JP4221595B2 - Ground-mobile communication system - Google Patents

Description

  The present invention relates to a communication system between a moving body that travels on a certain travel route, for example, a traveling body for transportation in a transportation facility and a ground station.

Based on control signals from the ground-side host computer, it controls the start, shift, stop, etc. of the transport traveling body that travels on a certain travel route, and controls various work devices mounted on the transport traveling body. As a communication system in the case of transmitting a periodic notification of the current position, a reception confirmation notification of the control signal, a notification of completion of instructed control, etc. from the transport traveling body to the ground side host computer, for example, Patent Document 1 discloses As described above, it is connected to the ground-side host computer via a leaky coaxial communication line that is stretched along the travel route of the transport traveling body and has one end connected to the ground station and an antenna provided on the transport traveling body. It is known that communication is performed between a received ground station and a mobile station on the transport traveling body.
Japanese Patent Laid-Open No. 2001-216022

  Thus, in this type of ground-mobile communication system, the total length of the communication line is determined by the communicable distance from the ground station. In other words, the signal quality (including strength) leaked from the communication line deteriorates as the distance from the ground station that is the transmission source is deteriorated. If the length of the travel path of a mobile body (such as a transport traveling body) over which the communication line is stretched exceeds the communicable distance, the communication line should be extended via a repeater station. It has been known.

  Thus, in a conventional system using a repeater station, if the same distance is used on the primary side and the secondary side of the repeater station to extend the communication distance, radio interference occurs between the primary side and the secondary side of the repeater station. However, communication becomes unstable near this repeater station, and in the worst case, communication becomes impossible. Of course, it is conceivable to communicate at different signal frequencies on the primary side and secondary side of the repeater station, but it is necessary to switch the transmission / reception frequency on the mobile station side, making the configuration of each station complicated, and the overall system as a whole This can lead to a significant cost increase.

The object of the present invention is to provide a terrestrial / mobile communication system capable of solving the conventional problems as described above, and the present invention according to claim 1 is an embodiment described later. When indicated with a reference numeral, the mobile unit is provided with the leaky coaxial communication line 3 extending along the travel path 2 of the mobile unit (conveying mobile unit 1) and having one end connected to the ground station 7 and the mobile unit. and a ground-mobile communication system for performing communication between the antenna 4 and to the ground station 7 via the mobile station 5 on the movable body, earth station 7A one running path 2 to each other, Covered by a plurality of communication lines 3A and 3B provided with 7B, the ground stations 7A and 7B connected to each of the communication lines 3A and 3B synchronize and transmit signals of the same frequency, and two adjacent to each other Mobile station in a specific section A including the ends of the communication lines 3A and 3B Signal, the mobile station 5 the two communication lines 3A, each earth station 7A to 3B, the ground-mobile communication systems to transmit alternately at the same frequency from 7B, which is located within said specific section A for The mobile station specifying means specifies the mobile station 5 located in the specific section A based on the number of transmission retries from the ground stations 7A and 7B due to a transmission failure with respect to the mobile station 5. Then, subsequent transmission retries to the specified mobile station 5 are performed at the same frequency from the ground stations 7A and 7B with respect to the two communication lines 3A and 3B whose ends are located in the specific section A. It is configured to perform alternately .

That is, in this type of communication system, when a control signal is transmitted from a ground station to a specific mobile station (specific mobile body), a reception confirmation signal is transmitted from the specific mobile station to the ground station, and this reception confirmation is performed. When the signal is not within a predetermined time, a transmission retry is performed to retransmit the same signal. However, in the present invention according to claim 1 , the ground station 7A associated with a transmission failure with respect to the mobile station 5 is configured. , 7B, the mobile station 5 in the specific section A is specified based on the number of transmission retries .

Further, as a method of specifying the mobile station 5 in the specific section A, the current position detection means 31 is provided in the moving body (conveyance traveling body 1) as in the present invention according to claim 2, and this current position is detected. By comparing the current position value detected by the position detecting means 31 with the set position value set corresponding to the specific section A, the position within the specific section A is determined on the moving body (conveying traveling body 1) side. In addition to the method for determining whether or not to detect, and as in the third aspect of the present invention, the detected portions 37 and 38 are disposed corresponding to the specific section A on the traveling path 2 side of the moving body. Sensors 39 and 40 for detecting the detection units 37 and 38 are provided in the moving body (conveying traveling body 1), and the detection of the detected parts 37 and 38 by the sensors 39 and 40 causes the moving body to be within the specific section A. Adopting a method to determine whether the position is It can be.

