Return vehicle system, and return vehicle control method

Abstract

[Task] To suppress the decrease in the operating rate of the device that performs processing on returned goods. [Solution] The transport vehicle system (1) comprises a plurality of transport vehicles (5) and a controller (10) that assigns transport commands to the plurality of transport vehicles (5). The controller (10) assigns a first transport command to an empty transport vehicle when a first transport command of a first priority occurs in a situation where the number of empty transport vehicles is a first number, and does not assign a second transport command to an empty transport vehicle when a second transport command of a second priority lower than the first priority occurs in a situation where the number of empty transport vehicles is a first number.

Description

Technology Field

[0001] The present invention relates to a transport vehicle system and a transport vehicle control method. Background Technology

[0002] Conventionally, in semiconductor device manufacturing plants and the like, a transport vehicle system is used to transport cargo (items) containing semiconductor wafers or reticles. In one embodiment of the transport vehicle system, the items are transported to a location where a device for processing the items is installed. Patent Document 1 discloses a technology that uses a transport order with assigned priority to preferentially assign a transport order with a high priority to the transport vehicle. Prior art literature

[0003] 1. Japanese Patent Publication No. 4705753 The problem to be solved

[0004] In conventional technology, it is difficult to assign a high-priority return order when a high-priority return order occurs after a low-priority return order has been assigned to a return vehicle and no empty vehicles remain. In other words, conventional technology assigns a return order at the time it occurs, as long as empty vehicles exist, regardless of the remaining number of empty vehicles; consequently, a situation may arise where a high-priority return order cannot be assigned. In a return vehicle system, if the situation where a high-priority return order cannot be assigned persists, the operating rate of the device processing the returned goods decreases.

[0005] The present invention provides a conveyor system capable of suppressing a decrease in the operating rate of a device that performs processing on a conveyed item, and a conveyor control method. means of solving the problem

[0006] A carrier system according to an embodiment of the present invention is a carrier system comprising a plurality of carriers and a controller that assigns a carrier command to the plurality of carriers, wherein the controller assigns a first carrier command to an empty carrier when a first carrier command of a first priority occurs in a situation where the number of empty carriers is a first number, and does not assign a second carrier command to an empty carrier when a second carrier command of a second priority lower than the first priority occurs in a situation where the number of empty carriers is a first number.

[0007] A carrier control method according to an embodiment of the present invention is a carrier control method for assigning a carrier command to a plurality of carriers, comprising: assigning a first carrier command to an empty carrier when a first carrier command of a first priority occurs in a situation where the number of empty carriers is a first number; and not assigning a second carrier command to an empty carrier when a second carrier command of a second priority lower than the first priority occurs in a situation where the number of empty carriers is a first number. Effects of the invention

[0008] According to the conveyor system and conveyor control method according to an embodiment of the present invention, when the number of empty conveyors is a first number, the assignment of a high-priority conveyor command is allowed and the assignment of a low-priority conveyor command is not allowed, thereby suppressing the occurrence of a situation where a high-priority conveyor command cannot be assigned, and thereby suppressing the decrease in the operating rate of the device performing processing on the conveyed goods.

[0009] In addition, in the conveyor system of the above embodiment, the controller may not assign the first conveyor command to the empty conveyor when a first conveyor command of the first priority occurs in a situation where the number of empty conveyors is less than the first number. According to this embodiment, if the number of empty conveyors is less than the first number, even if it is a conveyor command of high priority, it is not assigned, so it is possible to suppress a situation where there is a shortage of empty conveyors and no empty conveyors exist in a location where the assignment of conveyor commands can be carried out quickly. In addition, in the conveyor system of the above embodiment, the controller may assign the second conveyor command to the empty conveyor when a second conveyor command of the second priority occurs in a situation where the number of empty conveyors is greater than the first number. According to this embodiment, if the number of empty carriers is greater than the first number, the assignment of low-priority carrier orders is permitted, thereby preventing a situation where no empty carriers exist even when low-priority carrier orders are assigned. Furthermore, in the carrier system of the above embodiment, the second priority is divided into multiple indices for priority that decrease in order, and the first number is divided into multiple indices for the number of empty carriers that increase in order, and the controller may allow the assignment of lower-priority carrier orders to empty carriers as the number of empty carriers increases. According to this embodiment, after dividing the priority indices and the indices for the number of empty carriers into multiples, the assignment of lower-priority carrier orders to empty carriers as the number of empty carriers increases is permitted; thus, by flexibly changing the indices according to the scale of the system or user requirements, a situation where higher-priority carrier orders cannot be assigned is prevented. In addition, in the conveyor system of the above embodiment, when a highest priority conveyor command of a specific priority higher than the first priority occurs, the controller may be allowed to assign the highest priority conveyor command to an empty conveyor regardless of the number of empty conveyors.According to this embodiment, since a priority return order is assigned to an empty return vehicle regardless of the number of empty return vehicles, a return intended to be carried out immediately can be processed quickly. Furthermore, in the return vehicle system of the above embodiment, the controller is equipped with a plurality of area controllers, and each of the plurality of area controllers assigns a return order to a return vehicle within its jurisdictional area. When a first return order occurs in a situation where the sum of the number of empty return vehicles within the jurisdictional area and the number of empty return vehicles outside the jurisdictional area is the first number, the first return order is assigned to the empty return vehicle. However, when a second return order occurs in a situation where the sum of the number of empty return vehicles within the jurisdictional area and the number of empty return vehicles outside the jurisdictional area is the first number, the second return order does not need to be assigned to the empty return vehicle. According to this embodiment, since the sum of the number of empty return vehicles in a plurality of areas is used, the assignment of return orders can be realized targeting empty return vehicles existing in a plurality of areas. In addition, in the conveyor system of the above embodiment, the controller may increase the priority of a conveyor command that is not assigned to any conveyor as time elapses from the occurrence of the conveyor command. According to this embodiment, since the priority is increased over time even for conveyor commands with low priority, it is possible to prevent low-priority conveyor commands from remaining unassigned. In addition, in the conveyor system of the above embodiment, the controller may increase the priority in stages as time elapses. According to this embodiment, since the priority increase is carried out in stages, it is possible to prevent raising a low priority to a high priority in a short period of time. In addition, in the conveyor system of the above embodiment, the controller may allow the increase in priority up to an upper limit that is set larger the higher the priority at the time of occurrence of the conveyor command. According to this embodiment, it is possible to prevent excessively raising a low priority. Brief explanation of the drawing

