Linkage mechanism and end effector

Abstract

To make it possible to reduce a peak value of a load toward a rotation axis in a link mechanism in which two links are so connected as to be relatively rotatable around the rotation axis, and an end effector comprising the link mechanism.SOLUTION: Link mechanisms 23, 25 comprise: first links 9, 11; second links 11, 13 which are connected to the first link so as to be relatively rotatable around rotation axes X, Y; and energization means 45, 45A, 45B which apply energization force against a load toward the rotation axes, which are added to the second link, to the second link.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a link mechanism in which two links are connected so as to be relatively rotatable, and an end effector provided with the link mechanism.

Background Art

[0002] A finger joint mechanism of a robot hand is known (for example, Patent Document 1). The finger joint mechanism of Patent Document 1 includes a palm dividing portion, a first finger member connected to the palm dividing portion via a first joint, and a second finger member connected to the first finger member via a second joint.

[0003] The first finger member is rotatable about the axis of the first joint axis with respect to the palm dividing portion, and the second finger member is rotatable about the axis of the second joint axis with respect to the first finger member.

[0004] A first link axis parallel to the first joint axis is fixed to the palm dividing portion. A second link axis parallel to the second joint axis is provided rotatably about the axis on the second finger member. A coil spring is stretched between the first link axis and the second link axis. When an impact force or an overload force is input to the second finger member, the coil spring functions as a buffer member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0008] To solve the above problems, one aspect of the present invention is a link mechanism (23, 25) comprising: a first link (9, 11); a second link (11, 13) connected to the first link so as to be rotatable relative to a rotation axis (X, Y); and a biasing means (45, 45A, 45B) that applies a biasing force to the second link to resist a load applied to the second link toward the rotation axis.

[0009] In this embodiment, when a load is applied toward the axis of rotation, a biasing force is applied by the biasing means to resist that load. Therefore, the peak value of the load toward the axis of rotation can be mitigated by the biasing means.

[0010] In the above embodiment, preferably, the first link comprises a base (31) and shaft portions (33, 33A, 33B) extending along the rotation axis to which the second link is rotatably connected, and the biasing means is provided between the base and the shaft portions.

[0011] According to this embodiment, the first link and the second link can be connected so as to be able to rotate relative to each other around the axis of rotation, and a biasing means can be provided to apply a biasing force to the second link that is directed toward the axis of rotation.

[0012] In the above embodiment, preferably, the base comprises a cylindrical portion (43, 43A, 43B) that receives and fixes the shaft portion, and a main body portion (41) that surrounds the cylindrical portion at a distance (44), and the biasing means is provided between the cylindrical portion and the main body portion.

[0013] According to this embodiment, the first link and the second link can be connected so as to be able to rotate relative to each other around the axis of rotation, and a biasing means can be provided to apply a biasing force to the second link that is directed toward the axis of rotation.

[0014] In the above embodiment, preferably, the biasing means comprises at least one leaf spring (45, 45A, 45B) extending in the direction of the rotation axis and in the circumferential direction of the rotation axis, wherein the leaf spring extends from the cylindrical portion toward one direction around the rotation axis and away from the rotation axis, and is connected to the main body portion.

[0015] According to this embodiment, the biasing means can be configured simply.

[0016] In the above embodiment, preferably, the width of the leaf spring in the direction along the axis of rotation is greater than the thickness of the leaf spring.

[0017] According to this embodiment, it is possible to prevent movement of the shaft portion in a direction parallel to the axis of rotation.

[0018] To solve the above problems, one aspect of the present invention is an end effector (1) comprising the link mechanism described above and a drive source (21) that causes the first link and the second link to rotate relative to each other about the rotation axis.

[0019] According to this embodiment, when a load is applied toward the axis of rotation, a biasing force is applied by the biasing means to resist that load. Therefore, an end effector can be provided that has two links rotatably mounted via the axis of rotation, and in which the peak value of the load toward the axis of rotation can be mitigated by the biasing means. [Effects of the Invention]

[0020] According to the above embodiment, in a link mechanism in which two links are connected so as to be able to rotate relative to each other around a rotation axis, and in an end effector equipped with the link mechanism, the peak value of the load directed toward the rotation axis can be mitigated.

