Conveyance vehicle system

Abstract

To provide a conveyance vehicle system which can shorten time required for path search without lowering conveyance efficiency.SOLUTION: A conveyance vehicle system 1 according to the present invention has a conveyance vehicle 10 for travel on a route 2 to convey an article, and a conveyance vehicle controller 20 for managing the conveyance vehicle 10. The conveyance vehicle controller 20 has a storage unit 27 for storing a conveyance request for conveying an article from a conveyance origin to a conveyance destination, and a travel direction determination unit 23 for calculating, based on the conveyance origin and the conveyance destination included in the conveyance request, calculating a traffic amount during at least a part of segment of the route 2 to thereby determine a travel direction of the conveyance vehicle 10 in the segment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a transport vehicle system. [Background technology]

[0002] Conventionally, there is known a transport system in which a carriage traveling on a travel path processes a transport request to transport a load from a source to a destination, as described in Patent Document 1. In this system, a transport controller (transport control device) evaluates multiple routes based on the cost based on the passing time of the travel section, and determines the optimal route from the evaluation results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-337623 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional route search method described above has the problem that when conflicts between carts occur along a portion of the route (for example, when a collision occurs in an aisle where passing is difficult), the number of search nodes increases rapidly, increasing the time required for route search. One way to address this problem is to impose restrictions on the travel direction for that portion of the route. However, such restrictions may result in time periods when transport cannot be performed via the shortest distance, leading to reduced transport efficiency.

[0005] The present disclosure describes a guided vehicle system that can reduce the time required for route search without reducing transportation efficiency. [Means for solving the problem]

[0006] [1] A transport vehicle system according to one embodiment of the present disclosure includes a transport vehicle that travels along a predetermined route to transport items, and a controller that manages the transport vehicle. The controller has a storage means that stores a transport request for transporting an item from a source to a destination, and a travel direction determination means that calculates traffic volume in at least a portion of the route based on the source and destination included in the transport request, and determines the travel direction of the transport vehicle in that portion to be either a first direction, a second direction opposite to the first direction, or both directions.

[0007] According to the guided vehicle system of [1], the controller calculates the traffic volume in the section based on the source and destination included in the transportation request, and determines the travel direction. This allows the number of guided vehicles passing through that section to be increased. In addition, determining the travel direction prevents an increase in the number of search nodes. Therefore, the time required for route search can be shortened without reducing transportation efficiency.

[0008] [2] In the guided vehicle system described in [1] above, the controller may determine the driving direction in narrow roads where guided vehicles cannot pass each other. Narrow roads are prone to affecting the number of vehicles passing through because they cannot pass each other. By determining the driving direction at least in narrow roads, the time required to determine the driving direction can be shortened. It is also possible to prevent unnecessary restrictions on the driving direction.

[0009] [3] In the guided vehicle system described in [2] above, when changing the traveling direction in a narrow passage, the controller may change the traveling direction after confirming that there are no guided vehicles in the narrow passage. This control can prevent deadlocks between guided vehicles traveling in opposite directions.

[0010] [4] In the guided vehicle system of [2] or [3] above, before changing the traveling direction in a narrow passage, the controller may perform a tentative route search from a downstream area downstream of the narrow passage to an upstream area upstream of the narrow passage based on the current traveling direction, and if no route exists, change the traveling direction in the narrow passage to either direction. This control ensures that a route is available, thereby preventing situations where a transportation request cannot be fulfilled.

[0011] [5] In the guided vehicle system described in [4] above, the controller searches for a tentative route starting from a route with low traffic volume, and when the traveling direction is changed to bidirectional at a narrow road, it is not necessary to search for a tentative route between the downstream area and the upstream area of ​​the narrow road. According to this control, by making the route with low traffic volume bidirectional, it is possible to prevent transportation failures and suppress a decrease in traffic volume.

