Unmanned transport vehicle

Abstract

A travel drive system (42) causes an unmanned transport vehicle to travel along a travel path. For each of two arms, an arm drive system (43) moves the arm in a prescribed direction from the unmanned transport vehicle and returns the arm to the unmanned transport vehicle (1). An imaging device (16) images an article (101) and generates a captured image. A controller (46) controls the travel drive system (42) and the arm drive system (43) to accommodate the article (101). On the basis of the captured image, the controller (46) selects, from among the two arms, the arm that accommodates the article (101).

Description

Automated guided vehicle

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

[0002] A certain automated guided vehicle includes two arms each having a claw portion that can be extended and retracted at each tip, and (a) travels parallel to the conveyance direction of an article being conveyed by a conveyor at a speed higher than the conveyance speed of the article, (b) extends the arm on the upstream side of the travel route, and when the upstream arm has moved to the position of the article, extends the downstream arm, (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

[0004] However, when the article is contained in a packaging material such as a cardboard box or a case, and its outer peripheral surface is wet and softened or has a notch or dent, the above-described automated guided vehicle may cause the article to be damaged due to contact of the arm or claw portion with the article.

[0005] The present invention has been made in view of the above problems, and an object thereof is to obtain an automated guided vehicle that suppresses the possibility of an article being damaged when the article is accommodated.

[0006] The automated guided vehicle according to the present invention is an automated guided vehicle that travels along a predetermined travel route and accommodates and conveys an article, and includes a travel drive system that causes the automated guided vehicle to travel along the travel route, a storage unit in which the article is stored, two arms disposed at both end portions of the storage unit, for each of the two arms, an arm drive system that moves the arm in a predetermined direction from the automated guided vehicle and returns the arm to the automated guided vehicle, an imaging device that images the article and generates an imaging image, and a controller that controls the travel drive system and the arm drive system to accommodate the article. Then, the controller selects, based on the imaging image, the arm that accommodates the article among the two arms.

[0007] According to the present invention, an automated guided vehicle that suppresses the possibility of an article being damaged when the article is accommodated can be obtained.

[0008] 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.

[0009] Figure 1 is a diagram illustrating the configuration of an automated guided vehicle (AGV) system including an AGV 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 flowchart illustrating the operation of the AGV 1 shown in Figure 2. Figure 6 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up with only one arm (1 / 2). Figure 7 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up with only one arm (2 / 2). Figure 8 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up with both arms (1 / 2). Figure 9 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up with both arms (2 / 2).

[0010] Embodiments of the present invention will be described below with reference to the figures.

[0011] Figure 1 is a diagram showing the configuration of an automated guided vehicle (AGV) system including an AGV according to an embodiment of the present invention. The AGV system shown in Figure 1 comprises an AGV 1, a storage rack 2 which is the source of the article 101, and a storage rack 3 which is the destination of the article 101. In this embodiment, the article 101 is placed on the storage rack 2 and is stationary. The AGV 1 travels along a predetermined route, picks up the article 101 from the storage rack 2, transports it, and delivers the article 101 to the storage rack 3.

[0012] The travel route, the location of the transport source, and the location of the transport destination may be set virtually by the automated guided vehicle 1 or a server (not shown) (i.e., by floor patterns unique to each location without placing markers or other components), or they may be set physically by markers or other components. The aforementioned travel route partially runs parallel to the storage shelves 2 and 3, and in this parallel section, the articles 101 are stored from the storage shelves 2 to the automated guided vehicle 1 and placed from the automated guided vehicle 1 to the storage shelves 3.

[0013] Furthermore, item 101 is placed in packaging materials or cases such as cardboard boxes, and has a roughly rectangular parallelepiped shape in appearance.

[0014] 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.

[0015] 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.

[0016] 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 and are arranged on rails 14-1 and 14-2. Arms 15-1 and 15-2 are also arranged at both ends of the housing section (upper surface 11b). 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. If the direction of travel is reversed, arm 15-1 becomes the downstream arm, and arm 15-2 becomes the upstream arm.

[0017] 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).

