TW202237513A - Wireless communication system and control method for wireless communication system - Google Patents

Abstract

In the present invention, a first communication device (10b) comprises a communication unit (52) that: triggered by reception of a pairing signal from a first transport truck (4), receives a command signal from the first transport truck (4); sends a response signal to the first transport truck (4) each time the command signal is received, thereby establishing interlocked communication with the first transport truck (4); and, while interlocked communication with the first transport truck (4) remains established, avoids establishing interlocked communication with a second transport truck (6). If a communication unit (46) of the second transport truck (6) is not able to receive the response signal even after a prescribed time has elapsed since a command signal was sent to the first communication device (10b), the communication unit changes the timing at which to send a command signal that is to be sent next after said command signal from the timing based on a prescribed cycle.

Description

Wireless communication system and control method of wireless communication system

The invention relates to a wireless communication system and a control method of the wireless communication system.

There is known a semiconductor manufacturing system, which is equipped with an overhead traveling transfer trolley for transporting a front opening wafer box (FOUP, Front Opening Unified Pod) storing semiconductor wafers, and a semiconductor manufacturing device for processing semiconductor wafers .

In this semiconductor manufacturing system, the communication system between the transfer trolley and the communication device connected to the port of the semiconductor manufacturing device is used to implement the E84 chain sequence of the International Semiconductor Equipment and Materials Industry Association (SEMI, Semiconductor Equipment and Materials International) ( Interlock communication of interlock sequence). When the FOUP is transferred between the transport cart and the port, communication data is exchanged between the transport cart and the communication device through the chain communication described above.

However, Patent Document 1 discloses a technique in which, when a mobile station cannot receive a call setup acceptance from a base station, it reads an upper channel registered as a peripheral area, and sends a call request to the target base station. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-374550

(Problem to be solved by the invention)

When the technique disclosed in Patent Document 1 is applied to the above-mentioned semiconductor manufacturing system, the following problems arise. For example, when the chain communication between the two transport vehicles and one communication device is started approximately simultaneously, the two communication data transmitted from the two transport vehicles may collide and a communication error may occur. As a result, there is a possibility that the interlocking communication of the two conveyance vehicles will fail.

The present invention was made in view of such a problem, and an object of the present invention is to provide a wireless communication system and a control method of the wireless communication system that can stably perform chain communication between a transport vehicle and a communication device. (technical means to solve the problem)

In order to achieve the above object, a wireless communication system according to an aspect of the present invention includes: a plurality of conveyance carts, which convey objects to be conveyed by moving along rails; The port where the object to be conveyed is transferred to, and wirelessly communicates with each of the plurality of conveying carts; wherein, each of the plurality of conveying carts has a first communication part; the first communication part is, (i) Send a pairing signal to the above-mentioned communication device, (ii) When the above-mentioned communication device receives the above-mentioned pairing signal as a trigger (frigger), the above-mentioned port will be used for the chain communication of transferring the above-mentioned conveyed object in a predetermined period The first communication data is sent to the communication device, and the second communication data of the chain communication is received from the communication device as a response to the first communication data, thereby establishing the chain communication with the communication device; The communication device has a second communication unit; the second communication unit (iii) receives the above-mentioned pairing signal from a specific transport trolley among the above-mentioned plurality of transport trolleys, (iv) when receiving the above-mentioned pairing signal as a trigger, receives the signal from the above-mentioned The above-mentioned first communication data of a specific transport trolley, and whenever the above-mentioned first communication data is received, the above-mentioned second communication data is sent to the above-mentioned specific transport trolley, thereby establishing the above-mentioned Chain communication, (v) During the period of establishing the above-mentioned chain communication with the above-mentioned specific transport trolley, avoid establishing the above-mentioned chain communication with other transport vehicles other than the above-mentioned specific transport trolley; the above-mentioned first communication department shall If the above-mentioned first communication data is sent to the above-mentioned communication device and the above-mentioned second communication data cannot be received after a predetermined time has elapsed, the time point at which the first communication data should be sent after the first communication data shall be sent from the time point based on the above-mentioned established The time point of the cycle is changed.

According to this aspect, when the first communication unit of the other transport vehicle cannot receive the second communication data after a predetermined time elapses after sending the first communication data to the communication device, it will send the first communication data after the first communication data. The time point of the first communication data is changed from the time point according to the predetermined cycle. In this way, even when the predetermined cycle of sending the first communication data from a specific transport trolley coincides with the predetermined cycle of sending the first communication data from other transport trolleys, it is still possible to avoid the first communication data from the specific transport trolley being different from those from other transport carts. The first communication data of the trolley conflicts. As a result, the communication device can receive the first communication data, so that the chain communication between the specific transport vehicle and the communication device can be performed stably without causing a communication error.

It can also be configured such that, for example, the above-mentioned first communication unit of the above-mentioned other transport trolley, when receiving the above-mentioned second communication data of the chain communication established between the above-mentioned specific transport trolley and the above-mentioned communication device, will not The first communication data is sent to the communication device.

According to this aspect, when chain communication is established between a specific transport vehicle and the communication device, it is possible to avoid unnecessary transmission of first communication data to the communication device by the first communication units of other transport vehicles.

It can also be configured such that, for example, the above-mentioned first communication unit of the above-mentioned other transport trolley, when receiving the above-mentioned second communication data of the above-mentioned chain communication established between the above-mentioned specific transport trolley and the above-mentioned communication device, according to the second The identification information of the above-mentioned communication device and the identification information of the above-mentioned specific transport trolley included in the communication data, and it is determined that the above-mentioned chain communication is established between the above-mentioned communication device and the above-mentioned specific transport trolley.

According to this aspect, the above-mentioned first communication unit of another transport vehicle can easily determine the communication device and the specific transport vehicle by using the identification information of the communication device included in the received second communication data and the identification information of the specific transport vehicle. A chain of communication is established between them.

It may also be configured such that, for example, the second communication unit of the communication device receives the first communication data from the other transport vehicles while the chain communication is established with the specific transport vehicle. , the first communication data is not output to the port.

According to this aspect, it is possible to avoid simultaneous chain communication between each of a plurality of transport vehicles and one port.

It may also be configured such that, for example, each of the above-mentioned plurality of conveyance carts further has a control unit, and the above-mentioned control unit of the above-mentioned other conveyance cart is, when the above-mentioned chain communication is established between the above-mentioned communication device and the above-mentioned specific conveyance cart, then execute Either one of the first control and the second control; the first control system moves the other transport vehicles to leave the port; the second control system controls the first communication unit so that the chain communication ends The other transport vehicles are kept on standby until the above-mentioned chain communication is completed, and the above-mentioned pairing signal is transmitted to the above-mentioned communication device.

According to this aspect, when chain communication is established between the communication device and a specific transport vehicle, it is possible to appropriately control the operation of other transport vehicles.

