JP2017080825A - Gripping apparatus and gripping method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gripping apparatus capable of surely and safely gripping a workpiece having a limited adhesive surface and a workpiece easily broken by an external force, and a gripping method using the same.SOLUTION: This gripping apparatus is provided with: a fixing member 12 having a pressure-receiving surface 12a; a core member 14 fixed to the center of the pressure-receiving surface 12a; a hollow gripping bag 16 attached to the pressure-receiving surface 12a in a manner of surrounding the core member 14; grains 18 housed in the gripping bag 16; and a decompression device 20. The decompression device 20 can decompress and shrink the inside of the gripping bag 16, and return the inside to atmospheric pressure. The core member 14 projects into the gripping bag 16. The gripping bag 16 is airtight and deformable. The grains 18 occupy a total volume surrounding at least a part of a workpiece W.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gripping device using particles and a gripping method using the gripping device.

  The transport robot is an industrial robot that transports a workpiece at an extraction position to another position, and usually has a robot hand using a claw that grips the workpiece (grip target). However, when the shape of the workpiece is irregular, it may not be possible with existing claws.

  Therefore, a gripper (hereinafter referred to as “gripper”) using a granule has been proposed as a robot hand that grips and moves a workpiece regardless of the shape of the workpiece (for example, Patent Documents 1 and 2).

  In “Gripping and Releasing Device and Method” of Patent Document 1, the gripper includes a large amount of granular material wrapped with an elastic film, and a wide range of objects (workpieces) can be rapidly formed by a combination of positive pressure and negative pressure. Can be grabbed and released. This gripper passively conforms to the shape of the workpiece, and then sucks in a vacuum to grip it tightly, then uses positive pressure to release the workpiece and return to a deformable state.

  The “gripper” of Patent Document 2 includes a fixing member having a pressure receiving surface, a hollow bag attached in close contact with the pressure receiving surface and filled with granules, and a pressure in the hollow bag is reduced and returned to atmospheric pressure. A decompression device capable of Furthermore, it has a filter for preventing particles from entering the decompression device. The filter can permeate air when the hollow bag is decompressed or pressurized by the decompression device, and protrudes into the hollow bag.

Special table 2013-523478 gazette JP 2012-218108 A

  In the conventional gripper described above, a hollow bag filled with granules is pressed against a workpiece (for example, an object to be pinked), and the hollow bag is decompressed to solidify the granules, thereby fitting the workpiece into the hollow bag. The work was made movable.

However, in the conventional gripper, there is a possibility that the granule that does not surround the workpiece is solidified by receiving an external force, and the portion surrounding the workpiece is not sufficiently solidified. For example, a work with few surfaces that can be contacted (for example, “a stuffed toy with many irregularities and a surface covered with hair”), when the hollow bag is shrunk, the work itself is shrunk under low pressure. There was a possibility that the granules could not be gripped without solidifying sufficiently.
In addition, when the hollow bag is pressed against the workpiece to be fitted, if the internal granules are compressed and a frictional force is generated between the granules, the movement resistance of the granules acts on the workpiece and is easily broken by non-uniform external force. There was a possibility of damaging the workpiece (eg egg or tofu).

  That is, conventional gripper workpieces (objects to be grasped) are limited to those having a close-contactable surface and not broken even when the hollow bag is pressed. For this reason, it is difficult to grip a workpiece with few surfaces that can be in close contact with each other or a workpiece that is fragile due to uneven external force.

  The present invention has been developed to solve the above-described problems. That is, an object of the present invention is to provide a gripping device that can securely and safely grip a work with few surfaces that can be in close contact with each other, or a work that is easily broken by non-uniform external force, and a gripping method using the gripping apparatus. is there.

According to the present invention, a fixing member having a pressure receiving surface;
A core member fixed to the center of the pressure receiving surface;
A hollow gripping bag that is attached to the pressure-receiving surface so as to surround the core member, has airtightness, and is deformable.
Granules accommodated in the gripping bag so as to be flowable leaving a space inside;
A decompression device capable of decompressing and contracting the inside of the gripping bag and returning the pressure to atmospheric pressure,
The core member protrudes into the gripping bag;
A gripping device is provided in which the granules occupy a total volume surrounding at least a portion of the workpiece.

Comprising a breathable hollow granule bag housed inside the gripping bag,
The hollow particle bag is an annular bag that accommodates the particles therein, and has an opening that can accommodate at least a part of the workpiece at the center of the bag. Thereby, the workpiece | work located in opening can be hold | gripped with a cyclic | annular bag body.

