Hand and Robot Systems

Abstract

To easily realize operation by hand.SOLUTION: A hand 100 comprises: a hand body 2 of which a prescribed first reference axis X is defined; a gripping part 3 of which a prescribed second reference axis Y is defines, and which grips a work-piece; and a connection mechanism 4 which connects the gripping part 3 to the hand body 2. The connection mechanism 4 includes at least one of an eccentric mechanism 41 which supports the gripping part 3 so that the second reference axis Y is eccentrically movable with respect to the first reference axis X, and a tilt mechanism 47 which supports the gripping part 3 so that the second reference axis Y is tiltable with respect to the first reference axis X.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The technology disclosed herein relates to a hand and a robot system. [Background technology]

[0002] Hands that grip a workpiece and perform a task have been known for some time. For example, Patent Document 1 discloses a hand that grips a component and inserts the gripped component into a hole in another component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-285747 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned hand operations, the positional accuracy of the hand has a significant impact on the operation. For example, when inserting a part into a hole, if the part and the hole are misaligned, the part insertion operation becomes difficult. Furthermore, if the insertion direction of the part is inclined relative to the axis of the hole, the part insertion operation becomes difficult. This is not limited to part insertion, but also applies to other operations such as picking up a part and placing a part in a predetermined location. Therefore, improving the positional accuracy of the hand is considered. However, improving the positional accuracy of the hand increases the load on sensing and control when controlling the position of the hand.

[0005] The technology disclosed herein has been made in view of the above points, and its purpose is to easily realize work using a hand. [Means for solving the problem]

[0006] The hand disclosed herein comprises a hand body having a predetermined first reference axis defined therein, a gripping portion having a predetermined second reference axis defined therein for gripping a workpiece, and a connecting mechanism for connecting the gripping portion to the hand body, the connecting mechanism including at least one of an eccentric mechanism for supporting the gripping portion so that the second reference axis is eccentric with respect to the first reference axis, and a tilting mechanism for supporting the gripping portion so that the second reference axis is tiltable with respect to the first reference axis.

[0007] The robot system disclosed herein comprises a robot arm, a hand connected to the robot arm, and a control device that controls the robot arm and the hand, wherein the hand has a hand body on which a predetermined first reference axis is defined, a gripping portion on which a predetermined second reference axis is defined and which grips a workpiece, and a connecting mechanism that connects the gripping portion to the hand body, wherein the connecting mechanism includes at least one of an eccentric mechanism that supports the gripping portion so that the second reference axis is eccentric with respect to the first reference axis, and a tilting mechanism that supports the gripping portion so that the second reference axis is tiltable with respect to the first reference axis, and the control device causes the robot arm and the hand to perform an insertion operation of inserting the workpiece gripped by the hand into a predetermined hole. [Effects of the Invention]

[0008] The hand allows for easy hand-operated work.

[0009] According to the robot system, hand-operated work can be easily performed. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a robot system. [Figure 2] FIG. 2 is a perspective view of the hand. [Figure 3] FIG. 3 is a plan view of the hand. [Figure 4] 4 is a cross-sectional view of the hand taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a cross-sectional view of the hand taken along line VV in FIG. [Figure 6] FIG. 6 is a perspective cross-sectional view of the eccentric mechanism. [Figure 7] FIG. 7 is a perspective cross-sectional view of the tilting mechanism. [Figure 8] FIG. 8 is a cross-sectional view of the hand showing a state in which the gripping portion has moved in a second direction relative to the hand body. [Figure 9] FIG. 9 is a cross-sectional view of the hand showing a state in which the gripping portion is rotated around a first rotation axis relative to the hand body. [Figure 10] FIG. 10 is an end view of the hand taken along line XX in FIG. [Figure 11] FIG. 11 is a cross-sectional view of the hand showing a state in which the rectilinear mechanism has advanced the gripping portion in the first reference axis direction. [Figure 12] FIG. 12 is a cross-sectional view of the hand showing a state in which the opening / closing drive mechanism has caused the fingers to open. [Figure 13] FIG. 13 is a block diagram showing a schematic hardware configuration of the control device. [Figure 14] FIG. 14 is a flowchart of the insertion operation. [Figure 15] FIG. 15 is a schematic diagram of the hand when the contact motion is completed, as viewed from the front. [Figure 16] FIG. 16 is a schematic plan view showing the positional relationship between the workpiece and the hole when the contact operation is completed. [Figure 17] FIG. 17 is a schematic diagram of the hand during the release operation as seen from the front. [Figure 18] FIG. 18 is a schematic plan view showing the positional relationship between the workpiece and the hole at the start of the introducing operation. [Figure 19] FIG. 19 is a schematic diagram of the hand when the introduction operation is completed, as viewed from the front. [Figure 20] FIG. 20 is a schematic diagram of the hand seen from the front during the insertion operation. [Figure 21] FIG. 21 is a schematic plan view showing the positional relationship between the workpiece and the hole during the insertion operation. [Figure 22]FIG. 22 is a schematic diagram of the hand when the insertion operation is completed, as viewed from the front. DETAILED DESCRIPTION OF THE INVENTION

[0011] Exemplary embodiments will now be described in detail with reference to the accompanying drawings.

[0012] FIG. 1 is a schematic diagram showing the configuration of a robot system 1000.

[0013] The robot system 1000 includes a robot 110 including a robot arm 120 and a hand 100, and a control device 130 that controls the robot arm 120 and the hand 100. The hand 100 is connected to the robot arm 120 (specifically, to the tip of the robot arm 120). The hand 100 grasps a workpiece and performs various processes. For example, the control device 130 causes the robot arm 120 and the hand 100 to perform an insertion operation in which the workpiece grasped by the hand 100 is inserted into a predetermined hole. Here, inserting the workpiece also includes press-fitting the workpiece into a hole and screwing the workpiece into a screw hole.

[0014] The robot 110 is, for example, an industrial robot. The robot 110 operates, i.e., moves, a hand 100 by means of a robot arm 120. The hand 100 is one of so-called end effectors. The hand 100 grasps a workpiece. Furthermore, the hand 100 re-holds the workpiece and incorporates the workpiece into another workpiece, etc.

[0015] The robot arm 120 includes a plurality of links 121, a plurality of joints 122, and a plurality of motors. Each joint 122 rotatably connects two adjacent links 121. The plurality of motors rotate and drive the plurality of joints 122, respectively. Each motor is, for example, a servo motor.

[0016] Fig. 2 is a perspective view of the hand 100. Fig. 3 is a plan view of the hand 100. Fig. 4 is a cross-sectional view of the hand 100 taken along line IV-IV in Fig. 3. Fig. 5 is a cross-sectional view of the hand 100 taken along line VV in Fig. 3. Note that in each figure, some elements are omitted to make the configuration easier to understand. The same applies to the following figures.

[0017] The hand 100 includes a hand body 2, a gripping unit 3 that grips a workpiece, and a connecting mechanism 4 that connects the gripping unit 3 to the hand body 2. A predetermined first reference axis X is defined in the hand body 2. A predetermined second reference axis Y is defined in the gripping unit 3. The connecting mechanism 4 includes an eccentric mechanism 41 that supports the gripping unit 3 so that the second reference axis Y is eccentric with respect to the first reference axis X, and a tilting mechanism 47 that supports the gripping unit 3 so that the second reference axis Y is tiltable with respect to the first reference axis X.

[0018] The hand 100 can move the workpiece gripped by the gripper 3 in a straight line in the direction of the first reference axis X while rotating the workpiece around the first reference axis X. This allows the hand 100 to, for example, insert the workpiece into a hole or screw it into a screw hole. Hereinafter, the side from which the gripper 3 advances from the hand main body 2 in the direction of the first reference axis X will be simply referred to as the "advance side" or "tip side," and the side from which the gripper 3 retreats toward the hand main body 2 in the direction of the first reference axis X will be simply referred to as the "retreat side" or "main body side."

[0019] The hand 100 further includes a locking mechanism 9 that restricts the operation of the connecting mechanism 4, and a buffering mechanism 10 that absorbs the force acting on the gripper 3 in the direction of the first reference axis X.

[0020] As shown in Figure 2, the hand body 2 is a box-shaped casing. The hand body 2 is roughly rectangular parallelepiped. As shown in Figures 4 and 5, the hand body 2 has an opening / closing drive mechanism 8 that opens and closes the gripper 3, a rotation mechanism 7 that rotates the gripper 3 around the second reference axis Y, and a linear movement mechanism 6 that moves the gripper 3 linearly relative to the hand body 2 in the direction of the first reference axis X.

[0021] -Grip part- 4, the gripping part 3 has a base 31, a plurality of fingers 32 supported by the base 31, and an operating mechanism 33 that opens and closes the plurality of fingers 32. In this example, the gripping part 3 has three fingers 32 as shown in FIG.

[0022] As shown in FIG. 2, the base 31 is generally cylindrical. More specifically, as shown in FIG. 4, the base 31 has a tube 34a, a ceiling 34b, and a bottom 34c. The tube 34a is a generally cylindrical tube extending about the second reference axis Y. The ceiling 34b is provided at one end of the tube 34a in the direction of the second reference axis Y. The ceiling 34b is a generally circular disk centered on the second reference axis Y. An opening is formed in approximately the center of the ceiling 34b. The tube 34a and the ceiling 34b are formed as a single unit. The bottom 34c is attached to the other end of the tube 34a in the direction of the second reference axis Y. The bottom 34c is a generally circular disk centered on the second reference axis Y. The bottom 34c is formed separately from the tube 34a and the ceiling 34b and is attached to the tube 34a.

[0023] The bottom 34c has three slits 34d formed therein, which penetrate the bottom 34c in the thickness direction and extend in the radial direction centered on the second reference axis Y. One slit 34d is shown in Fig. 4. The slits 34d are arranged at equal intervals (i.e., 120-degree intervals) in the circumferential direction centered on the second reference axis Y.

[0024] The finger 32 is supported on the bottom 34c so as to be slidable along the slit 34d. Specifically, the finger 32 has a first end 32a supported on the base 31 and a second end 32b that comes into contact with the workpiece. The first end 32a is disposed inside the base 31 and slidably engaged with the bottom 34c. This allows the finger 32 to be supported on the base 31 so as to be movable in the radial direction about the second reference axis Y. The finger 32 extends from the base 31 substantially parallel to the second reference axis Y.

[0025] The three fingers 32 are arranged at equal intervals (i.e., 120-degree intervals) in the circumferential direction centered on the second reference axis Y. The three fingers 32 open and close by moving away from and toward each other in the radial direction centered on the second reference axis Y. The fingers 32 grip the workpiece at their second ends 32b.

[0026] The operating mechanism 33 has a plurality of links 36 connected to the plurality of fingers 32, a feed screw 37 that extends about the second reference axis Y and rotates around the second reference axis Y, and a block 38 that is threadedly engaged with the feed screw 37 and to which the plurality of links 36 are connected. The operating mechanism 33 is a so-called link mechanism.

[0027] One link 36 is connected to each finger 32. One end of the link 36 is rotatably connected to the finger 32 (specifically, the first end 32a).

[0028] The feed screw 37 and the block 38 form a so-called feed screw mechanism. The feed screw 37 is disposed inside the base 31. The feed screw 37 extends about the second reference axis Y and is supported by the bottom 34c so as to be rotatable about the second reference axis Y.

[0029] A plurality of links 36 are connected to the block 38. More specifically, the ends of the links 36 opposite to the ends connected to the fingers 32 are rotatably connected to the block 38. That is, one end of the link 36 is connected to the fingers 32, and the other end of the link 36 is connected to the block 38. The fingers 32 are disposed in the slits 34d and cannot rotate around the second reference axis Y relative to the base 31. Therefore, the blocks 38 connected to the three fingers 32 via the links 36 are also unable to rotate around the second reference axis Y relative to the base 31.

[0030] When the lead screw 37 rotates, the block 38 moves in the direction of the second reference axis Y. When the block 38 moves in the direction of the second reference axis Y, the link 36 moves in conjunction with the block 38, causing the fingers 32 to move in the radial direction about the second reference axis Y. When the block 38 approaches the bottom 34c, the fingers 32 move outward in the radial direction. On the other hand, when the block 38 moves away from the bottom 34c, the fingers 32 move inward in the radial direction.

[0031] -Connection mechanism- The connecting mechanism 4 connects the base 31 to the hand body 2. As shown in Fig. 4, the connecting mechanism 4 is connected to the rotation mechanism 7 of the hand body 2. In detail, the connecting mechanism 4 includes an eccentric mechanism 41 that supports the gripper 3 eccentrically with respect to the first reference axis X, and a tilt mechanism 47 that supports the gripper 3 tiltably with respect to the first reference axis X. Fig. 6 is a perspective cross-sectional view of the eccentric mechanism 41.

[0032] The eccentric mechanism 41 is connected to the rotation mechanism 7. As will be described in detail later, the rotation mechanism 7 has a rotation shaft 71 whose axis is the first reference axis X. Of the two ends of the rotation shaft 71, a first end 71a, which is the end closer to the connection mechanism 4, is provided with a first disk 71c and a second disk 71d that are flange-shaped and extend in a plane perpendicular to the first reference axis X. The first disk 71c is positioned closer to the tip of the first end 71a than the second disk 71d. The eccentric mechanism 41 is connected to the first end 71a of the rotation shaft 71.

