JP7450981B2 - robot hand - Google Patents

Description

The present invention relates to a robot hand.

The mechanism for gripping an object with a robot hand includes a gripping section that has a flexible and airtight hollow bag filled with powder, and a mechanism that reduces the pressure in the interior space of the hollow bag to a predetermined negative pressure. A suction gripper equipped with a pressure reducing device capable of returning the pressure to atmospheric pressure is known (see Japanese Patent Laid-Open No. 2012-176476).

In this suction gripper, when the hollow bag is pressed against an object while the internal space is at atmospheric pressure, the contact portion deforms to follow the shape of the object. In this state, when the internal space of the hollow bag is reduced to negative pressure, a force is generated that presses the particles together, causing them to solidify (jamming dislocation). This jamming dislocation allows the hollow bag to adsorb to the object and lift the object. After the object has been moved to a desired position, the internal space of the hollow bag is returned to atmospheric pressure to release the adsorption and separate the suction gripper from the object.

Japanese Patent Application Publication No. 2012-176476

Although this suction gripper can grip an object regardless of its shape or size, it is difficult to recognize various gripping states of the object. For example, if a sensor or the like is embedded in the surface of a hollow bag, the flexibility of the hollow bag may be insufficient and the grip strength of the object may be reduced. Furthermore, when grasping an object, the object is often located in a blind spot of the hollow bag, making it difficult to confirm it using images or the like.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a robot hand that can easily recognize the grasping state of an object while using jamming dislocation.

The present invention provides a robot hand capable of gripping an object, comprising: a base plate; a deformable bag body having an opening attached to one side of the base plate; A detection unit that determines the grasping state of the object by electrically or magnetically detecting the powder filled inside the body and the uneven distribution of the powder; and a detection unit that decompresses the inside of the bag. and a suction device.

The robot hand of the present invention can easily recognize the grasping state of an object while using jamming dislocation.

FIG. 1 is a schematic exploded perspective view showing the configuration of a robot hand according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the robot hand in FIG. 1. FIG. 3 is a schematic cross-sectional view showing a state in which the robot hand in FIG. 2 is in contact with an object. FIG. 4 is a schematic cross-sectional view showing a state in which the robot hand in FIG. 3 grips an object. FIG. 5 is a schematic cross-sectional view showing a state in which the robot hand in FIG. 4 lifts an object. FIG. 6 is a schematic cross-sectional view of a robot hand according to an embodiment different from FIG. 2. FIG. 7 is a schematic cross-sectional view of a robot hand according to an embodiment different from FIGS. 2 and 6. FIG. FIG. 8 is a schematic exploded perspective view of a robot hand according to an embodiment different from FIGS. 2, 6, and 7. FIG. 9 is a schematic cross-sectional view of the robot hand of FIG. 8. FIG. 10 is a schematic cross-sectional view showing a state in which the robot hand in FIG. 9 lifts an object. FIG. 11 is a schematic cross-sectional view of a robot hand according to an embodiment different from FIGS. 2, 6, 7, and 9. FIG. 12 is a schematic cross-sectional view of a robot hand according to an embodiment different from FIGS. 2, 6, 7, 9, and 11. FIG. 13 is a schematic cross-sectional view of a robot hand according to an embodiment different from FIGS. 2, 6, 7, 9, 11, and 12. FIG. 14 is a schematic cross-sectional view showing the shape of the test piece used in the example. FIG. 15 is a graph showing the relationship between pressing force and sensor value in an embodiment of a robot hand that recognizes the gripping state using resistance values. FIG. 16 is a graph showing the relationship between pressing force and sensor value in an embodiment of a robot hand that recognizes a grip state using a capacitance value. FIG. 17 is a graph showing the effect of insulating powder in an embodiment of a robot hand that recognizes the grip state using resistance values. FIG. 18 is a graph showing the effect of the pouch body in the embodiment of the robot hand that recognizes the grip state using the resistance value.

[Description of embodiments of the present invention]
First, embodiments of the present invention will be listed and explained.

The present invention provides a robot hand capable of gripping an object, comprising: a base plate; a deformable bag body having an opening attached to one side of the base plate; A detection unit that determines the grasping state of the object by electrically or magnetically detecting the powder filled inside the body and the uneven distribution of the powder; and a detection unit that decompresses the inside of the bag. and a suction device.

The robot hand can adsorb or detach an object from the deformable bag using jamming dislocation of the powder filled inside the bag. Further, in the robot hand, since the powder has conductivity, the electrical and magnetic properties of the powder as a whole change due to the uneven distribution of the powder that occurs when the object is gripped. In the robot hand, the state in which the object is gripped can be easily recognized by electrically or magnetically detecting the uneven distribution of the powder using the detection section.

The detection unit has a plurality of electrodes provided spaced apart inside the bag, and uses a resistance value between a plurality of pairs of electrodes selected from the plurality of electrodes to detect uneven distribution of the powder. Good. By gripping an object, a dent is formed on the surface of the bag, following the object. Powder is unevenly distributed depending on the shape of this concave portion, and its bulk density changes. As a result, a change occurs in the resistance value between the plurality of pairs of electrodes. Therefore, by using the resistance value between the plurality of pairs of electrodes, it is possible to detect the change in the bulk density and detect the uneven distribution of powder. Further, since the resistance value can be realized by inserting a plurality of electrodes into the bag, the detection section can be easily constructed.

The detection unit includes a plurality of bag-shaped dielectric films provided inside the bag, a first electrode provided inside each of the plurality of dielectric films, and an outside of the dielectric film provided with the first electrode. and a second electrode provided inside the bag, and a capacitance value between the first electrode and the second electrode may be used to detect uneven distribution of the powder. The change in bulk density due to uneven distribution of the powder can also be detected as a change in capacitance value. In a robot hand using jamming dislocation, in order to prevent the powder from being biased towards the lower side of the base plate when the base plate is tilted, the inside of the bag is partitioned and divided into small rooms. The body may be distributed. When detecting the uneven distribution of the powder based on changes in capacitance, it is necessary to cover the first electrode with a dielectric film to prevent short circuits between the first and second electrodes. In a bag that is divided into small rooms, this can be realized by using a dielectric film as the partition and inserting an electrode into each small room, so that the detection section can be easily constructed.

The detection unit includes a plurality of electromagnetic induction proximity sensors fixed to the base plate at a distance, and changes in impedance of a detection coil of the plurality of electromagnetic induction proximity sensors is used to detect uneven distribution of the powder. It is recommended to use When the bag is pressed against an object to grip the object, the conductive powder moves as the contact portion deforms to follow the shape of the object. The electromagnetic induction type proximity sensor can detect the magnetic change caused by the movement of the conductive powder by the impedance change of the detection coil. The detection unit can detect uneven distribution of the powder from movement of the powder. Since the electromagnetic induction type proximity sensor can detect the movement of the powder from outside the bag, there is no need to insert a measuring member inside the bag. Therefore, the detection section is less likely to affect the movement of the powder, and the gripping force of the object is less likely to decrease.

