WO2022186033A1

WO2022186033A1 - Robot hand provided with articulated finger

Info

Publication number: WO2022186033A1
Application number: PCT/JP2022/007540
Authority: WO
Inventors: 一晶田中
Original assignee: 国立大学法人京都工芸繊維大学
Priority date: 2021-03-04
Filing date: 2022-02-24
Publication date: 2022-09-09
Also published as: JPWO2022186033A1

Abstract

An articulated finger F of a robot hand H is provided with a first finger part 11, a second finger part 12, and a third finger part 13. The second finger part 12 is connected to the first finger part 11 so as to be able to rotate about a first rotation axis, a bendable/extendable first joint 21 is formed, the third finger part 13 aid connected to the second finger part so as to be able to rotate about a second rotation axis, and a bendable/extendable second joint 22 is formed. A bending force action part W2 that causes a bending force to act on the first joint 21 and the second joint 22, a first elastic body 5 provided in the vicinity of the first joint 21 that generates an extension force that resists the bending force acting on the first joint 21, and a second elastic body 62 provided in the vicinity of the second joint 22 that generates an extension force that resists the bending force acting on the second joint are provided, and the extension force of the second elastic body 62 is smaller than the extension force of the first elastic body 61.

Description

Robot hand with articulated fingers

The present invention relates to a robot hand, particularly a robot hand with articulated fingers.

Equipment called manipulators and robot hands with articulated fingers (hereinafter collectively referred to as robot hands) have been developed and used at manufacturing sites. In particular, robot hands imitating human hands have been proposed for use in artificial hands and, in recent years, as remote communication tools.

In general, such a robot hand assumes a state in which the joints are extended as an initial state, and each joint is displaced to a bent state by a driving force such as an actuator. Various methods for transmitting the driving force to each joint have been proposed, including a method in which each joint is provided with a pulley and a wire wound around the pulley to transmit the driving force (for example, Patent Document 1); One that transmits individual driving force to joints (for example, Patent Document 2), one that transmits driving force by a wire passed through each finger member (for example, Patent Document 3), and one that transmits driving force by a link mechanism. There is a device for transmission (Patent Document 4) and the like.

JP-A-7-096485 JP 2012-016784 A JP 2019-076786 A JP 2019-093457 A

According to the above-mentioned robot hand, since the driving force is transmitted to each finger member and joint, and the joint is displaced into a bent state, it is possible to clamp an object in the manufacturing process. However, depending on the purpose of use, such as when using a robot hand as a prosthetic hand or as a communication tool, it is necessary to freely control the order of flexion of the finger joints, or to control the movements so that they resemble human finger joints. may be desired.

In order to solve such problems, the robot hand of Patent Document 1 is provided with a clutch/brake for each pulley, and controls the bending of each joint by controlling the opening and closing of each clutch/brake. . In addition, the robot hand of Patent Document 2 is individually provided with motors that supply driving force to each joint, and these are individually controlled. However, these robot hands have complicated controls and structures, and are difficult to miniaturize.

On the other hand, in the robot hand of Patent Document 3, the magnitude of the rotational moment acting on each joint is made different. Due to such a configuration, when the wire rod is pulled and a force acts on the joints in the bending direction, the joints are displaced into the bent state in descending order of the rotational moment. As a result, the plurality of joints can be displaced to the bent state in the specified order.

However, depending on the direction of the palm of the robot hand, the magnitude of the rotational moment acting on each joint differs from the theoretical value, so there is a possibility that multiple joints cannot be bent in the desired order.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a robot hand having a multi-joint finger that can bend or extend a plurality of finger joints in a prescribed order with a simple configuration. is to provide

In order to solve the above-described problems, in one preferred embodiment of the robot hand having an articulated finger according to the present invention, the articulated finger includes at least a first finger, a second finger, and a third finger, wherein the second finger is connected to the vicinity of the fingertip side end of the first finger so as to be rotatable around a first rotation axis, and is a first joint capable of bending/extending. and the third finger is rotatably connected to the vicinity of the fingertip side end of the second finger about a second rotation axis to form a second joint capable of bending/extending, a bending force acting portion that applies a bending force to a first joint and the second joint; and a first elastic member that is provided in the vicinity of the first joint and produces an extension force that resists the bending force acting on the first joint. and a second elastic body provided in the vicinity of the second joint and generating an extension force that resists the bending force acting on the second joint, wherein the extension force of the second elastic body is It is smaller than the extension force of the first elastic body.

