ON-BOARD COMMUNICATION DEVICE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an on-board communication device provided
on a mobile body which conducts communication with a trackside communication
device.
Description of the Related Art
As a background art of this technical field, Japanese Patent Laid-Open No.
2001 -186606 (Patent Document 1) can be cited. This Gazette proposes a method
in which a test antenna for diagnosing a reception device of an on-board
communication device is prepared in the on-board communication device other than
an antenna which conducts communication with a trackside communication device,
and the reception device is diagnosed when the on-board communication device is
started.
Moreover, Japanese Patent Laid-Open No. 2008-99515 (Patent Document 2)
proposes a method in which either one of doubled on-board communication devices
is made an active controller and the other is made a standby controller, and by
providing a testing device for diagnosing the active controller and the standby
controller, determination on normality is made so that a failure in the device can be
detected.
In general, transmission/reception of message information between the
trackside communication device installed on a ground side and the on-board
communication device is performed as follows. First, the on-board communication
device transmits an electric power wave to the trackside communication device and
feeds power. Then, the trackside communication device is started by this power
and repeatedly transmits the message information to the on-board communication
device, and the on-board communication device receives this. Therefore, in order
that the on-board communication device utilizes the message information received
from the trackside communication device so as to safely control the mobile body, the
message information from the trackside communication device is required to be
reliably received.
However, if a reception portion of the on-board communication device fails, the
information from the trackside communication device cannot be received, and the
trackside communication device cannot be distinguished. Thus, in order to reliably
receive the message information from the trackside communication device, selfdiagnosis
of the reception portion of the on-board communication device needs to be
made.
In the single-system on-board communication device illustrated in Patent
Document 1, in order to realize safe running of the mobile body, soundness can be
checked by making a diagnosis of the reception device at start of the on-board
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communication device, but while the on-board communication device is operating
over time, the diagnosis of the reception device cannot be made during that period.
Thus, even if the reception device fails, the failure cannot be detected, and the
trackside communication device can no longer distinguished. Thus, the mobile body
might be stopped depending on the case.
Moreover, in a configuration illustrated in Patent Document 1, if a signal is sent
out for a diagnosis in order to confirm whether or not the reception device of itself is
normal during running of the mobile body, a signal sent from the trackside
communication device collides with the diagnosis signal of the reception device of
itself, and there is a concern that the signal from the trackside communication device
is affected. Thus, in the end, communication with the trackside communication
device might fail. Therefore, with the single-system on-board communication device
illustrated in Patent Document 1, a failure cannot be detected while the mobile body
operates over time, and even if a diagnosis of the reception device of itself is made
during running, communication with the trackside communication device is interfered
with.
In order to solve such points, in Patent Document 2, the on-board
communication device is doubled, and a testing device for diagnosing the active
controller and the standby controller is provided so as to enable a diagnosis of the
reception device. Thus, during running of the mobile body, communication can be
conducted without interfering with the communication with the trackside
communication device, but since the antenna conducting communication with the
trackside communication device is not doubled, while an on-board communication
device body is doubled, a space and a cost for mounting the device increase.
SUMMARY OF THE INVENTION
In order to solve the above-described problems, the on-board communication
device in the present invention includes a test signal generation circuit for generating
a test signal simulating a message signal of the trackside communication device, a
test signal transmission antenna for transmitting a signal generated in the test signal
generation circuit to an on-board reception antenna in the on-board communication
device, and a test signal transmission path for transmitting the signal generated in
the test signal generation circuit to a decoding circuit of the on-board communication
device without via the test signal transmission antenna.
According to the present invention, since it is a single-system on-board
communication device, a cost does not increase. Moreover, the reception device of
itself can be diagnosed without a collision with a message signal from the trackside
communication device. Thus, even during high-speed running, self-diagnosis can
be made while stable communication is conducted with the trackside communication
device. Problems, configurations and advantageous effects other than the above
will be made apparent from description of the following embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
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FIG. 1 is an outline configuration view of an on-board communication device in
an embodiment 1 of the present invention;
FIG. 2 is an outline configuration view of an on-board communication device in
a conventional example;
FIG. 3 is a view for explaining a relation between communication movement
distances of a test signal and a message signal of a trackside communication device
and a communicable range in the conventional example;
FIG. 4 is a view for explaining a relation between communication movement
distances of a test signal and a message signal of a trackside communication device
and a communicable range in the embodiment 1 of the present invention;
FIG. 5 is an outline configuration view of an on-board communication device in
an embodiment 2 of the present invention;
FIG. 6 is an explanatory view when output intensity of a test signal wave to be
transmitted is set to lowest reception intensity or more for performing trackside
communication device detection in test signal transmission processing;
FIG. 7 is an explanatory view when output intensity of a test signal wave to be
transmitted is set to less than the lowest reception intensity for performing trackside
communication device detection in test signal transmission processing; and
FIG. 8 is an outline configuration view of an on-board communication device in
the embodiment 3 of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments will be described below by using FIG. 1, FIG. 2, FIG. 3, and FIG.
