JP2021122925A - Robot hand - Google Patents

Abstract

To provide a robot hand which improves maintainability.SOLUTION: In a finger body section 14 of a finger section 13, a storage recess 19 recessed from an outer surface 18 to an inner surface 17 side and a communication section 35 which communicates the inner surface with the storage recess are formed. A sensor 52 which is provided in a portion to which external force is applied from an article in the finger section 13 is used as a part of components of a sensor unit 51 and is coated with a sensor coating section 75 which is formed of a material softer than that of the sensor. The sensor unit is stored in the storage recess in a state in which a part of the sensor coating section is exposed from the inner surface through the communication section. The sensor unit is fastened to the finger body section with bolts 83 and 85 and nuts 84 and 86 in a direction from the outer surface to the inner surface. A cover 87 for closing the storage recess is fastened to the finger body section with bolts 92, 94, and 96 and nuts 93, 95, and 97 in a direction from the outer surface to the inner surface.SELECTED DRAWING: Figure 5

Description

The present invention relates to a robot hand that operates an article with a finger.

A robot hand including a finger portion for operating an article and a sensor provided at a position where an external force from the article acts on the finger portion is known. In this robot hand, the sensor detects an external force acting on the article, and the article is operated by the finger portion with a force according to the detection result. As an industrial robot hand having such a configuration, for example, there is one described in Patent Document 1.

Japanese Unexamined Patent Publication No. 2012-161876

The robot hand can be used with the sensor exposed in a room where air cleanliness is ensured in a factory or the like. However, in a robot hand used for a robot that is operated in front of a customer, such as a robot that serves customers and a robot that shows movements, it is necessary to cover and protect the sensor with a soft covering portion such as a soft cover. In addition, the robot hand is also required to have a design so that it can be seen by customers. In order to meet these demands, the structure of the robot hand becomes more complicated than that of the above-mentioned industrial robot hand. Along with this, there is a problem that maintainability is lowered when the sensor is replaced.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a robot hand capable of improving maintainability.

A robot hand that solves the above problems includes a finger portion for operating an article and a sensor provided at a position where an external force from the article acts on the finger portion, and the sensor exerts an external force acting on the article. A robot hand that detects and operates the article by the finger portion with a force according to the detection result, and the skeleton portion of the finger portion has a surface facing the article as an inner surface, and the article is It is composed of a finger body portion having a surface on the opposite side as an outer surface, and the finger body portion is formed with an accommodating recess recessed from the outer surface toward the inner surface side and a communicating portion communicating the inner surface and the accommodating recess. The sensor is used as a part of a component of the sensor unit, and is covered with a sensor covering portion formed of a material softer than the sensor while forming a part of the component, and the communication thereof. The sensor unit is housed in the housing recess in a state where a part of the sensor covering portion is exposed from the inner surface of the finger body portion through the portion, and the housing recess is closed by a cover. The sensor unit and the cover are fastened to the finger body by a fastener in a direction from the outer surface to the inner surface.

In the robot hand having the above configuration, the sensor unit is covered with a cover that closes the accommodating recess and is not exposed from the outer surface of the finger body portion. Further, in the robot hand, the sensor is covered by the sensor covering portion and is not exposed from the inner surface of the finger body portion. Therefore, the appearance of the finger portion is improved as compared with the case where the sensor unit is exposed from the outer surface of the finger body portion or the sensor is exposed from the inner surface of the finger body portion.

Further, the sensor covering portion regulates that dust and the like in the air come into contact with the sensor. The external force acting on the article when the finger portion operates the article is transmitted to the sensor via the sensor covering portion. Here, the sensor coating is made of a material that is softer than the sensor. Therefore, the influence of the sensor covering on the detection performance of the sensor is smaller than that in the case where the sensor covering is made of a material harder than the sensor.

Further, the sensor unit and the cover are attached to the finger body portion by fastening with the fastener in the direction from the outer surface to the inner surface of the finger body portion. Therefore, the mounting work becomes easier as compared with the case where the fastening by the fastener is performed from both the direction from the outer surface to the inner surface of the finger body portion and the direction from the inner surface to the outer surface.

Further, the fastening by the fastener is released in the direction opposite to the above, that is, the fastening is released in the direction from the inner surface to the outer surface of the finger body portion, so that the sensor unit and the cover are released from the finger body portion. Each is removed. The removal work becomes easier as compared with the case where the fastening is released in both the direction from the inner surface to the outer surface of the finger body portion and the direction from the outer surface to the inner surface.

In the robot hand, an inner fastener and an outer fastener are used as the fastener, the sensor unit is fastened to the finger body portion by the inner fastener, and the cover is fastened to the finger body portion by the inner fastener. It is preferable that the sensor unit is fastened to the finger main body by the outer fastener at a place different from the fastening point to the finger main body.

