Goods handling equipment

Abstract

To provide article transportation equipment capable of keeping a satisfactory communication state between a control device and a transportation vehicle.SOLUTION: A control device 2 and a transportation vehicle 1 are capable of bidirectional communication via one of a plurality of access points AP. When communication from the transportation vehicle 1 to the control device 2 is interrupted, the control device 2 transmits a command Co for communication restoration to the transportation vehicle 1, on the presumption that communication from the control device 2 to the transportation vehicle 1 is effective.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to article conveying equipment provided with: a conveying vehicle that moves along a prescribed route to convey articles; a control device that controls the conveying vehicle; and a plurality of access points each performing wireless communication with the conveying vehicle.

Background Art

[0002] An example of such article conveying equipment is disclosed in Japanese Patent Laid-Open No. 2011-166671 (Patent Document 1). Hereinafter, reference numerals shown in parentheses in the description of the background art are those from Patent Document 1.

[0003] In the equipment described in Patent Document 1, control devices (18, 20) such as a server and a plurality of conveying vehicles (12) are connected via a wireless LAN and configured to communicate with each other. Accordingly, the control devices (18, 20) can grasp the current position of the conveying vehicle (12) and issue commands such as a conveyance command to the conveying vehicle (12) via wireless communication.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] In the equipment described in Patent Document 1, since wireless communication is used for communication between the control devices (18, 20) and the conveying vehicle (12), poor communication may occur depending on abnormalities of communication equipment, the surrounding environment, or other factors. Although it is not always possible to identify the cause of poor communication, when poor communication occurs, it is preferable to take some measure to improve the communication state.

[0006] In light of the above circumstances, there is a need for the realization of an item handling system that can maintain good communication between the control device and the transport vehicle. [Means for solving the problem]

[0007] A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The control device and the transport vehicle are configured to communicate bidirectionally via one of the multiple access points. The control device will be affected if communication from the transport vehicle to the control device is interrupted. Therefore, information cannot be obtained from the aforementioned transport vehicle. In that case, the communication from the control device to the transport vehicle is considered valid, and a command for restoring communication is sent to the transport vehicle.

[0008] In a configuration where the control device and the transport vehicle communicate bidirectionally, even if communication from the transport vehicle to the control device is interrupted, communication from the control device to the transport vehicle is not necessarily impossible. According to this configuration, if communication from the transport vehicle to the control device is interrupted, the control device assumes that communication from the control device to the transport vehicle is still valid and sends a command to the transport vehicle to restore communication. If communication from the control device to the transport vehicle is still valid, the command will reach the transport vehicle, and the command will cause the transport vehicle to perform an action to restore communication. Therefore, this configuration makes it possible to maintain good communication between the control device and the transport vehicle.

[0009] Other goods handling equipment includes: A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The control device and the transport vehicle are configured to communicate bidirectionally via one of the multiple access points. If communication from the transport vehicle to the control device is interrupted, the control device will assume that communication from the control device to the transport vehicle is still valid and will send a command to the transport vehicle to restore communication. The control device is configured to repeatedly transmit a confirmation signal to the transport vehicle at a set interval. The transport vehicle is configured to transmit a receipt signal to the control device in response to receiving the confirmation signal. If the control device does not receive the reception signal from the transport vehicle for a predetermined set period, it executes a period change process to shorten the set period.

[0010] Further features and advantages of the technology according to the present disclosure will become more apparent from the following description of exemplary and non-limiting embodiments described with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] [Figure 1] Plan view of article conveyance equipment [Figure 2] Control block diagram [Figure 3] Conceptual diagram showing a communication configuration [Figure 4] Diagram showing access point switching based on a point switching command [Figure 5] Diagram showing movement of a conveyance vehicle based on a movement command [Figure 6] Diagram showing a cycle in which confirmation signals are transmitted [Figure 7] Diagram showing information stored when a communication failure vehicle is identified DESCRIPTION OF EMBODIMENTS

[0012] Hereinafter, an embodiment of article conveyance equipment will be described with reference to the drawings.

[0013] As shown in Fig. 1, the article conveyance equipment 100 includes a conveyance vehicle 1 that moves along a predetermined route 8 to convey an article (not shown), and a control device 2 that controls the conveyance vehicle 1 (see Fig. 2 and the like).

