Mobile object management device, management method, and management program

Abstract

To provide a management device, a management method, and a management program for a mobile object that can efficiently rearrange shelves.SOLUTION: A management device for a mobile object according to one aspect includes a management unit. The management unit calculates a score based on a transport frequency for each workstation on each shelf located within a facility and a distance between each shelf and the workstation. The management unit determines a rearrangement position of each shelf based on the score and a current position of each shelf.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments relate to a management device, a management method, and a management program for a mobile object. [Background technology]

[0002] As automation in logistics sites advances, the introduction of mobile objects such as automated guided vehicles (AGVs) is progressing to unmanned and streamline cargo transportation. These types of mobile objects transport cargo according to predetermined tasks. In recent years, shelf transport systems have also become known in which the mobile object transports cargo along with the shelves on which the cargo is stored. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6117368 Summary of the Invention [Problem to be solved by the invention]

[0004] In shelf transport systems that use mobile vehicles such as AGVs, there is a desire to place frequently used shelves close by and infrequently used shelves farther away in order to reduce shelf transport time and improve efficiency.However, if the location of shelves to be relocated is determined simply based on frequency of use, the distance that the mobile vehicle must travel for the relocation will be long, which could actually reduce efficiency.

[0005] The embodiments provide a mobile object management device, a management method, and a management program that enable efficient rearrangement of shelves. [Means for solving the problem]

[0006] In one embodiment, the mobile object management device includes a management unit that calculates a score based on the frequency of transport for each workstation of each shelf located within a facility and the distance between each shelf and the workstation. The management unit determines a relocation position for each shelf based on the score and the current position of each shelf. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram of a mobile object management device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of map data representing a travel area stored in the travel area DB. [Figure 3] FIG. 3 is a diagram illustrating an example of node information stored in the node DB. [Figure 4] FIG. 4 is a diagram illustrating an example of link information stored in the link DB. [Figure 5] FIG. 5 is a flowchart showing the operation of the management device. [Figure 6] FIG. 6 is a diagram showing an example of the results of acquiring the transportation frequency. [Figure 7] FIG. 7 is a diagram showing an example of the distance obtained. [Figure 8] FIG. 8 is a diagram showing an example of the calculation result of the score. [Figure 9] FIG. 9 is a diagram illustrating an example of node IDs selected for each pod ID. [Figure 10] FIG. 10 is a conceptual diagram for explaining the basic idea of the method for determining the relocation position. [Figure 11] FIG. 11 is a conceptual diagram of the change of the rearrangement position. [Figure 12] FIG. 12 is a diagram showing an example of a circular arrangement. [Figure 13] FIG. 13 is a diagram showing an example of sequential transport in the case of a circular arrangement. [Figure 14] FIG. 14 is a conceptual diagram of a method for determining a rearrangement position when workstations are divided into a dedicated receiving workstation and a dedicated retrieval workstation. [Figure 15] FIG. 15 is a conceptual diagram of a method for determining the rearrangement position of shelves in the case of dense arrangement. [Figure 16] FIG. 16 is a conceptual diagram of a method for determining the rearrangement position of shelves in the case of dense arrangement. [Figure 17] FIG. 17 is a conceptual diagram of a method for determining a rearrangement position in consideration of the improvement rate of transport efficiency. [Figure 18] FIG. 18 illustrates a hardware configuration of an example of a management device. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a block diagram of a mobile object management device according to an embodiment. The management device 100 is a computer that manages the operation of N (N is a natural number) mobile objects m1, m2, ..., mN. The mobile objects m1-mN are autonomously movable objects such as AGVs, picking robots, autonomous mobile robots, and self-driving vehicles, and operate based on control commands generated by the management device 100. The mobile objects m1-mN move within a facility, such as a factory or warehouse. As an example, the mobile objects m1-mN are equipped with a battery and can move within a travel area within the facility using power from the battery. The mobile objects m1-mN may be configured to transport empty shelves to a workstation (WS) and store the received packages on the shelves at the workstation before moving within the facility. The mobile objects m1-mN may also be configured to autonomously store and retrieve packages from and to the shelves. The storing and retrieval of packages may be performed manually.

[0009] The management device 100 includes a management unit 11, an operation plan generation unit 12, an operation control unit 13, a mobile object management unit 14, and a communication unit 15. The management device 100 may also include a travel area database (DB) 21, a node DB 22, a link DB 23, a mobile object DB 24, a task DB 25, and an operation plan DB 26. The travel area DB 21, the node DB 22, the link DB 23, the mobile object DB 24, the task DB 25, and the operation plan DB 26 may be databases stored in storage separate from the management device 100.

[0010] The travel area DB21 is a database that stores information about travel areas. The information about travel areas includes map data of facilities, such as factories and warehouses, that serve as travel areas for the mobile object. The travel areas have coordinate information. The positions of workstations, shelves, etc. within the facilities and the positions of obstacles temporarily placed within the facilities are associated with coordinates set in the travel area. Here, the map data may be data defined in advance as drawings such as CAD (Computer Aided Design). Alternatively, if the mobile object has a function for creating an environmental map using a self-location detection function, the map data may be data of the environmental map created by that function.

[0011] Fig. 2 shows an example of map data representing a travel area stored in the travel area DB 21. Fig. 2 shows an example in which two workstations WSa and WSb and 33 shelves S are arranged in the travel area. The area other than the workstations WSa and Wsb and the shelves S is an aisle. Mobile objects m1-mN can travel along the aisle.

[0012] At workstation WSa and workstation WSb, goods are stored in or removed from shelf S. At workstation WSa, goods are stored in or removed from shelf S in the order of a1, a2, ..., a8. Similarly, at workstation WSb, goods are stored in or removed from shelf S in the order of b1, b2, ..., b8. Also, goods can be stored in each shelf S. Here, the symbols attached to the shelves S in Figure 2 are node IDs that indicate the position of each shelf S.