Brief Description of the Drawings

[0021] [Figure 1] Perspective view of the finger part (end effector) of the robot hand according to the embodiment [Figure 2] Side view of the base of the middle link [Figure 3] Cross-sectional view taken along line III-III of FIG. 1 [Figure 4] Perspective view of the base of the middle link [Figure 5] Side view for explaining the structure of the leaf spring part of the base of the middle link

Mode for Carrying Out the Invention

[0022] An embodiment in which the link mechanism and end effector according to the present invention are applied to the finger part provided at the tip of the robot arm of the humanoid robot will be described with reference to the drawings.

[0023] As shown in FIG. 1, the finger part 1 is connected to the palm part 3 that constitutes a part corresponding to the palm of a human. In the present embodiment, five finger parts 1 are connected to one palm part 3, and the robot hand has a shape imitating a human hand.

[0024] The palm part 3 includes a wrist part (not shown) corresponding to the human carpal bone and a plurality of middle hand links 7 corresponding to the human metacarpal bones. The middle hand links 7 are each connected to the wrist part. In the present embodiment, five middle hand links 7 are provided on the palm part 3.

[0025] Each finger part 1 includes a proximal link 9 corresponding to the human proximal phalanx, a middle link 11 (first link) corresponding to the human middle phalanx, and a distal link 13 (second link) corresponding to the human distal phalanx.

[0026] The base link 9 is rod-shaped and extends in a predetermined direction. At one end, the base link 9 is connected to the metacarpal link 7 so as to be able to rotate relative to it around two axes perpendicular to it (the directions of axes L and M in Figure 1). Hereinafter, the connection between the base link 9 and the metacarpal link 7 will be referred to as the M joint 15 (or MP joint).

[0027] The intermediate link 11 is also rod-shaped and extends in a predetermined direction. At one end, the intermediate link 11 is connected to the other end of the base link 9 so as to be able to rotate relative to it around a predetermined axis of rotation (hereinafter referred to as the first axis of rotation X). Hereinafter, the connection between the intermediate link 11 and the base link 9 will be referred to as the P joint 17 (or PIP joint).

[0028] The end link 13 is also rod-shaped and extends in a predetermined direction. At one end, the end link 13 is connected to the other end of the middle link 11 so as to be able to rotate relative to it around a predetermined axis of rotation (hereinafter referred to as the second axis of rotation Y). The other end of the end link 13 is a free end. Hereinafter, the connection between the end link 13 and the middle link 11 will be referred to as the D joint 19 (or DIP joint).

[0029] The finger portion 1 is provided with a drive source 21 that rotates the proximal phalangeal link 9, the middle phalangeal link 11, and the distal phalangeal link 13 relative to each other. Driven by the drive source 21, the finger portion 1 is displaced between an extended position (see Figure 1) in which the proximal phalangeal link 9, the middle phalangeal link 11, and the distal phalangeal link 13 are aligned in a straight line, and a flexed position in which one of the M joint 15, P joint 17, and D joint 19 is flexed.

[0030] The intermediate link 11 may be rotationally driven by a drive source 21 via wires 27 (i.e., wire-driven). For example, the intermediate link 11 may be connected to the drive source 21 via two wires 27 and rotated relative to each other in both directions. Specifically, the drive source 21 may be configured as a motor, and the drive source 21 pulling one wire 27 causes the intermediate link 11 to rotate relative to the base link 9 in one direction. The drive source 21 pulling the other wire 27 causes the intermediate link 11 to rotate relative to the base link 9 in the other direction. Alternatively, the intermediate link 11 may be connected to the drive source 21 via one wire 27, rotated in one direction by the drive source 21, and rotated in the other direction by a biasing force such as a spring.

[0031] The end link 13 may be rotationally driven by the drive source 21 via a wire 27, and a wire 27 or link mechanism may be provided between the base link 9 and the end link 13, or between the middle link 11 and the end link 13, so that the end link 13 rotates in response to the rotation of the base link 9 and the middle link 11.

[0032] As described above, the finger portion 1 is provided with a link mechanism (hereinafter referred to as the first link mechanism 23) in which the base joint link 9 and the middle joint link 11 are connected so as to be able to rotate relative to each other about a first rotation axis X, and a link mechanism (hereinafter referred to as the second link mechanism 25) in which the middle joint link 11 and the end joint link 13 are connected so as to be able to rotate relative to each other about a second rotation axis Y. In this embodiment, the first rotation axis X and the second rotation axis Y are configured to be parallel.

