Position setting device for setting positions of stacked workpieces and robot device equipped with the position setting device

Abstract

A position setting device for setting a position where a second workpiece is stacked on the upper side of a plurality of first workpieces is provided. The position setting device includes a search unit (54) that searches for a position where the second workpiece is allowed to be arranged on the upper side of the plurality of first workpieces. The search unit (54) includes a determination unit (55) that determines whether it is allowed to arrange the second workpiece in a manner supported by the first workpiece and the other first workpieces when the height of the upper surface of one first workpiece is different from the height of the upper surface of the other first workpieces. The determination unit (55) allows the second workpiece to be arranged in a manner supported by the first workpiece and the other first workpieces when the height difference is within a determination range.

Description

Technical Field

[0001] The present invention relates to a position setting device for setting the position of stacked workpieces and a robot device equipped with the position setting device. Background Art

[0002] When conveying articles to a destination, the articles may be conveyed using a container or a pallet, etc. In this case, a plurality of articles are arranged in a predetermined area inside the container or in a predetermined area on the upper side of the pallet.

[0003] Conventional technology has known a robot device for placing articles in a predetermined area (e.g., Japanese Patent Application Publication No. 2019-181620 and International Publication No. 2017 / 149616). Furthermore, a robot device is known for stacking articles in multiple layers when conveying them (e.g., Japanese Patent Application Publication No. 7-291451 and Japanese Patent Application Publication No. 11-59909). Furthermore, the following control is known (e.g., International Publication No. 2017 / 061632): when stacking articles using a robot device, multiple types of articles of different sizes are stacked.

[0004] Furthermore, when stacking multiple types of items, the order in which they should be stacked may not be determined. To address this issue, a robot device is known that detects the size of the workpiece and arranges the items accordingly (e.g., Japanese Patent Application Laid-Open No. 62-251811 and Japanese Patent No. 6267175).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-181620

[0008] Patent Document 2: International Publication No. 2017 / 149616

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 7-291451

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 11-59909

[0011] Patent Document 5: International Publication No. 2017 / 061632

[0012] Patent Document 6: Japanese Patent Application Laid-Open No. 62-251811

[0013] Patent Document 7: Japanese Patent No. 6267175 Summary of the Invention

[0014] Problems to be solved by the invention

[0015] The process of placing items in a designated area of ​​a container or similar device is called picking. When placing multiple types of items in a container or similar device, the sizes of the items and the order in which they are to be stacked are sometimes predetermined. In this case, a pattern for stacking the items can be pre-generated, and the items can be arranged based on this pattern.

[0016] On the other hand, the number of items placed in a container, etc., used to transport items, the size of the items, and the order in which they are stacked are sometimes undetermined. For example, the types and number of items in each customer's shipping order may vary. This process of placing multiple types of items in a container, etc., according to an order, is called order picking. In this case, it becomes difficult for a robotic device to control the position of the stacked items. In most cases, workers stack the items manually.

[0017] In particular, when placing items on top of items already placed in a container, the items may sometimes scatter. When placing items, it is necessary to determine the placement of the items so that they do not scatter. Furthermore, it is ideal to place a large number of items in a container. However, without determining the size of the items, the number of items, and the order in which they are to be placed, it is difficult to determine the placement of the items efficiently. Furthermore, it is difficult to determine the placement of the stacked items so that they do not scatter.

[0018] Solutions for solving problems

[0019] A first embodiment of the present disclosure is a position setting device for setting a position at which a second workpiece is stacked above a plurality of first workpieces. The position setting device includes a sensor for detecting the shape of the second workpiece. The position setting device includes a shape detection unit that detects the shape of the second workpiece based on output from the sensor, and an acquisition unit that acquires the shapes and positions of the plurality of first workpieces. The position setting device includes a search unit that searches for a position at which the second workpiece is permitted to be arranged above the plurality of first workpieces. Each of the first and second workpieces has an upper surface and a lower surface. A determination range for the difference in height between the upper surface of one first workpiece and the upper surface of the other first workpieces is predetermined. The search unit includes a determination unit that, when the height of the upper surface of one first workpiece differs from the height of the upper surface of the other first workpieces, determines whether it is permitted to arrange the second workpiece so that it is supported by both the first workpiece and the other first workpieces. If the height difference is within the determination range, the determination unit permits the second workpiece to be arranged so that it is supported by both the first workpiece and the other first workpieces. The determination unit prohibits the second workpiece from being arranged so as to be supported by both the one first workpiece and the other first workpiece when the difference in height exceeds a determination range.

[0020] A second embodiment of the present disclosure is a robotic device equipped with the aforementioned position setting device. The robotic device includes: a work tool for gripping a second workpiece; a robot for moving the work tool; and a control device for controlling the work tool and the robot. The control device detects the position and posture of the second workpiece based on the output of a sensor. Based on the position and posture of the second workpiece, the control device drives the robot to grip the second workpiece. The control device drives the robot to transport the second workpiece to the position for positioning the second workpiece set by the position setting device.

[0021] Effects of the Invention

[0022] According to the aspect of the present disclosure, it is possible to provide a position setting device for setting a position at which a second workpiece is stacked on an upper side of a plurality of first workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a perspective view of the robot device in the embodiment.

[0024] Figure 2 It is a block diagram of a robotic device.

[0025] Figure 3 This is a perspective view of the container and workpieces when the first layer of workpieces is placed in the container.

[0026] Figure 4 This is a top view of the container for explaining the first step in the control for arranging the first layer of workpieces in the container.

[0027] Figure 5 This is a plan view of the container for explaining the second step in the control for arranging the first layer of workpieces in the container.

[0028] Figure 6 This is a top view of the container for explaining the third step in the control for arranging the first layer of workpieces in the container.

[0029] Figure 7 This is a top view of the container for explaining the fourth step in the control for arranging the first layer of workpieces in the container.

[0030] Figure 8 This is a side view of the first workpiece and the second workpiece, illustrating an example in which stacking of the second workpiece is permitted.

[0031] Figure 9 This is a side view of the first workpiece and the second workpiece, illustrating an example in which stacking of the second workpiece is permitted.

[0032] Figure 10 This is a side view of the first workpiece and the second workpiece, illustrating an example in which stacking of the second workpiece is prohibited.

[0033] Figure 11 This is a side view of the first workpiece and the second workpiece when the second workpiece is arranged on the upper side of the first workpiece.

[0034] Figure 12 This is a side view of an example in which the second workpiece can be arranged on the upper side of the first workpiece.

[0035] Figure 13 This is a side view of an example in which it is prohibited to arrange the second workpiece on the upper side of the first workpiece.

[0036] Figure 14 This is a perspective view of the first workpiece and the second workpiece when the second workpiece is arranged on the upper side of the first workpiece.

[0037] Figure 15 It is a plan view illustrating a region facing the first workpiece when stacking of the second workpiece is permitted.

[0038] Figure 16 It is a plan view illustrating a region facing the first workpiece when stacking of the second workpiece is prohibited.

[0039] Figure 17 It is a plan view illustrating a region facing the first workpiece when stacking of the second workpiece is permitted.

[0040] Figure 18 It is a plan view illustrating a region facing the first workpiece when stacking of the second workpiece is permitted.

[0041] Figure 19 It is a plan view illustrating a region facing the first workpiece when stacking of the second workpiece is permitted.

[0042] Figure 20 This is a plan view of the workpiece and the container for explaining the first step in the control for arranging the second layer of workpieces in the container.

[0043] Figure 21 This is a plan view of the workpiece and the container for explaining the second step in the control for arranging the second layer of workpieces in the container.

[0044] Figure 22 This is a plan view of the workpiece and the container for explaining the third step in the control for arranging the second layer of workpieces in the container.

[0045] Figure 23 This is a plan view of the workpiece and the container for explaining the fourth step in the control for arranging the second layer of workpieces in the container.

[0046] Figure 24 This is a perspective view of the container and the workpieces when the second workpiece is arranged on the upper side of the first workpiece.

[0047] Figure 25 This is a plan view of the workpieces and the container for explaining the fifth step in the control for arranging the second layer of workpieces in the container.

[0048] Figure 26 This is a plan view of the workpiece and the container for explaining the sixth step in the control for arranging the second layer of workpieces in the container.

[0049] Figure 27 This is a plan view of the workpieces and the container for explaining the seventh step in the control for arranging the second layer of workpieces in the container.

[0050] Figure 28 This is a top view of the workpiece when an allowance is added to the workpiece dimensions.

[0051] Figure 29 It is a perspective view of another workpiece in the embodiment. DETAILED DESCRIPTION

[0052] Reference Figures 1 to 29 The following describes a position setting device and a robot equipped with the position setting device according to an embodiment. The position setting device of this embodiment sets the position of a workpiece within a container. Specifically, the position setting device sets the position where a second workpiece is stacked above a plurality of first workpieces arranged in the container. The robot then transports the workpiece to the position set by the position setting device within the container.

