JP2023146715A - Unloading device - Google Patents

Abstract

To realize a technique that can appropriately detect an article on a top shelf and reflect it in an unloading operation in an unloading device that sucks a topmost group of articles and separates them from a group of articles stacked below.SOLUTION: An unloading device 1 includes a suction device 2 including a suction section 21, a lifting device, a control device, and an article detection device 5 that detects an article W crossing a detection surface 13 set parallel to a suction surface 21a at a position spaced downward by a specific distance L with respect to the suction surface 21a, wherein the control device obtains control information for calculating a relative distance M, and calculates the relative distance M, and stops the lifting device when the article detection device detects the article W in a suction approach state even though the relative distance M is greater than the specific distance L by more than a determination threshold Q.SELECTED DRAWING: Figure 9

Description

The present invention relates to an unloading device that separates a target article group, which is a plurality of articles belonging to the top tier, from a stacked article group, which is a plurality of articles stacked on a loading section.

An example of the above-mentioned unloading device is disclosed in Japanese Patent Laid-Open No. 2002-128275 (Patent Document 1). Hereinafter, in the description of the background art, the symbols shown in parentheses are those of Patent Document 1.

The unloading device (picking device 1) of Patent Document 1 includes a clamp mechanism (2) and a lifting device (lifter 10). A plurality of articles (commodities 6) are stacked on the lifting device via a pallet (P), and the topmost tier or a group of articles in multiple tiers from above is picked by a clamp mechanism (2). Specifically, by raising the elevating device (10), a group of articles on an arbitrary stage is placed at a position corresponding to the pressing tool (7) of the clamp mechanism (2). The group of articles in this arbitrary stage is then held between two pairs of pressing tools (7). When the elevating device (10) descends in this state, the group of articles from the top to an arbitrary level is separated from the group of articles at the lower level.

By the way, in a stacked article group in which a plurality of articles are stacked, adjacent articles may be adhered to each other with glue or the like to prevent the articles from collapsing. In such a case, some of the items in the group of items held by the pressing tool (7) may remain on the lifting device without being separated from the group of stacked items below. . The unloading device of Patent Document 1 is configured to detect items remaining without being separated by providing a residual sensor (22) below the pressing tool (7).

Japanese Patent Application Publication No. 2002-128275

The unloading device of Patent Document 1 includes the clamp mechanism (2) as described above, and is configured to clamp a group of articles in an arbitrary stage from the sides. On the other hand, some unloading devices are configured to attract the upper surface of the uppermost group of articles using a suction section to separate the uppermost group of articles from the lowermost stacked articles. In such an unloading device, if some items on the top shelf remain without being separated, in the next unloading operation, the suction unit that approaches the group of stacked items from above and the remaining items There is a risk of collision. In addition to cases where some items remain, for example, if there is an error in the information indicating the positional relationship between the top group of items and the suction unit, in other words, the recognized stacking A similar problem may occur if there is an error in the number of stages in the group of articles, the height of the articles, etc.

Therefore, in an unloading device that adsorbs a group of articles on the top shelf and separates them from a group of stacked articles below, it is necessary to realize a technology that can appropriately detect the articles on the top shelf and reflect this in the unloading operation. desired.

The unloading device according to the present disclosure is an unloading device that separates a target article group, which is a plurality of articles belonging to the top layer, from a stacked article group, which is a plurality of articles stacked on a stacking section. There it is,
a suction device including a suction section that suctions the upper surface of the target article group to hold the target article group; an elevating device that relatively raises and lowers the placement section and the suction section; the suction device and the suction device; A control device for controlling the lifting device;
A surface in contact with the upper surface of the target article group in the suction part is an adsorption surface,
further comprising an article detection device that detects the article crossing a detection surface set parallel to the suction surface at a position spaced apart by a specific distance below the suction surface;
The control device includes:
obtaining control information for calculating a relative distance that is a distance between the top surface of the target article group and the suction surface, and determining the relative distance;
In a suction approach state in which the suction unit is not suctioning the article and the lifting device is operated to reduce the relative distance, the relative distance is greater than the specific distance by a determination threshold or more. However, if the article detection device detects the article, the lifting device is stopped.

According to this configuration, since the article detection device is provided that detects an article that crosses the detection surface set parallel to the suction surface at a position spaced apart by a specific distance below the suction surface, the suction portion It is possible to appropriately detect an article approaching the suction part when the object is not suctioning an article and the upper surface of the target article group and the suction part are approaching for suction. If the article detection device detects an article even though the relative distance calculated based on the control information is greater than the specific distance by more than the determination threshold, that is, the article is located at a position where the article is not supposed to exist. If present, the lifting device can be stopped. Therefore, it is possible to reduce the possibility that at least one of the suction part and the article will be damaged due to collision between the suction part and the article.
As described above, according to the present configuration, it is possible to appropriately detect the article on the top shelf and reflect it in the unloading operation.

Further characteristics and advantages of the unloading device will become clear from the following description of an exemplary and non-restrictive embodiment with reference to the drawings.

Plan view of article transfer equipment Front view of unloading device and stacked goods group Plan view schematically showing the article detection device and optical axis A front view schematically showing a suction device and a group of stacked articles. A front view schematically showing a suction device and a group of stacked articles in a suction approach state when the unloading operation is performed normally. A front view schematically showing the suction device and the stacked article group in a state where the target article group is suctioned when the unloading operation is performed normally. A front view schematically showing a suction device and a group of stacked articles in a state of being separated after suction is released when unloading operation is performed normally. A front view schematically showing a suction device and a group of stacked articles when the unloading operation becomes abnormal. A front view schematically showing a suction device and a group of stacked articles in a suction approach state when the unloading operation becomes abnormal. A front view schematically showing a suction device and a group of stacked articles in a state of being separated after suction has been released when the unloading operation becomes abnormal. Control block diagram Flowchart showing control by control device

1. Overall Overview Below, an example in which the unloading device 1 is applied to article transfer equipment will be described based on the drawings. In this embodiment, as shown in FIG. 1, the article transfer equipment includes an unloading device 1, a conveyance device 6, and an automatic warehouse (not shown). In this example, the unloading device 1 transfers the plurality of articles W taken out from the automated warehouse from the first prescribed position 31 to the second prescribed position 32. The transport device 6 transports the plurality of articles W taken out from the automated warehouse to the first prescribed position 31, and carries out the plurality of articles W located at the second prescribed position 32 to the outside of the article transfer facility. In this example, the direction in which the first specified position 31 and the second specified position 32 are lined up is the transfer direction X, one side of the transfer direction X is the first transfer direction side X1, and the The other side is defined as a second side in the transfer direction X2. Further, the direction perpendicular to the transfer direction X when viewed in the vertical direction is defined as the orthogonal direction Y. In the illustrated example, the first specified position 31 is arranged on the first side X1 in the transfer direction with respect to the second specified position 32.