It may also be configured such that, for example, the control unit of the other transport vehicle executes any one of the first control and the second control based on the progress of the chain communication between the communication device and the specific transport vehicle. By.

According to this aspect, according to the progress status of the chain communication between the communication device and a specific transport vehicle, the operation of other transport vehicles can be appropriately changed, thereby suppressing unnecessary operations of other transport vehicles.

It can also be configured such that, for example, the track includes a first track and a second track arranged at different positions in the vertical direction, and the specific transport trolley and the other transport trolleys can be placed on the first track and the second track respectively, The above-mentioned conveyed object is transferred between the above-mentioned ports.

According to this aspect, each conveyance efficiency of a plurality of conveyance carts can be improved.

For example, it may also be configured that the track includes a first track and a second track arranged at different positions in a horizontal direction perpendicular to the extending direction of the track, and the specific transport trolley and the other transport trolleys mentioned above can be placed on the above-mentioned rails respectively. On the first rail and the second rail, the object to be conveyed is transferred between the port and the port.

According to this aspect, it is possible to improve the respective conveying efficiencies of a plurality of conveying carts.

It can also be configured such that, for example, the above-mentioned rails include a plurality of rails arranged in a grid in a horizontal plane, and the above-mentioned specific transfer trolley and the above-mentioned other transfer trolleys can be located at different first positions and second positions on the plurality of rails, respectively. position to transfer the object to be transported between the port and the port.

According to this aspect, it is possible to improve the respective conveying efficiency of a plurality of conveying carts.

A method for controlling a wireless communication system according to an aspect of the present invention, wherein the wireless communication system includes: a plurality of transport carts that transport objects by moving along rails; and a communication device connected to the The port where each of the above-mentioned plurality of transport trolleys is transferred to the above-mentioned conveyed object performs wireless communication with each of the above-mentioned plurality of transport trolleys; the control method of the wireless communication system includes the following steps: (a) the above-mentioned plurality of The step of sending a pairing signal to the above-mentioned communication device by a specific transport trolley among the transport trolleys; (b) the step of receiving the above-mentioned pairing signal from the above-mentioned specific transport trolley by the above-mentioned communication device; (c) receiving the above-mentioned pairing signal by the above-mentioned communication device As a trigger, the above-mentioned specific transport trolley sends the first communication data of chain communication to the above-mentioned port to the above-mentioned communication device at a predetermined period, and the above-mentioned communication device receives the above-mentioned first communication data every time , the second communication data of the above-mentioned chain communication is sent to the above-mentioned specific transport trolley as a response to the above-mentioned first communication data, thereby establishing the above-mentioned chain communication between the above-mentioned specific transport trolley and the above-mentioned communication device ; (d) When the above-mentioned specific transport trolley fails to receive the above-mentioned second communication data after a predetermined period of time after sending the above-mentioned first communication data to the above-mentioned communication device, it will send the first communication data that should be sent after the first communication data. The step of changing the time point of the communication data from the time point according to the above-mentioned predetermined period; and (e) during the establishment of the above-mentioned chain communication between the above-mentioned communication device and the above-mentioned specific transport trolley, avoiding contact with other parties other than the above-mentioned specific transport trolley Steps for establishing the above-mentioned chain communication between other transport vehicles.

According to this aspect, when other transport vehicles cannot receive the second communication data after a predetermined time elapses after sending the first communication data to the communication device, the time point at which the first communication data should be sent after the first communication data is sent Change from a point in time based on a predetermined cycle. In this way, even when the predetermined cycle of sending the first communication data from a specific transport trolley coincides with the predetermined cycle of sending the first communication data from other transport carts, it is still possible to prevent the first communication data from the specific transport trolley from colliding with those from other transport carts. A conflict occurred in the first communication data. As a result, the communication device can receive the first communication data, so that the chain communication between the specific transport vehicle and the communication device can be stably performed without causing a communication error.

Furthermore, the present invention can be realized not only by a device, but also by a method that uses the processing means constituting the device as steps, or by a program that enables a computer to execute these steps, or by a computer-readable program that records the program. It is realized by taking a recording medium such as a CD-ROM (Compact Disc-Read Only Memory), or by using information, data or signals representing the program. Moreover, such programs, information, data and signals may also be distributed via communication networks such as the Internet. (compared to the effect of previous technology)

According to the wireless communication system or the like according to one aspect of the present invention, it is possible to stably perform chain communication between the transport vehicle and the communication device.

Embodiments of the present invention will be described in detail below using the drawings. In addition, the embodiment described below is an example showing generality or concreteness. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, steps, and sequence of steps shown in the following embodiments are examples, and are not intended to limit the gist of the present invention. In addition, among the constituent requirements in the following embodiments, the constituent requirements not described in the independent claims are described as arbitrary constituent requirements.

(implementation form) [1. Outline of communication system] First, an outline of a radio communication system 2 according to the embodiment will be described with reference to FIGS. 1 to 3 . FIG. 1 is a diagram showing an outline of a radio communication system 2 according to an embodiment. FIG. 2 is a diagram showing an example of E84 chain sequence when FOUP 14 is loaded. FIG. 3 is a diagram showing an example of E84 chain sequence when FOUP 14 is unloaded.

As shown in FIG. 1 , the wireless communication system 2 is, for example, a system built in a semiconductor manufacturing factory. In a semiconductor manufacturing factory, a plurality of semiconductor manufacturing devices 8 are installed. The wireless communication system 2 includes a first transport vehicle 4 , a second transport vehicle 6 , a first communication device 10 , and a second communication device 12 .

In addition, in a semiconductor manufacturing factory, a plurality of (for example, several hundred) transfer carts are actually arranged, but for convenience of description, only the first transfer cart 4 and the second transfer cart 6 are shown in FIG. 1 . Also, in a semiconductor manufacturing factory, a plurality of (for example, several thousand) semiconductor manufacturing devices are actually installed, but for convenience of description, only one semiconductor manufacturing device 8 is shown in FIG. 1 .

The first transport trolley 4 is an overhead transport trolley for transporting the FOUP 14 (an example of the object to be transported) storing semiconductor wafers, and is a so-called overhead hoist transfer vehicle (OHT, Overhead Hoist Transfer). The first transport cart 4 travels unmanned along the first rail 16 provided on the ceiling wall side of the semiconductor manufacturing factory.

In the inside of the first transport cart 4, a gripper 18 for gripping the FOUP 14 is mounted. The gripper 18 can be raised and lowered relative to the first transport cart 4 . For example, when the FOUP 14 is transferred between the first transport cart 4 and the first port 26 (described below) of the semiconductor manufacturing apparatus 8, the first transport cart 4 is stopped at a position directly above the first port 26, and the The holding part 18 descends from the first transfer trolley 4 to the vicinity of the first port 26. In addition, when the transfer of the FOUP 14 is completed, the gripper 18 is lifted from the vicinity of the first port 26 to the first transfer cart 4 and stored inside the first transfer cart 4 .