[0010] FIG. 1 is a drawing showing an example of the arrangement of a transport vehicle system according to a first embodiment. FIG. 2 is a drawing showing an example of the configuration of a transport vehicle system according to a first embodiment. FIG. 3 is a block diagram showing an example of the configuration of a controller (area controller) according to a first embodiment. FIG. 4 is a diagram showing an example of information stored in a transport vehicle information table according to a first embodiment. FIG. 5 is a diagram showing an example of information stored in a return command information table according to a first embodiment. FIG. 6 is a flowchart showing an example of carrier control processing according to the first embodiment. FIG. 7 is a flowchart illustrating an example of return command assignment processing according to the first embodiment. FIG. 8 is a flowchart illustrating an example of return command assignment processing according to the first embodiment. FIG. 9 is a flowchart illustrating an example of return command assignment processing according to the first embodiment. FIG. 10 is a flowchart illustrating an example of return command assignment processing according to a first embodiment. FIG. 11 is a block diagram showing an example of the configuration of a controller (area controller) according to a second embodiment. FIG. 12 is a flowchart showing an example of priority increase processing according to a second embodiment. Specific details for implementing the invention

[0011] In the following, embodiments are described with reference to the drawings. The present invention is not limited to the forms described below. In the drawings, to explain the embodiments, the scale may be appropriately changed, such as by enlarging, reducing, or emphasizing parts of the figure.

[0012] [First embodiment] FIG. 1 is a drawing showing an example of the arrangement of a conveyor system according to a first embodiment. FIG. 2 is a drawing showing an example of the configuration of a conveyor system according to a first embodiment. The conveyor system (1) has a controller (3), a plurality of conveyors (5), and a controller (10). For example, the conveyor system (1) is a system that is deployed and installed in a semiconductor device manufacturing plant and conveys containers (articles), such as a FOUP (Front-Opening Unified Pod) containing a semiconductor wafer used in the manufacture of a semiconductor device, or a reticle pod containing a processing component such as a reticle.

[0013] Each of the multiple transport vehicles (5) travels along a track (7). The track (7) is the travel area of ​​the multiple transport vehicles (5). The multiple transport vehicles (5) are, for example, ceiling-mounted vehicles. The track (7) is a travel rail installed, for example, on the ceiling of a clean room. The track (7) is installed adjacent to a processing device (not shown) or a stocker (not shown), etc. The processing device is, for example, an exposure device, a coater developer, a film manufacturing device, or an etching device, and performs various processes on semiconductor wafers in containers transported by the multiple transport vehicles (5). The stocker (automatic warehouse) stores, for example, containers transported by the multiple transport vehicles (5). Additionally, the multiple transport vehicles (5) may be ground-mounted trolleys. If the transport vehicles (5) are ground-mounted trolleys, the track (7) is installed on the floor, etc. Also, the city's track (7) is an example and can be set arbitrarily.

[0014] A power supply line (not shown) is installed on the track (7). The power supply line is arranged along the track (7). For example, alternating current is supplied to the power supply line. Each of the plurality of carrier cars (5) is equipped with a receiving coil and receives power from the power supply line non-contactually by electromagnetic induction. Since power is supplied non-contactually, the generation of dust and other particles caused by contact can be suppressed, making it suitable for a clean room.

[0015] The track (7) is divided into multiple areas (9). A controller (10) for controlling a transport vehicle (5) is placed in each of the multiple areas (9). The controller (10) may be referred to as an "area controller." The controller (10) controls the transport vehicle (5) traveling within the area it is placed in as its jurisdictional area. The transport vehicle (5) and the controller (10) are connected to communicate wirelessly. Additionally, each of the multiple controllers (10) is connected to communicate wirelessly or via wired connection with a controller (10) outside the jurisdictional area, extending beyond the area (9).

[0016] The controller (3) outputs a return command containing information indicating the cargo pickup location or cargo unloading location of the goods. The controller (3) may be referred to as the "upper controller." Each of the controller (3) and the controller (10) is connected to communicate wirelessly or via a wired connection. The upper controller, the controller (3), transmits a return command to the lower controller, the controller (10). The controller (10) executes the assignment processing of the received return command and determines the return vehicle (5) to return the goods. Based on these, the return vehicle (5) drives toward the cargo pickup location or cargo unloading location of the goods based on the return command.

[0017] FIG. 3 is a block diagram showing an example of the configuration of a controller (area controller) according to a first embodiment. Each controller (10) has the same configuration. As shown in FIG. 3, the controller (10) has a communication unit (101), a memory unit (110), and a control unit (120). The controller (10) is a computer device that performs various processes, such as a CPU (Central Processing Unit), main memory, memory device, communication device, etc. Furthermore, the configuration of the computer device is arbitrary; for example, it may be configured by a single device or by multiple devices.