[0013] The node DB22 and link DB23 are databases that store information about the travel path network. The travel path network is the travel path of a moving object represented by a network structure, which is set in correspondence with a travel area. The travel path network is composed of nodes and links. A node represents the position of the moving object's movement target, and is associated with the coordinates of the travel area. A link represents the connection between nodes.

[0014] 3 shows an example of node information stored in the node DB 22. The node information includes information on a node ID, an X coordinate, and a Y coordinate. The node ID is an ID that is uniquely assigned to each node to identify each node. The X coordinate is the X coordinate of the position on the map data of the node with the corresponding node ID. The Y coordinate is the Y coordinate of the position on the map data of the node with the corresponding node ID.

[0015] FIG. 4 shows an example of link information stored in the link DB 23. The link information includes a link ID, a first node ID, a second node ID, and information on node directionality. The link ID is an ID uniquely assigned to each link to identify each link. The first node ID is the node ID of the node that is the source of the link with the corresponding link ID. The second node ID is the node ID of the node that is the destination of the link with the corresponding link ID. The node directionality indicates whether movement between nodes is bidirectional or limited to one direction. If it is bidirectional, a mobile object can travel from the source node to the destination node, and from the destination node to the source node. On the other hand, if it is unidirectional, a mobile object can only travel from the source node to the destination node.

[0016] The mobile object DB 24 is a database that stores information about each of the mobile objects m1-mN. The mobile object information includes real-time location information. This location information includes, for example, the location of the mobile object's waiting area. The mobile object's location can be obtained, for example, from data received from the mobile object at regular intervals. Alternatively, the mobile object's location can be obtained from a sensor installed in the travel area. In this case, the sensor is installed, for example, at the location of each node, and when it detects that the mobile object has passed through the corresponding node, it notifies the management device 100 of this fact. The mobile object information stored in the mobile object DB 24 may also include information other than location. For example, the mobile object information may include the remaining battery charge. Furthermore, if the mobile object is configured to transport cargo, the mobile object information may include information indicating whether or not the mobile object is carrying cargo, and if so, information on the type and number of cargo being transported. Furthermore, the mobile object information may include information related to the specifications of each mobile object. The mobile object's specification information may include, for example, standard speed, maximum speed, minimum speed, size, and permitted driving direction. Furthermore, if the mobile object is configured to be able to store and retrieve cargo, the information about the mobile object may include information such as the time required for these operations.

[0017] The task DB 25 is a database that stores task information. The task information is information that represents a task assigned to a mobile object. The task can be input by an operator of the management device 100. The task information includes information on a task ID, a starting point, and an arrival point. The task ID is an ID assigned to each task. The starting point is the node ID of the starting point of the mobile object. If the mobile object to which the task is assigned is not at the starting point at the start of task execution, the mobile object is controlled to travel to the starting point. The arrival point is the node ID of the arrival point of the mobile object, such as a workstation or shelf. In addition to the starting point and the arrival point, the task information may also include information on waypoints. The waypoints are node IDs of points that must be passed through when executing the task. Furthermore, depending on the configuration of the mobile object, the task information may also include information on the starting point, the arrival point, and the content of work to be performed at points between the starting point and the arrival point, such as storing and retrieving cargo.

[0018] The operation plan DB 26 is a database that stores information about the operation plan generated by the operation plan generation unit 12. The operation plan is information about a plan on how to operate a mobile object to execute a task. The operation plan information includes information about an operation plan ID, a travel route, and time. The operation plan ID is an ID assigned to each operation plan. The travel route is the node ID of each point that the mobile object passes through in the corresponding operation plan. The time is the scheduled time that the mobile object will pass each point.

[0019] The management unit 11 manages the operations of the operation plan generation unit 12, the operation control unit 13, the mobile object management unit 14, and the communication unit 15. For example, the management unit 11 instructs the operation plan generation unit 12 to generate an operation plan. Then, the management unit 11 acquires the operation plan generated by the operation plan generation unit 12 from the operation plan DB 26, and instructs the operation control unit 13 to control the operations of the mobile objects m1-mN based on the operation plan.

[0020] The operation plan generation unit 12 generates an operation plan for each of the moving bodies m1-mN based on information about the traveling areas stored in the traveling area DB 21, the node DB 22, and the link DB 23, information about the moving bodies m1-mN stored in the moving body DB 24, and information about the tasks stored in the task DB 25. The operation plan generation unit 12 then stores the generated operation plan in the operation plan DB 26. Any method may be used to generate an operation plan. For example, when operation plans for multiple moving bodies are generated simultaneously, the operation plan for each moving body may be generated so as to minimize the total travel distance of each moving body as long as no collisions or the like occur between the multiple moving bodies.

[0021] The operation control unit 13 acquires an operation plan for each mobile object from the operation plan DB 26 based on instructions from the management unit 11, and generates control commands for each mobile object based on the acquired operation plan. The control commands include commands to travel to the nodes of each destination point registered in the operation plan. The commands to travel may include information such as a node ID and speed, for example. When the initial position of the mobile object is not the starting point, the command to travel may include a command to travel to the node of the starting point of the mobile object. Furthermore, when the mobile object is configured to be able to store and retrieve packages, the control command may include a command to perform work at the coordinates or node of the destination of travel. The command to perform work includes, for example, information on the content of the work. Furthermore, the control command may include a command to rearrange the shelf S. The command to rearrange the shelf S includes a command to travel to the node where the source shelf S is located, a command to receive the source shelf S, a command to travel to the node where the relocation destination is located after receiving the shelf S, and a command to rearrange the shelf S at the destination.

