Note: Descriptions are shown in the official language in which they were submitted.
CA 02977730 2017-08-24
GUIDEWAY MOUNTED VEHICLE LOCALIZATION SYSTEM
BACKGROUND
Guideway mounted vehicles include communication train based control
(CTBC) systems to receive movement instructions from wayside mounted devices
adjacent to a guideway. The CTBC systems are used to determine a location and
a
speed of the guideway mounted vehicle. The CTBC systems determine the location
and speed by interrogating transponders positioned along the guideway. The
CTBC
systems report the determined location and speed to a centralized control
system or
to a de-centralized control system through the wayside mounted devices.
The centralized or de-centralized control system stores the location and speed
information for guideway mounted vehicles within a control zone. Based on this
stored
location and speed information, the centralized or de-centralized control
system generates
movement instructions for the guideway mounted vehicles.
When communication between the guideway mounted vehicle and the centralized
or de-centralized control system is interrupted, the guideway mounted vehicle
is braked to a
stop to await a manual driver to control the guideway mounted vehicle.
Communication
interruption occurs not only when a communication system ceases to function,
but also when
the communication system transmits incorrect information or when the CTBC
rejects an
instruction due to incorrect sequencing or corruption of the instruction.
BRIEF DESCRIPTION OF THE DRAWINGS
One or more embodiments are illustrated by way of example, and not by
limitation, in the figures of the accompanying drawings, wherein elements
having the same
reference numeral designations represent like elements throughout. It is
emphasized that, in
accordance with standard practice in the industry various features may not be
drawn to scale
CA 02977730 2017-08-24
and are used for illustration purposes only. In fact, the dimensions of the
various features in
the drawings may be arbitrarily increased or reduced for clarity of
discussion.
Figure 1 is a high level diagram of a fusion sensor arrangement in accordance
with
one or more embodiments;
Figure 2A is a high level diagram of a guideway mounted vehicle including
fusion
sensor arrangements in accordance with one or more embodiments;
Figure 2B is a high level diagram of a guideway mounted vehicle including
fusion
sensor arrangements in accordance with one or more embodiments;
Figure 3 is a flow chart of a method of controlling a guideway mounted vehicle
using a fusion sensor arrangement in accordance with one or more embodiments;
Figure 4 is a functional flow chart for a method of determining a status of a
fusion
sensor arrangement in accordance with one or more embodiments;
Figure 5 is a block diagram of a vehicle on-board controller (VOBC) for using
a
fusion sensor arrangement in accordance with one or more embodiments;
Figure 6 is a block diagram of a system for determining a position of a
guideway
mounted vehicle, in accordance with one or more embodiments;
Figure 7 is a flowchart of a method of determining a position of a guideway
mounted vehicle, in accordance with one or more embodiments;
Figure 8 is a functional flowchart of a method for integrating an Attitude
and Heading Reference System (AHRS) into a VOBC positioning system, in
accordance with one or more embodiments.
Figure 9 is a graph showing experimental results demonstrating the
effectiveness of the system described with respect to Figure 6 at reducing
wheel
calibration errors, in accordance with one or more embodiments.
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Figure 10 is a graph showing experimental results demonstrating the
effectiveness of the system described with respect to Figure 6 at reducing
drift error
in a slide condition, in accordance with one or more embodiments.
DETAILED DESCRIPTION
The following disclosure provides many different embodiments, or examples, for
implementing different features of the invention. Specific examples of
components and
arrangements are described below to simplify the present disclosure. These are
examples and
are not intended to be limiting.
Figure 1 is a high level diagram of a fusion sensor arrangement 100 in
accordance with one
or more embodiments. Fusion sensor arrangement 100 includes a first sensor 110
configured
to receive a first type of information. Fusion sensor arrangement 100 further
includes a
second sensor 120 configured to receive a second type of information different
from the first
type of information. Fusion sensor arrangement 100 is configured to fuse
information
received by first sensor 110 with information received by second sensor 120
using a data
fusion center 130. Data fusion center 130 is configured to determine whether
an object is
detected within a detection field of either first sensor 110 or second sensor
120. Data fusion
center 130 is also configured to resolve conflicts between first sensor 110
and second sensor
120 arising when one sensor provides a first indication and the other sensor
provides a
contradictory indication.
In some embodiments, fusion sensor arrangement 100 is integrated with a
vehicle on-board
controller (VOBC) configured to generate movement instructions for a guideway
mounted
vehicle and to communicate with devices external to the guideway mounted
vehicle. In some
embodiments, fusion sensor arrangement 100 is separate from a VOBC and is
configured to
provide fused data to the VOBC.
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First sensor 110 is configured to be attached to the guideway mounted vehicle.
First sensor
110 includes a first detection field which includes an angular range in both a
horizontal
direction and in a vertical direction. The horizontal direction is
perpendicular to a direction
of travel of the guideway mounted vehicle and parallel to a top surface of a
guideway. The
vertical direction is perpendicular to the direction of travel of the guideway
mounted vehicle
and to the horizontal direction. The angular range in the horizontal direction
facilitates
detection of objects both along the guideway and along a wayside of the
guideway. The
angular range in the horizontal direction also increases a line of sight of
first sensor 110 in
situations where the guideway changes heading. The angular range in the
vertical direction
increases a line of sight of first sensor 110 in situations where the guideway
changes
elevation. The angular range in the vertical direction also facilitates
detection of overpasses
or other height restricting objects.
In some embodiments, first sensor 110 is an optical sensor configured to
capture information
in a visible spectrum. In some embodiments, first sensor 110 includes a
visible light source
configured to emit light which is reflected off objects along the guideway or
the wayside of
the guideway. In some embodiments, the optical sensor includes a photodiode, a
charged
coupled device (CCD), or another suitable visible light detecting device. The
optical sensor
is capable of identifying the presence of objects as well as unique
identification codes
associated with detected objects. In some embodiments, the unique
identification codes
include barcodes, alphanumeric sequences, pulsed light sequences, color
combinations,
geometric representations or other suitable identifying indicia.
In some embodiments, first sensor 110 includes a thermal sensor configured to
capture
information in an infrared spectrum. In some embodiments, first sensor 110
includes an
infrared light source configured to emit light which is reflected off objects
along the
guideway or the wayside of the guideway. In some embodiments, the thermal
sensor
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includes a Dewar sensor, a photodiode, a CCD or another suitable infrared
light detecting
device. The thermal sensor is capable of identifying the presence of an object
as well as
unique identifying characteristics of a detected object similar to the optical
sensor.
In some embodiments, first sensor 110 includes a RADAR sensor configured to
capture
information in a microwave spectrum. In some embodiments, first sensor 110
includes a
microwave emitter configured to emit electromagnetic radiation which is
reflected off objects
along the guideway or the wayside of the guideway. The RADAR sensor is capable
of
identifying the presence of an object as well as unique identifying
characteristics of a
detected object similar to the optical sensor.
In some embodiments, first sensor 110 includes a laser sensor configured to
capture
information within a narrow bandwidth. In some embodiments, first sensor 110
includes a
laser light source configured to emit light in the narrow bandwidth which is
reflected off
objects along the guideway or the wayside of the guideway. The laser sensor is
capable of
identifying the presence of an object as well as unique identifying
characteristics of a
detected object similar to the optical sensor.
In some embodiments, first sensor 110 includes a radio frequency
identification (RFID)
reader configured to capture information in a radio wave spectrum. In some
embodiments,
first sensor 110 includes a radio wave emitter configured to emit an
interrogation signal
which is reflected by objects on the guideway or on the wayside of the
guideway. The RFID
reader is capable of identifying the presence of an object as well as unique
identifying
characteristics of a detected object similar to the optical sensor.
First sensor 110 is configured to identify an object and to track a detected
object. Tracking of
the detected object helps to avoid reporting false positives because rapid
positional changes
of the detected object enable a determination that first sensor 110 is not
operating properly or
that a transitory error occurred within the first sensor.
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Second sensor 120 is configured to be attached to the guideway mounted
vehicle. Second
sensor 120 includes a second detection field which includes an angular range
in both a
horizontal direction and in a vertical direction. In some embodiments, the
second detection
field substantially matches the first detection field in order to reduce a
risk of conflicts
between first sensor 110 and second sensor 120. In some embodiments, the
second detection
field overlaps with a portion of the first detection field.
In some embodiments, second sensor 120 includes an optical sensor, a thermal
sensor, a
RADAR sensor, a laser sensor, or an RFID reader. In some embodiments, second
sensor 120
is a different type of sensor from first sensor 110. For example, in some
embodiments, first
sensor 110 is an optical sensor and second sensor 120 is an RFID reader.
Utilizing first sensor 110 and second sensor 120 capable of detecting
different types of
information, e.g., different electromagnetic spectrums, enables fusion sensor
arrangement 100
to reduce a risk of failing to detect an object along the guideway or the
wayside of the
guideway. Using sensors capable of detecting different types of information
also enables
confirmation of a detected object. For example, an optical sensor detects a
bar code sign
located on a wayside of the guideway. In instances where the bar code is
defaced by dirt or
graffiti such that the optical sensor cannot uniquely identify the bar code
sign, an RFID
reader may still be able to confirm the identifying information of the bar
code sign based on
an RF transponder attached to the bar code sign.
First sensor 110 and second sensor 120 are capable of identifying an object
without additional
equipment such as a guideway map or location and speed information. The
ability to operate
without additional equipment decreases operating costs for first sensor 110
and second sensor
120 and reduces points of failure for fusion sensor arrangement 100.
Data fusion center 130 includes a non-transitory computer readable medium
configured to
store information received from first sensor 110 and second sensor 120. Data
fusion center
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130 also includes a processor configured to execute instructions for
identifying objects
detected by first sensor 110 or second sensor 120. The processor of data
fusion center 130 is
further configured to execute instructions for resolving conflicts between
first sensor 110 and
second sensor 120.
Data fusion center 130 is configured to receive information from first sensor
110 and second
sensor 120 and confirm detection of an object and whether the detected object
contains
identifying information. Data fusion center 130 is further configured to
determine a distance
from the fusion sensor arrangement 100 to the detected object, a relative
speed of the object,
a heading angle of the object and an elevation angle of the object.
