JP5071237B2 - 5-axis origin position calibration method for 6-axis robot, 6-axis robot controller, articulated robot axis origin position calibration method, and articulated robot controller - Google Patents

Description

  In the present invention, one rotation axis is orthogonal to the installation surface of the six-axis robot, two rotation axes are orthogonal to the one rotation axis, two rotation axes, three rotation axes, and five axes. Measured on a plane parallel to the rotation axis, orthogonal to the five rotation axes at the same point as the four rotation axes and the six rotation axes, and including one rotation axis and perpendicular to the two rotation axes. Method for calibrating 5-axis origin position in 6-axis robot configured to have points, control apparatus for 6-axis robot, method for calibrating n-axis origin position in articulated robot, and articulated joint The present invention relates to a control device for a type robot.

For example, the calibration of the origin position of each axis in an articulated robot such as a 6-axis robot is basically performed at the factory before shipment from the factory, and after being shipped from the factory and installed at the installation site, the motor This is done at the installation site when the origin position is changed by exchanging the above. As a method of calibrating the origin position of each axis, a method of attaching a dedicated jig to the hand or installing a large detection instrument (for example, see Patent Documents 1 and 2), a method of adding a sensor for detection (See, for example, Patent Document 3).
JP-A-8-132366 JP-A-6-304893 Japanese Patent Laid-Open No. 2003-220587

  However, there is a risk that it may be difficult to attach the jig to the hand depending on the state of the articulated robot, and to secure a space for installing a large detector. May be difficult. In addition, there is a situation where it is desired to avoid the implementation of a method for adding a sensor for detection because it causes an increase in cost.

  The present invention has been made in view of the above-described circumstances, and the object thereof is not to install a dedicated jig or to install a large detection instrument, and to determine the origin position of the five axes in the six-axis robot. 5-axis origin position calibration method of 6-axis robot capable of being properly calibrated, control apparatus for 6-axis robot, axis origin of articulated robot capable of appropriately calibrating n-axis origin position in articulated robot It is an object to provide a position calibration method and a control device for an articulated robot.

  According to the first and third aspects of the invention, the one rotation axis is orthogonal to the installation surface of the six-axis robot, the two rotation axes are orthogonal to the one rotation axis, and the two rotation axes are The three rotation axes and the five rotation axes are parallel, the five rotation axes are orthogonal to the four rotation axes and the six rotation axes at the same point, and include the one rotation axis. In a 6-axis robot configured such that a measurement point exists on a plane orthogonal to the rotation axis, an angle formed by the 4 rotation axes and the 6 rotation axes is θa5, and the 6-axis robot is measured. The first step of holding the rotation axis, the second step of rotating the four axes by 180 degrees, the third step of rotating the five axes by 2 times θa5, the coordinates of the measurement point in the measurement posture, and the third A line segment connecting the coordinates of the measurement point after the process is derived is derived, passes through the center coordinates of the derived line segment, and is orthogonal to the line segment. A fifth step is performed in which the five axes are rotated so that the coordinates of the measurement points overlap on the straight line, and the rotation angle when the coordinates of the measurement points overlap on the straight line is derived as an error angle, and the error angle is set to θa5. A fifth step of adding and calibrating the origin positions of the five axes is performed.

  The coordinates of the measurement point before moving each axis and the coordinates of the measurement point after moving each axis match if the origin positions of the five axes are not deviated. If they are off, they will not match. Therefore, a line segment connecting the coordinates of the measurement point before moving each axis and the coordinates of the measurement point after moving each axis is derived, passing through the center coordinates of the derived line segment, and the line By rotating the five axes so that the coordinates of the measurement points overlap on a straight line orthogonal to the minute, and deriving the rotation angle when the coordinates of the measurement points overlap on the straight line as the error angle, the origin position of the five axes is determined. Can be calibrated appropriately. At this time, it is sufficient if there is a device capable of detecting the coordinates of the measurement point, so there is no need to attach a dedicated jig or install a large detection tool, and the 5-axis origin position in the 6-axis robot is appropriately set. Can be calibrated.