[0053] Figure 1It is a perspective view of the robot device in this embodiment. Figure 2 This is a block diagram of the robot device in this embodiment. Figure 1 and Figure 2 The robot device 3 places the workpiece 69, which is arranged on the upper surface of the top plate 79 of the frame 78, into the container 60. The workpiece 69 in this embodiment is a rectangular box. The container 60 functions as a support member that supports the workpiece 69 from the bottom. The container 60 in this embodiment has a box shape and an upper opening. The support member for the workpiece 69 is not limited to the container 60, and any member that supports the workpiece can be used. For example, a pallet for transporting the workpiece 69 can be used as the support member.

[0054] The robot device 3 includes: a hand 5 as a working tool for gripping a workpiece 69; and a robot 1 for moving the hand 5. The robot device 3 includes a control device 2 for controlling the robot 1 and the hand 5. The hand 5 of this embodiment is a suction hand that grips the upper surface of the workpiece 69 by suction. The working tool mounted on the robot 1 is not limited to this method. Any working tool that can grip a workpiece can be used by the robot device 3. For example, a working tool that grips a workpiece with claws facing each other or a working tool that grips a workpiece by magnetic force can be used.

[0055] The robot 1 of this embodiment is a multi-joint robot including a plurality of joints 18. The robot 1 includes an upper arm 11 and a lower arm 12. The lower arm 12 is supported by a rotating base 13. The rotating base 13 is supported by a base 14. The robot 1 includes a wrist 15 connected to the end of the upper arm 11. The wrist 15 includes a flange 16 for fixing the hand 5. The robot is not limited to this embodiment, and any robot that can move a working tool can be used.

[0056] For the robot device 3 of this embodiment, a world coordinate system 81 is set that remains fixed when the position and posture of the robot 1 change. The world coordinate system 81 is also called a reference coordinate system. The position of the origin of the world coordinate system 81 is fixed, and the orientation of the coordinate axes of the world coordinate system 81 is fixed. In addition, for the robot device 3, a tool coordinate system having an origin set at an arbitrary position of the working tool is set. The position and posture of the tool coordinate system change with the hand 5. For example, the position of the robot 1 corresponds to the position of the top point of the tool (for example, the position of the origin of the tool coordinate system). In addition, the posture of the robot 1 corresponds to the posture of the tool coordinate system relative to the world coordinate system 81.

[0057] In the robot device 3 of this embodiment, the control device 2 functions as a position setting device. The control device 2 includes a sensor for detecting the shape of a workpiece 69. The sensor in this embodiment is a vision sensor 30 for generating three-dimensional position information of measurement points corresponding to the surface of the workpiece 69. The vision sensor 30 in this embodiment is a stereo camera consisting of a first camera 31 and a second camera 32. The vision sensor 30 also includes a projector 33 that projects patterned light, such as stripes, onto the workpiece.

[0058] The vision sensor 30 is fixed to the base of the hand 5. The position and posture of the vision sensor 30 change as the position and posture of the robot 1 change. The vision sensor 30 is not limited to this configuration and can be configured to image the workpiece 69 placed on the stage 78. For example, the vision sensor 30 can also be fixed to a fixing member fixed to the stage.

[0059] The robot 1 of this embodiment includes a robot drive device 21 that drives components such as the upper arm 11. The robot drive device 21 includes multiple drive motors for driving the upper arm 11, the lower arm 12, the rotating base 13, and the wrist 15. The hand 5 includes a hand drive device 22 that drives the hand 5. The hand drive device 22 of this embodiment uses air pressure to drive the hand 5. The hand drive device 22 includes a pump and a solenoid valve for reducing the pressure in the space inside the suction pad.

[0060] The control device 2 includes a processing unit (computer) including a CPU (Central Processing Unit) as a processor. The processing unit includes RAM (Random Access Memory) and ROM (Read Only Memory), etc., which are interconnected with the CPU via a bus. The robot device 3 of this embodiment automatically transports a workpiece 69 based on an operation program 41. The robot drive device 21 and the hand drive device 22 are controlled by the control device 2.

[0061] The control device 2 includes a storage unit 42 that stores information related to the control of the robot 3. The storage unit 42 can be composed of a storage medium capable of storing information, such as volatile memory, nonvolatile memory, or hardware. The control device 2 receives input of an operation program 41, which has been pre-created to operate the robot 1. The operation program 41 is stored in the storage unit 42.

[0062] The control device 2 includes a motion control unit 43 that issues motion commands. Based on the motion program 41, the motion control unit 43 issues motion commands to the robot drive unit 44 for driving the robot 1. The robot drive unit 44 includes circuits for driving the drive motor. Based on the motion commands, the robot drive unit 44 supplies power to the robot drive device 21. Furthermore, the motion control unit 43 issues motion commands to the hand drive unit 45 for driving the hand drive device 22. The hand drive unit 45 includes circuits for driving a pump, etc. Based on the motion commands, the hand drive unit 45 supplies power to the pump, etc.

[0063] The motion control unit 43 corresponds to a processor driven according to the motion program 41. The processor reads the motion program 41 and executes control determined by the motion program 41, thereby functioning as the motion control unit 43.

[0064] The robot 1 includes a state detector for detecting the position and posture of the robot 1. In this embodiment, the state detector includes a position detector 23 mounted on the drive motor of each drive axis of the robot drive device 21. The position and posture of the robot 1 are detected based on the output of the position detector 23. The state detector is not limited to a position detector mounted on the drive motor; any detector capable of detecting the position and posture of the robot 1 can be used.

[0065] The control device 2 includes a teaching operation panel 49, which serves as an operating panel for an operator to operate the robot 3. The teaching operation panel 49 includes an input unit 49a for inputting information related to the robot 1, hand 5, and visual sensor 30. The input unit 49a is composed of components such as a keyboard and a dial. The teaching operation panel 49 includes a display unit 49b for displaying information related to the control of the robot 3. The display unit 49b is composed of a display panel such as a liquid crystal display panel.

[0066] The control device 2 includes a processing unit 51 that generates an operation command for the vision sensor 30 to image the workpiece 69 and place the workpiece 69 in the container 60. The processing unit 51 includes a shape detection unit 52 that detects the shape of the workpiece 69 being transported to the container 60 based on the output of the vision sensor 30. The processing unit 51 includes an acquisition unit 53 that acquires the shape and position of the workpiece 69 already placed in the container 60. The processing unit 51 includes a search unit 54 that searches for a position to place the workpiece 69 transported by the robot 1 based on the position of the workpiece 69 already placed in the container 60. The search unit 54 includes a determination unit 55 that determines whether a position in the container 60 where the workpiece 69 transported by the robot 1 is permitted to be placed. The search unit 54 includes a selection unit 56 that selects a position to place the workpiece 69 if multiple positions in the container 60 allow the workpiece 69 to be placed.

[0067] The processing unit 51 also includes an imaging control unit 57 that issues an image capturing command to the visual sensor 30. The processing unit 51 also includes an operation command unit 58 that generates an operation command for driving the robot 1 based on the position of the workpiece 69 set by the search unit 54 for the container 60.

[0068] The processing unit 51 described above corresponds to a processor driven according to the operating program 41. In particular, the shape detection unit 52, acquisition unit 53, search unit 54, determination unit 55, and selection unit 56 correspond to processors driven according to the operating program 41. Furthermore, the imaging control unit 57 and the operation instruction unit 58 correspond to processors driven according to the operating program 41. The processor reads the operating program 41 and implements the control determined by the operating program 41, thereby functioning as each unit.

[0069] The shape detection unit 52 of the processing unit 51 detects the shape of the workpiece 69 based on the output of the vision sensor 30. The shape detection unit 52 acquires two-dimensional images captured by the two cameras 31 and 32. The shape detection unit 52 calculates the distance from the vision sensor 30 to the specific portion based on the parallax between the specific portion in the image captured by the first camera 31 and the image captured by the second camera 32.

[0070] Furthermore, the shape detection unit 52 can calculate the three-dimensional position of a measurement point set on the surface of the workpiece 69 based on the distance to the specific portion and the positions of the two cameras 31 and 32. The shape detection unit 52 can detect the shape of the workpiece 69, including its dimensions, based on the positional information of the measurement point set on the surface of the workpiece 69. Furthermore, the shape detection unit 52 can detect the position and posture of the workpiece 69.

[0071] Furthermore, the sensor for detecting the shape of a workpiece is not limited to a stereo camera; any sensor capable of detecting the shape of a workpiece can be used. For example, a sensor such as a TOF (Time of Flight) camera capable of detecting the three-dimensional position of a measurement point on the surface of a workpiece can be used. Alternatively, a contact sensor capable of detecting the shape of a workpiece by bringing a probe into contact with the workpiece can be used.

