JP2023041344A - Hand mechanism of robot - Google Patents

Abstract

To provide a hand mechanism that is configured so that fingertips of three fingers brought into 120° states can be concentrated at one point to grip a comparatively small object.SOLUTION: A hand mechanism 10A comprises: a fixed finger 11 fixed to a base part 20 so that the finger points to a predetermined reference point; two turning fingers 12 and 13; a finger turning mechanism 30, provided among the turning fingers 12 and 13 and the base part 20, which enables the turning fingers 12 and 13 to turn in an XY plane; and finger direction determining mechanisms 34 and 36, provided among the turning fingers 12 and 13 and the base part 20, which determines directions of the turning fingers 12 and 13. In a 120° state. the turning fingers 12 and 13 point to the reference point, and a line connecting the fixed finger 11 to the reference point is identical in length to a line connecting the turning fingers 12 and 13 to the reference point.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hand mechanism attached to a robot arm for use, and more particularly to a hand mechanism having three or more fingers.

Conventionally, various hand mechanisms have been used according to purposes. For example, as a hand mechanism intended to grip objects of various sizes and shapes, the one described in Non-Patent Document 1 is used.

As shown in FIG. 9, the hand mechanism 100 described in Non-Patent Document 1 includes a base 101 rotatably attached to the tip of a robot arm, a fixed finger 102 fixed to the base 101, and an attachment surface of the base 101 ( and two pivot fingers 103, 104 attached to the base 101 so as to pivot in a plane parallel to the lower surface).

As shown in FIG. 10, the three fingers 102, 103, and 104 are in a 0° state in which the three fingers 102, 103, and 104 are aligned, and from the 0° state, the two turning fingers 103 and 104 are respectively rotated. A 120° state obtained by turning 120° and a 180° state obtained by further turning the two turning fingers 103 and 104 by 60° from the 120° state can be obtained. The 120° state is preferable when gripping a relatively small object. In the 120° state, the tips (fingertips) of the three fingers 102, 103, and 104 can grip an object as if pinched.

“Multipurpose Robot Hand BarrettHand BH8-282”, [online], Japan Binary Co., Ltd., [searched on July 19, 2021], Internet <URL: http://www.nihonbinary.co.jp/Products/Robot /BarrettHand.html>

In the above-described conventional hand mechanism 100, when the three fingers 102, 103, 104 that are in the 120° state are uniformly bent, the three fingertips do not come together at one point. This is because no matter how the two pivot fingers 103, 104 are pivoted, they are not symmetrical about the pivot axis 105 of the base 101 relative to the robot arm. For this reason, in the hand mechanism 100, when three fingertips are gathered at one point to grasp a relatively small object, the finger opening/closing drive mechanism for the swiveling finger or the fixed finger or both of them has two or more degrees of freedom. The degree of freedom must be given and the degree of opening and closing of the fingers must be adjusted as appropriate. This contributes to complicating the finger mechanism and control.

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a hand mechanism capable of gripping a relatively small object.

In order to solve the above problems, the hand mechanism according to the present invention, which is attached to a robot arm and used, includes a base having an attachment surface attached to the tip of the robot arm, and a hand mechanism fixed to the base so as to face a predetermined reference point. a fixed finger, two turning fingers, and a finger turning mechanism which is provided between each of the two turning fingers and the base and enables turning of the turning fingers within a reference plane parallel to the mounting surface. and a finger direction determination mechanism provided between each of the two turning fingers and the base to determine the orientation of the turning finger, wherein the fixed finger and the two turning fingers are: (1) the two turning fingers; A 0° state in which the fixed finger and the two turning fingers are aligned so that the fixed finger is positioned between them; and (3) a 180° state in which each of the two turning fingers faces each of the two turning fingers in the 0° state. In the 120° state, the turning finger faces the reference point, and the line connecting the fixed finger and the reference point and the line connecting the turning finger and the reference point have the same length. do.

The finger turning mechanism of the hand mechanism has, for example, a motor fixed to the base and having an output shaft extending in a direction perpendicular to the reference plane, one end and the other end, and one end connected to the output shaft via a reduction gear. a swivel arm fixed and having the other end rotatably connected to the swivel finger, the output shaft extending from the swivel finger in the 0° state and parallel to a line connecting the fixed finger and the reference point; are on parallel lines.

