JP2018056623A - Communication system and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a time required for data transmission/reception between a controller and a plurality of traveling bodies and securely perform communication between both of them.SOLUTION: A communication system 100 comprises: a plurality of mobile bodies V that moves along a track T; and a controller 110 for performing communication with the mobile bodies V. The controller 110 includes: a request data transmission unit 113A that, through a feeder line (cable) F provided in a specific zone Z of the track T, performs broadcast transmission of request data to a mobile body V existing in the zone Z; and a response data reception unit 114A that, through a radio communication network, receives response data transmitted from the mobile body V. A mobile body V includes: a request data reception unit 121A for receiving request data; and a response data transmission unit 124A that, through the radio communication network, performs unicast transmission of response data in response to the request data to the controller 110.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a communication system and a communication method.

  In facilities such as factories and warehouses, a transport system that transports articles by a plurality of traveling bodies (transport vehicles) that travel along a track laid on the ground or near the ceiling is used. In such a transport system, a technique called feeder communication is used in which a feeder line is arranged along a track in a specific section of the track and communication between the feeder line and the traveling body is performed ( For example, see Patent Document 1). In Patent Document 1, a ground-side controller polls and transmits request data to a traveling body existing in a specific section via a feeder line. The transport vehicle that has received the request data returns response data to the controller via the feeder line. Thus, in feeder communication, bidirectional communication is possible and full-duplex communication is possible.

JP 2006-313463 A

  The above-described feeder communication is weak in radio field intensity compared to wireless communication such as a wireless LAN (Local Area Network) or Bluetooth (registered trademark), is susceptible to electromagnetic noise, and may cause a communication abnormality. There is a problem such as high. Therefore, in an environment where many devices are installed, such as a manufacturing factory, the influence of electromagnetic noise or the like becomes significant. Therefore, it is conceivable to use a wireless LAN instead of feeder communication. However, since communication by wireless LAN is half-duplex communication unlike feeder communication, the controller polls request data from a controller to a plurality of traveling bodies, and then the controller transmits response data transmitted from each traveling body. There is a problem that it takes time to receive.

  In addition, since wireless LANs are generally used for other purposes, there is a problem that the use of the wireless LAN for communication with a traveling body increases the load on the line, and there is also a security problem. ing. On the other hand, in feeder communication, when multicast transmission is performed from the controller, response data returned from a plurality of traveling bodies is transmitted through the feeder line, collision occurs, and the response data is damaged due to data collision. there is a possibility.

  In view of the above circumstances, the present invention reduces a time required for data transmission / reception in communication between a plurality of traveling bodies and a controller, and can reliably perform communication between the two. The purpose is to provide.

  The present invention is a communication system comprising a plurality of moving bodies that move along a track and a controller that communicates with the plurality of moving bodies, wherein the controller has a specific section in the communication area. A request data transmission unit that broadcasts request data to a mobile unit existing in the section via a cable provided along the track so that the response is transmitted from the mobile unit existing in the section A response data receiving unit that receives data via a wireless communication network including a relay device that performs access control, and the mobile unit receives the request data transmitted from the controller, and the request Response data transmission that unicasts response data corresponding to the request data received by the data receiver to the controller via the wireless communication network And, with a.

  In addition, the request data transmission unit of the controller sends the request data to the mobile unit that has not received the response data by the response data reception unit while the predetermined time has elapsed from the transmission of the request data via the wireless communication network. Unicast transmission may be performed. Further, the request data transmission unit of the controller broadcasts the request data to the mobile unit existing in the section via the cable, and unicasts the mobile unit via the wireless communication network. When the request data receiving unit receives both the request data broadcast-transmitted via the cable and the request data unicast-transmitted via the wireless communication network, the data transmitting unit converts the request data to one of the request data In response, the response data may be unicasted.

  Further, the present invention is a communication method for performing communication with a plurality of mobile bodies moving along a track, and is provided along the track so that a specific section of the track becomes a communication area. A relay device that broadcasts request data from a controller to a mobile unit existing in a section via a cable, and a mobile unit that receives the request data performs access control on response data corresponding to the request data And unicast transmission to the controller via a wireless communication network including, and the controller receiving response data unicast transmitted from the traveling body.

  Note that the summary of the invention described above does not enumerate all necessary features of the present invention. Also, a sub-combination of these feature groups can also be an invention.

