Calibration device for a robot

Abstract

A calibration device (1) of a robot which has a linear motion shaft (101) that moves a slide (104) relative to a base (103) along a straight line, and a front end shaft (102) that is supported to the slide (104) of the linear motion shaft (101) so as to be able to rotate around a rotation axis, the calibration device (1) of the robot has a first correction jig (2) that is fixed to the front end shaft (102), and a second correction jig (3) that is fixed to the base (103), the first correction jig (2) has a first correction surface (4) that is constituted by a plane that includes the rotation axis or a plane that is parallel to the plane, and a second correction surface (5) that does not change even if only the first correction jig (2) rotates around the rotation axis, and the second correction jig (3) detects a position of the first correction surface (4) when the first correction jig (2) rotates around the rotation axis, and a position of the second correction surface (5) when the first correction jig (2) moves along the straight line.

Description

Technical Field

[0001] This invention relates to a calibration device for robots. Background Technology

[0002] A calibration device for a vertical six-axis articulated robot is known (for example, see Patent Document 1).

[0003] The calibration device comprises: a fixture having three mutually orthogonal planes; and a detection unit that detects the orientation formed between the three planes of the fixture and a reference plane in an orthogonal spatial coordinate system set on the robot's fixed base. According to this calibration device, all axes of a vertical six-axis articulated robot can be calibrated simultaneously.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 4-46714 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The calibration device in Patent Document 1 cannot calibrate the axes of robots with fewer than six axes. Therefore, there is a need for a calibration device capable of calibrating the axes of robots with fewer than six axes.

[0009] Solution for solving the problem

[0010] One aspect of the present invention is a calibration device for a robot, the robot comprising: a linear axis for moving a slider relative to a base along a straight line; and a front end axis for supporting the slider on the linear axis in a manner rotatable about a rotation axis. The calibration device for the robot comprises: a first calibration fixture fixed to the front end axis; and a second calibration fixture fixed to the base. The first calibration fixture comprises: a first calibration surface formed by a plane including the rotation axis or a plane parallel to the plane; and a second calibration surface that remains unchanged even when only the first calibration fixture rotates about the rotation axis. The second calibration fixture detects the position of the first calibration surface when the first calibration fixture rotates about the rotation axis and the position of the second calibration surface when the first calibration fixture moves along the straight line. Attached Figure Description

[0011] Figure 1 This is a perspective view of a robot calibration device according to one embodiment of the present invention.

[0012] Figure 2 It means to Figure 1 The calibration device is installed in the three-dimensional view of the robot's state.

[0013] Figure 3 It means to Figure 1 A three-dimensional view of the calibration device configured in the robot's calibration position.

[0014] Figure 4 It means to Figure 1 The calibration device is installed in the side view of the robot's state.

[0015] Figure 5 This indicates that it is installed. Figure 1 A side view of the state in which the slider of the calibration device of the robot is working to bring the first dial indicator into contact with the second calibration surface.

[0016] Figure 6 It means from Figure 5 The state of the dial indicator causes the first dial indicator to move to the first calibration plane, thus correcting the state of the linear shaft in the side view.

[0017] Figure 7 It means from Figure 6 The state of the first correction fixture is such that it rotates around the axis of rotation, thereby correcting the state of the front end shaft. (Side view)

[0018] Figure 8 It means Figure 1 A perspective view of a modified example of the calibration device.

[0019] Figure 9 It means Figure 1 A perspective view of another variation of the calibration device. Detailed Implementation

[0020] Hereinafter, a robot calibration device 1 according to one embodiment of the present invention will be described with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the robot 100 using the calibration device 1 of this embodiment is, for example, a two-axis robot having a linear axis 101 and a front axis 102.

[0022] like Figure 4 As shown, the robot 100 is used as a tool, for example, by fixing a linear axis 101 to the wrist proximal face 110 of a six-axis articulated robot. In the description of this embodiment, the normal direction of the wrist proximal face 110 of the six-axis articulated robot is defined as the Z-axis, the direction orthogonal to the Z-axis is defined as the X-axis, and the direction orthogonal to both the X-axis and the Z-axis is defined as the Y-axis. Figure 1 In the image, the position indicated by the shading line is the mounting position for mounting onto the wrist end face 110 of the six-axis multi-joint robot.

