Conveying system

Abstract

This technology provides a method for specifying the target to be brought out from three or more movable shelves using a designated signal transmitted from a single communication device in a transport vehicle. [Solution] The movable shelf is movable between a transfer position where the article 100 is transferred by the transport vehicle 10 and a retracted position where it is moved away from the transfer position. The first communication device 20 transmits a transport signal to the second communication device 40, which includes a first signal and a second signal different from the first signal. The transport vehicle 10 specifies which movable shelf should be moved from the retracted position to the transfer position based on a combination of the voltage levels of the first signal and the voltage levels of the second signal. The voltage levels of the first signal and the second signal each include a high level which is above a predetermined value and a low level which is below a predetermined value.

Description

Technical Field

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

Background Art

[0002] There is known a storage device in which articles are transferred by a transport vehicle (see, for example, Patent Document 1). The storage device includes a plurality of movable shelves arranged in the vertical direction. The transport vehicle advances one movable shelf from the retracted position to the transfer position by communicating with the storage device. The transport vehicle transfers articles to the movable shelf that has advanced to the transfer position.

[0003] Normally, one movable shelf to be advanced from the retracted position to the transfer position (hereinafter referred to as "target for advancement") is designated by a signal (hereinafter referred to as "designation signal") transmitted from one communication device provided on the transport vehicle to the storage device. The designation signal transmitted from one communication device on the transport vehicle consists of two signals: a signal indicating whether to designate the first movable shelf as the target for advancement and a signal indicating whether to designate the second movable shelf as the target for advancement.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The movable shelf that can be designated using the above designation signal is either the first movable shelf or the second movable shelf. That is, conventionally, the target for advancement is designated from among two movable shelves by the designation signal of one communication device. Therefore, in order to designate the target for advancement from among three or more movable shelves, it is necessary to install two or more communication devices on the transport vehicle.

[0006] The present invention aims to provide a technology that allows a designated signal transmitted from a single communication device in a transport vehicle to specify an object to be brought out from three or more movable shelves. [Means for solving the problem]

[0007] A transport system according to an aspect of the present invention comprises a transport vehicle for transporting articles and a storage device on which articles are transferred by the transport vehicle, wherein the transport vehicle comprises a first communication device for communicating with the storage device in order to transfer articles, the storage device comprises a second communication device for communicating with the first communication device and three or more movable shelves for storing articles, each movable shelf being movable between a transfer position on which articles are transferred by the transport vehicle and a retracted position where it is moved away from the transfer position, the first communication device transmits a transport signal to the second communication device, which includes a first signal and a second signal different from the first signal, the transport vehicle designates which movable shelf should be moved from the retracted position to the transfer position by a combination of the voltage levels of the first signal and the voltage levels of the second signal, and the voltage levels of the first signal and the second signal each include a high level which is above a predetermined value and a low level which is below a predetermined value. [Effects of the Invention]

[0008] In the transport system according to an embodiment of the present invention, when transferring articles from a transport vehicle to a storage device, the transport vehicle designates a movable shelf to be advanced from a retracted position to a transfer position based on a combination of the voltage levels of a first signal and a second signal. As a result, the transport vehicle can designate one of three or more movable shelves to be advanced to the transfer position using a single communication device (first communication device).

[0009] In the transport system according to the above embodiment, each movable shelf may be suspended from the ceiling in an orderly fashion on both sides of the track on which the transport vehicle travels. This configuration reduces the floor space occupied by the storage device.

[0010] In the transport system according to the above embodiment, the storage device has four movable shelves, the first and second movable shelves of the four movable shelves may be suspended from the ceiling in an orderly fashion on one side of the track on which the transport vehicle travels, and the third and fourth movable shelves of the four movable shelves may be suspended from the ceiling in an orderly fashion on the other side of the track. This configuration makes it possible to reduce the floor area occupied by the storage device.

[0011] In the transport system according to the above embodiment, the storage device may include a first fixed shelf suspended above the first and second movable shelves, and a second fixed shelf suspended above the third and fourth movable shelves. The transport vehicle may include a holding part for holding articles, and a lateral transfer mechanism for moving the holding part laterally to above the first or second fixed shelf. With this configuration, the transport vehicle can transfer articles to the two fixed shelves in addition to the four movable shelves.

[0012] In the transport system according to the above embodiment, communication between the first communication device and the second communication device may be interlock communication in accordance with the SEMI E84 standard. Furthermore, in the transport system according to the above embodiment, the transport signal may further include a third signal different from the first and second signals, and the transport vehicle may specify the movable shelf to be advanced from the retracted position to the transfer position based on the combination of the voltage levels of the first signal and the second signal when the voltage level of the third signal is transitioned from a low level to a high level or from a high level to a low level. With such a configuration, it becomes clear at which timing the voltage levels of the first and second signals are used to specify the movable shelf, thereby preventing the incorrect movable shelf from being specified. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows the schematic configuration of the transport system according to this embodiment. [Figure 2] This is a schematic diagram of the transport vehicle according to this embodiment. [Figure 3] This is a view of the storage device according to this embodiment, seen from the left and right directions. [Figure 4] This is a view of the storage device according to this embodiment, as seen from the direction of travel. [Figure 5] This figure shows the combinations of voltage levels for the CS_0 signal and CS_1 signal according to this embodiment, and the target of advancement specified by those combinations. [Figure 6] This figure shows the changes in the signal state of transport information and storage information during the unloading operation according to this embodiment. [Figure 7] This figure shows the changes in the signal state of transport information and storage information during the load grasping operation according to this embodiment. [Figure 8] This figure shows the changes in the signal states of transport information and storage information during the teaching operation according to this embodiment. [Figure 9] This figure shows another example of the storage device according to this embodiment. [Figure 10] This figure shows another example of the storage device according to this embodiment. [Modes for carrying out the invention]

[0014] The present invention will be described below through embodiments, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. In addition, in the drawings, the same or similar parts are denoted by the same reference numerals, and redundant explanations may be omitted. Also, the shape and size of elements in the drawings may be exaggerated for clearer explanation.

[0015] The position and orientation of components may be explained by referring to the XYZ Cartesian coordinate system. In this XYZ Cartesian coordinate system, the X and Y directions are horizontal, and the Z direction is vertical.