According to the above configuration, the sensor unit housed in the housing recess is fastened to the finger body portion by the inner fastener. Further, the cover is fastened to the finger main body by the outer fastener at a place different from the fastening point to the finger main body of the sensor unit by the inner fastener. In this way, the sensor unit and the cover are separately fastened to the finger body. Therefore, it becomes easier to attach the sensor unit to the finger body with high accuracy as compared with the case where the sensor unit and the cover are fastened to the finger body with a common fastener.

In the robot hand, the finger body is movably attached to the hand body at its base end, and a touch pen is attached to the tip of the finger body to ground the touch pen. It is preferable that the wire is drawn out of the base end portion and connected to the hand main body portion via the accommodating recess of the finger main body portion and the sensor unit.

As described above, the ground wire of the touch pen is pulled out of the base end portion of the finger body portion and connected to the hand body portion via the accommodating recess of the finger body portion and the sensor unit. As a result, the appearance is improved as compared with the case where the ground wire is arranged outside the finger body.

In the robot hand, a sensor-side connector is connected to the sensor, and a main body-side connector to which the sensor-side connector is connected is fixed to the accommodating recess from the same direction as the fastening direction by the fastener. Is preferable.

According to the above configuration, the sensor-side connector is coupled to the main body-side connector by being moved in the same direction as the fastening direction by the fastener. Therefore, as compared with the case where the sensor side connector is moved in a direction different from the above to perform the coupling, the work of connecting or disconnecting the sensor side connector to the main body side connector becomes easier.

According to the robot hand, maintainability can be improved.

The partial perspective view which shows the schematic structure of the robot hand in one Embodiment. A partial perspective view of the finger portion in FIG. 1 as viewed from the outer surface side. A partial perspective view of the finger portion in FIG. 1 as viewed from the inner surface side. A partial cross-sectional view showing a mounting portion of a sensor covering portion and a peripheral portion thereof in one embodiment. The exploded perspective view which shows the component of the finger part of FIG. The schematic diagram of the sensor in one Embodiment. It is a figure explaining the internal structure of the finger part in one Embodiment, and is the partial perspective view which shows the state which the sensor attachment part is arranged with respect to the finger body part, and the touch pen and the earth wire are arranged. A partial perspective view showing a positional relationship between a sensor mounting portion and a ground wire in one embodiment. The perspective view of the sensor covering part in one Embodiment. The perspective view which shows the state before the sensor side connector in one Embodiment is connected to the main body side connector. The perspective view which shows the state which the sensor side connector in one Embodiment is connected to the main body side connector.

Hereinafter, one embodiment of the robot hand will be described with reference to the drawings.
As shown in FIG. 1, the robot hand 10 includes a hand main body 12 connected to the arm 11 and a pair of finger portions 13 attached to the hand main body 12. Each finger portion 13 is for operating and gripping the article A in the present embodiment. The skeleton portion of each finger portion 13 is composed of a finger body portion 14 extending from the hand body portion 12 in a state parallel to each other. Here, the side of each finger portion 13 of the finger body portion 14 near the hand body portion 12 is referred to as the base end, the base end side, etc., and the side far from the hand body portion 12 is referred to as the tip end, the tip end side, or the like. This point is the same for the other constituent members of the finger portion 13.

The finger body portion 14 for each finger portion 13 has a surface facing the article A as an inner surface 17 when gripping the article A, and has a surface opposite to the article A as an outer surface 18.
When it is necessary to specify the direction in the explanation of each part of the finger body portion 14, the direction in which the inner surface 17 and the outer surface 18 are lined up is referred to as the thickness direction, and the direction from the base end to the tip end or vice versa. The direction from to the base end is called the length direction. Further, the direction orthogonal to both the thickness direction and the length direction (vertical direction in FIG. 1) is defined as the width direction. These matters are the same for other members constituting the finger portion 13.

As shown in FIGS. 1 and 3, the finger body portion 14 for each finger portion 13 is attached to the hand body portion 12 by a bolt 16 inserted through its own base end portion 15. In the finger body portion 14 for each finger portion 13, the dimension in the length direction is set longer than the dimension in the width direction and the dimension in the thickness direction in the portion other than the base end portion 15.

The hand body 12 includes a drive unit such as an electric motor that drives each finger unit 13 to move both finger units 13 in a direction of approaching or separating from each other in a parallel state, and a control unit that controls the drive unit ( Both are built-in (not shown). The two finger portions 13 can grip the article A by approaching each other and release the article A by separating from each other.

