Conveying system

Abstract

To improve a carry efficiency.SOLUTION: A carrier system 1 comprises: a plurality of carrier vehicles 30 each capable of carrying an object to be carried from a transfer station 41; a system controller 60 that controls the plurality of carrier vehicles 30; and waiting points 50 that are provided correspondingly to the transfer stations 41 and where the carrier vehicles 30 can wait, wherein: the system controller 60 grasps exit of one of the carrier vehicles 30 at one of the waiting points 50; and based on the exiting of the one of the carrier vehicles 30, the system controller assigns a travel command to another one of the carrier vehicles 30 other than the one of the carrier vehicles 30, to the one of the waiting points 50.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a conveyance system.

Background Art

[0002] There is known a conveyance system including an automated guided vehicle capable of conveying an object to be conveyed from a transfer station, and a controller for controlling a plurality of automated guided vehicles. As this type of technology, for example, Patent Document 1 discloses that a controller causes an automated guided vehicle that has completed a predetermined operation to travel to a place where the frequency of conveyance requests is high and wait at that place.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conveyance system as described above, when a conveyance request is issued, by assigning a conveyance command to an automated guided vehicle waiting at a waiting point (a place where the frequency of conveyance requests is high), the waiting time until the automated guided vehicle arrives at the conveyance source is reduced, and the conveyance efficiency is improved. However, in this case, the response when the automated guided vehicle is absent at the waiting point is not sufficiently made, and there is still room for improvement in improving the conveyance efficiency.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a conveyance system capable of improving conveyance efficiency.

Means for Solving the Problems

[0006] The transport system according to the present invention comprises a plurality of automated guided vehicles (AGVs) capable of transporting objects from a transfer station, a controller for controlling the plurality of AGVs, and a waiting point provided corresponding to the transfer station where AGVs can wait. The controller has a waiting vehicle control unit that detects when an AGV leaves the waiting point and, based on the departure of an AGV, assigns a travel command to the waiting point to another AGV, separate from the one in question.

[0007] In this transport system, the standby vehicle control unit can detect when an automated guided vehicle (AGV) leaves a standby point and quickly assign a travel command to another AGV heading towards the standby point. That is, for example, when an AGV currently at a standby point starts traveling or when travel is planned, another AGV can be dispatched to that standby point. This reduces the time when an AGV is absent from a standby point and reduces the waiting time until an AGV arrives at the transfer station from which it was originally intended when a transport request is made. Therefore, this transport system can improve transport efficiency.

[0008] In the transport system according to the present invention, the automated guided vehicle (AGV) travels along a predetermined route, and the transfer stations and waiting points are arranged along the route. The waiting points may be located near the corresponding transfer stations. In this case, since the AGV can travel from the waiting point to the transfer station in a short time, it is possible to effectively reduce the waiting time from when a transport request is made until the AGV is dispatched from the corresponding waiting point to the transfer station.

[0009] In the transport system according to the present invention, the controller stores a transfer station and a corresponding waiting point in association with that transfer station, and does not need to assign a transport command to an automated guided vehicle (AGV) that is present at or scheduled to be present at a waiting point, to transport an object from a transfer station other than the one stored in association with that waiting point. In this case, an AGV present at or scheduled to be present at a waiting point will not leave the waiting point for transport from a transfer station other than the one corresponding to that waiting point. Therefore, the amount of time that an AGV is absent from the waiting point can be reduced.

[0010] In the transport system according to the present invention, the standby vehicle control unit may detect the departure of an automated guided vehicle (AGV) from a standby point based on the travel plan of the AGV currently present at or scheduled to be present at the standby point to a charging station. In this case, it becomes possible to detect when an AGV will be absent from the standby point due to travel to a charging station.

[0011] In the transport system according to the present invention, the standby vehicle control unit may determine when an automated guided vehicle (AGV) leaves a standby point based on the assignment of commands to AGVs that are present at or scheduled to be present at the standby point. In this case, since the departure of an AGV is determined by the assignment of commands to AGVs that are present at or scheduled to be present at the standby point, it becomes possible to assign a travel command to another AGV to the standby point before the AGV physically leaves the standby point.

[0012] In the transport system according to the present invention, the standby vehicle control unit may determine the time required for other automated guided vehicles (AGVs) that have not been assigned a command to travel to the standby point, and the time required for other AGVs that have been assigned a command to travel to the standby point after the completion of the command, and assign a command to travel to the standby point to the AGV with the shortest travel time to travel to the standby point among a plurality of other AGVs. In this case, it becomes possible to assign a command to travel to the standby point to other AGVs by giving priority consideration to the travel time to travel to the standby point.

[0013] In the transport system according to the present invention, the automated guided vehicle (AGV) transports the object to be transported from the first transfer station to the second transfer station, and then stays at a waiting point corresponding to the second transfer station. The waiting vehicle control unit may, when a transport command to transport the object to be transported to the second transfer station is assigned to the AGV, determine the departure of the AGV from the waiting point corresponding to the second transfer station based on the transport command and the AGV's charge level. This makes it possible to determine when the AGV will be absent from the waiting point when the transport vehicle is transporting the object to the second transfer station, by using the transport command and the AGV's charge level. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a transport system that can improve transport efficiency. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a schematic diagram of a transport system according to one embodiment. [Figure 2] Figure 2(a) is a schematic front view showing the automated guided vehicle and transfer station of Figure 1. Figure 2(b) is a schematic side view showing the automated guided vehicle and transfer station of Figure 1. Figure 2(c) is a schematic side view showing the transfer station of Figure 1. [Figure 3]Figure 3 is a functional block diagram showing the controller in Figure 1. [Figure 4] Figure 4 is a flowchart showing an example of the processing performed by the standby vehicle control unit in the transport system shown in Figure 1. [Modes for carrying out the invention]

[0016] An embodiment will be described below with reference to the drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numeral, and redundant descriptions are omitted. The dimensional ratios in the drawings do not necessarily match those in the description.

