JP7152005B2 - Grasping device and robot arm - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (1) Announced at the exhibition hall of "2nd ROBODEX" from January 17 to 19, 2018 (2) June 2, 2018, " Presented on the DVD of the Robotics and Mechatronics Lecture 2018 (3) Announced on June 3, 2018 as a poster at the Robotics and Mechatronics Lecture 2018

The present invention relates to a grasping device for grasping an object to be grasped and a robot arm provided with the same.

Some conventional gripping devices, which are used as an end effector of a robot arm, for example, drive one end side of two rod-shaped members arranged opposite to each other, and grip an object to be gripped between the two rod-shaped members. Grippers are known that

Further, Patent Document 1 discloses a closed wrench capable of expanding and contracting an opening into which a bolt and a nut are fitted. In this box wrench, six slide bodies (movable members) annularly arranged so as to be adjacent to each other move by relatively moving slide surfaces (adjacent surfaces) between adjacent slide bodies. As a result, a regular hexagonal expansion/contraction opening (opening of the gripping space) formed by being surrounded by the sliding surfaces of the six slide bodies can be expanded/contracted to match the size of the bolt or nut.

In a gripping device such as the gripper described above, for example, when a large number of linear objects (wires, etc.) or rod-shaped objects are gripped objects, the other ends of the two rod-shaped members are closed while the two rod-shaped members are closed. The object to be grasped is pushed out from (the free end side), and the object to be grasped cannot be properly grasped. Further, in a gripping device such as the gripper described above, the position of the gripped object varies depending on the position on the gripper at which the gripped object is gripped.

The inventors of the present invention have found that these problems can be solved by a gripping device that utilizes a mechanism for expanding and contracting the expansion and contraction opening of the closed wrench disclosed in Patent Document 1. That is, in a state in which a large number of objects such as linear objects are placed in the gripping space within the expansion/reduction opening, the gripping space is contracted and the objects to be gripped are gripped in the gripping space. There is no place for the grasped object to escape, and it is possible to appropriately grasp even a large number of linear objects to be grasped. In addition, since the object to be grasped in the shrinking grasping space is brought closer to the center position of the grasping space and finally grasped, the center position of the object to be grasped is always aligned with the center position of the grasping space. The gripping position is highly accurate.

However, as a result of research by the present inventors, it has been found that such a grasping device has the following problems.
That is, in such a gripping device, gripped objects (not limited to gripped objects such as a large number of linear objects) are moved in the axial direction of the gripping space (direction perpendicular to the opening surface of the gripping space). When moving along, an external force in that direction (the axial direction of the gripping space) is applied to the movable member such as the slide body that forms the gripping space. When such an external force is applied, there is a possibility that the movable member may be displaced in the relevant direction or its posture may be changed. As a result, appropriate relative movement between the adjacent surfaces between the movable members is not possible, which hinders expansion/contraction of the gripping space and makes it difficult to properly grip the object.

In a gripping device such as the box wrench disclosed in Patent Document 1, which tightens or loosens a bolt or nut (object to be gripped) gripped in the gripping space, the direction perpendicular to the opening of the gripping space (the It is not used for moving the object to be grasped along the axial direction). Therefore, the problems described above cannot be imagined from such a gripping device.

In order to solve the above-described problems, the present invention moves a plurality of movable members annularly arranged so as to be adjacent to each other so that the adjacent surfaces of the adjacent movable members face each other to move the plurality of movable members. A gripping device in which a gripping space formed by being surrounded by movable members is reduced, and an object to be gripped is gripped in the gripping space, wherein the gripping space is located between two adjacent surfaces facing each other between adjacent movable members. The first engaging shape portion formed on the first adjacent surface that becomes the wall surface is opposed to the second engaging shape portion formed on the second adjacent surface that does not become the wall surface of the gripping space among the two adjacent surfaces. , engaging such that relative displacement in one or both directions along a direction perpendicular to the direction of relative movement of the two adjacent surfaces and parallel to the adjacent surfaces is restricted; It is characterized.
In this gripping device, the two adjacent surfaces facing each other between the adjacent movable members are engaged with each other by the first engaging shape portion and the second engaging shape portion formed respectively. While the relative displacement in the direction perpendicular to the relative movement direction in which the adjacent surfaces relatively move and parallel to the adjacent surfaces (hereinafter referred to as "relative movement orthogonal direction") is regulated, the relative movement You can move relative to the direction. Accordingly, when an object to be grasped is grasped in a grasping space formed by being surrounded by the plurality of movable members and the object to be grasped is moved along the axial direction of the grasping space (perpendicular direction of relative movement), the movable members On the other hand, even if a load (external force in the direction perpendicular to the relative movement) is applied, the movable member is less likely to shift in the direction perpendicular to the relative movement or change its posture. Therefore, even when the object to be grasped is moved along the axial direction of the grasping space (perpendicular direction of relative movement), appropriate relative movement between the adjacent surfaces can be ensured, and expansion/contraction of the grasping space (movement of the movable member) is not hindered. It is possible to suppress the occurrence of a serious situation.
Moreover, the edge portion of the shape of the first engaging shape portion formed on the first adjacent surface, which is the wall surface of the gripping space, may be caught by the object to be gripped. can serve as a non-slip function for the object to be grasped. Therefore, when the object to be grasped is moved along the axial direction (perpendicular direction of relative movement) of the grasping space, the object to be grasped can be grasped without slipping in the grasping space.

Further, according to the present invention, in the gripping device, the first engaging shape portion is also restricted from being displaced relative to the second engaging shape portion in a direction in which the two adjacent surfaces are separated from each other. It is characterized by engaging in such a way that
If the manufacturing error or assembly error of the movable member is large, the two adjacent surfaces that relatively move between the adjacent movable members may separate or incline during the movement of the movable member. The surfaces may not be able to move relative to each other appropriately, and the expansion/contraction operation of the grasping space may not be performed appropriately.
According to this gripping device, the first engaging shape portion and the second engaging shape portion are engaged so as to restrict the relative displacement in the direction in which the two adjacent surfaces are separated from each other, Separation or inclination of the two adjacent surfaces from each other is restricted during movement of the movable member. Therefore, even if the manufacturing error or the assembly error of the movable member or the like is somewhat large, it is possible to stably ensure the relative movement of the two adjacent surfaces, and to maintain the appropriate expansion/contraction operation of the gripping space.

Further, according to the present invention, in the gripping device, the first engagement shape portion has a groove shape extending in the relative movement direction, and the second engagement shape portion has a convex shape that engages with the groove shape. It is characterized by
When the first engaging shape portion formed on the first adjacent surface, which is the wall surface of the gripping space, of the two adjacent surfaces facing each other includes a convex shape, when the gripping space is reduced, Convex shapes on one adjacent surface may interfere with each other, making it impossible to reduce the gripping space any further.
In this gripping device, the first engagement shape portion formed on the first adjacent surface that forms the wall surface of the gripping space is formed in a groove shape, and the second engagement shape portion that is formed on the second adjacent surface that does not form the wall surface of the gripping space. The mating shape portion has a convex shape that engages with the groove shape. According to this, even if the gripping space is reduced, the above-described interference does not occur, so the gripping space can be reduced to a smaller size, and the gripping space can be completely closed. It is possible to grasp a graspable object of any size.