As shown in FIG. 5, the finger body portion 14 is formed with a storage recess 19 that is open on the outer surface 18 and is recessed toward the inner surface 17, and is recessed from above to downward in FIG. A step portion 22 is formed around the accommodating recess 19 of the finger body portion 14 so as to be slightly recessed toward the inner surface 17 side of the outer surface 18 of the finger body portion 14.

A partition wall portion 23 having a notch portion 24 is formed in the accommodating recess 19 at a position slightly distant from the tip end surface of the finger body portion 14 toward the proximal end side.
As shown in FIGS. 3 and 5, a pair of bolt insertion holes 25 and 26 have the same widths as those of the inner bottom portion 21 of the accommodating recess 19 at a position slightly distant from the partition wall portion 23 toward the base end side. It is formed in a state of being separated in the direction. One bolt insertion hole 25 is connected to a nut accommodating portion 34 that opens on the inner surface 17 of the finger body portion 14. The other bolt insertion hole 26 is connected to the nut accommodating portion 33 that opens on the inner surface 17.

As shown in FIG. 5, a communication portion for communicating the accommodating recess 19 and the inner surface 17 in the inner bottom portion 21 of the accommodating recess 19 at a position slightly distant from the bolt insertion holes 25 and 26 toward the base end side. 35 is formed. The portion where the communication portion 35 is formed is a portion where the finger portion 13 comes into contact with the article A and an external force from the article A acts when the article A is operated. The communication portion 35 is formed of an oval hole elongated in the length direction rather than the width direction. In the inner bottom portion 21, an annular step portion 36 that is slightly recessed toward the inner surface 17 side from the inner bottom surface of the inner bottom portion 21 is formed around the communication portion 35.

The inner bottom portion 21, which is slightly separated from the communication portion 35 and the step portion 36 toward the base end side, in other words, the pair of bolt insertion holes 25, 26 sandwiching the communication portion 35 and the step portion 36. A pair of bolt insertion holes 37 and 38 are formed in a portion opposite to the above side in a state where the bolt insertion holes 37 and 38 are separated from each other in the width direction. As shown in FIGS. 3 and 5, one bolt insertion hole 37 is connected to a nut accommodating portion 42 that opens on the inner surface 17 of the finger body portion 14. The other bolt insertion hole 38 is connected to the nut accommodating portion 41 that opens on the inner surface 17.

At the inner bottom portion 21, where the two bolt insertion holes 37 and 38 are separated from each other by a certain distance toward the proximal end side, the cable support portion 43 and one bolt insertion hole 45 are provided in the width direction of each other. It is formed in a separated state. The bolt insertion hole 45 is connected to a nut accommodating portion 46 that opens on the inner surface 17.

In the inner bottom portion 21, the main body side connector 47 shown in FIGS. 10 and 11 is fixed in the region between the bolt insertion holes 37 and 38 and the cable support portion 43 and the bolt insertion hole 45. Note that in FIGS. 5 and 7, the main body side connector 47 is not shown. As shown in FIGS. 10 and 11, the main body side connector 47 is connected to a cable (not shown) extending from the hand main body 12 (see FIG. 1). The main body side connector 47 protrudes from the inner bottom portion 21 of the accommodating recess 19 toward the outer surface 18 side in the thickness direction, and has an adhered portion 48 to which the insertion / detachment portion 62 of the sensor side connector 61 described later is connected. doing.

As shown in FIG. 5, each finger portion 13 has a sensor unit 51 including a sensor 52, a sensor mounting portion 63, and a sensor covering portion 75 in addition to the finger body portion 14.
The sensor 52 is composed of a dielectric elastomer actuator that expands and contracts in the thickness direction. As shown in FIG. 6, the sensor 52 includes a plurality of sheet-shaped dielectric layers 53 made of dielectric elastomer, and positive electrode 54 and negative electrode 55 as electrode layers arranged on both sides of the dielectric layer 53 in the thickness direction. , It is composed of a laminated multilayer structure. An insulating layer 56 is laminated on the outermost layer of the sensor 52.

When a DC voltage is applied between the positive electrode 54 and the negative electrode 55, the sensor 52 compresses the dielectric layer 53 in the thickness direction and presses the surface of the dielectric layer 53 according to the magnitude of the applied voltage. It deforms so as to extend in the direction along it. The sensor 52 is arranged so that the stacking direction of each of the layers constituting the sensor 52 coincides with the thickness direction of the finger body portion 14.

The dielectric elastomer constituting the dielectric layer 53 is not particularly limited, and a dielectric elastomer used in a known dielectric elastomer actuator can be used. Examples of the dielectric elastomer include crosslinked polyrotaxane, silicone elastomer, acrylic elastomer, and urethane elastomer. One of these dielectric elastomers may be used, or a plurality of types may be used in combination.

