Gripping device, gripping robot, and gripping method

Abstract

To provide a holding device which can hold a box without moving the box laterally, and to provide a holding robot and a holding method.SOLUTION: A holding device 10 according to the disclosure may move while holding a box B1. In the box B1, a first side wall B1a and a second side wall B1b are connected; the first side wall B1a and a third side wall B1c face each other; and the second side wall B1b and a fourth side wall B1d face each other. The holding device 10 includes: a first holding part which sandwiches an inner wall surface and an outer wall surface of the first side wall B1a to hold the first side wall B1a; a second holding part which sandwiches an inner wall surface and an outer wall surface of the second side wall B1b to hold the second side wall B1b; and a first assist holding part which presses against an outer wall surface of the third side wall B1c to assist holding of the box B1 after the holding device 10 moves upward with the first holding part holding the first side wall B1a and the second holding part holding the second side wall B1b.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to a gripping device, a gripping robot, and a gripping method.

Background Art

[0002] The picking device disclosed in Patent Document 1 lifts a container. Specifically, the container includes a first side wall, a second side wall, a first edge, and a second edge. The second side wall faces the first side wall. The first edge extends outward from the upper end of the first side wall. The second edge extends outward from the upper end of the second side wall. More specifically, the picking device disclosed in Patent Document 1 first engages a fixed claw with the first edge of the container, then lifts it and moves it horizontally for a certain distance. Thereafter, the device moves a moving claw and engages it with the second edge of the container to lift the container.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present application have discovered the following problems. Such a picking device grips the opposing first and second side walls to lift the container. Therefore, when one of the first and second side walls of the container is in close contact with the side wall of another container, it is necessary to move the container horizontally.

[0005] This disclosure has been made in view of the above problems, and provides a gripping device, a gripping robot, and a gripping method that can grip a box without moving it horizontally.

Means for Solving the Problems

[0006] The gripping device relating to this disclosure is In a gripping device that can move while gripping a box, The box comprises first, second, third, and fourth side walls, The first and second side walls are connected, The first and third side walls face each other, The second and fourth side walls are opposite each other, A first gripping portion (for example, a first main claw 1, etc.) that grips the first side wall by sandwiching the inner wall surface and the outer wall surface of the first side wall, A second gripping portion (for example, a second main claw 2, etc.) that grips the second side wall by sandwiching the inner wall surface and the outer wall surface of the second side wall, The gripping device includes a first auxiliary gripping part (for example, a first auxiliary claw 3, etc.) that, while the first gripping part grips the first side wall and the second gripping part grips the second side wall, moves upward and then presses against the outer wall surface of the third side wall to assist in gripping the box.

[0007] Furthermore, the gripping device described above may also include a second auxiliary gripping part (for example, a second auxiliary claw 4, etc.) that, while the first gripping part grips the first side wall and the second gripping part grips the second side wall, moves upward and then presses against the outer wall surface of the fourth side wall to assist in gripping the box.

[0008] Furthermore, in the gripping device described above, the first gripping portion comprises an outer claw and an inner claw, The first gripping portion grips the first side wall by pressing the outer claw against the outer wall surface of the first side wall and the inner claw against the inner wall surface of the first side wall, thereby sandwiching the inner and outer wall surfaces of the first side wall. The length in the height direction of the portion that contacts the inner claw with the first side wall should be less than or equal to the stacking allowance.

[0009] The gripping robot related to this disclosure is A gripping robot equipped with the gripping device described above, The arm to which the gripping device is attached, The system includes a control unit that moves the gripping device by extending or bending the arm.

[0010] The gripping method relating to this disclosure is: A gripping method for gripping a box using a gripping device of a gripping robot equipped with a first auxiliary gripping unit, The box comprises first, second, third, and fourth side walls, The first and second side walls are connected, The first and third side walls face each other, The second and fourth side walls are opposite each other, The steps include gripping the first side wall by sandwiching the inner wall surface and the outer wall surface of the first side wall, The steps include gripping the second side wall by sandwiching its inner and outer wall surfaces, The method includes the step of moving the box upward while gripping the first side wall and the second side wall, and then pressing the first auxiliary gripping part against the outer wall surface of the third side wall to assist in gripping the box. [Effects of the Invention]

[0011] According to this disclosure, the box can be gripped without moving it laterally. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing one configuration of a gripping robot according to Embodiment 1. [Figure 2] This is a schematic diagram showing one example configuration of a gripping device according to Embodiment 1. [Figure 3] This is a flowchart showing the gripping method according to Embodiment 1. [Figure 4] This is a perspective view showing one example configuration of two stacked boxes. [Figure 5] This is a schematic diagram showing a cross-section of one example configuration of two stacked boxes at the cutting line IV-IV. [Figure 6]It is a schematic diagram showing a part of the gripping method according to Embodiment 1. [Figure 7] It is a schematic diagram showing a part of the gripping method according to Embodiment 1. [Figure 8] It is a schematic diagram showing a part of the gripping method according to Embodiment 1.