[0033] The eccentric mechanism 41 has an eccentric body 42 connected to the rotary shaft 71 so as to be movable in a direction perpendicular to the first reference axis X. The eccentric body 42 has a substantially cylindrical tube 42a, a substantially disk-shaped ceiling 42b, and a substantially disk-shaped bottom 42c. The eccentric body 42 has a substantially cylindrical box shape as a whole. The tube 42a, the ceiling 42b, and the bottom 42c are arranged coaxially. That is, the tube 42a extends about axis C, and the axes of the ceiling 42b and the bottom 42c also coincide with axis C. An opening is formed in the approximate center of the ceiling 42b. An opening is formed in the approximate center of the bottom 42c. The eccentric body 42 houses the first disk 71c of the rotary shaft 71. That is, the rotary shaft 71 passes through the opening in the ceiling 42b, and the first disk 71c is arranged between the ceiling 42b and the bottom 42c. The first disk 71c is parallel to the ceiling 42b and the bottom 42c. In other words, the axis C is parallel to the first reference axis X. Between the ceiling 42b and the first disk 71c, a plurality of rolling elements 43 are arranged in a circumferential direction about the first reference axis X. Similarly, between the bottom 42c and the first disk 71c, a plurality of rolling elements 43 are arranged in a circumferential direction about the first reference axis X. In this example, the rolling elements 43 are balls. As the plurality of rolling elements 43 roll, the eccentric body 42 can move in a direction perpendicular to the first reference axis X relative to the rotating shaft 71. At this time, the eccentric body 42 moves in a parallel direction in a direction perpendicular to the first reference axis X without changing its posture (i.e., while maintaining the parallelism between the axis C and the first reference axis X). The eccentric body 42 can move in a parallel direction within a range in which the tube 42a contacts the first disk 71c. However, the eccentric body 42 cannot move in the direction of the first reference axis X relative to the rotary shaft 71.

[0034] The gripping unit 3 is connected to the eccentric body 42 via a tilting mechanism 47. Therefore, the gripping unit 3 can also move together with the eccentric body 42 relative to the rotating shaft 71 in a direction perpendicular to the first reference axis X.

[0035] The eccentric mechanism 41 further includes a second joint 45. The second joint 45 couples the rotating shaft 71 to the gripping unit 3. The second joint 45 is a joint that couples two eccentric parallel shafts and transmits rotation between the two eccentric shafts. In this example, the second joint 45 transmits the rotation of the rotating shaft 71 to the gripping unit 3 in a state in which the second reference axis Y is eccentric with respect to the first reference axis X. In this example, the second joint 45 is a so-called Oldham coupling.

[0036] Specifically, as shown in FIG. 6 , the second joint 45 includes a second disk 71d serving as a first hub, an insert 45a, and an eccentric body 42 serving as the second hub. The eccentric body 42, the insert 45a, and the second disk 71d are aligned in this order from the base 31 side in the direction of the first reference axis X. The second disk 71d is integrally formed with the rotating shaft 71 (specifically, the first end 71a). The second disk 71d and the insert 45a are connected to each other so as to be movable in a first direction B1 perpendicular to the first reference axis X. The insert 45a and the eccentric body 42 are connected to each other so as to be movable in a second direction B2 perpendicular to the first reference axis X and perpendicular to the first direction B1. In other words, the eccentric body 42 is configured to be freely movable relative to the second disk 71d within a plane perpendicular to the first reference axis X. At this time, the eccentric body 42 translates in the direction perpendicular to the first reference axis X without changing its posture. However, the eccentric body 42 cannot rotate around the first reference axis X relative to the second disk 71d.

[0037] The rotating shaft 71 penetrates the insert 45a and enters the inside of the eccentric body 42. The second disk 71d rotates integrally with the rotating shaft 71. When the second disk 71d rotates around the first reference axis X, the eccentric body 42 rotates in conjunction with the second disk 71d because the second disk 71d is configured to be unable to rotate with respect to the second disk 71d. At this time, if the axis C of the eccentric body 42 is eccentric with respect to the first reference axis X, the eccentric body 42 rotates while moving relatively in parallel in a direction perpendicular to the first reference axis X, causing the eccentric body 42 to rotate around the axis C while maintaining the positional relationship between the axis C and the first reference axis X. In other words, the rotation around the first reference axis X input to the second disk 71d is output to the eccentric body 42 as rotation around the axis C that is eccentric with respect to the first reference axis X. The gripping portion 3 is connected to the eccentric body 42, so that when the eccentric body 42 rotates, the gripping portion 3 also rotates.

[0038] FIG. 7 is a perspective cross-sectional view of the tilting mechanism 47. The tilting mechanism 47 has a third joint 48. The third joint 48 connects the rotating shaft 71 and the gripping unit 3. The third joint 48 connects two axes that are inclined relative to each other (i.e., two axes having an angle of deviation) and transmits rotation between the two inclined axes. In this example, the third joint 48 transmits the rotation of the rotating shaft 71 to the gripping unit 3 in a state where the second reference axis Y is inclined relative to the first reference axis X. In other words, the tilting mechanism 47 not only connects the gripping unit 3 to the rotating shaft 71 in a tiltable manner, but also transmits the rotation of the rotating shaft 71 to the gripping unit 3 in a state where the second reference axis Y is inclined relative to the first reference axis X. In this example, the third joint 48 connects the rotating shaft 71 and the gripping unit 3 via the eccentric mechanism 41.

[0039] The third joint 48 has a connecting element 48a. The connecting element 48a is generally annular. The connecting element 48a has a first rotation axis D1 and a second rotation axis D2 extending in directions generally perpendicular to each other. In this example, the first rotation axis D1 and the second rotation axis D2 exist in the same plane, and the first rotation axis D1 and the second rotation axis D2 are generally perpendicular to each other. The eccentric body 42 is connected to the connecting element 48a so as to be rotatable around the first rotation axis D1. More specifically, the bottom 42c of the eccentric body 42 is connected to the connecting element 48a. The first rotation axis D1 is perpendicular to the axis C of the eccentric body 42. Furthermore, the base 31 is connected to the connecting element 48a so as to be rotatable around the second rotation axis D2. More specifically, the tube 34a of the base 31 is connected to the connecting element 48a. The second rotation axis D2 is perpendicular to the second reference axis Y of the grip portion 3.

[0040] The connecting element 48a can freely rotate about a first rotation axis D1 relative to the eccentric body 42, and the base 31 can freely rotate about a second rotation axis D2 relative to the connecting element 48a. Therefore, the grip part 3 can freely tilt with respect to the axis C of the eccentric body 42. The third joint 48 is a so-called universal joint, more specifically, a cross-shaft type universal joint.

[0041] The operation of the connecting mechanism 4 configured in this manner will be described.

[0042] First, the operation of the eccentric mechanism 41 will be described. When a force acting on at least one of the hand body 2 and the gripper 3 causes the hand body 2 and the gripper 3 to move relatively in a direction perpendicular to the first reference axis X, the eccentric body 42 moves in a direction perpendicular to the first reference axis X relative to the rotating shaft 71 due to the rolling of the multiple rolling bodies 43. At the same time, the insert 45a moves in a first direction B1 relative to the second disk 71d, and the eccentric body 42, which is the second hub, moves in a second direction B2 relative to the insert 45a. The movement of the eccentric body 42 causes the eccentric body 42 to move relative to the hand body 2 such that the axis C becomes eccentric with respect to the first reference axis X. The gripper 3, which is connected to the eccentric body 42, moves relative to the hand body 2 such that the second reference axis Y becomes eccentric with respect to the first reference axis X.

[0043] 8 is a cross-sectional view of the hand 100 showing a state in which the gripper 3 has moved in the second direction B2 relative to the hand main body 2. The eccentric body 42 moves parallel to the insert 45a in the second direction B2. Accordingly, the gripper 3 connected to the eccentric body 42 also moves parallel to the insert 45a in the second direction B2. As a result, the second reference axis Y of the gripper 3 becomes eccentric with respect to the first reference axis X of the hand main body 2.

[0044] Similarly, the insert 45a can move parallel to the second disk 71d in the first direction B1. Accordingly, the gripping unit 3, which is connected to the second disk 71d via the insert 45a, can also move parallel to the first direction B1 relative to the second disk 71d. Due to the combined occurrence of such parallel movement of the gripping unit 3 in the first direction B1 and in the second direction B2, the gripping unit 3 moves parallel to any direction perpendicular to the first reference axis X and becomes eccentric with respect to the first reference axis X.

[0045] Furthermore, when the gripping portion 3 is fixed and the hand main body 2 moves relative to the gripping portion 3, the hand main body 2 moves relative to the gripping portion 3 in a direction perpendicular to the first reference axis X so that the second reference axis Y is eccentric with respect to the first reference axis X.

[0046] Furthermore, when the rotating shaft 71 rotates around the first reference axis X while the second reference axis Y, i.e., the axis C, is constrained to a position eccentric to the first reference axis X, the insert 45a moves relative to the second disk 71d and the eccentric body 42 moves relative to the insert 45a, causing the eccentric body 42 to rotate around the axis C while maintaining the eccentric state between the axis C and the first reference axis X. In this way, the eccentric mechanism 41 not only causes the gripping unit 3 to be eccentric with respect to the first reference axis X, but also transmits the rotation of the rotating shaft 71 around the first reference axis X to the eccentric body 42 as rotation around the axis C eccentric from the first reference axis X. Because the gripping unit 3 is connected to the eccentric body 42, the gripping unit 3 also rotates around the second reference axis Y eccentric from the first reference axis X.

[0047] In this way, the first disk 71c, the rolling element 43, and the second joint 45 each connect the eccentric body 42, i.e., the gripper 3, to the rotating shaft 71 so that the eccentric body 42 is movable in parallel in a direction perpendicular to the first reference axis X. Here, the first disk 71c and the rolling element 43 also function to transmit a load acting in the direction of the first reference axis X of the gripper 3, workpiece, etc. to the rotating shaft 71 so that the load does not act only on the second joint 45. As described above, the second joint 45 also functions to transmit rotation between the first reference axis X and axis C, which are eccentric from each other.

[0048] Next, the operation of the tilting mechanism 47 will be described. When a force that tilts the hand body 2 and the gripper 3 relative to each other acts on at least one of the hand body 2 and the gripper 3, the base 31 rotates freely around the first rotation axis D1 and the second rotation axis D2 with respect to the eccentric body 42. As a result, the second reference axis Y of the base 31 tilts freely with respect to the axis C of the eccentric body 42. The axis C of the eccentric body 42 is parallel to the first reference axis X. Therefore, the second reference axis Y of the base 31 tilts with respect to the first reference axis X.

[0049] 9 is a cross-sectional view of the hand 100 showing a state in which the gripper 3 has rotated around the first rotation axis D1 relative to the hand main body 2. The base 31 and the connecting element 48a are rotating around the first rotation axis D1 relative to the eccentric body 42. As a result, the second reference axis Y of the gripper 3 is inclined with respect to the first reference axis X of the hand main body 2.

[0050] Similarly, the base 31 can rotate about the second rotation axis D2 relative to the connecting element 48a. As a result, the second reference axis Y of the gripper 3 tilts in a direction different from that shown in Figure 9 relative to the first reference axis X of the hand main body 2. Due to the combined occurrence of such rotation of the gripper 3 about the first rotation axis D1 and rotation about the second rotation axis D2, the gripper 3 tilts in any direction relative to the first reference axis X.

[0051] When the gripping portion 3 is fixed and the hand main body 2 moves relative to the gripping portion 3, the hand main body 2 moves relative to the gripping portion 3 so that the second reference axis Y is inclined relative to the first reference axis X.

[0052] Here, when the eccentric body 42 rotates around the axis C while the second reference axis Y is constrained in a tilted state relative to the first reference axis X, the connecting element 48a rotates relative to the eccentric body 42 around the first rotation axis D1 and the base 31 rotates relative to the connecting element 48a around the second rotation axis D2, causing the base 31 to rotate around the second reference axis Y without changing its position.

[0053] In this way, the connecting mechanism 4 supports the gripping unit 3 so that it is eccentric with respect to the first reference axis X, and also supports the gripping unit 3 so that it is tiltable with respect to the first reference axis X. In addition, the connecting mechanism 4 transmits the rotation of the rotating shaft 71 around the first reference axis X to the gripping unit 3 as rotation around the second reference axis Y, with the second reference axis Y of the gripping unit 3 being eccentric or tilted with respect to the first reference axis X.

[0054] -Straight-line mechanism and rotation mechanism- The linear movement mechanism 6 moves the rotating shaft 71 in the direction of the first reference axis X, thereby moving the gripper 3 linearly in the direction of the first reference axis X. The rotation mechanism 7 rotates the rotating shaft 71 around the first reference axis X, thereby rotating the gripper 3 around the first reference axis X. In this example, some of the elements are common between the linear movement mechanism 6 and the rotation mechanism 7. Furthermore, some of the elements of the linear movement mechanism 6 are common to the opening / closing drive mechanism 8. Some of the elements of the rotation mechanism 7 are common to the opening / closing drive mechanism 8. FIG. 10 is an end view of the hand 100 taken along line XX in FIG. 4.