[0012] [6] In any one of the guided vehicle systems [1] to [5] above, the controller may include in the traffic volume calculation conditions, in addition to the conditions under which the guided vehicle travels from the origin to the destination, at least one of the conditions under which the guided vehicle travels from a waiting point to the origin, the conditions under which the guided vehicle travels from the destination to the waiting point, and the conditions under which the guided vehicle travels between a plurality of different waiting points. According to this control, the actual traveling state (movement) of each guided vehicle is taken into consideration, so that the traveling direction can be determined more accurately. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to reduce the time required for route search without reducing transport efficiency. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an overall schematic diagram of a guided vehicle system according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram showing the functional configuration of a controller according to an embodiment. [Figure 3] FIG. 3 is a diagram conceptually showing a route in the guided vehicle system. [Figure 4] FIG. 4 is a diagram for explaining an example of an algorithm applied to the calculation of traffic volume. [Figure 5] 5(a), 5(b), and 5(c) are diagrams showing the types of traveling directions (determination results) determined by the controller. [Figure 6] FIG. 6 is a diagram illustrating a state before changing the traveling direction on a narrow road. [Figure 7] FIG. 7 is a diagram illustrating a state after changing the traveling direction on a narrow road. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated description will be omitted.

[0016] First, an overview of a guided vehicle system 1 will be described with reference to Figures 1 and 2. As shown in Figure 1, the guided vehicle system 1 is a transport system that transports articles between multiple processing devices (not shown) arranged in a building of a manufacturing factory for electronic components, etc., and transports articles between the outside and inside of the building. As shown in Figures 1 and 2, the guided vehicle system 1 includes multiple guided vehicles 10 that transport articles, a guided vehicle controller (controller) 20 that controls the multiple guided vehicles 10, and a host controller 5 that issues transport requests to the guided vehicle controller 20. In the guided vehicle system 1, a travel path for the guided vehicle 10 is calculated based on MAPF (Multi-Agent Path Finding) or multi-vehicle control under the control of the guided vehicle controller 20.

[0017] The guided vehicle system 1 has multiple buildings. As shown in Fig. 1, the guided vehicle system 1 includes, for example, a first building BA and a second building BB. The first building BA and the second building BB are located on the same floor and are connected by, for example, two connecting paths, a first narrow passage R1 and a second narrow passage R2. The multiple guided vehicles 10 travel freely in a first area Aa in the first building BA and a second area Ab in the second building BB.

[0018] The first building BA is provided with, for example, one or more (three in the illustrated example) first stations SA. The first building BA is further provided with one or more (two in the illustrated example) charging points 11 and one or more (one in the illustrated example) waiting points 13. The second building BB is provided with, for example, one or more (three in the illustrated example) second stations SB. The second building BB is further provided with one or more (two in the illustrated example) charging points 11 and one or more (one in the illustrated example) waiting points 13. At the first station SA installed in the first building BA, items related to one or more manufacturing processes are transferred. At the second station SB installed in the second building BB, items related to one or more manufacturing processes different from the manufacturing process related to the first station SA are transferred. These manufacturing processes are connected (interrelated) in a predetermined order.

[0019] A plurality of transport vehicles 10 transport items corresponding to each manufacturing process (each manufacturing stage) between stations. A "station" refers to a location where the transport vehicles 10 load and unload. The charging point 11 includes, for example, a charger that charges (supplies power to) the battery of the transport vehicle 10. The waiting point 13 is set at a predetermined position on the floor. The various stations and points described above are merely examples. The number and types of the various stations and points included in the transport vehicle system 1 are not particularly limited. The charging point 11 may also be called a charging station.

[0020] The guided vehicle system 1 may also include other transport devices such as conveyors. The guided vehicle system 1 may also include conveyors or stations related to loading and unloading. All or at least some of the first station SA and the second station SB may have one or more buffers for temporarily storing items. In addition to the above, the guided vehicle system 1 may also include other known configurations that are applied to general guided vehicle systems.

