Conveying system

Abstract

To provide a conveyance system capable of solving the problem that an automatic conveyance device cannot accurately position a cassette at a delivery port because a traveling guide line is interrupted by the delivery port and a reading sensor for reading the traveling guide line does not function.SOLUTION: The automatic conveying device includes a battery 32, electrodes 32a for charging the battery 32, a left tire driving unit 28 and a right tire driving unit disposed so as to sandwich the travel guide line 12, and reading sensors 60a and 60b for reading the travel guide line 12, charging terminals for charging the battery 32 in contact with the electrodes 32a are disposed at predetermined positions of the travel panel, and a position where the electrodes 32 and the charging terminals are in contact with each other is set as a base point in the travel direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a conveying system in which a traveling panel along which an automatic conveying device travels is arranged on the top plate of a processing device including a plurality of processing devices, and a traveling guide line for guiding the travel of the automatic conveying device is formed on the traveling panel. [Background technology]

[0002] A wafer has multiple devices such as ICs and LSIs formed on its surface, separated by planned dividing lines. The back side of the wafer is ground using a grinding machine to form it to the desired thickness, and then the wafer is divided into individual device chips using a cutting machine and laser processing machine. These chips are then used in electrical devices such as mobile phones and personal computers.

[0003] The present applicant has also developed and proposed a transport system in which a travel path is arranged using the top plate of a processing device including processing devices such as grinding devices, cutting devices, and laser processing devices, and a wafer storage device that stores multiple wafers, and an automatic transport vehicle (hereinafter referred to as an "AGV") travels between the processing devices to transport wafers from the wafer storage device to each processing device and to transport consumables (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-013892 Summary of the Invention [Problem to be solved by the invention]

[0005] The travel path is formed with a travel guide line that guides the travel of the AGV, and the AGV is equipped with drive wheels on the left and right sides of the travel guide line, as well as directional casters on the front and back and a reading sensor that reads the travel guide line.In addition, at the center of the bottom of the AGV, there is provided a lifting means that raises and lowers cassettes containing articles such as wafers to the article loading / unloading tables inside each processing device, and the travel path is formed with a delivery port that raises and lowers the cassettes and delivers the articles to the processing device.

[0006] However, when the AGV arrives at the delivery port where it will hand over the item, the delivery port is wide open, so the travel guide line is blocked by the delivery port, causing the reading sensor that reads the travel guide line to stop functioning, which results in the problem that the cassette cannot be accurately positioned at the delivery port.

[0007] Furthermore, although the reading sensor that reads the driving guidance line has the function of detecting the left-right positional deviation of the driving guidance line, there is a problem in that it is difficult to accurately detect the position of the driving guidance line in the forward-backward direction, which is the direction of travel of the driving guidance line.

[0008] The present invention has been made in consideration of the above facts, and its main technical objective is to provide a conveying system that can solve the problem that the AGV's travel guide line is interrupted by the delivery port, causing the reading sensor that reads the travel guide line to stop functioning, making it impossible to accurately position the cassette at the delivery port. [Means for solving the problem]

[0009] In order to solve the above-mentioned main technical problem, according to the present invention, a conveying system is provided in which a traveling panel on which an automatic conveying device travels is arranged on the top plate of a processing device including a plurality of processing devices, and a traveling guide line is formed on the traveling panel to guide the travel of the automatic conveying device, wherein the automatic conveying device includes a battery, an electrode for charging the battery, a left tire drive unit and a right tire drive unit arranged on either side of the traveling guide line, and a reading sensor for reading the traveling guide line, and a charging terminal for contacting the electrode to charge the battery is arranged at a required position on the traveling panel, and the position where the electrode and the charging terminal come into contact is used as the base point of the traveling direction.

[0010] The automatic conveying device includes front wheels arranged in front of the left tire drive unit and the right tire drive unit, rear wheels arranged behind the left tire drive unit and the right tire drive unit, an opening formed in a central area surrounded by the left tire drive unit, the right tire drive unit, the front wheels, and the rear wheels, and a belt winding means that winds a belt attached to one end of a cassette that stores articles through the opening and raises and lowers the cassette, and the traveling panel is formed with a transfer port through which the cassette is lowered to hand over the articles to the processing device, and it is preferable that the charging terminal be arranged in an area where the electrodes come into contact when the transfer port and the cassette physically coincide as the automatic conveying device travels.