The finger direction determination mechanism of the hand mechanism includes, for example, a guide flap rotatably connected to the base, and a sliding portion slidable relative to the guide flap and fixed to the turning finger, The rotation axis of the guide flap can be arranged at the intersection of the line connecting the turning finger in the 120° state and the reference point and the parallel line.

The hand mechanism further includes an additional fixed finger fixed to the base so as to face the reference point, the additional fixed finger facing the fixed finger and connecting a line connecting the fixed finger and the reference point, and a line connecting the additional fixed finger and the reference point. You may have the structure that the line which connects a reference point is the same length.

The base of the hand mechanism may be rotatably attached to the tip of the robot arm. In this case, a reference point can be set on the pivot axis of rotation for the robot arm.

According to the present invention, it is possible to provide a hand mechanism capable of gripping a relatively small object by converging the fingertips of three fingers in the 120° state.

FIG. 4 is a perspective view of the hand mechanism in the 120° state according to the embodiment of the present invention; FIG. 4 is a perspective view of the hand mechanism in the 0° state according to the embodiment of the present invention; FIG. 4 is a perspective view of the hand mechanism in the 180° state according to the embodiment of the present invention; 1 is an exploded perspective view of a hand mechanism according to an embodiment of the present invention; FIG. FIG. 4 is a schematic plan view showing the positional relationship of main members constituting the hand mechanism according to the embodiment of the present invention, where (A) is a schematic plan view in the 0° state, (B) is a schematic plan view in the 120° state; (C) is a schematic plan view in the 180° state. FIG. 2 is a plan view of a hand mechanism according to an embodiment of the present invention, where (A) is a plan view at 0° state, (B) is a plan view at 120° state, and (C) is a plan view at 180° state. . FIG. 11 is a perspective view of a hand mechanism according to a first modified example of the present invention; FIG. 11 is a perspective view of a hand mechanism according to a second modified example of the present invention; 1 is a perspective view of a conventional hand mechanism; FIG. FIG. 11 is a plan view showing a turning operation of a conventional hand mechanism;

Hereinafter, embodiments of the hand mechanism according to the present invention will be described with reference to the accompanying drawings.

[Example]
1 to 4 show a hand mechanism 10A according to an embodiment of the present invention having three identical fingers (fixed finger 11 and two turning fingers 12, 13). The hand mechanism 10A is used by being attached to the tip of a robot arm (not shown) so as to be able to turn around the turning axis R1. The hand mechanism 10A is in the 120° state shown in FIGS. 1 and 6B, the 0° state shown in FIGS. 2 and 6A, and the 180° state shown in FIGS. 3 and 6C. ° state can be taken.

As shown in FIG. 1, the hand mechanism 10A includes a base 20 having a shape symmetrical with respect to the YZ plane including the pivot axis R1. The base 20 has a mounting surface 20a parallel to the XY plane and two motor housing chambers 21,21. Each motor accommodation chamber 21 accommodates a motor having an output portion rotatable around an output shaft R2 (see FIG. 4) extending in the Z direction. An appropriate speed reducer 22 is provided at the output of each motor.

The hand mechanism 10A further includes a substantially plate-shaped fixed finger support portion 23 that rotatably supports the fixed finger 11 at its upper end. The fixed finger 11 faces the pivot axis R1, and rotates with respect to the fixed finger support 23 by the action of the fixed finger opening/closing drive mechanism 24 provided on the outward main surface of the fixed finger support 23. . In other words, the fixed finger 11 is opened and closed by the action of the fixed finger opening/closing drive mechanism 24 . In this embodiment, the fixed finger opening/closing drive mechanism 24 has one degree of freedom.

In this specification, a combination of the fixed finger 11 and the fixed finger support portion 23 is sometimes called a "fixed finger".

The hand mechanism 10A further includes two swivel arms 30, 30 extending within the XY plane. Each turning arm 30 has one end and the other end, one end of which is fixed to the output portion of the motor via the speed reducer 22, and the other end of which rotates to a connecting portion 33 (turning finger support portion 31) described later. freely connected. That is, each turning arm 30 can turn about the output shaft R2 with respect to the base portion 20, and can turn about the turning axis R3 (see FIG. 4) with respect to the connecting portion 33 (turning finger support portion 31). It is free.