In this configuration, since the extension force of the second elastic body placed near the second joint is smaller than the extension force of the first elastic body placed near the first joint, the flexion force acting portion is applied to each joint. When a bending force is applied by pressing the second joint, the second joint bends more easily than the first joint. Therefore, by setting the joint to be bent first as the second joint and the joint to be bent later as the first joint, the joints can be bent in a prescribed order. Even if there are three or more joints, the joints can be bent in a prescribed order by similarly setting the extension force of the elastic body.

In one preferred embodiment of the robot hand according to the present invention, the first elastic body and the second elastic body are springs, and the spring constant of the second elastic body is greater than the spring constant of the first elastic body. is also small.

In this configuration, since the first elastic body and the second elastic body are springs such as coil springs and leaf springs, the configuration can be simplified. In this case, the magnitude of the extension force can be set as the spring constant of the elastic body (spring).

In one preferred embodiment of the robot hand according to the present invention, the first elastic body is fixed to the first finger portion and the second finger portion so as to straddle the first joint, and A single coil spring that is fixed to the second finger and the third finger so as to straddle the second joint and constitutes the second elastic body, wherein the number of turns of the second elastic body is the first. Less than the number of turns of the elastic body.

With this configuration, a part of the single coil spring can be used as the first elastic body and the second elastic body, so the configuration can be simplified. In this case, the spring constant of the elastic body (spring) can be set as the number of turns.

In one preferred embodiment of the robot hand according to the present invention, the first elastic body and the second elastic body are compression coil springs provided on the palm side, and the bending force application portion is a wire, or The first elastic body and the second elastic body are extension coil springs provided on the back side of the hand, and have a wire for applying an extension force to the first joint and the second joint, and the wire is inserted through the coil spring. ing.

In this configuration, a wire is provided that applies a bending force or an extension force to the joints of the multi-articulated finger. Such a wire must be attached so as not to get caught on other members or surrounding objects during use. In this configuration, since the wire is inserted through the coil spring as the elastic body, it is possible to prevent the wire from being caught without using other members, and the configuration can be simplified.

In one preferred embodiment of the robot hand according to the present invention, a covering elastic body is provided to cover the articulated finger, and the first elastic body and the second elastic body respectively correspond to the first joint and the second joint. The elastic force of the second elastic body is smaller than the elastic force of the first elastic body, which is part of the covering elastic body located nearby.

Depending on the purpose of use, the robot hand is covered with an elastic coating such as silicone rubber in order to make the tactile feel of the robot hand closer to that of a human hand. In this configuration, the covering elastic bodies are the first elastic body and the second elastic body, and the configuration is simple. In this case, the extension force of the first elastic body and the second elastic body can be changed by changing the elastic force of the portion of the covering elastic body located near the first joint and the second joint. The elastic force can be changed by changing the hardness or thickness of that portion of the covering elastic body.

It is a perspective view of a robot hand. FIG. 4 is an exploded perspective view of the forefinger of the robot hand in an extended state; (a) Perspective view of the index finger of the robot hand, (b) III-III sectional view of the index finger of the robot hand. FIG. 4 is a side cross-sectional view showing a bending motion of the index finger; 2 is a side cross-sectional view of the index finger of the robot hand in Example 1. FIG. FIG. 11 is a side cross-sectional view of the index finger of the robot hand in Example 2; FIG. 12 is a side cross-sectional view of the index finger of the robot hand in Example 3; FIG. 12 is a side cross-sectional view of the index finger of the robot hand in Example 4; It is an enlarged view near the bent joint.

An embodiment of a robot hand according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a robot hand having articulated fingers (hereinafter abbreviated as robot hand H) according to the present embodiment. As shown in the figure, the robot hand H imitates a human hand and has five articulated fingers F1, F2, F3, F4, and F5 corresponding to the thumb, index finger, middle finger, ring finger, and little finger. . In the following description, when there is no need to distinguish between them, they are referred to as finger F. On the other hand, when distinguishing, it may be described as a thumb F1 or the like.