[0072] The robot device 3 of this embodiment controls the placement of the workpiece 69 placed on the stage 78 into the container 60. The workpiece 69 is supplied to the stage 78 by an operator or a conveying device. Before the hand 5 of the robot device 3 grasps the workpiece 69, the robot 1 places the visual sensor 30 above the workpiece 69 placed on the stage 78. The camera control unit 57 issues a command to the visual sensor 30 to capture an image. The visual sensor 30 captures an image of the workpiece 69. The shape detection unit 52 detects the shape of the workpiece 69, as well as the position and posture of the workpiece 69. In particular, the shape detection unit 52 of this embodiment detects the size and height of the side of the workpiece 69 when the workpiece 69 is viewed from above.

[0073] A camera coordinate system is set for the vision sensor 30. The shape detection unit 52 can calculate the position of a measurement point set on the surface of the workpiece 69 using the coordinate values ​​of the camera coordinate system. Based on the position and posture of the robot 1, the shape detection unit 52 can convert the position information of the measurement point on the workpiece 69 expressed in the camera coordinate system into position information of the measurement point on the workpiece 69 expressed in the world coordinate system 81. Based on the position information of the measurement point, the size of the workpiece can be detected.

[0074] The position of the top plate 79 of the stand 78 can be predetermined. The shape detection unit 52 can detect the height of the workpiece 69 based on the difference between the top plate 79 and the upper surface of the workpiece 69. The shape detection unit 52 is not limited to this method and can be controlled to detect the shape and height of the workpiece surface. For example, the robot can change the position and posture of the vision sensor to capture images from an oblique direction of the workpiece. This control enables detection of both planar and lateral shapes.

[0075] In this embodiment, the shape information of all workpieces 69 arranged inside the container 60 and the positions of the workpieces 69 in the container 60 are stored in the storage unit 42. The shape information of the workpieces 69 includes the dimensions of the workpieces 69. In this embodiment, the shape information of the workpieces 69 includes the lengths of the respective sides of the rectangular workpieces 69. The positions of the workpieces 69 can be exemplified by, for example, the center of gravity of the shape of the top surface of the workpieces 69 or the center of gravity of the three-dimensional shape of the workpieces 69.

[0076] The acquisition unit 53 of the processing unit 51 acquires information about the shape and position of the workpiece 69 already placed in the container 60. The search unit 54 sets the position at which the new workpiece 69 is to be placed based on the information about the workpiece 69 already placed in the container 60. The motion command unit 58 issues a command to the motion control unit 43 to drive the robot 1 to grasp the workpiece 69 based on the position and posture of the workpiece 69 placed on the stage 78. The motion command unit 58 issues a command to the motion control unit 43 to drive the robot 1 to transport the workpiece 69 to the position set by the search unit 54. The motion control unit 43 drives the robot 1 and the hand 5 based on the motion command from the motion command unit 58, thereby transporting the workpiece 69 from the stage 78 to the container 60.

[0077] Furthermore, in this embodiment, the position of the container 60 on the top plate 79 of the stand 78 is predetermined. The position and shape of the bottom surface of the container 60, as well as the position and shape of the wall surface of the container 60, are predetermined. That is, the configuration area of ​​the container 60 for arranging a plurality of workpieces 69 is predetermined. However, sometimes the position of the container 60 is slightly offset when the container 60 is placed on the top plate 79. The robot device 3 of this embodiment is capable of capturing an image of the container 60 using the visual sensor 30 after the container 60 is placed on the top plate 79. Then, the position of the container 60 can be detected to correct the position and shape of the bottom surface of the container 60, as well as the position and shape of the wall surface. That is, the configuration area for arranging the workpieces 69 can also be corrected.

[0078] In this embodiment, the size of the workpieces 69 placed in the container 60, the number of workpieces 69, and the order in which the workpieces 69 are stacked are not determined. The robot 3 places multiple types of workpieces 69 in the container 60. In this embodiment, the workpieces 69 have parallel upper and lower surfaces. The workpieces 69 vary in size. Specifically, the upper and lower surfaces of each workpiece 69 differ in size and height. Alternatively, workpieces 69 of the same size may be included.

[0079] The following description will focus on the control performed by the processing unit 51 for determining the position at which the workpieces are to be placed in the container 60. In this embodiment, for each workpiece 69 transported to the stage 78, the position at which it is to be placed is searched in the container 60. Before the search unit 54 searches for the position at which the workpieces are to be placed, the vision sensor 30 captures an image of the workpiece 69 placed on the stage 78. The shape detection unit 52 detects the shape, position, and posture of the workpiece 69. The acquisition unit 53 acquires information on the shape and position of the workpiece 69 placed in the container 60 from the storage unit 42. After the search unit 54 determines the position at which the workpiece 69 is to be placed, the storage unit 42 stores the shape and position of the workpiece 69 placed in the container 60. The robot 3 grasps the workpiece 69 placed on the stage 78 using its hand 5. The robot 3 places the workpiece 69 at the position determined by the search unit 54. This control can be performed each time a workpiece 69 is placed in the container 60.

[0080] exist Figure 3 , a perspective view of the workpieces and the container is shown when the first layer of workpieces is arranged in the container. The first layer of workpieces 61a to 61e is arranged inside the container 60. The workpieces are arranged in multiple layers inside the container 60. That is, the workpieces are stacked inside the container 60. In this embodiment, with respect to the multiple layers of workpieces arranged in the container 60, the workpiece arranged on the lower side is referred to as the first workpiece, and the workpiece stacked on the upper side of the first workpiece is referred to as the second workpiece. The first workpiece is the lower workpiece, and the second workpiece is the upper workpiece. In this example, the workpieces 61a to 61e correspond to the first workpiece.

[0081] exist Figure 4 , a top view of a container is shown for explaining the first step of arranging the first layer of workpieces inside the container. Container 60 includes a bottom surface 60a and wall surfaces 60b to 60e extending vertically from bottom surface 60a. The first layer of workpieces is placed on bottom surface 60a of container 60. A workpiece coordinate system 82 is set for container 60. Workpiece coordinate system 82 is a fixed coordinate system for container 60. The origin of workpiece coordinate system 82 in this embodiment is located at a corner of bottom surface 60a. Search unit 54 of processing unit 51 is set at a position where first workpieces 61a to 61e are to be arranged on bottom surface 60a.

[0082] First, the search unit 54 searches for the location where the first workpiece 61b is to be placed. When the first workpiece 61b is placed in the container 60, no workpiece is placed inside the container 60. Therefore, the acquisition unit 53 acquires information about the shape and position of the container 60. In this embodiment, a base point 70 serving as a reference is pre-set at a corner of the bottom surface 60a of the container 60. The base point 70 is set where the walls 60b and 60c meet the bottom surface 60a. Preferably, the base point 70 is set at a location where the robot 1 rarely moves to move the workpiece.

[0083] Furthermore, a base point 71 is pre-set at a corner of the lower surface of workpiece 61b. The search unit 54 positions workpiece 61b so that base point 71 overlaps with base point 70. In the figure, if base points overlap, one base point is indicated at a slightly offset position. The determination unit 55 determines whether workpiece 61b interferes with other workpieces or container 60. The determination unit 55 determines that workpiece 61b does not interfere with other workpieces or container 60. The search unit 54 then determines the position of workpiece 61b.

[0084] exist Figure 5 2 shows a top view of a container, illustrating the second step in the control for arranging the first layer of workpieces within the container. The processing unit 51 sets the position for arranging the first workpiece 61c. The search unit 54 arranges the container 60 so that the base point 71 of the workpiece 61c overlaps the base point 70 of the container 60. Because the workpiece 61b is already arranged within the container 60, the determination unit 55 determines that the workpiece 61c interferes with the workpiece 61b.

[0085] The search unit 54 moves the workpiece 61c in a predetermined direction. In this embodiment, control is performed to move the workpiece 61c in the X-axis direction of the workpiece coordinate system 82 (along the short side of the container 60), as indicated by arrow 90. The search unit 54 moves the workpiece 61c by a predetermined small distance at a time. The determination unit 55 determines whether the workpiece 61c interferes with the workpiece 61b and the container 60. The search unit 54 repeats the movement and determination of each small distance.

[0086] exist Figure 6 2 shows a top view of the container, illustrating the third step in the control for arranging the first layer of workpieces in the container. In this example, when workpiece 61c moves to a position where its side surface contacts the side surface of workpiece 61b, determination unit 55 determines that workpiece 61c does not interfere with workpiece 61b or container 60. Determination unit 55 decides to place workpiece 61c at this position.