[0017] As shown in Figure 1, the transport system 1 is a system that constitutes a transport system for transporting goods L (an example of an object to be transported) that have been dispatched from, for example, an outbound conveyor W of an automated warehouse in a factory. The size, shape, and weight of the goods L are not particularly limited, and any object can be used as goods L. The transport system 1 includes a waiting point 50, a plurality of transport vehicles 30 (an example of an automated guided vehicle), and a system controller 60 (an example of a controller).

[0018] Multiple transfer stations 41 and one or more charging stations 42 are installed on the floor F of the factory where the transport system 1 is installed. The number of transfer stations 41 and charging stations 42 installed in the transport system 1 is not particularly limited.

[0019] The transfer station 41 is a place where the goods L are placed, and includes a first transfer station 43, a second transfer station 44, a third transfer station 45, and a fourth transfer station 46. The transfer station 41 is located along the route of the transport vehicle 30, which will be described later. The first transfer station 43 is, for example, a dispatch station located on the dispatch conveyor W of an automated warehouse. The first transfer station 43 constitutes the source of transport. The first transfer station 43 transfers the goods L to the transport vehicle 30. The first transfer station 43 is a station that is not designated as a destination (it does not receive goods L from the transport vehicle 30).

[0020] The second transfer station 44 and the third transfer station 45 are provided, for example, in the central region of the floor F. The second transfer station 44 and the third transfer station 45 are provided, for example, adjacent to each other. The second transfer station 44 and the third transfer station 45 constitute both the transfer source and the transfer destination. The second transfer station 44 and the third transfer station 45 are stations where the article L is transferred to the transport vehicle 30 and the article L is transferred from the transport vehicle 30. The second transfer station 44 and the third transfer station 45 are first stations designated as the transfer destination to receive the article L from the transport vehicle 30, and then stations designated as the transfer source to deliver the article L to the transport vehicle 30.

[0021] The second transfer station 44 is, for example, a temporary placement place for the article L. The third transfer station 45 is, for example, a picking station for performing a predetermined operation by the robot arm 47. The fourth transfer station 46 is provided, for example, in the end region of the floor F. The fourth transfer station 46 constitutes the transfer destination. The fourth transfer station 46 is a station where the article L is transferred from the transport vehicle 30. The fourth transfer station 46 is a station that is not designated as the transfer source (and does not deliver the article L to the transport vehicle 30).

[0022] As shown in FIGS. 2(a), 2(b) and 2(c), each transfer station 41 has, for example, a mounting table 41a on which the article L can be placed. The X direction, Y direction and Z direction in FIGS. 2(a), 2(b) and 2(c) refer to the axial directions in the orthogonal coordinate system of the three-dimensional space set for convenience of explanation. The X direction and the Y direction are directions along the floor F, and the Z direction is the vertical direction (lifting direction). The mounting tables 41a in the first transfer station 43 and the fourth transfer station 46 are composed of various conveyors such as, for example, a belt conveyor, a chain conveyor or a roller conveyor. The mounting tables 41a in the second transfer station 44 and the third transfer station 45 are composed of, for example, pedestals.

[0023] As shown in Figure 1, the charging station 42 is an area where the transport vehicle 30 can be automatically charged. The charging stations 42 are located at the four corners of the entire area, which consists of multiple passage areas 40. The number of charging stations 42 is determined on the floor F, for example, according to the number of transport vehicles 30. The configuration of the charging equipment in the charging station 42 is not particularly limited.

[0024] As shown in Figures 1 and 2, the waiting point 50 is a location where the transport vehicle 30 can wait. The waiting point 50 is provided in correspondence with the transfer station 41. The waiting point 50 is provided in the vicinity of the corresponding transfer station 41. Vicinity means, for example, a surrounding location, a nearby location, an approaching location, an adjacent location, etc. The waiting point 50 is a stopping position for the transport vehicle 30 to wait, set in the control system on the floor F. The waiting point 50 corresponding to the transfer station 41 means a stopping position where the transport vehicle 30 traveling to the transfer station 41 will wait. The waiting point 50 is an area in which at least one transport vehicle 30 can stop. The waiting point 50 can be set in the system controller 60. The waiting point 50 is provided along the route of the transport vehicle 30, which will be described later.

[0025] The standby point 50 includes a first standby point 51, a second standby point 52, and a third standby point 53. Each of the first standby point 51, the second standby point 52, and the third standby point 53 is comprised of a first transfer station 43, a second transfer station 44, and a third transfer station 45, respectively. As an example, the standby point 50 is set in the space below the mounting platform 41a of the transfer station 41. In this case, in a plan view, the standby point 50 is positioned overlapping with the transfer station 41.

[0026] The transport vehicle 30 travels, for example, on the floor F. The transport vehicle 30 is an unmanned transport trolley. The transport vehicle 30 travels along a predetermined route. The route is a route set up on the floor F in the control system. For example, the route is set to pass through at least one of the transfer station 41, the charging station 42, and the waiting point 50. The route is set up on a plurality of travel areas 40 set up on the floor F. The route may also be a virtual travel path set up based on the position information of the transport vehicle 30. The route may be composed of, for example, magnetic tape (magnetic marker), laser reflector, floor track, ceiling track, or rail.