[0016] FIG. 1 is a diagram showing a schematic configuration of a transport system HS according to the present embodiment. FIG. 2 is a schematic configuration diagram of a transport vehicle 10 according to the present embodiment. The transport system HS transfers the article 100 between a transport vehicle 10 that transports the article 100 and a movable shelf on which the article 100 can be placed.

[0017] As shown in FIG. 1, the transport system HS includes, for example, a transport vehicle 10, a first communication device 20, and a storage device 30.

[0018] The transport vehicle 10 is a transport vehicle that transports the article 100, and travels along a ceiling track R provided at a position higher than the floor surface, such as the ceiling of a clean room. The ceiling track R is suspended via a support column BR fixed to the ceiling. Hereinafter, a case where the transport vehicle 10 is a ceiling transport vehicle will be described as an example. However, the transport vehicle 10 is not limited to a ceiling transport vehicle, and any transport vehicle that transports the article 100 and transfers the article 100 may be used.

[0019] The transport vehicle 10 transports the article 100 in a state of being suspended in the accommodation space AS. The transport vehicle 10 is used, for example, for transporting the article 100 between a processing device and the storage device 30. In FIG. 2, the X direction is the traveling direction of the transport vehicle 10. Also, in FIG. 2, the Z direction is the vertical direction of the transport vehicle 10.

[0020] The processing device is, for example, a film forming device, a coater / developer, an exposure device, an etching device, etc., and performs various processes in the process of manufacturing a device (e.g., a semiconductor device). The container storage device is arranged, for example, on a transport path for transporting the article 100 and temporarily stores the article 100. The container storage device is arranged, for example, near the ceiling. The article 100 contains, for example, a wafer or a reticle used for manufacturing a semiconductor element. The article 100 is, for example, a FOUP (Front Opening Unified Pod), a SMIF Pod, or a reticle Pod whose interior can be purged.

[0021] As shown in Figure 2, the transport vehicle 10 includes, for example, a running section 2, a connecting section 3a, a support section 3b, a power receiving device 4, a main body section 5, a cover 6, and a vehicle control device 7.

[0022] The running unit 2 moves the transport vehicle 10 along the overhead track R. The running unit 2 includes, for example, wheels arranged to be in contact with the overhead track R and a running drive unit that drives the wheels. This running drive unit generates a driving force to move the transport vehicle 10. The running drive unit has, for example, a running motor such as a linear motor or a rotary motor. The running drive unit also has a rotary encoder or a linear encoder. The vehicle control device 7 controls the linear motor or rotary motor of the running drive unit based on detection results such as the rotation speed of the wheels detected by the rotary encoder or linear encoder.

[0023] The connecting portion 3a connects the running portion 2 and the support portion 3b. For example, one end of the connecting portion 3a is connected to the running portion 2, and the other end is connected to the support portion 3b. The support portion 3b is arranged along a horizontal plane and supports the main body portion 5.

[0024] The power receiving device 4 receives power from the contactless power supply equipment in a contactless manner. The power receiving device 4 is installed, for example, in the connecting section 3a. The contactless power supply method from the contactless power supply equipment to the power receiving device 4 can be any of the following methods: electromagnetic induction, magnetic field (electric field) resonance, electric field coupling, or electromagnetic wave. The power received by the power receiving device 4 is converted into DC power and supplied to the above-mentioned drive unit and main body 5.

[0025] The main body 5 is connected to the running section 2 via a connecting section 3a and moves along the ceiling track R together with the running section 2. The main body 5 includes, for example, a lateral transfer mechanism 11, a rotation mechanism 12, a lifting section 13, and a holding section 14.

[0026] The lateral transfer mechanism 11 extends the rotation mechanism 12, the lifting section 13, and the holding section 14 laterally relative to the direction of travel. The direction of travel of the main body 5 is the direction in which the transport vehicle 10 travels along the ceiling track R by the travel section 2, i.e., the ±X direction. Lateral relative to the direction of travel means the direction perpendicular to the direction of travel, i.e., the ±Y direction. The rotation mechanism 12 rotates the lifting section 13 in the horizontal plane.

[0027] The lifting unit 13 lowers or raises the holding unit 14 at a predetermined speed, or holds the holding unit 14 at a target height. The lifting unit 13 is, for example, mounted below the rotating mechanism 12. The holding unit 14 is suspended from the lifting unit 13 by a plurality of suspension members. The lifting unit 13 is, for example, a hoist, and lowers the holding unit 14 by extending the plurality of suspension members. The lifting unit 13 also raises the holding unit 14 by winding up the plurality of suspension members.

[0028] The holding part 14 holds the article 100. The holding part 14 holds the article 100 suspended by gripping the flange of the article 100, for example. The method by which the holding part 14 grips the article 100 is not particularly limited; it may grip the article 100 from above, or it may grip the article 100 by clamping it from the left and right. The holding part 14 is, for example, a chuck equipped with a plurality of jaws that can move horizontally. The holding part 14 moves the jaws downward from the flange by a driving force such as a motor. Then, as the holding part 14 rises due to the winding up of the suspension member by the lifting part 13, the holding part 14 holds the article 100 in a suspended state.

[0029] Covers 6 are provided on the ±X sides of the main body 5, and each cover 6 is fixed to a support part 3b and extends in the -Z direction from the support part 3b. The pair of covers 6 form a space in which the article 100 is housed, i.e., a storage space AS.

[0030] The vehicle control device 7 may include a processor such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit) and non-volatile or volatile semiconductor memory (e.g., RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory)). For example, the vehicle control device 7 may be a microcontroller such as an MCU.

[0031] The vehicle control device 7 controls various operations of the transport vehicle 10. The vehicle control device 7 controls the movement of the transport vehicle 10 by controlling the travel drive unit. The vehicle control device 7 controls the transfer of articles 100 to and from the storage device 30. The transfer of articles 100 means either or both of the following: unloading the articles 100 from the storage device 30 and / or grasping the articles 100 from the storage device 30.

[0032] The vehicle control device 7 controls the lateral movement of the lateral transfer mechanism 11 by controlling the drive unit (e.g., electric motor) provided on the lateral transfer mechanism 11. The vehicle control device 7 can control the position of the holding unit 14 by controlling the lifting unit 13 to control the winding and unwinding (lowering) of the suspension member. The vehicle control device 7 also controls the operation of the holding unit 14, causing the holding unit 14 to hold the article 100 or to release the article 100 from being held by the holding unit 14.