In this example, as shown in FIGS. 1 and 2, the conveyance device 6 includes a first conveyor 6a and a second conveyor 6b. The first conveyor 6a transports a plurality of articles W from the automated warehouse to the first specified position 31. Further, the first conveyor 6a transports the remaining articles W that have not been transferred by the unloading device 1 at the first specified position 31 from the first specified position 31 to the automated warehouse. The second conveyor 6b transports the plurality of articles W transferred from the first prescribed position 31 to the second prescribed position 32 from the second prescribed position 32 to the outside of the article transfer facility. Note that the destination of the article W by the second conveyor 6b may be an automated warehouse.

As shown in FIGS. 1, 2, 4, and 7, a plurality of articles W stacked on a pallet P (hereinafter referred to as stacked article group Wt) are located at the first specified position 31. Placed. Similarly, a plurality of articles W stacked on a pallet P are also arranged at the second specified position 32. The stacked article group Wt placed on the pallet P is conveyed to the first specified position 31 by the first conveyor 6a. Then, the unloading device 1 separates the necessary number of stages of articles W from the stacked article group Wt at the first prescribed position 31 and transfers them onto the pallet P at the second prescribed position 32. That is, at the second specified position 32, a plurality of articles W are stacked on the pallet P by the unloading device 1, thereby forming a stacked article group Wt. Here, the article W is a container with a lid, and various items such as food, drinking water, and mechanical parts are stored therein. In this embodiment, the plurality of articles W belonging to one stacked article group Wt are containers having the same shape and size. In the illustrated example, the article W is a cardboard box.

2. Unloading Device As shown in FIG. 4, FIG. 5, and FIG. The target article group Ws, which is a plurality of articles W to which it belongs, is separated. In this embodiment, the unloading device 1 lifts the target article group Ws relative to the stacked article group Wt below it. Thereby, the unloading device 1 separates the target article group Ws from the stacked article group Wt below it. Here, in this embodiment, the target article group Ws is all the articles W belonging to the top row of the stacked article group Wt. In this example, the unloading device 1 lifts the target article group Ws at the first specified position 31 relative to the stacked article group Wt below it. In this embodiment, the mounting section 3 is a pallet P. Note that the placement section 3 may be any device that forms a placement surface on which the stacked article group Wt is placed, and may be, for example, a lifting platform of a lifter, a conveyance surface of a conveyor, or the like. That is, the article W does not necessarily need to be placed on the pallet P. In the illustrated example, the pallet P serving as the placement unit 3 is placed on the first conveyor 6a at the first specified position 31. Further, in this embodiment, the pallet P is also placed on the second conveyor 6b at the second specified position 32. Below, the specific configuration of the unloading device 1 will be explained.

As shown in FIGS. 1, 2, and 11, the unloading device 1 includes a suction device 2 including a suction section 21 that suctions the upper surface 11 of the target article group Ws and holds the target article group Ws, and a loading device 2. It includes a lifting device 4 that relatively raises and lowers the placement unit 3 and the suction unit 21, and a control device 100 that controls the suction device 2 and the lifting device 4.

2-1. Lifting device In this embodiment, as shown in FIGS. 2, 4, 5, 6, and 7, the lifting device 4 is configured to move the suction section 21 at least in the vertical direction. Thereby, the lifting device 4 can lift the suction section 21 that has suctioned the articles W included in the target article group Ws relative to the placement section 3. In this example, as shown in FIGS. 1 and 2, the lifting device 4 is included in the robot 40. In the illustrated example, the robot 40 includes a pedestal section 41, a rotating section 42, and a robot arm 46 (first arm 43, second arm 44). The pedestal portion 41 is fixed to the pedestal 39. The rotating part 42 is rotatably supported by the pedestal part 41 around an axis extending in the vertical direction. A base end portion of the first arm 43 is swingably connected to the rotating portion 42 . A base end of the second arm 44 is swingably connected to a distal end of the first arm 43. The suction device 2 is connected to the tip of the second arm 44. As described above, in the present embodiment, the lifting device 4 (robot 40) does not raise and lower the placing portion 3 (stacked article group Wt), but by raising and lowering the suction device 2, the lifting device 4 (robot 40) The suction section 21 is moved up and down relative to the suction section 21.

2-2. Adsorption Apparatus In this embodiment, as shown in FIG. 2, the adsorption apparatus 2 includes an adsorption section 21, an adsorption support section 22, and a connecting section 23. In this example, the suction support section 22 supports the suction section 21 . In this example, the suction support section 22 supports a plurality of suction sections 21 (suction pads) arranged in a plane from above. The connecting portion 23 connects the suction support portion 22 to the robot 40. In the illustrated example, the base end portion of the connecting portion 23 is swingably connected to the distal end portion of the second arm 44 of the robot 40. The tip of the connecting portion 23 is fixed to the surface of the suction support portion 22 facing upward. The suction unit 21 and the suction support unit 22 are integrally moved within a specified range (in the illustrated example , within the movable range of the robot arm 46). Thereby, the unloading device 1 can transfer the target article group Ws held by the suction unit 21 from the first prescribed position 31 to the second prescribed position 32. Note that the suction device 2 may not include the suction support portion 22 and the connection portion 23, and the suction portion 21 may be directly connected to the tip of the second arm 44.