As described above, the robot hand H in this embodiment imitates a human right hand, and thus has five fingers F. However, the number of fingers F can be changed as appropriate depending on the application. Also, the number of joints can be changed as appropriate.

Fig. 1 shows the robot hand H with its palm facing upward. Fingers other than the thumb F1 have a metacarpal bone 11, a proximal phalanx 12, a middle phalanx 13 and a distal phalanx 14. As shown in FIG. The metacarpal bone 11 and the proximal phalanx 12 are arranged adjacent to each other in the longitudinal direction, and are rotatably connected at the adjacent portions. This connecting portion is the MP joint 21 . The proximal phalanx 12 and the middle phalanx 13 are similarly connected to form a PIP joint 22 , and the middle phalanx 13 and the distal phalanx 14 are also connected to form a DIP joint 23 . The thumb F1 has substantially the same structure, but does not include the middle phalanx 13, and the proximal phalanx 12 and the distal phalanx 14 are connected to form an IP joint 24. As shown in FIG. By making the joints of each finger F rotatable in this manner, the finger F can be flexed/extended.

The metacarpal bones 11 of the index finger F2, middle finger F3, ring finger F4, and little finger F5 are inserted through and fixed to the base member 3 located near the wrist. Specifically, in plan view, the adjacent metacarpal bones 11 are not parallel to each other, but are fixed at an angle that opens the fingertips. The metacarpal bone 11 of the thumb F1 is fixed to the end of the base member 3 on the index finger F2 side via the thumb support member 31 .

Next, the structure of the finger F in this embodiment will be described using FIG. FIG. 2 is an exploded perspective view of the index finger F2 in an extended state. As described above, the structure of each finger F is basically the same although there are differences in size and the thumb F1 described above. Therefore, the structure of the index finger F2 will be described here.

The index finger F2 has a metacarpal bone 11, a proximal phalanx 12, a middle phalanx 13, and a distal phalanx 14, like a human finger. The metacarpal bone 11 is composed of an elongated substantially rectangular metacarpal plate 11a and pressing members 11c arranged on both side surfaces of the metacarpal plate 11a on the wrist side. The proximal phalanx 12 includes an elongated, substantially rectangular plate-shaped proximal phalanx inner plate 12a, pressing members 12c arranged on both side surfaces of the proximal phalanx inner plate 12a, and outer side surfaces of the respective pressing members 12c. and a plate-like proximal phalanx outer plate 12b. Similarly, the middle phalanx 13 has an elongated substantially rectangular middle phalanx inner plate 13a, pressing members 13c arranged on both side surfaces of the middle phalanx inner plate 13a, and outer side surfaces of each pressing member 13c. and a plate-shaped middle phalanx outer plate 13b to be placed. The distal phalanx 14 is composed of a distal phalanx inner plate 14a and plate-like distal phalanx outer plates 14b arranged on both sides of the distal phalanx inner plate 14a.

As shown in FIG. 1 , the wrist-side end of the metacarpal plate 11 a is inserted through the insertion hole 3 a of the base member 3 . The fixing member 4 is screwed to the metacarpal plate 11a in the inserted state from the front and rear in the insertion direction and the thickness direction of the metacarpal plate 11a. Thereby, the first finger plate 11 a is fixed to the base member 3 . 1 and 2, screws are omitted.

A proximal phalanx inner plate 12a is arranged at the end of the metacarpal plate 11a on the fingertip side, followed by a middle phalanx inner plate 13a and a distal phalanx inner plate 14a in order so that their axes are aligned. A pair of pressing

members

11c, 12c, and 13c are arranged on both sides of the metacarpal plate 11a, the proximal phalanx inner plate 12a, and the middle phalanx inner plate 13a. The length of the pressing member 11c is about the same as that of the fixing member 4, and is fixed by being sandwiched between the fixing members 4 on the fingertip side of the metacarpal plate 11a. The length of the pressing member 12c is slightly shorter than the length of the proximal phalanx inner plate 12a, and the pressing member 12c is arranged so that the wrist-side end of the pressing member 12c and the wrist-side end of the proximal phalanx inner plate 12a coincide. . Similarly, the length of the pressing member 13c is slightly shorter than the length of the middle phalanx inner plate 13a, and the wrist-side end of the pressing member 13c and the wrist-side end of the middle phalanx inner plate 13a are aligned. are placed.