  The core member has a spherical shape, a hemispherical shape, a cone shape, a prefix cone shape, or a rod shape. These shapes can be optimally gripped by selecting them according to the shape of the workpiece.

  The gripping bag has a recess recessed inwardly on the outer surface thereof. By this depression, the workpiece can be arranged in a portion where the core member exists, the particles can be moved so as to be surely gripped, and the workpiece can be gripped.

According to the present invention, there is also a gripping method using the gripping device described above,
(A) In a state where the pressure receiving surface is faced down and the inside of the gripping bag communicates with the outside, the gripping device is moved until the lower end of the core member is close to the workpiece, thereby Move the particles inside so as to surround at least a part of the workpiece,
(B) Next, the inside of the gripping bag is depressurized and contracted, thereby reducing the gaps between the particles and bringing them into close contact with each other, and the workpiece is formed by the lump of particles formed by the frictional force between the particles. There is provided a gripping method for gripping from the side.

As a result, there is a space inside the gripping bag during the movement of the granules in (A), and the granules can flow. Therefore, when the bottom surface of the gripping bag is recessed so as to surround the work, The body can flow freely without being compressed. Further, since the core member does not come into contact with the workpiece, only a part of the weight of the whole granule acts on the workpiece.
In addition, since the lower end of the core member is close to the workpiece and the ratio of the particles that do not surround the workpiece is small during the decompression of (B), the portion surrounding the workpiece can be sufficiently solidified.

  According to the present invention, the core member protrudes into the gripping bag. Moreover, the granule is accommodated in the gripping bag so as to be flowable leaving a space. Further, the granule occupies a total volume surrounding at least a part of the workpiece.

  Therefore, with the pressure receiving surface facing downward and the inside of the gripping bag communicating with the outside, the gripping device is moved (lowered) until the lower end of the core member comes close to the workpiece, so that the granules inside the gripping bag. Can be moved so as to surround at least a part of the workpiece.

  Next, the inside of the gripping bag is depressurized and contracted to reduce the gaps between the particles and closely adhere to each other, and the workpiece is formed by the lump of particles (granule lump) formed by the frictional force between the particles. It can be gripped from the side.

  At this time, the lump of particles (granule lump) contracts as a whole from the state of surrounding at least a part of the work, so that the contact area with the work is large and the contact pressure of the contact surface is low. Furthermore, this surface pressure is proportional to the difference between the internal pressure of the gripping bag and the atmospheric pressure during decompression, and therefore can be variably controlled by adjusting the internal pressure during decompression.

  Therefore, the gripping device of the present invention can securely and safely grip a workpiece with few surfaces that can be brought into close contact with, and a workpiece that is easily broken by a non-uniform external force.

It is a whole block diagram of the conveyance robot provided with the holding | gripping apparatus of this invention. It is a section conceptual diagram of a 1st embodiment of a grasping device of the present invention. It is a conceptual diagram which shows another embodiment of a core member. It is a section conceptual diagram showing another embodiment of a grasping bag. It is a section conceptual diagram of the grasping method using the grasping device of a 1st embodiment. It is another cross-sectional conceptual diagram of the holding | grip method using the holding | grip apparatus of 1st Embodiment. It is a section conceptual diagram of a grasping device of a 2nd embodiment and a grasping method using the same. It is a section conceptual diagram of a grasping device of a 3rd embodiment, and a grasping method using the same.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is an overall configuration diagram of a transfer robot 1 including a gripping device 10 according to the present invention.
In this figure, 1 is a transfer robot, 2a, 2b and 2c are robot arms, 3 is a robot hand, 4 is a robot support, 5a, 5b and 5c are joints, and 6 is a connection.
In this figure, W is a work to be gripped (a gripping object), and 7 is a work container.

In the present invention, the workpiece W has an indefinite shape. In this example, the workpiece W, which is a gripping object, is stored in the workpiece container 7, but the workpiece W may be directly placed on a table or the like.
Further, in the present invention, the workpiece W has few surfaces that can be closely contacted or is slippery “a stuffed animal with many irregularities and the surface is covered with hair”, or an egg (raw egg, boiled) that is fragile due to uneven external force. Egg), but other objects may be used. The non-uniform force referred to here is a force when a stress difference between the contact surface and the non-contact surface is large when the contact area with the workpiece is small, and excessive stress is applied at the contact boundary portion.

