Transport system

Abstract

A transport system includes transport vehicles to travel along a track and transport a load, and a controller configured or programmed to control traveling of the transport vehicles, the track including a main track and first branch tracks branching off from the main track via branch points different from each other. The controller is configured or programmed to execute entry control to cause the transport vehicles to enter each of the first branch tracks and to cause the transport vehicles to enter any of the first branch tracks in a priority order according to entry information on entry states of the respective transport vehicles to the first branch tracks.

Description

BACKGROUND OF THE INVENTION1. Field of the Invention

[0001] The present invention relates to transport systems.2. Description of the Related Art

[0002] A transport system including a plurality of transport vehicles traveling along a track and a controller configured or programmed to control the traveling of the transport vehicles is known. As technology related to such a transport system, for example, Japanese Patent No. 6935846 describes a system in which transport vehicles are caused to preferentially enter a downstream branch track among a plurality of branch tracks of the track. In this transport system, the transport vehicles deliver a load to and from an unloading port provided along each of the branch tracks.SUMMARY OF THE INVENTION

[0003] In the transport system described above, the transport vehicles are caused to preferentially enter the downstream branch track, so if the number of transport vehicles that can enter each of the branch tracks becomes insufficient for some reason, the frequency of the transport vehicles entering an upstream branch track will decrease. In this case, the frequency of delivering the load to and from the unloading port provided along the upstream branch track will decrease. That is, the transportation of the load from a specific delivery port may be delayed, making smooth transportation of the load by the transport vehicles difficult.

[0004] Example embodiments of the present invention provide transport systems in each of which transport vehicles can smoothly transport loads.

[0005] A transport system according to an example embodiment of the present invention includes a plurality of transport vehicles to travel along a track and transport a load, and a controller configured or programmed to control traveling of the transport vehicles, the track including a first main track and a plurality of branch tracks branching off from the first main track via branch points different from each other, the controller being configured or programmed to execute entry control to cause the transport vehicles to enter each of the branch tracks from the first main track and to cause the transport vehicles to enter the branch tracks in a priority order according to entry information on entry states of the respective transport vehicles to the branch tracks.

[0006] This transport system causes the transport vehicles to enter the branch tracks from the first main track in the priority order according to the entry information on the entry states of the respective transport vehicles to the branch tracks. This can, for example, cause the transport vehicles to enter each of the branch tracks so as to prevent a situation in which there is always a shortage of the transport vehicles present on a specific branch track. Consequently, a decrease in the frequency of delivering the load to and from the delivery port provided along the specific branch track (a delay in the transportation of the load from a specific delivery port) can be prevented, and the transport vehicles can smoothly transport the load.

[0007] In a transport system according to an example embodiment of the present invention, the entry information may include information indicating the number of the transport vehicles present on each of the branch tracks. The entry control may cause the transport vehicles to preferentially enter a branch track with the fewest number of the transport vehicles present among the branch tracks based on the entry information. In this case, the situation in which there is always a shortage of the transport vehicles present on the specific branch track can be specifically prevented.

[0008] In a transport system according to an example embodiment of the present invention, the entry control, when there are a plurality of the branch tracks with the fewest number of the transport vehicles present, may cause the transport vehicles to enter the branch track corresponding to the branch point positioned most downstream of the first main track among the plurality of the branch tracks. This can cause the transport vehicles to enter each of the branch tracks more smoothly than a case in which the transport vehicles are caused to preferentially enter the branch track branching off upstream of the first main track among the plurality of the branch tracks.

[0009] In a transport system according to an example embodiment of the present invention, the entry information may include information on an entry branch track a first transport vehicle has entered. The entry control, when another branch point upstream adjacent to the branch point of the entry branch track is present in the first main track, may cause a second transport vehicle immediately following the first transport vehicle to enter the branch track corresponding to the another branch point and, when the another branch point is not present, may cause the second transport vehicle to enter the branch track corresponding to the branch point positioned most downstream of the first main track. In this case, the transport vehicles can be caused to enter each of the branch tracks equally.

[0010] In a transport system according to an example embodiment of the present invention, the entry information may include information indicating the number of the transport vehicles present on each of the branch tracks. The entry control may cause the transport vehicles to enter the branch track with the number of the transport vehicles present being less than a set number based on the entry information. The entry control, when the branch track with the number of the transport vehicles present being less than the set number is not present, may cause the transport vehicles to wait on the first main track. In this case, it is possible to avoid a situation in which the transport vehicles enter a specific branch track in a concentrated manner.

[0011] In a transport system according to an example embodiment of the present invention, the entry control, when after causing the transport vehicles to wait on the first main track, there arises a plurality of the branch tracks with the number of the transport vehicles present being less than the set number, may cause the transport vehicles that have been caused to wait to enter the branch track corresponding to the branch point positioned most downstream of the first main track among the plurality of the branch tracks. This can cause the transport vehicles to enter the branch track more smoothly than a case in which the transport vehicles are caused to preferentially enter the branch track branching off upstream of the first main track among the plurality of the branch tracks.

[0012] In a transport system according to an example embodiment of the present invention, the entry control starts entry of the transport vehicles that have been caused to wait on the first main track to at least any of the branch tracks based on a timing when the number of the transport vehicles present on the branch track corresponding to the branch point positioned most downstream has decreased. This can cause the transport vehicles to enter the branch track more smoothly than a case in which the transport vehicles are caused to preferentially enter the branch track branching off upstream of the first main track among the branch tracks.

[0013] In a transport system according to an example embodiment of the present invention, the track may include a second main track. The branch tracks may connect to the second main track via confluence points different from each other. The controller may be configured or programmed to execute departure control that causes the respective transport vehicles stopped at respective stop positions of the branch tracks to depart toward the second main track for each of the branch tracks. The entry control, at a timing when a transport destination of the transport vehicle has been determined, may increase the number of the transport vehicles present on the branch track corresponding to the transport destination by one. The departure control, at a timing when the transport vehicle on the branch track has been caused to depart, may decrease the number of the transport vehicles present on the branch track by one. In this case, the above action in which the transport vehicles can smoothly transport the load can be specifically achieved.