In this embodiment, as shown in FIGS. 2, 3, and 4, a plurality of suction parts 21 are supported by a suction support part 22. More specifically, each of the plurality of suction sections 21 is provided so as to be lined up in a plane along the downwardly facing surface of the suction support section 22 . In this embodiment, the suction section 21 is configured to be elastically deformable in the vertical direction. In this example, the suction unit 21 is a suction pad. That is, the suction part 21 is formed in a bellows shape that can be expanded and contracted in the vertical direction. In this case, the lower surface of the suction pad as the suction part 21 becomes the suction surface 21a that is in contact with the upper surface 11 of the target article group Ws. Therefore, in this example, the position of the suction surface 21a changes with respect to the suction support section 22 and the article detection device 5 in accordance with the deflection of the suction pad. In this embodiment, since the plurality of suction parts 21 are arranged in a plane, the collection of the lower surfaces of the plurality of suction parts 21 forms the suction surface 21a. A valve (not shown) and a suction device (not shown) such as a pump are connected to the suction unit 21 via a tube (not shown). The control device 100 switches the state of the suction unit 21 between a suction state in which the article W is suctioned and a suction release state in which the article W is not suctioned, by controlling a valve. In addition, in this example, each of the plurality of suction parts 21 has the same structure.

2-3. Article Detection Device As shown in FIGS. 3, 4, 5, and 11, the unloading device 1 further includes an article detection device 5. As shown in FIGS. 5, 9, and 10, the article detection device 5 specifies the surface of the suction unit 21 that is in contact with the upper surface 11 of the target article group Ws as the suction surface 21a, and specifies the surface below the suction surface 21a. The article W crossing the detection surface 13 set parallel to the suction surface 21a at a position separated by a distance L is detected. In this embodiment, the relative position of the article detection device 5 with respect to the suction support section 22 is fixed. Therefore, the relative position between the article detection device 5 and the suction section 21 is also fixed unless the deflection of the suction section 21 is taken into account. Therefore, the article detection device 5 is connected to the suction section 21 so as to move up and down integrally. In this way, the article detection device 5 moves integrally with the suction unit 21 at least in the vertical direction to detect an article that intersects with the detection surface 13 at a position spaced downward by a specific distance L with respect to the suction surface 21a. Detect W. In this example, the specific distance L is a distance based on the suction surface 21a when the suction portion 21 is not bent. Details of the specific distance L will be described later.

In this example, as shown in FIG. 3, the article detection device 5 is configured using a transmission type optical sensor 50. Therefore, this optical sensor 50 includes a light projecting section 51 and a light receiving section 52. The plurality of light projecting sections 51 and the plurality of light receiving sections 52 are arranged on both sides with the plurality of suction sections 21 in between. In the illustrated example, the plurality of light projecting sections 51 and the plurality of light receiving sections 52 are arranged separately on both sides of the plurality of suction sections 21 in the transfer direction X. Further, the article detection device 5 includes a pair of detection support parts 53. The plurality of light projecting sections 51 and light receiving sections 52 are fixed to the suction support section 22 via a pair of detection support sections 53.

As shown in FIG. 3, each of the plurality of light projectors 51 and the plurality of light receivers 52 is arranged to form a plurality of optical axes R along the detection surface 13. In this example, as shown in FIG. 3, the plurality of optical axes R are arranged along the transfer direction X on the detection surface 13. Here, a plurality of optical axes R are arranged so as to be spaced apart from each other in the orthogonal direction Y. In the illustrated example, there are six optical axes R, but it may be less than six or more than six. Further, unlike the illustrated example, the plurality of light emitting sections 51 and the plurality of light receiving sections 52 are arranged with respect to the plurality of adsorption sections 21 so that the plurality of optical axes R are arranged along the orthogonal direction Y. They may be arranged on both outer sides in the orthogonal direction Y. In this example, the article detection device 5 is a transmissive type optical sensor 50, but a reflective type optical sensor 50 in which a light emitting part and a light receiving part are integrated is placed on one side in the transfer direction X. In addition, a reflecting plate may be provided on the other side in the transfer direction X. Further, for example, the article detection device 5 may be configured using a sensor other than an optical sensor, such as an imaging device or an ultrasonic sensor.

2-4. Height Detection Device In this example, as shown in FIGS. 1 and 11, the unloading device 1 includes a height detection device 7. The height detection device 7 is a device for detecting the height of the stacked article group Wt. In the present embodiment, the height detection device 7 is arranged in the middle of the conveyance path by the first conveyor 6a, and detects the height of the stacked article group Wt conveyed to the first specified position 31 by the first conveyor 6a. . Therefore, what is detected by the height detection device 7 is the initial height before the article W (target article group Ws) is separated from the stacked article group Wt. Initial state height information indicating the initial state height of this stacked article group Wt is output to the control device 100. Thereby, the control device 100 acquires initial state height information (control information 101) of the stacked article group Wt transported to the first specified position 31. Based on the height information, the unloading device 1 arranges the suction section 21 at a position corresponding to the target article group Ws of the stacked article group Wt.

2-5. Control Device In this embodiment, as shown in FIG. 11, a control device 100 is configured to execute arithmetic processing and various controls described later. The control device 100 is equipped with an arithmetic processing unit such as a CPU and peripheral circuits such as a memory, and the control device 100 is equipped with a peripheral circuit such as a memory. Each function is realized. In this example, the control device 100 controls the suction device 2, the robot 40 including the lifting device 4, the article detection device 5, and the height detection device 7.

As shown in FIG. 11, the control device 100 obtains the control information 101 for calculating the relative distance M, which is the distance between the upper surface 11 of the target article group Ws and the suction surface 21a, and calculates the relative distance M. The control device 100 acquires control information 101 from each of the suction device 2, the robot 40, the article detection device 5, and the height detection device 7. In this embodiment, the control device 100 acquires suction surface position information indicating the vertical position of the suction surface 21a of the suction unit 21 from the robot 40 (elevating device 4) as the control information 101. This suction surface position information is obtained from the position of the tip of the second arm 44 as control information of the robot 40 and the distance (constant) from the tip to the suction surface 21a. Further, the control device 100 acquires detection information from the article detection device 5, specifically information on whether or not the article W is detected by the optical sensor 50, as the control information 101. Further, as described above, the control device 100 acquires initial state height information indicating the initial state height of the stacked article group Wt as the control information 101. Further, the control device 100 receives, for control purposes, tier number information indicating the number of tiers of the stacked article group Wt located at the first specified position 31 from the management system 110 that manages information on a plurality of stacked article groups Wt in the article transfer equipment. Obtained as information 101. In addition, the control device 100 may be configured to obtain information such as the number of articles W constituting the stacked article group Wt, dimensions of the articles W, and types of articles W from the management system 110. good.