[0018] The communication unit (101) is connected to communicate with other controllers (10) or carrier vehicles (5) located in the area (9) under its jurisdiction, and transmits and receives various information. Additionally, the controller (10) performs periodic communication with all carrier vehicles (5) located in the area (9) under its jurisdiction through polling, etc.

[0019] The memory unit (110) has a carrier information table (111) and a carrier command information table (112). The memory unit (110) is, for example, a non-volatile memory and stores various information received by the communication unit (101). The carrier information table (111) stores information regarding a plurality of carriers (5). Specifically, the carrier information table (111) stores information regarding carriers (5) in an area (9) within the jurisdiction of the controller (10) and information regarding carriers (5) in an area (9) outside the jurisdiction of the controller (10).

[0020] FIG. 4 is a diagram showing an example of information stored in a transport vehicle information table according to a first embodiment. As shown in FIG. 4, the transport vehicle information table (111) stores information corresponding to "transport vehicle ID," "status," and "current location" for each transport vehicle (5) existing in an area (9) (within the jurisdiction area) and an area (9) (outside the jurisdiction area). The transport vehicle ID is identification information that uniquely identifies each of the multiple transport vehicles (5). The status is information indicating whether the transport vehicle (5) is an empty transport vehicle. In addition, the status may include information indicating the status of the transport vehicle (5), such as whether the status of the transport vehicle (5) is normal (usable). For example, 1 (in use) is a flag indicating that it is traveling on the track (7) based on a transport command and indicates that it is not an empty transport vehicle. Additionally, 0 (unused) is a flag indicating that driving based on a return command is not taking place, and indicates that it is an empty return vehicle. The current location is information indicating the current location in the driving area of ​​the return vehicle (5). By referring to the return vehicle information table (111), the controller (10) can recognize the number of empty return vehicles in the area (9) within the jurisdiction, the number of empty return vehicles in the area (9) outside the jurisdiction, and the number of empty return vehicles in a plurality of areas (9).

[0021] The return command information table (112) stores information regarding return commands. FIG. 5 is a diagram showing an example of information stored in the return command information table according to the first embodiment. As shown in FIG. 5, the return command information table (112) stores information corresponding to "return command ID," "command content," "priority," and "occurrence time." The return command ID is identification information that uniquely identifies each return command. The command content includes information regarding the cargo pickup location (from) or cargo unloading location (to). Priority is information indicating the degree of priority of the return command. It is desirable for return commands to be executed preferentially as the priority is higher. As an example, the priority is represented as a larger number as the priority is higher. In this embodiment, a priority of less than 40 is set to “low,” a priority of 40 or more but less than 60 is set to “medium,” a priority of 60 or more is set to “high,” and a priority of 99 is set to “specific” (specific priority).

[0022] For example, a return command with a priority of "low" corresponds to a return command from a stoker to a stoker. For example, a return command with a priority of "medium" corresponds to a return command from a stoker to a processing unit. For example, a return command with a priority of "high" corresponds to a return command from a processing unit to a stoker. That is, in this embodiment, one of the objectives is to suppress the decrease in the operation of the processing unit by prioritizing return to the processing unit or return from the processing unit. In addition, a return command with a priority of "specific" (specific priority) can be assigned not only to empty return vehicles but also to return vehicles (5) that are executing other return commands. Furthermore, the distinction of priority is not limited to this and can be set to any range, any numerical value, or any number of distinctions. The occurrence time is information indicating the time when the return command occurred. The time at which the return command occurs can be unified into either the time at which the controller (3) transmits or the time at which the controller (10) receives.

[0023] The control unit (120) has a data processing unit (121), a carrier information output unit (122), a number calculation unit (123), an allocation unit (124), a path search unit (125), and a carrier determination unit (126). The data processing unit (121) performs processing of various information received by the communication unit (101) and processing of various information transmitted by the communication unit (101). Specifically, the data processing unit (121) stores various information received by the communication unit (101) (e.g., carrier information, carrier command information, etc.) in the memory unit (110). Additionally, when carrier command information is received by the communication unit (101), the data processing unit (121) may notify the number calculation unit (123) of the fact that it has been received. Additionally, the data processing unit (121) receives various information (e.g., carrier information, carrier command, etc.) from the carrier information output unit (122) or the carrier determination unit (126) and controls the transmission of various information by the communication unit (101).

[0024] The carrier information output unit (122) outputs carrier information existing in the area (9) under the jurisdiction of the controller (10) (itself). The carrier information output unit (122) periodically outputs carrier information. Specifically, the carrier information output unit (122) obtains carrier information of the area (9) under its jurisdiction from the carrier information table (111) (see (A) in FIG. 4) and outputs it to the data processing unit (121). When the data processing unit (121) receives carrier information from the carrier information output unit (122), it executes control to transmit the corresponding carrier information to another controller (10) located in an area (9) outside its jurisdiction via the communication unit (101). When another controller (10) receives carrier information, it stores the received carrier information in the carrier information table (111) (see (B) in FIG. 4) as carrier information for an area (9) outside its jurisdiction. That is, when the data processing unit (121) receives carrier information through the communication unit (101), it stores it in the carrier information table (111) as carrier information for an area (9) outside its jurisdiction. In addition, the data processing unit (121) periodically receives carrier information from a carrier (5) existing in an area (9) within its jurisdiction through the communication unit (101) and stores it in the carrier information table (111) (see (A) in FIG. 4).

[0025] The number of vehicles calculation unit (123) calculates the number of empty transport vehicles. Specifically, the number of vehicles calculation unit (123) calculates the number of data with a status of “0 (unused)” (equivalent to empty transport vehicles) by referring to the transport vehicle information table (111). Here, the number of vehicles calculation unit (123) sets the sum of the number of data in the area (9) within the jurisdiction and the number of data in the area (9) outside the jurisdiction as the number of empty transport vehicles. That is, the number of empty transport vehicles is the sum of the number of empty transport vehicles existing in each of the multiple areas (9). In addition, the number of vehicles calculation unit (123) may calculate the number of empty transport vehicles periodically, or may calculate it at the timing when the data processing unit (121) receives a transport order.