  According to the communication system of the transportation facility according to the present invention having the above-described configuration, since one traveling route is covered with a plurality of communication lines each having a ground station, the communication line can be extended without using a repeater station. However, in the vicinity of the adjacent end of each communication line where signals of the same frequency are output in synchronization, radio wave interference occurs between the two communication lines, and communication failure may occur. However, in the present invention, signals for mobile stations of mobile units in a specific section including the ends of two communication lines adjacent to each other are alternately transmitted from the respective ground stations to the two communication lines at the same frequency. Therefore, even in this specific section, that is, a section where there is a possibility of communication failure, it is not necessary to cause radio wave interference between two adjacent communication lines.

  Therefore, unlike the conventional system using a repeater station that uses the same communication frequency on the primary side and the secondary side, communication in the vicinity where the ends of the two communication lines are adjacent to each other is not unstable. Thus, normal communication can be reliably performed over the entire length of each communication line. Of course, even when compared with the method of communicating with different signal frequencies on the primary side and secondary side of the repeater station, it is not necessary to switch the transmission / reception frequency, so the configuration of the software and hardware of each station becomes simple, Can be implemented inexpensively. In the system of the present invention, a transmission signal from each mobile station to the ground station is transmitted to only one communication line in a section where the mobile station is present, and the communication line is transmitted via only the one communication line. Since it can be transmitted directly to the ground station connected to the same station, it can be performed satisfactorily without any trouble as in the conventional system consisting of only one communication line having a communicable distance length connected to one ground station. Can do.

Moreover, according to the configuration of the present invention as set forth in claim 1, since the mobile body (transporting traveling body) actually enters the specific section (communication failure section), communication from the ground station to the mobile station is normal. In response to the transmission retry from the ground station to the mobile station being performed, the mobile unit that has entered the specific section is identified, and subsequent transmissions to the identified mobile station are performed. As described in claim 1, since the retry is performed alternately at the same frequency from each ground station for the two communication lines whose ends are located in the specific section, the specific section ( There is no need to add special hardware or the like as means for identifying a mobile body that has entered a communication failure section), and the present invention is implemented at low cost by utilizing a conventional transmission retry system provided in this type of communication system. Can Kill.

In addition, according to the configuration of the present invention as set forth in claim 2 or 3, it is not after the transmission retry from the ground station to the mobile station is executed, but enters or enters the specific section (communication section). Since the mobile station can be specified, the length of the specific section is set to be appropriately longer than the communication failure section in which transmission retry from the ground station to the mobile station is actually executed. of from the ground station to almost no execution of transmission retries to the mobile station, but it is possible to help to eliminate the time delay of the control, according in particular to the configuration of the present invention according to claim 2, mobile A set position value corresponding to the position corresponding to the specific section is set in advance by learning or the like without arranging a special detected portion indicating the position corresponding to the specific section on the body travel route side. Just on the moving body side Wherein it is possible to detect when it reaches the position corresponding to the specific section, Easily accommodates such changes in the travel path layout of the moving body, also, according to the configuration of the present invention according to claim 3, the mobile Can be accurately checked by a simple and inexpensive configuration that does not require special control when the position reaches the position corresponding to the specific section.

  A specific embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a transporting traveling body as a moving body, and a leakage coaxial communication line 3 is stretched on the traveling path 2 thereof. Has been. In the figure, two transporting traveling bodies 1 are illustrated, but actually, a large number of transporting traveling bodies 1 are arranged on the same traveling path 2 and different identification numbers ( ID) is assigned. Each transport traveling body 1 is provided with a transmission / reception antenna 4 between the communication line 3 and a mobile station 5 connected to the transmission / reception antenna 4. The communication line 3 is composed of two communication lines 3A and 3B having a length that divides the entire length of the travel path 2 into two, and a host computer that controls the transport traveling body 1 is provided at one end of each of the communication lines 3A and 3B. 6 are connected to ground stations 7A and 7B for sending control commands for each transport traveling body 1 to the communication lines 3A and 3B. Terminating resistor devices 8A and 8B are connected to the other ends of the communication lines 3A and 3B. Has been. The two communication lines 3A and 3B are arranged so that the end 3a to which the ground stations 7A and 7B are connected and the end 3b to which the terminating resistor devices 8A and 8B are connected are adjacent to each other.

  The ground stations 7A and 7B transmit a signal for the mobile station having the frequency f1 and receive a signal for the ground station having the frequency f2, and the mobile station 5 on each carrier 1 is connected to the communication line 3A or 3B is configured to receive a signal for the mobile station having the frequency f1 and transmit a signal for the ground station having the frequency f2.