[0023] The linear axis 101 includes: a base 103, which is fixed to the wrist end face 110 of a six-axis articulated robot; and a slider 104, which is supported on the base 103 in a manner that allows it to move along the X (a straight line) direction. A linear mechanism for driving the slider 104 is built into the base 103 (not shown).

[0024] The front shaft 102, for example, includes a front movable part 105, which is supported on the slider 104 in a manner that allows it to rotate around the rotation axis A. A rotation mechanism (not shown) that drives the front movable part 105 is built into the slider 104. The rotation axis A extends along the Y-axis direction. That is, the rotation axis A extends in a direction along a plane orthogonal to the X-axis, which is the direction of movement of the slider 104.

[0025] like Figure 1 as well as Figure 2 As shown, the calibration device 1 of this embodiment includes: a first calibration clamp 2, which is fixed to the front movable part 105; and a second calibration clamp 3, which is fixed to the base 103.

[0026] like Figure 1 As shown, the first calibration fixture 2 includes: a first calibration surface 4, which is composed of a plane parallel to the rotation axis A; and a second calibration surface 5, which is composed of a cylindrical surface extending approximately half a circumference around the rotation axis A.

[0027] The first correction surface 4 extends along the tangent direction of the second correction surface 5 and is smoothly connected to the second correction surface 5.

[0028] Thus, by operating the movable part 105 at the front end, the first correction fixture 2 is rotated around the rotation axis A. As a result, with the first correction surface 4 positioned in a position extending along the X-axis direction, the second correction surface 5 also functions as an inclined surface adjacent to the end of the first correction surface 4 in the X-axis direction.

[0029] Since the second correction surface 5 is composed of a cylindrical surface around the rotation axis A, it becomes a surface that does not change even when the first correction fixture 2 is rotated around the rotation axis A.

[0030] like Figure 1 as well as Figure 2 As shown, the second calibration fixture 3 includes: a bracket 6, which is detachably fixed to the mounting portion of the base 103 using, for example, screws (not shown); and two dial indicators (first detector and second detector) 7 and 8 fixed to the bracket 6. The bracket 6 is fixed in a state of high-precision positioning on the base 103. The two dial indicators 7 and 8 are fixed to the bracket 6 in a state of high-precision positioning at the front end positions of the plungers 9 and 10, respectively.

[0031] like Figure 4As shown, the second dial indicator 8 is fixed at a position where the plunger 10 appears and disappears along the X-axis in the XY plane including the axis of rotation A. More specifically, when the linear shaft 101 is operated to position the slider 104 at a predetermined calibration position, such as the origin position of the linear shaft 101, the second dial indicator 8 is fixed at a position indicating a predetermined value, such as ±0.0.

[0032] The first dial indicator 7 is positioned further away from the origin of the linear axis 101 than the second dial indicator 8. For example... Figure 3 As shown, with the front end shaft 102 operating to align the first calibration surface 4 of the first calibration fixture 2 parallel to the XY plane, the first dial indicator 7 is fixed at a position representing a predetermined value, for example, ±0.0. Figure 3 For clarity, the illustration of bracket 6 has been omitted.

[0033] The calibration device 1 of the robot of this embodiment, configured as described above, will be used to calibrate the linear axis 101 and the front axis 102.

[0034] First, when simultaneously calibrating both the linear shaft 101 and the front end shaft 102, as follows: Figure 5 As shown, only the front end shaft 102 is operated to align the first correction surface 4 approximately parallel to the XY plane. At this moment, strict parallelism is not required. Next, only the linear shaft 101 is operated to move the slider 104 towards... Figure 5 Move in the direction indicated by the middle arrow.

[0035] If the slider 104 is to be brought closer to the calibration position of the linear shaft 101, then firstly, as Figure 5 As shown, the front end of the first dial indicator 7 contacts the second calibration surface 5 of the first calibration fixture 2. Since the second calibration surface 5 is cylindrical, as the slider 104 approaches the calibration position of the linear shaft 101, the plunger 9 of the first dial indicator 7 is pushed in the contraction direction. Because the second calibration surface 5 is smoothly connected to the first calibration surface 4, if the slider 104 is further brought closer to the calibration position of the linear shaft 101, then as... Figure 6 As shown, the front end of the plunger 9 of the first micrometer 7 moves from the second calibration surface 5 to the first calibration surface 4.

