Automated guided vehicle

Abstract

A travel drive system (42) of this automated guided vehicle causes the automated guided vehicle to travel along a travel path. With respect to each of two arms (15-1, 15-2), an arm drive system (43) moves the arm from the automated guided vehicle in a predetermined direction and returns the arm to the automated guided vehicle. A controller (46) controls the travel drive system (42) and the arm drive system (43) to accommodate an article. The controller (46) selects one of the two arms (15-1, 15-2) to accommodate the article on the basis of at least one width of a gap on either side of the article.

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 its respective 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 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 accommodate the article in 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 that shortens the time required to accommodate an article in the automated guided vehicle according to the arrangement state of the article.

[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, and 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, and a controller that controls the travel drive system and the arm drive system to accommodate the article. And the controller selects an arm for accommodating the article from the two arms based on at least one of the widths of the gaps on both sides of the article.

[0007] According to the present invention, an automated guided vehicle (AGV) can be obtained that reduces the time required to load articles into the AGV depending on the arrangement of the articles.

[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 diagram illustrating an example where an item is picked up using only one arm (1 / 2). Figure 6 is a diagram illustrating an example where an item is picked up using only one arm (2 / 2). Figure 7 is a diagram illustrating an example where an item is picked up using both arms. Figure 8 is a flowchart illustrating the operation of the AGV 1 shown in Figure 2. Figure 9 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up using only one arm (1 / 2). Figure 10 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up using only one arm (2 / 2). Figure 11 is a diagram illustrating the operation of the AGV 1 when an item 101 is picked up using both arms (1 / 2). Figures 11 and 12 illustrate the operation of the automated guided vehicle 1 when both arms are used to receive the article 101 (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 located approximately in the center of that angle of view, the imaging device 16 captures a predetermined area including the article 101 and generates an image. As a result, the image includes images of the article 101 and the gaps on both sides of it. Here, these gaps are a predetermined range of space between the article 101 and structures, other articles, etc. adjacent to the article 101.

[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] The imaging device 16 is used to determine whether the width of the gaps on both sides of the article 101 is sufficient for the unmanned transport vehicle 1 to accommodate the article 101 while traveling at a predetermined speed, or, as described later, 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 width of at least one of the gaps on both sides of the article 101. The width of this gap is the distance between the article 101 and the adjacent structure (such as the columns and walls of the storage rack 2), other articles, etc.

[0027] In this embodiment, the controller 46 (a) determines, based on the captured image described above, whether the width of the gap is wide enough to accommodate the article 101 while the automated guided vehicle 1 is traveling at a predetermined speed; (b) if it determines that the width of the gap is wide enough to accommodate the article 101 while the automated guided vehicle 1 is traveling at a predetermined speed, it selects one of the arms corresponding to the gap as the arm to accommodate the article; and (c) controls the travel drive system 42 and the arm drive system 43 to move the automated guided vehicle 1 and accommodate the article 101 with one of its arms.

[0028] In this embodiment, the controller 46 (a) is equipped with a machine learning-trained learner (such as a convolutional neural network), and (b) the learner determines, based on the captured image, whether the width of the gap is wide enough to accommodate the article 101 while the unmanned transport vehicle 1 is traveling at a predetermined speed.

[0029] This learning device is machine-learned using existing methods based on training data that includes captured images containing various items and gaps on both sides. The captured images used as input data in the training data include images with various gap widths, and the training data also includes, as output data, a determination result (a binary value of yes or no) of whether the gap width in each captured image is wide enough to accommodate the item 101 while the automated guided vehicle 1 is traveling at a predetermined speed.

[0030] Specifically, if the controller 46 determines that the width of the gap is wide enough to accommodate the article 101 while the automated guided vehicle 1 is traveling at a predetermined speed, the controller 46 will travel the automated guided vehicle 1 in a direction such that the gap is downstream of the article 101, and will select the upstream arm as the arm that will accommodate the article.

[0031] Figures 5 and 6 illustrate an example where an item is held in place using only one arm. Figure 7 illustrates an example where an item is held in place using both arms.

[0032] For example, as shown in Figure 5, if the gap G2 downstream of the article 101 in the initial direction of travel is sufficiently wide, the width of the gap G2 is determined to be wide enough to accommodate the article 101 while the unmanned transport vehicle 1 is traveling, and the upstream arm 15-1 is selected as the arm to accommodate the article 101.

[0033] On the other hand, as shown in Figure 6, for example, if the gap G1 upstream of the article 101 in the initial travel direction is sufficiently wide, the width of the gap G1 is determined to be wide enough to accommodate the article 101 while the automated guided vehicle 1 is traveling, the travel direction of the automated guided vehicle 1 is reversed, and the upstream arm 15-2 at that point is selected as the arm that accommodates the article 101.