[0027] The passage area 40 is an area recognized by the transport vehicle 30, for example, by a position marker, and is an area in which the transport vehicle 30 can travel and stop. In Figure 1, the passage area 40 is shown as a rectangular section for the sake of explanation, but it can be a virtual area in the system controller 60, and it is not necessary for a rectangular section to be actually provided.

[0028] The transport vehicle 30 is capable of transporting goods L from one transfer station 41 to another transfer station 41. The transport vehicle 30 is capable of transferring (receiving) goods L between transfer stations 41. An AGV (Automatic Guided Vehicle) is used as the transport vehicle 30. However, the transport vehicle 30 is not particularly limited to an AGV, and may be, for example, an overhead vehicle or a tracked trolley.

[0029] The transport vehicle 30 has a vehicle body 31 that travels guided along a path, and a lifter 32 provided on the vehicle body 31 for raising and lowering the item L. The vehicle body 31 can enter the loading platform 41a of the transfer station 41. The transport vehicle 30 that transports the item L can enter the loading platform 41a with the lifter 32 raised. The transport vehicle 30 transfers the item L to the loading platform 41a by lowering the lifter 32. The transport vehicle 30 with the lifter 32 lowered transfers the item L on the loading platform 41a onto the lifter 32 by raising the lifter 32 within the loading platform 41a.

[0030] The transport vehicle 30 has a transport vehicle controller 33. The transport vehicle controller 33 comprehensively controls the transport vehicle 30. The transport vehicle controller 33 is a computer having a ROM (Read Only Memory) where programs are stored, a RAM (Random Access Memory) for temporarily storing data, a storage medium such as an HDD (Hard Disk Drive), a CPU (Central Processing Unit), and communication circuits such as a wireless LAN. The transport vehicle controller 33 can be configured as software in which, for example, a program stored in ROM is loaded onto RAM and executed by the CPU. The transport vehicle controller 33 may also be configured as hardware using electronic circuits, etc. The transport vehicle controller 33 may consist of one device or multiple devices. If it consists of multiple devices, these are connected via a communication network such as the Internet or an intranet to logically construct a single transport vehicle controller 33.

[0031] The transport vehicle controller 33 communicates wirelessly with the outside of the transport vehicle 30. The transport vehicle controller 33 communicates with the system controller 60 via an access point (not shown). The transport vehicle controller 33 transmits information about the transport vehicle 30, such as its location, speed, and charge level, to the system controller 60. For example, when the charge level of the transport vehicle 30 falls below a threshold, the transport vehicle controller 33 sends a charging request to the system controller 60 to drive the transport vehicle 30 to the charging station 42.

[0032] When the transport vehicle controller 33 receives a travel command (described later) from the system controller 60, it performs travel control to transport the transport vehicle to the destination point of the travel command. When the transport vehicle controller 33 receives a transport command (described later) from the system controller 60, it performs travel control and loading / unloading control to transport the goods L from the source transfer station 41 to the destination transfer station 41 of the transport command. For example, SLAM (Simultaneous Localization and Mapping) technology may be used as the guidance method for the travel control. In loading / unloading control, the lifter 32 is raised and lowered to load the goods from the transfer station 41 to the transport vehicle 30 and unload the goods from the transport vehicle 30 to the transfer station 41.

[0033] The system controller 60 is a control device that manages the transport system 1. The system controller 60 is a computer having storage media such as ROM, RAM, and HDD, a CPU, and communication circuits. The system controller 60 can be configured as software, for example, in which a program stored in ROM is loaded onto RAM and executed by the CPU. The system controller 60 may also be configured as hardware, such as electronic circuits. The system controller 60 may consist of one device or multiple devices. If it consists of multiple devices, these are connected via a communication network such as the Internet or an intranet to logically construct a single system controller 60.

[0034] The system controller 60 is connected to the transport vehicle controller 33 and a higher-level controller (not shown) by wire or wireless connection. The system controller 60 receives information about the transport vehicle 30, such as its location, speed, and charge level, via the transport vehicle controller 33. The system controller 60 receives charging requests for the transport vehicle 30 via the transport vehicle controller 33. The system controller 60 receives transport requests from the controllers to transport an item L from one transfer station 41 to another transfer station 41. The system controller 60 assigns commands to the transport vehicle 30 according to the received information and requests. Requests include charging requests and transport requests. Commands include transport commands and driving commands.

[0035] A transport command is a control command for transporting an item L from the source transfer station 41 to the destination transfer station 41 in a transport request using a transport vehicle 30. The transport command includes information regarding the transfer of the item L at the source transfer station 41, the journey from the source transfer station 41 to the destination transfer station 41, and the transfer of the item L at the destination transfer station 41. The transport command may include a control command for the transport vehicle 30 to wait at a waiting point 50 corresponding to the destination transfer station 41 after transport. In this case, the transport command includes information regarding waiting at the waiting point 50. A travel command is a control command for transporting the transport vehicle 30 to a destination point (such as a transfer station 41, charging station 42, or waiting point 50). The travel command includes information regarding the journey to the destination point.

[0036] The system controller 60 assigns a transport command to the transport vehicle 30 that is currently present at or scheduled to be present at the standby point 50, with the transfer station 41 corresponding to the standby point 50 as the transport source. The presence of the transport vehicle 30 corresponds to the transport vehicle 30 being physically located at the standby point 50. The scheduled presence of the transport vehicle 30 corresponds to the transport vehicle 30 being assigned a command to travel to the standby point 50 (a travel command or a transport command) (i.e., the transport vehicle 30 will later be located at the standby point 50).