[0014] In a transport system according to an example embodiment of the present invention, the track may include a second main track and a backup branch track. The branch tracks may connect to the second main track via confluence points different from each other. The backup branch track may branch off from the first main track via a backup branch point as another branch point positioned downstream of the branch points and connect to the second main track via a backup confluence point as another confluence point positioned upstream of the confluence points. The entry control, when transfer of the load is impossible in at least any of a plurality of the branch tracks, may cause the transport vehicles scheduled to enter any of the plurality of the branch tracks in which the transfer of the load is impossible to enter the backup branch track instead of the plurality of the branch tracks. This can prevent a reduction in transport capacity by using the backup branch track even when the transfer of the load is impossible in at least any of the branch tracks.

[0015] In a transport system according to an example embodiment of the present invention, the track may include an auxiliary branch track. The auxiliary branch track may branch off from the second main track via an auxiliary branch point as a branch point positioned downstream of the confluence points and connect to the first main track via an auxiliary confluence point as a confluence point positioned upstream of the branch points. The controller may be configured or programmed to cause the transport vehicles that has been caused to enter the backup branch track to enter the auxiliary branch track. In this case, for example, even when an interface portion of the transport vehicles or objects to be transported gets into trouble on the branch tracks, and the transfer of the load is impossible, the reduction in the transport capacity of the transport system can be further prevented.

[0016] Example embodiments of the present invention can provide transport systems in each of which transport vehicles can smoothly transport loads.

[0017] The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a schematic plan view illustrating a transport system according to an example embodiment of the present invention.

[0019] FIG. 2 is a side view illustrating a transport vehicle of the transport system in FIG. 1.

[0020] FIG. 3 is a schematic plan view illustrating a first building side of the transport system in FIG. 1.

[0021] FIG. 4 is a schematic plan view illustrating an example of entry control in the transport system in FIG. 1.

[0022] FIG. 5 is a schematic plan view illustrating a continuation of FIG. 4.

[0023] FIG. 6 is a schematic plan view illustrating an example of the entry control in the transport system in FIG. 1.

[0024] FIG. 7 is a schematic plan view illustrating a continuation of FIG. 6.

[0025] FIG. 8 is a schematic plan view illustrating a first building side of a transport system according to a fourth example embodiment of the present invention.

[0026] FIG. 9 is a schematic plan view illustrating a first building side of a transport system according to a fifth example embodiment of the present invention.DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0027] Example embodiments will now be described with reference to the attached drawings. In description of the drawings, like or equivalent elements are designated by like reference signs, and duplicate description is omitted. The dimensional proportions in the drawings do not necessarily match those in the description.

[0028] The following describes a first example embodiment. As illustrated in FIG. 1, this transport system 1 according to the first example embodiment is a system configured to perform transportation between two points in which a transport source and a transport destination are patterned. The transport system 1 performs inter-building transportation, which performs delivery of loads between a first building F1 and a second building F2. The transport system 1 includes a plurality of transport vehicles10 and a controller 20. The transport vehicles 10 travel along a track 3 to transport loads. The transport vehicles 10 are configured to be capable of transferring loads. The transport vehicles 10 are Overhead Hoist Transports. The transport vehicles 10 are also referred to as, for example, vehicles (transport vehicles), overhead traveling vehicles (overhead transport carts), overhead traveling vehicles (overhead traveling carts), or traveling vehicles (traveling carts). The number of the transport vehicles 10 included in the transport system 1 is, for example, about 50 and varies depending on the amount of transport demand and a transport distance.

[0029] As illustrated in FIG. 2, the transport vehicle 10 includes a traveling cart 144, a power supply cart 145 configured to receive power supply from the track 3, a θ drive 147, and a lateral feeder 146 to laterally feed the lower portion thereof with respect to the track 3. The θ drive 147 turns a lifting and lowering driver 148 in a horizontal plane to control the attitude of a load L. The lifting and lowering driver 148 lifts and lowers a lifting and lowering platform 149, which grasps the load L, and delivers the load L to and from a delivery port 4. The lifting and lowering platform 149 grasps the portion of a flange 124 as the upper portion of the load L. The lateral feeder 146 and the drive 147 are not necessarily required to be provided. The load L is, for example, a container storing a plurality of semiconductor wafers, but it may also be a glass substrate, a general component, or the like.

[0030] The track 3 is laid on, for example, the ceiling or the like. The track 3 is supported by columns 141. The track 3 is a traveling path set in advance to cause the transport vehicles 10 to travel. The track 3 is a one-way traveling path. In other words, in the transport system 1, a traveling direction (a forward direction) of the transport vehicles 10 on the track 3 is set to one direction, and traveling in the opposite direction is prohibited. The track 3 has a closed track layout that is not affected from outside the track 3. In the following, the terms “upstream” and “downstream” correspond to “upstream” and “downstream,” respectively, in the traveling direction of the transport vehicles 10.

[0031] In the example illustrated in FIG. 1, the track 3 includes main tracks 31 and 32, four first branch tracks 33a, 33b, 33c, and 33d branching off from the main track 32 and joining the main track 31, and four second branch tracks 34a, 34b, 34c, and 34d branching off from the main track 31 and joining the main track 32. The main tracks 31 and 32 are tracks connecting between a first building F1 and a second building F2. The length of the main tracks 31 and 32 is, for example, 200 m. Between the first building F1 and the second building F2, the main tracks 31 and 32 are enclosed surrounded by a wall portion (not illustrated). The main track 31 and 32, the first branch tracks 33a to 33d, and the second branch tracks 34a to 34d define circling tracks to cause the transport vehicles 10 to travel in a circling manner.

[0032] The first branch tracks 33a to 33d are disposed inside the first building F1. The first branch tracks 33a to 33d extend in parallel or substantially parallel to each other. The first branch tracks 33a to 33d are provided in a comb-shaped arrangement between the main tracks 31 and 32 extending in parallel or substantially parallel to each other. The first branch tracks 33a to 33d are positioned upstream of the main track 31 (downstream of the main track 32) in this order. The second branch tracks 34a to 34d are disposed in the second building F2. The second branch tracks 34a to 34d extend in parallel or substantially parallel to each other. The second branch tracks 34a to 34d are provided in a comb-shaped arrangement between the main tracks 31 and 32 extending in parallel to each other. The second branch tracks 34a to 34d are positioned upstream of the main track 32 (downstream of the main track 31) in this order.

[0033] The following specifically describes the configuration and control of the transport system 1. In the following description, the configuration and control of the first building F1 will be described, and descriptions of the configuration and control of the second building F2 will be omitted as appropriate because they are similar.