Based on these determinations, data fusion center 130 is capable of tracking
the detected
object as the guideway mounted vehicle travels along the guideway to determine
whether the
object is on the guideway or on the wayside of the guideway. Tracking the
object means that
a location and relative speed of the object are regularly determined in a time
domain. In
some embodiments, the location and relative speed of the object are determined
periodically,
e.g., having an interval ranging from 1 second to 15 minutes. In some
embodiments, the
location and relative speed of the object are determined continuously.
Data fusion center 130 is also capable of comparing information from first
sensor 110 with
information from second sensor 120 and resolving any conflicts between the
first sensor and
the second senor. Data fusion center 130 is configured to perform plausibility
checks to help
determine whether a sensor is detecting an actual object. In some embodiments,
the
plausibility check is performed by tracking a location of the object. In some
embodiments, a
relative change in the location of the object with respect to time which
exceeds a threshold
value results in a determination that the detected object is implausible. When
an implausible
determination is made, data fusion center 130 considers information received
from the other
sensor to be more reliable. In some embodiments, data fusion center 130
initiates a status
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check of a sensor which provides implausible information. In some embodiments,
data
fusion center 130 initiates a status check of a sensor which provides
implausible information
multiple times within a predetermined time period.
In some embodiments, when one sensor detects an object but the other sensor
does not, data
fusion center 130 is configured to determine that the object is present. In
some embodiments,
data fusion center 130 initiates a status check of the sensor which did not
identify the object.
In some embodiments, data fusion center 130 initiates a status check of the
sensor which did
not identify the object based on a type of object detected. For example, a
thermal sensor is
not expected to identify RFID transponder; therefore, the data fusion center
130 would not
initiate a status check of the thermal sensor, in some embodiments.
In some embodiments, when one sensor detects a first type of object and the
other sensor
detects a second type of object different from the first type of object data
fusion center 130
selects the object type based on a set of priority rules. In some embodiments,
the priority
rules give a higher priority to a certain type of sensor, e.g., a RADAR sensor
over a laser
sensor. In some embodiments, priority between sensor types is determined based
on a
distance between fusion sensor arrangement 100 and the detected object. For
example,
priority is given to the RADAR sensor if the distance between fusion sensor
arrangement 100
and the detected object is greater than 100 meters (m) and priority is given
to the laser sensor
if the distance is less than 100 m or less.
Data fusion center 130 is a vehicle system. In some embodiments, data fusion
center 130 has
a safety integrity level 4 (SIL 4). In some embodiments, SIL 4 is based on
International
Electrotechnical Commission's (IEC) standard IEC 61508, in at least one
embodiment. SIL
level 4 means the probability of failure per hour ranges from 10-8 to 10-9.
Fusion sensor arrangement 100 is able to achieve a low rate of failure through
the use of two
separate sensors configured to detect objects using diverse detection
techniques. In some
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embodiments, each sensor is designed to have a failure rate of about 3.8 x 10-
5 failures per
hour, meaning a single failure every three years. A probability of two sensors
having a
failure at a same time is about T x 3.6 x10-1 failures per hour. where T is
an expected time
interval between detected objects. In some embodiments, T ranges from about 2
minutes to
about 40 minutes. In some embodiments, if fusion sensor arrangement 100 fails
to detect an
object within 2T, the fusion sensor arrangement is determined to be faulty and
is timed out.
The above description is based on the use of two sensors, first sensor 110 and
second sensor
120, for the sake of clarity. One of ordinary skill in the art would recognize
that additional
sensors are able to be incorporated into fusion sensor arrangement 100 without
departing
from the scope of this description. In some embodiments, redundant sensors
which are a
same sensor type as first sensor 110 or second sensor 120 are included in
fusion sensor
arrangement 100. In some embodiments, additional sensors of different sensor
type from
first sensor 110 and second sensor 120 are included in fusion sensor
arrangement 100.
Data fusion center 130 is also capable of identifying location determining
information such as
the unique identification information for the object. Data fusion center 130
is able to provide
information regarding whether the guideway mounted vehicle is aligned with an
object, e.g.,
for positioning doors for passenger vehicles with platform openings.
Figure 2A is a high level diagram of a guideway mounted vehicle 202 including
fusion sensor
arrangements 210a and 210b in accordance with one or more embodiments.
Guideway
mounted vehicle 202 is positioned on a guideway 204. Guideway mounted vehicle
202 has a
first end 206 and a second end 208. A first fusion sensor arrangement 210a is
located at first
end 206 and a second fusion sensor arrangement 210b is located at second end
208. First
fusion sensor arrangement 210a has a first field of detection 220a extending
from first end
206. First field of detection 220a extends in an angular range in the
horizontal direction and
in the vertical direction. Second fusion sensor arrangement 210b has a second
field of
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detection 220b extending from second end 208. Second field of detection 220b
extends in an
angular range in the horizontal direction and in the vertical direction.
Guideway mounted vehicle 202 is configured to traverse along guideway 204. In
some
embodiments, guideway mounted vehicle 202 is a passenger train, a cargo train,
a tram, a
monorail, or another suitable vehicle. In some embodiments, guideway mounted
vehicle 202
is configured for bi-directional travel along guideway 204.
Guideway 204 is configured to provide a direction and heading of travel for
guideway
mounted vehicle 202. In some embodiments, guideway 204 includes two spaced
rails. In
some embodiments, guideway 204 includes a monorail. In some embodiments,
guideway
204 is along a ground. In some embodiments, guideway 204 is elevated above the
ground.
First end 206 and second end 208 are a corresponding leading end and trailing
end of
guideway mounted vehicle 202 depending on a direction of travel of the
guideway mounted
vehicle 202. By attaching fusion sensor arrangements 210a and 210b at both
first end 206
and second end 208, either first detection field 220a or second detection
field 220b extend in
front of guideway mounted vehicle 202 in the direction of travel.
First fusion sensor arrangement 210a and second fusion sensor arrangement 210b
are similar
to fusion sensor arrangement 100 (Figure 1). In some embodiments, at least one
of first
fusion sensor arrangement 210a or second fusion sensor arrangement 210b is
integrated with
a VOBC on guideway mounted vehicle 202. In some embodiments, both first fusion
sensor
arrangement 210a and second fusion sensor arrangement 210b are separate from
the VOBC.
In some embodiments, at least one of first fusion sensor arrangement 210a or
second fusion
sensor arrangement 210b is detachable from guideway mounted vehicle to
facilitate repair
and replacement of the fusion sensor arrangement.
Figure 2B is a high level diagram of a guideway mounted vehicle 200' including
fusion
sensor arrangements 250a and 250b in accordance with one or more embodiments.
CA 02977730 2017-08-24
Figure 2B includes only a single end of guideway mounted vehicle 200' for
simplicity.
Guideway mounted vehicle 200' includes a first fusion sensor arrangement 250a
and a
second fusion sensor arrangement 250b. First fusion sensor arrangement 250a
has a first
field of detection 260a. Second fusion sensor arrangement 250b has a second
field of
detection 260b. First field of detection 260a overlaps with second field of
detection 260b.
First fusion sensor arrangement 250a and second fusion sensor arrangement 250b
are similar
to fusion sensor arrangement 100 (Figure 1). In some embodiments, first fusion
sensor
arrangement 250a has a same type of sensors as second fusion sensor
arrangement 250b. In
some embodiments, first fusion sensor arrangement 250a has at least one
different type of
sensor from second fusion sensor arrangement 250b. By using multiple fusion
sensor
arrangements 250a and 250b, a position of an objection is able to be
triangulated by
measuring a distance between each fusion sensor arrangement and the object.
Figure 3 is a flow chart of a method 300 of controlling a guideway mounted
vehicle using a
fusion sensor arrangement in accordance with one or more embodiments. The
fusion sensor
arrangement in method 300 is used in combination with a VOBC. In some
embodiments, the
fusion sensor arrangement is integrated with the VOBC. In some embodiments,
the fusion
sensor arrangement is separable from the VOBC. In optional operation 302, the
VOBC
communication with a centralized or de-centralized control system is lost. In
some
embodiments, communication is lost due to a device failure. In some
embodiments,
communication is lost due to signal degradation or corruption. In some
embodiments,
communication is lost due to blockage of the signal by a terrain. In some
embodiments,
operation 302 is omitted. Operation 302 is omitted in some embodiments where
the fusion
sensor arrangement is operated simultaneously with instructions received from
centralized or
de-centralized communication system.
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In some embodiments, information received through the fusion sensor
arrangement is
transmitted via the VOBC to the centralized or de-centralized communication
system. In
some embodiments, information received through the fusion sensor arrangement
is provided
to a remote driver to facilitate control of the guideway mounted vehicle by
the remote driver.
In some embodiments, the remote driver is able to receive images captured by
the fusion
sensor arrangement. In some embodiments, the remote driver is able to receive
numerical
information captured by the fusion sensor arrangement. In some embodiments,
the VOBC is
configured to receive instructions from the remote driver and automatically
control a braking
and acceleration system of the guideway mounted vehicle.
In optional operation 304, a maximum speed is set by the VOBC. The maximum
speed is set
so that the guideway mounted vehicle is capable of braking to a stop within a
line of sight
distance of the fusion sensor arrangement. In situations where the VOBC relies
solely on the
fusion sensor arrangement for the detection of objects along the guideway or
the wayside of
the guideway, such as during loss of communication with the centralized or de-
centralized
control system, the VOBC is able to determine a limit of movement authority
(LMA) to the
extent that the fusion sensor arrangement is capable of detecting objects. The
VOBC is
capable of automatically controlling the braking and acceleration system of
the guideway
mounted vehicle in order to control the speed of the guideway mounted vehicle
to be at or
below the maximum speed. In some embodiments, operation 304 is omitted if the
VOBC is
able to communicate with the centralized or de-centralized control system and
is able to
receive LMA instructions through the control system. The centralized and de-
centralized
control systems have information regarding the presence of objects along the
guideway
within an area of control of the control system. If the area of control
extends beyond a line of
sight of the fusion sensor arrangement, the VOBC is able to set a speed
greater than the
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maximum speed in order for the guideway mounted vehicle to more efficiently
travel along
the guideway.