  In other words, there is no major error in the axis origin position even if the motor is replaced at the installation site before the factory shipment. Basically, the origin of the current axis is not changed when the robot is assembled. The position is close to the ideal position (as it should be), and the minute error in the origin position in this state is due to the shape difference in the production lot and the shape difference in the individual. . Therefore, if the origin position is calibrated in order to eliminate such a slight error in the origin position, if there is an apparatus capable of detecting the coordinates of the measurement point by performing the method of the present invention, the origin position is set. Can be calibrated appropriately.

  According to the second and fourth aspects of the invention, the one rotation axis is orthogonal to the installation surface of the six-axis robot, the two rotation axes are orthogonal to the one rotation axis, and the two rotation axes are The three rotation axes and the five rotation axes are parallel, the five rotation axes are orthogonal to the four rotation axes and the six rotation axes at the same point, and include the one rotation axis. In a 6-axis robot configured such that a measurement point exists on a plane orthogonal to the rotation axis, an angle formed by the 4 rotation axes and the 6 rotation axes is θa5, and the 6-axis robot is measured. The first step of holding the rotation axis, the second step of rotating the four axes by 180 degrees, the third step of rotating the five axes by 2 times θa5, the coordinates of the measurement point in the measurement posture, and the third The distance between the coordinates of the measurement point after performing the process is L5, the distance between the coordinates of the 5-axis rotation center and the coordinates of the measurement point is L5, When the difference angle is Δθ5, the fourth step of deriving the error angle according to the calculation formula of Δθ5 = arcsin ((l5 / 2) / L5) is performed, and the error angle is added to θa5 to obtain the origin of the five axes. A fifth step of calibrating the position is performed.

  In this case, the distance between the coordinate of the measurement point in the measurement posture and the coordinate of the measurement point after performing the third step is set to 15 between the coordinates of the rotation center of 5 and the coordinate of the measurement point. When the distance is L5 and the error angle is Δθ5, the error angle can be derived using the calculation formula of Δθ5 = arcsin ((l5 / 2) / L5), and the operator can move the articulated robot. Since there is no need to actually move, the error angle can be easily derived.

  According to the invention described in claims 5 and 7, it has an n (n is a natural number of 2 or more) axis, a p (p is a natural number smaller than n) axis, and a q (q is a natural number larger than n) axis. The p-axis rotation axis, the n-axis rotation axis, and the q-axis rotation axis intersect at one point, and the n-axis rotation axis is orthogonal to the p-axis rotation axis and the q-axis rotation axis. In the articulated robot, the angle formed by the rotation axis of the p-axis and the rotation axis of the q-axis is θan, the first step of holding the articulated robot in the measurement posture is performed, and the p-axis is rotated 180 degrees. 2 steps are performed, a third step of rotating the n-axis by 2 times θan is performed, and a line segment connecting the coordinates of the measurement points in the measurement posture and the coordinates of the measurement points after performing the third step is obtained. N so that the coordinates of the measurement points overlap on a straight line passing through the center coordinates of the derived line segment and orthogonal to the line segment. A fourth step of deriving the rotation angle when the coordinate of the measurement point overlaps the straight line as an error angle is performed, and the origin angle of the n-axis is calibrated by adding the error angle to θan. 5 steps are performed.

  As a result, even in an articulated robot other than the 6-axis robot, if each axis is in the above-described relationship, the origin position of the n-axis is appropriately calibrated by performing the above-described first to fifth steps. it can.

  According to the invention described in claims 6 and 8, it has an n (n is a natural number of 2 or more) axis, a p (p is a natural number smaller than n) axis, and a q (q is a natural number larger than n) axis. The p-axis rotation axis, the n-axis rotation axis, and the q-axis rotation axis intersect at one point, and the n-axis rotation axis is orthogonal to the p-axis rotation axis and the q-axis rotation axis. In the articulated robot, the angle formed by the rotation axis of the p-axis and the rotation axis of the q-axis is θan, the first step of holding the articulated robot in the measurement posture is performed, and the p-axis is rotated 180 degrees. The second step is performed, the third step of rotating the n-axis by 2 times θan is performed, and the distance between the measurement point coordinates in the measurement posture and the measurement point coordinates after the third step is determined. In, when the distance between the coordinates of the rotation center of the n-axis and the coordinates of the measurement point is Ln and the error angle is Δθn, Δθn = a Perform a fourth step of deriving the error angle in accordance with calculation formula csin ((ln / 2) / Ln), it performs a fifth step of calibrating the position of the origin of n axis by adding the error angle Shitaan.