[0022] The mobile object management unit 14 manages the status of each mobile object. For example, the mobile object management unit 14 acquires the current positions detected by the sensors of the mobile objects m1-mN via the communication unit 15, and updates the current positions of each mobile object stored in the mobile object DB 24 based on the acquired current positions. Also, for example, the mobile object management unit 14 acquires the remaining battery power of each mobile object m1-mN via the communication unit 15, and updates the remaining battery power of each mobile object stored in the mobile object DB 24 based on the acquired remaining battery power.

[0023] The communication unit 15 communicates between the management device 100 and the mobile entities m1-mN. The communication unit 15 communicates between the management device 100 and the mobile entities m1-mN, for example, wirelessly.

[0024] Next, a description will be given of the operation of the management device 100. Fig. 5 is a flowchart showing the operation of the management device 100. The operation of Fig. 5 is performed when there is at least one moving object among the moving objects m1-mN to which no task has been assigned.

[0025] In step S1, the management unit 11 of the management device 100 acquires the transport frequency of each shelf S based on the past operation plans stored in the operation plan DB 26. The transport frequency of each shelf S corresponds to the frequency of use of the shelf S and is counted once each time the shelf S is transported to a workstation. When there are multiple workstations as in the embodiment, the transport frequency is counted for each workstation. For example, when an operation plan in which the starting point is the node ID of one of the shelves S and the arrival point is the node ID of workstation WSa is stored in the operation plan DB 26, the transport frequency for workstation WSa of that shelf S is counted once. Here, the acquired transport frequency may be the transport frequency for a specified past period, such as one day, one month, or one year. Furthermore, the acquired transport frequency is not limited to the past transport frequency, but may also be the future transport frequency counted based on order information that determines task allocation.

[0026] FIG. 6 shows an example of the results of acquiring the transport frequency. The example of the results of acquiring the transport frequency includes a pod ID, a transport frequency to the workstation WSa, and a transport frequency to the workstation WSb. A pod ID is an ID that is uniquely assigned to each shelf S. For example, FIG. 2 shows 33 shelves S. In this case, one of the 33 pod IDs is assigned to each shelf S. Here, the pod ID does not change even if the position of the shelf S changes due to rearrangement. The transport frequency to the workstation WSa is the frequency at which the shelf S with the corresponding pod ID is transported to the workstation WSa. The transport frequency to the workstation WSb is the frequency at which the shelf S with the corresponding pod ID is transported to the workstation WSb.

[0027] In the following explanation, it is assumed that pod IDs are numbers from 1 to 33 assigned in raster order from top left to bottom right in the state of Figure 2. In this case, pod ID_1 is assigned to the shelf S located at node ID_A1, and pod ID_2 is assigned to the shelf S located at node ID_A2. Similarly, pod ID_9 is assigned to the shelf S located at node ID_A9, pod ID_10 is assigned to the shelf S located at node ID_C1, and pod ID_33 is assigned to the shelf S located at node ID_F9.

[0028] In step S2, the management unit 11 acquires the distance between the node where each shelf S is located and the node where workstation Wsa is located, and the distance between the node where each shelf S is located and the node where workstation Wsb is located. The distance may be the Manhattan distance between the node of each shelf S and the node of each workstation. Furthermore, when calculating the Manhattan distance, a representative node is used for the node of workstation WSa and the node of workstation WSb. The representative node is any node where workstation WSa or workstation WSb is located. For example, the representative node may be the node where first inventory or inventory is performed. In this case, the representative node of workstation WSa in FIG. 2 is the node with node ID_I2 (point a1 in FIG. 2). Furthermore, for example, the representative node of workstation WSb in FIG. 2 is the node with node ID_I8 (point b1 in FIG. 2).

[0029] FIG. 7 shows an example of distance acquisition results. The example of distance acquisition results includes the node ID, the distance to workstation WSa, and the distance to workstation WSb. The node ID is the node ID of the node where each shelf S is located. The distance to workstation WSa is the Manhattan distance from the node with the corresponding node ID to the representative node of workstation WSa. The distance to workstation WSb is the Manhattan distance from the node with the corresponding node ID to the representative node of workstation WSb.

[0030] In step S3, the management unit 11 selects the pod ID of one shelf S as a target for calculating the score. The pod ID is selected in descending order of the frequency of transportation among the shelves S to which a relocation destination has not been assigned.

[0031] In step S4, the management unit 11 calculates a score for the selected shelf S. The score s can be calculated according to the following formula (1), for example, when the transport frequency of the shelf S of the pod ID selected in step S3 to the workstation WSa is fa, the transport frequency of the shelf S of the pod ID selected in step S3 to the workstation WSb is fb, the distance of the node of each node ID to the workstation WSa is da, and the distance of the node of each node ID to the workstation WSb is db. s = (fa × da) + (fb × db) (1) Here, equation (1) is the calculation of the score when there are two workstations. However, equation (1) can be expanded to cases where there are three or more workstations. For example, when there are three workstations, a third term is added to equation (1), which is the product of the frequency of delivery to the third workstation of shelf S of the pod ID selected in step S3 and the distance to the third workstation of the node of each node ID. The same applies when there are four or more workstations.

[0032] FIG. 8 shows an example of a score calculation result. The example calculation result includes a pod ID, a node ID, and a score. The pod ID is the pod ID selected in step S3. In FIG. 8, pod ID_4 is selected. The node ID is the node ID corresponding to each distance obtained in step S2. The score is the score calculated for the shelf S of the corresponding pod ID.

[0033] In step S5, the management unit 11 selects the node ID with the smallest score among the calculated scores as a candidate for the rearrangement position of the shelf S of the corresponding node ID. If there are multiple node IDs with the smallest score, the management unit 11 selects all of the corresponding node IDs. In the example of Fig. 8, the management unit 11 selects node ID_F1 and node ID_F3.