Further, according to the present invention, in the gripping device, the first adjacent surface is a high-friction surface that increases the frictional force in a direction perpendicular to the direction of relative movement and parallel to the adjacent surface. It is characterized by
In this gripping device, the first adjacent surface that comes into contact with the object to be gripped is a high-friction surface, so that the anti-slip effect of the object to be gripped can be further enhanced. Therefore, when the object to be grasped is moved along the axial direction of the grasping space, the object to be grasped can be grasped in the grasping space without slipping.
The high-friction surface may be, for example, a high-friction surface obtained by processing (grooving, roughening, etc.) the first adjacent surface. A high-friction surface may be formed by attaching a high-friction material having a high

Further, according to the present invention, when a plurality of movable members move, the outer ends of the plurality of movable members move in the radial direction and contact the inner wall surface of an object to be grasped, thereby gripping the object to be grasped. The apparatus, wherein the plurality of movable members are annularly arranged adjacent to each other and are moved such that the adjacent surfaces of adjacent movable members face each other such that the outer ends of the plurality of movable members radiate. It is characterized by moving in a direction.
According to the present invention, since the outer ends of the plurality of movable members move in the radial direction by moving the adjacent surfaces of the adjacent movable members facing each other, the plurality of movable members can be driven by a single drive source. The outer end of each movable member can be moved radially while the members are interlocked.

Further, according to the present invention, in the gripping device, the first engagement shape portion formed on one of the two adjacent surfaces facing each other between the adjacent movable members is One direction or both along a direction perpendicular to the direction of relative movement of the two adjacent surfaces and parallel to the adjacent surfaces with respect to the second engaging shape formed on the other adjacent surface of It is characterized by engaging so that the relative displacement of the direction is restricted.
In this gripping device, the two adjacent surfaces facing each other between the adjacent movable members are engaged with each other by the first engaging shape portion and the second engaging shape portion respectively formed thereon, so that relative movement orthogonal to each other is achieved. While the relative displacement in the direction is regulated, it is possible to relatively move in the relative movement direction. As a result, when the object to be grasped is grasped by the outer ends of the plurality of movable members and the object to be grasped is moved along the direction perpendicular to the relative movement, a load (external force in the direction perpendicular to the relative movement) is applied to the movable members. Even if it is applied, the movable member is less likely to shift its position in the direction perpendicular to the relative movement or change its posture. Therefore, even when the object to be grasped is moved along the direction perpendicular to the relative movement, it is possible to ensure appropriate relative movement between the adjacent surfaces, and to avoid a situation in which the movement of the outer end portion of the movable member is hindered. can.

Further, according to the present invention, in the gripping device, the plurality of movable members are plate-shaped members, and face one flat plate surface of the plurality of movable members to regulate the moving direction of the plurality of movable members. and a moving force transmission member that faces the other flat plate surface of the flat plate member and transmits the moving force in the moving direction to the plurality of movable members. be.
According to this, the configuration of the plurality of movable members described above can be realized with a relatively simple configuration.

Further, in the gripping device of the present invention, the moving force transmission member may be moved by driving means for applying a driving force to move the moving force transmission member, and the plurality of movable members may move in conjunction with the movement of the moving force transmission member. It is characterized in that a directional moving force is transmitted.
According to this, it becomes possible to move the movable member by controlling the driving means.

Moreover, the present invention is characterized in that the gripping device further comprises torque control means for controlling the driving of the driving means based on the output torque of the driving means.
According to this, a desired gripping force can be stably obtained.

Further, according to the present invention, the gripping device is characterized by further comprising an information acquisition unit installed on the movable member for acquiring information on the movable member or the gripped object.
According to this, it is possible to realize control and processing using the information of the movable member and the object to be grasped acquired by the information acquiring means.

Further, according to the present invention, in the gripping device, the information acquisition means is contact pressure detection means for detecting a contact pressure with the object to be grasped, and based on the detection result of the contact pressure detection means. It is characterized by having contact pressure control means for controlling driving of the driving means.
According to this, a desired gripping force can be stably obtained.

Further, the present invention is a robot arm having a gripping device for gripping an object to be gripped, wherein the gripping device is used as the gripping device.
According to this robot arm, even when the object to be grasped is moved along the direction orthogonal to the relative movement of the grasping device, it is possible to ensure appropriate relative movement between the adjacent surfaces, thereby preventing the movement of the movable member from being hindered. can be suppressed.

According to the present invention, even when the object to be grasped is moved along the axial direction of the grasping space in the grasping device, it is possible to suppress the occurrence of a situation that hinders expansion and contraction of the grasping space, and the object to be grasped is grasped in the grasping space. Since it can be gripped without slipping, an appropriate grip can be achieved.

1 is an explanatory diagram showing an outline of a component assembly system according to Embodiment 1; FIG. FIG. 2 is an external perspective view of a robot arm in the parts assembly system as viewed obliquely from above; FIG. 4 is a perspective view showing the main configuration of an iris gripper used as an end effector of the robot arm; FIG. 4 is a perspective view of one of the six movable blades that constitute the iris gripper, viewed from the side facing the fixed disk; The top view which shows the movable disk which comprises the same iris gripper. The top view which shows the fixed disk which comprises the same iris gripper. (a) is a plan view showing a state in which a grasping space formed by being surrounded by six movable blades is expanded (open state). (b) is a plan view showing a state in which the gripping space is reduced (closed state); FIG. 4 is an explanatory diagram showing the moving direction of one of the six movable blades; FIG. 4 is a plan view showing another example of a movable disk that constitutes the iris gripper; FIG. 2 is a block diagram related to opening/closing control of the iris gripper; 5 is a cross-sectional view showing an engagement shape portion formed on the adjacent surface of the movable blade according to Configuration Example 1. FIG. FIG. 11 is a cross-sectional view showing an engagement shape portion formed on the adjacent surface of the movable blade according to Configuration Example 2; FIG. 11 is a cross-sectional view showing another example of the engaging shape portion in Configuration Example 2; FIG. 11 is a cross-sectional view showing an engagement shape portion formed on the adjacent surface of the movable blade according to Configuration Example 3; FIG. 11 is a cross-sectional view showing an engagement shape portion formed on the adjacent surface of the movable blade according to Configuration Example 4; FIG. 11 is a cross-sectional view showing an engagement shape portion formed on the adjacent surface of the movable blade according to Configuration Example 5; FIG. 12 is a cross-sectional view showing another example of the engagement shape portion in Configuration Example 5; FIG. 8 is a perspective view showing the main configuration of an iris gripper according to Embodiment 2; FIG. 4 is a plan view of the six movable blades that constitute the iris gripper, viewed from the side facing the movable disk. The top view which shows the movable disk which comprises the same iris gripper. The top view which shows the fixed disk which comprises the same iris gripper. The top view which shows the fixed ring which comprises the same iris gripper.

[Embodiment 1]
An embodiment in which a gripping device according to the present invention is applied as an end effector of a robot arm (hereinafter, this embodiment will be referred to as "Embodiment 1") will be described below.
In the first embodiment, in an assembly factory where parts are assembled, a robot arm is used to pick up a part from a transport case in which parts to be grasped are loaded, and the part is placed on a parts transport conveyor in the assembly line. placed in place. However, the grasping device according to the present invention, which is applied to such a robot arm, is merely an example, and may be applied to a robot arm used in other systems, or may be used as a grasping device other than a robot arm. It may be something that can be obtained.

