Control System

Abstract

To provide a technique capable of preventing a large delay from occurring in the conveyance of articles as a whole system even when a processing load of a control device is increased.SOLUTION: A control system 100 includes a control device 2 that executes a plurality of pieces of processing, including allocation processing that assigns a movement task T for transporting an article to one of a plurality of transport vehicles 1. When a processing load of the control device 2 exceeds a predetermined reference load using at least some of the plurality of pieces of processing executed by the control device 2, excluding the allocation processing as target processing, a restriction mode is set in which the execution of the target processing by the control device 2 is restricted, thereby reducing the load on the control device 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control system for controlling a plurality of transport vehicles that transport articles. [Background technology]

[0002] An example of such a control system is disclosed in Japanese Patent Laid-Open No. 2022-112098 (Patent Document 1). Hereinafter, in the description of this background art, the reference numerals in Patent Document 1 will be cited in parentheses. The control system (30) in Patent Document 1 includes a central control device (31) and a zone control device (32). The central control device (31) issues a transport request for an item (2) to the zone control device (32). The zone control device (32) assigns the transport request for the item (2) received from the central control device (31) to one of the transport vehicles (1) and commands the transport vehicle (1) to perform an operation according to the transport request for the item (2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-112098 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the processing load of the control device provided in the control system may become high due to the occurrence of a large number of movement tasks for transporting items (such as transport requests in Patent Document 1). When the processing load of the control device becomes high in this way, there may be a long-lasting delay in issuing instructions from the control device to the transport vehicle to transport items, which may cause a large delay in the transport of items in the entire system.

[0005] Therefore, it is desirable to realize a technology that can prevent large delays in the transport of items from occurring throughout the system, even when the processing load on the control device becomes high. [Means for solving the problem]

[0006] The control system of the present disclosure is a control system that controls a plurality of transport vehicles that transport goods, and is equipped with a control device that executes a plurality of processes, including an allocation process that assigns a movement task for transporting the goods to one of the plurality of transport vehicles.At least some of the processes executed by the control device, excluding the allocation process, are designated as target processes, and when the processing load of the control device exceeds a predetermined reference load, the control device is placed into a restriction mode that restricts the control device from executing the target processes, thereby reducing the load on the control device.

[0007] According to this configuration, when the processing load of the control device exceeds the reference load and enters the restricted mode, the load on the control device can be reduced by restricting the execution of the target process by the control device. Meanwhile, because the target process does not include the allocation process, the transport of items can continue even when the restricted mode is entered. Furthermore, instructions to the transport vehicle for transporting items can be issued by the control device, whose load has been reduced by restricting the execution of the target process. Therefore, even when the processing load of the control device becomes high enough to exceed the reference load, a prolonged delay in the instruction from the control device to the transport vehicle for transporting items can be avoided, making it less likely that a significant delay will occur in the transport of items throughout the system.

[0008] Further features and advantages of the control system will become apparent from the following description of the embodiments taken in conjunction with the drawings. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the layout of a transport facility to which a control system is applied. [Figure 2] A diagram showing an example of a transport vehicle. [Figure 3] Control block diagram according to an embodiment [Figure 4] Diagram of the review process [Figure 5] Another illustration of the review process [Figure 6] Illustration of the search range for transport vehicles [Figure 7] Explanation of empty transport vehicle movement process [Figure 8] Diagram of repetitive processing DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the control system will be described with reference to the drawings. As shown in Fig. 3, the control system 100 is a system that controls a plurality of transport vehicles 1 that transport items W (see Fig. 4). Although detailed illustration of the items W is omitted, the items W are, for example, FOUPs (Front Opening Unified Pods) that house semiconductor wafers.

[0011] The transport vehicle 1 travels along a travel path 6 (see FIG. 1) to transport an article W. The transport vehicle 1 is an automated transport vehicle. The travel path 6 may be formed physically or virtually. In this embodiment, the travel path 6 is physically formed by rails 7 (see FIG. 2), which will be described later. In FIG. 2, the travel path 6 shown in FIG. 1 is assumed to be formed along a ceiling 5, but the travel path 6 may also be formed on a floor surface or the like. As shown by the arrows in FIG. 1, the travel direction of the transport vehicle 1 at each portion of the travel path 6 is set to one direction. Note that in FIG. 1 and FIGS. 4 to 7, which will be referred to later, the transport vehicles 1 are divided into operating transport vehicles 1A, which are indicated by solid triangles, and empty transport vehicles 1B, which are indicated by hollow triangles. The operating transport vehicles 1A and empty transport vehicles 1B will be described later. In the example shown in FIG. 1, the travel path 6 includes a circular path 60 formed in a circular shape in a plan view, and a connecting path 61 connecting the multiple circular paths 60. The transport vehicle 1 can travel from a circular path 60 to another circular path 60 via a connecting path 61 .

[0012] As shown in FIG. 1, a plurality of stations 4 are set along the travel path 6. Although not shown, each station 4 is provided with an item support section for supporting the item W, and the item W is transferred between the transport vehicle 1 and the item support section at the station 4. The item support section may be, for example, a load port of a processing device that processes the item W (or the contents contained in the item W), an in / out port of a storage device that stores the item W, or a storage shelf that temporarily stores the item W. The item support section is, for example, arranged directly below the travel path 6.

[0013] The operation of the transport vehicle 1 includes a traveling operation of traveling along the travel path 6. In this embodiment, the transfer of the item W between the transport vehicle 1 and the item support section provided in the station 4 is performed by the transport vehicle 1 moving the item W. Therefore, the operation of the transport vehicle 1 includes a transfer operation of the item W at the station 4. Specifically, the operation of the transport vehicle 1 includes an operation of receiving the item W from the item support section at the station 4 and an operation of lowering the item W onto the item support section at the station 4.