[0026] The allocation unit (124) determines the allocation of return orders using the return order information table (112). Specifically, the allocation unit (124) decides to allocate the first return order to the empty return vehicle when the number of empty return vehicles calculated by the number calculation unit (123) is the first number, by referring to the return order information table (112) and the first return order of the first priority occurs. Additionally, the allocation unit (124) decides not to allocate the second return order to the empty return vehicle when the number of empty return vehicles calculated by the number calculation unit (123) is the first number, by referring to the return order information table (112) and the second return order of the second priority, which is lower than the first priority, occurs. Here, the first number is not an indicator representing a predetermined number, but an indicator having a range such as X or greater and less than Y. That is, the allocation unit (124) decides to allocate only the first return order to the empty return vehicle when the number of empty return vehicles is the first number (X or greater, less than Y) and when the first return order of the first priority and the second return order of the second priority, which is lower than the first priority, occur. In addition, the allocation unit (124) determines that if return orders with the same priority occur, the return order with the higher priority value is the target for allocation, and if the priority values ​​are the same, the return order that is earlier is the target for allocation based on the time of occurrence.

[0027] Additionally, the allocation unit (124) decides not to allocate the first return order to the empty return vehicle when the number of empty return vehicles calculated by the number calculation unit (123) is less than the first number, by referring to the return order information table (112) and the first return order of the first priority occurs. That is, the allocation unit (124) decides not to allocate the first return order even if it is the first return order of the first priority when the number of empty return vehicles is less than the first number (less than X).

[0028] Additionally, the allocation unit (124) decides to allocate a second return order to an empty return vehicle when a second return order of the second priority occurs by referring to the return order information table (112) in a situation where the number of empty return vehicles calculated by the number calculation unit (123) is a second number greater than the first number. That is, the allocation unit (124) decides to allocate a second return order even if it is a second return order of the second priority when the number of empty return vehicles is a second number (Y or more).

[0029] In this embodiment, the first number is divided into multiple values ​​as an indicator of the number of empty transport vehicles that increase in succession. Additionally, the second priority is divided into multiple values ​​as an indicator of priority that decreases in succession. That is, the allocation unit (124) allows the allocation of transport commands of lower priority to empty transport vehicles as the number of empty transport vehicles increases.

[0030] Additionally, the allocation unit (124) allows the allocation of a priority return order to an empty return vehicle regardless of the number of empty return vehicles when a priority return order of a specific priority higher than the first priority occurs by referring to the return order information table (112). That is, when a priority return order of a specific priority occurs, the allocation unit (124) allows the allocation of a priority return order to an empty return vehicle regardless of whether the number of empty return vehicles is less than the first number (less than X), the first number (X or more and less than Y), or the second number (Y or more). As described above, a priority return order of a specific priority can be allocated not only to empty return vehicles but also to other return vehicles (5) that are executing other return orders. Additionally, the allocation unit (124) may refer to the return order information table (112) to check for the existence of a top-priority return order of a specific priority prior to the calculation of the number of empty return vehicles by the number calculation unit (123), and decide to allocate a top-priority return order if a top-priority return order of a specific priority exists. Alternatively, the allocation unit (124) may receive from the data processing unit (121) that a top-priority return order of a specific priority has been received and decide to allocate a top-priority return order. That is, when a top-priority return order of a specific priority occurs, the allocation of the top-priority return order may be determined even if the calculation of the number of empty return vehicles by the number calculation unit (123) is not executed. In addition, as mentioned above, in situations where the number of empty return vehicles is less than the first number, even if it is the first return order of the first priority, it is not assigned. One of the reasons for this is to ensure that when a top priority return order of a specific priority of higher priority occurs, it is assigned quickly.

[0031] The path search unit (125) sets a driving path according to a return command. Specifically, the path search unit (125) sets a driving path of the return vehicle (5) based on a return command determined to be assigned by the assignment unit (124), and map information of the return vehicle system (1). Additionally, the path search may be omitted if the system searches for a path on the return vehicle (5) side.

[0032] The carrier determination unit (126) determines the carrier (5) to execute the carrier command. Specifically, the carrier determination unit (126) determines the carrier (5) to execute the carrier command determined by the allocation unit (124) by referring to the carrier information table (111). For example, the carrier determination unit (126) determines the carrier (5) (empty carrier) whose status stored in the carrier information table (111) is “0 (unused)” as the carrier (5) to execute the carrier command. Here, if there is no empty carrier in the area (9) under jurisdiction, the carrier determination unit (126) determines the empty carrier existing in the area (9) outside the jurisdiction as the carrier (5) to execute the carrier command. Additionally, the carrier determination unit (126) preferably adopts an empty carrier located in an area outside the jurisdiction (9) that is closer to the jurisdiction area (9) based on the current location. By determining the closer empty carrier as the carrier (5) to execute the carrier order, the carrier efficiency can be improved. Additionally, when the carrier order determined by the allocation unit (124) is a top priority carrier order of a specific priority, the carrier determination unit (126) may determine the carrier (5) to execute the carrier order by targeting an empty carrier, or may determine the carrier (5) to execute the carrier order by targeting a carrier (5) that is executing another carrier order. Additionally, when there is no empty carrier, it is preferable for the carrier determination unit (126) to determine the carrier (5) to execute the carrier order by targeting a carrier (5) that is executing another carrier order. Then, the return vehicle determination unit (126) instructs the data processing unit (121) to transmit a return command and a driving path set by the path search unit (125) to the return vehicle (5) that will execute the return command. Accordingly, the data processing unit (121) performs control to transmit the return command, etc. to the return vehicle (5) through the communication unit (101).

