End effector and method for driving end effector

Abstract

To provide an end effector which is connected to a base and can be rotationally driven in a biaxial direction by a wire and in which the wire is compactly arranged.SOLUTION: An end effector comprises: a first member 23 connected to a base rotatably around a first axis 1Z; a first driven pulley 33 fixed to the first member concentrically with the first axis; a first wire 63 which is wound around the first driven pulley, and rotates the first member with respect to the base; a second member 25 which is connected to the first member rotatably around a second axis 1Y extending in a direction different from a direction of the first axis; a second driven pulley 43 fixed to the second member concentrically with the second axis; and a second wire 67 which is wound around the second driven pulley, and rotates the second member, is provided with a first idler pulley 39 rotatably supported on the first member concentrically with the first axis. The second wire is wound around the first idler pulley between a second driving source and the second driven pulley.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an end effector provided at the tip of a robot arm and a method for driving the end effector. [Background technology]

[0002] BACKGROUND ART A robot hand is known in which a motor installed at each joint rotates each joint and bends and stretches a finger mechanism (for example, Patent Document 1).

[0003] BACKGROUND ART There is known a robot hand that bends a joint by transmitting the power of an actuator to the joint via a wire rope passed through a casing (see, for example, the conventional example in Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-287182 [Patent Document 2] Japanese Patent Application Publication No. 06-143179 Summary of the Invention [Problem to be solved by the invention]

[0005] It is conceivable to provide a robot hand or robot arm with a joint (two-axis joint) that can rotate in two axial directions, similar to, for example, a human wrist joint or a joint at the base of the thumb. However, in the robot hand of Patent Document 1, two motors corresponding to the respective degrees of rotational freedom must be provided in one two-axis joint, making it difficult to configure a rotatable two-axis joint.

[0006] Therefore, the inventors of the present application came up with the idea of ​​driving a biaxial joint using a cable in which a wire rope is passed through a casing, as described in the conventional example of Patent Document 2. However, the inventors of the present application realized that it would be difficult to accommodate such a cable in a biaxial joint because a large volume would be required to accommodate such a cable.

[0007] In view of the above background, the present invention aims to provide an end effector that is connected to a base and can be rotated in two axial directions by wires, and a method for driving the end effector, in which the wires are arranged compactly. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, one aspect of the present invention is an end effector (21A) including a first member (23) rotatably connected to a base (19) around a first axis (1Z), a first driven pulley (33) fixed to the first member coaxially with respect to the first axis, a first wire (63) wound around the first driven pulley and pulled by a first drive source (61) to rotate the first member around the first axis relative to the base, and a second wire (63) rotatably connected to the first member around a second axis (1Y) extending in a direction different from the first axis. A first idler pulley (39A) is provided, which has a second member (25), a second driven pulley (43) fixed to the second member coaxially with respect to the second axis, and a second wire (67) wound around the second driven pulley and pulled by a second driving source (65) to rotate the second member around the second axis relative to the first member, and is coaxial with the first axis and supported rotatably with respect to the first member, and the second wire is wound around the first idler pulley between the second driving source and the second driven pulley.

[0009] According to this aspect, the first wire is wound around the first driven pulley and connected to the first drive source. The second wire is wound around the first idler pulley and connected to the second drive source. The first driven pulley and the first idler pulley are arranged coaxially. Therefore, the direction in which the first wire is pulled out from the first driven pulley and the direction in which the second wire is pulled out from the first idler pulley can be roughly aligned, allowing the two wires to be arranged compactly.

[0010] In the above aspect, preferably, a second idler pulley (39B) is provided which is coaxial with the first axis and rotatably supported with respect to the first member, and which has a third member (27) rotatably connected to the second member around a third axis (2Y), a third driven pulley which rotates the third member around the third axis, and a third wire (71) which is wound around the third driven pulley and is pulled by a third driving source (69) to rotate the third member around the second axis, and the third wire is wound around the second idler pulley between the third driving source and the third driven pulley.

[0011] According to this aspect, the third wire is wound around the second idler pulley and connected to the third drive source. The first driven pulley, the first idler pulley, and the second idler pulley are arranged coaxially, so the pull-out direction of the first wire, the pull-out direction of the second wire, and the pull-out direction of the third wire can be roughly aligned, which allows the wire pull-out directions to be unified and the three wires to be arranged compactly.

