Unloading equipment

Abstract

To provide an unloading apparatus for separating, by appropriately detecting an uppermost article and sucking an article group, a target article group from stacked article groups below.SOLUTION: The unloading apparatus comprises: a suction device 2 comprising a suction unit 21, a moving device, a control device, and an article detection device 5. The control device moves the suction unit 21 to a first side X1 in a specific direction with respect to a mounting unit 3 from a state where a vertical relative distance M is larger than one of an article height H and a specific distance L and smaller than that obtained by adding the specific distance L to the article height H and a detection line R is positioned on a second side X2 in the specific direction with respect to a target article group Ws until the detection line R is positioned on the first side X1 in the specific direction with respect to the target article group Ws, and inhibits an operation for bringing the suction unit 21 close to the target article group Ws in the vertical direction when the article detection device 5 detects an article W.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an unloading device that separates a group of target articles, which are a plurality of articles belonging to the top layer, from a group of stacked articles, which are a plurality of articles stacked on a loading section. [Background technology]

[0002] An example of such an unloading device is disclosed in Japanese Patent Laid-Open No. 2002-128275 (Patent Document 1). In the following description of the background art, the reference numerals in parentheses refer to those in Patent Document 1.

[0003] The unloading device (picking device 1) of Patent Document 1 includes a clamping mechanism (2) and a lifting device (lifter 10). A plurality of articles (products 6) are stacked on the lifting device via pallets (P), and the topmost or a plurality of uppermost article groups are picked by the clamping mechanism (2). Specifically, the lifting device (10) is raised to position an article group on an arbitrary layer in a position corresponding to the pressing tool (7) of the clamping mechanism (2). The article group on the arbitrary layer is then clamped between two pairs of pressing tools (7). When the lifting device (10) is lowered in this state, the article groups from the topmost layer to the arbitrary layer are separated from the article groups on the layers below.

[0004] In stacked goods containing multiple items, adjacent goods may be glued together with glue or the like to prevent the goods from falling over. In such cases, some of the goods clamped by the pressing tool (7) may not be separated from the goods stacked below and may remain on the lifting device. The unloading device of Patent Document 1 is configured to detect any remaining goods that have not been separated by providing a residual sensor (22) below the pressing tool (7). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-128275 Summary of the Invention [Problem to be solved by the invention]

[0006] The unloading device of Patent Document 1 is equipped with a clamping mechanism (2) as described above and is configured to clamp a stack of articles on any tier from the side. On the other hand, some unloading devices are configured to separate the top stack of articles from the stack of articles below by using a suction unit to suction the top surface of the top stack of articles. In such unloading devices, if some of the articles on the top stack remain without being separated, there is a risk that the remaining articles will collide with the suction unit approaching the stack of articles from above during the next unloading operation. In addition to cases where some of the articles remain, similar problems can occur, for example, when there is an error in the information indicating the positional relationship between the top stack of articles and the suction unit, i.e., when there is an error in the recognized number of tiers of the stack of articles or the height of the articles.

[0007] Therefore, in an unloading device that adsorbs the topmost stack of items and separates them from the stacks of items below it, it is desirable to realize technology that can properly detect the topmost stack of items and reflect this in the unloading operation. [Means for solving the problem]

[0008] The unloading device according to the present disclosure is an unloading device that separates a group of target articles, which are a plurality of articles belonging to the top layer, from a group of stacked articles, which are a plurality of articles stacked on a loading section, and a suction device having a suction section that suctions the upper surface of the target item group to hold the target item group; a moving device that moves the placement section and the suction section relatively in a specific direction along the horizontal direction and in an up-down direction; and a control device that controls the suction device and the moving device, one side of the specific direction is a specific direction first side, the other side of the specific direction is a specific direction second side, the direction along the horizontal direction and perpendicular to the specific direction is a specific width direction, the vertical dimension of the articles constituting the target article group is an article height, and the surface of the suction section that contacts the upper surface of the target article group is a suction surface, an article detection device that is spaced a specific distance below the suction surface and detects the article that crosses a detection line that is set along the specific width direction at a position adjacent to the suction surface on the first side in the specific direction, The control device acquires control information for calculating a vertical relative distance, which is the relative distance in the vertical direction between the upper surface of the target item group and the suction surface, and executes a specific direction movement process in which the movement device is operated to move the suction unit toward the specific direction first side relative to the placement unit from a state in which the vertical relative distance based on the control information is greater than the greater of the item height and the specific distance and is smaller than the length of the item height plus the specific distance, and the detection line is located on the specific direction second side relative to the target item group, until the detection line is located on the specific direction first side relative to the target item group; If the object detection device detects the object during the execution of the specific direction movement process, the operation of the movement device that moves the suction unit closer to the group of target objects in the vertical direction is prohibited.

[0009] According to this configuration, the detection line is moved in a specific direction along the top surface of the target item group while maintaining the vertical relative distance greater than the greater of the item height and the specific distance, and smaller than the length obtained by adding the specific distance to the item height, thereby enabling the presence or absence of items present above the top surface of the target item group to be properly detected. When such an object is detected, i.e., when an object is present in a position where no object should be present, the movement device is prohibited from moving the suction unit closer to the group of target objects in the vertical direction, thereby reducing the possibility of the suction unit colliding with the object and damaging at least one of the suction unit and the object. In this manner, with this configuration, the item on the top shelf can be properly detected and reflected in the unloading operation.

[0010] Further features and advantages of the unloading device will become apparent from the following description of exemplary, non-limiting embodiments which are given with reference to the drawings. [Brief explanation of the drawings]

[0011] [Figure 1] Plan view of the goods transfer facility [Figure 2] Front view of the unloading device and stacked goods [Figure 3] FIG. 1 is a front view schematically showing a suction device, an article detection device, and a stack of articles; [Figure 4] FIG. 10 is a side view schematically illustrating a suction device, an article detection device, and a stack of articles in a specific direction movement process. [Figure 5] FIG. 10 is a side view schematically showing the suction device in a state where the target article group is being sucked when the unloading operation is performed normally; [Figure 6] FIG. 10 is a side view schematically illustrating the suction device in a state where the group of target articles is suctioned and lifted up; [Figure 7] FIG. 10 is a side view schematically illustrating a suction device, an article detection device, and a stack of articles in a specific direction movement process. [Figure 8] FIG. 10 is a side view schematically showing a suction device, an article detection device, and a stack of articles during the initial specific direction movement process. [Figure 9] FIG. 10 is a side view showing an example of the position of the suction part in the up-down direction. [Figure 10] 10A and 10B are side views showing other examples of the positions of the suction parts in the up-down direction; [Figure 11] Control Block Diagram [Figure 12] Flowchart showing control by the control device [Figure 13] Flowchart showing control by the control device [Figure 14] Flowchart showing control by the control device [Figure 15] Plan view of an article transfer facility according to another embodiment DETAILED DESCRIPTION OF THE INVENTION

[0012] 1.Overview An example in which the unloading device 1 is applied to an article transfer facility will be described below with reference to the drawings. In this embodiment, as shown in FIG. 1, the article transfer facility includes the unloading device 1, a conveying device 6, and an automated warehouse (not shown). In this example, the unloading device 1 transfers multiple articles W that have been removed from the automated warehouse from a take-out area 7 to a destination area 8. The conveying device 6 conveys the multiple articles W that have been removed from the automated warehouse to the take-out area 7, and also carries the multiple articles W that are in the destination area 8 out of the automated warehouse.

