Unmanned transport vehicle

Abstract

A travel drive system (42) causes an unmanned transport vehicle (1) to travel along a travel route. An arm drive system (43) causes an arm to move in a prescribed direction from the unmanned transport vehicle (1) and returns the arm to the unmanned transport vehicle (1). A controller (46) controls the travel drive system (42) and the arm drive system (43) to accommodate articles. The controller (46) causes the unmanned transport vehicle (1) to travel by controlling the travel drive system (42) such that the arm is positioned on the upstream side of an accommodation part in the travel direction, and accommodates the article using the arm while causing the unmanned transport vehicle (1) to travel at a travel speed that corresponds to the width of a gap on the downstream side of the article. The travel speed is set higher as the width of the gap on the downstream side increases.

Description

Automated guided vehicle

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

[0002] One automated guided vehicle includes two arms each having a claw portion that can be extended and retracted at its 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 path, and extends the arm on the downstream side 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] Japanese Patent No. 7448894

[0004] The above-described automated guided vehicle extends the two arms in order for drawing in an article, and then projects the claw portion and draws in the article into the automated guided vehicle with the two arms. Therefore, the time required to accommodate 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 that shortens the time required to accommodate an article into 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 path, accommodates and conveys an article, and includes a travel drive system that causes the automated guided vehicle to travel along the travel path, a storage portion in which the article is stored, an arm, 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. Then, the controller (a) controls the travel drive system so that the arm is positioned upstream of the storage portion in the travel direction and causes the automated guided vehicle to travel, and (b) accommodates the article with the arm while causing the automated guided vehicle to travel at a travel speed corresponding to the width of the gap on the downstream side of the article. Here, the travel speed is set higher as the width of the gap on the downstream side is wider.

[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 showing 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 showing the electrical configuration of the AGV 1 shown in Figure 2. Figure 5 is a diagram illustrating the correspondence between the gap width downstream of the article 101 and the travel speed Va when the article 101 is stored (1 / 2). Figure 6 is a diagram illustrating the correspondence between the gap width downstream of the article 101 and the travel speed Va when the article 101 is stored (2 / 2). Figure 7 is a flowchart illustrating the operation of the AGV 1 shown in Figure 2. Figure 8 is a diagram illustrating the operation of the AGV 1 when storing the article 101 with only one arm while traveling (1 / 2). Figure 9 is a diagram illustrating the operation of the AGV 1 when storing the article 101 with only one arm while traveling (2 / 2). Figure 10 illustrates the operation of the automated guided vehicle 1 when it is stopped and receiving the item 101 with both arms (1 / 2). Figure 11 illustrates the operation of the automated guided vehicle 1 when it is stopped and receiving the item 101 with both arms (2 / 2).

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

[0011] Embodiment 1.

[0012] 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.

[0013] 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.

[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 make the unmanned transport vehicle 1 move in a straight line or 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 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.

[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 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 a structure 2a adjacent to the article 101, other articles, etc.

[0020] 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.

[0021] The imaging device 16 is used to determine whether the width of the gaps on both sides of the article 101 (especially the downstream side in the direction of travel) is wide enough 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] The communication device 45 communicates with an external server (not shown) via wireless communication or other means.

[0026] 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.

[0027] Figures 5 and 6 illustrate the relationship between the gap width downstream of the article 101 and the travel speed Va when the article 101 is stored inside.

[0028] In particular, the controller 46 (a) controls the travel drive system 42 to move the automated guided vehicle 1 so that the arm 15-i is positioned upstream of the storage section (upper surface 11b) in the direction of travel, and (b) while moving the automated guided vehicle 1 at a travel speed Va corresponding to the width of the gap G2 downstream of the item 101, the arm 15-i stores the item 101. At this time, the travel speed Va is set higher the wider the gap on the downstream side is. For example, in the case shown in Figure 5, the width of the gap G2 on the downstream side is wider than in the case shown in Figure 6, so the travel speed Va is set higher.

[0029] The wider the gap on the downstream side, the longer the distance the article 101 travels within the gap (distance along the direction of travel), so the travel speed Va is set to a higher value. For example, the travel speed Va may be selected from a predetermined number of speeds according to the width of the gap on the downstream side.

[0030] The width of this gap is the distance between the article 101 and the structure adjacent to the article 101 (such as the columns and walls of the storage rack 2), other articles, etc.

