JP2024001616A - Robot finger and robot hand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot finger achieving downsizing and a high gripping force with a simple structure in comparison with a conventional method for fixing a wire to a pulley end part to rotate a pulley or a method for using interference driving to rotate the pulley.

SOLUTION: A robot finger 100 is used for a robot hand 1 and includes: a frame member 110 composing a finger part of the robot hand 1; a base part 100a including an axial member 50 freely rotatably supporting the frame member; a movable pulley 10 fixed to the frame member; a driving wire 20 for driving the frame member; and pulling means 40 for pulling a driving wire. One end of the driving wire is fixed to the base part, the other end of the driving wire is connected to the pulling means via the movable pulley, and at least the movable pulley, the driving wire, the axial member, and the pulling means compose a rotation mechanism 100b rotating the frame member.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a robot finger having a structure in which a frame member constituting a finger portion of a robot hand is driven by a wire, and a robot hand including such a robot finger.

In conventional wire-driven robot hands, a wire is fixed to the end of the pulley and the pulley is rotated, or an interference drive is used to rotate the pulley.

However, in order to output the gripping force necessary to firmly grip an object, it is necessary to increase the diameter of the pulley, making it difficult to downsize. Furthermore, when using interference drive, there is a problem that the number of wires increases or the arrangement of the wires becomes complicated.

The present invention achieves miniaturization and high gripping force with a simple structure compared to conventional methods of rotating a pulley by fixing a wire to the end of the pulley or rotating the pulley using interference drive. The object is to obtain a robot finger and a robot hand including such a robot finger.

(Item 1)
A robot finger used for a robot hand,
a frame member that constitutes a finger portion of the robot hand;
a base including a shaft member that rotatably supports the frame member;
a movable pulley fixed to the frame member;
a driving wire for driving the frame member;
and a pulling means for pulling the drive wire,
One end of the driving wire is fixed to the base, and the other end of the driving wire is connected to the tensioning means via the movable pulley,
A robot finger, wherein at least the movable pulley, the drive wire, the shaft member, and the tensioning means constitute a rotation mechanism for rotating the frame member.

(Item 2)
In the rotation mechanism, the movable pulley rotates around the shaft member due to the force of the tensioning means pulling the other end of the drive wire, and the frame member is accordingly moved in a direction in which the finger portions are bent. The robot finger according to item 1, wherein the robot finger is configured to rotate.

(Item 3)
The rotation mechanism progresses the bending of the fingers in response to the force with which the tension means pulls the other end of the drive wire, and the rotation mechanism advances the bending of the finger portions in response to the force with which the tension means pulls the other end of the drive wire. The robot finger according to item 2, wherein the direction of the applied force approaches the direction of the force that rotates the frame member.

(Item 4)
The movable pulley moves on a circumference centered on the shaft member and whose radius is the distance between the shaft member and the movable pulley,
The robot finger according to item 3, wherein the shaft member is arranged between the movable pulley and the tensioning means.

(Item 5)
The robot finger according to item 4, wherein a fixed pulley is attached to the base so as to be located between the movable pulley and the other end of the drive wire.

(Item 6)
A robot hand equipped with five robot fingers described in item 1.

According to the present invention, even if the structure is simple by using a movable pulley, the rotational force (gripping force when gripping an object) of the frame member that constitutes the fingers of the robot hand can be used as the drive force that drives the frame member. This makes it possible to double the tensile force of the wire without changing it. Further, it is possible to obtain a robot finger including a rotation mechanism that can further increase the rotation force of the frame member as the frame member rotates, and a robot hand including such a robot finger.

FIG. 1 is a plan view for explaining a robot hand 1 according to a first embodiment of the present invention, showing the external appearance of the robot hand 1 and a robot finger 100 (in an extended state) included in the robot hand 1. FIG. 2 is an exploded view of the robot finger 100 shown in FIG. 1 into its main components. FIG. 3 is a diagram showing a change in the posture of the robot finger 100 shown in FIG. 1, and shows a bending state of the robot finger 100 and a change in the direction of the tensile forces F1 and F2 acting on the movable pulley 10 of the robot finger 100. . FIG. 4 is a schematic diagram showing the layout of the drive wire 20 used in the robot finger 100 shown in FIG. It shows. FIG. 5 is a plan view showing a mechanism in which the rotational force of the frame member 110 of the robot finger 100 shown in FIG. 1 increases as the bending progresses.

The present invention will be explained below. It should be understood that the terms used herein have the meanings commonly used in the art, unless otherwise specified. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification (including definitions) will control.

As used herein, "about" refers to a range of ±10% of the following number.