[0013] In this example, as shown in FIGS. 1 and 2, the transport device 6 includes a first conveyor 6a and a second conveyor 6b. The first conveyor 6a transports multiple articles W from the automated warehouse to the take-out area 7. The first conveyor 6a also transports the remaining articles W that have not been transferred by the unloading device 1 from the take-out area 7 to the automated warehouse. The second conveyor 6b transports the multiple articles W that have been transferred from the take-out area 7 to the destination area 8 from the destination area 8 to outside the article transfer equipment. Note that the destination of the articles W transported by the second conveyor 6b may also be the automated warehouse.

[0014] Hereinafter, one side of the specific direction X along the horizontal direction will be referred to as the specific direction first side X1, the other side of the specific direction X as the specific direction second side X2, and the direction along the horizontal direction and perpendicular to the specific direction X as the specific width direction Y. In addition, in this embodiment, one side of the specific width direction Y will be referred to as the specific width direction first side Y1, and the other side of the specific width direction Y as the specific width direction second side Y2. In this specification, "along a certain direction" is used as a concept that includes not only cases where something is parallel to that direction, but also cases where something is inclined with respect to that direction (specifically, cases where something is slightly inclined with respect to that direction, such as cases where something is substantially parallel to that direction).

[0015] 1, the location where the placement unit 3 is arranged is the take-out area 7, the destination area 8 is set adjacent to one side of the take-out area 7 in the specific width direction Y, and the waiting area 9 is set adjacent to the take-out area 7 on the specific direction second side X2. In this example, the destination area 8 is adjacent to the take-out area 7 on the specific width direction second side Y2. In the illustrated example, the destination area 8 is arranged with a gap narrower than the dimension in the specific width direction Y of the suction device 2 (specifically, the suction support unit 22) described later. Furthermore, the destination area 8 and the take-out area 7 are arranged on the specific direction second side X2 with respect to the unloading device 1 (specifically, fixed parts such as the pedestal unit 41 described later), and the waiting area 9 is arranged on the specific direction second side X2 with respect to the take-out area 7 and the destination area 8.

[0016] In this embodiment, as shown in FIGS. 1 and 2, in the take-out area 7, a plurality of items W (hereinafter referred to as a stacked item group Wt) are stacked on a placement section 3. In this example, the placement section 3 is a pallet P. That is, the stacked item group Wt is placed on the pallet P. In this example, a pallet P is also placed as a placement section 3 in the destination area 8. The items W transferred from the take-out area 7 are stacked on the pallet P in the destination area 8. In the example of FIGS. 1 and 2, the take-out area 7 is set on the conveying surface of the first conveyor 6a. In addition, the destination area 8 is set on the conveying surface of the second conveyor 6b. The items W are containers with lids, and contain various items such as food, drinking water, machine parts, etc. In this embodiment, the multiple items W belonging to one stacked item group Wt are containers of the same shape and dimensions. In the illustrated example, the items W are cardboard boxes. The placement unit 3 is not limited to the pallet P, and may be, for example, a lifting platform of a lifter or a conveying surface of a conveyor. In other words, the article W does not necessarily have to be placed on the pallet P.

[0017] 2.Unloading equipment As shown in Figures 5 and 6, the unloading apparatus 1 separates a target group of items Ws, which are multiple items W belonging to the top tier, from a stacked group of items Wt, which are multiple items W stacked on the mounting section 3. In this embodiment, the unloading apparatus 1 lifts the target group of items Ws relative to the stacked group of items Wt below it in the removal area 7. This separates the target group of items Ws from the stacked group of items Wt below it. In this example, the unloading apparatus 1 separates all items W belonging to the target group of items Ws from the stacked group of items Wt below it. The specific configuration of the unloading apparatus 1 will be described below.

[0018] 1, 2, 3, and 11, the unloading apparatus 1 includes a suction device 2 having a suction unit 21 that suctions the upper surface 11 of the target item group Ws to hold the target item group Ws, a moving device 4 that moves the placement unit 3 and the suction unit 21 relatively in a specific direction X along the horizontal direction and in the up and down directions, and a control device 100 that controls the suction device 2 and the moving device 4. In this embodiment, the unloading apparatus 1 further includes a height detection device 10.

[0019] 2-1. Height detection device In this embodiment, as shown in FIGS. 1, 3, and 8, the height detection device 10 detects the initial height, which is the vertical dimension of the stacked article group Wt in an initial state before the target article group Ws has been separated. In this embodiment, the height detection device 10 is disposed midway along the transport path of the first conveyor 6a, and detects the height of the stacked article group Wt transported to the take-out area 7 by the first conveyor 6a. Therefore, what is detected by the height detection device 10 is the height of the initial state before the article W (target article group Ws) is separated from the stacked article group Wt. Information about the initial height, which indicates the height of the stacked article group Wt in its initial state, is output to the control device 100. As a result, the control device 100 acquires the information about the initial height from the height detection device 10 as control information 101. Based on the information about the initial height, the control device 100 moves the suction unit 21 to a position corresponding to the target article group Ws among the stacked article group Wt.

[0020] 2-2.Mobile device In this embodiment, as shown in FIGS. 1 and 2, the moving device 4 is configured to move the suction unit 21 in a specific direction X, a specific width direction Y, and in the vertical direction. This allows the moving device 4 to lift the suction unit 21, which has suction-held the target item group Ws, above the placement unit 3 and the stacked item group Wt below the target item group Ws. The moving device 4 can also move the suction unit 21 between the take-out area 7, the destination area 8, and the waiting area 9. In this example, as shown in FIGS. 1 and 2, the moving device 4 includes a base 41, a rotating unit 42, and a robot arm 46 (a first arm 43 and a second arm 44). The base 41 is fixed to a stand 39. The rotating unit 42 is supported on the base 41 so as to be rotatable about an axis extending in the vertical direction. The base end of the first arm 43 is swingably connected to the rotating unit 42. The base end of the second arm 44 is swingably connected to the tip end of the first arm 43. The suction device 2 is connected to the tip end of the second arm 44.

[0021] 2-3.Adsorption device 2 and 3, the suction device 2 includes a suction section 21, a suction support section 22, and a connecting section 23. In this embodiment, the suction support section 22 supports the suction section 21. In this embodiment, the suction support section 22 supports from above a plurality of suction sections 21 (suction pads) arranged in a plane. The connecting section 23 connects the suction support section 22 to the moving device 4. In the illustrated example, a base end of the connecting section 23 is swingably connected to a tip end of a second arm 44 of the moving device 4. A tip end of the connecting section 23 is fixed to an upward-facing surface of the suction support section 22. The suction section 21 and the suction support section 22 can be freely moved within a specified range (within the movable range of the robot arm 46 in the illustrated example) by rotation of the rotating section 42 of the moving device 4 and swing of the first arm 43, the second arm 44, and the connecting section 23. With this configuration, the unloading device 1 can transfer the target article group Ws held by the suction unit 21 from the take-out area 7 to the destination area 8.

[0022] In this embodiment, as shown in FIGS. 2, 3, and 4, a plurality of suction units 21 are supported by the suction support unit 22. More specifically, the plurality of suction units 21 are arranged in a plane along the downward surface of the suction support unit 22. In this embodiment, the suction units 21 are configured to be elastically deformable in the vertical direction. In this example, the suction units 21 are suction pads. That is, the suction units 21 are formed in a bellows shape that is expandable and contractible in the vertical direction. In this case, the lower surface of the suction pad serving as the suction unit 21 serves as the suction surface 21a that contacts the upper surface 11 of the target article group Ws. Therefore, in this example, the position of the suction surface 21a changes relative to the suction support unit 22 and the article detection device 5 depending on the deflection of the suction pad. Note that in this embodiment, the plurality of suction units 21 are arranged in a plane, and therefore the suction surface 21a is formed by the collective lower surfaces of the plurality of suction units 21. A valve (not shown) and a suction device (not shown), such as a pump, are connected to the suction unit 21 via tubes (not shown). The control device 100 controls the valve to switch the state of the suction unit 21 between a suction state in which the item W is suctioned and a suction-released state in which the item W is not suctioned. In this example, the multiple suction units 21 have the same structure. In this example, the suction unit 21 is fixed to the suction support unit 22 as described above and moves integrally with the suction support unit 22. However, the suction unit 21 may also be configured to move independently. In that case, for example, the suction device 2 may not include the suction support unit 22 and the connecting unit 23, and the suction unit 21 may be directly connected to the tip of the second arm 44.