[0011] Furthermore, it is preferable that contact between the charging terminal and the electrode is detected by a change in torque of the right tire driving unit or the left tire driving unit, and the right tire driving unit and the left tire driving unit are stopped starting from the detected position. [Effects of the Invention]

[0012] The conveying system of the present invention is a conveying system in which a traveling panel along which the automatic conveying device travels is arranged on the top plate of a processing device which includes a plurality of processing devices, and a traveling guide line is formed on the traveling panel to guide the travel of the automatic conveying device.The automatic conveying device is composed of a battery, an electrode for charging the battery, a left tire drive unit and a right tire drive unit arranged on either side of the traveling guide line, and a reading sensor for reading the traveling guide line.A charging terminal that contacts the electrode to charge the battery is arranged at a required position on the traveling panel, and the position where the electrode and the charging terminal contact is used as the starting point of the traveling direction.This solves the problem that when the automatic conveying device arrives at the destination processing device, the traveling guide line is interrupted by the transfer port, causing the reading sensor that reads the traveling guide line to stop functioning and making it impossible to accurately position the cassette at the transfer port. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a transport system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of an automatic conveyance device of the conveyance system shown in FIG. [Figure 3] 3 is a perspective view showing a state in which a cover is removed from the main body of the automatic conveying device shown in FIG. 2. FIG. [Figure 4] 3 is a perspective view of the automatic transport device shown in FIG. 2 as seen obliquely from the front. [Figure 5] (a) is a perspective view showing the state in which the automatic transport device approaches the transfer port on the target processing device, and (b) is a perspective view showing the state in which the electrode of the automatic transport device shown in (a) has come into contact with the charging terminal and stopped. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a transport system configured based on the present invention will be described in detail with reference to the accompanying drawings.

[0015] A conveyance system 2 of this embodiment is shown in Fig. 1. In the illustrated conveyance system 2, a traveling panel 10 on which a plurality of automatic conveyance devices (hereinafter referred to as "AGVs") (A) to (E) travel is disposed on a top plate 6 of a processing device 4 including a plurality of processing devices, and a traveling guide line 12 for guiding the traveling of the AGVs (A) to (E) is formed on the traveling panel 10.

[0016] The transport system 2 is equipped with a server 100 that controls and manages the travel of each AGV by communicating with each AGV. The server 100 is configured with a control program for controlling and managing the travel of each AGV, and control signals including information about the position of each AGV, information about the route each AGV should travel, and information about the speed when traveling through each area on the route are transmitted from an antenna 110 connected to the server 100 to the AGVs (A) to (E) traveling on the travel panel 10. The server 100 is equipped with a display means (monitor) 102 that an operator refers to when managing the transport system 2, including the travel of each AGV. The display means 102 is a touch panel type, and the operator can give instructions to the server 100 by operating a keyboard, buttons, etc. displayed on the screen.

[0017] The processing equipment 4 in this embodiment includes, for example, an article storage device 4a that manages articles, and a first processing device 4b, a second processing device 4c, and a third processing device 4d into which articles are transferred by AGVs (A) to (E). Examples of articles stored in and transferred from the article storage device 4a include workpieces such as semiconductor wafers that are processed by the first to third processing devices 4b to 4d, and processing tools used in processing by the first to third processing devices 4b to 4d. Examples of such processing tools include cutting blades used in cutting workpieces and grinding wheels with grinding stones used in grinding workpieces to thin them. Furthermore, workpieces processed by the first to third processing devices 4b to 4d and used processing tools are also transferred from the first to third processing devices 4b to 4d and transferred into the article storage device 4a by AGVs (A) to (E). In the illustrated conveyance system 2, one article storage device 4a and first to third processing devices 4b to 4d are provided as processing devices 4, but the number of article storage devices and processing devices constituting the processing device 4 can be arbitrarily set. In addition, the size and shape of the traveling panel 10 formed on the top plate 6 and the number of AGVs traveling on the traveling panel 10 can be arbitrarily set as needed.

[0018] A traveling panel 10 is disposed on the top plate 6 of the processing device 4, and the plurality of processing devices 4 are connected to one another by the traveling panel 10. The traveling panel 10 is formed with transfer openings 10a to 10d through which articles are delivered between the AGVs (A) to (E) and the processing devices 4. Although not shown, each top plate 6 of the processing devices 4 also has a transfer opening corresponding in position and size to the transfer openings 10a to 10d. Then, articles such as workpieces and processing tools are delivered between the AGVs (A) to (E) and the processing devices 4 through the transfer openings 10a to 10d of the traveling panel 10 and the transfer openings formed in each top plate 6.