[0014] As shown in Fig. 3, in the present embodiment, the route 8 is configured using a rail 80 installed near the ceiling. The conveyance vehicle 1 is configured as a so-called overhead conveyance vehicle that travels while being supported by such a rail 80. In the present embodiment, the conveyance vehicle 1 includes a main body section 10, a traveling section 11 that travels along the rail 80, and a holding section 12 that holds an article. The main body section 10 is configured to be able to accommodate the holding section 12 and the article held by the holding section 12.

[0015] As shown in Figure 1, in this embodiment, the goods transport equipment 100 includes a plurality of transfer target locations 9 provided along the path 8. The transfer target locations 9 are located below the path 8. In this example, the path 8 includes an interbay and a plurality of intrabays connected to the interbay. Each intrabay is provided with a plurality of transfer target locations 9. The interbay can be described as the movement area where the transport vehicle 1 primarily moves. The intrabay can be described as the transfer area where the transport vehicle 1 primarily performs the transfer of goods. The transport vehicle 1 is configured to transfer goods between the transfer target location 9 and the transfer target location by raising and lowering the holding section 12 (see Figure 3).

[0016] In this embodiment, the goods transport equipment 100 is equipped with multiple transport vehicles 1. Each of the multiple transport vehicles 1 is configured to receive a transport command from a control device 2 (see Figure 2, etc.) and to perform a task corresponding to the transport command. For example, the transport command includes information about the source and destination of the goods. A transport vehicle 1 that receives a transport command transports the goods from the source to the destination. The source and destination include the transfer target location 9.

[0017] Various items can be handled by the item handling equipment 100. In this example, the item handling equipment 100 is used in a semiconductor manufacturing plant. Therefore, items include substrate containers (so-called FOUPs: Front Opening Unified Pods) that house substrates (wafers, panels, etc.) and reticle containers (so-called reticle pods) that house reticles. In this case, the transport vehicle 1 transports items such as substrate containers and reticle containers along the route 8 between each process.

[0018] In this embodiment, the transfer target location 9 comprises a processing device 90 that performs processing on an article, and a mounting table 91 positioned adjacent to the processing device 90. In this specification, "processing on an article" means processing on the contents (substrates or reticles) contained in the article, which serves as a container. The transport vehicle 1 receives articles that have been processed by the processing device 90 from the mounting table 91, or hands over articles that have not yet been processed by the processing device 90 to the mounting table 91. The processing apparatus 90 performs various processes, such as thin film formation, photolithography, and etching.

[0019] As shown in Figure 2, the goods transport equipment 100 is equipped with multiple access point APs (only one access point AP is shown in Figure 2), each of which communicates wirelessly with the transport vehicle 1. An access point AP is positioned in the center of each of the multiple circular areas shown in Figure 1. These circular areas indicate the approximate communication range of each access point AP. However, this is only an estimate, and communication may be possible even outside the circular areas.

[0020] The control device 2 and the transport vehicle 1 are configured to communicate bidirectionally via one of several access points AP. As will be described in detail later, the control device 2 is configured to repeatedly transmit a confirmation signal Sc to the transport vehicle 1 at a set period C (see Figure 6). The transport vehicle 1 is configured to transmit a receipt signal Sr to the control device 2 in response to receiving the confirmation signal Sc. With this configuration, the control device 2 can periodically check the communication status with the transport vehicle 1.

[0021] In this embodiment, the control device 2 comprises a processing unit 20 and a storage unit 21. The processing unit 20 is configured using an arithmetic processing unit such as a CPU (Central Processing Unit). The storage unit 21 is configured using a storage device that can be accessed by the arithmetic processing unit, such as RAM (Random Access Memory) or ROM (Read Only Memory). The various functions of the control device 2 are powered by software (programs) stored in the storage unit 21, hardware such as separately provided arithmetic circuits, or both. The processing unit 20 of the control device 2 operates as a computer that executes each program.

[0022] In this embodiment, the transport vehicle 1 comprises a transport vehicle control unit 13 and a wireless communication device 14. The transport vehicle control unit 13 is configured using a processing unit such as a CPU (Central Processing Unit). The wireless communication device 14 is configured to communicate with the control device 2. In this example, the wireless communication device 14 is configured to communicate wirelessly with each of the multiple access point APs. Each of the multiple access point APs is configured to communicate with the control device 2 via a wired connection. That is, the wireless communication device 14 is configured to communicate with the control device 2 via any of the multiple access point APs.