[0034] As illustrated in FIG. 3, points at which the first branch tracks 33a to 33d join the main track 31 are confluence points 35a, 35b, 35c, and 35d. Each of the first branch tracks 33a to 33d connects to the main track 31 via each of the confluence points 35a, 35b, 35c, and 35d. That is, the track 3 includes the confluence points 35a to 35d, which are a plurality of confluence points spaced apart from each other on the main track 31. The main track 31 is joined from each of the first branch tracks 33a to 33d via the confluence points 35a, 35b, 35c, and 35d different from each other. For example, it is regarded that the portion of the track 3 downstream of the confluence point 35a is the main track 31, which is joined from the first branch track 33a upstream thereof. The first branch tracks 33a to 33d each connect to the main track 31 via the confluence points 35a to 35d different from each other. The confluence points 35a to 35d are separated from each other by a certain distance on the main track 31.

[0035] Points at which the first branch tracks 33a to 33d branch off from the main track 32 are branch points 36a, 36b, 36c, and 36d. Each of the first branch tracks 33a to 33d connects to the main track 32 via each of the branch points 36a, 36b, 36c, and 36d. In other words, the track 3 includes the branch points 36a to 36d, which are a plurality of branch points disposed spaced apart from each other on the main track 32. The main track 32 branches off to each of the first branch tracks 33a to 33d via the branch points 36a, 36b, 36c, and 36d different from each other. For example, it is regarded that the portion of the track 3 upstream of the branch point 36a is the main track 32, which branches off to the first branch track 33a downstream thereof. The first branch tracks 33a to 33d each connect to the main track 32 via the branch points 36a to 36d different from each other. The branch points 36a to 36d are separated from each other by a certain distance on the main track 32.

[0036] The “confluence point” is a point at which a branch track connects to a main track. The “confluence point” is a point at which the branch track leads to the main track. The “confluence point” is a connecting point of the branch track and the main track for allowing entry to the main track from the branch track. The “branch point” is a point at which the main track connects to the branch track. The “branch point” is a point at which the main track leads to the branch track. The “branch point” is a connecting point of the main track and the branch track for allowing entry to the branch track from the main track. In the example illustrated in FIG. 3, the main track 31 corresponds to a second main track, the main track 32 corresponds to a first main track, and the first branch tracks 33a to 33d correspond to branch tracks.

[0037] Each of the first branch tracks 33a to 33d has a stop position corresponding to the delivery port 4 for the transport vehicle 10 to deliver the load L. The delivery port 4 is disposed along each of the first branch tracks 33a to 33d. The delivery port 4 is provided, for example, on a conveyor (not illustrated) transporting the load L. The delivery port 4 includes an unloading port 41 and a loading port 42.

[0038] The unloading port 41 is a port for unloading the load L from the transport vehicle 10. At the unloading port 41, after the load L is placed, the load L is removed before the subsequent transport vehicle 10 arrives. The unloading port 41 is disposed upstream of the loading port 42 with a certain gap. In other words, the loading port 42 is disposed downstream of the unloading port 41 with a certain gap. The loading port 42 is a port for loading the load L onto the transport vehicle 10. The loading port 42 can bring in the load L into the port in a span of consecutive arrivals of the transport vehicles 10. As the unloading port 41 and the loading port 42, there are no particular limitations, and various known ports can be used or included.

[0039] As illustrated in FIG. 3, the controller 20 may be an electronic control unit including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like. The controller 20 can be configured as software in which, for example, a program stored in the ROM is loaded onto the RAM and is executed by the CPU. The controller 20 may be configured as hardware including electronic circuitry or the like. The controller 20 is configured or programmed to communicate with the transport vehicles 10 and control the traveling of the transport vehicles 10.

[0040] The controller 20 is configured or programmed to execute departure control to cause the transport vehicles 10 stopped at stop positions corresponding to the respective delivery ports 4 of the first branch tracks 33a to 33d (in this case, stop positions corresponding to the loading ports 42) to depart toward the main track 31 for each of the first branch tracks 33a to 33d. In the following, the stop position corresponding to the loading port 42 may also be referred to simply as the “stop position”. The upstream and downstream of the departure control correspond to the upstream and downstream of the main track 31, and the upstream and downstream of entry control correspond to the upstream and downstream of the main track 32.

[0041] The departure control causes the transport vehicle 10 stopped on the downstream first branch track 33 among the first branch tracks 33a to 33d to depart at the same time as or earlier than the transport vehicle 10 stopped on the upstream first branch track 33. Specifically, the departure control causes the transport vehicle 10 stopped on the first branch track 33d to depart at the same time as or earlier than the transport vehicle 10 stopped on the first branch track 33c. The departure control causes the transport vehicle 10 stopped on the first branch track 33c to depart at the same time as or earlier than the transport vehicle 10 stopped on the first branch track 33b. The departure control causes the transport vehicle 10 stopped on the first branch track 33b to depart at the same time as or earlier than the transport vehicle 10 stopped on the first branch track 33a.

[0042] More specifically, the departure control causes each of the stopped transport vehicles 10 to depart (forcedly depart) regardless of whether the load L is loaded at a timing repeated at a fixed cycle for each of the first branch tracks 33a to 33d. For example, the departure control starts counting down from a standard pitch time by a pitch timer in each of the first branch tracks 33a to 33d. When the count of the pitch timer reaches 0, the transport vehicle 10 stopped at the stop position is caused to depart, and the count of the pitch timer is reset to the standard pitch time. The counting down is then continued by the pitch timer. The standard pitch time may be a fixed value set in advance or a variable value. In the present example embodiment, the time axes of the pitch timers for the respective first branch tracks 33a to 33d are shifted so that the transport vehicle 10 stopped on the downstream first branch track 33 departs first.

[0043] The controller 20 is configured or programmed to execute the entry control that causes each of the transport vehicles 10 traveling on the main track 32 to successively enter each of the first branch tracks 33a to 33d from the main track 32 in the order from downstream to upstream. Specifically, in the entry control, the transport vehicle 10 is caused to enter the first branch track 33a, the next transport vehicle 10 is caused to enter the first branch track 33b, the next transport vehicle 10 is caused to enter the first branch track 33c, the next transport vehicle 10 is caused to enter the first branch track 33d, and then such entry of the transport vehicle 10 is repeated.