As shown in FIGS. 4 and 11, the control device 100 calculates the relative distance M from the initial state height information, the number of stages information, and the suction surface position of the stacked article group Wt transported to the first specified position 31. Calculate based on information. At this time, the control device 100 sets the value obtained by dividing the initial state height of the stacked article group Wt by the initial number of tiers as the article height H, and the value obtained by multiplying the article height H by the number of separated tiers as the separated height. , the value obtained by subtracting the separated height from the initial state height is calculated as the vertical dimension of the stacked article group Wt at the current moment. Here, the initial stage number is the number of stages in the initial state of the stacked article group Wt, and is included in the stage number information. The number of separated stages is the number of stages of the target article group Ws that has already been separated by the unloading device 1 from the stacked article group Wt in the initial state (hereinafter referred to as "the number of separated stages"). Information on the number of separated stages is acquired from the operation history of the unloading device 1 included in the control device 100. Then, the control device 100 obtains the distance in the vertical direction between the top surface of the placing section 3 and the suction surface 21a from the suction surface position information, and calculates the vertical distance between the stacked article group Wt at the current time calculated as described above from the distance. The value obtained by subtracting the dimension in the direction is calculated as the relative distance M.

Note that the control information 101 may be configured to be acquired from a control device or control system higher than the control device 100. Below, the control of the control device 100 in the unloading operation will be specifically explained. Note that FIGS. 4 to 7 show the unloading operation in a normal state. 8 to 10 show the unloading operation in a state where an abnormality has occurred.

As shown in FIG. 9, the control device 100 controls the relative distance M when the suction unit 21 is not suctioning the article W and the elevating device 4 is operated to reduce the relative distance M. If the article detection device 5 detects the article W even though the distance L is greater than the specific distance L by the determination threshold Q or more, the lifting device 4 is stopped. In this embodiment, the vertical dimension of the article W having the largest vertical dimension is set as the maximum vertical dimension, and the control device 100 determines that when the suction unit 21 is not suctioning the article W, the relative distance M is the maximum vertical dimension. By executing the adsorption approach process in which the elevating device 4 is operated to gradually decrease the relative distance M from a state where the relative distance M is larger than the sum of the dimension and the specific distance L, the adsorption approach state is set. In this example, the control device 100 controls the robot 40 (elevating device 4) to move the plurality of suction parts 21 to the first reference position E at the first specified position 31 (see FIGS. 4 and 8). . Here, the first reference position E is a position that overlaps the pallet P at the first specified position 31 (or the stacked article group Wt on the pallet P) in the vertical direction, and the relative distance M is the maximum vertical dimension. This position is larger than the sum of the specified distance L and the specific distance L by a specified margin distance. In other words, the first reference position E is a position higher than the upper surface 11 of the target article group Ws, which is the top of the stacked article group Wt, by the total distance of the maximum vertical dimension, the specific distance L, and the margin distance. Further, at the first reference position E, the suction surface 21a is arranged parallel to the upper surface 11 of the target article group Ws. Note that the maximum vertical dimension is the vertical dimension of the article W having the largest vertical dimension among the articles W constituting the stacked article group Wt. Here, the margin distance is preferably set to be larger than the maximum value of the vertical positional error of the suction surface 21a by the robot 40 (elevating device 4). In this example, the maximum value of the vertical position error of the suction surface 21a by the robot 40 (elevating device 4) and the maximum error of the detected value of the height of the stacked article group Wt detected by the height detection device 7 are determined. It is set to a value that corresponds to the sum of the values. By setting the margin distance in this way, when an article W that should not exist above the target article group Ws (hereinafter referred to as "abnormal article Wa") exists, the vertical direction of the robot 40 (elevating device 4) Even if the positional error is maximum on the lower side, the detection surface 13 of the article detection device 5 is placed above the abnormal article Wa with the suction part 21 placed at the first reference position E. will be done. Therefore, execution of the suction approach process can be started from a state in which the article detection device 5 has not detected the abnormal article Wa.

Then, as shown in FIGS. 4 and 5, the control device 100 lowers the plurality of suction sections 21 from the first reference position E, thereby moving these suction sections 21 onto the upper surface of the stacked article group Wt (target The object is brought close to the upper surface 11) of the article group Ws. This state is the approaching state for suction, and in the approaching state for suction, the relative distance M decreases. Then, when the article detection device 5 detects the article W in the suction approach state and the relative distance M is greater than the specific distance L by more than the determination threshold Q, the control device 100 detects the article W in the suction approach state. The robot 40 (elevating device 4) is controlled to stop the lowering of the robot 21. The article W detected in this way is an abnormal article Wa that should not exist on the target article group Ws. In this example, when the robot 40 (elevating device 4) stops descending in this way, it is assumed that the unloading operation has become abnormal, and an abnormality is notified. The abnormality is notified by, for example, outputting an abnormality alarm sound from a speaker or a buzzer, turning on an abnormality indicator light, or notifying a terminal operated by the user of abnormality information. Because of this configuration, even if some articles W belonging to the target article group Ws remain without being separated from the stacked article group Wt on the lower level, the next unloading The descending of the suction section 21 can be stopped by detecting the article W remaining during the operation. Therefore, it is possible to avoid a situation where the adsorption section 21 and the abnormal article Wa collide. Further, even if there is an error in the control information 101, such a situation can be avoided. For example, if the initial number of stages is "M stages" and the number of separated stages by the unloading device 1 is correctly "N stages", but the control device 100 incorrectly recognizes it as "N+1 stages", The control device 100 recognizes the number of stages of the stacked article group Wt as "MN-1 stage" which is smaller than the actual "MN stage". Even in such a case, the control device 100 can detect the "MN" (uppermost) article W in the unloading operation and stop the lowering of the suction unit 21. Therefore, it is possible to avoid a situation where the adsorption section 21 and the abnormal article Wa collide. Note that the reason why the number of separated stages recognized by the control device 100 is an incorrect value may be due to, for example, recovery processing after an abnormal situation such as a power outage.