[0034] In step S6, the management unit 11 determines whether to end the score calculation, that is, whether the selection of all pod IDs has been completed. If it is determined in step S6 that the score calculation is not to end, the process returns to step S3. If it is determined in step S6 that the score calculation is to end, the process proceeds to step S7.

[0035] In step S7, the management unit 11 determines the final rearrangement position of the shelf S based on the candidates for the rearrangement position of each shelf S. The method for determining the rearrangement position of the shelf S will be explained in detail later.

[0036] In step S8, the operation plan generation unit 12 generates an operation plan for a mobile object to which no task is assigned, for rearranging the shelf S. The operation plan in step S8 includes an operation plan for moving the mobile object to the node where the shelf to be rearranged is located, and an operation plan for moving the mobile object holding the shelf to the rearrangement position.

[0037] In step S9, the management unit 11 of the management device 100 acquires from the operation plan DB 26 the operation plan for each moving object to be rearranged on the shelf S, which has been generated by the operation plan generation unit 12. Then, the management unit 11 starts controlling the operation of each moving object by the operation control unit 13 in accordance with the acquired operation plan. The operation control unit 13 generates control commands for each moving object based on the operation plan. Then, the operation control unit 13 controls the operation of the moving object by transmitting the control commands to the moving object using the communication unit 15. This completes the rearrangement of the shelf S.

[0038] Next, a method for determining the rearrangement position of shelf S will be described. The rearrangement position can be determined in descending order of the score s, or in the case of formula (1), in ascending order of the value of score s. In the following, it is assumed that the node ID with the smallest score for each pod ID is selected, for example, as shown in FIG. 9.

[0039] First, the basic concept of the method for determining the relocation position will be explained using Fig. 10. Basically, the node ID of the final relocation position is determined to be the node ID with the shortest travel distance from the current position of shelf S of the corresponding pod ID, among the node IDs of the candidate relocation destinations that have not been assigned as the final relocation destination.

[0040] For example, in FIG. 9, the node IDs of the candidates for the rearrangement position for shelf S of pod ID_4 are node ID_F1 and node ID_F3. Furthermore, the Manhattan distance between the node with node ID_F4, which is the current position of shelf S of pod ID_4, and the node with node ID_F1 and the node with node ID_F3 is both 8. Therefore, the management unit 11 determines the node ID of the final rearrangement position for shelf S of pod ID_4 to be either node ID_F1 or node ID_F3. For example, the management unit 11 randomly determines the node ID of the final rearrangement position from node ID_F1 or node ID_F3.

[0041] Furthermore, the node IDs of the candidate rearrangement positions for shelf S of pod ID_5 are node ID_F3, F4, F6, and F7. Furthermore, the Manhattan distances between the node with node ID_A5, which is the current position of shelf S of pod ID_5, and the nodes with node ID_F3, node ID_F4, node ID_F6, and node ID_F7 are 8, 6, 6, and 8. Therefore, the management unit 11 determines the node ID of the rearrangement position for shelf S of pod ID_5 to be either node ID_F4 or node ID_F6. For example, the management unit 11 randomly determines the node ID of the final rearrangement position from node ID_F4 or node ID_F6. Here, if the management unit 11 has determined the node ID of the rearrangement position for shelf S of pod ID_4 to be node ID_F3, it may exclude node ID_F3 from the candidate rearrangement positions.

[0042] Furthermore, the node IDs of the candidate relocation destinations for shelf S of pod ID_6 are node ID_F7 and node ID_F9. Also, the Manhattan distance between node ID_A6, which is the current location of shelf S of pod ID_6, and nodes ID_F7 and ID_F9, is both 8. Therefore, the management unit 11 determines the node ID of the relocation location for shelf S of pod ID_6 to be either node ID_F7 or node ID_F9. For example, the management unit 11 randomly determines the node ID of the final relocation location from node ID_F7 or node ID_F9. Here, if the management unit 11 has determined node ID_F7 as the node ID of the relocation location for shelf S of pod ID_5, the management unit 11 may exclude node ID_F7 from the candidate relocation locations.

[0043] 10 shows an example in which the management unit 11 determines the node ID of the rearrangement position of shelf S of pod ID_4 to be node ID_F1 as shown by arrow R11, determines the node ID of the rearrangement position of shelf S of pod ID_5 to be node ID_F4 as shown by arrow R12, and determines the node ID of the rearrangement position of shelf S of pod ID_6 to be node ID_F9 as shown by arrow R13. Note that the workstations Wsa and Wsb in FIG. 10 are illustrated with arrows indicating the order of entry or exit to indicate the representative node.

[0044] As is clear from equation (1), the score s tends to decrease as the distance multiplied by the greater of the transfer frequencies fa and fb decreases. In other words, the score s of a shelf S of a pod ID with a high transfer frequency fa, i.e., a high transfer frequency to workstation WSa, decreases as the node ID has a shorter distance da to workstation WSa. This means that the relocation position of a shelf S of a pod ID with a high transfer frequency to workstation WSa is likely to be determined near workstation WSa. Similarly, the score s of a shelf S of a pod ID with a high transfer frequency fb, i.e., a high transfer frequency to workstation WSb, decreases as the node ID has a shorter distance db to workstation WSb. This means that the relocation position of a shelf S of a pod ID with a high transfer frequency to workstation WSb is likely to be determined near workstation WSb.

[0045] For example, 100% of the destinations of the shelves S of pod ID_4 currently located at node ID_A4 are workstation WSa indicated by arrow ta1. Therefore, the relocation destination of the shelves S of pod ID_4 can be determined to be a node with a node ID close to workstation WSa. Furthermore, 50% of the destinations of the shelves S of pod ID_5 currently located at node ID_A5 are workstation WSa indicated by arrow ta2, and the remaining 50% are workstation WSb indicated by arrow tb1. In this case, the relocation destination of the shelves S of pod ID_5 can be determined to be a node with a node ID approximately equidistant from both workstation WSa and workstation WSb. Furthermore, 100% of the destinations of the shelves S of pod ID_6 currently located at node ID_A6 are workstation WSb indicated by arrow tb2. In this case, the relocation destination of the shelves S of pod ID_6 can be determined to be a node with a node ID close to workstation WSb.