The bag has a chamber that covers the other side of the base plate and is capable of storing the powder therein, and the bag has a partition wall that divides the inside of the bag into a plurality of small chambers into which the powder cannot be moved. , the small chamber is in contact with the base plate, the base plate has a through hole that communicates each small chamber with the inside of the chamber, and through which the powder can pass, and the powder is in contact with the base plate. It is preferable to be able to freely move between the small rooms via the chamber. By dividing the bag into small rooms in this way, it is possible to prevent the powder from being biased towards the lower side of the base plate when the base plate is tilted. In addition, since the powder can freely move between the small rooms via the chamber, the bag deforms by grasping the object, and the powder is transferred from the small room with a narrow space to the chamber. If the body moves and a small room with a larger space is created, the powder will move from the chamber to that small room. In this way, by allowing the powder to freely move back and forth between the small chambers via the chamber, the object can be gripped while keeping the bulk density of the powder constant, thereby increasing the gripping force. Furthermore, since the amount of powder is reduced in the part where the object is gripped, electrical or magnetic changes due to uneven distribution of powder tend to become large, and uneven distribution of powder can be detected more reliably.

The bag further includes an insulating powder filled inside the bag, wherein the content of the powder is 20% by mass or more and 45% by mass or less based on the total of the conductive powder and the insulating powder. It would be good if it were. By mixing the powder and insulating powder in the bag so that the powder content is within the above range, it is easy to detect uneven distribution of the powder in the bag in stages. Become.

It is preferable that the bag has a plurality of small bags inside thereof, and each of the small bags is filled with the powder. By dividing the inside of the bag into small bags and filling the inside with the powder, it is possible to prevent the powder from being extremely unevenly distributed due to the tilt of the robot hand. Therefore, the grip state of the object can be more easily recognized.

Note that "having electrical conductivity" means that the volume resistivity value measured in accordance with JIS-H-0505 (1975) is 10 ⁷ Ω·cm or less.

[Details of embodiments of the present invention]
DESCRIPTION OF THE PREFERRED EMBODIMENTS The robot hand according to each embodiment of the present invention will be described below with reference to the drawings as appropriate.

[First embodiment]
A robot hand 1 shown in FIGS. 1 and 2 is a robot hand that can grip an object X. The robot hand 1 includes a base plate 10, a deformable bag 20 whose opening is attached to one side of the base plate 10, and an electrically conductive bag 20 that is filled with a conductive material. It includes a powder 30 and a detection unit 40 that grasps the grip state of the object X by electrically detecting the uneven distribution of the powder 30. The robot hand 1 also includes a suction device (not shown) that reduces the pressure inside the bag 20 and the cavity in the center of the bag 20.

The robot hand 1 is attached to the tip of a movable arm, for example, and can grip and move the object X.

<Base plate>
The base plate 10 is a fixing member that fixes the bag body 20. The base plate 10 may have flexibility, but preferably does not have flexibility.

As the material of the base plate 10, metal such as aluminum, resin such as plastic, wood, etc. can be used.

Although the shape of the base plate 10 in plan view is not particularly limited, it may be circular as shown in FIG. 1, for example. By making the base plate 10 circular, the robot hand 1 has no anisotropy, so there is no need to consider the direction in which the object X is gripped, and the handleability is improved. The size of the base plate 10 is appropriately determined depending on the size of the object X to be gripped, etc., but when the base plate 10 is circular, its diameter can be, for example, 1 cm or more and 500 cm or less.

The base plate 10 also has a vacuum suction port 11 connected to the central cavity of the bag body 20 and a bag internal suction port 12 connected to the inside of the bag body 20. These suction ports are through holes, and are connected to a suction device through piping or the like on the back side of the base plate 10.

<Bag body>
As shown in FIG. 1, the bag body 20 includes a bag body 21 and a restraining plate 22.

The bag main body 21 is made of a flexible membrane. Thereby, the bag body 20 becomes deformable. As the membrane, a silicone membrane, an elastomer membrane made from natural rubber, latex rubber, or the like can be used.

Preferably, the film has insulating properties. Since the film, that is, the bag main body 21 has insulating properties, it is possible to easily detect changes in the resistance value due to uneven distribution of the powder 30.

The shape of the bag main body 21 (the shape in a state where it hangs down from the base plate 10) is not particularly limited. For example, the bag main body 21 shown in FIG. 1 has a hollow in the center and has a circular horizontal cross section, that is, a donut shape. The size of the bag main body 21 is appropriately determined depending on the size of the object X to be gripped, etc., but for example, in the case of the bag main body 21 shown in FIG. The height can be 10 cm or more and 30 cm or less, and the diameter of the cavity can be 5 cm or more and 10 cm or less. When the bag main body 21 has a doughnut-like shape as described above, it is possible to reduce the pressure (vacuum suction) in the central cavity. By reducing the pressure in the cavity, the attraction force for the object X can be improved. On the other hand, the bag main body 21 may have a simple bag shape. By making the shape of the bag body 21 into a simple bag shape in this way, the gripping force due to jamming dislocation can be increased.

The restraining plate 22 is a fixing member for sandwiching and fixing the opening side end of the bag main body 21 between it and the base plate 10. In addition, in the robot hand 1 of FIG. 1, the bag body 21 is fixed using the holding plate 22, but the method of fixing the bag body 21 is not limited to this. For example, instead of the holding plate 22, a spring or a string may be used. You may also use a method of fastening with, etc.

The material of the restraining plate 22 can be the same as that of the base plate 10. Further, as shown in FIG. 1, the shape of the holding plate 22 may be a ring shape having an outer diameter equal to that of the base plate 10 and an average width of 1 cm or more and 5 cm or less.

<Powder>
The powder 30 is an aggregate of particles.

The material of the powder 30 is not particularly limited as long as it is conductive and strong enough not to be damaged by contact between particles when the inside of the bag 20 is depressurized, but for example, metal can be used. Examples of the metal include aluminum, zinc, gold, silver, copper, iron, manganese, and the like.

Moreover, piezo powder can also be used as the powder 30. The conductivity of piezo powder changes when pressure is applied. As will be described later, the pressure applied to the powder 30 located at the portion where the bag 20 is pushed up by the object X is greater than at other locations. By using piezo powder as the powder 30, the resistance value of the powder 30 can be changed between a position where the pressure is high, that is, where the object X is present, and a position where the pressure is low, that is, where the object X is not present. Since it can be changed, the grip state of the object X can be more easily recognized.

The lower limit of the average particle diameter of the particles is preferably 1 μm, more preferably 10 μm, and even more preferably 100 μm. On the other hand, the upper limit of the average particle diameter of the particles is preferably 1500 μm, more preferably 1000 μm. When the average particle diameter of the particles is less than the lower limit, the bulk density of the powder becomes too large, and there is a possibility that the bag 20 will be difficult to change to follow the shape of the object X. On the other hand, if the average particle diameter of the particles exceeds the upper limit, the gaps between the particles may not be sufficiently filled when the inside of the bag 20 is depressurized, and the gripping force may be reduced. Here, the "average particle size" refers to the sieve opening at which the mass integrated value is 50% in the particle size distribution determined by a dry sieving test using a sieve specified in JIS-Z-8801 (2006). means.

