Robot, zero-point calibration fixture, zero-point calibration system and zero-point calibration method

Abstract

A robot is provided with V-grooves (12, 22) or V-projections respectively on two components (3, 4) that form a joint axis and are supported so as to be relatively movable. The V-grooves (12, 22) have two inclined inner surfaces that intersect at a linear groove bottom extending in a direction orthogonal to the moving direction, and the V-projections have two inclined outer surfaces that intersect at a linear edge extending in a direction orthogonal to the moving direction. When the two components (3, 4) of the joint axis are arranged at a predetermined operating position, the V-grooves (12, 22) or the V-projections are arranged at positions where the groove bottoms, the edges, or the groove bottom and the edge coincide with each other.

Description

Technical Field

[0001] The present invention relates to a robot, a zero-point calibration jig, a zero-point calibration system, and a zero-point calibration method. Background Art

[0002] Known robots are as follows: On two members rotatably connected via a joint axis, linear marks for alignment are respectively provided (for example, refer to Patent Document 1).

[0003] In a state where zero-point calibration of the joint axis is performed, by making the linear marks provided on the two members of the joint axis coincide in advance, after replacement of the motor or reducer of the joint axis, the joint axis can be easily restored to the origin position using the marks.

[0004] In addition, a known zero-point calibration method is as follows: A jig is mounted on a base having a reference plane, and the distance between a movable plane of a movable part rotatably connected about a rotation axis and the reference plane is measured using a measuring instrument (for example, refer to Patent Document 2).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-251365

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2014-46399 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, although the linear marks are effective for easy restoration of the origin position, it is difficult to accurately restore.

[0011] On the other hand, although the origin position can be accurately restored using a jig and a measuring instrument as in Patent Document 2, it is necessary to separately provide marks for easy restoration such as lines, and it takes cost and labor to machine parts for high-precision mounting of the jig.

[0012] Therefore, it is desired to simply and inexpensively achieve both easy restoration and accurate restoration of the origin position.

[0013] Means for Solving the Problems

[0014] One aspect of the present invention is a robot. On two components that form a joint axis and are supported to be relatively movable, V-grooves or V-protrusions are respectively provided. The V-groove has two inclined inner surfaces intersecting at a linear groove bottom extending in a direction orthogonal to the moving direction. The V-protrusion has two inclined outer surfaces intersecting at a linear edge extending in a direction orthogonal to the moving direction. When the two components of the joint axis are arranged at a predetermined operating position, the V-groove or the V-protrusion is arranged at a position where the groove bottoms, the edges, or the groove bottom and the edge coincide with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. is an overall structure diagram showing an example of a robot according to an embodiment of the present invention.

[0016] Figure 2 FIG. shows the two zero-point calibration support surfaces provided on Figure 1 a robot of the second rotary joint axis, as an example, in a perspective view.

[0017] Figure 3 FIG. shows the zero-point calibration support surface of a rotating body provided on Figure 2 and a first jig positioned on the zero-point calibration support surface, as an example, in a perspective view.

[0018] Figure 4 FIG. shows a bracket of a second jig positioned on the zero-point calibration support surface of an arm provided on Figure 2 a robot, as an example, in a perspective view.

[0019] Figure 5 FIG. shows the zero-point calibration support surface of an arm provided on Figure 2 a robot and a second jig positioned on the zero-point calibration support surface, as an example, in a perspective view.

[0020] Figure 6 FIG. shows a zero-point calibration jig according to an embodiment of the present invention, which is arranged in a positioned state on Figure 2 two zero-point calibration support surfaces, as an example, in a perspective view.

[0021] Figure 7 FIG. is a flowchart showing a part of a zero-point calibration method according to an embodiment of the present invention.

[0022] Figure 8 FIG. is a flowchart showing Figure 7 the distance measurement process in the zero-point calibration method.

[0023] Figure 9 FIG. is a flowchart showing a part of Figure 7 the zero-point calibration method.

