Link actuator and origin positioning method

Abstract

To provide a link operation device that can suppress interference with an end effector when positioning an original point of a tip link hub.SOLUTION: A link operation device includes a spherical surface link mechanism and an original point positioning member. The spherical surface link mechanism includes: a proximal link hub; a distal link hub; a plurality of links; and a plurality of intermediate link hubs. Each of the links includes: a first end link member, a second end link member and an intermediate link member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a link actuator and an origin positioning method. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2014-119069 (Patent Document 1) describes a link actuation device. The link actuation device described in Patent Document 1 has a spherical link mechanism and an origin positioning member. The spherical link mechanism has a base end link hub, a tip end link hub, and a plurality of links. Each of the plurality of links has a first end link member, a second end link member, and an intermediate link member.

[0003] The first end link member is connected at one end to the base end link hub rotatably about a first rotation axis. The second end link member is connected at one end to the tip end link hub rotatably about a second rotation axis. The intermediate link member is connected at one end of the intermediate link member to the other end of the first end link member about a third rotation axis, and at the other end of the intermediate link member to the other end of the second end link member rotatably about a fourth rotation axis.

[0004] The first and third rotating shafts and the central axis (first central axis) of the base link hub intersect at the center point of the first spherical link. The second and fourth rotating shafts and the central axis (second central axis) of the tip link hub intersect at the center point of the second spherical link. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-119069 A Summary of the Invention [Problem to be solved by the invention]

[0006] A first through hole is formed in the center of the base link hub, penetrating the base link hub along the direction of the first central axis. A second through hole is formed in the center of the tip link hub, penetrating the tip link hub along the direction of the second central axis. In the link actuation device described in Patent Document 1, the origin position of the tip link hub is positioned by inserting an origin positioning member into the first through hole and the second through hole.

[0007] However, an end effector is attached to the center of the tip link hub, and therefore, when an attempt is made to position the tip link hub at its origin by inserting an origin positioning member into the first and second through holes, the origin positioning member may interfere with the end effector.

[0008] The present invention has been made in consideration of the above-mentioned problems of the conventional technology. More specifically, the present invention provides a link actuator and an origin positioning method that can suppress interference with an end effector when positioning the origin of a tip link hub. [Means for solving the problem]

[0009] A link actuation device according to a first aspect of the present invention includes a spherical link mechanism and an origin positioning member. The spherical link mechanism includes a base end link hub, a tip end link hub, a plurality of links, and a plurality of intermediate link hubs. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member. The first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable around a first rotation axis. The second end link member is connected to the tip end link hub at one end of the second end link member so as to be rotatable around a second rotation axis. The intermediate link member is connected to the other end of the first end link member at one end of the intermediate link member so as to be rotatable around a third rotation axis, and is connected to the other end of the second end link member at the other end of the intermediate link hub so as to be rotatable around a fourth rotation axis. The first central axis, which is the central axis of the base end link hub, the first rotation axis, and the third rotation axis intersect at the first spherical link center point. The second central axis, which is the central axis of the tip link hub, the second rotation axis, and the fourth rotation axis intersect at the second spherical link center point. Each of the multiple intermediate link hubs is connected to the intermediate link member of each of the multiple links. Each of the multiple intermediate link hubs is connected to one another rotatably about a fifth rotation axis passing through the first spherical link center point and the second spherical link center point. The origin positioning member prevents two or more of the multiple intermediate link hubs from rotating relative to one another about the fifth rotation axis when the tip link hub is in the origin position.

[0010] In the above link actuation device, each of the multiple intermediate link hubs may include a connecting portion and a beam portion. The beam portion may be connected to the connecting portion at one end of the beam portion and to the intermediate link member at the other end of the beam portion. A first through hole may be formed in the center of the connecting portion, penetrating the connecting portion along the direction of the fifth rotation axis. The connecting portions of each of the multiple intermediate link hubs may be connected to each other rotatably around the fifth rotation axis such that the first through holes overlap with each other. The origin positioning member may be inserted into the first through hole of each of the multiple intermediate link hubs when the tip link hub is in the origin position.

[0011] In the above link actuation device, each of the multiple intermediate link hubs may include a connecting portion and a beam portion. The beam portion may be connected to the connecting portion at one end of the beam portion and to the intermediate link member at the other end of the beam portion. A second through hole may be formed at a position offset from the center of the connecting portion, penetrating the connecting portion along the direction of the fifth rotation axis. The connecting portions of each of the multiple intermediate link hubs may be connected to each other rotatably around the fifth rotation axis such that the second through holes overlap with each other when the tip link hub is in the origin position. The origin positioning member may be inserted into the second through hole of each of the multiple intermediate link hubs when the tip link hub is in the origin position.