4.
(Embodiment 1)
FIG. 1 is an outline configuration view illustrating an embodiment in which a
diagnosis function according to the present invention is applied, and FIG. 2 is an
outline configuration view illustrating an embodiment in a conventional technology.
FIG. 3 is a view for explaining an operation of communication processing of an onboard
communication device and a trackside communication device in a case of the
conventional example, and FIG. 4 is a view for explaining an operation of
communication processing of an on-board communication device and a trackside
communication device of this embodiment.
A trackside communication device 102 illustrated in FIG. 1 and FIG. 2 is
installed on a ground side and is started by receiving an electric power wave from an
on-board communication device 101 and gaining electric power and conducts
communication with the on-board communication device 101. In general, as long as
the electric power wave is continuously received, the trackside communication device
102 continuously transmits a same message signal at all times repeatedly. A
message length sent by the trackside communication device is fixed for each
trackside communication device, and there are a Long message transmitting
approximately 1000 bits and a Short message transmitting approximately several
hundred bits in general, but the length of the message is not limited to the two types
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and a case of three types or more also exists. The on-board communication device
101 has specific decoding means according to the respective message lengths for
received message signals with different message lengths.
The on-board communication device 101 according to the conventional
technology in FIG. 2 is provided with a reception portion 106 for receiving the
message signal with magnetic flux intensity of a predetermined value or more
through electromagnetic coupling with the trackside communication device 102 is
mounted. In the reception portion 106, a reception intensity detection circuit 112 for
detecting reception intensity of the message signal received from the trackside
communication device 102, a trackside communication device detection
determination portion 113, a demodulation circuit 114 for demodulating the received
message signal, a decoding circuit 115 for decoding message information from a
demodulated signal, and the like.
Moreover, the on-board communication device is provided with a test signal
generation circuit 109 for generating a test signal, a test signal transmission
notification circuit 116 for notifying transmission of a test signal to the on-board
communication device detection determination portion 113, means for transmitting
the test signal to the reception portion 106 of the on-board communication device
101 by using a test signal transmission antenna 110, a power wave transmission
portion 104 and a power wave transmission antenna for supplying an electric power
wave to the trackside communication device 102, and a transmission/reception
antenna for conducting transmission/reception with the trackside communication
device 102 and the test signal transmission antenna.
Furthermore, the on-board communication device 101 is provided with a
control portion 103 provided with a function for instructing the test signal generation
circuit to send out a test signal and a function in which determination of a test result
is made and whether or not a signal received from the trackside communication
device 102 is correctly received, demodulated/decoded is determined and if it is an
abnormal signal, an output of the signal is stopped and abnormality message
detection is outputted.
In FIG. 1 which is a first embodiment of the present invention, in addition to the
configuration illustrated in FIG. 2, a test signal transmission path 111 which is means
for transmitting the test signal generated in the test signal generation circuit 109 to
the decoding circuit 115 in the reception portion 106 of the on-board communication
device 101 without via the test signal transmission antenna 110 is provided. By
means of this configuration, the reception portion 106 of the on-board communication
device 101 is diagnosed while plural types of the message signals with different
message lengths are handled.
In the following description of this embodiment, the description will be made on
the premise that there are two types of message signals sent from the trackside
communication device 102, but it is neediess to say that the present invention can be
applied to a case with three types or more.
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ln the present invention, in order to diagnose the reception portion, first, on the
basis of an instruction of the control portion 103, a test signal is generated in the test
signal generation circuit 109 of the test signal transmission portion 108, and a Long
message signal generated by the test signal generation circuit 109 is inputted into the
decoding circuit 115 in the reception portion 106 via the test signal transmission path
111.
On the other hand, it is configured such that a Short message signal generated
by the test signal generation circuit 109 is transmitted from the test signal
transmission antenna 110 and received by the transmission/reception antenna 107.