A proximal phalanx outer plate 12b is arranged on the outer surface of each pressing member 12c, and the proximal phalanx outer plate 12b is screwed to the proximal phalanx inner plate 12a together with the pressing member 12c. A support shaft (not shown) is inserted through the shaft hole 12bh closest to the wrist of the outer plate 12b of the proximal phalanx, and the support shaft is inserted into the hole 11ah closest to the fingertip of the metacarpal plate 11a. (not shown). Thereby, the proximal phalanx 12 is connected to the metacarpal 11 so as to be rotatable about the rotation axis A1. Also, this rotatable connection forms an MP joint 21 capable of flexion/extension.

Similarly, the middle phalanx 13 also has a middle phalanx outer plate 13b arranged on the outer surface of each pressing member 13c. screwed. A support shaft (not shown) is inserted through the shaft hole 13bh closest to the wrist of the outer plate 13b of the middle phalanx. not shown). Thereby, the middle phalanx 13 is connected to the proximal phalanx 12 so as to be rotatable about the rotation axis A2. This pivotable connection also forms a PIP joint 22 capable of flexion/extension.

A support shaft (not shown) is inserted through the shaft hole 14bh closest to the wrist of the outer plate 14b of the distal phalanx. (not shown). Thereby, the distal phalanx 14 is connected to the middle phalanx 13 so as to be rotatable about the rotation axis A3. This pivotable connection forms a DIP joint 23 capable of flexion/extension movement.

FIG. 3(a) is a perspective view of the index finger F2, and FIG. 3(b) is a cross-sectional view taken along line III-III in FIG. As shown in the figure, the pressing member 12 c has a substantially U-shaped cross section and includes a side plate 51 , an upper plate 52 and a lower plate 53 . A gap is formed between the upper inner surface 52a of the superior plate 52 and the upper surface of the proximal phalanx inner plate 12a to form a passage P. As shown in FIG. A gap (path P) is similarly formed between the lower inner surface 53a of the lower plate 53 and the lower surface of the proximal phalanx inner plate 12a. Similarly, the middle phalanx 13 also has a passage P formed vertically.

Although not shown in FIGS. 1 to 3, the finger F of the robot hand H according to the present invention has elastic bodies that apply different extension forces to each joint position. Therefore, when a bending force acts on each joint, the magnitude of bending or stretching of each joint differs due to the difference in the stretching force, and the order of bending or stretching differs.

FIGS. 4(a) to 4(d) are side cross-sectional views showing the bending motion of the index finger F2 in chronological order. The cross-sectional position is the front side of the metacarpal plate 11a in the drawing, which is indicated by IV-IV in FIG. 3(a). Side cross-sectional views in the following examples are also at the same cross-sectional position. Note that the elastic body is not shown in FIG. 4 because it will be described in the following examples.

In this embodiment, wires W1 and W2 are provided on the back side of the hand (upper side in the figure) and the palm side (lower side in the figure). The wires W1 and W2 are passed through the passage P shown in FIG. 3 from the wrist side toward the fingertips, one end of which is fixed to the distal phalanx 14, and the other end of which is connected to an actuator or the like (not shown). When a tensile force (rightward force in the figure) acts on the wire W1 by an actuator or the like, the finger F tries to extend. On the other hand, when a tensile force (rightward force in the figure) acts on the wire rod W2 (an example of the bending force applying portion in the present invention), the finger F tends to bend toward the palm side. When bending the finger F, it is necessary to loosen or release the tensile force on the wire rod W1. As described above, since the wires W1 and W2 are inserted through the passage P, even if they become loose, they are less likely to get caught on other members or surrounding objects. As the wires W1 and W2, wires, fishing lines, and the like can be used as long as they can transmit the tensile force from the actuator or the like.