[0044] In the Entry Control, Transport Destination

[0045] determination control to determine (guide) a transport destination is performed for the transport vehicle 10 traveling through a specific section R upstream of the branch points 36a to 36d in the main track 32. The specific section R is a straight section close to the branch points 36a to 36d. The specific section R is not limited to a straight section, but may be a section including a curve, and may be various sections. The specific section R is not limited to a particular section so long as it is upstream of the branch points 36a to 36d. The transport destination determination control determines the delivery port 4 as the transport determination (in this case, the unloading port 41 of any of the first branch tracks 33a to 33d).

[0046] The controller 20 grasps the number (the entry number) of the transport vehicles 10 present on each of the first branch tracks 33a to 33d. Specifically, in the entry control, at a timing when the transport destination is determined by the transport destination determination control described above, the controller 20 increases (increments) the number of the transport vehicles 10 present on any of the first branch tracks 33a to 33d corresponding to the transport destination by one. When causing the transport vehicle 10 stopped at the stop position of any of the first branch tracks 33a to 33d to depart in the departure control, the controller 20 reduces (decrements) the number of the transport vehicles 10 present on any of the first branch tracks 33a to 33d by one at a timing of the departure.

[0047] Referring back to FIG. 1, the controller 20 is configured or programmed to execute virtual coupling control to perform the departure control and the entry control described above for each group of transport vehicles including a plurality of (four in this case) transport vehicles 10 corresponding to the number of the first branch tracks 33a to 33d. The controller 20 causes the transport vehicles 10 to travel along the circling tracks (the main tracks 31 and 32, the first branch tracks 33a to 33d, and the second branch tracks 34a to 34d) such that their circling distances or circling times are the same. For example, in the entry control, the controller 20 causes the transport vehicle 10 that has been caused to enter the first branch track 33d to enter the second branch track 34a, causes the transport vehicle 10 that has been caused to enter the first branch track 33c to enter the second branch track 34b, causes the transport vehicle 10 that has been caused to enter the first branch track 33b to enter the second branch track 34c, and causes the transport vehicle 10 that has been caused to enter the first branch track 33a to enter the second branch track 34d. In the entry control, the controller 20 causes the transport vehicle 10 that has been caused to enter the second branch track 34d to enter the first branch track 33a, causes the transport vehicle 10 that has been caused to enter the second branch track 34c to enter the first branch track 33b, causes the transport vehicle 10 that has been caused to enter the second branch track 34b to enter the first branch track 33c, and causes the transport vehicle 10 that has been caused to enter the second branch track 34a to enter the first branch track 33d.

[0048] Next, the following describes the entry control by the controller 20 in detail.

[0049] The entry control causes the transport vehicles 10 to enter the first branch tracks 33a to 33d from the main track 32 in a priority order according to entry information on entry states of the respective transport vehicles to the first branch tracks 33a to 33d. Specifically, the transport destination determination control included in the entry control determines the delivery port 4 to and from which the transport vehicles 10 deliver the load in the priority order according to the entry states. The entry control causes the transport vehicles 10 to enter any of the first branch tracks 33a to 33d corresponding to the delivery port 4 determined in the transport destination determination control.

[0050] As an example, the entry control acquires the entry information including information indicating the number of the transport vehicles 10 present on each of the first branch tracks 33a to 33d. The transport destination determination control, based on the acquired entry information, determines the delivery port 4 of the first branch track 33 with the fewest number of the transport vehicles 10 present among the first branch tracks 33a to 33d to be a transport destination of the transport vehicles 10. The entry control causes the transport vehicles 10 to enter the first branch track 33 corresponding to the determined transport destination. In other words, the entry control causes the transport vehicles 10 to enter the first branch track 33 with the fewest number of the transport vehicles 10 present among the first branch tracks 33a to 33d. The entry control, when there are a plurality of the first branch tracks 33 with the fewest number of the transport vehicles 10 present, determines the delivery port 4 of the first branch track 33 corresponding to the branch point 36 positioned most downstream of the main track 32 among the plurality of the first branch tracks 33 to be the transport destination of the transport vehicles 10. The entry control causes the transport vehicles 10 to enter the first branch track 33 corresponding to the determined transport destination. In other words, the entry control, when there are the plurality of the first branch tracks 33 with the fewest number of the transport vehicles 10 present, causes the transport vehicles 10 to enter the first branch track 33 corresponding to the branch point 36 positioned most downstream of the main track 32 among the plurality of the first branch tracks 33 among the first branch tracks 33a to 33d.

[0051] The transport destination determination control, when the first branch track 33 with the number of the transport vehicles 10 present being less than a set number is not present, does not determine the delivery port 4 as the transport destination. In this case, the entry control does not cause the transport vehicles 10 to enter the first branch tracks 33 but causes them to wait on the main track 32. The entry control starts entry of the transport vehicles 10 that have been caused to wait on the main track 32 to at least any of the first branch tracks 33 based on a timing when the number of the transport vehicles 10 present on the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream, has decreased (a timing when the count of the pitch timer has become 0). The entry control in this example starts the transport destination determination control for the transport vehicles 10 that have been caused to wait on the main track 32 with the decrement of the transport vehicles 10 present on the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream, as a trigger.

[0052] The set number is any number set by a user and is only required to be lower than or equal to the upper limit of the number of the transport vehicles 10 that can be present on each of the first branch tracks 33. For example, the set number may be one or two or more. The number of the transport vehicles 10 present on the first branch track 33a may not decrease at the timing when the count of the pitch timer has become 0. In this case too, the entry control may start entry of the transport vehicle 10 that have been caused to wait on the main track 32 to at least any of the first branch tracks 33.

[0053] FIG. 4 is a schematic plan view illustrating an example of the entry control in the transport system 1. FIG. 5 is a schematic plan view illustrating a continuation of FIG. 4. In the example illustrated in FIG. 4, transport vehicles 10a to 10c are traveling so as to approach a specific section R. Transport vehicles 10d to 10f are positioned at the loading ports 42 of the first branch tracks 33a to 33c, respectively. That is, the number of the transport vehicles 10 present on the first branch tracks 33a to 33c is one each, and the number of the transport vehicles 10 present on the first branch track 33d is zero.

