JP2000286760A - Coupler for mobile communication, mobile object and communication method for mobile object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit/receive a signal at a proper level even at any position on a line. SOLUTION: A coupler 11 is made of a metallic plate, the cross section of the coupler 11 is channel-shaped to surround a feeder (line) 12, and has a width (k) in an extension direction of the feeder 12. Since the coupler 11 is structured to surround the feeder 12, the coupler 11 is capacitively coupled with the feeder 12 to pick up a signal transmitted through the feeder 12 through the capacitive coupling and transmits a signal outputted from a communication unit to the feeder 12 through the capacitive coupling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupler used for communication of a mobile unit, a mobile unit, and a communication method of the mobile unit.

[0002]

2. Description of the Related Art An unmanned transport system for transporting parts and packages unattended in factories, warehouses, and the like has been introduced. In this unmanned transport system, as a method of receiving power for driving a moving body, there is a method of directly contacting a current collector with a power supply line and a method of receiving power from the power supply line in a non-contact manner. In the former method, both the power supply line and the current collector wear due to the contact between the power supply line and the current collector, so that maintenance is required. In addition, the problem that the contact generates dust and cannot be used in a clean room or the like. There is a point. Therefore, recently, a method of supplying power to a mobile body in a non-contact manner has been used.

[0003] In order to operate a mobile unit unmannedly, it is necessary to transmit a signal for controlling operation from the operation control unit to the mobile unit, and to transmit a signal from the mobile unit to the operation control unit to inform the operation control unit of the state of the mobile unit. There is. Normally, these signals are transmitted using a dedicated communication line. However, a method of transmitting a signal by using a power supply line for supplying power to a moving object and superimposing the signal on a current flowing through the power supply line has been considered. .

Here, a case will be described in which a signal is superimposed on a power supply line of a non-contact power supply system for supplying power to a mobile body in a non-contact manner and transmitted. FIG. 8 is an explanatory diagram of a case where signals are transmitted and received by a conventional induction coil type coupler. This non-contact power supply system includes a high-frequency power supply device for supplying high-frequency AC power, an operation control device for controlling the operation of the moving body, and a moving body.

Although not shown, the induction coil type coupler 81 is provided integrally with the moving body, and controls the operation of the moving body which is transmitted by being superimposed on the electric power supplied to the power supply line 82. The operation control signal is received by the coupler 81, or a signal indicating the state of the moving body is transmitted from the coupler 81 to the power supply line 82.

[0006]

However, since the induction coil type coupler has a relatively narrow signal detection range, the power supply line 8 is affected by interference of a signal reflected at the end of the power supply line 82 or the like.
2 has a problem that the signal level is lowered at a specific position, and the signal cannot be received normally.

In addition, when the transport path is long, there is a limit to the length of power that can be supplied from one high-frequency power supply to the power supply line. Therefore, the power supply line is divided into a plurality of power supply lines, and a high-frequency power supply is provided for each power supply line. The power is supplied to the moving body by using the power.
In this case, it is difficult to completely match the frequencies and phases of a plurality of high-frequency power supplies, so that the power receiving core simultaneously receives power with different frequencies and phases from two power supply lines connected to different high-frequency power supplies. In order to prevent this, the power supply lines are arranged at a certain distance or more.

FIG. 9 is an explanatory diagram of a reception level when a signal transmitted through a power supply line is received using an induction coil type coupler in a system in which the power supply line is divided. As a result of the moving body moving, as shown in FIG.
Enters a section in which no signal exists between the power supply line 92a and the power supply line 92b, the signal level is significantly reduced. As a result, the operation control signal transmitted from the operation control device cannot be normally received, and there is a problem that the operation of the moving body is hindered.

[0009] The object of the present invention is that any position on the track,
The purpose is to enable transmission and reception of an appropriate level signal. Another problem is that a signal transmission line is divided into a plurality of lines with different power sources, and even if the divided lines are arranged at a fixed interval, signals can be transmitted and received without interruption. That is.

[0010]

According to the first aspect of the present invention,
A mobile communication coupler for transmitting or receiving a signal transmitted through a line, made of a conductive material extending in a direction parallel to the line with a predetermined width, and extracting a signal transmitted through the line by capacitive coupling. Or a coupler for mobile communication for transmitting a signal to a line by capacitive coupling.