[0023] 2-4.Item detection device As shown in FIGS. 3 and 4 , the unloading apparatus 1 further includes an article detection device 5. The article detection device 5 has an adsorption surface 21a, which is a surface of the adsorption unit 21 that contacts the upper surface 11 of the target article group Ws. The article detection device 5 is spaced a specific distance L below the adsorption surface 21a and detects an article W that crosses a detection line R that is set along the specific width direction Y at a position adjacent to the adsorption surface 21a on the specific direction first side X1. In this embodiment, the article detection device 5 is connected to the adsorption unit 21 so as to move integrally with the adsorption unit 21. Furthermore, the relative position of the article detection device 5 with respect to the adsorption support unit 22 is fixed. Therefore, if deflection of the adsorption unit 21 is not taken into consideration, the relative position of the article detection device 5 and the adsorption unit 21 is also fixed. Therefore, the article detection device 5 is connected to the adsorption unit 21 so as to move up and down integrally with the adsorption unit 21. In this example, the article detection device 5 is fixed to the end of the adsorption support unit 22 on the specific direction first side X1. The item detection device 5 is disposed at a position adjacent to the first side X1 in the specific direction with respect to the suction unit 21. In this example, the specific distance L is a distance based on the suction surface 21a when the suction unit 21 is not deflected. A specific description of the specific distance L will be given later.

[0024] In this example, as shown in FIG. 3 , the article detection device 5 is configured using a transmission-type optical sensor 50. Accordingly, the optical sensor 50 includes a light-emitting unit 51 and a light-receiving unit 52. The light-emitting unit 51 and the light-receiving unit 52 are separately arranged on both outer sides of the plurality of suction units 21 in the specific width direction Y. Furthermore, the light-emitting unit 51 and the light-receiving unit 52 are arranged to be spaced a specific distance L below the suction surface 21a and to form a detection line R along the specific width direction Y. Note that, although the article detection device 5 is configured using the transmission-type optical sensor 50 in this example, a reflective optical sensor 50 in which the light-emitting unit and the light-receiving unit are integrated may be provided on one side of the specific direction X, and a reflector may be provided on the other side of the specific direction X. Furthermore, 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, for example.

[0025] 2-5.Control device In this embodiment, as shown in Fig. 11, the control device 100 is configured to execute arithmetic processing and various controls described below. The control device 100 includes an arithmetic processing device such as a CPU and peripheral circuits such as a memory, and each function of the control device 100 is realized by cooperation between this hardware and programs executed on the hardware such as the arithmetic processing device. The control device 100 controls the suction device 2, the movement device 4, the item detection device 5, and the height detection device 10. In this example, the control device 100 acquires control information 101 from each of the suction device 2, the movement device 4, the item detection device 5, the height detection device 10, and the management system 110. Note that this control information 101 may be configured to be acquired from a controller higher in level than the control device 100.

[0026] In this embodiment, the control device 100 performs a first separation operation, i.e., a first transfer processing (Figs. 8, 12, 13) which is an operation of separating the target item group Ws from the stacked item group Wt in an initial state where separation of the target item group Ws has never been performed, and transferring it to the transfer destination area 8. The control device 100 also performs a second or subsequent separation operation, i.e., a second transfer processing (Figs. 4 to 7, 12, 14) which is an operation of separating the target item group Ws from the second or subsequent tiers from the top based on the stacked item group Wt in the initial state, and transferring it to the transfer destination area 8. Below, the second transfer processing will first be described in detail.

[0027] 2-5-1. Second transfer process As shown in FIG. 11 , the control device 100 acquires control information 101 for calculating the vertical relative distance M, which is the relative distance in the vertical direction between the upper surface 11 of the target article group Ws and the suction surface 21a, where the vertical dimension of the articles W constituting the target article group Ws is defined as the article height H. The control device 100 acquires the control information 101 from each of the suction device 2, the moving device 4, the article detection device 5, and the height detection device 10. In this embodiment, the control device 100 acquires, as the control information 101, suction surface position information indicating the vertical position of the suction surface 21a of the suction unit 21 from the moving device 4. This suction surface position information is calculated from the position of the tip of the second arm 44, which serves as control information for the moving device 4, and the distance (constant) from the tip to the suction surface 21a. The control device 100 also acquires detection information from the article detection device 5, specifically, information on whether the optical sensor 50 has detected an article W, as the control information 101. In this embodiment, the control information 101 includes information on the initial height detected by the height detection device 10, information on the initial number of layers, which is the number of layers of the stacked item group Wt in the initial state, and information on the number of separated layers, which is the number of layers of the target item group Ws that have already been separated from the same stacked item group Wt. In this example, as described above, the control device 100 acquires the information on the initial height from the height detection device 10 as the control information 101. The control device 100 also acquires, as the control information 101, layer number information indicating the number of layers of the stacked item group Wt in the take-out area 7 from the management system 110, which manages information on multiple stacked item groups Wt in the item transfer equipment. The information on the initial number of layers is included in this layer number information. The separated number of layers is the number of layers of the target item group Ws that have already been separated from the stacked item group Wt in the initial state by the unloading device 1. The information on the separated number of layers is acquired from the operation history of the unloading device 1 provided in the control device 100.

[0028] 3, 4, and 7, the control device 100 calculates the vertical relative distance M by dividing the initial state height by the initial number of tiers as the item height H, multiplying the item height H by the number of separated tiers as the separated height, and subtracting the separated height from the initial state height as the vertical dimension of the current stacked article group Wt. In this example, the control device 100 also calculates the vertical relative distance M using information on the relative position of the placement unit 3 and the suction unit 21 determined by the moving device 4. Specifically, the control device 100 obtains the vertical distance between the upper surface of the placement unit 3 and the suction surface 21a from the suction surface position information, and calculates the vertical relative distance M by subtracting the vertical dimension of the current stacked article group Wt calculated as above from this distance. Calculating the vertical relative distance M in this manner makes it possible to eliminate the need for a sensor or the like for constantly detecting the vertical dimension of the stacked article group Wt on the placement unit 3.

[0029] 4, the control device 100 executes a specific direction movement process in which the moving device 4 operates to move the suction unit 21 toward the specific direction first side X1 relative to the mounting unit 3 from a state in which the vertical relative distance M based on the control information 101 is greater than the greater of the item height H and the specific distance L and is smaller than the length obtained by adding the item height H to the specific distance L, and the detection line R is located on the specific direction second side X2 with respect to the target item group Ws, until the detection line R is located on the specific direction first side X1 with respect to the target item group Ws. Then, as shown in FIGS. 7 and 14, if the item detection device 5 detects an item W during the execution of the specific direction movement process, the control device 100 prohibits the operation of the moving device 4 to move the suction unit 21 closer to the target item group Ws in the vertical direction.