  According to the communication system and the communication method of the present invention, the request data from the controller to the mobile body is broadcasted via the cable, and the response data from the mobile body to the controller is unicasted via the wireless communication network. Therefore, the time required for data transmission / reception can be shortened. In addition, since response data from the mobile unit to the controller is unicast transmitted via a wireless communication network including a relay device that performs access control, damage to the response data can be prevented even if a collision occurs. In addition, since request data from the controller to the moving body is broadcasted via a cable provided in a specific section, it is difficult to receive data away from this section, so security can be ensured.

  In addition, for a mobile unit that has not received the response data by the response data receiving unit within a predetermined time since the transmission of the request data, the request data transmitting unit of the controller unicasts the request data via the wireless communication network. In the transmission communication system, the request data can be reliably transmitted to the traveling body via the wireless communication network even when transmission via the cable is not available. Also, request data from the controller to the mobile unit is broadcasted via a cable and unicasted via a wireless communication network, and the mobile unit unicasts response data according to one of the request data. In a communication system for transmission, request data can be received from a plurality of routes, and response data can be reliably transmitted based on any one of the request data.

It is a figure which shows an example of the communication system which concerns on embodiment. It is a figure which shows an example of the functional block structure of a controller. It is a figure which shows an example of the functional block structure of the control apparatus of a moving body. It is a figure which shows an example of the operation | movement sequence regarding the communication method which concerns on embodiment. It is a figure which shows another example of the operation | movement sequence of a communication method. It is a figure which shows another example of the operation | movement sequence of a communication method.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are described below. However, this is not always essential for the solution of the invention. FIG. 1 shows an example of a communication system 100 according to the embodiment. The communication system 100 is a system for performing communication in a transport system that transports articles using a plurality of transport vehicles VA, VB, and VC (hereinafter sometimes collectively referred to as a transport vehicle V) that travel along the track T. is there. Here, the transport system includes, for example, a transport system in which a transport vehicle travels along a track T laid near the ceiling or on the floor surface. The transport vehicle V is an example of a moving body, and an article transfer device or the like may be mounted thereon.

  The track T is laid near the ceiling or on the floor. However, when the track T is laid near the ceiling, the track T may be installed in a state of being suspended from the ceiling by a hanging bracket or the like. The track T is divided into a plurality of sections ZA and sections ZB (hereinafter may be collectively referred to as sections Z) by a manufacturing process or the like. Each of the transport vehicles VA, VB, and VC includes control devices 120A, 120B, and 120C (hereinafter, may be collectively referred to as the control device 120) for controlling the operation. The control device 120 controls operations related to running and stopping of the transport vehicle V according to control data received from the controller 110 described later or autonomously. Further, the control device 120 transmits information obtained by monitoring the state of the transport vehicle V to the controller 110 described later.

  The transport vehicle V traveling along the track T is managed by the host controller 130. The host controller 130 manages information related to the position of the transport vehicle V such as in which section Z it exists for all transport vehicles V. The host controller 130 acquires these pieces of information based on information acquired from the control device 120 by the controller 110 described later. The transport vehicle V present in the section Z is controlled by the controller 110 provided corresponding to each section Z. The controller 110 is provided corresponding to the section Z, and the controllers 110A and 110B are provided corresponding to the sections ZA and ZB, respectively.

  The controller 110 manages information related to the state (or control) of the transport vehicle V present in the corresponding section Z. The controller 110 may acquire such information directly from the control device 120, or may use information acquired by the host controller 130. Further, the controllers 110A and 110B send request data such as inquiry data for inquiring the state of the transport vehicle V to the control device 120 of the transport vehicle V existing in the corresponding section Z and control data for controlling the transport vehicle V. Request data transmission units 113A and 113B for transmission, and response data reception units 114A and 114B for receiving response data transmitted from the control device 120 as data in response to the request data. The control device 120 (typically, the control device 120A) of the transport vehicle V includes a request data receiving unit 121A that receives request data transmitted from the controller 110A, and response data that transmits response data corresponding to the request data. And a transmission unit 124A.

  In the communication system 100, the controller 110 and the control device 120 perform such communication. In the following description, a communication path from the controller 110 to the controller 120 is referred to as “downlink”, and a communication path from the controller 120 to the controller 110 is referred to as “uplink”. In the downlink in the communication system 100, a feeder line (cable) F provided along the track T is used as a physical medium for transmitting signals. The feeder line F is provided corresponding to each section Z, and is provided along the trajectory T from the start point to the end point of the section Z, for example. Feeder lines FA and FB (hereinafter sometimes collectively referred to as feeder line F) are provided corresponding to sections ZA and ZB, respectively. Instead of the feeder line F, a coaxial cable or a feed line for supplying power to the transport vehicle V may be used.