[0055] The linear movement mechanism 6 has a second motor 61, a first gear train 62 that transmits the driving force (i.e., rotational torque) of the second motor 61, a feed screw mechanism 63, a rotating shaft 71, and a gear box 72. Most of the linear movement mechanism 6 is disposed inside the hand main body 2, as shown in FIG.

[0056] As shown in FIG. 4, the rotating shaft 71 is a substantially cylindrical member extending about the first reference axis X. The rotating shaft 71 is supported by a bearing 12 attached to the hand body 2 so as to be movable in the direction of the first reference axis X and rotatable around the first reference axis X. One end of the rotating shaft 71 in the direction of the first reference axis X is referred to as the first end 71a, and the other end in the direction of the first reference axis X is referred to as the second end 71b. The first end 71a is the end on the advancing side in the direction of the first reference axis X. The second end 71b is the end on the retreating side in the direction of the first reference axis X. The rotating shaft 71 penetrates the bottom 21 of the hand body 2. The first end 71a is located outside the hand body 2.

[0057] A first end 71a of the rotary shaft 71 is provided with a flange-shaped first disk 71c and a second disk 71d that extend in a plane perpendicular to the first reference axis X. The first disk 71c is disposed closer to the tip of the first end 71a than the second disk 71d.

[0058] As shown in Fig. 10, the second motor 61 is disposed inside the hand body 2. The second motor 61 is, for example, a servo motor, and is provided with an encoder. In addition, a current sensor is provided in the driver of the second motor 61. The second motor 61 is supported by the hand body 2.

[0059] As shown in FIG. 10 , the first gear train 62 is disposed inside the hand main body 2. The first gear train 62 has a plurality of gears rotatably supported by the hand main body 2. The first gear train 62 includes a first gear 62a, a second gear 62b, a third gear 62c, a fourth gear 62d, a fifth gear 62e, and a sixth gear 62f. The first gear 62a, the second gear 62b, the third gear 62c, the fourth gear 62d, the fifth gear 62e, and the sixth gear 62f are arranged in this order and mesh with each other. The first gear 62a is attached to the output shaft of the second motor 61. The first gear 62a is a drive gear. The second gear 62b, the third gear 62c, the fourth gear 62d, the fifth gear 62e, and the sixth gear 62f are driven gears that transmit the driving force of the second motor 61. The second gear 62b and the sixth gear 62f transmit the driving force of the second motor 61 to the linear movement mechanism 6. The fourth gear 62d transmits the driving force of the second motor 61 to the rotation mechanism 7. The third gear 62c and the fifth gear 62e are so-called intermediate gears (i.e., idle gears).

[0060] 4, the linear movement mechanism 6 has two sets of feed screw mechanisms 63. The feed screw mechanisms 63 have a feed screw 64 and a nut 65 that meshes with the feed screw 64 and serves as a linear movement element.

[0061] The axis F of each lead screw 64 extends parallel to the first reference axis X. One lead screw 64 is non-rotatably connected to the second gear 62b of the first gear train 62. The other lead screw 64 is non-rotatably connected to the sixth gear 62f of the first gear train 62. In other words, the two lead screws 64 rotate around the axis F integrally with the second gear 62b and the sixth gear 62f, respectively.

[0062] The nut 65 meshes with the feed screw 64. The nut 65 is housed in a gear box 72. The gear box 72 prevents the nut 65 from rotating around the axis F. The nut 65 has a cylindrical main body 65a and a flange 65b provided on the main body 65a.

[0063] The nut 65 is elastically pressed against the gear box 72 in the direction of axis F, i.e., the direction of the first reference axis X, by the buffer mechanism 10. More specifically, the buffer mechanism 10 is a spring. Specifically, the buffer mechanism 10 is a coil spring. Note that FIG. 4 shows a simplified illustration of the buffer mechanism 10. The buffer mechanism 10 is disposed on the forward side of the flange 65b in the direction of the first reference axis X. The buffer mechanism 10 is in a compressed state between the flange 65b and the gear box 72. The buffer mechanism 10 presses the gear box 72 against the nut 65 in the forward side in the direction of the first reference axis X by its elastic force. As a result, when the nut 65 moves in the direction of axis F, the gear box 72 also moves integrally with the nut 65 in the direction of axis F, i.e., the direction of the first reference axis X.

[0064] The gear box 72 is supported by linear guides 22 shown in Fig. 10 so as to be movable in the direction of the first reference axis X. Note that the gear box 72 is not shown in Fig. 10. The hand main body 2 has two linear guides 22 extending in the direction of the first reference axis X. Because the gear box 72 is supported by the linear guides 22, it is unable to rotate around the first reference axis X. Furthermore, a rotating shaft 71 is connected to the gear box 72 so as to be rotatable around the first reference axis X but unable to move in the direction of the first reference axis X. When the gear box 72 moves in the direction of the first reference axis X, the rotating shaft 71 also moves in the direction of the first reference axis X together with the gear box 72.

[0065] The rotation mechanism 7 has a second motor 61 that generates a driving force, and a rotating shaft 71 that extends about a first reference axis X and is rotated about the first reference axis X by the driving force of the second motor 61. The rotation mechanism 7 further has a first gear train 62 that transmits the driving force of the second motor 61, a gear box 72, and a second gear train 73 that further transmits the driving force of the second motor 61 from the first gear train 62 to the rotating shaft 71. In other words, the second motor 61, the first gear train 62, the rotating shaft 71, and the gear box 72 of the rotation mechanism 7 are common to the linear movement mechanism 6. The second motor 61 is an example of a rotational driving source.

[0066] 5, the second gear train 73 includes a first gear 73a and a second gear 73b. The first gear 73a and the second gear 73b mesh with each other.

[0067] The first gear 73a is connected to the fourth gear 62d of the first gear train 62 via a ball spline 73c. ​​The axis G of the ball spline 73c extends parallel to the first reference axis X. The ball spline 73c is connected to the fourth gear 62d so as not to rotate. In other words, the ball spline 73c rotates around the axis G integrally with the fourth gear 62d.

[0068] The first gear 73a is coupled to the ball spline 73c so as to be immovable around the axis G but movable in the direction of the axis G. Furthermore, the first gear 73a is supported by the gear box 72 so as to be immovable in the direction of the axis G but rotatable around the axis G. In other words, when the ball spline 73c rotates around the axis G, the first gear 73a rotates around the axis G relative to the gear box 72 and integrally with the ball spline 73c. ​​Furthermore, when the gear box 72 moves in the direction of the first reference axis X, i.e., in the direction of the axis G, the first gear 73a also moves in the direction of the axis G integrally with the gear box 72. The first gear 73a rotates around the axis G integrally with the ball spline 73c even if its position in the direction of the axis G changes.

[0069] The second gear 73b is connected to the rotating shaft 71 so as to be unrotatable around the first reference axis X and unmovable in the direction of the first reference axis X. The second gear 73b rotates around the first reference axis X integrally with the rotating shaft 71 and moves in the direction of the first reference axis X integrally with the rotating shaft 71. The second gear 73b is connected to a portion of the rotating shaft 71 that is located inside the gear box 72. When the gear box 72 moves in the direction of the first reference axis X, the rotating shaft 71 and the second gear 73b also move in the direction of the first reference axis X together with the gear box 72. At this time, the meshing between the first gear 73a and the second gear 73b is maintained.

[0070] The following describes the operations of the linear movement mechanism 6 and the rotation mechanism 7 configured as above. Figure 11 is a cross-sectional view of the hand 100 showing a state in which the linear movement mechanism 6 has advanced the gripper 3 in the direction of the first reference axis X.

[0071] When the second motor 61 is driven, the rotational driving force of the second motor 61 is transmitted to the two feed screws 64 of the linear movement mechanism 6 and the ball spline 73c of the rotation mechanism 7 via the first gear train 62. In other words, when the feed screws 64 rotate, the ball spline 73c also rotates.

[0072] When the lead screw 64 rotates around the axis F, the nut 65 that threads onto the lead screw 64 moves in the direction of the axis F, as shown in Figure 11. When the nut 65 moves in the direction of the axis F, the gear box 72 also moves in the direction of the axis F, i.e., in the direction of the first reference axis X. When the gear box 72 moves in the direction of the first reference axis X, the rotating shaft 71 also moves in the direction of the first reference axis X together with the gear box 72. At this time, the first gear 73a and the second gear 73b move in the direction of the first reference axis X together with the rotating shaft 71 and the gear box 72 while remaining meshed with each other.

[0073] When the ball spline 73c rotates around the axis G, the first gear 73a rotates integrally with the ball spline 73c around the axis G. The rotation of the first gear 73a causes the second gear 73b to rotate around the first reference axis X, and the rotating shaft 71 rotates integrally with the second gear 73b.

[0074] In this way, the rotating shaft 71 moves in the direction of the first reference axis X while rotating around the first reference axis X. The gripping unit 3 is connected to the rotating shaft 71 via the connecting mechanism 4. Therefore, the gripping unit 3 moves in the direction of the first reference axis X together with the rotating shaft 71. Furthermore, the gripping unit 3 moves while rotating around the second reference axis Y.

[0075] -Opening and closing drive mechanism- The opening / closing drive mechanism 8 includes a first motor 81 that generates a driving force, and an opening / closing shaft 84 that extends about a first reference axis X and is rotated about the first reference axis X by the driving force of the first motor 81. The opening / closing drive mechanism 8 opens and closes the finger 32 by operating the operating mechanism 33. The opening / closing drive mechanism 8 has a first belt transmission mechanism 85, a second belt transmission mechanism 86, and a gear box 72. In other words, the gear box 72 of the opening / closing drive mechanism 8 is common to the linear movement mechanism 6 and the rotation mechanism 7. The first motor 81 is an example of an opening / closing drive source.

[0076] As shown in FIG. 5 , the opening / closing shaft 84 is a substantially cylindrical shaft extending about the first reference axis X. One end of the opening / closing shaft 84 in the direction of the first reference axis X is referred to as the first end 84a, and the other end in the direction of the first reference axis X is referred to as the second end 84b. The first end 84a is the end on the advancing side in the direction of the first reference axis X. The second end 84b is the end on the retreating side in the direction of the first reference axis X. The opening / closing shaft 84 is inserted into the rotating shaft 71 so as to be rotatable around the first reference axis X. The second end 84b protrudes outward from the second end 71b of the rotating shaft 71.

[0077] Furthermore, the opening / closing shaft 84 is supported by the gear box 72 so as to be rotatable around the first reference axis X but so as to be immovable in the direction of the first reference axis X. Therefore, when the gear box 72 moves in the direction of the first reference axis X, the opening / closing shaft 84 also moves in the direction of the first reference axis X integrally with the gear box 72. At this time, the rotating shaft 71 also moves in the direction of the first reference axis X integrally with the gear box 72, so the relative positions of the rotating shaft 71 and the opening / closing shaft 84 in the direction of the first reference axis X do not change.

[0078] The opening / closing shaft 84 is inserted into the rotating shaft 71. The rotating shaft 71 is supported by the hand body 2 via the bearing 12, so the opening / closing shaft 84 is essentially supported by the hand body 2.

[0079] As shown in Fig. 10, the first motor 81 is disposed inside the hand body 2. Since the first motor 81 is disposed at a different position from the first gear train 62 in the direction of the first reference axis X, it is shown by a two-dot chain line in Fig. 10. The first motor 81 is, for example, a servo motor, and is provided with an encoder. Furthermore, a current sensor is provided in the driver of the first motor 81. The first motor 81 is supported by the hand body 2.

[0080] As shown in FIG. 10, the first belt transmission mechanism 85 includes a first pulley 85a, a second pulley 85b, and a timing belt 85c. The first pulley 85a is attached to the output shaft of the first motor 81. The second pulley 85b is connected to a ball spline 87 as shown in FIG. 5. The ball spline 87 has an axis E parallel to the first reference axis X. The ball spline 87 is supported by the hand body 2 so as to be rotatable about the axis E. The second pulley 85b is connected to the ball spline 87 so as not to rotate about the axis E or move in the direction of the axis E. The timing belt 85c is wound around the first pulley 85a and the second pulley 85b. The driving force of the first motor 81 is transmitted to the second pulley 85b via the first pulley 85a and the timing belt 85c. The ball spline 87 rotates integrally with the second pulley 85b about the axis E.

[0081] As shown in FIG. 5 , the second belt transmission mechanism 86 includes a third pulley 86a, a fourth pulley 86b, and a timing belt 86c. The third pulley 86a is coupled to the ball spline 87 so as to be unrotatable around axis E but movable in the direction of axis E. The third pulley 86a is supported by the gear box 72 so as to be rotatable around axis E but movable in the direction of axis E. The fourth pulley 86b is coupled to the opening-closing shaft 84 so as to be unrotatable around the first reference axis X but movable in the direction of axis E. More specifically, the fourth pulley 86b is coupled to a second end 84b of the opening-closing shaft 84 that protrudes from the rotating shaft 71. The fourth pulley 86b is supported by the gear box 72 so as to be rotatable around the first reference axis X but movable in the direction of axis X. The timing belt 86c is wound around the third pulley 86a and the fourth pulley 86b. The rotation of the ball spline 87 around the axis E is transmitted to the fourth pulley 86b via the third pulley 86a and the timing belt 86c.