[0087] exist Figure 7is a top view of the container illustrating the fourth step in the control for arranging the first layer of workpieces in the container. Next, when arranging the first workpiece 61d, the search unit 54 arranges the workpiece 61d so that the base point 71 set on the workpiece 61d overlaps the base point 70 of the container 60. The determination unit 55 determines that the workpiece 61d interferes with the workpiece 61b at this position.

[0088] Next, the search unit 54 moves the workpiece 61d in a direction parallel to the X-axis of the workpiece coordinate system 82 and determines whether interference occurs. This control is repeated until the workpiece 61d interferes with the wall 60d. Even if the workpiece 61d's surface contacts the wall 60d, the workpiece 61d still interferes with the other workpiece 61c. Therefore, the search unit 54 returns the workpiece 61d to a position where the base point 71 overlaps the base point 70 of the container 60.

[0089] Next, the search unit 54 moves the workpiece 61d in a direction parallel to the Y-axis of the workpiece coordinate system 82 (along the long side of the container 60), as indicated by arrow 83. The search unit 54 moves the workpiece 61d by small distances. Next, the search unit 54 searches for a position where the workpiece 61d can be placed without interference, while moving the workpiece 61d by small distances in a direction parallel to the X-axis of the workpiece coordinate system 82, as indicated by arrow 84. This movement is continued until the workpiece 61d interferes with the wall 60d of the container 60.

[0090] In this manner, the search unit 54 repeatedly moves the workpiece coordinate system 82 in the X-axis direction and the Y-axis direction. The search unit 54 sets the position where the workpiece 61d can be placed without interfering with other objects as the position where the workpiece 61d can be placed. In this example, the workpiece 61d can be placed at a position where the side surface of the workpiece 61d contacts the side surface of the workpiece 61b and the wall surface 60b of the container 60. The search unit 54 determines the position where the workpiece 61d can be placed.

[0091] The control for determining the position of the first workpiece in order to place the next first workpiece on the bottom surface 60a of the container 60 is similar to the control for setting the position of the first workpiece described above. The search unit 54 ends this control when the workpiece interferes with the wall surface 60e.

[0092] In this way, the search unit 54 can move the workpiece a small distance at a time in a predetermined direction and determine whether it interferes with other objects. In the example here, the search unit 54 repeatedly moves the workpiece coordinate system 82 in the X-axis direction and the Y-axis direction and determines whether the workpiece can be arranged. Through this control, the position of the first workpiece 61a to 61e can be set on the bottom surface 60a of the container 60. In addition, since the position of the workpiece is set based on the base point 70 of the container 60, multiple workpieces can be arranged in a manner close to the base point 70. In this embodiment, the base point 70 is set at a position where the drive amount of the robot 1 is small. Therefore, when transporting the first workpiece 61a to 61e, the drive amount of the robot 1 is small. As a result, the first workpiece 61a to 61e can be transported in a short time.

[0093] Alternatively, if it is determined that there is no position where the workpiece does not interfere with other objects, the workpiece may be rotated at a predetermined rotation angle and the same control may be applied to the rotated state. In this embodiment, the planar shape of the workpiece is a rectangle. Therefore, the above-mentioned control may be applied to the workpiece after it has been rotated 90° around a rotation axis perpendicular to the bottom surface 60a. For example, after the workpiece is moved along the Y-axis of the workpiece coordinate system 82 and it is determined that the workpiece interferes, the workpiece may be rotated 90° and then the movement in the Y-axis direction and the determination of the interference of the workpiece may be applied.

[0094] The control of the position at which the workpiece is placed on the bottom surface 60a of the container 60 is not limited to the above-described method; any other control method can be employed. For example, the search unit can detect the corner of the exposed area of ​​the container bottom surface. The search unit can then position the workpiece so that its base point overlaps with the corner and determine whether interference occurs.

[0095] Next, the control of stacking the second workpiece on top of the first workpiece will be described. In this embodiment, the storage unit 42 stores information on the shapes of the first workpieces 61a to 61e placed in the container 60 and information on the positions of the first workpieces 61a to 61e within the container 60. The acquisition unit 53 acquires information on the workpieces 61a to 61e placed within the container 60 from the storage unit 42.

[0096] exist Figure 8 , which illustrates a side view of the first and second workpieces for explaining an example in which the second workpiece is allowed to be arranged on the upper side of a plurality of first workpieces. Figure 8 In the illustrated example, the determination unit 55 of the search unit 54 determines whether or not it is permitted to arrange the second workpiece 64a above the lower first workpieces 63a, 63b, and 63c.

[0097] In this embodiment, there are workpieces of various heights. When multiple workpieces are placed in the container 60, the heights of the upper surfaces of the workpieces may differ from each other. The determination unit 55 allows the second workpiece to be placed on top of multiple first workpieces when the difference in the height of the upper surfaces of the first workpieces is small. In other words, the determination unit 55 determines that the positions of the upper surfaces of the workpieces are substantially the same when the positions of the upper surfaces of the workpieces are slightly different. As the height of the upper surface of the workpiece, for example, the height from the bottom surface 60a of the container 60 can be used. Alternatively, the coordinate value in the world coordinate system 81 can be used as the height of the upper surface of the workpiece.

[0098] In this embodiment, a determination range for the difference in height between the top surface of one first workpiece and the top surface of another first workpiece is predetermined. The determination unit 55 selects one workpiece 63a as a reference workpiece and sets a determination range R for the position of the top surface 63aa of the workpiece 63a. Then, if the difference in height between the top surface 63aa of the first workpiece 63a and the top surface 63ba of the other workpiece 63b falls within the determination range, the determination unit 55 allows the second workpiece 64a to be positioned so that it is supported by both the first workpiece 63a and the first workpiece 63b. Specifically, if the top surface 63ba of the first workpiece 63b is positioned within the determination range R, the determination unit 55 allows the second workpiece 64a to be positioned so that it straddles the workpieces 63a and 63b.

[0099] On the other hand, if the height difference between the other first workpiece 63c and the first workpiece 63a exceeds the determination range R, the determination unit 55 determines that the height of the upper surface 63ca is different from the height of the upper surface 63aa. The determination unit 55 prohibits the second workpiece 64a from being arranged so as to be supported by both the first workpiece 63a and the first workpiece 63c. Alternatively, if the height of the first workpiece 63c is less than the determination range R, the determination unit 55 determines that the second workpiece 64a is not in contact with the second workpiece 64a.

[0100] exist Figure 9 , which illustrates a side view of the first and second workpieces for explaining an example in which the second workpiece is allowed to be arranged on the upper side of a plurality of first workpieces. Figure 9 In the example shown, first workpiece 63a and first workpiece 63b are arranged separately from each other. First workpiece 63c is arranged between workpieces 63a and 63b. In this case, upper surface 63ba of workpiece 63b is also located within determination range R relative to upper surface 63aa of workpiece 63a. Therefore, determination unit 55 determines that upper surface 63ba and upper surface 63aa are at substantially the same height. Determination unit 55 allows second workpiece 64a to be arranged so that it is supported by upper surface 63aa of workpiece 63a and upper surface 63ba of workpiece 63b.

[0101] exist Figure 10 , which illustrates a side view of the first and second workpieces for explaining an example in which it is prohibited to arrange the second workpiece on the upper side of a plurality of first workpieces. Figure 10 In the example shown, the determination unit 55 determines whether the second workpiece 64a can be placed above the first workpieces 63a, 63c, and 63d. The upper surface 63da of the workpiece 63d is located outside the determination range R relative to the upper surface 63aa of the workpiece 63a. Therefore, the determination unit 55 prohibits the second workpiece 64a from being placed so that it is supported by the first workpieces 63a and 63d. In this example, the upper surface 63da of the workpiece 63d is located above the upper limit of the determination range R. Therefore, the determination unit 55 determines that the second workpiece 64a will interfere with the first workpiece 63d when the second workpiece 64a is placed on the upper surface 63aa of the first workpiece 63a.

[0102] exist Figure 11 3 shows a side view when the second workpiece is actually arranged on the upper side of the plurality of first workpieces. Figure 11 is Figure 8 The side view of the second workpiece 64a is shown when the second workpiece 64a is arranged on the upper side of the plurality of first workpieces 63a, 63b, and 63c. The height of the upper surface 63aa is slightly different from the height of the upper surface 63ba. Therefore, when the second workpiece 64a is arranged, the second workpiece 64a will be slightly tilted. In the control of this embodiment, this slight tilt is allowed. In this case, the search unit 54 will also be regarded as Figure 8 As shown, calculations are performed while the second workpiece 64a is not tilted. That is, even when controlling the placement of another workpiece on the upper surface of workpiece 64a, the search unit 54 performs calculations assuming that the entire upper surface 63aa of workpiece 63a is in contact with the lower surface of workpiece 64a. The search unit 54 performs calculations assuming that the upper and lower surfaces of each workpiece are parallel to the bottom surface of the container.