[0030] In this embodiment, as shown in FIG. 4, the specific direction movement process is executed when the vertical relative distance M based on the control information 101 is greater than the larger of the item height H and the specific distance L plus the margin distance B, and is smaller than the value obtained by subtracting the margin distance B from the length obtained by adding the specific distance L to the item height H. The margin distance B is preferably set to be greater than or equal to the maximum error in the vertical relative position between the placement unit 3 and the suction surface 21a determined by the moving device 4 (in other words, the vertical position error of the suction surface 21a determined by the moving device 4). In this embodiment, the height detection device 10 detects the vertical dimension of the stacked item group Wt in the initial state. Therefore, for example, the margin distance B can be set to a value equivalent to the sum of the maximum error in the vertical relative position between the placement unit 3 and the suction surface 21a determined by the moving device 4 and the maximum detection error in the vertical dimension of the stacked item group Wt determined by the height detection device 10.

[0031] The example of FIG. 9 shows a state in which the vertical relative distance M is greater than the item height H and the specific distance L, and smaller than the sum of the item height H and the specific distance L. Here, if an item W (hereinafter, "abnormal item Wa" (indicated by the two-dot chain line in FIG. 9)) that should not be present on the target item group Ws is present, the distance between the upper surface of the abnormal item Wa and the suction surface 21a is set to the tentative item relative distance M'. The example of FIG. 9 assumes that there is no error in the vertical relative position between the placement unit 3 and the suction surface 21a caused by the moving device 4. However, if the vertical position of the suction surface 21a is lower by the amount of error than the position in the absence of error, and if the tentative item relative distance M' in the figure is smaller than the error, the abnormal item Wa will interfere with the suction unit 21 during execution of the specific direction movement process. Therefore, in order to prevent interference between the abnormal item Wa and the suction section 21 even when the above error becomes maximum, the margin distance B is set to be equal to or greater than the maximum value of the error in the vertical relative position between the loading section 3 and the suction surface 21a by the moving device 4, and the specific direction movement process is executed when the vertical relative distance M is greater than the value obtained by adding the margin distance B to the larger of the item height H and the specific distance L.

[0032] The example in Fig. 10 shows a state in which the vertical relative distance M is equal to the value obtained by adding the specific distance L to the item height H. In other words, the vertical positions of the top surface of the abnormal item Wa (indicated by the two-dot chain line in Fig. 10) and the detection line R of the item detection device 5 are the same. Fig. 10 assumes that there is no error in the relative vertical position between the placement unit 3 and the suction surface 21a caused by the moving device 4. However, if the vertical position of the detection line R in the figure becomes higher by the amount of error than the position in the absence of error, the position of the detection line R will be higher than the position of the top surface of the abnormal item Wa, and the detection line R will not intersect with the abnormal item Wa during the specific direction movement process. Therefore, to prevent the abnormal object Wa from failing to intersect with the detection line R even when the error is at its maximum, the margin distance B is set to be equal to or greater than the maximum value of the error in the vertical relative position between the mounting unit 3 and the suction surface 21a caused by the moving device 4, and the specific direction movement process is executed when the vertical relative distance M is smaller than the value obtained by subtracting the margin distance B from the length obtained by adding the specific distance L to the object height H. In this way, the control device 100 executes the specific direction movement process when the vertical relative distance M is within a range set in consideration of the margin distance B, so that when an abnormal object Wa is present, it is possible to prevent the abnormal object Wa from interfering with the suction unit 21 or failing to intersect with the detection line R.

[0033] 4, 9, and 10, in this embodiment, the specific distance L is set to be equal to or greater than the maximum error in the vertical relative position between the mounting unit 3 and the suction surface 21 as determined by the moving device 4, but equal to or less than the article height H. In this example, the specific distance L is set to be equal to or greater than the margin distance B but equal to or less than the article height H. The margin distance B can be set as described above, and for example, the margin distance B can be set to a value equivalent to the sum of the maximum error in the vertical relative position between the mounting unit 3 and the suction surface 21a as determined by the moving device 4 and the maximum detection error in the vertical dimension of the stacked article group Wt as determined by the height detection device 10. In this case, the specific distance L is set to be equal to or greater than the sum of the maximum error in the vertical relative position between the mounting unit 3 and the suction surface 21a as determined by the moving device 4 and the maximum detection error in the vertical dimension of the stacked article group Wt as determined by the height detection device 10, but equal to or less than the article height H. If the specific distance L is less than the margin distance B and the vertical position of the suction surface 21a is lower by the margin distance B than the position when there is no error in the vertical relative position between the placement unit 3 and the suction surface 21a caused by the moving device 4, there is a risk that the abnormal item Wa will interfere with the suction unit 21 during the specific direction movement process. Furthermore, if the specific distance L is greater than the item height H, depending on the vertical position of the suction surface 21a, there is a risk that the detection line R will not intersect with the abnormal item Wa but will intersect with the stacked item group Wt below the abnormal item Wa. In contrast, in this embodiment, the specific distance L is set as described above. This avoids the risk of interference between the abnormal item Wa and the suction unit 21 and the risk of the detection line R intersecting with normal items W below the abnormal item Wa. After the specific direction movement process is completed, the distance by which the suction unit 21 is lowered to suction the target item group Ws can be minimized, making it easier to shorten the time cycle of the unloading operation. In the illustrated example, the specific distance L is set to half the item height H plus the margin distance B. When there are multiple types of items W with different vertical dimensions, it is preferable to set the item height H to the height of the item W with the smallest vertical dimension.

[0034] 4 and 7, before the specific direction movement process is executed, the suction unit 21 is positioned at a standby position P0 in the standby area 9. For example, the standby position P0 is set to the same position as a second reference position P2 (described later) when the stacked article group Wt with the largest vertical dimension is placed on the placement unit 3.

[0035] The control device 100 performs calculation processing of the vertical relative distance M based on the control information 101, and controls the moving device 4 to move (lower in the examples of Figures 4 and 7) the suction unit 21 from the waiting position P0 in the waiting area 9 to the second reference position P2. Here, the second reference position P2 is a position in the waiting area 9 whose vertical position changes depending on the vertical dimension of the stacked item group Wt, and the second reference position P2 is a position where the position of the suction surface 21a is higher by the vertical relative distance M than the top surface 11 of the target item group Ws on the topmost level of the stacked item group Wt.

[0036] Then, the control device 100 controls the movement device 4 to horizontally move the suction unit 21 from the second specific direction side X2 to the first specific direction side X1 relative to the placement unit 3 and the stacked item group Wt while maintaining the vertical relative distance M. As a result, the item detection device 5 moves from a state in which it is located on the second specific direction side X2 relative to the target item group Ws in the waiting area 9 to the first specific direction side X1 relative to the target item group Ws. That is, in this embodiment, the control device 100 executes the specific direction movement process by moving the suction unit 21 from the second specific direction side X2 to the first specific direction side X1. During and after the specific direction movement process is completed, the multiple suction units 21, the placement unit 3, and the stacked item group Wt overlap in the vertical direction.

[0037] In this embodiment, as shown in FIG. 7 , if the detection line R intersects with an item W (an abnormal item Wa) located above the target item group Ws during the specific direction movement process, i.e., if the item detection device 5 detects an item W, the control device 100 controls the movement device 4 after the specific direction movement process is completed so that the suction unit 21 does not move toward (lower) the target item group Ws. In this example, if the control device 100 prohibits the descent of the suction unit 21 in this way, it assumes that the unloading operation has become abnormal and issues an abnormality notification. The abnormality notification is performed, for example, by outputting an abnormality alarm sound from a speaker or buzzer, turning on an abnormality indicator light, or notifying a user-operated terminal of the abnormality information. Because of this configuration, even if some items W belonging to the target item group Ws remain without being separated from the stacked item group Wt on the lower tier, the remaining items W can be detected during the next unloading operation and the descent of the suction unit 21 can be stopped. This prevents a collision between the suction unit 21 and the abnormal item Wa. Furthermore, even if there is an error in the control information 101, such a situation can be avoided. For example, if the initial number of layers is "M layers" and the number of layers separated by the unloading device 1 is correctly "N layers," but the control device 100 recognizes this as "N+1 layers," the control device 100 will recognize the number of layers of the stacked article group Wt as "MN-1 layers," which is less than the actual "MN layers." Even in such a case, the control device 100 can detect the "MN layer" (top layer) of article W during the unloading operation and stop the descent of the suction unit 21. Note that possible causes of the number of separated layers recognized by the control device 100 being an incorrect value include, for example, recovery processing after an abnormal event such as a power outage.