The lower limit of the filling rate of the powder 30 into the bag body 20 is preferably 70% by volume, more preferably 75% by volume. On the other hand, the upper limit of the filling rate is preferably 85% by volume, more preferably 80% by volume. If the filling rate is less than the lower limit, the amount of air will increase, so it will take time to reduce the pressure, and there is a risk that the working efficiency of the robot hand 1 will decrease. On the other hand, if the filling rate exceeds the upper limit, the space in which the particles constituting the powder 30 can move becomes too narrow, which may make it difficult for the bag 20 to follow the shape of the object X and change. Here, the "filling rate of powder into the bag" refers to the ratio of the volume of the powder 30 to the volume of the bag 20 in a state suspended from the base plate 10.

<Detection part>
The detection unit 40 has a plurality of electrodes 41 provided spaced apart inside the bag body 20. In the robot hand 1, the resistance value between multiple pairs of electrodes 41 selected from the multiple electrodes 41 is used to detect uneven distribution of the powder 30. That is, the detection unit 40 includes a measuring device (not shown) that measures the resistance between the electrodes 41.

The electrode 41 has conductivity and is configured such that at least a portion thereof is in contact with the powder 30. The material of the electrode 41 is not particularly limited as long as it has conductivity, but may be made of the same material as the powder 30, for example.

It is preferable that the electrode 41 has a spring shape so as not to inhibit the deformation of the bag body 20. At this time, it is preferable that the length (natural length) of the electrode 41 be such that its tip touches the bag body 20. By setting the length of the electrode 41 in this manner, uneven distribution of the powder 30 due to deformation near the tip of the bag body 20 can be easily detected.

The lower limit of the number of electrodes 41 is preferably three, more preferably five. On the other hand, the upper limit of the number of electrodes 41 is preferably 20, more preferably 15. If the number of electrodes 41 is less than the above lower limit, the number of resistance value measurement points will decrease, which may make it difficult to detect uneven distribution of powder 30. Note that in order to avoid a decrease in the number of resistance value measurement points, a method may be adopted in which measurement is performed while selecting any two electrodes 41 using a multiplexer. With this configuration, it is possible to secure measurement paths for the number of combinations in which two of the plurality of electrodes 41 are selected at most, so the number of electrodes 41 can be reduced and the electrodes 41 can be used as obstacles. It is also possible to prevent the deformation of the bag body 20 from being inhibited. On the other hand, if the number of electrodes 41 to be provided exceeds the above upper limit, there is a possibility that the deformation of the bag body 20 will be significantly inhibited. However, the number of electrodes 41 to be provided is determined as appropriate depending on the object X and the task performed by the robot hand 1, and does not prevent the number from exceeding the above-mentioned upper limit.

It is preferable that the plurality of electrodes 41 be arranged at approximately equal density with respect to the horizontal cross section of the bag body 20 in a state suspended from the base plate 10, that is, it is preferable that the electrodes 41 are not unevenly distributed. By arranging the plurality of electrodes 41 in this manner, uneven distribution of the powder 30 can be comprehensively detected.

In the robot hand 1, the detection unit 40 measures the resistance value between multiple pairs of electrodes 41 selected from the multiple electrodes 41. The combination of the plurality of pairs of electrodes 41 may be the entire combination of the plurality of electrodes 41 or a part thereof. When all combinations are used, uneven distribution of the powder 30 can be comprehensively detected. On the other hand, when some combinations are used, measurement efficiency can be improved. In addition, when using some combinations, it is preferable to determine the combinations so that the coverage of the area where the uneven distribution of the powder 30 can be detected from the measurement results is increased.

<Suction device>
A suction device (not shown) of the robot hand 1 is disposed, for example, at the base end of a movable arm.

The suction device is not particularly limited as long as it can reduce the pressure inside the bag 20 and the central cavity of the bag 20, and a known vacuum pump or the like can be used. The suction device, the vacuum suction port 11 of the base plate 10, and the bag internal suction port 12 are connected by piping or the like, and are configured to be capable of suctioning each independently.

The above-mentioned suction device is configured to suck the bag through the vacuum suction port 11 when the object X contacts the tip of the bag 20 and the object It is configured to be able to reduce the pressure in the cavity in the center of the body 20. When the pressure in the central cavity of the bag 20 is reduced, a pressure difference is generated between the bag 20 side of the object X and the opposite side of the bag 20, and the object X is attracted to the bag 20. .

Further, the suction device is configured to be able to reduce the pressure inside the bag body 20 via the bag internal suction port 12 . When the inside of the bag 20 is depressurized, a jamming dislocation occurs and the robot hand 1 can grip the object X.

<Operating principle>
The principle by which the detecting unit 40 can detect the uneven distribution of the powder 30 along with the movement of the robot hand 1 to lift the object X will be explained using FIGS. 2 to 5.

As shown in FIG. 2, the robot hand 1 is controlled so as to contact the object X to be grasped from above. At this time, the bag 20 is suspended from the base plate 10, and the powder 30 is distributed approximately homogeneously until it comes into contact with the object X, so the resistance value between the plurality of pairs of electrodes 41 is It remains approximately constant regardless of the

The lower surface of the bag body 20 of the robot hand 1 is pushed up by the object X, as shown in FIG. Since the bag body 20 is deformable, it deforms to follow the shape of the object X, wraps around the outside of the object X, and wraps around the object X. At this time, the powder 30 is pushed upward inside the bag 20, and due to the deformation of the bag 20, the space above the object X in the bag 20 becomes narrower, so the bulk density of the powder 30 increases. . In other words, the powder 30 is unevenly distributed above the object X. Since the powder 30 has conductivity, the resistance value decreases as the bulk density increases. Therefore, the resistance value between the electrodes 41 including the upper part of the object X in the current path decreases according to the average height at which the bag body 20 is lifted by the object X. Therefore, from the amount of change in resistance value between the plurality of pairs of electrodes 41, the average height at which the bag 20 is lifted by the object X between the electrodes 41 can be determined. Then, by composing the above average heights between the plurality of pairs of electrodes 41, the grasping state of the object X can be grasped.

With the bag 20 encasing the object X in this manner, the inside of the bag 20 is depressurized by the suction device. Then, as shown in FIG. 4, a force is generated that presses the particles together, resulting in solidification (jamming dislocation). Even in this state, since the uneven distribution of the powder 30 is maintained, it is possible to grasp the grasping state of the object X from the difference in resistance value between the plurality of pairs of electrodes 41 in the same way as before the jamming dislocation. . Note that since the rigidity of the powder 30 is higher after the jamming dislocation, the response time until contact detection is accelerated and the spatial resolution is increased, making it easier to grasp the grip state of the object X.

