Goods handling equipment

Abstract

To achieve conveyance of an article having high rationality.SOLUTION: A control system executes selection processing for calculating an evaluation cost Cx of respective conveyance vehicles 1 by using a cost which is a value about a factor that affects a movement time of the conveyance vehicle 1 and becomes larger as the movement time becomes long, and selecting, as a target conveyance vehicle 1, the conveyance vehicle 1 having the smallest evaluation cost Cx when the target conveyance vehicle 1 to perform conveyance processing is selected from among the plurality of conveyance vehicles 1 holding no articles. In the selection processing when a specific holding part is made to be a conveyance source F, the evaluation cost Cx is calculated on the basis of both a reception cost Cr corresponding to a movement time from a current position P of the conveyance vehicle 1 to the conveyance source F and a delivery cost Cg corresponding to a movement time from the conveyance source F of the conveyance vehicle 1 to a conveyance destination T.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an article conveyance facility including a plurality of conveyance vehicles that move along a predetermined movement route to convey articles, and a control system that causes the conveyance vehicles to perform a conveyance process in which a conveyance source and a conveyance destination of the articles are specified.

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2020-66499 (Patent Document 1) discloses a conveyance system used in a factory for manufacturing semiconductor products. In such a conveyance system, in order to perform various processes on articles, the articles are conveyed between processes by conveyance vehicles. Generally, based on a conveyance command issued by a system controller that manages the system, a conveyance vehicle receives the specified article at a specified conveyance source and conveys the article to a specified conveyance destination.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when selecting a conveyance vehicle for conveying an article from among a plurality of conveyance vehicles, in order to reasonably convey the article from the perspective of conveyance time etc., the conveyance vehicle located at the position closest to the place (conveyance source) where the target article is stored is often selected. However, when the structure of the route is complex or there are restrictions on the movement of the conveyance vehicle on the route etc., there may be a plurality of routes for the conveyance vehicle from the conveyance source to the conveyance destination after receiving the article, that is, the route from the conveyance source to the conveyance destination. Therefore, when the distance between the conveyance source and the conveyance vehicle is used solely as a selection criterion for selecting a conveyance vehicle for conveying an article, reasonable conveyance of the article may not be achieved.

[0005] In light of the above circumstances, there is a need for goods handling equipment that can achieve highly efficient goods transport. [Means for solving the problem]

[0006] An article transport system comprising: a plurality of transport vehicles that transport articles by moving along a predetermined route; and a control system that causes the transport vehicles to perform transport processing where the source and destination of the articles are specified, Multiple article holding units capable of holding the article and allowing the transport vehicle to receive the article are arranged at multiple locations along the aforementioned movement path. At least one of the multiple article holding units is a specific holding unit that allows the transfer of the article from the transport vehicle located in any of the multiple specific sections of the transport path, The control system is configured to perform a selection process in which, when selecting a target transport vehicle from among a plurality of transport vehicles that do not hold the item, it calculates the evaluation cost of each transport vehicle using a cost that is a value for a factor affecting the travel time of the transport vehicle and increases as the travel time increases, and selects the transport vehicle with the smallest evaluation cost as the target transport vehicle. In the selection process when the specified holding unit is the source of transport, the evaluation cost is calculated based on both the receiving cost, which is the cost corresponding to the travel time from the current position of the transport vehicle to the source of transport, and the delivery cost, which is the cost corresponding to the travel time from the source of transport to the destination of transport.

[0007] According to this configuration, when a specific holding unit is designated as the source of a transport vehicle, the target transport vehicle to perform the transport process can be selected based on both the cost corresponding to the travel time from the transport vehicle's current position to the source and the cost corresponding to the travel time from the transport vehicle's source to the destination. In other words, the situation after the transport vehicle receives the goods at the source can also be used as a criterion for selecting the target transport vehicle. Therefore, this configuration makes it possible to achieve highly rational goods transport.