Embodiments for Carrying out the Invention

[0013] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are appropriately simplified.

[0014] <Embodiment 1> Embodiment 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing a configuration of a gripping robot according to Embodiment 1. FIG. 2 is a schematic diagram showing an example of a configuration of a gripping device of the gripping robot shown in FIG. 1.

[0015] Of course, the right-handed XYZ coordinates shown in FIG. 1 and other drawings are for convenience in explaining the positional relationship of the components. Usually, the positive Z-axis direction is vertically upward, the XY plane is a horizontal plane, and they are common among the drawings.

[0016] As shown in FIG. 1, the gripping robot 100 includes a gripping device 10, a control device 30, and an arm 40. The gripping robot 100 may further include an image processing device 20.

[0017] The image processing device 20 is positioned to capture images of the box group BB from above. The box group BB is held on a pallet PP placed on the ground GS or the like. The box group BB includes multiple boxes B1, B2, B3, B4, etc. The number of boxes B1, etc. that make up the box group BB is not particularly limited. The multiple boxes B1, B2, B3, B4, etc. may be stacked in a roughly rectangular parallelepiped or roughly cubic shape, for example. The multiple boxes B1, B2, B3, B4, etc. may have the same configuration. The image processing device 20 detects the position of a predetermined box from the image captured of the box group BB. The predetermined box is one of the multiple boxes B1, B2, B3, B4, etc. The image processing device 20 may be positioned above the box group BB, on the gripping device 10, or on the arm 40.

[0018] The control device 30 acquires the position of a predetermined box detected by the image processing device 20. The control device 30 may also acquire an image of the box group BB taken from above. Based on this acquired image, the control device 30 controls the operation of the arm 40 and the gripping device 10. The control device 30 may also acquire the starting position and ending position of the gripping device 10.

[0019] The arm 40 comprises, for example, a main body 41, members 42, 44, and 46, joints 43, 45, and 47, and a hand 48. Member 42 is supported by the main body 41. Member 44 is rotatably connected to member 42 via joint 43. Member 46 is rotatably connected to member 44 via joint 45. Hand 48 is rotatably connected to member 46 via joint 47. Hand 48 includes a gripping device 10. The arm 40 can freely translate or rotate the box B1 in a predetermined three-dimensional space and change its orientation to face a predetermined direction, as described above, by the rotation of the hand 48 and members 42, 44, and 46 while the gripping device 10 grips the box B1 or the like.

[0020] As shown in Figures 1 and 2, the gripping device 10 comprises a main body 10a, a first main claw 1, a second main claw 2, and a first auxiliary claw 3. The gripping device 10 may further include a second auxiliary claw 4. The gripping device 10 can be freely translated or rotated within a predetermined three-dimensional space and change its orientation to face a predetermined direction, for example, by an arm 40.

[0021] The main body 10a holds the first main claw 1 and the second main claw 2 in a manner that allows them to grip. The main body 10a also holds the first auxiliary claw 3 and the second auxiliary claw 4 in a manner that allows them to move. The main body 10a may be equipped with a drive source such as a motor as appropriate for gripping the first main claw 1 and the second main claw 2 and for moving the first auxiliary claw 3 and the second auxiliary claw 4.

[0022] The first main claw 1 comprises an outer claw 1a and an inner claw 1b. The outer claw 1a and the inner claw 1b are held so as to be able to move toward and away from each other. The first main claw 1 grips an object by having the outer claw 1a and the inner claw 1b grip the object.

[0023] The second main claw 2 comprises an outer claw 2a and an inner claw 2b. The outer claw 2a and the inner claw 2b are held so as to be able to move closer to and further apart from each other. The second main claw 2 grips an object by having the outer claw 2a and the inner claw 2b grip the object.

[0024] The first auxiliary claw 3 is held so as to be able to approach the first main claw 1 and to be able to move away from the first main claw 1. The first auxiliary claw 3 presses against the object to be gripped and assists in the gripping by the first main claw 1.