When the jamming dislocation occurs, the bag body 20 becomes adsorbed to the object X, and as shown in FIG. 5, the object X can be lifted.

On the other hand, when the object X adsorbed to the bag body 20 is to be released, the procedure opposite to that described above is followed. In other words, starting from the state of FIG. 5, as shown in FIG. 4, the suctioned object (Figure 3). Then, the suction of the bag 20 is released, and even if the bag 20 is lifted upward, the object X remains in place (FIG. 2).

<Advantages>
The robot hand 1 can adsorb or detach the object X from the bag 20 using jamming dislocation of the powder 30 filled inside the deformable bag 20. Further, in the robot hand 1, since the powder 30 has conductivity, the electrical and magnetic properties of the entire powder 30 change due to the uneven distribution of the powder 30 that occurs when the object X is gripped. In the robot hand 1, the state in which the object X is gripped can be easily recognized by electrically or magnetically detecting the uneven distribution of the powder 30 using the detection unit 40.

More specifically, in the robot hand 1, by gripping the object X, a dent is created in the surface of the bag body 20 following the object X. The powder 30 is unevenly distributed depending on the shape of this recessed portion, and its bulk density changes. As a result, the resistance value between the plurality of pairs of electrodes 41 changes. Therefore, by using the resistance value between the plurality of pairs of electrodes 41, it is possible to detect the change in the bulk density and detect the uneven distribution of the powder 30. Further, since the resistance value can be realized by inserting a plurality of electrodes 41 into the bag body 20, the detection section 40 can be easily configured in the robot hand 1.

[Second embodiment]
The robot hand 2 shown in FIG. 6 is a robot hand that can grasp an object. The robot hand 2 includes a base plate 10, a deformable bag 20 whose opening is attached to one side of the base plate 10, and an electrically conductive bag 20 that is filled with a conductive material. It includes a powder 30 and a detection unit 50 that detects the grip state of the object by electrically detecting the uneven distribution of the powder 30. Further, the robot hand 1 includes a suction device (not shown) that reduces the pressure inside the bag body 20.

The robot hand 2 is attached to the tip of a movable arm, for example, and can grasp and move an object. The configuration of the robot hand 2 other than the detection section 50 can be configured similarly to the robot hand 1 of the first embodiment. Therefore, the components other than the detection unit 50 are given the same reference numerals and the description thereof will be omitted.

<Detection part>
The detection unit 50 includes a plurality of bag-shaped dielectric films 51 provided inside the bag body 20, a first electrode 52 provided inside each of the plurality of dielectric films 51, and a dielectric film provided with the first electrode 52. 51 and a second electrode 53 provided inside the bag body 20. The robot hand 2 uses the capacitance value between the first electrode 52 and the second electrode 53 to detect uneven distribution of the powder 30. That is, the detection unit 50 includes a measuring device (not shown) that measures the capacitance value between the first electrode 52 and the second electrode 53.

The dielectric film 51 prevents the first electrode 52 and the second electrode 53 from being short-circuited via the powder 30. The dielectric film 51 is not particularly limited as long as it has insulating properties, but it is preferably flexible and deformable together with the bag body 20. Therefore, it is preferable that the dielectric film 51 is made of the same material as the bag body 21.

The inside of the bag-shaped dielectric film 51 is preferably filled with powder 30 . By filling the powder 30 in this way, even if the base plate 10 is tilted, a part of the powder 30 remains inside the dielectric film 51. Therefore, even if the base plate 10 is in an inclined state, the object can be gripped.

Although the number of dielectric films 51 to be provided depends on the configurations of the first electrode 52 and the second electrode 53, the lower limit of the number of dielectric films 51 to be provided is preferably three, and more preferably five. On the other hand, the upper limit of the number of dielectric films 51 is preferably 20, more preferably 15. If the number of dielectric films 51 is less than the above lower limit, the number of capacitance measurement points will decrease, which may make it difficult to detect uneven distribution of powder 30. Conversely, if the number of dielectric films 51 exceeds the above upper limit, deformation of the bag body 20 may be significantly inhibited.

The first electrode 52 and the second electrode 53 can be configured similarly to the electrode 41 of the first embodiment.

In measuring the capacitance value, it is sufficient that the first electrode 52 and the second electrode 53 are partitioned by at least one dielectric film 51 . Therefore, a plurality of first electrodes 52 may be provided inside one bag-shaped dielectric film 51. Moreover, one second electrode 53 may be provided in common to the plurality of dielectric films 51 on which the first electrodes 52 are provided. Alternatively, the first electrode 52 provided inside another dielectric film 51 can also be used as the second electrode 53.

<Operating principle>
The principle of operation of the robot hand 2 to lift an object is the same as that of the robot hand 1 of the first embodiment.

In the detection unit 50 of the robot hand 2, since the dielectric film 51 exists between the first electrode 52 and the second electrode 53, the first electrode 52 and the second electrode 53 are electrically insulated. There is. In this state, if the bulk density of the conductive powder 30 existing between the first electrode 52 and the second electrode 53 changes due to uneven distribution of the powder 30 above the object, the first electrode 52 and The capacitance value between the second electrode 53 changes. Therefore, in the robot hand 2, based on the amount of change in the capacitance value between the first electrode 52 and the second electrode 53, the bag is The average height at which 20 was lifted is known. Then, by composing the above average heights at each position, it is possible to grasp the grasping state of the object.

<Advantages>
In the robot hand 2, a change in bulk density due to uneven distribution of powder 30 can be detected as a change in capacitance value. In addition, in a robot hand in which the inside of the bag body 20 is partitioned into small rooms and the powder 30 is distributed, the partitions can be used as the dielectric film 51 and electrodes can be inserted into each small room. Since this can be realized, the detection unit 50 can be easily configured.

[Third embodiment]
The robot hand 3 shown in FIG. 7 is a robot hand that can grip an object. The robot hand 3 includes a base plate 10, a deformable bag 20 having an opening attached to one side of the base plate 10, and a conductive bag 20 filled with a conductive bag 20. It includes a powder 30 and a detection unit 60 that detects the grasping state of the object by electrically detecting the uneven distribution of the powder 30. Further, the robot hand 3 includes a suction device (not shown) that reduces the pressure inside the bag body 20.

The robot hand 3 is attached to the tip of a movable arm, for example, and can grip and move an object. The configuration of the robot hand 3 other than the detection section 60 can be configured similarly to the robot hand 1 of the first embodiment. Therefore, the components other than the detection unit 60 are given the same reference numerals and the description thereof will be omitted.

<Detection part>
The detection unit 60 includes a plurality of electromagnetic induction type proximity sensors 61 that are spaced apart and fixed to the base plate 10 . The robot hand 3 uses changes in the impedance of detection coils included in the plurality of electromagnetic induction proximity sensors 61 to detect uneven distribution of the powder 30.