  Feeder lines FA and FB are respectively connected to modulators MA and MB (hereinafter sometimes collectively referred to as modulator M). The modulator M is connected to the controller 110 by an RS-232C cable or the like. The modulator M modulates and amplifies the signal that is the request data transmitted from the controller 110 and transmits the modulated signal to the feeder line F. If the transport vehicle V exists in the section Z, the control device 120 of the transport vehicle V can receive a signal from the feeder line F via the first input / output unit 128A (see FIG. 3).

  As shown in FIG. 1, the control devices 120A, B, and C of the transport vehicles VA, VB, and VC existing in the section ZA can receive request data transmitted from the controller 110A and correspond to other sections ZB. The request data transmitted from the controller 110 </ b> B is not received or is difficult to receive because the signal from the feeder line F is weak. Similarly, in a communication device other than the transport vehicle V, a signal from the feeder line F arranged in the section cannot be received or is difficult to receive at a place away from the section Z (for example, the section ZB). That is, communication via the feeder line F is established only (substantially) only with the transport vehicle V traveling on the track T along the feeder line F (or provided with the feeder line F). Moreover, even when the frequency at which the digital signal is modulated is different between the modulators M provided in the adjacent sections Z so as not to interfere with the request data transmitted from the controller 110 corresponding to the adjacent section Z. Good. Further, the output of the modulator M may be adjusted so that the signal from the feeder line F can be received only in the section Z in which the feeder line F is provided.

  In the uplink in the communication system 100, communication is performed via a wireless communication network including a wireless LAN access point WAP. The wireless LAN access point WAP is a radio wave relay that connects terminals with a wireless LAN, and also has a function of connecting to a wired LAN. The wireless LAN access point WAP communicates with the control device 120 via a wireless LAN. The wireless LAN access point WAP communicates with the controller 110 and the host controller 130 via a wired LAN. The wireless LAN access point WAP is an example of a relay device in the present embodiment. In addition, the communicable distance between the wireless LAN access point WAP and the terminal is generally longer than at least the communicable distance between the feeder line F and the terminal.

  The wireless LAN access point WAP employs CSMA / CA (Carrier Sense Multiple Access with Collision Aviation) as a wireless LAN access control method. That is, since collision cannot be detected in the wireless LAN, each terminal transmits data after confirming that the communication path is continuously available for a certain time or more. The wireless LAN access point WAP also functions as a switching hub. That is, the wireless LAN access point WAP temporarily stores the received data in a memory or the like, and then analyzes the destination and transmits it only to necessary devices. In this embodiment, the wireless LAN access point WAP adopting CSMA / CA as a wireless LAN access control method or functioning as a switching hub is an example of “performing access control” in the present embodiment. In this embodiment, an example in which one wireless LAN access point WAP is used will be described. However, a plurality of wireless LAN access points may be provided.

  The wireless communication network is also used as a downlink in the communication system 100. That is, the control device 120 can transmit and receive data to and from the controller 110 and the host controller 130 via the wireless communication network.

  In the communication system 100, the controller 110 broadcasts request data for requesting the control devices 120 of the transport vehicles VA, VB, and VC existing in the corresponding section Z from the request data transmission unit 113A via the feeder line FA. Send. Here, broadcasting is transmitting data to an unspecified number of other parties. In the present embodiment, since request data is broadcasted via a feeder line F provided so that the section Z becomes a communication area, only the control device 120 of the transport vehicle V existing in the section Z receives the request data. Can be received.

  When the request data receiving unit 121A or the like receives the request data transmitted from the controller 110, the control device 120 of the transport vehicle V existing in the section Z receives response data corresponding to the request data from the response data transmitting unit 124A by wireless communication. Unicast transmission over the network. Here, unicast refers to transmitting data to a specific partner by designating a single address. In the present embodiment, the control device 120 transmits the response data by specifying the address of the controller 110 that is the transmission source of the request data. Thus, the controller 110 can grasp the state of the transport vehicle V and the control result by receiving the response data transmitted from the control device 120 by the response data receiving unit 114A.

  In the present embodiment, an example in which one feeder line F, one modulator M, and one controller 110 are provided corresponding to one section Z will be described. However, a plurality of feeder lines, a plurality of modulators, and a plurality of controllers may be provided in the section Z of the transport system. For example, a plurality of feeder lines F may be arranged in one section Z, or a plurality of sections Z may be managed by one controller 110. When a plurality of sections Z are managed by one controller 110, the controller 110 transmits request data with different transmission timings for different sections Z, and the control device 120 of the transport vehicle V receives the data at a predetermined timing. The requested data may be used.

