Transport system

Abstract

To provide a transport system capable of improving transport efficiency while suppressing congestion of luggage on a circulating transport device.SOLUTION: A transport system (1) includes a circular transport device (2), multiple rows of input transport devices (4) that input packages to the circular transport device, multiple rows of output transport devices (6) that receive packages from the circular transport device in a predetermined order, and a control device (8) that controls whether the package located at the head of the input transport device is input to the circular transport device or put on standby. The control device inputs, into the circular transport device, immediate shipment items, which are packages that can be delivered to the output transport device without traveling around the circular path on the circular transport device more than once when input to the circular transport device, among the packages located at the head of each input transport device, while selecting some of the non-immediate shipment items, which are packages other than the immediate shipment items, as priority packages and inputs these priority packages into the circular transport device, while making the other packages wait.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a conveyance system, and more particularly to a conveyance system that carries out loaded cargo in multiple lines in a predetermined order. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2021-95244 (Patent Document 1) describes a conveying system. This conveying system includes multiple loading devices that load luggage, a conveying device that transports the luggage on a one-way circular route, and a chute from which the luggage transported by the conveying device is dispensed. A controller performs sequence control and storage control, thereby controlling the luggage transported on the circular route by the conveying device to be dispensed to each chute in a predetermined order. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-95244 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conveying system described in Patent Document 1, all conveyed packages are loaded onto the conveying device's circular path in the order in which they were delivered. The order in which the packages are loaded onto the conveying device is different from the order in which the packages are dispensed into the chute. As a result, packages that are to be dispensed later into the chute must wait until they are ready to be dispensed, while being conveyed around the circular path by the conveying device multiple times until the packages that should be dispensed earlier are dispensed into the chute. This causes the problem of the conveying device becoming congested due to the packages waiting to be dispensed.

[0005] Meanwhile, unlike the conveying system described in Patent Document 1, there is also a known conveying system that, among the conveyed parcels, only those that are ready to be dispensed into a chute are inserted into the circular path of the conveying device. In such a conveying system, all parcels inserted into the circular path of the conveying device are ready to be dispensed into a chute, so the inserted parcels do not wait on the circular path and do not return to their original positions on the circular path. However, this type of conveying system has the problem that the parcels spend a long time waiting to be dispensed, reducing conveying efficiency. Furthermore, if there is a line of parcels that should be dispensed first behind the leading parcel waiting to be dispensed, a deadlock may occur, causing the conveying operation to stagnate.

[0006] Therefore, an object of the present invention is to provide a conveyance system that can improve conveyance efficiency while suppressing congestion of luggage on the circular conveyance device (circular route). [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a conveying system that carries out loaded parcels in multiple rows in a predetermined order, comprising: a circular conveying device that transports the parcels along a predetermined circular path; multiple rows of input conveying devices that transport the parcels in the order they were loaded and input them into the circular conveying device; multiple rows of output conveying devices that receive the parcels transported by the circular conveying devices in a predetermined order; and a control device that controls whether the parcel located at the front of the multiple rows of input conveying devices is input into the circular conveying device or put on standby.The control device is characterized in that, when the parcel located at the front of each input conveying device is input into the circular conveying device, it inputs into the circular conveying device immediately shipped parcels that can be delivered to the output conveying device without circling the circular path on the circular conveying device more than once, while selecting some of the non-immediately shipped parcels that are parcels other than the immediately shipped parcels as priority parcels and inputs these priority parcels into the circular conveying device, while allowing the other parcels to wait.

[0008] According to the present invention configured in this manner, while immediate shipment items are loaded onto the circular conveying device, some of the non-immediate shipment items other than the immediate shipment items are selected as priority items, and these priority items are loaded onto the circular conveying device, while the other items are made to wait.This makes it possible to effectively prevent deadlocks from occurring while preventing the circular conveying device from becoming congested with items, thereby improving conveying efficiency.

[0009] In the present invention, the control device preferably selects priority cargo based on the order in which cargo should be delivered to each output conveying device and the order in which cargo is being conveyed by each input conveying device.

[0010] According to the present invention configured in this manner, priority luggage is selected based on the order in which luggage should be transported to each output conveying device and the order in which luggage is being transported by each input conveying device, so that the transport status of each luggage can be accurately grasped and each luggage can be transported efficiently.

[0011] In the present invention, the control device preferably determines whether or not to select a non-immediate shipment item as a priority shipment based on the order of shipments in the output conveying device from which the non-immediate shipment item is to be dispensed and the order of shipments in other output conveying devices.

[0012] According to the present invention configured in this manner, for a certain non-immediate shipment item, priority shipments are selected taking into consideration not only the order of shipments on the output conveying device from which the non-immediate shipment item is dispensed, but also the order of shipments on output conveying devices other than the one from which the non-immediate shipment item is dispensed, thereby improving the transportation efficiency of the entire transportation system.