The electromagnetic induction type proximity sensor 61 can detect the movement of individual particles of the conductive powder 30. Specifically, it operates on the following principle. In the electromagnetic induction type proximity sensor 61, a high frequency magnetic field is generated from a detection coil (primary coil). Due to electromagnetic induction that occurs when a conductor approaches this magnetic field, an induced current (eddy current) is generated in the conductor. This current changes the impedance of the detection coil (secondary coil) of the electromagnetic induction type proximity sensor 61. The movement of each particle of the powder 30 can be determined from this impedance change.

Since the electromagnetic induction type proximity sensor 61 can measure the movement of the conductor without contact, it can detect the movement of the powder 30 from outside the bag body 20. By measuring from the outside of the bag 20 in this way, it is possible to more reliably prevent the detection unit 60 from interfering with the deformation of the bag 20. On the other hand, the closer to the powder 30 that is the object of measurement, the more accurate measurement becomes possible. It is preferable to arrange it so that

The lower limit of the number of electromagnetic induction proximity sensors 61 is preferably three, more preferably five. On the other hand, the upper limit of the number of electromagnetic induction type proximity sensors 61 is preferably 20, more preferably 15. If the number of electromagnetic induction type proximity sensors 61 is less than the above lower limit, the number of measurement points for impedance changes will be small, which may make it difficult to detect uneven distribution of powder 30. Conversely, if the number of electromagnetic induction type proximity sensors 61 exceeds the above upper limit, the manufacturing cost of the robot hand 3 may become too high.

<Operating principle>
The principle of operation of the robot hand 3 to lift an object is the same as that of the robot hand 1 of the first embodiment.

In the robot hand 3, the uneven distribution of the powder 30 is detected by capturing the movement of the powder 30 that occurs when the lower surface of the bag 20 of the robot hand 3 is pushed up by an object. In other words, an object exists in a portion where the powder 30 is close to the electromagnetic induction type proximity sensor 61, and should have pushed the powder 30 up from below the bag body 20. Then, from the distance that the powder 30 has moved, the amount of movement of the surface where the bag 20 and the object are in contact can be determined. Therefore, since the shape of the contact surface can be specified, it is possible to grasp the grip state of the object.

<Advantages>
In the robot hand 3, the electromagnetic induction proximity sensor 61 can detect magnetic changes caused by the movement of the conductive powder 30 by changing the impedance of the detection coil. The detection unit 60 can detect uneven distribution of the powder 30 from the movement of the powder 30. Since the electromagnetic induction type proximity sensor 61 can detect the movement of the powder 30 from outside the bag 20, there is no need to insert a measuring member inside the bag 20. Therefore, the detection unit 60 is less likely to affect the movement of the powder 30, and the gripping force of the object is less likely to decrease.

[Fourth embodiment]
The robot hand 4 shown in FIGS. 8 and 9 is a robot hand that can grip the object Y. The robot hand 4 includes a base plate 70, a deformable bag 80 having an opening attached to one side of the base plate 70, and a conductive bag 80 filled with a conductive bag 80. The powder 30 and a detection unit 40 that detects the grasping state of the object Y by electrically detecting the uneven distribution of the powder 30, and a detection unit 40 that covers the other surface of the base plate 70 and contains the powder 30 inside. A retractable chamber 90 is provided. Further, the robot hand 4 includes a suction device (not shown) that reduces the pressure inside the bag body 80.

The robot hand 4 is attached to the tip of a movable arm, for example, and can grip and move the object Y. In the robot hand 4, the powder 30 and the detection unit 40 can be configured in the same manner as the robot hand 1 of the first embodiment, so the same reference numerals are given and the description thereof will be omitted.

<Base plate>
The base plate 70 is a fixing member that fixes the bag body 80. The base plate 70 has a through hole 71 that communicates the inside of the chamber 90 with each small room of the bag body 80 to be described later, and through which the powder 30 can pass. The base plate 70 can be configured in the same manner as the base plate 10 of the first embodiment except for having the through hole 71, so a detailed description thereof will be omitted.

<Bag body>
As shown in FIG. 9, the bag body 80 includes a bag body 81, a restraining plate 82, and a partition wall 83. Among these, the bag body 81 and the restraining plate 82 can be configured in the same manner as the bag body 21 and the restraining plate 22 of the bag body 20 of the first embodiment, so a detailed explanation will be omitted.

The partition wall 83 divides the inside of the bag body 81 into a plurality of small chambers into which the powder 30 cannot move. The small chambers are in contact with the base plate 70, and the powder 30 can freely move between the small chambers via the chamber 90. Further, the small rooms are partitioned so that a plurality of electrodes 41 are arranged in each room.

<Operating principle>
The principle by which the detection unit 40 can detect the uneven distribution of the powder 30 along with the movement of the robot hand 4 to lift the object Y will be explained using FIGS. 9 and 10.

Similar to the robot hand 1 of the first embodiment, the robot hand 4 is controlled so as to contact the object Y to be grasped from above. As a result, the lower surface of the bag 80 comes into contact with the object Y, and is pushed up by the object Y. Since the powder 30 filled in the small chamber pushed up at this time communicates with the chamber 90 through the through hole 71, it is pushed out toward the chamber 90 side. Further, in order to make the bulk density of the powder 30 uniform, the powder 30 is moved from the chamber 90 to a small room that is not pushed up by the object Y, and the bag body 80 is shaped so as to wrap around the object Y. transforms into In this state, the inside of the bag body 80 is depressurized by a suction device. Then, the powder 30 undergoes jamming dislocation. When the jamming dislocation occurs, the bag body 80 becomes adsorbed to the object Y, and as shown in FIG. 10, the object Y can be lifted.

In this case, since the bulk density of the powder 30 is made uniform inside the bag body 80, the resistance value above the object Y becomes high, and the resistance value above the object Y becomes high, and around the object Y (a position not above the object Y). Since the resistance value is low, the grip state of the object Y can be determined from the resistance value between the plurality of pairs of electrodes 41. Note that in the robot hand 4, since the interior of the bag 80 is divided into small rooms, the pairs of electrodes 41 are selected within the same small room.

<Advantages>
In the robot hand 4, by dividing the bag 80 into small rooms in this way, it is possible to prevent the powder 30 from being biased toward the lower side of the base plate 70 when the base plate 70 is tilted. In addition, since the powder 30 can freely move between the small rooms via the chamber 90, the bag 80 is deformed by grasping the object Y, and from the small room where the space is narrow, it is transferred to the chamber 90. If the powder 30 moves and a small room with a wider space is created, the powder 30 moves from the chamber 90 to that small room. By allowing the powder 30 to freely move between the small chambers via the chamber 90 in this way, the object Y can be gripped while keeping the bulk density of the powder 30 constant, thereby increasing the gripping force. In addition, since the amount of powder 30 is reduced in the part where the object Y is gripped, electrical or magnetic changes due to uneven distribution of powder 30 tend to increase, making it possible to detect uneven distribution of powder 30 more reliably. I can do it.