[0012] In the above aspect, preferably, the winding direction of the second wire around the first idler pulley is opposite to the winding direction of the third wire around the second idler pulley.

[0013] According to this aspect, when the second member and the third member are rotated in the same direction, the torques generated are in opposite directions, so that the torque that can be generated in the first member can be reduced.

[0014] In the above aspect, preferably, the second axis and the third axis are parallel to each other, and the first member is provided with a plurality of auxiliary idler members (41) around which the second wire and the third wire are wound so that when the second member is rotated in the same direction relative to the first member and the third member is rotated in the same direction relative to the second member, the torque applied to the first member from the second driving source via the second wire and the torque applied to the first member from the third driving source via the third wire are in opposite directions.

[0015] According to this aspect, when the second member and the third member are rotated in the same direction, the torques generated are in opposite directions, so that the torque that can be generated in the first member can be reduced.

[0016] In the above aspect, preferably, the first driven pulley is connected via the first wire so as to be rotatably driven in both directions by the first driving source, the second driven pulley is connected via the second wire so as to be rotatably driven in both directions by the second driving source, the third driven pulley is connected via the third wire so as to be rotatable in one direction by the third driving source, and the third driven pulley is biased against the pulling direction of the third wire.

[0017] According to this embodiment, the joint portions of the first and second axes, which are closer to the base, are driven in both directions by the drive source. Because they are driven directly by the drive source, powerful bending and extension movements are possible. Meanwhile, the joint portion of the third axis, which is farther from the base, is driven by the drive source on one side, but is biased back on the other side, which reduces the number of wires that need to be laid in the joint portion.

[0018] In the above aspect, preferably, a third idler pulley (39C) is provided that is coaxial with the first idler pulley and rotatably supported by the first member, and the second wire is wound around the first idler pulley, the second driven pulley, and the third idler pulley in the stated order.

[0019] According to this embodiment, the second wire can be appropriately wound from the second idler pulley to the second driven pulley.

[0020] In the method for driving the end effector described above, when rotating only the second member, the first driving source is driven so as to cancel out the torque generated in the first driven pulley by driving the second driving source.

[0021] According to this aspect, when only the second member is rotated, torque is prevented from being generated in the first driven pulley due to the driving of the first driving source, thereby more reliably preventing rotation of the first member relative to the base. [Effects of the Invention]

[0022] As described above, according to the present invention, there is provided an end effector that is connected to a base and can be rotated in two axial directions by wires, and a method for driving the end effector, which allows the wires to be arranged compactly. [Brief explanation of the drawings]

[0023] [Figure 1] Schematic diagram of a robot equipped with an end effector according to the present invention. [Figure 2] Schematic diagram of a robot hand equipped with an end effector [Figure 3] A perspective view of the thumb (end effector) and an enlarged view of the area enclosed by the two-dot chain line. [Figure 4] An explanatory diagram for explaining the structure of the thumb part (end effector) [Figure 5] An explanatory diagram for explaining bending of the thumb (end effector) [Figure 6] FIG. 1 is a perspective view illustrating the wiring structure of the wires in the thumb portion according to the present invention; [Figure 7] Top view of the thumb (end effector) DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an end effector according to the present invention will be described in detail below with reference to the drawings.

[0025] 1, the end effector is provided on a humanoid robot (hereinafter referred to as robot 3). The robot 3 has a body 5 corresponding to a human body, a head 7 provided on the upper side of the body 5, two legs 9 extending downward from the body 5, and two arms 11 (robot arms) provided on the left and right sides of the body 5, respectively.

[0026] Like a human, the arm 11 has upper arms 13 connected at one end to the left and right sides of the torso 5, and lower arms 15 connected at the other end to the upper arms 13. The lower arms 15 are rotatably connected at one end to the upper arms 13 and extend in a predetermined direction. A robot hand 17 (hand) is provided at the other end (extending end) of the lower arms 15.

[0027] As shown in FIG. 2, the robot hand 17 includes a palm 19 and five fingers 21.

[0028] The palm portion 19 has a generally flat plate shape corresponding to a human palm. The palm portion 19 is connected to the extending end of the lower arm portion 15. The joint connecting the palm portion 19 and the lower arm portion 15 corresponds to the joint of a human wrist (radiocarpal joint). Because the joint of a human wrist is a biaxial joint, the palm portion 19 and the lower arm portion 15 are connected so as to be rotatable about two perpendicular axes.