The second transfer cart 6 is, like the first transfer cart 4 , an overhead traveling transfer cart for transferring the FOUP 14 storing semiconductor wafers. The second transport trolley 6 travels unmanned along the second rail 20 provided on the ceiling wall side of the semiconductor manufacturing factory. The first rail 16 and the second rail 20 are arranged at different positions in the vertical direction directly above the first port 26 of the semiconductor manufacturing device 8 . In the example shown in FIG. 1 , the second rail 20 is arranged on the upper side (directly above) the first rail 16 . In addition, only one of the first rail 16 and the second rail 20 may be arranged directly above the first port 26 of the semiconductor manufacturing device 8 instead of this arrangement. Moreover, the gripping part 21 for gripping the FOUP 14 is mounted in the inside of the 2nd conveyance cart 6 similarly to the 1st conveyance cart 4. As shown in FIG. The grasping unit 21 can be raised and lowered relative to the second transport cart 6 .

The semiconductor manufacturing device 8 is a device for processing or temporarily placing semiconductor wafers stored in the FOUP 14 , and is installed below the first track 16 and the second track 20 . The semiconductor manufacturing device 8 has: a first loading and unloading port 22 and a second loading and unloading port 24 for loading and unloading semiconductor wafers stored in the FOUP 14 into and out of the semiconductor manufacturing device 8; It is arranged near the first import/export port 22 ; and the second port 28 is arranged near the second import/export port 24 .

The first port 26 is a loading port for loading the FOUP 14 . The FOUP 14 is delivered between the first port 26 and the gripping portion 18 of the first transport cart 4 (or the gripping portion 21 of the second transport cart 6). Then, the semiconductor wafer stored in the FOUP 14 is transferred to and from the semiconductor manufacturing apparatus 8 through the first loading and unloading port 22 .

The second port 28 is a loading port for loading the FOUP 14 similarly to the first port 26 . The FOUP 14 is delivered between the second port 28 and the gripping portion 18 of the first transport cart 4 (or the gripping portion 21 of the second transport cart 6). Then, the semiconductor wafer stored in the FOUP 14 is transferred to and from the semiconductor manufacturing apparatus 8 through the second loading and unloading port 24 .

Furthermore, in the present embodiment, although the semiconductor manufacturing device 8 has two ports (the first port 26 and the second port 28), the present invention is not limited thereto, and it may also have one port. 1 or more ports.

The first communication device 10 is a device server that mediates communication between each of the first transport vehicle 4 and the second transport vehicle 6 and the first port 26 of the semiconductor manufacturing device 8 . The first communication device 10 is disposed, for example, on the top surface of the semiconductor manufacturing device 8 , and is connected to the first port 26 of the semiconductor manufacturing device 8 via a parallel cable 30 . Thereby, the first communication device 10 can perform wired communication with the first port 26 of the semiconductor manufacturing device 8 via the parallel cable 30 . In addition, the first communication device 10 can communicate wirelessly with each of the first transport trolley 4 and the second transport trolley 6 by, for example, short-range wireless communication of Bluetooth Low Energy (BLE, Bluetooth (registered trademark) Low Energy). communication.

The second communication device 12 is a device server for mediating communication between each of the first transport vehicle 4 and the second transport vehicle 6 and the second port 28 of the semiconductor manufacturing device 8 . The second communication device 12 is arranged, for example, on the top surface of the semiconductor manufacturing device 8 and is connected to the second port 28 of the semiconductor manufacturing device 8 via a parallel cable 32 . Thereby, the second communication device 12 can perform wired communication with the second port 28 of the semiconductor manufacturing device 8 via the parallel cable 32 . Also, the second communication device 12 is connected to the first communication device 10 via a serial cable 34 . Thereby, the second communication device 12 can perform wired communication with the first communication device 10 via the serial cable 34 . In addition, the second communication device 12 can perform wireless communication with each of the first transport vehicle 4 and the second transport vehicle 6 by, for example, BLE short-range wireless communication or the like.

Here, for example, a case where the FOUP 14 placed on the first port 26 is loaded by the first transport cart 4 and a case where the FOUP 14 is unloaded from the first transport cart 4 to the first port 26 will be described. In this case, in the above-mentioned wireless communication system 2, control signals (hereinafter also referred to as "communication data") are exchanged between the first transport vehicle 4 and the first communication device 10 through the chain communication of the E84 chain sequence of SEMI. ). In the E84 chain sequence, if the FOUP 14 is transferred between the first transport trolley 4 and the first port 26, as long as the specific control signal (such as L_REQ, U_REQ) is not turned off (off), it will not move to the next One-step chain sequence including multiple steps.

As shown in Figure 2, the E84 chain sequence when loading FOUP 14 is composed of three steps: pre-transfer procedure, transfer procedure and post-transfer procedure. Also, as shown in FIG. 3 , the E84 chain sequence at the time of unloading the FOUP 14 is composed of three steps including a pre-transfer procedure, a transfer procedure, and a post-transfer procedure, as in FIG. 2 . Furthermore, the pre-transfer procedure, the transfer procedure and the post-transfer procedure are, for example, executed in a stopped state at the position immediately above the first port 26 where the FOUP 14 is to be transferred after the first transport trolley 4 arrives. Alternatively, the pre-transfer procedure may be executed while moving (traveling) toward the first port 26 where the FOUP 14 is to be transferred before the first transfer cart 4 reaches the position directly above the first port 26 to transfer the FOUP 14 . In addition, the post-transfer procedure may be performed while moving (moving) the first transport cart 4 away from the position directly above the first port 26 where the FOUP 14 is to be transferred.

As shown in FIG. 2 and FIG. 3 , in the pre-transfer procedure, control signals indicating the contents of starting the transfer of the FOUP 14 are exchanged between the first transport vehicle 4 and the first communication device 10 . In the transfer procedure, control signals for executing the transfer of the FOUP 14 are exchanged between the first transport vehicle 4 and the first communication device 10, and the transfer of the FOUP 14 is actually performed. In the post-transfer procedure, a control signal indicating completion of the transfer of the FOUP 14 is exchanged between the first transport vehicle 4 and the first communication device 10 .

[2. Functional composition of the communication system] The functional configuration of the radio communication system 2 according to the embodiment will be described with reference to FIGS. 4 to 6 . Fig. 4 is a block diagram showing the functional configuration of the wireless communication system 2 of the embodiment. FIG. 5 is a diagram showing an example of the communication framework 42 of chain communication. FIG. 6 is a diagram showing an example of the management table 44 .