  In this example, the transfer robot 1 is a vertical articulated robot fixed to the upper surface of the robot support 4, but the present invention is not limited to this, and may be another robot (a SCARA robot or an orthogonal robot). .

The joints 5a to 5c connect the robot arms 2a to 2c and the hand part 3 of the transfer robot 1, respectively. The rotation axes C1 to C3 (axis perpendicular to the paper surface of FIG. 2) and C4 (longitudinal direction of the robot arm 2a). Can be rotated around an axis extending to
The connection unit 6 connects the gripping device 10 and the hand part 3 of the robot.

  The gripping device 10 is mounted on the hand portion 3 of the transfer robot 1 and is moved three-dimensionally within a predetermined operating range by the transfer robot 1 having the robot arms 2a to 2c and the joints 5a to 5c, and has a free posture. Can be taken.

FIG. 2 is a schematic cross-sectional view of the first embodiment of the gripping device 10 of the present invention.
In this figure, the gripping device 10 of the present invention includes a fixing member 12, a core member 14, a gripping bag 16, a granule 18, and a decompression device 20.

  The fixing member 12 has a pressure receiving surface 12 a that is fixedly connected to the connection portion 6 of the transport robot 1.

  The core member 14 is fixed to a substantially central portion of the pressure receiving surface 12a. Further, the core member 14 has a central portion protruding so as to keep the particles 18 away from the core member 14 by contact with the gripping back surface or the particles themselves. In FIG. 2, the shape of the core member 14 is spherical or substantially spherical.

FIGS. 3A and 3B are conceptual diagrams showing another embodiment of the core member 14, in which FIG. 3A shows a hemispherical shape and FIG. 3B shows a core member 14 having a prefix cone shape.
As shown in this figure, the shape of the core member 14 may be a hemispherical shape, a cone shape, a prefix cone shape (a prefix polygon cone, a prefix cone), or a rod-like shape with a central portion protruding downward.

In this example, the core member 14 is a rigid body whose outer dimension does not change due to a change in the internal pressure of the gripping bag 16.
That is, the core member 14 is solid or does not communicate with the inside of the gripping bag 16 even if it is not solid, and the material does not change in shape under reduced pressure and atmospheric pressure (for example, metal or (Plastic).
With this configuration, by bringing the core member 14 close to the workpiece W, the particles 18 can be moved in the direction away from the core member 14 inside the gripping bag 16 so as to wrap the workpiece W.

The core member 14 may be a hollow elastic bag that can be inflated by internal pressure.
With this configuration, the core member 14 can be expanded by pressurizing the pressure in the core member 14 to a positive pressure, and the size can be made suitable for the workpiece W. Further, the expansion of the particles 18 in the gripping bag 16 can be promoted by this expansion.

  In FIG. 2, a gripping bag 16 is an airtight and deformable hollow bag, and is attached to the pressure receiving surface 12a so as to surround the core member 14.

  In FIG. 2, the shape of the gripping bag 16 is spherical in this example. However, the shape of the gripping bag 16 may be other shapes, for example, a hemispherical shape, a prefix cone shape (a prefix polygon cone, a prefix cone).

FIG. 4 is a conceptual diagram showing another embodiment of the gripping bag 16.
As shown in this figure, the outer surface (for example, the lower surface) of the gripping bag 16 may have a recess 16a that is recessed inward (upper side in the figure). The recess 16a is preferably a hemispherical recess. However, the recess 16a may be, for example, an oval or rectangular recess.
The recess 16a preferably has a size that can surround at least a part of the workpiece W.

  By providing the recess 16a described above, when the outer surface (for example, the lower end) of the core member 14 is brought close to the workpiece W, at least a part of the workpiece W is accommodated in the recess 16a without deforming the gripping bag 16. Thus, at least a part of the workpiece W can be surrounded by the particles 18.

The gripping bag 16 needs to be made of a material having flexibility and flexibility that change the shape of the workpiece W along the surface shape of the workpiece W and an airtightness that does not allow gas to flow. Moreover, the material needs to be able to grip the workpiece W from the side surface by friction.
For example, the material of the gripping bag 16 is preferably natural rubber, latex rubber, elastic plastic, nylon or the like. The thickness of the gripping bag 16 is preferably 0.1 to 1.0 mm, for example. Further, a fine texture, pattern or groove may be formed on the surface like a fingerprint of a human finger.

