Gripping device, and gripping method

Abstract

To stably grip workpiece of magnetic bodies having various shapes.SOLUTION: A gripping device 10 includes: a bag body 14 which is brought into contact with workpiece W as a magnetic body, and has such flexibility and air tightness as to store a granule 15; a suction / exhaust part 16 for exhausting gas from the bag body 14 or supplying the gas to the bag body 14, and thereby deforming the bag body 14 in accordance with the shape of the workpiece W, when the bag body 14 is brought into contact with the workpiece W; and a magnet 12 for acting magnet force on the workpiece W, and gripping the workpiece W in a state in which the bag body 14 is deformed in accordance with the shape of the workpiece W.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gripping device and a gripping method. [Background technology]

[0002] As an end effector of an industrial robot, there is a gripping device called a gripper that is used to grip an object. Patent Document 1 discloses a magnetic gripper that holds a magnetic workpiece by magnetic force. The magnetic gripper in Patent Document 1 is a permanent magnet type magnetic gripper that can be switched between a holding state in which the workpiece is held by magnetic force and a release state in which the grip is released.

[0003] In Patent Document 1, a permanent magnet is disposed in a housing made of a non-magnetic material that is open at the bottom, and is movable in the vertical direction with its magnetized surface facing downward. The opening of the housing is formed in an inclined shape. This magnetic gripper is in a holding state when the entire magnetized surface of the permanent magnet protrudes from the opening of the housing, and in a released state when at least a part of the magnetized surface is retracted inside the housing. Patent Document 2 discloses a gripping device that presses a bag against an object placed on a support surface to grip it. In Patent Document 2, a deformable bag is pressed against the object, and powder or granular material is introduced into the bag to expand the bag and reduce the gap between the bag and the object, and only the gas of the powder or granular material and gas inside the bag is sucked and discharged to the outside of the bag. This increases the friction between the powder or granular material inside the bag, and the shape of the bag is maintained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-155534 A [Patent Document 2] JP 2013-220492 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the downward magnetized surface of the permanent magnet becomes the gripping surface that grips the workpiece. If the shape of the workpiece and the shape of the gripping surface do not match well, the gripper may not be able to grip the workpiece. In particular, if rotation occurs between the gripping surface and the workpiece, it becomes more difficult for the gripper to grip the workpiece.

[0006] When replacing the gripper according to the shape and posture of the object to be gripped, the work of selecting an appropriate gripper and the work of replacing the gripper are required. In addition, complex calculations are required for planning the gripping of the object to be gripped by the selected gripper and estimating the posture of the workpiece from the start of gripping to the end. It is assumed that an industrial robot equipped with such a gripper operates by performing, for example, machine learning. Such work related to gripper replacement may lead to a decrease in the efficiency of the gripping work by the robot. In addition, in Patent Document 2, it is necessary to reduce the gap between the bag body and the object to an extent that the object can be gripped, and there is a problem that the object is limited.

[0007] The present invention has been made in consideration of such problems, and an object of the present invention is to stably grip magnetic workpieces of various shapes. [Means for solving the problem]

[0008] A gripping device according to one embodiment of the present invention comprises a flexible and airtight bag body for containing powdered material and for contacting a workpiece which is a magnetic material; an intake and exhaust section for deforming the bag body to conform to the shape of the workpiece when the bag body comes into contact with the workpiece by discharging gas from the bag body or supplying gas to the bag body; and a magnetic attraction section for applying a magnetic force to the workpiece to grip the workpiece while the bag body is deformed to conform to the shape of the workpiece.

[0009] A gripping method according to one embodiment of the present invention includes a step of deforming a flexible and airtight bag body containing powder or granular material to conform to the shape of the workpiece when the bag body comes into contact with the workpiece, by discharging gas from or supplying gas to the bag body, which is in contact with the workpiece, and a step of applying a magnetic force to the workpiece while the bag body is deformed to conform to the shape of the workpiece to grip the workpiece. Effect of the Invention

[0010] According to the present invention, it is possible to stably grip magnetic workpieces of various shapes. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a gripping device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram for explaining a gripping method according to the first embodiment. [Diagram 3] FIG. 11 is a schematic diagram showing the configuration of a gripping device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the numerical values, shapes, materials, components, arrangement positions of the components, steps, and order of steps shown in the following embodiments are merely examples and do not limit the present disclosure.

[0013] In addition, since the drawings are simplified, the technical scope of the present disclosure should not be interpreted narrowly based on the description in the drawings. Please note that the drawings are not drawn to actual scale for convenience of explanation. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted.

[0014] Embodiment 1. Fig. 1 is a schematic diagram showing the configuration of a gripping device 10 according to embodiment 1. As shown in Fig. 1, the gripping device 10 includes a housing 11, a magnet 12, an air cylinder 13, a bag body 14, powder and granular material 15, and an intake and exhaust unit 16. The gripping device 10 is a magnetic gripper that can be switched between a gripping state in which a workpiece W, which is a magnetic material, is gripped by magnetic force and a release state in which the gripping is released.