[0013] In the present invention, the control device preferably selects, as priority cargo, a non-immediate shipment item located at the head of the input conveying device that has a cargo item behind it that needs to be removed first.

[0014] According to the present invention configured in this manner, among the non-immediate shipment items located at the head of the input conveying device, the non-immediate shipment item that has a shipment behind it that needs to be discharged first is selected as the priority shipment, thereby reliably preventing the occurrence of deadlock.

[0015] In the present invention, the control device is preferably configured to select priority cargo using a directed graph model, and the control device selects priority cargo by executing the following steps: a graph creation step for creating a directed graph in which cargo being transported by the input transport device is arranged in the order in which it should be received by the output transport device; a directed edge addition step for adding a directed edge from a cargo located in front of an immediately shipped item on the input transport device to the immediately shipped item in the directed graph created in the graph creation step; a directed edge deletion step for checking, starting from the downstream side of the directed graph, whether there is a cargo located behind the non-immediately shipped item on the input transport device upstream of the non-immediately shipped item in the directed graph in which the directed edge has been deleted in the directed edge deletion step; and a priority cargo selection step for selecting priority cargo by tracing the directed graph upstream from which the directed edge has been deleted in the directed edge deletion step and selecting the cargo located most upstream as the priority cargo.

[0016] According to the present invention configured in this manner, priority luggage is selected using a directed graph model, so that priority luggage can be selected efficiently and reliably to avoid deadlock.

[0017] In the present invention, preferably, the control device represents the directed graph as an adjacency matrix in the graph creation step, and executes the directed edge addition step, the directed edge deletion step, and the priority baggage selection step by performing operations on this adjacency matrix.

[0018] According to the present invention configured in this manner, the directed graph is represented as an adjacency matrix, and the directed edge addition step, directed edge deletion step, and priority baggage selection step are performed by operations on this adjacency matrix, so that the directed graph can be processed easily and quickly by a computer. [Effects of the Invention]

[0019] According to the conveying system of the present invention, it is possible to improve conveying efficiency while suppressing congestion of packages on the circulating conveying device. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a block diagram illustrating an entire transport system according to an embodiment of the present invention. [Figure 2] 1 illustrates an example of packages being transported on an input conveyor of a transport system according to an embodiment of the present invention, and the order in which the packages are received. [Figure 3] FIG. 10 is a diagram illustrating an example of transport of luggage by a conventional transport system as a comparative example. [Figure 4] 10 is a flowchart showing a procedure for controlling input to a circular conveyor in the conveyance system according to the embodiment of the present invention. [Figure 5] FIG. 10 is a diagram illustrating the selection of immediate shipment items in the transport system according to the embodiment of the present invention. [Figure 6] 1 is a diagram illustrating the selection of priority parcels in a conveyance system according to an embodiment of the present invention, showing the reference numerals assigned to each parcel to be conveyed. [Figure 7] FIG. 10 is a diagram showing an example of a directed graph in which packages being transported by each input conveyor are arranged in the order in which they should be received by each output conveyor in a transport system according to an embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing an example of a process for selecting priority cargo in the conveyance system according to the embodiment of the present invention. [Figure 9] FIG. 10 is a diagram showing an example of a process for selecting priority cargo in the conveyance system according to the embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing an example of a process for selecting priority cargo in the conveyance system according to the embodiment of the present invention. [Figure 11] 10A and 10B are diagrams illustrating input control after a priority cargo is selected in the conveyance system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, a transport system according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing the entire conveyance system according to an embodiment of the present invention.

[0022] As shown in Fig. 1, a conveying system 1 according to an embodiment of the present invention includes a circular conveyor 2 which is a circular conveying device, an input conveyor 4 which is an input conveying device that inputs luggage onto the circular conveyor 2, an output conveyor 6 which is an output conveying device that receives luggage transported by the circular conveyor 2, and a control device 8 which controls the input of luggage from the input conveyor 4 onto the circular conveyor 2. The conveying system 1 of this embodiment is configured to transport the loaded luggage in multiple lines in a predetermined order.

[0023] The circular conveyor 2 is a belt conveyor configured to transport luggage along a predetermined circular path, and is configured to transport luggage input from multiple input conveyors 4 in order along the circular path. In this embodiment, a belt conveyor is used as the circular transport device, but any transport device that can transport luggage along a predetermined circular path, such as multiple transport vehicles that run along a predetermined circular path, can be used as the circular transport device.

