Unmanned transport vehicle and unmanned transport system

Abstract

In an unmanned transport vehicle (1), a controller causes an arm drive system to move an arm (15-2) from the unmanned transport vehicle (1) onto a transport path of an article (101), and when the unmanned transport vehicle (1) is traveling in parallel with the article (101), the controller reduces the travel speed of the unmanned transport vehicle (1) below the transport speed of the article (101), bringing the arm (15-2) into contact with the article (101). The arm drive system then moves the arm (15-2) from the transport path of the article (101) back to the unmanned transport vehicle (1) thereby moving the article (101) together with the arm (15-2) and accommodating the article (101) in an accommodation part, specifically onto an upper surface (11b).

Description

Automated Guided Vehicle and Automated Guided System

[0001] The present invention relates to an automated guided vehicle and an automated guided system.

[0002] A certain automated guided vehicle includes two arms each having a claw portion that can be extended and retracted at its respective tip, and (a) travels parallel to the conveyance direction of an article at a speed higher than the conveyance speed of the article being conveyed by a conveyor, (b) extends the upstream arm of the travel route, and extends the downstream arm when the upstream arm has moved to the position of the article, (c) projects the claw portion when there is an article between the two arms, and (d) draws in the two arms while bringing the claw portion into contact with the article, thereby drawing the article into the automated guided vehicle (see, for example, Patent Document 1).

[0003] Patent No. 7448894 Specification

[0004] The above-described automated guided vehicle extends the two arms in sequence for drawing in an article, and then projects the claw portion and draws the article into the automated guided vehicle with the two arms. Therefore, the time required to draw the article into the automated guided vehicle becomes long.

[0005] The present invention has been made in view of the above problems, and an object thereof is to obtain an automated guided vehicle and an automated guided system in which the time required to accommodate an article in the automated guided vehicle is short.

[0006] The automated guided vehicle according to the present invention is an automated guided vehicle that travels along a predetermined travel path and picks up and transports articles being transported along a predetermined transport path, and comprises a travel drive system that drives the automated guided vehicle along the travel path, a storage section in which the articles are stored, an arm located downstream of the storage section in the travel path, an arm drive system that moves the arm from the automated guided vehicle onto the transport path and moves the arm from the transport path back to the automated guided vehicle, and a controller that controls the travel drive system and the arm drive system. The controller (a) moves the arm from the automated guided vehicle onto the transport path using the arm drive system, and (b) when the automated guided vehicle is traveling parallel to the articles, the travel speed of the automated guided vehicle is made lower than the transport speed of the articles so that the arm is in contact with the articles, and the arm drive system moves the arm from the transport path back to the automated guided vehicle, thereby moving the articles together with the arm and storing the articles in the storage section.

[0007] The automated guided vehicle system according to the present invention comprises the automated guided vehicle described above and a conveyor that transports the articles along the transport path.

[0008] According to the present invention, an automated guided vehicle and automated guided vehicle system can be obtained that require less time to load articles into the automated guided vehicle.

[0009] The above or other objects, features, and advantages of the present invention will become even more apparent from the following detailed description in conjunction with the accompanying drawings.

[0010] Figure 1 is a diagram illustrating the configuration of an automated guided vehicle (AGV) system according to an embodiment of the present invention. Figure 2 is a perspective view showing an example of the AGV 1 in Figure 1. Figure 3 is a diagram illustrating the operation of the arm of the AGV 1 shown in Figure 2. Figure 4 is a block diagram illustrating the electrical configuration of the AGV 1 shown in Figure 2. Figure 5 is a diagram illustrating the travel speed of the AGV 1 in Embodiment 1. Figure 6 is a diagram illustrating the operation of the AGV 1 in Embodiment 1 (1 / 2). Figure 7 is a diagram illustrating the operation of the AGV 1 in Embodiment 1 (2 / 2). Figure 8 is a flowchart illustrating the operation of the AGV 1 in Embodiment 2.

[0011] Embodiments of the present invention will be described below with reference to the figures.

[0012] Embodiment 1.

[0013] Figure 1 is a diagram showing the configuration of an automated guided vehicle (AGV) system according to an embodiment of the present invention. The AGV system shown in Figure 1 comprises an AGV 1, a conveyor 2, and a storage rack 3. The AGV 1 travels along a predetermined travel path, picks up and transports articles 101 being transported along the predetermined transport path, and delivers the articles 101 to the storage rack 3, which is the destination. The conveyor 2 is a roller conveyor or the like, laid along the transport path of the articles 101, and transports the articles 101 at a constant transport speed along the transport path. The travel path may be set virtually by the AGV 1 or a server (not shown) (i.e., by floor patterns unique to each position without placing members such as markers), or it may be set physically by members such as markers. The above-mentioned travel path and the above-mentioned transport path are partially parallel, and the articles 101 are picked up by the AGV 1 in the parallel portion.