When the motor rotates in a certain direction, the swivel arm 30 swivels in the XY plane by an angle corresponding to the amount of rotation and the reduction ratio of the speed reducer 22, and the positional relationship (state) of the three fingers 11, 12, and 13 is It changes like 0° state→120° state→180° state. On the other hand, when the motor rotates in the opposite direction, the swivel arm 30 swivels in the XY plane by an angle corresponding to the amount of rotation and the speed reduction ratio, and the positional relationship between the three fingers 11, 12, and 13 is 180°. It changes from 120° state to 0° state.

The hand mechanism 10A further includes a substantially plate-like turning finger support portion 31 that rotatably supports the turning finger 12 at its upper end. The swing finger support 31 has a connecting portion 33 protruding from its inward main surface, and is rotatably connected to the swing arm 30 by this connecting portion 33 . The swing finger 12 rotates with respect to the swing finger support 31 by the action of a swing finger opening/closing drive mechanism 32 provided on the outward surface of the swing finger support 31 . In other words, the swing finger 12 is opened and closed by the action of the swing finger opening/closing drive mechanism 32 . In this embodiment, the degree of freedom of the turning finger opening/closing drive mechanism 32 is one.

As a matter of course, the hand mechanism 10A also includes a substantially plate-like turning finger support portion 31 that rotatably supports the turning finger 13 at its upper end.

In this specification, a combination of the turning finger 12 and the turning finger support portion 31 and a combination of the turning finger 13 and the turning finger support portion 31 are sometimes referred to as a "turning finger".

The hand mechanism 10A further includes two substantially plate-shaped guide flaps 36, 36 extending in the Z direction. Each guide flap 36 has two connecting portions 37 and 38 (see FIG. 4) protruding from one main surface thereof and is pivotally connected to the base portion 20 by these. That is, each guide flap 36 is rotatable with respect to the base portion 20 around the rotation axis R4 (see FIG. 4). Each guide flap 36 further has two parallel guide bars 35, 35 extending along the one main surface. The two guide rods 35, 35 are fixed to the main surface of the guide flap 36 at both ends thereof.

The hand mechanism 10A further includes two sliding portions 34,34. Each sliding portion 34 has two penetrating tunnels 34a, 34a into which guide rods 35, 35 are inserted so that the sliding portion 34 can slide along the guide rods 35, 35. As shown in FIG. Further, the turning finger support portions 31 are fixed to the end portions of the sliding portions 34 closer to the connecting portions 37 and 38 so as to form a right angle with each other. As a result, the turning fingers 12 and 13 supported by the turning finger support portion 31 always face the same direction as the sliding direction of the sliding portion 34 (that is, the extending direction of the guide bars 35 and 35). there is

Next, a method of designing the hand mechanism 10A will be described with particular reference to FIG. Note that the fixed finger 11 in FIG. The turning fingers 12 and 13 in the figure include a turning finger support portion 31, a turning finger opening/closing driving mechanism 32, a connecting portion 33, and a sliding portion . Also, the guide flap 36 in the figure includes guide rods 35 and 35 and connecting portions 37 and 38 .

First step: Determine the actual dimensions of base 20, fixed finger 11 and pivot fingers 12,13.

Second step: Draw a circle C centered on the pivot axis R1. At this time, the size of the circle C is made to correspond to the actual size of the base 20 . In addition, the position of the turning axis R1 corresponds to the "reference point" of the present invention.

3rd step: drawing a fixed finger 11 so as to be in contact with the circle C; At this time, the widthwise dimension W of the fixed finger 11 is made to correspond to the actual dimension.

Fourth step: Assuming a 0° state, draw turning fingers 12 and 13 on both sides of the fixed finger 11 . At this time, the widthwise dimension W of the turning fingers 12 and 13 is the same as the widthwise dimension W of the fixed finger 11 .

Fifth step: The width direction center of the turning fingers 12 and 13 in the 0° state is set to the position of the rotation axis R3 in the 0° state (see FIG. 5A), and extends from this position (R3). Draw two parallel lines L2, L2 parallel to the line L1.

Sixth step: Draw two lines L3, L3 that pass through the reference point (R1) and form an angle of 120° with respect to the line L1.