[0037] As shown in Figures 1, 2, and 3, the system controller 60 has a storage unit 61 and a standby vehicle control unit 62 as functional elements that perform the functions of the transport system 1. The storage unit 61 stores a plurality of transfer stations 41 and standby points 50 corresponding to each of the plurality of transfer stations 41 in association with each other. The standby vehicle control unit 62 assigns travel commands to the transport vehicles 30. The standby vehicle control unit 62 detects when a transport vehicle 30 leaves a standby point 50 and, based on the departure of the transport vehicle 30, assigns a travel command to the standby point 50 to another transport vehicle 30 different from the transport vehicle 30. Furthermore, when the system controller 60 receives a charging request from a transport vehicle 30, the standby vehicle control unit 62 detects when the transport vehicle 30 leaves based on the charging request and assigns a travel command to the charging station 42 to the transport vehicle 30.

[0038] In the transport system 1 described above, for example, when the system controller 60 receives a transport request to transport an item L from the first transfer station 43 to the second transfer station 44, and the transport vehicle 30 is waiting at the first waiting point 51 corresponding to the first transfer station 43, the following operations are performed.

[0039] In other words, the system controller 60 generates a transport command to transport the item L by the transport vehicle 30 based on a transport request from the higher-level controller. The transport command includes information regarding the transfer of the item L at the first transfer station 43, the travel to the second transfer station 44, the transfer of the item L at the second transfer station 44, and waiting at the second waiting point 52 corresponding to the second transfer station 44.

[0040] The system controller 60 assigns a transport command to the transport vehicle 30 waiting at the first waiting point 51. Based on the assigned transport command, the transport vehicle controller 33 raises the lifter 32 and loads the goods L onto the transport vehicle 30. After the transfer of goods L to the transport vehicle 30 is complete, the transport vehicle controller 33 controls the movement of the transport vehicle 30 based on the assigned transport command and moves it from the first transfer station 43 to the second transfer station 44.

[0041] After the transport vehicle 30 moves to the second transfer station 44, the transport vehicle controller 33 lowers the lifter 32 based on the assigned transport command and unloads the item L onto the loading platform 41a of the second transfer station 44. After the transfer of item L to the second transfer station 44 is complete, the transport vehicle 30 waits at the second standby point 52, which is stored in association with the second transfer station 44. Here, since the second transfer station 44 constitutes the second standby point 52, the transport vehicle remains there after the transfer is complete.

[0042] For example, if the system controller 60 receives a transport request to transport item L from the first transport station 43 to the third transport station 45, or a transport request to transport item L from the second transport station 44 to the third transport station 45, the same operation as described above will be performed.

[0043] In this embodiment of the transport system 1, the standby vehicle control unit 62 detects when a transport vehicle 30 leaves the standby point 50 and, based on the departure of the transport vehicle 30, assigns a travel command to the standby point 50 to another transport vehicle 30, separate from the transport vehicle 30. For example, the standby vehicle control unit 62 performs the following processing shown in Figure 4.

[0044] First, the standby vehicle control unit 62 determines whether or not the departure of a transport vehicle 30 that is currently present at or scheduled to be present at the standby point 50 can be detected (step S1). Detecting the departure of a transport vehicle 30 includes not only detecting that the transport vehicle 30 has actually left, but also detecting that the transport vehicle 30 is about to leave, based on the assignment of a command or the receipt of a request, etc.

[0045] For example, in step S1 above, departure from the waiting point 50 is detected when a transport vehicle 30 that is present at or scheduled to be present at the waiting point 50 is assigned a transport command. Also, for example, in step S1 above, departure from the waiting point 50 is detected when a charge request is transmitted from a transport vehicle 30 that is present at or scheduled to be present at the waiting point 50. Also, for example, in step S1 above, departure from the waiting point 50 is detected when a drive command to a charging station 42 is assigned to a transport vehicle 30 that is present at or scheduled to be present at the waiting point 50.

[0046] For example, in step S1 above, if a sensor (not shown) installed on the transport vehicle 30 or the transfer station 41 detects that the transport vehicle 30, which was present at the waiting point 50, has moved out of the waiting point 50, then the departure from the waiting point 50 is recognized. For example, in step S1 above, if a command involving other movement (driving) is assigned to a transport vehicle 30 that is present at or scheduled to be present at the waiting point 50, then the departure from the waiting point 50 is recognized. In step S1 above, the departure from the waiting point 50 may be recognized not only when a command is assigned, but also when a command is generated.

[0047] If the standby vehicle control unit 62 determines that departure from the standby point 50 has been detected (Step S1: YES), the standby vehicle control unit 62 proceeds to the next operation. If the standby vehicle control unit 62 determines that departure from the standby point 50 has not been detected (Step S1: NO), the standby vehicle control unit 62 performs the same determination operation (Step S1) again.

[0048] If the standby vehicle control unit 62 determines that a vehicle has left the standby point 50 (Step S1: YES), the standby vehicle control unit 62 determines the time required for other transport vehicles 30 that have not been assigned a command to travel to the standby point 50, and the time required for other transport vehicles 30 that have been assigned a command to travel to the standby point 50 after the completion of the command (Step S3). Other transport vehicles 30 are, for example, transport vehicles 30 other than the transport vehicle 30 that is leaving the standby point 50. Transport vehicles 30 that have not been assigned a command are, for example, empty transport vehicles 30 that have not been assigned a command such as a travel command or a transport command.