[0019] As described above, the upper surface of the traveling panel 10 is provided with a travel guide line 12 for guiding the travel of the AGVs (A)-(E). The positions on the traveling panel 10 are defined by XY coordinates (not shown). The AGVs (A)-(E) travel along paths set based on the XY coordinates, as shown in FIG. 2, on the traveling guide line 12. The AGVs transport workpieces and processing tools received from the article storage device 4a to the first to third processing devices 4b-4d, and transport workpieces processed by the first to third processing devices 4b-4d and processing tools removed for replacement to the storage device 4a. As shown in FIG. 1, the traveling panel 10 is provided with a fall prevention wall 14 to prevent the AGVs (A)-(E) from falling off the traveling panel 10 even if they deviate from the travel guide line 12.

[0020] The AGV (A) of this embodiment will be described with reference to Figures 2 and 3. Note that since the AGVs (B) to (E) have the same configuration as the AGV (A), the description of the AGVs (B) to (E) will be omitted.

[0021] As shown in FIG. 2, the AGV (A) includes a main body 16 on which electrical components (described later) are mounted, and a cover 18 that covers the main body 16.

[0022] The AGV (A) shown in FIG. 2 will be described with reference to FIG. 3, which shows the AGV (A) disassembled into the main body 16 and the cover 18 and viewed obliquely from the rear. Note that FIG. 3 shows a state in which a cassette 42 is lowered when the AGV (A) stores and transports workpieces and processing tools. The main body 16 includes a frame 20 formed of a single metal plate on which various electrical components (described later) are mounted. An opening 20a is formed in the center of the frame 20, and the frame 20 includes a front support wall 22 extending upward from the front end of the opening 20a and a rear support wall 24 extending upward from the rear end of the opening 20a. Note that the front-rear and left-right directions of the AGV (A) are indicated by arrows in FIGS. 2 and 3.

[0023] As shown in FIG. 3, the AGV (A) includes a battery 32 that supplies power to each electrical component, electrodes 32a, 32a (see FIG. 4) disposed on the front of the battery 32 for charging the battery 32, a left tire drive unit 28, a right tire drive unit 30, and a front reading sensor 60a and a rear reading sensor 60b that read the travel guide line 12 formed on the travel panel 10. As can be seen from FIGS. 2 and 3, the left tire drive unit 28 and the right tire drive unit 30 are disposed so as to sandwich the travel guide line 12. The sensors that read the travel guide line 12 are not necessarily limited to the front reading sensor 60a and the rear reading sensor 60b as described above, and may instead include only the front reading sensor 60a, for example.

[0024] As shown in FIG. 3, the left tire drive unit 28 is supported by the left support piece 26 of the frame 20. The right tire drive unit 30 is supported by the right support piece (not visible in FIG. 3) of the frame 20. A pair of left and right front wheels 38 (the right side is not visible) are disposed in front of the left tire drive unit 28 and the right tire drive unit 30, and a pair of left and right rear wheels 40 are disposed behind the left tire drive unit 28 and the right tire drive unit 30. The front wheels 38 and the rear wheels 40 are both directional casters and are attached to the frame 20 so as to be rotatable about an axis extending in the vertical direction. The left tire drive unit 28 includes a left tire 28a and a left tire drive source 28b that rotates the left tire 28a, and the right tire drive unit 30 includes a right tire 30a and a right tire drive source 30b that rotates the right tire 30a. The left tire drive source 28b and the right tire drive source 30b are configured, for example, by electric motors (pulse motors), and by adjusting the rotational speed and rotational direction of the above-mentioned left tire 28a and right tire 30a using the left tire drive source 28b and the right tire drive source 30b, the AGV (A) can move forward, backward, turn right, turn left, and turn on the spot.

[0025] The opening 20a is formed in a central area surrounded by the left tire drive unit 28, the right tire drive unit 30, the front wheels 38, 38, and the rear wheels 40, 40, which are mounted on the frame 20. The AGV (A) is equipped with a belt winding means 17 that raises and lowers a cassette 42 containing articles through the opening 20a. The belt winding means 17 will be described in more detail below.