[0033] When transferring goods 100, wireless communication is conducted between the transport vehicle 10 and the storage device 30. The communication standard for wireless communication is not particularly limited, but for example, it is interlock communication in accordance with the SEMI E84 standard. Interlock communication is a communication that confirms the operation and status of the transport vehicle 10 and the storage device 30 and notifies each other of it in order to properly transfer goods 100. The vehicle control device 7 is connected to the first communication device 20 and performs interlock communication with the storage device 30 via the first communication device 20.

[0034] The first communication device 20 is installed on the transport vehicle 10. The first communication device 20 is electrically connected to the vehicle control device 7. The first communication device 20 communicates with the second communication device 40 and sends and receives information with the second communication device 40. The vehicle control device 7, for example, performs interlock communication with the second communication device 40 via the first communication device 20 in accordance with the SEMI E84 standard and transmits transport information, which is information related to the transfer of goods, to the storage device 30.

[0035] Figure 3 is a view of the storage device 30 according to this embodiment from the Y direction (left-right direction). Figure 4 is a view of the storage device 30 according to this embodiment from the X direction (travel direction).

[0036] The storage device 30 stores the article 100. The storage device 30 is, for example, a buffer where the article 100 is temporarily stored. For example, if the article 100 being transported by the transport vehicle 10 cannot be transferred to the intended transfer port because another article 100 is placed there, the article 100 is temporarily placed in the storage device 30. The transfer port is a loading area for transferring the article 100 to semiconductor processing equipment (not shown), such as a cleaning device, a film deposition device, a lithography device, an etching device, a heat treatment device, and a planarization device.

[0037] The storage device 30 comprises multiple shelves 50, a detection unit 45, a second communication device 40, and a storage control device 70.

[0038] The multiple shelves 50 are arranged in a vertical line. Each of the multiple shelves 50 has multiple mounting sections 60. When viewed from the direction of travel, the multiple shelves 50 are arranged on both sides of the ceiling track R, flanking the travel area, as shown in Figure 4. In other words, the multiple shelves 50 are arranged on both the left side (-Y side) and the right side (+Y side) of the travel area.

[0039] The mounting section 60 is arranged along the direction of travel on each shelf 50. The mounting section 60 is the part on which one item 100 is placed. That is, the mounting section 60 is the part that supports and holds one item 100 from below. In the example shown in Figure 3, the mounting section 60 is the part on the shelf 50 on which one item 100 is placed. A positioning member for positioning the item 100 may be placed on the upper surface of the mounting section 60. Also, the mounting section 60 is formed to be the same size as the item 100 or larger in size than the item 100 in a plan view, for example.

[0040] In the following description, a unit of a collection of mounting sections 60 arranged vertically is defined as a "chain," and a collection of mounting sections 60 in one chain may be collectively referred to as a shelf chain. When viewed from the direction of travel, the storage device 30 has multiple shelf chains arranged on both the left side (-Y side) and the right side (+Y side) of the travel area, along a direction perpendicular to the vertical direction (travel direction). For the purpose of distinguishing each of the multiple shelf chains, they may be referred to as the 1st chain, 2nd chain, 3rd chain, and 4th chain in the +X direction.

[0041] The storage device 30 illustrated in Figures 3 and 4 has three shelves 50 on both the left (-Y side) and right (+Y side) sides of the travel area. Each shelf 50 has four mounting sections 60. In other words, the storage device 30 has four rows of shelves arranged on each side along the travel direction. In each row illustrated in Figures 3 and 4, three mounting sections 60 are arranged vertically.

[0042] Furthermore, in the storage device 30 illustrated in Figures 3 and 4, of the three shelves 50, only the top shelf 50 is a fixed shelf, and the other shelves 50 are movable shelves. The movable shelves are shelves that can be moved to a transfer position where items 100 can be transferred. The transfer position corresponds to the position directly below the ceiling track R. The fixed shelves are fixed in the position shown in Figure 4 and cannot be moved to the transfer position. Note that the top shelf 50, which is the fixed shelf, may be referred to as the "first storage section 300," and the other shelves 50, which are the movable shelves, may be collectively referred to as the "second storage section 310."

[0043] The first storage unit 300 is suspended from the ceiling by suspension parts 41. Specifically, when viewed from the direction of travel, the uppermost shelf 50, which is an example of the first storage unit 300, is suspended from the ceiling on both sides of the travel area. The uppermost shelf 50 is fixed to the suspension parts 41 on both sides of the travel area and is immovable relative to the suspension parts 41. The suspension parts 41 are suspended from the ceiling C via mounting parts 42. The suspension parts 41 are arranged at equal intervals along the extending direction of the ceiling track R, for example.

[0044] Of the uppermost shelves 50, the shelf 50 located on one side of the ceiling track R is the first fixed shelf, and the shelf 50 located on the other side is the second fixed shelf.

[0045] The uppermost shelf 50, which is the first storage section 300, is provided with a fall prevention fence 43. The fall prevention fence 43 prevents the articles 100 from falling from the storage section 60. The fall prevention fence 43 is positioned on the left and right sides of the articles 100 placed on the storage section 60, for example, when viewed from the direction of travel. The fall prevention fence 43 extends along the ceiling track R.

[0046] When the transport vehicle 10 transfers (unloads or grasps) items 100 to the uppermost shelf 50, it uses the lateral transfer mechanism 11 to move the lifting section 13 and the holding section 14 laterally in the +Y or -Y direction, and the lifting section 13 to raise and lower the holding section 14. The transport vehicle 10 then controls the movement of the holding section 14 and unloads the items 100 to the designated mounting section 60, or grasps the items 100 that are already mounted on the mounting section 60, as specified by the higher-level controller.

[0047] The second storage section 310 is located below the first storage section 300. When viewed from the direction of travel, the second storage section 310 is located on either side or one side of the travel area. In the example shown in Figure 4, the movable shelves 50 that constitute the second storage section 310 are arranged in pairs facing each other across the lifting and lowering area S of the holding section 14. The lifting and lowering area S is the area in which the holding section 14 moves up and down when transferring an item 100 to the second storage section 310.

[0048] As described above, each shelf 50 of the second storage unit 310 is a movable shelf that can be moved to a transfer position where the items 100 can be transferred. Specifically, the movable shelf is movable between a transfer position where the items 100 are transferred by the transport vehicle 10 and a retracted position where it is moved away from the transfer position. The transfer position is set within the lifting area S.