[0082] In this way, the driving force of the first motor 81 is transmitted to the opening-closing shaft 84 via the first belt transmission mechanism 85 and the second belt transmission mechanism 86. As a result, the opening-closing shaft 84 rotates around the first reference axis X. Since the opening-closing shaft 84 is inserted into the rotating shaft 71 so as to be rotatable around the first reference axis X, the opening-closing shaft 84 rotates around the first reference axis X independently from the rotating shaft 71. Furthermore, the opening-closing shaft 84 and the second belt transmission mechanism 86 are supported by the gear box 72 so as to be immovable in the direction of the first reference axis X. Therefore, when the gear box 72 moves in the direction of the first reference axis X, the opening-closing shaft 84 and the second belt transmission mechanism 86 move in the direction of the first reference axis X together with the gear box 72. At this time, the third pulley 86a moves in the direction of the axis E along the ball spline 87. Even if the opening / closing shaft 84 and the second belt transmission mechanism 86 move in the direction of the first reference axis X together with the gearbox 72, the driving force of the first motor 81 is transmitted to the opening / closing shaft 84 via the first belt transmission mechanism 85 and the second belt transmission mechanism 86.

[0083] 5, the connecting mechanism 4 has a transmission mechanism 5 that transmits the driving force of the opening / closing drive mechanism 8 to the gripping portion 3. The transmission mechanism 5 transmits the driving force of the opening / closing drive mechanism 8 to the gripping portion 3 in a state in which the second reference axis Y is eccentric or inclined with respect to the first reference axis X. The transmission mechanism 5 includes a first joint 51 that connects the opening / closing shaft 84 and the operating mechanism 33.

[0084] The first joint 51 transmits the rotation of the opening / closing shaft 84 to the operating mechanism 33 in a state in which the second reference axis Y is eccentric or inclined relative to the first reference axis X. The first joint 51 is a joint that transmits rotation even if there is a misalignment, such as an angular misalignment, or eccentricity, between the two shafts. Specifically, the first joint 51 includes a first ball coupling 52 and a second ball coupling 53. Note that the first ball coupling 52 and the second ball coupling 53 are illustrated in a simplified form. The first ball coupling 52 and the second ball coupling 53 are joints that combine the functions of a universal joint (i.e., a universal joint) and a spline, respectively, and are joints that transmit rotation even if there is a misalignment, such as an angular misalignment, or eccentricity, between the two shafts.

[0085] The first ball coupling 52 connects the first end 84a of the opening / closing shaft 84 to the second ball coupling 53. The first ball coupling 52 transmits the rotation of the opening / closing shaft 84 about the first reference axis X to the second ball coupling 53. The second ball coupling 53 connects the first ball coupling 52 to the lead screw 37 of the operating mechanism 33. The second ball coupling 53 transmits the rotation of the first ball coupling 52 to the lead screw 37 as rotation about the second reference axis Y.

[0086] Even if the second reference axis Y is eccentric or inclined with respect to the first reference axis X, the first ball coupling 52 and the second ball coupling 53 can absorb the eccentricity and angular deviation between the first reference axis X and the second reference axis Y and transmit the rotation around the first reference axis X as a rotation around the second reference axis Y.

[0087] A description will be given of the operation of the opening / closing drive mechanism 8 and the transmission mechanism 5 configured as above. Fig. 12 is a cross-sectional view of the hand 100 showing a state in which the opening / closing drive mechanism 8 has caused the fingers 32 to open.

[0088] When the first motor 81 is operated, the rotational driving force of the first motor 81 is transmitted to the ball spline 87 via the first pulley 85a, the timing belt 85c, and the second pulley 85b, as shown in FIG. 5 . When the ball spline 87 rotates around the axis E, the third pulley 86a connected to the ball spline 87 rotates around the axis E. The rotation of the third pulley 86a is transmitted to the opening-closing shaft 84 via the timing belt 86c and the fourth pulley 86b. Thus, the opening-closing shaft 84 rotates around the first reference axis X. The rotation of the opening-closing shaft 84 around the first reference axis X is transmitted to the feed screw 37 of the operating mechanism 33 via the transmission mechanism 5 as rotation around the second reference axis Y. When the feed screw 37 rotates around the second reference axis Y, the block 38 moves in the direction of the second reference axis Y. At this time, as shown in FIG. 12, when the block 38 approaches the bottom 34c, the fingers 32 move radially outward around the second reference axis Y. On the other hand, as shown in FIG. 4, when the block 38 moves away from the bottom 34c, the fingers 32 move radially inward. In this way, the opening and closing drive mechanism 8 opens and closes the fingers 32. This causes the multiple fingers 32 to grip and release the grip of the workpiece. At this time, the multiple fingers 32 open and close so that their distances from the second reference axis Y are the same. In other words, the multiple fingers 32 open and close around the second reference axis Y.

[0089] The direction of movement of the block 38 in the direction of the second reference axis Y, i.e., whether the fingers 32 are open or closed, is switched by the rotation direction of the first motor 81. Furthermore, the radial position of the fingers 32 about the second reference axis Y, i.e., the degree of opening or closing of the fingers 32, is detected based on the encoder output of the first motor 81. Furthermore, the rotational torque of the first motor 81 when the three fingers 32 are opening or closing is detected based on the detection result of the current sensor.

[0090] Here, when the linear movement mechanism 6 moves the rotating shaft 71 and the gripping unit 3 in the direction of the first reference axis X, the opening / closing shaft 84 and the second belt transmission mechanism 86 supported by the gear box 72 also move in the direction of the first reference axis X together with the rotating shaft 71, etc. The driving force of the first motor 81 remains in a state in which it can be transmitted to the opening / closing shaft 84 via the first belt transmission mechanism 85 and the second belt transmission mechanism 86. In other words, even if the rotating shaft 71 and the gripping unit 3 move in the direction of the first reference axis X, the fingers 32 of the gripping unit 3 can be opened and closed by the driving force of the first motor 81.

[0091] However, when the rotation shaft 71 and the gripping portion 3 are moved in the direction of the first reference axis X by the linear movement mechanism 6, the gripping portion 3 is rotated around the first reference axis X by the rotation mechanism 7. That is, the base 31 and the fingers 32 rotate around the first reference axis X. At this time, if the opening / closing shaft 84 does not rotate around the first reference axis X, the feed screw 37 also does not rotate around the first reference axis X, and therefore the base 31 rotates around the first reference axis X relative to the feed screw 37. As a result, the block 38 moves in the direction of the second reference axis Y, and the open / closed state of the fingers 32 changes.

[0092] Therefore, when the rotating shaft 71 moves in the direction of the first reference axis X and the open / closed state of the fingers 32 is maintained, the first motor 81 rotates the opening / closing shaft 84 around the first reference axis X in accordance with the rotation of the gripping unit 3 around the first reference axis X. Specifically, the torque of the first motor 81 is controlled so that the torque of the first motor 81 is maintained constant. As a result, the fingers 32 move in the direction of the first reference axis X while rotating around the first reference axis X while maintaining the open / closed state (for example, while the fingers 32 maintain a state in which they grip a workpiece).

[0093] Furthermore, because the gripper 3 is supported by the coupling mechanism 4, the second reference axis Y of the gripper 3 may be eccentric with respect to the first reference axis X, as shown in FIG. 8 . Alternatively, the second reference axis Y of the gripper 3 may be inclined with respect to the first reference axis X, as shown in FIG. 9 . Even in such a case, the first ball coupling 52 and the second ball coupling 53 are deformed, thereby maintaining the coupling state between the opening / closing shaft 84 and the operating mechanism 33. Furthermore, rotation of the opening / closing shaft 84 about the first reference axis X is transmitted to the operating mechanism 33 as rotation about the second reference axis Y via the first ball coupling 52 and the second ball coupling 53. Here, because the first joint 51 includes two joints, i.e., the first ball coupling 52 and the second ball coupling 53, the first joint 51 can flexibly accommodate eccentricity and inclination between the first reference axis X and the second reference axis Y.

[0094] -Buffer mechanism- The buffer mechanism 10 elastically supports the grip portion 3 in the direction of the first reference axis X. The buffer mechanism 10 absorbs the force acting on the grip portion 3 in the direction of the first reference axis X by the elastic support of the grip portion 3.

[0095] As described above, the buffer mechanism 10 is a spring. As shown in FIG. 4 , the buffer mechanism 10 elastically connects the nut 65 of the feed screw mechanism 63 to the gear box 72. The hand 100 has two feed screw mechanisms 63 and therefore two buffer mechanisms 10. Specifically, the buffer mechanism 10 is housed in the gear box 72. The nut 65 and the gear box 72 are elastically connected so that the gear box 72 can be displaced backward in the direction of the first reference axis X relative to the nut 65. The gear box 72 is connected to the opening / closing shaft 84 and the rotating shaft 71. The gripper 3 is connected to the opening / closing shaft 84 and the rotating shaft 71 via the connecting mechanism 4. In other words, the buffer mechanism 10 essentially supports the gripper 3 so that the gripper 3 can be displaced backward in the direction of the first reference axis X.

[0096] In this buffer mechanism 10, when a force acts on the grip portion 3 (for example, the finger 32) toward the retreating side in the direction of the first reference axis X, the force is transmitted from the grip portion 3 to the nut 65 via the connecting mechanism 4, the rotating shaft 71, the gear box 72, and the buffer mechanism 10. At this time, the buffer mechanism 10 undergoes elastic deformation, i.e., compressive deformation, and the gear box 72 moves toward the retreating side in the direction of the first reference axis X. The open-close shaft 84, the rotating shaft 71, and the grip portion 3 also move toward the retreating side in the direction of the first reference axis X integrally with the gear box 72. In this way, the force acting on the grip portion 3 is absorbed by the buffer mechanism 10.

[0097] - Locking mechanism - 4, the locking mechanism 9 has a first engaging portion 91 provided on the hand body 2 and a second engaging portion 92 provided on the gripping portion 3. The locking mechanism 9 restricts the operation of the connecting mechanism 4, i.e., the operation of the eccentric mechanism 41 and the tilting mechanism 47, by engaging the first engaging portion 91 with the second engaging portion 92, and releases the restriction on the operation of the connecting mechanism 4 by disengaging the first engaging portion 91 from the second engaging portion 92.

[0098] More specifically, the first engagement portion 91 is provided on the bottom 21 outside the hand body 2. The first engagement portion 91 is a substantially cylindrical shape extending with the first reference axis X as its axis.

[0099] The second engagement portion 92 is provided on the ceiling 34b outside the base 31. The second engagement portion 92 faces the first engagement portion 91. The second engagement portion 92 is a substantially cylindrical member extending about the second reference axis Y. The second engagement portion 92 is disposed on the ceiling 34b so as to surround the connecting mechanism 4. In other words, the connecting mechanism 4 is disposed inside the second engagement portion 92.

[0100] The second engagement portion 92 engages with the first engagement portion 91 by fitting inside the first engagement portion 91. That is, the outer diameter of the second engagement portion 92 is slightly smaller than the inner diameter of the first engagement portion 91. Because the second engagement portion 92 is provided on the base 31, when the connecting mechanism 4 is moved in the first reference axis X direction by the linear movement mechanism 6, the relative position of the first engagement portion 91 and the second engagement portion 92 in the first reference axis X direction changes. The second engagement portion 92 switches between engagement and disengagement with the first engagement portion 91 due to the linear movement of the connecting mechanism 4 by the linear movement mechanism 6. Specifically, when the gripper 3 approaches the hand main body 2 in the first reference axis X direction, the second engagement portion 92 fits into and engages with the first engagement portion 91. On the other hand, when the gripper 3 moves away from the hand main body 2 in the first reference axis X direction, the engagement between the second engagement portion 92 and the first engagement portion 91 is released.

[0101] The locking mechanism 9 restricts the operation of the eccentric mechanism 41 and the tilting mechanism 47 by engaging the second engaging portion 92 with the first engaging portion 91. Specifically, as shown in FIG. 4 , the engagement between the first engaging portion 91 and the second engaging portion 92 prevents the gripping portion 3 from moving in a direction perpendicular to the first reference axis X and from moving in a direction inclined about the second reference axis Y relative to the first reference axis X. At this time, the first reference axis X and the second reference axis Y are aligned on a straight line. In this way, the locking mechanism 9 restricts the operation of the eccentric mechanism 41 and the tilting mechanism 47 by engaging the first engaging portion 91 with the second engaging portion 92 while the first reference axis X and the second reference axis Y are aligned on a straight line.

[0102] Even when the first engaging portion 91 and the second engaging portion 92 are engaged with each other, the first engaging portion 91 and the second engaging portion 92 do not restrict the relative movement of the hand body 2 and the gripping portion 3 in the direction of the first reference axis X. Therefore, even when the hand body 2 and the gripping portion 3 are in the restricted state by the locking mechanism 9, the buffer mechanism 10 functions effectively.

[0103] When the connecting mechanism 4 is moved by the rectilinear mechanism 6 in a direction in which the gripper 3 moves away from the hand body 2 in the direction of the first reference axis X, the second engaging portion 92 eventually comes out of the first engaging portion 91, and the engagement between the first engaging portion 91 and the second engaging portion 92 is released, as shown in Fig. 11. In this state, the connecting mechanism 4 can freely decenter and tilt the gripper 3 with respect to the first reference axis X.

