Unmanned transport vehicle

Abstract

A controller (46) controls a travel drive system (42) and an arm drive system (43) so that an unmanned transport vehicle travels and an article is collected by means of an arm. In particular, the controller (46) determines, in accordance with the type of the article, whether to collect the article by means of the arm while allowing the unmanned transport vehicle to travel, or to collect the article by means of the arm in a state in which the unmanned transport vehicle is stopped.

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 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 on a conveyor, (b) extends the arm on the upstream side of the travel route, 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] Specification of Patent No. 7448894

[0004] When the relative speed of the automated guided vehicle with respect to the article is high, the above-described automated guided vehicle may cause the article to be damaged due to contact of the arm 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 due to contact of an arm with 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 articles, and includes a travel drive system that causes the automated guided vehicle to travel along the travel route, a storage unit in which the articles are 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 with the arm. Then, the controller determines whether to accommodate the article with the arm while causing the automated guided vehicle to travel or to accommodate the article with the arm in a state where the automated guided vehicle is stopped, according to the type of the article.

[0007] According to the present invention, an automated guided vehicle that suppresses the possibility of an article being damaged due to contact of the article with the arm 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 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 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 it is receiving an item 101 while moving (1 / 2). Figure 7 is a diagram illustrating the operation of the AGV 1 when it is receiving an item 101 while moving (2 / 2). Figure 8 is a diagram illustrating the operation of the AGV 1 when it is stopped and receiving an item 101 (1 / 2). Figure 9 is a diagram illustrating the operation of the AGV 1 when it is stopped and receiving an item 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 make the unmanned transport vehicle 1 move in a straight line or 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 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. 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 a predetermined direction (the direction of movement of arms 15-1 and 15-2, in this case, laterally to the travel direction) of the housing (upper surface 11b) and generates an image.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] The communication device 45 communicates with an external server (not shown) via wireless communication or other means.

[0023] 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.

[0024] Furthermore, the controller 46 determines, depending on the type of item 101, whether to pick up the item 101 with the arm 15-i while the automated guided vehicle 1 is in motion, or to pick up the item 101 with the arm 15-i while the automated guided vehicle 1 is stopped.

[0025] For example, the controller 46 may identify the type of article 101 by reading and decoding a visible code attached to the article 101, as described later, or it may use a communication device 45 to receive notification of the type of article 101 from a server (not shown).

[0026] Furthermore, in this embodiment, when the controller 46 decides to pick up an item 101 with the arm 15-i while the automated guided vehicle 1 is moving, it sets the travel speed of the automated guided vehicle 1 when picking up the item 101 with the arm 15-i, according to the type of item 101. Here, the travel speed of the automated guided vehicle 1 when picking up the item 101 with the arm 15-i is set to either the standard speed or a slow speed lower than the standard speed.

[0027] In this embodiment, the types of articles 101 include a first type that should be avoided due to vibration or shock, and a second type other than the first type. For example, if article 101 is fragile or a precision instrument, the type of article 101 is the first type.

[0028] In this embodiment, the controller 46 decides to store the article 101 with the arm 15-i while the automated guided vehicle 1 is stopped if the article 101 is of the first type, and decides to store the article 101 with the arm 15-i while the automated guided vehicle 1 is running if the article 101 is of the second type.

[0029] In this embodiment, the controller 46 controls the arm drive system 43 to move the unmanned transport vehicle 1 in a predetermined direction, and when the upstream arm 15-1 of the two arms 15-1 and 15-2 comes into contact with the article 101, the controller 46 moves the downstream arm 15-2 of the two arms 15-1 and 15-2 in a predetermined direction, and the two arms 15-1 and 15-2 pick up the article 101.

[0030] Specifically, when the automated guided vehicle 101 is moving and the arm 15-i is receiving the item 101, the controller 46 (a) controls the arm drive system 43 while the automated guided vehicle 101 is moving at a standard speed to move the upstream arm 15-1 away from the automated guided vehicle 1 towards the storage rack 2 (perpendicular to the direction of travel), and (b) when the arm 15-1 comes into contact with the item 101, the controller 46 controls the arm 15-i together with the automated guided vehicle 101 while the automated guided vehicle 101 is moving. (c) The arm drive system 43 is controlled to move the arm 15-2 from the automated guided vehicle 1 toward the storage shelf 2 while moving the article 101 along the direction of travel, (c) the claw drive system 44 extends the claw portions 21 of the arms 15-1 and 15-2, and the arm drive system 43 returns the arms 15-1 and 15-2 toward the automated guided vehicle 1, thereby moving the article 101 together with the arms 15-1 and 15-2 while bringing the article 101 into contact with the claw portions 21, and storing the article 101 in the storage section (upper surface 11b).

