JP2564143B2 - Method and apparatus for correcting position deviation of articulated robot - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for correcting the deviation of the tip position of a tool or the like of an articulated robot when the deviation occurs from the original position.

[Conventional technology and problems]

The articulated robot has, for example, six axes, and is configured to cause a tool attached to the tip axis to perform a predetermined work by moving each axis. The control circuit of this robot stores the reference position of the tip axis, that is, the origin, and moves the tool along a predetermined path with reference to this origin. Therefore, it is important for the performance of the articulated robot to store the position of each axis in the control circuit when the tip axis returns to the origin before the robot operates.

However, conventionally, the adjustment work for positioning the tip axis at the origin has been performed for each axis in order from the axis closer to the robot base, by mounting a level for exclusive use on each axis. Therefore, the adjustment work takes a long time, and the error of the axis close to the fixed base of the robot affects the position of the tip axis.As a result, the position accuracy of the tip axis deteriorates, and a jig is required for each axis. There is a problem that

In view of the above points, the present invention is a position deviation correcting method and apparatus in which positioning adjustment of the tip axis to the origin is performed in a short time and with high accuracy, and a jig need not be provided for each axis. It is made for the purpose of providing.

Japanese Unexamined Patent Publication No. 61-253507 discloses a method and apparatus for teaching the position of an industrial robot, which is performed by forcibly positioning the apical centering axis at a teaching point, and Japanese Unexamined Patent Publication No. 60-9678. The publication discloses a tool correction method for an articulated robot which is performed by inserting a tool into a jig.

[Means for solving problems]

The position deviation correction method for an articulated robot according to the present invention is
A method of returning the tip axis to the origin position by a gauge having a needle-like protrusion attached to the tip axis of an articulated robot, in which the tip of the needle-like protrusion coincides with a fixed side reference point. It is characterized in that the gauge is set horizontally while maintaining the state in which the tip end coincides with the reference point, and the position of each axis of the robot is stored.

Further, the position deviation correcting device for an articulated robot according to the present invention is used directly for carrying out the above-mentioned method, and is attached to the tip shaft of the articulated robot and is eccentric to the attachment part to the tip shaft and is perpendicular to it. A gauge having a needle-like protrusion extending downward and a gauge having a needle-like protrusion that is different
A level that is placed along the above direction, a means for horizontally positioning the gauge while maintaining the state in which the tip of the needle-like protrusion is aligned with the reference point on the fixed side, and each of the robots. And a means for storing the position of the shaft.

〔Example〕

 The present invention will be described below with reference to illustrated embodiments.

FIG. 1 shows a tip shaft 11 and its vicinity of a multi-joint robot to which an embodiment of the present invention is applied. Flange of tip shaft 11
An automatic tool changer (ATC) attached to 13 is a general-purpose tool gripping mechanism and supports a normal tool during robot operation, but can be equipped with a position deviation correction work gauge 21 shown in the figure. The robot has, for example, six axes (not shown) including the tip axis 11. The axes are connected by joints (not shown), and are rotationally moved by drive motors (not shown), respectively, so that the tool or gauge 21 attached to the ATC 12 can be moved to a desired position in 32 dimensions. Be done. The robot controller 14 is for moving each axis to a predetermined rotation angle position, or for moving a tool or the like to a predetermined position.
The tool is moved along a predetermined path by the control of the built-in control circuit, and the gauge is moved to an arbitrary position by the operation of various switches provided on the outer surface during the position deviation work.

2 to 4 show the gauge 21 and its mounting structure. Gauge 21 is a rectangular plate 22 and this plate 22
And a needle-like protrusion 23 extending vertically downward from the lower surface of the.
The top surface of plate 22 is bolt 24 as shown in FIG.
It is fixed to the lower surface of the ATC 12 via the ATC 12, that is, it is fixed to the tip shaft 11 (FIG. 1) via the ATC 12. Further, the upper surface of the plate 22 may be fixed to the flange 13 of the tip shaft 11 via a bolt 24, as shown in FIG. Needle-like protrusion 23
Is provided at a portion eccentric from the portion where the plate 22 is attached to the tip shaft 11. The upper end 25 of the needle-like protrusion 23 is fitted into a hole 26 formed in the plate 22, and is fixed in a state where the flange 27 is in contact with the lower surface of the plate 22.

At the time of position deviation correction work, as shown in FIG. 1, two spirit levels 31, 32 are placed on the upper surface of the plate 22 of the gauge 21. These spirit levels 31 and 32 are provided along two mutually different directions. For example, one spirit level 31 is placed along the A direction in the figure, and the other spirit level 32 is perpendicular to the A direction.
Placed along the direction. It is preferable that the A direction and the B direction are orthogonal to each other in this way. Further, only one level may be provided, and in this case, the level may be first placed along the A or B direction, and then placed along the other orthogonal direction.

In the present embodiment, a reference point P is marked on the shuttle base 15 which is a fixed portion of a shuttle conveyor (not shown) in order to correct the positional deviation of the tip shaft 11. The reference point P is within the operation range of the robot, and the tip of the needle-like protrusion 23 of the gauge 21 attached to the tip shaft 11 can come into contact with the reference point P. The reference point P is not necessarily the shuttle base 15
It does not need to be provided on the robot, and may be provided on any part as long as it is not displaced with respect to the fixed base of the robot.

5 and 6 show the procedure for correcting the position deviation of the tip shaft 11.