[0025] The second auxiliary claw 4 is held so as to be able to approach the second main claw 2 and to be able to move away from the second main claw 2. The second auxiliary claw 4 presses against the object to be gripped, assisting the gripping by the second main claw 2.

[0026] <Gripping method> Next, with reference to Figures 3 to 8, an example of a gripping method for gripping box B1 using the gripping device 10 of the gripping robot 100 will be described. This example of a gripping method is performed in the method of transferring box B1.

[0027] The object to be gripped by this gripping method is box B1 shown in Figure 4. Box B1 is capable of holding luggage. Box B1 comprises a first side wall B1a, a second side wall B1b, a third side wall B1c, a fourth side wall B1d, and a bottom B1e. The first side wall B1a and the second side wall B1b are connected. Furthermore, the first side wall B1a and the second side wall B1b intersect, and the angle formed by the intersection of the first side wall B1a and the second side wall B1b is preferably approximately a right angle. The first side wall B1a and the third side wall B1c face each other. The first side wall B1a and the fourth side wall B1d face each other. The bottom B1e is, for example, a roughly rectangular plate shape. The first side wall B1a, the second side wall B1b, the third side wall B1c, and the fourth side wall B1d are preferably provided so as to rise from the outer edge of the bottom B1e. The top of the box B1 is open. This opening is formed from the upper end of the first side wall B1a, the upper end of the second side wall B1b, the upper end of the third side wall B1c, and the upper end of the fourth side wall B1d.

[0028] Box B1 may have at least one edge B1f, rib B1g, projection B1h, and protrusion B1i. The first side wall B1a, second side wall B1b, third side wall B1c, and fourth side wall B1d of box B1 shown in Figure 4 are provided with an edge B1f, rib B1g, and projection B1h. In addition, the bottom B1e of box B1 shown in Figure 4 is provided with a protrusion B1i.

[0029] Box B1 is placed on top of box B4. Box B4 has the same configuration as box B1. As shown in Figure 5, box B4 holds the cargo LL. The first side wall B4a of box B4 holds the lower part of the first side wall B1a of box B1, and maintains a predetermined distance between the bottom B1e of box B1 and the bottom B4e of box B4. This prevents the bottom B1e of box B1 from mechanically interfering with the cargo LL. The height from the lower bottom surface of the bottom B1e of box B1 to the upper end of the first side wall B4a is set as the stacking allowance LM. Furthermore, it is preferable that the inner wall surface of the first side wall B4a is separated from the outer surface of the cargo LL. Specifically, it is preferable that the distance LD between the inner wall surface of the first side wall B4a and the outer surface of the cargo LL is defined.

[0030] First, the position of box B1 is detected (step ST1). Specifically, the image processing device 20 generates an image of the box group BB taken from above. The image processing device 20 detects the position of box B1 from this captured image.

[0031] Next, the gripping device 10 is moved to the position of box B1 (step ST2). Based on the detected position of box B1, the control device 30 operates the arm 40 to move the gripping device 10. The control device 30 should move the gripping device 10 to a position where it can grip box B1. As shown in Figure 6, box B1 is preferably located in the uppermost row and in one of the four corners of the box group BB. The first side wall B1a and the second side wall B1b are not in close contact with other boxes and are exposed from the box group BB. The third side wall B1c and the fourth side wall B1d are in close contact with other boxes B2 and B21, respectively.

[0032] Next, the box B1 is grasped using the first main claw 1 and the second main claw 2 (step ST3).

[0033] By pressing the outer claw 1a against the outer wall surface of the first side wall B1a and the inner claw 1b against the inner wall surface of the first side wall B1a, the inner and outer wall surfaces of the first side wall B1a are clamped together. As a result, the first main claw 1 grips the first side wall B1a.

[0034] Similarly, by pressing the outer claw 2a against the outer wall surface of the second side wall B1b and the inner claw 2b against the inner wall surface of the second side wall B1b, the inner and outer wall surfaces of the second side wall B1b are clamped together. As a result, the second main claw 2 grips the second side wall B1b.

[0035] Next, box B1 is lifted (step ST4). As shown in Figure 7, the gripping device 10 is moved upward while the first main claw 1 grips the first side wall B1a and the second main claw 2 grips the second side wall B1b. Box B1 moves upward together with the gripping device 10. The amount of movement LB1 of box B1 should be, for example, greater than or equal to the height length L3 of the part where the first auxiliary claw 3 and the third side wall B1c come into contact. Also, the amount of movement LB1 of box B1 should be greater than or equal to the height length L4 (not shown) of the part where the second auxiliary claw 4 and the fourth side wall B1d come into contact. Box B1 moves upward together with the gripping device 10. In step ST6, which will be described later, the first auxiliary claw 3 and the second auxiliary claw 4 can be easily assisted in gripping.