[0103] The determination range related to the height difference of the workpiece's top surface is preferably set small to prevent the workpiece from being scattered. The determination range depends on the shape, size, and weight of the workpiece. For example, the determination range can be set within a range of ±5 mm relative to the position of the workpiece's top surface as a reference.

[0104] As described above, the determination unit 55 of this embodiment determines the height position of the upper surface of the first workpiece in order to stably arrange the second workpiece above the plurality of first workpieces. Furthermore, in addition to determining the height position of the upper surface of the workpiece, the determination unit 55 also determines the size and position of the area of ​​the second workpiece that faces the first workpiece.

[0105] exist Figure 12An example of allowing the second workpiece to be arranged on the upper side of the first workpiece is shown in FIG. The determination unit 55 determines whether the second workpiece 64a can be arranged on the upper side of the first workpiece 63g. In the case where the surface area of ​​the upper surface of the first workpiece is smaller than the surface area of ​​the lower surface of the second workpiece, if the second workpiece is arranged on the upper side of the first workpiece, the second workpiece will become unstable. Figure 12 In the example shown, the position of the upper surface 63ca of the workpiece 63c exceeds the determination range R relative to the upper surface 63ga of the workpiece 63g. Therefore, placement of the second workpiece 64a supported by the workpiece 63c is prohibited. On the other hand, the area of ​​the upper surface 63ga of the workpiece 63g and the lower surface 64aa of the workpiece 64a facing each other is large. In other words, the area of ​​contact between the upper surface 63ga and the lower surface 64aa is large. In this case, the determination unit 55 permits placement of the second workpiece 64a on the upper surface of the first workpiece 63g.

[0106] exist Figure 13 , an example of prohibiting the placement of a second workpiece on the upper side of a first workpiece is shown. The position of the upper surface 63fa of the first workpiece 63f exceeds the determination range R relative to the upper surface 63aa of the first workpiece 63a. On the other hand, the position of the upper surface 63ea of ​​the first workpiece 63e is within the determination range R relative to the upper surface 63aa of the first workpiece 63a. The determination unit 55 determines that the upper surface 63ea is at substantially the same height as the upper surface 63aa. However, even if the area of ​​the upper surface 63aa is added to the area of ​​the upper surface 63ea, the area of ​​the second workpiece 64a facing the first workpieces 63a and 63e is small. Therefore, if the second workpiece 64a is placed on the upper surfaces of the first workpieces 63a and 63e, the workpiece 64a will become unstable. In this case, the determination unit 55 prohibits the placement of the second workpiece 64a on the upper side of the first workpieces 63a and 63e.

[0107] The determination unit 55 permits placement of the second workpiece above the first workpiece if the area between the lower surface of the second workpiece and the upper surface of the first workpiece, which is arranged to support the second workpiece, is larger than an area obtained by multiplying the area of ​​the lower surface of the second workpiece by a predetermined ratio. On the other hand, if the area between the upper surface of the first workpiece and the lower surface of the second workpiece facing each other is smaller than an area obtained by multiplying the area of ​​the lower surface of the second workpiece by a predetermined ratio, placement of the second workpiece above the first workpiece is prohibited.

[0108] Next, determination of the area where the upper surface of the first workpiece and the lower surface of the second workpiece face each other and the position where the upper surface of the first workpiece and the lower surface of the second workpiece face each other will be described in more detail.

[0109] exist Figure 14 , a perspective view showing an example in which a second workpiece is placed on an upper side of a first workpiece. Figure 15 , a top view of the first workpiece and the second workpiece is shown. Figure 14 and Figure 15 The second workpiece 64a is arranged on the upper side of the first workpiece 63h. The area of ​​the upper surface 63ha of the first workpiece 63h is smaller than the area of ​​the lower surface 64aa of the second workpiece 64a.

[0110] The determination unit 55 of this embodiment sets a plurality of regions 75 obtained by dividing the lower surface 64aa of the second workpiece 64a. In this example, the regions 75 are formed into rectangular shapes. Furthermore, the determination unit 55 divides the lower surface 64aa of the second workpiece 64a into equal parts. If the number of regions 75 facing the first workpiece 63h exceeds a predetermined determination value, the determination unit 55 determines that the upper surface 63ha of the first workpiece 63h faces the lower surface 64aa of the second workpiece 64a with a sufficient area. The determination unit 55 permits the second workpiece 64a to be placed above the first workpiece 63h.

[0111] In this embodiment, when at least a portion of the region 75 faces the upper surface 63ha of the first workpiece 63h, it is determined that the region 75 faces the first workpiece 63h. Figure 15 The position of the second workpiece 64a shown in FIG. 1 is a diagram showing a position of 16 areas 75 on the lower surface 64aa of the workpiece 64a. The determination value for the number of areas 75 is set to 16, which is 100% of the total number of areas 75. That is, the second workpiece 64a is allowed to be arranged when all areas 75 face the first workpiece 63h. In this example, all areas 75 face the first workpiece 63h. Therefore, the determination unit 55 allows the second workpiece 64a to be arranged when Figure 15 The second workpiece 64a is arranged in the position shown.

[0112] exist Figure 16 An example in which it is prohibited to arrange the second workpiece on the upper side of the first workpiece is shown in FIG. Figure 16 At the position of the second workpiece 64a shown, the number of areas 75 facing the upper surface 63ha of the first workpiece 63h is 12, which is less than the determination value. Therefore, the determination unit 55 determines that the area of ​​the second workpiece 64a facing the first workpiece 63h is small. The determination unit 55 prohibits the placement of the second workpiece 64a above the first workpiece 63h.

[0113] Furthermore, the determination unit can divide the lower surface of the second workpiece using any method to set the divided regions. For example, the determination unit can divide the lower surface into any number of regions. Furthermore, the regions can be any shape, such as triangular or hexagonal. Furthermore, the determination unit 55 can determine that each region 75 faces the first workpiece if the entire region 75 faces the first workpiece.

[0114] exist Figure 17 An example of allowing the second workpiece to be arranged on the upper side of the first workpiece is shown in FIG. The determination unit 55 determines whether it is allowed to arrange the second workpiece 64a on the upper side of the first workpieces 63i, 63j, 63k. The first workpieces 63i, 63j, 63k are arranged separately from each other. The difference in height of the upper surface of the first workpieces 63i, 63j, 63k is within the determination range R. In the example here, when more than 80% (more than 13) of the 16 areas 75 are facing the first workpieces 63i, 63j, 63k, the second workpiece 64a is allowed to be arranged. Figure 17 In the position of the second workpiece 64a shown, the 13 regions 75 face the first workpieces 63i, 63j, and 63k. Therefore, the second workpiece 64a can be arranged above the first workpieces 63i, 63j, and 63k.

[0115] Next, the determination unit 55 of this embodiment detects the position of a region of the lower surface of the second workpiece that faces the upper surface of the first workpiece. Based on the position of the region, the determination unit 55 determines whether placement of the second workpiece is permitted.

[0116] exist Figure 18 An example of allowing the second workpiece to be arranged on the upper side of the first workpiece is shown in FIG. Even when the area of ​​the lower surface of the second workpiece facing the upper surface of the first workpiece is small, the second workpiece can sometimes be arranged stably. Figure 18 In the example shown, the second workpiece 64a is placed above the plurality of first workpieces 63l, 63m, 63n, and 63o.

[0117] The first workpieces 63l, 63m, 63n, and 63o are arranged to support the second workpiece 64a so as to surround the center of gravity 64ax of the shape of the lower surface of the second workpiece 64a. In this case, the determination unit 55 allows the second workpiece 64a to be placed above the first workpieces 63l, 63m, 63n, and 63o. In particular, if three or more areas 75 face the first workpieces 63l, 63m, 63n, and 63o so as to surround the center of gravity 64ax, the determination unit 55 allows the second workpiece 64a to be placed in such a position.

[0118] exist Figure 18 In the example shown, among the multiple regions 75 defined on the lower surface of the second workpiece 64a, the four corner regions 75 face the workpieces 63l, 63m, 63n, and 63o. The four corner regions 75 are arranged around the center of gravity 64ax so as to surround it. The determination unit 55 permits the placement of the second workpiece 64a at this location.

[0119] Alternatively, the determination unit 55 may allow the second workpiece to be arranged when a predetermined area 75 among the plurality of areas 75 set on the lower surface of the second workpiece faces the first workpiece. For example, the determination unit 55 may allow the second workpiece to be arranged when a predetermined part of the plurality of areas 75 arranged on the outer periphery of the second workpiece faces the first workpiece. Figure 18 In the example shown, four areas 75 arranged at the corners of the lower surface of the second workpiece 64a can be pre-specified. When these four areas 75 face the first workpieces 63l, 63m, 63n, and 63o, the determination unit 55 can arrange the second workpiece 64a at these locations.