[0026] The belt winding means 17 includes a lift motor 34 and a driver 36 that controls the lift motor 34. The lift motor 34 lifts and lowers a cassette 42 containing articles to be transported via two left belts 44 and two right belts 46 attached to one end (top surface) of the cassette 42. The lift motor 34 in this embodiment is disposed behind the rear support wall 24 of the frame 20, and is fixed to the top surface of the frame 20 via an appropriate fixture (not shown).

[0027] The cassette 42, which is raised and lowered by the lifting motor 34, is formed in a box shape with a vertical dimension (thickness) that is smaller than the dimensions in the front-rear and left-right directions. The cassette 42 has a storage section 42a that stores articles, and a flip-up cover section 42b that opens and closes an opening (not shown) of the storage section 42a.

[0028] 3, the two left belts 44 are attached to the upper left surface of the storage section 42a of the cassette 42 at a distance from each other in the front-to-rear direction and extend upward. The upper portion of the left belt 44 passes through an opening 20a in the frame 20 and is guided by a left guide roller 48. This left guide roller 48 is rotatably supported by left guide roller support portions 22a, 24a formed on the front support wall 20a and rear support wall 24 of the frame 20.

[0029] The two right belts 46 are attached to the upper right surface of the storage section 42a of the cassette 42 at a distance from each other in the front-to-rear direction and extend upward. The upper portion of the right belt 46 passes through an opening 20a in the frame 20 and is guided by a right guide roller 50. The right guide roller 50 is rotatably supported by right guide roller support sections 22b, 24b formed on the front support wall 20a and the rear support wall 24 of the frame 20.

[0030] The upper ends of the left belt 44 and the right belt 46 are connected to take-up rollers 52, which are respectively disposed between a left guide roller 48 and a right guide roller 50. The take-up rollers 52 are rotatably supported by take-up roller support portions 22c, 24c formed on the front support wall 20 and the rear support wall 24 of the frame 20, and are connected to the lift motor 34.

[0031] The cassette 42 can be raised and lowered in the direction indicated by arrow R1 by operating the lifting motor 34 of the belt winding means 17 to rotate the winding roller 52 forward or backward to wind or unwind the left belt 44 and the right belt 46. When the AGV (A) travels on the traveling panel 10, the cassette 42 is housed inside the main body 16 through the opening 20a by winding up the left belt 44 and the right belt 46.

[0032] The driver 36 controls the drive current output to the left tire drive source 28b, the right tire drive source 30b, and the lift motor 34. In this embodiment, the driver 36 is disposed adjacent to the lift motor 34 and is fixed to the rear surface of the rear support wall 24 of the frame 20 via an appropriate fastener (not shown). The drive current output by the driver 36 is controlled by a control means 54 mounted on the rear of the frame 20. The control means 54 is configured by a computer having an appropriate processor and memory, and power is supplied to the control means 54 from the battery 32.

[0033] The control means 54 is provided with an antenna 56, and receives a control signal transmitted from the server 100 via the antenna 56, and transmits information about the AGV (A) managed by the control means 54 to the server 100. The cover 18 is formed with a hole 18a that exposes the antenna 56 to the outside when the cover 18 is attached to the main body 16.

[0034] The AGV (A) is operated based on a control signal sent by the server 100, and the AGV (A) travels along a route defined by the XY coordinates on the travel panel 10 instructed by the control signal from the server 100 while reading the travel guide line 12 with the front reading sensor 60a and rear reading sensor 60b, and the position of the AGV (A) is grasped to a certain degree of accuracy based on the number of rotations and the angle of rotation of the left tire 28a rotated by the left tire driving source 28b and the right tire 30a rotated by the right tire driving source 30b.

[0035] As can be seen from the perspective view of the AGV (A) seen from the left front in FIG. 4, the battery 32 is disposed in front of the main body 16 and is equipped with electrodes 32a, 32a for supplying power to the battery 32 to charge it (for convenience of explanation, FIG. 4 omits components of the main body 16 other than the battery 32, the front reading sensor 60a, and the rear reading sensor 60a). Furthermore, electrode holes 18b, 18b exposing the electrodes 32a, 32a are formed in the front of the cover 18 at positions corresponding to the electrodes 32a. The electrodes 32a, 32a do not necessarily have to be formed directly on the battery 32. For example, the electrodes 32a, 32a alone may be disposed in positions corresponding to the electrode holes 18b, 18b in the front of the cover 18, and the battery 32 may be disposed in a position within the AGV (A) away from the electrodes 32a, 32a.