[0014] Furthermore, item 101 is placed in packaging materials or cases such as cardboard boxes, and has a roughly rectangular parallelepiped shape in appearance.

[0015] Figure 2 is a perspective view showing an example of the automated guided vehicle (AGV) 1 in Figure 1. For example, as shown in Figure 2, the AGV 1 comprises a housing 11, the lower surface 11a of the housing 11 is equipped with a plurality of casters 12 (driven wheels) and a plurality of drive wheels 13 as a running system, and the upper surface 11b of the housing 11 is equipped with rails 14-1, 14-2 and arms 15-1, 15-2 as arm sections. Furthermore, the AGV 1 is equipped with an imaging device 16 on the upper surface 11b. The upper surface 11b is used as a storage section in which an article 101 is stored.

[0016] Each of the multiple drive wheels 13 is controlled independently, and the amount and direction of rotation of each wheel is used to move the unmanned transport vehicle 1 in a straight line or to turn.

[0017] Figure 3 is a diagram illustrating the operation of the arms of the automated guided vehicle 1 shown in Figure 2. For example, as shown in Figure 3, arms 15-1 and 15-2 are flat plate-shaped members arranged on rails 14-1 and 14-2. Rails 14-1 and 14-2 have a substantially flat shape and incorporate the arm drive system described later, which moves arms 15-1 and 15-2 in a straight line. In this embodiment, arms 15-1 and 15-2 move along a direction substantially perpendicular to the direction of travel. The arm drive system is, for example, a rack and pinion mechanism and motor, or a linear motor. Arm 15-1 is the upstream arm in the travel path of the automated guided vehicle 1 on the upper surface 11b which is the housing section, and arm 15-2 is the downstream arm in the travel path of the automated guided vehicle 1 on the upper surface 11b which is the housing section.

[0018] Furthermore, each arm 15-i (i=1,2) is equipped with a claw portion 21 at its tip and a claw portion 22 at its rear end. In this embodiment, the claw portions 21 and 22 are each connected to a pivot shaft and are rotated and extended by a motor (not shown). In the state shown in Figure 2, the claw portions 21 and 22 are housed inside the arm 15-i, and in the state shown in Figure 3, the claw portions 21 and 22 protrude from the inner surface of the arm 15-i (i.e., the side facing the housing).

[0019] Furthermore, the imaging device 16 is equipped with an image sensor such as a CCD (Charge Coupled Device) and captures an image of the area in front of the housing section (upper surface 11b) (i.e., a predetermined range on the conveyor 2) to generate an image.

[0020] Figure 4 is a block diagram showing the electrical configuration of the automated guided vehicle 1 shown in Figure 2. For example, as shown in Figure 4, the automated guided vehicle 1 includes a travel sensor 41, a travel drive system 42, the aforementioned arm drive system 43, a claw drive system 44 for extending and retracting the aforementioned claw parts 21 and 22, a communication device 45, and a controller 46.

[0021] The travel sensor 41 is a sensor that detects markers indicating the travel path. Existing markers indicating the travel path and the travel sensor 41 are used. The travel drive system 42 drives the drive wheels 13 with a motor or the like, and moves the unmanned transport vehicle 1 along the aforementioned travel path.

[0022] In Embodiment 1, the arm drive system 43 moves the arm 15-2 from the automated guided vehicle 1 onto the transport path (that is, extends the arm 15-2 onto the transport path of the conveyor 2), and moves the arm 15-2 from the transport path back to the automated guided vehicle 1 (that is, stores the arm 15-2 in the automated guided vehicle 1).

[0023] The communication device 45 communicates with an external server (not shown) via wireless communication or other means.

[0024] The controller 46 is a computer or ASIC (Application Specific Integrated Circuit) that executes a control program, and controls the travel drive system 42 and the arm drive system 43 based on the output of the travel sensor 41 and the imaging device 16 to move the unmanned transport vehicle 1 and to pick up items 101 from the conveyor 2.