[0049] The required time for a transport vehicle 30 that has not been assigned a command corresponds to the travel time it takes for the transport vehicle 30 to travel from its current location to the waiting point 50. The required time for a transport vehicle 30 that has been assigned a command corresponds to the sum of the time it takes for the command to be completed and the travel time it takes for the transport vehicle 30 to travel from the location where the command was completed to the waiting point 50.

[0050] Next, the standby vehicle control unit 62 determines which transport vehicle 30 will be sent to the standby point 50 (step S5). In step S5, the standby vehicle control unit 62 determines which of the multiple other transport vehicles 30 has the shortest travel time to the standby point 50 to be sent to the standby point 50.

[0051] Next, the standby vehicle control unit 62 assigns a travel command to the standby point 50 to the transport vehicle 30 determined in step S5 (step S7). As a result, the transport vehicle 30 to which the travel command has been assigned travels toward the standby point 50 and stops and waits at the standby point 50. After step S7, the processing of step S1 is executed for the transport vehicle 30.

[0052] Furthermore, in the transport system 1 of this embodiment, the system controller 60 does not assign transport vehicles 30 that are present at or scheduled to be present at the waiting point 50 a transport command to transport items L from any transfer station 41 other than those stored in association with the waiting point 50. For example, the system controller 60 assigns transport vehicles 30 that are present at or scheduled to be present at the waiting point 50 only a transport command to transport items L from a transfer station 41 stored in association with the waiting point 50, or a drive command to a charging station 42.

[0053] In the transport system 1, the standby vehicle control unit 62 can detect when a transport vehicle 30 leaves the standby point 50 and quickly assign a travel command to another transport vehicle 30 heading towards the standby point 50. That is, for example, when a transport vehicle currently at the standby point 50 starts traveling or when travel is planned, another transport vehicle 30 can be dispatched to the standby point 50. This reduces the time when a transport vehicle 30 is absent from the standby point 50, and reduces the waiting time until a transport vehicle 30 arrives at the transfer station 41 when a transport request is made. Therefore, this transport system 1 can improve transport efficiency.

[0054] The transport vehicle 30 travels along a predetermined route, and the transfer stations 41 and waiting points 50 are arranged along the route, with the waiting points 50 located near the corresponding transfer stations 41. In this case, since the transport vehicle 30 can travel from the waiting point 50 to the transfer station 41 in a short time, it is possible to effectively reduce the waiting time from when a transport request is made until the transport vehicle 30 is dispatched from the corresponding waiting point 50 to the transfer station 41.

[0055] The system controller 60 stores the transfer station 41 in association with the corresponding waiting point 50, and does not assign a transport command to a transport vehicle 30 that is currently at or scheduled to be at the waiting point 50 to transport goods L from a transfer station other than the one stored in association with the waiting point 50. In this case, a transport vehicle 30 that is currently at or scheduled to be at the waiting point 50 will not leave the waiting point 50 for transport from a transfer station other than the one corresponding to the waiting point 50. Therefore, the amount of time that the transport vehicle 30 is absent from the waiting point 50 can be reduced. As a result, when a transport request is generated at the source transfer station 41 corresponding to the waiting point 50, the waiting time until the transport vehicle 30 arrives at the source transfer station 41 can be effectively reduced.

[0056] The standby vehicle control unit 62 detects the departure of a transport vehicle 30 based on a charging request from the transport vehicle 30 that is currently at or scheduled to be at the standby point 50, or on the assignment of a driving command to the charging station 42 to the said transport vehicle 30. In other words, the standby vehicle control unit 62 detects the departure of a transport vehicle 30 from the standby point 50 based on the driving plan to the charging station 42 of the transport vehicle 30 that is currently at or scheduled to be at the standby point 50 (corresponding to the assignment of a charging request or a driving command to the charging station 42). In this case, it becomes possible to detect that the transport vehicle 30 will be absent from the standby point 50 due to driving to the charging station 42.

[0057] The standby vehicle control unit 62 determines when a transport vehicle 30 has left the standby point 50 based on the assignment of commands to transport vehicles 30 that are currently present at or scheduled to be present at the standby point 50. In this case, since the departure of a transport vehicle 30 is determined by the assignment of commands to transport vehicles 30 that are currently present at or scheduled to be present at the standby point 50, it is possible to assign a travel command to another transport vehicle 30 to the standby point 50 before the transport vehicle 30 has physically left the standby point. In conventional systems, when a transport vehicle 30 has not physically left the standby point 50, a travel command to another transport vehicle 30 was not assigned to the standby point 50.

[0058] The standby vehicle control unit 62 determines the time required for other transport vehicles 30 that have not been assigned a command to travel to the standby point 50, and the time required for other transport vehicles 30 that have been assigned a command to travel to the standby point 50 after the completion of the command. From among the multiple other transport vehicles 30, it assigns a command to travel to the standby point 50 to the transport vehicle 30 with the shortest travel time to the standby point 50. In this case, it is possible to assign a command to travel to the standby point 50 to the other transport vehicles 30 by prioritizing the travel time to the standby point 50.

[0059] Incidentally, in this embodiment, if the departure of a transport vehicle 30 from the first waiting point 51 of the first transfer station 43, which cannot be a destination, is detected, a command to travel to the waiting point may be unconditionally assigned to another transport vehicle 30. On the other hand, if the departure of a transport vehicle 30 from the second waiting point 52 and the third waiting point 53 of the second transfer station 44 and the third transfer station 45, which can be the source and destination of transport, a command to travel to the waiting point may be assigned to another transport vehicle 30 only when it is possible to transport the goods L from the second transfer station 44 and the third transfer station 45 (when the goods L are placed at the second transfer station 44 and the third transfer station 45, or after a transport request to the second transfer station 44 and the third transfer station 45 has been generated).