[0024] Figure 10 is a perspective view showing a deformation example of the support surface for zero-point calibration. Figure 2 of the

[0025] Figure 11 is a perspective view showing an example of a zero-point calibration jig Figure 10 configured in a positioning state with two support surfaces for zero-point calibration Figure 6 of the

[0026] Figure 12 is a perspective view showing Figure 3 a deformation example of the support surface for zero-point calibration and the first jig

[0027] Figure 13 is a perspective view showing Figure 5 a deformation example of the support surface for zero-point calibration and the second jig

[0028] Figure 14 is a perspective view showing a deformation example of the concave portion of the first jig provided on Figure 12 or the second jig provided on Figure 13 the

[0029] Figure 15 is a perspective view showing a deformation example of the convex portion of the first jig provided on Figure 3 or the second jig provided on Figure 5 the Detailed implementation mode

[0030] Hereinafter, a robot 1, a zero-point calibration jig 50, a zero-point calibration system, and a zero-point calibration method according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0031] The zero-point calibration system of the present embodiment includes a robot 1 and a zero-point calibration jig 50.

[0032] As Figure 1 shown, the robot 1 of the present embodiment is, for example, a vertical articulated robot having six rotary joint axes (joint axes). The robot 1 includes a base (component) 2, a rotating body (component) 3, and a first arm (component) 4. The base 2 is provided on the ground, the rotating body 3 is supported by the base 2 so as to be rotatable about a vertical first axis A, and the first arm 4 is supported by the rotating body 3 so as to be rotatable about a horizontal second axis B. In addition, the robot 1 includes a second arm (component) 5 and a three-axis wrist unit 6. The second arm 5 is supported by the first arm 4 so as to be rotatable about a third axis C parallel to the second axis B, and the three-axis wrist unit 6 is disposed at the front end of the second arm 5.

[0033] The wrist unit 6 includes a first wrist element (component) 7, and the first wrist element 7 is supported by the second arm 5 so as to be rotatable about a fourth axis D disposed in a plane orthogonal to the third axis C. Further, the wrist unit 6 includes a second wrist element (component) 8, and the second wrist element (component) 8 is supported by the first wrist element 7 so as to be rotatable about a fifth axis E orthogonal to the fourth axis D. Moreover, the wrist unit 6 includes a third wrist element (component) 9, and the third wrist element 9 is supported by the second wrist element 8 so as to be rotatable about a sixth axis F orthogonal to the fifth axis E and intersecting the third axis C.

[0034] Each rotary joint axis includes two components that can rotate relative to each other. For example, the first rotary joint axis includes a base 2 and a rotating body 3 that can rotate relative to each other. Further, the second rotary joint axis includes the rotating body 3 and the first arm 4 that can rotate relative to each other. In addition, the third rotary joint axis includes the first arm 4 and the second arm 5 that can rotate relative to each other.

[0035] The fourth rotary joint axis includes the second arm 5 and the first wrist element 7 that can rotate relative to each other. The fifth rotary joint axis includes the first wrist element 7 and the second wrist element 8 that can rotate relative to each other. And the sixth rotary joint axis includes the second wrist element 8 and the third wrist element 9 that can rotate relative to each other.

[0036] Two components 2, 3, 4, 5, 7, 8, 9 that constitute each rotary joint axis are respectively provided with zero-point calibration support surfaces 10 at positions adjacent to the boundaries of the two components 2, 3, 4, 5, 7, 8, 9. The zero-point calibration support surfaces 10, 20 of each rotary joint axis are the same. Therefore, here, the zero-point calibration support surfaces 10, 20 provided on the rotating body 3 and the first arm 4 that constitute the second rotary joint axis are taken as examples for description.

[0037] As Figure 2 shown, the zero-point calibration support surface 10 of the rotating body 3 is provided on the cylindrical outer peripheral surface centered on the second axis B and adjacent to the boundary with the first arm 4. Further, the zero-point calibration support surface 20 of the first arm 4 is provided on the side surface orthogonal to the second axis B and adjacent to the boundary with the rotating body 3, and is provided at a position farther from the second axis B in the radial direction than the zero-point calibration support surface 10 of the rotating body 3.

[0038] As Figure 3As shown, the zero-point calibration support surface 10 of the rotating body 3 includes a support surface portion 11 and a V-groove (recess) 12. The support surface portion 11 is formed by a plane extending along the tangent direction of a circle centered on the second axis B. The V-groove (recess) 12 is formed by cutting off a part of the support surface portion 11. The V-groove 12 has an inclined inner surface 13, and the inclined inner surface 13 is composed of two planes, and these two planes intersect at a predetermined angle, for example, an angle of 90°, at a linear groove bottom 12a extending parallel to the second axis B. The moving direction of the first arm 4 relative to the rotating body 3 is the tangent direction of a circle centered on the second axis B, and the groove bottom 12a of the V-groove 12 extends in a direction orthogonal to the moving direction of the first arm 4.