In addition, a "pulley" is a mechanism that includes a rotatable disc member having a rotating shaft and a housing member that supports the disc member, and is configured so that the housing member is connected to another structure. It refers to In particular, a "fixed pulley" is generally referred to as a fixed pulley, and refers to a pulley whose disc rotation axis (rotation center) is fixed, and the direction of a linear member such as a wire or rope passing through the pulley. used to change. In addition, a "moving pulley" refers to a pulley whose disk rotation axis (rotation center) is not fixed, and which can be moved in the opposite direction to the load with a force of about 1/2 of the load applied to the pulley. Say something. In addition, the configuration in which the movable pulley is moved in the opposite direction to the direction of the load includes a configuration in which the movable pulleys are combined to include a multiple pulley configuration in which a wire or rope passing through one movable pulley to which a load is directly applied is pulled by another movable pulley. be able to. For example, when moving a first-stage movable pulley to which a direct load is applied in a direction opposite to the direction of the load using a second-stage movable pulley, the force is approximately 1/4 of the load applied to the first-stage movable pulley. The first stage movable pulley can be moved in the opposite direction to the direction of the load. In this multiple pulley configuration using movable pulleys, as the number of movable pulleys increases, the force that moves the movable pulley to the side opposite to the load decreases by half.

The present invention makes it possible not only to double the rotational force of the frame member that makes up the fingers of the robot hand without changing the tensile force of the drive wire that drives the frame member, but also to increase it as the frame member rotates. The task was to obtain a robot finger with a rotation mechanism that
A robot finger used for a robot hand,
a frame member that constitutes a finger portion of a robot hand;
a base including a shaft member that rotatably supports the frame member;
A movable pulley fixed to the frame member,
a driving wire for driving the frame member;
and a tensioning means for pulling the drive wire,
One end of the drive wire is fixed to the base, and the other end of the drive wire is connected to the tensioning means via a movable pulley,
The above problem is solved by providing a robot finger that includes at least a movable pulley, a drive wire, a shaft member, and a tensioning means to constitute a rotation mechanism for rotating a frame member. It is.

Therefore, as long as the robot finger of the present invention is equipped with a rotation mechanism that rotates the frame member constituting the finger portion of the robot hand using a movable pulley fixed to the frame member, the robot finger of the present invention is particularly suitable for other configurations. It is not limited.

The frame member constituting the finger portion of the robot hand may include one or more frame pieces, but the number of frame pieces may be arbitrary. For example, when imitating a human finger, three frame pieces are used to have two joints, but the present invention is not limited to this.

The drive wire may be of any form (material, number) as long as it is a wire.

The tensioning means can be of any form capable of pulling the drive wire. For example, the tensioning means may be a pneumatic or hydraulic cylinder (hydraulic type, hydraulic type, etc.), or may be a driving source such as a motor.

For example, in the rotation mechanism, the movable pulley rotates around the shaft member due to the force of the tensioning means pulling the other end of the drive wire, and the frame member accordingly rotates in the direction in which the finger portion bends. It is preferable that it be configured. In this case, since approximately twice the force with which the tensioning means pulls the movable pulley acts on the frame member, the force with which the tensioning means rotates the frame member in the bending direction of the fingers can be doubled by the movable pulley. can.

In addition, in the rotation mechanism, the bending of the fingers progresses according to the force with which the tensioning means pulls the other end of the drive wire, and the force acting on the movable pulley increases depending on the amount of tension pulled by the tensioning means. Preferably, the direction is arranged to approach the direction of the force causing the frame member to pivot.

In this case, as the bending of the finger progresses, the direction of the force acting on the movable pulley from the tensioning means via the drive wire approaches the direction of the force that rotates the frame member. It can be increased as the flexion of the finger progresses.

Furthermore, the movable pulley moves on a circumference centered on the shaft member and whose radius is the distance between the shaft member and the movable pulley, and the shaft member is disposed between the movable pulley and the tensioning means. You can leave it there.

This positional relationship among the movable pulley, the shaft member, and the tensioning means is an example of a specific configuration for realizing a rotation mechanism that increases the force for bending the finger as the finger progresses. The positional relationship that realizes the moving mechanism may be such that the tensioning means is located between the moving pulley and the shaft member.

Further, a fixed pulley may be attached to the base so as to be located between the movable pulley and the other end of the drive wire.

In this case, the fixed pulley (see fixed pulley 30 in FIG. 5) allows the direction of the force acting on the movable pulley via the drive wire to be close to the direction of the force that rotates the frame member. .

Furthermore, from the perspective of interference drive, the fixed pulley may also play a role in changing the combination of driving forces for each of the plurality of joints driven by the rotation mechanism including the fixed pulley.