  More specifically, as shown in FIG. 2, the ground stations 7A and 7B have the same configuration, and are composed of an interface board 9 and a ground station modem 10. The interface board 9 includes a communication interface unit 11, a transmission terminal. Side and reception side digital filter units 12 and 14, a transmission side encoding unit 13, a reception side re-encoding unit 15, and the like. The ground station modem 10 includes a transmission modulation unit 16 and a reception demodulation unit 17. And are provided.

  The mobile station 5 on the transport traveling body 1 includes an interface board 18 and a mobile station modem 19. The interface board 18 includes a communication interface unit 20, transmission side and reception side digital filter units 21, 23, A transmission side encoding unit 22 and a reception side re-encoding unit 24 are provided, and the mobile station modem 19 is provided with a transmission modulation unit 25 and a reception demodulation unit 26, and a communication interface on the interface board 18. The unit 20 exchanges signals with a control controller 27 that controls a control target such as a travel drive device provided in the transport traveling body 1.

  According to the above configuration, when the control command is transmitted from the host computer 6 to the specific transport traveling body 1 on the travel route 2, the identification number (ID) that identifies the transport traveling body 1 to be controlled is set. The signal for the mobile station is input to both the ground stations 7A and 7B at the same time, processed by the digital filter unit 12 and the encoding unit 13 via the communication interface unit 11 of each ground station 7A and 7B, and the modem for the ground station. 10 modulation unit 16 converts the signal to a mobile station signal having a carrier frequency of f1 at a predetermined level (signal strength), synchronized with communication line 3A from ground station 7A and communication line 3B from ground station 7B. Is output.

  Thus, when the conveyance traveling body 1 to be controlled is in the area corresponding to the communication line 3A, the antenna 4 is located in the area corresponding to the communication line 3B from the communication line 3A. At this time, a signal for the mobile station having the frequency f1 is received from the communication line 3B via the antenna 4 respectively. The received signal is the demodulator 26 of the mobile station modem 19 of the mobile station 5, the interface board. 18 is processed by the digital filter unit 23 and the re-encoding unit 24, and mixed noise and signal distortion are removed and restored to the same quality as when output from the ground station 7A or 7B. It is output and predetermined control is performed.

  On the other hand, from the mobile station 5 on the transport traveling body 1, a reception confirmation signal for the signal for the mobile station having the frequency f1, a confirmation signal for starting and ending control based on the signal for the mobile station, a current position report signal, etc. Is transmitted to the host computer 6. That is, the signal for the ground station output from the control controller 27 is processed by the digital filter unit 21 and the encoding unit 22 via the communication interface unit 20, and is transmitted to a predetermined level by the modulation unit 25 of the mobile station modem 19. When the carrier frequency is converted into a signal for a mobile station having a carrier frequency of f2 by (signal strength) and the carrier traveling body 1 is in an area corresponding to the communication line 3A, the antenna is connected to the communication line 3A. When 4 is in the area corresponding to the communication line 3B, it is output to the communication line 3B via the antenna 4 and transmitted to the ground station 7A or 7B via the communication line 3A or communication line 3B. After being demodulated by the demodulating unit 17 of the ground station modem 10 of the ground station 7A or 7B and processed by the digital filter unit 14 and the re-encoding unit 15, mixed noise and signal distortion are removed. The data is input to the host computer 6 via the communication interface unit 11.

  In the above communication system, signals for mobile stations having the same frequency are output from both ground stations 7A and 7B in synchronization with the communication line 3A and the communication line 3B. Therefore, as shown in FIG. In a specific section A having a certain length including the ends adjacent to each other of the lines 3A and 3B, radio wave interference occurs between the communication lines 3A and 3B, and the frequency f1 of the signal for the mobile station greatly fluctuates, and the communication line 3A Alternatively, there is a case where the transmission of the signal for the mobile station from 3B to the transport traveling body 1 (mobile station 5) in the specific section A is not normally performed. In order to solve this problem, in the present invention, signals for the mobile station for the transport traveling body 1 (mobile station 5) located in the specific section A are alternately transmitted from the ground stations 7A and 7B to the communication lines 3A and 3B. So as not to cause radio wave interference between the communication lines 3A and 3B.