[0015] 1, the housing 11 is a hollow rectangular parallelepiped. An opening is provided at the lower end of the housing 11. The housing 11 is made of a non-magnetic material. Examples of materials for the housing 11 include stainless steel, copper, and aluminum. The housing 11 may also be made of resin or ceramic.

[0016] A magnet 12 is disposed within the housing 11. The magnet 12 may include a permanent magnet such as a ferrite magnet or a neodymium magnet. The magnet 12 may be an electromagnet capable of electrically controlling the generation of magnetic force.

[0017] The magnet 12 is movable in the vertical direction within the housing 11. In the example shown in FIG. 1, an air cylinder 13 is provided on the upper part of the housing 11, and the air cylinder 13 moves the magnet 12 in the vertical direction within the housing 11. The magnet 12 and the air cylinder 13 correspond to the magnetic attraction unit described in the claims. The air cylinder 13 functions as a switching unit that brings the magnet 12 close to the workpiece W within the housing 11 to a gripping state, and moves the magnet 12 away from the workpiece W to a released state. Note that the mechanism for moving the magnet 12 may be another mechanism, such as an electric actuator equipped with a motor.

[0018] As an example, the air cylinder 13 can be in a gripping state by making the magnet 12 protrude from the opening of the housing 11, and in a released state by making the magnet 12 retract into the housing 11. Note that, as in Patent Document 1, the lower end of the housing 11 may have an inclined opening. As a result, between the state in which the magnet 12 protrudes from the housing 11 and the state in which the magnet 12 retracts into the housing 11, a state in which the magnet 12 partially protrudes from and partially retracts into the housing 11 is provided. With this configuration, the grip of the workpiece W by the magnet 12 is released in stages.

[0019] A bag 14 containing powdered or granular material 15 is provided at the lower end of the housing 11. The bag 14 is a portion of the gripping device 10 that grips the workpiece W. The bag 14 is flexible and airtight, and has a space inside. The bag 14 is made of an elastically deformable material such as rubber or silicone rubber. Note that the bag 14 is not limited to being elastically deformable, as long as it can be reversibly deformed in shape by an external force. Also, a material with high gas barrier properties may be used to prevent gas from escaping from the bag 14.

[0020] Powder and granular material 15 is contained within the space of the bag body 14. The powder and granular material 15 filled in the bag body 14 behaves like a solid or like a fluid due to jamming transition, so that the bag body 14 goes into a hardened state in which it is difficult to deform, or into a softened state in which it is deformable.

[0021] An intake and exhaust unit 16 is connected to the bag body 14. For example, a vacuum pump or the like can be used as the intake and exhaust unit 16. The intake and exhaust unit 16 reduces the pressure inside the bag body 14 by discharging gas from inside the bag body 14, and pressurizes the inside of the bag body 14 by supplying gas into the bag body 14. The bag body 14 and the intake and exhaust unit 16 may be connected by a cylindrical pipe made of metal or resin, or the like.

[0022] The intake and exhaust section 16 reduces the pressure inside the bag body 14 to a predetermined negative pressure by discharging gas (air) from the bag body 14, and causes the powder and granular materials 15 inside the bag body 14 to adhere to each other. In this way, the gaps between the powder and granular materials 15 are reduced, and the powder and granular materials 15 cannot move. As a result, the powder and granular materials 15 are solidified, and the bag body 14 enters a hardened state in which it is less likely to deform.

[0023] The intake and exhaust unit 16 also supplies gas to the bag body 14 to return the pressure inside the bag body 14 to, for example, atmospheric pressure, and creates gaps between the powder and granular material 15 inside the bag body 14. By forming gaps between the powder and granular material 15 in this way, the powder and granular material 15 can move more easily inside the bag body 14. This causes the powder and granular material 15 to become fluid, and the bag body 14 enters a softened state in which it is more easily deformed. In other words, the intake and exhaust unit 16 controls the intake and exhaust of the bag body 14, so that the bag body 14 can be switched between a hardened state and a softened state.

[0024] The powder or granular material 15 is one that flows easily when the shape of the bag body 14 is deformed to match the shape of the workpiece W. The shape of the powder or granular material 15 is not particularly limited, and it may be spherical, polygonal, or have a jagged uneven shape. The size of the powder or granular material 15 may be such that it is not discharged together with the gas discharged from the bag body 14. The size of the powder or granular material 15 may be, for example, about 3 mm to 10 mm in diameter.

[0025] A filter may be provided between the bag 14 and the intake / exhaust section 16. The filter prevents the powder / granular material 15 from entering the intake / exhaust section 16. Such a filter has, for example, a mesh structure smaller than the diameter of the powder / granular material 15.