The granules 18 are accommodated in the gripping bag 16 so as to be flowable leaving a space.
The granule 18 occupies a total volume surrounding at least a part of the workpiece W when the inner pressure of the gripping bag 16 is atmospheric pressure and the outer surface (for example, the lower end) of the core member 14 is close to the workpiece W.
This total volume is the state shown in FIG. 2, that is, the pressure receiving surface 12 a facing downward, and the space between the gripping bag 16 and the core member 14 when the internal pressure of the gripping bag 16 is atmospheric pressure is three to four quarters. It is preferable that a space where the particles 18 do not exist is left in the upper part.
Further, the volume of the space where the particles 18 do not exist is preferably at least half of the total volume of the workpiece W, more preferably at least the total volume of the workpiece W.

In the state shown in FIG. 2 under gravity with the pressure receiving surface 12a facing downward, the distance in the height direction between the lower end of the core member 14 and the lower end of the gripping bag 16 is preferably more than half of the total height of the workpiece W, more preferably Is preferably greater than the total height of the workpiece W.
In this state, the upper surface of the granular material 18 is preferably located at substantially the same height as the lower end of the core member 14 or above it.

With this configuration, the gripping device 10 is moved by the transfer robot 1 until the lower end of the core member 14 comes close to the workpiece W with the pressure receiving surface 12a facing downward and the inside of the gripping bag 16 communicating with the outside ( By lowering), the gas (for example, air) in the upper space where the particles 18 are not present can be exhausted to the outside.
A filter (not shown) is provided between the inside and the outside of the gripping bag 16 so that the particles 18 do not flow out of the gripping bag 16.

  The granules 18 preferably have a repulsive force that returns to its original shape when contracted. Such granules 18 are, for example, a foamed resin (for example, styrofoam) having closed cells or open cells inside. However, it is better not to have a repulsive force compared to the rigidity of the core member 14.

With this structure, when the inside of the gripping bag 16 is depressurized and contracted, and the particles 18 are brought into close contact with the shape holding the workpiece W by reducing the gaps between the particles, the repulsive force of the particles themselves The gripping force of the workpiece W can be increased.
For example, when spherical foam beads and glass beads are used as the granules 18, a repulsive force is applied to the foam beads after decompression to return to the original shape, so that the gripping force is higher than in the case of glass beads. Has been confirmed.
In addition, this invention is not limited to this structure, The material (for example, glass bead) which a shape hardly changes under pressure reduction and atmospheric pressure may be sufficient.

  In the present invention, “reduced pressure” means that the gripping bag 16 is contracted, thereby reducing the space between the particles and bringing them into close contact with each other, and the work W is formed by the lump of particles 18 formed by the frictional force between the particles. Is a negative pressure or a degree of vacuum that can be gripped from the side.

  Moreover, it is preferable that the granular material 18 has the fluidity | liquidity which moves below by the dead weight under atmospheric pressure. That is, the granules 18 are dried, and the angle of repose in the dry state is preferably 45 degrees or less, more preferably 30 degrees or less under atmospheric pressure.

With this configuration, the gripping device 10 is moved (lowered) until the lower end of the core member 14 comes close to the workpiece W in a state where the pressure receiving surface 12a faces downward and the inside of the gripping bag 16 communicates with the outside. A part of the gripping bag 16 positioned around the workpiece W becomes lower than the upper portion of the workpiece W.
Therefore, the core member 14 can move the particles 18 inside the gripping device 10 so as to surround at least a part of the workpiece W by using the fluidity of the particles 18.

The lower end position of the core member 14 when the pressure receiving surface 12a faces downward and approaches the workpiece W may be a position spaced from the upper end of the workpiece W by a predetermined interval. This “predetermined interval” is set so that the downward force transmitted to the workpiece W via the granule 18 positioned between the core member 14 and the gripping bag 16 is equal to or less than a threshold value.
This threshold value should be a size that does not break the workpiece W (eg, an egg that is fragile due to non-uniform external force). For example, the predetermined interval is 5 to 50 mm, and the downward force threshold is 1 to 2N.

Moreover, it is preferable that the granules 18 have a friction coefficient that holds the workpiece W in close contact with each other by contraction of the gripping bag 16.
With this configuration, the inside of the gripping bag 16 is depressurized and contracted, and the granule 18 having the shape maintained is obtained by closely attaching the granule 18 to the shape that holds the workpiece W by reducing the gap between the granules. The workpiece W can be gripped from the side surface by the lump (hereinafter referred to as “granule lump”).

