JP7541237B2 - Automated guided vehicles - Google Patents

Description

The present invention relates to an automated guided vehicle.

In order to automate the movement of goods within facilities such as factories, warehouses, and hospitals, the introduction of automated transport vehicles with automatic loading and unloading is progressing. Due to recent improvements in information processing capabilities and surrounding information gathering technology, autonomous automated transport vehicles are becoming mainstream as opposed to the traditional route-guided type. Furthermore, automated transport vehicles are also being equipped with robotic arms to automate loading and unloading.

In order to improve the transport capacity of an automated guided vehicle equipped with a robot arm, it has been proposed to use an electric cylinder to project the loading platform forward of the automated guided vehicle, position the loading platform directly under the working area of the robot arm, and transfer the load in layers, and then return the loading platform to its home position after the stacking transfer is complete (Patent Document 1), and to provide a pedestal that projects from the side of the robot body and can be raised and lowered in order to stably support the load using the robot arm (Patent Document 2).

Japanese Patent Application Publication No. 6-226657 JP 2012-86310 A

However, there is a limit to how much cargo can be carried by an automated guided vehicle equipped with a conventional robot arm. On the other hand, in factories, warehouses, various facilities, and the like, where the aisle width is limited in order to make effective use of the land, it is difficult for the automated guided vehicle to pass through the aisle when loaded with a large amount of cargo. In other words, simply providing a base section on the robot body as described in Patent Document 2 places limitations on the type of cargo that can be carried when increasing the amount of cargo that can be carried by the robot arm. For example, it is not possible to transport a large amount of stacked blank cardboard sheets. Furthermore, if the amount of cargo that can be carried is increased by enlarging the base section, the automated guided vehicle will have to carry a large amount of cargo in front of it, making it difficult to maneuver, and if the aisle width is narrow, it will be unable to go around corners.

It is also possible to expand the cargo carrying space by moving the platform horizontally using an electric cylinder, as described in Patent Document 1, but this would require a drive source for moving the platform and a drive control device for the platform, making the structure of the automated guided vehicle more complex.

In response to this, the present invention relates to an automated guided vehicle in which a robot arm and a platform are mounted on the vehicle body, which allows for an increase in the load capacity of the platform with a simple structure without providing a drive source for moving the platform itself, and further allows the vehicle to easily pass through narrow, curved passages.

The inventor has come up with the idea that in order to increase the amount of cargo that can be loaded, it is effective to move the loading platform so that the area of the loading platform as viewed from above (in other words, the area of the horizontal surface on which cargo can be placed) is enlarged when loading or unloading compared to when it is empty, in other words, to move the loading platform so that the area of the loading platform as viewed from above is reduced when it is empty compared to when it is loaded or unloaded, by, for example, using a loading platform with two loading surfaces that have an L-shaped cross section, one of which is a wide surface that forms the long side of the L shape in the cross section and the other is a narrow surface that forms the short side of the L shape in the cross section, and keeping the wide surface upright when it is empty, and rotating the loading platform to make the wide surface horizontal when it is loading or unloading, and using the surface formed by the wide surface as the loading surface, and in other words, to move the loading platform so that the area of the loading platform as viewed from above is reduced when it is empty compared to when it is loading or unloading, and in that case, it is possible to solve the above-mentioned problems by not providing a driving source for the loading platform itself, but by moving the loading platform with a robot arm, and thus completed the present invention.

That is, the present invention provides an automated guided vehicle in which a robot arm and a loading platform are mounted on the vehicle body, and the loading platform is configured so that the area of the loading platform as viewed from above can be enlarged or reduced by the robot arm moving the loading platform.

The present invention also provides a method for transporting luggage using an unmanned guided vehicle having a robot arm and a loading platform mounted on the vehicle body to load, transport, and unload luggage, in which the loading platform is moved by the robot arm so that the area of the loading platform as viewed from above is larger when loading and unloading than when the platform is empty.

According to the automated guided vehicle of the present invention, the area of the loading platform as viewed from above is reduced when the vehicle is empty compared to when it is loaded or unloaded, making it easier to turn around in narrow spaces, and the automated guided vehicle can pass through narrow, bent passages from the waiting point to the loading point, and from the unloading point to the waiting point or loading point, increasing the freedom of the layout of the passages. On the other hand, the area of the loading platform as viewed from above is increased when the loading and unloading are performed compared to when it is reduced, allowing the amount of luggage that can be loaded to be increased.

In particular, in the present invention, the platform moves so that the area of the platform when viewed from above is reduced even during transport of luggage when loading and unloading, making it unnecessary to adjust the width of the aisle from the loading point to the unloading point to accommodate an automated guided vehicle fully loaded with luggage.

In addition, with the automated guided vehicle of the present invention, the expansion or reduction of the area of the platform as viewed from above is achieved by the robot arm moving the platform, eliminating the need for a drive source to move the platform, which in turn simplifies the structure of the automated guided vehicle and makes it possible to make it smaller.