[0046] As described above, in the embodiment, the final rearrangement position is determined by taking into consideration the score calculated from the transport frequency of each shelf S and the distance to the workstation, as well as the distance from the current position of each shelf S to the candidate rearrangement position. Specifically, among the node IDs of the candidate rearrangement destinations, the node ID with the shortest travel distance from the current position of the shelf S of the corresponding pod ID is determined as the final rearrangement position. This makes it possible to shorten the travel distance of the mobile objects m1-mN required to rearrange the shelf S, and as a result, the efficiency of the rearrangement of the shelf S can be improved. The rearrangement of the shelf S is expected to improve the efficiency of transportation.

[0047] (Variation 1) Below, a modified example of the method for determining the rearrangement position of the shelf S will be described. To further improve the efficiency of rearrangement of the shelf S, it is desirable that multiple shelves S are transported simultaneously during rearrangement. When multiple shelves S are transported simultaneously, it is desirable that collisions do not occur on the transport paths of the multiple moving bodies. This is because if a collision occurs on the transport paths, it will be necessary to have one of the moving bodies wait in a position where it does not interfere with the movement of the other moving bodies.

[0048] Therefore, if a collision occurs on the transport route in the operation plan for each moving body generated based on the rearrangement position of each shelf S, the management unit 11 may change at least one rearrangement position to another position. Note that if there is room for the moving body to wait, the process of changing the rearrangement position may be omitted.

[0049] FIG. 11 is a conceptual diagram of a change in rearrangement position. For example, in FIG. 11, assume that the node ID of the rearrangement position of shelf S of pod ID_8 is determined to be node ID_F9. On the other hand, in FIG. 11, assume that the node ID of the rearrangement position of shelf S of pod ID_33 is determined to be node ID_A8. In this case, if an operation plan is generated simply to ensure the shortest transport route, both the transport route for transporting shelf S of pod ID_8 and the transport route for transporting shelf S of pod ID_33 will be transport route r2. In other words, a collision of transport routes will occur.

[0050] In this case, the management unit 11 changes the node ID of the rearrangement position of the shelf S of the pod ID_8 to, for example, node ID_F6. As a result, the transport route for transporting the shelf S of the pod ID_8 is changed to the transport route r1. Therefore, a collision on the transport route is avoided.

[0051] When a transport path collision occurs, the node ID to be changed to may be, for example, the node ID with the smallest score and the shortest distance from the current shelf position among the remaining candidate node IDs for the rearrangement position. Furthermore, a transport path collision may occur regardless of which of the remaining candidate node IDs for the rearrangement position is adopted. In this case, node IDs of nodes near the candidate node IDs may be added to the candidate relocation positions. As shown in equation (1), the score s is calculated according to the distance from each node ID to workstations WSa and WSb. Therefore, even if a node with a node ID near the original candidate node ID does not obtain the smallest score, it is highly likely that it will obtain a score equivalent to that of the original candidate node ID. Therefore, even if a node with a node ID near the original candidate node ID obtains a score equivalent to that of the original candidate node ID, an efficiency improvement almost equivalent to that of relocating to the original candidate node ID can be expected.

[0052] Furthermore, whether rearrangement actually improves transport efficiency can be determined by comparing the scores s before and after rearrangement. In other words, if the improvement rate of the score s, which is based on the score s for the node ID of the node where the shelf S is located before rearrangement and the score s for the node ID of the node where the shelf S is located after rearrangement, is high, it means that the transport efficiency will be improved by the rearrangement. The improvement rate of the score s is, for example, the ratio of the scores s before and after the rearrangement. For example, if the rearrangement changes the position of the shelf S from a position far from a workstation with a high transport frequency to a position close to it, the ratio of the scores s will be smaller than a threshold. On the other hand, if the position of the shelf S remains almost unchanged even after the rearrangement, the ratio of the scores s will exceed the threshold. A shelf S whose transport efficiency is poor even after such rearrangement may be excluded from the target for rearrangement. Furthermore, the management unit 11 may notify the user of the management device 100 of the improvement rate of transport efficiency due to the rearrangement. This notification can be made by any method, such as display.

[0053] As described above, in the first modification, the rearrangement position is changed so as to prevent collisions on the transport path, thereby making it possible to further improve the efficiency of rearrangement.

[0054] (Variation 2) A method for further improving the efficiency of rearrangement compared to the methods described in the embodiment and the method described in Modification Example 1 is to circulate the rearrangement positions of the shelves. Fig. 12 is a diagram showing an example of circulating arrangement. In Fig. 12, shelves S with pod IDs 4, 10, 15, 29, and 32 are shelves included in the circulating arrangement. Circulating arrangement is a determination method for circulating the rearrangement positions by shifting the rearrangement destinations by one among multiple shelves. Specifically, the management unit 11 determines that the rearrangement position of the shelf S of pod ID_29 located at node ID_F7 will be node ID_C9 indicated by arrow R21a, the rearrangement position of the shelf S of pod ID_15 located at node ID_C9 will be node ID_A4 indicated by arrow R22, the rearrangement position of the shelf S of pod ID_4 located at node ID_A4 will be node ID_C4 indicated by arrow R23, the rearrangement position of the shelf S of pod ID_10 located at node ID_C4 will be node ID_F3 indicated by arrow R24, and the rearrangement position of the shelf S of pod ID_29 located at node ID_F3 will be node ID_F7 indicated by arrow R25. In this case, collisions on the transport paths do not occur by moving another shelf that is to be the rearrangement destination as the rearrangement source at the time the rearrangement source shelf starts to move to the rearrangement destination. Furthermore, by assigning the task of rearranging each shelf to five mobile units, the same number as the number of rearrangement positions included in the circular arrangement, rearrangement of all shelves S can be completed by each mobile unit performing a single transport. In particular, by determining the rearrangement positions of each shelf S so that the transport paths of each mobile unit are approximately the same length, the time required to rearrange each shelf S becomes equivalent. As a result, the efficiency of rearrangement can be further improved.