[0033] After transmitting a return command or the like to the return vehicle (5), the controller (10) updates the information stored in the return command information table (112). Specifically, the controller (10) deletes the information corresponding to the return command transmitted to the return vehicle (5) from the return command information table (112). Alternatively, the controller (10) may set a flag (a flag indicating that the return command has been completed) in the return command information table (112) for the information corresponding to the return command transmitted to the return vehicle (5). The controller (10) may delete the information for which the flag indicating that the return command has been completed has been set from the return command information table (112) at any timing. Additionally, since the controller (10) receives carrier information from the carrier (5) or another controller (10), at the timing after transmitting a carrier command, etc. to the carrier (5), the information stored in the carrier information table (111) does not need to be updated.

[0034] FIG. 6 is a flowchart illustrating an example of a carrier control process according to a first embodiment. As shown in FIG. 6, the number of carriers calculation unit (123) calculates the number of empty carriers (step S101). Specifically, the number of carriers calculation unit (123) calculates the number of data with a status of “0 (unused)” by referring to the carrier information table (111). The number of carriers calculation unit (123) sets the sum of the number of data in the area (9) within the jurisdiction and the number of data in the area (9) outside the jurisdiction as the number of empty carriers.

[0035] The allocation unit (124) determines the allocation of return commands based on the number of empty return vehicles and the priority of the return commands (step S102). Specifically, the allocation unit (124) allows the allocation of return commands of lower priority to empty return vehicles as the number of empty return vehicles increases, based on the number of empty return vehicles calculated by the number calculation unit (123) and the priority of return commands stored in the return command information table (112). Additionally, the details of the processing in step S102 will be described later.

[0036] The path search unit (125) searches for a driving path (step S103). Specifically, the path search unit (125) sets the driving path of the transport vehicle (5) based on the transport command determined to be assigned by the assignment unit (124) and map information of the transport vehicle system (1). The transport vehicle determination unit (126) determines the transport vehicle to which the transport command will be assigned (step S104). Specifically, the transport vehicle determination unit (126) determines the transport vehicle (5) to execute the transport command determined to be assigned by the assignment unit (124) by referring to the transport vehicle information table (111). The data processing unit (121) transmits the transport command (step S105). Specifically, the data processing unit (121) performs control to transmit the transport command, etc. to the transport vehicle (5) determined by the transport vehicle determination unit (126) through the communication unit (101).

[0037] FIGS. 7 to 10 are flowcharts illustrating examples of return command assignment processing according to the first embodiment. FIGS. 7 to 10 also show details of the processing in step S102. Furthermore, in the description of FIGS. 7 to 10, examples are given in which the index of the number of empty return vehicles is divided into less than the first number (less than X), the first number (X or more and less than Y), the second number (Y or more and less than Z), and the second number or more (Z or more), and the index of priority is divided into specific priority, first priority, second priority, and third priority (specific priority > first priority > second priority > third priority). Additionally, X, Y, and Z are natural numbers satisfying X < Y < Z.

[0038] As shown in FIG. 7, the allocation unit (124) determines whether there is a top priority return command of a specific priority (step S201). Specifically, the allocation unit (124) determines whether there is a top priority return command of a specific priority “99 (specific)” by referring to the return command information table (112). Then, if there is a top priority return command of a specific priority (step S201: YES), the allocation unit (124) determines the allocation of the top priority return command (step S202). Specifically, if there is a top priority return command of a specific priority “99 (specific)” in the return command information table (112), the allocation unit (124) determines the allocation of the corresponding top priority return command to the return vehicle (5). On the other hand, if there is no top priority return command of a specific priority (step S201: NO), the process proceeds to the flow in “A”.

[0039] As shown in FIG. 8, the allocation unit (124) determines whether the number of empty return vehicles is less than the first number (step S203). Specifically, the allocation unit (124) determines whether the number of empty return vehicles calculated by the number calculation unit (123) is less than the first number (less than X). At this time, if the number of empty return vehicles is less than the first number (step S203: YES), the allocation unit (124) terminates the processing without determining the allocation of return orders. Specifically, the allocation unit (124) does not perform the allocation of the first return order of the first priority, the second return order of the second priority, and the third return order of the third priority because the number of empty return vehicles is less than the first number (less than X) and the number of empty return vehicles is very small (or, there are no empty return vehicles).

[0040] Meanwhile, the allocation unit (124) determines whether the number of empty return vehicles is the first number when the number of empty return vehicles is not less than the first number (step S203: NO). Specifically, the allocation unit (124) determines whether the number of empty return vehicles is the first number (X or greater, less than Y) when the number of empty return vehicles calculated by the number calculation unit (123) is not less than the first number (less than X). At this time, the allocation unit (124) determines whether there is a first return command of the first priority when the number of empty return vehicles is the first number (step S204: YES) (step S205). Specifically, the allocation unit (124), when the number of empty return vehicles calculated by the number calculation unit (123) is the first number (X or greater, less than Y), refers to the return order information table (112) to determine whether there is a first return order with a first priority of "high". Meanwhile, when the number of empty return vehicles is not the first number (step S204: NO), the allocation unit (124) proceeds to the flow in "B".