[0029] The finger portions 21 are connected to the palm portion 19. The five finger portions 21 correspond to the thumb, index finger, middle finger, ring finger, and little finger, respectively. Each finger portion 21 has multiple joints. The robot 3 grasps an object by flexing and extending the joints of each finger portion 21.

[0030] The end effector constitutes at least one of these finger portions 21, and in this embodiment, the end effector constitutes the finger portion 21 corresponding to the thumb (hereinafter, thumb portion 21A).

[0031] Like a human thumb, the thumb portion 21A is connected at its base (proximal end) to the palm portion 19 via a joint. This joint corresponds to the thumb carpometacarpal joint of a human hand. Just as the thumb carpometacarpal joint is a biaxial joint, the thumb portion 21A is connected to the palm portion 19 so as to be rotatable about two axes.

[0032] The thumb 21A further has two joints corresponding to the metacarpophalangeal joint and the interphalangeal joint, respectively. These two joints are uniaxial joints, similar to the human thumb.

[0033] The structure of the thumb 21A (i.e., the end effector) will be described below with reference to Fig. 3, assuming that all joints are extended. In the following description, the extension direction of the thumb 21A is defined as the X-axis, the motion axis (rotation axis) of the joints of the thumb 21A other than the joint between the thumb 21A and the palm 19 is defined as the Y-axis, and the direction perpendicular to the X-axis and Y-axis is defined as the Z-axis. However, the names of the axes are for convenience of explanation, and the present invention is not limited to these names of the axes. The thumb 21A is connected to the palm 19 via a joint provided at its base end so as to be rotatable about the Y-axis and Z-axis.

[0034] As shown in FIG. 3, the thumb portion 21A has a base end member 23 (first member), a first link 25 (second member), a second link 27 (third member), a third link 29, and a drive mechanism 30 (see also FIG. 4).

[0035] The base end member 23 includes a flat main body 31 having a surface facing the Z-axis direction, a 1Z driven pulley 33 (first driven pulley) connected to the surface of the main body 31 on the positive side of the Z-axis, a protrusion 35 protruding from the 1Z driven pulley 33 in the positive direction of the Z-axis, and a cover member 37 covering the 1Z driven pulley 33 and the protrusion 35 from the positive direction of the Z-axis. The surface of the main body 31 facing the negative direction of the Z-axis is connected to the palm portion 19 (base) so as to be rotatable about an axis (first axis, hereinafter referred to as the 1Z axis) extending in the Z-axis direction. The protrusion 35 has a cylindrical shape extending in the positive direction of the Z-axis. The central axis of the protrusion 35 and the central axis of the 1Z driven pulley 33 each overlap the 1Z axis. Hereinafter, the connection between the base end member 23 and the palm portion 19 will be referred to as the 1Z joint.

[0036] Three idler pulleys 39 are rotatably supported on the protruding portion 35. Hereinafter, the idler pulleys 39 will be referred to as a first idler pulley 39A, a second idler pulley 39B, and a third idler pulley 39C in order from the negative Z-axis direction of the idler pulleys 39 (in order from the base end side of the protruding portion 35).

[0037] In this embodiment, the first idler pulley 39A, the second idler pulley 39B, and the third idler pulley 39C have the same shape and have smaller outer diameters than the 1Z driven pulley 33.

[0038] The cover member 37 is disposed on the side of the main body 31 facing the positive direction in the Z axis direction so as to cover the protrusion 35. The cover member 37 is fixed to the surface of the main body 31 facing the positive direction in the Z axis direction.

[0039] A plurality of auxiliary idler pulleys 41 (auxiliary idler members) for changing the wiring direction of the wires are provided at appropriate positions on the base end member 23. In this embodiment, five auxiliary idler pulleys 41 are provided on the base end member 23. Each auxiliary idler pulley 41 is cylindrical and supported by the base end member 23 so as to be rotatable about its axis.

[0040] Of the auxiliary idler pulleys 41, five auxiliary idler pulleys 41 (hereinafter referred to as auxiliary idler pulleys 41A to 41E) are each rotatably supported by the cover member 37, and one auxiliary idler pulley 41 (hereinafter referred to as auxiliary idler pulley 41F) is rotatably supported by the main body portion 31.