FIG. 1 is an explanatory diagram showing an outline of a parts assembly system according to the first embodiment.
In the parts assembly system 1 of the first embodiment, the parts in the carrying case 50 placed at the parts picking position 2a are placed at predetermined positions on the parts assembly system conveyor 45 by the robot arm 10, and the parts are placed on the conveyor 45. The conveyed parts are used for assembly in the subsequent assembly process. The empty transport case 50 is moved to the case recovery position 2b.

FIG. 2 is an external perspective view of the robot arm 10 viewed obliquely from above.
The robot arm 10 has a base portion 11, an arm support portion 12, an arm portion 13, a hand portion 14, a hand portion 15, and the like. The base portion 11 is fixed to the frame by bolting.

The arm support part 12 is supported by the base part 11 so as to be rotatable by 360[°] in the direction indicated by the arrow A in the figure about the vertical axis passing through the center of the base part 11 . Further, the arm portion 13 has an upper arm portion 13a and a forearm portion 13b. The base end of the upper arm 13a is supported by the arm support 12 so as to be rotatable in the direction indicated by the arrow B in the drawing about a horizontally extending first shaft 13c. In addition, the base end of the forearm 13b is supported by the tip end of the upper arm 13a so as to be rotatable in the direction indicated by the arrow C in the drawing about the horizontally extending second shaft 13d. It is

The proximal end of the hand portion 14 is supported by the distal end of the forearm 13b so as to be rotatable in the direction indicated by the arrow D in the figure about the central axis 14a extending in the longitudinal direction of the forearm 13b. ing. Further, the hand portion 15 is supported by the distal end portion of the hand portion 14 so as to be rotatable in the direction indicated by the arrow E in the drawing about a horizontally extending third shaft 15a. Various types of end effectors can be attached to and detached from the hand portion 15, and in the first embodiment, an iris gripper, which will be described later, is attached.

FIG. 3 is a perspective view showing the main configuration of the iris gripper 20 used as the end effector of the robot arm 10. As shown in FIG.
FIG. 4 is a perspective view of one of the six movable blades 21A, 21B, 21C, 21D, 21E, and 21F that constitute the iris gripper 20, viewed from the side facing the fixed disk.
FIG. 5 is a plan view showing the movable disk 22 that constitutes the iris gripper 20. As shown in FIG.
FIG. 6 is a plan view showing the fixed disc 23 that constitutes the iris gripper 20. As shown in FIG.

The iris gripper 20 of the first embodiment includes six plate-shaped movable blades 21A, 21B, 21C, 21D, 21E, and 21F as a plurality of movable members annularly arranged so as to be adjacent to each other. The movable blades 21A to 21F of Embodiment 1 are all the same member, and the grasping space 30 formed by being surrounded by the six movable blades 21A to 21F has a regular hexagonal opening. In addition, it is also possible to combine movable members having different shapes.

The iris gripper 20 of Embodiment 1 has six movable blades 21A to 21F arranged in a ring on the same plane. It is different from the conventional iris mechanism (an iris mechanism applied to the aperture of a camera, etc.). In the iris gripper 20 of the first embodiment, the six movable blades 21A to 21F are arranged on the same plane while the adjacent surfaces (side surfaces of the movable blades) 21e and 21f between the adjacent movable blades are moved relative to each other. move within. Due to this movement, as shown in FIG. 7A, the gripping space 30 formed by being surrounded by the six movable blades 21A to 21F is expanded (opened), and as shown in FIG. can be switched to a state in which the gripping space 30 is reduced (closed state).

In the iris gripper 20 of Embodiment 1, the six movable blades 21A to 21F annularly arranged on the same plane as described above are sandwiched from both sides of the flat plate surface with the movable disk 22 as a moving force transmission member. A fixed disc 23 is arranged as a fixed member. The iris gripper 20 is attached to the end portion 15 via a fixed disc 23 .

As shown in FIG. 6, the fixed disc 23 is formed with long guide holes 23a to 23f as restricting portions for restricting the moving directions of the movable blades 21A to 21F. The guide protrusions 21a (see FIG. 4) of the movable blades 21A to 21F are inserted into these long guide holes 23a to 23f. As a result, when a moving force is applied to each of the movable blades 21A to 21F, each of the movable blades 21A to 21F is guided along each of the guide long holes 23a to 23f by the respective guide protrusions 21a, thereby moving in a predetermined moving direction. Move to

In Embodiment 1, the elongated guide holes 23a to 23f are linear, and the elongated guide projections 21a extend along the elongated guide holes 23a to 23f. The movable blades 21A to 21F moved by being guided by the guide holes 23a to 23f move in parallel in the longitudinal direction of the long guide holes 23a to 23f, respectively.

The movable disk 22 extends in the axial direction of the gripping space 30 (the direction perpendicular to the paper surface of FIG. 5), and around the rotation axis O passing through the center of the gripping space 30 (the disk center of the movable disk 22), It has a rotatable configuration. Specifically, a transmission gear member 24 is fixed on the outer disk surface of the movable disk 22 as shown in FIG. The transmission gear member 24 is fixed on the outer disk surface of the movable disk 22 by being screwed into the screw hole 22g of the movable disk 22 . The transmission gear member 24 has a gear 24a extending along the outer periphery of the movable disk 22. As shown in FIG.

As shown in FIG. 3, the gear 24a of the transmission gear member 24 is meshed with a motor gear 25 of a driving motor 26 as driving means which is screwed into a screw hole 23g of the fixed disc 23. As shown in FIG. The drive motor 26 is rotatable forward and backward. When the drive motor 26 is driven, the driving force is transmitted to the gear 24a of the transmission gear member 24 via the motor gear 25, causing the movable disk 22 to which the transmission gear member 24 is fixed to rotate about the rotation axis O. Gives the power to move. At this time, since the rotation restricting frame 27 fixed to the fixed disk 23 is arranged along the peripheral surface of the movable disk 22, the movable disk 22 rotates around the rotation axis O. 22 is guided by a rotation restricting frame 27 .

As shown in FIGS. 3 and 5, the movable disk 22 is formed with long transmission holes 22a-22f for transmitting the moving force to the respective movable blades 21A-21F. The transmitted projections 21b of the movable blades 21A to 21F are inserted into these long transmission holes 22a to 22f. As a result, when the movable disk 22 is rotated around the rotation axis O by the driving force of the drive motor 26, the movable blades 21A to 21F are pushed by the inner wall surfaces of the transmission slots 22a to 22f of the movable disk 22. A moving force is applied to the transmission projection 21b. As a result, each movable blade 21A to 21F is given a moving force in a predetermined moving direction, and each movable blade 21A to 21F moves in a predetermined moving direction.