  FIG. 2 shows an example of a functional block configuration of the controller 110A. The controller 110A includes an upper data receiving unit 111A, a request data generating unit 112A, a request data transmitting unit 113A, a response data receiving unit 114A, an upper data transmitting unit 115A, and an information storage unit 116A. In addition, the controller 110A includes a first input / output unit 118A and a second input / output unit 119A. Hereinafter, functions and operations of each component will be described. Note that the controllers 110B,... Other than the controller 110A have the same components as the components of the controller 110A.

  The upper data receiving unit 111A receives the data transmitted from the upper controller 130. For example, the data transmitted from the host controller 130 includes data indicating information related to the transport vehicle V existing in the section ZA, data for controlling the transport vehicle V existing in the section ZA, and the like. The request data generation unit 112A generates request data for the control devices 120A, 120B, and 120C of the transport vehicles VA, VB, and VC existing in the section ZA. The request data generation unit 112A generates, as request data, inquiry data for inquiring about the states of the transport vehicles VA, VB, and VC, or control data for controlling the transport vehicles VA, VB, and VC.

  The request data transmission unit 113A transmits request data for making a request to the control devices 120A, 120B, and 120C of the transport vehicles VA, VB, and VC existing in the section ZA. The request data transmitted from the request data transmitting unit 113A is broadcasted from the feeder line F via the first input / output unit 118A. For example, the first input / output unit 118A converts the data sent as a digital signal from the request data transmission unit 113A into an analog signal and supplies it to the feeder line F.

  Further, the request data transmission unit 113A can transmit the request data via the wireless communication network to the transport vehicle V for which the response data reception unit 114A has not received the response data. Further, the request data transmitting unit 113A can broadcast the request data via the feeder line F and can also transmit the unicast via the wireless communication network.

  The response data receiving unit 114A sends response data unicast from the control devices 120A, 120B, and 120C of the transport vehicles VA, VB, and VC existing in the section ZA from the second input / output unit 119A via the wireless communication network. Receive. For example, the second input / output unit 119A converts the response data received as an analog signal into a digital signal and supplies the converted response data to the response data reception unit 114A.

  The upper data transmission unit 115 transmits data to the upper controller 130. For example, the data transmitted to the host controller 130 includes information about the transport vehicle V existing in the section Z. The information storage unit 116 stores, for example, information related to the transport vehicle V present in the section Z, information for controlling the transport vehicle V present in the section Z, and the like. Information regarding the transport vehicle V existing in the section Z may be updated with information indicated by data received by the response data receiving unit 114A of each controller 110A.

  The host controller 130 grasps in which section Z which transport vehicle V exists, and when the transport vehicle V enters a new section Z, the controller 110 manages the section Z. Then, data including information on the newly entering transport vehicle V is transmitted. The data to be transmitted may include, for example, information indicating the IP address of the control device 120 of the transport vehicle V in the wireless communication network. Information for controlling each transport vehicle V may be stored in advance in the host controller 130 or updated from various terminals.

  FIG. 3 is a diagram illustrating an example of a functional block configuration of the control device 120A in the transport vehicle VA. The control device 120A includes a request data reception unit 121A, a conveyance control unit 122A, a conveyance monitoring unit 123A, a response data transmission unit 124A, and an upper data transmission unit 125A. In addition, the transport vehicle VA includes a first input / output unit 128A and a second input / output unit 129A. Hereinafter, functions and operations of each component will be described.

  Note that the control device 120B, the control device 120C, and so on other than the control device 120A also have the same components as the components of the control device 120A. The request data receiving unit 121A receives the request data transmitted from the controller 110A via the first input / output unit 128A. For example, the first input / output unit 128A converts the request data received as an analog signal into a digital signal and supplies the digital data to the request data reception unit 121A.

  The conveyance control unit 122A controls the conveyance vehicle VA provided with the control device 120A. The conveyance control unit 122A controls, for example, the speed of the conveyance vehicle VA or the operation of the transfer device that transfers articles according to the control data. The conveyance monitoring unit 123A monitors the state of the conveyance vehicle VA. The conveyance monitoring unit 123 acquires, for example, the position of the conveyance vehicle VA using various sensors included in the conveyance vehicle V.