That is, by transmitting the Short message signal with short transmission time
from the test signal transmission antenna 110, a path of the reception device from
the transmission/reception antenna 107 is diagnosed, while the Long message signal
with longer transmission time is inputted into the decoding circuit without via the test
signal transmission antenna 110 and a diagnosis of the decoding circuit and after is
made.
The fact that the test signal is being transmitted is transmitted also to the
trackside communication device detection determination portion 113 via the test
signal transmission notification circuit 116.
By using FIG. 3 and FIG. 4, a situation of a case in which a failure such as a
collision, interference or the like (hereinafter referred to as "collision") occurs between
the message signal from the trackside communication device 102 and the test signal
will be described.
The message signal from the trackside communication device 102 has a
certain range of a receivable distance. Here, it is assumed that a receivable contact
distance 305 is T (fixed length), and transmission speeds of the message from the
trackside communication device 102 and a test signal message are x. At this time,
by assuming a running speed of the mobile body is V, the number of bits that can be
received within the contact distance T decreases with a rise of the running speed V
of the mobile body.
As illustrated in FIG. 3, it is assumed that a movement distance required for
transmitting one message of the Short message during running is TShort 306, a
movement distance required for transmitting one message of the Long message is
Tiong 307, and Tshort + Tiong ^ T holds true. At this time, during high-speed running, if
the mobile body is entering the receivable contact range of the trackside
communication device transmitting the Short message signal during transmission of
a test signal Short message 301, a Short message signal 303 continuously
transmitted from the trackside communication device collides with the test signal
Short message 301 and crushes one message of the Short message 303 of the
trackside communication device. However, in this case, if the control portion
instructs stop of transmission, demodulation, and decoding of the test signal on the
basis of detection of the trackside communication device, the subsequent Short
message signal can be received in the remaining receivable contact distance.
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However, in a case that a Long message 304 is repeatedly sent from the
trackside communication device 102 in the middle of transmission of a Long
message 302 as the test signal, if one of the Long messages 304 is crushed, in this
case, even if the control portion instructs stop of the transmission, demodulation, and
decoding of the test signal on the basis of detection of the trackside communication
device, the subsequent Long message cannot be received in the remaining
receivable contact distance. Thus, the Long message 304 from the trackside
communication device 102 is missed.
Thus, in the present invention, as illustrated in FIG. 1, a Long message test
signal 401 is not transmitted via the antenna 110 but is directly inputted into the
decoding circuit 115 by using the test signal transmission path 111. Specifically,
since the control portion, the reception portion and the test signal transmission
portion are configured by one FPGA (field-programmable gate array), the
transmission, demodulation, and decoding of the Long message test signal 401 can
be immediately stopped when the message signal from the trackside communication
device 102 is detected.
Thus, when this embodiment is applied, in FIG. 4 illustrating a collision relation
between the message signal and the test signal, similarly to the case in FIG. 3,
assuming that, when TShort + T|0ng < T holds true, a movement distance in a case of a
collision with the message signal from the trackside communication device 102 at
transmission of the Long message test signal 401 is TC402, it can be regarded as
TC « Tshort, and even in the case of a collision with the Long message signal 304
from the trackside communication device 102 at transmission of the Long message
test signal 401 in high-speed running, the repeatedly sent Long message signal 304
can be received. As a result, the message signal from the trackside communication
device 102 at self-diagnosis is not missed, and high reliability of the on-board
communication device 101 body can be maintained.
In order to avoid a collision between the message signal from the trackside
communication device 102 during running of the mobile body and the test signal,
there can be a method in which, in the mobile body, an installation place of the
trackside communication device is stored in advance, and the test signal is not
transmitted in the vicinity of the trackside communication device. However, if a
running distance of the mobile body is long or free running is allowed, that cannot be
easily handled by storing position information of all the trackside communication
devices, and moreover, a problem is caused that the installation place of the
trackside communication device is fixed at all times and cannot be moved. Thus, as
in the present invention, when the message signal from the trackside communication
device is detected, capability of immediate stop of decoding of the test signal or the
subsequent transmission of the test signal and of quick start of
demodulation/decoding of the message signal from the trackside communication
device is extremely useful and can be considered as a technology with wide
applicability.
(Embodiment 2)
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Subsequently, a second embodiment of the present invention will be described
by using FIG. 5 and FIG. 6. This embodiment is applied to a failure detection case
in which operation is not started though a message signal exceeding reception
detection intensity is received from the trackside communication device 102 in the
reception portion 106 of the on-board communication device 101, or a case in which
a message signal less than the reception detection intensity not requiring detection is
erroneously detected.