[0041] The allocation unit (124) determines the allocation of the first return command when there is a first return command of the first priority (step S205: YES) (step S206). Specifically, the allocation unit (124) determines to allocate the first return command to an empty return vehicle when the first return command of the first priority "high" is stored in the return command information table (112). Here, the allocation unit (124) determines to allocate the first return command with a higher priority value to an empty return vehicle when multiple first return commands of the first priority "high" are stored in the return command information table (112), and when the priority values ​​are the same, determines to allocate the first return command with a earlier occurrence time to an empty return vehicle. Meanwhile, the allocation unit (124) terminates processing without determining the allocation of a return command when there is no first return command of the first priority (step S205: NO). Specifically, the allocation unit (124) terminates processing without determining the allocation of a return command because there is no assignable return command (first return command) in the first number (X or greater, less than Y).

[0042] As shown in FIG. 9, the allocation unit (124) determines whether the number of empty carriers is the second number (step S207). Specifically, the allocation unit (124) determines whether the number of empty carriers calculated by the number calculation unit (123) is the second number (Y or more, less than Z). At this time, if the number of empty carriers is not the second number (step S207: NO), the allocation unit (124) proceeds to the flow in "C". Specifically, since the number of empty carriers calculated by the number calculation unit (123) is the second number or more (Z or more), the allocation unit (124) proceeds to the flow in "C".

[0043] Meanwhile, the allocation unit (124) determines whether there is a first return command of the first priority when the number of empty return vehicles is the second number (step S207: YES) (step S208). Specifically, the allocation unit (124) determines whether there is a first return command of the first priority "high" by referring to the return command information table (112) when the number of empty return vehicles calculated by the number calculation unit (123) is the second number (Y or greater, less than Z). At this time, the allocation unit (124) determines the allocation of the first return command when there is a first return command of the first priority (step S208: YES) (step S209). Specifically, the allocation unit (124) decides to allocate the first return command to the empty return vehicle when the first return command of the first priority "high" is stored in the return command information table (112). Here, the allocation unit (124) decides to allocate the first return command with a higher priority value to an empty return vehicle when multiple first return commands with a first priority value of "high" are stored in the return command information table (112), and when the priority values ​​are the same, decides to allocate the first return command with a later occurrence time to an empty return vehicle.

[0044] The allocation unit (124) determines whether there is a second return command of a second priority when there is no first return command of a first priority (step S208: NO). Specifically, the allocation unit (124) determines whether there is a second return command of a second priority of "medium" when there is no first return command of a first priority of "high" stored in the return command information table (112). At this time, the allocation unit (124) determines whether there is a second return command of a second priority of "medium" when there is a second return command of a second priority (step S210: YES) (step S211). Specifically, the allocation unit (124) determines to allocate the second return command when there is a second return command of a second priority of "medium" stored in the return command information table (112). Here, the allocation unit (124) decides to allocate the second return command with a higher priority value to an empty return vehicle when the second return command with a second priority value of "medium" is stored in the return command information table (112), and when the priority values ​​are the same, decides to allocate the second return command with a later occurrence time to an empty return vehicle.

[0045] Meanwhile, the allocation unit (124) terminates processing without determining the allocation of a return command when there is no second return command of the second priority (step S210: NO). Specifically, the allocation unit (124) terminates processing without determining the allocation of a return command because there are no assignable return commands (first return command and second return command) in the second logarithm (Y or greater and less than Z).

[0046] FIG. 10 is a flow for the case where the number of empty return vehicles is greater than or equal to the second number (Z or greater), as described above. As shown in FIG. 10, the allocation unit (124) determines whether there is a first return order of a first priority (step S212). Specifically, the allocation unit (124) determines whether there is a first return order of a first priority "high" when the number of empty return vehicles calculated by the number calculation unit (123) is greater than or equal to the second number (Z or greater). At this time, if there is a first return order of a first priority (step S212: YES), the allocation unit (124) determines the allocation of the first return order (step S213). Specifically, the allocation unit (124) decides to allocate the first return command to an empty return vehicle when the first return command with a first priority of "high" is stored in the return command information table (112). Here, the allocation unit (124) decides to allocate the first return command with a higher priority value to an empty return vehicle when multiple first return commands with a first priority of "high" are stored in the return command information table (112), and when the priority values ​​are the same, it decides to allocate the first return command with a later occurrence time to an empty return vehicle.

[0047] Meanwhile, the allocation unit (124) determines whether there is a second return command of a second priority when there is no first return command of a first priority (step S212: NO). Specifically, the allocation unit (124) determines whether there is a second return command of a second priority of "medium" when there is no first return command of a first priority of "high" stored in the return command information table (112). At this time, the allocation unit (124) determines whether there is a second return command of a second priority of "medium" when there is a second return command of a second priority (step S214: YES) when there is a second return command of a second priority (step S215). Specifically, the allocation unit (124) determines to allocate the second return command to an empty return vehicle when there is a second return command of a second priority of "medium" stored in the return command information table (112). Here, the allocation unit (124) decides to allocate the second return command with a higher priority value to an empty return vehicle when the second return command with a second priority value of "medium" is stored in the return command information table (112), and when the priority values ​​are the same, decides to allocate the second return command with a later occurrence time to an empty return vehicle.

[0048] Meanwhile, the allocation unit (124) determines whether there is a third return command of a third priority when there is no second return command of a second priority (step S214: NO). Specifically, the allocation unit (124) determines whether there is a third return command of a third priority of "low" when there is no second return command of a second priority stored in the return command information table (112). At this time, the allocation unit (124) determines whether there is a third return command of a third priority of "low" when there is a third return command of a third priority (step S216: YES) (step S217). Specifically, the allocation unit (124) determines to allocate the third return command when there is a third return command of a third priority of "low" when there is a third return command stored in the return command information table (112). Here, the allocation unit (124) decides to allocate the third return command with a higher priority value to an empty return vehicle when the third return command with a third priority value of "low" is stored in the return command information table (112), and when the priority values ​​are the same, decides to allocate the third return command with a later occurrence time to an empty return vehicle.