[0025] In particular, the controller 46 (a) moves the arm 15-2 from the automated guided vehicle 1 to the transport path using the arm drive system 43, and (b) when the automated guided vehicle is traveling parallel to the article (after the automated guided vehicle 1 has overtaken the article 101), the controller 46 lowers the travel speed of the automated guided vehicle 1 to be lower than the transport speed of the article 101 (i.e., the transport speed of the conveyor 2) and, with the arm 15-2 in contact with the article 101, moves the arm 15-2 from the transport path to the automated guided vehicle 1 using the arm drive system 43, thereby moving the article 101 together with the arm 15-2 and storing the article 101 in the storage section (upper surface 11b).

[0026] In this embodiment, the controller 46 (a) uses the claw drive system 44 to make the claw portion 21 of the arm 15-2 protrude, and (b) with the arm 15-2 in contact with the article 101, moves the arm 15-2 from the transport path to the unmanned transport vehicle 1 using the arm drive system 43, thereby moving the article 101 together with the arm 15-2 while the article 101 is in contact with its claw portion 21, and storing the article 101 in the storage section (upper surface 11b).

[0027] Next, the operation of the automated guided vehicle 1 according to Embodiment 1 will be described. Figure 5 is a diagram illustrating the travel speed of the automated guided vehicle 1 in Embodiment 1. Figures 6 and 7 are diagrams illustrating the operation of the automated guided vehicle 1 in Embodiment 1.

[0028] The automated guided vehicle 1 is stationary and waiting at its home position (the position shown in Figure 1), and the controller 46 is monitoring the images captured by the imaging device 16. When an item 101 is transported on the conveyor belt 2, and the controller 46 detects the visible code 101a (in this case, a two-dimensional code) attached to the item 101, it decodes the visible code 101 to obtain the identification information of the item 101.

[0029] Furthermore, when the controller 46 detects the visible code 101a attached to the item 101, it controls the travel drive system 42 to start the movement of the automated guided vehicle 1. At this point, the item 101 is moving ahead of the automated guided vehicle 1. Then, as shown in Figure 5, for example, the controller 46 accelerates the automated guided vehicle 1 until its travel speed reaches a predetermined speed higher than the transport speed.

[0030] Then, the controller 46 determines, for example, based on the position of the visible code 101a in the captured image, that the arm 15-2 (position) has overtaken the item 101 in the travel direction and transport direction, and controls the arm drive system 43 to move the downstream arm 15-2 along the rail 14-2 onto the conveyor 2, as shown in Figure 6, and controls the claw drive system 44 to extend the claw portion 21 of the downstream arm 15-2. The controller 46 does not move the upstream arm 15-1 onto the conveyor 2.

[0031] Once the extension of the arm 15-2 is complete, the controller 46 uses the travel drive system 42 to reduce the travel speed of the automated guided vehicle 1 to a predetermined speed lower than the conveying speed of the conveyor 2. Then, if the controller 46 determines that the arm 15-2 is in contact with the item 101, based on, for example, the position of the visible code 101a in the captured image, it controls the arm drive system 43 to move the upstream arm 15-2 along the rail 14-2 towards the automated guided vehicle 1, as shown in Figure 7. At this time, since the item 101 is in contact with the arm 15-2 and the claw portion 21, it moves together with the arm 15-2 to the storage section (upper surface 11b) of the automated guided vehicle 1. For example, when the item 101 is in contact with the arm 15-2 and the item 101 is moving at the same speed as the automated guided vehicle 1, and the position of the visible code 101a in the captured image no longer changes substantially, it is determined that the arm 15-2 is in contact with the item 101.

[0032] After storing the item 101 in this manner, the automated guided vehicle 1 travels along its route to the destination (in this case, a predetermined location on the storage shelf 3). The destination is identified, for example, by a database or server based on the identification information of the item 101.

[0033] Then, when the automated guided vehicle 1 arrives at the destination, the controller 46 uses the claw drive system 44 to extend the claw portion 22 at the rear end of the arm 15-2 (or arms 15-1, 15-2), and then uses the arm drive system 43 to move the arm 15-2 (or arms 15-1, 15-2) forward (to a predetermined position on the storage shelf 3), pushing the item 101 into contact with the claw portion 22 and moving the item 101 to the predetermined position on the storage shelf 3.

[0034] Subsequently, the controller 46 retracts the claw portion 22 with the claw drive system 44 and returns the arm 15-2 (or arms 15-1, 15-2) to its original position, and then controls the travel drive system 42 to move the unmanned transport vehicle 1 along the travel path to the home position.