[0012] In the above link actuation device, the base link hub may be formed with a third through hole penetrating the base link hub along the direction of the first central axis. The tip link hub may be formed with a fourth through hole penetrating the tip link hub along the direction of the second central axis. The second through hole, the third through hole and the fourth through hole of each of the multiple intermediate link hubs may be positioned to overlap with each other when the tip link hub is in the home position. The home positioning member may be inserted into the second through hole, the third through hole and the fourth through hole of each of the multiple intermediate link hubs when the tip link hub is in the home position.

[0013] In the above link actuation device, the connecting portion of each of the plurality of intermediate link hubs may be disposed outside the plurality of links. In the above link actuation device, the second through hole may be a slit formed in an outer circumferential surface of the connecting portion.

[0014] In the above link actuation device, the origin positioning member may be detachable from the spherical link mechanism. In the above link actuation device, the origin positioning member may be held by the spherical link mechanism.

[0015] A link actuation device according to a second aspect of the present invention includes a spherical link mechanism, a light source, and a detector that receives light from the light source. The spherical link mechanism includes a base end link hub, a tip end link hub, a plurality of links, and a plurality of intermediate link hubs. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member. The first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable around a first rotation axis. The second end link member is connected to the tip link hub at one end of the second end link member so as to be rotatable around a second rotation axis. The intermediate link member is connected to the other end of the first end link member so as to be rotatable around a third rotation axis at one end of the intermediate link member, and is connected to the other end of the second end link member around a fourth rotation axis at the other end of the intermediate link member. The first central axis, which is the central axis of the base end link hub, the first rotation axis, and the third rotation axis intersect at the center point of the first spherical link. The second central axis, which is the central axis of the tip link hub, the second rotation axis, and the fourth rotation axis intersect at the second spherical link center point. Each of the multiple intermediate link hubs is connected to the intermediate link member of each of the multiple links. Each of the multiple intermediate link hubs is rotatably connected to each other about a fifth rotation axis passing through the first spherical link center point and the second spherical link center point. Each of the multiple intermediate link hubs includes a connecting portion and a beam portion. The beam portion is connected to the connecting portion at one end of the beam portion and to the intermediate link member at the other end of the beam portion. A second through hole is formed at a position shifted from the center of the connecting portion, penetrating the connecting portion along the direction of the fifth rotation axis. The connecting portions of each of the multiple intermediate link hubs are connected to each other so that the second through holes overlap each other when the tip link hub is at the origin position, and are rotatably connected to each other about the fifth rotation axis. The base link hub is formed with a third through hole penetrating the base link hub along the direction of the first central axis. The tip link hub has a fourth through hole formed therein that passes through the tip link hub along the direction of the second central axis. The second through hole, the third through hole and the fourth through hole of each of the multiple intermediate link hubs are positioned to overlap with each other when the tip link hub is in the origin position.When the end link hub is in the home position, light from the light source passes through the second through hole, the third through hole and the fourth through hole of each of the plurality of intermediate link hubs and is received by the detector.

[0016] An origin positioning method according to one aspect of the present invention includes a step of preparing a link actuation device having a spherical link mechanism, an origin positioning member, and a drive source. The spherical link mechanism includes a base end link hub, a tip end link hub, a plurality of links, and a plurality of intermediate link hubs. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member. The first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable around a first rotation axis. The second end link member is connected to the tip end link hub at one end of the second end link member so as to be rotatable around a second rotation axis. The intermediate link member is connected to the other end of the first end link member so as to be rotatable around a third rotation axis at one end of the intermediate link member, and is connected to the other end of the second end link member around a fourth rotation axis at the other end of the intermediate link member. The first central axis, which is the central axis of the base link hub, the first rotation axis, and the third rotation axis intersect at the center point of the first spherical link. The second central axis, which is the central axis of the tip link hub, the second rotation axis, and the fourth rotation axis intersect at the center point of the second spherical link. Each of the multiple intermediate link hubs is connected to the intermediate link member of each of the multiple links. Each of the multiple intermediate link hubs is connected to each other rotatably about a fifth rotation axis passing through the center point of the first spherical link and the center point of the second spherical link. The origin positioning method further includes a step of making two or more of the multiple intermediate link hubs unable to rotate relative to each other about the fifth rotation axis by the origin positioning member when the tip link hub is in the origin position, a step of applying a preload to each of the multiple links by the drive source, and a step of outputting or recording at least one of the position of each of the multiple links, the torque applied to each of the multiple links from the drive source, and the operation amount of the drive source in a state in which the multiple links are preloaded. Effect of the Invention