  Furthermore, it is preferable that the granular material 18 has a specific gravity that does not deform the workpiece W by its own weight under atmospheric pressure.

With this configuration, when the pressure receiving surface 12a faces downward and the gripping device 10 is moved, the core member 14 moves the granules 18 inside the gripping bag 16 so as to surround at least a part of the workpiece W. The deformation of the workpiece W due to the specific gravity of the particles 18 can be prevented or reduced.
Since the core member 14 does not come into contact with the workpiece W during the movement of the particles, only a part of the weight of the entire particles acts on the workpiece W.

  That is, by reducing the total weight of the particles 18, the particles 18 can be moved around the workpiece W only by placing the gripping device 10 on the workpiece W, and the pressing load acting on the workpiece W Can be greatly reduced to prevent or reduce the deformation thereof.

The above-mentioned granules 18 are, for example, foamed resin (for example, polystyrene foam), glass beads, plastic, polymer particles, hollow resin beads, granules having cavities inside, glass spheres, metal particles, metal spheres, crushed rubber, sand, Etc.
Further, the granule 18 is obtained by crushing roasted beans (eg, coffee beans) or dried wood chips as raw materials, taking out coffee beans, corn starch, corn meal, dried ground corn peel, rice, sawdust, ground It may be a crushed nut shell, oats, salt, seeds, buckwheat husk, etc.

  The particles 18 are preferably spherical in order to facilitate flow when the gripping device 10 is made to follow the shape of the workpiece W. However, the present invention is not limited to this, and may have a shape other than a spherical shape (for example, a rectangular parallelepiped, a polyhedron, etc.).

The size of the granules 18 is reduced by shrinking the inside of the gripping bag 16, thereby reducing the gaps between the granules and bringing them into close contact with each other, and the mass of the granules 18 formed by the frictional force between the granules. It is preferable that the workpiece W can be gripped from the side surface by the (granular mass).
That is, the maximum diameter of the particles 18 is, for example, 1/10 or less of the minimum value of the width, thickness, and length of the workpiece W, and preferably 1/1000 or more.

For example, the long diameter of the particles 18 is preferably 0.1 mm or more, and more preferably 1 to 5 mm.
When the granule 18 is a spherical foam bead, it has been experimentally confirmed that the gripping force is larger in the order of the diameter of the foam bead of 5 mm, 3 mm, and 1 mm.
Moreover, the air ratio in a holding | grip bag can be enlarged by making the granule 18 relatively large.

The decompression device 20 contracts the gripping bag 16 by decompressing the inside of the gripping bag 16 to grip the workpiece W, and releases the gripping of the workpiece W by returning the pressure in the gripping bag 16 to atmospheric pressure. .
In this example, the decompression device 20 is installed in the connecting portion 6, but may be in another place as long as these functions are not impaired.

  1 and 2, the gripping device 10 of the present invention further includes a control device 26. The control device 26 controls the three-dimensional movement of the transfer robot 1 and the gripping device 10.

Further, the control device 26 executes the following control.
(A) With the pressure-receiving surface 12a facing downward and the inside of the gripping bag 16 communicating with the outside, the gripping device 10 is moved until the lower end of the core member 14 is close to the workpiece W. The granule 18 is moved inside so as to surround at least a part of the workpiece W.
(B) Next, the inside of the gripping bag 16 is depressurized and contracted, thereby reducing gaps between the particles and bringing them into close contact with each other, and a lump of particles 18 (particles) formed by the frictional force between the particles. The workpiece W is gripped from the side surface by the lump).
(C) With the workpiece W gripped, the internal pressure of the gripping bag 16 is returned to the atmospheric pressure, and the workpiece W is released.

With the above-described configuration, the gripping device 10 is moved (lowered) until the lower end of the core member 14 comes close to the workpiece W with the pressure receiving surface 12a facing downward and the inside of the gripping bag 16 communicating with the outside. Thus, the particles 18 can be moved inside so as to surround at least a part of the workpiece W.
“At least a part of the workpiece W” means at least two points in the width direction or the length direction in the plan view of the workpiece W when the workpiece W is gripped by the gripping device 10, and grips and conveys the workpiece W. It means the part that can.

  FIG. 5 is a conceptual cross-sectional view of a gripping method using the gripping device 10 of the first embodiment. In this example, it is assumed that the workpiece W has few surfaces that can be in close contact with each other or is slippery “a stuffed toy with many irregularities and a surface covered with hair”.