According to the present invention, since the coupler for extracting a signal by capacitive coupling is extended by a predetermined width in the direction parallel to the line, the signal level at a specific position on the line due to interference of a signal transmitted through the line. , The signal having the strength equal to or higher than a certain level can be transmitted and received in the entire coupler.

For example, the line is composed of two power supply lines for supplying power to the moving body in a non-contact manner, and a signal is transmitted from the coupler while being superimposed on the AC power supplied to the power supply line. According to a sixth aspect of the present invention, there is provided a coupler for mobile communication for transmitting and receiving a signal transmitted through a line, wherein a signal transmitted through the line is extracted by capacitive coupling or a signal is transmitted to the line by capacitive coupling. A first coupler which is arranged at a predetermined distance in a direction parallel to the line with respect to the first coupler, and extracts a signal transmitted through the line by capacitive coupling, or sends a signal to the line by capacitive coupling. And a second coupler.

According to the present invention, even if the signal level drops at a specific position on the line due to fading or the like, the first and second couplers are arranged at a predetermined distance, so that one of the couplers Even if the signal level is reduced, the signal level of the other coupler is equal to or higher than a certain level, so that a signal of an appropriate level can be transmitted and received by the entire coupler.

Further, when the line is divided into a plurality of lines having different power supplies, the first coupler and the second coupler are arranged at a distance longer than the gap of the divided lines, thereby moving the line. Even if the body moves and enters a gap where one coupler cannot receive a signal between the lines, the other coupler can receive the signal transmitted on the line, so the overall coupler Can transmit and receive signals at a certain level or higher in all sections of the track. Thus, a signal of an appropriate level can be transmitted and received at any position on the track.

According to a tenth aspect of the present invention, there is provided a mobile unit for performing communication using a line, wherein the first and second couplers are arranged at a predetermined distance in a direction parallel to the line, and the first and second couplers are arranged at a predetermined distance. Phase adjusting means for matching the phases of the signals received by the first and second couplers and the other of the first and second couplers, the phase of which is adjusted by the phase adjusting means. Signal and the transmission signal
And a combining / distributing means for distributing to the second coupler.

According to the present invention, even when the signal level decreases at a specific position on the line due to signal interference or the like, or when the phases of the received signals are reversed, the signal phases of the two couplers match. Then, by combining them, a signal of an appropriate level can be received.

According to a fifteenth aspect of the present invention, there is provided a moving body for performing communication using a line, wherein the first and second couplers are arranged at a predetermined distance in a direction parallel to the line, and the first and second couplers are provided. Comparing means for comparing the received signal level of the second coupler, selecting means for selecting a coupler having a higher received signal level based on the comparison result of the comparing means, and transmission and reception of signals by the coupler selected by the selecting means And communication means for performing the following.

According to the present invention, transmission and reception of a signal can be performed by selecting a coupler having a higher received signal level, so that reception or transmission of one of the couplers can be performed at the reflection of a signal or at a joint between lines. Even when the signal level decreases, the other coupler can receive or transmit a signal of an appropriate level.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, a case where the coupler for mobile communication according to the present invention is used for a mobile body of a non-contact power supply system will be described. Although not shown, the configuration of the contactless power supply system is such that a power supply line and a power supply device for supplying high-frequency power to the power supply line, and a control signal for controlling the operation of the moving body are superimposed on the power supplied to the power supply line. And an operation control device for sending out.

The structure of the coupler for mobile communication according to the first embodiment of the present invention will be described with reference to FIG. 1 on the premise of the above-described wireless power supply system. The coupler 11 for mobile communication of the first embodiment is made of a metal plate, and has a U-shaped cross section so as to surround a feeder line (line) 12.
It has a predetermined width k in the extension direction of the power supply line 12. The coupler 11 is connected to a communication device (not shown) of the mobile body,
The signal detected by the coupler 11 is sent to a communication device.

Since the coupler 11 has a structure surrounding the feeder line 12, it is capacitively coupled to the feeder line 11 and
2 can be extracted by capacitive coupling, and a signal output from the communication device can be transmitted to the feed line 12 by capacitive coupling.

In the first embodiment, since the coupler 11 for detecting a signal transmitted through the feed line 12 is extended by a predetermined width k in the extension direction of the feed line 12, the feed line 12 is subjected to fading or the like. Even if the signal level at the specific position decreases, the entire coupler 11 can transmit and receive a signal of a certain level or more. In addition, by increasing the width of the coupler 11, the signal receiving sensitivity and the transmission intensity can be improved.