As described above, when the wire rod W1 is loosened and a tensile force is applied to the wire rod W2, the finger F is apparently bent in the order of the DIP joint 23, the PIP joint 22, and the MP joint 21, as shown in this figure. Of course, the bending order of the joints can be changed as appropriate, and it is also possible to bend the MP joint 21, the PIP joint 22, and the DIP joint 23 in this order.

FIG. 5(a) is a side sectional view of the index finger F2 in this embodiment. In side sectional views of this embodiment and the following, the palm side is downward. As shown in the figure, springs 61, 62 and 63 (examples of the first and second elastic bodies in the present invention) are provided on the palm sides of the MP joint 21, PIP joint 22 and DIP joint 23, respectively. Specifically, the spring 61 is a compression coil spring, and is arranged so as to be sandwiched between the end face of the holding member 11c on the fingertip side and the end face of the holding member 12c on the wrist side. exerting force. The spring 62 is also a compression coil spring, and is arranged so as to be sandwiched between the end face of the pressing member 12c on the fingertip side and the end face of the pressing member 13c on the wrist side. there is The spring 63 is also a compression coil spring, and is arranged so as to be sandwiched between the fingertip-side end surface of the pressing member 13c and the wrist-side end surface of the distal phalanx inner plate 14a, and biases the DIP joint 23 in the extension direction. is acting.

The wire rod W2 is inserted through the passage P and the

springs

61, 62, 63. Therefore, the wire rod W2 is hardly exposed to the outside and is less likely to get caught on other members or the like.

Assuming that the spring constants of the

springs

61, 62, and 63 are k1, k2, and k3, respectively, k1>k2>k3. Therefore, when a tensile force is applied to the wire rod W2, the spring 63 is most likely to contract and the spring 61 is most difficult to contract with the same force. Thereby, the DIP joint 23, the PIP joint 22, and the MP joint 21 can be bent in this order.

Although compression coil springs are used as the

springs

61, 62, and 63, leaf springs may be used.

As a modification of this embodiment, the

springs

61, 62, 63 can be a single spring 6, as shown in FIG. 5(b). In this modified example, the spring 6 is provided from the end face of the pressing member 11c on the fingertip side to the end face of the distal phalanx inner plate 14a on the wrist side. The spring 6 is inserted through the passage P at the proximal phalanx 12 and middle phalanx 13 portions.

In this modified example, the springs 6 are fixed at both ends of each joint, and springs 61, 62, and 63 are formed between the fixed portions. That is, the portion from the fixed position on the metacarpal bone 11 to the fixed position on the proximal phalanx 12 is the spring 61, the portion from the fixed position on the proximal phalanx 12 to the fixed position on the middle phalanx 13 is the spring 62, The spring 63 corresponds to the fixed position at the middle phalanx 13 to the fixed position at the distal phalanx 14 . At this time, the number of turns of the

springs

61, 62, and 63 are varied so that the spring constants of the

springs

61, 62, and 63 are fixed as described above. A change in the number of turns can be realized by changing the fixing interval or extending the fixed portion.

In this way, by arranging the

springs

61, 62, 63 with different spring constants in the joint portion on the palm side, it is possible to bend the joints in order from the joints where the springs with the smaller spring constants are arranged. Moreover, even if a very large tensile force acts on the wire rod W2, the

springs

61, 62, and 63 prevent bending beyond a certain level, so that an accident such as crushing the object can be prevented. can.

Also, when the wire rod W2 is loosened while each joint is bent, the

springs

61, 62, and 63 are elastically restored, and each joint is displaced to the extended state. At this time, the order of the joints to be extended is determined by the difference in the magnitude of the spring constant. Specifically, the MP joint 21, the PIP joint 22, and the DIP joint 23, to which the spring 61 having the largest spring constant is arranged, are extended in this order. That is, not only the flexion order but also the extension order can be controlled by the magnitude of the spring constant of the elastic body arranged at each joint.