[0039] In addition, as Figure 5 shown, the zero-point calibration support surface 20 of the first arm 4 includes a support surface portion 21 and a V-groove (recess) 22. The support surface portion 21 is formed by a plane orthogonal to the second axis B. The V-groove (recess) 22 is formed by cutting off a part of the support surface portion 21. The V-groove 22 has an inclined inner surface 23, and the inclined inner surface 23 is composed of two planes, and these two planes intersect at a predetermined angle, for example, an angle of 90°, at a linear groove bottom 22a extending in a direction orthogonal to the second axis B. The groove bottom 22a of the V-groove 22 extends in a direction orthogonal to the moving direction of the first arm 4 relative to the rotating body 3.

[0040] The zero-point calibration support surface 10 of the rotating body 3 is formed by machining the support surface portion 11 and the V-groove 12 during the machining of the components constituting the rotating body 3. The zero-point calibration support surface 20 of the first arm 4 is formed by machining the support surface portion 21 and the V-groove 22 during the machining of the components constituting the first arm 4. When the first arm 4 is arranged at the origin position relative to the rotating body 3, for example, Figure 1 at the position, the zero-point calibration support surfaces 10 and 20 of the rotating body 3 and the first arm 4 are formed at the following positions in the design values: the groove bottoms 12a and 22a of the V-grooves 12 and 22 are arranged in the same plane.

[0041] Next, the zero-point calibration jig 50 of the present embodiment will be described with reference to the drawings.

[0042] The zero-point calibration jig 50 includes a first jig 60 and a second jig 70. The first jig 60 is arranged in a positioning state on the zero-point calibration support surface 10 of one of the components 2, 3, 4, 5, 7, 8, 9 that constitute each rotary joint axis. The second jig 70 is arranged in a positioning state on the zero-point calibration support surface 20 of the other component 3, 4, 5, 7, 8, 9. In addition, the zero-point calibration jig 50 includes a dial gauge (measuring instrument) 80 fixed to the first jig 60 or the second jig 70.

[0043] Here, the zero-point calibration jig 50 for zero-point calibration of the rotating body 3 and the first arm 4 constituting the second rotary joint axis will also be described as an example.

[0044] As Figure 3 shown, the first jig 60 includes a flat main body portion 61 having a reference plane (reference surface) 60a on its surface, and a flat positioning portion 62 provided at one end of the main body portion 61 orthogonally to the main body portion 61.

[0045] On the surface of the positioning portion 62 on the side opposite to the main body portion 61, there are provided: a contact surface 63 formed by a plane that contacts the support surface portion 11 of the zero-point calibration support surface 10, and a V-shaped protrusion (convex portion) 64 that partially bulges the central portion of the contact surface 63. The V-shaped protrusion 64 has an inclined outer surface 66, and the inclined outer surface 66 is formed by two planes, and the two planes intersect at a linear edge 65 at a predetermined angle, for example, an angle of 90°, and the V-shaped protrusion 64 has a shape complementary to the V-shaped groove 12 of the zero-point calibration support surface 10. That is, when the V-shaped protrusion 64 of the first jig 60 is inserted into the V-shaped groove 12 of the zero-point calibration support surface 10 of the rotating body 3, the two inclined outer surfaces 66 of the V-shaped protrusion 64 are simultaneously in close contact with the two inclined inner surfaces 13 of the V-shaped groove 12.

[0046] The reference plane 60a is arranged to be orthogonal to the contact surface 63 and parallel to the edge 65 of the V-shaped protrusion 64.

[0047] When the V-shaped protrusion 64 of the first jig 60 is inserted into the V-shaped groove 12 of the zero-point calibration support surface 10 of the rotating body 3 and the contact surface 63 is brought into contact with the support surface portion 11, the two inclined outer surfaces 66 of the V-shaped protrusion 64 are simultaneously in close contact with the two inclined inner surfaces 13 of the V-shaped groove 12, and the contact surface 63 is in close contact with the support surface portion 11. In this state, the reference plane 60a provided on the first jig 60 is arranged in the following state: positioned at a position extending in a direction orthogonal to the support surface portion 11 and parallel to the second axis B.