[0033] As shown in Figure 2, the P joint 17 and the D joint 19 are each provided with a structure that absorbs the impact based on the load applied to the tip of the finger 1. In this embodiment, the structure that absorbs the impact based on the load applied to the tip of the finger 1 is provided in the middle joint link 11. The configuration of the middle joint link 11 will be described in detail below with reference to the drawings.

[0034] As shown in Figures 2, 3, and 4, the intermediate link 11 is composed of a flat plate-shaped member. The intermediate link 11 may be made of resin, or it may be made of metal or the like. As shown in Figure 3, the intermediate link 11 comprises a base portion 31 and a shaft portion 33. In this embodiment, the intermediate link 11 comprises two shaft portions 33. The base portion 31 is formed by integral molding from a material such as resin.

[0035] As shown in Figures 2 and 4, the base 31 has a main body 41, a cylindrical portion 43, and a leaf spring 45 connecting the main body 41 and the cylindrical portion 43. In this embodiment, the base 31 has two cylindrical portions 43 and a plurality of leaf springs 45 connecting each cylindrical portion 43 to the main body 41.

[0036] As shown in Figure 2, the main body portion 41 extends in the direction of extension of the middle section link 11 and constitutes the outer shape of the middle section link 11. The base portion 31 may be oval in shape or gourd-shaped.

[0037] As shown in Figure 3, the main body portion 41 is provided with two through holes 51 that penetrate in the thickness direction. One through hole 51 (hereinafter referred to as the first through hole 51A) is provided at the end on the base link 9 side, and the other through hole 51 (hereinafter referred to as the second through hole 51B) is provided at the end on the end link 13 side. In this embodiment, both the first through hole 51A and the second through hole 51B are circular in shape. As shown in Figure 2, the first through hole 51A is larger than the second through hole 51B, and the inner diameter of the first through hole 51A is larger than the inner diameter of the second through hole 51B.

[0038] As shown in Figure 2, the base portion 31 is provided with two cylindrical portions 43. Each cylindrical portion 43 is located approximately at the center of the corresponding through hole 51, and a gap 44 is formed between the inner circumferential surface of the through hole 51 and the cylindrical portion 43. More specifically, as shown in Figure 3, at least a portion of one cylindrical portion 43 (hereinafter referred to as the first cylindrical portion 43A) is housed inside the first through hole 51A, and at least a portion of the other cylindrical portion 43 (hereinafter referred to as the second cylindrical portion 43B) is housed inside the second through hole 51B. The first cylindrical portion 43A and the second cylindrical portion 43B are each surrounded by the main body portion 41 with a gap (gap 44) between them.

[0039] As shown in Figure 4, the first cylindrical portion 43A is cylindrical in shape. As shown in Figure 3, one of the two shaft portions 33 (hereinafter referred to as the first shaft portion 33A) is received in the first cylindrical portion 43A. The first shaft portion 33A is substantially cylindrical in shape. The first shaft portion 33A is press-fitted into the first cylindrical portion 43A and fixed in place. A base link 9 is connected to the first shaft portion 33A via a sliding bearing 47A. As a result, the base link 9 is connected to the first shaft portion 33A so as to be rotatable relative to it.

[0040] The base link 9 is connected to the first shaft portion 33A so as to be rotatable relative to it, the first shaft portion 33A is fixed to the first cylindrical portion 43A, and the first cylindrical portion 43A is connected to the main body portion 41 via a leaf spring 45. Therefore, the base link 9 is connected to the main body portion 41 of the intermediate link 11 so as to be rotatable relative to it about the axis of the first shaft portion 33A. In other words, the axis of the first shaft portion 33A corresponds to the first rotation axis X described above.

[0041] As shown in Figure 4, the second cylindrical portion 43B is cylindrical in shape. As shown in Figure 3, one of the two shaft portions 33 (hereinafter referred to as the second shaft portion 33B) is received in the second cylindrical portion 43B. The second shaft portion 33B is substantially cylindrical in shape. The second shaft portion 33B is press-fitted into the second cylindrical portion 43B and fixed in place. The end link 13 is connected to the second shaft portion 33B via a sliding bearing 47B. As a result, the end link 13 is connected to the second shaft portion 33B so as to be rotatable relative to it.