[0014] FIG. 2 shows an example of a transport vehicle 1. The transport vehicle 1 shown in FIG. 2 includes a running section 10 that runs along a travel path 6 (see FIG. 1). The transport vehicle 1 further includes a main body 11 connected to the running section 10, and an article W is stored in the main body 11 and transported by the transport vehicle 1. The travel path 6 is formed using rails 7 (here, a pair of rails 7 arranged at a distance in the path width direction). The path width direction is a direction (left-right direction in FIG. 2) that is perpendicular to both the longitudinal direction and the up-down direction (vertical direction) of the travel path 6. In the example shown in FIG. 2, the rails 7 are suspended from a ceiling 5, and the travel path 6 is formed along the ceiling 5.

[0015] The traveling unit 10 shown in Fig. 2 includes traveling wheels 13 that roll on the traveling surface (here, the upper surface) of the rail 7, and a drive motor 12 that rotates the traveling wheels 13. The traveling wheels 13 are rotated by the drive motor 12, causing the traveling unit 10 to travel along the travel path 6. The traveling unit 10 shown in Fig. 2 further includes guide wheels 14 that roll on the guide surfaces (here, the side surfaces facing the path width direction) of the rail 7, and the traveling unit 10 travels along the rail 7 with the guide wheels 14 in contact with and guided by the guide surfaces of the rail 7.

[0016] In this embodiment, the transport vehicle 1 is equipped with a power receiving device 15 that receives power in a contactless manner from a power supply line 8 arranged along the travel path 6. In the example shown in FIG. 2, the power supply line 8 is arranged along the rails 7 that form the travel path 6. The transport vehicle 1 operates using the power received by the power receiving device 15. That is, the power received by the power receiving device 15 is supplied to an actuator (e.g., the above-mentioned drive motor 12) for operating the transport vehicle 1. The power receiving device 15 includes, for example, a pickup coil. AC power is induced in the pickup coil by a magnetic field generated around the power supply line 8 to which AC current is supplied. This AC power is converted, for example, to DC and supplied to an actuator for operating the transport vehicle 1.

[0017] As shown in Fig. 3, the control system 100 includes a control device 2. The control device 2 includes a processing unit such as a CPU (Central Processing Unit) and peripheral circuits such as a memory, and the functions of the control device 2 are realized by cooperation between these pieces of hardware and programs executed on the hardware such as the processing unit. A "device" such as the control device 2 or a higher-level control device 3 described below may not be a single device, but may be a collection of multiple devices that can communicate with each other. For example, the control device 2 may include multiple zone control devices that manage different zone areas A (described below).

[0018] The various technical features of the control device 2 described below can also be applied to an operation method of the control device 2 and a program for causing a computer to function as the control device 2, and such operation methods and programs, as well as a recording medium (a computer-readable recording medium such as an optical disk or flash memory) on which such a program is recorded, are also disclosed in this specification. The program for causing a computer to function as the control device 2 is provided, for example, by a recording medium on which the program is recorded, or is provided via a communication network, and the provided program is stored in a storage device that can be referenced by the control device 2.

[0019] The control device 2 is aware of the current position of each of the multiple guided vehicles 1. In this embodiment, the guided vehicles 1 are configured to recognize their own current position, and the control device 2 obtains information on the current position of each of the multiple guided vehicles 1 from each of the guided vehicles 1, thereby obtaining the current position of each of the multiple guided vehicles 1. Although details are omitted, for example, a configuration can be adopted in which detectable units (e.g., one-dimensional codes, two-dimensional codes, RF (Radio Frequency) tags, etc.) that hold position information are provided at multiple positions along the travel route 6, and the guided vehicles 1 recognize their own current positions by reading the position information held by the detectable units. Alternatively, a configuration can be adopted in which the guided vehicles 1 recognize their own current positions based on the output of a positioning device such as a GNSS (Global Navigation Satellite System) receiver.

[0020] 3, the control device 2 includes a processing execution unit 20, a control mode setting unit 22, and a processing load derivation unit 23. The processing execution unit 20 includes a target processing execution unit 21. Details of each functional unit will be described later, but the control device 2 includes multiple functional units in this manner. The multiple functional units included in the control device 2 are at least logically distinct, and do not necessarily need to be physically distinct.

[0021] The control device 2 (specifically, the process execution unit 20) executes multiple processes including an allocation process. The allocation process is a process of assigning a movement task T for transporting an item W to one of multiple transport vehicles 1. Here, a transport vehicle 1 to which a movement task T is assigned is referred to as an "operating transport vehicle 1A," and a transport vehicle 1 to which a movement task T is not assigned is referred to as an "empty transport vehicle 1B" (see Figure 1, etc.). The control device 2 instructs the transport vehicle 1 to which the movement task T is assigned to execute the movement task T. The transport vehicle 1 that receives the instruction operates to execute the movement task T. Specifically, a control unit (not shown) provided in the transport vehicle 1 controls the transport vehicle 1 to perform an operation to execute the movement task T.

[0022] The movement task T may be generated by the control device 2 or by another device capable of communicating with the control device 2. As shown in Fig. 3, in this embodiment, the upper control device 3 that manages transportation of the entire facility to which the control system 100 is applied is configured to generate the movement task T and transmit it to the control device 2. The upper control device 3 generates the movement task T, for example, based on the transportation schedule of the item W or in response to the occurrence of a transportation request for the item W.

[0023] The movement task T includes at least the first task out of the first task and the second task. In this embodiment, the movement task T includes both the first task and the second task.

[0024] The first task is a task of transporting an item W from its source to its destination. In this embodiment, the source and destination of the item W are station 4 (specifically, the aforementioned item support unit provided in station 4). Hereinafter, station 4 from which the item W is transported is referred to as the "source station 40," and station 4 to which the item W is transported is referred to as the "destination station 41" (see Figures 4 to 6). The first task includes information on the source station 40 and information on the destination station 41.