[0035] As described above, according to Embodiment 1, the controller 46 (a) moves the downstream arm 15-2 from the automated guided vehicle 1 to the transport path of the article 101 using the arm drive system 43, and (b) while the automated guided vehicle 1 is traveling parallel to the article 101, the travel speed of the automated guided vehicle 1 is lower than the transport speed of the article 101, and with the arm 15-2 in contact with the article 101, the arm drive system 43 moves the arm 15-2 from the transport path of the article 101 to the automated guided vehicle 1, thereby moving the article 101 together with the arm 15-2 and storing the article 101 in the storage section (upper surface 11b).

[0036] This allows the automated guided vehicle 1 to move at high speed until the downstream arm 15-2 overtakes the item 101, then decelerate to bring the downstream arm 15-2 into contact with the item 101 in a short time, and immediately pull the item 101 into the automated guided vehicle 1 using only the downstream arm 15-2. As a result, the time required to store the item 101 in the automated guided vehicle 1 is shortened.

[0037] Embodiment 2.

[0038] In Embodiment 2, depending on whether predetermined conditions are met, the article 101 is accommodated either by the downstream arm 15-2 only, or by both arms 15-1 and 15-2.

[0039] In Embodiment 2, the arm drive system 43 independently moves both arms 15-1 and 15-2 from the automated guided vehicle 1 onto the transport path, and also independently moves both arms 15-1 and 15-2 from the transport path back onto the automated guided vehicle 1.

[0040] In Embodiment 2, the controller 46 determines the weight of the article 101. For example, the controller 46 may encode the weight of the article 101 in the visible code described above and determine the weight of the article 101 by decoding the visible code; or it may refer to a database (not shown) based on the identification information of the article 101 obtained by decoding the visible code to determine the weight corresponding to that identification information; or it may determine the weight by receiving a notification from a server (not shown) indicating the weight of each article 101.

[0041] In Embodiment 2, the controller 46 determines, depending on the weight of the identified article 101, whether to accommodate the article 101 using only the downstream arm 15-2 (similar to Embodiment 1) or to accommodate the article 101 using both arms 15-1 and 15-2. If the weight of the identified article 101 is below a predetermined threshold, the controller 46 accommodates the article 101 using only the downstream arm 15-2; otherwise, it accommodates the article 101 using both arms 15-1 and 15-2.

[0042] Specifically, when the identified weight is less than or equal to a predetermined first threshold value (for example, 500 g), the controller 46 contacts the arm 15-2 with the article 101 in the same manner as in the first embodiment, and the arm drive system 43 moves the upstream arm 15-1 from the unmanned transport vehicle 101 onto the transport path. (b2) The claw drive system 44 projects the claws 21 of the arm 15-1 and the claws 21 of the arm 15-2. (b3) With the arm 15-2 in contact with the article 101, the arm drive system 43 moves the arms 15-1 and 15-2 from the transport path onto the unmanned transport vehicle 1, thereby moving the article 101 while abutting the article 101 against the claws 21 of the arm 15-1 and the claws 21 of the arm 15-2 and accommodating the article 101 in the accommodating portion (upper surface 11b). On the other hand, when the identified weight exceeds the above-described first threshold value, the controller 46 accommodates the article 101 in the accommodating portion (upper surface 11b) using only the downstream arm 15-2 in the same manner as in the first embodiment. By doing so, even when the article 101 is light, the article 101 is stably accommodated.

[0043] Also, in the second embodiment, the controller 46 adjusts the traveling speed of the unmanned transport vehicle 1 according to the weight of the identified article 101. Specifically, the controller 46 sets the traveling speed when the arm 15-2 is in contact with the article 101 to a predetermined first speed (a) when the identified weight is less than a predetermined first threshold value (for example, 500 g) or exceeds a predetermined second threshold value (second threshold value > first threshold value, for example, 1 kg), and sets the traveling speed when the arm 15-2 is in contact with the article 101 to a second speed lower than the first speed (b) when the identified weight is greater than or equal to the first threshold value and less than or equal to the second threshold value. By doing so, the contact pressure between the two increases, and the article 101 within a specific weight range is stably accommodated when the article 101 is accommodated using only the arm 15-2.

[0044] Next, the operation of the unmanned transport vehicle 1 in the second embodiment will be described. FIG. 8 is a flowchart for explaining the operation of the unmanned transport vehicle 1 in the second embodiment.