As described above, in this embodiment, the vertical position of the stacked article group Wt at the first specified position 31 is not changed, and the suction section 21 (more specifically, the suction section 21 and the suction support section 22) is stacked. By lowering it toward the article group Wt, it enters a state in which it is approaching for suction. In the present embodiment, the control device 100 enables the article detection device 5 at least during execution of the suction approach process. More specifically, the control device 100 enables the optical sensor 50 of the article detection device 5 at the time when the suction surface 21a of the suction section 21 starts to descend from the first reference position E.

Here, the determination threshold Q is preferably set to be larger than the maximum value of the vertical position error of the suction surface 21a by the robot 40 (elevating device 4). In this example, the maximum value of the vertical position error of the suction surface 21a by the robot 40 (elevating device 4) and the maximum error of the detected value of the height of the stacked article group Wt detected by the height detection device 7 are determined. It is set to a value that corresponds to the sum of the values. Moreover, the determination threshold Q is set to be less than the minimum vertical dimension, assuming that the vertical dimension of the article W having the smallest vertical dimension is the minimum vertical dimension. This avoids a situation where the article detection device 5 mistakenly detects the target article group Ws that is properly stacked as an abnormal article Wa and the control device 100 stops the robot 40 (lifting device 4). can.

In this embodiment, the amount of decrease in the relative distance M from when the control device 100 outputs a stop command to stop the lifting device 4 until the lifting device 4 actually stops is defined as the required stopping distance, and the required stop distance is defined as the required stop distance. The specific distance L is set to be greater than or equal to the required stopping distance minus the elastic deformation margin, with the amount of elastic deformation possible in the vertical direction being the elastic deformation margin. As a result, after the article detection device 5 detects the abnormal article Wa, the upper surface of the abnormal article Wa does not contact the suction section 21 or is in contact with the suction section 21 when the lifting device 4 is actually stopped. However, it can be made to fall within the range of elastic deformation of the suction portion 21. Therefore, it is possible to avoid crushing the abnormal article Wa by the suction part 21 and the suction support part 22. In this example, the specific distance L is set to a distance obtained by subtracting the elastic deformation allowance from the required stopping distance. This distance is the minimum specific distance L that can avoid crushing the abnormal article Wa by the suction part 21 and the suction support part 22. In the present embodiment, even in a normal state where no abnormal article Wa exists, when the article detection device 5 detects an article W, the control device 100 prevents the suction unit 21 from colliding with the target article group Ws. , the speed of the suction unit 21 is reduced, and the suction unit 21 is brought close to the target article group Ws at low speed. Therefore, as the specific distance L becomes longer, the cycle time of the unloading operation becomes longer. By setting the specific distance L to the minimum necessary distance, it becomes easier to keep the cycle time of the unloading operation short. Further, in this example, the vertical dimension of the article W having the smallest vertical dimension is taken as the minimum vertical dimension, and the specific distance L is set to be less than the minimum vertical dimension.

As shown in FIGS. 4, 5, and 6, in the present embodiment, the control device 100 is in the suction approach state, and the relative distance M is less than the sum of the specific distance L and the determination threshold Q. When the article detection device 5 detects the article W, the lifting device 4 is stopped after the suction surface 21a comes into contact with the upper surface 11 of the target article group Ws, and the upper surface 11 of the target article group Ws is suctioned by the suction unit 21. Thereafter, the elevating device 4 is operated to increase the distance between the upper surface of the placing section 3 and the suction surface 21a, and the target article group Ws is separated from the stacked article group Wt. When there is no abnormal article Wa on the target article group Ws and the unloading operation is performed normally, this normal operation is performed. In this example, at the first specified position 31, while the robot 40 (elevating device 4) is in the suction approach state in which the suction unit 21 is lowered at a constant speed, the article detection device 5 detects that the relative distance M is a specific distance L. When the article W is detected at a value less than the sum of the determination threshold value Q and the determination threshold value Q, the control device 100 reduces the descending speed of the suction unit 21. Then, when the suction surface 21a comes into contact with the upper surface 11 of the target article group Ws, the control device 100 stops the descent of the suction section 21. Then, the control device 100 causes the suction unit 21 (suction pad) to suction the upper surfaces 11 of all the articles W belonging to the target article group Ws, and then causes the robot 40 (elevating device 4 ) to work. As a result, the target article group Ws is lifted and separated from the stacked article group Wt below it.

Then, as shown in FIG. 6, the control device 100 is configured to move the suction surface 21a of the suction unit 21 to the second reference position of the second specified position 32 while holding the target article group Ws separated from the stacked article group Wt. The suction section 21 (more specifically, the plurality of suction sections 21 and suction support section 22) is moved so that it is placed at position F. The second reference position F is a position above the pallet P (or the stacked article group Wt placed on the pallet P) located at the second specified position 32. Then, the control device 100 lowers the suction unit 21 while holding the target article group Ws. Then, when the lower surface 12 of the target article group Ws comes into contact with the upper surface of the pallet P or the upper surface of the stacked article group Wt already placed on the pallet P, the suction section 21 stops descending. Next, the control device 100 controls the suction device 2 to release the suction by the suction unit 21 . After that, the control device 100 raises the suction section 21 and the suction support section 22. When the unloading operation is to be continued, the control device 100 controls the robot 40 (elevating device 4) to move the plurality of suction sections 21 and suction support sections 22 to the first reference position E.