FIG. 1A is a front view of an automated guided vehicle 1A according to an embodiment of the present invention with the area of the platform reduced when viewed from above. FIG. 1B is a side view of the automated guided vehicle 1A of the embodiment in a state where the area of the platform is reduced when viewed from above. FIG. 1C is a top view of the automated guided vehicle 1A of the embodiment in a state where the area of the platform as viewed from above is reduced. FIG. 2A is a front view of an automated guided vehicle 1A according to the embodiment, showing an enlarged top view of the platform. FIG. 2B is a side view of the automated guided vehicle 1A of the embodiment with the area of the platform enlarged when viewed from above. FIG. 2C is a top view of the automated guided vehicle 1A of the embodiment with the area of the platform enlarged as viewed from above. FIG. 3A shows a front view, a right side view, a left side view, and a rear view of the end effector. FIG. 3B is a side view of the end effector with the opening/closing member in an open state. FIG. 4 is an explanatory diagram of a luggage transport path. FIG. 5A is an explanatory diagram of a loading method using the automated guided vehicle 1A of the embodiment. FIG. 5B is an explanatory diagram of a loading method using the automated guided vehicle 1A of the embodiment. FIG. 5C is an explanatory diagram of a loading method using the automatic guided vehicle 1A of the embodiment. FIG. 5D is an explanatory diagram of a loading method using the automated guided vehicle 1A of the embodiment. FIG. 5E is an explanatory diagram of a loading method using the automated guided vehicle 1A of the embodiment. FIG. 5F is an explanatory diagram of a loading method using the automated guided vehicle 1A of the embodiment. FIG. 6 is a front view and a side view of the automated guided vehicle 1A of the embodiment after loading and before transportation. FIG. 7 is a front view and a side view of the automated guided vehicle 1A of the embodiment when transporting luggage. FIG. 8A is an explanatory diagram of a method for unloading a load using the automated guided vehicle 1A of the embodiment. FIG. 8B is an explanatory diagram of a method for unloading a load using the automated guided vehicle 1A of the embodiment. FIG. 8C is an explanatory diagram of a method for unloading a load using the automated guided vehicle 1A of the embodiment. FIG. 8D is an explanatory diagram of a method for unloading a load using the automated guided vehicle 1A of the embodiment. FIG. 9A is a front view of an automated guided vehicle 1B according to the embodiment with the area of the platform reduced when viewed from above. FIG. 9B is a side view of the automated guided vehicle 1B of the embodiment in a state where the area of the platform in a top view is reduced. FIG. 9C is a top view of the automated guided vehicle 1B of the embodiment in a state where the area of the platform as viewed from above is reduced. FIG. 10A is a side view of an automated guided vehicle 1B according to the embodiment with the area of the platform enlarged when viewed from above. FIG. 10B is a top view of the automated guided vehicle 1B of the embodiment with the area of the platform enlarged as viewed from above. FIG. 11 is an explanatory diagram of a luggage transport path. FIG. 12A is an explanatory diagram of a loading method using the automated guided vehicle 1B of the embodiment. FIG. 12B is an explanatory diagram of a loading method using the automated guided vehicle 1B of the embodiment. FIG. 12C is an explanatory diagram of a loading method using the automated guided vehicle 1B of the embodiment. FIG. 12D is an explanatory diagram of a loading method using the automated guided vehicle 1B of the embodiment. FIG. 12E is an explanatory diagram of a loading method using the automated guided vehicle 1B of the embodiment. FIG. 12F is an explanatory diagram of a loading method using the automated guided vehicle 1B of the embodiment. FIG. 13A is a top view of an automated guided vehicle 1C according to an embodiment in a state in which the area of the platform as viewed from above is reduced. FIG. 13B is a side view of the automated guided vehicle 1C of the embodiment in a state where the area of the platform in a top view is reduced. FIG. 14 is a top view of an automated guided vehicle 1C according to the embodiment, with the area of the platform as viewed from above enlarged.

The present invention will now be described in detail with reference to the drawings. Note that the same reference numerals in each drawing represent the same or equivalent components.

<Overall configuration of the automated guided vehicle>
Fig. 1A is a front view of an automated guided vehicle 1A according to an embodiment of the present invention with the area of the platform reduced when viewed from above, Fig. 1B is a side view thereof, Fig. 2A is a front view of the automated guided vehicle 1A with the area of the platform enlarged when viewed from above, Fig. 2B is a side view thereof.

This automated guided vehicle 1A uses an automatic transfer method to automatically transport luggage, and is equipped with a dual-arm robot 10 equipped with two vertical articulated robot arms 11 at the front of the vehicle body 2 in the direction of travel, with a loading platform 40 mounted further in front of that. The vehicle body 2 is also equipped with an automatic driving system that enables the automated guided vehicle 1A to automatically travel through designated paths to loading points, unloading points, waiting points, etc.

The method of the automatic driving system is not particularly limited, and examples thereof include route guidance, autonomous movement, and following. Among these, examples of route guidance include electromagnetic induction, optical induction, magnetic induction, and magnetic material induction, and an appropriate method is selected based on the constraints of the available sensors and floor. In addition, the method of estimating the self-position and the method of improving the accuracy in the autonomous moving system are not particularly limited, and examples thereof include laser ranging, laser SLAM (Simultaneous Localization And Mapping), and image SLAM. In addition, it is common to use LRF (Laser Range Finder), also known as Lidar (Light Detection and Ranging), to detect the position distribution of surrounding objects. As an example of improving the accuracy of automatic driving, fixed point correction using RFID, QR Code (registered trademark), magnets, etc. may be performed.

(Cargo bed)
The loading platform can take various shapes depending on the type of cargo to be transported, but in this embodiment, the cargo is a plate-shaped material such as a blank sheet of cardboard, and a loading platform 40 having an L-shaped cross section is provided. That is, the loading platform 40 is formed of a wide surface portion 42 forming the long side of the L shape and a narrow surface portion 43 forming the short side. In the narrow surface portion 43, the loading platform is rotatably attached to the vehicle body 2 at or near the end side opposite the wide surface portion 42, and a horizontally extending rotation shaft 41 is provided at the mounting portion. Therefore, the loading platform 40 can rotate around the rotation shaft 41 (FIGS. 1B and 2B).
The loading platform 40 may be attached to the vehicle body 2 in such a manner that the side between the wide surface portion 42 and the narrow surface portion 43 serves as a rotation axis 41 and the rotation axis 41 is attached to the vehicle body 2 so as to be rotatable.