[0042] The end link 13 is connected to the second shaft portion 33B so as to be rotatable relative to it, the second shaft portion 33B is fixed to the second cylindrical portion 43B, and the second cylindrical portion 43B is connected to the main body portion 41 via a leaf spring 45. Therefore, the end link 13 is connected to the main body portion 41 of the middle link 11 so as to be rotatable relative to it about the axis of the second shaft portion 33B. In other words, the axis of the second shaft portion 33B corresponds to the second rotation axis Y mentioned above.

[0043] As shown in Figure 4, the middle section link 11 is provided with a plurality of leaf springs 45 (hereinafter referred to as first leaf springs 45A) that connect the first cylindrical portion 43A and the main body portion 41, and a plurality of leaf springs 45 (hereinafter referred to as second leaf springs 45B) that connect the second cylindrical portion 43B and the main body portion 41.

[0044] As shown in Figure 5, the first leaf spring 45A is plate-shaped and extends in the axial direction of the first shaft portion 33A (i.e., the direction of the first rotation axis X) and in the circumferential direction of the axial direction of the first shaft portion 33A. The first leaf spring 45A connects the outer circumferential surface of the first cylindrical portion 43A to the inner circumferential surface of the first through hole 51A of the main body portion 41 (the wall surface defining the first through hole 51A). In detail, the first leaf spring 45A extends from the first cylindrical portion 43A in one direction around the first rotation axis X, away from the first rotation axis X, and is connected to the main body portion 41.

[0045] As shown in Figure 4, the width of the first leaf spring 45A in the direction along the first rotation axis X is set to be greater than the thickness of the first leaf spring 45A.

[0046] In this embodiment, as shown in Figure 5, four first leaf springs 45A are provided between the outer circumferential surface of the first cylindrical portion 43A and the inner circumferential surface of the first through hole 51A. The four first leaf springs 45A have the same shape. The four first leaf springs 45A are rotationally symmetric with respect to the center line of the first through hole 51A and are arranged at equal intervals in the circumferential direction.

[0047] The four first leaf springs 45A are identical in shape and are arranged rotationally symmetrically with respect to the center line of the first through hole 51A. Therefore, when no load is applied to the first cylindrical portion 43A, the first cylindrical portion 43A is located at the center of the first through hole 51A. Thus, the axis of the first shaft portion 33A, i.e., the first rotation axis X, coincides with the center line of the first through hole 51A, and the first rotation axis X passes through the center of the first through hole 51A in its through direction.

[0048] In a side view of the middle section link 11, the angle θA formed by the semi-linear line connecting the central axis of the first cylindrical portion 43A and the connection point of the first leaf spring 45A to the outer circumferential surface of the first cylindrical portion 43A, and the semi-linear line connecting the central axis of the first cylindrical portion 43A and the connection point of the inner circumferential surface of the first through hole 51A of the first leaf spring 45A, should be set to 90 degrees or more and less than 180 degrees. Here, the connection point of the first leaf spring 45A to the outer circumferential surface of the first cylindrical portion 43A means the midpoint in the circumferential direction of the portion where the first leaf spring 45A and the first cylindrical portion 43A are connected, and the connection point of the inner circumferential surface of the first through hole 51A of the first leaf spring 45A means the midpoint in the circumferential direction of the portion where the first leaf spring 45A and the inner circumferential surface of the first through hole 51A are connected.

[0049] As shown in Figure 5, the second leaf spring 45B is plate-shaped and extends in the axial direction of the second shaft portion 33B (i.e., in the direction of the second rotation axis Y) and in the circumferential direction of the axial direction of the second shaft portion 33B. The second leaf spring 45B connects the outer circumferential surface of the second cylindrical portion 43B to the inner circumferential surface of the second through hole 51B of the main body portion 41 (the wall surface defining the second through hole 51B). In detail, the second leaf spring 45B extends from the second cylindrical portion 43B in one direction around the second rotation axis Y, away from the second rotation axis Y, and is connected to the main body portion 41.

[0050] As shown in Figure 4, the width of the second leaf spring 45B in the direction along the second rotation axis Y is set to be greater than the thickness of the second leaf spring 45B.