Examples of the material constituting the positive electrode 54 and the negative electrode 55 include a conductive elastomer, carbon nanotubes, Ketjen Black (registered trademark), and a metal vapor deposition film. Examples of the conductive elastomer include a conductive elastomer containing an insulating polymer and a conductive filler.

Examples of the insulating polymer include crosslinked polyrotaxane, silicone elastomer, acrylic elastomer, and urethane elastomer. One of these insulating polymers may be used, or a plurality of types may be used in combination. Examples of the conductive filler include Ketjen Black (registered trademark), carbon black, metal particles such as copper and silver, and the like. One of these conductive fillers may be used, or a plurality of types may be used in combination.

The insulating elastomer constituting the insulating layer 56 is not particularly limited, and a known insulating elastomer used for the insulating portion of the known dielectric elastomer actuator can be used. Examples of the insulating elastomer include crosslinked polyrotaxane, silicone elastomer, acrylic elastomer, and urethane elastomer. One of these insulating elastomers may be used, or a plurality of types may be used in combination.

The capacitance of the sensor 52 made of a dielectric elastomer actuator is a parameter that is inversely proportional to the distance between the electrodes and proportional to the area (opposing area) of the electrodes, and changes according to the shape of the sensor 52. Therefore, when a voltage is applied to the sensor 52 and the sensor 52 is compressed in the thickness direction of the dielectric layer 53, the capacitance of the sensor 52 also increases. A correlation is established between the voltage applied to the sensor 52 and the capacitance, which increases as one increases.

Similarly, when an external force acts on the sensor 52 and the sensor 52 is compressed in the thickness direction of the dielectric layer 53, the capacitance of the sensor 52 increases. Therefore, even if the applied voltage to the sensor 52 is the same, the capacitance of the sensor 52 in the state where the external force is not acting on the sensor 52 and the sensor 52 in the state where the external force is acting on the sensor 52. There is a difference with the capacitance of.

As shown in FIG. 5, the positive electrode 54 is connected to the sensor-side connector 61 via a cable 57. The negative electrode 55 is connected to the sensor-side connector 61 via a cable 58.

As shown in FIGS. 5, 10 and 11, the sensor-side connector 61 has an insertion / removal portion 62, and the insertion / removal portion 62 covers the main body-side connector 47 from the outer surface 18 side in the thickness direction. It is coupled to the landing portion 48.

As shown in FIG. 5, the sensor 52 configured as described above is used as a part of the components of the sensor unit 51. In the sensor 52, the portion excluding the cables 57 and 58 and the sensor side connector 61 is on the side of the sensor unit 51 closer to the article A, more specifically, on the inner surface 17 side of the sensor mounting portion 63 in the thickness direction. Have been placed.

As shown in FIGS. 5 and 8, the sensor mounting portion 63 is used for mounting the sensor 52 in the accommodating recess 19 in a state of being positioned at a position corresponding to the communication portion 35. The sensor mounting portion 63 includes an insertion portion 64 in which at least a part thereof is inserted into the communication portion 35 and protrudes from the inner surface 17 of the finger body portion 14, and a mounting body portion 66 in which the entire sensor mounting portion 63 is arranged in the accommodating recess 19. It has.

A flange portion 65 is formed on the outer periphery of the boundary portion of the insertion portion 64 with the mounting main body portion 66. A mounting protrusion 67 having a bolt insertion hole 68 is formed at one end (left in FIG. 5) of the outer circumference of the mounting body 66 in the length direction, and the other (right in FIG. 5). ), A mounting protrusion 71 having a bolt insertion hole 72 is formed at the end of the). Both mounting protrusions 67 and 71 are located on opposite sides of each other with an intermediate portion of the mounting main body 66 in the width direction. In FIG. 5, the mounting protrusion 67 is formed on the right side portion of the intermediate portion of the mounting main body portion 66 in the width direction, and the mounting protrusion 71 is formed on the left side portion. Further, a cable retainer 73 is formed on the outer circumference of the mounting main body 66 and between the two mounting protrusions 67 and 71 so as to project from the mounting main body 66 to one side (left side in FIG. 5) in the width direction. There is. In the present embodiment, the cable retainers 73 are formed at two locations in the mounting main body 66 in the above-mentioned length direction, but they may be formed at one location or three or more locations.

As shown in FIGS. 5 and 9, the sensor covering portion 75 includes a covering main body portion 76 and a mounting portion 77, and is formed entirely of a material softer than the sensor 52, or a resin material in the present embodiment. .. The covering main body portion 76 has a low-height bottomed tubular shape in which the surface on the outer surface 18 side in the thickness direction is opened, and is inserted into the communication portion 35 to cover the sensor 52 and the insertion portion 64. do. The mounting portion 77 targets the peripheral edge portion on the outer surface 18 side of the covering main body portion 76, and is formed over the entire circumference of the peripheral edge portion.