In the first embodiment described above, the coupler 11 has a U-shape. However, the present invention is not limited to this, and a single metal plate or a feed line is provided so as to face the feed line 12. Two metal plates may be arranged so as to sandwich 12.

Next, the first and second two couplers 21, 22 will be described.
A second embodiment of the present invention in which a signal is transmitted and received using the second embodiment will be described with reference to FIG. In the second embodiment as well, a signal for controlling the operation of the mobile unit is superimposed on the power supply line 23 for supplying power to the mobile unit and transmitted. The power supply line 23 of the second embodiment includes a plurality of divided power supply lines 23a and 23b.
.., And a power supply line 2 (not shown)
Are connected to different high-frequency AC power supplies, respectively.

The first coupler 21 is a metal plate having a U-shaped cross section so as to surround the two feed lines 23 in the forward and return directions, and having a width k in the extension direction of the feed lines 23. And the output of the first combiner 21 is a two-divider / mixer 24
Is output to The second coupler 22 is also the first coupler 2
As in the case of 1, the cross section is formed in a U-shape so as to surround the two power supply lines 23, and is formed of a metal plate having a width k in the extension direction of the power supply line 23. / Mixer 24. The second coupler 22 is arranged at a distance d from the first coupler 21. First
The distance d between the coupler 21 and the second coupler 22 is
The distance is set to be longer than the gap D between 3a and the power supply line 23b. This is so that even if one of the couplers enters the gap between the power supply line 23a and the power supply line 23b, the other coupler exists on the power supply line 23 and can detect a signal transmitted through the power supply line 23. To do that.

The two distributor / mixer 24 includes a first combiner 21
And the output signal of the second coupler 22 are mixed and output to the communication device, and the signal output from the communication device and composed of the position information of the moving object is distributed to the first and second couplers 21 and 22, 2
Output to 2.

In the second embodiment, the first and second couplers are arranged at a distance longer than the gap length D of the feeder line 23, and as a result of the movement of the moving body, one of the couplings is formed. Even if the device enters the section where the feeder line 23 does not exist, the signal transmitted through the feeder line 23 can be detected by the other coupler. The problem that hinders driving of the body does not occur.

In the second embodiment, first and second two couplers 21 and 22 are used, and the first and second couplers 21 and 22 are arranged in a direction parallel to the feeder line 23. Since the signal is extended with a constant width k, even if the first coupler 21 or the second coupler 22 comes to a position where the signal level becomes small due to fading or the like, a signal of a certain level or more is transmitted and received in the entire coupler. can do.

FIGS. 3A and 3B are diagrams showing examples of other shapes of the first and second couplers 21 and 22. FIG.
3A shows a coupler having a U-shaped cross section, and FIG. 3B shows a coupler having a V-shaped cross section. Note that the capacitive coupling type coupler may be formed of one conductive flat plate.

FIG. 4 shows a connection when the corners are cut off so that the couplers 21 and 22 do not contact the rail for guiding the traveling of the moving body when the traveling path of the moving body is curved. 3 shows the structure of the container 41.

Next, FIG. 5 shows a third embodiment of the present invention in which a signal of an appropriate level can be transmitted and received by using an induction coil type coupler when the power supply line is divided into a plurality of parts. It will be described with reference to FIG.

This embodiment comprises a plurality of divided power supply lines 53a, 53b,...
Are connected to different high-frequency AC power supplies. In the third embodiment, an induction coil type first coupler 51 is arranged at a distance d from a second coupler 52. The outputs of the first combiner 51 and the second combiner 52 are output to the two distributor / mixer 54.

The two distributor / mixer 54 mixes the output signals of the first and second couplers 51 and 52 and outputs the mixed signal to the communication device, and also combines the signal output from the communication device with the first and second connection signals. To the containers 51 and 52.

The distance d between the first coupler 51 and the second coupler 52 is set to be longer than the gap D between the feed line 53a and the feed line 53b. This is because even if one of the couplers enters the gap D between the power supply line 53a and the power supply line 53b, the other coupler exists on the power supply line 53, and the signal transmitted through the power supply line 53 is transmitted. This is to enable detection by either coupler.

According to the third embodiment, by disposing the two couplers of the induction coil type at a distance longer than the gap length D of the feed line 53, the moving body moves, and as a result, the feed line Even if one of the couplers enters the gap of 53, the other coupler receives a signal transmitted on the feed line 53,
Alternatively, a signal can be transmitted.