[0017] According to the link actuation device of the first aspect of the present invention, the link actuation device of the second aspect of the present invention, and the origin positioning method of one aspect of the present invention, it is possible to suppress interference with the end effector when positioning the tip link hub at the origin. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a perspective view of the link actuator 100. [Diagram 2] FIG. 2 is a front view of the link actuator 100. [Diagram 3] FIG. 2 is a side view of the link actuator 100. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 2 is a plan view of the link actuator 100. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] 10 is a process diagram showing an origin positioning method in the link actuator 100. FIG. [Figure 8] FIG. 2 is a perspective view of a link actuator 100A. [Figure 9] FIG. 2 is a front view of the link actuator 100A. [Figure 10] 10 is a cross-sectional view taken along line XX in FIG. 9. [Figure 11] FIG. 2 is a plan view of the link actuator 100A. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 2 is a perspective view of a link actuator 100B. [Figure 14] FIG. 11 is a front view of the link actuator 100B. [Figure 15] FIG. 11 is a plan view of the link actuator 100B. [Figure 16] 16 is a cross-sectional view taken along line XVI-XVI in FIG. 14. [Figure 17] FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. [Figure 18] FIG. 2 is a perspective view of a link actuator 100C. [Figure 19] FIG. 2 is a front view of the link actuator 100C. [Figure 20] FIG. 2 is a side view of the link actuator 100C. [Figure 21] FIG. 20 is a cross-sectional view taken along line XXI-XXI in FIG. 19. [Figure 22] FIG. 22 is a cross-sectional view taken along line XXII-XXII in FIG. 20. [Figure 23] FIG. 23 is an enlarged view of region XXIII in FIG. 22. [Figure 24] FIG. 13 is a perspective view of a link actuator 100D. [Diagram 25] FIG. 13 is a plan view of the link actuator 100D. [Figure 26] 26 is a cross-sectional view taken along line XXVI-XXVI of FIG. 25. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and redundant description will not be repeated.

[0020] (First embodiment) A link actuating device according to a first embodiment (hereinafter referred to as a "link actuating device 100") will be described.

[0021] <General Configuration of Link Actuator 100> FIG 1 is a perspective view of the link actuator 100. FIG 2 is a front view of the link actuator 100. FIG 3 is a side view of the link actuator 100. FIG 4 is a cross-sectional view taken along line IV-IV in FIG 3. FIG 5 is a plan view of the link actuator 100. FIG 6 is a cross-sectional view taken along line VI-VI in FIG 5.

[0022] As shown in FIGS. 1 to 6, the link actuation device 100 has a spherical link mechanism 10, an origin positioning member 20, and a drive source 30. As shown in FIG.

[0023] <Detailed configuration of the spherical link mechanism 10> The spherical link mechanism 10 has a base end link hub 11, a tip end link hub 12, a plurality of links 13, and a plurality of intermediate link hubs 14.

[0024] The base end link hub 11 and the tip end link hub 12 are, for example, flat. However, the shapes of the base end link hub 11 and the tip end link hub 12 are not limited to this. In the following, the central axis of the base end link hub 11 is referred to as a first central axis, and the central axis of the tip end link hub 12 is referred to as a second central axis. Although not shown, for example, an end effector is attached to the tip end link hub 12.

[0025] The number of the links 13 is, for example, three. However, the number of the links 13 may be four or more. The links 13 are arranged, for example, at equal intervals in a direction along a circumference centered on the first central axis. The link 13 has a first end link member 13a, a second end link member 13b, and an intermediate link member 13c.

[0026] The first end link member 13a is connected at one end thereof to the base end link hub 11 so as to be rotatable about a first rotation axis. The second end link member 13b is connected at one end thereof to the tip end link hub 12 so as to be rotatable about a second rotation axis. The first end link member 13a and the second end link member 13b are, for example, L-shaped.

[0027] The intermediate link member 13c is connected at one end thereof to the other end of the first end link member 13a so as to be rotatable about a third rotation axis. The intermediate link member 13c is connected at the other end thereof to the other end of the second end link member 13b so as to be rotatable about a fourth rotation axis. The intermediate link member 13c is, for example, L-shaped.

[0028] The first rotation axis, the third rotation axis, and the first central axis intersect at the center point of the first spherical link. The second rotation axis, the fourth rotation axis, and the second central axis intersect at the center point of the second spherical link. Therefore, the base end link hub 11 moves on a spherical surface (first moving spherical surface) centered on the center point of the first spherical link, and the tip end link hub 12 moves on a spherical surface (second moving spherical surface) centered on the center point of the second spherical link. In other words, the spherical link mechanism 10 has a structure in which two spherical link mechanisms are combined.

[0029] The number of the intermediate link hubs 14 is equal to the number of the links 13. The intermediate link hub 14 has a connecting portion 14a and a beam portion 14b. The connecting portion 14a is disposed inside the links 13.

[0030] The connecting portions 14a of the multiple intermediate link hubs 14 are connected to each other so as to be rotatable around a fifth rotation axis. The fifth rotation axis passes through both the center point of the first spherical link and the center point of the second spherical link. From another perspective, the fifth rotation axis passes through the center of the plane (a circular intermediate plane) where the first moving spherical surface and the second moving spherical surface intersect, and is perpendicular to the intermediate plane. This is always true regardless of the positions and postures of the base end link hub 11 and the tip end link hub 12. Therefore, the spherical link mechanism 10 can operate in the same way as when it does not have multiple intermediate link hubs 14.