[0025] The guided vehicle 1 assigned the first task by the allocation process transports an item W from the source station 40 specified in the first task to the destination station 41 specified in the first task. At this time, the guided vehicle 1 travels to the source station 40, receives the item W at the source station 40, and then travels to the destination station 41, where the item W is unloaded from the guided vehicle 1. In the allocation process, for example, the first task is preferentially assigned to an empty guided vehicle 1B located near the source station 40. For example, if an empty guided vehicle 1B is waiting at the source station 40, the first task is assigned to the empty guided vehicle 1B. The first task can also be assigned to an operating guided vehicle 1A, in which case the operating guided vehicle 1A basically executes the movement tasks T assigned first.

[0026] The second task is a task of placing a transport vehicle 1 that is not transporting an item W at a location that is scheduled or predicted to be the source of the item W. The second task includes information about the location (in this embodiment, station 4) that is scheduled or predicted to be the source of the item W. In the allocation process, for example, the second task is preferentially allocated to an empty transport vehicle 1B that is located near station 4 that is scheduled or predicted to be the source of the item W.

[0027] The transport vehicle 1 to which the second task has been assigned by the allocation process travels to the station 4 designated in the second task, which is scheduled or predicted to be the origin of the item W. The transport vehicle 1 then waits at the station 4 until it is assigned another movement task T (for example, the first task having the station 4 as the origin). Note that, before the transport vehicle 1 arrives at the station 4 designated in the second task, another movement task T (for example, the first task having the station 4 as the origin) may be assigned to the transport vehicle 1.

[0028] In this embodiment, the second task includes both a task of placing a transport vehicle 1 that is not transporting an item W at a location that is expected to be the source of the item W (hereinafter referred to as the "first vehicle allocation task"), and a task of placing a transport vehicle 1 that is not transporting an item W at a location that is expected to be the source of the item W (hereinafter referred to as the "second vehicle allocation task"). In this embodiment, the movement task T is basically generated by the upper control device 3, but the second vehicle allocation task is generated by the control device 2.

[0029] If the item support unit provided in station 4 is a load port of a processing device, and the processing device is processing item W (or the contents contained in item W), when the processing is completed, a request is generated to remove the processed item W from the load port. Therefore, station 4 is a location that is scheduled to be the source of item W, and it is also possible to determine whether station 4 is scheduled to be the source of item W within a set time based on the status of the processing device (e.g., the progress of the processing). Also, if the item support unit provided in station 4 is an inbound / outbound port of a storage device, and a request to remove item W from the storage device is made, when the item W to be removed is transported from the storage unit of the storage device to the inbound / outbound port, a request is generated to remove item W from the inbound / outbound port. Therefore, station 4 is a location that is scheduled to be the source of item W, and it is also possible to determine whether station 4 is scheduled to be the source of item W within a set time based on the status of the storage device. The upper control device 3 identifies the station 4 that is scheduled to be the source of the item W in this manner, and generates a first vehicle allocation task, for example, to allocate a transport vehicle 1 that is not transporting the item W to the station 4 that is scheduled to be the source of the item W within a set time.

[0030] Furthermore, among the multiple stations 4, there may be a station 4 (hereinafter referred to as a "high frequency station") that is more frequently used as a source of an item W than the other stations 4. The control device 2 regards such a high frequency station as a station 4 that is predicted to be a source of an item W, and generates a second vehicle dispatch task to dispatch a transport vehicle 1 that is not transporting an item W to the station 4. For example, when an empty transport vehicle 1B is not waiting at the high frequency station, the control device 2 generates a second vehicle dispatch task to dispatch a transport vehicle 1 that is not transporting an item W to the high frequency station. The high frequency station is, for example, set in advance by a worker.

[0031] In this embodiment, the multiple processes executed by the control device 2 (specifically, the process execution unit 20) include at least one of (here, both of) an abnormality response process and an entry restriction process. The abnormality response process is a process for responding to an abnormality that occurs in the transport vehicle 1. The control device 2 executes the abnormality response process when an abnormality occurs in the transport vehicle 1. The abnormality response process is, for example, a process for stopping the transport vehicle 1 in which the abnormality occurred, or a process for moving the transport vehicle 1 in which the abnormality occurred to a location (for example, an evacuation lane, a maintenance area, etc.) that is less likely to interfere with the travel of other transport vehicles 1.

[0032] The entry restriction process is a process of restricting the entry of the transport vehicle 1 into a specific area (hereinafter referred to as an "entry restriction area"). The control device 2 sets, as an entry restriction area, an area where there is a route where other transport vehicles 1 cannot travel due to the presence of a transport vehicle 1 that has stopped abnormally, or an area where the number of transport vehicles 1 has reached an upper limit set to ensure smooth travel of the transport vehicles 1. When setting an entry restriction area, the control device 2 executes the entry restriction process for the entry restriction area. The transport vehicle 1 travels along a travel route set to execute the movement task T, but the control device 2 restricts the entry of the transport vehicle 1 into the entry restriction area by prohibiting the setting of a travel route that enters the entry restriction area. In this embodiment, the travel route of the transport vehicle 1 to execute the movement task T is set by the control device 2 and transmitted to the transport vehicle 1. The transport vehicle 1 holds map information, which is information on the layout of the travel route 6, and travels along the set travel route based on its own current position and the map information.

[0033] As described above, in this embodiment, the transport vehicle 1 is equipped with a power receiving device 15 that receives power in a contactless manner from a power supply line 8 arranged along the travel route 6. In this embodiment, the area in which the transport vehicle 1 travels is divided into a plurality of power supply areas, and power is supplied to the transport vehicle 1 in each of the power supply areas. The power supply areas may be divided in the same way as the partitioned area A (see FIG. 1) described below. If many transport vehicles 1 enter one power supply area, the power supply to each transport vehicle 1 may become insufficient due to limitations on the power supply capacity. Therefore, an upper limit on the number of transport vehicles 1 determined by the limitations on the power supply capacity may be set for each power supply area. In this case, the control device 2 sets a power supply area in which the number of transport vehicles 1 has reached the upper limit as an entry restricted area.