In this embodiment, as shown in FIG. 10, the control device 100 operates the lifting device 4 to increase the relative distance M after the suction unit 21 releases the target article group Ws. If the article detection device 5 detects the article W even though the relative distance M is larger than the specific distance L by the determination threshold Q or more in the separation state after the suction is released, the lifting device 4 is stopped. In this example, as described above, the control device 100 lifts the suction parts 21 after releasing the suction of the target article group Ws by the plurality of suction parts 21. Here, if the article detection device 5 detects an article W even though the relative distance M is greater than the specific distance L by more than the determination threshold Q, at least some of the articles W belonging to the target article group Ws are It is presumed that it remains adsorbed by the adsorption part 21. That is, it is presumed that some of the articles W of the target article group Ws are not placed on the pallet P at the second specified position 32. Therefore, the control device 100 controls the robot 40 (elevating device 4) to stop the suction section 21 and the suction support section 22 from rising. In this example, when the robot 40 (elevating device 4) stops rising in this way, it is assumed that the unloading operation has become abnormal, and an abnormality is notified. The abnormality is notified by, for example, outputting an abnormality alarm sound from a speaker or a buzzer, turning on an abnormality indicator light, or notifying a terminal operated by the user of abnormality information.

3. Unloading Method The unloading method in this embodiment will be described below based on the flowchart shown in FIG. 12. In this example, the unloading device 1 separates the target article group Ws from the stacked article group Wt at the first prescribed position 31 and transfers the target article group Ws to the second prescribed position 32.

The control device 100 first acquires the control information 101 from the suction device 2, the robot 40 (lift device 4), and the height detection device 7 (S1). Then, the control device 100 executes a suction approach process in which the suction unit 21 is gradually lowered from the first reference position E (S2). For example, the suction section 21 is gradually lowered from the state shown in FIGS. 4 and 8. The control device 100 determines whether or not the article W is detected by the article detection device 5 while maintaining the suction approaching state (S3). When the article W is not detected by the article detection device 5 (S3: No), the control device 100 continues to execute the suction approach process to maintain the suction approach state (S2). When the article W is detected by the article detection device 5 (S3: Yes), the control device 100 determines whether the relative distance M is less than the sum of the specific distance L and the determination threshold Q (M<L+Q). Determine (S4). Then, when the control device 100 determines that the relative distance M is not less than the sum of the specific distance L and the determination threshold Q (S4: No), that is, the relative distance M is equal to the specific distance L and the determination threshold If it is determined that the total value is equal to or greater than the sum of Q, the lowering of the suction unit 21 is stopped (S15). In the example shown in FIG. 8, in the suction approach state, the detection surface 13 of the article detection device 5 is , a state in which the article W is located above the upper surface of the remaining article W is shown. When the suction section 21 is gradually lowered from this state, a state as shown in FIG. 9 is obtained. FIG. 9 shows a state in which the relative distance M is larger than the specific distance L plus the determination threshold Q (M>L+Q), and the article detection device 5 detects the article W remaining above the target article group Ws. Indicates the detected state.

When the control device 100 detects the article W by the article detection device 5 and determines that the relative distance M is less than the sum of the specific distance L and the determination threshold Q (S4: Yes), the control device 100 determines that the article is normal. Execute the time action. That is, the control device 100 reduces the descending speed of the suction unit 21 and causes the suction unit 21 to approach the target article group Ws at a low speed (S5). The example in FIG. 5 shows a state in which the article W is detected by the article detection device 5 when the relative distance M is less than the sum of the specific distance L and the determination threshold Q (M<L+Q).

After that, the control device 100 determines whether the suction surface 21a of the suction unit 21 has contacted the upper surface 11 of the target article group Ws (S6). When the control device 100 determines that the suction surface 21a is not in contact with the upper surface 11 (S6: No), the control device 100 lowers the suction section 21 at a low speed. On the other hand, when the control device 100 determines that the suction surface 21a has contacted the upper surface 11 (S6: Yes), the control device 100 stops the suction section 21. Then, the control device 100 switches the suction unit 21 from the suction release state to the suction state and controls the suction device 2 to suction the target article group Ws (S7). After that, the control device 100 raises the suction unit 21 to separate the target article group Ws from the stacked article group Wt below it (S8). FIG. 6 shows a state in which the target article group Ws is separated from the stacked article group Wt below it.

After that, the control device 100 moves the suction-held target article group Ws onto the pallet P at the second specified position 32 (or above the stacked article group Wt stacked on the pallet P) (S9). Then, when the target article group Ws is placed on the pallet P or the stacked article group Wt on the pallet P, the control device 100 switches the suction unit 21 from the suction state to the suction release state (S10). After that, the control device 100 executes a separation process after attraction is released (S11). Specifically, the control device 100 raises the suction unit 21 to separate the suction unit 21 from the target article group Ws (or the stacked article group Wt).

Then, the control device 100 determines whether the relative distance M is greater than or equal to the sum of the specific distance L and the determination threshold Q (M≧L+Q) while executing the separation process after the attraction is released (S12). . The control device 100 maintains the separation state after the attraction is released (S12) until the relative distance M becomes equal to or greater than the sum of the specific distance L and the determination threshold Q (S12: No). When the control device 100 determines that the relative distance M is greater than or equal to the sum of the specific distance L and the determination threshold Q (S12: Yes), the control device 100 determines whether or not the article W is detected by the article detection device 5 (S13). ). When the article W is detected by the article detection device 5 (S13: Yes), the control device 100 determines that the article W is not properly separated from the suction section 21 and stops the suction section 21 from rising. (S15). FIG. 10 shows a state in which the relative distance M is larger than the specific distance L plus the determination threshold Q (M>L+Q), and the article W still being sucked by the suction unit 21 is detected. An example of the condition is shown. Further, when the article W is not detected by the article detection device 5, the control device 100 moves the suction unit 21 to the initial position, here the first reference position E, as shown in FIG. 4 (S14). The two-dot chain line in FIG. 7 indicates a state in which the relative distance M is greater than or equal to the sum of the specific distance L and the determination threshold Q, and the article W is not detected by the article detection device 5. In this way, if the relative distance M is greater than or equal to the sum of the specific distance L and the determination threshold Q and the article W is not detected by the article detection device 5, all the articles W belonging to the target article group Ws are detected according to the second rule. It is estimated that it was separated from the adsorption part 21 at position 32. With the above, the control device 100 ends the transfer process of the target article group Ws.