Data is received from at least two sensors in operation 306. The at least two
sensors are
similar to first sensor 110 or second sensor 120 (Figure 1). In some
embodiments, data is
received by more than two sensors. At least one sensor of the at least two
sensors is capable
of a different type of detection from the at least another sensor of the at
least two sensors.
For example, one sensor is an optical sensor and the other sensor is an RFID
reader. In some
embodiments, at least one sensor of the at least two sensors is capable of a
same type of
detection as at least another sensor of the at least two sensors. For example,
a redundant
optical sensor is included in case a primary optical sensor fails, in some
embodiments.
A field of detection of each sensor of the at least two sensors overlaps with
each other. The
field of detection includes an angular range in the horizontal direction and
an angular range in
the vertical direction. The angular range in the horizontal directions enables
detection of
objects along the guideway and the wayside of the guideway. The angular range
in the
vertical direction enables detection of objects which present a vertical
blockage. The angular
range in the vertical direction also enables detection of objects on a
guideway above or below
the guideway on which the guideway mounted vehicle is located.
In operation 308, the received data is fused together. The received data is
fused together
using a data fusion center, e.g., data fusion center 130 (Figure 1). The data
is fused together
to provide a more comprehensive detection of objects along the guideway and
the wayside of
the guideway in comparison with data representing a single type of detection.
In some
embodiments, fusing the data includes confirming detection of an object and
whether the
detected object contains identifying information. In some embodiments, fusing
the data
includes determining a relative position, speed or heading of the detected
object. In some
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embodiments, fusing the data together includes resolving conflicts between the
received data.
In some embodiments, fusing the data includes performing a plausibility check.
Resolving conflicts between the received data results is performed when data
received from
one sensor does not substantially match with data received by the other
sensor. In some
embodiments, a predetermine tolerance threshold is established for determining
whether a
conflict exists within the received data. The predetermined tolerance
threshold helps to
account for variations in the data which result from the difference in the
detection type of the
sensors. In some embodiments, a conflict is identified if an object is
detected by one sensor
but the object is not detected by the other sensor. In some embodiments, a
status check of the
sensor which did not identify the object is initiated. In some embodiments, a
status check of
the sensor which did not identify the object is initiated based on a type of
object detected.
For example, a thermal sensor is not expected to identify RFID transponder;
therefore, a
status check of the thermal sensor is not initiated, in some embodiments.
In some embodiments, conflicts between the received data related to the
detected object are
resolved by averaging the data received from the sensors. In some embodiments,
resolving
the conflict is based on a set of priority rules. In some embodiments, the
priority rules give a
higher priority to a certain type of sensor, e.g., a RFID reader over an
optical sensor. In some
embodiments, priority between sensor types is determined based on a distance
between the
fusion sensor arrangement and the detected object. For example, priority is
given to the
RADAR sensor if the distance between the fusion sensor arrangement and the
detected object
is greater than 100 meters (m) and priority is given to the optical sensor if
the distance is 100
m or less.
Performing the plausibility check includes evaluating a relative change in the
location of the
object with respect to time. If the relative change in location exceeds a
threshold value the
object is determined to be implausible. When an implausible determination is
made with
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respect to one sensor, data received from the other sensor is determined to be
more reliable.
In some embodiments, a status check of a sensor which provides implausible
information is
initiated. In some embodiments, a status check of a sensor which provides
implausible
information multiple times within a predetermined time period is initiated.
In optional operation 309, a status check of at least one sensor is initiated.
In some
embodiments, the status check is initiated as a result of a conflict between
the received data.
In some embodiments, the status check is initiated as a result of receiving
implausible data.
In some embodiments, the status check is initiated periodically to determine a
health of a
sensor prior to a conflict or receipt of implausible data. In some
embodiments, periodic
status checks are suspended while communication with the centralized or de-
centralized
control system is lost unless a conflict or implausible data is received.
In some embodiments, the VOBC receives the fused data and operates in
conjunction with
the centralized or de-centralized control to operate the guideway mounted
vehicle. The
VOBC receives LMA instructions from the centralized or de-centralized control.
The LMA
instructions are based on data collected with respect to objects, including
other guideway
mounted vehicles, within an area of control for the centralized or de-
centralized control
system. Based on the received LMA instructions, the VOBC will control the
acceleration and
braking system of the guideway mounted vehicle in order to move the guideway
mounted
vehicle along the guideway.
The VOBC receives the fused data from the fusion sensor arrangement and
determines a
speed and a location of the guideway mounted vehicle based on the detected
objects. For
example, a sign or post containing a unique identification is usable to
determine a location of
the guideway mounted vehicle. In some embodiments, the VOBC includes a
guideway
database which includes a map of the guideway and a location of stationary
objects
associated with unique identification information. In some embodiments, the
VOBC is
CA 02977730 2017-08-24
configured to update the guideway database to include movable objects based on
information
received from the centralized or de-centralized control system. By comparing
the fused data
with respect to an identifiable object with the guideway database, the VOBC is
able to
determine the location of the guideway mounted vehicle. In some embodiments,
the VOBC
determines a speed of the guideway mounted vehicle based on a change in
location of an
object detected in the fused data. The VOBC transmits the determined location
and speed of
the guideway mounted vehicle to the centralized or de-centralized control
system.
In some embodiments, if communication with the centralized or de-centralized
control
system is lost, the VOBC performs autonomous operations 310. In operation 312,
the VOBC
identifies a detected object based on the fused data. In some embodiments, the
VOBC
identifies the detected object by comparing the fused data with information
stored in the
guideway database.
In some embodiments, the VOBC uses the identified object to determine a
location of the
guideway mounted vehicle in operation 314. In some embodiments, the VOBC
determines
the location of the guideway mounted vehicle based on unique identification
information
associated with the detected object. In some embodiments, the VOBC compares
the unique
identification information with the guideway database to determine the
location of the
guideway mounted vehicle.
The identified object is tracked in operation 316. Tracking the object means
that a location
and relative speed of the object are regularly determined in a time domain. In
some
embodiments, the object is tracked to determine whether the object will be on
the guideway
at a same location as the guideway mounted vehicle. In some embodiments, the
object is
tracked in order to provide location information for a non-communicating
guideway mounted
vehicle. In some embodiments, the location and relative speed of the object
are determined
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periodically, e.g., having an interval ranging from 1 second to 15 minutes. In
some
embodiments, the location and relative speed of the object are determined
continuously.
In operation 318, the VOBC provides instructions for the guideway mounted
vehicle to
proceed to a stopping location. In some embodiments, the stopping location
includes a
destination of the guideway mounted vehicle, a switch, a detected object on
the guideway,
coupling/de-coupling location, a protection area of a non-communicating
guideway mounted
vehicle or another suitable stopping location. A non-communicating guideway
mounted
vehicle is a vehicle which is traveling along the guideway which is under only
manual
operation, is experiencing a communication failure, lacks communication
equipment or other
similar vehicles. The VOBC autonomously generates instructions including LMA
instructions. The LMA instructions are executed based on signals transmitted
to the
acceleration and braking system. In some embodiments, the LMA instructions are
based on
the location of the guideway mounted vehicle determined in operation 314 and
the guideway
database.
In some embodiments where the stopping location is a destination of the
guideway mounted
vehicle, the LMA instructions generated by the VOBC enable the guideway
mounted vehicle
to travel to a platform, station, depot or other location where the guideway
mounted vehicle is
intended to stop. In some embodiments, the VOBC controls the acceleration and
braking
system to maintain the guideway mounted vehicle at the destination until
communication is
re-established with the centralized or de-centralized control system or until
a driver arrives to
manually operate the guideway mounted vehicle.
In some embodiments where the stopping location is a switch, the LMA
instructions
generated by the VOBC cause the guideway mounted vehicle to stop at a heel of
the switch if
the switch is in a disturbed state. In some embodiments, the LMA instructions
cause the
guideway mounted vehicle to stop if the fused data fails to identify a state
of the switch. In
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CA 02977730 2017-08-24
some embodiments, the LMA instructions cause the guideway mounted vehicle to
stop if the
fused data indicates a conflict regarding a state of the switch. In some
embodiments, the
LMA instructions cause the guideway mounted vehicle to stop if the most recent
information
received from the centralized or de-centralized control system indicated the
switch is reserved
for another guideway mounted vehicle.
In some embodiments where the stopping location is an object detected on the
guideway, the
LMA instructions generated by the VOBC cause the guideway mounted vehicle to
stop a
predetermined distance prior to reaching the detected object. In some
embodiments, the
object is a person, a disturbed switch, debris or another object along the
guideway. In some
embodiments, the VOBC uses the fused data to predict whether a detected object
will be on
the guideway when the guideway mounted vehicle reaches the location of the
object. In
some embodiments, the LMA instructions cause the guideway mounted vehicle to
stop the
predetermined distance prior to the object if the object is predicted to be on
the guideway at
the time the guideway mounted vehicle reaches the location of the object.
In some embodiments where the stopping location is a coupling/uncoupling
location, the
LMA instructions generated by the VOBC cause the guideway mounted vehicle to
stop at the
coupling/de-coupling location. The fused data is used to determine a distance
between the
guideway mounted vehicle and the other vehicle to be coupled/de-coupled. The
VOBC is
used to control the speed of the guideway mounted vehicle such that the
coupling/de-
coupling is achieved without undue force on a coupling joint of the guideway
mounted
vehicle. In some embodiments, the VOBC brings the guideway mounted vehicle to
a stop
while a separation distance between the two guideway mounted vehicles is less
than a
predetermined distance.