As shown in FIGS. 4 and 5, the mounting portion 77 has a portion 78 having a U-shaped cross section at least in a part in the circumferential direction. The mounting portion 77 is fitted to the flange portion 65 of the sensor mounting portion 63 at this portion 78. By this fitting, the sensor covering portion 75 is attached to the sensor mounting portion 63. The portion of the mounting portion 77 on the inner surface 17 side in the thickness direction is formed over the entire circumference of the peripheral edge portion of the covering main body portion 76. As shown in FIGS. 4 and 9, a seal portion 79 made of ridges is integrally formed on the inner surface 17 side portion of the mounting portion 77 over the entire circumference thereof.

Then, as shown in FIG. 5, a part of the insertion portion 64 of the sensor mounting portion 63 in the sensor unit 51 and a part of the coating main body portion 76 of the sensor covering portion 75 are inserted into the communication portion 35. .. The flange portion 65 and the mounting body portion 66 of the sensor mounting portion 63 and the mounting portion 77 of the sensor covering portion 75 are housed in the housing recess 19.

Here, as shown in FIGS. 5 and 7, a partition wall portion 23 is formed at the tip end portion of the accommodating recess 19 as described above. In the accommodating recess 19, the region on the tip side of the partition wall portion 23 is the assembled portion 27. Then, the touch pen 81 is assembled to the assembled portion 27 with its tip portion exposed to the outside of the finger body portion 14. The ground wire 82 connected to the touch pen 81 is passed through the notch 24 in the partition wall 23. The ground wire 82 is passed between the pair of bolt insertion holes 25 and 26 in the finger body portion 14 at a position close to the partition wall portion 23. Further, the ground wire 82 is arranged so as to bypass the communication portion 35. More specifically, as shown in FIGS. 5, 7 and 8, a part of the ground wire 82 has a side wall portion 28 on one side (left side in FIGS. 5 and 7) of the communication portion 35 and the finger body portion 14. It is placed between. The portion of the ground wire 82 is arranged between the inner bottom portion 21 of the accommodating recess 19 in the finger body portion 14 and the cable retainer 73 in the sensor mounting portion 63. As shown in FIGS. 5 and 7, the portion of the ground wire 82 on the base end side of the communication portion 35 is supported by the cable support portion 43 in a state of being separated from the inner bottom portion 21 of the accommodating recess 19 toward the outer surface 18 side. Has been done. The ground wire 82 is pulled out from the base end portion 15 of the finger main body portion 14 and is connected to the hand main body portion 12 (see FIG. 1).

Then, as shown in FIGS. 1, 5 and 7, the bolt 83 is inserted into the bolt insertion hole 68 of one mounting protrusion 67 in the sensor mounting portion 63 and the bolt insertion hole 26 of the finger body portion 14. Then, it is screwed into the nut 84 housed in the nut housing portion 33. Further, the bolt 85 is inserted into the bolt insertion hole 72 of the other mounting protrusion 71 in the sensor mounting portion 63 and the bolt insertion hole 37 of the finger body portion 14, and the nut is further accommodated in the nut accommodating portion 42. It is screwed into 86. The sensor mounting portion 63 is fastened to the finger body portion 14 by these bolts 83, 85 and nuts 84, 86. As described above, the sensor unit 51 is provided with the inner fastener made of a combination of the bolt 83 and the nut 84 and the inner fastener made of the combination of the bolt 85 and the nut 86 with respect to the finger body portion 14 from the outer surface 18 to the inner surface 17 It is concluded in the direction toward. These inner fasteners form a part of the fasteners.

In the state where the sensor unit 51 is fastened to the finger body portion 14 as described above, the seal portion 79 of the sensor covering portion 75 is pressed against the step portion 36 of the finger body portion 14. As shown in FIGS. 4 and 5, a communication portion 35 is formed in the finger body portion 14, but the sensor unit 51 and the step portion 36 are sealed by the seal portion 79, and water, dust, etc. are removed. It is restricted from entering the accommodating recess 19 through the communication portion 35.

As shown in FIG. 5, each finger portion 13 further includes a cover 87 having an outer shape corresponding to the step portion 22. In the cover 87, a bolt insertion hole 88 is formed at a position corresponding to the bolt insertion hole 25 in the finger body portion 14. Further, a bolt insertion hole 89 is formed at a position corresponding to the bolt insertion hole 38 in the cover 87. Further, a bolt insertion hole 91 is formed in the cover 87 at a position corresponding to the bolt insertion hole 45. Then, the peripheral portion of the cover 87 is placed on the stepped portion 22, so that the accommodating recess 19 is closed by the cover 87.