[0023] As shown in Figure 3, the control device 2 is connected to an operating terminal. Operators can input various commands to the control device 2 by operating the operating terminal, and can also refer to the control status using the operating terminal.

[0024] The access point (AP) is configured using wireless access point equipment. The access point (AP) is configured to emit radio waves. The communication strength between the access point (AP) and the transport vehicle (1) is expressed as RSSI (Received Signal Strength Indicator). The unit is, for example, decibel-milliwatt (dBm).

[0025] As explained above, in the goods transport equipment 100 related to this disclosure, wireless communication via an access point AP is used for communication between the control device 2 and the transport vehicle 1. Therefore, communication failures may occur between the transport vehicle 1 and the access point AP. Such communication failures may be caused by abnormalities in the communication equipment or the surrounding environment, but it is difficult to quickly identify the cause. Furthermore, if either bidirectional communication between the control device 2 and the transport vehicle 1 is not satisfactory, it can be said that there is a communication failure. In other words, when a communication failure occurs, it may be that only the communication from the control device 2 to the transport vehicle 1 is faulty, only the communication from the transport vehicle 1 to the control device 2 is faulty, or both bidirectional communications are faulty. However, it is difficult to quickly identify the details of the communication failure.

[0026] As shown in Figure 3, in the goods transport equipment 100 according to this disclosure, if communication from the transport vehicle 1 to the control device 2 is interrupted, the control device 2 assumes that communication from the control device 2 to the transport vehicle 1 is valid and sends a command Co to the transport vehicle 1 to restore communication. To elaborate, if communication from the transport vehicle 1 to the control device 2 is interrupted, the control device 2 cannot confirm a response from the transport vehicle 1. Therefore, the control device 2 cannot confirm that communication from the control device 2 to the transport vehicle 1 is valid. However, in the goods transport equipment 100 according to this disclosure, the control device 2 assumes that communication from the control device 2 to the transport vehicle 1 is valid and sends a command Co to the transport vehicle 1. In other words, the control device 2 sends a command Co to the transport vehicle 1 regardless of whether communication from the control device 2 to the transport vehicle 1 is valid or invalid. As a result, if communication from the control device 2 to the transport vehicle 1 is valid, the command Co reaches the transport vehicle 1, and the transport vehicle 1 performs a task corresponding to the command Co, thereby restoring communication. Furthermore, the command Co for restoring communication from the control device 2 to the transport vehicle 1 only needs to be transmitted after communication from the transport vehicle 1 to the control device 2 has been lost. For example, the command Co may be transmitted simultaneously with the loss of communication from the transport vehicle 1 to the control device 2, immediately after the loss of communication, or after a predetermined period of time has elapsed since the loss of communication.

[0027] As shown in Figure 4, in this embodiment, the command Co transmitted by the control device 2 includes a point switching command that causes the transport vehicle 1 to switch to a connected access point AP. This prompts the transport vehicle 1 to switch to an access point AP with stronger communication strength. Consequently, it becomes easier to restore communication between the control device 2 and the transport vehicle 1.

[0028] In this embodiment, when the transport vehicle 1 receives a point switching command, if there are multiple access point APs that are candidates for a new connection destination, it selects one of these multiple access point APs and switches the connection destination to the selected access point AP. For example, the transport vehicle 1 may be equipped with a reception strength detection unit (not shown) that detects the reception strength of radio waves, and may select the access point AP to connect to based on the detection result by the reception strength detection unit. In this case, the transport vehicle 1 should select the access point AP with the strongest reception strength.

[0029] As shown in the example in Figure 4, when a transport vehicle 1, which is moving while connected to the first access point AP1, receives a point switching command from the control device 2, it switches its connection destination to an access point AP other than the first access point AP1 (in the illustrated example, the second access point AP2 or the third access point AP3). In the illustrated example, the transport vehicle 1 switches its connection destination from the first access point AP1 to the second access point AP2.

[0030] As shown in Figure 5, in this embodiment, the command Co transmitted by the control device 2 includes a movement command to move the transport vehicle 1 from its current location. This increases the likelihood that the transport vehicle 1 will move to a location with better communication conditions than its current location. Consequently, it becomes easier to restore communication between the control device 2 and the transport vehicle 1.