[0060] This section describes a first example of applying a transport system having the features of this embodiment to a factory, and its effects. Functions of the same name that are not described below are the same as those of this embodiment. The transport system in the first example includes a waiting point, a transport vehicle for transporting goods, and a system controller having a waiting vehicle control unit. The factory in the first example has two automated warehouse exits corresponding to the first transfer station 43 of this embodiment, four picking areas corresponding to the third transfer station 45, three automated warehouse inlets corresponding to the fourth transfer station 46, and four charging points corresponding to the charging station 42. The exits, picking areas, and inlets are each provided with corresponding waiting points.

[0061] A higher-level controller located in the factory sends a request for the transport of goods at the outbound port to the system controller every 30 seconds. The system controller assigns a transport vehicle a transport command that includes information such as the outbound port where goods L are loaded, the picking area to which the goods are delivered, and the inbound port where the goods are unloaded. After loading the goods at the outbound port, the transport vehicle transports them to the designated picking area. Picking of goods at the picking area is completed in 30 seconds. After loading new goods at the picking area, the transport vehicle unloads those goods at the inbound port.

[0062] In the first example of the transport system, the system controller does not assign transport vehicles that are currently or are scheduled to be at a waiting point corresponding to an exit point to transport goods from an exit point other than those stored in association with that waiting point. Furthermore, the waiting vehicle control unit assigns a travel command to a transport vehicle to a waiting point corresponding to an exit point where transport requests repeatedly occur at predetermined time intervals, or where transport requests are expected to occur in the future, regardless of whether a transport request has occurred or not.

[0063] Furthermore, the standby vehicle control unit assigns a travel command to another transport vehicle to the standby point when the transport vehicle currently present at the standby point has not physically (actually) left the standby point. The standby vehicle control unit, for example, detects the departure of a transport vehicle from a standby point based on the assignment of commands to transport vehicles present at or scheduled to be present at the standby point corresponding to the exit, and assigns a travel command to another transport vehicle to the standby point. Such commands include transport commands and other commands involving movement. In the transport system in the first example, after goods are transferred from the exit, the transport vehicle does not travel to the charging point until the goods are transported to the inbound point. After goods are transferred to the inbound point, the transport vehicle can travel to the charging point and be charged before a travel command to the standby point corresponding to the exit is assigned.

[0064] In the first case study, the number of goods shipped out per hour across the entire factory was calculated. The number of goods shipped out refers to the number of goods transported by transport vehicles from the shipping port. In the conventional system used in the factory before the transport system in the first case study was applied, transport vehicles that had not been assigned a command were driven to waiting points corresponding to shipping ports with high transport requests and kept waiting at those waiting points. In the conventional system, even after the physical departure of a transport vehicle from a waiting point corresponding to a shipping port was complete, a driving command to that waiting point was not assigned. As a result, the waiting time for other transport vehicles at that waiting point was long. In the first case study, where the above-described transport system was applied, the number of goods shipped out per hour across the entire factory (shipping capacity) improved by approximately 40% compared to the conventional system. Therefore, by having the waiting vehicle control unit detect the departure of a transport vehicle based on a command before the physical departure of a transport vehicle occurs at a waiting point and assign a driving command or transport command to other transport vehicles, the waiting time for transport vehicles at waiting points can be significantly reduced, dramatically improving the transport efficiency in factories where the transport system is introduced.

[0065] Next, a second example of applying the transport system having the features of this embodiment to a factory and its effects will be described. Functions of the same name that are not described below are the same as those of this embodiment. The transport system in the second example includes a waiting point, a transport vehicle for transporting goods, and a system controller having a waiting vehicle control unit. The factory in the second example has one exit port corresponding to the first transfer station 43 of this embodiment, two temporary storage areas corresponding to the second transfer station 44, two picking areas corresponding to the third transfer station 45, one empty box collection port corresponding to the fourth transfer station 46, and four charging points corresponding to the charging station 42. The exit port, picking areas, and inbound port are each provided with corresponding waiting points.

[0066] A higher-level controller installed in the factory sends transport requests for goods at the outbound port to the system controller at intervals of 30 to 120 seconds. The time interval at which transport requests are sent varies depending on the progress of outbound operations at the outbound port and the progress of work at the destination. The system controller assigns a transport vehicle a transport command that includes information about the outbound port where goods L are loaded, the temporary storage area and picking area at the destination, and the empty box collection area where goods are unloaded. After loading the goods at the outbound port, the transport vehicle transports the goods to the designated temporary storage area and unloads them. The transport vehicle waits at a waiting point corresponding to the temporary storage area, then loads the goods again at the temporary storage area, transports the goods to the picking area and unloads them. The picking of the contents of the goods at the picking area is completed in 15 to 270 seconds. The time for the picking operation varies depending on the information regarding the number of items to be picked, instructed by the higher-level controller. During the picking operation, the transport vehicle waits at a waiting point corresponding to the picking area. At the picking area, the contents of the items have been picked out, and the transport vehicle that has loaded the empty boxes will unload the items at the empty box collection point.