[0048] By engaging the V-shaped protrusion 64 with the V-shaped groove 12, only the movement of the first jig 60 relative to the zero-point calibration support surface 10 of the rotating body 3 in the direction along the groove bottom 12a of the V-shaped groove 12 is allowed. Thus, the reference plane 60a of the first jig 60 is positioned relative to the rotating body 3. As Figure 6 shown by the arrow X in the figure, even if the first jig 60 is moved along the V-shaped groove 12 in the direction along the second axis B, the position of the reference plane 60a does not change.

[0049] As Figure 4 and Figure 5As shown, the second jig 70 includes a bracket 71 and a micrometer 80. The bracket 71 is positioned on the zero calibration support surface 20 provided on the first arm 4, and the micrometer 80 is fixed in the through hole 71a of the bracket 71.

[0050] The bracket 71 includes a positioning portion 72 for positioning on the zero calibration support surface 20 provided on the first arm 4. The positioning portion 72 has the same shape as the positioning portion 62 of the first jig 60, and includes a planar contact surface 73 that contacts the support surface portion 21 of the zero calibration support surface 20, and a V-shaped protrusion (convex portion) 74 that bulges a part of the contact surface 73 and has a shape complementary to the V-shaped groove 22 of the zero calibration support surface 20.

[0051] The micrometer 80 is a micrometer that advances and retracts the plunger 81, and is fixed to the bracket 71 in such a way that the plunger 81 advances and retracts in a direction parallel to the contact surface 73 on a plane orthogonal to the edge 75 of the V-shaped protrusion 74. In Figure 5 FIG., reference numeral 82 is a mounting fitting for mounting the micrometer 80 on the bracket 71, and reference numeral 83 is a mounting screw. The micrometer 80 can be reset at a position where the protruding amount of the front end of the plunger 81 from the bracket 71 becomes a predetermined amount.

[0052] By engaging the V-shaped protrusion 74 with the V-shaped groove 22, only the second jig 70 is allowed to move relative to the zero calibration support surface 20 of the first arm 4 in the direction along the groove bottom 22a of the V-shaped groove 22. Thus, the micrometer 80 of the second jig 70 is positioned relative to the first arm 4. And if the first jig 60 is positioned with high precision, as shown by the arrow Y in Figure 6 FIG., even if the second jig 70 is moved along the V-shaped groove 22 in a direction orthogonal to the second axis B, the protruding amount of the front end of the plunger 81 of the micrometer 80 does not change.

[0053] The first jig 60 is brought into contact with the zero calibration support surface 10 of the rotating body 3, and the second jig 70 is brought into contact with the zero calibration support surface 20 of the first arm 4. If the operating position of the first arm 4 relative to the rotating body 3 around the second axis B is adjusted, the front end of the plunger 81 of the micrometer 80 comes into contact with the reference plane 60a. Thus, the relative positional relationship (distance) between the rotating body 3 and the first arm 4 can be measured using the micrometer 80.

[0054] Next, a zero calibration method according to an embodiment of the present invention will be described.

[0055] The zero-point calibration method of this embodiment includes: First, in the state where the robot 1 has been zero-point calibrated, the above-mentioned zero-point calibration fixture 50 is used to measure the first distance. The first distance is the distance measured by a micrometer when the two components 2, 3, 4, 5, 7, 8, 9 of each rotating joint axis are arranged at the first action position.

[0056] For example, the measurement of the first distance will be described taking the second rotating joint axis as an example. As Figure 7 shown, in the state where zero-point calibration has been performed (step S0), by adjusting the rotational angle position of the first arm 4 relative to the rotating body 3, the rotating body 3 and the first arm 4 are arranged at the first action position, such as the origin position (step S1). In this state, a distance measurement process is carried out (step S2).

[0057] In the distance measurement process step of step S3, as Figure 8 shown, the first fixture 60 is arranged at the zero-point calibration support surface 10 of the rotating body 3 in a positioned state (step S21), and the second fixture 70 is arranged at the zero-point calibration support surface 20 of the first arm 4 in a positioned state (step S22). At the origin position, as Figure 2 shown, the bottom 12a of the V-groove 12 of the zero-point calibration support surface 10 of the rotating body 3 and the bottom 22a of the V-groove 22 of the zero-point calibration support surface 20 of the first arm 4 are arranged in the same plane.

[0058] When the rotating body 3 and the first arm 4 are arranged at the first action position, the front end of the plunger 81 of the micrometer 80 is pressed by the reference plane 60a of the first fixture 60, and the first distance is measured using the micrometer 80 (step S23). The measured first distance is stored in advance (step S3).