[0031] The premise for sending a movement command is that communication from the transport vehicle 1 to the control device 2 has been lost. Therefore, the control device 2 is unable to determine the current location of the transport vehicle 1. However, once the control device 2 sends a movement command to the transport vehicle 1, the transport vehicle 1 will move from its current location, regardless of its current position. Once the transport vehicle 1 has started moving from its current location, it will search for a connectable access point AP and attempt to connect to one of the found access points APs. If the connection is successful, communication between the control device 2 and the transport vehicle 1 will be restored. If the transport vehicle 1 is stopped at its current location and performing an item transfer operation, it will move from its current location after completing the item transfer operation.

[0032] In this embodiment, the movement command includes information about the destination to which the transport vehicle 1 should move. Alternatively, the control device 2 transmits a movement command to the transport vehicle 1 and also specifies the destination to which the transport vehicle 1 should move.

[0033] In this embodiment, multiple information holders M are installed at intervals along the direction of the path 8. In Figure 5, for the sake of explanation, one information holder M is shown. Each information holder M holds address information for the location where it is installed. The transport vehicle 1 is equipped with a reader that reads address information from the information holders M, and travels along the path 8 while reading the address information of each information holder. For example, a one-dimensional code or a two-dimensional code can be used as the information holder M, and a one-dimensional code reader or a two-dimensional code reader can be used as the reader.

[0034] In the example shown in Figure 5, the information holder M located at address 1001 is designated as the destination for the transport vehicle 1. Upon receiving a movement command, the transport vehicle 1 moves towards address 1001. Upon arriving at address 1001, the transport vehicle 1 attempts to connect with the nearest access point AP that it had reached earlier. If the connection is successful, communication between the control device 2 and the transport vehicle 1 is restored.

[0035] Furthermore, if the transfer target location 9 includes stations (locations where the transport vehicle 1 can be forced to move) and stations (locations where the transport vehicle 1 cannot be forced to move) then it is preferable that the stations where the transport vehicle 1 can be forced to move be designated as the destination for the transport vehicle 1 when a move command is issued. In addition, the transfer target location 9 may include stations (locations where the transport vehicle 1 can wait) and stations (locations where the transport vehicle 1 cannot wait). In this case, if multiple stations where the transport vehicle 1 cannot wait are sequentially set as destinations for the transport vehicle 1 when a move command is issued, the transport vehicle 1 can be kept in a constantly moving state, thereby increasing the number of access point APs that can be candidates for connection. Consequently, the number of connection attempts can be increased, and the restoration of communication between the control device 2 and the transport vehicle 1 can be expected. In this case, for example, it is preferable that multiple stations where the transport vehicle 1 cannot wait be set in a closed-loop route that the transport vehicle 1 can travel around without stopping.

[0036] As described above, in this embodiment, the control device 2 is configured to transmit a confirmation signal Sc to the transport vehicle 1, and the transport vehicle 1 is configured to transmit a receipt signal Sr to the control device 2 in response to receiving the confirmation signal Sc (see Figure 2).

[0037] As shown in Figure 6, in this embodiment, the control device 2 is configured to repeatedly transmit a confirmation signal Sc to the transport vehicle 1 at a set period C. The horizontal axis in Figure 6 represents time T. The control device 2 transmits the confirmation signal Sc to the transport vehicle 1 at the timing indicated by "ON" in the figure.

[0038] In this embodiment, if the control device 2 does not receive a signal Sr from the transport vehicle 1 for a predetermined set period P, it executes a period change process to shorten the set period C.

[0039] In this embodiment, multiple setting periods P are set, and the control device 2 executes a period change process each time a setting period P has elapsed. In the example shown in Figure 6, at least a first setting period P1, a second setting period P2, and a third setting period P3 are set.

[0040] The control device 2 transmits an acknowledgment signal Sc to the transport vehicle 1 at a first set cycle C1 from the time it last received the receipt signal Sr from the transport vehicle 1 (hereinafter referred to as "final receipt time T0") until the first set period P1 has elapsed. The first set period P1 is, for example, 30 seconds, and the first set cycle C1 is, for example, 10 seconds. In this case, the control device 2 will transmit the acknowledgment signal Sc three times within the first set period P1.