Further, since there are two couplers, the first coupler 51 and the second coupler, even if the signal level is lowered at a specific position of the feeder line 53 due to fading or the like, the entire coupler is appropriate. Level signals can be transmitted and received.

Next, a fourth embodiment of the present invention in which the phases of the received signals of the two couplers are matched to synthesize the signals will be described with reference to FIG. The received signals of the first and second couplers 61 and 62 are
The signals are tuned and received at 3, 64, and demodulated by demodulation circuits 65, 66. Further, the phase of the signal received by the first coupler 61 is adjusted by the phase adjustment circuit 67, and then the
Is output to The first and second couplers 61 and 62 may be the above-described capacitive coupling couplers or may be inductive coupling couplers.

Output of phase adjustment circuit 67 and demodulation circuit 66
Is input to the phase comparison circuit 69. The phase comparison circuit 69 compares the phases of the two signals, and controls the amount of phase adjustment in the phase adjustment circuit 67 based on the comparison result.

That is, the phase of the output signal of the phase adjustment circuit 67 for adjusting the phase of the reception signal of the first coupler 61,
By controlling the amount of phase adjustment in the phase adjustment circuit 67 so that the phases of the reception signals of the second coupler 62 match, and combining the two signals with the same phase, any position on the line is equal to or higher than a certain level. Can be received. Note that the position of the phase adjustment circuit 67 is not limited to the stage following the demodulation circuit 65, and may be arranged before the RF circuit 63 or the demodulation circuit 65.

According to the fourth embodiment, even when the received signal phases of the two couplers do not match due to the position of the moving body, the reflection of the signal on the line, etc., the signal phases are matched and the two signals are combined. By doing so, it is possible to always receive a signal of an appropriate level.

Next, a fifth embodiment of the present invention in which a coupler is switched according to a signal reception level will be described with reference to FIG. The coupler switching circuit 73 is a circuit for switching between the first coupler 71 and the second coupler 72, and includes a switching signal a output from the communication control circuit 74.
The receiving coupler is switched according to the following. Couplers 71 and 72
May be a capacitive coupling type coupler or an inductive coupling type coupler.

The output of the coupler switching circuit 73 is RF / I
The signal is input to the F circuit 75 and converted from the radio signal to the intermediate frequency signal in the RF / IF circuit 75. RF / I
The F circuit 75 detects the signal level of the received signal and outputs the detection result to the communication control circuit 74.

The output of the RF / IF circuit 75 is a demodulation circuit 76
Is demodulated to a signal of the original frequency, and the demodulated signal is output via the communication control circuit 74. In the mobile communication system of this embodiment, the ground station grants the data transmission right to the mobile by polling, the mobile that has acquired the data transmission right transmits the data, and the ground station receives the data received from the mobile. Is returned to the mobile as it is. Then, the mobile unit that transmitted the data, depending on whether the data transmitted by itself is sent back from the ground station,
Checking whether data was successfully transmitted to the ground station.

Therefore, when transmitting data, if the data sent back from the ground station cannot be received, the signal level of the transmission signal is reduced due to the position of the moving body and the like, and it is determined that the ground station could not receive the data. Then, the data can be reliably transmitted by switching the coupler and transmitting the data.

According to the fifth embodiment, a specific position, that is, a branching portion, a merging portion, a turntable portion for changing the direction of a line, a joint at a joint of a line when the line is loop-shaped, etc. Even when the signal level decreases or the signal level decreases due to signal reflection or the like, it is possible to always receive an appropriate level signal by switching the two couplers and receiving the signal.

In the above-described embodiment, a case has been described in which a signal is superimposed on a power supply line for supplying power to a mobile body and transmitted. However, the present invention is not limited to this and can be applied to communication systems other than superimposed communication.

[0047]

According to the present invention, even if there is a position where the signal level is reduced on the line, the use of the capacitive coupling type coupler extending at a predetermined width in the line direction enables the proper level of the entire coupler. Can be transmitted and received. Further, by arranging the first coupler and the second coupler at a predetermined distance, for example, at least the length of the gap between the lines when the lines are divided, one of the couplers enters the gap. Even if the signal cannot be transmitted and received, the signal can be transmitted and received by the other coupler. Further, by switching the plurality of couplers in accordance with the signal reception level, even when the signal reception level fluctuates due to the position of the moving body, a signal of an appropriate level can be transmitted and received.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a coupler according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a structure of a coupler according to a second embodiment.