In the first embodiment, one rotational input is used to move the six movable blades 21A to 21F, but two or more rotational inputs are used to move the six movable blades 21A to 21F. may

FIG. 8 is an explanatory diagram showing the moving direction of one movable blade 21A out of the six movable blades 21A to 21F. The moving directions of the other movable blades 21B to 21F are the same.
In FIG. 8, the direction in which the vertices of the movable blade 21A move at the center (rotational axis O) of the gripping space 30 when the gripping space 30 is closed as shown in FIG. It is illustrated as a direction. The X direction for the movable blade 21A is also illustrated in FIG. 7(a).

When the movable disk 22 rotates in the clockwise direction in FIG. 7 by the driving force of the drive motor 26, the movable blades 21A to 21F are guided along the guide slots 23a to 23f of the fixed disk 23 to move the movable blades 21A to 21F. The vertices of the blades 21A to 21F are translated toward the center of the gripping space 30 (rotational axis O). As a result, the gripping space 30 formed by being surrounded by the six movable blades 21A to 21F is reduced. When there is no gripped object (part) in the gripping space 30, the gripping space 30 is completely closed as shown in FIG. 7(b).

On the other hand, when the movable disk 22 rotates in the counterclockwise direction in FIG. 7 by the driving force of the drive motor 26, the apexes of the movable blades 21A to 21F move along the X direction to the center of the grasping space 30 (rotational axis O ), each of the movable blades 21A-21F translates. As a result, the gripping space 30 expands, and as shown in FIG. 7A, the gripping space 30 is opened.

As shown in FIG. 5, the movable disk 22 has an annular shape with an opening 22h at a portion facing the holding space 30. As shown in FIG. As a result, the object to be grasped does not interfere with the movable disk 22 when the object to be grasped is grasped in the grasping space 30 . Similarly, the fixed disc 23 is also ring-shaped with an opening 23h at a portion facing the gripping space 30, as shown in FIG. As a result, the object to be grasped does not interfere with the fixed disk 23 when the object to be grasped is grasped in the grasping space 30 .

When a part in the carrying case 50 is gripped by the robot arm 10, the iris gripper 20 with the gripping space 30 open as shown in FIG. The parts in the carrying case 50 are moved to a position where they can be gripped. As a result, the parts in the carrying case 50 enter the holding space 30 of the iris gripper 20 . In this state, the drive motor 26 is driven to rotate the movable disk 22 clockwise in FIG. The first adjacent surface 21e abuts and the component is gripped in the gripping space 30. As shown in FIG.

Here, a conventional gripper used in this type of robot arm has a configuration in which one end side of two rod-shaped members arranged opposite to each other is driven to grip an object to be gripped between the two rod-shaped members. There is In such a conventional gripper, the gripping position of the object to be gripped on the gripper varies, and the position of the gripped object to be gripped varies depending on the position on the gripper where the object to be gripped is gripped. end up As a result, when a conventional gripper is used in this parts assembly system, when placing a part picked up from the carrying case 50 on the parts transport conveyor 45, the part is placed at a position shifted from the target position on the parts transport conveyor 45 where the part should be placed. There is a risk that the part will be left behind and adversely affect the subsequent assembly process.

Also, if the objects to be gripped are a large number of linear objects (wires, etc.) or rod-shaped objects, the conventional gripper can grip the two rod-shaped members from the free end side while closing the two rod-shaped members. There is also a problem that the object to be grasped is pushed out and the object to be grasped cannot be properly grasped.

According to the iris gripper 20 according to the first embodiment, a part (object to be gripped) gripped in the shrinking gripping space 30 is gripped by coming into contact with the first adjacent surfaces 21e of the six movable blades 21A to 21F. The part is moved to the center (rotational axis O) of the space 30 and finally gripped with the center position of the part aligned with the center (rotational axis O) of the gripping space 30 . Therefore, there is no variation in the gripping position of the component on the iris gripper, and the accuracy of the gripping position is high. Therefore, when the parts picked up from the transport case 50 are placed on the parts transport conveyor 45, the parts can be placed at the target position on the parts transport conveyor 45 with high accuracy.

Further, according to the iris gripper 20 according to the first embodiment, even if the objects to be gripped are a large number of linear objects (such as wires) or rod-shaped objects, the six movable blades 21A to 21F The first adjacent surface 21e surrounds the side surfaces of the object to be grasped from all directions. Therefore, there is no way for the object to be grasped to escape, and even a large number of objects such as linear objects can be appropriately grasped.

However, in such an iris gripper 20, when the gripped object is moved along the axial direction of the gripping space 30 (the direction orthogonal to the opening surface of the gripping space) (for example, the object to be gripped is moved upward). When it is lifted or pushed into something), the six movable blades 21A to 21F forming the gripping space 30 are subjected to an external force in that direction. When such an external force is applied, the movable blades 21A to 21F may be displaced in the relevant direction (the axial direction of the gripping space 30), or the attitude of the movable blades 21A to 21F may change. As a result, the adjacent surfaces 21e and 21f between the adjacent movable blades cannot be properly moved relative to each other, which may hinder expansion/contraction of the gripping space 30. FIG.

Therefore, as shown in FIG. 4, each of the movable blades 21A to 21F in the iris gripper 20 of Embodiment 1 has a second adjacent surface among the two adjacent surfaces 21e and 21f facing each other between the adjacent movable blades. A convex shape 21d as a second shape engaging portion is formed on 21f, and a groove shape 21c as a first shape engaging portion is formed on the first adjacent surface 21e. The groove shape 21c of the first adjacent surface 21e extends in the flat plate surface direction of the movable blades 21A to 21F, that is, in the relative movement direction in which the two adjacent surfaces 21e and 21f move relative to each other. Each of the movable blades 21A to 21F engages with each other by engaging the convex shape 21d on the second adjacent surface 21f of the adjacent movable blade into the groove shape 21c formed on the first adjacent surface 21e of the movable blade 21A to 21F. are placed. As a result, the two adjacent surfaces 21e and 21f between the adjacent movable blades are restricted by the engagement between the convex shape 21d and the groove shape 21c in the relative displacement in the direction orthogonal to the relative movement direction. In this state, it is possible to relatively move in the direction of relative movement.

In the first embodiment, when a component is gripped in the gripping space 30 and lifted along the axial direction of the gripping space 30, a load (external force) in that direction is applied to the six movable blades 21A to 21F. . However, even if such an external force (external force perpendicular to the relative movement direction) is applied, the two adjacent surfaces 21e and 21f facing each other are engaged with the convex shape 21d and the groove shape 21c, and the relative movement in the direction perpendicular to the relative movement is prevented. Since the physical displacement is regulated, the movable blades 21A to 21F are less likely to be displaced in that direction or to change their postures. Therefore, even if a load (external force) is applied to the movable blades 21A to 21F in this direction when a part is grasped and lifted in the grasping space 30, the adjacent surfaces 21e and 21f between the movable blades can properly move relative to each other. Therefore, it is possible to avoid a situation that hinders expansion and contraction of the gripping space 30 .

Also, if the convex shape 21d is formed on the first adjacent surface 21e, which is the wall surface of the gripping space 30, of the two adjacent surfaces 21e and 21f facing each other, when the gripping space 30 is reduced, The convex shape 21d on the first adjacent surface 21e interferes, and the gripping space 30 cannot be reduced any further. Therefore, in the iris gripper 20 of Embodiment 1, the groove shape 21c is formed on the side of the first adjacent surface 21e, which is the wall surface of the gripping space 30, of the two adjacent surfaces 21e and 21f. According to this, even if the gripping space 30 is reduced, the above-mentioned interference does not occur, so that the gripping space 30 can be further reduced, and the gripping space 30 can be reduced as shown in FIG. Since it can be closed completely, it is possible to grip a smaller-sized object to be gripped.