[0041] The first link 25 extends in the positive direction of the X-axis. At its base end (negative side of the X-axis), the first link 25 is coupled (i.e., pivotally supported) to the base-end member 23 so as to be rotatable about an axis (second axis; hereinafter, 1Y-axis) extending in the Y-axis direction. In this embodiment, the first link 25 is coupled at its base end to an end of the cover member 37 located in the positive direction of the Z-axis. Hereinafter, the connection portion between the first link 25 and the base-end member 23 will be referred to as the 1Y joint.

[0042] The first link 25 is connected to the base end member 23 so as to be rotatable around the 1Y-axis, and the base end member 23 is connected to the palm portion 19 so as to be rotatable around the 1Z-axis. Thus, the first link 25 is connected to the palm portion 19 via the base end member 23 so as to be rotatable around two perpendicular axes, the 1Y-axis and the 1Z-axis. The connection portion between the first link 25 and the base end member 23 and the connection portion between the base end member 23 and the palm portion 19 form a biaxial joint that corresponds to the thumb carpometacarpal joint of a human hand.

[0043] In this embodiment, the first link 25 is connected to the cover member 37 of the base end member 23 so as to be rotatable about the 1Y axis. A 1Y driven pulley 43 (second driven pulley) having an axis along the 1Y axis is fixed to the base end side of the first link 25.

[0044] Similar to first link 25, second link 27 also extends in the positive direction of the X-axis. Second link 27 is connected to the free end of first link 25 on the base end side so as to be rotatable about an axis (third axis, hereinafter referred to as 2Y axis) extending in the Y-axis direction. Hereinafter, the connection portion between first link 25 and second link 27 will be referred to as a 2Y joint.

[0045] First link 25 is provided with a 2Y driven pulley 45 (third driven pulley) for rotating second link 27. 2Y driven pulley 45 is disposed coaxially with the 1Y axis and is rotatably connected to first link 25. As shown in FIG. 4, 2Y driven pulley 45 is connected to second link 27 via a link mechanism (hereinafter, 2Y link mechanism 47). When 1Y driven pulley 43 rotates, the rotation is transmitted to second link 27 by 2Y link mechanism 47, and second link 27 rotates around the 2Y axis relative to first link 25.

[0046] Similar to the first link 25 and the second link 27, the third link 29 also extends in the positive direction of the X-axis. The base end of the third link 29 is connected to the free end of the second link 27 so as to be rotatable about an axis extending in the Y-axis direction (hereinafter referred to as the 3Y axis). The free end of the third link 29 is provided with the finger pad that constitutes the pad of a human finger. Hereinafter, the connection between the second link 27 and the third link 29 will be referred to as the 3Y joint.

[0047] The third link 29 is also connected to the second link 27 via a link mechanism (hereinafter, referred to as a 3Y link mechanism 49). As shown in FIG. 5 , when the second link 27 rotates relative to the first link 25, the rotation is transmitted to the third link 29 by the 3Y link mechanism 49, and the third link 29 rotates about the 3Y axis relative to the second link 27. In this embodiment, when the second link 27 rotates in a direction bending relative to the first link 25, the third link 29 also rotates in a direction bending relative to the second link 27. Similarly, when the second link 27 rotates in a direction extending along the first link 25, the third link 29 also rotates in a direction extending relative to the second link 27.

[0048] As shown in FIG. 4, the drive mechanism 30 includes a 1Z drive unit 51 for driving the base end member 23 to rotate about the 1Z axis relative to the palm portion 19, a 1Y drive unit 53 for driving the first link 25 to rotate about the 1Y axis relative to the base end member 23, a 2Y drive unit 55 for driving the second link 27 to rotate about the 2Y axis relative to the first link 25, and a control device 57.

[0049] The 1Z driving unit 51 includes a 1Z driving source 61 (first driving source) and a 1Z wire 63 (first wire) connected to the 1Z driving source 61 and wound around the 1Z driven pulley 33. In this embodiment, the 1Z wire 63 includes a first portion 63A connected to the 1Z driving source 61 at one end, extending in the positive direction of the X-axis, and wound around and fixed to the 1Z driven pulley 33 in a counterclockwise direction as viewed from the positive side of the Z-axis direction via an auxiliary idler pulley 41F provided in the main body 31. The 1Z wire 63 further includes a second portion 63B connected to the 1Z driving source 61 at one end, extending in the positive direction of the X-axis, and wound around and fixed to the 1Z driven pulley 33 in a clockwise direction from the positive side of the Z-axis direction.