[0041] If the control device 2 does not receive a receipt signal Sr from the transport vehicle 1 between the final receipt time T0 and the elapsed time of the first setting period P1, it executes a period change process to change the set period C from the first set period C1 to the second set period C2. From the time T1 when the period change process to change the set period C to the second set period C2 is executed until the elapsed time of the second setting period P2, the control device 2 transmits a confirmation signal Sc to the transport vehicle 1 at the second set period C2. The second set period C2 is shorter than the first set period C1. Also, in this example, the second setting period P2 is shorter than the first set period P1. The second set period P2 is, for example, 15 seconds, and the second set period C2 is, for example, 5 seconds. In this case, the control device 2 will transmit the confirmation signal Sc three times within the second set period P2.

[0042] If the control device 2 does not receive a receipt signal Sr from the transport vehicle 1 between the time T1, when it executes the period change process to change the set period C to the second set period C2, and the second set period P2 has elapsed, it executes the period change process again to change the set period C from the second set period C2 to the third set period C3. From the time T2, when it executes the period change process to change the set period C to the third set period C3, until the third set period P3 has elapsed, the control device 2 sends a confirmation signal Sc to the transport vehicle 1 at the third set period C3. The third set period C3 is shorter than the second set period C2. Also, in this example, the third set period P3 is shorter than the second set period P2. The third set period P3 is, for example, 9 seconds, and the third set period C3 is, for example, 3 seconds. In this case, the control device 2 will send the confirmation signal Sc three times within the third set period P3.

[0043] In this embodiment, the control device 2 designates the transport vehicle 1 as a vehicle with communication problems if it does not receive a reception signal Sr from the transport vehicle 1 for a predetermined designation period Pt. The starting point of the designation period Pt is the last reception time T0. In the illustrated example, at time T3, the designation period Pt ends and the vehicle is designated as having communication problems. In this example, the designation period Pt is equal to the sum of the first setting period P1, the second setting period P2, and the third setting period P3. Individual information of the transport vehicle 1 designated as having communication problems is stored in the storage unit 21 of the control device 2. In this example, even after designating the transport vehicle 1 as having communication problems, the control device 2 continues to transmit a confirmation signal Sc to the transport vehicle 1 for a predetermined period. The control device 2 may also transmit an approach prohibition command to other transport vehicles 1 that do not have communication problems, prohibiting them from approaching the vehicle with communication problems. When a transport vehicle 1 receives a no-approach command, it will not approach the vehicle with communication problems by not entering the area surrounding the vehicle with communication problems (for example, the rear area). The no-approach command should preferably be issued after the time T3 when the vehicle with communication problems is identified. Alternatively, instead of issuing a no-approach command, the control device 2 may prohibit normal transport vehicles 1 other than the vehicle with communication problems from entering the lane in which the vehicle with communication problems was traveling. Or, when the control device 2 selects the travel path that minimizes the cost to the destination based on the cost (weight) of each lane, the control device 2 may increase the cost of the lane in which the vehicle with communication problems was traveling so that the lane is less likely to be selected as a travel path when determining the travel path for normal transport vehicles 1 other than the vehicle with communication problems.

[0044] As shown in Figure 7, in this embodiment, the control device 2 stores information about the transport vehicle 1 that has been identified as having a communication failure, and information about the location of the transport vehicle 1 at the time of identification, linking them together. As shown in Figure 7, "information about the transport vehicle 1 that has been identified as having a communication failure" is the individual information of the transport vehicle 1. "Information about the location of the transport vehicle 1 at the time of identification" is information about a location on the route 8.

[0045] In this embodiment, the control device 2 stores the individual information of the transport vehicle 1 that has been identified as having a communication failure, and the information of the location where the transport vehicle 1 is estimated to be located at the time of identification, linking them together. To elaborate, since the control device 2 cannot communicate with the transport vehicle 1 that has a communication failure, it cannot determine the current location of the transport vehicle 1. The location of the transport vehicle 1 at the final receipt time T0 is the last location of the transport vehicle 1 that the control device 2 can determine (hereinafter referred to as the "final known location"). In this embodiment, the control device 2 estimates the location of the transport vehicle 1 at the time it was identified as having a communication failure (hereinafter referred to as the "estimated location") based on the final known location of the transport vehicle 1. The control device 2 stores the individual information of the transport vehicle 1 that has been identified as having a communication failure, and the information of the estimated location of the transport vehicle 1 at the time of identification, in the storage unit 21 (see Figure 2). The storage unit 21 may be located outside the control device 2 (for example, on a server that can communicate with the control device 2).