[0038] On the other hand, in this embodiment, as shown in Figure 5, if the item detection device 5 does not detect an item W during the specific direction movement process, the control device 100 operates the moving device 4 after the specific direction movement process to move the suction unit 21 closer to the target item group Ws in the vertical direction. Then, the control device 100 stops the moving device 4 after the suction surface 21a contacts the upper surface 11 of the target item group Ws, causes the suction unit 21 to suction the upper surface 11 of the target item group Ws, and then operates the moving device 4 to increase the distance between the upper surface of the mounting unit 3 and the suction surface 21a, thereby separating the target item group Ws from the stacked item group Wt. In this example, if the item detection device 5 does not detect an item W even after the specific direction movement process is performed, the control device 100 controls the moving device 4 to lower the multiple suction units 21 toward the target item group Ws. The control device 100 then controls the moving device 4 to stop the descent of the suction units 21 after the suction surfaces 21a of each of the multiple suction units 21 come into contact with the upper surfaces 11 of the articles W constituting the target article group Ws. The control device 100 then controls the suction device 2 so that the multiple suction units 21 change from the suction-released state to the suctioned state. The control device 100 then controls the suction device 2 and the moving device 4 to raise the suction units 21, while they are suction-holding the target article group Ws, relative to the stacked article group Wt below the target article group Ws. This separates the target article group Ws from the stacked article group Wt below it and lifts it relative to the placement unit 3 and the stacked article group Wt. In the example of FIG. 4, since no article W is present above the target article group Ws, the article detection device 5 does not detect the article W. In this case, the control device 100 lowers the suction units 21. When the suction surface 21a comes into contact with the upper surface 11 of the target article group Ws, the control device 100 gradually reduces the descending speed of the suction unit 21 to zero. After that, when the suction unit 21 has adsorbed the target article group Ws, the moving device 4 lifts the target article group Ws relative to the stacked article group Wt below it and separates it (see FIG. 6).In the example of Figure 7, after performing this operation, some of the items W of the target item group Ws are not separated and remain on top of the stacked item group Wt.In such a case, the item W is detected by the specific direction movement process executed before the next separation operation, so the suction section 21 stops without descending, and the next separation operation is not performed.

[0039] As shown in FIGS. 1 and 2 , in this embodiment, the control device 100 separates the target group of items Ws from the stacked group of items Wt on the placement unit 3 arranged in the take-out area 7, and then performs a transfer process in which the suction unit 21 and the moving device 4 are operated to move the separated target group of items Ws to the destination area 8 and place it in the destination area 8. In this example, the control device 100 controls the suction unit 2 and the moving device 4 to move the separated target group of items Ws and the suction unit 21 that adsorbs and holds it from the take-out area 7 to the destination area 8. Specifically, the control device 100 controls the moving device 4 to place the adsorbed and held target group of items Ws on a pallet P in the destination area 8, or on top of a stacked group of items Wt if the pallet P already has the stacked group of items Wt placed on it. Thereafter, the control device 100 controls the suction device 2 to change the suction unit 21 from the adsorption state to the adsorption release state. As a result, the target article group Ws separated from the stacked article group Wt arranged in the take-out area 7 is transferred from the take-out area 7 to the transfer destination area 8.

[0040] Thereafter, the control device 100 operates the moving device 4 to move the suction unit 21 to the waiting area 9 before starting the next specific direction movement process. In this example, the control device 100 controls the moving device 4 to move the suction unit 21, after transferring the target item group Ws to the destination area 8, to a waiting position P0 in the waiting area 9 adjacent to the specific direction second side X2 with respect to the take-out area 7. In this way, because the waiting area 9 is adjacent to the specific direction second side X2 with respect to the take-out area 7, even if the height of the multiple layers of target item groups Ws (stacked item groups Wt) stacked in the destination area 8 by the transfer process becomes higher than the height of the stacked item groups Wt in the take-out area 7, the suction surface 21a of the suction unit 21 can be set to an appropriate height with respect to the upper surface 11 of the target item group Ws, and the specific direction movement process can be performed. In addition, the control device 100 may move the suction unit 21 after transferring the target item group Ws to the destination area 8 directly to the second reference position P2 instead of the standby position P0 in the standby area 9.

[0041] 2-5-2. First transfer procedure Next, the first transfer process will be described. Here, a description of the configuration common to the second transfer process will be omitted. In this embodiment, as shown in FIG. 8, when separating the first target item group Ws from the initial stacked item group Wt, the control device 100 acquires control information 101 including the initial state height detected by the height detection device 10. Then, the control device 100 executes an initial specific direction movement process in which the moving device 4 is operated to move the suction unit 21 toward the specific direction first side X1 relative to the placement unit 3 from a state in which the vertical relative distance M based on the control information 101 is greater than zero and less than the specific distance L and the detection line R is located on the specific direction second side X2 relative to the target item group Ws until the detection line R is located on the specific direction first side X1 relative to the target item group Ws. In this example, the control device 100 controls the moving device 4 to move the suction unit 21 from the standby position P0 in the standby area 9 to the first reference position P1 (downward in the example of FIG. 8). The first reference position P1 is a position in the waiting area 9 whose vertical position changes depending on the initial state height detected by the height detection device 10, and is a position where the position of the suction surface 21a is higher by a vertical relative distance M than the upper surface 11 of the target item group Ws. The initial specific direction movement process is executed in a state where the vertical relative distance M is shorter than when the specific direction movement process is executed. Specifically, the initial specific direction movement process is executed in a state where the vertical relative distance M based on the control information 101 is greater than zero and smaller than the specific distance L. Therefore, the detection line R of the item detection device 5 overlaps with the target item group Ws when viewed from the specific width direction Y during the initial specific direction movement process. In this example, as shown in FIG. 8, the initial specific direction movement process is executed in a state where the vertical relative distance M based on the control information 101 is greater than the margin distance B and smaller than the value obtained by subtracting the margin distance B from the specific distance L. This makes it possible to avoid a situation in which the target item group Ws and the suction unit 21 collide during the execution of the initial specific direction movement process, even if the position of the suction surface 21a is shifted downward by the maximum value of the error in the vertical relative position between the loading unit 3 and the suction surface 21a caused by the moving device 4.Furthermore, even if the position of the suction surface 21a is shifted upward by the maximum value of the error in the vertical relative position between the placement unit 3 and the suction surface 21a caused by the moving device 4, it is possible to avoid a situation in which the target article group Ws and the detection line R do not intersect during execution of the initial specific direction movement process. In this embodiment, if there is an area in which the detection line R does not intersect with the article W during execution of the initial specific direction movement process, the control device 100 recognizes that no article W is present in part of the top shelf of the stacked article group Wt. In this example, because the detection line R is formed along the specific direction X, the control device 100 can recognize that there is an area in the top shelf of the stacked article group Wt in which one or more rows of articles W are not placed along the specific direction X.