[0054] In this situation illustrated in FIG. 4, for example, the following entry control is executed. First, when the transport vehicle 10a is positioned in the specific section R, the transport destination determination control determines the delivery port 4 of the first branch track 33d, which has the fewest number of the transport vehicles 10 present, that is, zero transport vehicle 10, to be the transport destination of the transport vehicle 10a. At this timing, the controller 20 increments the number of the transport vehicles 10 present on the first branch track 33d. The entry control causes the transport vehicle 10a to enter the first branch track 33d.

[0055] Subsequently, when the transport vehicle 10b is positioned in the specific section R, the transport destination determination control determines the delivery port 4 of the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, among the first branch tracks 33a to 33d, which have the number of the transport vehicles 10 present being one, to be the transport destination of the transport vehicle 10b. At this timing, the controller 20 increments the number of the transport vehicles 10 present on the first branch track 33a. £ The entry control causes the transport vehicle 10b to enter the first branch track 33a.

[0056] Finally, when the transport vehicle 10c is positioned in the specific section R, the transport destination determination control determines the delivery port 4 of the first branch track 33b corresponding to the branch point 36b, which is positioned most downstream of the main track 32, among the first branch tracks 33b to 33d, which have the fewest number of the transport vehicles 10 present, that is, one transport vehicle 10, to be the transport destination of the transport vehicle 10c. At this timing, the controller 20 increments the number of the transport vehicles 10 present on the first branch track 33b. The entry control causes the transport vehicle 10c to enter the first branch track 33b. Consequently, as illustrated in FIG. 5, the transport vehicle 10a is caused to enter the first branch track 33d, the transport vehicle 10b is caused to enter the first branch track 33a, and the transport vehicle 10c is caused to enter the first branch track 33b.

[0057] FIG. 6 is another schematic plan view for illustrating an example of the entry control. FIG. 7 is a schematic plan view illustrating a continuation of FIG. 6. In the example illustrated in FIG. 6, the transport vehicles 10a to 10c are traveling within the specific section R so as to approach a plurality of branch points 36. A plurality of transport vehicles 10 are positioned at all the respective unloading ports 41 and loading ports 42 of the first branch tracks 33a to 33d. In other words, the number of the transport vehicles 10 present on the first branch tracks 33a to 33d is two each, for example.

[0058] In this situation illustrated in FIG. 6, for example, when the set number is two, the following entry control is executed. First, each number of the transport vehicles 10 present on each of the first branch tracks 33a to 33d is the same number as the set number, and the transport destination determination control does not determine the transport destination of the transport vehicle 10a. The entry control, for example, when the transport vehicle 10a approaches the end of the specific section R, decelerates the transport vehicle 10a and causes the transport vehicle 10a to wait on the main track 32.

[0059] Then, as illustrated in FIG. 7, by the departure control, the transport vehicles 10 present on each of the first branch tracks 33a to 33d depart one by one in sequence. The entry control determines the transport destination for the transport vehicle 10a by the transport destination determination control at a timing when the number of the transport vehicles 10 present on the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream, has decreased. Consequently, the transport destination determination control determines the delivery port 4 of the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, among the first branch tracks 33a to 33d, which have the fewest number, which is one, of the transport vehicles 10 present, to be the transport destination of the transport vehicle 10a. At this timing, the controller 20 increments the number of the transport vehicles 10 present on the first branch track 33a. The entry control causes the transport vehicle 10a to enter the first branch track 33a.

[0060] The transport destination determination control determines the transport destination of the transport vehicle 10b following the transport vehicle 10a to be the delivery port 4 of the first branch track 33b. The entry control causes the transport vehicle 10b to enter the first branch track 33b. The transport destination determination control determines the transport destination of the transport vehicle 10c following the transport vehicle 10b to be the delivery port 4 of the first branch track 33c. The entry control causes the transport vehicle 10c to enter the first branch track 33c.

[0061] As described above, the transport system 1 causes the transport vehicles 10 to enter the first branch tracks 33 in the priority order according to the entry information on the entry states of the respective transport vehicles 10 to the first branch tracks 33. This can, for example, cause the transport vehicles 10 to enter each of the first branch tracks 33 so as to prevent a situation in which there is always a shortage of the transport vehicles 10 present on a specific first branch track 33. Consequently, a decrease in the frequency of delivering the load to and from the delivery port 4 provided along the specific first branch track 33 (a delay in the transportation of the load from the specific delivery port 4) can be prevented, and the transport vehicles 10 can smoothly transport the load.

[0062] In the transport system 1, the entry information includes the information indicating the number of the transport vehicles 10 present on each of the first branch tracks 33. The entry control causes the transport vehicles 10 to enter the first branch track 33 with the fewest number of the transport vehicles 10 present among the first branch tracks 33 based on the entry information. In this case, the situation in which there is always a shortage of the transport vehicles 10 present on the specific first branch track 33 can be specifically prevented.

[0063] In the transport system 1, the entry control, when there are the plurality of the first branch tracks 33 with the fewest number of the transport vehicles 10 present, causes the transport vehicles 10 to enter the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, among the plurality of the first branch tracks 33. This can cause the transport vehicles 10 to enter each of the branch tracks more smoothly than a case in which the transport vehicles 10 are caused to preferentially enter the first branch track 33 branching off upstream of the main track 32 among the plurality of the first branch tracks 33.

[0064] Specifically, compared to a case in which the transport vehicles 10 are caused to enter the first branch track 33 corresponding to the branch point 36 positioned upstream of the main track 32 among the first branch tracks 33, the transport vehicle 10 is prevented from hindering the traveling of another transport vehicle 10 following the transport vehicle 10, and the occurrence of congestion is prevented. In the example illustrated in FIG. 4, trouble or the like may occur on the first branch track 33 which the transport vehicle 10b enters, and the transport vehicle 10b may not be able to enter. In this case, for example, when the transport vehicle 10b is caused to enter the first branch track 33d, which branches off upstream of the main track 32, if the transport vehicle 10b stops upstream of the branch point 36, the transport vehicle 10b hinders the transport vehicle 10c immediately following the transport vehicle 10b from entering the first branch tracks 33a to 33c, and congestion may occur on the main track 32. In contrast, in the present example embodiment, as illustrated in FIG. 5, the transport vehicle 10b is caused to enter the first branch track 33a, which branches off most downstream of the main track 32. This enables the transport vehicle 10b to wait near the branch point 36a, which is positioned most downstream, thus preventing the traveling of the transport vehicle 10c immediately following the transport vehicle 10b from being hindered. Consequently, the transport vehicle 10c can smoothly enter the first branch tracks 33b to 33d. From the above, the transport vehicles 10 can be caused to enter the first branch track 33 more smoothly, and besides the occurrence of congestion on the main track 32 can be prevented.