[0026] The powdered material 15 may be a non-magnetic powder. In this case, zirconia balls, resin beads, glass beads, etc. may be used as the powdered material 15. Coffee bean powder may also be used as the powdered material 15. The powdered material 15 may also be a magnetic powder. In this case, iron balls or the like are used as the powdered material 15. When magnetic powder is used as the powdered material 15, the powdered material 15 can be magnetized by the magnetic field of the magnet 12. In this way, the magnet 12 can apply a magnetic force to the workpiece W through the powdered material 15. The material of the powdered material 15 is not limited to the above example, and may be any material that is filled in the bag body 14 and exhibits jamming transition.

[0027] 2 is a diagram for explaining the gripping method according to the first embodiment. As an example, first, the bag body 14 in a softened state is pressed against the workpiece W. Then, the intake and exhaust unit 16 exhausts the gas inside the bag body 14, thereby changing the shape of the bag body 14 to match the shape of the workpiece. Thereafter, in a state in which the bag body 14 has been deformed to a shape following the shape of the workpiece W, the magnet 12 is moved so as to approach the workpiece W, and a magnetic force is applied to the workpiece W to grip the workpiece W.

[0028] Fig. 2 shows a state in which the workpiece W, which is a magnetic body, is gripped by the magnetic force of the magnet 12. As shown in Fig. 2, the bag body 14 in a hardened state has a shape that imitates the shape of the workpiece W. When the workpiece W is gripped by the magnet 12 in this state in which the shape of the workpiece W matches the shape of the bag body 14, the workpiece W can be held stably without rotating on the gripping surface.

[0029] Furthermore, when the shape or posture of the workpiece W is different, the bag body 14 can be deformed into a different shape by the intake and exhaust unit 16 controlling the intake and exhaust of the bag body 14. This makes it possible to suppress a decrease in work efficiency caused by the gripper replacement work.

[0030] Embodiment 2. Fig. 3 is a schematic diagram showing the configuration of a gripping device 10A according to embodiment 2. The second embodiment is different from the first embodiment in that two bags 14A and 14B each containing powder or granular material 15 are provided. In the example shown in Fig. 3, the bag body 14A and the bag body 14B are arranged side by side on the opening side of one housing 11. The number of the bags 14 is not limited to this example. Also, the bag body 14A and the bag body 14B may be arranged with a predetermined interval between them.

[0031] The bag body 14A and the bag body 14B are connected to the intake and exhaust units 16A and 16B, respectively. The intake and exhaust units 16A and 16B control the intake and exhaust of the bag body 14A and the bag body 14B, thereby controlling the shape of each. By providing a plurality of bag bodies 14A and 14B in this way, the gripping surface formed by the bag bodies 14A and 14B can be shaped to more closely resemble the shape of the workpiece W to be gripped. This makes it possible to grip the workpiece W more stably.

[0032] It is also possible to operate only one of the intake and exhaust unit 16A and the intake and exhaust unit 16B. In other words, it is also possible to hold the workpiece W by the magnet 12 with one of the bag body 14A and the bag body 14B in a hardened state and the other in a softened state.

[0033] The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit of the present invention. In the above example, the magnetic attraction unit applies magnetic force to the workpiece W after deforming the bag body 14 into a shape conforming to the workpiece W, but the present invention is not limited to this. For example, the gas in the bag body 14 may be exhausted by the intake and exhaust unit 16 after the workpiece W is gripped by the magnet 12. [Explanation of symbols]

[0034] 10 Gripping device 11. Housing 12. Magnets 13 Air Cylinder 14 Bag body 14A, 14B Bag body 15 Powder 16 Intake and exhaust section Double work

Claims

1. A flexible and airtight bag for containing powder and granular material, which is in contact with the workpiece, which is a magnetic material; An intake and exhaust unit that exhausts gas from the bag body or supplies gas to the bag body, thereby deforming the bag body to conform to the shape of the workpiece when the bag body comes into contact with the workpiece; a magnetic attraction portion that applies a magnetic force to the workpiece and grips the workpiece while the bag body is deformed to follow the shape of the workpiece; A gripping device comprising:

2. The powder is a magnetic powder, The magnetic attraction portion applies a magnetic force to the workpiece via the powder or granular material. The gripping device according to claim 1 .

3. The magnetic attraction unit applies a magnetic force to the workpiece after deforming the bag body to conform to the shape of the workpiece. The gripping device according to claim 1 .

4. The magnetic attraction unit is capable of switching between a gripping state in which the workpiece is gripped by magnetic force and a release state in which the gripping is released. The gripping device according to claim 1 .

5. The magnetic attraction portion is A magnet provided within the housing; a switching unit that is disposed within the housing and that brings the magnet close to the workpiece to bring the gripping state into effect and moves the magnet away from the workpiece to bring the gripping state into effect; Including, The gripping device according to claim 4.

6. A step of discharging gas from or supplying gas to a flexible and airtight bag containing powder or granular material, the bag being in contact with a workpiece that is a magnetic material, thereby deforming the bag to conform to the shape of the workpiece when the bag comes into contact with the workpiece; a step of applying a magnetic force to the workpiece to grip the workpiece while the bag body is deformed to conform to the shape of the workpiece; A gripping method comprising:

Images