[0046] As described above, the information stored in the memory unit 21 by the control device 2, namely the individual information of the transport vehicle 1 that has been identified as having a communication failure, and the information on the estimated position of the transport vehicle 1 at the time of identification, can be used to identify the cause of the communication failure that occurred between the control device 2 and the transport vehicle 1. For example, by using the information of the transport vehicle 1 that has been identified as having a communication failure, it becomes possible to determine whether the communication failure is due to a specific individual vehicle. Also, for example, by using the information on the estimated position of the transport vehicle 1 at the time of identification, it becomes possible to determine whether the communication failure is due to the surrounding environment (such as the presence of a structure that blocks radio waves) or a specific access point AP (such as a failure of the access point AP).

[0047] [Other Embodiments] Next, other embodiments will be described.

[0048] (1) In the above embodiment, an example was described in which the control device 2 stores information about the transport vehicle 1 that has been identified as having a communication failure and information about the position of the transport vehicle 1 at the time of identification in association. However, the control device 2 is not limited to this example, and may calculate the area from the position of the transport vehicle 1 at the final receipt time T0 (final identification position) to the position of the transport vehicle 1 that is estimated to be present at the time T3 when it has been identified as having a communication failure (estimated position), and store the information of this area in association with the information of the transport vehicle 1 that has been identified as having a communication failure.

[0049] (2) In the above embodiment, when the transport vehicle 1 receives a point switching command, if there are multiple access point APs that are candidates for a new connection destination, an example has been described in which the transport vehicle 1 selects one of these multiple access point APs and switches the connection destination to the selected access point AP. However, the configuration is not limited to this. The transport vehicle 1 may be configured to try to connect to each of the multiple access point APs without assigning any priority to them as connection destinations, when there are multiple access point APs that are candidates for a new connection destination. In this case, the transport vehicle 1 should maintain the connection state with the access point AP that was first connected to. This allows for the early restoration of communication between the control device 2 and the transport vehicle 1.

[0050] (3) In the above embodiment, an example was described in which multiple setting periods P, which serve as the basis for the control device 2 to execute the period change process, are set. However, the example is not limited to such an example, and a single setting period P may be set.

[0051] (4) In the above embodiment, an example was described in which the first setting period P1, the second setting period P2, and the third setting period P3 are set to become progressively shorter in the order described. However, the example is not limited to this example, and for example, the second setting period P2 and the third setting period P3 may be set to the same length.

[0052] (5) In the above embodiments, an example was described in which each of the multiple access point APs is configured to communicate with the control device 2 by wire. However, the invention is not limited to such an example, and at least some of the multiple access point APs may be configured to communicate with the control device 2 by wireless means.

[0053] (6) In the above embodiment, an example was described in which the route 8 is configured using rails 80 installed near the ceiling, and the transport vehicle 1 is configured as an overhead transport vehicle that travels while being supported by the rails 80. However, the transport vehicle 1 is not limited to this example and may be configured as a floor transport vehicle that travels on the floor. In this case, the route 8 may be configured using magnetic tape or the like provided along the floor, or it may be virtually set along the floor.

[0054] (7) The configurations disclosed in the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as they do not cause any inconsistencies. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of this disclosure.

[0055] [Summary of this embodiment] The following is a summary of this embodiment.

[0056] A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The control device and the transport vehicle are configured to communicate bidirectionally via one of the multiple access points. If communication from the transport vehicle to the control device is interrupted, the control device will assume that communication from the control device to the transport vehicle is still valid and will send a command to the transport vehicle to restore communication.

[0057] In a configuration where the control device and the transport vehicle communicate bidirectionally, even if communication from the transport vehicle to the control device is interrupted, communication from the control device to the transport vehicle is not necessarily impossible. According to this configuration, if communication from the transport vehicle to the control device is interrupted, the control device assumes that communication from the control device to the transport vehicle is still valid and sends a command to the transport vehicle to restore communication. If communication from the control device to the transport vehicle is still valid, the command will reach the transport vehicle, and the command will cause the transport vehicle to perform an action to restore communication. Therefore, this configuration makes it possible to maintain good communication between the control device and the transport vehicle.