[0059] Next, by replacing the motor or reducer that drives the second rotating joint axis, in the state where zero-point calibration is lost (step S10), as Figure 9 shown, using the same method as in step S1, the second distance is measured. That is, by adjusting the rotational angle position of the first arm 4 relative to the rotating body 3, the rotating body 3 and the first arm 4 are arranged at the second action position, such as the approximate origin position (step S11).

[0060] In this state, a distance measurement process for the second distance is carried out (step S2).

[0061] Then, the difference between the measured second distance and the first distance stored in advance is calculated (step S12), and it is determined whether the difference is below a predetermined threshold (step S13).

[0062] If the difference is greater than the predetermined threshold, the process starting from step S11 is repeated. When the difference becomes below the predetermined threshold, the zero-point calibration ends.

[0063] Thus, in the robot 1, zero-point calibration jig 50, zero-point calibration system, and zero-point calibration method according to the present embodiment, zero-point calibration support surfaces 10, 20 each having a V-groove 12, 22 are provided on two components 2, 3, 4, 5, 7, 8, 9 that constitute each rotary joint axis. Thereby, by merely bringing the V-projections 64, 74 of the first jig 60 and the second jig 70 into close contact with the respective V-grooves 12, 22, the first jig 60 and the second jig 70 can be arranged in a highly accurate positioning state on the respective components 2, 3, 4, 5, 7, 8, 9, and zero-point calibration can be performed with high precision.

[0064] That is, without fixing with bolts or pins, the first jig 60 and the second jig 70 can be positioned on the respective components 2, 3, 4, 5, 7, 8, 9 by using the V-grooves 12, 22. The machining of the zero-point calibration support surfaces 10, 20 having the V-grooves 12, 22 can be performed more simply than the machining of threaded holes and pin holes. In addition, there are the following advantages: the operation of installing the first jig 60 and the second jig 70 on the respective components 2, 3, 4, 5, 7, 8, 9 can be easily performed without bolt tightening or pin driving operations.

[0065] In addition, in the present embodiment, while bringing the V-projections 64, 74 into close contact with the V-grooves 12, 22, the contact surfaces 63, 73 of the first jig 60 and the second jig 70 are brought into close contact with the support surface portions 11, 21 of the zero-point calibration support surfaces 10, 20. The positioning of the first jig 60 and the second jig 70 can be performed only by bringing the V-grooves 12, 22 into close contact with the V-projections 64, 74. In addition, there are the following advantages: by additionally utilizing the close contact between the contact surfaces 63, 73 and the support surface portions 11, 21, it is possible to easily prevent the tilting of the reference plane 60a of the first jig 60 and the position deviation of the second jig 70 by merely pressing the contact surfaces 63, 73 with a finger to the extent that they do not separate from the support surface portions 11, 21.

[0066] In addition, the robot 1 according to the present embodiment includes zero-point calibration support surfaces 10, 20, and the zero-point calibration support surfaces 10, 20 include V-grooves 12, 22 having the above functions. Therefore, as Figure 2 shown, by visually or using a camera to confirm that the bottom surfaces 12a, 22a of the V-grooves 12, 22 of the two components 2, 3, 4, 5, 7, 8, 9 are arranged in the same plane, zero-point calibration can be easily performed. That is, there are the following advantages: the bottom surfaces 12a, 22a of the V-grooves 12, 22 can be used as scribing marks.

[0067] In addition, in this embodiment, the support surfaces 10, 20 for zero point calibration, the zero point calibration fixture 50 and the zero point calibration method are explained using the second rotating joint axis as an example, but the same support surfaces 10, 20 for zero point calibration, the zero point calibration fixture 50 and the zero point calibration method can also be applied to other rotating joint axes.

[0068] That is, in the above embodiment, if Figure 2 As shown, support surfaces 10, 20 for zero point calibration are provided on the outer peripheral surface of the rotating body 3 around the second axis B constituting the second rotary joint axis and on the side surface of the first arm 4 which is orthogonal to the second axis B. The support surfaces 10, 20 for zero point calibration have V-grooves 12, 22 extending along planes orthogonal to each other.

[0069] However, the zero point calibration support surfaces 10 and 20 are not limited to Figure 2 Such a configuration can also be Figure 10 For example, in Figure 1 In the robot 1 shown in the figure, a rotation member 3 can be provided between the base 2 and the rotating body 3 constituting the first rotation joint axis, and between the first wrist element 7 and the second wrist element 8 constituting the fifth rotation joint axis (not shown). Figure 2 The support surfaces 10 and 20 are used for zero point calibration.