[0049] Specifically, all shelves 50 shown in Figure 4 are in the retracted position. In Figure 4, the multiple shelves 50 located on the left side can be moved to a transfer position within the lifting area S by sliding each shelf 50 independently to the right (+Y direction). Also, in Figure 4, each of the multiple shelves 50 located on the right side can be moved to a transfer position within the lifting area S by sliding each shelf independently to the left (-Y direction).

[0050] When transferring items 100 in the storage device 30 as illustrated in Figures 3 and 4, one transport vehicle 10 is assigned to the storage device 30. In other words, the transfer of items 100 in the storage device 30 is not performed simultaneously by multiple transport vehicles 10, but by one transport vehicle 10. The drive source for the movement of each shelf is, for example, a motor, cylinder, etc., and is controlled by the storage control device 70.

[0051] Transferring items from the transport vehicle 10 to the second storage section 310 is performed by raising and lowering the holding section 14 relative to the placement section 60 of the shelf 50 that has advanced to the transfer position (lifting / lowering area S). In this embodiment, for the purpose of distinguishing each of the second storage sections 310, the left shelf 50 is referred to as shelf 50-1 and shelf 50-2 from the bottom, and the right shelf 50 is referred to as shelf 50-3 and shelf 50-4 from the bottom.

[0052] The detection unit 45 detects the presence or absence of an article 100 placed on the placement unit 60. For example, the detection unit 45 detects the presence or absence of an article 100 placed on each placement unit 60. The detection unit 45 is connected to the storage control device 70 and transmits the detection results to the storage control device 70. The detection unit 45 is equipped with, for example, either or both a Placement Sensor and a Presence Sensor for each placement unit 60. When an article 100 is placed on a placement unit 60, the detection results of both the Placement Sensor and the Presence Sensor for that placement unit 60 are ON.

[0053] The second communication device 40 can communicate with the first communication device 20. The second communication device 40 receives transport information from the first communication device 20 in interlock communication. That is, the transport vehicle 10 transmits transport information to the second communication device 40 via the first communication device 20. The storage device 30 receives the transport information transmitted from the transport vehicle 10 via the second communication device 40. The transport information includes a signal for identifying the movable shelf (target to be moved) to be moved from the retracted position to the transfer position, and signals indicating the start and completion of the transfer.

[0054] The second communication device 40 is installed on the overhead track R. There is a one-to-one correspondence between the second communication device 40 and the train. In the example shown in Figures 3 and 4, the storage device 30 has four trains along the direction of travel. Therefore, four second communication devices 40 are installed on the overhead track R.

[0055] Here, the stopping position T of the transport vehicle 10 is set corresponding to each of the multiple trains. This stopping position T is a stopping position on the overhead track R for transferring the article 100 between any of the multiple loading sections 60 in one train. In the example shown in Figures 3 and 4, four stopping positions T1 to T4 are set. The second communication device 40 is provided on the overhead track R in a one-to-one correspondence with each of the multiple stopping positions T1 to T4. For example, the second communication device 40 is provided on the overhead track R near each of the multiple stopping positions. In order to distinguish each of the multiple second communication devices 40, they may be referred to as second communication device 40a, second communication device 40b, second communication device 40c, and second communication device 40d in the +X direction.

[0056] When the transport vehicle 10 stops at one of the multiple stopping positions T1 to T4, it communicates with the second communication device 40 corresponding to that stopping position. That is, the first communication device 20 performs interlock communication only with the second communication device 40 among the multiple second communication devices 40 that is provided corresponding to the stopping position where the transport vehicle 10 has stopped. For example, the second communication device 40 provided corresponding to the stopping position where the transport vehicle 10 has stopped may be the second communication device 40 closest to that stopping position. For example, the second communication device 40 provided corresponding to the stopping position where the transport vehicle 10 has stopped is mounted in a position that allows infrared communication with the first communication device 20 mounted on the transport vehicle 10 when the transport vehicle 10 has stopped at that stopping position.

[0057] The first communication device 20 performs interlock communication only with the second communication device 40 that corresponds to the stopping position where the transport vehicle 10 has stopped, out of the multiple second communication devices 40. For example, in Figure 3, when the transport vehicle 10 stops at stopping position T1, the first communication device 20 performs interlock communication only with the second communication device 40a.

[0058] The second communication device 40 transmits storage information to the first communication device 20 during interlock communication. That is, the storage device 30 transmits storage information to the first communication device 20 via the second communication device 40. The storage information includes, for example, information such as a transfer request or whether the item to be moved has reached the transfer position. The transport vehicle 10 receives the storage information transmitted from the storage device 30 via the first communication device 20.

[0059] The transport information and storage information according to this embodiment will be described below. The transport information includes at least a CS_0 signal and a CS_1 signal. The transport information may further include a VALID signal, a TR_REQ signal, a BUSY signal, and a COMPT signal. The CS_0 signal is an example of a first signal. The CS_1 signal is an example of a second signal. The VALID signal is an example of a third signal.

[0060] The CS_0 and CS_1 signals are used to specify which movable shelf should be moved from the retracted position to the transfer position. In the example shown in Figure 3, the storage device has four movable shelves. Therefore, in the storage device shown in Figure 3, the CS_0 and CS_1 signals are used to specify which of the four movable shelves should be moved.

[0061] For example, the target for advancement is specified by a combination of the voltage levels of the CS_0 signal and the CS_1 signal. That is, the vehicle control device 7 specifies one of the four movable shelves (shelf 50-1, shelf 50-2, shelf 50-3, shelf 50-4) as the target for advancement by controlling the combination of the voltage levels of the CS_0 signal and the CS_1 signal in the transport information transmitted to the second communication device 40 via the first communication device 20.

[0062] The voltage levels of the CS_0 and CS_1 signals each include a high level which is above a predetermined value and a low level which is below that predetermined value. Note that a low level being below the predetermined value includes a low level which is below a threshold value lower than that predetermined value. Figure 5 shows the combinations of voltage levels for the CS_0 and CS_1 signals according to this embodiment, and the target of advancement specified by those combinations. In the following description, a high signal voltage level may be referred to as "ON," and a low signal voltage level may be referred to as "OFF."