[0045] Similar to Embodiment 1, the automated guided vehicle 1 is stationary and waiting at the home position. When the controller 46 detects the visible code 101a attached to the article 101, it starts the running of the automated guided vehicle 1 (step S1), and at the same time decodes the visible code 101 to obtain the identification information of the article 101 and obtains the weight information (step S2).

[0046] Next, the controller 46 determines whether to accommodate the article 101 only with the downstream arm 15-2 of the two arms 15-1 and 15-2 based on the weight of the article 101 (step S3).

[0047] When it is determined to accommodate the article 101 only with the downstream arm 15-2, the controller 46 determines whether to set a lower running speed of the automated guided vehicle 1 when the arm 15-2 is in contact with the article 101 based on the weight of the article 101 (step S4).

[0048] When the controller 46 determines not to set a lower running speed of the automated guided vehicle 1 when the arm 15-2 is in contact with the article 101, it sets the running speed to the first speed V1 lower than the conveying speed. When the controller 46 determines to set a lower running speed of the automated guided vehicle 1 when the arm 15-2 is in contact with the article 101, it sets the running speed to the second speed V2 lower than the first speed V1.

[0049] Then, similar to Embodiment 1, when the controller 46 determines that the arm 15-2 (position) has overtaken the article 101 in the running direction and the conveying direction, it controls the arm driving system 43 to move the downstream arm 15-2 onto the conveyor 2 along the rail 14-2, and at the same time controls the claw driving system 44 to project the claw portion 21 of the downstream arm 15-2.

[0050] Once the extension of the arm 15-2 is complete, the controller 46 reduces the travel speed of the automated guided vehicle 1 to the speed V1 or V2 set as described above using the travel drive system 42. Then, when the downstream arm 15-2 makes contact with the item 101, the controller 46 picks up the item 101 using only the downstream arm 15-2 (step S6), and then transports the item 101 to the destination in the same manner as in Embodiment 1 (step S7).

[0051] On the other hand, if the controller 46 determines that the article 101 cannot be picked up using only the downstream arm 15-2, the controller 46 picks up the article 101 using both arms 15-1 and 15-2 as described above (step S8), and then, as in Embodiment 1, transports the article 101 to the destination (step S7).

[0052] The other configurations and operations of the automated guided vehicle system and automated guided vehicle according to Embodiment 2 are the same as those of Embodiment 1, so their description will be omitted.

[0053] Embodiment 3.

[0054] In Embodiment 3, the downstream arm 15-2 is equipped with a contact sensor (on its inner surface), and when the controller 46 detects that the contact sensor has come into contact with the article 101, the arm drive system 43 moves the arm 15-2 from the transport path to the automated guided vehicle 1, thereby moving the article 101 together with the arm 15-2 and storing the article 101 in the storage section (upper surface 11b).

[0055] Furthermore, the other configurations and operations of the automated guided vehicle system and automated guided vehicle according to Embodiment 3 are the same as those of Embodiments 1 or 2, so their description will be omitted.

[0056] Embodiment 4.

[0057] In Embodiment 4, the controller 46 uses a machine learning model trained using an existing method to perform object detection processing on the captured image described above and detects that the article 101 is in contact with the arm 15-2. When the controller 46 detects that the arm 15-2 has come into contact with the article 101 through object detection processing, the arm drive system 43 moves the arm 15-2 from the transport path to the automated guided vehicle 1, thereby moving the article 101 together with the arm 15-2 and storing the article 101 in the storage section (upper surface 11b).

[0058] Furthermore, the controller 46 may use a machine learning model trained using existing methods to perform object detection processing on the captured image described above, and may detect when the arm 15-2 (position) overtakes the item 101 while the automated guided vehicle 1 is traveling parallel to the item 101.

[0059] Furthermore, the other configurations and operations of the automated guided vehicle system and automated guided vehicle according to Embodiment 4 are the same as those of Embodiments 1 or 2, so their description will be omitted.

[0060] Furthermore, various changes and modifications to the embodiments described above will be obvious to those skilled in the art. Such changes and modifications may be made without deviating from the spirit and scope of the subject matter and without diminishing the intended advantages. In other words, such changes and modifications are intended to be included in the claims.

[0061] For example, in the above embodiment 1, the upstream rail 14-1 and arm 15-1 may not be provided.

[0062] Furthermore, in Embodiment 1, if sufficient friction is generated at the contact point between the arm 15-2 and the article 101, and the article 101 moves to the storage section together with the arm 15-2 due to that friction when the arm 15-2 is retracted, then the claw portion 21 does not need to be provided.