[0031] A first through hole 14aa is formed in the connecting portion 14a. The first through hole 14aa penetrates the connecting portion 14a along the direction of the fifth rotation axis. The first through holes 14aa of the multiple intermediate link hubs 14 overlap each other.

[0032] A first groove 14ab and a second groove 14ac are formed on the inner wall surface of the first through hole 14aa. The first groove 14ab and the second groove 14ac extend from the inner wall surface of the first through hole 14aa toward the outside in the radial direction of the first through hole 14aa. The first groove 14ab and the second groove 14ac are located symmetrically with respect to the center of the first through hole 14aa.

[0033] The first groove 14ab and the second groove 14ac of each of the multiple intermediate link hubs 14 are formed to overlap with each other when the tip link hub 12 is in the origin position. The tip link hub 12 is in the origin position when the second central axis is on the same straight line as the first central axis (when the bending angle of the spherical link mechanism 10 is 0°).

[0034] One end of the beam portion 14b is connected to the connecting portion 14a. The other end of the beam portion 14b is connected to the intermediate link member 13c. The intermediate link hub 14 (connecting portion 14a and beam portion 14b) may be integrally formed with the intermediate link member 13c.

[0035] <Detailed configuration of origin positioning member 20> The origin positioning member 20 is plate-shaped. The origin positioning member 20 has a first end 20a and a second end 20b. The first end 20a and the second end 20b are ends in the longitudinal direction of the origin positioning member 20. The second end 20b is an end opposite to the first end 20a.

[0036] The origin positioning member 20 has a first portion 21 and a second portion 22. The first portion 21 is a portion on the first end 20a side of the origin positioning member 20, and the second portion 22 is a portion on the second end 20b side of the origin positioning member 20. The width of the first portion 21 in a direction perpendicular to the longitudinal direction of the origin positioning member 20 is larger than the width of the second portion 22 in a direction perpendicular to the longitudinal direction of the origin positioning member 20. The width of the first portion 21 in the direction perpendicular to the longitudinal direction of the origin positioning member 20 decreases toward the first end 20a.

[0037] The origin positioning member 20 is inserted into the first through hole 14aa (more specifically, the first groove 14ab and the second groove 14ac) of each of the multiple intermediate link hubs 14 when the end link hub 12 is in the origin position, thereby preventing the multiple intermediate link hubs 14 from rotating relative to each other around the fifth rotation axis.

[0038] When the multiple intermediate link hubs 14 become unable to rotate relative to each other around the fifth rotation axis, the positions and attitudes of the base end link hub 11, the tip link hub 12 and the multiple links 13 are fixed, thereby fixing the tip link hub 12 at the origin position. Note that it is sufficient for the origin positioning member 20 to make at least two or more of the multiple intermediate link hubs 14 unable to rotate around the fifth rotation axis.

[0039] <Detailed configuration of driving source 30> The driving source 30 is, for example, a motor. The number of the driving sources 30 is equal to the number of the links 13, for example. However, the number of the driving sources 30 may be less than the number of the links 13 as long as it is two or more. Each of the driving sources 30 rotates the first end link member 13a of each of the links 13 about a first rotation axis. By changing the amount of rotation, the position and posture of the tip link hub 12 are changed.

[0040] <Origin positioning method in link actuator 100> Fig. 7 is a process diagram showing an origin positioning method in the link actuating device 100. As shown in Fig. 7, the origin positioning method in the link actuating device 100 has a preparation step S1, an origin positioning member inserting step S2, a preload step S3, and a recording step S4. The origin positioning member inserting step S2 is performed after the preparation step S1. The preload step S3 is performed after the origin positioning member inserting step S2. The recording step S4 is performed after the preload step S3.

[0041] In the preparation step S1, the link actuation device 100 is prepared. In the origin positioning member insertion step S2, first, the driving source 30 adjusts the amount by which the first end link member 13a is rotated about the first rotation axis, thereby moving the tip link hub 12 to the origin position. Second, in the origin positioning member insertion step S2, the origin positioning member 20 is inserted into the first through hole 14aa (the first groove 14ab and the second groove 14ac) of each of the multiple intermediate link hubs 14. This makes the multiple intermediate link hubs 14 unable to rotate about the fifth rotation axis, and the tip link hub 12 is fixed to the origin position.

[0042] In the preloading step S3, each of the multiple driving sources 30 generates a torque that rotates the first end link member 13a of each of the multiple links 13 about the first rotation axis, thereby applying a preload to each of the multiple links 13. In the recording step S4, the torque of each of the multiple driving sources 30 in the above-mentioned preloading state is recorded or output.

[0043] In the recording step S4, instead of the torque of each of the multiple drive sources 30, the amount of movement of each of the multiple drive sources 30 may be recorded or output, and the position of each of the multiple links 13 may be recorded or output. The torque of each of the multiple drive sources 30 recorded or output at this time (the amount of movement of each of the multiple drive sources 30, the position of each of the multiple links 13) is reflected in the output of each of the multiple drive sources 30 during operation of the link actuation device 100. This makes it possible to suppress rattling of each rotation pair during operation of the link actuation device 100.