For example, the robot finger of the present invention has a rotation mechanism that rotates the frame member (specifically, the frame piece) using a drive wire on both sides of the frame member (specifically, the frame piece) corresponding to the finger. If one each is installed, and the abduction and adduction of the finger are controlled by the amount of traction (pulling amount) of the drive wire (that is, the pair of drive wires) in the two rotation mechanisms, the external rotation Fixed pulleys may be used to maximize the amount of rotational force for rotation and internal rotation. Alternatively, the fixed pulley can be used when the rotation mechanism of the present invention is employed in a DIP joint or a PIP joint, and a wire route is set to generate an interference force in the MP joint.

Furthermore, when a fixed pulley is provided at the base as described above, by passing the other end of the drive wire located between the movable pulley and the tensioning means through the fixed pulley, the drive wire can be It becomes possible to prevent the other end side portion of the wire from coming into contact with the one end side portion of the drive wire between the movable pulley and the base. However, depending on the layout of the drive wire, contact between one end and the other end of the drive wire can be avoided even if the fixed pulley is not provided at the base.

Note that the material of each member constituting the robot finger included in the robot hand of the present invention may be a metal material such as iron or stainless steel, or may be other material such as a resin material, wood, or ceramic material. Furthermore, by using materials suitable for the required characteristics for each member, requirements for durability, weight reduction, reliability, etc. can be appropriately satisfied.

For example, the movable pulley, fixed pulley, shaft member, etc. are preferably made of metal, but the frame member is not limited to metal, and may be made of resin, wood, or ceramic.

As described above, the robot finger of the present invention is particularly limited as long as it is equipped with a rotation mechanism that rotates the frame member constituting the finger portion of the robot hand using a movable pulley fixed to the frame member. In the following embodiments, the rotating mechanism includes a fixed pulley fixed to a base that supports the frame member in addition to a movable pulley fixed to the frame member.

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view for explaining a robot hand 1 according to a first embodiment of the present invention. FIG. 1(a) shows the external appearance of the robot hand 1, and FIG. One included robot finger 100 (extended state) is shown.

As shown in FIG. 1(a), this robot hand 1 has one thumb robot finger 80 corresponding to the thumb of the hand and four robot fingers 100 corresponding to the four fingers other than the thumb of the hand. There is.

First, a robot finger 100 corresponding to four fingers other than the thumb will be described.

[Robot Finger 100]
The robot finger 100 corresponding to one finger (for example, the index finger) of the robot hand 1 includes a frame member 110 that constitutes the finger of the robot hand 1, and a shaft member 50 that rotatably supports the frame member 110. It includes a base 100a, a movable pulley 10 fixed to a frame member 110, a driving wire 20 for driving the frame member 110, and a tensioning means 40 for pulling the driving wire 20.

Here, one end 20a of the driving wire 20 is fixed to the base 100a by a fixing part 103, and the other end 20b of the driving wire 20 is connected to the tensioning means 40 via the movable pulley 10. It is fixed at 100a.

In this robot finger 100, at least the movable pulley 10, the drive wire 20, the shaft member 50, and the tensioning means 40 constitute a rotation mechanism 100b that rotates the frame member 110.

The main components of this robot finger 100 will be specifically explained below.

FIG. 2 is an exploded view showing the robot finger 100 shown in FIG. 1 into its main components, and FIG. 100a and a plan view showing the rotation mechanism 100b, and FIG. 2(b) is a perspective view showing the second frame piece 110b.

(Frame member 110)
The frame member 110 includes a first frame piece 110a corresponding to the tip of the finger, a third frame piece 110c corresponding to the root of the finger, and an intermediate portion between the tip and the root of the finger. It has a second frame piece 110b corresponding to the section.

Here, the frame member 110 is assumed to be a finger part as an index finger, and the first frame piece 110a corresponds to the part beyond the first joint (DIP joint) of a human finger, and the second frame piece 110a corresponds to the part beyond the first joint (DIP joint) of a person's finger. The piece 110b corresponds to the part between the first joint and the second joint (PIP joint) of a person's finger, and the third frame piece 110c corresponds to the part between the second joint and the third joint (MP joint) of the person's finger. It corresponds to the part between the joints).

The parts that make up the frame member 110 of the robot finger 100 will be described in detail below.

As shown in FIGS. 2(a) and 2(b), the second frame piece 110b includes a frame piece main body 111b, a frame piece connecting pin 112b provided at one end thereof, and a frame piece connecting pin 112b provided at the other end. A first frame piece 110a is rotatably supported by the frame piece connecting pin 112b, and a third frame piece 110c is rotatably supported by the frame piece connecting pin 113b. It is now possible to do so.