  The response data transmitting unit 124 unicasts response data corresponding to the request data receiving unit 121 receiving the request data from the second input / output unit 129A to the controller 110 via the wireless communication network. For example, the second input / output unit 129A converts the digital signal transmitted from the response data transmission unit 124A into an analog signal and transmits the analog signal. Further, when the request data receiving unit 121 receives both the request data broadcast-transmitted via the feeder line F and the request data unicast-transmitted via the wireless communication network, the response data transmitting unit 124A receives The response data can be unicasted according to either one of the request data.

  4 to 6 show a communication method according to the embodiment, and show an example of an operation sequence related to communication between the controller 110A and the transport vehicles VA, VB, and VC. In these operation sequences, an example will be described in which the controller 110A communicates with the transport vehicles VA, VB, and VC existing in the section ZA, assuming that the transport vehicle V exists at the position shown in FIG. In the description of these operation sequences, FIGS. 1 to 3 are referred to as appropriate.

  A communication method between the controller 110 and the control device 120 will be described with reference to the operation sequence shown in FIG. First, the request data generation unit 112A of the controller 110A generates request data R1 for the transport vehicles VA, VB, and VC existing in the section ZA. When the request data generation unit 112A generates the inquiry data for inquiring the state of the transport vehicle V as the request data R1, the information related to the transport vehicle V existing in the section ZA among the information stored in the information storage unit 116A. Referring to FIG. 4, the transport vehicle V existing in the section ZA is specified. In this example, the request data generation unit 112A specifies that the transport vehicles VA, VB, and VC exist in the section ZA. Subsequently, the request data generation unit 112A generates inquiry data for inquiring the state of each transport vehicle V to the transport vehicles VA, VB, and VC existing in the section ZA. Further, the request data generation unit 112A may generate control data for controlling each transport vehicle V as the request data R1.

  The request data generation unit 112A may generate the same request data R1 for the transport vehicles VA, VB, and VC existing in the section ZA when generating the request data R1 such as inquiry data and control data. Different request data may be generated. In addition, when transmitting different request data for every conveyance vehicle V, you may include the information which identifies the conveyance vehicle V in request data. The transport vehicles VA, VB, and VC may identify whether or not the data is addressed to the own vehicle from the received request data. The request data generation unit 112A sends the generated request data R1 to the request data transmission unit 113A. Further, when the request data generation unit 112A generates the request data R1, the request data generation unit 112A sends a list of IP addresses of the transport vehicles VA, VB, and VC existing in the section ZA to the response data reception unit 114A.

  Upon receiving the request data R1 sent from the request data generation unit 112A, the request data transmission unit 113A broadcasts the request data R1 via the first input / output unit 118A (step S101). At this time, the request data transmitting unit 113A sends notification data notifying that the request data R1 has been transmitted to the response data receiving unit 114A. The request data R1 is modulated and amplified by the modulator MA and transmitted to the feeder line FA. When the first input / output unit 128A included in each of the transport vehicle VA, the transport vehicle VB, and the transport vehicle VC receives a signal from the feeder line FA, the first input / output unit 128A outputs request data obtained by demodulating the signal to the control device 120A. To do.

  The request data receiving unit 121A of the control device 120A of the transport vehicle VA receives the input of the request data R1 output from the first input / output unit 128A, and performs processing according to the content of the request data R1. For example, when the request data receiving unit 121A receives, as the request data R1, inquiry data for inquiring the state of the transport vehicle VA, the request data receiving unit 121A sends the inquiry data to the transfer monitoring unit 123A. On the other hand, when the request data receiving unit 121A receives the control data for controlling the transport vehicle VA as the request data R1, the request data receiving unit 121A sends the control data to the transport control unit 122A.

  When the conveyance monitoring unit 123A of the control device 120A receives the inquiry data transmitted from the request data receiving unit 121A, the conveyance monitoring unit 123A transmits response data AA1 indicating the state of the conveyance vehicle VA to the response data transmission unit 124A. For example, if the content of the inquiry based on the inquiry data is an inquiry about the current position, the conveyance monitoring unit 123A sends response data AA1 indicating the latest position acquired from the position sensor to the response data transmission unit 124A.

  In addition, when the transfer control unit 122A of the control device 120A receives the control data sent from the request data receiving unit 121A, the transfer control unit 122A controls the transfer vehicle VA according to the control data and notifies that the control data has been received. The data AA1 is sent to the response data transmission unit 124A. For example, when the control data indicates the control content of the transport vehicle VA and the timing for performing the control, the transport control unit 122A controls the transport vehicle VA according to the timing specified by the control data.