[Fifth embodiment]
The robot hand 5 shown in FIG. 11 is a robot hand that can grasp an object. The robot hand 5 includes a base plate 10, a deformable bag 20 whose opening is attached to one side of the base plate 10, and an electrically conductive bag 20 that is filled with a conductive material. The bag body 20 includes a powder 30, a detection unit 40 that detects the grasping state of an object by electrically detecting the uneven distribution of the powder 30, and an insulating powder 31 filled inside the bag body 20. . Further, the robot hand 5 includes a suction device (not shown) that reduces the pressure inside the bag body 20. Note that, in order to distinguish the conductive powder 30 from the insulating powder 31, the powder 30 will also be referred to as "conductive powder 30" hereinafter.

The robot hand 5 is attached to the tip of a movable arm, for example, and can grip and move an object. The robot hand 5 can be configured in the same manner as the robot hand 1 of the first embodiment except that it includes the insulating powder 31. Therefore, the components other than the insulating powder 31 are given the same reference numerals, and the description thereof will be omitted.

<Insulating powder>
The insulating powder 31 moderately inhibits conduction between the electrodes 41 when jamming dislocation occurs and the object is gripped by the robot hand 5, and the resistance value between the electrodes 41 is graded depending on the grip state. It plays the role of changing the situation. Therefore, the detection unit 40 can detect the uneven distribution of the conductive powder 30 with higher accuracy.

The material of the insulating powder 31 is not particularly limited as long as it has insulating properties and has strength that will not be damaged by contact between particles when the inside of the bag 20 is depressurized, but for example, resin can be used. .

The average particle diameter of the insulating powder 31 is preferably about the same as the average particle diameter of the conductive powder 30. Specifically, the average particle diameter of the insulating powder 31 is the same as that of the conductive powder 30. The lower limit of the ratio of average particle diameters is preferably 0.8, more preferably 0.9. On the other hand, the upper limit of the average particle diameter ratio is preferably 1.2, more preferably 1.1. When the ratio of the average particle diameters is less than the lower limit, the insulating powder 31 having a small particle diameter tends to accumulate below. On the other hand, if the ratio of the average particle diameters exceeds the upper limit, the conductive powder 30 having a small particle diameter tends to accumulate below. In either case, it may be difficult to mix the conductive powder 30 and the insulating powder 31.

The mass of the particles constituting the insulating powder 31 is preferably about the same as the mass of the particles constituting the conductive powder 30, and specifically, The lower limit of the particle mass ratio of the particles 31 is preferably 0.8, more preferably 0.9. On the other hand, the upper limit of the particle mass ratio is preferably 1.2, more preferably 1.1. When the ratio of the particle masses is less than the lower limit, the heavy conductive powder 30 tends to accumulate below. Conversely, when the ratio of the particle masses exceeds the upper limit, the heavy insulating powder 31 tends to accumulate below. In either case, it may be difficult to mix the conductive powder 30 and the insulating powder 31.

The lower limit of the sum of the filling rates of the conductive powder 30 and the insulating powder 31 (total filling rate) is preferably 70% by volume, more preferably 75% by volume. On the other hand, the upper limit of the total filling rate is preferably 85% by volume, more preferably 80% by volume. If the total filling rate is less than the lower limit, the amount of air will increase, so it will take time to reduce the pressure, and there is a risk that the working efficiency of the robot hand 5 will decrease. Conversely, if the total filling rate exceeds the upper limit, the space in which the particles constituting the conductive powder 30 and the insulating powder 31 can move becomes too narrow, causing the bag 20 to follow the shape of the object. It may become difficult to change.

The lower limit of the content of the conductive powder 30 relative to the total of the conductive powder 30 and the insulating powder 31 is preferably 20% by mass, more preferably 25% by mass. On the other hand, the upper limit of the content of the conductive powder 30 is preferably 45% by mass, more preferably 40% by mass. If the content of the conductive powder 30 is less than the lower limit, even when jamming dislocation occurs, there is no conduction between the electrodes 41, and there is a possibility that uneven distribution of the conductive powder 30 cannot be detected. On the other hand, if the content of the conductive powder 30 exceeds the upper limit, the effect of the insulating particles 31 in capturing the uneven distribution of the conductive powder 30 may be insufficient.

<Advantages>
In the robot hand 5, the conductive powder 30 and the insulating powder 31 are mixed in the bag so that the content of the conductive powder 30 is 20% by mass or more and 45% by mass or less. It becomes easy to grasp uneven distribution of the conductive powder 30 in stages.

[Sixth embodiment]
The robot hand 6 shown in FIG. 12 is a robot hand that can grip an object. The robot hand 6 includes a base plate 10, a deformable bag 20 whose opening is attached to one side of the base plate 10, and a conductive bag 20 that is filled with a conductive material. It includes a powder 30 and a detection unit 40 that detects the grasping state of the object by electrically detecting the uneven distribution of the powder 30. Further, the robot hand 6 includes a suction device (not shown) that reduces the pressure inside the bag body 20. In the robot hand 6, the bag body 20 has a plurality of small bags 23 therein, and each of the small bags 23 is filled with powder 30.

The robot hand 6 is attached to the tip of a movable arm, for example, and can grasp and move an object. The robot hand 6 can have the same configuration as the robot hand 1 of the first embodiment except that the bag body 20 has a plurality of small bags 23. Therefore, the components other than the pouch body 23 are given the same reference numerals and the description thereof will be omitted.

<Sack body>
The pouch body 23 can be made of a conductive or insulating film. When the pouch body 23 is made of a conductive film, the plurality of electrodes 41 forming the detection unit 40 can measure the resistance value between any two points as in the robot hand 1 of the first embodiment, The configuration of the detection unit 40 can be simplified. On the other hand, when the pouch body 23 is made of an insulating film, the detection unit 40 can only measure the resistance value between the electrodes 41 within the same pouch body 23. In other words, it is necessary to determine the size, number, and arrangement of the pouch bodies 23 so that it is easy to grasp the grip state of the object. However, in this configuration, since there is no conductive path passing through the surface of the membrane of the pouch body 23, it is easy to grasp the grasping state of the object from the obtained resistance value.

The plurality of small bags 23 may be configured to be in close contact with each other and in contact with the bag 20, but as shown in FIG. 12, the plurality of small bags 23 and the bag 20 may be configured to be spaced apart from each other. You can leave it there. When the plurality of small bags 23 and the bag 20 are configured to be spaced apart from each other, the powder 30 may also be filled in the outside area of the plurality of small bags 23 inside the bag 20. preferable.

Further, the plurality of small bags 23 and the area outside the plurality of small bags 23 inside the bag 20 are configured to be able to be sucked by the above-mentioned suction device.

The lower limit of the filling rate of the powder 30 into the pouch 23 is preferably 70% by volume, more preferably 75% by volume. On the other hand, the upper limit of the filling rate is preferably 85% by volume, more preferably 80% by volume. If the filling rate is less than the lower limit, the amount of air will increase, so it will take time to reduce the pressure, and there is a risk that the working efficiency of the robot hand 1 will decrease. On the other hand, if the filling rate exceeds the upper limit, the space in which the particles constituting the powder 30 can move becomes too narrow, which may make it difficult for the pouch body 23 to follow the shape of the object X and change.