  Also in this case, the distance between the coordinates of the measurement point before moving each axis and the coordinates of the measurement point after moving each axis is ln, the coordinates of the rotation center of the n axis and the coordinates of the measurement point And Ln and the error angle is Δθn, the error angle can be derived using the calculation formula of Δθn = arcsin ((ln / 2) / Ln). Since there is no need to actually move the articulated robot, the error angle can be easily derived.

  Hereinafter, as an embodiment of the present invention, a method for calibrating a 5-axis origin position in a 6-axis vertical articulated robot will be described with reference to the drawings. As shown in FIG. 1, the robot device 1 includes a vertical articulated robot (hereinafter referred to as a robot) 2, a control device 3 that controls the operation of the robot 2, and a teaching pendant 4 that is connected to the control device 3. And is configured.

  The robot 2 includes a base 5, a shoulder portion 6 supported by the base 5 so as to be turnable in the horizontal direction, a lower arm 7 supported by the shoulder portion 6 so as to be turnable in the vertical direction, and a lower arm 7 A first upper arm 8 that is supported so as to be pivotable in a direction, a second upper arm 9 that is supported by a tip portion of the first upper arm 8 in a twistable manner, and a second upper arm 9. The wrist 10 is supported by being rotatable in the vertical direction, and the flange 11 is supported by the wrist 10 so as to be rotatable (twisting).

  The shoulder portion 6, the lower arm 7, the first upper arm 8, the second upper arm 9, the wrist 10, and the flange 11 including the base 5 described above function as links in the robot 2, and each link excluding the base 5 Is rotatably connected to the lower link by a rotary joint. A flange (not shown) for gripping a workpiece can be attached to the flange 11 which is the most advanced link. In addition, the rotary joint that connects the links is provided with a reduction gear that reduces the rotation of the motor fixed to the previous link and transmits it to the next link.

  In the present embodiment, the joint axis of the rotary joint that connects between the base 5 that is the first link and the shoulder portion 6 that is the second link is one axis, and the shoulder portion 6 that is the second link, Two joint axes of the rotary joint connecting between the lower link 7 as the third link and between the lower arm 7 as the third link and the first upper arm 8 as the fourth link Three joint axes of the rotary joint to be connected, and four joint axes of the rotary joint connecting the first upper arm 8 being the fourth link and the second upper arm 9 being the fifth link. In addition, the five joint axes of the rotary joint connecting the second upper arm 9 as the fifth link and the wrist 10 as the sixth link, and the wrist 10 and the seventh link as the sixth link The joint axes of the rotary joint that connects with the flange 11 are shown as six axes.

  That is, as shown in FIG. 3, the robot 2 is a PUMA type robot having 6-axis vertical articulated joints, and the 1-axis rotation axis is perpendicular to the installation surface of the 6-axis robot, and the 2-axis rotation axis is Orthogonal to one rotation axis, two rotation axes, three rotation axes, and five rotation axes are parallel, and the five rotation axes are the same as the four rotation axes and the six rotation axes. A measurement point exists on a plane that is orthogonal at one point and includes one rotation axis and is orthogonal to the two rotation axes. That is, in the present invention, n is “5”, p is “4”, and q is “6”.

  As illustrated in FIG. 2, the control device 3 that controls the operation of the robot 2 includes a CPU 12, a drive circuit 13, and a position detection circuit 14. The CPU 12 is connected with a ROM 15 for storing a robot language for creating a system program and an operation program for the entire robot 2 and a RAM 16 for storing an operation program for the robot 2 and used for teaching work. Teaching pendant 4 is connected. As shown in FIG. 1, the teaching pendant 4 includes various operation units 4a and a display 4b.

  The position detection circuit 14 is for detecting the positions of the shoulder portion 6, the arms 7 to 9, the wrist 10 and the flange 11. The position detection circuit 14 is provided for each axis of the shoulder portion 6, the arms 7 to 9, the wrist 10 and the flange 11. A rotary encoder 18 provided in a motor 17 that is a drive source is connected. Based on the detection signal input from the rotary encoder 18, the position detection circuit 14 rotates the shoulder portion 6 with respect to the base 5, the lower arm 7 with respect to the shoulder 6, and the first upper arm 8 with respect to the lower arm 7. The angle, the rotation angle of the second upper arm 9 relative to the first upper arm 8, the rotation angle of the wrist 10 relative to the second upper arm 9, and the rotation angle of the flange 11 relative to the wrist 10 are detected, and the detected position detection information Is output to the CPU 12. The CPU 12 controls the operation of the shoulder unit 6, the arms 7 to 9, the wrist 10 and the flange 11 based on the operation program using the position detection information input from the position detection circuit 14 as a feedback signal. To do.