In some embodiments, where the stopping location is the protection area of a
non-
communicating guideway mounted vehicle, the LMA instructions generated by the
VOBC
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CA 02977730 2017-08-24
stop the guideway mounted vehicle prior to entering the protection area. The
protection area
is a zone around the non-communicating guideway mounted vehicle to enable
movement of
the non-communicating guideway mounted vehicle with minimal interference with
other
guideway mounted vehicles. The protection area is defined by the centralized
or de-
centralized control system. In some embodiments, the LMA instructions cause
the guideway
mounted vehicle to stop prior to entering the protection area based on the
most recent
received information from the centralized or de-centralized control system.
One of ordinary skill in the art would recognize that additional stopping
location and control
processes are within the scope of this description.
In some embodiments, the VOBC continues movement of the guideway mounted
vehicle
along the guideway, in operation 320. The continued movement is based on a
lack of a
stopping location. In some embodiments, the VOBC controls reduction of the
speed of the
guideway mounted vehicle if a switch is traversed. The reduced speed is a
switch traversal
speed. The switch traversal speed is less than the maximum speed from
operation 304. In
some embodiments, operation 320 is continued until a stopping location is
reached,
communication is re-established with the centralized or de-centralized control
system or a
manual operator arrives to control the guideway mounted vehicle.
In some embodiments, following fusing of the received data in operation 308,
LMA
instructions are generated using remote driver operations 330. In operation
340, the fused
data is transmitted to the remote driver, i.e., an operator who is not on-
board the guideway
mounted vehicle. In some embodiments, fused data is transmitted using the
centralized or de-
centralized control system. In some embodiments, the fused data is transmitted
using a back-
up communication system such as an inductive loop communication system, a
radio
communication system, a microwave communication system, or another suitable
communication system. In some embodiments, the fused data is transmitted as an
image. In
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CA 02977730 2017-08-24
some embodiments, the fused data is transmitted as alpha-numerical
information. In some
embodiments, the fused data is transmitted in an encrypted format.
In operation 342, the VOBC receives instructions from the remote driver. In
some
embodiments, the VOBC receives instructions along a same communication system
used to
transmit the fused data. In some embodiments, the VOBC receives the
instructions along a
different communication system from that used to transmit the fused data. In
some
embodiments, the instructions include LMA instructions, speed instructions,
instructions to
traverse a switch, or other suitable instructions.
The VOBC implements permissible instructions in operation 344. In some
embodiments,
permissible instructions are instructions which do not conflict with the
maximum speed set in
operation 304, a switch traversal speed, traversing a disturbed switch,
traversing a portion of
the guideway where an object is detected or other suitable conflicts. In some
embodiments, if
the speed instructions from the remote driver exceed the maximum speed, the
VOBC controls
the guideway mounted vehicle to travel at the maximum speed. In some
embodiments, if the
speed instructions from the remote driver exceed the switch traversal speed,
the VOBC
controls the guideway mounted vehicle to travel at the switch traversal speed.
In some
embodiments, the VOBC controls the guideway mounted vehicle to traverse a
switch which
the fused data indicates as disturbed (or a conflict exists regarding the
state of the switch) if
the VOBC receives LMA instructions from the remote driver to traverse the
switch. In some
embodiments, the VOBC controls the guideway mounted vehicle to stop if the LMA
instructions from the remote driver include traversing a portion of the
guideway which
includes a detected object.
One of ordinary skill in the art would recognize that an order of operations
of method 300 is
adjustable. One of ordinary skill in the art would also recognize that
additional operations are
includable in method 300, and that operations are able to be omitted form
operation 300.
CA 02977730 2017-08-24
Figure 4 is a functional flow chart of a method 400 of determining a status of
a fusion sensor
arrangement in accordance with one or more embodiments. In some embodiments,
method
400 is performed if operation 309 of method 300 (Figure 3) is performed. In
some
embodiments, a VOBC causes method 400 to be executed periodically. In some
embodiments, a data fusion center, e.g., data fusion center 130 (Figure 1),
causes method 400
to be executed upon determination of implausible data or upon receipt of
conflicting data.
In operation 402, the VOBC determines a speed of the guideway mounted vehicle.
In some
embodiments, the VOBC determines the speed of the guideway based on
information
received from the centralized or de-centralized control system, information
received from a
data fusion center, e.g., data fusion center 130 (Figure 1), measures taken
from the guideway
mounted vehicle (such as wheel revolutions per minute), or other suitable
information
sources. In some embodiments, the VOBC transmits the speed of the guideway
mounted
vehicle to the centralized or de-centralized control system.
In operation 404, the VOBC determines a position of the guideway mounted
vehicle. In
some embodiments, the VOBC determines the position of the guideway based on
information
received from the centralized or de-centralized control system, information
received from a
data fusion center, e.g., data fusion center 130 (Figure 1), wayside
transponders, or other
suitable information sources. In some embodiments, the VOBC transmits the
position of the
guideway mounted vehicle to the centralized or de-centralized control system.
In operation 406. the VOBC determines whether the speed information is lost.
In some
embodiments, the speed information is lost due to failure of a communication
system, failure
of the data fusion center, an error within the VOBC or failure of another
system.
In operation 408, the VOBC determines whether the position information is
lost. In some
embodiments, the speed information is lost due to failure of a communication
system, failure
of the data fusion center, an error within the VOBC or failure of another
system.
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CA 02977730 2017-08-24
If both of the speed information and the position information are still
available, the VOBC
determines if communication has timed out with the centralized or de-
centralized control
system, in operation 410. In some embodiments, the VOBC determines if
communication
has timed out by transmitting a test signal and determining whether a return
signal is
received. In some embodiments, the VOBC determines if communication has timed
out base
on an elapsed time since a last received communication. In some embodiments.
the VOBC
determines whether communication has timed out based whether an update to the
guideway
database was received from a control system 460.
If communication has not timed out, the VOBC determines whether a sensor of
the fusion
sensor arrangement did not detect a train that was expected to be detected in
operation 412.
The VOBC receives sensor information from data fusion center 450 and guideway
database
information from control system 460. Based on the guideway database
information, the
VOBC determines whether another guideway mounted vehicle is located at a
position where
the sensor of the fusion sensor arrangement should detect the other guideway
mounted
vehicle. Using the sensor information from data fusion center 450, the VOBC
determines
whether the other guideway mounted vehicle was detected. If a guideway mounted
vehicle
was available for detection and the sensor did not detect the guideway mounted
vehicle,
method 400 continues to operation 414.
In operation 414, the sensor of the fusion sensor arrangement is determined to
be faulty. The
VOBC provides instructions to data fusion center 450 to no longer rely on the
faulty sensor.
In some embodiments which include only two sensors in the fusion sensor
arrangement, the
VOBC ceases to rely on information provided by the fusion sensor arrangement.
In some
embodiments, the VOBC transmits a signal indicating a reason for determining
the sensor as
being faulty. In operation 414, the VOBC transmits a signal indicating the
sensor failed to
detect a guideway mounted vehicle, in some embodiments.
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CA 02977730 2017-08-24
If no guideway mounted vehicle was available for detection or the sensor did
detect a
guideway mounted vehicle in operation 412, method 400 continues with operation
416. In
operation 416, the VOBC determines whether the sensor detected a non-existing
guideway
mounted vehicle. Based on the guideway database information received from
control
system 460 and sensor information from data fusion center 450, the VOBC
determines
whether the sensor detected a guideway mounted vehicle where no guideway
mounted
vehicle is located. If a guideway mounted vehicle was detected, but the
guideway dataset
information indicates no guideway mounted vehicle was present, method 400
continues with
operation 418.
In operation 418, the sensor of the fusion sensor arrangement is determined to
be faulty. The
VOBC provides instructions to data fusion center 450 to no longer rely on the
faulty sensor.
In some embodiments which include only two sensors in the fusion sensor
arrangement, the
VOBC ceases to rely on information provided by the fusion sensor arrangement.
In some
embodiments, the VOBC transmits a signal indicating a reason for determining
the sensor as
being faulty. In operation 418, the VOBC transmits a signal indicating the
sensor detected a
non-existent guideway mounted vehicle, in some embodiments.
If no guideway mounted vehicle was available for detection and the sensor did
not detect a
guideway mounted vehicle in operation 416, method 400 continues with operation
420. In
operation 420. the VOBC determines whether the sensor detected a known wayside
mounted
object. Based on the guideway database information received from control
system 460 and
sensor information from data fusion center 450, the VOBC determines whether
the sensor
detected a wayside mounted object where a known wayside mounted object is
located. If a
known wayside mounted object was not detected, method 400 continues with
operation 422.
In operation 422, the sensor of the fusion sensor arrangement is determined to
be faulty. The
VOBC provides instructions to data fusion center 450 to no longer rely on the
faulty sensor.
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CA 02977730 2017-08-24
In some embodiments which include only two sensors in the fusion sensor
arrangement, the
VOBC ceases to rely on information provided by the fusion sensor arrangement.
In some
embodiments, the VOBC transmits a signal indicating a reason for determining
the sensor as
being faulty. In operation 422, the VOBC transmits a signal indicating the
sensor failed to
detect a known wayside mounted object, in some embodiments.
If the known wayside mounted object was detected in operation 420, method 400
continues
with operation 424. In operation 424, the VOBC determines a location of the
wayside
mounted vehicle and transmits the determined location to control system 460 to
update a
location of the wayside mounted vehicle in the control system. In some
embodiments,
operation 424 is performed following operation 404. In some embodiments,
operation 424 is
performed every time a new location of the guideway mounted vehicle is
determined.
In operation 426, the VOBC determines whether the guideway mounted vehicle is
involved
in a coupling/de-coupling process. The VOBC determines whether the guideway
mounted
vehicle is involved in the coupling/de-coupling process based on the sensor
information from
fusion data center 450 and the guideway database information from control
system 460. The
VOBC determines whether another guideway mounted vehicle is located within a
coupling
proximity to the guideway mounted vehicle. If the VOBC determines that the
guideway
mounted vehicle is involved in a coupling/de-coupling process, method 400
continues with
operation 428.