As shown in FIG. 4 , the wireless communication system 2 has a first transport vehicle 4 , a second transport vehicle 6 , a first communication device 10 , and a second communication device 12 as functional configurations. Furthermore, the wireless communication system 2 of the present invention is a system for communicating with each of the first port 26 and the second port 28 of the semiconductor manufacturing device 8 .

The first transport vehicle 4 has a communication unit 36 (an example of a first communication unit), a memory unit 38 , and a control unit 40 .

The communication unit 36 transmits and receives communication data of chain communication by wireless communication with the first communication device 10 (or the second communication device 12 ).

Here, as an example, the communication data of the chain communication exchanged between the first transport vehicle 4 and the first communication device 10 will be described. The communication data of the chain communication is, for example, the communication frame 42 shown in FIG. 5 . The communication framework 42 shown in FIG. 5 includes SYNC, Message Length (message length), Message ID (message ID), wireless ID on the transfer trolley side, wireless ID on the semiconductor manufacturing device side, Option/Message Status (option/message status), PI /O IN 8bit, PI/O OUT 8bit, and CHECK SUM (check and) fields.

SYNC is the SYNC part of the communication framework 42 . Message Length is the data length from the Message ID of the communication frame 42 to the PI/O OUT 8bit. Message ID is the unique identification code of the communication framework 42 . The wireless ID on the transport trolley side is the identification information of the first transport trolley 4 . The semiconductor manufacturing device side wireless ID is identification information of the first communication device 10 . Option/Message Status is an option instruction and a transmission direction of the communication frame 42 (first transport vehicle 4→first communication device 10 or first communication device 10→first transport vehicle 4). PI/O IN 8bit is the parallel I/O data input to the first port 26. PI/O OUT 8bit is the parallel I/O data output from the first port 26. CHECK SUM is the CHECK SUM part of the communication framework 42 .

The memory unit 38 is a memory of the memory management table 44 . For example, as shown in FIG. 6, the management table 44 shows the station number of the semiconductor manufacturing device 8, the wireless channel of the first communication device 10, the wireless channel of the second communication device 12, The data table of the corresponding relationship between the device number (identification information) of the communication device 12 and the device number (identification information) of the second communication device 12.

In the example shown in FIG. 6, in the first line of the management table 44, the station number "00001" of the semiconductor manufacturing device 8, the wireless channel "001" of the first communication device 10, and the wireless channel of the second communication device 12 "011", the device number "00001" of the first communication device 10, and the device number "00002" of the second communication device 12 are associated and stored.

The control unit 40 executes various processes by referring to the memory unit 38 and controlling the communication unit 36 . Moreover, the control unit 40 is realized, for example, by a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

The second transport vehicle 6 has a communication unit 46 (an example of the first communication unit), a memory unit 48 , and a control unit 50 .

The communication unit 46 transmits and receives communication data of chain communication by wireless communication with the first communication device 10 (or the second communication device 12 ).

The storage unit 48 is a memory for storing the above-mentioned management table 44 .

The control unit 50 executes various processes by referring to the memory unit 48 and controlling the communication unit 46 . Moreover, the control unit 50 is realized, for example, by a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

The first communication device 10 includes a communication unit 52 (an example of a second communication unit) and a control unit 54 .

The communication part 52 transmits and receives the communication data of chain communication by wireless communication with each of the 1st conveyance cart 4 and the 2nd conveyance cart 6. Also, the communication unit 52 transmits and receives communication data to and from the first port 26 via the parallel cable 30 . Furthermore, the communication unit 52 transmits and receives various data to and from the second communication device 12 via the serial cable 34 .

The control unit 54 executes various processes by controlling the communication unit 52 . Furthermore, the control unit 54 is realized by, for example, a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

The second communication device 12 has a communication unit 56 (an example of a second communication unit) and a control unit 58 .

The communication part 56 transmits and receives the communication data of chain communication by wireless communication with each of the 1st conveyance cart 4 and the 2nd conveyance cart 6. Also, the communication unit 56 transmits and receives communication data to and from the second port 28 via the parallel cable 32 . Furthermore, the communication unit 56 transmits and receives various data to and from the first communication device 10 via the serial cable 34 .

The control unit 58 executes various processes by controlling the communication unit 56 . Furthermore, the control unit 58 is realized, for example, by a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

The first port 26 has a communication unit 60 and a control unit 62 .

The communication unit 60 transmits and receives communication data to and from the first communication device 10 via the parallel cable 30 .

The control unit 62 executes various processes by controlling the communication unit 60 . Specifically, the control unit 62 executes a chain process for transferring the FOUP 14 between each of the first transport cart 4 and the second transport cart 6 based on the communication data from the first communication device 10 . In addition, the control unit 62 executes a process for transferring the FOUP 14 to and from the semiconductor manufacturing apparatus 8 through the first loading/unloading port 22 . Furthermore, the control unit 62 is realized, for example, by a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

The second port 28 has a communication unit 64 and a control unit 66 .

The communication unit 64 transmits and receives communication data to and from the second communication device 12 via the parallel cable 32 .

The control unit 66 executes various processes by controlling the communication unit 64 . Specifically, the control unit 66 executes a chain process for transferring the FOUP 14 between each of the first transport cart 4 and the second transport cart 6 based on the communication data from the second communication device 12 . Furthermore, the control unit 66 executes a process for transferring the FOUP 14 to and from the semiconductor manufacturing apparatus 8 through the second loading/unloading port 24 . Furthermore, the control unit 66 is realized, for example, by a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory.

[3. Operation of wireless communication system] The operation of the wireless communication system 2 will be described with reference to FIGS. 7 and 8 . FIG. 7 is a diagram for explaining the operation of the radio communication system 2 according to the embodiment. Fig. 8 is a sequence diagram showing the flow of operations of the wireless communication system 2 according to the embodiment.

Hereinafter, as shown in FIG. 7, a case where semiconductor manufacturing apparatuses 8a, 8b, 8c, and 8d are sequentially arranged in a semiconductor manufacturing factory will be considered.

The semiconductor manufacturing device 8a has a first port 26a and a second port 28a. The first communication device 10a and the second communication device 12a are respectively connected to the first port 26a and the second port 28a.

The semiconductor manufacturing device 8b has a first port 26b and a second port 28b. The first communication device 10b and the second communication device 12b are connected to the first port 26b and the second port 28b, respectively.

The semiconductor manufacturing device 8c has a first port 26c and a second port 28c. The first communication device 10c and the second communication device 12c are respectively connected to the first port 26c and the second port 28c.

The semiconductor manufacturing apparatus 8d has a first port 26d and a second port 28d. The first communication device 10d and the second communication device 12d are connected to the first port 26d and the second port 28d, respectively.