[0049] As described above, the conveyor system (1) allows for the assignment of conveyor orders of lower priority to empty conveyors as the number of empty conveyors increases, based on an indicator of the number of empty conveyors that increases in order and an indicator of priority that decreases in order. This allows for flexible changes to the indicators according to the scale of the system or user requirements, thereby suppressing situations where high-priority conveyor orders cannot be assigned, and thus suppressing the decrease in the operating rate of the device (processing device) that performs processing on the conveyed goods. Furthermore, the conveyor system (1) allows for the assignment of a top-priority conveyor order to empty conveyors regardless of the number of empty conveyors when a top-priority conveyor order of a specific priority occurs, thereby enabling the rapid processing of conveyors intended to be performed immediately. Additionally, the conveyor system (1) uses the sum of the number of empty conveyors in multiple areas (9), so it can realize the assignment of conveyor orders to empty conveyors existing in multiple areas (9).

[0050] [Second embodiment] In the second embodiment, the same reference numerals are used for components identical to those in the above-described embodiment, and detailed descriptions may be omitted or simplified. In the second embodiment, the configuration of the transport vehicle system (1), etc., is identical to that of the above-described embodiment. FIG. 11 is a block diagram showing an example of the configuration of a controller (area controller) according to the second embodiment. As shown in FIG. 11, the controller (10a) has a communication unit (101), a memory unit (110), and a control unit (120a).

[0051] The memory unit (110) has a return vehicle information table (111) and a return command information table (112). Each piece of information stored in the memory unit (110) is the same as that in the above-described embodiment. In the second embodiment, the return command information table (112) is updated with priority information as described below.

[0052] The control unit (120a) has a data processing unit (121), a carrier information output unit (122), a logarithm calculation unit (123), an allocation unit (124), a path search unit (125), a carrier determination unit (126), and a priority update unit (127a). The priority update unit (127a) increases the priority of a carrier command that is not assigned to any carrier (5) according to the elapsed time from the occurrence of the carrier command. The carrier command information table (112) (see FIG. 5) stores information regarding carrier commands that are not assigned to any carrier (5). Accordingly, the priority update unit (127a) accesses the carrier command information table (112) and increases the priority of a carrier command for which a predetermined time has elapsed based on the date and time of occurrence of the carrier command. For example, the priority update unit (127a) increases the priority by "+5" if a predetermined time has elapsed since the occurrence of a return command with a priority of "30". In addition, the predetermined time can be set by, for example, the size of the return vehicle system (1) or the capacity (processing time, etc.) according to the processing device, and can be changed arbitrarily. In addition, the point at which the priority is increased can be changed arbitrarily.

[0053] Additionally, the priority update unit (127a) increases the priority stepwise as time progresses. The number of times the priority is increased is not specifically limited. Therefore, even if the initial priority is "low," it may be increased stepwise as time progresses to become "medium" or "high." Additionally, the priority update unit (127a) allows the priority to increase up to an upper limit that is set larger the higher the priority at the time of the return command occurrence. For example, the upper limit for an increase of "low" priority (e.g., less than 40) is set to "70," the upper limit for an increase of "medium" priority (e.g., 40 or more and less than 60) is set to "80," and the upper limit for an increase of "high" priority (e.g., 60 or more) is set to "90." Additionally, the upper limit can be changed at will.

[0054] By these, each part of the control unit (120a) performs various processing described in the above embodiment using a return command information table (112) whose priority is updated by the priority update unit (127a).

[0055] FIG. 12 is a flowchart illustrating an example of priority increase processing according to a second embodiment. As shown in FIG. 12, the priority update unit (127a) determines whether there is an unassigned return command (step S301). Specifically, the priority update unit (127a) accesses the return command information table (112) and determines whether information regarding the return command is stored. At this time, the priority update unit (127a) terminates the processing if there is no unassigned return command (step S301: NO). Specifically, the priority update unit (127a) terminates the processing if information regarding the return command is not stored in the return command information table (112).

[0056] Meanwhile, the priority update unit (127a) determines whether the priority of a return command has reached an upper limit when there is an unassigned return command (step S301: YES). Specifically, the priority update unit (127a) determines whether the priority of a return command has reached an upper limit based on the priority when stored in the return command information table (112) when information regarding a return command is stored in the return command information table (112).

[0057] At this time, the priority update unit (127a) terminates processing when the priority of the return command reaches an upper limit (step S302: YES). Specifically, the priority update unit (127a) terminates processing when it reaches an upper limit based on the priority when stored in the return command information table (112). Meanwhile, if the priority of the return command does not reach an upper limit (step S302: NO), the priority update unit (127a) increases the priority based on the elapsed time since the occurrence of the return command (step S303). Specifically, if the priority update unit (127a) does not reach an upper limit based on the priority when stored in the return command information table (112), it increases the priority of the return command for which a predetermined time has elapsed based on the date and time of the return command occurrence.

[0058] As described above, the return vehicle system (1) increases the priority of return orders that are not assigned to any return vehicle (5) over time from the occurrence of the return order, thereby preventing return orders of low priority from remaining unassigned. Additionally, the return vehicle system (1) increases the priority stepwise up to an upper limit that is set larger the higher the priority at the time of occurrence of the return order, thereby preventing the excessive increase of the original low priority.

[0059] In the above-described embodiment, the controller (10) includes, for example, a computer system. The controller (10) reads a carrier control program stored in a memory unit (110) and performs various processes according to the read carrier control program. The carrier control program causes, for example, a computer to perform the following: assigning a first carrier command to an empty carrier when a first carrier command of a first priority occurs in a situation where the number of empty carriers is a first number, and not assigning a second carrier command to an empty carrier when a second carrier command of a second priority lower than the first priority occurs in a situation where the number of empty carriers is a first number. The carrier control program may be stored and provided on a computer-readable storage medium.