  As shown in FIG. 1, three-dimensional coordinates are defined for each link. Among these, the coordinate system of the base 5 installed on the floor surface is a reference coordinate of the robot 2 as a stationary coordinate system, and the horizontal coordinate axes Xb and Yb are set with the center of the lower end of the base 5 as the origin. And one coordinate axis Zb in the vertical direction is defined. In the coordinate system of the other links, the position and orientation on the reference coordinates change due to the rotation of each rotary joint, and the CPU 12 receives the shoulder 6, the arms 7 to 9, the wrist 10, and the flange input from the position detection circuit 14. 11 based on the position detection information of each rotary joint and the length information of each joint stored in advance, the position and orientation of the coordinates of each joint are converted to the position and orientation on the reference coordinates by the coordinate conversion calculation function. Convert to and recognize.

  In the robot 2 described above, the calibration of the origin position of each axis is basically performed at the factory before shipment from the factory, and after being shipped from the factory and installed at the installation site, such as a motor. This is done at the installation site when the home position is changed by replacement. Hereinafter, a procedure for calibrating the origin positions of the five axes will be described with reference to FIGS.

  The CPU 12 stores and holds a control program for calibrating the origin positions of the five axes, and executes the control program to calibrate the origin positions of the five axes. Here, FIG. 4 shows processing performed by the CPU 12, and FIG. 5 shows a state transition diagram in the case where the origin positions of the five axes are in the normal position (not shifted from the normal position). In FIG. 5, one to three axes are omitted.

  First, as shown in FIG. 5A, the CPU 12 performs a first step of holding the robot 2 in the measurement posture so that the four rotation axes and the six rotation axes form an angle θa5. (Step S1). Next, as shown in FIG. 5B, the CPU 12 performs a second step of operating the 4-axis motor 17 to rotate the 4-axis by 180 degrees (step S2). Then, as shown in FIG. 5C, the CPU 12 performs a third step of operating the 5-axis motor 17 to rotate the 5-axis twice as much as θa5 (step S3).

  Here, in the robot 2, if the origin position of the five axes is not deviated from the normal position, as shown in FIG. 5, in the second process, the six axes are rotated by four degrees by rotating the four axes by 180 degrees. The extension line of the axis is moved about the center of symmetry, and in the third step, the 5 axis is rotated twice as much as θa5 to move the 6 axis to the extension line of the 4 axis rotation axis as the center of the movement amount. Therefore, the coordinates of the measurement point after performing the third step returns to the coordinates in the measurement posture, the coordinates of the measurement point before moving each axis, and the coordinates of the measurement point after moving each axis Will match.

  However, if the origin position of the five axes is deviated from the normal position, the phenomenon described below occurs. FIG. 6 shows a state transition diagram in the case where the origin position of the five axes is not at the regular position (deviation from the regular position). In FIG. 6, one axis or three axes are omitted. That is, as shown in FIG. 6, in the case where the error angle Δθ5 is generated as the deviation of the five-axis origin position while the robot 2 is held in the measurement posture, similarly to the procedure described in FIG. When the 4th motor 17 is operated and the 4th axis is rotated 180 degrees, the 5th axis motor 17 is operated and the 5th axis is rotated 2 times θa5. The coordinates of the measurement points after performing the third step due to the influence of Δθ5 do not return to the coordinates in the measurement posture, and the coordinates of the measurement points and the axes before moving each axis are moved. The coordinates of the later measurement points will not match.

When the origin positions of the five axes are deviated from the normal positions in this way, as shown in FIG. 7, the coordinates of the measurement points before moving each axis and the measurement points after moving each axis are moved. If the distance between the coordinates is l5, and the distance between the coordinates of the five-axis rotation center and the coordinates of the measurement point is L5,
sin (Δθ5) = ((l5 / 2) / L5)
Is established,
Δθ5 = arcsin ((l5 / 2) / L5)
The relationship is established.