In addition, it will be described below that the first transport trolley 4 and the second transport trolley 6 transfer FOUPs between the first port 26b of the semiconductor manufacturing apparatus 8b and the first port 26b of the semiconductor manufacturing apparatus 8b under instructions from a host controller (not shown) at approximately the same time point. 14 (see Figure 1). In this case, the first transport trolley 4 and the second transport trolley 6 move along the first rail 16 and the second rail 20 respectively, and at approximately the same time point, they are in front of the first port 26b where the FOUP 14 is to be transferred. The upper position stops. In addition, the first transport trolley 4 and the second transport trolley 6 acquire information related to the first communication device 10b connected to the first port 26b (such as the wireless frequency band, wireless channel, and wireless ID of the first communication device 10b) from the host controller. Wait). Thereby, each of the 1st conveyance vehicle 4 and the 2nd conveyance vehicle 6 can perform wireless communication with the 1st communication device 10b based on the acquired information about the 1st communication device 10b.

As shown in FIG. 8, the communication part 36 of the 1st conveyance vehicle 4 transmits the pairing signal for communication synchronization to the 1st communication device 10b by wireless communication (S101). When the first communication device 10b receives the pairing signal as a trigger, the communication unit 36 of the first transport vehicle 4 sends a command signal (an example of the first communication data) as communication data of chain communication to the first communication device 4 through wireless communication. The communication device 10b (S102). Here, the communication part 36 of the 1st conveyance vehicle 4 transmits a command signal to the 1st communication device 10b at a predetermined cycle (for example, 10 msec). Furthermore, the time point as the starting point of the predetermined cycle may be the time point when the command signal is sent in step S102, or the time point when the pairing signal is sent in step S101.

The communication part 52 of the 1st communication device 10b receives the command signal from the 1st conveyance vehicle 4 by wireless communication. Furthermore, the communication unit 52 of the first communication device 10b transmits (outputs) the received command signal to the first port 26b through wired communication. The communication unit 52 of the first communication device 10b transmits the communication data of the chain communication, that is, the response signal (an example of the second communication data), as a response to the received command signal, to the first transport trolley 4 through wireless communication. (S103). Here, the communication unit 52 of the first communication device 10 b transmits a response signal to the first transport vehicle 4 every time it receives a command signal from the first transport vehicle 4 .

In this way, the command signal from the first transport trolley 4 is received by the first communication device 10b, and the response signal from the first communication device 10b is received by the first transport trolley 4, thereby, on the first transport trolley 4 Chain communication is established with the first communication device 10b. Thereby, between the first transfer trolley 4 and the first port 26b, the pre-transfer procedure, the transfer procedure, and the post-transfer procedure are sequentially executed through the E84 chain sequence.

Next, the communication unit 36 of the first transport vehicle 4 receives the response signal from the first communication device 10b, and in response thereto, transmits a command signal to the first communication device 10b by wireless communication (S104). Similar to the above, the communication unit 52 of the first communication device 10b receives a command signal from the first transport vehicle 4 through wireless communication. In addition, the communication unit 52 of the first communication device 10b outputs the received command signal to the first port 26b through wired communication.

Next, the communication part 46 of the 2nd conveyance vehicle 6 transmits the pairing signal for communication synchronization to the 1st communication device 10b by wireless communication (S105). The first communication device 10b receives the pairing signal as a trigger, and the communication unit 46 of the second transport vehicle 6 sends a command signal to the first communication device 10b through wireless communication (S106). Here, the communication part 46 of the 2nd conveyance vehicle 6 transmits a command signal to the 1st communication device 10b at a predetermined cycle (for example, 10 msec). The predetermined period of the command signal sent by the communication unit 36 of the first transport vehicle 4 is the same as the predetermined period of the command signal transmitted by the communication unit 46 of the second transport vehicle 6 . Furthermore, the time point as the starting point of the predetermined period may be the time point when the instruction signal is sent in step S106, or the time point when the pairing signal is sent in step S105.

At the same point in time as the above step S106, the communication unit 52 of the first communication device 10b transmits a response signal to the second transport vehicle 6 through wireless communication as a response to the command signal from the first transport vehicle 4 (S107) , and send a response signal to the first transport vehicle 4 (S108). Furthermore, the time points of these steps S107 and S108 may also be approximately at the same time.

At this time, the time point when the second transport vehicle 6 sends the command signal in step S106 coincides with the time point when the first communication device 10b sends the response signal in step S107, so the command signal and the response signal conflict (S109). Therefore, the communication unit 46 of the second transport vehicle 6 cannot receive the signal sent in step S107 due to the conflict between the signals (command signal and response signal) in step S109 (more specifically, the damage of the two communication frames). Therefore, interlock communication is not established between the second transport vehicle 6 and the first communication device 10b. On the other hand, the communication unit 36 of the first transport vehicle 4 does not transmit the command signal when the first communication device 10b transmits the response signal, so the command signal and the response signal do not conflict. Therefore, the communication unit 36 of the first transport vehicle 4 can receive the response signal transmitted in step S108.

Next, the communication unit 36 of the first transport vehicle 4 receives the response signal from the first communication device 10b, and in response thereto, transmits a command signal to the first communication device 10b by wireless communication (S110). When the communication unit 46 of the second transport trolley 6 still cannot receive the response signal within a predetermined time (for example, 100 msec) after sending the command signal in step S106, it will send the command signal following the command signal sent in step S106. The time point of the transmitted command signal is changed from the time point according to the predetermined cycle (the time point indicated by the dotted arrow in FIG. 8 ) (S111).

Specifically, the communication unit 46 of the second transport vehicle 6 makes the instruction signal sent in step S106 to send the instruction after a delay of less than 10 msec (for example, 7 msec) from the time point that should have been sent. The time points of the signals are staggered. Thereby, the communication part 46 of the 2nd conveyance vehicle 6 transmits a command signal to the 1st communication device 10b at this changed time point (S112). At this time, the communication unit 46 of the second transport vehicle 6 does not change the predetermined cycle of transmitting the command signal. In addition, the amount of shift at this point in time does not have to be a fixed value, and may be a different value determined in advance for the first transport cart 4 and the second transport cart 6 . Alternatively, the staggered amount of the time point may also be randomly determined.

Furthermore, in the above-mentioned step S111, the communication unit 46 of the second transport trolley 6 can also delay the time (for example, 12 msec) longer than 10 msec from the time point that should have been sent, so that the command signal sent in the step S106 is followed up. The timing of sending command signals is staggered.

Also, before changing the time point in step S111, the time point at which the second transport trolley 6 should have sent the command signal (the time point indicated by the dotted arrow in FIG. The point in time becomes consistent. In this case, as mentioned above, by changing the time point of sending the command signal in step S111, then thereafter, the time point when the first transport trolley 4 sends the command signal and the time point when the second transport trolley 6 sends the command signal become inconsistent . As a result, a conflict between the command signal from the first transport cart 4 and the command signal from the second transport cart 6 can be avoided.

The communication unit 52 of the first communication device 10b then receives: the command signal from the first transport trolley 4 sent in step S110 and the command signal from the second transport trolley 6 sent at a staggered time point in step S112.