[0018] Furthermore, the imaging device 16 is equipped with an image sensor such as a CCD (Charge Coupled Device) and captures an image of the housing section (upper surface 11b) in a predetermined direction (the direction of movement of arms 15-1 and 15-2, in this case, laterally to the travel direction) at a predetermined angle of view and generates an image. If the article 101 is within that angle of view, the image of the article 101 is included in the image.

[0019] In the case shown in Figure 2, the imaging device 16 is positioned on the upper surface 11b, but the imaging device 16 may also be positioned on the upper surface 11b, outside of the arms 15-1 and 15-2, respectively.

[0020] As described later, the imaging device 16 is used to image the side of the article 101 in order to determine the condition of the side of the article 101, or to read the visible code attached to the article 101.

[0021] 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.

[0022] 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.

[0023] The arm drive system 43 moves the arm 15-i (i=1,2) away from the automated guided vehicle 1 in a predetermined direction and returns the arm 15-i to the automated guided vehicle 1.

[0024] The communication device 45 communicates with an external server (not shown) via wireless communication or other means.

[0025] 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 automated guided vehicle 1, retrieve the items 101 from the storage shelf 2, and place the items 101 on the storage shelf 3.

[0026] In particular, the controller 46 selects one of the two arms 15-1 and 15-2 to accommodate the article 101 based on the image captured by the imaging device 16.

[0027] Furthermore, in this embodiment, the controller 46 (a) is equipped with a machine learning learner (such as a convolutional neural network), which takes the captured image as input and uses the learner to determine the state of the side (for example, a binary value of good and bad), and (b) based on the state of the side, selects one of the two arms 15-1 and 15-2 to accommodate the article 101. The aforementioned side is the surface that the arms 15-1 and 15-2 make contact with when used to accommodate the article.

[0028] Specifically, the arm corresponding to the side determined to be in good condition (on that side) is selected as the arm that will hold the article 101, and the arm corresponding to the side determined to be in poor condition (on that side) is not selected as the arm that will hold the article 101.

[0029] This learning machine is trained using existing methods based on training data containing images of various objects. In this training data, the input images of objects include those with wet and discolored sides, or those with abnormal shapes such as notches or dents on the sides, and such objects are considered to be in poor condition in the output data. However, the training data also includes images of objects without such discoloration or abnormal shapes, and such objects are considered to be in good condition in the output data.

[0030] Furthermore, in this embodiment, the controller 46 controls the claw drive system 44 and, based on the captured image, determines whether or not to accommodate the article 101 with the claw portion 21 protruding (that is, while the claw portion 21 is in contact with the article 101).

[0031] For example, the controller 46 uses a machine learning-trained learner to determine the state of the area on the article 101 that the claw portion 21 contacts when the claw portion 21 is extended, and based on that state, it determines whether or not to accommodate the article 101 with the claw portion 21 extended.

[0032] Furthermore, if the controller 46 selects only one of the two arms 15-1 and 15-2 as the arm for receiving the item 101, it will receive the item with the selected arm while the automated guided vehicle 1 is in motion. At that time, the controller 46 will move the automated guided vehicle 1 so that the selected arm becomes the upstream arm.

[0033] In particular, in this embodiment, when the controller 46 selects only one of the two arms 15-1 and 15-2 as the arm for receiving the article 101, it determines, based on the captured image described above, whether or not to receive the article 101 with the claw drive system 44 extending the claw portion 21. In this case, the travel speed of the automated guided vehicle 1 when receiving the article 101 with the claw portion 21 not extended is set higher than the travel speed of the automated guided vehicle 1 when receiving the article 101 with the claw portion 21 extended. This increases the friction between the article 101 and the arm, making it easier to receive the article 101 with the arm.

[0034] Next, the operation of the automated guided vehicle 1 described above will be explained. Figure 5 is a flowchart illustrating the operation of the automated guided vehicle 1 shown in Figure 2. Figures 6 and 7 illustrate the operation of the automated guided vehicle 1 when the item 101 is picked up using only one arm. Figures 8 and 9 illustrate the operation of the automated guided vehicle 1 when the item 101 is picked up using both arms.