[0050] The 1Z driving source 61 rotates the base end member 23 counterclockwise as viewed from the Z axis positive side by pulling one end of the first portion 63A of the 1Z wire 63. The 1Z driving source 61 also rotates the base end member 23 clockwise as viewed from the Z axis positive side by pulling one end of the second portion 63B of the 1Z wire 63. In this way, the driving of the 1Z driving source 61 causes the base end member 23 (i.e., the thumb portion 21A) to rotate in both directions around the 1Z axis.

[0051] 1Y driving unit 53 includes 1Y driving source 65 (second driving source) and 1Y wire 67 (second wire) connected at both ends to 1Y driving source 65 and wound around 1Y driven pulley 43. As shown in FIG. 6, 1Y wire 67 is connected at one end (hereinafter, bent end 67P) to 1Y driving source 65, wound around first idler pulley 39A, then wound around first auxiliary idler pulley 41A, and wound around 1Y driven pulley 43. Thereafter, 1Y wire 67 is wound around second auxiliary idler pulley 41B, wound around third idler pulley 39C, further wound around third auxiliary idler pulley 41C, and connected at the other end (hereinafter, extended end 67Q) to 1Y driving source 65. In this way, the auxiliary idler pulleys 41A to 41C guide the extension direction of the 1Y wire 67 so that it can be wound from the first idler pulley 39A to the 1Y driven pulley 43, and also guide the extension direction of the 1Y wire 67 so that it can be wound from the 1Y driven pulley 43 to the third idler pulley 39C.

[0052] In this embodiment, 1Y wire 67 is composed of two portions, a flexion side portion and an extension side portion. The flexion side portion (hereinafter referred to as 1Y flexion side wire 67A) is wound from 1Y drive source 65 around first idler pulley 39A, then wound around first auxiliary idler pulley 41A, and then wound around and fixed to 1Y driven pulley 43. The extension side portion (hereinafter referred to as 1Y extension side wire 67B) is wound from 1Y drive source 65 around third auxiliary idler pulley 41C, then wound around third idler pulley 39C, then wound around second auxiliary idler pulley 41B, and then wound around 1Y driven pulley 43 and fixed.

[0053] 1Y driving source 65 selectively winds up one end of 1Y wire 67 and pays out the other end, thereby rotating first link 25 in both directions around the 1Y axis. Specifically, 1Y driving source 65 pulls bending end 67P (end of 1Y bending side wire 67A), thereby rotating first link 25 around the Y axis in a direction in which thumb portion 21A bends. 1Y driving source 65 pulls extension end 67Q (end of 1Y extension side wire 67B), thereby rotating first link 25 around the Y axis in a direction in which thumb portion 21A extends.

[0054] The 2Y driving unit 55 includes a 2Y driving source 69 (third driving source) and a 2Y wire 71 (third wire) wound around the 2Y driven pulley 45.

[0055] 6, one end of 2Y wire 71 is connected to 2Y drive source 69, and is wound around second idler pulley 39B, then wound around fourth auxiliary idler pulley 41D and fifth auxiliary idler pulley 41E in that order, and then wound around 2Y driven pulley 45. In this embodiment, the other end of 2Y wire 71 is fixed to cover member 37 via return mechanism 72 (see FIG. 4). Return mechanism 72 serves to apply a biasing force to 2Y wire 71 that resists the tension applied to 2Y wire 71.

[0056] When 2Y drive source 69 is driven and pulls 2Y wire 71, 2Y driven pulley 45 rotates. As a result, 2Y link mechanism 47 deforms, and second link 27 rotates relative to first link 25 in a direction that bends the finger, as shown in Figure 4. The rotation of second link 27 relative to first link 25 is transmitted to third link 29 by 3Y link mechanism 49, and third link 29 rotates relative to second link 27 in a direction that bends the finger.

[0057] When 2Y drive source 69 stops applying tension to 2Y wire 71 (for example, stops driving), the biasing force of return mechanism 72 causes 2Y driven pulley 45 to rotate in the opposite direction and return to its original position. This causes second link 27 to rotate in the direction in which the finger extends (i.e., the negative direction) relative to first link 25. At this time, just as when bending, the rotation of second link 27 relative to first link 25 is transmitted to third link 29 by 3Y link mechanism 49, and third link 29 rotates in the direction in which the finger extends relative to second link 27.