[0036] Furthermore, the thickness LT of the inner claw 1b should be less than or equal to the distance LD between the inner wall surface of the first side wall B4a and the outer surface of the cargo LL, as shown in Figure 5. The height length LH of the portion in contact between the inner claw 1b and the first side wall B1a should be less than or equal to the stacking allowance LM, as shown in Figure 5. In this way, if the thickness LT and length LH of the inner claw 1b are limited to a predetermined range, mechanical interference between the inner claw 1b and the cargo LL can be suppressed when the box B1 holds the cargo LL. Similarly, the thickness and length of the inner claw 2b should be limited to a predetermined range.

[0037] Next, the first auxiliary claw 3 and the second auxiliary claw 4 are moved (step ST5). Specifically, the control device 30 operates the gripping device 10 based on the detected position of the box B1, moving the first auxiliary claw 3 and the second auxiliary claw 4. More specifically, the control device 30 moves the first auxiliary claw 3 to the vicinity of the third side wall B1c and the second auxiliary claw 4 to the vicinity of the fourth side wall B1d.

[0038] Next, the first auxiliary claw 3 and the second auxiliary claw 4 are used to assist in holding the box B1 (step ST6). As shown in Figure 8, the first auxiliary claw 3 is pressed against the outer wall surface of the third side wall B1c. This allows the first auxiliary claw 3 to assist in gripping the box B1. The second auxiliary claw 4 is pressed against the outer wall surface of the fourth side wall B1d. This allows the first auxiliary claw 3 to assist in gripping the box B1.

[0039] Next, box B1 is moved to the desired position (step ST7). The control device 30 operates the arm 40 based on the desired position and moves the gripping device 10. When the control device 30 rotates the gripping device 10, the first auxiliary claw 3 and the second auxiliary claw 4 assist in holding box B1, so the gripping device 10 can firmly hold box B1. Also, box B1 moves to the desired position together with the gripping device 10. The gripping device 10 releases its grip on box B1 and places box B1 in the desired position.

[0040] Next, determine whether all boxes to be moved have been moved (Step ST8). If all boxes to be moved have been moved (Step ST8: YES), the process of moving box B1 is terminated. If not all boxes to be moved have been moved (Step ST8: NO), return to Step ST1.

[0041] As described above, box B1 can be gripped without moving it laterally. Since there is no need to move box B1 laterally, the transfer operation can be made faster. Furthermore, after lifting box B1, the first auxiliary claw 3 and the second auxiliary claw 4 are used to assist in holding box B1. This prevents mechanical interference between the first auxiliary claw 3 and other boxes B21. It also prevents mechanical interference between the second auxiliary claw 4 and other boxes B2.

[0042] The control device 30 in the above-described embodiment is composed of hardware, software, or both, and may consist of one piece of hardware or software, or multiple pieces of hardware or software. The functions (processing) of each device may be realized by a computer having a CPU (Central Processing Unit), memory, etc. For example, a program for performing the method in the embodiment (e.g., control method) may be stored in a storage device, and each function may be realized by executing the program stored in the storage device with the CPU.

[0043] These programs can be stored and supplied to a computer using various types of non-transitory computer-readable medium. Non-transitory computer-readable medium includes various types of tangible storage medium. Examples of non-transitory computer-readable medium include magnetic storage media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical storage media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memory (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, RAMs (random access memory)). Programs may also be supplied to a computer using various types of transient computer-readable medium. Examples of transient computer-readable medium include electrical signals, optical signals, and electromagnetic waves. Transitory computer-readable medium can be supplied to a computer via wired communication channels such as electric wires and optical fibers, or via wireless communication channels.