[0036] Since the first calibration surface 4 is configured to be approximately parallel to the XY plane, the reading of the second dial indicator 8 will not change significantly even if only the slider 104 moves after the front end of the plunger 9 of the first dial indicator 7 moves onto the first calibration surface 4.

[0037] Furthermore, if the slider 104 is positioned near the correction position of the linear shaft 101, then as... Figure 6As shown, the front end of the second dial indicator 8 contacts the second calibration surface 5. Since the front end of the plunger 10 of the second dial indicator 8 is disposed on the XY plane including the axis of rotation A, the plunger 10 of the second dial indicator 8 is configured to be perpendicular to the second calibration surface 5.

[0038] In this state, the slider 104 is moved to a position where the reading of the second dial indicator 8 is a predetermined value (e.g., ±0.0), thereby calibrating the direct drive shaft 101.

[0039] Then, make the front movable part 105 as follows Figure 7 The center arrow indicates the position where the reading of the first dial indicator 7 becomes a predetermined value (e.g., ±0.0), thereby calibrating the front end shaft 102.

[0040] According to the calibration device 1 of this embodiment, since the second calibration surface 5 is composed of a cylindrical surface surrounding the rotation axis A, the position of the second calibration surface 5 itself does not change even if only the front end shaft 102 is operated to rotate the first calibration fixture 2 around the rotation axis A. Therefore, even when the front end shaft 102 is not calibrated, the front end of the second dial indicator 8 can be brought into contact with the second calibration surface 5 to calibrate the linear shaft 101, and then the first calibration fixture 2 can be rotated to calibrate the front end shaft 102.

[0041] Furthermore, in the above embodiment, the linear shaft 101 is calibrated first, followed by the front end shaft 102, but the reverse is also possible. That is, with the linear shaft 101 in operation to move the slider 104 to near the calibration position of the linear shaft 101, firstly, the first calibration fixture 2 is rotated about the rotation axis A to align the first calibration surface 4 precisely parallel to the XY plane. As a result, the front end shaft 102 is calibrated. Next, the slider 104 is moved to a position where the reading of the second dial indicator 8 reaches a predetermined value (e.g., ±0.0).

[0042] This also corrects both the front end shaft 102 and the linear shaft 101. In this case, since the first correction surface 4 is set parallel to the plane containing the rotation axis A, as long as the front end shaft 102 is corrected, even if only the linear shaft 101 is operated to move the first correction fixture 2 along the X-axis, the position of the first correction surface 4 itself will not change. Therefore, even if the linear shaft 101 is not corrected, only the front end shaft 102 can be corrected, and then the linear shaft 101 can be corrected.

[0043] That is, the calibration device 1 according to this embodiment can not only calibrate the linear shaft 101 and the front end shaft 102 at the same time, but also calibrate only one of them.

[0044] Especially when used as a tool mounted on the wrist end face 110 of a six-axis articulated robot, sometimes only one axis needs to be maintained due to contact with surrounding objects. In this case, it is also possible to calibrate only the axis that needs maintenance.

[0045] In this embodiment, the cylindrical surface constituting the second calibration surface 5 is used to form an inclined surface that guides the first micrometer 7 to the first calibration surface 4. Alternatively, a curved surface that smoothly connects to the two calibration surfaces or an inclined surface composed of planes can be used between the first calibration surface 4 and the second calibration surface 5.

[0046] In this embodiment, the front-end axis 102 is exemplified as a front-end axis 102 that rotates the front-end movable part 105 about a rotation axis A extending in the Y-axis direction. Alternatively, it can also be applied to a robot 100 having a front-end axis 102 that rotates the front-end movable part 105 about a rotation axis extending in the X-axis or Z-axis direction.