[0067] In the transport system in the second example, the system controller does not assign transport vehicles that are present or scheduled to be present at a waiting point corresponding to an exit point to transport goods from an exit point other than those stored in association with that waiting point. Furthermore, the waiting vehicle control unit assigns a travel command to a transport vehicle to a waiting point corresponding to an exit point where transport requests repeatedly occur at predetermined time intervals, or where transport requests are expected to occur in the future, regardless of whether a transport request has occurred or not. In contrast to the waiting vehicle control unit in the first example, the waiting vehicle control unit in the second example does not assign a travel command to another transport vehicle to a waiting point corresponding to an exit point when the transport vehicle present at that point has not physically (actually) left the point.

[0068] In the second example of the transport system, transport vehicles can travel to a charging point while waiting at their respective waiting points after unloading at a temporary storage area or picking area. Specifically, the waiting vehicle control unit assigns a command to a transport vehicle to a charging point based on the receipt of a charging request from a transport vehicle that is present at or scheduled to be present at a waiting point. The waiting vehicle control unit also assigns a command to a charging point based on the charge level of the transport vehicles present at or scheduled to be present at the waiting point. The waiting vehicle control unit detects when a transport vehicle present at a waiting point corresponding to a temporary storage area or picking area has left the waiting point, based on the receipt of a charging request or a command to a charging point from a transport vehicle present at or scheduled to be present at that waiting point, even if the transport vehicle has not physically (actually) left the waiting point. After this detection, the waiting vehicle control unit assigns a command to another transport vehicle to that waiting point. It should also be noted that transport vehicles can travel to a charging point and charge after unloading goods (empty boxes) at the empty box collection port, before being assigned a command to a waiting point corresponding to the outbound port.

[0069] In the second case study, the total time for transporting goods throughout the factory was calculated as the time from when all goods were retrieved from the automated warehouse until all goods supplied to the picking area were received. In the conventional system used in the factory before the transport system in the second case study was applied, even when a transport vehicle traveling to a charging point physically left the waiting point corresponding to the temporary storage area and picking area, a travel command to that waiting point was not assigned to another transport vehicle. As a result, the waiting time for other transport vehicles at that waiting point was long. In the second case study, where the transport system described above was applied, the total time for transporting goods throughout the factory was reduced by approximately 20% compared to the conventional system. Therefore, by having the waiting vehicle control unit detect the departure of a transport vehicle based on the travel plan to the charging point and pre-assign travel commands or transport commands to other transport vehicles, the waiting time for transport vehicles can be significantly reduced, dramatically improving the transport efficiency in factories where the transport system is introduced.

[0070] Although embodiments have been described above, one aspect of the present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention.

[0071] In the above embodiment, when a transport command to transport goods L from the first transport station 43 to the second transport station 44 is assigned to the transport vehicle 30, the standby vehicle control unit 62 may determine the departure of the transport vehicle 30 from the second standby point 52 corresponding to the second transport station 44 based on the transport command and the charge level of the transport vehicle 30. Similarly, when a transport command to transport goods L from the second transport station 44 to the third transport station 45 is assigned to the transport vehicle 30, the standby vehicle control unit 62 may determine the departure of the transport vehicle 30 from the third standby point 53 corresponding to the third transport station 45 based on the transport command and the charge level of the transport vehicle 30.

[0072] As an example, the standby vehicle control unit 62 predicts, based on the charge level of the transport vehicle 30 received from the transport vehicle controller 33, whether the charge level of the transport vehicle 30 to which a transport command has been assigned will fall below a threshold immediately after the completion of the transport command (immediately after the item L is transferred to the second transfer station 44). If it is predicted that the charge level of the transport vehicle 30 immediately after the completion of the transport command will fall below the threshold, the standby vehicle control unit 62 can determine that the transport vehicle 30 will travel to the charging station 42 immediately after the completion of the transport command, and thus the standby vehicle control unit 62 recognizes the departure of the transport vehicle 30 from the second waiting point 52. Based on the departure of the transport vehicle 30 from the second waiting point 52, the standby vehicle control unit 62 assigns a travel command to the second waiting point 52 to another transport vehicle 30. In this way, when a transport vehicle 30 transports item L to the second transfer station 44, it is possible to recognize that the transport vehicle 30 will be absent from the second waiting point 52 by using the transport command and the charge level of the transport vehicle 30.

[0073] In the above embodiment, the number of waiting points 50 provided for a transfer station 41 is not limited. Multiple waiting points 50 may be provided for one transfer station 41. One waiting point 50 may be provided for multiple transfer stations 41. Also, one waiting point 50 may be able to accommodate one transport vehicle 30, or multiple transport vehicles 30 may be able to accommodate one waiting point 50. Furthermore, the waiting points 50 may be provided in correspondence with a charging station 42. If the transport vehicle 30 is a tracked trolley, the waiting point 50 may be a waiting position on the track. If the transfer of goods L by the transport vehicle 30 occurs irregularly at a transfer station 41, the waiting point 50 corresponding to that transfer station 41 may be provided in an adjacent space rather than in the space below the mounting platform 41a.

[0074] In the above embodiment, when the standby vehicle control unit 62 detects that a transport vehicle 30 has left the standby point 50, it may simultaneously transmit the location information of the standby point 50 to all transport vehicles 30. In this case, the standby vehicle control unit 62 may wait for a reply from the transport vehicles 30 and assign a drive command to the standby point 50 to the transport vehicles 30 that have replied.