[0044] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. Furthermore, the present invention may be implemented by appropriately combining the above embodiments or examples thereof. For example, although the gripping method according to this embodiment was performed in a method for transferring box B1, it may also be performed in a method for forming a group of boxes by stacking multiple boxes. In the method for forming a group of boxes by stacking multiple boxes, for example, steps ST2 to ST7 may be performed in reverse order and repeated. Specifically, first, box B1 is moved above the position where it is to be stacked. Next, the gripping assistance of box B1 using the first auxiliary claw 3 and the second auxiliary claw 4 is released. That is, the first auxiliary claw 3 is separated from the outer wall surface of the third side wall B1c. The second auxiliary claw 4 is separated from the outer wall surface of the fourth side wall B1d. Next, box B1 is lowered to the position where it is to be stacked. Box B1 is placed at the position where it is to be stacked. Next, the gripping of box B1 using the first main claw 1 and the second main claw 2 is released. That is, the outer claw 1a is separated from the outer wall surface of the first side wall B1a, and the inner claw 1b is separated from the inner wall surface of the first side wall B1a. Similarly, the outer claw 2a is separated from the outer wall surface of the second side wall B1b, and the inner claw 2b is separated from the inner wall surface of the second side wall B1b. Finally, the gripping device 10 is separated from box B1. Similarly, other boxes B2, B3, B4, etc. are stacked. In this way, a box group BB can be formed. Alternatively, if there are different types of boxes, a box group can be formed for each type using the method of forming a box group by stacking multiple boxes. This allows for the formation of multiple box groups consisting of one type of box without moving the boxes laterally, thus enabling box sorting in a short time. [Explanation of symbols]

[0045] 10 Gripping device 1. First main claw 1a Outer nail 1b Inner claw 2. Second main claw 2a Outside claw 2b Inner claw 3. First auxiliary claw 4. Second auxiliary claw 100 Grasping Robots 20 Image Processing Devices 30 Control device 40 Arms 41 Main unit Members 42, 44, and 46 43, 45, 47 Joints 48 Hand BB box group B1, B2, B3, B4, B21 box B1a First side wall B1b Second side wall B1c Third side wall B1d Fourth side wall B1e bottom B1F Edge B1g Rib B1h protrusion B1i protrusion PP pallet GS ground L3 Length LB1 travel amount LD distance LM stacking amount LT thickness

Claims

1. In a gripping device that can move while gripping a box, The box comprises first, second, third, and fourth side walls, The first and second side walls are connected, The first and third side walls are opposite each other, The second and fourth side walls face each other, A first gripping portion that grips the first side wall by sandwiching the inner wall surface and the outer wall surface of the first side wall, A second gripping portion that grips the second side wall by sandwiching the inner wall surface and the outer wall surface of the second side wall, A first auxiliary gripping portion is movable to approach and move away from the first gripping portion, and after the gripping device moves upward while the first gripping portion grips the first side wall and the second gripping portion grips the second side wall, it presses against only the outer wall surface of the third side wall to assist the gripping of the box by the first gripping portion, The gripping device includes a second auxiliary gripping portion which is movable toward and away from the second gripping portion, and which, after the gripping device moves upward while the first gripping portion grips the first side wall and the second gripping portion continues to grip the second side wall, presses against only the outer wall surface of the fourth side wall to assist the gripping of the box by the second gripping portion, gripping device.

2. The first gripping portion comprises an outer claw and an inner claw, The first gripping portion grips the first side wall by pressing the outer claw against the outer wall surface of the first side wall and the inner claw against the inner wall surface of the first side wall, thereby sandwiching the inner and outer wall surfaces of the first side wall. The height of the portion in contact between the inner claw and the first side wall is less than or equal to the stacking allowance. The gripping device according to claim 1.

3. A gripping robot equipped with the gripping device described in claim 1 or 2, The arm to which the gripping device is attached, A gripping robot comprising a control unit that moves the gripping device by extending or bending the arm.

4. A gripping method for gripping a box using a gripping device of a gripping robot equipped with a first auxiliary gripping part and a second auxiliary gripping part, The box comprises first, second, third, and fourth side walls, The first and second side walls are connected, The first and third side walls are opposite each other, The second and fourth side walls face each other, The first step is to grip the first side wall by sandwiching the inner wall surface and the outer wall surface of the first side wall with the first gripping portion, The steps include gripping the second side wall by sandwiching the inner and outer wall surfaces of the second side wall with the second gripping portion, The steps include: moving the box upward while gripping the first side wall and the second side wall, then pressing the first auxiliary gripping part, which can approach and move away from the first gripping part, against only the outer wall surface of the third side wall to assist the gripping of the box by the first gripping part; The steps include: moving the box upward while gripping the first side wall and maintaining gripping the second side wall, then pressing the second auxiliary gripping part, which is able to approach and move away from the second gripping part, only against the outer wall surface of the fourth side wall to assist the gripping of the box by the second gripping part; Equipped with, Grasping method.

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