[0120] exist Figure 19 An example of allowing the second workpiece to be arranged on the upper side of the first workpiece is shown in FIG. The difference in height between the upper surfaces of the first workpieces 63p, 63q, and 63r is within the judgment range R. In this example, 10 are determined as the judgment value of the number of areas 75 on the lower surface of the second workpiece 64a that face the first workpieces 63p, 63q, and 63r. In addition, four areas 75 arranged at the corners of the lower surface of the second workpiece 64a are specified as areas that need to face the first workpieces 63p, 63q, and 63r. Figure 19 In the illustrated example, since these two conditions are satisfied, the determination unit 55 permits the second workpiece 64a to be arranged above the first workpieces 63p, 63q, and 63r.

[0121] In this manner, the determination unit 55 can perform at least one of a determination based on the area of ​​the second workpiece facing the first workpiece and a determination based on the position of the second workpiece facing the first workpiece. By implementing this control, it is possible to determine whether the second workpiece can be stably positioned above the first workpiece. In particular, these determinations can be combined. Furthermore, by setting the area obtained by dividing the lower surface of the second workpiece, it is possible to perform a determination based on the area of ​​the workpieces facing each other through simple calculation.

[0122] exist Figure 20 , a top view of the workpiece and the container is shown for explaining the first step in the control for arranging the second workpiece on the upper side of the first workpiece. Figure 3 The following describes a specific example of placing the second layer of workpieces on top of the first layer of workpieces shown. If the search unit 54 determines that there is no location to place a workpiece on the bottom surface 60a of the container 60, it considers stacking the second workpiece on top of the first workpieces 61a to 61e already placed inside the container 60. First, a location is set for placing the second workpiece 62a on top of the first workpieces 61a to 61e.

[0123] In this embodiment, the search unit 54 determines a position for configuring the second workpiece 62a. The determination unit 55 determines whether it is permitted to configure the second workpiece 62a at a position. The determination unit 55 performs a determination on the difference in height between the upper surfaces of the plurality of first workpieces. In addition, the determination unit 55 performs a determination based on the area of ​​the region of the second workpiece facing the first workpiece and a determination based on the position of the second workpiece facing the first workpiece. In addition, the determination unit 55 determines whether the second workpiece 62a interferes with the container 60. Furthermore, when other second workpieces are configured, the determination unit 55 determines whether interference occurs with other second workpieces. The determination result of the determination unit 55 is stored in the storage unit 42 together with the position of the second workpiece.

[0124] Next, the search unit 54 moves the second workpiece 62a a small distance in a predetermined direction to the next position. The determination unit 55 then determines whether the second workpiece 62a can be placed at the next position. The search unit 54 repeats this movement and determination of the second workpiece 62a within the area enclosed by the walls 60b to 60e of the container 60. If multiple positions are available for the workpiece 62a, the selection unit 56 selects a position for placement of the second workpiece 62a based on predetermined conditions.

[0125] More specifically, the acquisition unit 53 acquires information about the shapes and positions of the workpieces 61a to 61e arranged inside the container 60 from the storage unit 42. The search unit 54 detects the workpieces with their top surfaces exposed based on the information about the workpieces 61a to 61e. That is, when the workpieces are stacked in multiple layers, the workpiece arranged on the top is detected. In this example, the workpieces 61a to 61e on the first layer correspond to the workpieces with their top surfaces exposed. The search unit 54 sets the workpieces 61a to 61e as the first workpiece. A base point 71 is set at a corner of the lower surface of the second workpiece 62a. Furthermore, the base point 70 of the container 60 moves from the bottom surface 60a to the upper surface of the first workpiece 61b.

[0126] exist Figure 21 , a top view of the workpiece and the container for explaining the second step in the control for arranging the second workpiece on the upper side of the first workpiece is shown. The search unit 54 arranges the second workpiece 62a so that the base point 71 overlaps with the base point 70. The determination unit 55 determines whether it is permitted to arrange the second workpiece 62a on the upper side of the first workpieces 61b and 61d. In this example, the difference between the height of the upper surface of the first workpiece 61b and the height of the upper surface of the first workpiece 61d exceeds the determination range R. In addition, the area where the lower surface of the second workpiece 62a faces the upper surface of the first workpiece 61d supporting the second workpiece 62a is smaller than a predetermined area. Therefore, the determination unit 55 prohibits the arrangement of the second workpiece 62a at this position. The storage unit 42 stores the position of the second workpiece 62a and the determination result.

[0127] Next, the search unit 54 moves the workpiece 62a in a predetermined direction. The search unit 54 of this embodiment moves the workpiece 62a in the same manner as the control used to search for the position of the workpiece on the first layer. In this embodiment, the workpiece 62a is moved in the X-axis direction of the workpiece coordinate system 82 and then in the Y-axis direction. As shown by the arrow 90, the search unit 54 moves the workpiece 62a in the X-axis direction of the workpiece coordinate system 82 by a predetermined small distance. The determination unit 55 determines whether it is allowed to arrange the workpiece 62a at this position. The search unit 54 repeats the movement in the X-axis direction and the determination of the arrangement of the workpiece 62a until the workpiece 62a interferes with the wall surface 60d of the container 60. The storage unit 42 stores each position of the second workpiece 62a together with the determination result.

[0128] exist Figure 22 , a top view of the workpiece and container is shown for explaining the third step in the control for arranging the second workpiece on the upper side of the first workpiece. Next, the search unit 54 moves the second workpiece 62a in the Y-axis direction from the position where the base point 71 overlaps with the base point 70, as indicated by arrow 83. The search unit 54 moves the second workpiece 62a by a small distance. The determination unit 55 determines whether the workpiece 62a can be arranged at this position. Next, the search unit 54 determines whether the workpiece 62a can be arranged while moving the second workpiece 62a in the X-axis direction by a small distance each time, as indicated by arrow 84. The search unit 54 repeats the movement in the X-axis direction and the determination of the arrangement until the second workpiece 62a interferes with the wall surface 60d. The storage unit 42 stores each position of the second workpiece 62a together with the determination result.

[0129] The second workpiece 62a is moved in the Y-axis direction until it interferes with the wall 60e of the container 60. This process of movement in the X-axis and Y-axis directions is repeated, and a control is executed to determine whether placement of the second workpiece 62a is permitted. In this example, if the second workpiece 62a is oriented such that its long side is parallel to the wall 60b, placement of the second workpiece 62a above the first workpieces 61a to 61e is prohibited.

[0130] exist Figure 23 shows a top view of the workpieces and container, illustrating the fourth step in the control for placing the second workpiece above the first workpiece. Next, the search unit 54 rotates the second workpiece 62a by a predetermined angle to change its orientation. In this embodiment, the position of the second workpiece 62a is rotated 90° about a rotation axis extending perpendicular to the bottom surface 60a of the container 60. The search unit 54 then positions the second workpiece 62a so that its corners overlap the base point 70.

[0131] In this example, the difference between the height of the upper surface of first workpiece 61b and the height of the upper surface of first workpiece 61c is within determination range R. Determination unit 55 permits placement of second workpiece 62a supported by first workpiece 61b and first workpiece 61c. Furthermore, the area of ​​the lower surface of second workpiece 62a facing first workpieces 61b and 61c is larger than a predetermined area. Therefore, determination unit 55 permits placement of workpiece 62a at this position. Storage unit 42 stores the position of workpiece 62a and the determination result.

[0132] Next, the search unit 54 repeatedly moves the workpiece coordinate system 82 in the X-axis direction, as indicated by arrow 90, and performs determination control to determine whether placement of the second workpiece 62a is permitted. Furthermore, the search unit 54 repeatedly moves in the Y-axis direction, as indicated by arrow 83, and in the X-axis direction, as indicated by arrow 84, and performs determination control to determine whether placement of the second workpiece 62a is permitted. The storage unit 42 stores all positions of the workpiece 62a and the determination results.

[0133] When the control for searching for a position where the second workpiece can be arranged above the first workpiece in this embodiment is executed, the search unit 54 may detect a plurality of positions where the second workpiece can be arranged. Figure 2 The search unit 54 of this embodiment includes a selection unit 56 for selecting a location for placing the second workpiece. The selection unit 56 sets the location for placing the second workpiece according to multiple conditions with predetermined priorities. The selection unit 56 selects the location for placing the second workpiece according to a first condition with a first priority. If there are multiple locations for placing the second workpiece that meet the first condition, the selection unit 56 selects the location for placing the second workpiece according to a second condition with a second priority. In this example, the first condition is that the height of the first workpiece supporting the second workpiece is the lowest. The second condition is that the base point of the second workpiece is closest to the base point of the container.