[0034] Here, at least some of the processes excluding the allocation process among the multiple processes executed by the control device 2 are referred to as "target processes." The target processes are executed by a target process execution unit 21 included in the process execution unit 20. In this embodiment, the abnormality response process and the entry restriction process are not included in the target processes, as is the allocation process.

[0035] This control system 100 is configured to reduce the load on the control device 2 by switching to a restricted mode that restricts the execution of a target process by the control device 2 when the processing load of the control device 2 exceeds a predetermined reference load (hereinafter referred to as a "first reference load"). In this embodiment, a processing load derivation unit 23 included in the control device 2 derives the processing load of the control device 2, and a control mode setting unit 22 included in the control device 2 sets the control mode (operation mode) of the control device 2 (see FIG. 3). Hereinafter, a control mode that is not the restricted mode will be referred to as a "normal mode."

[0036] When the control mode of the control device 2 is set to the normal mode and the processing load of the control device 2 exceeds a first reference load, the control mode setting unit 22 changes the control mode of the control device 2 from the normal mode to the restricted mode. Furthermore, when the control mode of the control device 2 is set to the restricted mode and the processing load of the control device 2 becomes equal to or less than a second reference load, the control mode setting unit 22 changes the control mode of the control device 2 from the restricted mode to the normal mode. The second reference load is set to a value equal to or less than the first reference load, and in this embodiment, is set to a value smaller than the first reference load.

[0037] In this embodiment, the processing load derivation unit 23 derives the processing load of the control device 2 based on a value obtained by dividing the total number of uncompleted movement tasks T held by the control device 2 by the total number of guided vehicles 1 controlled by the control device 2. For example, the processing load derivation unit 23 derives the above value as is as the processing load of the control device 2. The guided vehicles 1 controlled by the control device 2 are, for example, guided vehicles 1 that are under the control of the control device 2, exist on the travel route 6, are in an activated state, and are able to communicate with the control device 2. A guided vehicle 1 that has been removed from the travel route 6 due to an abnormality, a malfunction, or the like is not included in the guided vehicles 1 controlled by the control device 2.

[0038] In this embodiment, the control device 2 holds a movement task T (specifically, a first task and a first dispatch task) generated by the upper control device 3 and transmitted to the control device 2, and a movement task T (specifically, a second dispatch task) generated by the control device 2. The first task is determined to be completed at a point in time after the first task is assigned to the transport vehicle 1 (for example, at a point in time when the article W is unloaded from the transport vehicle 1 at the destination station 41 specified in the first task). Furthermore, the second task (the first dispatch task or the second dispatch task) is determined to be completed at a point in time after the second task is assigned to the transport vehicle 1 (for example, at a point in time when the transport vehicle 1 arrives at the station 4 specified in the second task).

[0039] Examples of processes executed by the control device 2 (specifically, the process execution unit 20) include a review process, a search process, a sequential allocation process, a repeat process, a reallocation process, an empty transport vehicle movement process, a vehicle allocation task acceptance process, a vehicle allocation task generation process, a map distribution process, a route resetting process, a normal kickout process, an allocation limitation process, and an evacuation destination limitation process, which are described below. The contents of each of these processes, as well as the contents of limitations in the limitation mode when the process is included in the target process, are described below.

[0040] <Review process> The review process is a process of reassigning a second transport vehicle 1, which is a transport vehicle 1 different from the first transport vehicle, to a movement task T that has already been assigned to a first transport vehicle, which is one of the transport vehicles 1, by the allocation process. FIGS. 4 and 5 show two examples of the review process performed for the first task. In these examples, the operating transport vehicle 1A corresponds to the "first transport vehicle," and the empty transport vehicle 1B corresponds to the "second transport vehicle." The example shown in FIG. 4 shows a situation in which, while the operating transport vehicle 1A to which the movement task T (here, the first task) has been assigned is traveling toward the origin station 40, the transport vehicle 1 changes from the operating transport vehicle 1A to an empty transport vehicle 1B near the origin station 40, and the movement task T is reassigned to the empty transport vehicle 1B that can reach the origin station 40 sooner. The example shown in Figure 5 shows a situation in which, while an operating transport vehicle 1A assigned two movement tasks T (here, the first task) is traveling toward the destination station 41 specified in the first movement task T, the transport vehicle 1 changes from an operating transport vehicle 1A to an empty transport vehicle 1B near the source station 40 specified in the second movement task T, and the second movement task T is reassigned to the empty transport vehicle 1B, which can reach the source station 40 more quickly.

[0041] When the review process is included in the target process, execution of the review process by the control device 2 is prohibited in the restricted mode. Note that in a situation where many movement tasks T occur and the restricted mode is in effect, there are few empty transport vehicles 1B, so even if the review process is executed, it may not be possible to find a more suitable transport vehicle 1, which may unnecessarily increase the load on the control device 2. By prohibiting execution of the review process in the restricted mode, it is possible to avoid unnecessarily increasing the load on the control device 2 as described above.

[0042] <Search process> The search process is a process for searching for a guided vehicle 1 to which a movement task T is assigned in the allocation process. For the first task, the origin station 40 specified in the first task is set as a reference point, and for the second task, the station 4 specified in the second task (the station 4 scheduled or predicted to be the origin of the item W) is set as a reference point. The range within which the search for the guided vehicle 1 in the search process (hereinafter referred to as the "search range") is set to include the reference points. FIG. 6 shows an example of the search range set for the first task (i.e., the search range with the origin station 40 as the reference point). In the example shown in FIG. 6, it is assumed that the size of the search range is defined by the number of circular routes 60 included in the search range. A first search range S1 including five circular routes 60 is wider than a second search range S2 including three circular routes 60. Note that the size of the search range may also be defined by the distance to the reference point (the distance along the travel route 6 or the straight-line distance).