4. Other Embodiments Next, other embodiments of the unloading device will be described.

(1) In the above embodiment, by raising and lowering the suction part 21 while fixing the vertical position of the placing part 3 (stacked article group Wt), the placing part 3 and the suction part 21 are moved relative to each other. The explanation has been given using an example of a configuration in which the vehicle is raised and lowered. However, without being limited to such a configuration, for example, by raising and lowering the placement section 3 (stacked article group Wt) while fixing the vertical position of the suction section 21, the placement section 3 and the suction can be moved up and down. It is good also as a structure which raises and lowers the part 21 relatively. In this case, for example, a structure may be adopted in which a lifter is installed at the first specified position 31, a pallet P serving as the placing section 3 and a group of stacked articles Wt are placed on the lifter, and these are moved up and down.

(2) In the above embodiment, the control device 100 is in the suction approach state, and the article detection device 5 detects the article W when the relative distance M is less than the sum of the specific distance L and the determination threshold Q. In this case, a configuration has been described as an example in which a normal operation is performed in which the lifting device 4 is stopped after the suction surface 21a comes into contact with the upper surface 11 of the target article group Ws. However, it is not limited to such a configuration. For example, if the vertical position error of the suction surface 21a by the robot 40 (elevating device 4) is small enough to be ignored, the determination threshold Q may be set to zero. In this case, the control device 100 is configured to perform normal operation when the article detection device 5 detects the article W while the relative distance M is less than the specific distance L (M<L) while in the suction approach state. It's good as well.

(3) In the above embodiment, the case where the suction part 21 is configured to be elastically deformable in the vertical direction, such as a suction pad, has been described as an example. However, the present invention is not limited to such a configuration, and a configuration in which the suction portion 21 does not deform in the vertical direction may be adopted. For example, instead of having a bellows shape, the suction portion 21 may be a suction pad in which the suction surface 21a does not bend. Further, for example, when the article W has a portion made of a magnetic material such as iron, the attraction section 21 may be configured to attract the article W using magnetic force. In this case, it is preferable that the adsorption section 21 includes a permanent magnet or an electromagnet.

(4) In the above embodiment, the control device 100 determines the relative distance M from a state where the relative distance M is larger than the sum of the maximum vertical dimension and the specific distance L when the suction unit 21 is not suctioning the article W. The explanation has been given as an example of a configuration in which the lifting device 4 is operated so as to gradually decrease the amount. However, without being limited to such a configuration, the initial state in which the relative distance M is gradually reduced may be set to a state where the relative distance M is less than or equal to the sum of the maximum vertical dimension and the specific distance L. Even in this case, it is sufficient that the initial state in which the relative distance M is gradually reduced is a state in which the suction unit 21 does not interfere with the abnormal article Wa present on the target article group Ws.

(5) In the above embodiment, the control device 100 detects the article W even though the relative distance M is larger than the specific distance L by more than the determination threshold Q in the separating state after the attraction is released. The explanation has been given as an example of a configuration in which the elevating device 4 is stopped when the elevating device 4 is detected. However, without being limited to such a configuration, the control device 100 may be set so that the article detection device 5 does not detect the article W in the separation state after the attraction is released.

(6) In the above embodiment, the robot 40 includes a robot arm 46 (a first arm 43, a second arm 44, and a third arm 45), which moves the suction unit 21 into a specified space. The explanation has been given using an example of a configuration that allows for flexible operation. However, the robot 40 is not limited to such a configuration, and the robot 40 may be a three-axis robot equipped with a movement mechanism that moves the suction unit 21 in each of three directions: the transfer direction X, the orthogonal direction Y, and the vertical direction. It may be configured as follows.

(7) In the above embodiment, the configuration in which the lifting device 4 is included in the robot 40 has been described as an example, but the invention is not limited to this. The elevating device 4 may be constituted by a vertical movement mechanism (lifter) that only moves the suction section 21 up and down. Further, as described above, the elevating device 4 may be constituted by a vertical movement mechanism (lifter) that only moves up and down the placing section 3 (stacked article group Wt). Alternatively, the elevating device 4 may be configured by a vertical movement mechanism that moves both the suction section 21 and the placing section 3 up and down.

(8) The configurations disclosed in each of the above-mentioned embodiments (including the above embodiments and other embodiments; the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments unless there is a conflict. It is also possible to do so. Regarding other configurations, the embodiments disclosed in this specification are illustrative in all respects, and can be modified as appropriate without departing from the spirit of the present disclosure.

5. Outline of the above-mentioned embodiment Hereinafter, an outline of the unloading device explained above will be explained.

The unloading device according to the present disclosure is an unloading device that separates a target article group, which is a plurality of articles belonging to the top layer, from a stacked article group, which is a plurality of articles stacked on a stacking section. There it is,
a suction device including a suction section that suctions the upper surface of the target article group to hold the target article group; an elevating device that relatively raises and lowers the placement section and the suction section; the suction device and the suction device; A control device for controlling the lifting device;
A surface in contact with the upper surface of the target article group in the suction part is an adsorption surface,
further comprising an article detection device that detects the article crossing a detection surface set parallel to the suction surface at a position spaced apart by a specific distance below the suction surface;
The control device includes:
obtaining control information for calculating a relative distance that is a distance between the top surface of the target article group and the suction surface, and determining the relative distance;
In a suction approach state in which the suction unit is not suctioning the article and the lifting device is operated to reduce the relative distance, the relative distance is greater than the specific distance by a determination threshold or more. However, if the article detection device detects the article, the lifting device is stopped.

According to this configuration, since the article detection device is provided that detects an article that crosses the detection surface set parallel to the suction surface at a position spaced apart by a specific distance below the suction surface, the suction portion It is possible to appropriately detect an article approaching the suction part when the object is not suctioning an article and the upper surface of the target article group and the suction part are approaching for suction. If the article detection device detects an article even though the relative distance calculated based on the control information is greater than the specific distance by more than the determination threshold, that is, the article is located at a position where the article is not supposed to exist. If present, the lifting device can be stopped. Therefore, it is possible to reduce the possibility that at least one of the suction part and the article will be damaged due to collision between the suction part and the article.
As described above, according to the present configuration, it is possible to appropriately detect the article on the top shelf and reflect it in the unloading operation.