[0024] The input conveyor 4 is a roller conveyor configured to transport packages in the order in which they are brought in and input them into the circular conveyor 2. In this embodiment, the input conveyor 4 is configured to sequentially transport packages brought in from the warehouse 10 to an input position adjacent to the track of the circular conveyor 2, and then input the packages into the circular conveyor 2 in response to a command signal from the control device 8. In the example shown in FIG. 1, four rows of input conveyors 4 are provided adjacent to the circular conveyor 2, allowing packages to be input into four input positions on the circular conveyor 2. In this embodiment, a roller conveyor is used as the input conveying device, but any conveying device capable of transporting packages and inputting them into the circular conveyor 2, such as a belt conveyor, can be used as the input conveying device.

[0025] The output conveyor 6 is a roller conveyor for receiving the parcels transported by the circular conveyor 2 in a predetermined order. In this embodiment, the output conveyor 6 is configured to receive the parcels transported by the circular conveyor 2 from a predetermined delivery position. In the example shown in FIG. 1, four rows of output conveyors 6 are provided adjacent to the circular conveyor 2, and parcels can be delivered to the output conveyor 6 from the four delivery positions of the circular conveyor 2. Parcels are then delivered from the circular conveyor 2 so that each output conveyor 6 receives the parcel in a predetermined order. In this embodiment, a roller conveyor is used as the output conveying device, but any conveying device that can receive the parcels transported by the circular conveyor 2 in a predetermined order, such as a belt conveyor or a chute (a free roller conveyor), can be used as the output conveying device.

[0026] The control device 8 is configured to control the input of packages from the multiple input conveyors 4 to the circular conveyor 2, and the discharge of packages from the circular conveyors 2 to the multiple output conveyors 6. In particular, the control device 8 is configured to control the input or waiting of the first package (the package located adjacent to the input position) transported by the multiple rows of input conveyors 4 onto the circular conveyor 2, so that the packages can be efficiently discharged to each output conveyor 6 in a predetermined order. Specifically, the control device 8 is composed of a microprocessor, memory, interface circuitry, and software for operating these components.

[0027] As described above, in the conveying system 1 of this embodiment, the carried-in packages are sequentially transported by the input conveyor 4 and are input to the circular conveyor 2 in accordance with a control signal from the control device 8. The packages input to the circular conveyor 2 are transported by the circular conveyor 2 to the output position for each output conveyor 6 and output to each output conveyor 6. This output to each output conveyor 6 is performed so that the packages are lined up in a predetermined order on each output conveyor 6. Therefore, even if a package should be output to a certain output conveyor 6, if the package that should be lined up before that package has not yet been output to that output conveyor 6, the package will not be output to the output conveyor 6 and will continue to circulate on the circular conveyor 2. The control device 8 controls the input of packages from the input conveyor 4 to the circular conveyor 2 so that the number of packages continuing to circulate on the circular conveyor 2 is reduced, improving conveyance efficiency.

[0028] Next, the control of the control device 8 for inputting packages from the input conveyor 4 to the circular conveyor 2 will be described with reference to FIGS. Fig. 2 is a schematic diagram for explaining transportation by the transportation system 1, and shows an example of packages being transported by the input conveyor 4 of the transportation system 1 and the order in which these packages are received. In the example shown in Fig. 2, the transportation system 1 has three input conveyors 4a, 4b, and 4c for inputting packages into the circular conveyor 2, and two output conveyors 6a and 6b for receiving packages from the circular conveyor 2. The order in which the packages are received by each of the output conveyors 6a and 6b is determined in advance.

[0029] In the example shown in FIG. 2, as indicated by phantom lines on the output conveyor, output conveyor 6a must receive packages in the order of A1, A2, ... A5, and output conveyor 6b must receive packages in the order of B1, B2, ... B4. Meanwhile, each input conveyor 4a, 4b, 4c receives packages in the order shown in FIG. 2. Here, the first package that output conveyor 6a should receive is A1, and the first package that output conveyor 6b should receive is B1, but neither is the first package carried by the input conveyor. Furthermore, because package A1 is located third on input conveyor 4c and package B1 is located second on input conveyor 4b, packages A1 and B1 cannot be placed on circular conveyor 2 unless the packages in front of them are placed on circular conveyor 2 first.

[0030] FIG. 3 is a diagram showing an example of transport of luggage by a conventional transport system as a comparative example. In the comparative example shown in Fig. 3, all of the packages carried by the input conveyors 4a, 4b, and 4c are sequentially loaded onto the circular conveyor 2, starting from the front. Therefore, the packages are loaded onto the circular conveyor 2 sequentially from loading positions P1, P2, and P3 on the input conveyors 4a, 4b, and 4c, and are lined up on the circular conveyor 2 and transported as shown in Fig. 3.