Further, as shown in FIGS. 1, 2 and 5, the bolt 92 is inserted through the bolt insertion hole 88 of the cover 87 and the bolt insertion hole 25 of the finger body portion 14 and is housed in the nut accommodating portion 34. It is screwed into the nut 93. The bolt 94 is inserted through the bolt insertion hole 89 of the cover 87 and the bolt insertion hole 38 of the finger body portion 14, and is screwed into the nut 95 housed in the nut accommodating portion 41. The bolt 96 is inserted into the bolt insertion hole 91 of the cover 87 and the bolt insertion hole 45 of the finger body portion 14, and is screwed into the nut 97 housed in the nut accommodating portion 46.

The cover 87 is fastened to the finger body 14 by these bolts 92, 94, 96 and nuts 93, 95, 97. As described above, the cover 87 is composed of an outer fastener made of a combination of bolts 92 and nuts 93, an outer fastener made of a combination of bolts 94 and nuts 95, and an outer fastener made of a combination of bolts 96 and nuts 97. , It is fastened to the finger body portion 14 in the direction from the outer surface 18 to the inner surface 17. These outer fasteners form a part of the fasteners. The fastening is performed at a position different from the fastening location of the sensor unit 51 with respect to the finger body portion 14 by the inner fastener.

A sealing material (not shown) is provided between the peripheral edge portion of the cover 87 and the stepped portion 22 along the peripheral edge portion and the stepped portion 22 so as to surround the accommodating recess 19. This sealing material regulates water, dust, and the like from entering the accommodating recess 19 from the outside of the finger portion 13 through between the step portion 22 and the peripheral edge portion of the cover 87.

By the way, the control unit in the hand body unit 12 of FIG. 1 controls the applied voltage applied to the sensor 52 from a power source (not shown) such as a battery. When the voltage applied to the sensor 52 is changed in the control unit, the sensor 52 is deformed into a shape according to the magnitude of the applied voltage.

Further, the control unit measures the capacitance of the sensor 52 by applying an AC voltage sufficiently smaller than the applied voltage to the applied voltage. Then, the control unit sets the applied voltage to the sensor 52 based on the relationship between the applied voltage to the sensor 52 and the measured capacitance of the sensor 52 so that the external force acting on the sensor 52 approaches a predetermined target value. Control.

Next, the operation of the present embodiment configured as described above will be described. In addition, the effects caused by the action will also be described.
In the robot hand 10 of the present embodiment, bolts 83, 85, 92, 94, 96 and nuts 84, 86, 93, 95, 97 are used as fasteners. With these fasteners, fastening is performed in the direction from the outer surface 18 to the inner surface 17 of the finger body portion 14. The above fastening is performed by rotating the bolts 83, 85, 92, 94, 96 in the tightening direction with respect to the nuts 84, 86, 93, 95, 97. By the above fastening, the sensor unit 51 and the cover 87 are attached to the finger body 14, respectively. Therefore, the mounting work becomes easier as compared with the case where the finger body portion 14 is fastened from both the direction from the outer surface 18 to the inner surface 17 and the direction from the inner surface 17 to the outer surface 18.

Further, by releasing the fastening in the opposite direction to the above, that is, by releasing the fastening in the direction from the inner surface 17 to the outer surface 18 of the finger body portion 14, the sensor unit 51 and the cover are released from the finger body portion 14. 87 are removed respectively. The fastening is released by rotating the bolts 83, 85, 92, 94, 96 in the loosening direction with respect to the nuts 84, 86, 93, 95, 97. The rotation is performed until the bolts 83, 85, 92, 94, 96 are disengaged from the nuts 84, 86, 93, 95, 97. The removal work becomes easier as compared with the case where the fastening is released in both the directions from the inner surface 17 to the outer surface 18 of the finger body portion 14 and the direction from the outer surface 18 to the inner surface 17.

Further, in the robot hand 10 of the present embodiment, as shown in FIG. 10, the sensor-side connector 61 is coupled to the main body-side connector 47 by being moved in the same direction as the fastening direction. Further, the sensor unit 51 is removed from the main body side connector 47 by being moved in the same direction as the fastening release direction. Therefore, as compared with the case where the sensor side connector 61 is moved in a direction different from the above, for example, as compared with the case where the sensor side connector 61 is moved in the above length direction, the sensor side connector 61 is connected to or detached from the main body side connector 47. It becomes easier to do the work.

As described above, according to the robot hand 10 of the present embodiment, it is possible to improve maintainability when replacing the sensor unit 51 or its component parts or the like as compared with the conventional one.

