Holding device and holding method

Abstract

The invention relates to a gripping device and a gripping method. A gripping device according to an embodiment includes: a bag body in contact with a workpiece as a magnet, the bag body having flexibility and gas tightness and accommodating a granular material; an intake and exhaust unit that, when the bag body is in contact with the workpiece, deforms the bag body by discharging gas from the bag body or supplying gas to the bag body so as to conform to the shape of the workpiece; and a magnetic attraction unit that grips the workpiece by applying a magnetic force to the workpiece in a state in which the bag body is deformed to conform to the shape of the workpiece.

Description

Technical Field

[0001] The invention relates to a holding device and a holding method. Background Art

[0002] As an end effector of an industrial robot, there is a gripper, a gripping device for gripping an object. Japanese Unexamined Patent Application Publication No. 2019-155534 (JP 2019-155534 A) discloses a magnetic gripper that holds a workpiece as a magnet by magnetic force. The magnetic gripper disclosed in JP 2019-155534 A is a permanent magnet type magnetic gripper, and can be switched between a holding state in which the workpiece is held by magnetic force and a release state in which the hold is released.

[0003] In JP 2019-155534 A, the permanent magnet is arranged in a shell made of a non-magnetic material with an opening at the bottom so that it can move in the vertical direction with the magnetized surface facing downward. The opening portion of the shell is formed into an inclined shape. When the entire magnetized surface of the permanent magnet protrudes from the opening portion of the shell, the magnetic holder enters a holding state, and when at least a portion of the magnetized surface is immersed in the interior of the shell, the magnetic holder enters a release state.

[0004] In addition, Japanese Unexamined Patent Application Publication No. 2013-220492 (JP 2013-220492 A) discloses a holding device for holding an object by pressing a bag against an object placed on a support surface. In JP 2013-220492 A, a deformable bag is pressed against an object, and a granular material is introduced into the inside of the bag to expand the bag and reduce the space between the bag and the object, and then, among the granular material and gas inside the bag, only the gas is sucked out and discharged to the outside of the bag. This increases the friction between the particles of the granular material inside the bag, and helps the bag to maintain its shape. Summary of the invention

[0005] In JP 2019-155534 A, the magnetized surface of the permanent magnet facing downward becomes the gripping surface for gripping the workpiece. When 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, when rotation occurs between the gripping surface and the workpiece, it becomes more difficult to grip the workpiece with the gripper.

[0006] When replacing a gripper according to the shape and posture of an object to be held, it is necessary to select a suitable gripper and use it as a replacement. In addition, complex calculations are required to plan the gripping of the object to be held by the selected gripper and estimate the posture of the workpiece from the beginning of gripping to the completion of gripping. It is also assumed that an industrial robot equipped with such a gripper operates by performing, for example, machine learning. This work associated with replacing the gripper may result in a reduction in the efficiency of the robot's gripping work. In addition, in JP 2013-220492A, it is necessary to reduce the space between the bag body and the object to a degree that the object can be held, so there is a problem of the object being restricted.

[0007] The present invention provides a holding device and a holding method, which can stably hold workpieces as magnets in various shapes.

[0008] A first aspect of the present invention relates to a holding device, comprising a bag body, an air intake and exhaust unit, and a magnetic attraction unit. The bag body contacts a workpiece as a magnet, the bag body has flexibility and airtightness and contains granular materials. When the bag body contacts the workpiece, the air intake and exhaust unit deforms the bag body to conform to the shape of the workpiece by exhausting gas from the bag body or supplying gas to the bag body. The magnetic attraction unit holds the workpiece by applying a magnetic force to the workpiece in a state where the bag body is deformed to conform to the shape of the workpiece.

[0009] In the first aspect, the granular material may be magnetic powder, and the magnetic attraction unit may apply a magnetic force to the workpiece via the granular material.

[0010] In the first aspect, the magnetic attraction unit may apply the magnetic force to the workpiece after deforming the bag body to conform to the shape of the workpiece.

[0011] In the first aspect, the magnetic attraction unit may be configured to switch between a gripping state in which the workpiece is gripped by magnetic force and a release state in which the grip is released.