In operation 428, the VOBC determine a precise distance between the guideway
mounted
vehicle and the other guideway mounted vehicle. The VOBC uses the senor
information and
the guideway database information to determine the precise distance. In some
embodiments,
the VOBC sends instructions to data fusion center 450 to increase resolution
of the sensor
information. In some embodiments, the VOBC sends instructions to the
acceleration and
braking system to reduce the speed of the guideway mounted vehicle so that the
location of
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CA 02977730 2017-08-24
the guideway mounted vehicle has a decreased rate of change. In some
embodiment, the
VOBC request more frequent update of the guideway database information from
control
system 460 to better determine a relative position of the other guideway
mounted vehicle.
If the VOBC determines the guideway mounted vehicle is not involved in a
coupling/de-
coupling process, method 400 continues with operation 430. In operation 430,
the VOBC
continues to operate the guideway mounted vehicle in coordination with control
system 460.
In some embodiments, the VOBC uses the sensor information from data fusion
center 450 in
conjunction with information from control system 460. In some embodiments, the
VOBC
does not rely on the sensor information from data fusion center 450 in
operation 430.
Returning to operations 406, 408 and 410, if the speed of the guideway mounted
vehicle or
the location of the guideway mounted vehicle is lost, or if communication with
control
system 460 has timed out, method 400 continues with operation 440. In
operation 440, the
VOBC relies on a fallback operation supervision to operate the guideway
mounted vehicle.
In some embodiments, the VOBC relies on sensor information from data fusion
center 450 to
operate the guideway mounted vehicle. In some embodiments, the VOBC performs
in a
manner similar to method 300 (Figure 3) to operate the guideway mounted
vehicle.
In operation 442, the VOBC determines whether communication with control
system 460 is
re-established. If communication with control system 460 is re-established,
method 400
continues with operation 444. If communication with control system 460 is no
re-
established, method 400 returns to operation 440.
In operation 444, the VOBC determines whether the location of the guideway
mounted
vehicle is re-established. If the location of the guideway mounted vehicle is
re-established,
method 400 continues with operation 430. If the location of the guideway
mounted vehicle is
not re-established, method 400 returns to operation 440.
CA 02977730 2017-08-24
Figure 5 is a block diagram of a VOBC 500 for using a fusion sensor
arrangement in
accordance with one or more embodiments. VOBC 500 includes a hardware
processor 502
and a non-transitory, computer readable storage medium 504 encoded with, i.e.,
storing, the
computer program code 506, i.e., a set of executable instructions. Computer
readable storage
medium 504 is also encoded with instructions 507 for interfacing with
manufacturing
machines for producing the memory array. The processor 502 is electrically
coupled to the
computer readable storage medium 504 via a bus 508. The processor 502 is also
electrically
coupled to an I/O interface 510 by bus 508. A network interface 512 is also
electrically
connected to the processor 502 via bus 508. Network interface 512 is connected
to a network
514, so that processor 502 and computer readable storage medium 504 are
capable of
connecting to external elements via network 514. VOBC 500 further includes
data fusion
center 516. The processor 502 is connected to data fusion center 516 via bus
508. The
processor 502 is configured to execute the computer program code 506 encoded
in the
computer readable storage medium 504 in order to cause system 500 to be usable
for
performing a portion or all of the operations as described in method 300 or
method 400.
In some embodiments, the processor 502 is a central processing unit (CPU), a
multi-
processor, a distributed processing system, an application specific integrated
circuit (ASIC),
and/or a suitable processing unit.
In some embodiments, the computer readable storage medium 504 is an
electronic, magnetic,
optical, electromagnetic, infrared, and/or a semiconductor system (or
apparatus or
device). For example, the computer readable storage medium 504 includes a
semiconductor
or solid-state memory, a magnetic tape, a removable computer diskette, a
random access
memory (RAM), a read-only memory (ROM), a rigid magnetic disk, and/or an
optical
disk. In some embodiments using optical disks, the computer readable storage
medium 504
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CA 02977730 2017-08-24
includes a compact disk-read only memory (CD-ROM), a compact disk-read/write
(CD-
R/W), and/or a digital video disc (DVD).
In some embodiments, the storage medium 504 stores the computer program code
506
configured to cause system 500 to perform method 300 or method 400. In some
embodiments, the storage medium 504 also stores information needed for
performing a
method 300 or 400 as well as information generated during performing the
method 300 or
400, such as a sensor information parameter 520, a guideway database parameter
522, a
vehicle location parameter 524, a vehicle speed parameter 526 and/or a set of
executable
instructions to perform the operation of method 300 or 400.
In some embodiments, the storage medium 504 stores instructions 507 for
interfacing with
manufacturing machines. The instructions 507 enable processor 502 to generate
manufacturing instructions readable by the manufacturing machines to
effectively implement
method 400 during a manufacturing process.
VOBC 500 includes I/O interface 510. I/O interface 510 is coupled to external
circuitry. In
some embodiments, I/O interface 510 includes a keyboard, keypad, mouse,
trackball,
trackpad, and/or cursor direction keys for communicating information and
commands to
processor 502.
VOBC 500 also includes network interface 512 coupled to the processor 502.
Network
interface 512 allows VOBC 500 to communicate with network 514, to which one or
more
other computer systems are connected. Network interface 512 includes wireless
network
interfaces such as BLUETOOTH, WIFI, WIMAX, GPRS, or WCDMA; or wired network
interface such as ETHERNET, USB, or IEEE-1394. In some embodiments, method 300
or
400 is implemented in two or more VOBCs 500, and information such as memory
type,
memory array layout, I/0 voltage, I/O pin location and charge pump are
exchanged between
different VOBCs 500 via network 514.
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CA 02977730 2017-08-24
VOBC further includes data fusion center 516. Data fusion center 516 is
similar to data
fusion center 130 (Figure 1). In the embodiment of VOBC 500, data fusion
center 516 is
integrated with VOBC 500. In some embodiments, the data fusion center is
separate from
VOBC 500 and connects to the VOBC through I/0 interface 510 or network
interface 512.
VOBC 500 is configured to receive sensor information related to a fusion
sensor
arrangement, e.g., fusion sensor arrangement 100 (Figure 1), through data
fusion center 516.
The information is stored in computer readable medium 504 as sensor
information
parameter 520. VOBC 500 is configured to receive information related to the
guideway
database through I/O interface 510 or network interface 512. The information
is stored in
computer readable medium 504 as guideway database parameter 522. VOBC 500 is
configured to receive information related to vehicle location through I/0
interface 510,
network interface 512 or data fusion center 516. The information is stored in
computer
readable medium 504 as vehicle location parameter 524. VOBC 500 is configured
to receive
information related to vehicle speed through I/0 interface 510, network
interface 512 or data
fusion center 516. The information is stored in computer readable medium 504
as vehicle
speed parameter 526.
During operation, processor 502 executes a set of instructions to determine
the location and
speed of the guideway mounted vehicle, which are used to update vehicle
location parameter
524 and vehicle speed parameter 526. Processor 502 is further configured to
receive LMA
instructions and speed instructions from a centralized or de-centralized
control system, e.g.,
control system 460. Processor 502 determines whether the received instructions
are in
conflict with the sensor information. Processor 502 is configured to generate
instructions for
controlling an acceleration and braking system of the guideway mounted vehicle
to control
travel along the guideway.
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CA 02977730 2017-08-24
Figure 6 is a block diagram of a system 600 for determining a position of a
guideway
mounted vehicle such as guideway mounted vehicle 202 (Figure 2), in accordance
with one
or more embodiments.
System 600 comprises a speed detector 601, a marker sensor 603, a controller
605, and an
Attitude and I Icadina Reference System (AI IRS) 607.
Speed detector 601 is configured to generate speed data associated with a
movement of the
vehicle. In some embodiments, speed detector 601 is a tachometer configured to
detect a
rotational speed of a wheel of the guideway mounted vehicle. In some
embodiments, speed
detector 601 is a global positioning system (GPS) unit or receiver capable of
providing speed
related information. In some embodiments, speed detector 601 is some other
suitable
detector, sensor or system, configured to provide speed related data
associated with a
movement of the vehicle.
Marker sensor 603 is configured to generate marker data based on a detection
of an object
along a wayside of a guideway along which the vehicle is configured to move.
In some
embodiments, the object is a marker. A marker is, for example, a transponder
tag detectable
by a reader, a crossover/loop boundary, a static object such as a sign or a
shape that has a
location that is known to the VOBC, an object that is detectable by way of a
fusion sensor
such as fusion sensor arrangement 100 (Figure 1), a distinct or sharp change
in one or more
guideway properties (e.g. direction, curvature, or other identifiable
property) which can be
accurately associated with a specific location, or other suitable detectable
feature or object
usable to determine a geographic location of a vehicle.
In some embodiments, the marker sensor 603 comprises one or more of an RFID
reader, an
RF transponder, a fusion sensor arrangement such as fusion sensor arrangement
100 (Figure
1), or other suitable sensor usable to detect a change in a guideway property
such as direction,
curvature, or other recognizable property associated with the guideway. In
some
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CA 02977730 2017-08-24
embodiments, the marker data comprises data usable by the controller 605 to
determine the
geographic location of the vehicle in terms of a geographic coordinate system
(e.g., latitude,
longitude, and/or altitude).
Controller 605 is coupled with the speed detector 601 and the marker sensor
603. Controller
605 is configured to calculate a distance the vehicle moved based on the speed
data and the
marker data. Controller 605 is also configured to generate location
information based on the
distance the vehicle moved and the marker data. Controller 605 is further
configured to
generate an indication that the vehicle is stationary based on the speed data.
In some
embodiments, controller 605 autonomously determines vehicle location, speed
and direction
of movement along the guideway. In some embodiments, controller 605 is a VOBC
such as
VOBC 500 (Figure 5).
In some embodiments, controller 605 is configured to provide the AHRS 607 with
one or
more of the speed data, the marker data, the geographic location (e.g.,
latitude, longitude, and
altitude) of the marker determined by the controller 605, an orientation
(e.g.,
azimuth/heading, grade/pitch, or bank/roll angles) of the guideway where the
detected marker
resides, the distance that the vehicle moved from a last marker as determined
by controller
605 based on the speed data and/or an indication that the vehicle is
stationary. The controller
605 is configured to determine that the vehicle is stationary based on the
speed data or an
instruction that indicates that the vehicle speed is equal to zero. In some
embodiments, the
controller 605 is configured to determine that the vehicle is stationary based
on an instruction
that indicates an amount of propulsion or force produced by a propulsion
system configured
to cause the guideway mounted vehicle to move is equal to zero.