[0063] In the example shown in Figure 5, the vehicle control device 7 can, for example, designate shelf 50-1 as the target for access by controlling the voltage level of the CS_0 signal to "OFF" and the voltage level of the CS_1 signal to "OFF". The vehicle control device 7 can, for example, designate shelf 50-2 as the target for access by controlling the voltage level of the CS_0 signal to "ON" and the voltage level of the CS_1 signal to "OFF". The vehicle control device 7 can, for example, designate shelf 50-3 as the target for access by controlling the voltage level of the CS_0 signal to "OFF" and the voltage level of the CS_1 signal to "ON". The vehicle control device 7 can, for example, designate shelf 50-4 as the target for access by controlling the voltage level of the CS_0 signal to "ON" and the voltage level of the CS_1 signal to "ON".

[0064] The VALID signal indicates whether or not the item 100 can be transferred to the storage device 30. When the VALID signal is "ON", it indicates that the item 100 can be transferred. When the VALID signal is "OFF", it indicates that the item 100 cannot be transferred.

[0065] The TR_REQ signal is a signal used to request the storage device 30 to move the item to be moved to the transfer position. The vehicle control device 7 controls the TR_REQ signal to "ON" when, for example, the transport vehicle 10 has finished moving and is ready for the transfer to move the item 100 to and from the storage device 30. In this way, the vehicle control device 7 instructs the storage device 30 to move the item to be moved to the transfer position. Being ready for the transfer means, for example, when the transport vehicle 10 has stopped at the stopping position T and the holding unit 14 can be lowered for the transfer of the item 100. The vehicle control device 7 may keep the TR_REQ signal "ON" until the transfer is complete.

[0066] The BUSY signal indicates whether or not the transport vehicle 10 is performing a transfer operation of the item 100. When the BUSY signal is "ON", it indicates that the transport vehicle 10 is performing a transfer operation of the item 100. When the BUSY signal is "OFF", it indicates that the transport vehicle 10 is not performing a transfer operation of the item 100. The transfer operation may include all of the following: lowering the holding unit 14, the transport vehicle 10 unloading or grasping the item 100 from the shelf 50 (target for advancement) at the transfer position, and raising the holding unit 14 after unloading or grasping.

[0067] The COMPT signal indicates whether the transfer of the goods 100 by the transport vehicle 10 has been completed. When the COMPT signal is "ON", it indicates that the transfer of the goods 100 by the transport vehicle 10 has been completed. When the COMPT signal is "OFF", it indicates that the transfer of the goods 100 by the transport vehicle 10 has not been completed. For example, if the BUSY signal changes from "ON" to "OFF", the vehicle control device 7 controls the COMPT signal from "OFF" to "ON", informing the storage device 30 that the transfer operation of the goods 100 by the transport vehicle 10 has been completed.

[0068] Storage information is information transmitted from the storage device 30 to the transport vehicle 10. The storage information includes a transfer request signal and a READY signal.

[0069] The transfer request signal is a signal used to request the storage device 30 to perform a transfer. When the transfer request signal is "ON", it indicates that a transfer request has been made. In addition, to distinguish between unloading and grasping of the goods 100, the transfer request signal when unloading is sometimes called the L_REQ signal, and the transfer request signal when grasping is sometimes called the U_REQ signal.

[0070] The READY signal indicates whether the movable shelf to be moved has moved to the transfer position. When the READY signal is "ON", it indicates that the movable shelf to be moved is in the transfer position. When the READY signal is "OFF", it indicates that the movable shelf to be moved is not in the transfer position. Therefore, when the READY signal transitions from "OFF" to "ON", it indicates that the movable shelf to be moved has moved from the retracted position to the transfer position.

[0071] The interlock communication between the first communication device 20 and the second communication device 40 includes transmitting transport information from the first communication device 20 to the second communication device 40 and transmitting storage information from the second communication device 40 to the first communication device 20. The first communication device 20 and the second communication device 40 are, for example, optical communication devices that perform optical communication, and serial communication is used as the method for sending and receiving information in interlock communication.

[0072] The storage control device 70 may include a processor such as a CPU or MPU and non-volatile or volatile semiconductor memory (e.g., RAM, ROM, flash memory, EPROM, EEPROM). For example, the storage control device 70 may be a microcontroller such as an MCU.

[0073] The storage control device 70 is connected to each of the multiple second communication devices 40 by wire or wireless. In addition, the storage control device 70 constantly transmits storage information from the second communication device 40 to the first communication device 20 in interlock communication. In interlock communication, the storage control device 70 constantly acquires transport information from the first communication device 20 via one of the second communication devices 40.

[0074] The storage control device 70 can move each shelf 50 to the transfer position. The transport vehicle 10 transmits transport information to the second communication device 40 via the first communication device 20 in interlock communication. The storage control device 70 obtains transport information from the second communication device 40 corresponding to the stopping position where the transport vehicle 10 has stopped in interlock communication. The storage control device 70 moves the shelf 50 (target for advancement) specified by the CS_0 signal and CS_1 signal in the transport information from the retracted position to the transfer position.

[0075] The storage control device 70 has information on which of the multiple shelves 50 has advanced to the transfer position. The storage control device 70 also has information on which stopping position the transport vehicle 10 is at. For example, the storage control device 70 constantly knows which stopping position the transport vehicle 10 is at by knowing which second communication device 40 the transport vehicle 10 is acquiring information from. Here, "knowing" includes acquiring some kind of information.

[0076] The following describes an example of the unloading operation according to this embodiment. As an example of the unloading operation, the operation when the transport vehicle 10 unloads an item 100 placed on shelf 50-2 in the second storage unit 310 will be explained using Figure 6. Figure 6 shows the changes in the signal state of transport information and storage information during the unloading operation.

[0077] The vehicle control device 7 acquires information about the loading area 60 at the unloading destination from the higher-level controller. In other words, the loading area 60 at the unloading destination is set in the vehicle control device 7. Here, the information about the loading area 60 at the unloading destination includes, for example, information about the shelf 50-2 at the unloading destination (hereinafter referred to as "unloading destination shelf information") and the position where the transport vehicle 10 should stop in order to unload the goods 100 (hereinafter referred to as "unloading stop setting position"). The unloading destination shelf information is information indicating the movable shelf to which the goods will be unloaded.

[0078] The vehicle control device 7 stops the transport vehicle 10 at the unloading stop setting position, which is one of several stopping positions that corresponds to the loading section 60 at the unloading destination. When the transport vehicle 10 stops at the unloading stop setting position, interlock communication takes place between the first communication device 20 and the second communication device 40. In the following explanation, the case where the second communication device 40 corresponding to the unloading stop setting position is "second communication device 40c" will be explained as an example. During interlock communication, transport information is constantly transmitted from the first communication device 20 to the second communication device 40c, and storage information is constantly transmitted from the second communication device 40c to the first communication device 20.