[0055] Here, multiple circular arrangements may be implemented as long as no collisions occur on the transport routes. Furthermore, although five shelves S are included in one circular arrangement in Figure 12, the number of shelves S included in one circular arrangement is not limited to five. For example, by changing the rearrangement position of the shelf S of pod ID_29 located at node ID_F7 to node ID_F9 indicated by arrow R21b, the loop will not close, and the number of shelves S included in the circular arrangement can be increased.

[0056] Here, even in the case of circular arrangement, shelves S do not necessarily have to be transported simultaneously. For example, shelves S may be transported sequentially. FIG. 13 is a diagram illustrating an example of sequential transport in the case of circular arrangement. In sequential transport, shelves S are transported one by one. In this case, when the first rearrangement is performed, shelves S will still exist at the rearrangement position. For example, if the shelf S of pod ID_15 at node ID_C9 is first rearranged to node ID_A4 indicated by arrow R22, the shelf S of pod ID_4 will still exist at node ID_A4. In this case, as indicated by arrow r3 in FIG. 13, the shelf S of pod ID_4 is first transported to the temporary position, and then the shelf S of pod ID_15 is transported. Thereafter, shelves S of pod IDs 15, 32, 10, and 4 are transported in this order, for example. Such sequential transport can be performed even when the number of moving objects to which the rearrangement task can be assigned is smaller than the number of shelves included in the circular arrangement. Furthermore, sequential transportation does not necessarily have to be performed only in the case of circular arrangement. For example, as shown in FIG. 13, sequential transportation can be performed even when the loop is not closed, such as when the rearrangement position of the shelf S of pod ID_29 located at node ID_F7 is changed to node ID_F9, as indicated by arrow R21b. Sequential transportation may be performed in descending order of the improvement rate of transportation efficiency, i.e., in descending order of the ratio of the score s before and after rearrangement. In this case, if the improvement rate of transportation efficiency of the shelf S of pod ID_4 is high, the shelf S of pod ID_4 may be transported to the temporary position first, and then, when the rearrangement position for pod ID_4 becomes available, the shelf S of pod ID_4 may be transported to the rearrangement position. Furthermore, if the rearrangement position for pod ID_4 becomes available before the shelf S of pod ID_4 is transported to the temporary position, the transportation of the shelf S of pod ID_4 to the temporary position may be canceled at that time, and the shelf S of pod ID_4 may be transported to the rearrangement position.

[0057] As described above, in the second modification, by making the rearrangement positions of the shelves S go around in a circle, it is possible to further improve the efficiency of rearrangement.

[0058] (Variation 3) Some workstations are divided into workstations dedicated to receiving and workstations dedicated to retrieving. At workstations dedicated to receiving, only the task of storing goods onto shelves is performed. On the other hand, at workstations dedicated to retrieving, only the task of retrieving goods from shelves is performed. In such cases, it is desirable to determine the relocation position by taking into consideration information on whether the shelf is empty, in addition to the score and the distance from the current position of each shelf S to the candidate relocation position.

[0059] Fig. 14 is a conceptual diagram of a method for determining a rearrangement position when the workstations are divided into a dedicated receiving workstation and a dedicated shipping workstation. In Fig. 14, workstation WSa is a dedicated receiving workstation, and workstation WSb is a dedicated shipping workstation.

[0060] Basically, empty shelves S are transported to a workstation dedicated to receiving goods. Conversely, basically, non-empty shelves S are transported to a workstation dedicated to retrieval goods. Therefore, it is desirable that empty shelves S be placed near workstation WSa. On the other hand, it is desirable that non-empty shelves S be placed near workstation WSb. However, among non-empty shelves S, shelves S with a high transport frequency are desirably placed closer to workstation WSb than shelves S with a low transport frequency. For example, when an empty shelf S1 as a target for rearrangement is located at a node ID far from workstation WSa, its rearrangement position is determined to be closer to workstation WSa, as shown by arrow R31. Also, when a non-empty shelf S2 as a target for rearrangement that is infrequently transported is located at a node ID far from workstation WSb, its rearrangement position is determined to be closer to workstation WSb, as shown by arrow R32. Also, when a non-empty shelf S3 as a target for rearrangement that is frequently transported is located at a node ID far from workstation WSb, its rearrangement position is determined to be closer to workstation WSb than shelf S2, as shown by arrow R33. The score s for determining such a rearrangement position can be calculated, for example, according to the following formula (2). s = (1 - w) (fa × da) + w (fb × db) (2) Here, w in equation (2) is a weighting coefficient and takes the value of 0 or 1. Specifically, w for an empty shelf S is 0, and w for a non-empty shelf S is 1. For simplicity, w takes the value of 0 or 1, but it may also take a value greater than or equal to 0 and less than or equal to 1 depending on the amount of luggage remaining on the shelf. In this case, the shelf S with more inventory is placed closer to workstation WSb. Furthermore, equation (2) is for calculating the score when there are two workstations. Like equation (1), equation (2) can also be expanded to cases where there are three or more workstations.

[0061] As described above, in the third modification, the rearrangement position is determined depending on the type of workstation and whether the shelf S is empty or not, thereby making it possible to further improve the transport efficiency.