[0031] When packages are loaded as in this comparative example, no package is dispensed until package B1 being transported by circular conveyor 2 reaches dispense position E2 on output conveyor 6b. Therefore, packages A2, A3, B3, and B4 in front of package B1 make two or more revolutions on circular conveyor 2. After package B1 is dispensed onto output conveyor 6b, no package is dispensed until package A2 reaches dispense position E1 on output conveyor 6a. Therefore, packages A4, B2, and A5 in front of package A1 also make two or more revolutions on circular conveyor 2.

[0032] After that, packages A2 and A3, which have completed two revolutions on the circular conveyor 2, are delivered to the output conveyor 6a at delivery position E1, and package B2 is delivered to the output conveyor 6b at delivery position E2. By repeating this operation, all packages are eventually discharged to each output conveyor in a predetermined order. As in the comparative example shown in Figure 3, if all packages at the head of each input conveyor were placed onto the circular conveyor 2 in the order they were transported, many packages would continue to rotate on the circular conveyor 2 without being delivered. For this reason, it is necessary to increase the number of packages that can be loaded onto the circular conveyor 2, which would result in the circular conveyor 2 taking up a large amount of space.

[0033] Furthermore, some conventional conveyance systems only feed packages that are ready for receipt by the output conveyor onto the circular conveyor 2. In such conveyance systems, packages fed onto the circular conveyor 2 do not make more than one revolution, allowing the circular conveyor 2 to be made smaller. However, in the state illustrated in FIG. 2, the packages that can be received by the output conveyors 6a and 6b are packages A1 and B1, while the packages that can be fed from each input conveyor are packages A2, A3, and B3. This means that there are no packages available for feeding, and conveyance by the conveyance system stops. Therefore, in a conveyance system that only feeds packages that the output conveyor can receive onto the circular conveyor 2, measures are required to avoid such deadlock situations. Specifically, the order in which packages are placed on each input conveyor must be managed to prevent deadlock, which creates a problem of system complexity.

[0034] In contrast, in the conveying system 1 of this embodiment, parcels that can be delivered to the output conveyor 6 without traveling more than one revolution around the circular path on the circular conveyor 2 when they are loaded onto the circular conveyor 2 are treated as "immediate shipment items." Furthermore, among non-immediate shipment items other than the immediate shipment items, parcels that should be given priority for loading onto the circular conveyor 2 are treated as "priority parcels." The control device 8 controls each input conveyor 4 so that the immediate shipment items and priority parcels among the parcels located at the head of each input conveyor 4 are loaded onto the circular conveyor 2. In the example shown in FIG. 2 , parcels A1 and B1 correspond to immediate shipment items that can be delivered to the output conveyor 6 without traveling more than one revolution around the circular path on the circular conveyor 2. Additionally, the control device 8 selects some of the non-immediate shipment items as priority parcels and loads these priority parcels onto the circular conveyor 2, while the other parcels wait. As will be described later, in the example shown in Figure 2, among the parcels other than immediate shipment items (non-immediate shipment items), parcels B3, B4, and A4 are selected as priority parcels, and when they reach the front of each input conveyor 4, they are preferentially inserted into the circular conveyor 2. This makes it possible to reduce the number of parcels circulating on the circular conveyor 2 while avoiding deadlock.

[0035] Next, the input control onto the circular conveyor 2 by the control device 8 in the transport system according to the embodiment of the present invention will be described with reference to FIGS. 4 is a flowchart showing the procedure for controlling input of goods onto the circular conveyor 2 by the control device 8. In this embodiment, the flowchart shown in FIG. 4 is executed when a parcel is input from any of the input conveyors 4 and when a parcel is delivered to any of the output conveyors 6, but the present invention can also be configured so that the flowchart is executed for each of multiple parcels that are input or delivered.

[0036] First, in step S1 of Fig. 4, information about the packages lined up on each input conveyor 4 and information about the order in which the packages should be discharged to each output conveyor 6 (the order of the packages as shown in Fig. 2) are input to the control device 8. The order in which the packages are lined up on each input conveyor 4 can be determined by the order in which the packages are released from the warehouse 10, or by reading the IDs of the packages with a reading device such as a barcode reader (not shown) placed midway along each input conveyor 4. Next, in step S2, items for immediate shipment are selected from the packages lined up on each input conveyor 4. An example of the selection of items for immediate shipment by the control device 8 in step S2 will be described below with reference to FIG.

[0037] 5, similar to the example shown in FIG. 2, for each piece of luggage lined up on each input conveyor 4, the time it takes for that piece of luggage to reach reference point P and the time it takes for that piece of luggage to make a revolution on the circular conveyor 2 until it is discharged to the output conveyor 6 are shown. That is, for each piece of luggage, the time it takes to reach reference point P is shown as a circled number, and the time it takes for that piece of luggage to make a revolution on the circular conveyor 2 is shown as a squared number. In the example shown in FIG. 5, the input position closest to the output conveyor 6a (P1 in FIG. 3) is set as the reference point P. In addition, in the example shown in FIG. 5, the time it takes for the circular conveyor 2 to make one revolution is calculated as 40 seconds.