[0079] The movable shelf to be moved is shelf 50-2. When the transport vehicle 10 stops at the unloading stop setting position, the vehicle control device 7 controls the voltage level of the CS_0 signal to "ON" and the voltage level of the CS_1 signal to "OFF", thereby designating shelf 50-2 as the shelf to be moved (step S101). In other words, as illustrated in Figure 5, in step S101, the vehicle control device 7 controls the voltage level of the CS_0 signal to "ON" and the voltage level of the CS_1 signal to "OFF", thereby transmitting information about shelf 50-2 as the movable shelf to be moved to the storage control device 70.

[0080] The vehicle control device 7 specifies the item to be brought out using the CS_0 signal and the CS_1 signal, and then changes the VALID signal from "OFF" to "ON" (step S102). When the storage control device 70 detects that the VALID signal is "ON", it acquires the voltage levels of the CS_0 signal and the CS_1 signal. The storage control device 70 determines the movable shelf to be brought out from the combination of the acquired voltage levels of the CS_0 signal and the CS_1 signal. This configuration makes it clear at what timing the voltage levels of the CS_0 signal and CS_1 signal are used to specify the movable shelf, thus preventing the incorrect movable shelf from being selected.

[0081] As illustrated in Figure 5, the storage control device 70 has access target identification information that shows the relationship between the combination of voltage levels of the CS_0 signal and the CS_1 signal and the access target specified by each combination. The storage control device 70 determines that the access target is shelf 50-2 by obtaining the access target corresponding to the combination of voltage levels of the CS_0 signal and the CS_1 signal from the access target identification information.

[0082] When the storage control device 70 identifies the item to be unloaded, it controls the L_REQ signal from "OFF" to "ON" as a request signal for unloading (step S103).

[0083] When the vehicle control device 7 detects that the L_REQ signal controlled in step S103 is "ON", it controls the TR_REQ signal from "OFF" to "ON" (step S104). When the storage control device 70 detects that the TR_REQ signal is "ON", it starts moving the shelf 50-2, which is the target of the advance, from the retracted position to the transfer position (step S105). In addition, when the storage control device 70 detects that the target of the advance has been identified by detecting that the VALID signal is "ON", it may start moving the shelf 50-2, which is the target of the advance, from the retracted position to the transfer position regardless of whether the TR_REQ signal is "ON" or not.

[0084] When the storage control device 70 has finished moving the shelf 50-2 to the transfer position, it controls the READY signal from "OFF" to "ON" (step S106). When the vehicle control device 7 detects the "ON" READY signal, it controls the BUSY signal from "OFF" to "ON" to start the unloading operation of the goods 100 on the transport vehicle 10 (step S107).

[0085] For example, when the transport vehicle 10 starts unloading, it lowers the holding unit 14 and places the item 100 on the unloading destination, the placement unit 60, on the shelf 50-2. When the storage control device 70 detects that an item has been placed on the unloading destination, the detection unit 45 detects that an item has been placed on the unloading destination, it controls the L_REQ signal from "ON" to "OFF" (step S108).

[0086] When the transport vehicle 10 places the goods 100 on the loading area 60 at the unloading destination, it raises the holding unit 14 to a predetermined position and retracts the holding unit 14 from the lifting area S. This completes the unloading operation. When the L_REQ signal is "OFF" and the unloading operation is complete, the vehicle control device 7 controls the BUSY signal from "ON" to "OFF" (step S109) and controls the TR_REQ signal from "ON" to "OFF" (step S110). Furthermore, when the vehicle control device 7 controls the BUSY signal from "ON" to "OFF", it controls the COMPT signal from "OFF" to "ON" (step S111).

[0087] When the vehicle control device 7 detects the COMPT signal to be "ON", it moves the shelf 50-2, which is in the transfer position, to the retracted position (step S112). Once the movement of the shelf 50-2 to the retracted position is complete, the vehicle control device 7 controls the READY signal from "ON" to "OFF" (step S113).

[0088] When the storage control device 70 detects that the READY signal has changed from "ON" to "OFF", it controls the VALID signal from "ON" to "OFF" (step S114) and the COMPT signal from "ON" to "OFF" (step S115). Furthermore, when the storage control device 70 detects that the READY signal has changed from "ON" to "OFF", it controls both the CS_0 signal and the CS_1 signal to "OFF" in order to release the designation of the item to be brought out (step S116).

[0089] An example of the load-grabbing operation according to this embodiment will be described below. As an example of the load-grabbing operation, the operation when the transport vehicle 10 grabs an item 100 placed on shelf 50-2 in the second storage unit 310 will be explained using Figure 7. Figure 7 shows the changes in the signal states of transport information and storage information during the load-grabbing operation.

[0090] The vehicle control device 7 acquires information about the loading area 60 at the unloading destination from the higher-level controller. In other words, the loading area 60 at the unloading destination is set in the vehicle control device 7. Here, the information about the loading area 60 at the loading destination includes, for example, information about the shelf 50-2 at the loading destination (hereinafter referred to as "load-grabbing destination shelf information") and the position where the transport vehicle 10 should stop in order to grab the goods 100 (hereinafter referred to as "load-grabbing stop setting position"). The load-grabbing destination shelf information is information indicating the movable shelf to which the goods will be moved.

[0091] The vehicle control device 7 stops the transport vehicle 10 at a load-grabbing stop setting position, which is one of several stopping positions that corresponds to the loading section 60 at the load-grabbing destination. When the transport vehicle 10 stops at the load-grabbing stop setting position, interlock communication takes place between the first communication device 20 and the second communication device 40. In the following explanation, the case where the second communication device 40 corresponding to the load-grabbing stop setting position is "second communication device 40c" will be explained as an example. During interlock communication, transport information is constantly transmitted from the first communication device 20 to the second communication device 40c, and storage information is constantly transmitted from the second communication device 40c to the first communication device 20.