  FIG. 6 is another conceptual cross-sectional view of a gripping method using the gripping device 10 of the first embodiment. In this example, the workpiece W is assumed to be an egg (raw egg, boiled egg) that is fragile with non-uniform external force.

5 and 6, the core member 14 is a rigid body whose outer dimension does not change due to a change in the internal pressure of the gripping bag 16.
Further, the particles 18 are foamed resin (for example, polystyrene foam) and have a repulsive force that returns to its original shape when contracted.

FIG. 5A shows a state where the gripping device 10 shown in FIG. 2 is positioned on the workpiece W with the pressure receiving surface 12a facing downward. In this state, the inside of the gripping bag 16 communicates with the outside through a filter (not shown) so that the gas (for example, air) in the upper space can be exhausted to the outside.
The same applies to the case where the workpiece W is an egg that is easily broken by external force.
In this state, the gripping bag 16 has a spherical shape, but may be deformed from a spherical shape due to the weight of the granules 18 inside.

FIG. 6A corresponds to FIG.
In the gripping method of the present invention, as shown in FIGS. 5 (B) and 6 (A), the lower end of the core member 14 with the pressure receiving surface 12a facing downward and the inside of the gripping bag 16 communicating with the outside. The gripping device 10 is moved until it approaches the workpiece W. Accordingly, a part of the gripping device 10 is positioned around the workpiece W and is lower than the upper portion of the workpiece W.
Therefore, by making the lower end of the core member 14 close to the workpiece W, the core member 14 whose central portion protrudes downwardly surrounds at least a part of the workpiece W using the fluidity of the particles 18. The particles 18 are moved inside the gripping bag 16. At this time, the workpiece W and the gripping bag 16 may not be in close contact with each other.

  During the movement of the particles, there is a space inside the gripping bag 16 and the particles 18 can flow. Therefore, when the lower surface of the gripping bag 16 is recessed so as to surround the workpiece W, the inner particles 18 Can flow freely without being compressed. Further, since the core member 14 does not come into contact with the workpiece W, only a part of the weight of the whole granule acts on the workpiece W. Therefore, even if the workpiece W is fragile (eg, an egg) with non-uniform external force, the breakage can be reduced or prevented.

FIG. 6B corresponds to FIG.
Next, as shown in FIGS. 5C and 6B, the inside of the gripping bag 16 is depressurized and contracted. Thereby, the space | gap between granules is reduced and it adheres mutually, and the workpiece | work W is hold | gripped from the side by the lump (granule lump) of the granule 18 shape | molded by the frictional force between the granules.
In this example, the gripping force of the workpiece W can be increased by the repulsive force of the granules themselves.

  During the decompression, the lower end of the core member 14 is close to the workpiece W, and the ratio of the particles 18 that do not surround the workpiece W is small. Therefore, the portion surrounding the workpiece W can be sufficiently solidified.

At this time, the lump of the particles 18 (granule lump) shrinks as a whole from the state surrounding at least a part of the workpiece W, so that the contact area with the workpiece W is large and the contact pressure of the contact surface is low.
Furthermore, since this surface pressure is proportional to the difference between the internal pressure of the gripping bag 16 and the atmospheric pressure during decompression, it can be variably controlled by adjusting the internal pressure during decompression.

Further, since the gripping bag 16 is uneven at the time of this pressure reduction, the workpiece W is easily caught.
Further, since the gripping bag 16 is deformed and wraps the workpiece W, it is not necessary to make close contact.

  Therefore, even if the workpiece W has a small surface that can be closely contacted (for example, “stitched”) or is easily broken by an external force (for example, egg), the workpiece W can be securely and safely gripped. Can do.

  In the state of FIG. 5C and FIG. 6B, the workpiece W can be gripped using the gripping device 10 of the present invention, and the workpiece W can be transported to another position by the transport robot 1.

  At another position, that is, at the transfer destination, the internal pressure of the gripping bag 16 can be returned to the atmospheric pressure and the work W can be released in a state where the work W of FIGS. 5C and 6B is gripped.

FIG. 7 is an explanatory diagram of the gripping device 10 according to the second embodiment and a gripping method using the same.
In FIG. 7A, the core member 14 is a hollow elastic bag that can be inflated by internal pressure.
Moreover, in this example, the pressurization apparatus 22 which can pressurize the inside of the core member 14 and can return to atmospheric pressure is further provided.
Other configurations are the same as those of the first embodiment.