[0075] In the above embodiment, the manner in which the standby vehicle control unit 62 detects the departure of the transport vehicle 30 from the standby point 50 is not particularly limited. For example, the standby vehicle control unit 62 may detect the departure of the transport vehicle 30 from the standby point 50 corresponding to the transfer station 41 when it receives a transport request from the transfer station 41. Alternatively, for example, the standby vehicle control unit 62 may detect the departure of the transport vehicle 30 from the standby point 50 when a travel path search is initiated for the transport vehicle 30 waiting at the standby point 50. Alternatively, for example, the standby vehicle control unit 62 may detect the departure of the transport vehicle 30 from the standby point 50 when it receives a request for blocking control (control that prohibits other transport vehicles 30 from entering a predetermined area) from the transport vehicle 30 waiting at the standby point 50.

[0076] Each component in the above embodiments or modifications can be arbitrarily applied to each component in other embodiments or modifications. Some components in the above embodiments or modifications can be omitted as appropriate without departing from the spirit of one aspect of the present invention. The present invention is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0077] 1...Transportation system, 30...Transport vehicle (an example of an automated guided vehicle), 33...Transport vehicle controller, 40...Travel area, 41...Transfer station, 42...Charging station, 43...First transfer station, 44...Second transfer station, 45...Third transfer station, 46...Fourth transfer station, 50...Waiting point, 51...First waiting point, 52...Second waiting point, 53...Third waiting point, 60...System controller, L...Item (an example of an item to be transported).

Claims

1. Multiple automated guided vehicles capable of transporting objects from a transfer station, A controller for controlling multiple automated guided vehicles, The system includes a waiting point provided in correspondence with the transfer station, where the automated guided vehicle can wait, The aforementioned controller, The departure of the first automated guided vehicle from the aforementioned waiting point is detected, A transport system having a waiting vehicle control unit that, based on the departure of the first automated guided vehicle, assigns a travel command to a second automated guided vehicle, separate from the first automated guided vehicle, to the waiting point where the departure of the first automated guided vehicle was detected.

2. The aforementioned automated guided vehicle travels along a predetermined route, The transfer station and the waiting point are arranged along the route, The aforementioned waiting point is located near the corresponding transfer station. The transport system according to claim 1.

3. A plurality of transfer stations are provided, Multiple standby points are provided, and each of the multiple standby points is provided in accordance with each of the multiple transfer stations. The aforementioned controller, The transfer station and the standby point corresponding to the transfer station are stored in association with each other. The transport system according to claim 1 or 2, wherein for an automated guided vehicle that is present at or scheduled to be present at one of the multiple waiting points, a transport command to transport an object from a second transfer station separate from the first transfer station corresponding to that waiting point is not assigned.

4. The aforementioned standby vehicle control unit, A transport system according to any one of claims 1 to 3, which determines when an automated guided vehicle (AGV) leaves a waiting point based on its travel plan to a charging station for an AGV that is currently or is scheduled to be at the waiting point.

5. The aforementioned standby vehicle control unit, A transport system according to any one of claims 1 to 4, which determines when an automated guided vehicle leaves the waiting point based on the assignment of commands to the automated guided vehicle that is present at or scheduled to be present at the waiting point.

6. The aforementioned standby vehicle control unit, Determine the time required for other automated guided vehicles that have not been assigned a command to travel to the waiting point, and the time required for other automated guided vehicles that have been assigned a command to travel to the waiting point after the completion of the command. The transport system according to any one of claims 1 to 5, wherein, among a plurality of other automated guided vehicles, the one with the shortest travel time to the waiting point is assigned a command to travel to the waiting point.

7. The aforementioned automated guided vehicle transports the object to be transported from the first transfer station to the second transfer station, and then remains at the waiting point corresponding to the second transfer station. The aforementioned standby vehicle control unit, A transport system according to any one of claims 1 to 6, wherein when a transport command to transport an object to be transported to the second transport station is assigned to the automated guided vehicle, the system determines the departure of the automated guided vehicle from the waiting point corresponding to the second transport station based on the transport command and the charge level of the automated guided vehicle.

8. Multiple automated guided vehicles capable of transporting objects from a transfer station, A controller for controlling multiple automated guided vehicles, The system includes a waiting point provided in correspondence with the transfer station, where the automated guided vehicle can wait, The aforementioned controller, The system includes a waiting vehicle control unit that detects when an automated guided vehicle (AGV) leaves the waiting point and, based on the departure of the AGV, assigns a travel command to another AGV, separate from the AGV in question, to the waiting point. The aforementioned standby vehicle control unit, Determine the time required for other automated guided vehicles that have not been assigned a command to travel to the waiting point, and the time required for other automated guided vehicles that have been assigned a command to travel to the waiting point after the completion of the command. Among the multiple other automated guided vehicles, the command to travel to the waiting point is assigned to the other automated guided vehicle that has the shortest travel time to the waiting point. Conveyor system.

9. Multiple automated guided vehicles capable of transporting objects from a transfer station, A controller for controlling multiple automated guided vehicles, The system includes a waiting point provided in correspondence with the transfer station, where the automated guided vehicle can wait, The aforementioned controller, The system includes a waiting vehicle control unit that detects when an automated guided vehicle (AGV) leaves the waiting point and, based on the departure of the AGV, assigns a travel command to another AGV, separate from the AGV in question, to the waiting point. The aforementioned automated guided vehicle transports the object to be transported from the first transfer station to the second transfer station, and then remains at the waiting point corresponding to the second transfer station. The aforementioned standby vehicle control unit, When a transport command to transport an object to be transported to the second transfer station is assigned to the automated guided vehicle (AGV), the system determines the departure of the AGV from the waiting point corresponding to the second transfer station based on the transport command and the AGV's charge level. Conveyor system.

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