[0104] Next, a description will be given of the control of the robot arm 120 and the hand 100 by the control device 130. Fig. 13 shows a schematic hardware configuration of the control device 130. The control device 130 has a control unit 131, a storage unit 132, and a memory 133.

[0105] The control unit 131 reads out a program from the storage unit 132 into the memory 133 and loads it to implement various functions of the control device 130. The control unit 131 is formed of a processor such as a CPU (Central Processing Unit). The control unit 131 may also be formed of an MCU (Micro Controller Unit), an MPU (Micro Processor Unit), an FPGA (Field Programmable Gate Array), a PLC (Programmable Logic Controller), a system LSI (Large Scale Integrated Circuit), or the like.

[0106] The control unit 131 controls the motors of the robot arm 120, thereby controlling the operation of the robot arm 120. The control unit 131 also controls the first motor 81 and the second motor 61, thereby controlling the operation of the hand 100.

[0107] The storage unit 132 stores programs executed by the control unit 131 and various data. The storage unit 132 is formed of a non-volatile memory, a hard disk drive (HDD), a solid state drive (SSD), etc. The memory 133 temporarily stores data, etc. The memory 133 is formed of, for example, a volatile memory.

[0108] Next, specific control by the control device 130 will be described. An insertion operation will be described in which a workpiece W1 held by the hand 100 is inserted into a hole H formed in another workpiece W2. The workpiece W1 is cylindrical and extends about an axis M. The hole H is a circular hole into which the workpiece W1 fits. The hole H extends about an axis N. FIG. 14 is a flowchart of the insertion operation.

[0109] First, in step S1, the control device 130 causes the robot arm 120 and the hand 100 to perform a gripping operation to grip the workpiece W1 with the gripper 3. Specifically, the control device 130 causes the three fingers 32 to open wider than the outer diameter of the workpiece W1. The control device 130 moves the robot arm 120 so that one end of the workpiece W1 is positioned inside the three fingers 32. Next, the control device 130 closes the three fingers 32. As a result, the three fingers 32 grip the workpiece W1. At this time, the axis M of the workpiece W1 is aligned in a straight line with the second reference axis Y. Note that the first reference axis X and the second reference axis Y are aligned in a straight line, so the axis M of the workpiece W1 is also aligned in a straight line with the first reference axis X.

[0110] At this time, the control device 130 places the locking mechanism 9 in a restrained state. In other words, the first engagement portion 91 and the second engagement portion 92 are engaged, and the gripper 3 is not eccentric or tilted with respect to the first reference axis X of the hand body 2. This allows the control device 130 to accurately align the gripper 3 during the gripping operation or a subsequent operation.

[0111] Alternatively, the control device 130 may execute the gripping operation with the locking mechanism 9 released. Because the gripping unit 3 can be freely decentered and tilted with respect to the first reference axis X, the position of the gripping unit 3 is naturally adjusted so that the gripping unit 3 can properly grip the workpiece W1, even if the gripping unit 3 and the workpiece W1 are not precisely aligned.

[0112] After gripping the workpiece W1 with the gripping unit 3, the control device 130 causes the robot arm 120 and the hand 100 to perform a contact operation to bring the workpiece W1 into contact with the opening edge of the hole H in step S2. Fig. 15 is a schematic front view of the hand 100 upon completion of the contact operation. Fig. 16 is a schematic plan view showing the positional relationship between the workpiece W1 and the hole H upon completion of the contact operation.

[0113] 15 , the control device 130 moves the robot arm 120 so that the workpiece W1 contacts the edge of the opening of the hole H with the first reference axis X and the second reference axis Y tilted relative to the axis N of the hole H. The robot arm 120 brings the edge of the end of the workpiece W1 opposite the end held by the fingers 32 into contact with the edge of the opening of the hole H. The axis M of the workpiece W1 is aligned in a straight line with the second reference axis Y, and therefore the axis M of the workpiece W1 is also tilted relative to the axis N of the hole H.

[0114] Since the workpiece W1 is cylindrical, the edge of the workpiece W1 is circular. Since the hole H is a round hole, the opening edge of the hole H is also circular. When the circular edge of the workpiece W1 comes into contact with the circular opening edge of the hole H with the axis M of the workpiece W1 tilted relative to the axis N of the hole H, the workpiece W1 comes into point contact or line contact with the opening edge of the hole H. In this example, the robot arm 120 positions the axis M and the axis N in a twisted position, thereby bringing the workpiece W1 into point contact with the opening edge of the hole H at point P, as shown in FIG. 16 .

[0115] During the contact operation, the locking mechanism 9 is in a restrained state, restraining the eccentric mechanism 41 and the tilting mechanism 47. This allows the control device 130 to accurately align the gripping unit 3, i.e., the positioning of the workpiece W1. Note that the buffer mechanism 10 functions effectively even when the locking device 9 is in a restrained state, so that the buffer mechanism 10 can absorb the impact that the workpiece W1 receives when it is brought into contact with the opening edge of the hole H. This allows the robot arm 120 and hand 100 to perform work quickly.

[0116] Next, in step S3, the control device 130 causes the robot arm 120 and the hand 100 to perform a release operation to release the constraint of the connecting mechanism 4 by the locking mechanism 9. Fig. 17 is a schematic diagram of the hand 100 as seen from the front during the release operation.

[0117] Specifically, the linear movement mechanism 6 advances the connecting mechanism 4 from the hand main body 2 in the direction of the first reference axis X, thereby disengaging the first engaging portion 91 from the second engaging portion 92. At the same time, the robot arm 120 retreats the hand main body 2 in the direction of the first reference axis X by the same amount as the advancement of the connecting mechanism 4 (see the thick arrow). In other words, as shown in FIG. 17 , the absolute positions of the gripper 3 and the connecting mechanism 4 remain unchanged, and the hand main body 2 is displaced in the direction of the first reference axis X relative to the gripper 3 and the connecting mechanism 4. As a result, the position and posture of the workpiece W1 with respect to the hole H do not change, that is, the axis M of the workpiece W1 is tilted with respect to the axis N of the hole H, and the workpiece W1 remains in point contact with the edge of the opening of the hole H, and the restraint by the locking mechanism 9 is released.

[0118] The amount of advancement of the connecting mechanism 4 in the direction of the first reference axis X to release the engagement between the first engaging portion 91 and the second engaging portion 92 is determined by the dimensions of the first engaging portion 91 and the second engaging portion 92, etc. The control device 130 completes the release operation when it has advanced the connecting mechanism 4 in the direction of the first reference axis X by the amount required for disengagement.

[0119] When the restraint by the locking mechanism 9 is released, in step S4, the control device 130 causes the hand 100 to perform an introduction operation to partially insert the workpiece W1 into the hole H by operating the rotation mechanism 7 in a state where the first reference axis X is inclined with respect to the axis N of the hole H. FIG. 18 is a schematic plan view showing the positional relationship between the workpiece W1 and the hole H at the start of the introduction operation. FIG. 19 is a schematic front view of the hand 100 at the completion of the introduction operation.

[0120] Specifically, the control device 130 stops the movement of the robot arm 120 upon completion of the release operation, while continuing to advance the connecting mechanism 4 in the direction of the first reference axis X by the linear movement mechanism 6. At this time, the rotation mechanism 7 also operates simultaneously with the linear movement mechanism 6. Therefore, while the gripper 3 is in a state in which it can freely move eccentrically and tilt with respect to the first reference axis X, the connecting mechanism 4 advances in the direction of the first reference axis X while rotating around the first reference axis X.

[0121] 18, the workpiece W1 rotates from point contact with the edge of the hole H about the second reference axis Y, i.e., about axis M (see the dashed arrow). As a result, the workpiece W1 rotates about point P as a pivot, and is guided along the edge of the hole H until the end of the workpiece W1 fits into the hole H (see the bold arrow). At this time, the workpiece W1 changes its position so that axis M coincides with axis N of the hole H. Because the locking mechanism 9 no longer restricts the connecting mechanism 4, the gripping unit 3 can freely deviate and tilt with respect to the first reference axis X. In other words, the workpiece W1 can change its position while being held by the gripping unit 3 so that axis M coincides with axis N. Furthermore, the tilting mechanism 47 transmits the rotation of the rotating shaft 71 about the first reference axis X to the gripping unit 3 as rotation about the second reference axis Y while tilting the second reference axis Y of the gripping unit 3 with respect to the first reference axis X. Therefore, the workpiece W1 rotates around the second reference axis Y, i.e., around the axis M, and changes its posture so that the axis M coincides with the axis N. In this way, the end of the workpiece W1 is smoothly inserted into the hole H. When the amount of advancement of the connecting mechanism 4 in the direction of the first reference axis X after the start of the introduction operation reaches a predetermined amount, the control device 130 completes the introduction operation.

[0122] 19, at the completion of the introduction operation, the second reference axis Y of the gripper 3 is inclined with respect to the first reference axis X. The second reference axis Y and the axis M of the workpiece W1 are aligned on a straight line with the axis N of the hole H. The position and posture of the hand main body 2 have not changed since the start of the introduction operation.

[0123] Next, in step S5, the control device 130 causes the robot arm 120 and the hand 100 to perform an insertion operation to insert the workpiece W1 into the hole H by operating the rotation mechanism 7 in a state in which the first reference axis X is parallel to the axis N of the hole H. FIG. 20 is a schematic front view of the hand 100 during the insertion operation. FIG. 21 is a schematic plan view showing the positional relationship between the workpiece W1 and the hole H during the insertion operation. FIG. 22 is a schematic front view of the hand 100 upon completion of the insertion operation.

[0124] Specifically, as shown in FIG. 20 , the control device 130 changes the inclination of the hand main body 2 using the robot arm 120 to make the first reference axis X parallel to the axis N of the hole H. Because the end of the workpiece W1 is inserted into the hole H, the gripper 3 is constrained in a state in which the second reference axis Y is aligned on a straight line with the axis N of the hole H. The presence of the connecting mechanism 4 allows the gripper 3 to be freely eccentric and inclined with respect to the first reference axis X. As a result, the hand main body 2 can be in a state in which the first reference axis X is parallel to and eccentric with respect to the second reference axis Y and the axis N. Note that, in some cases, the first reference axis X may be aligned on a straight line with the second reference axis Y and the axis N.

[0125] In this state, the control device 130 operates the linear movement mechanism 6 and the rotation mechanism 7. With the second reference axis Y of the gripping unit 3 eccentric with respect to the first reference axis X, the tilting mechanism 47 can transmit the rotation of the rotating shaft 71 about the first reference axis X to the gripping unit 3 as rotation about the second reference axis Y. As a result, the workpiece W1 advances in the direction of the second reference axis Y while rotating about the second reference axis Y. Because the second reference axis Y, the axis M, and the axis N are aligned on a straight line, the workpiece W1 is inserted into the hole H while rotating about the axis N with the axis M coinciding with the axis N, as shown in FIG. 21 . As a result, the workpiece W1 is smoothly inserted into the hole H.

[0126] When the amount of advancement of the connecting mechanism 4 in the direction of the first reference axis X after the start of the insertion operation reaches a predetermined amount, the control device 130 completes the insertion operation. Note that if the workpiece W1 reaches the bottom of the hole H before the insertion operation is completed, the buffer mechanism 10 deforms to absorb the movement of the gripper 3 and the workpiece W1.

[0127] Thereafter, the control device 130 operates the open / close drive mechanism 8 to release the grip of the workpiece W1 by the fingers 32. In this way, the control device 130 completes the insertion operation of the workpiece W1.

[0128] In this manner, in the insertion operation, the second reference axis Y is tilted relative to the axis N of the hole H, and the workpiece W1 is rotated about the second reference axis Y from a state in which the workpiece W1 is in point contact with the edge of the hole H, thereby inserting the workpiece W1 into the hole H (hereinafter, this type of insertion is referred to as "rotational tilt insertion"). By using the hand 100 for the insertion operation, rotational tilt insertion of the workpiece W1 can be easily achieved. That is, by operating the rotation mechanism 7 from a state in which the second reference axis Y is tilted relative to the axis N of the hole H and the workpiece W1 is in point contact with the edge of the hole H, i.e., by rotating the rotating shaft 71 about the first reference axis X, the workpiece W1 is inserted into the hole H so that the axis M coincides with the axis N, and the gripper 3 is tilted relative to the first reference axis X to make this possible. Even when the gripper 3 is tilted relative to the first reference axis X, the connecting mechanism 4 can transmit the rotation of the rotating shaft 71 about the first reference axis X to the gripper 3 as rotation about the second reference axis Y. Since the workpiece W1 is inserted into the hole H while being rotated around the second reference axis Y, the workpiece W1 can be inserted into the hole H more smoothly.

[0129] Furthermore, the connecting mechanism 4 can be moved in the direction of the first reference axis X by the linear movement mechanism 6. Therefore, without moving the hand main body 2, i.e., without moving the robot arm 120, the workpiece W1 can be inserted into the hole H while changing the inclination of the workpiece W1.

[0130] In addition, the driving source of the linear movement mechanism 6 and the rotation mechanism 7 is the common second motor 61, and the linear movement mechanism 6 and the rotation mechanism 7 operate simultaneously, so that it is easy to advance the rotation shaft 71 in the direction of the first reference axis X while rotating it around the first reference axis X.