In the present invention, the type of luggage is not limited. For example, the shape can be box-like, plate-like, roll-like, bottle-like, etc., and the material can be paper, wood, metal, resin, etc. Also, the outer shape of the loading platform can be basket-like, box-like, tray-like, etc., depending on the shape of the luggage. The loading platform may be provided with ridges, grooves, etc., to prevent the luggage from rattling.

When the unmanned guided vehicle 1A moves empty, the platform 40 can be rotated to a position where the surface formed by the narrow surface portion 43 is substantially horizontal and the surface formed by the wide surface portion 42 is upright (FIG. 1B). At this time, the area of the platform 40 as viewed from above is the diagonally hatched area S0 in FIG. 1C, and the total length of the unmanned guided vehicle 1A is L0.

In the automated guided vehicle 1A, the platform 40 can be rotated to this position when transporting luggage, so that the area of the platform 40 as viewed from above becomes S0. In this case, the surface formed by the narrow surface portion 43 can function as a platform for placing luggage, and the surface formed by the wide surface portion 42 can function as a back panel.

On the other hand, when loading or unloading, the platform 40 can be rotated to make the surface formed by the wide surface portion 42 horizontal, allowing that surface to function as a platform for placing luggage, and the surface formed by the narrow surface portion 43 to function as a back panel (Fig. 2B). At this time, the area of the platform 40 as viewed from above is the diagonally hatched area S1 in Fig. 2C, which is larger than the area S0 when unloaded or during transport described above. In addition, the total length of the automated guided vehicle 1A is L1, which is longer than the total length L0 when unloaded or during transport described above.

By rotating the platform 40 around the pivot shaft 41 in this way, the area of the platform 40 as viewed from above can be enlarged when loading and unloading compared to when it is empty, but when transporting luggage after loading, the platform 40 can be rotated to the same position as when it is empty to reduce the area of the platform 40 as viewed from above and shorten the overall length of the automated guided vehicle 1A. Therefore, if there is a bent section in the passage through which the automated guided vehicle passes, the passage width does not need to be a wide passageway that can accommodate an automated guided vehicle with a total length of L1, but a narrow passageway that can accommodate an automated guided vehicle with a total length of L0 will suffice.

As described above, the rotation of the platform 40, which enlarges or reduces the area of the platform 40 when viewed from above, is performed by the robot arm 11. That is, the rotation is performed by the robot arm 11 acting on the platform 40 or releasing that action. Here, the robot arm 11 acting on the platform 40 means that the robot arm 11 pushes up, supports, clamps, or the like the platform 40 with the end effector 20. Therefore, this automated guided vehicle 1A is not equipped with a drive source for rotating the platform 40, and as a result, the configuration of the automated guided vehicle 1A is compact.

As shown in FIG. 1B, it is preferable that the angle θ of the wide surface portion 42 with the horizontal when the wide surface portion 42 is raised is less than 90°. This allows the loading platform 40 to be rotated by gravity to a position (FIG. 2B) where the wide surface portion 42 is approximately horizontal, simply by releasing the support of the robot arm 11 on the loading platform 40. In this case, a damper or spring material may be incorporated into the rotating shaft 41 to prevent the loading platform 40 from being suddenly rotated from the raised position shown in FIG. 1B to the horizontal position shown in FIG. 2B, which would cause an impact on the loading platform 40. In this case, an elastic force is applied by the damper or spring material in the direction in which the wide surface portion 42 is raised, but the robot arm 11 applies a force against the elastic force, for example, downward from above the wide surface portion 42, to maintain the wide surface portion 42 horizontal.

(Robot arm)
In this embodiment, as the robot arms 11, vertical multi-joint type robot arms are provided as the left and right arms of the dual-arm robot 10. In the present invention, the robot arm is not limited to this and may be a horizontal multi-joint type, a parallel link type, or the like, but by using a vertical multi-joint type, the motion range of the arm can be maximized.

When mounting the robot arm on an automated guided vehicle, in the automated guided vehicle 1A of this embodiment, as shown in Figures 1A and 2A, the left and right robot arms 11 are attached to bases 12, and the bases 12 are attached to the vehicle body 2, but the robot arms 11 may be attached directly to the vehicle body 2 as in the automated guided vehicle 1B of an embodiment described later (Figures 10A and 10B).
When the robot arm 11 is attached to the base 12, it is preferable that the base 12 be rotatable in a horizontal plane on the vehicle body 2. This allows the loading and unloading of cargo to be performed in front of the robot regardless of the orientation of the vehicle body 2 of the automated guided vehicle 1A, optimizing the transfer operation and widening the operating range of the robot arm 11, which is preferable.

The left and right robot arms 11 are mutually monitored by a control device, and it is preferable that the arms are controlled so that their respective parts, such as the arm tips, do not interfere with each other. This makes it possible to prevent the left and right robot arms 11 from coming into contact with each other and being damaged when interference occurs due to an error in the operation program of the robot arms 11, or when each robot arm 11 performs an autonomous operation based on the recognition of an image taken by a camera equipped in the robot 10.

In addition, in the present invention, the robot arm is not limited to a dual-arm type. Three or more robot arms may be provided on the automated guided vehicle 1A, which enables a wide variety of tasks.

(End effector)
End effectors 20 are provided at the tips of the left and right robot arms 11 .
In order for the end effector 20 to directly act on the platform 40 to rotate the platform 40 to a predetermined position and to facilitate operations such as loading and unloading, the end effector 20 may be provided with a rod-shaped, plate-shaped, or other protruding portion that engages with the platform 40. For example, depending on the material, shape, and other factors of the cargo handled by the automated guided vehicle 1A, the end effector 20 may be provided with a gripping portion that can grip the cargo or a suction portion that can adhere to the cargo. In addition, a blade that can cut a string binding the cargo may be provided.