Here, when the control device is in the adsorption approach state and the article detection device detects the article when the relative distance is less than the sum of the specific distance and the determination threshold, After the suction surface comes into contact with the top surface of the target article group, the lifting device is stopped, the suction section is made to suction the top surface of the target article group, and then the distance between the top surface of the placement section and the suction surface is It is preferable to operate the lifting device so as to increase the number of objects, thereby separating the target article group from the stacked article group.

According to this configuration, when there is no article remaining at the top of the stacked article group and the control information is correct, the target article group can be appropriately separated from the stacked article group below it.

Further, the suction part is configured to be elastically deformable in the vertical direction,
The amount of decrease in the relative distance from when the control device outputs a stop command to stop the lifting device until the lifting device actually stops is defined as the required stopping distance, and elastic deformation of the suction portion in the vertical direction is performed. Assuming the possible amount as the elastic deformation amount,
Preferably, the specific distance is set to be greater than or equal to the distance required for stopping minus the elastic deformation allowance.

According to this configuration, even if the lifting device cannot be stopped immediately after the control device outputs a command to stop the lifting device, the suction portion and the remaining article collide and at least one of the suction portion and the article is damaged. The possibility of damage can be reduced.

Further, the vertical dimension of the article having the largest vertical dimension is the maximum vertical dimension,
The control device is configured to control the lifting device so that the relative distance is gradually decreased from a state where the relative distance is larger than the sum of the maximum vertical dimension and the specific distance when the suction unit is not suctioning the article. It is preferable that the article is brought into the suction approaching state by executing a suction approach process in which the article is activated, and that the article detection device is enabled at least during execution of the suction approach process.

According to this configuration, even if there is an article that should not exist on the target article group based on the control information, the suction section is moved to the target article group while avoiding collision between the article and the suction section. can be gradually approached. Then, in the suction approach state in which the suction unit approaches the target article group, it is possible to appropriately detect the presence or absence of the article and the presence or absence of an abnormality in the control information.

Further, the control device may control the control device to control the target article group in a state in which the elevating device is operated to increase the relative distance after the adsorption of the target article group by the adsorption unit is released, and in a state in which If the article detection device detects the article even though the distance is greater than the specific distance by the determination threshold value or more, it is preferable to stop the lifting device.

According to this configuration, it is appropriately detected that at least some of the articles have not been separated from the suction part even though the article is in the separating state after the suction is released, and the lifting device is stopped. be able to. Therefore, while the article is being sucked to the suction section, the state is switched to the suction approach state for suction of the next target article group, and the article that is still being sucked to the suction section and the article belonging to the next target article group are separated. Collisions can be appropriately avoided.

Further, the lifting device moves the suction section at least in a vertical direction,
Preferably, the article detection device is connected to the suction section so as to move up and down integrally with the suction section.

According to this configuration, by moving the suction section in the vertical direction, it is possible to separate the target article group from the stacked article group below it, without raising or lowering the stacked article group itself. Therefore, compared to the case where a group of stacked articles is moved in the vertical direction, it is easier to suppress the increase in size of the unloading device. Furthermore, since the article detection device moves vertically together with the suction section, it is possible to appropriately detect the presence or absence of an article remaining as the suction section moves up and down.

The unloading device according to the present disclosure only needs to be able to achieve at least one of the above-mentioned effects.

2: Suction device 3: Placing section 4: Lifting device 5: Article detection device 11: Top surface 13: Detection surface 21: Suction section 21a: Suction surface 100: Control device 101: Control information L: Specific distance M: Relative distance Q: Judgment threshold value W: Article Ws: Target article group Wt: Stacked article group

Claims (6)

An unloading device that separates a target article group, which is a plurality of articles belonging to the top layer, from a stacked article group, which is a plurality of articles stacked on a stacking part, comprising:
a suction device including a suction section that suctions the upper surface of the target article group to hold the target article group; an elevating device that relatively raises and lowers the placement section and the suction section; the suction device and the suction device; A control device for controlling the lifting device;
A surface in contact with the upper surface of the target article group in the suction part is an adsorption surface,
further comprising an article detection device that detects the article crossing a detection surface set parallel to the suction surface at a position spaced apart by a specific distance below the suction surface;
The control device includes:
obtaining control information for calculating a relative distance that is a distance between the top surface of the target article group and the suction surface, and determining the relative distance;
In a suction approach state in which the suction unit is not suctioning the article and the lifting device is operated to reduce the relative distance, the relative distance is greater than the specific distance by a determination threshold or more. An unloading device that stops the lifting device when the article detection device detects the article. The control device is configured to control the suction surface when the article detection device detects the article while the relative distance is less than the sum of the specific distance and the determination threshold in the suction approaching state. stops the lifting device after contacting the top surface of the target article group, causes the suction section to suction the top surface of the target article group, and then increases the distance between the top surface of the placement section and the suction surface. The unloading device according to claim 1, wherein the lifting device is operated to separate the target article group from the stacked article group. The suction part is configured to be elastically deformable in the vertical direction,
The amount of decrease in the relative distance from when the control device outputs a stop command to stop the lifting device until the lifting device actually stops is defined as the required stopping distance, and elastic deformation of the suction portion in the vertical direction is performed. Assuming the possible amount as the elastic deformation amount,
The unloading device according to claim 1 or 2, wherein the specific distance is set to be greater than or equal to a distance obtained by subtracting the elastic deformation allowance from the required stopping distance. The vertical dimension of the article with the largest vertical dimension is the maximum vertical dimension,
The control device is configured to control the lifting device so that the relative distance is gradually decreased from a state where the relative distance is larger than the sum of the maximum vertical dimension and the specific distance when the suction unit is not suctioning the article. According to any one of claims 1 to 3, the article detection device is set to the suction approaching state by executing a suction approach process in which the article is operated, and the article detection device is enabled at least during execution of the suction approach process. Unloading equipment as described. The control device is configured to control whether the relative distance is in a state in which the elevating device is operated to increase the relative distance after the suction unit has released the target article group, and in a state where the lifting device is being operated to increase the relative distance. 5. The elevating device is stopped when the article detecting device detects the article even though the specific distance is greater than the determination threshold. Unloading equipment. The lifting device moves the suction section at least in the vertical direction,
The unloading device according to any one of claims 1 to 5, wherein the article detection device is connected to the suction section so as to move up and down integrally with the suction section.

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