[0065] In the transport system 1, the entry control starts entry of the transport vehicles 10 that have been caused to wait on the main track 32 to at least any of the first branch tracks 33 based on the timing when the number of the transport vehicles 10 present on the first branch track 33 corresponding to the branch point 36 positioned most downstream has decreased. This can cause the transport vehicles 10 to enter the first branch track 33 more smoothly than a case in which the transport vehicles 10 are caused to preferentially enter the first branch track 33 branching off upstream of the main track 32 among the first branch tracks 33.

[0066] In the transport system 1, the track 3 includes the main track 31. The first branch tracks 33 connect to the main track 31 via the confluence points 35 different from each other. The controller 20 is configured or programmed to execute the departure control that causes the respective transport vehicles 10 stopped at the respective stop positions of the first branch tracks 33 to depart toward the main track 31 for each of the first branch tracks 33. The entry control, at the timing when the transport destination of the transport vehicle 10 has been determined, increases the number of the transport vehicles 10 present on the first branch track 33 corresponding to the transport destination by one. The departure control, at the timing when the transport vehicle 10 on the branch track 33 has been caused to depart, decreases the number of the transport vehicles 10 present on the first branch track 33 by one. In this case, the above action in which the transport vehicles 10 can smoothly transport the load can be specifically achieved.

[0067] Next, the following describes a second example embodiment. In the first example embodiment above, the entry control causes the transport vehicles 10 to enter the first branch track 33 with the fewest number of the transport vehicles 10 present among the first branch tracks 33a to 33d, but this is not limiting. In the entry control according to the second example embodiment, the respective delivery ports 4 of the first branch tracks 33a to 33d may be determined in order from downstream to upstream of the main track 32 (cyclically) to be the transport destination of the transport vehicles 10, and the transport vehicles 10 may be caused to sequentially enter the first branch track 33 of the determined transport destination.

[0068] More specifically, the entry control according to the second example embodiment may acquire entry information including information on the first branch track 33 (an entry branch track) the transport vehicle 10 (a first transport vehicle) enters. The transport destination determination control, based on the acquired entry information, when another branch point 36 upstream adjacent to the branch point 36 of the first branch track 33 that the transport vehicle 10 has entered is present in the main track 32, may determine the delivery port 4 of the first branch track 33 corresponding to the another branch point 36 as the transport destination of another transport vehicle 10 (a second transport vehicle) immediately following the transport vehicle 10. The entry control may cause the other transport vehicle 10 to enter the first branch track 33 of the determined transport destination. In other words, the entry control, when the another branch point 36 upstream adjacent to the branch point 36 of the first branch track 33 that the transport vehicle 10 has entered is present in the main track 32, may cause the other transport vehicle 10 to enter the first branch track 33 corresponding to the another branch point 36.

[0069] In addition, the transport destination determination control of the entry control according to the second example embodiment, when the another branch point 36 is not present, may determine the delivery port 4 of the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, to be the transport destination of the other transport vehicle 10. The entry control may cause the other transport vehicle 10 to enter the first branch track 33 of the determined transport destination. In other words, the entry control, when the another branch point 36 is not present, may cause the other transport vehicle 10 to enter the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32.

[0070] In this case, for example, if the situation illustrated in FIG. 4 is immediately after the transport vehicle 10f has entered the first branch track 33c, the following entry control according to the second example embodiment is executed. First, in the main track 32, another branch point 36d is upstream adjacent to the branch point 36c of the first branch track 33c the transport vehicle 10f has entered, and thus the transport destination determination control determines the delivery port 4 of the first branch track 33d corresponding to the another branch point 36d to be the transport destination of the transport vehicle 10a immediately following the transport vehicle 10f. The entry control causes the transport vehicle 10a to enter the first branch track 33d.

[0071] Next, in the main track 32, the branch point 36 is not present upstream of the branch point 36d of the first branch track 33d the transport vehicle 10a has entered, and thus the transport destination determination control determines the delivery port 4 of the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, to be the transport destination of the transport vehicle 10b. The entry control causes the transport vehicle 10b to enter the first branch track 33a.

[0072] Finally, in the main track 32, another branch point 36b is upstream adjacent to the branch point 36a of the first branch track 33a the transport vehicle 10b has entered, and thus the transport destination determination control determines the delivery port 4 of the first branch track 33b corresponding to the another branch point 36b to be the transport destination of the transport vehicle 10c immediately following the transport vehicle 10b. The entry control causes the transport vehicle 10c to enter the first branch track 33b.

[0073] Thus, when the entry control described above is executed, the transport vehicles 10 enter the first branch track 33a to 33d in this order, and the transport vehicle 10 enters the first branch track 33a immediately after the transport vehicle 10 has entered the first branch track 33d. As a result of the above, the transport vehicle 10a is caused to enter the first branch track 33d, the transport vehicle 10b is caused to enter the first branch track 33a, and the transport vehicle 10c is caused to enter the first branch track 33b.

[0074] The transport system 1 executing the entry control according to the second example embodiment can cause a plurality of transport vehicles 10 to enter each of the first branch tracks 33 equally. This prevents the number of the transport vehicles 10 departing from the first branch tracks 33a to 33d from being reduced, thus preventing the number of the transport vehicles 10 on the second branch tracks 34a to 34d from becoming insufficient. Consequently, a decrease in the frequency of delivering the load by the transport vehicles 10 to and from the delivery ports 4 provided along the second branch tracks 34a to 34d is prevented, and thus a reduction in transport capacity can be prevented.

[0075] Subsequently, the following describes a third example embodiment. The entry control according to the third example embodiment may cause the transport vehicles 10 to enter the first branch track 33 with the number of the transport vehicles 10 present being less than a set number based on the acquired entry information. More specifically, the transport destination determination control may determine the delivery port 4 of the first branch track 33 with the number of the transport vehicles 10 present being less than the set number to be the transport destination of the transport vehicles 10 based on the acquired entry information. The entry control may cause the transport vehicles 10 to enter the first branch track 33 of the determined transport destination.