At this time, the communication unit 52 of the first communication device 10b transmits the command signal from the first transport vehicle 4 with which chain communication has been established with the first communication device 10b to the first port 26b through wired communication.

On the other hand, the communication unit 52 of the first communication device 10b cancels the command signal from the second transport vehicle 6 that has not established chain communication with the first communication device 10b (S113). Thereby, the communication unit 52 of the first communication device 10b is during the chain communication period established between the first transport trolley 4, when receiving the communication from other transport trolleys (the second transport trolley 6) other than the first transport trolley 4 When the command signal is received, the received command signal will not be sent to the first port 26b. That is, the communication unit 52 of the first communication device 10b can avoid communication with other transport carts (the second transport cart 6) other than the first transport cart 4 during the period when the chain communication has been established with the first transport cart 4. ) to establish chain communication.

The communication unit 52 of the first communication device 10b transmits a response signal to the first transport trolley 4 through wireless communication as a response to the command signal from the first transport trolley 4 (S114), and sends the response signal to the second transport trolley 4. Trolley 6 (S115). Furthermore, the time points of these steps S114 and S115 may also be approximately at the same time.

The communication unit 36 of the first transport trolley 4 receives the response signal from the first communication device 10b, and thereafter, continues chain communication with the first communication device 10b until E84 between the first transport trolley 4 and the first port 26b. After the transfer of the chain sequence, the program ends. Furthermore, the communication unit 36 of the first transport trolley 4 transmits the communication frame 42 of FIG. 5 including PI/O IN 8bit (all 0) and PI/O OUT 8bit (all 0) to the first communication device 10b, And the chain communication with the first communication device 10b ends.

On the other hand, the communication unit 46 of the second transport vehicle 6 receives the response to the command signal from the first transport vehicle 4, that is, the response signal transmitted by the first communication device 10b in step S115. At this time, the communication unit 46 of the second transport vehicle 6 uses the wireless ID on the transport vehicle side (identification information of the first transport vehicle 4 ) and the wireless ID on the semiconductor manufacturing device side shown in FIG. 5 contained in the received response signal. identification information of the first communication device 10b), and it is determined that chain communication has been established between the first transport trolley 4 and the first communication device 10b. The communication part 46 of the 2nd conveyance vehicle 6 stops transmission of a command signal to the 1st communication device 10b based on this determination result (S116).

Next, the communication unit 46 of the second transport vehicle 6 reads out the wireless channel and device number (identification information) of the second communication device 12b connected to the first communication device 10b by referring to the management table 44 stored in the storage unit 48. ). The communication unit 46 of the second transport vehicle 6 transmits an inquiry signal to the second communication device 12b through wireless communication based on the read wireless channel and device number of the second communication device 12b (S117). The inquiry signal is a signal for inquiring the second communication device 12b about the progress status of the chain communication between the first transport vehicle 4 and the first communication device 10b.

The communication part 56 of the 2nd communication device 12b receives the inquiry signal from the 2nd conveyance vehicle 6, Correspondingly, it transmits the request signal to the 1st communication device 10b by wired communication (S118). The request signal is a signal for requesting the first communication device 10b to transmit information on the progress status of the chain communication between the first transport vehicle 4 and the first communication device 10b (hereinafter referred to as "progress status information").

The communication unit 52 of the first communication device 10b receives the request signal from the second communication device 12b, and in response thereto, transmits a response signal to the second communication device 12b through wired communication (S119). The response signal is a signal for transmitting progress status information in response to a request signal from the second communication device 12b. Moreover, the progress status information can be obtained from the PI/O IN 8bit and PI/O OUT 8bit contained in the communication frame 42 shown in FIG. 5 .

The communication unit 56 of the second communication device 12b receives the response signal from the first communication device 10b, and in response thereto, transmits the response signal to the second transport vehicle 6 through wireless communication (S120). The reply signal is a signal for sending progress status information in reply to the inquiry signal from the second transport vehicle 6 .

The communication unit 46 of the second transport vehicle 6 receives the response signal from the second communication device 12b. The control unit 50 of the second transport vehicle 6 judges the progress status of the chain communication between the first transport vehicle 4 and the first communication device 10b based on the response signal received by the communication unit 46 (S121). The control part 50 of the 2nd conveyance vehicle 6 executes any one of the following 1st control and 2nd control according to the progress state of the interlocking communication shown by a reply signal.

When the progress status of the chain communication between the first transport trolley 4 and the first communication device 10b is the situation before the transfer ("before transfer procedure" in S121), the control part 50 of the second transport trolley 6 executes the first 1 control (S122). In the first control, the control unit 50 of the second transport cart 6 moves the second transport cart 6 away from the position immediately above the first port 26b, and controls the second transport cart 6 to move in a detour.

When the FOUP 14 is unloaded from the second transport trolley 6 to the first port 26b, the control unit 50 of the second transport trolley 6 controls the movement of the second transport trolley 6 so that it is between the first transport trolley 4 and the first communication device 10b. After inter-chain communication ends, return to the position directly above the first port 26b again. When the second transport trolley 6 returns to the position directly above the first port 26b again, the control unit 50 of the second transport trolley 6 controls the communication unit 46 to send a pairing signal to the first communication device 10b.

On the other hand, as in the case of loading the FOUP 14 from the first port 26b to the second transport trolley 6, the control unit 50 of the second transport trolley 6 controls the movement of the second transport trolley 6 so that it is placed on the first transport trolley 4. After the chain communication with the first communication device 10b ends, it returns to the position directly above the first port 26b again. Furthermore, in this case, it is also possible to replace the second transport trolley 6 with other transport trolleys except the first transport trolley 4 and the second transport trolley 6, and between the first transport trolley 4 and the first communication device After the chain communication between 10b ends, it arrives at the position directly above the first port 26b.

When the progress status of the chain communication between the first transport vehicle 4 and the first communication device 10b is the pre-transfer procedure, it takes a relatively long time (for example, 10 seconds) until the chain communication ends. In this case, by performing the first control of making the second transport trolley 6 detour, it is possible to prevent the second transport trolley 6 from interfering with the subsequent movement of other transport trolleys in the second rail 20, thereby preventing the transport trolleys from There is a traffic jam.

On the other hand, when the progress status of the chain communication between the first transport trolley 4 and the first communication device 10b is the post-transfer procedure ("post-transfer procedure" in S121), the control unit 50 of the second transport trolley 6 Then, the second control is executed (S123). In the second control, the control unit 50 of the second transport trolley 6 controls the communication unit 46 so that the second transport trolley 6 waits at the position directly above the first port 26b until the chain communication ends, and after the chain communication ends, A pairing signal is sent to the first communication device 10b.