  Thereby, the CPU 12 performs the fourth step of deriving the error angle Δθ5 in accordance with the calculation formula of Δθ5 = arcsin ((l5 / 2) / L5). Then, the CPU 12 performs a fifth step of calibrating the origin positions of the five axes by adding the error angle Δθ5 to θa5 (step S5). By performing the above processing, the origin positions of the five axes can be calibrated.

  In the above-described configuration, the case where the error angle Δθ5 is derived according to the calculation formula to calibrate the origin positions of the five axes has been described, but the error angle may be derived by actually moving the robot 2. That is, a line segment connecting the coordinates before moving each axis and the coordinates after moving each axis is derived, and measured on a straight line passing through the center coordinates of the derived line segment and orthogonal to the line segment. The five axes may be rotated so that the coordinates of the points overlap, and the rotation angle when the coordinates of the measurement points overlap on the straight line may be derived as an error angle.

  Further, the method of calibrating the origin position of the axis according to the above-described procedure is generalized. The n (n is a natural number of 2 or more) axis, the p (p is a natural number smaller than n) axis, and the q (q is larger than n). A natural number) axis, the p-axis rotation axis, the n-axis rotation axis, and the q-axis rotation axis intersect at one point, and the n-axis rotation axis is the p-axis rotation axis and the q-axis rotation axis. Any robot that satisfies the orthogonal condition can be applied to a method of calibrating the n-axis origin position. That is, as shown in FIG. 8, for a robot having, for example, a seven-axis vertical articulated joint, the one-axis rotation axis, the two-axis rotation axis, and the three-axis rotation axis intersect at one point, and two-axis rotation It can be applied to a method of calibrating the origin positions of two axes as long as the conditions satisfying the condition that the axes are orthogonal to the one rotation axis and the three rotation axes can be applied. And the four rotation axes and the five rotation axes meet at one point and the four rotation axes are orthogonal to the three rotation axes and the five rotation axes. For example, the method can be applied to a method of calibrating the origin positions of the four axes, the five rotation axes, the six rotation axes, and the seven rotation axes intersect at one point, and the six rotation axes are five axes. If the conditions configured to be orthogonal to the 7 and 7 rotation axes are satisfied, the origin position of 6 axes should be calibrated It can be applied to.

  As described above, according to this embodiment, the four rotation axes, the five rotation axes, and the six rotation axes intersect at one point, and the five rotation axes are the four rotation axes and the six rotation axes. In the control device 3 of the robot 2 orthogonal to the rotation axis of the axis, each axis is moved so that the coordinates of the measurement point return from the state where the robot 2 is held in the measurement posture, and the origin positions of the five axes are shifted. Using the characteristic that the coordinates of the measurement point before moving each axis and the coordinates of the measurement point after moving each axis do not match, the coordinates of the measurement point before moving each axis and each Since the error angle is derived by comparing with the coordinates of the measurement point after the axis is moved and the origin position of the five axes is calibrated, any device capable of detecting the coordinates of the measurement point is sufficient. There is no need to install a dedicated jig or install a large detector. Rukoto can.

The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
The p-axis, n-axis, and q-axis do not need to be continuous axes, and another axis may be interposed between the p-axis and the n-axis as long as the above conditions are satisfied. Another axis may be interposed between the axis and the q axis.

1 is a perspective view of a robot apparatus according to an embodiment of the present invention. Functional block diagram Schematic diagram showing the relationship of each axis flowchart State transition diagram Figure equivalent to FIG. The figure which shows the relationship between the coordinate of the measurement point before moving each axis, and the coordinate of the measurement point after moving each axis 3 equivalent figure

Explanation of symbols

  In the drawing, 2 is a robot (6-axis robot, articulated robot), and 3 is a control device.