FIG. 5 shows a preparation procedure in which the robot first stores the reference point P. First, the gauge 21 is attached to the ATC 12, for example (step 101), but if the ATC 12 is not used, the tip shaft 11
Mount directly on flange 13 of. Next, the tip end of the needle-like protrusion 23 of the gauge 21 is brought into contact with the reference point P so that they coincide with each other (step 102). This is done by rotating the drive motors for each axis of the robot via the robot controller 14. Normally, in this state, the plate 22 of the gauge 21 is inclined, and then the plate 22 is made horizontal while maintaining the state in which the tip of the needle-like protrusion 23 coincides with the reference point P (step 103). This is also performed by rotating the drive motor via the robot controller 14. Then, the tip of the needle-like protrusion 23 coincides with the reference point P, and the plate 22
The robot is taught the position of the reference point P, that is, the (x, y, z) coordinates in a state in which is horizontal (step 104). That is, the position of the reference point P in this state is stored in the control circuit of the controller 14. At the same time, the position of each axis of the robot, that is, the rotational angle position of each drive motor is stored in the control circuit (step 105). As described above, the robot stores the reference point P, and thereafter, the robot operates with the reference point P as a reference and performs various operations.

If there is a possibility that the axis deviation of the robot has occurred, the deviation is corrected by the procedure shown in FIG. First, the axial deviation of the first shaft (not shown) connected to the fixed base of the robot is corrected (step 201). This is the same as the conventional one
This is done by aligning the reference holes formed in the shaft and the fixed base with each other and inserting a pin into the reference holes. Next, the gauge 21 is attached to the ATC 12 of the robot in the same manner as in step 101 above (step 202), and the robot controller 14 is set so that the tip of the needle-like protrusion 23 coincides with the reference point P taught in step 104 above. The respective drive motors are rotated through (step 203). However, when the robot is axially deviated, as shown in FIG. 7, the plate 22 of the gate 21 is inclined and the tip of the needle-shaped protrusion 23 is deviated from the reference point P. Then, next, the robot controller 14 is operated to rotate the drive motors of the respective axes so that the tips of the needle-like protrusions 23 coincide with the reference point P (step 204). However, in this state, the normal plate 22 is inclined, and then the controller 14 is operated to adjust the rotational angle position of each drive motor in the same manner as in step 103 above, and the tip of the needle-like protrusion 23 is set as a reference point. The plate 22 is set horizontally while maintaining the state of being in contact with P (step 205). Note that the first axis must not be displaced with respect to the fixed base during the execution of these steps 204,205.

By the above execution, the robot is set at the position of the approximate reference point P, but the tip of the needle-like protrusion 23 is actually slightly deviated from the reference point P. Therefore, this deviation is visually inspected (step 206), and if the deviation range is within the allowable error, the process proceeds to the next step, but if the deviation is large, steps 203 to 205 are repeated. Here, in step 203, the tip of the needle-shaped protrusion 23 is made to coincide with the reference point P via the robot controller 14. When the plate 22 is in the horizontal state and the tip of the needle-like protrusion 23 coincides with the reference point P by executing steps 203 to 205, the rotation angle position of the drive motor of each axis of the robot at this time is determined by the robot. controller
Remember to 14. At this time, the original rotation angle position is also stored, and the control circuit thereafter controls the position of the robot by using the difference between these rotation angle positions as a correction value.
Thus, the axis deviation of the robot is corrected, and the control accuracy of the tool attached to the tip shaft 11 is improved.

The work time for correcting the position deviation of the present embodiment shown in FIGS. 5 and 6 is much shorter than the conventional one, and it took about 20 minutes instead of about one hour conventionally. Further, in this embodiment, since the position deviation of each axis is corrected by adjusting the attitude and position of the gauge attached to the tip axis, it is not necessary to provide a jig for each axis, and it is possible to reduce the number of parts. Corrections can be made.

〔The invention's effect〕

As described above, according to the present invention, the axis deviation of the robot can be corrected in a short time with a small number of parts, and the axis deviation can be corrected with high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a robot to which an embodiment of the present invention is applied, FIG. 2 is a plan view showing a plate of a gauge, and FIG. 3 is a side view showing a state in which the gauge is attached to an ATC, FIG. 4 is a side view of an essential part showing a state where the gauge is directly attached to the robot tip shaft, FIG. 5 is a flow chart showing a preparation procedure for position deviation correction, and FIG. 6 is a flow chart showing position deviation correction work. FIG. 7 is a perspective view showing a gauge in the position deviation correcting work. 11 ... Tip axis, 21 ... Gauge, 23 ... Needle-like protrusion, P ... Reference point.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Asada 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Kyoo Ishiguro 1, Toyota Town, Aichi Prefecture Toyota Motor Co., Ltd. ( 72) Inventor Kaneo Ito 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Seiichiro Miyajima 1-1-1, Asahi Town, Kariya City, Aichi Toyota Koki Co., Ltd. 1-1-1 Asahi-cho, Kariya city, Aichi Toyota Koki Co., Ltd. (56) Reference JP 61-253507 (JP, A) JP 60-9678 (JP, A) JP 58-160086 ( JP, A) JP 62-27802 (JP, A) JP 58-132493 (JP, A)

Claims (2)

(57) [Claims] 1. A method of returning the tip axis to an origin position by a gauge having a needle-like projection attached to the tip axis of an articulated robot, wherein the tip of the needle-like projection is a fixed side reference. A position deviation correcting method for an articulated robot, characterized in that the gauge is set horizontally while maintaining the state where the tip coincides with a reference point and the tip thereof coincides with a reference point, and the position of each axis of the robot is stored. 2. A gauge having a needle-like protrusion that is attached to a tip shaft of an articulated robot and is eccentric to a portion attached to the tip shaft and extends vertically downward, and a gauge on a horizontal upper surface of the gauge. A level that is placed along two or more directions, a means for horizontally positioning the gauge while maintaining the state in which the tips of the needle-shaped protrusions are aligned with the fixed-side reference point, and the robot A device for correcting the position deviation of an articulated robot, comprising: means for storing the position of each axis.