Further, in the present embodiment, a combination of the bolt 83 and the nut 84 and a combination of the bolt 85 and the nut 86 are used as the inner fastener. Further, as the outer fastener, a combination of the bolt 92 and the nut 93, a combination of the bolt 94 and the nut 95, and a combination of the bolt 96 and the nut 97 are used. Then, the sensor unit 51 housed in the housing recess 19 is fastened to the finger body 14 by the inner fastener. Further, the cover 87 is fastened to the finger body 14 by the outer fastener. In this way, the sensor unit 51 and the cover 87 are separately fastened to the finger body 14. Therefore, as compared with the case where the sensor unit 51 and the cover 87 are fastened to the finger body portion 14 by a common fastener, the work of attaching the sensor unit 51 to the finger body portion 14 with high accuracy becomes easier.

Further, in the robot hand 10 of the present embodiment, the sensor unit 51 is covered with a cover 87 that closes the accommodating recess 19, and is not exposed from the outer surface 18 of the finger body portion 14. Further, in the robot hand 10 of the present embodiment, the sensor 52 is covered by the sensor covering portion 75 and is not exposed from the inner surface 17 of the finger body portion 14. Therefore, the appearance of the finger portion 13 is improved as compared with the case where the sensor unit 51 is exposed from the outer surface 18 of the finger body portion 14 or the sensor 52 is exposed from the inner surface 17 of the finger body portion 14.

Further, in the robot hand 10 of the present embodiment, the ground wire 82 of the touch pen 81 passes between the accommodating recess 19 of the finger body portion 14 and the sensor unit 51, and is connected to the base end portion 15 of the finger body portion 14. It is pulled out to the outside and connected to the hand body 12. Therefore, the ground wire 82 is not exposed to the outside of the finger portion 13. The appearance of the robot hand 10 is improved as compared with the case where the robot hand 10 is arranged outside the finger body portion 14.

Further, the sensor covering portion 75 regulates that dust or the like in the air touches the sensor 52. The external force acting on the article A when the finger portion 13 operates the article A is transmitted to the sensor 52 via the sensor covering portion 75. Here, the sensor covering portion 75 is made of a material softer than the sensor 52. Therefore, the influence of the sensor covering portion 75 on the detection performance of the sensor 52 is smaller than that in the case where the sensor covering portion 75 is made of a material harder than the sensor 52.

According to this embodiment, the following effects can be obtained in addition to the above.
In the present embodiment, the fastening of the mounting protrusion 67 to the finger body 14 and the fastening of the mounting protrusion 71 to the finger body 14 are opposite to each other with the intermediate portion of the communication portion 35 in the width direction interposed therebetween. It is done in the following places. In other words, the two fastenings are performed at locations facing each other with the center of the communication portion 35 in between. Therefore, the sensor mounting portion 63 can be efficiently and well-balanced to be fastened to the finger body portion 14 even though the number of fastening points is small.

In the present embodiment, as the sensor 52, the dielectric layer 53 and the electrode layer (positive electrode 54 and negative electrode 55) are laminated in the direction in which the external force from the article A acts, and the direction in which the external force from the article A acts. A dielectric elastomer actuator that expands and contracts is used.

Therefore, the sensor 52 provided on the finger portion 13 functions as an actuator for adjusting the force (grip force) generated between the finger portion 13 and the article A, and the force generated between the finger portion 13 and the article A. It also functions as a detector to detect. Therefore, it is not necessary to provide a detection unit such as a pressure sensitive element separately from the sensor 52. Compared with the case where the detection unit is provided separately, the detection unit itself, the wiring connected to the detection unit, and the like can be omitted, and the configuration of the robot hand 10 can be simplified.

-In the robot hand 10 of the present embodiment, the sensor 52 is provided at a portion of the finger portion 13 that comes into contact with the article A. The sensor 52 made of a dielectric elastomer actuator has elasticity. Therefore, due to this elasticity, the impact at the time of contact between the finger portion 13 and the article A can be alleviated. Further, by elastically deforming the surface shape of the sensor 52 along the surface shape of the article A, the contact area between the article A and the sensor 52 can be secured, and the contact state between the article A and the finger portion 13 can be stabilized. can.

-The robot hand 10 of the present embodiment includes two finger portions 13. Therefore, when the article A is gripped, the article A can be stably gripped by independently adjusting the gripping force at each of the two contact points with respect to the article A. For example, when the gripped article A vibrates, the gripping force is insufficient at one contact point and the gripping force becomes excessive at another contact point. Even in such a case, each contact point is in a state of being excessive. It is possible to adjust the gripping force to an appropriate level.

It should be noted that the above embodiment can also be implemented as a modified example in which this is modified as follows. The above embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.

-As the fastener, members different from the bolts 83, 85, 92, 94, 96 and the nuts 84, 86, 93, 95, 97 may be used.
-The number and position of the bolt insertion holes 25, 26, 37, 38, 45, 88, 89, 91 may be changed.