[0051] In this embodiment, as shown in Figure 5, four second leaf springs 45B are provided between the outer circumferential surface of the second cylindrical portion 43B and the inner circumferential surface of the second through hole 51B. The four second leaf springs 45B have the same shape. The four second leaf springs 45B are rotationally symmetric with respect to the central axis of the second cylindrical portion 43B and are arranged at equal intervals in the circumferential direction.

[0052] The four second leaf springs 45B are identical in shape and are arranged rotationally symmetrically with respect to the center line of the second through hole 51B. Therefore, when no load is applied to the second cylindrical portion 43B, the second cylindrical portion 43B is located at the center of the second through hole 51B. Thus, the axis of the second shaft portion 33B, i.e., the second rotation axis Y, coincides with the center line of the second through hole 51B, and the second rotation axis Y passes through the center of the second through hole 51B in its through direction.

[0053] In a side view of the middle section link 11, the angle θB formed by the semi-linear line connecting the central axis of the second cylindrical portion 43B and the connection point of the second leaf spring 45B to the second cylindrical portion 43B, and the semi-linear line connecting the central axis of the second cylindrical portion 43B and the connection point of the inner circumferential surface of the second through hole 51B of the second leaf spring 45B, should be set to 90 degrees or more and less than 180 degrees. Here, the connection point of the second leaf spring 45B to the second cylindrical portion 43B means the midpoint in the circumferential direction of the portion where the second leaf spring 45B and the second cylindrical portion 43B are connected, and the connection point of the inner circumferential surface of the second through hole 51B of the second leaf spring 45B means the midpoint in the circumferential direction of the portion where the second leaf spring 45B and the inner circumferential surface of the second through hole 51B are connected.

[0054] As shown in Figure 4, the width of the first leaf spring 45A in the direction along the first rotation axis X is set to be greater than the width of the second leaf spring 45B in the direction along the second rotation axis Y. In this embodiment, the thickness of the first leaf spring 45A is further set to be greater than the thickness of the second leaf spring 45B.

[0055] In addition, as shown in Figure 4, the middle section link 11 is provided with a groove 53 (see also Figure 1) for attaching a wire 27 for driving the middle section link 11 and the end section link 13, and a locking portion 55 for securing the wire 27.

[0056] Next, the operation and effects of the link mechanism configured in this way (first link mechanism 23 and second link mechanism 25) and the finger part 1 (end effector) will be explained.

[0057] When the proximal link 9, the middle link 11, and the distal link 13 are arranged in a straight line, that is, when the finger portion 1 is extended (see Figure 1), an impact force may be applied to the tip of the finger portion 1, resulting in a load directed toward the palm portion 3.

[0058] At this time, a load directed toward the second rotation axis Y is applied to the end link 13. As a result, a load directed toward the second rotation axis Y is also applied to the second shaft portion 33B and the second cylindrical portion 43B via the sliding bearing 47B.

[0059] The load applied to the second cylindrical portion 43B in the direction of the second rotation axis Y acts to shift the second cylindrical portion 43B away from the center of the second through hole 51B. As a result, the second leaf springs 45B each bend, and the second leaf springs 45B apply a biasing force to the second cylindrical portion 43B and the main body portion 41 to resist the load. In this way, the load in the direction of the second rotation axis Y is mitigated by the second leaf springs 45B (biasing means), and the second link mechanism 25 is protected.

[0060] The load applied to the end link 13 may also be transmitted to the middle link 11. At this time, a load directed toward the first rotation axis X may be applied to the main body 41. As a result, a load is applied to the main body 41 such that the first cylindrical portion 43A is shifted away from the axis of the first through hole 51A. This causes the first leaf springs 45A to bend, and a biasing force is applied from the first leaf springs 45A to the first cylindrical portion 43A and the main body 41 in opposition to the load. As a result, the load directed toward the first rotation axis X is absorbed by the first leaf springs 45A (biasing means), and the first link mechanism 23 is protected.

[0061] The first leaf spring 45A and the second leaf spring 45B are each provided between the base portion 31 and the cylindrical portion 43. This allows a biasing force to be applied to the middle section link 11 that is directed toward the first rotation axis X and the second rotation axis Y. Therefore, even when a load similar to that applied to a human finger during a jammed finger is applied, the first leaf spring 45A and the second leaf spring 45B can alleviate the load, thus creating a finger portion 1 (end effector). In this way, the first leaf spring 45A and / or the second leaf spring 45B alleviate the peak value of the load, thereby protecting the finger portion 1.