FIGS. 3A and 3B are diagrams showing other shapes of the coupler. FIGS.

FIG. 4 is a diagram illustrating a shape of a coupler in which a corner portion is notched and a transport path.

FIG. 5 is a diagram illustrating a structure of a coupler according to a third embodiment.

FIG. 6 is a block diagram of a communication circuit according to a fourth embodiment.

FIG. 7 is a block diagram of a communication circuit according to a fifth embodiment.

FIG. 8 is an explanatory diagram of a case where signals are transmitted and received by a conventional induction coil type coupler.

FIG. 9 is an explanatory diagram of a reception level when a signal is received using a conventional induction coil type coupler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Coupling device 12, 23, 53 Feeding line 21, 51 1st coupling device 22, 52 2nd coupling device 24, 54 2 distribution / mixer 67 Phase adjustment circuit 68 Combining circuit 69 Phase comparison circuit 73 Coupler switching circuit

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 21, 2000 (200.3.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

The method according to claim 1] feed line for feeding the power in a non-contact to the mobile
Mobile communication for transmitting or receiving transmitted signals
A credit coupler, comprising a conductive material extending at a predetermined width in a direction parallel to the power supply line.
And receives a signal transmitted through the power supply line by capacitive coupling.
Or sends a signal to the feeder line by capacitive coupling
A first coupler, and a conductive material extending at a predetermined width in a direction parallel to the power supply line.
And a direction parallel to the feeder line with respect to the first coupler.
The gap between adjacent feeders connected to different power sources.
Located a longer distance than the
Or receive signals by capacitive coupling
And a second coupler for transmitting to the feeder line.
And a coupler for mobile communication.

2. The first and second couplers are connected to the power supply line.
It consists of a metal plate that is placed opposite to
The coupler for mobile communication according to claim 1, wherein

3. The signal received by said first and second combiners.
Phase adjusting means for matching the phases of the signals to be adjusted, and the first or second phase adjusted by the phase adjusting means.
One of the received signals of the first and second couplers.
Combines the other received signal of the combiner with the transmitted signal.
Combining / distributing the signal to the first and second combiners
The moving body according to claim 1, further comprising:
Communication coupler.

4. A reception signal of the first and second coupler level
Comparing means for comparing the Le, large received signal level based on the comparison result of the comparing means
Selecting means for selecting a threshold coupler, and transmitting and receiving signals by the coupler selected by the selecting means.
Communication means for performing communication.
The coupler for mobile communication according to claim 1.

5. A power supply line for supplying power to a moving body in a non-contact manner.
Mobile communication for transmitting or receiving transmitted signals
A credit coupler, which receives a signal transmitted through the power supply line by magnetic coupling,
Or a first for transmitting a signal to the feeder line by magnetic coupling.
And couplers, in a direction parallel with the feed line to said first coupler, different
Than the gap between adjacent power lines connected to different power sources
A signal that is located a long distance away and is transmitted over the feeder
Is received by magnetic coupling, or the signal is received by magnetic coupling.
And a second coupler for transmitting to the feeder line.
Mobile communication coupler.

6. A power supply line for supplying power to a moving body in a non-contact manner.
A mobile communication method that transmits or receives transmitted signals
A method, using a first coupler, volumes of signal transmitted through the feed line
Receive or signal by quantitative or electromagnetic coupling.
The signal is transmitted to the feed line by a quantitative coupling or a magnetic coupling , and is different from the first coupler in a direction parallel to the feed line.
Than the gap between adjacent power lines connected to different power sources
With a second coupler located a long distance apart,
The signal transmitted through the feeder line is
Or receive signals by capacitive or magnetic coupling.
Mobile communication method characterized by transmitting to the feeder line
Law.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuhiro Mabuchi 2-1-1, Toyota-cho, Kariya-shi, Aichi F-term in Toyota Industries Corporation (reference) 5H161 AA07 BB02 CC13 DD11 DD41 5K012 AA01 AA03 AB04 AB06 AC05 AC06 AC08 AC10 AE13 5K046 AA01 CC14 HH77 YY04 5K059 CC02 CC03 CC09 DD02 DD07 DD31 DD37 EE03

Claims (17)