Furthermore, in Embodiment 1, by forming the groove shape 21c on the first adjacent surface 21e, which is the wall surface of the gripping space, the object to be grasped is caught by the edges of the groove shape 21c. The frictional force in the axial direction of the gripping space 30 acting between it and the object to be gripped increases. In other words, the groove shape 21c can serve to prevent the gripped object from slipping. Therefore, when the object to be grasped is moved along the axial direction of the grasping space 30, the object to be grasped can be grasped without slipping.

In addition, the six movable blades 21A to 21F in Embodiment 1 have a basic shape of an equilateral triangle in which each vertex is 60°, and two vertexes related to a portion that does not contribute to the formation of the grasping space 30 are removed. , is configured to have a pentagonal shape as shown in FIG. As a result, the contact areas between the movable disk 22 and the fixed disk 23 and the movable blades 21A to 21F are reduced, so that the grasping space 30 can be expanded and contracted smoothly. In addition, as a result of the reduction in the portions of the movable blades 21A to 21F that protrude outward when the gripping space 30 is opened, the size of the iris gripper 20 can be reduced.

The configuration of the transmission slots 22a to 22f of the movable disk 22 and the configuration of the guide slots 23a to 23f of the fixed disk 23 in the first embodiment are not limited to those of the first embodiment. For example, regarding the configuration of the transmission slots 22a to 22f of the movable disk 22, for example, as shown in FIG. shape. However, regarding the configurations of the long transmission holes 22a to 22f of the movable disk 22 and the long guide holes 23a to 23f of the fixed disk 23, the movable blades 21A to 21F moving along the long guide holes 23a to 23f of the fixed disk 23 On the other hand, it is preferable to consider transmitting the moving force from the transmission elongated holes 22a to 22f of the movable disk 22 that rotates to the transmitted projections 21b of the movable blades 21A to 21F with as low a load as possible. In this respect, the configuration shown in FIG. 5 is preferable to the configuration shown in FIG.

Next, opening/closing control of the iris gripper 20 will be described.
FIG. 10 is a block diagram relating to the opening/closing control of the iris gripper 20. As shown in FIG.
A control device 31 drives and controls a driving motor 26 that imparts a moving force to the movable blades 21A to 21F to open and close the gripping space 30 . The control device 31 sends a drive signal to the drive motor 26 so as to open and close the gripping space 30 in accordance with a control command from the host controller. The drive motor 26 is driven in accordance with the drive signal to impart a moving force to the movable blades 21A-21F. As a result, the gripping space 30 performs an opening/closing operation according to the control command.

The control device 31 of the first embodiment functions as torque control means, adjusts the drive signal by receiving feedback of the output torque of the drive motor 26 , and grips an object (part) to be gripped within the gripping space 30 . Feedback control of force. This makes it possible to stably obtain a desired gripping force in accordance with the control command.

In the first embodiment, information acquisition means for detecting the contact pressure of the object (part) to be grasped is provided on the first adjacent surface 21e of each of the movable blades 21A to 21F that contacts the object (part) to be grasped. Pressure sensors 32A to 32F are provided as contact pressure detection means. Information on the contact pressure detected by the pressure sensors 32A to 32F is sent to the control device 31. FIG. The control device 31 of the first embodiment functions as contact pressure control means, adjusts the drive signal according to the contact pressure information from the pressure sensors 32A to 32F, ) is directly feedback-controlled. This makes it possible to stably obtain a desired gripping force in accordance with the control command.

In addition to the pressure sensors 32A to 32F, in the first embodiment, various information acquisition means for acquiring information on the movable blades 21A to 21F and objects to be grasped (parts) are installed on the movable blades 21A to 21F. may In the first embodiment, as an example of the information acquisition means, temperature sensors 33A to 33F are provided on the first adjacent surfaces 21e of the movable blades 21A to 21F contacting the objects (parts) to be grasped, as shown in FIG. ing. When the control device 31 of the first embodiment receives temperature information from the temperature sensors 33A to 33F, it transmits the information to the host controller. As a result, the host controller can grasp the temperature of the gripped object (component) gripped in the gripping space 30 .

Further, as another example of the information acquisition means, for example, an imaging sensor (imaging means) is installed on the upper surface or the lower surface of the movable blades 21A to 21F and picks up an image of the gripped object (component) gripped in the gripping space 30. mentioned. This makes it possible to perform object recognition of a grasped object (part) from a captured image.

Next, a configuration example of two adjacent surfaces 21e and 21f facing each other between adjacent movable blades will be described.

[Configuration example 1]
FIG. 11 is a cross-sectional view showing the engaging shape portions (the convex shape 21d and the groove shape 21c) formed on the adjacent surfaces 21e and 21f of the movable blades 21A to 21F according to Configuration Example 1. FIG.
As shown in FIG. 11, the convex shape 21d of this configuration example 1 is a rectangular parallelepiped convex portion extending in the normal direction from the second adjacent surface 21f, and continuously extending in the relative movement direction of the second adjacent surface 21f. Or it is formed intermittently. On the other hand, as shown in FIG. 11, the groove shape 21c of Configuration Example 1 is a rectangular parallelepiped concave portion extending in the normal direction from the first adjacent surface 21e, and is continuous over the relative movement direction of the second adjacent surface 21f. is formed in

In this configuration example 1, the convex shape 21d of the second adjacent surface 21f of one of the adjacent movable blades enters the groove shape 21c of the first adjacent surface 21e of the other movable blade, thereby forming the convex shape 21d and the groove shape 21c. engage each other. As a result, the relative displacement of the two adjacent surfaces 21e and 21f is regulated in any direction (both directions) along the direction perpendicular to the relative movement of the two adjacent surfaces 21e and 21f (vertical direction in the drawing). be done. Therefore, the object to be grasped is grasped in the grasping space 30 formed by being surrounded by the movable blades 21A to 21F, and the object to be grasped is moved in any direction along the axial direction of the grasping space 30 (perpendicular direction of relative movement). Even in such a case, the movable blades 21A to 21F are less likely to shift their positions in the direction orthogonal to the relative movement or to change their attitudes, and the occurrence of a situation that hinders expansion/contraction of the grasping space 30 is suppressed.