[0044] <Effects of the link actuator 100> In the link actuating device 100, the tip link hub 12 can be positioned at its origin by inserting the origin positioning member 20 into the first through holes 14aa of the multiple intermediate link hubs 14. Therefore, in the link actuating device 100, when positioning the tip link hub 12 at its origin, interference between the origin positioning member 20 and the end effector attached to the tip link hub 12 is suppressed.

[0045] Second embodiment A link actuation device according to a second embodiment (hereinafter, referred to as "link actuation device 100A") will be described. Here, differences from the link actuation device 100 will be mainly described, and overlapping descriptions will not be repeated.

[0046] Fig. 8 is a perspective view of the link actuating device 100A. Fig. 9 is a front view of the link actuating device 100A. Fig. 10 is a cross-sectional view taken along line XX in Fig. 9. Fig. 11 is a plan view of the link actuating device 100A. Fig. 12 is a cross-sectional view taken along line XII-XII in Fig. 11. Note that the driving source 30 is omitted from Figs. 8 to 12. As shown in Figs. 8 to 12, in the link actuating device 100A, a second through hole 14ad is formed in each of the connecting portions 14a of the multiple intermediate link hubs 14.

[0047] The second through hole 14ad penetrates the connecting portion 14a along the direction of the fifth rotation axis. The second through hole 14ad is located at a position offset from the center of the connecting portion 14a. The second through holes 14ad of each of the multiple intermediate link hubs 14 are formed to overlap with each other when the tip link hub 12 is in the origin position.

[0048] In the link actuation device 100A, when the tip link hub 12 is at the origin position, the origin positioning member 20 is inserted into the second through hole 14ad of each of the multiple intermediate link hubs 14. This makes the multiple intermediate link hubs 14 unable to rotate relative to each other around the fifth rotation axis. In the link actuation device 100A, the origin positioning member 20 is rod-shaped.

[0049] In the link actuation device 100A, a third through hole 11a is formed in the base end link hub 11, and a fourth through hole 12a is formed in the tip end link hub 12. The third through hole 11a is formed at a position offset from the center of the base end link hub 11. The fourth through hole 12a is at a position offset from the center of the tip end link hub 12. When the tip end link hub 12 is in the origin position, the third through hole 11a and the fourth through hole 12a are in positions overlapping with the second through holes 14ad of each of the multiple intermediate link hubs 14. When the tip end link hub 12 is in the origin position, the origin positioning member 20 is inserted into the third through hole 11a and the fourth through hole 12a in addition to the second through holes 14ad of each of the multiple intermediate link hubs 14.

[0050] In the link actuation device 100A, when the tip link hub 12 is at the origin position, the origin positioning member 20 is inserted into the second through-holes 14ad of the multiple intermediate link hubs 14, thereby preventing the multiple intermediate link hubs 14 from rotating relative to each other around the fifth rotation axis. Therefore, in the link actuation device 100A, when positioning the tip link hub 12 at the origin, the origin positioning member 20 is prevented from interfering with the end effector attached to the tip link hub 12.

[0051] Furthermore, in the link actuation device 100A, when the tip link hub 12 is at the origin position, the origin positioning member 20 is inserted into the third through hole 11a and the fourth through hole 12a in addition to the second through hole 14ad of each of the multiple intermediate link hubs 14. Therefore, in the link actuation device 100A, the origin positioning of the tip link hub 12 by the origin positioning member 20 is performed more securely. In addition, since the fourth through hole 12a is located at a position offset from the center of the tip link hub 12, the origin positioning member 20 is less likely to interfere with the end effector attached to the tip link hub 12 when positioning the tip link hub 12 at the origin.

[0052] Third embodiment A link actuation device according to a third embodiment (hereinafter, referred to as "link actuation device 100B") will be described. Here, differences from link actuation device 100A will be mainly described, and overlapping descriptions will not be repeated.

[0053] FIG. 13 is a perspective view of the link actuating device 100B. FIG. 14 is a front view of the link actuating device 100B. FIG. 15 is a plan view of the link actuating device 100B. FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 14. FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. 15. As shown in FIGS. 13 to 17, in the link actuating device 100B, the connecting portion 14a is disposed on the outside of the multiple links 13. In the link actuating device 100B, the connecting portion 14a is annular.

[0054] In the link actuating device 100B, the second through hole 14ad is formed in a slit shape on the outer circumferential surface of the connecting portion 14a. In the link actuating device 100B, the second through hole 14ad extends from the outer circumferential surface of the connecting portion 14a to the radially inward side of the connecting portion 14a.

[0055] In the link actuation device 100B, the origin positioning member 20 is plate-shaped. In the link actuation device 100B, when the tip link hub 12 is in the origin position, the origin positioning member 20 is inserted into the second through-hole 14ad of each of the multiple intermediate link hubs 14. This makes the multiple intermediate link hubs 14 unable to rotate relative to each other around the fifth rotation axis.