As shown in FIG. 2(a), the first frame piece 110a has a frame piece body 111a connected to the frame piece body 111b of the second frame piece 110b, and a tip grip part 113a provided on the tip side thereof. . Here, the tip gripping portion 113a corresponds to the fingertip of a person's hand that grips an object, and is fixed to the frame piece main body 111a with a fixing screw 114a. Further, the frame piece main body 111a is formed with a frame piece connecting hole 112a for inserting the frame piece connecting pin 112b of the second frame piece 110b. A locking clip 115b is attached to the frame piece connecting pin 112b of the second frame piece 110b inserted into the piece connecting hole 112a to prevent the frame piece connecting pin 112b from coming off from the frame piece connecting hole 112a. There is.

As shown in FIG. 2(a), the third frame piece 110c has a frame piece main body 111c connected to the frame piece main body 111b of the second frame piece 110b, and the movable pulley 10 is attached to the frame piece main body 111a. It is being Further, a frame piece connecting hole 112c for inserting the frame piece connecting pin 113b of the second frame piece 110b is formed on one end side of the frame piece main body 111c, and a frame piece connecting hole 112c for inserting the frame piece connecting pin 113b of the second frame piece body 110b is formed on the other end side of the frame piece main body 111c. A base connection hole 113c is formed into which the shaft member 50 of the base 100a is inserted.

Further, in the third frame piece 110c, the frame piece connecting pin 113b of the second frame piece 110b inserted into the frame piece connecting hole 112c is engaged so that the frame piece connecting pin 113b does not come out from the frame piece connecting hole 112c. The locking clip 104 is attached to the shaft member 50 of the base 100a which is fitted with the locking clip 114b and inserted into the base connecting hole 113c so that the shaft member 50 does not come off from the base connecting hole 113c. There is.

(Base 100a)
As shown in FIG. 2(a), the base 100a includes a base plate 101, a base cover 102 that partially covers the base plate 101, and a movable pulley 10 attached to the third frame piece 110c. A shaft member 50 that rotatably supports the frame piece main body 111a of the third frame piece 110c is attached to one end of the base plate 101, and one end of the drive wire 20 is attached to the other end of the base plate 101. A fixing part 103 for fixing to the base plate 101 is provided, and a tensioning means 40 is connected to the other end of the driving wire 20 as a wire driving end, and this tensioning means 40 has a driving wire for pulling the driving wire 20. An actuator as a source is connected. The drive source that pulls the other end of the drive wire 20 may be directly connected to the drive end, or may be a pneumatic or hydraulic drive source that is connected via a rod or the like. The cylinder may be a hydraulic type, hydraulic type, etc.). Note that in FIGS. 1, 2(a), and the like, the tensioning means 40 is provided at the distal end side of the base plate 101, which is the distal end portion of the base portion 100a, but the present invention is not limited thereto. The tensioning means 40 may be provided outside and away from the base 100a.

Further, a fixed pulley 30 is attached to the base plate 101 so that the direction of the driving wire 20 is changed when the driving wire 20 heading from the movable pulley 10 toward the tensioning means 40 passes through the fixed pulley 30. It has become.

Further, the robot finger 100 includes a rotation mechanism 100b that rotates the frame member 110 having such a configuration, and the rotation of the frame member 110 causes the robot finger 100 to bend and extend. .

3A and 3B are diagrams showing changes in the posture of the robot finger 100 shown in FIG. 1. FIG. 3A shows the robot finger 100 in a bent state, and FIG. It shows changes in the direction of the tensile forces F1 and F2 acting on the movable pulley 10 of the robot finger 100.

(Rotating mechanism 100b)
The rotation mechanism 100b includes a movable pulley 10 attached to the frame member 110 so as to rotate around the rotation axis Ra of the frame member 110, as shown in FIGS. 1(b) and 3(a), It has a driving wire 20 that passes through the moving pulley 10 and a tensioning means 40 that pulls the driving wire 20 that passes through the moving pulley 10. In the rotation mechanism 100b, as the bending of the robot finger 100 progresses, the direction of the tensile forces F1 and F2 acting on the movable pulley 10 from the driving wire 20 changes to the rotation axis Ra at the positions P1 and P2 of the movable pulley 10. It is configured to approach the directions of tangents L1 and L2 to the circumference C as the center (FIG. 3(b)). In other words, in the rotation mechanism 100b, as the bending of the robot finger 100 progresses, the direction of the tensile forces F1 and F2 acting on the movable pulley 10 from the drive wire 20 changes from the direction of the forces F1a and F2a that rotate the frame member 110. The direction is getting closer. Note that the rotation axis Ra here is the central axis of the shaft member 50.