[Configuration example 2]
FIG. 12 is a cross-sectional view showing engagement shape portions (convex shape 21d and groove shape 21c) formed on adjacent surfaces 21e and 21f of movable blades 21A to 21F according to Configuration Example 2. As shown in FIG.
As shown in FIG. 12, the convex shape 21d of the second configuration example has a shape in which the tip of the base extending in the normal direction from the second adjacent surface 21f expands in the direction perpendicular to the relative movement (vertical direction in the drawing). and is formed continuously or intermittently over the relative movement direction of the second adjacent surface 21f. On the other hand, as shown in FIG. 12, the groove shape 21c of the configuration example 2 is a concave portion having a shape following the shape of the convex shape 21d, and is continuously formed over the relative movement direction of the second adjacent surface 21f. there is

In this configuration example 2, the convex shape 21d of the second adjacent surface 21f of one of the adjacent movable blades enters the groove shape 21c of the first adjacent surface 21e of the other movable blade, thereby forming the convex shape 21d and the groove shape 21c. engage each other. In this configuration example 2, as in configuration example 1 described above, the two adjacent surfaces 21e and 21f can be arranged in any direction (both directions) along the direction perpendicular to the relative movement of the two adjacent surfaces 21e and 21f (vertical direction in the figure). Relative displacement of the surfaces 21e and 21f is restricted. Therefore, the object to be grasped is grasped in the grasping space 30 formed by being surrounded by the movable blades 21A to 21F, and the object to be grasped is moved in any direction along the axial direction of the grasping space 30 (perpendicular direction of relative movement). Even in such a case, the movable blades 21A to 21F are less likely to shift in the direction perpendicular to the relative movement or to change their postures, and the occurrence of a situation that hinders expansion/contraction of the grasping space 30 is suppressed.

Further, in the configuration example 2, the convex shape 21d and the groove shape 21c are engaged with each other, so that the two adjacent surfaces 21e and 21f are separated from each other (the two adjacent surfaces are arranged in the horizontal direction in the drawing). (along and away) is also restricted. If the manufacturing or assembly errors of the movable blades 21A to 21F or the like are large, the two adjacent surfaces 21e and 21f may be separated from each other or inclined during movement of the movable blades 21A to 21F, and the two adjacent surfaces may be separated from each other. The faces may not be able to move appropriately relative to each other, and the holding space 30 may not be expanded or contracted appropriately. According to Configuration Example 2, the relative displacement of the two adjacent surfaces 21e and 21f in the direction separating them from each other is also restricted. It becomes difficult to separate or tilt. Therefore, even if the manufacturing error or assembly error of the movable blade or the like is somewhat large, the relative movement of the two adjacent surfaces 21e and 21f can be stably ensured, and the appropriate expansion/contraction operation of the gripping space 30 can be maintained. .

As shown in FIG. 13, a configuration may be adopted in which the contact area between the two is reduced by rounding the convex shape 21d and the groove shape 21c, thereby reducing the sliding resistance. Such a rounded configuration can be employed not only in the configuration example 2 but also in other configuration examples.

[Configuration example 3]
FIG. 14 is a cross-sectional view showing engagement shape portions (convex shape 21d and groove shape 21c) formed on adjacent surfaces 21e and 21f of movable blades 21A to 21F according to Configuration Example 3. As shown in FIG.
In this configuration example 3, the first adjacent surface 21e is designed to be a high-friction surface (a surface that can exert a higher friction force than the base material surface of the movable blades 21A to 21F) by increasing the frictional force in the direction perpendicular to the relative movement. It is configured. Specifically, a high-friction surface is formed by attaching a high-friction material 28 such as a rubber material that can exert a higher friction force than the base surface of the movable blades 21A to 21F. When an object to be grasped is gripped in the gripping space 30, the first adjacent surface 21e, which is a high-friction surface, contacts and grips the object to be gripped, so that the anti-slip effect of the object to be gripped can be enhanced.

Here, when the first adjacent surface 21e is a high-friction surface as in Configuration Example 3, when the first adjacent surface 21e contacts the second adjacent surface 21f, during the relative movement of these adjacent surfaces 21e and 21f, A high sliding load may prevent proper relative movement. Therefore, in configuration example 3, as shown in FIG. 14, a sufficient distance is provided between the first adjacent surface 21e and the second adjacent surface 21f, which are high-friction surfaces, so that the attitude of the movable blades 21A to 21F is slightly inclined. Also, the first adjacent surface 21e and the second adjacent surface 21f are configured so as not to come into contact with each other. Accordingly, even when the first adjacent surface 21e is a high-friction surface, appropriate relative movement between the adjacent surfaces can be ensured, and appropriate expansion/contraction operation of the gripping space 30 can be maintained.

The configuration of the convex shape 21d and the groove shape 21c of this configuration example 3 is the same as that of the configuration example 2 described above, but the configuration of the convex shape 21d and the groove shape 21c in another configuration example may be used.
Further, the high friction surface may be a high friction surface obtained by subjecting the first adjacent surface 21e to processing (grooving, roughening, etc.), for example.

[Configuration example 4]
FIG. 15 is a cross-sectional view showing engagement shape portions (convex shape 21d and groove shape 21c) formed on adjacent surfaces 21e and 21f of movable blades 21A to 21F according to Configuration Example 4. As shown in FIG.
In this configuration example 4, there are provided two engaging portions between the convex shape 21d and the groove shape 21c formed on the two adjacent surfaces 21e and 21f facing each other between the adjacent movable blades. With such a configuration, when an object to be grasped is grasped in the grasping space 30 and moved along the axial direction (perpendicular direction of relative movement) of the grasping space 30, the force in the direction applied to the movable blades 21A to 21F is increased. Relative displacement of the movable blades 21A to 21F in the direction perpendicular to the relative movement against the load (external force) can be more strongly restricted. Therefore, it is possible to ensure appropriate relative movement of the adjacent surfaces 21e and 21f between the movable blades even against a larger load (external force), and avoid a situation that hinders expansion and contraction of the gripping space 30. be able to.

The configuration of the convex shape 21d and the groove shape 21c of this configuration example 4 is the same as that of the configuration example 2 described above, but the configuration of the convex shape 21d and the groove shape 21c in another configuration example may be used.
Also, the number of engagement points may be three or more.

[Configuration example 5]
FIG. 16 is a cross-sectional view showing the engagement shape portions (hook shape) formed on the adjacent surfaces 21e and 21f of the movable blades 21A to 21F according to Configuration Example 5. As shown in FIG.
As shown in FIG. 16, the engagement shape portion of Configuration Example 5 includes a first engagement shape portion formed on the first adjacent surface 21e and a second engagement shape portion formed on the second adjacent surface 21f. , both have the same hook-shaped shapes 21g and 21h, and are formed continuously over the direction of relative movement.

In this configuration example 5, the hook-shaped shape 21h of the second adjacent surface 21f of one of the adjacent movable blades and the hook-shaped shape 21g of the first adjacent surface 21e of the other movable blade are engaged with each other. do. Here, with respect to the first adjacent surface 21e, which is the wall surface of the gripping space 30, the two adjacent surfaces 21e and 21f move in one direction (downward direction in the figure) along the direction perpendicular to the relative movement of the two adjacent surfaces 21e and 21f (vertical direction in the figure). Relative displacement is regulated by the hooked shape 21h of the second adjacent surface 21f. Therefore, the object to be grasped is grasped in the grasping space 30 formed by being surrounded by the movable blades 21A to 21F, and the object to be grasped is moved in the one direction along the axial direction of the grasping space 30 (perpendicular direction of relative movement). In this case, the movable blades 21A to 21F are less likely to be displaced in the direction perpendicular to the relative movement or to change their attitudes, and the occurrence of a situation that hinders expansion/contraction of the grasping space 30 is suppressed.