The end effector 20 shown in Figure 3A is an example of an end effector provided on the robot arm 11 of the dual-arm robot shown in Figure 1A. This end effector 20 has a pair of opening and closing members 22 with one end opening and closing at the tip of the extension 21, and a plate-shaped pushing member 23 protrudes from the opposite end of the opening and closing. The end effector 20 also has a flat rod-shaped holding member 24 that protrudes in a direction perpendicular to the protruding direction of the pushing member 23.

The pair of opening/closing members 22 are beak-shaped with the thickness of the opening/closing ends tapering toward the tips. A cutting blade 25 is provided inside the opening/closing members 22, which are the parts that face each other when the opening/closing members 22 are closed, and the cutting blade 25 is exposed when the opening/closing members 22 are opened as shown in FIG. 3B. Therefore, when the cargo to be loaded onto the automated guided vehicle 1A is a stack of plate-like materials such as blank sheets for cardboard boxes bound together with string, the opening/closing members 22 have a shape suitable for inserting the thinner end of the opening/closing members 22 between the plate-like materials and the string, pulling up the string, cutting the string with the cutting blade 25, and pinching and removing the cut pieces with the opening/closing members 22.

The retaining member 24 is useful when the cargo to be loaded is bundled together from stacked sheet material as described above, by inserting it between the stacked sheet material bundled together to lift the bundle or to engage with a protrusion on the loading platform.
The pushing member 23 is useful for pushing unloaded cargo into a designated location at the unloading point.

(Image Recognition)
In the automated guided vehicle 1A of this embodiment, a camera 30 used for image recognition is provided above the base 12 of the dual-arm robot 10, that is, at a position equivalent to the head 13 if the dual-arm robot 10 were considered to be humanoid, and an image recognition system is built into the robot 10. Image information captured by the camera 30 is sent to the robot 10 by wire or wirelessly, making it possible to perform advanced operation control of the robot arm 11.

In other words, an automated guided vehicle, whether its automatic driving method is a route guidance type, an autonomous moving type, or a follow-up type, generally cannot stop precisely at the target stopping position. A position error of about ±50 mm usually occurs. Even when an automated guided vehicle further uses correction sensors such as an image sensor, a floor mark detection sensor, or a distance sensor, a position error of about ±10 mm occurs. For this reason, when loading or unloading cargo, when high precision is required for the positional relationship between the robot arm and its surroundings, it causes problems in transferring cargo.

In contrast, even without a correction sensor, an image recognition system can recognize images of markers and distinctive objects around work points such as loading and unloading, and when the AGV reaches the target stopping position, that information is sent to the automatic driving system. Alternatively, the image recognition system estimates the amount of deviation or angle of the actual stopping position of the AGV relative to the target stopping position, and corrects the operation of the robot arm. This ensures that the intended operation can be performed. Without a correction sensor, position errors that the image recognition system cannot recognize may occur, so it is preferable to use a correction sensor in combination.

In addition to using an image recognition system to correct the stopping position of the automated guided vehicle 1A, the operation of the robot arm 11, such as loading and unloading, may be performed by using the image recognition system to recognize objects such as luggage and loading platforms. Furthermore, the image recognition system may be used to inspect the barcodes and color of luggage. The image recognition system may also be used to improve safety during travel. Meanwhile, a dedicated barcode reader may be used to inspect the barcodes of luggage.

There are no particular limitations on the camera 30 used for image recognition or the image recognition system itself. Any known image recognition system that processes information on two-dimensional images or three-dimensional images obtained using a stereo camera or the like can be used. In addition, a system that uses augmented reality (AR) to obtain information on the size, orientation, and degree of deformation of a marker from a captured image and uses this to estimate the amount of deviation in the position of the robot arm may be used. Appropriate selection is made depending on the object to be recognized, processing time, cost, etc.

The installation position of the camera is not particularly limited. For example, as in the automated guided vehicle 1B (FIGS. 10A and 10B) of the embodiment described later, a tall pole-shaped installation tool 31 may be erected on the automated guided vehicle separately from the base 12 of the robot arm 11, and the camera 30 may be installed on the installation tool 31. By setting the installation position of the camera 30 high, the baggage can be confirmed from a distance. Therefore, the distortion of the image caused by the camera lens can be reduced, and the misidentification of the baggage position can be prevented. In addition, especially when moving, the high position of the camera 30 makes it possible to monitor the forward direction in the direction of travel without being obstructed by the loaded baggage or the loading platform. On the other hand, when an image recognition system is used for the operation of the robot arm such as loading and unloading, the camera may be installed at the tip of the robot arm. In this case, the camera can approach the baggage, making it easier to inspect the baggage.

(Example of luggage transportation)
As an example of a method for transporting luggage using the unmanned guided vehicle 1A, a method in which a blank sheet of cardboard is used as luggage B and the unmanned guided vehicle 1A passes through the passage shown in Figure 4 to load and unload the luggage will be described with reference to Figures 5A to 5F, Figures 6, 7, and Figures 8A to 8D.

The passage shown in FIG. 4 has a waiting point P1, a loading point P2, and an unloading point P3 for the automated guided vehicle 1A. It has a first corner between the waiting point P1 and the loading point P2, and a second corner between the loading point P2 and the unloading point P3. It is also possible to provide an additional passage that returns from the unloading point P3 to the waiting point P1, making it a circular type passage. In this case, the unloading point P3 is the third corner, and a fourth corner can be provided between the unloading point P3 and the waiting point P1.

At waiting point P1, as shown in Figures 1A and 1B, the holding member 24 of the end effector 20 supports the outer surface 42a of the wide surface portion 42 of the platform 40, and the wide surface portion 42 is raised at an angle θ, thereby reducing the area of the platform 40 as viewed from above. At this time, the area of the platform 40 of the automated guided vehicle 1A as viewed from above is S0 (Figure 1C), and the total length of the automated guided vehicle 1A is L0. In addition, the vehicle body 2 of the automated guided vehicle 1A faces forward to check for surrounding installations and markers. After this check, the automated guided vehicle 1A turns the first corner and heads toward the loading point P2.