[0035] The automated guided vehicle 1 is stationary and waiting at its home position (the position shown in Figure 1). When the controller 46 receives a command from, for example, a server (not shown) via a communication device 45, it controls the drive system 42 to make the automated guided vehicle 1 travel along the travel path at a standard speed and monitors the images captured by the imaging device 16 (step S1).

[0036] The controller 46 uses the aforementioned learning device to detect one and the other side of the article 101 in the captured image (a surface substantially perpendicular to the direction of travel) and determines the state of that side. At this time, the controller 46 moves the automated guided vehicle 1 so that both sides are sequentially within the field of view of the imaging device 16. Alternatively, for example, two imaging devices 16 may be provided on the outside of the arms 15-1 and 15-2, and the controller 46 may stop the automated guided vehicle 1 facing the article 101 and capture both sides together with the two imaging devices 16.

[0037] Then, the controller 46 determines whether or not to accommodate the item 101 with only one arm, based on the determination result of the side condition (step S3).

[0038] If it is determined that the article 101 will be held in place by only one arm, the controller 46 identifies the arm that will hold the article 101 and, based on the side view image, determines whether or not to extend the claw portion 21 of the arm that will hold the article 101 (step S4).

[0039] If the controller 46 determines that the claw portion 21 should be extended, it moves the arm that holds the article 101 along the corresponding rail toward the article 101 (i.e., to the side substantially perpendicular to the direction of travel), as shown in Figure 6, for example, and extends the claw portion 21 (step S5).

[0040] The controller 46 then controls the travel drive system 42 to make the automated guided vehicle 1 travel at a standard speed so that the arm that holds the item 101 becomes the upstream arm. If the controller 46 determines, for example, based on the position of the visible code 101a in the captured image, that the selected arm 15-1 is in contact with the item 101, then, for example as shown in Figure 7, it controls the arm drive system 43 to return the arm to the automated guided vehicle 1 along the corresponding rail and hold the item 101 (step S6).

[0041] Specifically, at this time, since the article 101 is in contact with the arm 15-1 and the claw portion 21, while moving along the traveling direction together with the arm 15-1, it moves to the accommodating portion (upper surface 11b) of the driverless transport vehicle 1 together with the arm 15-1. Here, for example, as shown in FIGS. 6 and 7, the arm 15-1 and the claw portion 21 come into contact with the side surface of the article 101 determined to be in good condition. On the other hand, for example, the arm 15-2 and the claw portion 21 are not brought into contact with the side surface 101b of the article 101 that is wet and in poor condition.

[0042] For example, when the article 101 comes into contact with the arm 15-1 and the article 101 moves at the same speed as the driverless transport vehicle 1 so that the position of the visible code 101a in the captured image hardly changes, it is determined that the arm 15-1 is in contact with the article 101.

[0043] After accommodating the article 101 in this way, the driverless transport vehicle 1 travels along the travel route to the transport destination (here, a predetermined position of the storage shelf 3) (step S7). The transport destination is specified, for example, in a database or a server based on the identification information of the article 101.

[0044] When the driverless transport vehicle 1 arrives at the transport destination, the controller 46 projects the claw portion 22 with the claw drive system 44 and stores the claw portion 21, and then moves the arms 15-1 and 15-2 forward (to the predetermined position of the storage shelf 3) with the arm drive system 43, and moves the article 101 to the predetermined position of the storage shelf 3 while pushing the article 101 while bringing the claw portion 22 into contact with the article 101. After that, the controller 46 stores the claw portion 22 with the claw drive system 44, returns the arms 15-1 and 15-2 to their original positions, and then controls the travel drive system 42 to move the driverless transport vehicle 1 to the home position along the travel route.

[0045] On the other hand, if in step S4 it is determined that the claw portion 21 of the arm that holds the article 101 should not be extended, the controller 46 controls the travel drive system 42 with the claw portion 21 retracted so that the automated guided vehicle 1 travels at a speed higher than the standard speed so that the arm that holds the article 101 becomes the upstream arm. If it is determined that the arm 15-1 is in contact with the article 101, as in the case described above, the arm is returned to the automated guided vehicle 1 to hold the article 101 (step S6). After that, the automated guided vehicle 1 similarly transports the article 101 to the destination (in this case, a predetermined position on the storage shelf 3) (step S7) and returns to the home position.