[0062] (Variation 4) In the above-described embodiment and modified examples, it is assumed that all shelves S face the aisle. In this case, the moving object can immediately move to the destination position. However, not all shelves S are necessarily arranged to face the aisle, and they may be arranged densely as shown in FIG. 15. If the shelf S to be rearranged is surrounded by other shelves S, the other shelves S must be transported first. Therefore, in the case of a dense arrangement such as that shown in FIG. 15, even if the transport frequency of the shelves S not facing the aisle, shown in areas A1 and A2, is high, the management unit 11 determines the rearrangement position of at least one shelf S adjacent to areas A1 and A2 before the shelf S. For example, if the transport frequency of the shelf S located at node ID_D7 is the highest, the management unit 11 first determines the rearrangement position of the shelf S located at node ID_D6 or node ID_D8, and then determines the rearrangement position of the shelf S located at node ID_D7. Here, the rearrangement position of the shelf S located at node ID_D6 or node ID_D8 may be the temporary position described in modified example 2.

[0063] The same applies to a dense arrangement in which the shelf S to be rearranged is arranged with two or more shelves S between them and an aisle, as shown in Figure 16. The management unit 11 determines the rearrangement position in order, starting with the shelf S facing the aisle, even if the transport frequency of the shelf S that does not face the aisle, as shown in area A3, is high. For example, if the transport frequency of the shelf S located at node ID_D6 is the highest, the management unit 11 determines the rearrangement position of the shelf S located at node ID_D8, then determines the rearrangement position of the shelf S located at node ID_D7, and then determines the rearrangement position of the shelf S located at node ID_D6. Here, the rearrangement positions of the shelves S located at node ID_D8 and node ID_D7 may be the temporary positions described in Modification Example 2.

[0064] As described above, in the fourth modification, even if the shelves S are densely arranged, the rearrangement positions are appropriately determined.

[0065] (Variation 5) In the above-described embodiment, basically, all shelves S can be subject to rearrangement. However, by utilizing the improvement rate of transport efficiency, i.e., the score s before and after rearrangement, the number of shelves S subject to rearrangement can be reduced.

[0066] 17 is a conceptual diagram of a method for determining a rearrangement position that takes into account the improvement rate of transport efficiency. In Modification 5, the final rearrangement position is determined not in descending order of score, but in descending order of improvement rate of transport efficiency, i.e., the smallest score ratio. Then, when the number of shelves S that need to be moved reaches a certain number, the determination of the rearrangement position is terminated. A specific explanation will be given below. In the following specific example, an example in which the certain number is 5 will be described.

[0067] 17 shows an example in which the relocation position of shelf S of pod ID_3 in node ID_A3 is initially determined to be node ID_F1, as indicated by arrow R41. In this case, there are two shelves S that need to be moved: the shelf S of node ID_A3 and the shelf S of node ID_F1. In this case, the number of shelves S that need to be moved does not reach a certain number, so determination of the relocation positions continues.

[0068] Next, an example is shown in which the relocation position of shelf S of pod ID_6 in node ID_A6 has been determined to be node ID_F4, as indicated by arrow R42. In this case, there are four shelves S that need to be moved: shelf S of node ID_A3, shelf S of node ID_F1, shelf S of node ID_A6, and shelf S of node ID_F4. In this case, the number of shelves S that need to be moved does not reach the fixed number, so determination of relocation positions continues.

[0069] Next, an example is shown in which the relocation position of shelf S for pod ID_27 in node ID_E9 has been determined to be node ID_A6, as indicated by arrow R43. In this case, there are five shelves S that need to be moved: shelf S for node ID_A3, shelf S for node ID_F1, shelf S for node ID_A6, shelf S for node ID_F4, and shelf S for node ID_E9. In this case, the number of shelves S that need to be moved has reached a certain number, so determination of the relocation position is completed.

[0070] As explained above, in Modification 5, the efficiency of the process of determining the rearrangement position can be improved by reducing the number of shelves S to be rearranged. Furthermore, since the rearrangement position is determined in descending order of improvement rate, improvement in transport efficiency is expected even when the number of shelves S to be rearranged is small.

[0071] Next, a description will be given of an example of the hardware configuration of the management device 100. Fig. 18 is a diagram showing an example of the hardware configuration of the management device 100. As shown in Fig. 18, the management device 100 is a computer having a processor 101, an input interface 102, a display 103, a communication device 104, a memory 105, and a storage 106. The processor 101, the input interface 102, the display 103, the communication device 104, the memory 105, and the storage 106 are connected via a bus 107.

[0072] The processor 101 controls the overall operation of the management device 100. The processor 101 operates as a management unit 11, an operation plan generation unit 12, an operation control unit 13, a mobile object management unit 14, and a communication unit 15 by executing, for example, a management program 1061 stored in the storage 106. The processor 101 is, for example, a CPU. The processor 101 may be an MPU, a GPU, an ASIC, an FPGA, or the like. The processor 101 may be a single CPU or the like, or may be multiple CPUs or the like.

[0073] The input interface 102 includes input devices such as a touch panel, a keyboard, a mouse, etc. When the input device is operated, a signal corresponding to the operation is input to the processor 101 via the bus 107. The processor 101 performs various processes in response to this signal.

[0074] The display 103 is a display such as a liquid crystal display, an organic EL display, etc. The display 103 can be used to notify the user of the management device 100 of the improvement rate, for example.

[0075] The communication device 104 is a device that allows the management device 100 to communicate with an external device. The communication device 104 operates together with the processor 101 as the communication unit 15. The external device is, for example, a mobile object. The communication device 104 may be a communication device for wired communication or a communication device for wireless communication.

[0076] The memory 105 includes a ROM and a RAM. The ROM is a non-volatile memory. The ROM stores a startup program for the management device 100 and the like. The RAM is a volatile memory. The RAM is used as a working memory during processing by the processor 101, for example.