[0058] The control device 57 is configured by a computer equipped with a central processing unit (CPU), memories such as RAM (random access memory) and ROM (read only memory), and storage devices such as SSD (solid state device) and HDD (hard disk drive). The control device 57 is connected to the 1Z drive source 61, the 1Y drive source 65, and the 2Y drive source 69, respectively, and controls the drive of each.

[0059] Next, a method for controlling thumb portion 21A will be described. Control device 57 controls the driving of 1Z driving source 61, 1Y driving source 65, and 2Y driving source 69, thereby controlling thumb portion 21A.

[0060] Specifically, when the control device 57 drives the 1Z drive source 61 to pull the 1Z wire 63, the base member 23 rotates in both directions about the 1Z axis, causing the base of the thumb 21A to rotate in both directions about the 1Z axis relative to the palm 19.

[0061] When control device 57 drives 1Y drive source 65 to pull bent end 67P of 1Y wire 67, first link 25 rotates in a bending direction about the 1Y axis relative to base end member 23. As a result, the base of thumb 21A rotates in a bending direction about the 1Y axis relative to palm 19.

[0062] When control device 57 drives 1Y drive source 65 to pull extended end 67Q of 1Y wire 67, first link 25 rotates in the extending direction about the 1Y axis relative to base end member 23. As a result, the base of thumb 21A rotates in the extending direction about the 1Y axis relative to palm 19.

[0063] When the base of thumb 21A is rotated in the 1Y direction, 1Y drive source 65 is driven, and tension is applied to 1Y wire 67. Since 1Y wire 67 is wound around auxiliary idler pulleys 41A to 41C, torque in the 1Z direction is also applied to base end member 23.

[0064] When it is necessary to rotate the base of thumb 21A only in the 1Y direction and prevent it from rotating in the 1Z direction, control device 57 drives 1Z drive source 61 so as to cancel out the torque generated in base end member 23 by 1Y wire 67. Specifically, control device 57 drives 1Z drive source 61 so as to generate a torque in the opposite direction to the torque applied to base end member 23 from 1Y wire 67.

[0065] When control device 57 drives 2Y drive source 69 to pull 2Y wire 71, 2Y wire 71 is pulled, 2Y link mechanism 47 is deformed, and second link 27 rotates relative to first link 25 in a direction that bends thumb portion 21A. At this time, third link 29 also rotates together with second link 27 in a direction that bends thumb portion 21A. As a result, the 2Y joint corresponding to the connection portion of first link 25 and second link 27 and the 3Y joint corresponding to the connection portion of second link 27 and third link 29 bend, and thumb portion 21A bends.

[0066] When control device 57 controls 2Y drive source 69 to stop applying tension to 2Y wire 71, 2Y link mechanism 47 deforms, and second link 27 rotates relative to first link 25 in the direction in which the finger extends. At this time, third link 29 also rotates in the direction in which the finger extends together with second link 27. As a result, the 2Y joint corresponding to the connection portion between first link 25 and second link 27 and the 3Y joint corresponding to the connection portion between second link 27 and third link 29 extend, and thumb 21A extends.

[0067] In this way, by the control device 57 controlling each of the 1Z drive source 61, the 1Y drive source 65, and the 2Y drive source 69, the thumb portion 21A can be rotated at its base on two axes (1Z, 1Y) relative to the palm portion 19, and the thumb portion 21A can be flexed and extended at the 2Y joint and the 3Y joint.

[0068] Next, the effects of the thumb portion 21A configured in this manner and the method for controlling the thumb portion 21A will be described.

[0069] A 1Z wire 63 is wound around the 1Z driven pulley 33 and connected to a 1Z driving source 61. A 1Y wire 67 is wound around the first and third idler pulleys 39C and connected to a 1Y driving source 65. The 1Z driven pulley 33 and the first and third idler pulleys 39C are arranged coaxially.

[0070] This allows the direction in which 1Z wire 63 is pulled out from 1Z driven pulley 33 (the direction in which it is connected to the corresponding drive source) to be roughly aligned with the direction in which 1Y wire 67 is pulled out from first idler pulley 39A, making it possible to arrange the two wires compactly. Furthermore, because 2Y wire 71 is also pulled out via second idler pulley 39B, the direction in which 2Y wire 71 is pulled out can also be aligned with the direction in which 1Z wire 63 and 1Y wire 67 are pulled out. This allows the three wires to be arranged compactly.

