicative of a tractive
effort parameter corresponding to at least the indicated location
of the rail vehicle. In select embodiments, the system may also
include the on-board transceiver, which may be configured to adjust
and monitor a tractive effort of the rail vehicle and to control
applying brakes of the rail vehicle until the monitored tractive
effort at least matches the tractive effort parameter. In such
embodiments, the off-board control unit also may be configured to
set a braking parameter based on the indicated location of the rail
vehicle and to transmit the braking parameter to the on-board
transceiver, while the on-board transceiver may be configured to
control applying the brakes according to the braking parameter.
Further, the on-board transceiver may be configured to monitor rail
vehicle movement, to compare the monitored movement to an ordered
movement, and to control application of emergency brakes in
response to a mismatch of the monitored movement and the ordered
movement. For example, the on-board transceiver may be configured
to control application of the emergency brakes according to the
braking parameter. In select embodiments, the on-board transceiver
may be configured to compare the monitored movement to the ordered
movement on a time integral basis. In some embodiments, the
on-board transceiver also may be configured to send to the
off-board control unit, in response to a mismatch of the monitored
movement and the ordered movement, a request for a third signal to
apply the brakes of the rail vehicle. In such embodiments, the
off-board control unit may be configured to, in response to the
request received from the on-board transceiver, display an operator
prompt and receive an operator input whether to apply the brakes.
The third signal for applying the brakes may include a braking
parameter based on the indicated location of the rail vehicle.
Further, the off-board control unit may be configured to monitor
tractive effort of the rail vehicle, and to send the on-board
transceiver a fourth signal for releasing the brakes, once the
tractive effort of the rail vehicle matches or exceeds the tractive
effort parameter. However, in some embodiments, the off-board
control unit may be configured to send the fourth signal for
releasing the brakes, pursuant to a request received from the
on-board transceiver. In some embodiments, the off-board control
unit may be configured to send a fifth signal for establishing a
rollback prevention mode, based on the indicated location of the
rail vehicle matching the pre-defined list of rollback locations;
the on-board transceiver may be configured to establish a rollback
prevention mode on receipt of the fifth signal from the off-board
control unit.
[0047] In aspects, a method, e.g., a method for preventing rollback
of a rail vehicle from a stopped condition, includes receiving a
first signal indicative of the rail vehicle's location and, in
response to the first signal, selecting from a lookup table one of
a first plurality of pre-determined values of a braking parameter
and selecting from the lookup table one of a second plurality of
pre-determined values of a tractive effort parameter. The method
then includes transmitting to the rail vehicle a second signal
ordering movement of the rail vehicle from the stopped condition.
The second signal includes the selected value of the braking
parameter for controlling application of brakes of the rail vehicle
and the selected value of the tractive effort parameter for
establishing tractive effort of the rail vehicle. In some aspects,
the method also includes receiving the second signal at the rail
vehicle, and, in response to the second signal, applying the brakes
of the rail vehicle, according to the selected value of the braking
parameter; establishing the tractive effort of the rail vehicle,
according to the selected value of the tractive effort parameter;
and, releasing the brakes of the rail vehicle to establish movement
of the rail vehicle from the stopped condition. In certain aspects,
the first signal is received at an off-board control unit that is
not installed on the rail vehicle. In select aspects, the second
signal is transmitted from the off-board control unit to an
on-board transceiver that is installed on the rail vehicle.
[0048] Embodiments include a system for controlling a rail vehicle,
which includes an on-board transceiver mounted in the rail vehicle
and operatively connected with at least one traction motor and at
least one brake of the rail vehicle. The on-board transceiver is
configured to receive from an off-board control unit a first signal
for establishing a rollback prevention mode. In its rollback
prevention mode, the on-board transceiver is configured to receive
from the off-board control unit a second signal indicative of a
required tractive effort and a third signal indicative of a
required braking force, and to control maintaining the required
braking force until attaining the required tractive effort. The
on-board transceiver may be further configured to control release
of the braking force on attaining the required tractive effort, to
monitor movement of the rail vehicle, to compare the monitored
movement to an ordered movement, and to control application of the
required braking force according to the third signal, in case the
monitored movement does not match the ordered movement. In certain
embodiments, the on-board transceiver may be configured to compare
the monitored movement to the ordered movement on a time integral
basis.
[0049] In other embodiments, a system for controlling a rail
vehicle includes an off-board control unit that is not mounted in
the rail vehicle and an on-board transceiver that is mounted in the
rail vehicle. The off-board control unit is configured to receive a
first signal indicative of a location of the rail vehicle and to
send, in response to the first signal, a second signal indicative
of a minimum tractive effort parameter and a third signal
indicative of a braking parameter. The on-board transceiver is
operatively connected with at least one traction motor and at least
one brake of the rail vehicle, and is configured to receive the
second and third signals from the off-board control unit. The
on-board transceiver is further configured to control maintaining
the brake output at or above a level of the braking parameter until
the traction motor output at least matches a level of the minimum
tractive effort parameter.
[0050] It will be appreciated that the invention is not limited by
the preceding description, which is intended to be illustrative,
and not restrictive. For example, the above-described embodiments
(and/or aspects thereof) may be used in combination with each
other. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the invention
without departing from its scope. While the dimensions and types of
materials described herein are intended to define the parameters of
the invention, they are by no means limiting and are exemplary
embodiments. Many other embodiments will be apparent to those of
skill in the art upon reviewing the above description. The scope of
the invention should, therefore, be determined with reference to
the appended claims, along with the full scope of equivalents to
which such claims are entitled. In the appended claims, the terms
"including" and "in which" are used as the plain-English
equivalents of the respective terms "comprising" and "wherein."
Moreover, in the following claims, terms such as "first," "second,"
"third," "fourth," "fifth," "upper," "lower," "bottom," "top," etc.
are used merely as labels, and are not intended to impose numerical
or positional requirements on their objects. Further, the
limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.122, sixth paragraph, unless and until
such claim limitations expressly use the phrase "means for"
followed by a statement of function void of further structure.
[0051] This written description uses examples to disclose several
embodiments of the invention, including the best mode, and also to
enable one of ordinary skill in the art to practice the embodiments
of invention, including making and using any devices or systems and
performing any incorporated methods. The patentable scope of the
invention is defined by the claims, and may include other examples
that occur to one of ordinary skill in the art. Such other examples
are intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
[0052] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Moreover, unless explicitly
stated to the contrary, embodiments "comprising," "including," or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property.
[0053] Since certain changes may be made in the above-described
system and method for rollback prevention, without departing from
the spirit and scope of the invention herein involved, it is
intended that all of the subject matter of the above description or
shown in the accompanying drawings shall be interpreted merely as
examples illustrating the inventive concept herein and shall not be
construed as limiting the invention.
* * * * *