[0021] The guided vehicle 10 is an automated guided vehicle that travels autonomously along a predetermined path 2 on a floor surface. The guided vehicle 10 is, for example, an AGV (Automated Guided Vehicle). The path 2 may include, for example, magnetic tape or magnetic markers provided on the floor surface of a building to form a travel path for the guided vehicle 10. In this case, the guided vehicle 10 travels while detecting magnetic signals output from the magnetic tape or magnetic markers. The guided vehicle 10 may travel while detecting its own position by generating light from a laser or the like and detecting the light reflected by a mirror attached to the wall of the building, or may travel while detecting its own position using information from a GPS or the like. SLAM (Simultaneous Localization and Mapping) technology may be used as a guidance method for the guided vehicle 10.

[0022] The transport vehicle system 1 of this embodiment is equipped with a plurality of transport vehicles 10. Each transport vehicle 10 transports articles between at least a plurality of stations. Each transport vehicle 10 is capable of transporting articles from any station to any other station. Each transport vehicle 10 is capable of transferring (handing over) articles between two different stations. Each of the first station SA and the second station SB may be called a "transfer station."

[0023] When a transport command is assigned from the transport vehicle controller 20, the transport vehicle 10 executes travel control and loading / unloading control to transport an article from either the first station SA or the second station SB, which is the source of the transport command, to another one of the first station SA or the second station SB, which is the destination. The travel control may utilize, for example, the various guidance methods described above. The loading / unloading control involves raising and lowering a lifter possessed by the transport vehicle 10, thereby loading an article from the source station onto the transport vehicle 10 and unloading an article from the transport vehicle 10 to the destination station.

[0024] The guided vehicle controller 20 is a control device that is disposed on the ground and manages multiple guided vehicles 10. The guided vehicle controller 20 is a computer that includes a ROM (Read Only Memory) that stores programs and the like, a RAM (Random Access Memory) that temporarily stores data, a storage medium such as an HDD (Hard Disk Drive), a processor such as a CPU (Central Processing Unit), and a communication circuit such as a wireless LAN. The guided vehicle controller 20 can be configured as software in which a program stored in the ROM is loaded onto the RAM and executed by the CPU. The guided vehicle controller 20 may also be configured as hardware such as an electronic circuit. The guided vehicle controller 20 may be configured as a single device or multiple devices. When configured as multiple devices, these devices are connected via a communication network such as the Internet or an intranet to logically configure a single guided vehicle controller 20.

[0025] The guided vehicle controller 20 is connected to the guided vehicle 10 and the upper controller 5 wirelessly or by wire. The guided vehicle controller 20 receives information from the guided vehicle 10, such as the current position and current speed of the guided vehicle 10. The guided vehicle controller 20 receives a transport request from the upper controller 5 to transport an article from one station to another station. The guided vehicle controller 20 generates a transport command in response to the received transport request and assigns the transport command to the guided vehicle 10.

[0026] The transport command is a control command for transporting an article from the source transfer station in the transport request to the destination transfer station by the transport vehicle 10. The transport command includes information regarding the transfer of the article at the source transfer station, traveling along the route 2 from the source transfer station to the destination transfer station, and the transfer of the article at the destination transfer station.

[0027] As shown in FIG. 2, the guided vehicle controller 20 includes a transport request receiving unit 21, a guided vehicle control unit 22 that controls (or manages) multiple guided vehicles 10, and a memory unit 27 that stores information related to the control. The transport request receiving unit 21 receives a transport request to transport an item from a source (From) to a destination (To), for example, from a higher-level controller 5. In the guided vehicle system 1, multiple transport requests may be generated based on an inbound / outbound plan, a production plan, etc., at the start of system operation for one day (such as in the morning). The memory unit 27 stores, for example, a batch of transport requests for one day. The memory unit 27 is a storage means that stores multiple transport requests.

[0028] Alternatively, in the guided vehicle system 1, multiple transport requests may occur successively even while the system is operating. The transport request receiving unit 21 generates a transport request in response to the multiple received transport requests and stores these multiple transport requests in the memory unit 27. Furthermore, when future transport requests cannot be predicted, the transport request receiving unit 21 and the memory unit 27 may collect and store transport requests in time units of less than one hour in order to grasp the instantaneous wind speed trend at that time. The memory unit 27 may also store information regarding the route 2 and information regarding the status of each guided vehicle 10.