When the metacarpal bone 11 is viewed as the first finger in the present invention, the proximal phalanx 12 is the second finger, the middle phalanx 13 is the third finger, the MP joint 21 is the first joint, and the PIP joint 22 corresponds to the second joint, the rotation axis A1 corresponds to the first rotation axis, the rotation axis A2 corresponds to the second rotation axis, the spring 61 corresponds to the first elastic body, and the spring 62 corresponds to the second elastic body. The proximal phalanx 12 can also be viewed as the first finger in the present invention, in which case the middle phalanx 13 is the second finger, the distal phalanx 14 is the third finger, and the PIP joint 21 is the first finger. The DIP joint 23 corresponds to the second joint, the rotation axis A2 corresponds to the first rotation axis, the rotation axis A3 corresponds to the second rotation axis, the spring 62 corresponds to the first elastic body, and the spring 63 corresponds to the second elastic body. The same applies to the following examples.

FIG. 6(a) is a side sectional view of the index finger F2 in this embodiment. In this embodiment, as shown in the figure, springs 61, 62, 63 (examples of the first elastic body and the second elastic body in the present invention) are attached to the back side of the MP joint 21, the PIP joint 22, and the DIP joint 23, respectively. are provided. The arrangement of the

springs

61, 62, 63 is the same as in Example 1 except for the difference between the back side of the hand and the palm side. However, the

springs

61, 62, and 63 in this embodiment are tension coil springs, and exert a tensile force on each joint of the finger F in the extension direction. The wire rod W1 is passed through the

springs

61, 62 and 63. As shown in FIG. The wire W1 needs to be loosened when the finger F is bent, but by passing through the

springs

61, 62, 63, it is less likely to get caught on other members.

Assuming that the spring constants of the

springs

61, 62, and 63 are k1, k2, and k3, respectively, the

springs

61, 62, and 63 that satisfy k1>k2>k3 are used. Therefore, when a tensile force is applied to the wire rod W2, the DIP joint 23, the PIP joint 22, and the MP joint 21 are bent in this order as described above.

Although compression coil springs are used as the

springs

61, 62, and 63, leaf springs may be used.

As in the modified example of the first embodiment, as a modified example of this embodiment, the

springs

61, 62, 63 can be a single spring 6 as shown in FIG. 6(b).

By arranging the

springs

61, 62, 63 with different spring constants at the joints on the back side of the hand in this way, the joints with the springs with the smaller spring constants can be bent in order.

In the case of Embodiments 1 and 2, since the

springs

61, 62, and 63 apply biasing force or tensile force in the direction of extending the joint, it is possible to adopt a configuration in which the wire rod W1 is not provided. Further, when the wire rod W1 is provided, when the tensile force of the wire rod W2 is released, the joints are displaced to the extended state by the action of the

springs

61, 62, and 63. Therefore, the wire rod W1 may be used as a support for the tension of the wire rod W1. do not need to be maintained.

FIG. 7 is a side sectional view of the index finger F2 in this embodiment. In this embodiment, the robot hand H is covered with a covering elastic body 7 that imitates the muscles, skin, etc. of a human hand in order to approximate the tactile sensation of a human hand. As the covering elastic body 7, a material such as rubber, silicon rubber, urethane gel, etc., which is elastically deformed while generating an appropriate repulsive force when the finger F is bent can be used. The repulsive force is the force that resists tensile force on the back side of the hand, and the force that resists compressive force on the palm side.

In this embodiment, by varying the thickness of the palm side of each joint portion of the covering elastic body 7, the repulsive force acting on each joint is varied to control the bending order of the joints. In this embodiment,

concave portions

71, 72, and 73 are formed on the palm sides of the MP joint 21, the PIP joint 22, and the DIP joint 23 of the covering elastic body 7, respectively, so that the thickness of each joint portion of the covering elastic body 7 is reduced. making it different. Specifically, by making the recessed portion 73 the largest and the recessed portion 71 the smallest, the thickness of the covering elastic body 7 near the DIP joint 23 is made the thinnest, and the thickness of the covering elastic body 7 near the MP joint 21 is made the thickest. ing. As a result, the repulsive force near the concave portion 73 is the smallest, and the repulsive force near the concave portion 71 is the largest. In such an index finger F2, when a tensile force is applied to the wire rod W2, the DIP joint 23 having the largest concave portion starts to bend first, followed by the PIP joint 22 and the MP joint 21 in that order.