[0131] Furthermore, the hand 100 is equipped with a locking mechanism 9, which allows the position of the gripping portion 3 to be stabilized as needed. For example, by restraining the connecting mechanism 4 with the locking mechanism 9 when the workpiece W1 is brought into point contact with the opening edge of the hole H, the position of the workpiece W1 can be stabilized and the workpiece W1 can be aligned with high precision.

[0132] According to the hand 100 configured in this manner, the connecting mechanism 4 supports the gripper 3 so that it can be tilted and eccentric with respect to the first reference axis X, i.e., it supports it flexibly, so that even if the position of the workpiece gripped by the gripper 3 is deviated from the desired position, the connecting mechanism 4 can absorb the positional deviation and place the workpiece in the desired position. Therefore, the positioning accuracy required of the hand 100 can be reduced.

[0133] The hand 100 does not achieve this flexible support of the gripper 3 by relying on play between parts or the rigidity of the parts themselves, but by using the eccentric mechanism 41 and tilt mechanism 47. When the gripper 3 is flexibly supported by play between parts, the flexibility of the support is determined by circumstances, making it difficult to design and manage. On the other hand, the eccentric mechanism 41 and tilt mechanism 47 make it possible to appropriately design and manage the flexibility of the support of the gripper 3.

[0134] In addition, the connecting mechanism 4 flexibly supports the gripper 3, rather than flexibly supporting the entire hand 100 including the hand body 2. In other words, the weight of the members supported by the connecting mechanism 4 is reduced compared to when the connecting mechanism 4 also supports the hand body 2. As a result, the inertia (i.e., the moment of inertia) of the members supported by the connecting mechanism 4 is reduced, improving responsiveness when tilting or decentering the gripper 3 with respect to the first reference axis X.

[0135] Furthermore, in order to achieve low inertia for the gripper 3, the opening / closing drive mechanism 8 that opens and closes the gripper 3 is disposed in the hand main body 2. The connecting mechanism 4 has a transmission mechanism 5 that transmits the driving force of the opening / closing drive mechanism 8 to the gripper 3 in a state in which the second reference axis Y is eccentric or tilted with respect to the first reference axis X. Specifically, the transmission mechanism 5 has a first joint 51 that includes a first ball coupling 52 and a second ball coupling 53. Even in a configuration in which the opening / closing drive mechanism 8 is disposed in the hand main body 2 and the gripper 3 is supported by the connecting mechanism 4 so that it can be eccentric or tilted, the provision of such a transmission mechanism 5 makes it possible to open and close the gripper 3 with the driving force of the opening / closing drive mechanism 8.

[0136] The gripping portion 3 is also configured to rotate around the second reference axis Y. This allows the workpiece to be easily inserted into the hole by using the hand 100. In other words, when the workpiece is inserted into the hole while being rotated, the workpiece can be inserted into the hole more smoothly than when the workpiece is simply inserted into the hole without being rotated.

[0137] Furthermore, in order to achieve low inertia for the gripping unit 3, the rotation mechanism 7 that rotates the gripping unit 3 around the second reference axis Y is disposed in the hand main body 2. The connecting mechanism 4 transmits the driving force of the rotation mechanism 7 to the gripping unit 3 in a state in which the second reference axis Y is eccentric or tilted with respect to the first reference axis X. As a result, even in a configuration in which the rotation mechanism 7 is disposed in the hand main body 2 and the gripping unit 3 is supported by the connecting mechanism 4 so that it can be tilted or eccentric, the gripping unit 3 can be rotated by the driving force of the rotation mechanism 7.

[0138] Furthermore, since the hand 100 is equipped with a locking mechanism 9, the gripping unit 3 is not always able to be decentered or tilted with respect to the first reference axis X, and the locking mechanism 9 can prevent the gripping unit 3 from being decentered or tilted. By restricting the connecting mechanism 4 with the locking mechanism 9, the positional accuracy of the gripping unit 3 can be improved.

[0139] Furthermore, when the connecting mechanism 4 is constrained by the locking mechanism 9, the second reference axis Y is aligned with the first reference axis X. Therefore, when rotation about the first reference axis X is generated in the hand main body 2, the gripping portion 3 can be rotated about the second reference axis Y.

[0140] Furthermore, the hand 100 has the rectilinear mechanism 6 that moves the connecting mechanism 4 linearly in the direction of the first reference axis X, and therefore can switch between engagement and disengagement of the first engaging portion 91 and the second engaging portion 92 of the locking mechanism 9 using the rectilinear mechanism 6. In other words, there is no need to provide a separate drive mechanism for switching between engagement and disengagement of the first engaging portion 91 and the second engaging portion 92.

[0141] Furthermore, since the hand 100 is equipped with the buffer mechanism 10, when an excessive force acts on the gripper 3 in the direction of the first reference axis X, such force can be absorbed by the buffer mechanism 10. As a result, the precision of the position control of the gripper 3 in the direction of the first reference axis X can be relaxed.

[0142] As described above, the hand 100 comprises a hand main body 2 having a predetermined first reference axis X defined therein, a gripping portion 3 having a predetermined second reference axis Y defined therein for gripping a workpiece, and a connecting mechanism 4 for connecting the gripping portion 3 to the hand main body 2, and the connecting mechanism 4 includes at least one of an eccentric mechanism 41 for supporting the gripping portion 3 so that the second reference axis Y is eccentric with respect to the first reference axis X, and a tilting mechanism 47 for supporting the gripping portion 3 so that the second reference axis Y is tiltable with respect to the first reference axis X.

[0143] According to this configuration, the hand 100 grips a workpiece using the gripper 3, whose second reference axis Y is eccentric or tiltable relative to the first reference axis X. Positional deviation of the gripper 3 can be absorbed by the eccentric mechanism 41 or tilt mechanism 47. Therefore, even if the positional accuracy of the gripper 3 is not very high, the gripper 3 can perform work appropriately. Furthermore, the connecting mechanism 4 supports the gripper 3 eccentrically or tiltably, rather than supporting the entire hand 100 including the hand body 2. This reduces the moment of inertia of the members supported by the connecting mechanism 4. As a result, responsiveness can be improved when tilting or eccentricating the gripper 3 relative to the first reference axis X.

[0144] The linking mechanism 4 also includes both an eccentric mechanism 41 and a tilt mechanism 47 .

[0145] With this configuration, the connecting mechanism 4 can absorb both the eccentricity and the angular deviation of the second reference axis Y relative to the first reference axis X. In other words, the connecting mechanism 4 can more flexibly absorb the positional deviation of the grip portion 3.

[0146] Furthermore, the hand body 2 has an opening / closing drive mechanism 8 that opens and closes the gripping portion 3, and the connecting mechanism 4 has a transmission mechanism 5 that transmits the driving force of the opening / closing drive mechanism 8 to the gripping portion 3, and the transmission mechanism 5 transmits the driving force of the opening / closing drive mechanism 8 to the gripping portion 3 in a state where the second reference axis Y is eccentric or inclined with respect to the first reference axis X.

[0147] According to this configuration, by providing the opening / closing drive mechanism 8 that opens and closes the gripper 3 in the hand body 2, it is possible to promote weight reduction of the gripper 3. Furthermore, even in a configuration in which the opening / closing drive mechanism 8 is provided in the hand body 2 and the connecting mechanism 4 supports the gripper 3 so that it can be eccentrically or tilted with respect to the first reference axis X, the drive force of the opening / closing drive mechanism 8 can be appropriately transmitted to the gripper 3 via the transmission mechanism 5. In other words, by providing the transmission mechanism 5, it is possible to both drive the gripper 3 by the opening / closing drive mechanism 8 arranged in the hand body 2 and support the gripper 3 so that it can be eccentrically or tilted by the connecting mechanism 4.

[0148] Specifically, the gripping portion 3 has a base 31, a plurality of fingers 32 supported by the base 31, and an operating mechanism 33 that opens and closes the plurality of fingers 32, the opening and closing drive mechanism 8 includes a first motor 81 that generates a driving force, and an opening and closing shaft 84 that extends about a first reference axis X and is rotated around the first reference axis X by the driving force of the first motor 81, the transmission mechanism 5 includes a first joint 51 that connects the opening and closing shaft 84 and the operating mechanism 33, the connecting mechanism 4 includes a tilting mechanism 47, and the first joint 51 transmits the rotation of the opening and closing shaft 84 to the operating mechanism 33 with the second reference axis Y inclined with respect to the first reference axis X.

[0149] According to this configuration, the opening / closing drive mechanism 8 rotates the opening / closing shaft 84 around the first reference axis X. The opening / closing shaft 84 is connected to the operating mechanism 33 of the gripper 3 via the first joint 51 of the transmission mechanism 5. As a result, even if the second reference axis Y is inclined with respect to the first reference axis X, the rotation of the opening / closing shaft 84 around the first reference axis X is transmitted to the operating mechanism 33. As a result, the multiple fingers 32 can be opened and closed appropriately.

[0150] Furthermore, the connecting mechanism 4 further includes an eccentric mechanism 41, and the first joint 51 transmits the rotation of the opening / closing shaft 84 to the operating mechanism 33 in a state in which the second reference axis Y is eccentric with respect to the first reference axis X.

[0151] According to this configuration, the connecting mechanism 4 includes both the eccentric mechanism 41 and the tilt mechanism 47. The first joint 51 can transmit the rotation of the opening / closing shaft 84 to the operating mechanism 33 even when the second reference axis Y is eccentric or tilted with respect to the first reference axis X. As a result, even when the gripping portion 3 is eccentric and tilted with respect to the first reference axis X, the multiple fingers 32 can be opened and closed appropriately.

[0152] The gripping portion 3 has a base 31, a plurality of fingers 32 supported by the base 31, and an operating mechanism 33 that opens and closes the plurality of fingers 32. The opening and closing drive mechanism 8 includes a first motor 81 that generates a driving force, and an opening and closing shaft 84 that extends about a first reference axis X and is rotated around the first reference axis X by the driving force of the first motor 81. The transmission mechanism 5 includes a first joint 51 that connects the opening and closing shaft 84 and the operating mechanism 33. The connecting mechanism 4 includes an eccentric mechanism 41. The first joint 51 transmits the rotation of the opening and closing shaft 84 to the operating mechanism 33 in a state where the second reference axis Y is eccentric with respect to the first reference axis X.

[0153] According to this configuration, the opening / closing drive mechanism 8 rotates the opening / closing shaft 84 around the first reference axis X. The opening / closing shaft 84 is connected to the operating mechanism 33 of the gripper 3 via the first joint 51 of the transmission mechanism 5. As a result, even if the second reference axis Y is eccentric with respect to the first reference axis X, the rotation of the opening / closing shaft 84 around the first reference axis X is transmitted to the operating mechanism 33. As a result, the multiple fingers 32 can be opened and closed appropriately.

[0154] The first joint 51 includes a ball coupling. More specifically, the first joint 51 includes a first ball coupling 52 and a second ball coupling 53. The first ball coupling 52 and the second ball coupling 53 are each a type of universal joint.

[0155] According to this configuration, the eccentricity and angular deviation between the first reference axis X and the second reference axis Y can be absorbed by the first ball coupling 52 and the second ball coupling 53. In other words, the first ball coupling 52 and the second ball coupling 53 can transmit the rotation about the first reference axis X to the grip part 3 as a rotation about the second reference axis Y.

[0156] The operating mechanism 33 also has a plurality of links 36 connected to the plurality of fingers 32, a feed screw 37 extending about the second reference axis Y and rotating around the second reference axis Y, and a block 38 threadedly engaged with the feed screw 37 and connected to the plurality of links 36, and the first joint 51 connects the opening / closing shaft 84 and the feed screw 37.

[0157] According to this configuration, the operating mechanism 33 has a plurality of links 36 and is a so-called link mechanism. The plurality of links 36 are operated by rotation of the feed screw 37, opening and closing the plurality of fingers 32. The feed screw 37 rotates around the second reference axis Y. An opening / closing shaft 84 is connected to the feed screw 37 via the first joint 51. Therefore, even if the gripping portion 3 is eccentric or inclined with respect to the first reference axis X, the first joint 51 can appropriately transmit the rotation of the opening / closing shaft 84 to the feed screw 37.

[0158] The hand body 2 also has a rotation mechanism 7 that rotates the gripping portion 3 around the second reference axis Y, and the connecting mechanism 4 is connected to the rotation mechanism 7.

[0159] According to this configuration, the rotation mechanism 7 rotates the connecting mechanism 4, thereby rotating the gripping portion 3 around the second reference axis Y. Furthermore, by providing the rotation mechanism 7 in the hand body 2, the weight of the gripping portion 3 can be reduced.

[0160] Furthermore, the connecting mechanism 4 transmits the driving force of the rotation mechanism 7 to the gripping portion 3 in a state in which the second reference axis Y is eccentric or inclined with respect to the first reference axis X.

[0161] According to this configuration, the gripping unit 3 can be rotated around the second reference axis Y while the second reference axis Y remains eccentric or tilted relative to the first reference axis X. In other words, the connecting mechanism 4 allows for eccentricity or an angular deviation between the first reference axis X and the second reference axis Y, and allows the gripping unit 3 to rotate around the second reference axis Y. In other words, the connecting mechanism 4 can both rotate the gripping unit 3 by the rotation mechanism 7 arranged in the hand main body 2 and support the eccentric or tiltable gripping unit 3.