[0038] As shown in Figure 5, the time it takes for the package to reach reference point P, indicated by the circled values, is the shortest at 3 seconds for package A2, which is closest to reference point P, and the longest at 19 seconds for package A1, which is lined up at the back of output conveyor 6c, the farthest from reference point P. In other words, the time it takes for the package to reach reference point P, indicated by the circled values, is calculated by adding the time it takes for the package to be transported to the head of the input conveyor plus the time it takes for the package placed on circular conveyor 2 to be transported to reference point P on circular conveyor 2.

[0039] Next, the time required for a revolution on the circular conveyor 2, shown by the value enclosed in a square in Figure 5, is calculated based on the number of revolutions that must be made on the circular conveyor 2 before it is delivered to the output conveyor 6. In other words, since packages A1 and B1 are the first packages to be delivered to each output conveyor 6, when they are placed on the circular conveyor 2, they do not need to make more than one revolution on the circular conveyor 2 before they are delivered to the output conveyor 6, and so the value enclosed in the square is 0.

[0040] Furthermore, since package A2 is a package that takes 3 seconds (the circled number) to reach reference point P from input conveyor 4a, if package A2 were to be inserted immediately, it would reach reference point P before package A1, which takes 19 seconds to reach reference point P. Therefore, the time for one revolution of circular conveyor 2 (40 seconds) is added as the value in the square so that package A2 will arrive later than package A1 (more than 19 seconds). Next, package A3 is a package that takes 8 seconds (the circled number) to reach reference point P from input conveyor 4b, so if the time for one revolution of circular conveyor 2 (40 seconds) is added, package A3 will arrive later than package A2 (43 seconds). Therefore, the value in the square (40 seconds) is added to package A3.

[0041] Similarly, adding one revolution (40 seconds) of the circular conveyor 2 to package A4 results in 56 seconds, which is later than package A3 (48 seconds). Therefore, the value in the square (40 seconds) is also added to package A4. Next, adding 40 seconds, which is one revolution of the circular conveyor 2, to package A5 will cause package A5 to reach reference point P before package A4 (56 seconds), so another revolution is added, and the value in the square becomes 80 seconds, which is two revolutions. In the same way, the values ​​of the circles and squares can be determined for packages B1 to B4.

[0042] The control device 8 calculates the time for each item in this way, and classifies items with a value of 0 in the box as items ready for immediate shipment that can be delivered to the output conveyor 6 without making more than one revolution around the circular path on the circular conveyor 2. When this item for immediate shipment is transported to the front of the input conveyor 4 (a position adjacent to the circular conveyor 2), the control device 8 places it on the circular conveyor 2 without waiting. As described above, in the example shown in Figure 5, items A1 and B1 are considered to be items for immediate shipment.

[0043] 5, only packages A1 and B1 that should be delivered first to each output conveyor 6 are judged to be immediate shipment items, but depending on the arrangement of packages on each input conveyor 4, packages other than the package that should be delivered first to each output conveyor 6 may also be judged to be immediate shipment items (the value in the square box may be 0). Alternatively, the present invention may be configured so that the processing in the control device 8 is simplified and only the package that should be delivered first to each output conveyor 6 is deemed to be immediate shipment items.

[0044] Next, priority packages are selected from packages other than immediate shipment packages (non-immediate shipment packages) by processing steps S3 to S6 in the flowchart shown in Fig. 4. As will be described below with reference to Figs. 6 to 10, in this embodiment, priority packages are selected based on the order in which the packages should be discharged to each output conveyor 6 and the order in which the packages are being transported by each input conveyor 4.

[0045] In the explanation of Figure 6 and subsequent figures, to facilitate intuitive understanding, the reference numerals given to each package in Figure 2 have been renumbered as shown in Figure 6. That is, the packages on input conveyor 4a are numbered a11, a12, and a13, starting from the top, the packages on input conveyor 4b are numbered a21, a22, and a23, and the packages on input conveyor 4c are numbered a31, a32, and a33.

[0046] In this way, the number on the left after the symbol "a" indicates the number of the input conveyor on which the package is placed, and the number on the right indicates the order on the input conveyor on which the package is placed (for example, the first package on the second input conveyor 4b is a21). By reassigning the symbols in this way, the order in which the packages should be discharged onto output conveyor 6a (A1 to A5 in FIG. 2) can be rewritten as a33, a11, a21, a32, a23, and the order in which the packages should be discharged onto output conveyor 6b (B1 to B4 in FIG. 2) can be rewritten as a22, a13, a31, a12.