[0008] Further features and advantages of the technology relating to this disclosure will become clearer from the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0009] [Figure 1] Plan view of goods handling equipment [Figure 2] Front view showing the article holding section [Figure 3] Front view showing the specific holding part [Figure 4] A conceptual diagram illustrating receiving costs and delivery costs. [Figure 5] Diagram showing the calculated evaluation cost for each transport vehicle. [Figure 6] A diagram showing a comparative example of evaluation costs between transport vehicle A and transport vehicle B. [Figure 7] Diagram showing other examples of specific intervals. [Modes for carrying out the invention]

[0010] The following describes an embodiment of the goods transport equipment with reference to the drawings.

[0011] As shown in Figure 1, the goods transport equipment 100 includes a plurality of transport vehicles 1 that move along a predetermined travel path 9 to transport goods W (see Figures 2 and 3), and a control system 2 that causes the transport vehicles 1 to perform transport processing where the source F and destination T of the goods W are specified.

[0012] In this embodiment, the movement path 9 is set so that the direction of movement of the transport vehicle 1 is constant. In other words, the movement path 9 is one-way, and the transport vehicle 1 cannot move in the wrong direction.

[0013] As shown in FIGS. 2 and 3, in the present embodiment, the movement path 9 is set at a position spaced upward from the floor surface. For example, the movement path 9 is configured using a rail 90 provided near the ceiling. The transport vehicle 1 is configured as a so-called ceiling transport vehicle and travels along the rail 90 along the movement path 9.

[0014] There are various articles W handled by the article transport facility 100. In the present embodiment, the article transport facility 100 is used in a semiconductor manufacturing factory. Therefore, a substrate storage container (so-called FOUP: Front Opening Unified Pod) for storing a substrate (such as a wafer or a panel) and a reticle storage container (so-called reticle pod) for storing a reticle are used as the article W. In this case, the transport vehicle 1 transports the article W such as a substrate storage container or a reticle storage container between the respective processes along the movement path 9.

[0015] As shown in FIG. 1, article holding parts 3 that can hold the article W and can transfer the article W between the transport vehicle 1 are arranged at a plurality of locations along the movement path 9.

[0016] As shown in FIG. 2, in the present embodiment, the article holding part 3 includes a load port that is adjacently arranged with respect to a processing device 30 that performs processing on the article W. "Processing on the article W" means processing on the stored object (substrate or reticle) stored in the article W as a storage container. The processing device 30 performs various processes such as thin film formation, photolithography, and etching.

[0017] The transport vehicle 1 receives the article W that has been processed by the processing device 30 from the article holding part 3, or delivers the article W that has not been processed by the processing device 30 to the article holding part 3. The transport vehicle 1 is provided with a gripping part 10 configured to be able to grip the article W, and is configured to transfer the article W with the article holding part 3 by the gripping part 10.

[0018] In the illustrated example, the load port as the article holding part 3 is disposed below the movement path 9 of the carrier vehicle 1. The carrier vehicle 1 transfers the article W with the article holding part 3 by raising and lowering the gripping part 10.

[0019] Also, as shown in FIG. 2, when the article holding part 3 is not disposed directly below the movement path 9 but is displaced horizontally from the movement path 9, the carrier vehicle 1 arranges the gripping part 10 directly above the article holding part 3 by sliding the gripping part 10 horizontally from the bogie body. Thereafter, the carrier vehicle 1 transfers the article W with the article holding part 3 by raising and lowering the gripping part 10.

[0020] Also, due to the structure of the article holding part 3, there may be a restriction on the orientation of the article W disposed in the article holding part 3. In such a case, the carrier vehicle 1 changes the orientation of the article W held by the gripping part 10 by turning the gripping part 10 about the vertical axis. Thereby, the orientation of the article W can be set to an appropriate orientation with respect to the article holding part 3.

[0021] Thus, in the present embodiment, the carrier vehicle 1 includes a slide mechanism for sliding the gripping part 10, a lifting mechanism for raising and lowering the gripping part 10, and a turning mechanism for turning the gripping part 10. When the transfer operation of the article W is performed, the time required for the transfer operation varies depending on whether the gripping part 10 is slid, raised and lowered, or turned. Note that the above transfer operation can also be referred to as a "transfer operation".