[0162] The connecting mechanism 4 also includes an eccentric mechanism 41, which includes a rolling body 43 interposed between the hand body 2 and the gripping portion 3, and the rolling of the rolling body 43 moves the gripping portion 3 in an eccentric direction relative to the first reference axis X.

[0163] According to this configuration, the rolling of the rolling elements 43 allows the grip portion 3 to move smoothly in the eccentric direction.

[0164] Specifically, the rotation mechanism 7 has a second motor 61 that generates a driving force, and a rotating shaft 71 that extends around the first reference axis X and is rotated around the first reference axis X by the driving force of the second motor 61, and the connecting mechanism 4 includes an eccentric mechanism 41 that connects the rotating shaft 71 and the gripping portion 3 and has a second joint 45 that transmits the rotation of the rotating shaft 71 to the gripping portion 3 with the second reference axis Y eccentric to the first reference axis X.

[0165] According to this configuration, the rotation mechanism 7 rotates the rotation shaft 71 around the first reference axis X. The rotation shaft 71 is connected to the connecting mechanism 4. The second joint 45 of the connecting mechanism 4 transmits the rotation of the rotation shaft 71 around the first reference axis X to the gripping unit 3, even if the second reference axis Y is eccentric with respect to the first reference axis X. As a result, the gripping unit 3 can be rotated around the second reference axis Y.

[0166] The second coupling 45 is an Oldham coupling.

[0167] According to this configuration, the second joint 45 can be easily realized by an Oldham coupling, which is a common coupling.

[0168] The rotation mechanism 7 also has a second motor 61 that generates a driving force, and a rotating shaft 71 that extends around the first reference axis X and is rotated around the first reference axis X by the driving force of the second motor 61. The connecting mechanism 4 includes a tilting mechanism 47, which connects the rotating shaft 71 to the gripping portion 3 and has a third joint 48 that transmits the rotation of the rotating shaft 71 to the gripping portion 3 with the second reference axis Y inclined to the first reference axis X.

[0169] According to this configuration, the rotation mechanism 7 rotates the rotation shaft 71 around the first reference axis X. The rotation shaft 71 is connected to the connection mechanism 4. The third joint 48 of the connection mechanism 4 transmits the rotation of the rotation shaft 71 around the first reference axis X to the gripping unit 3, even when the second reference axis Y is inclined with respect to the first reference axis X. As a result, the gripping unit 3 can be rotated around the second reference axis Y.

[0170] The third joint 48 is a universal joint.

[0171] According to this configuration, the third joint 48 can be easily realized by a universal joint, which is a common joint.

[0172] The hand 100 further includes a locking mechanism 9 that restricts the operation of the connecting mechanism 4 .

[0173] According to this configuration, the operation of the connecting mechanism 4 can be restricted by the locking mechanism 9. In other words, the hand 100 can switch the gripper 3 between a state in which it can be decentered or tilted and a state in which it cannot be decentered or tilted. By making the gripper 3 decenterable or tiltable, as described above, it is possible to perform work using the gripper 3 while absorbing positional deviations of the gripper 3. On the other hand, by making the gripper 3 non-decenterable or non-tiltable, it is possible to perform work using the gripper 3 with high positional accuracy.

[0174] Furthermore, the locking mechanism 9 restricts the operation of the connecting mechanism 4 when the first reference axis X and the second reference axis Y are aligned on a straight line.

[0175] According to this configuration, in the restrained state by the locking mechanism 9, the position of the hand 100 is controlled based on the first reference axis X of the hand main body 2, which inevitably makes it possible to control the position of the second reference axis Y of the gripper 3. Furthermore, when a driving force for rotation around the first reference axis X is generated in the restrained state by the locking mechanism 9, the gripper 3 can be rotated with the second reference axis Y and the first reference axis X coinciding with each other.

[0176] In addition, the hand main body 2 has a linear movement mechanism 6 that moves the connecting mechanism 4 in a linear direction relative to the hand main body 2 in the direction of the first reference axis X, and the locking mechanism 9 has a first engagement portion 91 provided on the hand main body 2 and a second engagement portion 92 provided on the gripping portion 3, and restricts the operation of the connecting mechanism 4 by engagement between the first engagement portion 91 and the second engagement portion 92, while releasing the restriction on the operation of the connecting mechanism 4 by disengaging the first engagement portion 91 from the second engagement portion 92, and the second engagement portion 92 is switched between engagement and disengagement with the first engagement portion 91 by the linear movement of the connecting mechanism 4 by the linear movement mechanism 6.

[0177] According to this configuration, the locking mechanism 9 switches the restraint of the connecting mechanism 4 by engaging and disengaging the first engaging portion 91 and the second engaging portion 92. Meanwhile, the hand main body 2 has a rectilinear mechanism 6 that moves the connecting mechanism 4 (i.e., the gripper 3) in a straight line in the direction of the first reference axis X. The locking mechanism 9 switches the engagement and disengagement of the first engaging portion 91 and the second engaging portion 92 using the rectilinear mechanism 6. Therefore, there is no need to provide a separate drive mechanism for operating the locking mechanism 9. As a result, the configuration of the hand 100 can be simplified.

[0178] Furthermore, the hand 100 further includes a buffer mechanism 10 that absorbs the force acting on the gripper 3 in the direction of the first reference axis X.

[0179] According to this configuration, when an excessive force acts on the gripper 3 in the direction of the first reference axis X, such force can be absorbed by the buffer mechanism 10. As a result, the precision of the position control of the gripper 3 in the direction of the first reference axis X can be relaxed.

[0180] The gripping portion 3 also has an operating mechanism 33 that includes a base 31, a plurality of fingers 32 supported by the base 31, and a plurality of links 36 connected to the plurality of fingers 32, and that opens and closes the plurality of fingers 32, and a connecting mechanism 4 connects the base 31 to the hand body 2.

[0181] With this configuration, the hand 100 does not allow the gripper 3 to be eccentric or tiltable with respect to the first reference axis X due to play between components such as the operating mechanism 33 and the link 36 or the rigidity of the components themselves. The hand 100 supports the gripper 3 by the connecting mechanism 4 between the hand body 2 and the gripper 3 so that the gripper 3 can be eccentric or tiltable with respect to the first reference axis X. Therefore, with the hand 100, the eccentricity or tilt of the gripper 3 can be appropriately designed and managed, rather than being left to chance.

[0182] The robot system 1000 also includes a robot arm 120, a hand 100 connected to the robot arm 120, and a control device 130 that controls the robot arm 120 and the hand 100. The hand 100 has a hand main body 2 on which a predetermined first reference axis X is defined, a gripping portion 3 on which a predetermined second reference axis Y is defined and which grips a workpiece W1, and a connecting mechanism 4 that connects the gripping portion 3 to the hand main body 2. The connecting mechanism 4 includes at least one of an eccentric mechanism 41 that supports the gripping portion 3 so that the second reference axis Y is eccentric with respect to the first reference axis X, and a tilting mechanism 47 that supports the gripping portion 3 so that the second reference axis Y is tiltable with respect to the first reference axis X. The control device 130 causes the robot arm 120 and the hand 100 to perform an insertion operation of inserting the workpiece W1 gripped by the hand 100 into a predetermined hole H.

[0183] According to this configuration, an insertion operation is performed using the hand 100 to insert the workpiece W1 into the hole H. The hand 100 is supported by the connecting mechanism 4 including at least one of the eccentric mechanism 41 and the tilting mechanism 47. Therefore, even if the positioning of the workpiece W1 with respect to the hole H is not performed precisely, the connecting mechanism 4 can make the gripping portion 3 eccentric or tilt with respect to the first reference axis X, thereby smoothly performing the insertion operation of the workpiece W1 into the hole H.

[0184] Furthermore, the control device 130 causes the workpiece W1 gripped by the gripping unit 3 to be inserted into the hole H in a state in which the second reference axis Y is eccentric or inclined with respect to the axis N of the hole H.

[0185] According to this configuration, the workpiece W1 is inserted into the hole H while being slightly misaligned from the hole H. In this case, the workpiece W1 is guided by the opening edge of the hole H and attempts to fit into the hole H. At this time, since the gripping portion 3 is eccentric or tiltable with respect to the first reference axis X, the posture of the workpiece W1 can be freely changed, and the workpiece W1 fits smoothly into the hole H.

[0186] Furthermore, the hand body 2 has a rotation mechanism 7 connected to the connecting mechanism 4 and rotating the gripping portion 3 around the second reference axis Y, and the connecting mechanism 4 includes a tilting mechanism 47 and transmits the driving force of the rotation mechanism 7 to the gripping portion 3 in a state where the second reference axis Y is tilted with respect to the first reference axis X, and the control device 130 inserts the workpiece W1 into the hole H by operating the rotation mechanism 7 from a state where the workpiece W1 gripped by the gripping portion 3 is brought into point contact with the opening edge of the hole H and the second reference axis Y is tilted with respect to the axis N of the hole H.

[0187] According to this configuration, the first reference axis X and the second reference axis Y are tilted relative to the axis N of the hole H, and the workpiece W1 is rotated about the second reference axis Y from a state in which the workpiece W1 is in point contact with the edge of the hole H. This rotational and tilted insertion is performed to insert the workpiece W1 into the hole H. The rotational and tilted insertion guides the workpiece W1 to the edge of the hole H, allowing the workpiece W1 to be smoothly introduced into the hole H. The connecting mechanism 4 supports the gripper 3 so that it can tilt relative to the first reference axis X, and can transmit the driving force of the rotation mechanism 7 to the gripper 3 with the second reference axis Y tilted relative to the first reference axis X. Therefore, as the workpiece W1 is introduced into the hole H, the gripper 3 can change its posture so that the second reference axis Y coincides with the axis N of the hole H, while continuing to rotate about the second reference axis Y. This operation of the gripper 3 can be achieved without moving the hand main body 2, thanks to the flexible support of the gripper 3 by the connecting mechanism 4.

[0188] In addition, the connecting mechanism 4 further includes an eccentric mechanism 41, and transmits the driving force of the rotation mechanism 7 to the gripping unit 3 with the second reference axis Y eccentric with respect to the first reference axis X. The control device 130 partially inserts the workpiece W1 gripped by the gripping unit 3 into the hole H, and then operates the robot arm 120 so that the first reference axis X is parallel to the axis N of the hole H, and then operates the rotation mechanism 7 to further insert the workpiece W1 into the hole H.

[0189] According to this configuration, after the workpiece W1 is partially inserted into the hole H by rotational and tilted insertion, the robot arm 120 moves so that the first reference axis X is parallel to the axis N of the hole H. Because the workpiece W1 is inserted into the hole H, the second reference axis Y is aligned with the axis N. Therefore, the first reference axis X is aligned with or parallel to the second reference axis Y. The connecting mechanism 4 supports the gripper 3 eccentrically with respect to the first reference axis X and can transmit the driving force of the rotation mechanism 7 to the gripper 3 with the second reference axis Y eccentric with respect to the first reference axis X. Therefore, the hand 100 can rotate the gripper 3 around the second reference axis Y by the rotation mechanism 7 with the second reference axis Y aligned with or eccentric to the first reference axis X. As a result, the workpiece W1 is inserted into the hole H while rotating around the axis N. At this time, since the first reference axis X is aligned with or parallel to the axis N, it is possible to reduce the amount of workpiece W1 that gets stuck in the hole H compared to when the first reference axis X and the axis N are inclined. As a result, the workpiece W1 can be inserted smoothly into the hole H.

[0190] Furthermore, the hand 100 further includes a locking mechanism 9 that restricts the operation of the tilting mechanism 47, and the control device 130 operates the robot arm 120 to bring the workpiece W1 held by the gripping portion 3 into point contact with the opening edge of the hole H with the tilting mechanism 47 restricted by the locking mechanism 9 and the second reference axis Y tilted relative to the axis N of the hole H, and then operates the rotation mechanism 7 to insert the workpiece W1 into the hole H with the tilting mechanism 47 no longer restricted by the locking mechanism 9.

[0191] According to this configuration, by restricting the operation of the tilting mechanism 47 with the locking mechanism 9 and making it impossible to tilt the gripping part 3 with respect to the first reference axis X, it is possible to realize with high positional accuracy the operation of bringing the workpiece W1 into point contact with the opening edge of the hole H with the second reference axis Y tilted with respect to the axis N of the hole H. Then, when starting to insert the workpiece W1 into the hole H, the restriction of the tilting mechanism 47 by the locking mechanism 9 is released, thereby enabling the workpiece W1 to be smoothly inserted into the hole H as described above.

[0192] Other Embodiments As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology of the present disclosure is not limited to this and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above embodiment can be combined to create new embodiments. Furthermore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately determining that these non-essential components are essential.

[0193] For example, the hand 100 does not have to be connected to the robot arm 120. The hand 100 may be applied to a dedicated machine or the like instead of the robot 110.

[0194] The operation performed by the hand 100 is not limited to the insertion operation, but may be an operation of simply picking up a component, an operation of placing a component in a predetermined location, or the like.