[0043] When the search process is included in the target process, in the limited mode, the range in which the guided vehicle 1 is searched for in the search process is set narrower than when the limited mode is not set (here, when the normal mode is set). The search range in the limited mode is set to include the circular route 60 on which the reference point is located and the circular routes 60 on both sides of it, for example, as in the second search range S2 shown in Fig. 6. In addition, the search range in the normal mode is set to the entire area in which the guided vehicle 1 travels (the entire layout of the travel route 6).

[0044] <Sequential allocation process> The sequential allocation process is a process in which the guided vehicle 1 sequentially executes the allocation process for one or more movement tasks T to which the guided vehicle 1 has not been assigned. The sequential allocation process is executed until a termination condition is met, and when the termination condition is met, the sequential allocation process is terminated. The control device 2 repeatedly executes the sequential allocation process.

[0045] When a sequential allocation process that is repeatedly executed is included in the target process, in the limited mode, the termination condition for the sequential allocation process is set so that the number of times the allocation process can be executed is less than when the limited mode is not used (here, when the normal mode is used). Here, a movement task T to which a guided vehicle 1 is not assigned is defined as an "unassigned task," the "first condition" is that a guided vehicle 1 has been assigned to all unassigned tasks held by the control device 2, and the "second condition" is that the number of times the allocation process has been executed has reached the above-mentioned number of times it can be executed. The control device 2 terminates the sequential allocation process when either the first condition or the second condition is satisfied. Note that the number of times the allocation process has been executed or the number of times it can be executed may be the number of times an allocation process in which a guided vehicle 1 to be assigned was not found. Furthermore, the number of times it can be executed in the normal mode may be set to infinity (i.e., no upper limit).

[0046] <Repeat processing> The repetitive process is a process of repeatedly executing a sequential allocation process. In this embodiment, as shown in FIG. 8, the control device 2 repeatedly executes the sequential allocation process with an interval period P therebetween. As shown in FIG. 8, the execution time of the sequential allocation process (in the example shown in FIG. 8, the time from time t1 to time t2, the time from time t3 to time t4, and the time from time t5 to time t6) may change each time, but the length of the interval period P may be fixed or variable. During this interval period P, for example, a process of setting or resetting a travel route for executing the movement task T, a process of issuing instructions (such as an instruction to execute the movement task T) to the guided vehicle 1 to which the movement task T has been assigned, a process of receiving the movement task T from the upper control device 3, an abnormality response process, and an entry restriction process are executed. When the repetitive process is included in the target process, in the restricted mode, the time from the end of the sequential allocation process in the repetitive process to the start of the next sequential allocation process (i.e., the length of the interval period P) is made longer than in the non-restricted mode (here, in the normal mode).

[0047] <Reassignment process> The reallocation process is a process of re-executing the allocation process for a movement task T to which a guided vehicle 1 could not be assigned in the allocation process. When the reallocation process is included in the target processes, in the restricted mode, the period from the execution of the previous allocation process to the execution of the reallocation process is made longer than when the restricted mode is not being used (here, when the normal mode is being used). For example, in the normal mode, the reallocation process for a movement task T to which a guided vehicle 1 could not be assigned in the allocation process is executed in the sequential allocation process that follows one after the sequential allocation process in which the allocation process was performed, and in the restricted mode, the reallocation process for a movement task T to which a guided vehicle 1 could not be assigned in the allocation process is executed in the sequential allocation process that follows two or more after the sequential allocation process in which the allocation process was performed.

[0048] <Empty transport vehicle movement processing> The control device 2 may be configured to manage an area in which the transport vehicles 1 travel by dividing it into multiple divided areas A. FIG. 1 shows an example of a divided area A, which includes five divided areas A: a first divided area A1, a second divided area A2, a third divided area A3, a fourth divided area A4, and a fifth divided area A5. The empty transport vehicle movement process is a process of moving empty transport vehicles 1B to bring the number of empty transport vehicles 1B in each of the multiple divided areas A closer to a target value set for each of the multiple divided areas A. FIG. 7 shows an example of the empty transport vehicle movement process. In FIG. 7, it is assumed that the target value set for each divided area A is two vehicles. In this case, by moving one empty transport vehicle 1B from the third divided area A3 to the second divided area A2 as shown by the arrow in the figure, the number of empty transport vehicles 1B in each of the five divided areas A becomes two.

[0049] When the empty transport vehicle movement process is included in the target process, in the restricted mode, the control device 2 prohibits the empty transport vehicle movement process from being executed, or the maximum movement distance of the empty transport vehicle 1B permitted in the empty transport vehicle movement process is set shorter than when the restricted mode is not being used (here, when the normal mode is being used). The above maximum movement distance in the normal mode may be set to infinity (i.e., no upper limit). Note that in a situation where many movement tasks T are generated and the restricted mode is being used, there are few empty transport vehicles 1B, so that the movement task T is assigned to an empty transport vehicle 1B that is moving by the empty transport vehicle movement process, and this movement is likely to be wasted. In the restricted mode, by restricting the execution of the empty transport vehicle movement process as described above, it is possible to make such wasted movement of the transport vehicle 1 less likely to occur.

[0050] <Dispatch task acceptance process> The vehicle allocation task acceptance process is a process for accepting the first vehicle allocation task received from the upper control device 3 as the travel task T to be assigned. By executing the vehicle allocation task acceptance process, the first vehicle allocation task can be executed by the guided vehicle 1 as described above. When the vehicle allocation task acceptance process is included in the target processes, execution of the vehicle allocation task acceptance process by the control device 2 is prohibited in the restricted mode. Therefore, the first vehicle allocation task is not executed in the restricted mode. In this case, the control device 2, for example, discards the first vehicle allocation task received from the upper control device 3. Note that, in a situation where many travel tasks T are generated and the restricted mode is active, allocating a vehicle 1 that is not transporting an item W to the first task rather than the first vehicle allocation task is likely to reduce the load on the control device 2. In addition to being able to reduce the number of processes executed by the control device 2, it is preferable to prohibit execution of the vehicle allocation task acceptance process in the restricted mode from this point of view. For the same reason, it is preferable to prohibit execution of the vehicle allocation task generation process in the restricted mode, as described below.