For example, when the robot hand 1 performs an action of bending the robot finger 100, that is, when the posture of the frame member 110 changes from the extended state shown in FIG. 1(b) to the bent state shown in FIG. 3(a), The movable pulley 10 moves from the extended position P1 to the bent position P2, as shown in FIG. 3(b). In addition, in FIG. 1(b), FIG. 3(a), and FIG. 3(b), the positions P1 and P2 of the movable pulley 10 are the rotation axis of the movable pulley 10 (specifically, the central axis of the disc of the movable pulley 10). ) position.

When the movable pulley 10 is in the extended position P1 (FIG. 1(b)), as shown in FIG. 3(b), the direction of the tangent L1 of the circumference C centered on the rotation axis Ra at this extended position P1 and the direction of the tensile force F1 acting on the movable pulley 10 from the drive wire 20 form an angle α1.

Furthermore, when the movable pulley 10 moves from the extended position P1 (FIG. 1(b)) to the bent position P2 (FIG. 3(a)), the rotation axis at the bent position P2 is The direction of the tangent L2 of the circumference C centered on Ra and the direction of the tensile force F2 acting on the movable pulley 10 from the drive wire 20 form an angle α2 (α2<α1).

Therefore, when the frame member 110 changes from the extended state (FIG. 1(b)) to the bent state (FIG. 3(a)), the movable pulley 10 moves from the extended position P1 to the bent position P2. The directions of the tensile forces F1 and F2 acting on the movable pulley 10 from the movable pulley 10 approach the tangents L1 and L2 of the circumference C centered on the rotation axis Ra at the position of the movable pulley 10. That is, depending on the amount of tension that the tensioning means 40 pulls on the driving wire 20, the directions of the forces F1 and F2 acting on the moving pulley 10 approach the direction of the forces F1a and F2a that rotate the frame member 110.

As a result, even if the magnitudes of the forces F1 and F2 with which the tensioning means 40 pulls the drive wire 20 are the same, the force that rotates the frame member 110 around its rotation axis Ra (that is, the rotational moment (M1, M2) is larger when the movable pulley 10 is in the bent position P2 (M2) than when the movable pulley 10 is in the extended position P1 (M1).In other words, in this robot finger 100, the frame member 110 is The more the frame member 110 is bent, the more the rotational force (power for gripping an object) used to rotate the frame member 110 by the movable pulley 10 increases, even if the tensile force applied by the tensioning means 40 to pull the drive wire 20 is constant.

Here, the rotation mechanism 100b is a mechanism that drives the third joint (MP joint) of the robot finger 100, and specifically, a mechanism that rotates the third frame piece 110c with respect to the base 100a. In the rotation mechanism 100b that drives the third joint, the third frame piece 110c is biased by a biasing means (not shown) against the base 100a so that the robot finger 100 always returns to the extended position shown in FIG. 1(b). has been done. However, instead of such a biasing means, the rotation mechanism 100b that drives the third joint may have a return rotation mechanism that returns the robot finger 100 to the extended position shown in FIG. 1(b). . This return rotation mechanism may have the same configuration as the rotation mechanism 100b that drives the third joint described above, or may have a different configuration.

Although the mechanism for driving the second joint (PIP joint) and the first joint (DIP joint) is not specifically shown here, the mechanism for driving the second frame piece 110b with respect to the third frame piece 110c is not specifically shown. The two-joint rotation mechanism and the first joint rotation mechanism that drives the first frame piece 110a with respect to the second frame piece 110b may have the same configuration as the third joint rotation mechanism 100b described above. good. In that case, in the rotation mechanism of the second joint, the third frame piece plays the role of the base in the drive mechanism of the third joint, and in the rotation mechanism of the first joint, the third frame piece plays the role of the base in the drive mechanism of the third joint. This is what the second frame piece will do. In addition, in the rotation mechanism of the second joint, the frame piece connecting pin 113b of the second frame piece 110b plays the role of the shaft member in the drive mechanism of the third joint, and in the rotation mechanism of the first joint, the role of the shaft member in the drive mechanism of the third joint is played by the frame piece connecting pin 113b. The frame piece connecting pin 112b of the second frame piece 110b plays the role of a shaft member in the drive mechanism.

Alternatively, the rotation mechanism of the second joint and the rotation mechanism of the first joint may have different configurations from the rotation mechanism 100b of the third joint.

In addition, the mechanism that drives both the second joint and the first joint is an urging force that always urges the movement of each joint so that the robot finger 100 returns to the posture of the extended position shown in FIG. 1(b). Alternatively, instead of such biasing means, the mechanism for driving at least one of the second joint and the first joint may have a return rotation that returns the robot finger 100 to the extended position. It may have a moving means. Further, this return rotation mechanism may have the same configuration as the rotation mechanism 100b that drives the third joint described above, or may have a different configuration.

The detailed configuration of the rotation mechanism 100b will be specifically explained below.