[0195] The insertion operation may not only be a simple insertion of the workpiece W1 into the hole H, but may also be a press-fitting of the workpiece W1 into the hole H or a screwing of the workpiece W1 into a screw hole. Furthermore, the insertion operation is not limited to rotational and tilted insertion. In other words, when inserting the workpiece W1 into the hole H, the workpiece W1 may be inserted into the hole H from a state in which the second reference axis Y and the axis N of the hole H are parallel or aligned on a straight line. Alternatively, when inserting the workpiece W1 into the hole H, the workpiece W1 may be inserted into the hole H from a state in which the workpiece W1 is in line contact or multiple-point contact with the opening edge of the hole H.

[0196] In the above-described insertion operation, the robot system 1000 performs an operation of introducing the workpiece W1 into the hole H by rotational and tilted insertion, and then performs a further insertion operation with the first reference axis X parallel to the axis N of the hole H. However, this is not limiting. For example, after the introduction operation, the insertion of the workpiece W1 into the hole H may be continued with the first reference axis X tilted to the axis N of the hole H.

[0197] The insertion operation may also be an operation of inserting a workpiece into a hole whose axis extends horizontally. In this case, the locking mechanism 9 is particularly effective. Specifically, the hand 100 assumes a position in which the first reference axis X extends substantially horizontally. Compared to when the first reference axis X is oriented substantially vertically, the gripping unit 3 is more likely to become eccentric and tilted relative to the first reference axis X due to its own weight and the load of the workpiece. By restricting the operation of the connecting mechanism 4 with the locking mechanism 9, the eccentricity and tilting of the gripping unit 3 can be limited. This allows the workpiece to be aligned with high precision.

[0198] The hand 100 may omit at least one of the linear movement mechanism 6 and the rotation mechanism 7. For example, the entire hand 100 may be moved linearly in the direction of the first reference axis X by the robot arm 120, or may be rotated around the first reference axis X.

[0199] The connecting mechanism 4 may be configured to either decenter or tilt the second reference axis Y of the grip portion 3 relative to the first reference axis X. In other words, the connecting mechanism 4 may be configured to either decenter or tilt the grip portion 3.

[0200] The mechanism for eccentrically positioning the second reference axis Y of the gripping part 3 relative to the first reference axis X is not limited to the configuration of the eccentric mechanism 41. For example, the eccentric mechanism 41 may include only one of the second joint 45, the eccentric body 42, the rolling body 43, and the first disk 71c.

[0201] The second joint 45 is not limited to an Oldham coupling. The second joint 45 may be any coupling that transmits rotation between two eccentric shafts. For example, the second joint 45 may be a Schmidt coupling or a pin joint that transmits rotation by fitting a pin attached to a disk on one shaft into a round hole on a disk on the other shaft.

[0202] The third joint 48 is not limited to a universal joint. The third joint 48 may be any joint that transmits rotation between two inclined axes (i.e., two axes having an angle of deflection). For example, the third joint 48 may be a flexible joint, a torque coil, or a ball joint.

[0203] The operating mechanism 33 of the gripper 3 is not limited to a link mechanism. The operating mechanism 33 may be any mechanism that is driven by the rotation of the opening / closing shaft 84 to open and close the fingers 32. For example, the operating mechanism 33 may be a slider-type or rack-and-pinion-type mechanism that opens and closes the fingers 32.

[0204] The first joint 51 is not limited to the first ball coupling 52 and the second ball coupling 53. The first joint 51 may be any joint that transmits rotation between two eccentric or inclined shafts. For example, the first joint 51 may be one or more universal joints, flexure joints, torque coils, ball joints, Oldham couplings, Schmidt couplings, or pin joints.

[0205] The hand 100 does not necessarily have to have the locking mechanism 9. The locking mechanism 9 is not limited to the configuration described above. The first engaging portion 91 and the second engaging portion 92 need only be configured to engage with each other, and are not limited to being cylindrical. The engagement and disengagement of the first engaging portion 91 and the second engaging portion 92 may be switched by a separate drive mechanism rather than by the linear movement mechanism 6. Alternatively, the locking mechanism 9 may restrict the operation of the connecting mechanism 4 by pressing the gripping portion 3 against another member such as the hand body 2.

[0206] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, application-specific integrated circuits (ASICs), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or processor. [Explanation of symbols]

[0207] 1000 Robot System 100 hands 120 Robot Arm 130 Control device 2 Hand body 3 Gripping part 31 Base 32 fingers 33 Operating mechanism 36 Links 37 Lead screw 38 blocks 4 Connection mechanism 41 Eccentric mechanism 43 Rolling elements 45 Second joint 47 Tilt mechanism 48 Third joint 5 Transmission mechanism 51 First joint 52 First ball coupling 53 Second ball coupling 6. Straight-line mechanism 61 Second motor (rotation drive source) 7 Rotation mechanism 71 Rotating shaft 8 Opening and closing drive mechanism 81 First motor (opening / closing drive source) 84 Opening and closing shaft 9 Locking mechanism 91 First engagement portion 92 Second engagement portion 10 Buffer mechanism X 1st reference axis Y Second Reference Axis

Claims

1. a hand body in which a predetermined first reference axis is defined; a gripping unit that defines a predetermined second reference axis and grips a workpiece; a connecting mechanism that connects the gripping portion to the hand body, The connecting mechanism is a hand including at least one of an eccentric mechanism that supports the gripping portion so that the second reference axis is freely eccentric with respect to the first reference axis, and a tilting mechanism that supports the gripping portion so that the second reference axis is freely tiltable with respect to the first reference axis.

2. The hand according to claim 1, The hand wherein the coupling mechanism includes both the eccentric mechanism and the tilt mechanism.

3. The hand according to claim 1 or 2, the hand body has an opening / closing drive mechanism that opens and closes the gripping portion, the connecting mechanism has a transmission mechanism that transmits the driving force of the opening / closing drive mechanism to the gripping portion, The transmission mechanism transmits the driving force of the opening / closing drive mechanism to the gripping portion in a state in which the second reference axis is eccentric or inclined with respect to the first reference axis.

4. The hand according to claim 3, the gripping portion has a base, a plurality of fingers supported by the base, and an operating mechanism for opening and closing the plurality of fingers, the opening / closing drive mechanism includes an opening / closing drive source that generates a drive force, and an opening / closing shaft that extends about the first reference axis and is rotated about the first reference axis by the drive force of the opening / closing drive source, the transmission mechanism includes a first joint that connects the opening / closing shaft and the operating mechanism; the coupling mechanism includes the tilt mechanism, The first joint is a hand that transmits rotation of the opening / closing shaft to the operating mechanism in a state where the second reference axis is inclined with respect to the first reference axis.

5. The hand according to claim 4, the coupling mechanism further includes the eccentric mechanism, The first joint is a hand that transmits rotation of the opening / closing shaft to the operating mechanism in a state in which the second reference axis is eccentric with respect to the first reference axis.

6. The hand according to claim 3, the gripping portion has a base, a plurality of fingers supported by the base, and an operating mechanism for opening and closing the plurality of fingers, the opening / closing drive mechanism includes an opening / closing drive source that generates a drive force, and an opening / closing shaft that extends about the first reference axis and is rotated about the first reference axis by the drive force of the opening / closing drive source, the transmission mechanism includes a first joint that connects the opening / closing shaft and the operating mechanism; the coupling mechanism includes the eccentric mechanism, The first joint is a hand that transmits rotation of the opening / closing shaft to the operating mechanism in a state in which the second reference axis is eccentric with respect to the first reference axis.

7. The hand according to any one of claims 4 to 6, The first joint may include a universal joint, a flexible joint, a torque coil, a ball coupling, or a ball joint.

8. The hand according to any one of claims 4 to 7, the operating mechanism includes a plurality of links connected to the plurality of fingers, a feed screw that extends about the second reference axis and rotates around the second reference axis, and a block that is screwed onto the feed screw and to which the plurality of links are connected, The first joint is a hand that connects the opening / closing shaft and the feed screw.

9. The hand according to any one of claims 1 to 8, the hand body has a rotation mechanism that rotates the gripping portion around the second reference axis, The connecting mechanism is a hand connected to the rotation mechanism.

10. The hand according to claim 9, The connecting mechanism transmits the driving force of the rotation mechanism to the gripping portion in a state in which the second reference axis is eccentric or inclined with respect to the first reference axis.

11. The hand according to claim 9 or 10, the coupling mechanism includes the eccentric mechanism, The eccentric mechanism includes a rolling element interposed between the hand body and the gripping portion, and the rolling of the rolling element moves the gripping portion in an eccentric direction relative to the first reference axis.

12. The hand according to claim 10 or 11, the rotation mechanism includes a rotation drive source that generates a drive force, and a rotation shaft that extends about the first reference axis and is rotated about the first reference axis by the drive force of the rotation drive source, the coupling mechanism includes the eccentric mechanism, The eccentric mechanism is a hand having a second joint that connects the rotating shaft and the gripping portion and transmits rotation of the rotating shaft to the gripping portion in a state where the second reference axis is eccentric with respect to the first reference axis.

13. The hand according to claim 12, The second joint may include an Oldham joint, a Schmidt joint, or a pin joint.

14. The hand according to claim 10 or 11, the rotation mechanism includes a rotation drive source that generates a drive force, and a rotation shaft that extends about the first reference axis and is rotated about the first reference axis by the drive force of the rotation drive source, the coupling mechanism includes the tilt mechanism, The tilting mechanism is a hand having a third joint that connects the rotating shaft and the gripping portion and transmits rotation of the rotating shaft to the gripping portion in a state where the second reference axis is tilted with respect to the first reference axis.

15. The hand according to claim 14, The third joint is a universal joint, a flexible joint, a torque coil, or a ball joint.

16. 16. The hand according to claim 1, The hand further includes a locking mechanism that restricts the operation of the connecting mechanism.

17. 17. The hand of claim 16, The locking mechanism restricts the operation of the connecting mechanism when the first reference axis and the second reference axis are aligned on a straight line.

18. 18. The hand according to claim 16 or 17, the hand body has a rectilinear mechanism that causes the gripping portion to move linearly relative to the hand body in the direction of the first reference axis, the locking mechanism has a first engaging portion provided on the hand body and a second engaging portion provided on the gripping portion, and restricts the operation of the connecting mechanism by engaging the first engaging portion with the second engaging portion, and releases the restriction on the operation of the connecting mechanism by disengaging the first engaging portion from the second engaging portion; The second engagement portion is a hand that switches between engagement and disengagement with the first engagement portion by linear movement of the gripping portion by the linear movement mechanism.

19. 19. The hand according to any one of claims 1 to 18, The hand further includes a buffer mechanism that absorbs a force acting on the gripping portion in the direction of the first reference axis.

20. The hand according to any one of claims 1 to 3, the gripping portion has a base, a plurality of fingers supported by the base, and an operating mechanism including a plurality of links connected to the plurality of fingers, and causing the plurality of fingers to open and close; The connecting mechanism is a hand that connects the base to the hand body.

21. A robotic arm, a hand connected to the robot arm; a control device for controlling the robot arm and the hand, The hand a hand body in which a predetermined first reference axis is defined; a gripping unit that defines a predetermined second reference axis and grips a workpiece; a connecting mechanism that connects the gripping portion to the hand body, the connecting mechanism includes at least one of an eccentric mechanism that supports the gripping portion so that the second reference axis is freely eccentric with respect to the first reference axis, and a tilting mechanism that supports the gripping portion so that the second reference axis is freely tiltable with respect to the first reference axis, The control device is a robot system that causes the robot arm and the hand to perform an insertion operation of inserting the workpiece grasped by the hand into a predetermined hole.

22. 22. The robotic system according to claim 21, The control device is a robot system that inserts the workpiece gripped by the gripping portion into the hole in a state in which the second reference axis is eccentric or inclined with respect to the axis of the hole.

23. 23. The robotic system according to claim 22, the hand body has a rotation mechanism connected to the connection mechanism and configured to rotate the gripper around the second reference axis; the coupling mechanism includes the tilting mechanism and transmits the driving force of the rotation mechanism to the gripping portion in a state in which the second reference axis is tilted with respect to the first reference axis; The control device is a robot system that inserts the workpiece into the hole by operating the rotation mechanism from a state in which the workpiece gripped by the gripping portion is brought into point contact with the opening edge of the hole and the second reference axis is inclined with respect to the axis of the hole.

24. 24. The robotic system according to claim 23, the connecting mechanism further includes the eccentric mechanism, and transmits the driving force of the rotation mechanism to the gripping portion in a state in which the second reference axis is eccentric with respect to the first reference axis; The control device partially inserts the workpiece gripped by the gripping portion into the hole, and then operates the robot arm so that the first reference axis is parallel to the axis of the hole, and then operates the rotation mechanism to further insert the workpiece into the hole.

25. 25. The robot system according to claim 23 or 24, the hand further includes a locking mechanism that restricts the operation of the tilting mechanism; The control device operating the robot arm so that the workpiece gripped by the gripping portion is brought into point contact with the opening edge of the hole in a state in which the tilting mechanism is constrained by the locking mechanism and the second reference axis is tilted with respect to the axis of the hole; A robot system that inserts the workpiece into the hole by operating the rotation mechanism while the tilt mechanism is released from the constraint of the locking mechanism.

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