  When the response data transmission unit 124A of the control device 120A receives the response data AA1 sent from the conveyance monitoring unit 123A or the conveyance control unit 122A, the response data AA1 is received from the second input / output unit 129A via the wireless communication network. Unicast transmission is performed to the controller 110 (step S102). Note that the control device 120A, the control device 120B, and the control device 120C, after transmitting the response data AA1, AB1, and AC1, respectively, confirm that the wireless LAN communication path is continuously available for a predetermined time or more before responding. Data may be sent. Further, since the wireless LAN access point WAP functions as a switching hub, the response data AA1, AB1, AC1 respectively received from the control devices 120A, 120B, 120C are sequentially transmitted to the controller 110A. In the example shown in FIG. 4, the response data AB1, AC1, and AA1 are transmitted in unicast order.

  When the response data receiving unit 114A of the controller 110A sequentially receives response data AA1, AB1, and AC1 unicast transmitted from the control devices 120A, 120B, and 120C from the second input / output unit 119A via the wireless communication network, a predetermined data is received. Execute the process. When the response data receiving unit 114A receives response data AA1, AB1, and AC1 indicating the states of the transport vehicles VA, VB, and VC, the information storage unit 116A stores information on the states of the transport vehicles VA, VB, and VC in the information storage unit 116A. .

  After receiving the response data AA1, AB1, and AC1, the controller 110A broadcasts new request data R2 to the transport vehicles VA, VB, and VC in the same manner as described above (step S101), and the transport vehicles VA, VB, and VC are The response data AA2, AB2, AC2 corresponding to the request data R2 is transmitted to the controller 110A. By repeating such an operation, communication between the controller 110A and the transport vehicles VA, VB, and VC is performed.

  In this way, in the communication system 100, the request data R1 from the controller 110A to the control device 120A and the like is broadcasted via the feeder line FA in the section ZA, so that the transport vehicle V that does not exist in the section ZA sends the request data R1. Cannot receive, can solve the security problem by broadcasting. Further, in the communication system 100, the response data AA1 and the like from the control device 120A and the like to the controller 110 are unicast transmitted via the wireless communication network including the wireless LAN access point WAP. Therefore, even if a collision occurs, the response data AA1 Etc. can be prevented.

  Further, in the communication system 100, the request data R1 from the controller 110A is broadcasted via the feeder line F in the section ZA, and the wireless LAN access point WAP is transmitted to the plurality of response data AA1 from the control device 120A. Since the unicast transmission is performed via the wireless communication network including the time, the time required for data transmission / reception can be reduced.

  When the response data receiving unit 114A receives the notification data transmitted from the request data transmitting unit 113A, the response data from the transport vehicle V corresponding to the list of IP addresses indicated by the data received from the request data generating unit 112A. You may monitor whether AA1 etc. were received normally. For example, every time response data is received, the response data receiving unit 114 specifies an IP address of a transmission source such as the response data AA1 and collates it with a list of IP addresses. Subsequently, the response data receiving unit 114 receives the response data from the IP addresses in the list based on the condition that a predetermined time has elapsed after receiving the notification data (after the request data R1 and the like are broadcasted). It may be determined that the response data could not be normally received with respect to those in which the IP address that is the transmission source such as AA1 could not be specified.

  In the communication system 100 described above, it is conceivable that the controller 110 that broadcasts the request data R1 or the like cannot receive the response data AA1 or the like from the transport vehicle V that exists in the corresponding section Z. As a cause of such a problem, since the feeder line F is used for broadcast transmission of the request data R1 and the like, it cannot be normally received on the transport vehicle V side due to the influence of electromagnetic noise, for example. Conceivable.

  The communication system 100 according to the present embodiment includes a configuration for recovering the transport vehicle V that cannot receive the request data R1. With reference to the operation sequence shown in FIG. 5, a recovery method for the target transport vehicle V for which the controller 110A could not receive the response data will be described. In this example, it is assumed that the control device 120C cannot receive the request data R1 from the feeder line FA, and as a result, the controller 110A cannot receive the response data AC1 from the transport vehicle VC.

  Similar to the operation sequence shown in FIG. 4, when the request data R1 is broadcast from the controller 110A (step S101), the transport vehicles VA and VB receive the request data R1 from the feeder line FA, and the control devices 120A and 120B. Transmits unicast response data AA1 and AB1 respectively corresponding to the request data R1 to the controller 110A via the wireless communication network (step S102). However, the control device 120C of the transport vehicle VC does not transmit the response data AC1 because the request data receiving unit 121C has not received the request data R1.