[Claims] 1. A coupler for mobile communication for transmitting or receiving a signal transmitted through a line, comprising a conductive material extending at a predetermined width in a direction parallel to the line. A mobile communication coupler for extracting a signal through capacitive coupling or transmitting a signal to the line by capacitive coupling. 2. The transmission line according to claim 1, wherein the line comprises two power supply lines for supplying power to the moving body, and the signal is transmitted by being superimposed on AC power supplied to the power supply line. Mobile communication coupler. 3. The coupler for mobile communication according to claim 1, wherein the coupler for mobile communication comprises a metal plate arranged to face the line so as to sandwich the line. 4. The coupler for mobile communication according to claim 1, wherein the coupler for mobile communication comprises a metal plate arranged so as to surround the line. 5. The mobile communication coupler according to claim 4, wherein the line comprises two parallel lines, and the coupler for mobile communication comprises two couplers arranged so as to surround each line.
The coupler for mobile communication according to claim 1. 6. A first coupler for extracting a signal transmitted through a line by capacitive coupling or transmitting a signal to the line by capacitive coupling, and a first coupler coupled in a direction parallel to the line with respect to the first coupler. A second coupler arranged at a predetermined distance and taking out a signal transmitted through the line by capacitive coupling or transmitting a signal to the line by capacitive coupling. . 7. The line comprises a plurality of lines having different power supplies, and the second coupler is arranged at a predetermined distance longer than a gap between the lines adjacent to the first coupler. 7. The coupler for mobile communication according to claim 6, wherein: 8. The power supply for supplying electric power to the moving body.
8. The coupler for mobile communication according to claim 6, wherein the power transmission line is composed of three power supply lines, and the signal is transmitted while being superimposed on AC power supplied to the power supply line. 9. The coupler for mobile communication according to claim 6, wherein said first and second couplers are made of a metal plate arranged so as to surround said line. 10. A mobile body performing communication using a line, comprising: a first and a second coupler arranged at a predetermined distance in a direction parallel to the line; and a first and a second coupler. Phase adjusting means for matching the phase of a received signal; and the first or second phase adjusted by the phase adjusting means
And a combining / distributing means for combining the received signal of the first and second combiners with the other received signal of the first or second combiner and distributing the transmission signal to the first and second combiners. A mobile object characterized by the fact that: 11. The line comprises a plurality of lines having different power supplies, and the first coupler extracts a signal transmitted through the line by capacitive coupling or sends a signal to the line by capacitive coupling. The second coupler is a capacitive coupling coupler that extracts a signal transmitted through the line by capacitive coupling or sends a signal to the line by capacitive coupling. The moving body according to claim 10, wherein the two couplers are arranged at a predetermined distance longer than a gap between the adjacent lines with respect to the first coupler. 12. The power transmission line according to claim 12, wherein the transmission line includes two power supply lines for supplying power to the moving body, and the signal is transmitted by being superimposed on AC power supplied to the power supply line. 12. The moving object according to 10 or 11. 13. The moving body according to claim 10, wherein said first and second couplers are made of a metal plate arranged so as to surround said line. 14. A mobile unit performing communication using a line, wherein a signal transmitted through the line is extracted by electromagnetic induction.
Or a first coupler that sends a signal to the line by electromagnetic induction, and is disposed at a predetermined distance in the line direction with respect to the first coupler, and takes out a signal transmitted through the line by electromagnetic induction, Alternatively, a second coupler for transmitting a signal to the line by electromagnetic induction, phase adjusting means for matching the phases of the signals received by the first and second couplers, and a phase adjusted by the phase adjusting means Combining the received signal of the first or second coupler and the other received signal of the first or second coupler, and distributing a transmission signal to the first and second couplers / A distributing means. 15. A mobile unit that performs communication using a line, comprising: a first and a second coupler arranged at a predetermined distance in a direction parallel to the line, and the first and the second couplings. Comparing means for comparing the received signal levels of the devices, selecting means for selecting a coupler having a large received signal level based on the comparison result of the comparing means, and transmitting and receiving signals by the coupler selected by the selecting means A mobile object comprising: communication means. 16. The first and second couplers are made of a conductive material extending a predetermined width in a direction parallel to the line, and take out a signal transmitted through the line by capacitive coupling, and couple the signal by capacitive coupling. 16. The moving body according to claim 15, wherein the moving object is transmitted to the track by the following. 17. A communication method for a mobile unit performing communication using a line, comprising: comparing received signal levels of first and second couplers arranged at a predetermined distance in a direction parallel to the line; A communication method for a mobile object, comprising selecting a coupler having a high received signal level and transmitting / receiving a signal.