[0022] As shown in FIG. 1, at least one of the plurality of article holding parts 3 is a specific holding part 3S capable of transferring the article W from any carrier vehicle 1 located in any of the plurality of specific sections Z in the movement path 9.

[0023] Multiple specific sections Z include a first specific section Z1 and a second specific section Z2 arranged in parallel to each other. "Arranged in parallel to each other" means that the first specific section Z1 and the second specific section Z2 are arranged side by side in a manner other than being continuously aligned along the extending direction of the travel path 9. Therefore, the first specific section Z1 and the second specific section Z2 do not need to be arranged parallel to each other. In this example, the first specific section Z1 and the second specific section Z2 are arranged side by side, left to right.

[0024] In this embodiment, the direction of movement of the transport vehicle 1 permitted in the first specific section Z1 and the direction of movement of the transport vehicle 1 permitted in the second specific section Z2 are set to be different from each other. In the example shown in Figure 1, the only direction of movement of the transport vehicle 1 permitted in the first specific section Z1 is downward in the figure. The only direction of movement of the transport vehicle 1 permitted in the second specific section Z2 is upward in the figure.

[0025] Thus, the first specific section Z1 and the second specific section Z2 are arranged in parallel to each other, and are sections in which the permitted direction of movement of the transport vehicle 1 is different. However, when viewed as the entire travel path 9, the first specific section Z1 and the second specific section Z2 are connected via a connecting section so that the transport vehicle 1 can move. Any path included in the travel path 9 that can connect the first specific section Z1 and the second specific section Z2 can be a connecting section.

[0026] As shown in Figure 3, in this embodiment, the specific holding unit 3S includes a buffer for temporarily holding the article W. In the illustrated example, the buffer, which is the specific holding unit 3S, is located between the first specific section Z1 and the second specific section Z2. Both the transport vehicle 1 in the first specific section Z1 and the transport vehicle 1 in the second specific section Z2 can access this specific holding unit 3S. In other words, the transfer of the article W between either transport vehicle 1 and the specific holding unit 3S is possible.

[0027] As shown in Figure 1, the control system 2 is configured to cause the transport vehicle 1 to perform transport processing. In this example, a higher-level control device that centrally manages multiple transport vehicles 1 constitutes the control system 2. However, in a broader sense, the control system 2 is composed of various control devices within the goods transport equipment 100. For example, a transport vehicle control device (not shown) mounted on each transport vehicle 1 may constitute part or all of the control system 2.

[0028] The control system 2 includes, for example, a processor such as a microcomputer, peripheral circuits such as memory, etc. Each process or function is realized through the cooperation of this hardware and a program executed on the computer's processor.

[0029] The transport process that the control system 2 instructs the transport vehicle 1 to perform specifies the source F where the item W is held and the destination T to which the item W will be transported. At the same time, the control system 2 also specifies the route from the source F to the destination T. The control system 2 can extract multiple routes and select the optimal route (the route that minimizes the total time required from the issuance of the transport command until the completion of the transport process) from among them and specify it to the transport vehicle 1. In executing the transport process, the transport vehicle 1 moves to the source F to receive the item W, and then transports the received item W to the destination T and delivers it. The control system 2 is configured to perform a selection process when selecting the target transport vehicle 1 to perform the transport process from among multiple transport vehicles 1 that do not hold the item W.

[0030] Here, since there are multiple transport vehicles 1 along the movement path 9, each of the multiple transport vehicles 1 becomes a candidate to be selected as the target transport vehicle 1. Then, depending on the current position of each transport vehicle 1, the movement path 9 from each transport vehicle 1 to the transport source F will be different. In other words, there will be multiple movement paths 9 from transport vehicle 1 to the transport source F.