[0071] The palm portion 19 is connected to the lower arm portion 15 via a wrist joint. The wrist joint portion is required to be thinner than the lower arm portion 15 and the palm portion 19 so as not to hinder the rotation of the palm portion 19. According to the present invention, the wires can be pulled out in the same direction, and by directing the pull-out direction toward the wrist joint portion, the wires that drive the thumb portion 21A can be easily laid in the wrist joint portion. Furthermore, even if the wires are configured as control cables with an outer tube and an inner wire, the wires can be laid in a straight line, making it less likely to hinder joint movement.

[0072] In humanoid robots, it is often assumed that all of the joints of thumb 21A are bent to grasp an object. In robot 3 according to the present invention, when all of the joints of thumb 21A are bent, control device 57 drives 1Y drive source 65 to pull bent end 67P of 1Y wire 67, thereby rotating first link 25 in a direction to bend relative to base end member 23. At the same time, control device 57 drives 2Y drive source 69 to pull 2Y wire 71, thereby rotating second link 27 in a direction to bend relative to first link 25.

[0073] As shown in Fig. 7, when bent end 67P is pulled by 1Y driving source 65, a torque (see solid arrow Ta in Fig. 7) is applied to base end member 23 to rotate it counterclockwise as viewed from the positive side of the Z direction. When 2Y wire 71 is pulled by 2Y driving source 69, a torque (see dashed arrow Tb in Fig. 7) is applied to base end member 23 to rotate it clockwise as viewed from the positive side of the Z direction. In this way, auxiliary idler pulleys 41A to 41E (more specifically, auxiliary idler pulleys 41A and 41D) are arranged so that the torque about the 1Z axis applied to base end member 23 when 1Y driving source 65 is driven to bend the 1Y axis and the torque about the 1Z axis applied to base end member 23 when 2Y driving source 69 is driven to bend the 2Y axis cancel each other out.

[0074] 7, the winding direction of 1Y bending side wire 67A around first idler pulley 39A (right-handed, also called clockwise when viewed from the positive side of the Z direction; see solid arrow Ra in FIG. 7) is opposite to the winding direction of 2Y wire 71 around second idler pulley 39B from 2Y driving source 69 (left-handed, also called counterclockwise when viewed from the positive side of the Z direction; see dashed arrow Rb in FIG. 7). Here, the winding direction refers to the winding direction (winding direction) of 1Y bending side wire 67A and 2Y wire 71 around the corresponding idler pulley 39 when traced from the driving sources (1Y driving source 65 and 2Y driving source 69).

[0075] That is, in order to rotate the first link 25 in a predetermined direction (bending direction) relative to the base end member 23, the winding direction of the 1Y wire 67 (1Y bending side wire 67A) around the first idler pulley 39A when traced from the end (bending end 67P) pulled by the 1Y drive source 65 is opposite to the winding direction of the 2Y wire 71 around the second idler pulley 39B when traced from the end pulled by the 2Y drive source 69.

[0076] Due to the arrangement of auxiliary idler pulleys 41A-41E, when 1Y drive source 65 and 2Y drive source 69 are driven to bend the 1Y joint and the 2Y joint in the respective bending directions (i.e., in the same direction), the torques about the 1Z axis applied to base end member 23 are reversed and canceled out. This makes it possible to reduce the torque about the 1Z axis applied to base end member 23, thereby preventing rotation of thumb 21A about the 1Z axis due to bending of the 1Y joint and the 2Y joint.

[0077] When the base of the thumb 21A is rotated only about the 1Y axis, the control device 57 drives the 1Z drive source 61 so as to cancel out the torque generated in the base end member 23. This prevents torque from being generated in the base end member 23 by the drive of the 1Z drive source 61 when only the first link 25 is rotated, so that rotation of the thumb 21A relative to the palm 19 can be more reliably prevented.

[0078] The two-axis joint (1Z joint, 1Y joint) between the base of the thumb 21A and the palm 19 is driven in both directions by a 1Z drive source 61 and a 1Y drive source 65. On the other hand, the joints (2Y joint, 3Y joint) that are further from the base side are rotated in only one direction by a 2Y wire 71 and are returned in the opposite direction by a biasing mechanism 72. In this way, by driving the joints in one direction and returning them by a biasing mechanism 72, the number of wires required for drive can be reduced.