The pressurizing device 22 expands the core member 14 by pressurizing the inside of the core member 14, and returns the pressure in the core member 14 to atmospheric pressure, thereby returning the core member 14 to its original size. It comes to return. In this example, the control device 26 described above also controls the pressurizing device 22.
In this example, the pressurizing device 22 is installed in the connecting portion 6, but may be in another place as long as these functions are not impaired.

  The state in FIG. 7A is the same as that in FIG.

In the gripping method of the present invention, as shown in FIG. 7B, the control member 26 presses the inside of the core member 14 while the inside of the gripping bag 16 is in communication with the outside. 14 is inflated.
By this expansion, the core member 14 can be set to a size suitable for the workpiece W.

  Next, the gripping device 10 is moved (lowered) until the lower end of the core member 14 comes close to the workpiece W. By moving the lower end of the core member 14 close to the workpiece W, the core member 14 whose central portion protrudes downward moves the granules 18 inside the gripping bag 16 so as to surround at least a part of the workpiece W. .

  Next, as shown in FIG. 7C, the inside of the gripping bag 16 is depressurized and contracted. Thereby, the space | gap between granules is reduced and it adheres mutually, and the workpiece | work W is hold | gripped from the side by the lump (granule lump) of the granule 18 shape | molded by the frictional force between the granules.

In the state of FIG. 7C, the workpiece W is gripped using the gripping device 10 of the present invention, and the workpiece W is transported to another position by the transport robot 1. Further, at another position, that is, at the conveyance destination, the internal pressure of the gripping bag 16 is returned to the atmospheric pressure while the work W in FIG. 7C is gripped, and the work W is released.
At this time, the internal pressure of the core member 14 may be maintained in a pressurized state or may be returned to atmospheric pressure.

FIG. 8 is a conceptual cross-sectional view of the gripping device 10 of the third embodiment and a gripping method using the same.
In this example, the core member 14 is a rigid body whose outer dimension does not change due to a change in the internal pressure of the gripping bag 16.

  Further, in this example, a breathable hollow granule bag 24 housed in the gripping bag 16 is further provided. The hollow particle bag 24 is an annular bag (in this example, a donut shape) that accommodates the particles 18 therein. The hollow particle bag 24 may be a woven fabric or a net through which the particles 18 cannot pass. Moreover, it is good for the hollow particle bag 24 to have a stretching property.

In this example, the hollow granule bag 24 has an opening 24a capable of accommodating at least a part of the workpiece W at the center of the bag body.
The opening 24a is preferably a hemispherical opening (a mouth in which the contact portion with the surface is circular), but the contact portion with the surface may be an elliptical or rectangular opening.
Other configurations are the same as those of the first embodiment.

The state in FIG. 8A is the same as that in FIG.
That is, FIG. 8A shows a state in which the pressure receiving surface 12a faces downward and the gripping device 10 is positioned above the workpiece W. In this state, the inside of the gripping bag 16 communicates with the outside through a filter (not shown) so that the gas (for example, air) in the upper space can be exhausted to the outside.
The same applies to the case where the workpiece W is an egg that is easily broken by external force.
In this state, the gripping bag 16 has a spherical shape, but may be deformed from a spherical shape due to the weight of the granules 18 inside.

In the gripping method of the present invention, as shown in FIG. 8B, the lower end of the core member 14 is close to the workpiece W with the pressure receiving surface 12a facing downward and the inside of the gripping bag 16 communicating with the outside. Until the gripping device 10 is moved (lowered). By moving the lower end of the core member 14 close to the workpiece W, the core member 14 whose central portion protrudes downward moves the granules 18 inside the gripping bag 16 so as to surround at least a part of the workpiece W. .
At this time, by accommodating the workpiece W in the opening 24 a of the hollow particle bag 24, the particles 18 inside the hollow particle bag 24 can be easily moved around the workpiece W.

  Next, as shown in FIG. 8C, the inside of the gripping bag 16 is depressurized and contracted. Thereby, the space | gap between granules is reduced and it adheres mutually, and the workpiece | work W is hold | gripped from the side by the lump (granule lump) of the granule 18 shape | molded by the frictional force between the granules.

  In the state of FIG. 8C, the workpiece W is gripped using the gripping device 10 of the present invention, and the workpiece W is transported to another position by the transport robot 1. Further, at another position, that is, at the transfer destination, the internal pressure of the gripping bag 16 is returned to the atmospheric pressure while the work W in FIG. 8C is gripped, and the work W is released.