[0029] The guided vehicle control unit 22 further includes a travel direction determination unit (travel direction determination means) 23, an allocation unit 24, and a travel route calculation unit 25. The travel direction determination unit 23 determines the travel direction of the guided vehicle in the section by calculating the traffic volume in at least a part of the section of the route based on the source and destination included in the transport command (transport request). The "section" in the guided vehicle system 1 will be described later. The allocation unit 24 allocates any of the guided vehicles 10 to the generated transport command (transport request). The travel route calculation unit 25 calculates (performs route search) the travel route of the guided vehicle 10 that will perform the transport based on the source and destination included in the transport command (transport request). The travel route calculation unit 25 calculates (performs route search) the travel route by taking into account the travel direction in the section determined by the travel direction determination unit 23. The allocation of the guided vehicles 10 by the allocation unit 24 and the calculation of the travel route by the travel route calculation unit 25 are realized by a known method in the field of MAPF, for example.

[0030] The guided vehicle system 1 of this embodiment is equipped with a configuration for reducing the time required for route search while maintaining a certain level of transport efficiency. The travel direction determination unit 23 determines, for example, the travel direction of guided vehicles 10 in a narrow passageway where they cannot pass each other. The "narrow passageway" in the guided vehicle system 1 may be determined in advance by a designer or the like. The layout of the route 2 in the guided vehicle system 1 can be conceptually explained, for example, as shown in FIG. 3. The route 2 includes multiple nodes N and multiple links L connecting them. When the route is defined in a lattice pattern as shown in the example, four links L are connected to a certain node N, three links L are connected to another certain node N, and two links L are connected to another certain node N. For example, guided vehicles 10 cannot pass each other between the end node N1a on the first area Aa side and the end node N1b on the second area Ab side, which constitute the section corresponding to the first narrow passageway R1. Furthermore, the guided vehicles 10 cannot pass each other between the end node N2a on the first area Aa side and the end node N2b on the second area Ab side, which constitute the section corresponding to the second narrow passage R2. The designers are aware of the above and define the first narrow passage R1 and the second narrow passage R2 as "narrow passages."

[0031] Note that narrow paths can be extracted from route 2 by guided vehicle controller 20, without being limited to being determined by a designer. That is, narrow paths can be extracted automatically in guided vehicle system 1. In this case, narrow paths are extracted through the following four steps. In the first step, guided vehicle controller 20 interprets the layout of route 2 as consisting of possible stopping points (each node N in FIG. 3) and guided vehicle paths (each link L in FIG. 3) connecting each node N (at this stage, the travel direction is bidirectional for all links L (see FIG. 5(c))). Then, in the second step, guided vehicle controller 20 extracts nodes N with a link connection count of two for link L. The "nodes with a link connection count of two" are narrow path node N1c and narrow path node N2c in FIG. 3. Next, in the third step, the guided vehicle controller 20 traces the links L in both directions from the narrow path nodes N1c and N2c, respectively, and identifies the first two nodes N reached, each with a link connection count of three. The guided vehicle controller 20 defines the passage with these two nodes N as its endpoints as a "narrow path." The "end points" here refer to the endpoints N1a, N1b, N2a, and N2b in FIG. 3. If the guided vehicle controller 20 reaches a node N with a link connection count of one, it returns to the second step and searches for another. Then, in the fourth step, the guided vehicle controller 20 returns to the second step and repeats the second and third steps until all nodes N have been searched. Through the above series of search processes, all "narrow paths" included in the route 2 of the guided vehicle system 1 are extracted.

[0032] The travel direction determination unit 23 determines the travel direction of the guided vehicle in the first narrow passage R1 and the second narrow passage R2 by calculating the traffic volume in these first narrow passage R1 and the second narrow passage R2 based on the source and destination included in the transport command (transport request). In this specification, a "narrow passage" refers to at least a partial section of the route 2 selected by the travel direction determination unit 23 (or the guided vehicle controller 20). The travel direction determination unit 23 determines the travel direction in the first narrow passage R1 and the second narrow passage R2 by recalculating the travel direction, for example, when the time period for receiving and shipping goods changes in the guided vehicle system 1 or when batch processing in each manufacturing process ends. Compared to searching for a route for the guided vehicle 10 without any travel direction constraints, the amount of calculations can be reduced by performing a route search after calculating the travel direction from time to time, as in this embodiment.