As described above, the rotation mechanism 100b includes the shaft member 50 that rotatably supports the third frame piece 110c with respect to the base 100a, the movable pulley 10 attached to the third frame piece 110c, and the movable pulley 10. It includes a driving wire 20 suspended, a fixed pulley 30 attached to the base plate 101, and a tensioning means 40 for pulling the other end of the driving wire 20. Here, the movable pulley 10 is attached to the third frame piece 110c so as to rotate together with the third frame piece 110c around the rotation axis Ra of the frame member 110. Further, the tensioning means 40 may be a pneumatic or hydraulic type (hydraulic type, hydraulic type, etc.) cylinder that moves the rod connected to the other end of the drive wire 20 in and out, or the tensioning means 40 may be a pneumatic or hydraulic type (hydraulic type, hydraulic type, etc.) cylinder that moves the rod connected to the other end of the drive wire 20, or the tensioning means 40 may be a pneumatic type or hydraulic type (hydraulic type, hydraulic type, etc.) cylinder that moves the rod connected to the other end of the drive wire 20. It may also be an actuator that drives it so that it can move in and out.

FIG. 4 is a schematic diagram showing the layout of the driving wire 20 used in the robot finger 100 shown in FIG. 1(a), and FIG. 4(a) shows the robot in the extended state shown in FIG. 1(b). The layout of the driving wire 20 in the finger 100 is shown, and FIG. 4(b) shows the layout of the driving wire 20 in the robot finger 100 in the bent state shown in FIG. 3(a).

Here, the shaft member 50 is located between the movable pulley 10 and one end 20a (that is, the tensioning means 40) of the drive wire 20, and the fixed pulley 30 is located between the movable pulley 10 and the other end 20b of the drive wire 20. It is located between. Further, the first portion W1 of the driving wire 20 located between the one end 20a and the movable pulley 10 is bent by contacting the shaft member 50. This reduces the dimension of the first portion W1 in the direction connecting the movable pulley 10 and one end 20a of the drive wire 20.

Further, the second portion W2 of the drive wire 20 located between the other end 20b and the movable pulley 10 is in contact with the fixed pulley 30, so that the second portion W2 is in substantially the same direction as the first portion W1 and substantially in the same direction as the first portion W1. bent to the same degree. This reduces the dimension of the second portion W2 in the direction connecting the movable pulley 10 and the other end 20b of the drive wire 20, and also allows the drive wire 20 that is folded back by the movable pulley 10 to face each other. The width of the placement area is narrowed.

The rotation mechanism 100b having such a configuration rotates the frame member 110 around the rotation axis Ra by using the tensioning means 40 to pull the driving wire 20 that is hung on the movable pulley 10 attached to the third frame piece 110c. As the bending of the robot finger 100 progresses, the direction of the tensile forces F1 and F2 acting on the movable pulley 10 from the drive wire 20 changes to a direction on the circumference C centered on the rotation axis Ra. It is configured to approach the directions of tangents L1 and L2 at positions P1 and P2 of the movable pulley 10.

As a result, in this rotation mechanism 100b, the tensile forces F1 and F2 that act on the movable pulley 10 from the drive wire 20 when the tension means 40 pulls the drive wire 20 are However, the more the frame member 110 rotates from the extended position toward the bent position, the more the direction of the tensile forces F1 and F2 changes. It becomes possible to approach the force directions F1a and F2a (see FIG. 3(b)) and increase the rotational force.

Also, in both the extended state and the bent state of the robot finger 100 (FIGS. 4(a) and 4(b)), one end of the first portion W1 of the drive wire 20 is connected to the shaft member 50. The portion W1a between the fixed pulley 30 and the other end 20b of the second portion W2 of the driving wire 20 is generally parallel to the portion W2a between the fixed pulley 30 and the other end 20b. This narrows the width of the driving wire arrangement area.

Furthermore, one end 20a of the drive wire 20 is fixed to the base 100a by a fixing part 103, and the other end 20b of the drive wire 20 is connected to the tensioning means 40. As a result, one tensioning means 40 can pull the movable pulley 10 with a force of about 1/2 of the load applied to the movable pulley 10.

Note that the robot finger 100 described here corresponds to the index finger, but the robot fingers 100 corresponding to the four fingers other than the index finger also have the same configuration as the robot finger 100 corresponding to the index finger described above. Needless to say, it is.

The robot finger 80 corresponding to the thumb will be described below.

[Thumb robot finger 80 corresponding to the thumb]
This thumb robot finger 80 has a frame member 81 corresponding to the thumb, and this deflection member 81 is similar to the robot finger 100 corresponding to the fingers other than the thumb as shown in FIG. It has three frame pieces.