[0047] For example, when the axis of rotation A extends along the X-axis, such as Figure 8 As shown, the first calibration surface 4 uses the same plane as the plane described above, which is the same as the plane of the first calibration fixture 2, and the second calibration surface 5 uses the plane of the first calibration fixture 2 that is orthogonal to the X-axis. In this case, the second calibration surface 5 can also be set as a surface that does not change only when the first calibration fixture 2 is rotated around the rotation axis A, and the linear shaft 101 and the front end shaft 102 can be calibrated simultaneously or separately. Reference numeral 11 in the figure indicates the inclined surface that guides the first dial indicator 7 to the first calibration surface 4.

[0048] Furthermore, in this embodiment, the case of a robot 100 having a single linear axis 101 and a single front-end axis 102 is described. Instead, as... Figure 9 As shown, it can also be applied to a robot 100 with two linear axes 111 and 112 and a front axis 102, which enable each slider 113 and 114 to move in mutually orthogonal directions.

[0049] In this case, a bracket 6 (not shown) is fixed in a positioning state on the first linear axis 111 of the wrist end face 110 of the six-axis multi-joint robot, and three dial indicators 7, 8, and 13 are fixed in the positioning state on the bracket 6.

[0050] exist Figure 9 In the example shown, the first calibration fixture 2 includes: a first calibration surface 4 parallel to the plane containing the rotation axis A, a second calibration surface 5 formed by a cylindrical surface surrounding the rotation axis A, and a third calibration surface 12 orthogonal to the rotation axis A.

[0051] Additionally, the first linear shaft 111 includes: a first base 115 fixed to the front end face 110 of the wrist of the robot 100; and a first slider 113 supported on the first base 115 in a manner that enables it to move along a first straight line.

[0052] The second linear shaft 112 includes: a second base 116 fixed to the first slider 113; and a second slider 114 supported on the second base 116 in a manner that allows it to move along a second straight line orthogonal to the first straight line. The front shaft 102 includes a front movable portion 105, which is supported on the second slider 114 in a manner that allows it to rotate about the rotation axis A.

[0053] The three dial indicators 7, 8, and 13 are: the first dial indicator 7 for detecting the position of the first calibration surface 4, the second dial indicator 8 for detecting the position of the second calibration surface 5, and the third dial indicator 13 for detecting the position of the third calibration surface 12. The first calibration fixture 2 includes: an inclined surface 11 that allows the first dial indicator 7 to climb onto the first calibration surface 4 from the side of the third calibration surface 12; and an inclined surface 14 that allows the third dial indicator 13 to climb onto the third calibration surface 12 from the side of the second calibration surface 5. As the inclined surface that allows the first dial indicator 7 to climb onto the first calibration surface 4 from the side of the second calibration surface 5, a cylindrical surface constituting the second calibration surface 5 is used.

[0054] The second correction surface 5 and the third correction surface 12 are each composed of surfaces that will not change even when the first correction fixture 2 is rotated around the rotation axis A when the first correction surface 4 is used to correct the front end shaft 102.

[0055] When using the calibration device 1 to calibrate the robot 100, the first calibration surface 4 and the third calibration surface 12 are positioned at approximately the calibrated position, and the second slider 114 of the second linear shaft 112 is moved along the Y-axis.

[0056] Thus, the first dial indicator 7 climbs up the first calibration surface 4 via the inclination of the second calibration surface 5, and the third dial indicator 13 climbs up the third calibration surface 12 via the inclination surface 14. Then, the plunger 10 of the second dial indicator 8 is pushed by the second calibration surface 5, and the second direct-acting shaft 112 is calibrated at the moment when the reading of the second dial indicator 8 reaches a predetermined value (e.g., ±0.0).

[0057] Next, the first calibration fixture 2 is rotated around the rotation axis A. When the first calibration surface 4 is strictly parallel to the XY plane, the reading of the first dial indicator 7 becomes a predetermined value (e.g., ±0.0), and the front end shaft 102 is calibrated.

[0058] Then, the first slider 113 of the first direct-acting shaft 111 is moved along the X-axis. Then, the plunger 15 of the third dial indicator 13 is pushed by the third correction surface 12, and the first direct-acting shaft 111 is corrected when the reading of the third dial indicator 13 becomes a predetermined value (e.g., ±0.0).

[0059] By using this calibration device 1, the following advantages are available: it is possible to simultaneously or separately calibrate the three axes of a robot 100, which has two linear axes 111 and 112 and a front end axis 102.