In this embodiment, as illustrated in FIG. 5, the reception portion 106 has a
reception intensity detection circuit 501 for detecting reception intensity of a message
signal received from the trackside communication device 102, a trackside
communication device detection determination portion 502, a demodulation circuit
503 for demodulating the received message signal, a decoding circuit 504 for
decoding message information from the demodulated signal, and the like.
In the reception portion 106 illustrated in FIG. 5, if the reception intensity
detection circuit 501 or the trackside communication device detection determination
portion 502 is abnormal, regardless of reception of the message signal with
predetermined reception intensity from the trackside communication device 102, a
series of functions of the reception portion 106 are not likely to operate. Then, as
the result, the trackside communication device 102 is missed.
On the other hand, if the message with the predetermined reception intensity
or less is received and a series of the functions of the reception portion 106 are
operated, it is likely that the message from the trackside communication device which
should not be received is erroneously detected or there is a concern that regardless
of non-presence of the trackside communication device 102, the control portion 103
executes processing assuming that the trackside communication device 102 is
present.
Such abnormality can be detected by conducting a test in which the output
intensity of a test signal wave to be transmitted is set to the lowest reception intensity
or more for performing the trackside communication device detection and a test in
which it is set to less than the lowest reception intensity in test signal transmission
processing as illustrated in FIG. 6 and FIG. 7. That is, if the test signal wave 601
set to the lowest reception intensity or more cannot be received or if a test signal
wave 603 set to less than the lowest reception intensity can be received, it can be
determined that the reception intensity detection circuit 501 or the trackside
communication device detection determination portion 502 fails.
The diagnosis of the reception intensity detection circuit 501 or the trackside
communication device detection determination portion 502 is basically made by
changing the signal intensity of the Short message transmitted from the test signal
generation circuit 109 via the test signal transmission antenna 110.
If the signal of the Short message is transmitted by using the test signal wave
601 set to the iowest reception intensity or more, it is substantially similar to that
performed in the embodiment 1, and if the control portion 103 confirms that the signal
with the same contents as the test signal instructed in the control portion is detected
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by the reception portion 106, it is determined that there is no problem with the
reception intensity detection circuit 501 or the trackside communication device
detection determination portion 502.
Subsequently, when the signal of the Short message is transmitted by using
the test signal wave 603 set to less than the lowest reception intensity, if the control
portion 103 confirms that the signal with the same contents as the test signal
instructed in the control portion is not detected in the reception portion 106, it is
determined that there is no problem with the reception intensity detection circuit 501
or the trackside communication device detection determination portion 502, while if
the control portion 103 confirms that the signal with the same contents is detected in
the reception portion 106, it is determined that there is a problem with the reception
intensity detection circuit 501 or the trackside communication device detection
determination portion 502.
In any case, when the Long message is used as the test signal, since the Long
message is directly inputted into the decoding circuit 115 by using the test signal
transmission path 111, if the message signal from the trackside communication
device 102 is detected in the trackside communication device detection
determination portion 502, immediate stop of the transmission, demodulation, and
decoding of the Long message test signal 401 is made possible. Thus, even if the
Long message test signal 401 collides with the Long message signal 304 from the
trackside communication device 102 when the Long message test signal 401 is
transmitted, the repeatedly sent Long message signal 304 can be received, and as a
result, high reliability of the on-board communication device 101 body can be kept
without missing the message signal from the trackside communication device 102 in
self-diagnosis.
(Embodiment 3)
Subsequently, by using FIG. 8, a third embodiment of the present invention will
be described. In this embodiment, the received message from the trackside
communication device 102 is decoded, and a stale failure of a buffer register 701
which temporarily stores the decoded message signal is detected.
As illustrated in FIG. 8, the reception portion 106 is provided with the buffer
register 701 which temporarily stores the decoded message of the trackside
communication device 102 in an output stage of the decoding circuit 504 in some
cases. If a stale failure (non-writable but readable) occurs in a state in which
message data of the normal trackside communication device 102 is stored in this
buffer register 701, the control portion 103 executes processing by considering that
the message of the normal trackside communication device 102 has been extracted
though the message data has not been rewritten correctly. Thus, in order to detect
a stale failure of the buffer register 701, a plurality of test messages with different
contents are prepared for each of the Long message and the Short message in the
diagnosis of the reception portion 106 of the on-board communication device 101.