  Specifically, in this type of communication system, when a signal for a mobile station is transmitted from a ground station to a specific mobile station, reception confirmation from the specific mobile station that has received the signal for the mobile station to the ground station is confirmed. The signal is transmitted back, and when the reception confirmation signal is received by the ground station within a certain time, the transmission of the signal for the mobile station to the specific mobile station is completed. When reception is not possible, the same mobile station signal is retransmitted (transmission retry). If the transmission is not completed even after a predetermined number of transmission retries, another emergency measure is taken as an inability to communicate. Accordingly, when a signal for the mobile station is transmitted to the transport traveling body 1 (mobile station 5) located in the specific section A, the transport traveling body 1 (mobile station 5) moves due to radio wave interference. When the signal for the station cannot be normally received, the transmission retry is automatically executed from the ground stations 7A and 7B. However, the host computer 6 sends the mobile station 5 ( A processing unit 28 for specifying the transport traveling body 1) and a processing unit 29 for executing transmission from the ground stations 7A and 7B to the specified mobile station 5 alternately are provided. After the transmission retry number discriminating unit 30 of the mobile station specifying unit 28 determines that the number of transmission retries has reached a set number (for example, 2 times), the alternate transmission execution unit 29 for the specific mobile station performs transmission retry on the ground. Station 7A To be executed alternately from 7B.

  As a result of the control signal transmitted from the host computer 6 to the specific transport traveling body 1 that has entered the specific section A by the above processing, if a transmission retry is executed due to communication failure due to radio wave interference, After the number of transmission retries reaches the set number of times, a steady transmission system, that is, a steady transmission system that synchronously outputs signals for the same mobile station from both ground stations 7A and 7B to both communication lines 3A and 3B. Can be switched to an alternate transmission method in which the signals for the same mobile station are alternately output from both ground stations 7A and 7B to both communication lines 3A and 3B, so that the same frequency transmitted to both communication lines 3A and 3B can be obtained. In the specific section A, the antenna 4 corresponds to the communication line 3A in the specific section A of the specific transport traveling body 1 that has entered the specific section A without interfering with the signals for the mobile stations. From the communication line 3A when in the location, when the antenna 4 to the communication line 3B is the corresponding position can be from the communication line 3B, which normally receives the mobile station's signal addressed to the own vehicle.

  The method of specifying the transport traveling body 1 (mobile station 5) that has entered the specific section A is not limited to the method of using the number of transmission retries. For example, as shown in FIG. 3, positions P1 and P2 that are slightly separated from both ends of the specific section A where the occurrence of communication failure is expected or slightly outside both ends of the specific section A are set. Is equipped with a current position detection device 31 for detecting the current position on the travel route 2. The current position detection device 31 includes, for example, a pulse encoder 33, a calculation unit 34, and a comparison unit 35 that are linked to a wheel driven by a travel drive motor 32, an intermediate rotation shaft in a transmission mechanism between the motor 32 and the wheel, or the like. , And a logical operation unit 36.

  The calculation unit 34 adds the output pulse of the pulse encoder 33 during forward travel with the reference position set on the travel route 2 as the zero reset origin and subtracts it during reverse travel to output the current position value. The unit 35 obtains and sets in advance a position value output from the calculation unit 34 when the antenna 4 of the transport traveling body 1 is positioned at positions P1 and P2 corresponding to both ends of the specific section A by learning work or the like. The set position value thus set is compared with the current position value output from the calculation unit 34. The logical operation unit 36 is configured such that the transport traveling body 1 (antenna 4) traveling forward corresponds to the entrance of the specific section A based on the comparison operation result of the comparison unit 35 and the traveling direction information of the transport traveling body 1 at that time. Specified when it is in the section from the position P2 to the exit equivalent position P1, and when the transport traveling body 1 (antenna 4) traveling backward is in the section from the entrance equivalent position P1 to the exit equivalent position P2 of the specific section A A section presence signal is output.

  This specific section presence signal is combined with the vehicle identification number (ID) and is output from the mobile station 5 to the communication line 3A or 3B to which the antenna 4 corresponds at that time, and the communication line 3A or 3B and the ground station 7A. Alternatively, the transport traveling body 1 (mobile station) transmitted to the host computer 6 via 7B and entering the specific section A on the host computer 6 side can be determined. Therefore, when a signal for a mobile station is transmitted to the carrier 1 for transportation that has entered the specific section A (mobile station), communication is performed from the ground stations 7A and 7B by the alternate transmission method from the beginning instead of the steady transmission method. The signals are alternately transmitted to the lines 3A and 3B.

  In addition, the structure for notifying the host computer 6 side that the own vehicle has entered the specific section A from the mobile station 5 side on the transport traveling body 1 is not limited to that shown in FIG. For example, as shown in FIG. 4, to-be-detected parts 37 and 38 are arranged on the travel path 2 side of the transport traveling body 1 so as to correspond to both end equivalent positions P1 and P2 of the specific section A in FIG. Sensors 39 and 40 that detect the detected portions 37 and 38 when the antenna 4 is located at the positions P1 and P2 corresponding to both ends of the specific section A are attached to the traveling body 1 side. When a signal is input to the logical operation unit 36 and the traveling vehicle 1 (mobile station 5) enters the specific section A, a specific section presence signal is output to the mobile station 5 in the same manner as described above. The specific section presence signal can be combined with the vehicle identification number (ID) and output from the mobile station 5 to the corresponding communication line 3A or 3B.