[0042] In this embodiment, as shown in Figures 8 and 13, if there is an area where the item detection device 5 does not detect the item W during the execution of the initial specific direction movement process, the operation of the moving device 4, which moves the suction unit 21 closer to the target item group Ws in the vertical direction, is prohibited. Specifically, after executing the initial specific direction movement process, the control device 100 controls the moving device 4 so that the suction unit 21 does not move closer to (here, lower) the target item group Ws. In this way, when the control device 100 prohibits the descent of the suction unit 21, it assumes that an abnormality has occurred in the unloading operation and issues an abnormality notification. The abnormality notification is carried out, for example, by outputting an abnormality notification sound from a speaker or buzzer, turning on an abnormality indicator light, notifying an abnormality information to a terminal operated by a user, etc.

[0043] 3. Unloading method The unloading method in this embodiment will be described below based on the flowcharts shown in Figures 12, 13, and 14. In this example, the unloading device 1 separates the target item group Ws from the stacked item group Wt in the take-out area 7 and transfers the target item group Ws to the transfer destination area 8.

[0044] The control device 100 determines whether the stacked group of articles Wt in the take-out area 7 is in an initial state, i.e., whether the stacked group of articles Wt has never been separated from the target group of articles Ws (S01). If the control device 100 determines that the stacked group of articles Wt is in an initial state (S01: Yes), it executes a first transfer process (S02). On the other hand, if the control device 100 determines that the stacked group of articles Wt is not in an initial state (S02: No), it executes a second transfer process (S03).

[0045] When executing the first transfer process, the control device 100 acquires control information 101 from the suction device 2, the moving device 4, the item detection device 5, the height detection device 10, and the management system 110 (S11). Then, the control device 100 moves the suction unit 21 to a first reference position P1 based on the control information 101 (S12). Thereafter, the control device 100 executes an initial specific direction movement process to slide the suction unit 21 from the first specific direction side X1 to the second specific direction side X2 relative to the placement unit 3 (stacked item group Wt) at the height of the first reference position P1 (S13). The control device 100 determines whether there is an area where the item detection device 5 does not detect the item W on the top layer of the stacked item group Wt during the execution of the initial specific direction movement process (S14). If the control device 100 determines that there is an area where the item W is not detected (S14: Yes), it prohibits the suction unit 21 from descending (S21). For example, in the state shown in Figure 8, there is an area in some columns of the top shelf where no articles W are detected, so the suction unit 21 is not lowered. On the other hand, if the control device 100 determines that there is no area in the top shelf where no articles W are detected (S14: No), that is, if all of the articles W are placed as the target article group Ws on the top shelf of the stacked article group Wt, it controls the moving device 4 to lower the suction unit 21 (S15). Then, when the suction unit 21 contacts the upper surface 11 of the target article group Ws, the control device 100 stops the descent of the suction unit 21 and switches the suction unit 21 from the suction release state to the suction state to suction the target article group Ws (S16). Thereafter, the control device 100 raises the suction unit 21 to separate the target article group Ws from the stacked article group Wt below it (S17). The control device 100 moves the suction unit 21, which is holding the target item group Ws by suction, from the take-out area 7 onto the pallet P in the transfer destination area 8, or onto the stacked item group Wt if it is placed on the pallet P (S18).Then, the control device 100 switches the suction unit 21 from the suction state to the suction release state (S19), and moves the suction unit 21 to the standby position P0 in the standby area 9 (S20).

[0046] When executing the second transfer process, the control device 100 acquires control information 101 from the suction device 2, the moving device 4, the item detection device 5, the height detection device 10, and the management system 110 (S31). Then, the control device 100 moves the suction unit 21 to the second reference position P2 based on the control information 101 (S32). Thereafter, the control device 100 executes a specific direction movement process to slide the suction unit 21 from the first specific direction side X1 to the second specific direction side X2 relative to the placement unit 3 (the stacked item group Wt) at the height of the second reference position P2 (S33). The control device 100 determines whether the item detection device 5 has detected an item W during the execution of the specific direction movement process (S34). If the control device 100 determines that the item detection device 5 has detected an item W (S34: Yes), the control device 100 prohibits the suction unit 21 from descending (S41). In the example shown in FIG. 7, the item detection device 5 detects an item W remaining on the target item group Ws, so the suction unit 21 is not lowered. When the control device 100 determines that the item detection device 5 does not detect an item W (S34: No), it controls the moving device 4 to lower the suction unit 21 (S35). For example, the suction unit 21 is gradually lowered from the state shown in FIG. 4. Then, after the suction unit 21 contacts the upper surface 11 of the target item group Ws, the control device 100 stops the descent of the suction unit 21 and switches the suction unit 21 from the suction release state to the suction state, causing the suction unit 21 to suction the target item group Ws (S36). The example in FIG. 5 shows a state in which the suction unit 21 is lowered and suctioning the target item group Ws. Thereafter, the control device 100 raises the suction unit 21, which is holding the target item group Ws, to separate the target item group Ws from the stacked item group Wt below it (S37). Figure 6 shows a state in which the target group of items Ws that was picked up in Figure 5 is lifted up relative to the stacked group of items Wt below it, i.e., a separated state. The control device 100 moves the suction unit 21, which has picked up the target group of items Ws, from the take-out area 7 onto the pallet P in the transfer destination area 8, or onto the stacked group of items Wt if it is placed on the pallet P (S38). Thereafter, the control device 100 switches the suction unit 21 from the suction state to the suction release state (S39), and moves the suction unit 21 to the standby position P0 in the standby area 9 (S40).

[0047] 4. Other embodiments Next, other embodiments of the unloading device will be described.

[0048] (1) In the above embodiment, the adsorption unit 21 is described as being configured to be expandable and contractible in the vertical direction, such as a suction pad. However, the present invention is not limited to such a configuration, and the adsorption unit 21 may be configured to not deform in the vertical direction. For example, the adsorption unit 21 may not be bellows-shaped, but may be an adsorption pad whose adsorption surface 21a does not bend. Furthermore, for example, if the article W has a portion made of a magnetic material such as iron, the adsorption unit 21 may be configured to attract the article W by magnetic force. In this case, it is preferable that the adsorption unit 21 be configured to include a permanent magnet or an electromagnet.

[0049] (2) In the above embodiment, the control device 100 has been described as an example of a configuration in which the placement unit 3 (stacked article group Wt) is fixed in a horizontal position, and the suction unit 21 is moved from the second specific direction side X2 to the first specific direction side X1 relative to the placement unit 3 (stacked article group Wt). However, the present invention is not limited to such a configuration, and, for example, the placement unit 3 (stacked article group Wt) may be moved from the second specific direction side X2 to the first specific direction side X1 relative to the suction unit 21 while the horizontal position of the suction unit 21 is fixed.

[0050] (3) In the above embodiment, the control device 100 has been described as an example of a configuration in which the placement unit 3 (stacked article group Wt) is fixed in its vertical position while the suction unit 21 is lowered, thereby bringing the placement unit 3 and the suction unit 21 relatively closer to each other. However, the present invention is not limited to such a configuration, and for example, the placement unit 3 (stacked article group Wt) may be raised while the vertical position of the suction unit 21 is fixed, thereby bringing the placement unit 3 and the suction unit 21 relatively closer to each other. In this case, for example, a lifter may be installed in the take-out area 7, and the pallet P as the placement unit 3 and the stacked article group Wt may be placed on the lifter, and these may be raised and lowered.