[0062] Furthermore, in this embodiment, when a load is applied that causes the first shaft portion 33A and the second shaft portion 33B to rotate about their respective axes, the first leaf spring 45A and / or the second leaf spring 45B elastically deform and apply a biasing force to resist the load. In this way, the first leaf spring 45A and the second leaf spring 45B function as omnidirectional springs, and can alleviate not only linear loads directed toward the first rotation axis X and the second rotation axis Y, but also moment loads that cause relative rotation of each link.

[0063] The second leaf spring 45B is configured to be plate-shaped, extending in the direction of extension of the second rotation axis Y and in the circumferential direction of the second rotation axis Y. The second leaf spring 45B extends from the outer circumferential surface of the second cylindrical portion 43B toward one direction around the second rotation axis Y, away from the second rotation axis Y, and is connected to the main body portion 41.

[0064] This allows the second leaf spring 45B to be configured to resist a load that displaces the second cylindrical portion 43B relative to the main body portion 41. This allows the second leaf spring 45B to be configured so that it can apply a biasing force to the end link 13 that resists a load directed toward the second rotation axis Y or a load moving away from the second rotation axis Y.

[0065] Similarly, the first leaf spring 45A is configured to be plate-shaped, extending in the direction of extension of the first rotation axis X and in the circumferential direction of the first rotation axis X. The first leaf spring 45A extends from the outer circumferential surface of the first cylindrical portion 43A toward one side around the first rotation axis X, in a direction away from the first rotation axis X, and is connected to the main body portion 41.

[0066] This allows the first leaf spring 45A to be configured to resist loads that displace the first cylindrical portion 43A relative to the main body portion 41. This allows the first leaf spring 45A to be configured to provide a biasing force that resists loads applied to the middle section link 11 that are directed toward the first rotation axis X, and loads that shift the first cylindrical portion 43A away from the center of the first through hole 51A.

[0067] The first leaf spring 45A and the second leaf spring 45B provide a biasing force that resists the relative displacement of the first cylindrical portion 43A and the second cylindrical portion 43B with respect to the main body portion 41. In this way, the biasing means that provides the biasing force can be configured using the first leaf spring 45A and the second leaf spring 45B, resulting in a simple configuration for the biasing means. Furthermore, since the first leaf spring 45A and the second leaf spring 45B can be integrally molded with the main body portion 41, the number of components constituting the finger portion 1 can be reduced compared to the case where the first leaf spring 45A and the second leaf spring 45B are constructed as separate parts, and the assembly man-hours can also be reduced.

[0068] The width of the first leaf spring 45A in the direction along the first rotation axis X is greater than its thickness. This prevents movement of the first shaft portion 33A in a direction parallel to the first rotation axis X. Similarly, since the width of the second leaf spring 45B in the direction along the first rotation axis X is greater than its thickness, movement of the second shaft portion 33B in a direction parallel to the second rotation axis Y is prevented.

[0069] In this embodiment, the width of the first leaf spring 45A in the direction along the first rotation axis X is set to be greater than the width of the second leaf spring 45B in the direction along the second rotation axis Y. Furthermore, the thickness of the first leaf spring 45A is set to be greater than the thickness of the second leaf spring 45B.

[0070] In this way, by reducing the thickness and width of the leaf spring 45 provided on the tip side of the finger portion 1, the spring constant of the biasing means provided at the joint located on the tip side (free end side) of the finger portion 1 can be reduced. As a result, the link provided on the tip side of the finger portion 1 (in this embodiment, the distal link 13) becomes more easily displaced in response to the load. This makes it possible to give the tip side of the finger portion 1 more flexibility than the proximal end side, similar to a human hand.

[0071] This concludes the description of specific embodiments, but the present invention is not limited to the above embodiments and can be broadly modified and implemented.

[0072] For example, the above embodiment shows an example in which a link mechanism (first link mechanism 23, second link mechanism 25) and an end effector are provided on the finger portion 1 of the robot hand of a humanoid robot. However, the device on which the link mechanism and end effector are provided can be any multi-jointed device, and may be applied to robots other than humanoids, robots equipped with a driving unit such as wheels, tracks, or omni-wheels as means of movement, immobile robots, and various industrial robots.