[0092] The movable shelf to be moved is shelf 50-2. When the transport vehicle 10 stops at the load-grabbing stop setting position, the vehicle control device 7 controls the voltage level of the CS_0 signal to "ON" and the voltage level of the CS_1 signal to "OFF", thereby designating shelf 50-2 as the target for movement (step S201). In other words, as illustrated in Figure 5, in step S201, the vehicle control device 7 controls the voltage level of the CS_0 signal to "ON" and the voltage level of the CS_1 signal to "OFF", thereby transmitting information about shelf 50-2 as the movable shelf to be moved to the storage control device 70.

[0093] The vehicle control device 7 specifies the item to be brought out using the CS_0 signal and the CS_1 signal, and then changes the VALID signal from "OFF" to "ON" (step S202). When the storage control device 70 detects that the VALID signal is "ON", it acquires the voltage levels of the CS_0 signal and the CS_1 signal. The storage control device 70 determines the movable shelf to be brought out from the combination of the acquired voltage levels of the CS_0 signal and the CS_1 signal.

[0094] As illustrated in Figure 5, the storage control device 70 has access target identification information that shows the relationship between the combination of voltage levels of the CS_0 signal and the CS_1 signal and the access target specified by each combination. The storage control device 70 determines that the access target is shelf 50-2 by obtaining the access target corresponding to the combination of voltage levels of the CS_0 signal and the CS_1 signal from the access target identification information.

[0095] When the storage control device 70 identifies the object to be moved, it controls the U_REQ signal from "OFF" to "ON" as a request signal for grasping the object (step S203).

[0096] When the vehicle control device 7 detects that the U_REQ signal controlled in step S203 is "ON", it controls the TR_REQ signal from "OFF" to "ON" (step S204). When the storage control device 70 detects that the TR_REQ signal is "ON", it starts moving the shelf 50-2, which is the target of advancement, from the retracted position to the transfer position (step S205). When the storage control device 70 detects that the target of advancement is "ON" by detecting the VALID signal, it may start moving the shelf 50-2, which is the target of advancement, from the retracted position to the transfer position regardless of whether the TR_REQ signal is "ON" or not.

[0097] When the storage control device 70 has finished moving the shelf 50-2 to the transfer position, it controls the READY signal from "OFF" to "ON" (step S206). When the vehicle control device 7 detects the "ON" READY signal, it controls the BUSY signal from "OFF" to "ON" to start the loading operation of the item 100 on the transport vehicle 10 (step S207).

[0098] For example, when the transport vehicle 10 starts the load-grabbing operation, it lowers the holding part 14 and holds the item 100 that is placed on the loading area 60 on the shelf 50-2 with the holding part 14. Then, with the item 100 held by the holding part 14, the transport vehicle 10 raises the holding part 14.

[0099] If the storage control device 70 detects that the item 100 is not placed on the loading area 60 at the loading destination by the detection unit 45, it determines that loading has been performed and controls the U_REQ signal from "ON" to "OFF" (step S208).

[0100] When the transport vehicle 10 places the item 100 on the loading area 60 at the load-grabbing destination, it raises the holding unit 14 to a predetermined position and retracts the holding unit 14 from the lifting area S. This completes the load-grabbing operation. When the U_REQ signal is "OFF" and the load-grabbing operation is complete, the vehicle control device 7 controls the BUSY signal from "ON" to "OFF" (step S209) and controls the TR_REQ signal from "ON" to "OFF" (step S210). Furthermore, when the vehicle control device 7 controls the BUSY signal from "ON" to "OFF", it controls the COMPT signal from "OFF" to "ON" (step S211).

[0101] When the vehicle control device 7 detects the COMPT signal to be "ON", it moves the shelf 50-2, which is in the transfer position, to the retracted position (step S212). Once the movement of the shelf 50-2 to the retracted position is complete, the vehicle control device 7 controls the READY signal from "ON" to "OFF" (step S213).

[0102] When the storage control device 70 detects that the READY signal has changed from "ON" to "OFF", it controls the VALID signal from "ON" to "OFF" (step S214) and the COMPT signal from "ON" to "OFF" (step S215). Furthermore, when the storage control device 70 detects that the READY signal has changed from "ON" to "OFF", it controls both the CS_0 signal and the CS_1 signal to "OFF" in order to release the designation of the item to be brought out (step S216).

[0103] An example of teaching operation according to this embodiment will be described below. Teaching operation is the process of having the transport vehicle 10 store the position of the holding part 14 when the transport vehicle 10 unloads the item 100, and the position of the holding part 14 when the item 100 is gripped by the holding part 14. In performing this teaching operation, the transport system HS is equipped with a teaching unit described in Japanese Patent Application No. 2017-76976 and Japanese Patent Application No. 2018-21812. Figure 8 shows the changes in the signal state of transport information and storage information during teaching operation. Figure 8 shows an example of teaching operation for shelf 50-2.

[0104] The conveying system HS holds the teaching unit with the holding unit 14 and performs the teaching operation. The conveying system HS uses the sequence for the load-grabbing operation shown in Figure 6 as the basis for the teaching operation sequence. Therefore, in Figure 8, steps that perform the same processing as the processing sequence shown in Figure 6 are indicated using the same step numbers. In the following explanation, a detailed explanation of the processing with the same step numbers as in Figure 6 will be omitted.

[0105] In step S103 shown in Figure 8, the storage control device 70 controls the L_REQ signal from "OFF" to "ON" if the item 100 is not present on the movable shelf to be taught (shelf 50-2 in the example shown in Figure 8). The storage control device 70 or the vehicle control device 7 outputs an error if the item 100 is present on the movable shelf to be taught. If an error is output, the teaching operation is forcibly terminated even if the teaching is not yet complete.

[0106] In this case, during the teaching operation, the transport vehicle 10 holds the teaching unit instead of the item 100, and does not unload the item 100. Therefore, the detection unit 45 does not detect the item, and if the storage control device 70 executes the process in step S108 as is, it cannot turn the L_REQ signal "OFF" and cannot proceed to step S109. In other words, the process in step S108 is a process that controls the L_REQ signal from "ON" to "OFF" triggered by the detection unit 45 detecting the item 100. Therefore, if the detection unit 45 does not detect the item 100, it may not be possible to proceed from step S108 to step S109.

[0107] Therefore, during the teaching operation, when the storage control device 70 detects that the BUSY signal has switched from "OFF" to "ON" (step S107), it controls the L_REQ signal from "ON" to "OFF" regardless of whether the detection unit 45 has detected the item 100 (step S308).