<Advantages>
In the robot hand 6, the inside of the bag body 20 is divided into small bag bodies 23, and the powder 30 is filled inside the bag bodies 23. Since the powder 30 does not move beyond the pouch 23, even if the robot hand 6 is tilted, the powder 30 can be prevented from being extremely unevenly distributed within the pouch 20. Therefore, the robot hand 6 can more easily recognize the grip state of the object.

[Other embodiments]
The above embodiments do not limit the configuration of the present invention. Therefore, in the above embodiment, it is possible to omit, replace, or add the constituent elements of each part of the above embodiment based on the description of this specification and common general technical knowledge, and all of these are interpreted as falling within the scope of the present invention. Should.

In the above embodiment, as a method for electrically detecting the grip state of an object, a case where a resistance value is used and a case where a capacitance value is used are explained, but the electrical detection method is limited to these. It's not a thing. For example, it is also possible to use a piezoelectric material for the powder and recognize the grip state of an object from the change in electromotive force when pressure is applied. Alternatively, conductive particles having electromotive force due to the photoelectric effect can also be used. When using such conductive particles, it is possible to grasp the grip state of the object by converting the difference in light transmittance due to the density of the powder into an electromotive force. Furthermore, it is also possible to utilize the temperature dependence of the resistance value. When an object is gripped, there is usually a temperature difference between the object and the powder, and the temperature of the powder changes locally due to contact with the object. Due to the temperature dependence of the resistance value, it is possible to grasp the grip state of the object by capturing local changes in temperature.

Further, in the above embodiment, a case has been described in which an electromagnetic induction type proximity sensor is used as a method of magnetically detecting the grip state of an object, but the magnetic detection method is not limited to this. For example, it is also possible to use a method of detecting magnetic distortion when pressure is applied to powder using a Hall element or the like.

In the first embodiment described above, the tip of the electrode is in contact with the bag body, but as in the robot hand 7 shown in FIG. It does not need to be in a protruding position and not in contact with the bag body 20. In such a configuration, as shown in FIG. 5, the detection section 40 includes an insulating film 43 in addition to the plurality of electrodes 42. The insulating film 43 partitions the base plate 10 so that some of the plurality of electrodes 42 are on the outside and the remaining electrodes 42 are on the inside. Further, the insulating film 43 has a through hole 43a at a portion thereof, for example, at the tip. The powder 30 can move between the inside and outside of the insulating film 43 through this through hole 43a.

In this robot hand 7, the resistance value between a pair of electrodes 42 separated by an insulating film 43 is measured. Since the current path between the pair of electrodes 42 passes through the through hole 43a, even if the tips of the pair of electrodes 42 are not in contact with the bag body 20, the resistance value will depend on the shape of the bag body 20. and change. Therefore, the robot hand 7 can grasp the grip state of the object. Further, since the robot hand 7 does not need to make the electrode 42 long, it is possible to prevent the bag body 20 from becoming difficult to deform due to the electrode 42.

Note that although FIG. 13 shows a case where the detection section has one insulating film 43, a configuration in which a plurality of insulating films 43 are provided may be used. By devising a way to partition the plurality of electrodes 42, it becomes possible to measure resistance values from one electrode 42 to multiple electrodes 42 using different current paths, for example. In other words, since this one electrode 42 can be shared to detect a change in resistance value, the number of electrodes 42 can be reduced.

In the fifth and sixth embodiments described above, the detection section has a plurality of electrodes and the resistance value between the electrodes is used to detect uneven distribution of powder, but the detection section is limited to this configuration. It's not something you can do. For example, the detection unit may be configured to use a capacitance value as in the second embodiment, or be configured to use impedance changes of a detection coil of an electromagnetic induction proximity sensor as in the third embodiment, etc., respectively. It has the effect of

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Recognition of grip state based on resistance value]
We conducted an experiment to confirm that the state of grasping an object can be recognized based on changes in resistance while suppressing a decrease in grip strength.

<Example 1>
As Example 1, a robot hand shown in FIGS. 1 and 2 was prepared. A silicone membrane was used for the bag body. For the powder, aluminum facets passed through a sieve with an opening of 710 μm were used. Additionally, six spring-like electrodes were provided as electrodes.

<Comparative example 1>
As Comparative Example 1, a robot arm having the same configuration as Example 1 was prepared, except that it did not have an electrode and used coffee beans as the powder.

<Evaluation of grip strength>
In order to compare the gripping forces of Example 1 and Comparative Example 1, an experiment was conducted using the following procedure.

(Test pieces)
As shown in FIG. 14, the test piece Z is a base plate Z1 with a rectangular column Z2 (width W, height H; see FIG. 14) whose top surface is chamfered at both ends with a radius R (not shown). Got ready. Note that the width W, height H, and radius R of the prism Z2 are (W, H, R) = (0 mm, 0 mm, 0 mm), (30 mm, 1 mm, 0.1 mm), (40 mm, 2 mm, 0 Four types were prepared: .5mm) and (50mm, 3mm, 1mm). Note that (W, H, R) = (0 mm, 0 mm, 0 mm) means that the prism Z2 does not exist, that is, it is composed only of the base plate Z1, and in this case, the robot arm is composed of only the base plate Z1. will be lifted by suction.

(measurement)
The robot hand of Example 1 or Comparative Example 1 was pressed against each of the above test pieces using a low-speed cylinder ("PBDAS16X75-A" manufactured by KOGANEI) with a pressing force of 20N. Thereafter, adsorption was started by reducing the pressure inside the bag, and the test piece was lifted. The negative pressure (adsorption force) generated during this lifting was measured. Note that the measurement was performed five times, and the average value was taken as the measurement result. The results are shown in Table 1.

From the results in Table 1, it can be seen that the adsorption forces of Example 1 and Comparative Example 1 are equivalent. In other words, it can be said that the jamming transition can be effectively used even if the grip state is recognized by a change in resistance value.

<Recognition of grasping state>
Next, regarding Example 1, the recognition ability of the grip state was investigated using test pieces Z with (W, H, R) = (50 mm, 3 mm, 1 mm). Specifically, as shown in FIG. 14, the robot hand of Example 1 was pressed against the step of the test piece Z, and the pressing force and the sensor values at the three electrodes (the lower the resistance, the larger the value) ) was investigated. The results are shown in FIG.

In FIG. 15, sensor 1 and sensor 3 have electrodes on the convex part of test piece Z, and sensor 2 has an electrode at a position away from the convex part. From the graph of FIG. 15, the resistance value decreases (the sensor value increases) as the sensors 1 and 3 press against the sensor 2. From this, it can be seen that the object is gripped at the electrode positions of sensor 1 and sensor 3. Therefore, it can be said that the robot hand of Example 1 can recognize the grasping state of the object.