Configuration Example 5 has the advantage that the manufacturing process of the iris gripper 20 can be simplified because it is easy to engage the hook-shaped shapes 21h of one of the adjacent movable blades.
Since the first adjacent surface 21e is not restricted from being displaced relative to the one direction (upward direction in the figure), it can be displaced along the axial direction of the gripping space 30 (perpendicular direction of relative movement). When the gripped object is moved in a direction opposite to the one direction, the movable blades 21A to 21F are likely to shift their positions in the direction perpendicular to the relative movement or change their attitudes. However, if the application of the iris gripper 20 of Configuration Example 5 is an application in which the gripped object is not moved in the direction opposite to the one direction, it can be adequately handled.

Further, even when the hook-shaped engaging portions 21g and 21h as in Configuration Example 5 are employed, as shown in FIG. is formed, the relative displacement of the first adjacent surface 21e in the direction opposite to the one direction (upward direction in the drawing) can be restricted. Therefore, the object to be grasped is grasped in the grasping space 30 formed by being surrounded by the movable blades 21A to 21F, and the object to be grasped is moved in any direction along the axial direction of the grasping space 30 (perpendicular direction of relative movement). Even in such a case, the movable blades 21A to 21F are less likely to shift their positions in the direction orthogonal to the relative movement or to change their attitudes, and the occurrence of a situation that hinders expansion/contraction of the grasping space 30 is suppressed.

[Embodiment 2]
Next, another embodiment (hereinafter referred to as "second embodiment") in which the gripping device according to the present invention is applied as an end effector of a robot arm will be described.
The end effector of the first embodiment described above is formed by being surrounded by the movable blades 21A to 21F by moving the adjacent surfaces of the movable blades 21A to 21F facing each other. By reducing the gripping space 30, the iris gripper 20 allows the movable blades 21A to 21F to contact and grip the outer peripheral surface of the object to be gripped. On the other hand, in the end effector of Embodiment 2, a plurality of movable members annularly arranged so as to be adjacent to each other move in the radial direction with the adjacent surfaces of the adjacent movable members facing each other. The radially outer end portions of the plurality of movable members abut against the inner wall surface of the object to be grasped, thereby grasping the object to be grasped. In the following description, points different from the above-described first embodiment will be mainly described, and descriptions of points similar to the above-described embodiment will be omitted.

FIG. 18 is a perspective view showing the main configuration of an iris gripper 120 for gripping the inner wall surface of an object to be gripped, which is used as an end effector of the robot arm 10. As shown in FIG.
FIG. 19 is a plan view of the six movable blades 121A, 121B, 121C, 121D, 121E, and 121F that constitute the iris gripper 120, viewed from the side facing the movable disk.
FIG. 20 is a plan view showing the movable disk 122 that constitutes the iris gripper 120. As shown in FIG.
FIG. 21 is a plan view showing the stationary disc 123 that constitutes the iris gripper 120. FIG.
FIG. 22 is a plan view showing the fixed ring 129 that constitutes the iris gripper 120. FIG.

The iris gripper 120 of the second embodiment includes six flat plate-shaped movable blades 121A, 121B, 121C, 121D, 121D, 121B, 121D, 121B, 121D, 121B, 121D, 121D, 121A, 121B, 121C, 121D, 121D, 121A, 121B, 121D, 121D, 121A, 121D, 121D, 121D, 121A, 121D, and 121D. 121E and 121F. The movable blades 121A to 121F of Embodiment 2 are all the same member, and an arm portion 121k is provided on the outer peripheral portion of the blade. When gripping an object to be gripped, the arm portion 121k moves in the radial direction along with the movement of the movable blades 121A to 121F and comes into contact with the inner wall surface of the object to be gripped.

In the iris gripper 120 of the second embodiment, six movable blades 121A to 121F are annularly arranged on the same plane as in the first embodiment described above. Further, in the iris gripper 120 of the second embodiment, as in the first embodiment described above, the six movable blades 121A to 121F are moved while the adjacent surfaces (side surfaces of the movable blades) between the adjacent movable blades are moved relative to each other. moves in the same plane. By this movement, the outer ends of the arm portions 121k of the six movable blades 121A to 121F are accommodated within the surfaces of the movable disk 122 and the fixed disk 123, and the outer ends of the arm portions 121k are moved to the outside as shown in FIG. It is possible to switch between a protruding state in which the ends protrude out of the surfaces of the movable disk 122 and the fixed disk 123 . In the second embodiment, when the movable blades 121A to 121F are in the accommodated state, the space 130 formed by being surrounded by the movable blades 121A to 121F is closed, and the movable blades 121A to 121F are in the projected state. When it is taken, the space 130 formed by being surrounded by the movable blades 121A to 121F is opened.

Also, in the iris gripper 120 of the second embodiment, as described above, the six movable blades 121A to 121F annularly arranged on the same plane are sandwiched from both sides of the flat plate surface. 122 and a fixed disk 123 as a fixed member are arranged. The iris gripper 120 is attached to the end portion 15 via a fixed disc 123 . Further, in Embodiment 2, a fixed ring 129 is arranged to hold the movable disk 122 between itself and the fixed disk 123 .

As shown in FIG. 21, the fixed disc 123 is formed with long guide holes 123a to 123f as restricting portions for restricting the moving directions of the movable blades 121A to 121F. The movable blades 121A to 121F of the second embodiment are also formed with guide projections similar to the guide projections 21a of the first embodiment described above. A protrusion enters. As a result, when a moving force is applied to each of the movable blades 121A to 121F, each of the movable blades 121A to 121F is guided along each of the guide long holes 123a to 123f by the respective guide projections, thereby moving in a predetermined moving direction. Moving.

In the second embodiment as well, the elongated guide holes 123a to 123f are linear, and the guide projections of the movable blades 121A to 121F are elongated along the elongated guide holes 123a to 123f. The movable blades 121A to 121F that move while being guided by the long guide holes 123a to 123f move in parallel in the longitudinal direction of the long guide holes 123a to 123f, respectively.

The movable disk 122 is configured to be rotatable as in the first embodiment described above. Although illustration of a drive system is omitted in FIG. 18, the movable disc 122 is rotated by receiving a driving force from a drive motor as a driving means fixed to the fixed disc 123 . As shown in FIG. 20, the movable disk 122 is formed with long transmission holes 122a-122f for transmitting the moving force to the respective movable blades 121A-121F. The projections to be transmitted 121b of the movable blades 121A to 121F enter the long transmission holes 122a to 122f. As a result, when the movable disk 122 is rotated by the driving force of the drive motor, the moving force is applied to the projections 121b of the movable blades 121A to 121F to be pushed by the inner wall surfaces of the long transmission holes 122a to 122f of the movable disk 122. Granted. As a result, each movable blade 121A to 121F is given a moving force in a predetermined moving direction, and each movable blade 121A to 121F moves in a predetermined moving direction.

In the second embodiment, the six movable blades 121A to 121F are moved by one rotational input, but the six movable blades 121A to 121F are moved by two or more rotational inputs. may Also, the control of the movable blades 121A to 121F is the same as the opening/closing control of the iris gripper 20 in the first embodiment described above.