The sensor unit 51 (sensor mounting portion 63) and the cover 87 may be fastened to the finger body portion 14 by a common fastener.
For example, when the bolt insertion holes 25 and 26 are used to fasten the sensor unit 51 and the cover 87 to the finger body portion 14, the ground wire 82 is provided between the bolt insertion holes 25 and 26 as in the above embodiment. By passing the finger body portion 14, the physique of the finger body portion 14 in the width direction can be reduced. This is due to the following reasons. As described above, a sealing material (not shown) is interposed between the peripheral edge portion of the cover 87 and the step portion 22. If the ground wire 82 is placed at a location other than between the bolt insertion holes 25 and 26, the distance between the peripheral edge of the cover 87 and the stepped portion 22 increases at that location, but the bolts sandwich the ground wire 82. Bolts and nuts are not used for fastening at locations opposite to the insertion holes 25 and 26. Therefore, in order to secure the sealing property between the peripheral edge portion of the cover 87 and the stepped portion 22, the countermeasure is taken by widening the width of the sealing material. On the other hand, when the ground wire 82 is arranged between the bolt insertion holes 25 and 26, the ground wire 82 is fastened with bolts and nuts on both sides in the width direction. It is possible to secure the sealing property between the peripheral edge portion of the cover 87 and the stepped portion 22 without increasing the width of the sealing material. Therefore, as described above, it is possible to reduce the physique of the finger body portion 14 in the width direction.

-The number of finger portions 13 in the robot hand 10 may be 1, or may be 3 or more. However, when gripping the article A, it is preferable to include two or more finger portions 13, and it is more preferable to include three or more finger portions 13 from the viewpoint of gripping stability.

-The operation by the finger portion 13 may be an operation other than the operation of gripping the article A. For example, by alternately executing the control for strengthening the gripping force and the control for weakening the gripping force while holding the article A, the gripped article A can be gradually slid off by its own weight. Further, in the state where the article A is gripped, the control for strengthening the gripping force and the control for weakening the gripping force are alternately executed, and the timing is shifted between the plurality of finger portions 13 to shake (vibrate) the gripped article A. )be able to. It can also be applied to the operation of turning a sheet such as paper.

10 ... Robot hand 12 ... Hand main body 13 ... Finger 14 ... Finger main body 15 ... Base end 17 ... Inner surface 18 ... Outer surface 19 ... Containment recess 35 ... Communication part 47 ... Main body side connector 51 ... Sensor unit 52 ... Sensor 61 ... Sensor side connector 75 ... Sensor coating 81 ... Touch pen 82 ... Earth wire 83, 85 ... Bolt (consists of a part of each fastener and inner fastener)
84, 86 ... Nuts (constituting a part of each of the fasteners and the inner fasteners)
87 ... Cover 92, 94, 96 ... Bolt (consists of a part of each fastener and outer fastener)
93, 95, 97 ... Nuts (constituting parts of fasteners and outer fasteners)
A ... Goods

Claims (4)

A finger portion for operating the article and a sensor provided at a position where an external force from the article acts on the finger portion are provided, and the sensor detects an external force acting on the article and responds to the detection result. A robot hand that operates the article with the finger by force.
The skeleton portion of the finger portion is composed of a finger body portion having a surface facing the article as an inner surface and a surface opposite to the article as an outer surface.
The finger body portion is formed with a storage recess that is recessed from the outer surface toward the inner surface side, and a communication portion that communicates the inner surface and the storage recess.
The sensor is used as a part of a component of the sensor unit, forms a part of the component, and is covered with a sensor covering portion formed of a material softer than the sensor.
The sensor unit is housed in the housing recess in a state where a part of the sensor covering portion is exposed from the inner surface of the finger body portion via the communication portion.
The accommodating recess is closed by a cover.
A robot hand in which the sensor unit and the cover are fastened to the finger body by a fastener in a direction from the outer surface to the inner surface. As the fastener, an inner fastener and an outer fastener are used.
The sensor unit is fastened to the finger body by the inner fastener, and is fastened to the finger body.
The robot hand according to claim 1, wherein the cover is a place different from the place where the sensor unit is fastened to the finger body by the inner fastener, and is fastened to the finger body by the outer fastener. The finger body is movably attached to the hand body at its base end.
A touch pen is attached to the tip of the finger body.
The ground wire of the touch pen is drawn out to the outside of the base end portion via between the accommodating recess of the finger main body portion and the sensor unit, and is connected to the hand main body portion. Or the robot hand according to 2. Claims 1 to 3 in which a sensor-side connector is connected to the sensor, and a main body-side connector to which the sensor-side connector is connected is fixed to the accommodating recess from the same direction as the fastening direction by the fastener. The robot hand according to any one of the above.

Images