[0079] Although the description of the specific embodiment has been completed above, the present invention is not limited to the above embodiment and can be widely modified and implemented. Furthermore, the specific configuration, arrangement, quantity, and predetermined procedure of each member and part can be appropriately changed without departing from the spirit of the present invention. Meanwhile, not all of the components shown in the above embodiment are necessarily required, and can be selected as appropriate.

[0080] In the above embodiment, the end effector (thumb portion 21A) is provided with four auxiliary idler pulleys 41, but the present invention is not limited to the number of auxiliary idler pulleys 41. The end effector may be provided with three auxiliary idler pulleys 41, or may be provided with five or more auxiliary idler pulleys 41.

[0081] In the above embodiment, the torques applied from 1Y wire 67 and 2Y wire 71 are configured to be in opposite directions when the 1Y joint and the 2Y joint are bent, respectively. Even in the case of three or more joints, if torque is generated in base end member 23 by pulling the wires for driving each joint, the torque generated in base end member 23 can be canceled out by adjusting the position of auxiliary idler pulley 41. In this case, for example, the position of auxiliary idler pulley 41 can be adjusted so that the wire is wound in the opposite direction around corresponding idler pulley 39 arranged coaxially with the 1Z axis. [Explanation of symbols]

[0082] 19: Palm (base) 21A: Thumb (end effector) 23: Base end member (first member) 25: First link (second member) 27: Second link (third member) 33: 1Z driven pulley (first driven pulley) 39A: 1st idler pulley 39B: Second idler pulley 39C: 3rd idler pulley 41: Auxiliary idler pulley (auxiliary idler member) 43: 1Y driven pulley (second driven pulley) 45: 2Y driven pulley (third driven pulley) 61: 1Z drive source (first drive source) 63: 1Z wire (first wire) 65:1Y drive source (second drive source) 67: 1Y wire (second wire) 69: 2Y drive source (third drive source) 71: 2Y wire (third wire)

Claims

1. An end effector, a first member rotatably connected to the base about a first axis; a first driven pulley fixed to the first member coaxially with respect to the first shaft; a first wire wound around the first driven pulley and pulled by a first driving source to rotate the first member about the first axis relative to the base; a second member connected to the first member so as to be rotatable about a second axis extending in a direction different from the first axis; a second driven pulley fixed to the second member coaxially with respect to the second shaft; a second wire wound around the second driven pulley and pulled by a second drive source to rotate the second member around the second axis relative to the first member; a third member rotatably connected to the second member about a third axis; a third driven pulley that rotates the third member about the third shaft; a third wire wound around the third driven pulley and pulled by a third driving source to rotate the third member around the second shaft; a first idler pulley is provided that is coaxial with the first shaft and rotatably supported on the first member; the second wire is wound around the first idler pulley between the second driving source and the second driven pulley, a second idler pulley is provided that is coaxial with the first shaft and rotatably supported with respect to the first member; the third wire is wound around the second idler pulley between the third driving source and the third driven pulley, the second axis and the third axis are parallel to each other, An end effector in which the second wire and the third wire are each arranged around the first axis so that when the second member is rotated in the same direction relative to the first member and the third member is rotated in the same direction relative to the second member, the torque applied to the first member from the second driving source via the second wire and the torque applied to the first member from the third driving source via the third wire are in opposite directions.

2. The end effector according to claim 1 , wherein the second wire is wound around the first idler pulley in a direction opposite to the direction in which the third wire is wound around the second idler pulley.

3. An end effector as described in claim 1 or claim 2, wherein the first member is provided with a plurality of auxiliary idler members around which the second wire and the third wire are wound.

4. the first driven pulley is connected to the first drive source via the first wire so as to be rotatably driven in both directions; the second driven pulley is connected to the second drive source via the second wire so as to be rotatable in both directions; the third driven pulley is connected to the third drive source by the third wire so as to be rotatable in one direction; 4. The end effector according to claim 1, wherein the third driven pulley is biased against the direction of pulling by the third wire.

5. a third idler pulley is provided that is coaxial with the first idler pulley and rotatably supported by the first member; 5. The end effector according to claim 1, wherein the second wire is wound around the first idler pulley, the second driven pulley, and the third idler pulley in this order.

6. A method for driving an end effector for driving the end effector according to any one of claims 1 to 5, comprising: A method for driving an end effector, wherein when rotating only the second member, the first driving source is driven so as to cancel out torque generated in the first driven pulley by driving the second driving source.

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