[0051] <Vehicle allocation task generation process> The vehicle allocation task generation process is a process for generating a second vehicle allocation task. By executing the vehicle allocation task generation process, the second vehicle allocation task can be executed by the transport vehicle 1 as described above. If the vehicle allocation task generation process is included in the target process, execution of the vehicle allocation task generation process by the control device 2 is prohibited in the restricted mode. Therefore, the second vehicle allocation task is not executed in the restricted mode.

[0052] <Map distribution process> The map distribution process is a process of distributing updated map information, which is information about the layout of the travel route 6, to the transport vehicle 1 when the map information is updated. The map information distributed to the transport vehicle 1 is used when the transport vehicle 1 travels along the travel route. When the map distribution process is included in the target processes, execution of the map distribution process by the control device 2 is prohibited in the restricted mode. The map distribution process performed when the map information is updated is a process that is not directly related to the transportation of the item W. In view of this, it is preferable to prohibit execution of the map distribution process in the restricted mode and prioritize reducing the load on the control device 2. Note that even in the restricted mode, the map distribution process can be exceptionally executed for transport vehicles 1 located in a specific area. This specific area is, for example, an area near the boundary between an area under the jurisdiction of one control device 2 and an area under the jurisdiction of another control device 2 when multiple control devices 2 are provided and each control device 2 is responsible for a different area.

[0053] <Route reconfiguration process> As described above, in this embodiment, the travel route of the transport vehicle 1 for executing the movement task T is set by the control device 2. That is, the control device 2 (specifically, the processing execution unit 20) executes a route setting process for setting a travel route of the transport vehicle 1 for executing the movement task T. The route resetting process is a process for re-executing the route setting process for the movement task T whose travel route has been set by the route setting process. By executing the route resetting process, a more appropriate travel route can be set for the movement task T according to the transport status of the item W in the transport facility at that time, thereby improving the processing of the movement task T.

[0054] When the route resetting process is included in the target processes, in the restricted mode, the period from the previous execution of the route resetting process to the next execution of the route resetting process is made longer than when the restricted mode is not in effect (here, when the normal mode is in effect). In a situation where many movement tasks T occur and the restricted mode is in effect, even if the route resetting process is executed when the time that has elapsed since the previous execution of the route resetting process is short, there is little change in the conveyance status of the item W in the conveyance facility, and the travel route will not be changed, which may unnecessarily increase the load on the control device 2. By restricting the execution of the route resetting process in the restricted mode as described above, the frequency of execution of the route resetting process in the restricted mode can be reduced, thereby reducing the load on the control device 2.

[0055] <Normal eviction process> The normal eviction process is a process in which, in at least one of the cases where the destination specified in the first task is on the travel route set for the other transport vehicle 1 and where the destination specified in the first task is a location where waiting for the transport vehicle 1 is prohibited, the transport vehicle 1 that has completed the first task is evacuated from the destination and moved (evicted) to a location that is off the travel route set for the other transport vehicle 1 and where waiting for the transport vehicle 1 is not prohibited. For example, the location where waiting for the transport vehicle 1 is prohibited is station 4 where goods W are frequently transferred, and the location where waiting for the transport vehicle 1 is not prohibited is other stations 4.

[0056] If the normal eviction process is included in the target process, the control device 2 is prohibited from executing the normal eviction process in the restricted mode. Then, in the restricted mode, the control device 2 executes the simplified eviction process instead of the normal eviction process. The simplified eviction process is a process in which the guided vehicle 1 that has completed the first task is evacuated from the destination specified in the first task unconditionally, or when the destination specified in the first task is a location where the guided vehicle 1 is prohibited from waiting, and the guided vehicle 1 is evacuated to a location where the guided vehicle 1 is not prohibited from waiting. Unlike the normal eviction process, the simplified eviction process does not determine whether the destination specified in the first task or the destination of the evacuation move is on a travel route set for another guided vehicle 1. Therefore, by executing the simplified eviction process instead of the normal eviction process in the restricted mode, the load related to the eviction process can be reduced, thereby reducing the load on the control device 2.

[0057] <Allocation limit processing> The allocation limitation process is a process in which a first task, the source and destination of which are locations within a specific area (hereinafter referred to as the "target area"), is assigned only to one or more local guided vehicles, which are part of the guided vehicles 1, or is preferentially assigned to the local guided vehicles. The target area can be, for example, an area that includes only a specific circular route 60, or it may be an area common to any of the above-mentioned divided areas A. When the allocation limitation process is included in the target process, execution of the allocation limitation process by the control device 2 is prohibited in the restricted mode. Since the allocation limitation process and the evacuation destination limitation process described below are additional processes, prohibiting the execution of these processes in the restricted mode reduces the number of processes that the control device 2 executes in the restricted mode, thereby reducing the load on the control device 2.

[0058] <Recovery destination limited processing> The evacuation destination limiting process is a process for limiting the location of the destination of the evacuation movement to a location within the target area (station 4 in this embodiment) when the transport vehicle 1 that performs the evacuation movement in the normal eviction process or the simplified eviction process described above is a local transport vehicle. When the evacuation destination limiting process is included in the target process, execution of the evacuation destination limiting process by the control device 2 is prohibited in the restricted mode.

[0059] The embodiments disclosed in this specification are merely examples in all respects, and various modifications can be made as appropriate within the scope of the present disclosure.

[0060] [Summary of the above embodiment] The control system described above will now be outlined.

[0061] A control system for controlling a plurality of transport vehicles for transporting goods includes a control device that executes a plurality of processes, including an allocation process that assigns a movement task for transporting the goods to one of the plurality of transport vehicles, and at least some of the processes executed by the control device, excluding the allocation process, are designated as target processes, and when the processing load of the control device exceeds a predetermined reference load, the control device is placed into a restriction mode that restricts the control device from executing the target processes, thereby reducing the load on the control device.