Claims (8)

One axis of rotation is orthogonal to the installation surface of the six-axis robot, two axes of rotation are orthogonal to one axis of rotation, two axes of rotation, three axes of rotation, and five axes of rotation are The measurement points exist on a plane that is parallel, has five rotation axes orthogonal to the four rotation axes and the six rotation axes at the same point, and includes one rotation axis and perpendicular to the two rotation axes. A method for calibrating the origin positions of the five axes in a six-axis robot configured as described above,
A first step of holding the 6-axis robot in a measurement posture with θa5 being an angle formed by the 4-axis rotation axis and the 6-axis rotation axis;
A second step of rotating the four axes 180 degrees;
A third step of rotating the five axes twice as much as θa5;
A line segment connecting the coordinates of the measurement point in the measurement posture and the coordinates of the measurement point after performing the third step is derived, passes through the center coordinates of the derived line segment, and is orthogonal to the line segment. A fourth step of rotating the five axes so that the coordinates of the measurement points overlap on a straight line, and deriving the rotation angle when the coordinates of the measurement points overlap on the straight line as an error angle;
a fifth step of calibrating the origin positions of the five axes by adding the error angle to θa5;
5 axis origin position calibration method of 6 axis robot characterized by performing sequentially. One axis of rotation is orthogonal to the installation surface of the six-axis robot, two axes of rotation are orthogonal to one axis of rotation, two axes of rotation, three axes of rotation, and five axes of rotation are The measurement points exist on a plane that is parallel, has five rotation axes orthogonal to the four rotation axes and the six rotation axes at the same point, and includes one rotation axis and perpendicular to the two rotation axes. A method for calibrating the origin positions of the five axes in a six-axis robot configured as described above,
A first step of holding the 6-axis robot in a measurement posture with θa5 being an angle formed by the 4-axis rotation axis and the 6-axis rotation axis;
A second step of rotating the four axes 180 degrees;
A third step of rotating the five axes twice as much as θa5;
The distance between the coordinate of the measurement point in the measurement posture and the coordinate of the measurement point after performing the third step is l5, and the distance between the coordinate of the rotation center of 5 axes and the coordinate of the measurement point is L5, when the error angle is Δθ5,
Δθ5 = arcsin ((l5 / 2) / L5)
A fourth step of deriving the error angle according to the formula:
a fifth step of calibrating the origin positions of the five axes by adding the error angle to θa5;
5 axis origin position calibration method of 6 axis robot characterized by performing sequentially. One axis of rotation is orthogonal to the installation surface of the six-axis robot, two axes of rotation are orthogonal to one axis of rotation, two axes of rotation, three axes of rotation, and five axes of rotation are The measurement points exist on a plane that is parallel, has five rotation axes orthogonal to the four rotation axes and the six rotation axes at the same point, and includes one rotation axis and perpendicular to the two rotation axes. In the control apparatus for a six-axis robot configured as described above,
A first step of holding the 6-axis robot in a measurement posture with θa5 being an angle formed by the 4-axis rotation axis and the 6-axis rotation axis;
A second step of rotating the four axes 180 degrees;
A third step of rotating the five axes twice as much as θa5;
A line segment connecting the coordinates of the measurement point in the measurement posture and the coordinates of the measurement point after performing the third step is derived, passes through the center coordinates of the derived line segment, and is orthogonal to the line segment. A fourth step of rotating the five axes so that the coordinates of the measurement points overlap on a straight line, and deriving the rotation angle when the coordinates of the measurement points overlap on the straight line as an error angle;
a fifth step of calibrating the origin positions of the five axes by adding the error angle to θa5;
A control apparatus for a six-axis robot, characterized in that One axis of rotation is orthogonal to the installation surface of the six-axis robot, two axes of rotation are orthogonal to one axis of rotation, two axes of rotation, three axes of rotation, and five axes of rotation are The measurement points exist on a plane that is parallel, has five rotation axes orthogonal to the four rotation axes and the six rotation axes at the same point, and includes one rotation axis and perpendicular to the two rotation axes. In the control apparatus for a six-axis robot configured as described above,
A first step of setting the angle formed by the four rotation axes and the six rotation axes to θan and holding the six-axis robot in a measurement posture;
A second step of rotating the four axes 180 degrees;
A third step of rotating the five axes twice as much as θa5;
The distance between the coordinate of the measurement point in the measurement posture and the coordinate of the measurement point after performing the third step is l5, and the distance between the coordinate of the rotation center of 5 axes and the coordinate of the measurement point is L5, when the error angle is Δθ5,