Then, regarding the Long message, the test messages with different contents are
sequentially transmitted to the decoding circuit 504 through the test signal
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transmission path 111 without via the antenna 110. In the control portion 103, if
each of the messages transmitted from the test signal generation circuit is confirmed,
it is determined that the buffer register 701 is normal, and if not, it is determined that
the buffer register 701 has a stale failure.
Regarding the Short message, too, substantially similarly, the test messages
with different contents are sequentially transmitted to the on-board reception antenna
107 via the antenna 110. In the control portion 103, if each of the messages
transmitted from the test signal generation circuit is confirmed, it is determined that
the buffer register 701 is normal and if not, it is determined that the buffer register
701 has a stale failure.
Moreover, in the above-described embodiments, a procedure in which the
different test messages, that is, the Long message and the Short message are
continuously transmitted, respectively, is described, but if the buffer register 701 can
store only one message, presence of the stale failure of the buffer register 701 can
be confirmed by alternately transmitting the Long message and the Short message.
In any case, similarly to the case of the embodiment 2, if the Long message is
used as the test signal, the Long message is directly inputted into the decoding
circuit 115 by using the test signal transmission path 111 and thus, in the trackside
communication device detection determination portion 502, if the message signal
from the trackside communication device 102 is detected, immediate stop of
transmission, demodulation, and decoding of the Long message test signal 401 is
made possible. Thus, even if the Long message test signal 401 collides with the
Long message signal 304 from the trackside communication device 102 at
transmission of the Long message test signal 401, the repeatedly sent Long
message signal 304 can be received, and as a result, high reliability of the on-board
communication device 101 body can be kept without missing the message signal
from the trackside communication device 102 in self-diagnosis.
The present invention is not limited to the above-described embodiments 1, 2,
and 3 but includes various variations. Moreover, a part of the configuration of one of
the embodiments can be replaced with another embodiment configuration.
Moreover, the above-described embodiments are described so that the present
invention is easily understood, and are not necessarily limited to those provided with
all the described configurations.
For example, the type of the message or the configuration of the reception
portion can be changed as appropriate in accordance with purposes of use and
applications. Moreover, it is natural that the other configurations of the on-board
communication device and the trackside communication device can include various
variations depending on the type, size and the like of the mobile body.
Furthermore, the present invention is described such that the on-board
communication device outputs an electric power wave toward the trackside
communication device but to the contrary, it is natural that the present invention can
be applied to those performing wireless power feed by the electric power wave from
the trackside communication device to the mobile body communication device.
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Moreover, regarding signal lines and information lines described in the
drawings, those considered to be necessary for explanation are indicated and not all
the signal lines and information lines on the product are indicated. Actually, it may
be considered that almost all the configurations are connected to each other.

What is claimed is:
1. An on-board communication device provided on a mobile body, receiving a
message signal transmitted from a trackside communication device by an on-board
reception antenna, and processing the message signal received by the on-board
reception antenna by a demodulation circuit and a decoding circuit, comprising,
a test signal generation circuit for generating a test signal, a test signal
transmission antenna, and a trackside communication device detection determination
portion making detection determination of the trackside communication device,
wherein:
in a plurality of types of test signals generated in the test signal generation
circuit, a first signal with a long message length is configured to be inputted into the
decoding circuit from the test signal generation circuit via a test signal transmission
path;
in the plurality of types of test signals generated in the test signal generation
circuit, a second signal with a message length shorter than the first signal is
configured to be inputted into the demodulation circuit from the test signal generation
circuit via the test signal transmission antenna and the on-board reception antenna;
and
in the trackside communication device detection determination portion, when
the signal transmitted from the trackside communication device is detected,
demodulation, decoding, and transmission processing of the test signal are
configured to be stopped.
2. The on-board communication device according to claim 1, wherein
the on-board communication device is provided with a reception intensity
detection circuit for detecting reception intensity of the message signal sent from the
trackside communication device; and
a control portion is provided capable of checking normality of the reception
intensity detection circuit and the trackside communication device detection
determination portion by transmitting both the test signal at a detection reception
intensity threshold value or more of the message signal and the test signal less than
the threshold value generated by the test signal generation circuit to the reception
intensity detection circuit and the trackside communication device detection
determination portion.
3. The on-board communication device according to claim 1 or 2, further
comprising:
a control portion in which the test signal generation circuit generates a plurality
of the test signals with different contents for each type of a message length, transmits
the plurality of test signals with the different contents and has the test signals stored
in a buffer register provided on the on-board communication device, and can check
normality of the buffer register by checking that a storage result of the buffer register
is changed.