[0046] On the other hand, in step S3, if it is determined that the article 101 will not be accommodated with only one arm (i.e., the article 101 will be accommodated with both arms 15-1 and 15-2), the controller 46 stops the automated guided vehicle 1 facing the article 101, as shown in Figure 8, for example, and moves both arms 15-1 and 15-2 to a position to the side of the article 101 using the arm drive system 43, causing the claw portions 21 of both arms 15-1 and 15-2 to protrude. Then, as shown in Figure 9, for example, both arms 15-1 and 15-2 are returned to accommodate the article 101 (step S8). At this time, since the article 101 is in contact with the arms 15-1 and 15-2 and the claw portions 21 on the side that is determined to be in good condition, it moves together with arm 15-1 to the accommodation section (upper surface 11b) of the automated guided vehicle 1. Subsequently, the automated guided vehicle 1 similarly transports the item 101 to its destination (in this case, a predetermined position on the storage shelf 3) (step S7), and returns to its home position.

[0047] As described above, according to the above embodiment, the traveling drive system 42 causes the unmanned transport vehicle 1 to travel along the traveling route. The arm drive system 43 moves each of the two arms 15-1 and 15-2 in a predetermined direction from the unmanned transport vehicle 1 and returns the arms to the unmanned transport vehicle 1. The imaging device 16 images the article 101 and generates an image. The controller 46 controls the traveling drive system 42 and the arm drive system 43 to accommodate the article 101. Then, the controller 46 selects, based on the captured image, the arm that accommodates the article 101 from the two arms 15-1 and 15-2.

[0048] Thereby, based on the captured image showing the appearance of the article 101, an arm or the like that contacts the article 101 during accommodation is selected, and the arm or the like does not contact a portion where the article is likely to be damaged. Therefore, the possibility of the article being damaged during accommodation is suppressed.

[0049] Various changes and modifications to the above-described embodiment will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing the intended advantages. That is, such changes and modifications are intended to be included in the claims.

[0050] For example, in the above embodiment, when the states of both side surfaces of the article 101 are defective, an error notification may be made without accommodating the article 101.

[0051] The present invention is applicable, for example, to an unmanned transport vehicle.

Claims

1. An automated guided vehicle (AGV) that travels along a predetermined travel path and transports goods, comprising: a travel drive system that drives the AGV along the travel path; a storage section in which the goods are stored; two arms positioned at both ends of the storage section; an arm drive system for each of the two arms that moves the arm away from the AGV in a predetermined direction and returns the arm to the AGV; an imaging device that images the goods and generates an image; and a controller that controls the travel drive system and the arm drive system to store the goods, wherein the controller selects one of the two arms to store the goods based on the image.

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 retracts the claw portion, and the controller controls the claw drive system to determine, based on the captured image, whether or not to accommodate the article with the claw portion extended.

3. The automated guided vehicle according to claim 1, characterized in that the captured image includes an image of the side of the article, and the arm for receiving the article contacts the side when receiving the article.

4. The unmanned transport vehicle according to claim 3, characterized in that the controller (a) comprises a machine learning-trained learner, which determines the state of the side using the captured image as input, and (b) selects one of the two arms to accommodate the article based on the state of the side.

5. The unmanned transport vehicle according to claim 1, characterized in that when the controller selects only one of the two arms as the arm for receiving the article, it receives the article with the arm while the unmanned transport vehicle is in motion.

6. The automated guided vehicle according to claim 5, characterized in that, when the controller selects only one of the two arms as the arm for receiving the article, it determines, based on the captured image, whether or not to receive the article with the claw portion extended by the claw drive system, and the travel speed of the automated guided vehicle when receiving the article with the claw portion not extended is higher than the travel speed of the automated guided vehicle when receiving the article with the claw portion extended.

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