Seventh step: The intersection of the line L3 and the circle C is the position of the rotation axis R3 in the 120° state (see FIG. 5B), and the intersection of the line L3 and the line L2 is the position of the rotation axis R4. and

Eighth step: A point on the line L2 at which the distance from the position of the rotation axis R3 in the 0° state is equal to the distance from the position of the rotation axis R3 in the 120° state is set as the position of the output shaft R2.

Ninth step: determining the dimensions of the pivot arm 30 based on the distance between the positions of the pivot axis R2 and the pivot axis R3.

If the positions of the output shaft R2 and the rotation shafts R3 and R4 are determined in this way, the three fingers 11, 12 and 13 face the reference point (R1) and the reference point ( R1) to each finger 11, 12, 13 become equal (see FIG. 5(B)). That is, according to the first to ninth steps, it is possible to realize the hand mechanism 10A that can grip an object as if pinched on the turning axis R1 in the 120° state.

FIG. 6 is a plan view of the hand mechanism 10A (three fingers 11, 12, 13 are omitted) corresponding to FIG. As can be seen from the figure, in this embodiment, the motor, speed reducer, and swivel arm 30 allow the swivel fingers 12 and 13 to swivel within a plane parallel to the mounting surface 20a. Therefore, in this embodiment, the motor, the speed reducer and the turning arm 30 correspond to the "finger turning mechanism". Further, in this embodiment, the orientation of the turning fingers 12 and 13 is determined not by how much the turning arm 30 has turned with respect to the base 20, but how much the guide flap 36 has turned with respect to the base 20. be done. Therefore, in this embodiment, the guide flap 36 and the sliding portion 34 that slides along it correspond to the "finger direction determination mechanism".

[First modification]
Although the embodiments of the hand mechanism according to the present invention have been described above, the hand mechanism according to the present invention is not limited to this. good.

The hand mechanism 10B according to this modification includes three fingers (a fixed finger 11 and two turning fingers 12 and 13) having the same structure, and is configured to rotate about a turning axis R1 (not shown). Used by attaching to the tip of the robot arm.

As shown in FIG. 7, the hand mechanism 10B includes a base portion 40 having a shape symmetrical with respect to the YZ plane including the rotation axis R1, a fixed finger support portion 41 supporting the fixed finger 11 at its upper end, and a fixed finger support portion 41 at its upper end. , two turning finger support portions 42 for supporting the turning fingers 12 and 13, two guide rods 44 and 44, and a guide plate 50 having a surface 50a parallel to the XY plane. Although not shown, the hand mechanism 10B also includes a fixed finger opening/closing drive mechanism provided on the fixed finger support portion 41 and a turning finger opening/closing drive mechanism provided on the turning finger support portion 42 .

Each guide rod 44 has a connecting portion 43 and is rotatably connected to the base portion 40 by this connecting portion 43 . That is, each guide rod 44 is rotatable with respect to the base portion 20 around the rotation axis R4.

The guide plate 50 has two guide grooves 51, 51 formed on the surface 50a. The circular arc shape of each guide groove 51 is the same as the trajectory of the rotation axis R3 when the turning fingers 12 and 13 are turned from the 0° state to the 180° state in the hand mechanism 10A according to the embodiment (Fig. 5 reference). It can also be said that the arc shape of each guide groove 51 is an arc with a central angle of 180° around the rotation axis R2. Each guide groove 51 engages with a projection provided at the lower end of the turning finger support portion 42 to guide the projection.

The turning finger support 42 and the guide rod 44 constitute a linear motion actuator. That is, the turning finger support portion 42 can move linearly along the guide rod 44 . When the linear motion actuators (42, 44) operate to move the turning finger support 42 away from the rotation axis R3, the turning finger support 42 moves toward the guide groove 51 while the guide rod 44 rotates about the rotation axis R4. to approach the fixed finger support portion 41 . On the other hand, when the linear motion actuators (42, 44) operate and the turning finger support portion 42 approaches the rotation axis R3, the turning finger support portion 42 guides while the guide rod 44 rotates around the rotation axis R4. It moves along the groove 51 and moves away from the fixed finger support part 41.例文帳に追加

Thus, in this modification, the positional relationship between the three fingers 11, 12, 13 is changed by operating the direct acting actuators (42, 44). In addition, in this modified example, the direct-acting actuators (42, 44) and the guide groove 51 correspond to the "finger turning mechanism". Further, in this modified example, the direct acting actuators (42, 44) correspond to the "finger direction determination mechanism".