[0034] On the other hand, as shown in Figure 7, for example, if the gaps G1 and G2 on both sides of the article 101 (the distance between the article 101 and the structure 2a or other article 102) are both narrow and the controller determines that the width of the gaps G1 and G2 on both sides of the article 101 is not wide enough to accommodate the article 101 while the automated guided vehicle 1 is in motion, the controller 46 selects both of the two arms 15-1 and 15-2 as arms to accommodate the article 101, controls the travel drive system 42 and the arm drive system 43 to stop the automated guided vehicle 1 facing the article 101, and then accommodates the article 101 with the two arms 15-1 and 15-2.

[0035] Furthermore, in this embodiment, the controller 46 controls the claw drive system 44 to store the article 101 with the claw portion 21 of the arm used to store the article 101 protruding (that is, with the claw portion 21 in contact with the article 101).

[0036] Next, the operation of the automated guided vehicle 1 described above will be explained. Figure 8 is a flowchart illustrating the operation of the automated guided vehicle 1 shown in Figure 2. Figures 9 and 10 illustrate the operation of the automated guided vehicle 1 when the item 101 is picked up using only one arm. Figures 11 and 12 illustrate the operation of the automated guided vehicle 1 when the item 101 is picked up using both arms.

[0037] The automated guided vehicle 1 is stationary and waiting at its home position (for example, the position shown in Figure 1). When the controller 46 receives a command from a server (not shown) via a communication device 45, for example, it controls the drive system 42 to move the automated guided vehicle 1 along the travel path to the source location and acquires an image captured by the imaging device 16 (an image including the article 101 and the gaps on both sides of it) (step S1). The source location may be indicated by a marker, notified by a server, or identified by monitoring the captured image and detecting the visible code 101a of the article 101.

[0038] The controller 46 uses the learning device described above to determine whether the gap G2 downstream of the article 101 in the current direction of travel is wide enough to accommodate the article 101 while traveling at a predetermined speed (step S2).

[0039] If the controller determines that the gap G2 on the downstream side is of sufficient width, for example as shown in Figure 9, the controller 46 selects the upstream arm 15-1 and moves the arm 15-1 along the rail 14-1 toward the gap G1 with the arm drive system 43 without using the downstream arm 15-2, and also extends the claw portion 21. Then, it controls the travel drive system 42 to move the unmanned transport vehicle 1, and if it determines that the arm 15-1 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 return the arm 15-1 along the rail 14-1 to the unmanned transport vehicle 1 and store the item 101 (step S3).

[0040] For example, when the item 101 comes into contact with the arm 15-1 and the item 101 moves at the same speed as the unmanned transport vehicle 1, and the position of the visible code 101a in the captured image no longer changes substantially, it is determined that the arm 15-1 is in contact with the item 101.

[0041] On the other hand, if the controller 46 determines that the gap G2 on the downstream side in the current direction of travel is not wide enough, the controller 46 uses the learning device described above to determine whether the gap G1 on the upstream side of the article 101 in the current direction of travel is wide enough to accommodate the article 101 while traveling at a predetermined speed (step S4).

[0042] If the controller determines that the upstream gap G1 is of sufficient width, it reverses the direction of travel (step S5), then selects the upstream arm 15-2 at that point, and without using the downstream arm 15-1 at that point, moves the arm 15-2 along the rail 14-2 toward the gap G2 using the arm drive system 43, and also extends the claw portion 21, and then controls the travel drive system 42 to move the unmanned transport vehicle 1, and if it 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 return the arm 15-2 along the rail 14-2 to the unmanned transport vehicle 1 and store the item 101 (step S3).

[0043] On the other hand, if the controller determines that the downstream gap G2 is not wide enough and the upstream gap G1 is not wide enough, the controller 46 stops the automated guided vehicle 1 as described above, moves both arms 15-1 and 15-2 to the gaps G1 and G2 respectively, as shown in Figure 11, and extends the claw portion 21, and then controls the arm drive system 43 to return the arms 15-1 and 15-2 to the automated guided vehicle 1, as shown in Figure 12, to accommodate the article 101 (step S6).

[0044] After accommodating the article 101 in this manner, the driverless transport vehicle 1 travels along the travel route to the destination (here, a predetermined position in the storage shelf 3) (step S7). Note that the destination is specified in a database, a server, or the like based on, for example, the identification information of the article 101.