[0077] The storage 106 is, for example, a storage such as a hard disk drive or a solid state drive. The storage 106 stores various programs executed by the processor 101, such as a management program 1061. The storage 106 may also store a travel area DB 21, a node DB 22, a link DB 23, a moving object DB 24, a task DB 25, and an operation plan DB 26. The travel area DB 21, the node DB 22, the link DB 23, the moving object DB 24, the task DB 25, and the operation plan DB 26 may be stored in a server or the like that can communicate with the management device 100. In this case, the management device 100 transmits and receives necessary data to and from the server using the communication device 104.

[0078] The instructions shown in the processing procedures described in the above-described embodiments can be executed based on a software program. A general-purpose computer system can store this program in advance and, by loading this program, achieve effects similar to those achieved by the management device described above. The instructions described in the above-described embodiments can be recorded as a computer-executable program on a magnetic disk (flexible disk, hard disk, etc.), an optical disk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD±R, DVD±RW, Blu-ray (registered trademark) Disc, etc.), semiconductor memory, or similar recording medium. The recording medium may take any storage format as long as it is readable by a computer or embedded system. A computer can achieve operations similar to those of the management device described in the above-described embodiments by loading the program from the recording medium and having the CPU execute the instructions described in the program based on the program. Of course, the computer may acquire or load the program via a network. In addition, an OS (operating system), database management software, network middleware, etc. running on a computer may execute some of the processes required to realize this embodiment based on instructions from a program installed on the computer or embedded system from a recording medium. Furthermore, the recording medium in this embodiment is not limited to a medium independent of a computer or an embedded system, but also includes a recording medium that stores or temporarily stores a program downloaded via a LAN, the Internet, or the like. Furthermore, the number of recording media is not limited to one, and cases where the processing in this embodiment is executed from multiple media are also included in the recording media in this embodiment, and the media may have any configuration.

[0079] The computer or embedded system in this embodiment is for executing each process in this embodiment based on a program stored on a recording medium, and may be configured as either a device consisting of a single device such as a personal computer or a microcomputer, or a system in which multiple devices are connected to a network. Furthermore, the computer in this embodiment is not limited to a personal computer, but also includes an arithmetic processing unit, a microcomputer, etc. included in information processing equipment, and is a general term for equipment or devices that can realize the functions in this embodiment by a program.

[0080] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0081] 11 Management unit, 12 Operation plan generation unit, 13 Operation control unit, 14 Mobile object management unit, 15 Communication unit, 21 Travel area database (DB), 22 Node DB, 23 Link DB, 24 Mobile object DB, 25 Task DB, 26 Operation plan DB, 100 Management device, 101 Processor, 102 Input interface, 103 Display, 104 Communication device, 105 Memory, 106 Storage, 107 Bus, 1061 Management program.

Claims

1. A score is calculated based on the frequency of transport for each workstation of each shelf arranged in the facility and the distance between each of the shelves and the workstation; determining a rearrangement position of each of the shelves based on the score and the current position of each of the shelves; A management device for a mobile object, comprising a management unit.

2. The transport frequency is the transport frequency for a specified period in the past. The mobile object management device according to claim 1 .

3. the transportation frequency is a transportation frequency counted based on order information that determines future task allocation of the mobile body; The mobile object management device according to claim 1 .

4. the distance is the Manhattan distance between each of the shelves and a representative point of the workstation; The mobile object management device according to claim 1 .

5. The management unit determines the rearrangement positions of the shelves in order of the score or the rate of improvement in the score before and after the rearrangement. The mobile object management device according to claim 1 .

6. the management unit determines the rearrangement positions so that the rearrangement positions of at least some of the shelves are shifted one by one to complete a complete circuit; The mobile object management device according to claim 1 .

7. The number of rearrangement positions in the circle is the same as the number of moving bodies. The mobile object management device according to claim 6.

8. The workstations are divided into workstations dedicated to receiving goods and workstations dedicated to retrieving goods, determining a rearrangement position of each of the shelves based on the score, the current position of each of the shelves, and whether the shelf is empty; The mobile object management device according to claim 1 .

9. the management unit excludes a shelf with a poor improvement rate in the score before and after the rearrangement from the target for determining the rearrangement position. The mobile object management device according to claim 1 .

10. the management unit determines a rearrangement position of each of the plurality of shelves so that collisions do not occur on the transport path when the shelves are rearranged. The mobile object management device according to claim 1 .

11. the management unit displays on a display device an improvement rate of the score before and after the rearrangement. The mobile object management device according to claim 1 .

12. an operation plan generation unit that generates an operation plan for the moving body so as to transport the shelf to the rearrangement position; the management unit controls the operation of the moving body so that, at a timing when the first moving body starts to move the first shelf to the rearrangement position based on the operation plan, the second moving body moves the second shelf whose rearrangement position is the first shelf. The mobile object management device according to claim 1 .

13. the management unit moves the moving objects in descending order of improvement rate of the score before and after the rearrangement. The mobile object management device according to claim 12.

14. the management unit controls the operation of the mobile body so that at least one shelf is transported to a temporary position by the mobile body prior to starting the transport of the shelf to the rearrangement position. The mobile object management device according to claim 12.

15. Calculating a score based on the frequency of transport for each workstation of each shelf arranged in the facility and the distance between each of the shelves and the workstation; determining a rearrangement position of each of the shelves based on the score and the current position of each of the shelves; A mobile object management method comprising:

16. Calculating a score based on the frequency of transport for each workstation of each shelf arranged in the facility and the distance between each of the shelves and the workstation; determining a rearrangement position of each of the shelves based on the score and the current position of each of the shelves; A mobile object management program for causing a computer to execute the above.

Images