  According to the present invention described above, the core member 14 protrudes into the gripping bag. Further, the granules 18 are accommodated in the gripping bag 16 so as to be able to flow while leaving a space. Further, the particles 18 occupy a total volume surrounding at least a part of the workpiece W.

  Accordingly, by moving (lowering) the gripping device 10 until the lower end of the core member 14 comes close to the workpiece W in a state where the pressure receiving surface 12a faces downward and the inside of the gripping bag 16 communicates with the outside, the gripping bag 10 The particles 18 can be moved inside the workpiece 16 so as to surround at least a part of the workpiece W.

  During the movement of the particles, there is a space inside the gripping bag 16 and the particles 18 can flow. Therefore, when the lower surface of the gripping bag 16 is recessed so as to surround the workpiece W, the inner particles 18 Can flow freely without being compressed, and the core member 14 does not come into contact with the work W, so that only a part of the weight of the whole granule acts on the work W.

Next, the inside of the gripping bag 16 is depressurized and contracted, thereby reducing gaps between the particles and bringing them into close contact with each other, and by a lump (granule lump) of the particles 18 formed by the frictional force between the particles. The workpiece W can be gripped from the side.
During the decompression, the lower end of the core member 14 is close to the workpiece W, and the ratio of the particles 18 that do not surround the workpiece W is small. Therefore, the portion surrounding the workpiece W can be sufficiently solidified.

  At this time, the lump of the particles 18 (granule lump) shrinks as a whole from the state surrounding at least a part of the workpiece W, so that the contact area with the workpiece W is large and the contact pressure of the contact surface is low. Furthermore, since this surface pressure is proportional to the difference between the internal pressure of the gripping bag 16 and the atmospheric pressure during decompression, it can be variably controlled by adjusting the internal pressure during decompression.

  Accordingly, the gripping device 10 of the transfer robot 1 according to the present invention can securely and safely grip the workpiece W having no contactable surface and the workpiece W that is easily broken by an external force.

In addition, this invention is not limited to embodiment mentioned above, is shown by description of a claim, and also includes all the changes within the meaning and range equivalent to description of a claim.
Further, although the core member 14 is described as being fixed to the fixing member 12, a similar effect can be expected even with a member that is not fixed as long as the density is lower than that of the granule and does not sink into the granule.

W Workpiece (object to be gripped), C1, C2, C3, C4 Rotating axis, 1 Transfer robot, 2a, 2b, 2c Robot arm, 3 Robot hand, 4 Robot support, 5a, 5b, 5c Joint, 6 Connection Part, 7 work container, 10 gripping device, 12 fixing member, 12a pressure receiving surface, 14 core member, 16 gripping bag, 16a depression, 18 granule, 20 decompression device, 22 pressurization device, 24 hollow granule bag, 24a opening, 26 control device

Claims (5)

A fixing member having a pressure receiving surface;
A core member fixed to the center of the pressure receiving surface;
A hollow gripping bag that is attached to the pressure-receiving surface so as to surround the core member, has airtightness, and is deformable.
Granules accommodated in the gripping bag so as to be flowable leaving a space inside;
A decompression device capable of decompressing and contracting the inside of the gripping bag and returning the pressure to atmospheric pressure,
The core member protrudes into the gripping bag;
The said granule is a holding | grip apparatus which occupies the total volume surrounding at least one part of a workpiece | work. Comprising a breathable hollow granule bag housed inside the gripping bag,
The gripping device according to claim 1, wherein the hollow granular bag is an annular bag that accommodates the granular substance therein, and has an opening capable of accommodating at least a part of the workpiece at a center of the bag. .   The gripping device according to claim 1, wherein a shape of the core member is a spherical shape, a hemispherical shape, a cone shape, a prefix cone shape, or a rod shape.   The gripping device according to claim 1, wherein the gripping bag has a recess recessed inwardly on an outer surface thereof. A gripping method using the gripping device according to claim 1,
(A) In a state where the pressure receiving surface is faced down and the inside of the gripping bag communicates with the outside, the gripping device is moved until the lower end of the core member is close to the workpiece, thereby Move the particles inside so as to surround at least a part of the workpiece,
(B) Next, the inside of the gripping bag is depressurized and contracted, thereby reducing the gaps between the particles and bringing them into close contact with each other, and the workpiece is formed by the lump of particles formed by the frictional force between the particles. A gripping method for gripping from the side.

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