[0033] First, the calculation of traffic volume will be explained. Information related to transport commands (transport requests) used to calculate traffic volume can be obtained, for example, from inbound / outbound plans and production plans at the start of system operation for the day (such as in the morning), to determine various trends, such as the time periods of requested volume for each scheduled transport request. Here, the "inbound / outbound plan" is information indicating the inbound time period during which transport from the receiving area to the storage area is the main focus, and the shipping time period during which transport from the storage area to the shipping area is the main focus, in a transport system within a logistics center in the distribution industry. Furthermore, the "production plan" is information indicating the expected time and volume of transport between each process in a transport system within a manufacturing factory. As another example, when future transport requests cannot be predicted, transport requests that occurred within a certain period of time in the past (for example, 10 minutes) can be used to calculate traffic volume.

[0034] Hereinafter, the determination of the travel direction by the guided vehicle controller 20 will be illustrated with reference to Fig. 3 to Fig. 5. Fig. 4 is a diagram for explaining an example of an algorithm applied to calculation of traffic volume in the guided vehicle system 1. The algorithm shown in Fig. 4 is called a slime mold algorithm. In this algorithm, the behavior of slime mold is modeled by applying the flow in a water pipe.

[0035] First, assign the numbers 1, 2, 3, ... as identification numbers (subscripts) to each node N shown in Figure 3. At this time, focus on one transport flow, and let s be the node number corresponding to the transport source of that flow, and g be the node number corresponding to the transport destination. Q in the following formula ij , D ij , L ij is the node N i and N j It corresponds to the transportation demand, traffic volume, and aisle length in the aisle between them, and is interpreted as the (i,j) element of the matrix Q, D, L. i is interpreted as element i of column vector p. Note that node N i and N j If are not adjacent, Q ij =D ij =L ij =0. L ij is the path length, so it is a fixed value that is not affected by the time evolution in the calculation, but Q ij and D ij The value of is updated according to the time evolution of the calculation (approaching a reasonable value as a solution). The initial value at calculation step T=0 is i and N j For adjacent i,j, Q ij =0,D ij = 1. In this case, the following equation (1) means solving the simultaneous equations expressed as Ap = b. The diagonal elements of the matrix A are expressed as the following equation (5). j = neighbors is the number of nodes N i The off-diagonal (i,j) elements (i ≠ j) of matrix A are i and N j If there are no adjacent i and N j If adjacent, it is expressed by the following formula (6). The sth element of the column vector b is -Q o and the gth element is +Q o and the other components are 0. However, Q o represents the number of requests generated per unit time for the transport flow of interest.

[0036] From the above, since A and b are expressed as known quantities at calculation step T=0, p can be found by solving the simultaneous equations. Substituting this p into the following equation (3) gives the matrix Q. Substituting this Q into the following equations (2) and (4) gives D at the next step T=1. The above calculations are repeated until the value converges to obtain the converged value D. Note that in the following equation (4), γ=1.5 is used, and repeated calculations of about T=10 steps are required until convergence, which is less than one second for a practical-scale transport system. However, since this is the traffic volume for one transport flow of interest, the above calculations are repeated to obtain the integrated value D for the transport flow traveling from the first area Aa to the second area Ab. ij(A→B) , that is, the traffic volume from the first area Aa to the second area Ab. Similarly, the travel direction determination unit 23 determines the traffic volume D ij(B→A) Calculate.

[0037]

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[0038] The travel direction determination unit 23 determines, for example, the travel direction of the passage (restriction on the travel direction) to be the direction with the greater traffic volume. The travel direction determination unit 23 repeats the above process at regular time intervals, for example, to determine the optimal travel direction at that time.