[0134] The selection unit 56 obtains a plurality of positions where the second workpiece is allowed to be arranged from the storage unit 42. The selection unit 56 selects the position of the second workpiece that faces the first workpiece with the lowest upper surface height from the plurality of positions where the second workpiece is allowed to be arranged according to the first condition. The selection unit 56 sets the order of the positions of the upper surfaces of the first workpieces 61a to 61e in the height direction. The search unit 54 sets the order in the order of the upper surface height from low to high. Figure 3 In the example here, the order of workpiece 61a, workpiece 61c, workpiece 61b, workpiece 61d, and workpiece 61e is set.

[0135] Reference Figure 23The second workpiece 62a can be positioned so that the short side of the planar shape of the second workpiece 62a is parallel to the wall surface 60b at a position facing the workpieces 61b and 61c, and at a position facing the workpiece 61e. The selection unit 56 selects the workpiece 61b with the lowest top surface among the workpieces 61b, 61c, and 61e. The selection unit 56 then selects a position facing the workpieces 61b and 61c. In this example, there are multiple positions where the second workpiece 62a can be positioned facing the first workpieces 61b and 61c.

[0136] Next, the selection unit 56 selects the position where the base point 71 of the second workpiece 62a is closest to the base point 70 of the container 60 according to the second condition. In this example, the position where the corner of the second workpiece 62a overlaps with the base point 70 ( Figure 23 The distance between base point 71 and base point 70 is the smallest. The selection unit 56 can set this position as the location for arranging the second workpiece 62a. In this way, by presetting the conditions with priority, the location for arranging the second workpiece can be selected.

[0137] It is also possible to determine three or more conditions for selecting the position for arranging the second workpiece. For example, as a condition other than the above for selecting the position for arranging the second workpiece, the priority of the orientation of the workpiece can be determined in advance. Figure 23 The state where the short side of the planar shape of the workpiece 62a is parallel to the wall surface 60b of the container 60 is preferred to the state where the short side of the planar shape of the workpiece 62a is parallel to the wall surface 60b of the container 60 as shown. Figure 21 As shown, the long side of the planar shape of workpiece 62a is parallel to the wall surface 60b of container 60. By predetermining the priority conditions in this way, the selection unit 56 can select the position for placing the second workpiece. This control allows the workpieces to be stacked in a manner close to the operator's desired state.

[0138] exist Figure 24 is a perspective view of the container and workpieces when a second workpiece is positioned above a first workpiece. Robot 3 positions workpiece 62a at the position determined by search unit 54. Motion control unit 43 drives robot 1 and hand 5 to position second workpiece 62a above first workpiece 61b and first workpiece 61c.

[0139] exist Figure 25 2 shows a top view of the workpieces and container, illustrating the fifth step in the control for placing the second workpiece above the first workpiece. Next, the search unit 54 searches for a position to place the second workpiece 62b. The search unit 54 performs control for setting the position to place the second workpiece 62b using the same control as for the second workpiece 62a.

[0140] The search unit 54 positions the second workpiece 62b so that its base point 71 overlaps with the base point 70 of the container. Because the second workpiece 62b interferes with the second workpiece 62a, the determination unit 55 prohibits the placement of the second workpiece 62b at this location. Next, the search unit 54 moves a small distance along the X-axis of the workpiece coordinate system 82, as indicated by arrow 90. The determination unit 55 determines whether the placement of the second workpiece 62b is permitted. This movement along the X-axis and the determination are repeated until the workpiece 62b interferes with the wall 60d of the container 60. Next, the search unit 54 repeats movement along the Y-axis and movement along the X-axis, as indicated by arrows 83 and 84, and performs the determination. This movement along the Y-axis is continued until the workpiece 62b interferes with the wall 60e of the container 60. The storage unit 42 stores all positions of the workpiece 62b and the determination results.

[0141] exist Figure 26 , a top view of the workpiece and container illustrating the sixth step in the control for arranging the second workpiece on the upper side of the first workpiece is shown. Next, the search unit 54 implements a control for determining whether the workpiece 62b can be arranged after the second workpiece 62b is rotated 90°. The search unit 54 arranges the workpiece 62b so that the corner of the workpiece 62b overlaps with the base point 70. The search unit 54 slowly moves the workpiece 62b in the X-axis direction of the workpiece coordinate system 82 as indicated by arrow 90, and determines whether the workpiece 62b can be arranged. Furthermore, the search unit 54 determines whether the workpiece 62b can be arranged while moving in the X-axis direction and the Y-axis direction as indicated by arrows 83 and 84. The storage unit 42 stores all positions of the workpiece 62b and the determination results.

[0142] exist Figure 27 , a top view of the workpiece and the container for explaining the seventh step in the control for arranging the second workpiece on the upper side of the first workpiece is shown. The selection unit 56 obtains a plurality of positions where the second workpiece 62b is allowed to be arranged from the storage unit 42. The selection unit 56 selects the position for arranging the second workpiece 62b according to predetermined conditions. In the example here, the second workpiece 62b can be arranged on the upper surface of the first workpiece 61b, 61c or the upper surface of the first workpiece 61e in a state where the short side of the second workpiece 62b is parallel to the wall surface 60b. In the example here, the second workpiece 62b is arranged in the area between the second workpiece 62a and the first workpiece 61d on the upper surface of the first workpiece 61b, 61c according to predetermined conditions.

[0143] The placement of the third and subsequent second workpieces can be performed using the same control as that used to place the second workpieces 62a and 62b. Furthermore, the placement of the second workpieces is continued until no more workpieces can be placed in the second layer within the container 60. After the placement of the second layer of workpieces is complete, the third layer of workpieces can be placed. When placing the third layer of workpieces, the same control as that used to place the second layer of workpieces can be performed. In this case, the workpiece placed in the second layer becomes the first workpiece, and the workpiece placed in the third layer becomes the second workpiece. When placing the fourth and subsequent workpieces, the same control as that used to place the third layer of workpieces can also be performed.

[0144] In this embodiment, the search unit 54 moves the second workpiece 62a to any position that does not interfere with the container 60, but this is not the only method. The range within which the second workpiece is to be moved can be predetermined. Alternatively, if a position is detected that allows placement of the second workpiece, that position can be determined as the location for placement of the second workpiece.

[0145] The time for terminating the stacking of workpieces in this embodiment can be determined by arbitrary control. For example, the control for stacking the workpieces can be terminated when the position of the highest upper surface among the upper surfaces of a plurality of workpieces exceeds a predetermined judgment value. In addition, a lid is sometimes arranged at the opening of the container. In this case, the control for stacking the workpieces can be terminated when it is determined that the upper surface of the workpiece exceeds the height of the wall surface of the container. Alternatively, when stacking workpieces on a pallet, a configuration area for configuring the workpieces on the upper side of the pallet can be pre-set. The control for stacking the workpieces can also be terminated when it is determined that the upper surface of the workpiece exceeds the configuration area. Alternatively, the configuration of the workpieces can be terminated when an instruction to terminate the control for stacking the workpieces is input by the operator through the operation of the teaching operating panel, etc.

[0146] Furthermore, the robot device can also stack workpieces in an area higher than the upper end of the container wall. In this embodiment, information about the three-dimensional shape of the container is pre-stored in the storage unit. Therefore, in an area higher than the upper end of the container wall, the workpieces can be arranged so that they overflow to the sides of the wall.

[0147] Alternatively, even if the search unit 54 finds a location for the second workpiece, there may be no location for the second workpiece above the first workpiece. In other words, the determination unit 55 may prohibit the placement of the second workpiece at all locations relative to the first workpiece. In this case, the search unit 54 sends a message to the teaching operation panel 49 indicating that no location exists for the second workpiece. The display unit 49b of the teaching operation panel 49 displays this message, allowing the operator to recognize that the stacking of the workpieces is complete. The control device 2 then terminates control of stacking the workpieces in the current container.

[0148] The position setting device of this embodiment can automatically set the position of workpieces placed in a container. Therefore, a robotic device equipped with the position setting device of this embodiment can automatically perform workpiece stacking operations. In particular, even when the number of workpieces, their sizes, and the order in which they are to be stacked have not yet been determined, the workpieces can be automatically stacked on a support member such as a container.

[0149] The sensor in this embodiment is a three-dimensional sensor that can detect the three-dimensional shape of the workpiece. Since the three-dimensional shape of the workpiece can be detected by the sensor, it is possible to eliminate the need to store information related to the shape of the workpiece in the storage unit in advance.

[0150] For example, a two-dimensional camera can be used as a sensor. Furthermore, a storage unit can pre-store a reference image related to the two-dimensional camera image. Furthermore, the storage unit can store information such as the workpiece dimensions corresponding to the reference image. The reference image that best matches the actual captured image can be selected to detect the three-dimensional shape of the workpiece. However, such control requires pre-production of the reference image of the workpiece and information such as its dimensions. Using a three-dimensional sensor as a visual sensor eliminates this requirement.