When the progress status of the chain communication between the first transport vehicle 4 and the first communication device 10b is the post-transfer process, a relatively short time (for example, 1 second) is required until the chain communication ends. In this case, by executing the second control of making the second transport vehicle 6 stand by there, the second transport vehicle 6 can promptly send a pairing signal to the first communication device 10b after the chain communication is completed.

Also, when the progress status of the chain communication between the first transport trolley 4 and the first communication device 10b is the transfer procedure ("transfer procedure" in S121), the control unit 50 of the second transport trolley 6 starts the transfer process. After the program, it is judged whether or not a predetermined time T (for example, several seconds) has elapsed (S124). When the predetermined time T has not passed (NO in S124), the control unit 50 of the second transport vehicle 6 executes the above-mentioned first control (step S122). In this case, it takes a relatively long time until the end of the chain communication, so by performing the first control that makes the second conveying cart 6 detour, it is possible to avoid the second conveying cart 6 in the second track 20. It hinders the subsequent movement of other transport trolleys, so as to avoid traffic jams in the transport trolleys.

On the other hand, when the predetermined time T has elapsed (YES in S124), the control unit 50 of the second transport vehicle 6 executes the above-mentioned second control (step S123). In this case, it takes a relatively short time until the end of the chain communication, so by executing the second control that makes the second transport trolley 6 stand by there, the second transport trolley 6 can finish the chain communication. The pairing signal is promptly sent to the first communication device 10b.

[4. Effect] FIG. 9 is a sequence diagram showing the flow of operations of the radio communication system of the comparative example. In the sequence diagram of FIG. 9 , the same processes as those in the sequence diagram of FIG. 8 are assigned the same step numbers, and their descriptions are omitted.

In the wireless communication system of the comparative example, step S111 in FIG. 8 is not executed after steps S101 to S110 are executed. As shown in Figure 9, after step S109, the communication unit 36 of the first transport trolley 4 sends the command signal to the first communication device 10b (S110), and at the same time point, the communication unit 36 of the second transport trolley 6 46 transmits a command signal to the first communication device 10b (S201). That is, the period and timing at which the communication unit 36 of the first transport vehicle 4 transmits the command signal coincides with the period and timing at which the communication unit 46 of the second transport vehicle 6 transmits the command signal. In this case, because the command signal from the first transport trolley 4 conflicts with the command signal from the second transport trolley 6 (S202), the communication unit 52 of the first communication device 10b cannot receive the command signal, resulting in a communication error .

Thereafter, in the same manner as above, the communication unit 36 of the first transport vehicle 4 retransmits the command signal to the first communication device 10b (S203), and at the same point in time, the communication unit 46 of the second transport vehicle 6 sends The command signal is sent again to the first communication device 10b (S204). In this case, also because the command signal from the first transport trolley 4 conflicts with the command signal from the second transport trolley 6 (S205), so the communication unit 52 of the first communication device 10b cannot receive the command signal and cause communication. mistake.

When the communication unit 36 of the first transport vehicle 4 fails to receive a response signal within a predetermined response time (for example, 250 msec) after sending the command signal, a communication timeout occurs (S206). Similarly, after the communication unit 46 of the second transport vehicle 6 sends the command signal, when the response signal cannot be received within the predetermined response time (for example, 250 msec), a communication timeout occurs (S207). Therefore, both the first transport vehicle 4 and the second transport vehicle 6 have a problem that chain communication with the first communication device 10b cannot be performed.

In contrast, in the present embodiment, when the communication unit 46 of the second transport trolley 6 cannot receive the response signal after a predetermined time has elapsed after sending the command signal in step S106 of FIG. The time point of the command signal sent after the command signal sent in step S106 is changed from the time point according to the predetermined cycle (the time point indicated by the dotted arrow in FIG. 8 ).

In this way, even if the predetermined cycle of the communication part 36 of the first transport trolley 4 to send the command signal is consistent with the predetermined cycle of the communication part 46 of the second transport trolley 6 to send the command signal, it can also be avoided. The command signal from the trolley 4 conflicts with the command signal from the second transport trolley 6 . As a result, the communication unit 52 of the first communication device 10b can receive the command signal, so it does not cause a communication error, and the first transport vehicle 4 can continue to perform chain communication with the first communication device 10b.

(Other modified examples, etc.) As mentioned above, although the radio communication system and the control method of the radio communication system of this invention were demonstrated based on the said embodiment, this invention is not limited to the said embodiment. The forms obtained by the changes conceivable by those with ordinary knowledge in the field of the present invention to the above-mentioned embodiments, and other forms realized by any combination of the constituent elements in the above-mentioned embodiments are also included in the present invention.

In the above-mentioned embodiment, although the first rail 16 and the second rail 20 are arranged at different positions in the vertical direction directly above the first port 26 of the semiconductor manufacturing device 8, the present invention is not limited thereto. For example, the first rail 16 and the second rail 20 may be arranged at different positions in the horizontal direction perpendicular to the respective extending directions of the first rail 16 and the second rail 20 . In this case, both the first transport trolley 4 on the first track 16 and the second transport trolley 6 on the second track 20 can transfer the FOUP 14 between the first port 26 and the like, so it is the same as the above embodiment. Likewise, the effects of the present invention can be exhibited.

Alternatively, the first transport trolley 4 and the second transport trolley 6 may travel two-dimensionally along a plurality of rails arranged in a grid pattern in the horizontal plane. In this case, the first transport trolley 4 and the second transport trolley 6 can move the FOUP between the first port 26 and the like at the first position and the second position which are different from each other on a plurality of grid-shaped rails. 14. Therefore, it can exhibit the effects of the present invention in the same manner as the above-mentioned embodiments.

Furthermore, in the above-mentioned embodiments, each constituent element can also be realized by configuring dedicated hardware, or by executing a software program suitable for each constituent element. Each constituent element can also be realized by reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory by a program execution unit such as a central processing unit (CPU) or a processor. (industrial availability)

The wireless communication system of the present invention can be applied, for example, to a semiconductor manufacturing system in which FOUPs are transported by a transport cart moving along a rail provided on a ceiling.

2: Wireless communication system 4: The first transport trolley 6: The second transport trolley 8, 8a, 8b, 8c, 8d: Semiconductor manufacturing equipment 10, 10a, 10b, 10c, 10d: first communication device 12, 12a, 12b, 12c, 12d: the second communication device 14:FOUP 16: Track 1 18,21: Gripping part 20: Track 2 22: The first import and export port 24: The second import and export port 26,26a,26b,26c,26d: port 1 28,28a,28b,28c,28d: port 2 30,32: parallel cable 34: Serial cable 36,46,52,56,60,64: Department of Communications 38,48: memory department 40,50,54,58,62,66: control department 42:Communication Framework 44: Management table

FIG. 1 is a diagram showing an outline of a radio communication system according to an embodiment. Fig. 2 is a diagram showing an example of E84 chain sequence when FOUP is loaded. Fig. 3 is a diagram showing an example of E84 chain sequence when FOUP is unloaded. Fig. 4 is a block diagram showing the functional configuration of the wireless communication system of the embodiment. FIG. 5 is a diagram showing an example of a communication framework of chain communication. FIG. 6 is a diagram showing an example of a management table. Fig. 7 is a diagram for explaining the operation of the wireless communication system according to the embodiment. Fig. 8 is a sequence diagram showing the flow of operations of the wireless communication system according to the embodiment. FIG. 9 is a sequence diagram showing the flow of operations of the radio communication system of the comparative example.