[0039] 5(a), 5(b), and 5(c) are diagrams showing the types of driving directions (determination results) determined by the controller. For example, when determining the driving direction in a first narrow passage R1, the driving direction determination unit 23 determines the driving direction in the first narrow passage R1 as one of the first direction D1 (see FIG. 5(a)), the second direction D2 opposite to the first direction (see FIG. 5(b)), or the bidirectional direction D3 (see FIG. 5(c)) based on the processing exemplified above. 23 also determines the driving direction for the second narrow passage R2 using a similar method.

[0040] Furthermore, even after determining the driving direction, the driving direction determination unit 23 switches (changes) the driving direction by recalculating the driving direction at each narrow road (first narrow road R1 and second narrow road R2) as appropriate. The following various opportunities are considered as timings for switching the driving direction, for example. (1) When all schedules used to determine the driving direction have been completed (2) When the specified time arrives after calculations are made assuming that the direction of travel will be changed at that time. (3) When the specified processing quantity is reached after calculations are made assuming that the direction of travel will be changed at the specified processing quantity.

[0041] The travel direction is also changed in the same manner as the travel direction determination described above. When changing the travel direction in the first narrow passage R1 and / or the second narrow passage R2, the travel direction determination unit 23 confirms that the guided vehicle 10 is not present in the narrow passage before changing the travel direction. In other words, when changing the travel direction in the first narrow passage R1 and / or the second narrow passage R2, the travel direction determination unit 23 confirms that the guided vehicle 10 has exited the narrow passage before changing the travel direction.

[0042] 6 and 7 show examples of the control of changing the travel direction. As shown in Fig. 6, if the travel direction (passage direction) in the first narrow passage R1 and the second narrow passage R2 is determined individually, for example, if both the first narrow passage R1 and the second narrow passage R2 are determined (restricted) to be the first direction D1, there is a concern that the guided vehicle 10 may not be able to move from the second area Ab to the first area Aa. Here, the travel direction determination unit 23 changes the travel direction in these narrow passages.

[0043] Before changing the driving direction in the first narrow road R1 and the second narrow road R2, the driving direction determination unit 23 performs a tentative route search, for example, from the second area Ab (downstream area) on the downstream side of the narrow road to the first area Aa (upstream area) on the upstream side, based on the current driving direction. If the route search results in no driving route being available, the driving direction determination unit 23 changes the driving direction in the first narrow road R1 to, for example, a bidirectional direction D3, as shown in FIG. 7. In this case, no driving direction restrictions are imposed on the first narrow road R1.

[0044] Furthermore, the driving direction determination unit 23 performs the above-mentioned tentative route search starting from a route with less traffic volume. In the example shown in FIG. 6, the traffic volume in the first narrow road R1 is less than the traffic volume in the second narrow road R2. Therefore, the driving direction determination unit 23 first checks the driving direction for the first narrow road R1. Furthermore, if the driving direction is changed to the bidirectional direction D3 in the first narrow road R1 (a certain narrow road), the driving direction determination unit 23 does not perform a tentative route search between the second area Ab and the first area Aa (i.e., between the same areas where the above-mentioned tentative route search was performed).

[0045] According to the guided vehicle system 1 of this embodiment, the guided vehicle controller 20 (specifically, the travel direction determination unit 23) calculates the traffic volume in the first narrow passage R1 and the second narrow passage R2 based on the source and destination included in the transportation request, and determines the travel direction. At this time, the travel direction in the first narrow passage R1 and the second narrow passage R2 determined by the travel direction determination unit 23 is taken into account. The travel direction is determined to be either the first direction D1, the second direction D2, or both directions D3. This makes it possible to increase the number of guided vehicles 10 passing through the section. Furthermore, determining the travel direction prevents an increase in the number of search nodes. Therefore, it is possible to shorten the time required for route search without reducing transportation efficiency.

[0046] When the timing when the traffic volume fluctuates significantly is adopted as the timing for determining or recalculating the travel direction, the number of guided vehicles 10 that are adversely affected when the travel direction is changed can be reduced.