[0151] exist Figure 28 shows a top view of a workpiece for illustrating the workpiece margin width. When searching for a location to place the workpiece, search unit 54 can add a predetermined margin width MD to the dimensions of workpiece 69 to search for a location to place workpiece 69. In other words, the location to place the workpiece can be searched for using the shape of workpiece 69 obtained by adding margin width MD to its outer edge. In this case, base point 73 of workpiece 69 can be set at a corner of the shape after margin width MD is added.

[0152] Sometimes, a workpiece shakes slightly while being transported by robot 1. This shaking can cause the workpiece to interfere with other workpieces or containers. Adding a margin width to the workpiece size can reduce interference. The size of margin width MD depends on the size and weight of the workpiece and container, as well as the robot's performance. For example, margin width MD can be set to a value of 0.5 mm to 1 mm.

[0153] exist Figure 29 A stereoscopic view of another workpiece of the present embodiment is shown in FIG. The workpiece described above is a rectangular parallelepiped, but is not limited to this form. The control of the present embodiment can be applied to any workpiece having an upper surface and a lower surface. The upper surface and the lower surface can have any shape. Another workpiece 65a has an upper surface 65aa and a lower surface 65ab that are parallel to each other. The upper surface 65aa and the lower surface 65ab are planes. The shape of the upper surface 65aa and the lower surface 65ab is a pentagon. Moreover, the area of ​​the upper surface 65aa and the area of ​​the lower surface 65ab are different from each other. For such a workpiece, the same control as that of the present embodiment can also be implemented.

[0154] Furthermore, in this embodiment, the robot transports the workpiece to the position set by the position setting device, but this is not the only embodiment. Alternatively, after the position setting device sets the position for placing the workpiece, a device other than the robot may transport the workpiece. Alternatively, the display of the teaching operation panel may display the position for placing the workpiece, and the operator may place the workpiece at the displayed position.

[0155] In each of the above-mentioned controls, the order of the steps can be appropriately changed within the range in which the functions and effects are not changed.

[0156] The above embodiments can be combined as appropriate. In the above figures, the same or equivalent parts are marked with the same reference numerals. In addition, the above embodiments are illustrative and do not limit the present invention. In addition, the embodiments include changes to the embodiments shown in the claims.

[0157] Description of Reference Numerals

[0158] 1: Robot; 2: Control device; 3: Robot device; 5: Hand; 30: Visual sensor; 42: Storage unit; 49: Teaching operation panel; 49b: Display unit; 52: Shape detection unit; 53: Acquisition unit; 54: Search unit; 55: Judgment unit; 56: Selection unit; 60: Container; 61a, 61b, 61c, 61d, 61e: First workpiece; 63a~63r: First workpiece; 63aa, 63ba, 63ca, 63da, 63ea, 63fa, 63ga, 63ha: Upper surface; 62a, 62b, 62c: Second workpiece; 64a: Second workpiece; 64aa: Lower surface; 65a: Workpiece; 65aa: Upper surface; 65ab: Lower surface; 69: Workpiece; 71, 72, 73: Base point; 75: Area.

Claims

1. A position setting device for setting a position at which a second workpiece is stacked on top of a plurality of first workpieces, the position setting device comprising: a sensor for detecting a shape of a second workpiece; a shape detecting section that detects a shape of the second workpiece based on an output of the sensor; an acquisition section that acquires shapes and positions of a plurality of first workpieces; and a search unit that searches for a position where the second workpiece can be arranged above the plurality of first workpieces; in, Each of the first workpiece and the second workpiece has an upper surface and a lower surface, The determination range of the difference between the height of the upper surface of one first workpiece and the height of the upper surface of the other first workpiece is predetermined. The search unit includes a determination unit that determines whether it is permitted to arrange the second workpiece so as to be supported by both the first workpiece and the other first workpiece when the height of the upper surface of the first workpiece is different from the height of the upper surface of the other first workpiece. The determination unit allows the second workpiece to be arranged in a manner supported by both the one first workpiece and the other first workpiece when the height difference is within a determination range, and prohibits the second workpiece from being arranged in a manner supported by both the one first workpiece and the other first workpiece when the height difference exceeds the determination range. The determination unit allows the second workpiece to be arranged on the upper side of the first workpiece when the area of ​​the lower surface of the second workpiece facing the upper surface of the first workpiece arranged to support the second workpiece is larger than the area obtained by multiplying the area of ​​the lower surface of the second workpiece by a predetermined ratio. The determination unit sets a plurality of regions obtained by dividing the lower surface of the second workpiece, The determination unit allows the second workpiece to be arranged above the first workpiece when the number of regions facing the first workpiece is equal to or greater than a predetermined determination value.

2. A position setting device for setting a position at which a second workpiece is stacked on top of a plurality of first workpieces, the position setting device comprising: a sensor for detecting a shape of a second workpiece; a shape detecting section that detects a shape of the second workpiece based on an output of the sensor; an acquisition section that acquires shapes and positions of a plurality of first workpieces; and a search unit that searches for a position where the second workpiece can be arranged above the plurality of first workpieces; in, Each of the first workpiece and the second workpiece has an upper surface and a lower surface, The determination range of the difference between the height of the upper surface of one first workpiece and the height of the upper surface of the other first workpiece is predetermined. The search unit includes a determination unit that determines whether it is permitted to arrange the second workpiece so as to be supported by both the first workpiece and the other first workpiece when the height of the upper surface of the first workpiece is different from the height of the upper surface of the other first workpiece. The determination unit allows the second workpiece to be arranged in a manner supported by both the one first workpiece and the other first workpiece when the height difference is within a determination range, and prohibits the second workpiece from being arranged in a manner supported by both the one first workpiece and the other first workpiece when the height difference exceeds the determination range. The determination unit allows the second workpiece to be arranged above the first workpiece when the first workpiece arranged to support the second workpiece is arranged so as to surround the center of gravity of the shape of the lower surface of the second workpiece. The determination unit sets a plurality of regions obtained by dividing the lower surface of the second workpiece, The determination unit allows the second workpiece to be arranged above the first workpiece when a predetermined region among a plurality of regions arranged on the outer peripheral portion of the lower surface of the second workpiece faces the first workpiece.

3. A position setting device for setting a position at which a second workpiece is stacked on top of a plurality of first workpieces, the position setting device comprising: a sensor for detecting a shape of a second workpiece; a shape detecting section that detects a shape of the second workpiece based on an output of the sensor; an acquisition section that acquires shapes and positions of a plurality of first workpieces; and a search unit that searches for a position where the second workpiece can be arranged above the plurality of first workpieces; in, Each of the first workpiece and the second workpiece has an upper surface and a lower surface, The determination range of the difference between the height of the upper surface of one first workpiece and the height of the upper surface of the other first workpiece is predetermined. The search unit includes a determination unit that determines whether it is permitted to arrange the second workpiece so as to be supported by both the first workpiece and the other first workpiece when the height of the upper surface of the first workpiece is different from the height of the upper surface of the other first workpiece. The determination unit allows the second workpiece to be arranged in a manner supported by both the one first workpiece and the other first workpiece when the height difference is within a determination range, and prohibits the second workpiece from being arranged in a manner supported by both the one first workpiece and the other first workpiece when the height difference exceeds the determination range. The search unit includes a selection unit that selects a position for arranging the second workpiece when a plurality of positions above the first workpiece are allowed to be arranged. The selecting unit selects a position for arranging the second workpiece according to a first condition having a first priority. When there are a plurality of positions for arranging the second workpiece that satisfy the first condition, the selecting unit selects the position for arranging the second workpiece according to a second condition having a second priority.

4. The position setting device according to any one of claims 1 to 3, wherein: The sensor is a three-dimensional sensor capable of detecting a three-dimensional shape of the first workpiece.

5. The position setting device according to any one of claims 1 to 3, wherein: The position setting device further includes a display unit for displaying information related to the arrangement of the second workpiece. When the search unit cannot detect a position above the first workpiece where the second workpiece can be arranged, the display unit displays that there is no position where the second workpiece can be arranged.

6. The position setting device according to any one of claims 1 to 3, wherein: The determination unit adds a predetermined margin width to the size of the second workpiece to determine whether placement of the second workpiece is permitted.

7. A robotic device comprising: The position setting device according to any one of claims 1 to 3; a working tool for holding a second workpiece; a robot for moving the work tool; and a control device for controlling the working tool and the robot, in, The control device detects the position and posture of the second workpiece based on the output of the sensor, drives the robot to grasp the second workpiece based on the position and posture of the second workpiece, and drives the robot to transport the second workpiece to the position for configuring the second workpiece set by the position setting device.

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