[0012] In the first aspect, the magnetic attraction unit may include a magnet installed inside a shell, and a switching unit in the shell, which moves the magnet close to the workpiece to bring the magnetic attraction unit into the holding state, and moves the magnet away from the workpiece to bring the magnetic attraction unit into the release state.

[0013] A second aspect of the present invention relates to a holding method, comprising: when a bag body is in contact with a workpiece, the bag body is deformed to conform to the shape of the workpiece by discharging gas from the bag body or supplying gas to the bag body, the bag body is flexible and airtight and contains granular material, the bag body is in contact with the workpiece serving as a magnet, and the workpiece is held by applying a magnetic force to the workpiece in a state where the bag body is deformed to conform to the shape of the workpiece.

[0014] By utilizing various aspects of the present invention, workpieces as magnets of various shapes can be stably held. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals represent like elements, and wherein:

[0016] Figure 1 is a schematic diagram showing the configuration of a holding device according to a first embodiment;

[0017] Figure 2 is a diagram showing a holding method according to the first embodiment; and

[0018] Figure 3 is a schematic diagram showing the configuration of a grip device according to a second embodiment. DETAILED DESCRIPTION

[0019] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Numerical values, shapes, materials, components, arrangement positions of components, steps, and the order of steps, etc. shown in the following embodiments are examples and do not limit the present disclosure.

[0020] In addition, since the drawings are simplified, the technical scope of the present disclosure should not be narrowly interpreted based on the description in the drawings. It should be noted that for the purpose of illustration, the drawings are not drawn to scale. In each of the drawings, the same elements are represented by the same reference numerals, and redundant descriptions will be omitted.

[0021] First embodiment

[0022] Figure 1 1 is a schematic diagram showing the configuration of the holding device 10 according to the first embodiment. Figure 1 As shown, the holding device 10 includes a housing 11, a magnet 12, a cylinder 13, a bag 14, a granular material 15, and an air intake and exhaust unit 16. The holding device 10 is a magnetic holding device that can switch between a holding state in which a workpiece W as a magnet is held by magnetic force and a release state in which the holding is released.

[0023] exist Figure 1In the example shown, the housing 11 is a hollow rectangular parallelepiped. An opening portion is provided at the lower end of the housing 11. The housing 11 is made of a non-magnetic body. Examples of the material of the housing 11 include stainless steel, copper, and aluminum. In addition, the housing 11 may be made of resin or ceramics.

[0024] The magnet 12 is arranged in the housing 11. The magnet 12 may include, for example, a permanent magnet such as a ferrite magnet or a neodymium magnet. The magnet 12 may be an electromagnet, the generation of which magnetic force may be electrically controlled.

[0025] The magnet 12 can move vertically in the housing 11. Figure 1 In the example shown, the cylinder 13 is provided at the upper part of the housing 11, and the cylinder 13 moves the magnet 12 vertically in the housing 11. The magnet 12 and the cylinder 13 correspond to the magnetic attraction unit described in the claims. Inside the housing 11, the cylinder 13 serves as a switching unit that moves the magnet 12 close to the workpiece W to bring it into a gripping state, and moves the magnet 12 away from the workpiece W to bring it into a releasing state. The mechanism for moving the magnet 12 may be another mechanism, such as an electric actuator equipped with a motor.

[0026] For example, by making the magnet 12 protrude from the opening portion of the housing 11, the cylinder 13 can be brought into a gripping state, and by sinking the magnet 12 into the housing 11, the cylinder 13 can be brought into a released state. As in JP 2019-155534A, the lower end of the housing 11 may be an inclined opening portion. As a result, a state in which the magnet 12 partially protrudes from the housing 11 and partially sinks into the housing 11 is provided between the state in which the magnet 12 protrudes from the housing 11 and the state in which the magnet 12 sinks into the housing 11. According to this configuration, the grip of the workpiece W by the magnet 12 is released in stages.