[0108] For example, in step S308, if the storage control device 70 detects that the BUSY signal has switched from "OFF" to "ON" due to the processing in step S107 shown in Figure 8, it will switch the L_REQ signal from "ON" to "OFF" after a certain period of time TP has elapsed since detecting the switch. This allows the transport system HS to execute the processing from step S109 onwards, as shown in Figure 8.

[0109] As described above, in the transport system HS according to this embodiment, when transferring articles 100 from the transport vehicle 10 to the storage device 30, the transport vehicle 10 designates the movable shelf to be advanced from the retracted position to the transfer position based on a combination of the voltage levels of the first signal and the voltage levels of the second signal. This allows the transport vehicle 10 to designate one of three or more movable shelves to be advanced to the transfer position using a single communication device (first communication device).

[0110] In the example shown in Figure 4, each movable shelf is arranged in pairs facing each other across the lifting area S, but this is not the only way. Each movable shelf may be suspended from the ceiling vertically on both or both sides of the ceiling track R. For example, as illustrated in Figure 9, each movable shelf may be suspended vertically on only one side of the ceiling track R. Also, as illustrated in Figure 10, the number of movable shelves arranged on one side of the ceiling track R may differ from the number of movable shelves arranged on the other side of the ceiling track R.

[0111] The above embodiment discloses the following configuration. (Composition 1) The transport system HS comprises a transport vehicle 10 for transporting articles 100, and a storage device 30 into which the articles 100 are transferred by the transport vehicle 10. The transport vehicle 10 is equipped with a first communication device 20 that communicates with the storage device 30 in order to transfer the articles 100. The storage device 30 is equipped with a second communication device 40 that communicates with the first communication device 20, and three or more movable shelves (shelves 50) for storing the articles 100. Each movable shelf is movable between a transfer position into which the articles 100 are transferred by the transport vehicle 10, and a retracted position into which it is moved away from the transfer position. The first communication device 20 transmits a transport signal to the second communication device 40, which includes a first signal and a second signal different from the first signal. The transport vehicle 10 specifies which movable shelf should be moved from the retracted position to the transfer position based on a combination of the voltage levels of the first signal and the voltage levels of the second signal. The voltage levels of the first signal and the second signal each include a high level, which is above a predetermined value, and a low level, which is below a predetermined value. (Configuration 2) In configuration 1, each movable shelf may be suspended from the ceiling in an orderly fashion on both or both sides of the track (e.g., ceiling track R) on which the transport vehicle 10 travels. (Composition 3) In configuration 1, the storage device 30 has four movable shelves, and the first and second movable shelves of the four movable shelves may be suspended from the ceiling in an orderly fashion, one above the other, on one side of the track on which the transport vehicle 10 travels. The third and fourth movable shelves of the four movable shelves may be suspended from the ceiling in an orderly fashion, one above the other, on the other side of the track. (Composition 4) In any of configurations 1 to 3, the storage device 30 may include a first fixed shelf suspended above the first and second movable shelves, and a second fixed shelf suspended above the third and fourth movable shelves. The transport vehicle 10 may include a holding section 14 for holding articles 100, and a lateral transfer mechanism 11 for moving the holding section 14 laterally to above the first or second fixed shelf. (Composition 5) In any of configurations 1 to 4, communication between the first communication device 20 and the second communication device 40 may be interlock communication in accordance with the SEMI E84 standard. (Composition 6) In any of configurations 1 to 5, the transport signal may further include a third signal different from the first and second signals. The transport vehicle 10 may specify the movable shelf to be moved from the retracted position to the transfer position based on a combination of the voltage levels of the first signal and the second signal when the voltage level of the third signal is transitioned from a low level to a high level or from a high level to a low level.

[0112] One or more of the requirements described in the embodiments described above may be omitted. Furthermore, the requirements described in the embodiments described above can be combined as appropriate. Also, the execution order of each procedure shown in this embodiment can be implemented in any order, as long as the result of the previous procedure is not used in a later procedure. Furthermore, even if the operations in the embodiments described above are described using terms such as "first," "next," and "followed by," it is not necessary to perform them in this order. [Explanation of Symbols]

[0113] HS... Conveyor system, 10... Transport vehicle, 20... First communication device, 30... Storage device, 40... Second communication device, 50... Shelving

Claims

1. A transport vehicle for carrying goods, A storage device comprising the transfer of the articles by the transport vehicle, The transport vehicle is equipped with a first communication device that communicates with the storage device in order to transfer the articles. The aforementioned storage device is A second communication device that communicates with the first communication device, The system comprises three or more movable shelves for storing the aforementioned articles, Each of the aforementioned movable shelves is movable between a transfer position where the articles are transferred by the transport vehicle and a retracted position where it is moved away from the transfer position. The first communication device transmits a carrier signal including a first signal and a second signal different from the first signal to the second communication device. The transport vehicle designates the movable shelf to be moved from the retracted position to the transfer position based on a combination of the voltage levels of the first signal and the voltage levels of the second signal. A transport system in which the voltage levels of the first signal and the second signal each include a high level which is greater than or equal to a predetermined value and a low level which is less than the predetermined value.

2. Each of the aforementioned movable shelves is suspended from the ceiling, arranged vertically on both or either one of the sides of the track on which the transport vehicle travels. The transport system according to claim 1.

3. The storage device has four of the movable shelves, Of the four movable shelves, the first and second movable shelves are suspended from the ceiling, arranged vertically on one side of the track on which the transport vehicle travels. The third and fourth movable shelves of the four movable shelves are suspended from the ceiling, arranged vertically on the other side of the track. The transport system according to claim 1.

4. The aforementioned storage device is A first fixed shelf suspended above the first movable shelf and the second movable shelf, A second fixed shelf suspended above the third movable shelf and the fourth movable shelf, The aforementioned transport vehicle is A holding part for holding the aforementioned article, The transport system according to claim 3, further comprising a lateral transfer mechanism for moving the holding portion laterally to above the first fixed shelf or the second fixed shelf.

5. The communication between the first communication device and the second communication device is an interlock communication in accordance with the SEMI E84 standard. The transport system according to claim 1.

6. The carrier signal further includes a third signal different from the first signal and the second signal, The transport system according to claim 1, wherein the transport vehicle designates the movable shelf to be moved from the retracted position to the transfer position based on a combination of the voltage level of the first signal and the voltage level of the second signal when the voltage level of the third signal is transitioned from a low level to a high level or from a high level to a low level.

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