Δθ5 = arcsin ((l5 / 2) / L5)
A fourth step of deriving the error angle according to the formula:
a fifth step of calibrating the origin positions of the five axes by adding the error angle to θa5;
A control apparatus for a six-axis robot, characterized in that It has an n (n is a natural number greater than or equal to 2) axis, a p (p is a natural number less than n) axis, and a q (q is a natural number greater than n) axis, and the rotation axis of n axis is the rotation axis of p axis and q A method of calibrating the origin position of the n-axis in an articulated robot configured to be orthogonal to the rotation axis of the axis at the same point,
a first step of setting the angle formed by the rotation axis of the p-axis and the rotation axis of the q-axis to θan, and holding the articulated robot in a measurement posture;
a second step of rotating the p-axis 180 degrees;
a third step of rotating the n-axis by twice θan;
A line segment connecting the coordinates of the measurement point in the measurement posture and the coordinates of the measurement point after performing the third step is derived, passes through the center coordinates of the derived line segment, and is orthogonal to the line segment. A fourth step of rotating the n-axis so that the coordinates of the measurement point overlap the straight line, and deriving the rotation angle when the coordinate of the measurement point overlaps the straight line as an error angle;
a fifth step of calibrating the n-axis origin position by adding the error angle to θan;
A method for calibrating the axis origin position of an articulated robot, characterized in that It has an n (n is a natural number greater than or equal to 2) axis, a p (p is a natural number less than n) axis, and a q (q is a natural number greater than n) axis, and the rotation axis of n axis is the rotation axis of p axis and q A method of calibrating the origin position of the n-axis in an articulated robot configured to be orthogonal to the rotation axis of the axis at the same point,
a first step of setting the angle formed by the rotation axis of the p-axis and the rotation axis of the q-axis to θan, and holding the articulated robot in a measurement posture;
a second step of rotating the p-axis 180 degrees;
a third step of rotating the n-axis by twice θan;
The distance between the coordinate of the measurement point in the measurement posture and the coordinate of the measurement point after performing the third step is ln, and the distance between the coordinate of the rotation center of the n-axis and the coordinate of the measurement point is Ln, when the error angle is Δθn,
Δθn = arcsin ((ln / 2) / Ln)
A fourth step of deriving the error angle according to the formula:
a fifth step of calibrating the n-axis origin position by adding the error angle to θan;
A method for calibrating the axis origin position of an articulated robot, characterized in that It has an n (n is a natural number greater than or equal to 2) axis, a p (p is a natural number less than n) axis, and a q (q is a natural number greater than n) axis, and the rotation axis of n axis is the rotation axis of p axis and q In the control device for an articulated robot configured to be orthogonal to the rotation axis of the shaft at the same point,
a first step of setting the angle formed by the rotation axis of the p-axis and the rotation axis of the q-axis to θan, and holding the articulated robot in a measurement posture;
a second step of rotating the p-axis 180 degrees;
a third step of rotating the n-axis by twice θan;
A line segment connecting the coordinates of the measurement point in the measurement posture and the coordinates of the measurement point after performing the third step is derived, passes through the center coordinates of the derived line segment, and is orthogonal to the line segment. A fourth step of rotating the n-axis so that the coordinates of the measurement point overlap the straight line, and deriving the rotation angle when the coordinate of the measurement point overlaps the straight line as an error angle;
a fifth step of calibrating the n-axis origin position by adding the error angle to θan;
A controller for an articulated robot characterized by sequentially performing the steps. It has an n (n is a natural number greater than or equal to 2) axis, a p (p is a natural number less than n) axis, and a q (q is a natural number greater than n) axis, and the rotation axis of n axis is the rotation axis of p axis and q In the control device for an articulated robot configured to be orthogonal to the rotation axis of the shaft at the same point,
a first step of setting the angle formed by the rotation axis of the p-axis and the rotation axis of the q-axis to θan, and holding the articulated robot in a measurement posture;
a second step of rotating the p-axis 180 degrees;
a third step of rotating the n-axis by twice θan;
The distance between the coordinate of the measurement point in the measurement posture and the coordinate of the measurement point after performing the third step is ln, and the distance between the coordinate of the rotation center of the n-axis and the coordinate of the measurement point is Ln, when the error angle is Δθn,
Δθn = arcsin ((ln / 2) / Ln)
A fourth step of deriving the error angle according to the formula:
a fifth step of calibrating the n-axis origin position by adding the error angle to θan;
A controller for an articulated robot characterized by sequentially performing the steps.

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