[0063] Furthermore, in embodiments 1 and 2 described above, when the article 101 is held in place by only the downstream arm 15-2, the upstream arm 15-1 may be configured to restrict the rotation of the article 101 when it is moved together with the arm 15-2. In this case, for example, with the claw portion 21 of the upstream arm 15-1 retracted, the arm 15-1 may protrude by a shorter distance than the downstream arm 15-2. As a result, even if the article 101 attempts to rotate due to contact between the claw portion 21 of the downstream arm 15-2 and the article 101, the article 101 will remain in contact with the upstream arm 15-1, thus preventing the article 101 from rotating much at all.

[0064] The present invention can be applied, for example, to automated guided vehicles.

Claims

1. An automated guided vehicle (AGV) that travels along a predetermined travel path and transports an article being transported along a predetermined transport path, comprising: a travel drive system that drives the AGV along the travel path; a storage section in which the article is stored; an arm located downstream of the storage section in the travel path; an arm drive system that moves the arm from the AGV onto the transport path and moves the arm from the transport path back to the AGV; and a controller that controls the travel drive system and the arm drive system, wherein the controller (a) moves the arm from the AGV onto the transport path using the arm drive system, and (b) when the AGV is traveling parallel to the article, moves the arm from the transport path back to the AGV using the arm drive system while the AGV is in contact with the article by lowering the travel speed of the AGV to a speed lower than the transport speed of the article, thereby moving the article together with the arm and storing the article in the storage section.

2. The unmanned transport vehicle according to claim 1, further comprising a claw drive system, wherein the arm is provided with a retractable claw portion at the tip of the arm, the claw drive system extends and retracts the claw portion, and the controller (a) extends the claw portion with the claw drive system, and (b) with the arm in contact with the article, moves the arm from the transport path to the unmanned transport vehicle with the arm drive system, thereby moving the article together with the arm while bringing the article into contact with the claw portion and storing the article in the storage section.

3. The vehicle further comprises an upstream arm located upstream of the housing in the travel path, the downstream arm having a retractable claw portion at the tip of the upstream arm, the claw drive system retracts the claw portion of the arm and the claw portion of the upstream arm, the arm drive system moves the upstream arm from the automated guided vehicle onto the transport path and moves the upstream arm from the transport path back to the automated guided vehicle. The controller (a) identifies the weight of the article, (b) if the identified weight is less than or equal to a predetermined first threshold, (b1) moves the upstream arm from the automated guided vehicle onto the transport path using the arm drive system, (b2) extends the claw portion of the arm and the claw portion of the upstream arm using the claw drive system, and (b3) with the arm in contact with the article, moves the arm and the upstream arm from the transport path onto the automated guided vehicle using the arm drive system, thereby bringing the article into contact with the claw portion of the arm and the claw portion of the upstream arm. The automated guided vehicle according to claim 2, characterized in that (c) if the specified weight exceeds the first threshold, without using the upstream arm, (c1) the arm drive system moves the arm from the automated guided vehicle to the transport path, and (c2) the arm drive system moves the arm from the transport path to the automated guided vehicle with the arm in contact with the article, thereby moving the article together with the arm and storing the article in the storage section.

4. The unmanned transport vehicle according to claim 1, characterized in that the controller (a) identifies the weight of the article, and (b) adjusts the travel speed according to the identified weight.

5. The unmanned transport vehicle according to claim 4, characterized in that (a) if the specified weight is less than a predetermined first threshold or exceeds a predetermined second threshold, the travel speed when the arm is in contact with the article is a predetermined first speed, and (b) if the specified weight is greater than or equal to the first threshold and less than or equal to the second threshold, the travel speed when the arm is in contact with the article is a second speed lower than the first speed.

6. The unmanned transport vehicle according to claim 1, characterized in that the arm is equipped with a contact sensor, and when the controller detects that the contact sensor has come into contact with the article, the arm drive system moves the arm from the transport path to the unmanned transport vehicle, thereby moving the article together with the arm and storing the article in the storage section.

7. The unmanned transport vehicle according to claim 1, further comprising an imaging device that images the area in front of the storage section and generates an image, wherein the controller acquires the image, performs object detection processing on the image, and detects that the article is in contact with the arm.

8. The unmanned transport vehicle according to claim 1, further comprising an upstream arm located upstream of the storage section in the travel path, wherein the upstream arm restricts the rotation of the article when the article is moved together with the arm.

9. An automated guided vehicle system characterized by comprising: an automated guided vehicle according to claim 1; and a conveyor for transporting the articles along the transport route.

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