[0073] Furthermore, the specific configuration, arrangement, and quantity of each component or part, or the control procedure, can be modified as appropriate, as long as it does not depart from the spirit of the present invention. Also, not all of the components and procedures shown in the above embodiment are necessarily required, and can be selected as appropriate. In the above embodiment, the thickness and width of the leaf spring 45 provided at the joint located at the tip of the finger portion 1 were both reduced, but any configuration is acceptable as long as the spring constant of the biasing means (leaf spring 45) provided at the joint located at the tip is reduced. For example, the thickness and width of the leaf spring 45 provided at the joint located at the tip may be reduced, and the spring constant of the leaf spring 45 provided at the joint located at the free end may be reduced. [Explanation of symbols]

[0074] 1: Finger section (end effector) 9: Baseline Link 11: Middle section link 13: Final section links 21: Power source 23: First linkage mechanism 25: Second Link Mechanism 31: Base 33: Shaft 33A: 1st shaft part 33B: 2nd shaft part 41: Main body 43:Cylinder part 43A: 1st cylinder part 43B:Second cylinder part 44: Gap 45: Leaf spring 45A: First leaf spring 45B: Second leaf spring X: First axis of rotation Y: Second rotation axis

Claims

1. The first link, A second link is connected to the first link so as to be able to rotate relative to it about a first axis of rotation, A third link is connected to the second link so as to be able to rotate relative to it about the second axis of rotation, The system includes a drive source that rotates the first link or the third link relative to the second link, An end effector in which the first link, the second link, and the third link are arranged in order from the drive source toward the tip, A first shaft portion extending along the first rotation axis and connecting the first link and the second link so as to be able to rotate relative to each other, A second shaft portion extending along the second rotation axis and connecting the third link and the second link so as to be able to rotate relative to each other, A first biasing means that applies a biasing force to the first shaft that resists a load directed toward the first rotation axis applied to the first shaft, A second biasing means that applies a biasing force to the second shaft that resists the load applied to the second shaft that is directed toward the second rotation axis, It has, The spring constant of the first biasing means is greater than the spring constant of the second biasing means. The second link further comprises a base, The first biasing means is provided between the base and the first shaft portion. The second biasing means is an end effector provided between the base and the second shaft portion.

2. The aforementioned base is, A first cylindrical portion that receives the first shaft portion and to which the first shaft portion is fixed, A second cylindrical portion that receives the second shaft portion and to which the second shaft portion is fixed, The first cylindrical portion and the second cylindrical portion are each surrounded by a main body portion at a distance from each other, The end effector according to claim 1, wherein the first biasing means is provided between the first cylindrical portion and the main body portion, and the second biasing means is provided between the second cylindrical portion and the main body portion.

3. The first biasing means comprises a plurality of leaf springs that extend in the direction of the first rotation axis and in the circumferential direction of the first rotation axis and are arranged at intervals from one another. The end effector according to claim 2, wherein each of the multiple leaf springs extends from the first cylindrical portion toward one of the first rotation axes in a direction away from the first rotation axis and is connected to the main body portion.

4. The second biasing means comprises leaf springs that extend in the direction of the second rotation axis and in the circumferential direction of the second rotation axis and are spaced apart from each other. The end effector according to claim 2, wherein each of the multiple leaf springs extends from the second cylindrical portion toward one side of the second rotation axis and toward the second rotation axis, and is connected to the main body portion.

5. The second link is equipped with the first biasing means, The end effector according to any one of claims 1 to 4, wherein the first link is opposed to the first biasing means and comprises a pair of first bearings that each receive the first shaft portion.

6. The second link includes the second biasing means, The end effector according to any one of claims 1 to 4, wherein the third link is opposed to the second biasing means and comprises a pair of second bearings that each receive the second shaft portion.

7. The second link comprises the first biasing means and the second biasing means, The first link is provided with a pair of first bearings that face each other via the first biasing means and each receive the first shaft portion. The end effector according to any one of claims 1 to 4, wherein the third link is opposed to the second biasing means and comprises a pair of second bearings that each receive the second shaft portion.

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