[0060] Although embodiments have been described above, the technical scope of the present invention is not limited to the embodiments described above. It is obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. Furthermore, forms with modifications or improvements are also included within the technical scope of the present invention. One or more of the requirements described in the embodiments described above may be omitted. Additionally, the requirements described in the embodiments described above may be appropriately combined. Furthermore, the execution order of each process shown in the embodiments described above can be realized in any order, provided that the output of the preceding process is not used in the subsequent process. Furthermore, regarding the operations in the embodiments described above, even if terms such as "first," "next," or "following" are used for convenience, it is not mandatory to carry them out in this order. Additionally, to the extent permitted by law, the disclosure of all literature cited in the embodiments described above is incorporated as part of the description in the text.

[0061] Furthermore, the technical scope of the present invention is not limited to the embodiments described above. One or more of the requirements described in the embodiments described above may be omitted. Additionally, the requirements described in the embodiments described above may be appropriately combined. Furthermore, to the extent permitted by law, the disclosure of Japanese Patent Application No. 2020-147385 and all documents cited in the embodiments described above shall be incorporated into the description of the text. Explanation of the symbols

[0062] 1. Return Vehicle System 3 Controller (Parent) 5 return vehicle 7 orbits Area 9 10 Controller (Area) 101 Communications Department 110 Memory Section 111 Return Vehicle Information Table 112 Return Order Information Table 120 control unit 121 Data Processing Unit 122 Return Vehicle Information Output Section 123 Logarithmic Calculation Section 124 allocation section 125 Pathfinding Section 126 Return Vehicle Decision Unit

Claims

Claim 1 A transport vehicle system comprising a plurality of transport vehicles and a controller that assigns transport orders to the plurality of transport vehicles, wherein the controller assigns the first transport order to an empty transport vehicle when a first transport order of a first priority occurs in a situation where the number of empty transport vehicles is the first number, and does not assign the second transport order to an empty transport vehicle when a second transport order of a second priority lower than the first priority occurs in a situation where the number of empty transport vehicles is the first number, wherein the controller comprises a plurality of area controllers, and each of the plurality of area controllers assigns a transport order to a transport vehicle within a jurisdictional area, and assigns the first transport order to an empty transport vehicle when the first transport order occurs in a situation where the sum of the number of empty transport vehicles within the jurisdictional area and the number of empty transport vehicles outside the jurisdictional area is the first number, and the sum of the number of empty transport vehicles within the jurisdictional area and the number of empty transport vehicles outside the jurisdictional area A carrier system that does not assign the second carrier command to an empty carrier when the second carrier command occurs in a situation where the carrier is the first carrier. Claim 2 A transport vehicle system comprising a plurality of transport vehicles and a controller that assigns transport commands to the plurality of transport vehicles, wherein the controller assigns the first transport command to the empty transport vehicle when a first transport command of a first priority occurs in a situation where the number of empty transport vehicles is the first number, and does not assign the second transport command to the empty transport vehicle when a second transport command of a second priority lower than the first priority occurs in a situation where the number of empty transport vehicles is the first number, and the controller increases the priority of a transport command not assigned to any transport vehicle according to the elapsed time from the occurrence of the said transport command. Claim 3 In paragraph 2, the controller is a transport vehicle system that gradually increases priority according to the passage of time. Claim 4 In paragraph 2, the controller is a return vehicle system that allows for an increase in priority up to an upper limit that is set larger as the priority at the time of occurrence of a return command increases. Claim 5 A transport vehicle system according to any one of claims 1 to 4, wherein the controller does not assign the first transport command to the empty transport vehicle when the first transport command of the first priority occurs in a situation where the number of empty transport vehicles is less than the first number. Claim 6 A transport vehicle system according to any one of claims 1 to 4, wherein the controller assigns the second transport command to the empty transport vehicle when the second transport command of the second priority occurs in a situation where the number of empty transport vehicles is greater than the first number. Claim 7 A method for controlling a transport vehicle of a transport vehicle system comprising a plurality of transport vehicles and a controller for assigning transport commands to the plurality of transport vehicles, wherein the controller assigns the first transport command to an empty transport vehicle when a first transport command of a first priority occurs in a situation where the number of empty transport vehicles is the first number, and does not assign the second transport command to an empty transport vehicle when a second transport command of a second priority lower than the first priority occurs in a situation where the number of empty transport vehicles is the first number, and wherein the controller comprises a plurality of area controllers, and each of the plurality of area controllers assigns a transport command to a transport vehicle within a jurisdictional area, and assigns the first transport command to an empty transport vehicle when the first transport command occurs in a situation where the sum of the number of empty transport vehicles within the jurisdictional area and the number of empty transport vehicles outside the jurisdictional area is the first number, and the number of empty transport vehicles within the jurisdictional area and the empty transport vehicles outside the jurisdictional area A carrier control method comprising: not assigning the second carrier command to an empty carrier when the second carrier command occurs in a situation where the total number of carriers is the first carrier. Claim 8 A carrier control method for a carrier system comprising a plurality of carriers and a controller that assigns a carrier command to the plurality of carriers, wherein the controller assigns the first carrier command to the empty carrier when a first carrier command of a first priority occurs in a situation where the number of empty carriers is the first number, and does not assign the second carrier command to the empty carrier when a second carrier command of a second priority lower than the first priority occurs in a situation where the number of empty carriers is the first number, and the controller increases the priority of a carrier command not assigned to any carrier according to the elapsed time from the occurrence of the carrier command. Claim 9 delete Claim 10 delete

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