  The response data receiving unit 114A of the controller 110A cannot normally receive the response data AC1 from the control device 120C based on the fact that a predetermined condition such as a predetermined time has elapsed since the request data R1 was broadcasted. It is determined that Subsequently, the response data receiving unit 114A sends data specifying the transport vehicle VC that has not been able to normally receive the response data AC1 to the request data generating unit 112A. When the request data generation unit 112A of the controller 110A receives the data transmitted from the response data reception unit 114A, the request data generation unit 112A generates request data R1S for unicast transmission to the transport vehicle VC specified by the data.

  The request data generation unit 112A, for example, as the request data R1S, for example, an IP header portion in which the IP address of the transport vehicle VC for which the response data could not be normally received is designated, and data having the same contents as the request data R1 transmitted by broadcast An IP packet including the portion is generated. The request data generation unit 112A sends the generated request data R1S to the request data transmission unit 113A. Upon receiving the request data R1S sent from the request data generation unit 112A, the request data transmission unit 113A unicasts the request data R1S from the second input / output unit 119A via the wireless communication network (step S103). .

  The control device 120C of the transport vehicle VC receives the request data R1S transmitted from the controller 110A via the second input / output unit 129C (corresponding to the code 129A in FIG. 3), and the request data receiving unit 121C (the code in FIG. 3). Is equivalent to 121A), the processing corresponding to the request data R1S is executed in the same manner as the operation sequence shown in FIG. Subsequently, the response data transmission unit 124C (see reference numeral 124A in FIG. 3) of the control device 120C transmits the response data AC1 corresponding to the request data R1S from the second input / output unit 129C to the controller 110A via the wireless communication network. Cast transmission is performed (step S104).

  Thus, in the communication system 100, since the request data is unicasted again via the wireless communication network to the transport vehicle V that has not received the response data, it can be reliably recovered. The same applies to the case where the controller 110A does not receive the response data AA1, AB1 from the transport vehicles VA, VB existing in the section ZA.

  In the communication system 100, the request data R1 can be transmitted using a redundant downlink. With reference to the operation sequence shown in FIG. 6, a description will be given of a method in which the controller 110 transmits the request data R1 using a redundant downlink. The request data generation unit 112A of the controller 110A transmits request data R1 for broadcast transmission to the transport vehicles VA, VB, and VC existing in the section ZA through the feeder line FA in the same manner as the operation sequence shown in FIG. Is generated.

  Further, the request data generation unit 112A generates request data R1S for unicast transmission via the wireless communication network to the transport vehicles VA, VB, and VC existing in the section ZA. The request data generation unit 112A generates an IP packet including an IP header portion in which the IP addresses of the transport vehicles VA, VB, and VC existing in the section ZA are specified, and a data portion having the same content as the request data R1. In this example, the request data generation unit 112A generates, as request data R1S, an IP packet in which the IP addresses of the control devices 120A, 120B, and 120C are specified in the IP header portion.

  Subsequently, the request data generation unit 112A sends the request data R1 and the request data R1S to the request data transmission unit 113A. Upon receiving the request data R1 and the request data R1S, the request data transmission unit 113A broadcasts the request data R1 via the feeder line F (step S101A), and the request data R1S is unicast via the wireless communication network. Transmit (step S101B). Subsequently, the request data transmission unit 113A transmits notification data notifying that the request data R1 and R1S have been transmitted to the response data reception unit 114A.

  The request data receivers 121A, 121B, and 121C of the control devices 120A, 120B, and 120C receive the request data R1 that is broadcasted via the feeder line FA and the request data R1S that is unicasted via the wireless communication network. Each of them will be received, but processing corresponding to the contents of either one of the request data is performed.

  The request data R1 and the request data R1S may include identification information for identifying the contents. The request data receiving unit 121A and the like determine whether or not the contents of the request data received in the past are the same by referring to the identification information included in the received request data R1 and R1S. For example, the process according to the content of the request data is performed, and if it is the same, the request data received later may be discarded. That is, the request data receiving unit 121 may perform processing according to the content of the request data received first out of the request data R1 and the request data R1S.

  Further, since communication using the feeder line F is more desirable from the viewpoint of security than communication using the wireless communication network, information not included in the request data R1S may be included in the request data R1. In this case, when the request data receiving unit 121 receives the request data R1 first, the request data receiving unit 121 performs processing according to the request data R1, and discards the request data R1S received later. In addition, when the request data receiving unit 121 receives the request data R1S first, if it can receive the request data R1 having the same content before the predetermined waiting time elapses, the request data receiving unit 121 performs processing according to the request data R1 first. The received request data R1S may be discarded.