[0031] However, if an item holding unit 3 other than the specific holding unit 3S is the transport source F, the movement path 9 after the transport vehicle 1 receives the item W at the transport source F, i.e., the movement path 9 from the transport source F to the transport destination T, will be the same regardless of which transport vehicle 1 is selected as the target transport vehicle 1. As mentioned above, the movement path 9 is one-way, and a reasonable movement path 9 from the item holding unit 3 (transport source F) to the transport destination T is easily determined uniquely.

[0032] On the other hand, if the specific holding unit 3S is the transport source F, the movement path 9 from the transport source F to the transport destination T will also differ depending on which transport vehicle 1 is selected as the target transport vehicle 1. In other words, since the permitted direction of movement of the transport vehicle 1 differs between the first specific section Z1 and the second specific section Z2, the subsequent movement path 9 to the transport destination T will differ depending on whether the transport vehicle 1 in the first specific section Z1 receives the item W from the specific holding unit 3S (transport source F) or whether the transport vehicle 1 in the second specific section Z2 receives the item W from the specific holding unit 3S (transport source F).

[0033] Based on the above, a selection process is executed to select the target transport vehicle 1 to perform the transport process.

[0034] As shown in Figure 4, the control system 2, through the execution of the selection process, calculates an evaluation cost Cx for each transport vehicle 1 using cost C, which is a value related to the factors that affect the travel time of the transport vehicle 1 and increases as the travel time increases, and selects the target transport vehicle 1 based on the evaluation cost Cx.

[0035] In the selection process when the specific holding unit 3S is designated as the transport source F, the evaluation cost Cx is calculated based on both the receipt cost Cr, which is the cost C corresponding to the travel time from the transport vehicle 1's current position P to the transport source F, and the delivery cost Cg, which is the cost C corresponding to the travel time from the transport vehicle 1's transport source F to the transport destination T. The receipt cost Cr and the delivery cost Cg are each determined by adding a variable cost, calculated considering the possibility of other transport vehicles 1 being present or potentially present on the route, to a base cost calculated assuming no other transport vehicles 1 exist on the route. Furthermore, when the route is defined by one or more links, these base costs and variable costs can also be calculated for each of the links.

[0036] Figure 4 conceptually illustrates the receiving cost Cr and the delivery cost Cg. Figure 4 also shows four transport vehicles A through D as examples, each with a different current position P.

[0037] The receiving cost Cr and the delivery cost Cg are calculated as quantitative values ​​to facilitate comparison between each transport vehicle A to D.

[0038] Factors that affect the travel time of the transport vehicle 1 include, for example, the distance traveled by the transport vehicle 1, the structure of the travel route 9, congestion present in the travel route 9, the time taken for the transfer of goods W, and the number of other transport vehicles 1 present in the travel route 9. The cost C is set to increase as the travel time of the transport vehicle 1 increases due to these factors. In this embodiment, at least one of the following is used to calculate the receiving cost Cr and the delivery cost Cg: a distance cost that increases as the travel distance of the transport vehicle 1 increases; a structure cost that increases as the maximum speed at which the transport vehicle 1 can move decreases according to the structure of the travel route 9 of the transport vehicle 1; a congestion cost that increases as the degree of congestion present in the travel route 9 of the transport vehicle 1 increases; a transfer cost that increases as the time taken for the transport vehicle 1 to transfer goods W between itself and the goods holding unit 3 and between itself and the destination T increases; and an other vehicle cost that increases as the number of other transport vehicles 1 present in the travel route 9 of the transport vehicle 1 increases.

[0039] The distance cost is determined by the length of the distance traveled by the transport vehicle 1. In other words, the distance cost from the current position P to the source F of the transport vehicle 1 is determined by the length of the travel path 9 from the current position P to the source F of the transport vehicle 1. Similarly, the distance cost from the source F to the destination T is determined by the length of the travel path 9 from the source F to the destination T. As the travel distance increases, the travel time for the transport vehicle 1 also increases, and therefore the distance cost becomes relatively larger.