[0062] According to this configuration, when the processing load of the control device exceeds the reference load and enters the restricted mode, the load on the control device can be reduced by restricting the execution of the target process by the control device. Meanwhile, because the target process does not include the allocation process, the transport of items can continue even when the restricted mode is entered. Furthermore, instructions to the transport vehicle for transporting items can be issued by the control device, whose load has been reduced by restricting the execution of the target process. Therefore, even when the processing load of the control device becomes high enough to exceed the reference load, a prolonged delay in the instruction from the control device to the transport vehicle for transporting items can be avoided, making it less likely that a significant delay will occur in the transport of items throughout the system.

[0063] Here, the movement task includes at least the first task of transporting the item from the source to the destination, and the second task of placing the transport vehicle that is not transporting the item at a location that is scheduled or predicted to be the source of the item, and it is preferable that the processing load is derived based on the value obtained by dividing the total number of incomplete movement tasks held by the control device by the total number of transport vehicles controlled by the control device.

[0064] According to this configuration, the processing load of the control device can be quantified relatively easily, making it easy to determine whether the processing load of the control device has exceeded the reference load.

[0065] In addition, the multiple processes executed by the control device include at least one of an abnormality response process to respond to an abnormality that occurs in the transport vehicle and an entry restriction process to restrict the entry of the transport vehicle into a specific area, and it is preferable that the target processes do not include the abnormality response process and the entry restriction process.

[0066] If an abnormality occurs in a transport vehicle and processing is not performed to address the abnormality, delays in transport of items may occur, such as requiring the transport route to avoid the transport vehicle. Furthermore, if there is an area where access to transport vehicles should be restricted, and the transport vehicle enters the area, smooth travel of the transport vehicle may become difficult in the area, resulting in delays in transport of items. In this regard, according to the present configuration, the target processing does not include the abnormality response processing and the entry restriction processing, and therefore, even in the restricted mode, the abnormality response processing and the entry restriction processing can be executed as needed, making it less likely that delays will occur in transport of items.

[0067] Furthermore, it is preferable that the target process includes a review process for reassigning a second transport vehicle, which is a transport vehicle different from the first transport vehicle, to the movement task to which a first transport vehicle, which is one of the transport vehicles, has already been assigned by the allocation process, and that execution of the review process is prohibited in the restricted mode.

[0068] By executing the above-described review process, a movement task that has already been assigned to a transport vehicle can be reassigned to a more appropriate transport vehicle, thereby improving the processing efficiency of the movement task. However, the review process is not essential for transporting items. In this regard, according to the present configuration, the execution of the review process is prohibited in the restricted mode, so that the number of processes executed by the control device in the restricted mode can be reduced, thereby reducing the load on the control device.

[0069] In addition, the target processing includes a search process for searching for the transport vehicle to which the movement task is to be assigned in the allocation processing, and in the restricted mode, it is preferable to set the range for searching for the transport vehicle in the search process to be narrower than when the restricted mode is not in effect.

[0070] For example, a configuration is conceivable in which the search range for a guided vehicle is expanded in one search process until a guided vehicle to which a movement task can be assigned (hereinafter referred to as a "target guided vehicle") is found, and if the target guided vehicle is not found even when the search range reaches a set upper limit, the search process is terminated. In this case, the processing load for one search process tends to increase as the range set as the upper limit of the search range becomes wider. In particular, in a situation where many movement tasks are occurring, there may be few guided vehicles to which a movement task is not assigned, and it may be possible that no guided vehicle to which a movement task is not assigned exists within the range set as the upper limit of the search range. Therefore, the load associated with one search process tends to increase as the range set as the upper limit of the search range becomes wider. In this regard, according to this configuration, the range for searching for a guided vehicle is set narrow in the limited mode, thereby reducing the load associated with one search process and reducing the load on the control device.

[0071] Furthermore, the target process includes a sequential allocation process that is repeatedly executed, and the sequential allocation process is a process that sequentially executes the allocation process for one or more movement tasks to which the transport vehicle is not assigned until an end condition is met, and in the restricted mode, it is preferable to set the end condition in the sequential allocation process so that the number of times the allocation process can be executed is fewer than when the restricted mode is not used.

[0072] The load associated with one sequential allocation process increases as the number of movement tasks to which no guided vehicle is currently assigned (hereinafter referred to as "unassigned tasks") increases, with the number of executable times of the allocation process being the upper limit. In particular, in a situation where many movement tasks are occurring, the number of unassigned tasks at that time increases and there are few guided vehicles to which no movement tasks are assigned, so it may not be possible to assign guided vehicles to all of the unassigned tasks. In this regard, according to this configuration, in the limited mode, the termination condition of the sequential allocation process is set so as to reduce the executable times of the allocation process, thereby reducing the load associated with one sequential allocation process and the load on the control device.

[0073] Furthermore, the target process includes a repetitive process that repeatedly executes a sequential allocation process, and the sequential allocation process is a process that sequentially executes the allocation process for one or more of the movement tasks to which the transport vehicle is not assigned, and in the restricted mode, it is preferable that the time from the end of the sequential allocation process in the repetitive process to the start of the next sequential allocation process be longer than when the restricted mode is not used.

[0074] When a control device repeatedly executes sequential allocation processing, processing other than the allocation processing (for example, processing to receive a movement task from a higher-level control device, processing to give instructions to a transport vehicle to which a movement task has been assigned, the abnormality response processing and entry restriction processing described above, etc.) is executed during the interval period from the end of a sequential allocation processing to the start of the next sequential allocation processing. If the interval period is short compared to the number of processing other than the allocation processing, there is a possibility that incomplete processing will accumulate and the load on the control device will increase. In this regard, according to the present configuration, the interval period can be lengthened in the restriction mode, thereby preventing the accumulation of incomplete processing and reducing the load on the control device.