AHRS 607 is an inertial navigation system that is configured to generate an
accurate dead
reckoning navigation solution between detected markers. In some embodiments,
the dead
reckoning navigation solution generated by the AHRS 607 is a 3D navigation
solution.
CA 02977730 2017-08-24
AHRS 607 comprises a sensor unit 609 and a processor 611. Processor 611 is
coupled with
sensor unit 609 and with controller 605. In some embodiments, the processor
611 and the
sensor unit 609 arc implemented as a microelectromechanical system (MEMS)
based AHRS
that is coupled with the controller 605 or included in the controller 605. In
some
embodiments, the sensor unit 609 and the processor 611 are self-calibrating.
In some
embodiments, sensor unit 609 and processor 611 arc individual components of
the system
600. For example, in some embodiments, system 600 comprises a sensor unit 609
and a
processor 611 without the sensor unit 609 and the processor 611 being embodied
in an
AHRS.
Sensor unit 609 comprises an accelerometer, a gyroscope, and a magnetometer.
In some
embodiments, sensor unit 609 comprises a temperature sensor or other suitable
sensor.
Sensor unit 609 is configured to generate sensor data based on information
gathered by one
or more of the accelerometer, the gyroscope, the magnetometer or the
temperature sensor. In
some embodiments, sensor unit 609 comprises more than one accelerometer,
gyroscope, or
magnetometer. In some embodiments, sensor unit 609 comprises three
accelerometers, three
gyroscopes, and three magnetometers. In some embodiments, sensor unit 609
comprises one
or more temperature sensors. In some embodiments, one or more of the
accelerometer(s), the
gyroscope(s), or the magnetometer(s) is a multi-axis accelerometer, a multi-
axis gyroscope,
or a multi-axis magnetometer. In some embodiments, the sensor unit 609
comprises three
dual-axis accelerometers, three dual-axis gyroscopes, and three dual-axis
magnetometers. In
some embodiments, one or more of the accelerometer(s), the gyroscope(s), or
the
magnetometer(s) is a three-axis accelerometer, a three-axis gyroscope, or a
three-axis
magnetometer. Processor 611 is configured to process the sensor data to
determine a vehicle
position based on the sensor data and the location information.
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CA 02977730 2017-08-24
In some embodiments, once AHRS 607 is initialized in terms of position, speed,
and
orientation, AHRS 607 is configured to determine the 3D navigation solution
independently
by double integration of a measured acceleration (dead reckoning) in all three
axes (e.g.,
Local North - East - Down). As a result, once a single marker is detected, a
full 3D
navigation solution is provided for use by the controller 605 to establish the
location
information train position and the direction of movement of the vehicle along
the guideway.
In some embodiments, the 3D navigation solution comprises one or more of a
vehicle
position in terms of AHRS body coordinates, a vehicle velocity in terms of
AHRS body
coordinates, a vehicle acceleration in terms of AHRS body coordinates, a
vehicle orientation
in local North - East - Down coordinates, or an angular rate in local North -
East - Down
coordinates. In some embodiments, AHRS body coordinates are defined as (1) X -
forward
along the vehicle's "waterline". (2) Y - left perpendicular to the vehicle's
"waterline", and (3)
Z - down perpendicular to the train's "waterline". In some embodiments, the
local North -
East - Down coordinates are defined as (1) North - toward the earth's local
magnetic north,
(2) East - toward east corresponding to the earth's local magnetic north, and
(3) Down -
toward the earth's center of gravity.
In some embodiments, processor 611 processes the sensor data via a filtering
algorithms such
as a Kalman filter to generate the 3D navigation solution. The 3D navigation
solution
includes an orientation, angular rate, acceleration, velocity, and position of
the guideway
mounted vehicle. In some embodiments, the orientation and/or the angular rate
are
determined with respect to the guideway. In some embodiments, the processor
611 processes
data from an external system or sensor such as the distance the vehicle moved
as determined
by the controller 605, the location information determined by the controller
605, or raw data
provided to the processor 611 such as the speed data generated by the speed
detector 601 to
generate one or more components of the 3D navigation solution. In some
embodiments, the
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CA 02977730 2017-08-24
processor 611 is configured to receive and process speed data generated by a
tachometer, a
non-wheel based speed measurement system, a GPS, and/or other suitable
localization system
or sensor to generate one or more components of the 3D navigation solution. In
some
embodiments, processor 611 is configured to receive and process raw data such
as marker
data generated by marker sensor 603 to generate one or more components of the
3D
navigation solution. In some embodiments. processor 611 is configured to
receive and
process marker data or localization data generated by a transponder tag
interrogator (e.g., an
RFID reader), a fusion sensor, or other suitable localization system or sensor
usable to
determine a specific guideway location to generate one or more components of
the 3D
navigation solution.
In some embodiments, the 3D navigation solution is provided to the controller
605 in two
sets. A first 3D navigation solution set is a compensated 3D navigation
solution based on the
distance the vehicle moved as determined by the controller 605 and the speed
data supplied
by the controller 605. The second 3D navigation solution set is a non-
compensated 3D
navigation solution that is not compensated based on the distance the vehicle
moved as
determined by the controller 605 and the speed data supplied by the controller
605. In some
embodiments, the compensated 3D navigation solution set and the non-
compensated 3D
navigation solution set are provided to the controller 605 simultaneously.
Because the processor 611 is configured to process the sensor data, the
location information,
and/or raw speed data, marker data, or other localization information, the
processor 611 is
capable of generating a vehicle position that has a minimal positioning error
as a result of
integration drift. Integration drift sometimes occurs in vehicle positioning
solutions if the
position of the vehicle is determined based on accelerometers, tachometer, and
marker data
alone. In some embodiments, AHRS 607 is configured to control an integration
drift less
than a threshold value that is dependent upon the overall required system
throughput (ex.
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CA 02977730 2017-08-24
Less than or equal to 30 meters after one minute of dead reckoning) to
maintain a positioning
error within expected bounds. In some embodiments, AHRS 607 is configured to
provide
dead reckoning positioning re-localization based on an external marker such as
a transponder
tag to minimize the positioning error when an external marker is detected. In
some
embodiments, AHRS 607 is configured to provide dead reckoning positioning
compensation
based on external source data, such as GPS data or a distance the vehicle
moved determined
by the controller 605 based on the speed data to minimize the positioning
error during dead
reckoning. In some embodiments, the AHRS 607 is configured to improve the
navigation
solution and its associated positioning error based on specific constraints
applied to the
railway system by implementing static navigation solution constraints such as
a zero speed
(for the Y and Z axis in the AHRS body coordinates). In some embodiments, the
AI-IRS 607
is configured to avoid unnecessary accumulation of positioning error when the
train is
stopped by implementing dynamic navigation solution constraints such as zero
speed (for the
X axis in the AHRS system body coordinates). In some embodiments, when the
vehicle
comes to a stop, and stand still conditions are verified, the controller 605
is configured to
update the AHRS 607 accordingly. The AHRS 607 uses the stand still indication
received
form the controller 605 to eliminate drift errors during the period that the
vehicle does not
move.
Because the processor 611 generates a full 3D navigation solution, the
direction that the
vehicle moves on the guideway is capable of being established upon generation
of the 3D
navigation solution. Because the 3D navigation solution is based, at least in
part, on the
sensor data generated by the sensor unit 609, the processor 611 and/or the
controller 605 are
capable of generating the vehicle position and/or the location information
describing the
position of the vehicle on the guideway once a single marker is observed. By
establishing the
position of the vehicle on the guideway after a single marker is observed, the
controller 605 is
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CA 02977730 2017-08-24
able to maintain operation of the vehicle if a marker is missed, which is
sometimes a problem
in conventional vehicle localization systems that depend on observing two
adjacent
consecutive transponder tags to establish the position of the vehicle and the
direction of
movement of the vehicle on the guideway. In some embodiments, each time a
marker is
observed, processor 611 is configured to localize or re-localize the vehicle
position included
in the 3D navigation solution.
Controller 605 is configured to update the location information based on at
least the vehicle
position included in the 3D navigation solution and to determine a direction
that the vehicle
moved based on the updated location information. In some embodiments, the
controller 605
uses the 3D navigation solution to determine the direction that the vehicle
moved.
After the marker sensor 603 detects an object or marker, controller 605
periodically updates
the processor 611 with the distance traveled based on the speed data. In some
embodiments,
controller 605 is configured to update processor 611 with the distance
traveled about every 70
milliseconds (msec). In some embodiments. controller 605 is configured to
update processor
611 with the distance traveled more often than about every 70 msec. In other
embodiments,
controller 605 is configured to update processor 611 with the distance
traveled less often than
about every 70 msec.
Using the location information and the distance traveled provided by the
controller 605,
processor 611 generates the 3D navigation solution and communicates the 3D
navigation
solution to the controller 605 multiple times every second. In some
embodiments, controller
605 is configured to compare the direction that the vehicle moved with an
expected direction
of travel based on guideway data stored in a memory, and the controller 605 is
configured to
determine the vehicle is off the guideway based on a change in the direction
that the vehicle
moved from the expected direction of travel if the change in the direction
that the vehicle
moved occurred within a predetermined period of time. In some embodiments, the
CA 02977730 2017-08-24
predetermined period of time is less than or equal to the period within which
the processor
611 updates controller 605 or the controller 605 updates processor 611.
In some embodiments, controller 605 is configured to compare the location
information with
the vehicle position generated by the processor 611 to determine if a
difference between the
location information and the vehicle position is within a predetermined
threshold range. In
some embodiments, controller 605 is configured to compare the distance
traveled based on
the speed data with a distance traveled based on the 3D navigation solution to
determine if
the difference is within a predetermined threshold range. If the difference
between either the
vehicle position and the location information or the distance traveled based
on the speed data
and the distance traveled based on the 3D navigation solution is outside the
threshold range,
the difference indicates that one of the vehicle position, the location
information, the distance
traveled based on the speed data or the distance traveled based on the 3D
navigation solution
is implausible or incorrect.