Of course, the method of differentiating the repulsive force is not limited to this, and can be changed, such as partially changing the hardness of the covering elastic body 7, as long as the object of the present invention is achieved. Also, the

springs

61, 62, 63 in the first and second embodiments can be used together. In that case, the repulsive force of the covering elastic body 7 should be set in consideration of the spring coefficients of the

springs

61, 62 and 63. FIG.

In this embodiment, the extension state of the MP joint 21 can be maintained, and only the PIP joint 22 and the DIP joint 23 can be bent. FIG. 8 is a side sectional view showing the bending motion of the index finger F2 in this embodiment. The index finger F2 in this embodiment is provided with a wire rod W3 that applies tensile force to the proximal phalanx 12. As shown in FIG. One end of the wire W3 is fixed to the proximal phalanx 12 near the metacarpal bone 11 near the back of the hand, and the other end is connected to an actuator or the like (not shown). Note that other configurations such as the first elastic body and the second elastic body are not shown in FIG. 8 because any of the above-described embodiments can be used.

When the wire rod W2 is pulled with a tension force applied to the wire rod W3 with respect to the index finger F having such a structure, the DIP joint 23, which is the easiest to bend, first bends (FIG. 8(a)), and then the PIP joint 23 bends (FIG. 8A). The joint 22 bends (FIG. 8(b)). When the wire rod W2 is further pulled, the MP joint 21 bends in the above embodiment, but in the present embodiment, the tensile force of the wire rod W3 inhibits bending of the MP joint 21, so only the DIP joint 23 and the PIP joint 22 are bent. Continue bending (FIGS. 8(c)-(e)). By controlling the tensile force of W3, it is also possible to bend the MP joint 21 from the time when the DIP joint 23 and the PIP joint 22 reach the predetermined bending positions.

Thus, in the configuration of this embodiment, the bending of the MP joint 21 can be controlled independently of the bending of other joints.

As described above, the finger F of the robot hand H according to the present invention controls the bending order of the joints by the difference in the elastic force of the elastic bodies (the first elastic body and the second elastic body) provided at each joint. be able to. Further, when springs are used as the first elastic body and the second elastic body, they can be used as passages for wires that apply a tensile force to the finger F. FIG. In that case, it is possible to prevent the wire from getting caught on other members or surrounding objects.

It should be noted that when metal wires are used as the wire rods W1 and W2, the wire rods may become bent after repeated use. The tendency of the wire to bend is more likely to occur as the wire is bent more during use. That is, the wire rod W2 arranged on the palm side is more prone to bending than the wire rod W1 arranged on the back side of the hand. The above-described embodiments also show how to solve this problem. Specifically, the

springs

61, 62, and 63, which are passageways for the wire rod W2, are only fixed at both ends of the

springs

61, 62, and 63 at each joint portion, and the intermediate portions thereof are exposed. These springs can be displaced inward when the joint is flexed by the action of the force. Due to this displacement of the spring, the curvature of the wire rod W2 is slightly reduced, and it is possible to reduce the tendency to bend.

This effect depends on the length of the spring provided in the joint from the fixed position on the wrist side to the fixed position on the fingertip side. Specifically, the longer the length from the fixed position on the wrist side of the spring to the fixed position on the fingertip side, the smaller the curvature of the wire rod W2 can be. FIG. 9 is a cross-sectional view near the PIP joint 22 in a bent state, showing changes in the curvature of the spring. In addition, in FIG. 9, the spring 62 is hatched for easy identification. FIG. 9(a) shows a state in which the spring 62 is fixed to the front end of the pressing member 12c and the rear end of the pressing member 13c. FIG. 9(b) shows a state in which the spring 62 is fixed to the front end of the pressing member 12c and the fingertip side end surface of the concave portion formed at the rear end of the pressing member 13c. FIG. 9(c) shows a state in which the spring 62 is fixed to the wrist-side end surface of the recess formed at the front end of the pressing member 12c and the fingertip-side end surface of the recess formed at the rear end of the pressing member 13c. As shown in these figures, the longer the length from the fixed position on the wrist side of the spring to the fixed position on the fingertip side, the smaller the curvature of the spring 62 and the curvature of the wire rod W2 passing through it. is also smaller.