[0031] On the other hand, when the automated guided vehicle 1 is stopped and the arm is to pick up the item 101, the controller 46 (a) moves the automated guided vehicle 101 at a slow speed and moves the arm 15-1 from the automated guided vehicle 1 toward the storage shelf 2 using the arm drive system 43, (b) stops the automated guided vehicle 101 when the arm 15-1 comes into contact with the item 101, and (c) controls the arm drive system 43 to move the arm 15-2 while the automated guided vehicle 101 is stopped. (d) The automated guided vehicle 101 is moved toward the storage shelf 2, (e) with the automated guided vehicle 101 stopped, the claw drive system 44 extends the claw portions 21 of arms 15-1 and 15-2, and with the automated guided vehicle 101 stopped, the arm drive system 43 returns arms 15-1 and 15-2 to the automated guided vehicle 1, thereby moving the article 101 together with arms 15-1 and 15-2 while bringing the article 101 into contact with the claw portions 21, and storing the article 101 in the storage section (upper surface 11b). Note that when storing the article 101 with the arms while the automated guided vehicle 1 is stopped, the controller 46 may set the movement speed of arms 15-1 and 15-2 to be lower than when storing the article 101 with arm 15-i while the automated guided vehicle 101 is running.

[0032] 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 it is receiving the goods 101 while moving. Figures 8 and 9 illustrate the operation of the automated guided vehicle 1 when it is stopped and receiving the goods 101.

[0033] 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 a communication device 45, for example from a server (not shown), 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).

[0034] Furthermore, the controller 46 controls the arm drive system 43 to move the upstream arm 15-1 along the rail 14-1 in a predetermined direction (towards the storage shelf 2), and controls the claw drive system 44 to extend the claw portion 21 of the upstream arm 15-1. At this point, the controller 46 does not move the downstream arm 15-2 in a predetermined direction (towards the storage shelf 2).

[0035] Then, when the controller 46 detects the visible code 101a (in this case, a two-dimensional code) attached to the item 101 in the captured image, it decodes the visible code 101a to obtain identification information and type information of the item 101 and identifies the type of item 101 (step S2). Alternatively, the above command may be used to notify the automated guided vehicle 1 of the type of item 101.

[0036] When the controller 46 identifies the type of item 101, it determines whether or not to set the travel speed of the automated guided vehicle 1 to a slow speed based on the type of item 101 (step S3).

[0037] If the controller determines that the travel speed of the automated guided vehicle 1 should not be reduced to a slow speed, the controller 46 controls the arm drive system 43 while the automated guided vehicle 101 travels at a standard speed (step S4), moving the upstream arm 15-1 away from the automated guided vehicle 1 towards the storage rack 2 (perpendicular to the travel direction). When the arm 15-1 makes contact with the item 101, the controller controls the arm 15-1 and the item 101 in the travel direction while the automated guided vehicle 101 is still traveling. While moving along the curve, the arm drive system 43 is controlled to move arm 15-2 from the automated guided vehicle 1 towards the storage shelf 2, the claw drive system 44 extends the claw portions 21 of arms 15-1 and 15-2, and the arm drive system 43 returns arms 15-1 and 15-2 to the automated guided vehicle 1, thereby moving the article 101 together with arms 15-1 and 15-2 while bringing the article 101 into contact with the claw portions 21, and storing the article 101 in the storage section (upper surface 11b) (step S5).

[0038] Furthermore, contact between the arm 15-1 and the article 101 may be detected, for example, based on the position of the visible code 101a in the captured image, or it may be detected based on the captured image using object detection technology that employs machine learning.

[0039] After storing the article 101 in this manner, the automated guided vehicle 1 travels along its route to the destination (in this case, a predetermined position on the storage shelf 3). When the automated guided vehicle 1 arrives at the destination, the controller 46 extends the claw portions 22 at the rear ends of the arms 15-1 and 15-2 using the claw drive system 44, and then moves the arms 15-1 and 15-2 forward (to the predetermined position on the storage shelf 3) using the arm drive system 43, pushing the article 101 into contact with the claw portions 22 and moving the article 101 to the predetermined position on the storage shelf 3 (step S6).