In some embodiments, an implausible or incorrect 3D navigation solution is
indicative that a
slip or slide condition has occurred. A slip condition is a situation in which
a wheel of the
vehicle slips or spins with respect to the guideway and the vehicle moves a
distance that is
less than a distance that corresponds with the amount the wheel spins based on
a diameter of
the wheel. A slide condition is a situation in which a wheel of the vehicle
slides with respect
to the guideway and the vehicle moves a distance that is greater than a
distance that
corresponds with the amount the wheel spins based on the diameter of the
wheel. If the
difference is outside the threshold range, the controller 605 is configured to
generate an
indication that a slip or slide condition has occurred. In some embodiments,
the controller
605 is configured to determine that the vehicle is in a slide condition based
on an indication
that the vehicle is stationary based on the speed data and an indication that
the vehicle
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CA 02977730 2017-08-24
changed position based on the sensor data from a first position to a second
position different
from the first position.
In some embodiments, the controller 605 is configured to determine a velocity
and an
acceleration of the vehicle based on the speed data. The controller 605
compares the velocity
and the acceleration portions of the non-compensated 3D navigation solution
set provided to
the controller 605 by the processor 611 with the velocity and acceleration
determined based
on the speed data to identify if the vehicle is in a slip or a slide
condition.
Based on the comparison, the controller 605 is configured to determine that
the vehicle is in a
slip or a slide condition if the velocity and/or the acceleration portions of
the non-
compensated 3D navigation solution set and the corresponding velocity and/or
the
acceleration determined based on the speed data are mismatched by more than
the acceptable
range for a non-slip/slide state.
If a slip or a slide condition is determined to have occurred, the controller
605 is configured
to prevent transmission of one or more of the location information or the
distance the vehicle
moved that is calculated based on the speed data to the processor 611. By
preventing
transmission of the location information and/or the distance traveled to the
processor 611, the
processor 611, is caused to generate the 3D navigation solution based on the
sensor data
alone or in combination with the location information. In some embodiments, if
the
controller 605 determines the vehicle is in a slip or a slide condition, the
controller 605 is
configured to stop sending the location information, the distance the vehicle
moved from the
last marker and/or the speed data to the processor 611. In some embodiments,
as a result, the
compensated and the non-compensated 3D navigation solution sets will then be
identical.
If a slip or slide condition is determined by the controller 605 to have
occurred, then the
controller 605 is configured to determine the location information and/or the
distance the
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CA 02977730 2017-08-24
vehicle moved based on the 3D navigation solution or one or more components
thereof such
as the vehicle position generated by the processor 611 until a marker is
detected by the
marker sensor 603. For example, if the marker data is based on a first object
detected by the
marker sensor 603, then the controller 605 is configured to determine the
location
information based only on the vehicle position generated by the processor 611
if a slip or
slide condition is determined to have occurred until a second object is
detected by the marker
sensor 603. Because the slip or slide condition is tolerated until the marker
sensor 603
detects another object, a quantity of markers needed to keep a vehicle in
operation on the
guideway is capable of being reduced. For example, the system 100 makes it
possible to
optionally place markers at locations along the guideway where high vehicle
position
accuracy is desired such as at switch zones or platforms.
The controller 605 is configured to determine the slip or slide condition has
ended if the non-
compensated 3D navigation solution set and the velocity and acceleration
determined based
on the speed data are within the acceptable range for the non-slip/slide
state. After the
controller 605 determines the slip or the slide condition has ended, the
controller 605 starts
sending the location information, the distance the vehicle moved from the last
marker and/or
the speed data to the processor 611 again.
During non-slip or slide periods, the 3D navigation solution is "corrected" by
the distance
traveled calculated by the controller 605 based on the speed data. This
ensures that the 3D
navigation solution, during the non-slip or slide periods, is at least as
accurate as the distance
traveled calculated by controller 605.
Because the position error due to integration drift over time is minimized by
the AHRS 607,
the controller 605 is capable of tolerating periods in which the vehicle is in
a slip or slide
condition without exceeding a position uncertainty limit that would otherwise
affect the
operation of the vehicle. In vehicle localization systems that determine a
vehicle position
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CA 02977730 2017-08-24
based on accelerometers, tachometers and marker data alone, vehicle
positioning uncertainty
grows rapidly during periods in which the vehicle is in a slip or a slide
condition, which
results in a position being lost when a maximum position uncertainty threshold
is exceeded.
Al IRS 607 makes it possible to tolerate a slip or slide period or distance
because the location
information and the vehicle position determined by the controller 605 and the
processor 611
are updated based on the sensor data, which helps to keep the position
uncertainty below the
maximum positioning uncertainty threshold following a slip or slide condition
before another
marker is detected to update the location information generated by the
controller 605.
In some embodiments, controller 605 is configured to determine the vehicle is
off the
guideway. In some embodiments, if the vehicle is determined to be off the
guideway, then
the controller 605 determines that a derailment of the vehicle from the
guideway has
occurred. If the vehicle is determined to be off the guideway, the controller
605 is configured
to generate an indication that the vehicle is off the guideway. Based on the
determination
that the vehicle is off the guideway, in some embodiments, the controller 605
is configured to
stop the vehicle from operating. For example, if the controller 605 determines
the vehicle is
off the guideway, the controller 605 is configured to cause the wheels of the
vehicle to stop
moving. Such a feature is helpful in preventing a vehicle that is off the
guideway from being
driven from a derailment position to another position by way of a force
generated by the
wheels of the vehicle, for example. In other words, the controller 605 is
configured to
generate an instruction to cut off vehicle propulsion.
In some embodiments, the controller 605 is configured to determine the vehicle
is off the
guideway based on a change in the orientation from an expected orientation of
the vehicle
that occurs within a predetermined period of time. For example, if the
processor 611 is
configured to communicate the 3D navigation solution to the controller 605
about every 70
msec, and the controller is configured to update the processor 611 with the
location
39
CA 02977730 2017-08-24
information and/or the distance traveled every 70 msec, then an unexpected
change in
orientation of the vehicle that occurs in less than about 140 msec is
indicative that the vehicle
has unexpectedly moved off of the guideway. In some embodiments, the
predetermined
period of time is greater than about 140 msec. The expected orientation of the
vehicle is one
or more of a current orientation of the vehicle with respect to the guideway
determined by the
processor 611 or an orientation of the vehicle with respect to the guideway
associated with a
known position on the guideway that is stored in a memory. Controller 605 is
configured to
compare the orientation of the vehicle with the expected orientation of the
vehicle, to
determine if an unexpected change in the orientation of the vehicle occurs
within the
predetermined period of time. In some embodiments, the predetermined period of
time
provides as small of a window as possible to provide a near instantaneous
determination that
an unexpected change in orientation of the vehicle has occurred. For example,
upon an
unexpected derailment of the vehicle from the guideway, the vehicle position
and the
orientation of the vehicle will have a sudden and significant change. For
example, in a case
of a vehicular rollover from an upright position with respect to the guideway
to a side of the
vehicle, the vehicle will experience a roll angle of about 90 degrees. In some
cases in which
the vehicle is unexpectedly off the guideway, the heading angle will have a
significant
change with respect to the guideway heading. In some other cases, the vehicle
position may
be significantly off the guideway location.
In some embodiments, controller 605 is configured to determine that the
vehicle is off the
guideway based on the change in the orientation of the vehicle and a decrease
in acceleration
based on the sensor data. For example, if the controller 605 determines that a
change in the
orientation of the vehicle has occurred and, based on the speed data or the 3D
navigation
solution, the vehicle suddenly decelerates with an instruction known to the
controller 605, the
controller determines that the vehicle is off the guideway.
CA 02977730 2017-08-24
In some embodiments, if the vehicle is not in a slip or a slide condition,
e.g., the difference
between the vehicle position and the location information is within the
threshold range, the
controller 605 is configured to calibrate a diameter of a wheel of the vehicle
based on the
vehicle position, the marker data, and the speed data. The distance traveled
based on speed
data such as that generated by a tachometer is a function of the wheel
diameter. Therefore,
accurate speed data measurement relies on accurate calibration of the wheel
diameter.
Typically calibration is performed by adjusting the wheel diameter based on a
known
distance between two known markers and a number of tachometer pulses measured
between
the two known markers. The wheel calibration accuracy is sensitive to marker
detection
errors (e.g. transponder detection errors, installation errors, footprint) and
spin/slide related
errors. To improve the accuracy of the wheel calibration and to increase the
tolerance for
some detection errors, the controller 605 is configured to calibrate the
diameter of the wheel
using the vehicle position generated by the processor 611, which is based on
the sensor data.
The controller 605 is then able to determine the location information based on
the speed data
and the calibrated diameter of the wheel. In some embodiments, the wheel
diameter
calibration is based on the difference between two AHRS inputs in proximity to
the detected
object or marker. In some embodiments, the AHRS 607 is configured to
specifically
communicate with objects or markers that are marked with calibration tags to
perform the
wheel diameter calibration.
Figure 7 is a flowchart of a method 700 of determining a position of a
guideway mounted
vehicle, in accordance with one or more embodiments. In some embodiments, one
or more
steps of method 700 is implemented by a processor such as processor 611
(Figure 6) or a
controller such as 605 (Figure 6).
In step 701, a speed of a vehicle is detected using a speed detector
configured to generate
speed data associated with the vehicle.
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CA 02977730 2017-08-24
In step 703, an object is detected along a wayside of a guideway along which
the vehicle is
configured to move using a marker sensor configured to generate marker data
based on the
detection of the object.
In step 705, the controller calculates a distance the vehicle moved based on
the speed data
and the marker data.
In step 707, the controller generates location information based on the
distance the vehicle
moved and the marker data.
In step 709, sensor data is generated based on information gathered by one or
more of an
accelerometer, a gyroscope, or a magnetometer.