[0047] The guided vehicle controller 20 determines the traveling direction at least in narrow roads where the guided vehicles 10 cannot pass each other. Narrow roads such as the first narrow road R1 and the second narrow road R2 are likely to affect the number of vehicles passing through because they do not allow the guided vehicles 10 to pass each other. By determining the traveling direction at least in these narrow roads, the time required to determine the traveling direction can be reduced.

[0048] When changing the traveling direction in the narrow passage, the guided vehicle controller 20 changes the traveling direction after confirming that no guided vehicles are present in the narrow passage to be changed. This control makes it possible to prevent deadlocks between guided vehicles 10 traveling in opposite directions.

[0049] Before changing the travel direction in the narrow passage, the guided vehicle controller 20 performs a tentative route search from the downstream area to the upstream area of ​​the narrow passage based on the current travel direction, and if no travel route exists, changes the travel direction in the narrow passage to either direction (see Figure 7). This control ensures that a travel route is available, preventing situations where a transportation request cannot be fulfilled. In other words, the travel direction guarantees that any From-To within the area can always be traveled. This eliminates the need for frequent switching between the conventional combined inbound / outbound mode and a dedicated mode, enabling stable travel of the guided vehicle.

[0050] The guided vehicle controller 20 searches for a tentative route starting from a route with low traffic volume, and when the traveling direction is changed to two-way at a narrow road (see the first narrow road R1 in FIG. 7), the guided vehicle controller 20 does not search for a tentative route between the same areas of the narrow road. According to this control, by making the route with low traffic volume two-way, it is possible to prevent a situation where transportation is impossible and suppress a decrease in traffic volume.

[0051] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above embodiments. For example, the travel direction determination unit 23 (the guided vehicle controller 20) may include, in addition to the condition for the guided vehicle 10 to travel from the origin to the destination, at least one of the following conditions for calculating traffic volume: a condition for the guided vehicle 10 to travel from a waiting point 13 (see FIG. 1 ) to the origin, a condition for the guided vehicle 10 to travel from the destination to the waiting point 13, and a condition for the guided vehicle 10 to travel between multiple different waiting points 13 (when multiple waiting points 13 are in the same area). Furthermore, instead of the waiting point 13, a charging point 11 may be considered. That is, the travel direction determination unit 23 (the guided vehicle controller 20) may include, in addition to the condition for the guided vehicle 10 to travel from the origin to the destination, at least one of the following conditions for calculating traffic volume: a condition for the guided vehicle 10 to travel from the charging point 11 (see FIG. 1 ) to the origin, a condition for the guided vehicle 10 to travel from the destination to the charging point 11, and a condition for the guided vehicle 10 to travel from the waiting point 13 to the charging point 11. According to this control, the actual traveling state (movement) of each transport vehicle is taken into consideration, so that the traveling direction can be determined more accurately.

[0052] More specifically, the condition for the guided vehicle 10 to travel from the waiting point 13 (see FIG. 1 ) to the source of the transport is useful from the viewpoint of shortening the time from the time when the transport request is assigned (not the time when the cargo is loaded) to the time when the cargo is unloaded. The condition for the guided vehicle 10 to travel from the destination of the transport to the waiting point 13 is useful from the viewpoint of allowing the guided vehicle 10 to return to the waiting point quickly and respond quickly to the next request. The condition for the guided vehicle 10 to travel between multiple different waiting points 13 occurs, for example, when a waiting guided vehicle 10 is forced to leave (for example, to give up a limited number of charging points to another vehicle). The longer a guided vehicle 10 unrelated to the fulfillment of a request moves around in the travel area of ​​another vehicle, the greater the risk of interfering with the travel of the guided vehicle 10 currently fulfilling the request, which may hinder the transport. Therefore, the condition for the guided vehicle 10 to travel between multiple different waiting points 13 is useful from the viewpoint of reducing the risk of interfering with the travel of the guided vehicle 10 currently fulfilling the request. Taking these conditions into consideration is optional in the transport vehicle system 1 of this embodiment (that is, any of them can be omitted), but is useful from the perspective of more reliably achieving the transport purpose.