[0047] In this embodiment, the control device 8 uses a directed graph model to select priority items from among non-immediate shipment items. That is, a directed graph is created in the graph creation step of step S3 in the flowchart shown in FIG. FIG. 7 shows an example of a directed graph in which packages being transported by each input conveyor 4 are arranged in the order in which they should be received by each output conveyor 6. In other words, FIG. 7 shows the order in which each package should be delivered to the output conveyors 6a and 6b, as described above, connected by arrows. The directed graph in the upper part of FIG. 7 is a directed graph showing the order in which packages will be delivered to the output conveyor 6a, and the directed graph in the lower part is a directed graph showing the order in which packages will be delivered to the output conveyor 6b. Furthermore, among the packages shown in the directed graph, immediate delivery items (a33, a22) are marked with an *.

[0048] Next, as a directed edge addition step in step S4 of FIG. 4, as shown in FIG. 8, a directed edge is added from the parcel located in front of the immediately shipped item (parcel marked with *) on the input conveyor 4 to the immediately shipped item in the directed graph created as in FIG. 7. That is, in this directed edge addition step, a directed edge (arrow) is added from the parcel located in front of the immediately shipped item on the input conveyor 4 to the immediately shipped item. Since immediately shipped item a33 is placed third on the third input conveyor 4c (FIG. 6), an arrow is added from parcel a32, which is placed second on the third input conveyor 4c, to immediately shipped item a33. Similarly, since immediately shipped item a22 is placed second on the second input conveyor 4b, an arrow is added from parcel a21, which is placed at the head of the second input conveyor 4b, to immediately shipped item a22.

[0049] Next, as a directed edge deletion step in step S5 of Figure 4, in the directed graph of Figure 8 to which a directed edge has been added, as shown in Figure 9, for each non-immediately shipped item, starting from the downstream side of the directed graph, it is checked whether there is a package located behind that non-immediately shipped item on the input conveyor 4 upstream of that non-immediately shipped item in the directed graph, and if there is, the directed edge between that non-immediately shipped item and the package located immediately upstream is deleted. In other words, package a23, which is located at the most downstream side of the directed graph, is placed third on the second input conveyor 4b, so there is no package located behind it, and so no directed edge deletion is performed. Package a32, which is the next most downstream package after package a23, is placed second on the third input conveyor 4c. On the input conveyor 4c, package a33 is placed behind package a32, and package a33 is located upstream of package a32 in the directed graph, so the directed edge between package a32 and package a21, which is located immediately upstream, is deleted (the directed edge marked with a cross in Figure 9). Furthermore, this process is repeatedly performed for all non-immediately shipped items (packages not marked with an *).

[0050] That is, package a21, which is the next most downstream package after package a32, is placed at the beginning of the second input conveyor 4b. Packages a22 and a23 are placed behind package a21 on input conveyor 4b, but these packages are downstream of package a21 on the directed graph (a directed edge has been added from package a21 to package a22), so no directed edge is deleted. Package a11, which is the next most downstream package after package a21, is placed at the beginning of the first input conveyor 4a. Packages a12 and a13 are placed behind package a11 on input conveyor 4a, but these packages are downstream of package a11 on the directed graph, so no directed edge is deleted.

[0051] Furthermore, package a12 is placed in the second position on the first input conveyor 4a. Package a13 is placed behind package a12 on the input conveyor 4a, and package a13 is located upstream of package a12 in the directed graph, so the directed edge between package a12 and package a31, which is located immediately upstream, is deleted (the directed edge marked with a cross in Figure 9). Next, package a31 is placed at the beginning of the third input conveyor 4c. Packages a32 and a33 are placed behind package a31 on the input conveyor 4c, and package a32 is located upstream of package a31 in the directed graph, so the directed edge between package a31 and package a13, which is located immediately upstream, is deleted (the directed edge marked with a cross in Figure 9). Finally, package a13 is placed in the third position on the first input conveyor 4a. Therefore, since there is no package placed behind package a13 on input conveyor 4a, no directed edge is deleted.

[0052] In this way, the directed graph in which the directed edges have been deleted in the directed edge deletion step is rearranged to produce the directed graph shown in FIG. 10. Since the directed edges connecting the packages a31 and a12 have been deleted, they become independent directed graphs (with one node). In the priority package selection step in step S6 of FIG. 4, the control device 8 traces the directed graph from which the directed edges have been deleted as shown in FIG. 9 back upstream and selects the package located most upstream as the priority package. Therefore, in the example shown in FIG. 10, the control device 8 selects the packages a32, a31, and a12 located most upstream in the directed graph as the priority packages.