[0076] In this case, for example, in the situation illustrated in FIG. 4, the following entry control according to the third example embodiment is executed. First, when the set number is one, the transport destination determination control determines the delivery port 4 of the first branch track 33d, which has the number of the transport vehicles 10 present being zero, to be the transport destination of the transport vehicle 10a. The entry control causes the transport vehicle 10a to enter the first branch track 33d. When the set number is two, the transport destination determination control determines any of the delivery ports 4 of the first branch tracks 33a to 33d with the number of the transport vehicles 10 present being one or less to be the transport destination of the transport vehicle 10a. The entry control causes the transport vehicle 10a to enter the first branch track 33 of the determined transport destination.

[0077] For example, the transport destination determination control of the entry control according to the third example embodiment, when after causing the transport vehicles 10 to wait on the main track 32, there arises a plurality of the first branch tracks 33 with the number of the transport vehicles 10 present being less than the set number, may determine the delivery port 4 of the first branch track 33 corresponding to the branch point 36 positioned most downstream of the main track 32 among the plurality of the first branch tracks 33 to be the transport destination of the transport vehicles 10 that have been caused to wait. The entry control may cause the transport vehicles 10 to enter the determined transport destination. In other words, the entry control, when after causing the transport vehicles 10 to wait on the main track 32, there arises the first branch tracks 33 with the number of the transport vehicles 10 present being less than the set number, may cause the transport vehicles 10 to enter the first branch track 33 corresponding to the branch point 36 positioned most downstream of the main track 32 among the plurality of the first branch tracks 33.

[0078] In this case, for example, in the situation illustrated in FIG. 7, the following entry control according to the third example embodiment is executed. First, the transport destination determination control determines the delivery port 4 of the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, among the first branch tracks 33a to 33d to be the transport destination of the transport vehicle 10a that have been caused to wait on the main track 32. The entry control causes the transport vehicle 10a to enter the determined transport destination.

[0079] In the entry control according to the third example embodiment, based on the entry information, the transport vehicles 10 are caused to enter the first branch track 33 with the number of the transport vehicles 10 present being less than the set number. The entry control, when the first branch track 33 with the number of the transport vehicles 10 present being less than the set number is not present, causes the transport vehicles 10 to wait on the main track 32. This can avoid a situation in which the transport vehicles 10 enter a specific first branch track 33 in a concentrated manner. In other words, the transport vehicles 10 that can enter or more are prevented from entering each of the first branch tracks 33, and thus the occurrence of congestion on the first branch track 33 can be prevented. Consequently, a reduction in a transport amount in the transport system can be prevented.

[0080] The entry control according to the third example embodiment, when after causing the transport vehicles 10 to wait on the main track 32, there arises the plurality of first branch tracks 33 with the number of the transport vehicles 10 present being less than the set number, causes the transport vehicles 10 that have been caused to wait to enter the first branch track 33a corresponding to the branch point 36a, which is positioned most downstream of the main track 32, among the plurality of the first branch tracks 33. This can cause the transport vehicles 10 to enter the first branch track 33 more smoothly than a case in which the transport vehicles 10 are caused to preferentially enter the first branch track 33 branching off upstream of the main track 32 among the plurality of the first branch tracks 33.

[0081] Subsequently, the following describes a fourth example embodiment. In the first example embodiment to the third example embodiment, the track 3 includes the main tracks 31 and 32, the first branch tracks 33, and the second branch tracks 34, but the configuration of the track 3 is not limited to a particular configuration. FIG. 8 is a schematic plan view illustrating a transport system 101 according to the fourth example embodiment. As illustrated in FIG. 8, the transport system 101 according to the fourth example embodiment has a track 103 instead of the track 3 (refer to FIG. 3). The track 103 includes the main tracks 31 and 32, the first branch tracks 33, the second branch tracks 34, and a backup branch track 133. The backup branch track 133 connects to the main track 32 via a backup branch point 136 as another branch point positioned downstream of the branch points 36a to 36d. The backup branch track 133 connects to the main track 31 via a backup confluence point 135 as another confluence point positioned upstream of the confluence points 35a to 35d. The main track 32 branches off to the backup branch track 133 via the backup branch point 136. For example, it is regarded that the portion of the track 103 upstream of the backup branch point 136 is the main track 32, which branches off to the backup branch track 133 downstream thereof.

[0082] In the transport system 101 according to the fourth example embodiment, the entry control, when the transfer of the load is impossible in at least any of the plurality of the first branch tracks 33, causes the transport vehicles 10 scheduled to enter any of the plurality of the first branch tracks 33 in which the transfer of the load is impossible to enter the backup branch track 133 instead of the plurality of the first branch tracks 33. This can prevent a reduction in transport capacity by using the backup branch track 133 even when the transfer of the load is impossible in at least any of the first branch tracks 33. Specifically, the occurrence of congestion due to the transport vehicles 10 scheduled to enter hindering the traveling of another following transport vehicle 10 can be prevented. The backup confluence point 135 is separate from the confluence point 35a by a certain distance. The backup branch point 136 is separate from the branch point 36a by a certain distance.

[0083] In the transport system 101 according to the fourth example embodiment, the delivery port 4 is disposed along the backup branch track 133. This enables the transfer of the load on the backup branch track 133, which can further prevent the reduction in transport capacity in the transport system 1.

[0084] Subsequently, the following describes a fifth example embodiment. FIG. 9 is a schematic plan view illustrating a transport system 201 according to the fifth example embodiment. As illustrated in FIG. 9, the transport system 201 according to the fifth example embodiment includes a track 203 instead of the track 3 (refer to FIG. 3). The track 203 includes the main tracks 31 and 32, the first branch tracks 33, the second branch tracks 34, the backup branch track 133, and an auxiliary branch track 237. The auxiliary branch track 237 connects to the main track 31 via an auxiliary branch point 236 as a branch point positioned downstream of the confluence points 35. That is, the main track 31 branches off to the auxiliary branch track 237 via the auxiliary branch point 236. The auxiliary branch track 237 connects to the main track 32 via an auxiliary confluence point 235 as a confluence point positioned upstream of the branch points 36.