When the movable disk 122 rotates counterclockwise in FIG. 18 by the driving force of the drive motor, the movable blades 121A to 121F are guided along the guide slots 123a to 123f of the fixed disk 123 and move in parallel. . As a result, the outer ends of the arm portions 121k of the six movable blades 21A to 21F move radially outward. When the outer end of the arm portion 121k comes into contact with the inner wall surface of the object to be grasped, the object to be grasped can be grasped. On the other hand, when the movable disk 122 rotates in the clockwise direction in FIG. 18 by the driving force of the driving motor, each of the movable blades 21A to 21F moves in parallel, and the outer ends of the arms 121k of the six movable blades 21A to 21F move. moves radially inward. Then, the outer ends of the arm portions 121k of the six movable blades 121A to 121F are accommodated within the surfaces of the movable disk 122 and the fixed disk 123, respectively.

When the robot arm 10 grips a gripped object having grooves or holes (in this case, it is assumed to be a hollow cylindrical gripped object), the iris gripper 120 in the accommodated state is rotated around each axis of the robot arm 10. is controlled to bring the iris gripper 120 into the cylindrical interior of the object to be grasped. In this state, the drive motor is driven to rotate the movable disk 122 counterclockwise in FIG. The outer end of the arm portion 121k comes into contact with the inner wall surface of the grasped object, and the grasped object is grasped.

According to the iris gripper 120 according to the second embodiment, the object to be gripped by the outer end portion of the arm portion 121k moving radially outward is brought into contact with the outer end portion of the arm portion 121k. The center position of the hexagon with the outer end as the vertex (that is, the rotation axis of the movable disk 122) is approached, and finally, the center position of the object to be grasped is aligned with the center position and grasped. Therefore, there is no variation in the gripping position of the gripped object on the iris gripper, and the accuracy of the gripping position is high.

Further, each of the movable blades 21A to 21F in the iris gripper 120 of the second embodiment has two adjacent surfaces facing each other between the adjacent movable blades, in the same manner as in the above-described first embodiment. A convex shape as a second shape engaging portion is formed on the first adjacent surface, and a groove shape as a first shape engaging portion is formed on the first adjacent surface. Each of the movable blades 121A to 121F is arranged in a ring by engaging with each other by inserting the convex shape on the second adjacent surface of the adjacent movable blade into the groove shape formed on the first adjacent surface. .

Therefore, in the second embodiment as well, when an object to be grasped is grasped by the outer end of the arm portion 121k and the object to be grasped is lifted along the rotation axis direction of the movable disk 122, the six movable blades 121A to Even if a load (external force) in that direction is applied to 121F, the two adjacent surfaces facing each other engage with each other in a convex shape and a groove shape, and relative displacement in the direction orthogonal to relative movement is restricted. . Therefore, it is difficult for the movable blades 121A to 121F to shift in the direction or to change their posture. Therefore, even if a load (external force) is applied in that direction to the movable blades 121A to 121F, it is possible to ensure appropriate relative movement between the adjacent surfaces of the movable blades, and the outer end of the arm portion 121k protrudes. , it is possible to avoid a situation that hinders the accommodation operation.

The configuration of the first shape engaging portion and the second shape engaging portion of each of the movable blades 121A to 121F in Embodiment 2 is the configuration of each of Configuration Examples 1 to 5 in Embodiment 1 described above, or other configurations. It can be adopted as appropriate.

In the iris gripper 120 of the second embodiment, as in the first embodiment described above, the first shape engaging portion and the second shape engaging portion of each of the movable blades 121A to 121F are engaged with each other. Although a configuration is adopted in which relative displacement in the direction orthogonal to relative movement is restricted, this configuration is not essential. That is, the movable blades 121A to 121F are annularly arranged so as to be adjacent to each other, and by moving the adjacent surfaces of the adjacent movable blades to face each other, the outer ends of the respective movable blades 121A to 121F move radially. As long as it is configured to move to the direction perpendicular to the relative movement, the configuration in which the relative displacement in the direction perpendicular to the relative movement is restricted need not be employed.

1: Parts assembly system 10: Robot arm 11: Base part 12: Arm support part 13: Arm part 14: Hand part 15: Hand part 20, 120: Iris grippers 21A to 21F, 121A to 121F: Movable blade 21a: Guide projection 21b, 121b: transmitted projection 21c: groove shape 21d: convex shape 21e: first adjacent surface 21f: second adjacent surface 21g-21j: hook shape 22, 122: movable discs 22a-22f, 122a-122f: transmission length Holes 23, 123: Fixed discs 23a to 23f, 123a to 123f: Long guide hole 24: Transmission gear member 25: Motor gear 26: Drive motor 27: Rotation restriction frame 28: High friction material 30: Grasping space 121k: Arm portion 129: Fixed ring 130: Space

JP 2017-132032 A

Claims (9)

A plurality of movable members annularly arranged so as to be adjacent to each other are moved so that the adjacent surfaces of the adjacent movable members face each other, thereby reducing the holding space formed by being surrounded by the plurality of movable members. and a grasping device for grasping an object to be grasped in the grasping space,
The first engaging shape portion formed on the first adjacent surface, which is the wall surface of the gripping space, of the two adjacent surfaces facing each other between the adjacent movable members is the wall surface of the gripping space, among the two adjacent surfaces. A direction perpendicular to the relative movement direction of the two adjacent surfaces and parallel to the adjacent surfaces with respect to the second engaging shape formed on the second adjacent surface that does not become Alternatively, the two adjacent surfaces are engaged so that relative displacement in both directions is restricted , and relative displacement in the direction in which the two adjacent surfaces are separated from each other is also restricted with respect to the second engaging shape portion. A grasping device, characterized in that it engages such that : The gripping device of claim 1 , wherein
the first engagement shape portion has a groove shape extending in the relative movement direction,
The gripping device, wherein the second engagement shape portion has a convex shape that engages with the groove shape. 3. The gripping device according to claim 1 or 2 ,
The gripping device, wherein the first adjacent surface is a high-friction surface that increases frictional force in a direction perpendicular to the direction of relative movement and parallel to the adjacent surface . In the gripping device according to any one of claims 1 to 3 ,
The plurality of movable members are flat members,
a fixed member facing one flat plate surface of the plurality of movable members and provided with a restricting portion that restricts the moving direction of the plurality of movable members;
A gripping device, comprising: a moving force transmission member that faces the other flat plate surface of the flat plate member and transmits a moving force in the moving direction to the plurality of movable members. A gripping device according to claim 4 , wherein
a driving means for applying a driving force for moving the moving force transmission member;
A grasping device, wherein the moving force in the moving direction is transmitted to the plurality of movable members in conjunction with the movement of the moving force transmission member. A gripping device according to claim 5 , wherein
A gripping device comprising torque control means for controlling driving of the driving means based on the output torque of the driving means. A gripping device according to claim 5 or 6 ,
A grasping device, comprising: information acquisition means installed on the movable member for acquiring information on the movable member or the object to be grasped. A gripping device according to claim 7 , wherein
The information acquisition means is contact pressure detection means for detecting contact pressure with the object to be grasped,
A gripping device comprising contact pressure control means for controlling driving of the drive means based on a detection result of the contact pressure detection means. A robot arm equipped with a gripping device that grips an object to be gripped,
A robot arm using the gripping device according to any one of claims 1 to 8 as the gripping device.

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