4: The first transport trolley

6: The second transport trolley

10b: the first communication device

12b: The second communication device

Claims (10)

A wireless communication system comprising: a plurality of conveyance carts that convey objects to be conveyed by moving along rails; and a communication device connected to the conveyance objects that are transferred by each of the plurality of conveyance carts port of things, and perform wireless communication with each of the above-mentioned plurality of transfer trolleys; wherein, Each of the above-mentioned plurality of transport vehicles has a first communication part, and the first communication part is: (i) sending a pairing signal to the above-mentioned communication device, (ii) when the above-mentioned communication device receives the above-mentioned pairing signal as a trigger, Sending the first communication data of the chain communication for transferring the object to the port to the communication device, and receiving the second communication data of the chain communication from the communication device as a response to the first communication data , thereby establishing the above-mentioned chain communication with the above-mentioned communication device, The above-mentioned communication device has a second communication unit, and the second communication unit is: (iii) receiving the above-mentioned pairing signal from a specific transport trolley among the above-mentioned plurality of transport trolleys, (iv) when receiving the above-mentioned pairing signal as a trigger, receiving The above-mentioned first communication data of the above-mentioned specific transport trolley, and whenever the above-mentioned first communication data is received, the above-mentioned second communication data is sent to the above-mentioned specific transport trolley, thereby communicating with the above-mentioned specific transport trolley Establish the above-mentioned chain communication, (v) avoid establishing the above-mentioned chain communication with other transport vehicles other than the above-mentioned specific transport vehicle during the period of establishing the above-mentioned chain communication with the above-mentioned specific transport vehicle, The above-mentioned first communication department shall send the first communication data sent after the first communication data when the above-mentioned second communication data cannot be received after a predetermined time elapses after sending the above-mentioned first communication data to the above-mentioned communication device. The time point of the communication data is changed from the time point according to the above-mentioned predetermined cycle. The wireless communication system according to claim 1, wherein, The first communication unit of the other transport vehicle does not transmit the first communication data when receiving the second communication data of the chain communication established between the specific transport vehicle and the communication device. to the aforementioned communication device. The wireless communication system according to claim 1 or 2, wherein, When the above-mentioned first communication unit of the above-mentioned other transportation vehicle receives the above-mentioned second communication data of the above-mentioned chain communication established between the above-mentioned specific transportation vehicle and the above-mentioned communication device, according to the information contained in the second communication data, The identification information of the above-mentioned communication device and the identification information of the above-mentioned specific transport trolley, and it is determined that the above-mentioned chain communication is established between the above-mentioned communication device and the above-mentioned specific transport trolley. The wireless communication system according to any one of claims 1 to 3, wherein, The above-mentioned second communication unit of the above-mentioned communication device, when receiving the above-mentioned first communication data from the above-mentioned other transportation vehicles during the period when the above-mentioned chain communication is established with the above-mentioned specific transportation vehicles, does not The first communication data is output to the port. The wireless communication system according to any one of claims 1 to 4, wherein, Each of the plurality of transport vehicles further includes a control unit, The aforementioned control unit of the aforementioned other transport trolley executes any one of the first control and the second control when the aforementioned chain communication is established between the aforementioned communication device and the aforementioned specific transport trolley; The control system moves the other transport trolleys to leave the port; the second control system controls the first communication unit so that the other transport trolleys are kept on standby until the chain communication ends, and the other transport carts are used after the chain communication ends. The pairing signal is sent to the communication device. As the wireless communication system of claim 5, wherein, The control unit of the other transport vehicle executes either of the first control and the second control based on the progress status of the chain communication between the communication device and the specific transport vehicle. The wireless communication system according to any one of claims 1 to 6, wherein, The above-mentioned rails include a first rail and a second rail arranged at different positions in the vertical direction, The above-mentioned specified transport trolley and the above-mentioned other transport trolleys can transfer the above-mentioned conveyed objects between the above-mentioned ports on the above-mentioned first rail and the above-mentioned second rail, respectively. The wireless communication system according to any one of claims 1 to 6, wherein, The track includes a first track and a second track arranged at different positions in a horizontal direction perpendicular to the extending direction of the track, The above-mentioned specified transport trolley and the above-mentioned other transport trolleys can transfer the above-mentioned conveyed objects between the above-mentioned ports on the above-mentioned first rail and the above-mentioned second rail, respectively. The wireless communication system according to any one of claims 1 to 6, wherein, The above track includes a plurality of tracks arranged in a grid pattern in the horizontal plane, The above-mentioned specific transport trolley and the above-mentioned other transport trolleys can transfer the above-mentioned conveyed objects between the above-mentioned ports at the first position and the second position which are different from each other on the plurality of rails. A control method of a wireless communication system, the wireless communication system is provided with: a plurality of transport carts, which transport objects to be transported by moving along rails; and a communication device connected to each of the plurality of transport carts And the port where the above-mentioned conveyed object is transferred performs wireless communication with each of the above-mentioned plurality of conveying trolleys; the control method of the wireless communication system includes the following steps: (a) the step of sending a pairing signal to the above-mentioned communication device by a specific transport trolley among the above-mentioned plurality of transport trolleys; (b) The above-mentioned communication device receives the above-mentioned pairing signal from the above-mentioned specific transport trolley; (c) When the communication device receives the pairing signal as a trigger, the specific transport trolley sends to the communication device the first communication data of chain communication for transferring the transported object to the port at a predetermined period, and Whenever the above-mentioned communication device receives the above-mentioned first communication data, it sends the second communication data of the above-mentioned chain communication to the above-mentioned specific transport trolley as a response to the above-mentioned first communication data, whereby the above-mentioned specific transport trolley The step of establishing the above-mentioned chain communication with the above-mentioned communication device; (d) When the above-mentioned specific transport vehicle cannot receive the above-mentioned second communication data after a predetermined period of time after sending the above-mentioned first communication data to the above-mentioned communication device, it will send the information sent after the first communication data. Steps for changing the time point of the first communication data from the time point according to the above-mentioned predetermined cycle; and (e) A step of avoiding establishing the chain communication with other transport vehicles other than the specific transport vehicle while the communication device is establishing the chain communication with the specific transport vehicle.

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