In step 711, the processor processes the sensor data using to determine a
vehicle position
based on the sensor data and the location information.
In step 713, the controller compares the location information with the vehicle
position to
determine if a difference between the location information and the vehicle
position is within a
predetermined threshold range. If the difference is outside the threshold
range, the controller
determines the vehicle is in a slip or slide condition. Based on the
determination that the
vehicle is in a slip or a slide condition, the controller prevents
transmission of the location
information to the processor. If the controller determines that the vehicle is
in a slip or a slide
condition, the controller determines the location information based only on
the vehicle
position provided by the processor.
In step 715, the controller optionally generates an indication that the
vehicle is stationary
based on the speed data. The controller is configured to determine the vehicle
is in a slide
condition based on the indication that the vehicle is stationary based on the
speed data and a
change in vehicle position based on the sensor data from a first position to a
second position
different from the first position.
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CA 02977730 2017-08-24
In step 717, the controller updates the location information based on the
vehicle position.
In step 719, the controller determines a direction the vehicle moved based on
the updated
location information. The controller compares the direction that the vehicle
moved with an
expected direction of travel based on guideway data stored in a memory. If a
change in the
direction that the vehicle moved from the expected direction of travel
occurred within a
predetermined period of time, the controller determines the vehicle is off the
guideway.
In step 721, the processor processes orientation data associated with an
orientation of the
vehicle included with the sensor data to determine an orientation of the
vehicle with respect
to the guideway.
In step 723, the controller compares the orientation of the vehicle with an
expected
orientation of the vehicle. The expected orientation of the vehicle is one or
more of a current
orientation of the vehicle determined by the processor or a stored orientation
of the vehicle
associated with the guideway. If the controller determines that the vehicle
unexpectedly
changed orientation within a predetermined period of time, the controller
determines the
vehicle is off the guideway. In some embodiments, the controller determines
that the vehicle
is off the guideway based on the change in the orientation of the vehicle and
a decrease in
acceleration based on the sensor data.
In step 725, the controller calibrates a diameter of a wheel of the vehicle
based on the vehicle
position, the marker data, and the speed data. The location information is
based on the speed
data and the calibrated diameter of the wheel if the difference is within the
threshold range,
indicating the vehicle is not in a slip or a slide condition.
Figure 8 is a functional flowchart of a method 800 for integrating an AHRS
into a VOBC
positioning system, in accordance with one or more embodiments. In some
embodiments,
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CA 02977730 2017-08-24
one or more steps of method 800 is implemented by a processor such as
processor 611
(Figure 6) of AHRS 607 (Figure 6) or a controller such as 605 (Figure 6).
In step 801, marker data is optionally received by the controller. In step
803, the controller
determines if marker data was received. If yes, the method continues to steps
805 and 807.
If no, then the method continues to step 809.
In step 805. the controller determines the location of the vehicle based on
the marker data and
communicates the location information to the processor of the AHRS in terms of
the location
of the marker.
In step 807, the controller calibrates the wheel diameter based on the marker
data and the
speed data received by the controller in step 811.
In step 811, speed data is received by the controller. The speed data is
usable, for example, to
determine the distance the vehicle traveled from the last marker and/or for
wheel diameter
calibration.
In step 809, the controller determines the distance the vehicle traveled from
the last marker
detected based on the received marker data associated with detecting the last
marker, the
speed data, and the calibrated wheel diameter.
In step 813, the controller determines if the vehicle is off the guideway. If
yes, then the
controller cuts off propulsion of the vehicle in step 815. If no, then the
method continues to
step 817 in which the controller determines if the vehicle is in a slip or a
slide condition. If
yes, the method continues to step 803 to re-initialize the position of the
vehicle. If no, then
the process continues to step 819, and the controller communicates the
distance that the
vehicle traveled from the last marker to the AHRS.
In step 819, the AHRS processes the marker location, the vehicle location, the
distance the
vehicle traveled, the speed data, and/or the sensor data generated by the
sensors of the AHRS
44
CA 02977730 2017-08-24
to generate the compensated 3D navigation solution and the non-compensated 3D
navigation
solution usable to determine the location of the vehicle until a next marker
is detected and
new marker data is received by the controller.
Figure 9 is a graph 900 showing experimental results demonstrating the
effectiveness of the
system 600 at reducing wheel calibration errors, in accordance with one or
more
embodiments. Graph 900 depicts the distance traveled (m), speed (m/s),
positioning error
(in) and the position error over travelled distance percentage (%) assuming
the integration
drift is 30 m after one minute, with an initial vehicle speed of 72 km/h and a
vehicular
acceleration of 0.5 m/s2 on a level guideway.
Based on the above example, a 0.25% wheel diameter error is achievable where
the wheel
calibration process is constrained to 5.0 seconds and no spin or slide occurs
during the wheel
calibration process. This results in a position error of 0.25% of the distance
traveled from the
last observed marker if no spin or slide occurs. For example, if the distance
to a next marker
is 2 km, and no markers are installed between a first marker and the next
marker, the
positioning error at the next marker will be 5 m. This is a significant
improvement with
respect to situations in which the wheel diameter error is more than 1%.
Figure 10 is a graph 1000 showing experimental results demonstrating the
effectiveness of
the system 600 at reducing drift error in a slide condition, in accordance
with one or more
embodiments. Graph 1000 depicts the distance traveled (m), speed (m/s),
positioning error
(in) and the position error over travelled distance percentage (%) assuming
the initial vehicle
speed is 72 km/h, the vehicle brakes to a stop at 0.5 m/s2 on a level
guideway, and a slide
occurs. In this example, the braking time is approximately 40 seconds and the
positioning
error accumulated during the slide period (i.e. 40 seconds) is approximately
18 m. This is a
significant improvement with respect to situations in which only few seconds
of slide are
allowed before the vehicle position is lost to the controller which would
usually cause the
CA 02977730 2017-08-24
vehicle to be braked to a stop via an emergency brake actuated by the
controller, for example.
The above-described systems and methods help make it possible to position
transponder tags
or other markers, which are used to localize and/or re-localize the train
position, only at
locations of interest where a smaller position uncertainty is desired. This
will result at cost
savings as less equipment, if transponder tags are used, has to installed and
maintained. The
above-described systems and methods help VOBC's to better tolerate slip and or
slide
conditions that cause position loss. The above-described systems and methods
provide a
more accurate dead reckoning position between markers as a result of a more
accurate wheel
diameter calibration process and the 3D navigation solution sets generated by
the AHRS.
The above-described systems and methods make it possible to detect a train
derailment based
on the AHRS 3D navigation solution and the determination of a sudden and
significant
change of the train location and orientation with respect to the expected
location and
orientation.
An aspect of this description relates to a system comprising a speed detector,
a marker sensor,
a controller, a sensor unit, and a processor. The speed detector is configured
to generate
speed data associated with a movement of a vehicle. The marker sensor is
configured to
generate marker data based on a detection of an object along a wayside of a
guideway along
which the vehicle is configured to move. The controller is coupled with the
speed detector
and the marker sensor. The controller is configured to calculate a distance
the vehicle moved
based on the speed data and the marker data. The controller is also configured
to generate
location information based on the distance the vehicle moved and the marker
data. The
controller is further configured to generate an indication the vehicle is
stationary based on the
speed data. The sensor unit comprising an accelerometer, a gyroscope, and a
magnetometer.
The sensor unit is configured to generate sensor data based on information
gathered by one or
more of the accelerometer, the gyroscope, or the magnetometer. The processor
is coupled
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CA 02977730 2017-08-24
with the sensor unit and the controller. The processor is configured to
process the sensor data
to determine a vehicle position based on the sensor data and the location
information. The
controller is additionally configured to compare the location information with
the vehicle
position to determine if a difference between the location information and the
vehicle
position is within a predetermined threshold range.
Another aspect of this description relates to a method comprising detecting a
speed of a
vehicle using a speed detector configured to generate speed data associated
with the vehicle.
The method also comprises detecting an object along a wayside of a guideway
which the
vehicle is configured to move using a marker sensor configured to generate
marker data
based on the detection of the object. The method further comprises
calculating, using a
controller, a distance the vehicle moved based on the speed data and the
marker data. The
method additionally comprises generating location information based on the
distance the
vehicle moved and the marker data. The method also comprises generating sensor
data based
on information gathered by one or more of an accelerometer, a gyroscope, or a
magnetometer. The method further comprises processing the sensor data using a
processor to
determine a vehicle position based on the sensor data and the location
information. The
method additionally comprises comparing the location information with the
vehicle position
to determine if a difference between the location information and the vehicle
position is
within a predetermined threshold range.
A further aspect of this description relates to a system comprising a
tachometer, a marker
sensor, a controller, and a navigation unit. The tachometer is configured to
generate rotation
data associated with a rotation of a wheel of a vehicle. The marker sensor is
configured to
generate marker data based on a detection of an object along a wayside of a
guideway along
which the vehicle is configured to move. The controller is coupled with the
tachometer and
the marker sensor. The controller is configured to calculate a speed at which
the vehicle
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CA 02977730 2017-08-24
moves based on the rotation data and a diameter of a wheel of the vehicle. The
controller is
also configured to calculate a distance the vehicle moved based on the speed
data and the
marker data. The controller is further configured to generate location
information based on
the distance the vehicle moved and the marker data. The navigation unit
comprises a
processor, an accelerometer, a gyroscope, and a magnetometer. The navigation
unit is
configured to generate a vehicle position based on sensor data and the
location information.
The sensor data is gathered by one or more of the accelerometer, the
gyroscope, or the
magnetometer. The controller is additionally configured to determine if a
difference between
the location information and the vehicle position is within a predetermined
threshold range,
and calibrate the diameter of the wheel based on the vehicle position, the
marker data and the
speed data if the difference is within the threshold range.
It will be readily seen by one of ordinary skill in the art that the disclosed
embodiments fulfill
one or more of the advantages set forth above. After reading the foregoing
specification, one
of ordinary skill will be able to affect various changes, substitutions of
equivalents and
various other embodiments as broadly disclosed herein.
48