[0056] As described above, in the link actuation device 100B, when the tip link hub 12 is at the origin position, the origin positioning member 20 is inserted into the second through-holes 14ad of the multiple intermediate link hubs 14, thereby preventing the multiple intermediate link hubs 14 from rotating relative to each other around the fifth rotation axis. Also, in the link actuation device 100B, the connecting portions 14a are disposed outside the multiple links 13. Therefore, in the link actuation device 100B, when positioning the tip link hub 12 at the origin, interference of the origin positioning member 20 with the end effector attached to the tip link hub 12 is suppressed.

[0057] (Fourth embodiment) A link actuation device according to a fourth embodiment (hereinafter, referred to as "link actuation device 100C") will be described. Here, differences from the link actuation device 100A will be mainly described, and overlapping descriptions will not be repeated.

[0058] FIG. 18 is a perspective view of the link actuating device 100C. FIG. 19 is a front view of the link actuating device 100C. FIG. 20 is a side view of the link actuating device 100C. FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 19. FIG. 22 is a cross-sectional view taken along line XXII-XXII in FIG. 20. FIG. 23 is an enlarged view of region XXIII in FIG. 22. As shown in FIGS. 18 to 23, in the link actuating device 100C, the spherical link mechanism 10 further has a storage member 15. The storage member 15 is attached to the base end link hub 11.

[0059] In the link actuation device 100C, one of the multiple intermediate link hubs 14 is defined as a first intermediate link hub, and the other of the multiple intermediate link hubs 14 is defined as a second intermediate link hub. In the link actuation device 100C, the connection portion 14a of the first intermediate link hub has a shaft portion 14c. The shaft portion 14c is cylindrical and extends in the direction of the fifth rotation axis.

[0060] The connecting portion 14a of the second intermediate link hub is attached to the shaft portion 14c so as to be rotatable around the shaft portion 14c. As a result, the connecting portions 14a of the multiple intermediate link hubs 14 are rotatable relative to one another around the fifth rotation axis. A rotational resistance reduction member 16 is disposed between the shaft portion 14c and the connecting portion 14a of the second intermediate link hub. As a result, the rotational resistance between the shaft portion 14c and the connecting portion 14a of the second intermediate link hub is reduced. The rotational resistance reduction member 16 is, for example, a rolling bearing or a sliding bearing.

[0061] In the link actuation device 100C, when the tip link hub 12 is in the origin position, the origin positioning member 20 is inserted into the second through hole 14ad. This makes the multiple intermediate link hubs 14 unable to rotate relative to each other around the fifth rotation axis. Note that when the tip link hub 12 is in the origin position, the origin positioning member 20 may be inserted into the shaft portion 14c in addition to the second through hole 14ad.

[0062] In the link actuation device 100C, the origin positioning member 20 may have a grip portion 23. In the link actuation device 100C, when the tip link hub 12 is in the origin position, the grip portion 23 is lifted upward, whereby the origin positioning member 20 is inserted into the second through hole 14ad and the shaft portion 14c.

[0063] In the link actuation device 100C, the origin positioning member 20 is stored in the storage member 15. That is, in the link actuation device 100C, the origin positioning member 20 is held by the spherical link mechanism 10. However, the portion of the origin positioning member 20 that is inserted into the second through hole 14ad and the shaft portion 14c, and the grip portion 23 are located outside the storage member 15.

[0064] As described above, in the link actuation device 100C, when the tip link hub 12 is in the origin position, the origin positioning member 20 is inserted into the second through-holes 14ad of the multiple intermediate link hubs 14, thereby preventing the multiple intermediate link hubs 14 from rotating relative to each other around the fifth rotation axis. Therefore, in the link actuation device 100B, when positioning the tip link hub 12 at the origin, the origin positioning member 20 is prevented from interfering with the end effector attached to the tip link hub 12.

[0065] Furthermore, in the link actuation device 100C, the origin positioning member 20 is held by the spherical link mechanism 10 (storage member 15). Therefore, in the link actuation device 100C, the origin positioning member 20 is prevented from being lost or dropped.

[0066] Fifth embodiment A link actuation device according to a fifth embodiment (hereinafter, referred to as "link actuation device 100D") will be described. Here, differences from the link actuation device 100A will be mainly described, and overlapping descriptions will not be repeated.

[0067] Fig. 24 is a perspective view of the link actuating device 100D. Fig. 25 is a plan view of the link actuating device 100D. Fig. 26 is a cross-sectional view taken along line XXVI-XXVI of Fig. 25. As shown in Figs. 24 to 26, the link actuating device 100D has a light source 40, a detector 50, and a base 60. However, the link actuating device 100D does not have an origin positioning member 20.

[0068] In the link actuating device 100D, the spherical link mechanism 10 and the detector 50 are disposed on a mount 60. In the link actuating device 100D, the connecting portion 14a is disposed outside the multiple links 13. In the link actuating device 100D, the connecting portion 14a is annular.