[0031] In this embodiment, the controller 46 sets the travel speed Va based on the captured images described above. For example, the controller 46 includes (a) a machine learning-trained learner (such as a convolutional neural network), and (b) the learner derives the travel speed based on the captured images. This learner is machine learning-trained using existing methods based on training data that includes captured images containing various items and downstream gaps. The captured images as input data in the training data include captured images with various gap widths, and the training data also includes, as output data, values ​​of the travel speed Va corresponding to the gap width of each captured image.

[0032] Furthermore, if the controller 46 determines from captured images or the like that both of the gaps G1 and G2 on both sides of the article 101 are narrow and that even at the lowest predetermined travel speed that can accommodate the article 101, there is not enough width to accommodate the article 101 while the automated guided vehicle 1 is traveling, the controller 46 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.

[0033] 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).

[0034] Next, the operation of the automated guided vehicle 1 described above will be explained. Figure 7 is a flowchart illustrating the operation of the automated guided vehicle 1 shown in Figure 2. Figures 8 and 9 illustrate the operation of the automated guided vehicle 1 when it is moving and picking up the item 101 with only one arm. Figures 10 and 11 illustrate the operation of the automated guided vehicle 1 when it is stopped and picking up the item 101 with both arms.

[0035] 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.

[0036] The controller 46 determines 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 minimum travel speed (step S2). If the gap G2 downstream is wide enough, the controller sets the travel speed Va according to the width of the gap G2 (step S3).

[0037] For example, using the learning device described above, steps S2 and S3 are executed by deriving a travel speed Va corresponding to the width of the gap G2 as described above, and outputting an error if the travel speed Va falls below the minimum travel speed.

[0038] Then, as shown in Figure 8, for example, the controller 46 selects the upstream arm 15-1 and, without using the downstream arm 15-2, moves the arm 15-1 along the rail 14-1 toward the gap G1 using the arm drive system 43, and also extends the claw portion 21. After that, it controls the travel drive system 42 to make the unmanned transport vehicle 1 travel at its travel speed Va. If it determines, for example, based on the position of the visible code 101a in the captured image, that the arm 15-1 is in contact with the item 101, then, as shown in Figure 9, for example, 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 S4).

[0039] 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.

[0040] 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 similarly determines 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 minimum travel speed (step S5). If it determines that the gap G1 on the upstream side is wide enough, the controller 46 reverses the direction of travel (step S6), and then similarly sets the travel speed Va (step S3). While the unmanned transport vehicle 1 travels at the set travel speed Va, the controller 46 accommodates the article 101 with the upstream arm 15-2 at this point, without using the downstream arm 15-1 at this point (step S4).

[0041] On the other hand, for example as shown in Figure 10, if there is a structure 2a such as a wall or column on the upstream side and another item 102 on the downstream side, and it is determined that the gap G2 on the downstream side is not wide enough and the gap G1 on the upstream side is not wide enough, the controller 46 stops the automated guided vehicle 1 as described above, moves both arms 15-1 and 15-2 into the gaps G1 and G2 respectively, and extends the claw portion 21, and then controls the arm drive system 43, for example as shown in Figure 11, to return the arms 15-1 and 15-2 to the automated guided vehicle 1 and store the item 101 (step S7).

[0042] 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) (step S8). The destination is identified, for example, in a database or server based on the identification information of the item 101.

[0043] Then, when the automated guided vehicle 1 arrives at the destination, the controller 46 extends the claw portion 22 with the claw drive system 44 and retracts the claw portion 21, and moves the arms 15-1 and 15-2 forward (to a predetermined position on the storage shelf 3) with the arm drive system 43, 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. After that, the controller 46 retracts the claw portion 22 with the claw drive system 44 and returns the arms 15-1 and 15-2 to their original positions, and then controls the travel drive system 42 to move the automated guided vehicle 1 along the travel path to the home position.

[0044] As described above, according to the first embodiment, the traveling drive system 42 causes the driverless transport vehicle 1 to travel along the traveling path. The arm drive system 43 moves the arm 15-i (i = 1, 2) in a predetermined direction from the driverless transport vehicle 1 and returns the arm 15-i to the driverless transport vehicle 1. The controller 46 controls the traveling drive system 42 and the arm drive system 43 to accommodate the article 101. Then, the controller 46 (a) controls the traveling drive system 42 to cause the driverless transport vehicle 1 to travel so that the arm 15-i is located upstream in the traveling direction with respect to the accommodating portion (upper surface 11b), and (b) while causing the driverless transport vehicle 1 to travel at a traveling speed Va corresponding to the width of the gap on the downstream side of the article 101, the article 101 is accommodated by the arm 15-i. Here, the traveling speed Va is set higher as the width of the gap on the downstream side is wider.