[0053] By this process, of the non-immediate shipping items positioned at the head of the input conveyor 4, those that have items that need to be dispensed first behind them are selected as priority items by the control device 8. That is, the control device 8 selects some of the non-immediate shipping items (items a32, a31, a12) as priority items, among the non-immediate shipping items (items other than packages a22 and a33), and places these priority items onto the circular conveyor 2, while causing the other items (items other than packages a22, a33, a32, a31, a12) to wait.

[0054] As described above, in this embodiment, the priority shipment is selected taking into consideration the order of shipments to be delivered to the output conveyors 6a and 6b. That is, the control device 8 determines whether to select a certain non-immediate shipment item (e.g., shipment a31) as a priority shipment based on the order of shipments on the output conveyor (output conveyor 6b) from which the non-immediate shipment item is to be delivered and the order of shipments on the other output conveyor (output conveyor 6a).

[0055] In the above explanation, the processing of the directed graph in steps S3 to S6 of Fig. 4 has been described as the actual graph rewriting processing, but it is known that the directed graph can be expressed as an adjacency matrix that shows the connection between the nodes (the order of each baggage). Therefore, the processing of the directed graph shown in Fig. 7 to Fig. 10 is realized by calculating the adjacency matrix in a microprocessor (not shown) provided in the control device 8. That is, in the graph creation step of step S3, the directed graph is expressed as an adjacency matrix, and the directed edge addition step of step S4, the directed edge deletion step of step S5, and the priority baggage selection step of step S6 are executed by calculating the adjacency matrix.

[0056] Next, with reference to FIG. 11, the input control by the control device 8 after the immediate shipment items and priority shipment items are set in step S7 of FIG. 4 will be described. As shown in Figure 11, by processing up to step S6 in Figure 4, among the packages being transported on each input conveyor 4, the control device 8 selects packages a22 and a33 marked with double circles as items for immediate shipment, and packages a32, a31, and a12 marked with single circles as priority packages.

[0057] 11, packages a11, a21, and a31 are positioned at the head of each input conveyor 4. None of these packages are immediately shipped and can be delivered to the output conveyor 6 without traveling around the circular route more than once, but because package a31 is a priority package, the control device 8 sends a control signal to the input conveyor 4c, causing package a31 to be placed on the circular conveyor 2.

[0058] After package a31 is placed onto the circular conveyor 2, packages a11, a21, and a32 will each be positioned at the head of each input conveyor 4. Of these packages, package a32 is a priority package, so the control device 8 sends a control signal to the input conveyor 4c, causing package a32 to be placed onto the circular conveyor 2. Furthermore, after package a32 is placed onto the circular conveyor 2, packages a11, a21, and a33 will each be positioned at the head of each input conveyor 4. Of these packages, package a33 is an item to be shipped immediately, so the control device 8 sends a control signal to the input conveyor 4c, causing package a33 to be placed onto the circular conveyor 2.

[0059] Next, after package a33 passes reference point P on circular conveyor 2, when the flowchart shown in Figure 4 is executed, package a11 is selected as an immediate shipment item that can be delivered to output conveyor 6 without making more than one revolution around the circular path, so control device 8 sends a control signal to input conveyor 4a to put package a11 onto circular conveyor 2. Furthermore, when package a11 passes reference point P on circular conveyor 2, package a21 becomes an immediate shipment item, so control device 8 sends a control signal to input conveyor 4b to put package a21 onto circular conveyor 2.

[0060] After this, packages a12 and a22 are positioned at the head of input conveyors 4a and 4b, respectively, and because these packages are priority packages and immediate shipment items, the control device 8 puts these packages onto the circular conveyor 2. Furthermore, when the remaining packages a13 and a23 become priority packages or immediate shipment items, respectively, the control device 8 puts these packages onto the circular conveyor 2. Through the above operations, it is possible to prevent deadlocks from occurring while suppressing the number of packages circulating on the circular conveyor 2, and to improve transport efficiency.

[0061] According to the conveying system 1 of the embodiment of the present invention, immediate shipment items are loaded onto the circular conveyor 2, while some of the non-immediate shipment items other than the immediate shipment items are selected as priority shipments, and these priority shipments are loaded onto the circular conveyor 2, while the other shipments are made to wait.This prevents the circular conveyor 2 from becoming congested with shipments, effectively preventing the occurrence of deadlocks, and improves conveying efficiency.

[0062] Furthermore, according to the conveying system 1 of this embodiment, priority luggage is selected based on the order in which luggage should be discharged onto each output conveyor 6a, 6b and the order in which luggage is being transported by each input conveyor 4a, 4b, 4c, so that the transport status of each luggage can be accurately grasped and each luggage can be transported efficiently.