[0040] The structural cost is determined by the structure of the travel path 9. For example, in the straight sections of the travel path 9, the maximum travel speed of the transport vehicle 1 is likely to be set higher, which shortens the travel time of the transport vehicle 1, and therefore the structural cost is relatively lower. On the other hand, in the curved sections of the travel path 9, or in the junction sections where multiple travel paths 9 merge, the maximum travel speed of the transport vehicle 1 is likely to be set lower, which lengthens the travel time of the transport vehicle 1, and therefore the structural cost is relatively higher.

[0041] The congestion cost is determined according to the degree of congestion on the travel route 9. The higher the congestion, the longer the travel time for the transport vehicle 1, and therefore the higher the congestion cost. The congestion degree is set, for example, according to the number of transport vehicles 1 in a predetermined section of the travel route 9, or the speed or time of the transport vehicles 1. Alternatively, the congestion degree may be set based on the length of the congestion. The length of the congestion may be the length of congestion that actually exists on the travel route 9, or it may be the length of congestion that does not currently exist but is predicted to occur in the future.

[0042] The transfer cost is determined by the time it takes for the transport vehicle 1 to transfer the item W. As described above, in this embodiment, the transport vehicle 1 is equipped with a sliding mechanism for sliding the gripping part 10, a lifting mechanism for raising and lowering the gripping part 10, and a swivel mechanism for rotating the gripping part 10. When the item W is transferred, the time required for the transfer operation will differ depending on whether the gripping part 10 is slid and by how much it is slid, whether it is raised and lowered and by how much it is lifted and lowered, and whether it is swiveled and by how much it is swiveled. The longer the time required for the transfer operation, the longer the transport vehicle 1 travels, and therefore the relatively higher the transfer cost.

[0043] The cost of other vehicles is determined by the number of other transport vehicles 1 present along the travel route 9. The presence of other transport vehicles 1 imposes constraints on the operation of the own vehicle. The more other transport vehicles 1 there are, the greater the constraints become, which tends to increase the travel time of the own vehicle, and therefore the relatively higher the cost of other vehicles. Furthermore, the number of other transport vehicles 1 may be the number of other transport vehicles 1 that are actually present, or the number of other transport vehicles 1 that may be present in the future.

[0044] The calculation of the receipt cost Cr and the delivery cost Cg utilizes at least one of the following: distance cost, structural cost, congestion cost, transfer cost, and other vehicle cost. These five costs are considered "element costs," and the receipt cost Cr and delivery cost Cg are calculated, for example, by adding the element costs together, multiplying the element costs together, or a combination thereof. Then, in the selection process when the specific holding unit 3S is the transport source F, the control system 2 calculates the evaluation cost Cx based on both the calculated receipt cost Cr and the delivery cost Cg.

[0045] Furthermore, in the selection process when an item holding unit 3 other than the specific holding unit 3S is designated as the transport source F, the evaluation cost Cx is calculated based on the receipt cost Cr, which is the cost C corresponding to the travel time from the current position P of the transport vehicle 1 to the transport source F. In other words, the delivery cost Cg is not considered. This is because, as mentioned above, the travel route 9 from the transport source F to the transport destination T is the same regardless of which transport vehicle 1 is selected as the target transport vehicle 1.

[0046] Figure 5 shows the evaluation cost Cx for each transport vehicle A to D.

[0047] The control system 2 calculates the evaluation cost Cx for each transport vehicle 1 by executing a selection process, and selects the transport vehicle 1 with the smallest evaluation cost Cx as the target transport vehicle 1. In this embodiment, the evaluation cost Cx is calculated for each transport vehicle 1 by adding the receipt cost Cr and the delivery cost Cg. The control system 2 compares the calculated evaluation costs Cx for each transport vehicle 1 to determine the minimum evaluation cost that results in the smallest evaluation cost Cx, and selects the transport vehicle 1 with the minimum evaluation cost as the target transport vehicle 1.