In other words, the frame member 81 corresponding to the thumb includes a first frame piece 81a corresponding to the tip of the finger, a third frame piece 81c corresponding to the root of the finger, and the tip and root of the finger. It has a second frame piece 81b corresponding to the intermediate part between the two parts.

That is, in the thumb robot finger 80, the first frame piece 81a corresponds to the part beyond the first joint (IP joint) of the human thumb, and the second frame piece 81b corresponds to the part beyond the first joint (IP joint) of the human thumb. The third frame piece 81c corresponds to the part between the second joint and the third joint (CM joint) of the human thumb. .

The thumb robot finger 80 also has a base 80a that corresponds to the base 100a in the robot finger 100 corresponding to fingers other than the thumb, and has a rotation mechanism 100b that corresponds to the rotation mechanism 100b in the robot finger 100 corresponding to fingers other than the thumb. It has a mechanism 80b. That is, in this robot hand 1, the base 80a of the thumb robot finger 80 and the base 100a of the robot finger 100 corresponding to fingers other than the thumb are the same; It is shared with the robot finger 100 corresponding to the finger. Further, in FIG. 1A, the rotation mechanism 80b of the thumb robot finger 80, which corresponds to the rotation mechanism 100b of the robot finger 100 corresponding to a finger other than the thumb, is the third joint (CM joint), that is, the rotation mechanism 80b of the robot finger 100 corresponding to a finger other than the thumb. Although the frame piece 81c of No. 3 is shown as rotating, it may be one that rotates the first joint (IP joint) or one that drives the second joint (MP joint).

Next, the operation of the robot finger 100 of the first embodiment will be explained.

FIG. 5 is a plan view showing a mechanism in which the rotational force of the robot finger 100 shown in FIG. 1 increases as the robot finger 100 bends. FIG. The direction of the force F1 is shown, and FIG. 5(b) shows the direction of the tensile force F2 applied to the movable pulley 10 when the robot finger 100 is bent.

In the extended state of the robot finger 100 shown in FIG. 1(b), the layout of the driving wire 20 is the extended position layout shown in FIG. 5(a).

That is, the movable pulley 10 is located at a point P1 on a circumference C centered on the rotation axis Ra and whose radius is the distance between the rotation axis Ra and the center of the movable pulley 10, and the center of the fixed pulley 30 is is approximately located at one point P0 on this circumference. The rotation center Ra of the movable pulley 10 (rotation axis of the frame member 110), the center P1 of the movable pulley 10, and the center P0 of the fixed pulley 30 are two points with the rotation center Ra as the apex. They form an equilateral triangle.

The other end of the drive wire 20 extends from the movable pulley 10 via the fixed pulley 30 to the tensioning means 40, and one end of the drive wire 20 is generally along the other end. The tensile force F1 acting on the movable pulley 10 from the drive wire 20 is approximately parallel to the portion of the drive wire 20 that goes from the movable pulley 10 to the fixed pulley 30.

As a result, a large angle α1 (see FIGS. 5(a) and 3(b)) is formed with respect to the direction of the tangent L1 at the position P1 of the movable pulley 10.

When the tensioning means 40 pulls the drive wire 20 with the robot finger 100 in this extended state, and the posture of the robot finger 100 gradually changes from the extended state to the bent state, the movable pulley 10 approaches the fixed pulley 30. Therefore, the tensile force F2 acting on the movable pulley 10 is a force in a direction away from the radial direction of the circumference C around which the movable pulley 10 rotates (direction from the center P2 of the movable pulley 10 toward its center of rotation). .

As a result, a smaller angle α2 (see FIGS. 5(b) and 3(b)) is formed with respect to the direction of the tangent L2 at the position P2 of the movable pulley 10.

In this way, in the robot finger 100, when the posture of the robot finger 100 changes from the extended state to the bent state, the tensile force applied to the movable pulley 10 by the driving wire 20 is applied to the circumference C along which the movable pulley 10 moves. The direction of the tangent L2 at the position P2 of the movable pulley 10 (that is, the direction of the force that rotates the frame member 110) approaches. Therefore, with this robot finger 100, the gripping force of the robot finger 100 can be increased as the gripping motion of the robot finger 100 progresses without increasing the tensile force of the drive wire 20.

Two conventional methods for driving a robot finger will be described below as Comparative Examples 1 and 2 of Embodiment 1 in comparison with Embodiment 1.

(Comparative example 1)
One conventional method is to attach a pair of drive wires to the ends of a fixed pulley attached to a frame member (component corresponding to the finger part) constituting the robot finger, and connect one drive wire to the end of the In this method, the frame member is bent by pulling it, and the frame member is stretched by pulling the other driving wire by rotating the motor in the opposite direction. In this method, the rotation mechanism of the frame member becomes simple.