[0040] On the other hand, if in step S3 it is determined that the travel speed of the automated guided vehicle 1 should be reduced to a slow speed, the controller 46 immediately makes the automated guided vehicle 1 travel at a slow speed (step S7). Furthermore, the controller 46 determines whether or not to stop the automated guided vehicle 1 and store the item based on the type of item 101 (step S8).

[0041] If the controller 46 determines that the automated guided vehicle 1 should not be stopped to store the item, the controller 46 will move the automated guided vehicle 1 at a slow speed, and if it determines that the arm 15-1 has come into contact with the item 101, it will store the item 101 in the same manner as in the case of standard speed (step S5). Subsequently, as described above, the controller 46 will move the automated guided vehicle 1 to the destination and move the item 101 to the storage shelf 3 at the destination (step S6).

[0042] On the other hand, in step S8, when it is determined that the AGV 1 is to be stopped to accommodate the article, if the controller 46 determines that the arm 15-1 has contacted the article 101 while the AGV 1 is traveling at a creep speed, the controller 46 immediately controls the travel drive system 42 to stop the AGV 1. For example, as shown in FIG. 8, the downstream arm 15-2 is moved along the rail 14-1, the claw drive system 44 is controlled to project the claw portion 21 of the arm 15-2, and the arm drive system 43 is controlled to return the arms 15-1 and 15-2 to the AGV 1 along the rails 14-1 and 14-2, for example, as shown in FIG. 9, to accommodate the article 101 (step S9). Thereafter, as described above, the controller 46 drives the AGV 1 to the destination and moves the article 101 to the storage shelf 3 at the destination (step S6).

[0043] After moving the article 101 to the storage shelf 3 at the destination, the controller 46 stores the claw portion 22 with the claw drive system 44, returns the arm 15-1 (or the arms 15-1 and 15-2) to their original positions, and then controls the travel drive system 42 to move the AGV 1 to the home position along the travel route.

[0044] As described above, according to the above embodiment, the controller 46 controls the travel drive system 42 and the arm drive system 43 to accommodate the article 101 with the arm 15-i. In particular, the controller 46 determines whether to accommodate the article 101 with the arm 15-i while the AGV 1 is traveling or to accommodate the article 101 with the arm 15-i while the AGV 1 is stopped, according to the type of the article 101.

[0045] Thereby, for articles that are easily damaged, the article 101 is accommodated in a stopped state, so that the possibility of the article 101 being damaged due to contact with the arm 15-i is suppressed.

[0046] 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.

[0047] For example, in the above embodiment, when storing an item 101 while the automated guided vehicle 101 is traveling at a standard speed, the item 101 may be stored using only the upstream arm 15-1. In that case, when the controller 46 determines that the arm 15-1 has come into contact with the item 101, it immediately returns the arm 15-1 to the automated guided vehicle 1 with the arm drive system 43, thereby moving the item 101 together with the arm 15-1 and storing the item 101 in the storage section (upper surface 11b). At that time, the controller 46 may also extend the claw portion 21 of the arm 15-1 with the claw drive system 44, and move the item 101 together with the arm 15-1 while the item 101 is in contact with the claw portion 21, thereby storing the item 101 in the storage section (upper surface 11b).

[0048] 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 picks up 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; an arm; an arm drive system 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 pick up the goods with the arm, wherein the controller determines, depending on the type of goods, whether to pick up the goods with the arm while the AGV is in motion or to pick up the goods with the arm while the AGV is stopped.

2. The automated guided vehicle according to claim 1, characterized in that when the controller decides to pick up the article with the arm while the automated guided vehicle is in motion, it sets the travel speed of the automated guided vehicle when picking up the article with the arm, according to the type of article.

3. The type of article includes a first type which should be avoided by vibration or shock, and a second type which is other than the first type, the article is stationary, and the controller decides to pick up the article with the arm while the automated guided vehicle is stopped if the type of article is the first type, and decides to pick up the article with the arm while the automated guided vehicle is running if the type of article is the second type, the automated guided vehicle according to claim 1.

4. The automated guided vehicle according to claim 1, comprising two arms including the aforementioned arm, wherein the article is stationary, and the controller controls the arm drive system to move the upstream arm of the two arms in the travel path in the predetermined direction while the automated guided vehicle is traveling, and when the upstream arm comes into contact with the article, the downstream arm of the two arms in the predetermined direction is moved to accommodate the article with the two arms.

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