[0027] At the lower end of the shell 11, a bag body 14 for accommodating a granular material 15 is provided. The bag body 14 is a part of the holding device 10 for holding the workpiece W. The bag body 14 is flexible and airtight, and has a space inside. The bag body 14 is made of an elastically deformable material such as rubber or silicone rubber. The bag body 14 is not limited to being elastically deformable, as long as its shape can be reversibly deformed by an external force. In addition, a material with high gas barrier properties can be used to prevent gas from escaping from the bag body 14.

[0028] The granular material 15 is accommodated in the space of the bag 14. The granular material 15 filled in the bag 14 behaves like a solid or a fluid due to a jamming transition, in which the bag 14 is transformed into a hardened state that makes the bag 14 resistant to deformation, or the bag 14 is transformed into a softened state that makes deformation possible.

[0029] The air intake and exhaust unit 16 is connected to the bag body 14. For example, a vacuum pump or the like may be used as the air intake and exhaust unit 16. The air intake and exhaust unit 16 reduces the pressure inside the bag body 14 by exhausting the gas inside the bag body 14, and pressurizes the inside of the bag body 14 by supplying gas to the bag body 14. The bag body 14 and the air intake and exhaust unit 16 may be connected by a cylindrical tube made of metal or resin.

[0030] The air intake and exhaust unit 16 reduces the pressure inside the bag body 14 to a predetermined negative pressure by exhausting gas (air) from the bag body 14, and brings the granular material 15 inside the bag body 14 into a state of close contact with each other. In this way, the gaps between the particles of the granular material 15 are reduced, making it impossible for the granular material 15 to move. As a result, the granular material 15 solidifies, and the bag body 14 is transformed into a hardened state that makes the bag body 14 resistant to deformation.

[0031] The air intake and exhaust unit 16 also supplies gas to the bag body 14 to restore the pressure inside the bag body 14 to, for example, atmospheric pressure, thereby creating gaps between the particles of the granular material 15 inside the bag body 14. By forming gaps between the particles of the granular material 15 in this way, the granular material 15 can easily move in the bag body 14. As a result, the granular material 15 becomes fluid, and the bag body 14 becomes soft and easily deformed. That is, by controlling the air intake and exhaust of the bag body 14 by the air intake and exhaust unit 16, the bag body 14 can be switched to a hardened state or a softened state.

[0032] As the granular material 15, a granular material 15 that easily flows when the shape of the bag body 14 is changed to conform to the shape of the workpiece W is used. The shape of the granular material 15 is not particularly limited, and may be a spherical, polygonal, jagged, and uneven shape, etc. The size of the granular material 15 may be such that it is not discharged together with the gas when the gas is discharged from the bag body 14. The size of the granular material 15 may be, for example, about 3 mm to 10 mm in diameter.

[0033] A filter may be provided between the bag body 14 and the air intake and exhaust unit 16. The filter prevents the granular material 15 from entering the air intake and exhaust unit 16. Such a filter has a mesh structure smaller than the diameter of the granular material 15, for example.

[0034] The granular material 15 may be a non-magnetic powder. In this case, as the granular material 15, zirconia balls, resin beads, glass beads, etc. may be used. Furthermore, as the granular material 15, coffee bean powder may be used. Furthermore, the granular material 15 may be a magnetic powder. In this case, iron balls or the like are used as the granular material 15. When magnetic powder is used as the granular material 15, the granular 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 via the granular material 15. The material of the granular material 15 is not limited to this example, and may be any material that can be filled into the bag body 14 and exhibits a congestion transition.

[0035] Figure 2 is a diagram showing a holding method according to a first embodiment. As an example, first, the bag body 14 in a softened state is pressed against the workpiece W. Then, the air intake and exhaust unit 16 discharges the gas inside the bag body 14, thereby changing the shape of the bag body 14 to match the shape of the workpiece W. Then, with the bag body 14 deformed to conform to the shape of the workpiece W, the magnet 12 moves close to the workpiece W, and a magnetic force is applied to the workpiece W to hold the workpiece W.