At the baggage storage area C at the side of the aisle at loading point P2, a stack of blank cardboard sheets B1 bound together with string Bx is placed. The automated guided vehicle 1A automatically stops alongside the baggage storage area C with its side facing the baggage storage area C (Figure 5A).

In the present invention, the shape of the luggage storage area C is appropriately selected depending on the luggage to be transported. The platform on which the luggage is placed can be a horizontal surface or an inclined surface with a stopper. The platform may be in the form of a shelf. The platform may also be movable horizontally or vertically, or rotate.

At the loading point P2, the holding member 24 of the end effector 20 slowly moves downward with the movement of the robot arm 11. As a result, the loading platform 40 rotates under its own weight around the pivot shaft 41 located at the front of the vehicle body 2, and the area of the loading platform 40 in a top view expands to S1, as shown in Figures 2A and 2B.

Next, as shown in FIG. 5A, the base 12 of the robot 10 is rotated horizontally so that the front of the robot 10 faces the luggage storage location C, and both the left and right robot arms 11 can act on the luggage, and the head 13 faces slightly downward so that the camera 30 can capture the luggage. By pulling up the unmanned guided vehicle 1A next to the luggage storage location C and facing the front of the robot 10 toward the luggage storage location C in this way, the left and right robot arms 11 approach the luggage at the luggage storage location C, so that the arm length of the robot arm 11 required for lifting the luggage can be shortened. This makes it possible to select a compact robot arm 11 to be mounted on the unmanned guided vehicle 1A. Therefore, the cost required for the robot arm 11 can be reduced. In addition, since the weight of the robot arm 11 can be reduced, the center of gravity of the unmanned guided vehicle 1A can be prevented from becoming high, and the risk of tipping over can be reduced. Furthermore, the unmanned guided vehicle 1A can be made small and inexpensive. The effect of reducing the load on the robot arm 11 by shortening the length of the robot arm 11 is particularly noticeable when the load to be lifted is not individual blank sheets but a bundle B1 of blank sheets, which is therefore heavy.
Furthermore, by tilting the head 13 slightly downward as shown in FIG. 5A, the baggage B in the baggage storage area C comes into the sufficient field of view of the camera 30.
The front of a robot refers to the side on which the arms are located. If there are two such sides, a front and a back, and the movement of the arms is limited to one of them, only the side on which the arms can move is called the front.

Next, the sheet stack B1 is inserted into the holding member 24 of the end effector 20, the sheet stack B1 is clamped between the left and right end effectors 20, and the sheet stack B1 is lifted upward. After lifting, the weight of the sheet stack B1 is measured using a measuring device (not shown) provided on the robot arm 11, and the number of blank sheets forming the sheet stack B1 can be estimated from the known weight of one blank sheet. Also, after the sheet stack B1 is inserted into the holding member 24, the number of sheets may be measured using a camera (not shown) provided on the robot arm 11.

After the left and right end effectors 20 lift the sheet stack B1, the base 12 of the robot 10 rotates horizontally, and the front of the robot 10 faces the loading platform 40 (FIG. 5B). Next, the end effectors 20 are lowered, the holding members 24 are pulled out from the sheet stack B1, and the sheet stack B1 is placed on the loading surface formed by the wide surface portion 42 of the loading platform 40 (FIG. 5C). By facing the front of the robot 10 toward the loading platform 40 when placing the sheet stack B1 on the loading platform 40 in this way, the length of the robot arm 11 can be shortened, and the load on the robot arm 11 when placing the sheet stack B1 can be reduced, just as when lifting the sheet stack B1.

With the sheet stack B1 placed on the loading platform 40, the tip of the opening/closing member 22 of the end effector 20, which is thinner, is inserted between the blank sheet B and the string Bx, the string Bx is pulled up, and the string Bx is cut by the cutting blade 25. The cut end of the string Bx is then clamped by the opening/closing member 22 and removed from the stack of blank sheets B. By removing the string Bx during loading in this way, when the blank sheet B is supplied to the box making machine D at the unloading point P3, the box making machine D can smoothly enter the box making process.

Next, in order to load the second sheet stack B1 onto the loading platform 40, the base 12 of the robot 10 rotates horizontally again, facing the baggage storage area C, the holding member 24 of the end effector 20 is inserted into the second sheet stack B1, and the sheet stack B1 is clamped between the left and right end effectors 20 (Fig. 5D). The sheet stack B1 is then lifted upward. After that, the base of the robot 10 rotates horizontally so that the front of the robot 10 is positioned directly behind the loading platform 40 (Fig. 5E), and in the same manner as described above, another sheet stack B1 is placed on top of the blank sheets B previously placed on the loading platform 40 (Fig. 5F). The string Bx of this sheet stack B1 is also removed in the same manner as described above. When loading is completed, the area of the loading platform 40 as viewed from above expands to S1 as shown in Fig. 2C, and the overall length of the automated guided vehicle 1A also increases to L1.

Next, in order to rotate the loaded platform 40 around the pivot shaft 41 to reduce the area of the platform 40 as viewed from above, first, the holding members 24 of the end effectors 20 of the left and right robot arms 11 are placed against the underside of the wide surface portion 42 of the platform 40 (FIG. 6). Next, the end effectors 20 are lifted to rotate the platform 40 around the pivot shaft 41, and the wide surface portion 42 is raised at an angle θ (FIG. 1B) (FIG. 7). As a result, the area of the platform 40 as viewed from above is reduced to S0 as shown in FIG. 1C, and the total length of the automated guided vehicle 1A becomes L0. In addition, the camera 30 faces forward in a direction suitable for movement. Then, the automated guided vehicle 1A starts moving toward the unloading point P3.