[0060] In addition, dial gauges 7, 8, and 13 were used as detection units in this embodiment, but it is not limited to these and any other contact or non-contact detection units can be used.

[0061] In addition, the determination of whether calibration has been performed can be made by the operator using the readings of dial gauges 7, 8, and 13, or by the processor using the output electrical signals from dial gauges 7, 8, and 13.

[0062] Explanation of reference numerals in the attached figures:

[0063] 1: Calibration device

[0064] 2: First calibration fixture

[0065] 3: Second calibration fixture

[0066] 4: First calibration plane

[0067] 5: Second correction surface

[0068] 11: Inclined surface

[0069] 12: Third Correction Plane

[0070] 100: Robot

[0071] 101: Direct-acting shaft

[0072] 102: Front Axis

[0073] 103: Base

[0074] 104: Slider

[0075] 111: First direct-drive shaft

[0076] 112: Second direct-acting shaft

[0077] 113: First slider

[0078] 114: Second slider

[0079] 115: First Pyramid

[0080] 116: Second Plinth

[0081] A: Axis of rotation

Claims

1. A calibration apparatus for a robot, the robot comprising: a linear axis for moving a slider relative to a base along a straight line; and a front end axis supported on the slider of the linear axis in a manner rotatable about a rotation axis, characterized in that, The robot's calibration device includes: A first alignment clamp, which is fixed to the front end shaft; and The second calibration clamp is fixed to the base. The first calibration fixture includes: a first calibration surface, which is formed by a plane including the axis of rotation or a plane parallel to the plane; and a second calibration surface, which is connected to the first calibration surface and remains unchanged even when only the first calibration fixture rotates about the axis of rotation. The second calibration fixture detects the position of the first calibration surface when the first calibration fixture is rotated around the rotation axis, and the position of the second calibration surface when the first calibration fixture is moved along the straight line.

2. The robot calibration device according to claim 1, characterized in that, The second calibration fixture includes a first detector for detecting the position of the first calibration surface. When the first detector detects that the first correction surface is configured in a manner parallel to the straight line, it is determined that the front end shaft has been corrected.

3. The robot calibration device according to claim 1 or 2, characterized in that, The second calibration fixture includes a second detector for detecting the position of the second calibration surface. When the second detector detects that the second correction surface is positioned at a predetermined position, it is determined that the linear shaft has been corrected.

4. The calibration device for a robot according to claim 1 or 2, characterized in that, The axis of rotation is positioned in a plane orthogonal to the straight line. The second correction surface is formed by a cylindrical surface surrounding the axis of rotation.

5. The robot calibration device according to claim 3, characterized in that, The axis of rotation is positioned in a plane orthogonal to the straight line. The second correction surface is formed by a cylindrical surface surrounding the axis of rotation. The second detector detects the second correction surface in a plane that includes the axis of rotation and the straight line.

6. The robot calibration device according to claim 2, characterized in that, The first detector is a plunger-type instrument. With the first correction surface arranged along the straight line direction, an inclined surface connected to the first correction surface is provided at a position adjacent to the first correction surface in the straight line direction.

7. A calibration apparatus for a robot, the robot comprising: a first linear axis for moving a first slider relative to a first base along a first straight line; a second linear axis for moving a second slider relative to a second base fixed to the first slider along a second straight line orthogonal to the first straight line; and a front end shaft supported on the second slider in a manner rotatable about a rotation axis, characterized in that, The robot's calibration device includes: A first alignment clamp, which is fixed to the front end shaft; and The second calibration clamp is fixed to the first base. The first calibration fixture includes: a first calibration surface, which is formed by a plane containing the axis of rotation or a plane parallel to the axis of rotation; and a second calibration surface and a third calibration surface that are orthogonal to each other, wherein the second calibration surface and the third calibration surface remain unchanged even when only the first calibration fixture rotates about the axis of rotation. The second and third correction surfaces are connected to the first correction surface. The second calibration fixture detects the position of the first calibration surface when the first calibration fixture is rotated around the rotation axis, the position of the second calibration surface when the first calibration fixture is moved along the first straight line, and the position of the third calibration surface when the first calibration fixture is moved along the second straight line.

Images