[0036] Figure 2 FIG. 1 shows a state where the workpiece W, which is a magnetic body, is held by the magnetic force of the magnet 12. Figure 2 As shown, the bag body 14 in a hardened state has a shape conforming to the workpiece W. When the workpiece W is gripped by the magnet 12 in such a manner that the shape of the workpiece W matches the shape of the bag body 14, the workpiece W can be stably held without rotating on the gripping surface.

[0037] Furthermore, when the shape or posture of the workpiece W is different, the air intake and exhaust unit 16 controls the air intake and exhaust of the bag body 14 so that the bag body 14 can be deformed into a different shape. This makes it possible to suppress a decrease in work efficiency due to the holder replacement work.

[0038] Second embodiment

[0039] Figure 3 1 is a schematic diagram showing the construction of a holding device 10A according to a second embodiment. The second embodiment differs from the first embodiment in that two bags 14A, 14B are provided, each containing a granular material 15. Figure 3 In the example shown, the bag body 14A and the bag body 14B are arranged side by side on the opening portion side of one housing 11. The number of the bag bodies 14 is not limited to this example. In addition, the bag body 14A and the bag body 14B may be arranged with a predetermined interval therebetween.

[0040] The air intake and exhaust unit 16A is connected to the bag body 14A, and the air intake and exhaust unit 16B is connected to the bag body 14B. The air intake and exhaust unit 16A controls the air intake and exhaust of the bag body 14A and controls the shape of the bag body 14A, and the air intake and exhaust unit 16B controls the air intake and exhaust of the bag body 14B and controls the shape of the bag body 14B. By arranging a plurality of bag bodies 14A, 14B in this way, the gripping surface formed by the bag bodies 14A, 14B can be shaped to conform to the shape of the workpiece W to be gripped. This enables the workpiece W to be gripped more stably.

[0041] Only one of the air intake and exhaust unit 16A or the air intake and exhaust unit 16B may be operated. That is, the workpiece W can be held by the magnet 12 even when one of the bag bodies 14A and 14B is in a hardened state and the other is in a softened state.

[0042] The present invention is not limited to the embodiments and can be appropriately modified without departing from the spirit. In the example, the magnetic attraction unit deforms the bag body 14 to conform to the shape of the workpiece W and then applies magnetic force to the workpiece W, but the present invention is not limited thereto. For example, after the workpiece W is gripped by the magnet 12, the gas inside the bag body 14 can be discharged by the air intake and exhaust unit 16.

Claims

1. A holding device, characterized in that include: a bag body in contact with the workpiece as a magnet, the bag body being flexible and airtight and containing a granular material; an air intake and exhaust unit, which, when the bag body contacts the workpiece, deforms the bag body to conform to the shape of the workpiece by exhausting gas from the bag body or supplying gas to the bag body; as well as A magnetic attraction unit holds the workpiece by applying a magnetic force to the workpiece in a state where the bag body is deformed to conform to the shape of the workpiece.

2. The holding device according to claim 1, characterized in that: The granular material is magnetic powder; and The magnetic attraction unit applies a magnetic force to the workpiece via the granular material.

3. The holding device according to claim 1, characterized in that: The magnetic attraction unit applies a magnetic force to the workpiece after deforming the bag body to conform to the shape of the workpiece.

4. The holding device according to claim 1, characterized in that: The magnetic attraction unit is configured to switch between a gripping state in which the workpiece is gripped by magnetic force and a release state in which the grip is released.

5. The holding device according to claim 4, characterized in that The magnetic attraction unit comprises: a magnet mounted inside the housing, and A switching unit in the housing moves the magnet closer to the workpiece to bring the magnetic attraction unit into the gripping state, and moves the magnet away from the workpiece to bring the magnetic attraction unit into the releasing state.

6. A holding method, characterized in that include: When the bag body contacts the workpiece, the bag body is deformed to conform to the shape of the workpiece by exhausting gas from the bag body or supplying gas to the bag body, the bag body having flexibility and airtightness and containing granular material, the bag body being in contact with the workpiece as a magnet; and The workpiece is held by applying a magnetic force to the workpiece in a state where the bag body is deformed to conform to the shape of the workpiece.

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