[0053] Inaccuracy in the travel direction can lead to, for example, waiting for passing vehicles or detours, which reduces the number of transport requests that can be executed. In other words, transport processing capacity decreases. Therefore, accurate determination of the travel direction by the travel direction determination unit 23 ensures (or improves) transport processing capacity.

[0054] The travel direction determination unit 23 (transportation vehicle controller 20) is not limited to determining the travel direction only on narrow roads, but may also determine the travel direction on general travel roads other than narrow roads. For example, in the example route shown in FIG. 3, for many nodes N, the transport vehicle 10 can move in four directions on the floor surface. When determining the travel direction on the travel road (part of a section), the travel direction determination unit 23 first restricts the possible movement directions on the travel road to only two directions. The travel direction determination unit 23 determines the travel direction based on the two directions after the restriction.

[0055] In addition, when determining the driving direction, a process may be performed in which both lanes are set to the same direction for a two-lane passageway that allows vehicles to pass each other. The driving direction may be changed (switched) without performing a tentative route search.

[0056] If it is confirmed that no deadlock will occur, switching control for changing the traveling direction may be performed even when the guided vehicle 10 has not yet exited a narrow passage (such as the first narrow passage R1).

[0057] The traffic volume calculation is not limited to the slime mold algorithm, but may be performed using other methods, such as algorithms that solve maximum flow problems, such as the augmented path method or linear programming problems. Other methods may also be used to calculate the direction in which traffic volume is more prevalent for each path.

[0058] The guided vehicle system 1 may include only one guided vehicle 10. The number of guided vehicles 10 included in the guided vehicle system 1 is not particularly limited.

[0059] The transport vehicle 10 is not particularly limited to an AGV, and may be, for example, an overhead traveling vehicle, a tracked vehicle, etc. The transport vehicle 10 may also be a mobile body that has a lifting function and moves in a three-dimensional space, or a drone that can move freely in a three-dimensional space. [Explanation of symbols]

[0060] 1...transport vehicle system, 2...route, 10...transport vehicle, 20...transport vehicle controller (controller), 21...transport request receiving unit, 22...transport vehicle control unit, 23...travel direction determination unit (travel direction determination means), 24...allocation unit, 25...travel path calculation unit, 27...memory unit (memory means), Aa...first area, Ab...second area, R1...first narrow path (narrow path), R2...second narrow path (narrow path).

Claims

1. a transport vehicle that travels along a predetermined route to transport an article; a controller that manages the transport vehicle, The controller a storage means for storing a transport request for transporting the item from a transport source to a transport destination; and a travel direction determination means for determining the travel direction of the transport vehicle in at least a section of the route to be either a first direction, a second direction opposite to the first direction, or both directions, by calculating the traffic volume in at least a section of the route based on the transport source and the transport destination included in the transport request.

2. The guided vehicle system according to claim 1 , wherein the controller determines a traveling direction of the guided vehicles on a narrow road where the guided vehicles cannot pass each other.

3. The guided vehicle system according to claim 2 , wherein the controller, when changing the traveling direction in the narrow passage, changes the traveling direction after confirming that the guided vehicle is not present in the narrow passage.

4. 3. The guided vehicle system according to claim 2, wherein, before changing the traveling direction in the narrow passage, the controller performs a tentative route search from a downstream area downstream of the narrow passage to an upstream area upstream of the narrow passage based on the current traveling direction, and if no traveling route exists, changes the traveling direction in the narrow passage to both directions.

5. 5. The guided vehicle system according to claim 4, wherein the controller performs the tentative route search starting from the route with the least amount of traffic, and when the traveling direction is changed to both directions at a narrow road, the controller does not perform the tentative route search between the downstream area and the upstream area of ​​the narrow road.

6. The transport vehicle system according to any one of claims 1 to 5, wherein the controller includes in the traffic volume calculation conditions, in addition to the conditions for the transport vehicle to travel from the source to the destination, at least one of the conditions for the transport vehicle to travel from a waiting point to the source, the conditions for the transport vehicle to travel from the destination to a waiting point, and the conditions for the transport vehicle to travel between a plurality of different waiting points.

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