As with the hand mechanism 10A according to the embodiment, according to the hand mechanism 10B according to the present modification, it is possible to grip an object as if pinching it on the turning axis R1 in the 120° state.

[Second modification]
The hand mechanism according to the present invention may have a configuration like the hand mechanism 10C shown in FIG.

The hand mechanism 10C according to this modification further includes another fixed finger 14, further includes a fixed finger support portion 45 for supporting the fixed finger 14, and the shape of the base portion 40 is different from that of the fixed finger. It is different from the hand mechanism 10B in that it has a shape that allows attachment of the support portion 45, but is common to the hand mechanism 10B in other respects. The fixed finger 14 faces the fixed finger 11 and is provided at a position where the distance from the pivot axis R1 to the fixed finger 14 is equal to the distance from the pivot axis R1 to the fixed finger 11 .

According to the hand mechanism 10C according to this modification, the three fingers 11, 12, 13 and the fixed finger 14, which are in the 120° state, can be used to grip the object as if pinching it on the rotation axis R1. can be done.

[Other Modifications]
The hand mechanism according to the present invention may be used by being non-rotatably attached to a robot arm. Also, each of the fixed fingers 11 and 14 and the turning fingers 12 and 13 may have one or more joints. Further, the fixed finger opening/closing drive mechanism 24 and the rotating finger opening/closing drive mechanism 32 may have two or more degrees of freedom.

10A, 10B, 10C Hand Mechanism 11 Fixed Fingers 12, 13 Turning Finger 20 Base 21 Motor Housing Chamber 22 Reduction Gear 23 Fixed Finger Support Section 24 Fixed Finger Opening/Closing Drive Mechanism 30 Turn Arm 31 Turning Finger Support Section 32 Turning Finger Opening/Closing Drive Mechanism 33 Connecting portion 34 Sliding portion 35 Guide rod 36 Guide flaps 37, 38 Connecting portion 40 Base portion 41 Fixed finger support portion 42 Turning finger support portion 43 Connecting portion 44 Guide rod 45 Fixed finger support portion 50 Guide plate 51 Guide groove

Claims (4)

A hand mechanism attached to a robot arm and used,
a base having an attachment surface attached to the tip of the robot arm;
a fixed finger fixed to the base so as to face a predetermined reference point;
two pivoting fingers and
a finger turning mechanism provided between each of the two turning fingers and the base, and capable of turning the turning fingers within a reference plane parallel to the mounting surface;
a finger direction determining mechanism provided between each of the two turning fingers and the base portion for determining the orientation of the turning fingers;
with
The fixed finger and the two pivot fingers are
(1) a 0° state in which the fixed finger and the two turning fingers are aligned so that the fixed finger is positioned between the two turning fingers;
(2) a 120° state in which a line connecting the fixed finger and the reference point and a line connecting each of the two turning fingers and the reference point form an angle of 120°;
(3) each of the two turning fingers can take a 180° state facing each of the two turning fingers in the 0° state;
In the 120° state, the turning finger faces the reference point, and the line connecting the fixed finger and the reference point and the line connecting the turning finger and the reference point have the same length. Characterized hand mechanism. The finger turning mechanism is
a motor fixed to the base and having an output shaft extending in a direction perpendicular to the reference plane;
a turning arm having one end and the other end, the one end being fixed to the output shaft via a speed reducer and the other end being rotatably connected to the turning finger;
including
the output shaft is on a parallel line extending from the turning finger in the 0° state and parallel to a line connecting the fixed finger and the reference point;
The finger orientation determination mechanism includes:
a guide flap rotatably connected to the base;
a sliding portion slidable relative to the guide flap and fixed to the turning finger;
including
2. A hand mechanism according to claim 1, wherein the rotation axis of said guide flap is located at the intersection of said parallel line and a line connecting said turning finger in the 120[deg.] state and said reference point. further comprising an additional fixed finger fixed to the base to face the reference point;
In the additional fixed finger, a line facing the fixed finger and connecting the fixed finger and the reference point and a line connecting the additional fixed finger and the reference point have the same length. The hand mechanism according to claim 1 or 2. the base is rotatably attached to the tip of the robot arm;
4. The hand mechanism according to any one of claims 1 to 3, wherein the reference point is on the pivot axis of pivoting with respect to the robot arm.

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