  After the processing according to whether the request data R1 and R1S is inquiry data or control data is executed, the response data transmission unit 124A of the control device 120C receives the response data AA1 and the response data AA1 according to the request data R1 and R1S. AB1 and AC1 are unicast transmitted to the controller 110A via the wireless communication network (step S102).

  Thus, in the communication system 100, the request data R1 is broadcasted via the feeder line F, and the request data R1S is unicasted via the wireless communication network. Accordingly, the controller 110A receives the response data AA1 or the like corresponding to any one of the request data regardless of the presence or absence of the response data AA1 or the like, so that the communication with the transport vehicle V is reliably performed in a short time. be able to.

  The upper data receiving unit 111, the request data generating unit 112, the request data transmitting unit 113, the response data receiving unit 114, the upper data transmitting unit 115, and the information storage unit 116 of the controller 110 described above are read by the computer being read by the computer. It may be realized as a specific means in which software and hardware resources cooperate. Similarly, the request data reception unit 121, the conveyance control unit 122, the conveyance monitoring unit 123, the response data transmission unit 124, and the higher-level data transmission unit 125 in the control device 120 of the conveyance vehicle V are read by the computer. It may be realized as a specific means in which software and hardware resources cooperate.

  As mentioned above, although embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in above-described embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above-described embodiments. Embodiments to which such changes or improvements are added are also included in the technical scope of the present invention. In addition, the execution order of each process such as operation, step, etc. in the system, method, apparatus, program, and recording medium shown in the claims, specification, and drawings uses the output of the previous process in the subsequent process. As long as it is not, it is realizable in arbitrary orders. Further, even though the operations in the above-described embodiments are described using “first”, “next”, “follow”, and the like for convenience, it does not mean that the operations are essential in this order.

  In the above-described embodiment, a wireless communication network including the wireless LAN access point WAP is used. However, the present invention is not limited to this. For example, a wireless communication network including a Bluetooth (registered trademark) access point may be used as a wireless communication network including a relay device that performs access control. In that case, the Bluetooth (registered trademark) access point may be a stationary type connected to a wired LAN such as a wireless LAN access point, or any one of the transport vehicles V may be connected to the Bluetooth (registered trademark). ) It may function as an access point. Thereby, power consumption can be suppressed as compared with a wireless communication network including the wireless LAN access point WAP.

DESCRIPTION OF SYMBOLS 100 ... Communication system 110A, 110B ... Controller 113A, 113B ... Request data transmission part 114A, 114B ... Response data reception part 120A, 12B, 120C ... Control apparatus 121A ... Request data reception Unit 124A ... Response data transmission unit 130 ... Host controller FA, FB ... Feeder wire (cable)
T: Tracks VA, VB, VC ... Conveyor vehicle (moving body)
WAP ... Wireless LAN access point (relay device)
Z ... Section

Claims (4)

A communication system comprising a plurality of moving bodies that move along a track and a controller that communicates with the plurality of moving bodies,
The controller is
A request data transmission unit that broadcasts request data to the mobile body existing in the section via a cable provided along the path so that a specific section of the track becomes a communication area. When,
A response data receiving unit that receives response data transmitted from a mobile unit existing in the section via a wireless communication network including a relay device that performs access control, and
The moving body is
A request data receiving unit for receiving request data transmitted from the controller;
A response data transmitting unit that unicasts response data corresponding to the request data received by the request data receiving unit to the controller via the wireless communication network.   The request data transmission unit of the controller transmits the request data to the mobile unit that has not received response data by the response data reception unit while a predetermined time has elapsed since the transmission of the request data. The communication system according to claim 1, wherein unicast transmission is performed via a communication network. The request data transmission unit of the controller broadcasts the request data to the mobile unit existing in the section via the cable, and unicasts the transmission via the wireless communication network.
The response data transmission unit of the mobile body has received both the request data broadcast-transmitted via the cable and the request data unicast-transmitted via the wireless communication network. 2. The communication system according to claim 1, wherein the response data is unicast transmitted according to any one of the request data. A communication method for communicating with a plurality of mobile objects moving along a track,
Broadcast request data from the controller to the mobile unit existing in the section via a cable provided along the path so that a specific section of the track becomes a communication area; ,
The mobile that has received the request data transmits unicast response data corresponding to the request data to the controller via a wireless communication network including a relay device that performs access control;
A controller receiving the response data unicast transmitted from the traveling body.

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