[0048] In the example shown in Figure 5, the evaluation cost Cx for transport vehicle B is the smallest, so the control system 2 selects transport vehicle B as the target transport vehicle 1.

[0049] Figure 6 illustrates a case where the evaluation cost Cx is calculated using only the distance cost in the selection process when the specific holding unit 3S is the transport source F. Referring to Figure 6, compare the evaluation costs Cx for transport vehicles A and B, which have different current positions P.

[0050] In the example shown in Figure 6, the current position P of transport vehicle A is closer to the source F than the current position P of transport vehicle B. Therefore, the receiving cost Cr is smaller for transport vehicle A than for transport vehicle B. If the selection process only considers the travel path 9 from the current position P of transport vehicle 1 to the source F, then transport vehicle A, with its smaller receiving cost Cr, will be selected as the target transport vehicle 1.

[0051] However, since the specific holding unit 3S is designated as the transport source F, the travel path 9 from the first specific section Z1 to the destination T when transport vehicle A receives the item W is different from the travel path 9 from the second specific section Z2 to the destination T when transport vehicle B receives the item W. Therefore, the delivery costs Cg for both transport vehicle A and transport vehicle B must also be considered.

[0052] In the example shown in Figure 6, the travel path 9 from the second specific section Z2 to the destination T when transport vehicle B receives the item W is shorter than the travel path 9 from the first specific section Z1 to the destination T when transport vehicle A receives the item W. Therefore, the delivery cost Cg is lower for transport vehicle B than for transport vehicle A.

[0053] In this embodiment, the evaluation cost Cx is calculated by adding up the receiving cost Cr and the delivery cost Cg for each transport vehicle 1.

[0054] In the example shown in Figure 6, the evaluation cost Cx (receiving cost Cr + delivery cost Cg) for transport vehicle B is smaller than the evaluation cost Cx (receiving cost Cr + delivery cost Cg) for transport vehicle A. Therefore, the control system 2 selects transport vehicle B as the target transport vehicle 1 in the selection process. This makes it possible to transport the goods W from the source F to the destination T using transport vehicle B in a rational manner.

[0055] [Other Embodiments] Next, other embodiments will be described.

[0056] (1) In the above embodiment, an example was described in which the first specific section Z1 and the second specific section Z2 are arranged side by side. However, the example is not limited to this example, and the first specific section Z1 and the second specific section Z2 may be arranged side by side in any manner other than being continuously aligned along the extending direction of the movement path 9. For example, as shown in Figure 7, in a portion where there are multiple movement paths 9 along the vertical direction, the first specific section Z1 and the second specific section Z2 may be arranged side by side vertically. In this case, both the transport vehicle 1 in the first specific section Z1 and the transport vehicle 1 in the second specific section Z2 can transfer items W to and from the item holding section 3 which is located below both the first specific section Z1 and the second specific section Z2. Therefore, such an item holding section 3 is also called a specific holding section 3S.

[0057] (2) In the above embodiment, an example was described in which the direction of movement of the transport vehicle 1 permitted in the first specific section Z1 and the direction of movement of the transport vehicle 1 permitted in the second specific section Z2 are set to be different directions from each other. However, the invention is not limited to such an example, and these directions of movement may be set to be the same direction from each other.

[0058] (3) In the above embodiment, an example was described in which the evaluation cost Cx is calculated by adding the receipt cost Cr and the delivery cost Cg for each transport vehicle 1. However, the evaluation cost Cx may be calculated, for example, by multiplying the receipt cost Cr and the delivery cost Cg.

[0059] (4) In the above embodiment, an example was described in which the evaluation cost Cx for the transport vehicle 1 is calculated based on three locations: the current position P of the transport vehicle 1, the source of transport F, and the destination T. However, in addition to this, the evaluation cost Cx may also be calculated based on a fourth location that the transport vehicle 1 can reach. An example of a fourth location is a maintenance station where the transport vehicle 1 can perform maintenance and inspections. If the transport vehicle 1 requires repair or charging, after completing the transport process, the transport vehicle 1 will head to the maintenance station (the fourth location). In calculating the evaluation cost Cx, the cost incurred by the transport vehicle 1 to travel to the maintenance station is also taken into consideration.