[Recognition of grip state based on capacitance value]
We conducted an experiment to confirm that the grip state can be recognized using capacitance values.

<Example 2>
As Example 2, a robot hand shown in FIG. 6 was prepared. A silicone film was used for the bag body and dielectric film. For the powder, aluminum facets passed through a sieve with an opening of 710 μm were used. Further, six spring-like electrodes were provided as the first electrode and the second electrode. Note that each spring-like electrode was provided inside the dielectric film.

<Recognition of grasping state>
Regarding this Example 2, the recognition ability of the grasping state was investigated using a test piece Z with (W, H, R)=(50 mm, 3 mm, 1 mm). Specifically, the robot hand of Example 2 was pressed against the step of the test piece Z, and the pressing force and the electrostatic charge when the pair of electrodes on the convex part of the test piece Z were used as the first electrode and the second electrode. The relationship with capacity was determined.

To measure capacitance, an RC circuit is configured with a 1MΩ resistance element and a capacitance element between the first and second electrodes, and the electrostatic capacitance is calculated from the time constant when a pulse is input to this RC circuit. The size of the capacity (sensor value) was evaluated. The results are shown in FIG. Note that the larger the sensor value, the larger the capacitance.

From the graph of FIG. 16, it can be seen that there is a correlation between pressing force and capacitance. From this, it can be said that the grip state can be recognized even by using the capacitance value.

[Effect of insulating powder]
An experiment was conducted to confirm the effectiveness of insulating powder.

A robot hand shown in FIG. 11 was prepared. A silicone membrane was used for the bag body. For the powder, aluminum facets passed through a sieve with an opening of 710 μm were used, and for the insulating powder, an insulating resin was used. Additionally, six spring-like electrodes were provided as electrodes.

The total amount of powder and insulating powder is fixed at 1 g, the proportion of aluminum powder is 100% by mass, 83% by mass, 50% by mass, 35% by mass, and 16% by mass, and the pressing force is 0 Pa. The sensor value at the electrode was investigated when the pressure was changed from 0.15 Pa to 0.15 Pa. The results are shown in FIG.

From the results in FIG. 17, it can be seen that when the proportion of powder is 35% by mass, a sensor value corresponding to the pressing force can be obtained. On the other hand, when the proportion of powder is 16% by mass, which is smaller than 20% by mass, there is no conduction between the electrodes even when jamming dislocation occurs, and uneven distribution of powder cannot be detected. On the other hand, if the proportion of powder exceeds 45% by mass, the sensor value immediately becomes 0 (low resistance conductive state) when pressing force is applied, making it impossible to detect uneven distribution of powder step by step. .

From the above, by mixing powder and insulating powder in the bag so that the powder content is 20% by mass or more and 45% by mass or less, it is possible to gradually grasp the uneven distribution of powder in the bag. It can be said that it becomes easier.

[Effects of multiple pouch bodies]
An experiment was conducted to confirm the effects of multiple pouch bodies.

A robot hand shown in FIG. 12 was prepared. Specifically, the robot hand has six pouch bodies, each of which has a pair of electrodes spaced apart from each other. A pair of electrodes contained in each pouch body are arranged at positions #1 to #6 in FIG. 18 when viewed from above of the robot hand. A silicone membrane was used for the bag body and the pouch body. Further, as the powder, an aluminum facet sieved through a sieve with an opening of 710 μm was used.

Furthermore, a robot hand that has an electrode at the same position as the robot hand shown in FIG. ) was prepared.

Using the robot hand with a pouch body and the robot hand without a pouch body, place the robot hand on a test piece (flat plate) with the robot hand tilted 15 degrees, that is, with the base plate of each robot hand tilted 15 degrees from the horizontal plane. It was pressed with a pressure of 20N, and the sensor values measured at each electrode were obtained. The results are shown in FIG.

From the results shown in Figure 18, when a robot hand without a pouch body is used, there are sensors that cannot detect uneven distribution of powder due to the inclination of the robot hand, whereas with a robot hand with a pouch body, all sensors detect uneven distribution of powder. has been detected. From the above, it can be seen that by using the robot hand with a pouch body, it is possible to prevent the powder from being extremely unevenly distributed due to the inclination of the robot hand.

As described above, the robot hand of the present invention can easily recognize the grasping state of an object while using jamming dislocation.

1, 2, 3, 4, 5, 6, 7 Robot hand 10 Base plate 11 Vacuum suction port 12 Bag internal suction port 20 Bag body 21 Bag body 22 Holding plate 23 Small bag body 30 Powder 31 Insulating powder 40 Detecting parts 41, 42 Electrodes 43 Insulating film 43a Through hole 50 Detecting part 51 Dielectric film 52 First electrode 53 Second electrode 60 Detecting part 61 Electromagnetic induction type proximity sensor 70 Base plate 71 Through hole 80 Bag 81 Bag main body 82 Holder Plate 83 Partition wall 90 Chamber X, Y Target object Z Test piece Z1 Base plate Z2 Square column

Claims (7)

A robot hand capable of gripping an object by adsorbing it to a bag body by jamming transfer ,
base plate and
a deformable bag body having an opening attached to one side of the base plate;
Powder that has conductivity and is filled inside the bag;
a detection unit that grasps the grasping state of the object by electrically or magnetically detecting the uneven distribution of the powder;
and a suction device that reduces the pressure inside the bag ,
A robot hand in which a filling rate of the powder into the bag is 70% by volume or more and less than 85% by volume . The detection unit has a plurality of electrodes provided spaced apart inside the bag, and uses a resistance value between a plurality of pairs of electrodes selected from the plurality of electrodes to detect uneven distribution of the powder. The robot hand according to claim 1. The detection unit includes a plurality of bag-shaped dielectric films provided inside the bag, a first electrode provided inside each of the plurality of dielectric films, and an outside of the dielectric film provided with the first electrode. and a second electrode provided inside the bag, and a capacitance value between the first electrode and the second electrode is used to detect uneven distribution of the powder. Robot hand described in. The detection unit includes a plurality of electromagnetic induction proximity sensors fixed to the base plate at a distance, and changes in impedance of a detection coil of the plurality of electromagnetic induction proximity sensors is used to detect uneven distribution of the powder. The robot hand according to claim 1, which uses: A chamber covering the other side of the base plate and capable of storing the powder therein,
The bag has a partition wall that divides the inside of the bag into a plurality of small chambers into which the powder cannot move,
The above-mentioned small room is in contact with the above-mentioned base board,
The base plate communicates each small room with the inside of the chamber and has a through hole through which the powder can pass,
The robot hand according to any one of claims 1 to 4, wherein the powder can freely move between the small rooms via the chamber. Further comprising insulating powder filled inside the bag,
The content of the powder based on the total of the conductive powder and the insulating powder is 20% by mass or more and 45% by mass or less, according to any one of claims 1 to 5. robot hand. The bag body has a plurality of small bag bodies inside thereof,
The robot hand according to any one of claims 1 to 6, wherein the inside of each pouch body is filled with the powder.

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