[0036] 1 and 5(a), charging terminals 142, 142 for supplying external power to the battery 32 by contacting the electrodes 32a, 32a of the AGV(A) are provided at required positions on the traveling panel 10. In the illustrated embodiment, the charging terminals 142, 142 are formed in an area where the electrodes 32a, 32a come into contact at a position where the transfer openings 10a to 10d of each processing device 4 and the cassette 42 of the AGV(A) physically coincide as the AGV(A) travels, and are provided on the fall prevention wall 14 at the end of the traveling direction of the AGV(A), as shown in FIG.

[0037] The functions and actions of the electrodes 32a, 32a and charging terminals 142, 142 of the battery 32 in the transport system 2 of the above embodiment will be described below.

[0038] The AGV (A) in the conveying system 2 of this embodiment is operated based on a control signal transmitted by the server 100 described above, and when transporting items such as workpieces and processing tools from the item storage device 4a, the AGV (A) is positioned directly above the delivery opening 10a of the item storage device 4a, and the lifting motor 34 described above is operated to lower the cassette 42 from the delivery opening 10a into the item storage device 4a.

[0039] Once the workpieces or processing tools have been stored in the cassette 42 in the article storage device 4a, the lifting motor 34 of the belt winding means 17 is operated to lift the cassette 42 and store it in the main body 16 of the AGV (A). Next, the AGV (A) travels along a predetermined route set by the XY coordinates on the traveling panel 10 to transport the workpieces to another processing device 4, for example, the first processing device 4b. At this time, the AGV (A) continues traveling while reading the travel guide line 12 on the traveling panel 10 instructed by a control signal from the server 100 and the codes indicating the XY coordinates of each position formed at intervals on the travel guide line 12 using the front reading sensor 60a and rear reading sensor 60b.

[0040] At the delivery opening 10b where the AGV(A) delivers the article, the travel guide line 12 is interrupted, making it impossible to accurately grasp the XY coordinates indicating the position of the AGV(A), which can cause a problem in that the cassette 42 cannot be accurately positioned above the delivery opening 10b of the first processing device 4b, which is the destination. Therefore, in this embodiment, as shown in Figure 5(a), when the AGV(A) travels toward the delivery opening 10b of the first processing device 4b, charging terminals 142, 142 are arranged on the traveling panel 10 at the destination after passing the delivery opening 10b, and as shown in Figure 5(b), the electrodes 32a, 32a of the AGV(A) can be brought into contact with the charging terminals 142, 142 to stop the AGV(A).

[0041] The stop of the AGV(A) can be detected, for example, by a change in the drive torque of the left tire drive source 28b and the right tire drive source 30b that drive the left tire 28a and the right tire 30a. More specifically, when the electrodes 32a, 32a of the AGV(A) come into contact with the charging terminals 142, 142 and the AGV(A) stops, the drive torques of the left tire drive source 28b and the right tire drive source 30b are sent from the control means 54 of the AGV(A) to the server 100. The server 100 then detects a sudden increase in the drive torque, thereby detecting the stop of the AGV(A), and transmits a control signal from the server 100 to the AGV(A) to stop the power supply to the left tire drive source 28b and the right tire drive source 30b. Since the charging terminals 142, 142 are arranged in the required positions as described above, when the electrodes 32a, 32a of the AGV (A) come into contact with the charging terminals 142, 142 and stop, the transfer port 10b of the first processing device 4b and the cassette 42 of the AGV (A) are physically aligned.

[0042] As described above, when the electrodes 32a, 32a of the AGV(A) come into contact with the charging terminals 142, 142 and the AGV(A) stops above the transfer opening 10b of the first processing device 4b, the server 100 determines that the AGV(A) is accurately positioned at the XY coordinates of the transfer opening 4b and corrects the position information of the AGV(A) using that position as the base point for the traveling direction of the AGV(A). As a result, even if there is a deviation in the forward / backward position information in the traveling direction while the AGV(A) is traveling toward the first processing device 4b, when the electrodes 32a, 32a come into contact with the charging terminals 142, 142 arranged at the required positions and the AGV(A) stops, the position information on the traveling panel 10 of the AGV(A) is accurately corrected using that position as the base point, and the accurate position of the AGV(A) in the traveling direction thereafter is determined.