When moving, the area of the platform 40 in a top view of the automated guided vehicle 1A is reduced to S0, and the overall length of the automated guided vehicle 1A is also shortened to L0, so that the automated guided vehicle 1A can pass through a narrow, curved passageway, such as the passageway from the waiting point P1 to the loading point P2, without colliding with surrounding structures. In contrast, if the platform 40 is not rotated after loading, and the area of the platform 40 in a top view is expanded to area S1, and the length of the automated guided vehicle 1A remains L1, the automated guided vehicle 1A will not be able to turn the second corner between the loading point P2 and the unloading point P3, and it will be necessary to widen the passageway width as shown by the dashed line in Figure 4 in order to enable the automated guided vehicle 1A to turn the second corner.

At the unloading point P3, the unmanned transport vehicle 1A is positioned in front of the receiving table E for supplying blank cardboard sheets to the box-making machine D, and the transported blank cardboard sheets B are placed on the receiving table E. Therefore, the unmanned transport vehicle 1A first stops precisely at the unloading point P3 (Figure 8A).

Next, the holding member 24 of the end effector 20, which had been supporting the wide surface portion 42 of the platform 40, slowly descends due to the movement of the robot arm 11, the platform 40 rotates about the pivot shaft 41, the wide surface portion 42 of the platform 40 becomes horizontal, and the area of the platform 40 as viewed from above expands to S1 as shown in Fig. 2C (Fig. 8B). Even during this rotation, the movement of the robot arm 11 is appropriately controlled, and the rotation is gradually accelerated, thereafter a constant rotation speed is maintained, and finally the blank sheets stacked on the platform 40 are stably held.
In addition, it is preferable that the thickness and vertical position of the loading platform 40 be adjusted in advance so that after rotation, the loading surface for the blank sheets B on the wide surface portion 42 of the loading platform 40 is slightly higher than the loading surface of the receiving platform E.

Next, the pushing member 23 of the end effector 20 is inserted between the stacked blank sheets B and the surface of the narrow surface portion 43 of the loading platform 40 that serves as the backrest for the stacked blank sheets B (Fig. 8C), and the pushing member 23 pushes the stacked blank sheets B toward the receiving platform E of the box former D (Fig. 8D). At this time, if the loading surface of the loading platform 40 for the blank sheets B is slightly higher than the loading surface of the receiving platform E, the stacked blank sheets B will not get caught on the receiving platform E, and the stacked blank sheets B can be pushed out smoothly.

When the unloading operation is completed, in order for the automated guided vehicle 1A to return to the initial waiting point P1, first the holding member 24 of the end effector 20 is placed against the underside of the wide surface portion 42 of the platform 40, and the end effector 20 is lifted by moving the robot arm 11, thereby rotating the platform 40 around the rotation axis 41, raising the wide surface portion 42 at an angle θ, reducing the area of the platform 40 as viewed from above to S0 as shown in Figure 1C, and the overall length of the automated guided vehicle 1A is set to L0.
The automated guided vehicle 1A can turn around at the unloading point P3 and return along the same path A from the unloading point P3 to the waiting point P1 as shown by the dashed line in FIG.

<Modification 1 of the unmanned transport vehicle>
(Cargo bed)
The automated guided vehicle of the present invention can take various forms. For example, a plurality of horizontally movable platforms may be stacked one on top of the other so that the area of the platform as viewed from above is enlarged when loading and unloading compared to when the platform is empty.

Figure 9A is a front view of one embodiment of an automated guided vehicle in which two horizontally movable loading platforms 50a, 50b are arranged to be stacked one on top of the other, and Figure 9B is a side view of the same. In the illustrated state, the two loading platforms 50a, 50b are stacked one on top of the other, and the total area of the loading platforms 50 combined as viewed from above is the diagonally hatched area S0 in Figure 9C, and the total length of the automated guided vehicle 1B is L0.

The upper loading platform 50a is mounted on a slider 51 and can move horizontally in the fore-and-aft direction of the vehicle body 2 as shown by the arrow. In order to facilitate horizontal movement of the upper loading platform 50a by the action of the end effector 20, a U-shaped protrusion 53 that engages with the holding member of the end effector is provided on the side of the upper loading platform 50a. Therefore, by engaging the holding member of the end effector 20 with this U-shaped protrusion 53 and pushing the upper loading platform 50a horizontally with the end effector 20, the upper loading platform 50a can easily move horizontally.

When the upper platform 50a of the vertically overlapping platforms 50a, 50b is slid forward, the vertical overlap between the two platforms 50a, 50b can be eliminated, as shown in FIG. 10A. At this time, the area of the platforms 50a, 50b when viewed from above becomes the area S1 hatched diagonally in FIG. 10B, and the total length of the automated guided vehicle 1B becomes L1. This area S1 is larger than the above-mentioned area S0, and the total length L1 is also longer than the above-mentioned total length L0. With the automated guided vehicle 1B, loading and unloading of cargo can be performed with the areas of the platforms 50a, 50b when viewed from above expanded in this way.

This automated guided vehicle 1B transports bottles B2 as cargo. Therefore, each loading platform 50a, 50b is box-shaped with left, right, front and back walls so that it can hold bottles, and is deep enough to hold bottles B2.