[0045] As a result, depending on the arrangement state of the article 101, the time required to accommodate the article 101 in the driverless transport vehicle 1 is shortened. That is, if the width of the gap on the downstream side of the article 101 is wide, the article 101 is accommodated in the driverless transport vehicle 1 while traveling at a high traveling speed Va, so the accommodation time of the article 101 is shortened.

[0046] Second Embodiment.

[0047] In the second embodiment, the controller 46 (a) selects the arm that becomes the upstream arm from the two arms 15-1 and 15-2 so that the wider gap among the gaps G1 and G2 on both sides of the article 101 is on the downstream side, and controls the traveling drive system 42 to cause the driverless transport vehicle 1 to travel, and (b) while causing the driverless transport vehicle 1 to travel at a traveling speed Va corresponding to the width of the downstream gap among the gaps G1 and G2 on both sides of the article 101, the selected arm accommodates the article 101.

[0048] Note that since other configurations and operations of the driverless transport vehicle according to the second embodiment are the same as those of the first embodiment, the description thereof is omitted.

[0049] As described above, according to the second embodiment, since the driverless transport vehicle 1 accommodates the article 101 using the wider gap, the traveling speed Va at the time of accommodating the article 101 is set high, and the time required to accommodate the article 101 can be shortened.

[0050] 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.

[0051] For example, in embodiments 1 and 2 described above, the upstream gap width is determined when the downstream gap width is insufficient. However, instead, if the downstream gap width is insufficient, the system may immediately stop and accommodate the article 101 with both arms 15-i, as in step S7.

[0052] Furthermore, in embodiments 1 and 2 described above, the controller 46 may, if it determines that the width of the gaps on both sides of the article 101 is not wide enough to insert the arm 15-i, notify an error without storing the article 101.

[0053] Furthermore, in the embodiments 1 and 2 described above, the widths of the gaps G1 and G2 may be measured using a distance measuring device that uses ultrasound or radar instead of the captured images described above, or they may be determined in advance by a server (not shown) based on the placement position of the article 101 and notified from that server to the automated guided vehicle 1.

[0054] Furthermore, in embodiments 1 and 2 described above, when the article 101 is accommodated by only one arm 15-i, if sufficient friction is generated at the contact point between the arm 15-i and the article 101, and the article 101 moves to the accommodating section together with the arm 15-i due to that friction when the arm is retracted, then it is not necessary to protrude the claw portion 21.

[0055] Furthermore, in embodiments 1 and 2 described above, when the article 101 is held in place by only the upstream arm 15-i, the downstream arm 15-i may be configured to restrict the rotation of the article 101 when the article 101 is moved together with the upstream arm 15-i. In this case, for example, with the claw portion 21 of the downstream arm 15-i retracted, the downstream arm 15-i 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 15-i and the article 101, the article 101 will come into contact with the downstream arm 15-i, thus preventing the article 101 from rotating much at all.

[0056] 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 for traveling the AGV along the travel path; a storage section for storing the goods; an arm; an arm drive system for moving the arm away from the AGV in a predetermined direction and returning the arm to the AGV; and a controller for controlling the travel drive system and the arm drive system to store the goods, wherein the controller (a) controls the travel drive system to travel the AGV so that the arm is positioned upstream of the storage section in the travel direction, and (b) stores the goods with the arm while traveling the AGV at a travel speed corresponding to the width of the gap downstream of the goods, the travel speed being set higher the wider the gap downstream is.

2. The unmanned transport 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 sets the travel speed based on the image.

3. The unmanned transport vehicle according to claim 2, characterized in that the controller (a) comprises a machine learning-trained learner, and (b) the learner derives the travel speed based on the captured image.

4. The automated guided vehicle according to claim 1, comprising two arms positioned at both ends of the storage section, including the arm, wherein the arm drive system moves each of the two arms away from the automated guided vehicle in a predetermined direction and returns the arm to the automated guided vehicle, and the controller (a) selects the upstream arm from the two arms such that the wider of the gaps on both sides of the article is on the downstream side, and controls the travel drive system to drive the automated guided vehicle, and (b) while driving the automated guided vehicle at a travel speed corresponding to the width of the downstream gap on both sides of the article, the automated guided vehicle accommodates the article with the selected arm.

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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