[0069] The light source 40 generates light 41. The light source 40 is, for example, a laser oscillator, and the light 41 is laser light. The second through holes 14ad of each of the multiple intermediate link hubs 14 overlap with each other when the end link hub 12 is in the home position. When the end link hub 12 is in the home position, the light 41 passes through the second through holes 14ad of each of the multiple intermediate link hubs 14 and is irradiated to the detector 50. On the other hand, when the end link hub 12 is not in the home position, the light 41 is blocked by the connection portions 14a of each of the multiple intermediate link hubs 14 and is not irradiated to the detector 50.

[0070] When the light 41 is irradiated to the detector 50, the detector 50 outputs a signal indicating that the light 41 is being irradiated. The detector 50 is, for example, a photodiode. Therefore, based on the output signal from the detector 50, it is detected that the tip link hub 12 is at the origin position.

[0071] An encoder 14ae is provided on the connecting portion 14a. When the tip link hub 12 is in the home position, the value of the encoder 14ae is recorded. In addition, by comparing the value of the encoder 14ae when the link actuator 100D is operating with the value of the encoder 14ae recorded when the tip link hub 12 is in the home position, the position of the tip link hub 12 during operation of the link actuator 100D can be determined.

[0072] In the link actuation device 100D, the tip link hub 12 can be positioned at the origin by passing light 41 through the second through holes 14ad of the multiple intermediate link hubs 14. Therefore, in the link actuation device 100, it is not necessary to use the origin positioning member 20 when positioning the tip link hub 12 at the origin, and interference of the origin positioning member 20 with the end effector attached to the tip link hub 12 is suppressed.

[0073] Although the embodiment of the present invention has been described above, the above-mentioned embodiment can be modified in various ways. The scope of the present invention is not limited to the above-mentioned embodiment. The scope of the present invention is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Industrial Applicability]

[0074] The above-described embodiment can be particularly advantageously applied to a link actuator having a spherical link mechanism. [Explanation of symbols]

[0075] 10 spherical link mechanism, 11 base end link hub, 11a third through hole, 12 tip end link hub, 12a fourth through hole, 13 link, 13a first end link member, 13b second end link member, 13c intermediate link member, 14 intermediate link hub, 14a connecting portion, 14aa first through hole, 14ab first groove, 14ad second through hole, 14ae encoder, 14b beam portion, 14c shaft portion, 15 storage member, 16 rotational resistance reduction member, 20 origin positioning member, 20a first end, 20b second end, 21 first portion, 22 second portion, 23 grip portion, 30 driving source, 40 light source, 41 light, 50 detector, 60 stand, 100, 100A, 100B, 100C, 100D link actuator, S1 Preparation process, S2 origin positioning member insertion process, S3 preload process, S4 recording process.

Claims

1. A spherical link mechanism; An origin positioning member, The spherical link mechanism includes a base end link hub, a tip end link hub, a plurality of links, and a plurality of intermediate link hubs. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member; the first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable about a first rotation axis; The second end link member is connected to the tip link hub at one end of the second end link member so as to be rotatable about a second rotation axis, the intermediate link member is connected at one end thereof to the other end of the first end link member so as to be rotatable about a third rotation axis, and is connected at the other end thereof to the other end of the second end link member so as to be rotatable about a fourth rotation axis, a first central axis line, which is a central axis line of the base end link hub, the first rotation axis line, and the third rotation axis line intersect at a first spherical link center point, a second central axis line, which is a central axis line of the tip link hub, the second rotation axis line, and the fourth rotation axis line intersect at a center point of a second spherical link, each of the plurality of intermediate link hubs is connected to the intermediate link member of each of the plurality of links; each of the plurality of intermediate link hubs is rotatably connected to one another about a fifth rotation axis passing through the first spherical link center point and the second spherical link center point; The origin positioning member prevents two or more of the plurality of intermediate link hubs from rotating relative to each other about the fifth rotation axis when the end link hub is in the origin position.

2. Each of the plurality of intermediate link hubs includes a connecting portion and a beam portion, the beam portion is connected to the connecting portion at one end of the beam portion and to the intermediate link member at the other end of the beam portion, a first through hole is formed at a center of the connecting portion, the first through hole penetrating the connecting portion along the direction of the fifth rotation axis; the first through holes of the respective connecting portions of the plurality of intermediate link hubs overlap with each other and are connected to each other rotatably about the fifth rotation axis; The link actuation device according to claim 1 , wherein the origin positioning member is inserted into the first through hole of each of the plurality of intermediate link hubs when the end link hub is in the origin position.