[0063] Furthermore, according to the conveying system 1 of this embodiment, for a certain non-immediate shipment item, the priority shipment is selected taking into consideration not only the order of the shipments on the output conveyor (e.g., output conveyor 6a) from which the non-immediate shipment item is dispensed, but also the order of the shipments on an output conveyor (e.g., output conveyor 6b) other than the one from which the non-immediate shipment item is dispensed, thereby improving the conveying efficiency of the entire conveying system.

[0064] Furthermore, according to the conveying system 1 of this embodiment, among the non-immediate shipment items located at the front of the input conveyor 4, the non-immediate shipment items that have shipments behind them that need to be dispensed first are selected as priority shipments, thereby reliably preventing the occurrence of deadlocks.

[0065] Furthermore, according to the conveyance system 1 of this embodiment, priority cargo is selected using a directed graph model, so that priority cargo can be selected efficiently and reliably to avoid deadlock.

[0066] Furthermore, according to the conveying system 1 of this embodiment, the directed graph is represented as an adjacency matrix, and the directed edge addition step, directed edge deletion step, and priority luggage selection step are executed by performing operations on this adjacency matrix, so that the directed graph can be processed easily and quickly by a computer.

[0067] Although the embodiment of the present invention has been described above, various modifications can be made to the above-described embodiment. In particular, in the above-described embodiment, priority luggage is selected using a directed graph model, but the present invention can also be configured to select priority luggage using other calculation algorithms.

[0068] For example, a priority is set for each parcel according to the order in which parcels are to be delivered to each output conveyor, so that the earlier the parcel is delivered, the higher the priority. Then, for a parcel at the head of each input conveyor, an evaluation function value is calculated based on the priority of the parcels lined up behind the input conveyor. For example, an evaluation function is set so that the higher the priority of the parcels lined up behind the parcel, the larger the evaluation function value. Furthermore, the evaluation function values ​​for each parcel at the head of each input conveyor can be compared, and a predetermined number of parcels with large evaluation function values ​​can be designated as priority parcels. [Explanation of symbols]

[0069] 1. Transport system 2 Circular conveyor (circular transport device) 4 Input conveyor (input transport device) 6 Output conveyor (output transport device) 8 Control Device 10 Warehouse

Claims

1. A conveyance system that carries out loaded cargo in multiple rows in a predetermined order, a circular conveyance device that conveys luggage along a predetermined circular route; a plurality of input conveying devices that convey the packages in the order in which they are carried in and input them into the circular conveying device; a plurality of output conveying devices for receiving the packages conveyed by the circular conveying devices in a predetermined order; a control device that controls the input or standby of the leading piece of luggage conveyed by the plurality of rows of input conveying devices onto the circular conveying device; and The control device inputs immediately shipped items, which are parcels positioned at the front of the input conveying devices and which can be delivered to the output conveying device without circulating the circular path on the circular conveying device once or more when input to the circular conveying device, into the circular conveying device, while This conveying system is characterized in that some of the non-immediate shipment items, which are items other than the immediate shipment items, are selected as priority items, and these priority items are put into the circular conveying device, while the other items are kept on standby.

2. 2. The conveying system according to claim 1, wherein the control device selects the priority cargo based on the order in which cargo should be delivered to each of the output conveying devices and the order in which cargo is being conveyed by each of the input conveying devices.

3. 2. The conveying system according to claim 1, wherein the control device determines whether to select a non-immediate shipment item as the priority shipment based on the order of shipments in the output conveying device from which the non-immediate shipment item is to be dispensed and the order of shipments in other output conveying devices.

4. 2. The conveying system according to claim 1, wherein the control device selects as the priority cargo, among the non-immediate shipment items located at the head of the input conveying device, those non-immediate shipment items that have cargo behind them that needs to be removed first.

5. the controller is configured to select the priority load using a directed graph model; The control device includes: a graph creation step of creating a directed graph in which the packages being transported by the input transport device are arranged in the order in which they should be received by the output transport device; a directed edge addition step of adding a directed edge from a package located in front of the immediately shipped item on the input conveying device to the immediately shipped item in the directed graph created in the graph creation step; a directed edge deletion step of checking, in the directed graph to which the directed edge has been added in the directed edge addition step, whether or not there is a package located on the input conveying device upstream of the non-immediately shipped item in the directed graph, for each non-immediately shipped item, in order from the downstream side of the directed graph, and if there is, deleting the directed edge between the non-immediately shipped item and the package located immediately upstream; a priority baggage selection step of tracing the directed graph from which the directed edge has been deleted in the directed edge deletion step back upstream and selecting the baggage located most upstream as the priority baggage; 2. The conveying system according to claim 1, wherein the priority load is selected by executing the above.

6. 6. The transportation system according to claim 5, wherein the control device, in the graph creation step, represents the directed graph as an adjacency matrix, and executes the directed edge addition step, the directed edge deletion step, and the priority luggage selection step by performing operations on this adjacency matrix.

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