In addition, in this automated guided vehicle 1B, in order to ensure image recognition by minimizing the difference in distance from the camera 30 to the bottles B2 on each loading platform 50a, 50b, the vertical distance between the two loading platforms 50a, 50b is narrower than the height of the bottles B2 to be loaded, and the distance is very small (FIG. 12F). Therefore, after the bottles B2 are loaded, the two loading platforms 50a, 50b cannot be stacked one on top of the other as when they are empty. Therefore, after loading bottles at the loading point, during the movement to the unloading point, unlike the previously described automated guided vehicle 1A, the area of the loading platform in a top view cannot be made as small as when it is empty, and the overall length of the automated guided vehicle cannot be shortened.

On the other hand, if the upper loading platform 50a is slid forward and the two loading platforms 50a, 50b are no longer overlapping vertically, and the position of the upper loading platform 50a is set so that it protrudes slightly forward from the vehicle body 2 when viewed from above, it will be able to enter a narrow passageway that is wide enough for the empty vehicle to pass through when transporting bottles, and turn corners.

Therefore, if there is no problem in recognizing the position of the bottles B2 on the two loading platforms 50a, 50b, the vertical distance between the two loading platforms 50a, 50b may be made wider than the height of the bottles B2 to be loaded, so that after the bottles B2 are loaded, the two loading platforms 50a, 50b can be stacked one on top of the other as if they were empty. In this case, after the bottles are loaded at the loading point, the area of the loading platforms can be made narrower as when they are empty, even while moving to the unloading point, and the overall length of the automated guided vehicle can be shortened.

In the automated guided vehicle 1B of this embodiment, the lower platform 50b is divided by a dividing line that extends in the sliding direction of the upper platform 50a, and the legs 52 that connect the upper platform 50a and the slider 51 are formed thin enough to pass through this dividing line (Figure 9A).

In an automated guided vehicle equipped with a slider 51 like this, the type of slider is not particularly limited. For example, a combination of slippery plates, a combination of a roller conveyor and a plate, a slide rail, a slide guide, etc. are possible. In particular, a slide guide with a ball bearing built into the slide block is the most preferable because it is highly rigid and compact.

In addition, to prevent the upper platform 50a from sliding due to vibrations or the like when the robot arm 11 is performing work, it is desirable to provide a mechanism for temporarily fixing the position of the upper platform 50a. Examples of such mechanisms include a combination of a retractable spring ball plunger and a recess, an electromagnet, or a combination of a convex part and a concave part using an air cylinder or an electric cylinder.

(Robot arm)
The automated guided vehicle 1B of this embodiment is used to load bottles one by one onto the loading platform 50 at a loading point and to unload the bottles one by one into predetermined positions at an unloading point, so a single vertical articulated robot arm 11 is attached to the vehicle body 2 as a robot arm.

The end effector 20 at the tip of the robot arm 11 is provided with a clamping member 26 suitable for picking up and down the bottles B2. The end effector 20 may also perform tasks such as aligning the bottles B2 while transporting the cargo.

In the present invention, the work performed by the end effector is not particularly limited, and various work can be performed depending on the type and condition of the luggage being transported by the automated guided vehicle. Examples include assembly, screwing, welding, painting, etc. By performing work while transporting luggage, the automated guided vehicle can be operated efficiently.

(camera)
In the automated guided vehicle 1B of this embodiment, the camera 30 used for image recognition is attached to a tall pole-like installation tool 31 standing up from the vehicle body 2, and is installed at a high position above the two loading platforms 50a, 50b. This makes it possible to reduce image distortion caused by the camera lens, and to prevent misidentification of the position of the bottle B2.

(Example of luggage transportation)
As an example of a method for transporting luggage using the unmanned guided vehicle 1B, a method in which the unmanned guided vehicle 1B passes through the passage shown in Figure 11 and loads and unloads bottles B2 will be described with reference to Figures 12A to 12F.

The passage shown in FIG. 11 is of a circular type, and has a waiting point P1, a loading point P2, and an unloading point P3 for the automated guided vehicle 1B. A first corner is between the waiting point P1 and the loading point P2, a second corner is between the loading point P2 and the unloading point P3, and a third corner and a fourth corner are between the unloading point P3 and the waiting point P1. The passage width from the second corner to the third corner is wider than the passage width in other parts.

At the waiting point P1, the two loading platforms 50a, 50b of the automated guided vehicle 1B are stacked vertically as shown in Figures 9A to 9C, and the area of the loading platform 50 as viewed from above is reduced to S0. The automated guided vehicle 1B turns the first corner from the waiting point P1 and heads toward the loading point P2.

When the automated guided vehicle 1B stops at the loading point P2, loading begins with the two loading platforms 50a, 50b stacked one on top of the other. Loading begins with the clamping member 26 of the end effector 20 at the tip of the robot arm 11 picking up bottles B2 one by one from the luggage storage area C (Figure 11) and loading them onto the upper loading platform 50a (Figure 12A).

The loading of bottles B2 onto the upper platform 50a is repeated (FIG. 12B), and when this is completed, the end effector 20 at the tip of the robot arm 11 moves to a position on the upper platform 50a closer to the base of the robot arm 11 (FIG. 12C). Then, the holding member 24 (FIG. 9A) that protrudes in a different direction from the clamping member 26 on the end effector 20 engages with the U-shaped protrusion 53 (FIG. 9B) attached to the upper platform 50a (FIG. 12C), and the movement of the robot arm 11 horizontally moves the upper platform 50a away from the base of the robot arm 11 (FIG. 12D). This causes the area of the platform 50 in a top view to expand to S1 (FIG. 10B).

Next, the end effector 20 again picks up the bottle B2 from the baggage storage area C (FIG. 11) and loads it onto the lower loading platform 50b (FIG. 12E). The loading of the bottle B2 onto the lower loading platform 50b is repeated, and when this is completed (FIG. 12F), the automated guided vehicle 1B moves to the unloading point P3.