[0043] As described above, when the electrodes 32a, 32a of the AGV(A) are in contact with the charging terminals 142, 142 and are stopped, the transfer opening 10b of the first processing device 4b and the cassette 42 of the AGV(A) are physically aligned, so that the belt winding means 17 can be operated to lower the cassette 42 through the transfer opening 10b of the first processing device 4b into the first processing device 4b, allowing the workpieces or processing tools contained in the cassette 42 to be carried in. In other words, this solves the problem of the transfer opening 10b blocking the travel guide line 12, preventing the reading sensors 60a, 60b that read the travel guide line 12 from functioning, making it impossible to accurately position the cassette 42 at the transfer opening 10b.

[0044] Furthermore, the electrodes 32a, 32a of the AGV(A) come into contact with the charging terminals 142, 142 and stop, and while the cassette 42 is lowered to carry the workpiece or processing tool into the first processing device 4b, the battery 32 of the AGV(A) is charged. By arranging such charging terminals 142, 142 at required positions corresponding to all of the transfer openings 10a to 10d corresponding to the article storage device 4a and the first to third processing devices 4b to 4d that make up the processing device 4, the AGV(A) is charged regardless of whether it is at any of the transfer openings 10a to 10d, and the problem of the battery 32 running low and stopping mid-transfer is avoided.

[0045] The above-mentioned effects are obtained by all AGVs (A) to (E) traveling on the traveling panel 10. That is, each time an AGV reaches the transfer openings 10a to 10d corresponding to the article storage device 4a and the first to third processing devices 4b to 4d that constitute the processing device 4, the transfer openings 10a to 10d and the cassettes 42 are brought into a physically aligned state, and the position information in the traveling direction is corrected and charging is performed using that position as the base point. [Explanation of symbols]

[0046] 2:Transport system 4: Processing equipment 4a: Goods storage device 4b to 4d: First to third processing devices 6: Top plate 10: Travel panel 10a~10d: Delivery area 12: Driving guidance line 14: Fall prevention wall 142: Charging terminal 16: Main body 17: Belt winding means 18: Cover 20: Frame 20a:Aperture 22: Front support wall 24: Rear support wall 26:Left side support piece 28: Left tire drive unit 28a: Left tire 28b: Left tire drive source 30: Right tire drive unit 30a: Right tire 30b: Right tire drive source 32: Battery 32a: Electrode 34: Lifting motor 36: Driver 38: Front wheel 40: Rear wheel 42: Cassette 44: Left belt 46: Right belt 48: Left guide roller 50: Right guide roller 52: Winding roller 54: Control means 56: Antenna 60a: Front reading sensor 60b: Rear reading sensor 100: Server 102:Display means 110: Antenna

Claims

1. A conveyance system in which a travel panel on which an automatic conveyance device travels is arranged on a top plate of a processing device including a plurality of processing devices, and a travel guide line for guiding the travel of the automatic conveyance device is formed on the travel panel, the automatic transport device is configured to include a battery, an electrode for charging the battery, a left tire drive unit and a right tire drive unit disposed on either side of the travel guide line, and a reading sensor for reading the travel guide line; A charging terminal that contacts the electrode to charge the battery is disposed at a predetermined position on the traveling panel, and the position where the electrode and the charging terminal contact each other is set as the starting point of the traveling direction.

2. The automatic transport device includes front wheels disposed in front of the left tire drive unit and the right tire drive unit; rear wheels disposed behind the left tire driving unit and the right tire driving unit; an opening formed in a central region surrounded by the left tire driving portion, the right tire driving portion, the front wheels, and the rear wheels; a belt winding means for winding a belt attached to one end of a cassette containing articles through the opening to raise and lower the cassette; Including, The conveying system described in claim 1, wherein the traveling panel has a transfer port through which the cassette is lowered to transfer the article to the processing device, and the charging terminal is arranged in an area where the electrode comes into contact when the automatic conveying device travels and the transfer port and the cassette physically coincide.

3. The conveying system described in claim 2, wherein contact between the charging terminal and the electrode is detected by a change in torque of the right tire drive unit or the left tire drive unit, and the right tire drive unit and the left tire drive unit are stopped starting from the detected position.

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