3. Each of the plurality of intermediate link hubs includes a connecting portion and a beam portion, the beam portion is connected to the connecting portion at one end of the beam portion and to the intermediate link member at the other end of the beam portion, a second through hole is formed at a position offset from the center of the connecting portion, the second through hole penetrating the connecting portion along the direction of the fifth rotation axis, the second through holes of the intermediate link hubs overlap with each other when the tip link hub is in an origin position, and the intermediate link hubs are connected to each other so as to be rotatable about the fifth rotation axis; The link actuator according to claim 1 , wherein the home positioning member is inserted into the second through hole of each of the plurality of intermediate link hubs when the end link hub is in the home position.

4. a third through hole is formed in the base end link hub along the direction of the first central axis, A fourth through hole is formed in the tip link hub along the direction of the second central axis, the fourth through hole penetrating the tip link hub, the second through hole, the third through hole, and the fourth through hole of each of the plurality of intermediate link hubs are positioned to overlap with one another when the tip link hub is in an original position; The link actuator according to claim 3 , wherein the origin positioning member is inserted into the second through hole, the third through hole and the fourth through hole of each of the plurality of intermediate link hubs when the end link hub is in the origin position.

5. The link actuator of claim 3 , wherein the connection portion of each of the plurality of intermediate link hubs is disposed on an outer side of the plurality of links.

6. The link actuator according to claim 5 , wherein the second through hole is a slit formed in an outer circumferential surface of the connecting portion.

7. The link actuator according to any one of claims 1 to 6, wherein the origin positioning member is detachable from the spherical link mechanism.

8. The link actuator according to any one of claims 1 to 6, wherein the origin positioning member is held by the spherical link mechanism.

9. A spherical link mechanism; A light source; a detector that receives light from the light source, The spherical link mechanism includes a base end link hub, a tip end link hub, a plurality of links, and a plurality of intermediate link hubs. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member; the first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable about a first rotation axis; The second end link member is connected to the tip link hub at one end of the second end link member so as to be rotatable about a second rotation axis, the intermediate link member is connected at one end thereof to the other end of the first end link member so as to be rotatable about a third rotation axis, and is connected at the other end thereof to the other end of the second end link member so as to be rotatable about a fourth rotation axis, a first central axis line, which is a central axis line of the base end link hub, the first rotation axis line, and the third rotation axis line intersect at a first spherical link center point, a second central axis line, which is a central axis line of the tip link hub, the second rotation axis line, and the fourth rotation axis line intersect at a center point of a second spherical link, each of the plurality of intermediate link hubs is connected to the intermediate link member of each of the plurality of links; each of the plurality of intermediate link hubs is rotatably connected to one another about a fifth rotation axis passing through the first spherical link center point and the second spherical link center point; Each of the plurality of intermediate link hubs includes a connecting portion and a beam portion, the beam portion is connected to the connecting portion at one end of the beam portion and to the intermediate link member at the other end of the beam portion, a second through hole is formed at a position offset from the center of the connecting portion, the second through hole penetrating the connecting portion along the direction of the fifth rotation axis, the second through holes of the intermediate link hubs overlap with each other when the tip link hub is in an origin position, and the intermediate link hubs are connected to each other so as to be rotatable about the fifth rotation axis; a third through hole is formed in the base end link hub along the direction of the first central axis, A fourth through hole is formed in the tip link hub along the direction of the second central axis, the fourth through hole penetrating the tip link hub, the second through hole, the third through hole, and the fourth through hole of each of the plurality of intermediate link hubs are positioned to overlap with one another when the tip link hub is in an original position; A link actuator device, wherein the light passes through the second through hole, the third through hole and the fourth through hole of each of the plurality of intermediate link hubs and is received by the detector when the end link hub is in an origin position.

10. An origin positioning method, comprising: The method includes the steps of: preparing a link actuator having a spherical link mechanism, an origin positioning member, and a drive source; The spherical link mechanism includes a base end link hub, a tip end link hub, a plurality of links, and a plurality of intermediate link hubs. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member; the first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable about a first rotation axis; The second end link member is connected to the tip link hub at one end of the second end link member so as to be rotatable about a second rotation axis, the intermediate link member is connected at one end thereof to the other end of the first end link member so as to be rotatable about a third rotation axis, and is connected at the other end thereof to the other end of the second end link member so as to be rotatable about a fourth rotation axis, a first central axis line, which is a central axis line of the base end link hub, the first rotation axis line, and the third rotation axis line intersect at a first spherical link center point, a second central axis line, which is a central axis line of the tip link hub, the second rotation axis line, and the fourth rotation axis line intersect at a center point of a second spherical link, each of the plurality of intermediate link hubs is connected to the intermediate link member of each of the plurality of links; each of the plurality of intermediate link hubs is rotatably connected to one another about a fifth rotation axis passing through the first spherical link center point and the second spherical link center point; The origin positioning method includes: using the origin positioning member to make two or more of the plurality of intermediate link hubs non-rotatable relative to each other about the fifth rotation axis when the tip link hub is in the origin position; applying a preload to each of the plurality of links by the driving source; and outputting or recording at least one of a position of each of the plurality of links, a torque applied to each of the plurality of links from the driving source, and an amount of movement of the driving source while the preload is applied to the plurality of links.

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