[0060] (5) In the above embodiment, an example was described in which the movement path 9 is configured using rails 90 provided near the ceiling. However, the invention is not limited to such an example, and the movement path 9 may be configured using rails installed near the floor, and the transport vehicle 1 may be configured to move along the rails. Alternatively, the movement path 9 may be configured using magnetic tape installed on the floor, and the transport vehicle 1 may be configured to move along the magnetic tape.

[0061] (6) The configurations disclosed in the embodiments described above can also be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of this disclosure.

[0062] [Summary of this embodiment] The following is a summary of this embodiment.

[0063] An article transport system comprising: a plurality of transport vehicles that transport articles by moving along a predetermined route; and a control system that causes the transport vehicles to perform transport processing where the source and destination of the articles are specified, Multiple article holding units capable of holding the article and allowing the transport vehicle to receive the article are arranged at multiple locations along the aforementioned movement path. At least one of the multiple article holding units is a specific holding unit that allows the transfer of the article from the transport vehicle located in any of the multiple specific sections of the transport path, The control system is configured to perform a selection process in which, when selecting a target transport vehicle from among a plurality of transport vehicles that do not hold the item, it calculates the evaluation cost of each transport vehicle using a cost that is a value for a factor affecting the travel time of the transport vehicle and increases as the travel time increases, and selects the transport vehicle with the smallest evaluation cost as the target transport vehicle. In the selection process when the specified holding unit is the source of transport, the evaluation cost is calculated based on both the receiving cost, which is the cost corresponding to the travel time from the current position of the transport vehicle to the source of transport, and the delivery cost, which is the cost corresponding to the travel time from the source of transport to the destination of transport.

[0064] According to this configuration, when a specific holding unit is designated as the source of a transport vehicle, the target transport vehicle to perform the transport process can be selected based on both the cost corresponding to the travel time from the transport vehicle's current position to the source and the cost corresponding to the travel time from the transport vehicle's source to the destination. In other words, the situation after the transport vehicle receives the goods at the source can also be used as a criterion for selecting the target transport vehicle. Therefore, this configuration makes it possible to achieve highly rational goods transport.

[0065] In the selection process when an article holding unit other than the specified holding unit is designated as the transport source, it is preferable that the evaluation cost is calculated based on the receiving cost, which is the cost corresponding to the travel time from the current position of the transport vehicle to the transport source.

[0066] For example, if the direction of movement of the transport vehicle along the transport path is restricted to one direction, and an item holding unit other than the specified holding unit is designated as the transport source, the transport path from the transport vehicle receiving the item at the transport source to the destination (the transport path from the transport source to the destination) will be the same regardless of which transport vehicle is involved. In such cases, there is little need to consider the delivery cost when calculating the evaluation cost. With this configuration, in the selection process when an item holding unit other than the specified holding unit is designated as the transport source, the evaluation cost is calculated based on the receiving cost, so the delivery cost can be excluded from the calculation elements, and the computational load on the control system can be reduced.

[0067] The multiple specified sections include a first specified section and a second specified section arranged in parallel with each other. The direction of movement of the transport vehicle permitted in the first specific section and the direction of movement of the transport vehicle permitted in the second specific section are set to be different from each other. Preferably, the first specific section and the second specific section are connected via a connecting section so that the transport vehicle can move between them.

[0068] The travel path to the specific holding unit differs depending on whether the transport vehicle passes through the first specific section or the second specific section, and the travel path from the specific holding unit to the destination is also likely to differ. However, as described above, the evaluation cost, which serves as an indicator for selecting the target transport vehicle, is calculated based on both the receiving cost corresponding to the travel path the transport vehicle takes to reach the specific holding unit and the delivery cost corresponding to the travel path from the specific holding unit to the destination. Therefore, even when a first specific section and a second specific section are provided in the travel path as in this configuration, the control system can select the optimal transport vehicle as the target transport vehicle.