[0075] In addition, the target process includes a reallocation process in which the allocation process is executed again for the movement task to which the transport vehicle could not be assigned in the allocation process, and in the restricted mode, it is preferable to make the period from the previous execution of the allocation process to the execution of the reallocation process longer than when the restricted mode is not in effect.

[0076] A situation in which a transport vehicle cannot be assigned to a travel task in the allocation process may occur, for example, when there are many travel tasks for transporting goods and there are few transport vehicles to which a travel task has not been assigned. In such a case, even if a reallocation process is performed when a short time has elapsed since the execution of the allocation process, a transport vehicle to which a travel task can be assigned may not be found again, which may unnecessarily increase the load on the control device. In this regard, according to the present configuration, the period from the execution of the previous allocation process to the execution of the reallocation process is extended in the limited mode, so that the frequency of execution of the reallocation process in the limited mode can be reduced, thereby reducing the load on the control device.

[0077] In addition, the control device divides the area in which the transport vehicles travel into a plurality of partitioned areas and manages them, and the target process includes an empty transport vehicle movement process that moves empty transport vehicles, which are transport vehicles that are not assigned the movement task, to bring the number of empty transport vehicles in each of the plurality of partitioned areas closer to a target value set for each of the plurality of partitioned areas, and in the restricted mode, it is preferable that the empty transport vehicle movement process is prohibited, or the maximum movement distance of the empty transport vehicles allowed in the empty transport vehicle movement process is shorter than when the restricted mode is not in effect.

[0078] By executing the above-described empty vehicle movement process, empty vehicles can be distributed and allocated among multiple partitioned areas. Therefore, regardless of which partitioned area the origin of an item specified in a newly generated movement task is located in, an empty vehicle located relatively close to the origin can be assigned to the movement task. However, the empty vehicle movement process is not a necessary process for transporting items. Furthermore, as the distance to move an empty vehicle in the empty vehicle movement process increases, the load associated with the process of searching for a path along which the empty vehicle should be moved increases. In this regard, according to this configuration, in the limited mode, the empty vehicle movement process is prohibited or the maximum travel distance of an empty vehicle permitted in the empty vehicle movement process is shortened. This reduces the number of processes executed by the control device in the limited mode, or reduces the load associated with empty vehicle movement control, thereby reducing the load on the control device.

[0079] It is sufficient for the control system according to the present disclosure to achieve at least one of the above-described effects. [Explanation of symbols]

[0080] 1: Transport vehicle 1B: Empty transport vehicle 2: Control device 100: Control System A: Area T: Movement task W:Goods

Claims

1. A control system for controlling a plurality of transport vehicles that transport articles, a control device that executes a plurality of processes, including an allocation process that allocates a movement task for transporting the item to one of the plurality of transport vehicles; Among the plurality of processes executed by the control device, at least a part of the processes excluding the allocation process is set as a target process, A control system that reduces the load on the control device by switching the control device to a restricted mode that restricts the control device from executing the target process when the processing load on the control device exceeds a predetermined reference load.

2. the movement task includes at least a first task of transporting the item from a transport source to a transport destination, and a second task of placing the transport vehicle that is not transporting the item at a location that is scheduled or predicted to be the transport source of the item, The control system according to claim 1, wherein the processing load is calculated based on a value obtained by dividing the total number of incomplete movement tasks held by the control device by the total number of transport vehicles controlled by the control device.

3. the plurality of processes executed by the control device include at least one of an abnormality response process for responding to an abnormality that has occurred in the transport vehicle and an entry restriction process for restricting entry of the transport vehicle into a specific area; The control system according to claim 1 , wherein the target processes do not include the abnormality response process and the entry restriction process.

4. the target process includes a review process of reassigning a second transporting vehicle, which is a transporting vehicle different from a first transporting vehicle, to the movement task to which a first transporting vehicle, which is one of the transporting vehicles, has already been assigned by the assignment process; The control system according to claim 1 or 2, wherein execution of the review process is prohibited in the restricted mode.

5. the target processing includes a search processing for searching for the transportation vehicle to which the movement task is to be assigned in the assignment processing, 3. The control system according to claim 1, wherein in the limited mode, a range in which the guided vehicle is searched for in the search process is set to be narrower than when the limited mode is not in effect.

6. The target process includes a sequential allocation process that is repeatedly executed, the sequential allocation process is a process of sequentially executing the allocation process for one or more of the movement tasks to which the transporting vehicle is not assigned until a termination condition is satisfied, 3. The control system according to claim 1, wherein in the limited mode, the termination condition for the sequential allocation process is set so that the number of times the allocation process can be executed is smaller than when the limited mode is not in effect.

7. the target process includes a repeat process that repeatedly executes a sequential allocation process, the sequential allocation process is a process of sequentially executing the allocation process for one or more of the movement tasks to which the transporting vehicle is not assigned, The control system according to claim 1 or 2, wherein in the limited mode, a time period from the end of the sequential allocation process in the repetitive process to the start of the next sequential allocation process is made longer than when the limited mode is not in effect.

8. the target process includes a reallocation process of re-executing the allocation process for the movement task to which the transport vehicle could not be allocated in the allocation process, The control system according to claim 1 or 2, wherein in the limited mode, a period from the previous execution of the allocation process to the execution of the reallocation process is made longer than when the limited mode is not in the limited mode.

9. the control device divides an area in which the transport vehicle travels into a plurality of partitioned areas and manages the divided areas; the target process includes an empty transport vehicle movement process that moves an empty transport vehicle, which is a transport vehicle to which the movement task is not assigned, to bring the number of the empty transport vehicles in each of the plurality of divided areas closer to a target value set for each of the plurality of divided areas; A control system as described in claim 1 or 2, wherein in the restricted mode, the empty transport vehicle movement process is prohibited, or the maximum movement distance of the empty transport vehicle allowed in the empty transport vehicle movement process is made shorter than when the restricted mode is not in effect.

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