[0045] When the driverless transport vehicle 1 arrives at the destination, the controller 46 causes the claw drive system 44 to project the claw portion 22 and retract the claw portion 21, and then moves the arms 15-1 and 15-2 forward (to the predetermined position in the storage shelf 3) by the arm drive system 43, and moves the article 101 to the predetermined position in the storage shelf 3 while pushing the article 101 while contacting the claw portion 22. After that, the controller 46 retracts the claw portion 22 by 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.

[0046] As described above, according to the above embodiment, the travel drive system 42 causes the driverless transport vehicle 1 to travel along the travel route. The arm drive system 43 moves each of the two arms 15-1 and 15-2 in a predetermined direction from the driverless transport vehicle 1 and returns the arms to the driverless transport vehicle 1. The controller 46 controls the travel drive system 42 and the arm drive system 43 to accommodate the article 101. Then, the controller 46 selects an arm for accommodating the article 101 from the two arms 15-1 and 15-2 based on the width of at least one of the gaps on both sides of the article 101.

[0047] Thereby, the time required to accommodate the article 101 in the driverless transport vehicle 1 is shortened according to the arrangement state of the article 101. That is, if there is a gap with a sufficient width on at least one of both sides of the article 101, the article 101 can be accommodated in the driverless transport vehicle 1 with only one arm, so the movement time of the other arm is not required, and the article 101 is immediately accommodated in the driverless transport vehicle 1 when one arm contacts the article 101. Therefore, the time required to accommodate the article 101 in the driverless transport vehicle 1 is shortened.

[0048] Various changes and modifications to the above-described embodiments 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 within the scope of the claims.

[0049] For example, in the above-described embodiment, when the controller 46 determines that the width of the gap on one side of the article 101 is a width that allows the article 101 to be accommodated while the driverless transport vehicle 1 is traveling, (a) it determines whether the width of the gap on the other side of the article 101 is a width that allows the arm to be inserted, and (b1) when it determines that the width of the gap on the other side of the article 101 is a width that allows the arm to be inserted, as described above, it accommodates the article 1 with one arm while the driverless transport vehicle 1 is traveling, and (b2) when it determines that the width of the gap on the other side of the article 101 is not a width that allows the arm to be inserted, it may give an error notification without accommodating the article 101.

[0050] Also, in the above-described embodiment, instead of the above-described captured image, the width of the above-described gap may be measured using a distance measuring device using ultrasonic waves or radar, or may be specified based on the arrangement position of the article 101 by a server not shown in advance and notified from the server to the driverless transport vehicle 1.

[0051] Further, in the above-described embodiment, when accommodating the article 101 with only one arm, if sufficient friction occurs at the contact point between the arm and the article 101 and the article 101 moves to the accommodation part together with the arm when the arm is stored due to that friction, the claw part 21 may not be protruded.

[0052] Furthermore, in the above embodiment, when the article 101 is held in place by only the upstream arm, the downstream arm may be configured to restrict the rotation of the article 101 when it is moved together with the upstream arm. In this case, for example, with the claw portion 21 of the downstream arm retracted, the downstream arm may be extended to protrude a shorter distance than the upstream arm. As a result, even if the article 101 attempts to rotate due to contact between the claw portion 21 of the upstream arm and the article 101, the article 101 will come into contact with the downstream arm, thus preventing the article 101 from rotating much at all.

[0053] 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 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; 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 width of at least one of the gaps on both sides of the goods.

2. The automated guided vehicle according to claim 1, further comprising an imaging device that images a predetermined area including the article and generates an image, wherein the controller (a) determines, based on the image, whether the width of the gap is wide enough to accommodate the article while the automated guided vehicle is in motion; (b) if it is determined that the width of the gap is wide enough to accommodate the article while the automated guided vehicle is in motion, selects one arm corresponding to the gap as the arm for accommodating the article; and (c) controls the travel drive system and the arm drive system to accommodate the article with the one arm while the automated guided vehicle is in motion.

3. The unmanned transport vehicle according to claim 2, characterized in that (a) when the controller determines that the width of the gaps on both sides of the article is not wide enough to accommodate the article while the unmanned transport vehicle is in motion, it selects the two arms as arms for accommodating the article, and (b) controls the travel drive system and the arm drive system to stop the unmanned transport vehicle and then accommodates the article with the two arms.

4. The unmanned transport vehicle according to claim 2, characterized in that the controller (a) comprises a machine learning-trained learner, and (b) the learner determines, based on the captured image, whether the width of the gap is wide enough to accommodate the article while the unmanned transport vehicle is in motion.

5. The unmanned transport vehicle according to claim 1, characterized in that the width of the gap is the distance between the article and a structure or other article adjacent to the article.

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