[0070] On the other hand, the zero point calibration support surfaces 10 and 20 between the first arm 4 and the second arm 5 constituting the third rotation joint axis, between the second arm 5 and the first wrist element 7 constituting the fourth rotation joint axis, and between the second wrist element 8 and the third wrist element 9 constituting the sixth rotation joint axis are as shown in FIG. Figure 10 shown.

[0071] Figure 10 The zero point calibration support surfaces 10, 20 are both arranged on the cylindrical surface around the axes C, D, and F, and when arranged at the origin position, the V-grooves 12, 22 are arranged on a straight line or parallel to each other on the same plane.

[0072] For a rotary joint shaft provided with such a zero point calibration support surface 10, 20, as Figure 11 As shown, it is also possible to use Figure 6 The same zero point calibration fixture 50 is used for zero point calibration. That is, it has the following advantages: the same zero point calibration fixture 50 can be used for zero point calibration of multiple rotation joint axes, and there is no need to prepare multiple zero point calibration fixtures in advance.

[0073] In addition, in the present embodiment, zero-point calibration support surfaces 10 and 20 are formed on the outer surfaces of the two components 2, 3, 4, 5, 7, 8, and 9 that constitute each rotary joint axis by machining. However, the components 2, 3, 4, 5, 7, 8, and 9 having the zero-point calibration support surfaces 10 and 20 can also be manufactured as separate components and fixed to the respective components 2, 3, 4, 5, 7, 8, and 9 in a positioned state. Thereby, it has the following advantages: when the zero-point calibration support surfaces 10 and 20 are damaged, it is not necessary to replace the components 2, 3, 4, 5, 7, 8, and 9 that constitute the rotary joint axis, and only the components 2, 3, 4, 5, 7, 8, and 9 having the zero-point calibration support surfaces 10 and 20 need to be replaced.

[0074] In addition, in the present embodiment, while making the V-shaped protrusions 64 and 74 closely contact the V-shaped grooves 12 and 22, the contact surfaces 63 and 73 are made to closely contact the support surfaces 11 and 21. However, in order to position the reference plane 60a and the micrometer 80, the contact surfaces 63 and 73 can also be omitted. By making the contact surfaces 63 and 73 closely contact the support surface 11, it is possible to prevent the reference plane 60a and the micrometer 80 from tipping over to assist in stable positioning.

[0075] In addition, in the present embodiment, V-shaped grooves 12 and 22 are provided on the zero-point calibration support surfaces 10 and 20, and V-shaped protrusions 64 and 74 are provided on the zero-point calibration jig 50. However, as Figure 12 and Figure 13 shown, it can also be set conversely. In addition, it is also possible to provide V-shaped grooves 12 and 22 on one zero-point calibration support surface 10 and 20, and V-shaped protrusions 64 and 74 on the other zero-point calibration support surface 10 and 20.

[0076] In addition, in order to function as a scribing mark, the bottom surfaces 12a and 22a of the V-shaped grooves 12 and 22 provided on the zero-point calibration support surfaces 10 and 20 and the edges 65 and 75 of the V-shaped protrusions 64 and 74 are required. However, the edges 65 and 75 of the V-shaped protrusions 64 and 74 or the linear bottom surfaces 12a and 22a of the V-shaped grooves 12 and 22 in the zero-point calibration jig 50 are not necessary.

[0077] For example, as Figure 14 shown, as long as the concave portion 30 can accommodate the V-shaped protrusions 64 and 74 and has two inclined inner surfaces 32 intersecting at a linear virtual bottom surface 31 extending in a direction orthogonal to the moving direction.

[0078] In addition, as Figure 15 shown, as long as the convex portion 40 has two inclined outer surfaces 42 intersecting at a linear virtual edge 41 extending in a direction orthogonal to the moving direction.

[0079] In addition, in the present embodiment, an example is given of applying to a robot 1 having six rotational joint axes. However, it can be applied not only to rotational joint axes but also to a robot having only linear joint axes or a robot in which rotational joint axes and linear joint axes coexist.