[0069] The calculation of the aforementioned receiving cost and the aforementioned delivery cost includes: The distance cost increases as the travel distance of the transport vehicle increases, The structural cost increases as the movable speed of the transport vehicle decreases, depending on the structure of the transport vehicle's movement path, The congestion cost increases as the degree of congestion in the transport vehicle's travel path increases, The transfer cost increases as the time taken for the transport vehicle to transfer the item between the item holding unit and the destination vehicle increases, The cost of other vehicles increases as the number of other transport vehicles in the transport vehicle's travel path increases, It is preferable that at least one of the following is used.

[0070] This configuration allows for the appropriate determination of various costs based on the various factors affecting the transport vehicle's travel time. Since these costs are used in calculating the receiving cost, delivery cost, and ultimately the evaluation cost, it becomes possible to appropriately select the target transport vehicle. [Industrial applicability]

[0071] The technology relating to this disclosure can be used in an article transport system comprising: a plurality of transport vehicles that transport articles by moving along a predetermined route; and a control system that causes the transport vehicles to perform transport processing where the source and destination of the articles are specified. [Explanation of Symbols]

[0072] 100: Goods handling equipment 1: Transport vehicle 2: Control System 3: Article holding part 3S: Specific holding part 9: Travel Route Cx: Evaluation cost C: Cost Cg: Delivery cost Cr: Cost received F: Source of transport T: Destination P:Current position Z: Specific section Z1: First designated section Z2: Second designated section W:Goods

Claims

1. An article transport system comprising: a plurality of transport vehicles that transport articles by moving along a predetermined route; and a control system that causes the transport vehicles to perform transport processing where the source and destination of the articles are specified, Multiple article holding units capable of holding the article and allowing the transport vehicle to receive the article are arranged at multiple locations along the aforementioned movement path. At least one of the multiple article holding units is a specific holding unit that allows for the transfer of the article from any of the multiple specific sections in the transport path, The control system is configured to perform a selection process in which, when selecting a target transport vehicle from among a plurality of transport vehicles that do not hold the item, it calculates the evaluation cost of each transport vehicle using a cost that is a value for a factor affecting the travel time of the transport vehicle and increases as the travel time increases, and selects the transport vehicle with the smallest evaluation cost as the target transport vehicle. In the selection process where the specified holding unit is the source of transport, and each of the multiple transport vehicles can reach the destination via the specified holding unit from their respective current positions, the evaluation cost is calculated based on both the receiving cost, which is the cost corresponding to the travel time from the current position of the transport vehicle to the source of transport, and the delivery cost, which is the cost corresponding to the travel time from the source of transport to the destination of transport, for an article transporting facility.

2. In the selection process when an article holding unit other than the specified holding unit is designated as the transport source, the evaluation cost is calculated based on the receiving cost, which is the cost corresponding to the travel time from the current position of the transport vehicle to the transport source, as described in claim 1.

3. The multiple specified sections include a first specified section and a second specified section arranged in parallel with each other. The direction of movement of the transport vehicle permitted in the first specific section and the direction of movement of the transport vehicle permitted in the second specific section are set to be different from each other. The article transport equipment according to claim 1 or 2, wherein the first specific section and the second specific section are movably connected via a connecting section to the transport vehicle.

4. The calculation of the aforementioned receiving cost and the aforementioned delivery cost includes: The distance cost increases as the travel distance of the transport vehicle increases, The structural cost increases as the movable speed of the transport vehicle decreases, depending on the structure of the transport vehicle's movement path, The congestion cost increases as the degree of congestion in the transport vehicle's travel path increases, The transfer cost increases as the time taken for the transport vehicle to transfer the item between the item holding unit and the destination vehicle increases, The cost of other vehicles increases as the number of other transport vehicles in the transport vehicle's travel path increases, The article conveying equipment according to claim 1 or 2, wherein at least one of the following is used.

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