  1 illustrates a layout in which the endless continuous travel route 2 is covered by the two communication lines 3A and 3B. In this layout, the travel direction of the transport traveling body 1 is clockwise or It can also be used so as to be limited to any one of the counterclockwise directions. Moreover, it is possible to adopt a configuration in which the travel path is not continuous in an endless manner and the transport traveling body 1 reciprocates. Further, it is possible to cover one traveling route with three or more communication lines each connected to an independent ground station. In this case, since there are three or more specific sections A, the specific section A into which the transport traveling body 1 (mobile station 5) has entered is the specific section A, that is, switching to alternate transmission 2 A means for specifying the book communication line is required.

It is a block diagram explaining the structure of the whole system. It is a block diagram explaining the structure of a ground station and a conveyance traveling body (moving body). It is a block diagram explaining the structure for switching from a regular transmission system to an alternating transmission system. It is a block diagram explaining the other structure for switching from a regular transmission system to an alternating transmission system.

Explanation of symbols

1 Transport body (moving body)
2 Traveling path 3, 3A, 3B of the traveling body for conveyance Leakage coaxial communication line 4 Transmitting / receiving antenna 5 Mobile station 6 Host computer 7A, 7B Ground station 8A, 8B Termination resistor device 9, 18 Interface board 10 Ground station modem 19 Movement Station modem 31 Current position detection device 37, 38 Detected part 39, 40 Sensor A Specific section P1, P2 Position corresponding to both ends of specific section

Claims (3)

Between the ground station and the mobile station on the mobile body via a leaky coaxial communication line stretched along the travel path of the mobile body and one end connected to the ground station and an antenna provided on the mobile body a ground-mobile communication system for performing communication between covers one traveling route a plurality of communication lines with the ground station to each other, the same from the ground station that is connected to each communication line The signal for the mobile station of the mobile unit in the specific section including the ends of the two communication lines adjacent to each other is transmitted from the ground station with respect to the two communication lines. In a terrestrial / mobile communication system that alternately transmits at a frequency, the communication system includes means for specifying a mobile station located in the specific section, and the mobile station specifying means transmits from the ground station due to a transmission failure to the mobile station. Based on the number of retries The mobile station located in the specific section is specified, and subsequent transmission retries to the specified mobile station are performed for each of the two communication lines whose ends are located in the specific section. A terrestrial / mobile communication system that allows stations to alternate at the same frequency . . Between the ground station and the mobile station on the mobile body via a leaky coaxial communication line stretched along the travel path of the mobile body and one end connected to the ground station and an antenna provided on the mobile body A communication system between a ground and a mobile body that communicates between each other, and covers one traveling route with a plurality of communication lines each having a ground station, and is identical from the ground station connected to each communication line. The signal for the mobile station of the mobile unit in the specific section including the ends of the two communication lines adjacent to each other is transmitted from the ground station with respect to the two communication lines. In a terrestrial / mobile communication system that alternately transmits at a frequency, the mobile station has means for specifying a mobile station located in the specific section, and the mobile station specification means is detected by a current position detection means provided in the mobile body. Current position value and previous By comparing with the set position value set corresponding to the specific section, it is determined whether or not the position is within the specific section on the mobile body side, and the determination result is transmitted to the ground station side to each ground station A terrestrial / mobile communication system that controls transmissions from Between the ground station and the mobile station on the mobile body via a leaky coaxial communication line stretched along the travel path of the mobile body and one end connected to the ground station and an antenna provided on the mobile body A communication system between a ground and a mobile body that communicates between each other, and covers one traveling route with a plurality of communication lines each having a ground station, and is identical from the ground station connected to each communication line. The signal for the mobile station of the mobile unit in the specific section including the ends of the two communication lines adjacent to each other is transmitted from the ground station with respect to the two communication lines. In a ground-mobile communication system that alternately transmits at a frequency, the mobile station is provided with means for specifying a mobile station located in the specific section, and the mobile station specifying means corresponds to the specific section on the travel route side of the mobile body. To be detected and A sensor provided on the moving body for detecting the detected portion, and by detecting the detected portion by the sensor, the moving body side determines whether the position is within the specific section, A terrestrial / mobile communication system that transmits the determination result to the ground station to control transmission from each ground station .