In addition, the robot hand H according to the present invention can easily perform finger picking, which was difficult with conventional robot hands. For example, when each joint of the forefinger F2 of the above-described embodiment is flexed and the distal phalanx 14 is pressed by the thumb F1 so as not to extend, the thumb F1 is shifted, and each joint is vigorously moved by the restoring force of the spring 61 and the like. Extends and becomes a finger-picking motion.

[Another embodiment]
(1) In the above embodiment, the finger F is displaced from the extended state to the bent state, but it may be displaced from the bent state to the extended state. Even in this case, the extension order of the joints can be controlled by varying the elastic force acting on each joint, as in the above-described embodiment.

(2) In the first and second embodiments described above, the

springs

61, 62 and 63 are provided at the MP joint 21, the PIP joint 22 and the DIP joint 23. It can also be configured without For example, the configuration may be such that the spring 63 of the DIP joint 23 in the first and second embodiments is not provided.

(3) As long as the objects of the present invention are achieved, the above-described embodiments can be modified as appropriate, and combinations of the embodiments are also possible.

The present invention can be used not only for conventionally known applications such as manufacturing sites and artificial hands, but also for remote communication systems. In such a remote communication system, for example, the robot hand H and the monitor according to the present invention are installed at the first point where the first user is, and the movement of the hand such as a data glove is detected at the second point where the second user is. Install sensors and cameras that can The image captured by the camera at the second location is displayed on the monitor at the first location, and the first user can visually recognize the second user. Further, when the sensor senses the motion of the second user to hold the hand at the second point, the information is reflected in the motion of the robot hand H at the first point, and the robot hand H grasps the first user's hand. Flex the joint of the finger F. By using such a remote communication system, it is possible to make a pseudo physical contact, and it is possible to enhance a sense of familiarity even though the two are physically separated from each other.

A1: Rotation axis A2: Rotation axis A3: Rotation axis H: Robot hand F: Finger (articulated finger)
F1: thumb (multi-joint finger)
F2: index finger (multi-joint finger)
F3: middle finger (multi-joint finger)
F4: ring finger (multi-joint finger)
F5: little finger (multi-joint finger)
W1: wire rod W2: wire rod (bending force acting portion)
11: metacarpal bone 12: proximal phalanx 13: middle phalanx
14: Distal phalanx 21: MP joint 22: PIP joint 23: DIP joint 24: IP joint 6: Spring (first elastic body, second elastic body)
61: Spring 62: Spring 63: Spring 7: Covered elastic body

Claims

A robot hand with articulated fingers,
The articulated finger includes at least a first finger, a second finger, and a third finger,
the second finger is connected to the vicinity of the fingertip side end of the first finger so as to be rotatable about a first rotation axis to form a bendable/extendable first joint;
the third finger is connected to the vicinity of the fingertip side end of the second finger so as to be rotatable about a second rotation axis to form a bendable/extendable second joint;
a bending force acting portion that applies a bending force to the first joint and the second joint;
a first elastic body provided near the first joint and generating an extension force that resists the bending force acting on the first joint;
a second elastic body provided near the second joint and generating an extension force that resists the bending force acting on the second joint;
The extension force of the second elastic body is smaller than the extension force of the first elastic body.
The robot hand according to claim 1, wherein the first elastic body and the second elastic body are springs, and the spring constant of the second elastic body is smaller than the spring constant of the first elastic body.
It is fixed to the first finger and the second finger so as to straddle the first joint to constitute the first elastic body, and the second finger and the second finger to straddle the second joint. A single coil spring that is fixed to the three fingers and constitutes the second elastic body,
3. The robot hand according to claim 2, wherein the number of turns of said second elastic body is smaller than the number of turns of said first elastic body.
The first elastic body and the second elastic body are compression coil springs provided on the palm side, and the bending force acting portion is a wire, or the first elastic body and the second elastic body are provided on the back side of the hand. A wire rod that is a tension coil spring and applies an extension force to the first joint and the second joint,
4. The robot hand according to claim 2, wherein said wire is inserted through said coil spring.
A covering elastic body covering the articulated finger is provided,
the first elastic body and the second elastic body are parts of the covered elastic body positioned near the first joint and the second joint, respectively;
2. The robot hand according to claim 1, wherein the repulsive force of said second elastic body is smaller than the repulsive force of said first elastic body.