However, with such conventional wire drives, if a fixed pulley attached to a frame member is driven by an individual motor, the diameter of the fixed pulley must be increased in order to generate the large rotational force required for the frame member. This makes downsizing difficult.

(Comparative example 2)
Another conventional method is interference drive in which multiple motors jointly rotate the rotation axis of a joint that requires a large driving force among the multiple joints of a robot finger by connecting multiple drive wires. This is a method that uses With this method, it is possible to keep the output of each motor low even when driving a joint that requires a large driving force.

However, using interference drive using a plurality of drive wires increases the number of drive wires, and the arrangement of the drive wires, that is, the layout of the drive wires in a narrow space becomes complicated.

(Embodiment 1 of the present invention)
In contrast, in the first embodiment, the frame member 110 that constitutes the finger portion of the robot hand 1 is rotated using the movable pulley 10 fixed to the frame member 110. The rotational force of the frame member 110 can be doubled without changing the force that drives the movable pulley 10, and the movable pulley 10, the shaft member 50 that rotatably supports the frame member 110, and the movable pulley 10 can be doubled. Depending on the positional relationship with the tensioning means 40 that pulls the passing drive wire 20, it is possible to increase the rotational force of the frame member 110 as the frame member 110 bends and stretches.

As a result, in the robot finger 100 of the first embodiment, compared to the conventional method of rotating a pulley by fixing a wire to the end of the pulley, or the method of rotating the pulley using interference drive, the pulley has a large size. The frame member 110 can be rotated with a large rotational force without complicating the arrangement of drive wires or driving wires.

As mentioned above, although the present invention has been illustrated using the preferred embodiment of the present invention, the present invention should not be interpreted as being limited to this embodiment. It is understood that the invention is to be construed in scope only by the claims. It will be understood that those skilled in the art will be able to implement the present invention to an equivalent extent based on the description of the present invention and common general technical knowledge from the description of the specific preferred embodiments of the present invention. It is understood that the documents cited herein are to be incorporated by reference into this specification to the same extent as if the documents themselves were specifically set forth herein.

The present invention achieves miniaturization and high gripping force with a simple structure compared to the conventional method of fixing a wire to the end of a pulley and rotating the pulley, or using interference drive to rotate the pulley. The present invention is useful in that it is possible to obtain a robot finger and a robot hand including such a robot finger.

1 Robot hand 10 Moving pulley 20 Driving wire 30 Fixed pulley 40 Tension means 50 Shaft member 80 Thumb robot finger 80a, 100a Base 80b, 100b Rotating mechanism 81, 110 Frame member 81a, 110a First frame piece 81b, 110b Second Frame piece 100 Robot finger (compatible with fingers other than the thumb)
101 Base plate 102 Base cover 103 Fixed part 104, 114b, 115b Locking clip 110c Third frame piece 111a, 111b, 111c Frame piece main body 112a, 112c Frame piece connecting hole 112b, 113b Frame piece connecting pin 113a Tip grip part 113c Base Connection hole 114a Fixing screw C Circumference F1, F2 Tensile force F1a, F2a Rotating force of frame member L1, L2 Tangent line P1, P2 Position Ra Rotating axis

Claims (6)

A robot finger used for a robot hand,
a frame member that constitutes a finger portion of the robot hand;
a base including a shaft member that rotatably supports the frame member;
a movable pulley fixed to the frame member;
a driving wire for driving the frame member;
and a pulling means for pulling the drive wire,
One end of the driving wire is fixed to the base, and the other end of the driving wire is connected to the tensioning means via the movable pulley,
A robot finger, wherein at least the movable pulley, the drive wire, the shaft member, and the tensioning means constitute a rotation mechanism for rotating the frame member. In the rotation mechanism, the movable pulley rotates around the shaft member due to the force of the tensioning means pulling the other end of the drive wire, and the frame member is accordingly moved in a direction in which the finger portions are bent. The robot finger of claim 1, wherein the robot finger is configured to rotate. The rotation mechanism progresses the bending of the fingers in response to the force with which the tension means pulls the other end of the drive wire, and the rotation mechanism advances the bending of the finger portions in response to the force with which the tension means pulls the other end of the drive wire. The robot finger according to claim 2, wherein the direction of the applied force approaches the direction of the force that rotates the frame member. The movable pulley moves on a circumference centered on the shaft member and whose radius is the distance between the shaft member and the movable pulley,
The robot finger according to claim 3, wherein the shaft member is arranged between the movable pulley and the tensioning means. The robot finger according to claim 4, wherein a fixed pulley is attached to the base so as to be located between the movable pulley and the other end of the drive wire. A robot hand comprising five robot fingers according to claim 1.

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