[0085] In the transport system 201 according to the fifth example embodiment, the entry control may cause the transport vehicles 10 that has been caused to enter the backup branch track 133 to enter the auxiliary branch track 237. In this case, for example, even if the interface portion of the transport vehicles 10 or objects to be transported gets into trouble on the first branch tracks 33, and the transfer of the load is impossible, the reduction in transport capacity can be further prevented. If there is a bias between the main track 31 and the main track 32 in the number of the transport vehicles 10 present on each of the main tracks 31 and 32, the bias can be eliminated by causing the transport vehicles 10 that are not transporting the load L to enter the auxiliary branch track 237. The backup branch track 133 and the auxiliary branch track 237 described above may also be provided in the second building F2.

[0086] Although example embodiments have been described above, the present invention is not limited to the above-described example embodiments, and various modifications or combinations can be made within the scope not departing from the gist of the invention.

[0087] In the above example embodiments, the track 3 includes four first branch tracks 33a to 33d, but the number of the first branch tracks may be two, three, or five or more. Similarly, the track 3 includes four second branch tracks 34a to 34d, but the number of the second branch tracks may be two, three, or five or more.

[0088] In the above example embodiments, the departure control causes the transport vehicle 10 to forcedly depart at a fixed cycle regardless of whether the load L is loaded but may cause the transport vehicle 10 to depart on the condition that the load L is loaded. In the above example embodiments, the transport destination determination control to determine the transport destination of the transport vehicles 10 traveling in the specific section R is executed, but the transport destination determination control is not necessarily required to be executed, and the delivery port 4 as the transport destination may be determined at any timing. In the above example embodiments, the virtual coupling control to perform control for each group of transport vehicles including a plurality of transport vehicles 10 is performed, but the virtual coupling control is not necessarily required to be executed.

[0089] In the above example embodiments, in the entry control, when the transport vehicles 10 are caused to enter the first branch track 33 corresponding to the transport destination, trouble may occur on the first branch track 33, and the transport vehicles 10 cannot enter the first branch track 33 (the first branch track 33 may be down). In this case, the entry control may cause the transport vehicles 10 to enter the first branch track 33 corresponding to another branch point 36 upstream adjacent to the branch point 36 of the first branch track 33. When the branch point 36 of the first branch track 33 in which the trouble has occurred is the branch point 36 positioned most upstream of the main track 32, the transport vehicles 10 may be caused to wait on the main track 32.

[0090] Various shapes can be used for each component in the above-described example embodiments, not limited to the shapes described above. Each component in each example embodiment can be freely used for each component in other example embodiments. Some of the components in the above example embodiments can be omitted as appropriate to the extent not departing from the gist of example embodiments of the present invention.

[0091] While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Claims

1-10. (canceled)11. A transport system comprising:a plurality of transport vehicles to travel along a track and transport a load; anda controller configured or programmed to control traveling of the transport vehicles;the track including a first main track and a plurality of branch tracks branching off from the first main track via branch points different from each other;the controller being configured or programmed to execute entry control to cause the transport vehicles to enter each of the branch tracks from the first main track and to cause the transport vehicles to enter the branch tracks in a priority order according to entry information on entry states of the respective transport vehicles to the branch tracks.

12. The transport system according to claim 11, whereinthe entry information includes information indicating a number of the transport vehicles present on each of the branch tracks; andthe entry control causes the transport vehicles to preferentially enter a branch track with a fewest number of the transport vehicles present among the branch tracks based on the entry information.

13. The transport system according to claim 12, wherein the entry control, when there are a plurality of the branch tracks with the fewest number of the transport vehicles present, causes the transport vehicles to enter the branch track corresponding to the branch point positioned most downstream of the first main track among the plurality of the branch tracks.

14. The transport system according to claim 11, whereinthe entry information includes information on an entry branch track a first transport vehicle enters; andthe entry control, when another branch point upstream adjacent to the branch point of the entry branch track is present in the first main track, causes a second transport vehicle immediately following the first transport vehicle to enter the branch track corresponding to the another branch point and, when the another branch point is not present, causes the second transport vehicle to enter the branch track corresponding to the branch point positioned most downstream of the first main track.

15. The transport system according to claim 11, whereinthe entry information includes information indicating a number of the transport vehicles present on each of the branch tracks; andthe entry control causes the transport vehicles to enter the branch track with a number of the transport vehicles present being less than a set number based on the entry information, and, when the branch track with the number of the transport vehicles present being less than the set number is not present, causes the transport vehicles not to enter the branch tracks and to wait on the first main track.

16. The transport system according to claim 15, wherein the entry control, when after causing the transport vehicles to wait on the first main track, there arises a plurality of the branch tracks with the number of the transport vehicles present being less than the set number, causes the transport vehicles that have been caused to wait to enter the branch track corresponding to the branch point positioned most downstream of the first main track among the plurality of the branch tracks.

17. The transport system according to claim 15, wherein the entry control starts entry of the transport vehicles that have been caused to wait on the first main track to at least any of the branch tracks based on a timing when a number of the transport vehicles present on the branch track corresponding to the branch point positioned most downstream has decreased.

18. The transport system according to claim 12, whereinthe track includes a second main track;the branch tracks connect to the second main track via confluence points different from each other;the controller is configured or programmed to execute departure control to cause the respective transport vehicles stopped at respective stop positions of the branch tracks to depart toward the second main track for each of the branch tracks;the entry control, at a timing when a transport destination of the transport vehicle has been determined, increases a number of the transport vehicles present on the branch track corresponding to the transport destination by one; andthe departure control, at a timing when the transport vehicle on the branch track has been caused to depart, decreases the number of the transport vehicles present on the branch track by one.

19. The transport system according to claim 11, whereinthe track includes a second main track and a backup branch track;the branch tracks connect to the second main track via confluence points different from each other;the backup branch track branches off from the first main track via a backup branch point as another branch point positioned downstream of the branch points and connects to the second main track via a backup confluence point as another confluence point positioned upstream of the confluence points; andthe entry control, when transfer of the load is impossible in at least any of a plurality of the branch tracks, causes the transport vehicles scheduled to enter any of the plurality of the branch tracks in which the transfer of the load is impossible to enter the backup branch track instead of the plurality of the branch tracks.

20. The transport system according to claim 19, whereinthe track includes an auxiliary branch track;the auxiliary branch track branches off from the second main track via an auxiliary branch point as a branch point positioned downstream of the confluence points and connects to the first main track via an auxiliary confluence point as a confluence point positioned upstream of the branch points; andthe entry control causes the transport vehicles that have been caused to enter the backup branch track to enter the auxiliary branch track.

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