[0051] (4) In the above embodiment, a configuration has been described in which the specific distance L is set to be equal to or greater than the maximum error in the relative position between the mounting unit 3 and the suction unit 21 in the vertical direction caused by the moving device 4, but equal to or less than the article height H. However, the present invention is not limited to such a configuration, and the specific distance L may be set to be greater than the article height H. Furthermore, if the error in the relative position between the mounting unit 3 and the suction unit 21 in the vertical direction caused by the moving device 4 is small enough to be negligible, the specific distance L may be set without taking such an error into consideration.

[0052] (5) In the above embodiment, the moving device 4 includes the robot arm 46 (first arm 43, second arm 44, and third arm 45), and is configured to move the suction unit 21 in the specific direction X, the specific width direction Y, and the up-down direction. However, the moving device 4 is not limited to such a configuration, and may be configured using a three-axis robot equipped with a movement mechanism that moves the suction unit 21 in each of the three directions of the specific direction X, the specific width direction Y, and the up-down direction.

[0053] (6) In the above embodiment, the destination area 8 is set adjacent to one side of the take-out area 7 in the specific width direction Y, and the standby area 9 is set adjacent to the take-out area 7 on the specific direction second side X2. However, the present invention is not limited to such a configuration. For example, as shown in FIG. 15 , the destination area 8 may be set on the specific direction second side X2 of the take-out area 7, and the standby area 9 may be set between the take-out area 7 and the destination area 8 in the specific direction X. Note that in the example shown in FIG. 15 , unlike the example shown in FIG. 1 , the specific direction X is the left-right direction in the figure. In this case, the destination area 8 is set on the specific direction second side X2 of the take-out area 7 with a distance equal to or greater than the dimension of the suction device 2 (specifically, the suction support section 22) in the specific direction X, so that the standby area 9 can be appropriately set between the take-out area 7 and the destination area 8 in the specific direction X.

[0054] (7) In the above embodiment, the control device 100 has been described as an example of a configuration in which it performs an initial specific direction movement process when separating the first target item group Ws from the initial stacked item group Wt. However, the present invention is not limited to such a configuration, and the movement device 4 does not need to perform the initial specific direction movement process on the initial stacked item group Wt. In this case, for example, even if there is an area on the top level of the initial stacked item group Wt where no items W exist, the suction unit 21 may be configured to pick up all items W present on the top level and transfer these items W to an area other than the transfer destination area 8.

[0055] (8) In the above embodiment, the control device 100 is described as being configured to calculate the vertical relative distance M by dividing the initial state height by the initial number of tiers as the item height H, multiplying the item height H by the number of separated tiers as the separated height, and subtracting the separated height from the initial state height as the vertical dimension of the currently stacked group of items Wt. However, this configuration is not limited to this. For example, a distance measurement sensor may be provided in the suction device 2 to measure the vertical relative distance M.

[0056] (9) The configurations disclosed in the above-described embodiments (including the above-described embodiments and other embodiments; the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction occurs. Regarding other configurations, the embodiments disclosed in this specification are illustrative in all respects and can be appropriately modified within the scope of the present disclosure.

[0057] 5. Overview of the above embodiment The unloading device described above will now be outlined.

[0058] The unloading device according to the present disclosure is an unloading device that separates a group of target articles, which are a plurality of articles belonging to the top layer, from a group of stacked articles, which are a plurality of articles stacked on a loading section, and a suction device having a suction section that suctions the upper surface of the target item group to hold the target item group; a moving device that moves the placement section and the suction section relatively in a specific direction along the horizontal direction and in an up-down direction; and a control device that controls the suction device and the moving device, one side of the specific direction is a specific direction first side, the other side of the specific direction is a specific direction second side, the direction along the horizontal direction and perpendicular to the specific direction is a specific width direction, the vertical dimension of the articles constituting the target article group is an article height, and the surface of the suction section that contacts the upper surface of the target article group is a suction surface, an article detection device that is spaced a specific distance below the suction surface and detects the article that crosses a detection line that is set along the specific width direction at a position adjacent to the suction surface on the first side in the specific direction, The control device acquires control information for calculating a vertical relative distance, which is the relative distance in the vertical direction between the upper surface of the target item group and the suction surface, and executes a specific direction movement process in which the movement device is operated to move the suction unit toward the specific direction first side relative to the placement unit from a state in which the vertical relative distance based on the control information is greater than the greater of the item height and the specific distance and is smaller than the length of the item height plus the specific distance, and the detection line is located on the specific direction second side relative to the target item group, until the detection line is located on the specific direction first side relative to the target item group; If the object detection device detects the object during the execution of the specific direction movement process, the operation of the movement device that moves the suction unit closer to the group of target objects in the vertical direction is prohibited.

[0059] According to this configuration, the detection line is moved in a specific direction along the top surface of the target item group while maintaining the vertical relative distance greater than the greater of the item height and the specific distance, and smaller than the length obtained by adding the specific distance to the item height, thereby enabling the presence or absence of items present above the top surface of the target item group to be properly detected. When such an object is detected, i.e., when an object is present in a position where no object should be present, the movement device is prohibited from moving the suction unit closer to the group of target objects in the vertical direction, thereby reducing the possibility of the suction unit colliding with the object and damaging at least one of the suction unit and the object. In this manner, with this configuration, the item on the top shelf can be properly detected and reflected in the unloading operation.

[0060] Here, if the item detection device does not detect the item during the specific direction movement process, the control device preferably operates the moving device after the specific direction movement process to move the suction section closer to the target item group in the vertical direction, stops the moving device after the suction surface comes into contact with the upper surface of the target item group, causes the suction section to suction the upper surface of the target item group, and then operates the moving device to increase the distance between the upper surface of the placement section and the suction surface, thereby separating the target item group from the stacked item group.

[0061] According to this configuration, if there are no items remaining on the top shelf of the stacked items and the control information is correct, the target item group can be properly separated from the items stacked below it.

[0062] Preferably, the specific distance is set to be greater than the maximum error in the relative position between the placement unit and the suction unit in the vertical direction by the movement device, and equal to or less than the height of the article.

[0063] According to this configuration, by setting the specific distance to be greater than the maximum value of the error in the relative position between the placement section and the suction section in the vertical direction, even if the error becomes maximum, it is easy to avoid interference between the suction section and items located above the top surface of the target item group during execution of the specific direction movement process. Furthermore, by setting the specific distance to be less than the height of the items, it is easy to keep the moving distance for bringing the suction section closer to adsorb the target group of items after the specific direction movement process is completed short, making it easy to avoid a long time cycle in the unloading operation.

[0064] The moving device is configured to move the suction unit in the specific direction, the specific width direction, and the up-down direction, the object detection device is connected to the suction unit so as to move integrally therewith, A place where the placement unit is arranged is set as a take-out area, a transfer destination area is set at a place adjacent to the take-out area on one side in the specific width direction, and a waiting area is set at a place adjacent to the take-out area on a second side in the specific direction, The control device separates the target group of items from the stacked group of items on the storage unit placed in the removal area, then performs a transfer process in which the suction unit and the moving device are operated to move the separated target group of items to the destination area and place them in the destination area, and then operates the moving device to move the suction unit to the waiting area before starting the next specific direction movement process.