[0080] Explanation of reference numerals:

[0081] 1: Robot

[0082] 2: Base (component)

[0083] 3: Rotating body (component)

[0084] 4: First arm (component)

[0085] 5: Second arm (component)

[0086] 7: First wrist element (component)

[0087] 8: Second wrist element (component)

[0088] 9: Third wrist element (component)

[0089] 12, 22: V-groove (recess)

[0090] 12a, 22a, 31: Bottom of groove

[0091] 13, 23, 32: Inclined inner surface

[0092] 30: Recess

[0093] 40: Protrusion

[0094] 50: Zero calibration jig

[0095] 60: First jig

[0096] 60a: Reference plane (datum plane)

[0097] 70: Second jig

[0098] 64, 74: V-shaped protrusion (protrusion)

[0099] 65, 75, 41: Edge

[0100] 66, 42: Inclined outer surface

Claims

1. A zero-point calibration fixture, characterized in that, it includes: A first fixture having a convex portion or a concave portion. The convex portion has a shape that can simultaneously adhere to two inclined inner surfaces of a V-groove of one of the two components that form a joint axis of the robot and are supported to be relatively movable. The concave portion has a shape that can simultaneously adhere to two inclined outer surfaces of a V-projection of one of the components. The robot is provided with the V-groove or the V-projection on each of the two components. The V-groove has two inclined inner surfaces that intersect at a straight bottom of the groove extending in a direction orthogonal to the moving direction. The V-projection has two inclined outer surfaces that intersect at a straight edge extending in a direction orthogonal to the moving direction. When the two components of the joint axis are arranged at a predetermined operating position, the V-groove or the V-projection is arranged at a position where the bottoms of the grooves, the edges, or the bottom of the groove and the edge are aligned. In a state where the convex portion is in contact with the V-groove or the concave portion is in contact with the V-projection, the first fixture is positioned in the moving direction with respect to one of the components; and A second fixture having a convex portion or a concave portion. The convex portion has a shape that can simultaneously adhere to two inclined inner surfaces of the V-groove of the other component of the robot. The concave portion has a shape that can simultaneously adhere to two inclined outer surfaces of the V-projection of the other component. In a state where the convex portion is in contact with the V-groove or the concave portion is in contact with the V-projection, the second fixture is positioned in the moving direction with respect to the other component, One of the first fixture or the second fixture has a reference surface extending in a direction orthogonal to the moving direction in a state of being positioned on the component, and the other of the first fixture or the second fixture has a measuring instrument capable of measuring the distance along the moving direction to the reference surface in a state of being positioned on the component.

2. A zero-point calibration system, characterized in that, it includes: A robot, on each of the two components that form a joint axis and are supported to be relatively movable, the robot is provided with a V-groove or a V-projection. The V-groove has two inclined inner surfaces that intersect at a straight bottom of the groove extending in a direction orthogonal to the moving direction. The V-projection has two inclined outer surfaces that intersect at a straight edge extending in a direction orthogonal to the moving direction. When the two components of the joint axis are arranged at a predetermined operating position, the V-groove or the V-projection is arranged at a position where the bottoms of the grooves, the edges, or the bottom of the groove and the edge are aligned; and The zero-point calibration fixture according to claim 1.

3. A zero-point calibration method for a joint axis of a robot, characterized in that, The robot is provided with V-grooves or V-protrusions on two components that form a joint axis and are supported so as to be relatively movable. The V-groove has two inclined inner surfaces intersecting at a linear groove bottom extending in a direction orthogonal to the moving direction, and the V-protrusion has two inclined outer surfaces intersecting at a linear edge extending in a direction orthogonal to the moving direction. When the two components of the joint axis are arranged at a predetermined operating position, the V-groove or the V-protrusion is arranged at a position where the groove bottoms, the edges, or the groove bottom and the edge coincide with each other. The zero-point calibration method uses the zero-point calibration jig described in claim 1, and the zero-point calibration method includes: For the joint axis in a state where zero-point calibration has been performed, the first jig is arranged at one of the components in a positioning state, and the second jig is arranged at the other component in a positioning state, and a first distance when the two components are arranged at a first operating position is measured using the measuring instrument; Storing the measured first distance; For the joint axis in a state where zero-point calibration has been lost, the first jig is arranged at one of the components in a positioning state, and the second jig is arranged at the other component in a positioning state, and a second distance when the two components are arranged at a second operating position is measured using the measuring instrument; and Actuating the joint axis until the difference between the measured second distance and the first distance becomes equal to or less than a predetermined threshold value.

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