[0058] Preferably, the command includes a point switching command that causes the transport vehicle to switch the access point to which it is connected.

[0059] This configuration allows the transport vehicle to switch the access point it is connected to. This encourages the transport vehicle to switch to an access point with stronger signal strength, making it easier to restore communication with the control device.

[0060] Preferably, the command includes a movement command to move the transport vehicle from its current position.

[0061] This configuration allows the transport vehicle to be moved from its current location. This increases the likelihood that the transport vehicle will move to a location with better communication conditions than its current location, making it easier to restore communication with the control device.

[0062] The control device is configured to repeatedly transmit a confirmation signal to the transport vehicle at a set interval. The transport vehicle is configured to transmit a receipt signal to the control device in response to receiving the confirmation signal. Preferably, if the control device does not receive the reception signal from the transport vehicle for a predetermined set period, it executes a period change process to shorten the set period.

[0063] With this configuration, the control device can periodically check the communication status with the transport vehicle. If there is no response (transmission of a received signal) from the transport vehicle for a set period, the frequency of sending a confirmation signal can be increased, thereby ensuring more opportunities for the transport vehicle to respond. In addition, by sending confirmation signals more frequently, the control device can more easily recognize that communication has been restored as soon as possible. As a result, the control device can send transport commands to the transport vehicle earlier, and as a result, the overall transport efficiency of the system is improved.

[0064] If the control device fails to receive the aforementioned signal from the transport vehicle for a predetermined period of time, it will designate the transport vehicle as a vehicle with a communication failure. The control device preferably stores information about the transport vehicle that has been identified as having a communication failure, and information about the transport vehicle's position at the time of identification, linked together.

[0065] This configuration makes it easier to identify the cause of communication failures between the control device and the transport vehicle. For example, by using information on a transport vehicle designated as having a communication failure, it becomes possible to determine whether the communication failure is due to a specific individual vehicle. Also, for example, by using information on the transport vehicle's location at the time of designation, it becomes possible to determine whether the communication failure is due to the surrounding environment or a specific access point. [Industrial applicability]

[0066] The technology relating to this disclosure can be used in an article transport system comprising a transport vehicle that moves along a predetermined route to transport articles, a control device that controls the transport vehicle, and a plurality of access points, each of which communicates wirelessly with the transport vehicle. [Explanation of symbols]

[0067] 100: Goods handling equipment 1: Transport vehicle 2: Control device 8: Route AP: Access Point P: Setting period C: Setting cycle Cо :Directive Pt: Certification reference period Sc: Confirmation signal Sr: Received signal

Claims

1. A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The control device and the transport vehicle are configured to communicate bidirectionally via one of the multiple access points. The control device, when communication from the transport vehicle to the control device is interrupted and information cannot be obtained from the transport vehicle, assumes that communication from the control device to the transport vehicle is valid and transmits a command to the transport vehicle to restore communication, thereby enabling the transport vehicle to transport.

2. A transport vehicle that moves along a predetermined route to carry goods, A control device for controlling the transport vehicle, An article transporting system comprising a plurality of access points, each of which communicates wirelessly with the transport vehicle, The control device and the transport vehicle are configured to communicate bidirectionally via one of the multiple access points. If communication from the transport vehicle to the control device is interrupted, the control device will assume that communication from the control device to the transport vehicle is still valid and will send a command to the transport vehicle to restore communication. The control device is configured to repeatedly transmit a confirmation signal to the transport vehicle at a set interval. The transport vehicle is configured to transmit a receipt signal to the control device in response to receiving the confirmation signal. The control device, if it does not receive the reception signal from the transport vehicle for a predetermined set period, executes a period change process to shorten the set period, thereby providing an item transporting system.

3. If the control device fails to receive the aforementioned signal from the transport vehicle for a predetermined period of time, it will designate the transport vehicle as a vehicle with a communication failure. The article transport equipment according to claim 2, wherein the control device stores information of the transport vehicle that has been identified as having a communication failure and information of the transport vehicle's position at the time of identification, linked together.

4. The article transport equipment according to any one of claims 1 to 3, wherein the command includes a point switching command that causes the transport vehicle to switch the access point to which it is connected.

5. The article transport equipment according to any one of claims 1 to 3, wherein the command includes a movement command to move the transport vehicle from its current position.

Images