[0065] According to this configuration, the group of target items adsorbed by the suction unit is moved to the destination area by the moving device, and the suction by the suction unit is released, thereby allowing the transfer process to be properly performed in which the group of target items is separated one layer at a time from the group of stacked items that are stacked in multiple layers and transferred to the destination area. After the transfer process is completed, the suction unit is moved to the standby area, so that the next specific direction movement process can be started quickly. Furthermore, with this configuration, since the waiting area is set on the second specific direction side of the take-out area, it is easy to set the distance between the take-out area and the destination area small, which makes it easy to reduce the space required for unloading and shortens the time required for the suction unit to move from the take-out area to the destination area, making it easy to keep the cycle time of the unloading operation short. Furthermore, according to this configuration, since the waiting area is set on the second side in a specific direction relative to the removal area, even if the distance between the removal area and the destination area is set small and the height of the multiple-tiered group of target items stacked in the destination area due to the transfer process becomes higher than the height of the stacked group of items in the removal area, the destination area can be used to adjust the suction surface of the suction unit to an appropriate height relative to the top surface of the group of target items while avoiding interference between the suction unit and the multiple-tiered group of target items in the destination area, thereby performing the specific direction movement process.

[0066] The stacked article group may further include a height detection device for detecting an initial state height, which is a vertical dimension of the stacked article group in an initial state before separation of the target article group has been performed even once, The control device When separating the first group of target items from the group of stacked items in the initial state, the control information including the initial state height detected by the height detection device is acquired, and an initial specific direction movement process is performed in which the control information is obtained so that the vertical relative distance based on the control information is greater than zero and less than the specific distance, and the detection line is positioned on the second side of the target group of items in the specific direction, and the movement device is operated to move the suction unit toward the first side of the specific direction relative to the placement unit, until the detection line is positioned on the first side of the target group of items in the specific direction, If there is an area in which the item detection device does not detect the item during execution of the initial specific direction movement process, it is preferable to prohibit the operation of the movement device that moves the suction section closer to the group of target items in the vertical direction.

[0067] According to this configuration, if there is a shortage of items in the target item group at the top of the initially stacked item group, i.e., if the item is not in the position where it should be, it is possible to properly detect this and prohibit the operation of the moving device that moves the suction unit closer to the target item group in the vertical direction. Therefore, it is possible to avoid an operation to separate the target item group when the item is not in the position where it should be.

[0068] The stacked article group may further include a height detection device for detecting an initial state height, which is a vertical dimension of the stacked article group in an initial state before separation of the target article group has been performed even once, The control information includes information on the initial state height detected by the height detection device, information on the initial number of layers which is the number of layers of the stacked goods group in the initial state, and information on the number of separated layers which is the number of layers of the target goods group which have already been separated from the same stacked goods group, It is preferable that the control device calculates the vertical relative distance by dividing the initial state height by the initial number of tiers as the item height, multiplying the item height by the number of separated tiers as the separated height, and subtracting the separated height from the initial state height as the vertical dimension of the current stacked group of items.

[0069] According to this configuration, the vertical dimensions of the stacked item group in the initial state are first detected, and then multiple tiers of target item groups can be separated sequentially without detecting the vertical dimensions of the stacked item group.

[0070] The unloading device according to the present disclosure may have at least one of the above-described effects. [Explanation of symbols]

[0071] 2: Adsorption device 3: Placement section 4: Mobile device 5: Item detection device 7: Removal area 8: Destination area 9: Waiting area 10: Height detection device 11:Top surface 21: Adsorption part 21a: Adsorption surface 46: Robot arm 100: Control device 101: Control information G: Initial height H: Item height L: Specific distance M: Vertical relative distance R: Detection line W:Goods Ws: Target items Wt: Stacked items X :Specific direction X1:Specific direction 1st side X2: Second side in specific direction Y: Specific width direction

Claims

1. An unloading device that separates a group of target articles, which are a plurality of articles belonging to a top layer, from a group of stacked articles, which are a plurality of articles stacked on a loading section, a suction device having a suction section that suctions the upper surface of the target item group to hold the target item group; a moving device that moves the placement section and the suction section relatively in a specific direction along the horizontal direction and in an up-down direction; and a control device that controls the suction device and the moving device, one side of the specific direction is a specific direction first side, the other side of the specific direction is a specific direction second side, the direction along the horizontal direction and perpendicular to the specific direction is a specific width direction, the vertical dimension of the articles constituting the target article group is an article height, and the surface of the suction section that contacts the upper surface of the target article group is a suction surface, an article detection device that is spaced a specific distance below the suction surface and detects the article that crosses a detection line that is set along the specific width direction at a position adjacent to the suction surface on the first side in the specific direction, The control device acquires control information for calculating a vertical relative distance, which is the relative distance in the vertical direction between the upper surface of the target item group and the suction surface, and executes a specific direction movement process in which the movement device is operated to move the suction unit toward the specific direction first side relative to the placement unit from a state in which the vertical relative distance based on the control information is greater than the greater of the item height and the specific distance and is smaller than the length of the item height plus the specific distance, and the detection line is located on the specific direction second side relative to the target item group, until the detection line is located on the specific direction first side relative to the target item group; An unloading device that prohibits the operation of the moving device to move the suction unit closer to the group of target items in the vertical direction if the item detection device detects the item while the specific direction movement process is being executed.

2. The unloading device described in claim 1, wherein if the item detection device does not detect the item during the specific direction movement process, after the specific direction movement process is performed, the control device operates the moving device to move the suction section closer to the target item group in the vertical direction, stops the moving device after the suction surface contacts the upper surface of the target item group, causes the suction section to suction the upper surface of the target item group, and then operates the moving device to increase the distance between the upper surface of the placement section and the suction surface, thereby separating the target item group from the stacked item group.

3. The unloading device according to claim 1 or 2, wherein the specific distance is set to be equal to or greater than the maximum error in the vertical relative position between the placement section and the suction section by the moving device and equal to or less than the height of the item.

4. the moving device is configured to move the suction unit in the specific direction, the specific width direction, and the up-and-down direction; the object detection device is connected to the suction unit so as to move integrally therewith, A place where the placement unit is arranged is set as a take-out area, a transfer destination area is set as a place adjacent to the take-out area on one side in the specific width direction, and a waiting area is set as a place adjacent to the take-out area on a second side in the specific direction, The unloading device described in claim 1 or 2, wherein the control device separates the target group of items from the stacked group of items on the storage unit arranged in the removal area, then performs a transfer process in which the suction unit and the moving device are operated to move the separated target group of items to the destination area and place them in the destination area, and then operates the moving device to move the suction unit to the waiting area before starting the next specific direction movement process.

5. Further provided is a height detection device for detecting an initial state height, which is the vertical dimension of the stacked article group in an initial state before separation of the target article group has been performed even once, The control device When separating the first group of target items from the group of stacked items in the initial state, the control information including the initial state height detected by the height detection device is acquired, and an initial specific direction movement process is performed in which the control information is obtained so that the vertical relative distance based on the control information is greater than zero and less than the specific distance, and the detection line is positioned on the second side of the target group of items in the specific direction, and the movement device is operated to move the suction unit toward the first side of the specific direction relative to the placement unit, until the detection line is positioned on the first side of the target group of items in the specific direction, An unloading device as described in claim 1 or 2, wherein if there is an area in which the item detection device does not detect the item during execution of the initial specific direction movement process, the operation of the movement device that moves the suction section closer to the group of target items in the vertical direction is prohibited.

6. Further provided is a height detection device for detecting an initial state height, which is the vertical dimension of the stacked article group in an initial state before separation of the target article group has been performed even once, The control information includes information on the initial state height detected by the height detection device, information on the initial number of layers which is the number of layers of the stacked goods group in the initial state, and information on the number of separated layers which is the number of layers of the target goods group which have already been separated from the same stacked goods group, The control device calculates the vertical relative distance by dividing the initial state height by the initial number of tiers, setting the value obtained by multiplying the initial state height by the number of separated tiers as the item height, setting the value obtained by multiplying the item height by the number of separated tiers as the separated height, and setting the value obtained by subtracting the separated height from the initial state height as the vertical dimension of the currently stacked group of items.

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