At the unloading point P3, the bottles B2 loaded on the lower loading platform 50b are unloaded by the robot arm 11 to a predetermined bottle storage area F (FIG. 11). When the unloading of the lower loading platform 50b is completed, the holding member 24 (FIG. 9A) of the end effector 20 engages with the U-shaped protrusion 53 of the upper loading platform 50a, and the upper loading platform 50a moves horizontally toward the base side of the robot arm 11 due to the movement of the robot arm 11 and overlaps with the lower loading platform 50b vertically, and the total area of the loading platform as viewed from above is reduced to S0 (FIG. 9C). In this state, the bottles loaded on the upper loading platform 50a are unloaded to the bottle storage area F. When the loading and unloading of the bottles on the upper loading platform 50a is also completed, the automated guided vehicle 1B moves to the waiting point P1. Alternatively, it moves to the loading point P2 and repeats the above-mentioned loading and unloading operations.

<Modification 2 of the unmanned transport vehicle>
In the present invention, in order to increase the area of the loading platform in a top view when loading and unloading compared to when the platform is empty, multiple loading platforms held one above the other may be rotated and moved horizontally.
Such an embodiment is useful when the automated guided vehicle follows different paths when it is loaded and when it is unloaded, and the paths are narrow when it is unloaded.

For example, the automated guided vehicle 1C shown in Figures 13A and 13B has three fan-shaped platforms 60a, 60b, and 60c as its platform 60, of which the top platform 60a is fixed, while the middle platform 60b and the bottom platform 60c are rotatable around a rotation shaft 61. A rotation synchronization mechanism 62 consisting of gears and the like is attached to the middle platform 60b and the bottom platform 60c, and when one of these platforms is opened by the rotation of a drive motor (not shown), the other also opens in the opposite direction by the same angle due to the meshing of the gears.

When the area of the loading platform 60 in a top view is reduced, the middle loading platform 60b and the lower loading platform 60c are hidden under the upper loading platform 60a as shown in Figures 13A and 13B.

On the other hand, when the area of the platform 60 in a top view is to be enlarged, for example, the holding member 24 of the end effector 20 is engaged with the lower platform 60c and pulled to open the fan shape. This causes the middle platform 60b to open as well. Therefore, as shown in FIG. 14, the fan shape is opened to enlarge the area of the platform 60 in a top view.
In addition, the present invention can take various other forms.

Reference Signs List 1A, 1B, 1C Automatic guided vehicle 2 Vehicle body 10 Robot 11 Robot arm 12 Base 13 Head 20 End effector 21 Extension 22 Opening/closing member 23 Pushing member 24 Holding member 25 Cutting blade 26 Clamping member 30 Camera 31 Installation tool 40 Loading platform 41 Rotating shaft 42 Wide surface portion 42a Outer surface 43 of wide surface portion Narrow surface portion 50a, 50b Loading platform 51 Slider 52 Leg 53 U-shaped protrusions 60a, 60b, 60c Loading platform 61 Rotating shaft 62 Rotation synchronization mechanism A Passage B Baggage, blank sheet B1 Sheet stack B2 Bottle Bx String C Baggage storage location D Box former E Receiving platform F Bottle placement area L0, L1 Total length P1 of loading platform as viewed from above Waiting point P2 Loading point P3 Unloading point S0, S1 Area of the loading platform as viewed from above θ Angle between the wide part and the horizontal

Claims (8)

An automated guided vehicle having a robot arm and a carrier mounted on a vehicle body,
The platform has a horizontal rotation axis, and the wide surface portion and the narrow surface portion are arranged in an L-shape in a cross section perpendicular to the rotation axis.
The robot arm rotates the platform,
When transporting luggage, the area of the wide surface portion as viewed from above can be reduced compared to when loading or unloading the luggage, and the wide surface portion can function as a back panel for the luggage.
The unmanned transport vehicle can enlarge the area of the wide surface portion in a top view when loading or unloading the cargo compared to when the cargo is being transported, and can cause the wide surface portion to function as a platform on which the cargo is stacked . 2. The automated guided vehicle according to claim 1, wherein a driving source for enlarging or reducing the area of the wide surface portion of the platform as viewed from above is not mounted on the vehicle body other than the robot arm . An automated guided vehicle according to claim 1 or 2, in which the robot arm acts directly on the platform to rotate the platform, thereby reducing the area of the wide surface area as viewed from above, and when this action is released, the platform rotates due to gravity, thereby expanding the area of the wide surface area as viewed from above. An automated guided vehicle according to claim 1 or 2, in which multiple horizontally movable platforms are arranged so as to be stacked one on top of the other. An automated guided vehicle according to any one of claims 1 to 4, wherein when the front of the robot is defined as the surface with the robot arms arranged on both sides, there are two such surfaces, a front and a back, and the movement of the robot arm is restricted to one of the two surfaces, and the surface on which the robot arm can move is defined as the front of the robot, the direction of the front of the robot when lifting a load from a load area and the direction of the front of the robot when loading the lifted load onto a loading platform can be changed. A method for transporting luggage using an unmanned guided vehicle having a robot arm and a loading platform mounted on the vehicle body, the loading platform having a horizontal rotation axis and a wide surface portion and a narrow surface portion arranged in an L-shape in a cross section perpendicular to the rotation axis, and the loading platform is rotated by the robot arm so that the area of the wide surface portion of the loading platform when viewed from above is larger when loading and unloading than when the platform is empty or when luggage is being transported . 7. A transport method according to claim 6, wherein the platform is rotated by the robot arm so that the area of the broad surface of the platform in a top view during transport of the luggage is reduced compared to when the luggage is loaded and unloaded. A transportation method as described in claim 6 or 7, wherein the robot arm directly acts on the loading platform to reduce the top view area of the wide surface of the loading platform, and when the robot arm releases the action , the loading platform rotates due to gravity, thereby expanding the top view area of the wide surface of the loading platform.

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