JP3237241B2 - Laser head correction method for laser robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a laser head of a laser robot.

[0002]

2. Description of the Related Art There are various types of laser robots, one having a laser head mounted on the tip of a bending / extending arm that is rotatable about a pivot axis, and one that can move three-dimensionally using three orthogonal gantry axes. There is one in which a laser head is attached to the tip of a moving arm. The laser head includes a laser output nozzle and a servomotor for controlling the oscillation of the output nozzle, and these are mounted at predetermined positions of the laser head when assembling the laser robot.

[0003]

It is desirable that the axis of the output nozzle and the axis of the servomotor be completely aligned with the axis of the drive system of the laser robot. However, in practice, the degree of parallelism or verticality between the axes depends on mounting errors. Is out of order.
However, even if there is such an error, once the laser robot is taught, no problem occurs in the accuracy of the laser processing.

However, if the output nozzle or the servomotor is replaced after the teaching has been performed once, it is impossible to mount them with the exact same alignment as before the replacement, so that the teaching of the laser robot must be performed from scratch. You need to start over. This teaching work is very troublesome, and during that time, the laser robot cannot be used, so that the production efficiency is reduced.

It is an object of the present invention to provide a laser head correction method for a laser robot which can eliminate the need for re-teaching even if an error occurs in the mounting position due to replacement of an output nozzle or a servomotor.

[0006]

According to the present invention, there is provided a laser having a laser beam output nozzle.
Can rotate around three orthogonal axes X1, Y1, and Z1
Through three orthogonal axes X, Y, and Z
Laser mounted on a moving arm that is controlled and driven in three dimensions.
Laser robot from the laser head
Positive for detecting the beam irradiation point as XY coordinates
The movement sensor is disposed on the XY plane,
Direction on the position sensor when moved in the
The first trajectory of the beam irradiation point and the wrist
On the position sensor when rotated about one axis
The angle θ between the laser beam irradiation point and the second trajectory
1 and detects the angle θ1 as the corrected rotation angle of the Z1 axis.
Then, when the laser head is moved by H in the Z-axis direction,
Kino laser beam irradiation POI down on the position sensor
X and Y axes of the laser beam from the XY components of the
The inclination angles θ2 and θ3 of the directions are calculated respectively,
Laser head with angles θ2 and θ3 around X1 and Y1 axes
Head Correction of Laser Robot with Corrected Rotation Angle
Provide a way.

[0007]

The laser head of the laser robot is corrected so that the control axis in the central axis direction of the output nozzle is aligned with the center line of the actual laser beam. Even if there is an error in the installation position of the servo motor for controlling the output nozzle, simply re-correct the laser head to make the control axis of the laser nozzle's output nozzle installation center axis coincide with the center line of the actual laser beam. Since the above error can be eliminated, the control data of the laser robot by the first teaching can be used as it is without any change, so that the re-teaching of the conventional laser robot becomes unnecessary, and the operation rate of the laser robot is reduced. improves.

A laser robot having a moving arm that is controlled and driven three-dimensionally by three orthogonal axes of X, Y, and Z, and has a wrist that rotatably supports a laser head around three orthogonal axes. In the case of a laser robot, a first trajectory of a laser beam irradiation point formed by irradiating a laser beam to a position sensor disposed on an XY plane and moving a moving head in the X direction in that state, and moving the laser head to Y
When the angle θ1 between the laser beam irradiation point and the second trajectory formed when the laser head is rotated about one axis is the corrected rotation angle of the Z1 axis, and the laser head is moved by H in the Z axis direction. The inclination angles θ2 and θ3 of the laser beam in the X and Y axis directions are calculated from the XY components of the movement trajectory of the laser beam irradiation point on the position sensor, and the inclination angles θ2 and θ3 are calculated using the lasers around the X1 and Y1 axes. By using the corrected rotation angle of the head, even if an error occurs in the mounting position of the output nozzle of the laser beam or the servo motor for driving the output nozzle, the error can be eliminated. The control data of the laser robot can be used without any change, thus eliminating the need for re-teaching of the laser head as in the past. The operation rate of the user robot is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a drive system of a 6-axis orthogonal laser robot, in which 1 is a first movable body movable in the X-axis direction, 2 is a second movable body movable in the Y-axis direction, and 3 is Z It is a third moving body that can move in the axial direction. The third moving body is attached to a lower end of a moving arm 4 extending in the vertical direction.
The third moving body has an arm 5 extending in the X-axis direction, and a laser head 6 is attached to a tip of the arm 5. This laser head 6 has an X1 axis parallel to the X axis, a Y1 axis parallel to the Y axis, and a Z1 axis parallel to the Z axis (moving arm 4) with the rotation angle around the Z axis being 0 ° as shown in FIG. (Coaxial). And the laser head 6 is X
Axis, Y-axis and Z-axis can move in three orthogonal directions, and
It is rotatable about three orthogonal axes X1, Y1 and Z1. An output nozzle 7 is attached to a lower portion of the laser head 6 along a predetermined attachment center axis, and He-N is corrected from the lower end of the output nozzle 7 when the laser head 6 is corrected.
An e-laser beam 8 is irradiated.

Rotation axes X1, Y1, Z1 of laser head 6
The first servo motor 12 and the second servo motor 1 for turning and oscillating the output nozzle 7 as shown in FIG.
The third and third servomotors 14 are respectively mounted. Below the output nozzle 7 in the vertical direction, a position sensor 15 composed of a CCD is disposed horizontally detachably on an XY plane, and a laser beam irradiation point emitted from the output nozzle 7 is positioned at the time of laser head correction described later. It is configured to form an image on the sensor 15. A correction rotation angle calculation unit 16 and a robot driving unit 17 are sequentially connected to the position sensor 15, and information about the XY coordinates obtained from the position sensor 15 is corrected by the correction rotation angle calculation unit 1.
6 and the calculation result is input to the robot driving unit 17.
To the third servo motors 12 to 14 are controlled. The robot driving unit 17 also controls the movement of the first to third moving bodies 1 to 3.

Next, the procedure for correcting the laser head 6 will be described. This correction is performed before the first teaching of the laser robot having completed the assembly, and each time the output nozzle 7 and the first to third servomotors 12, 13, and 14 are replaced.

First, the laser head 6 is placed at a position of a rotation angle of 0 ° around the Z-axis (the state shown in FIG. 1).
By moving the moving body 1, the laser head 6 is moved in the X-axis direction, and a first trajectory 21 of the laser beam irradiation point is drawn on the position sensor 15 as shown in FIG.
Further, the second servo motor 13 is driven to rotate the laser head 6 around the Y1 axis, and the second trajectory 22 of the laser beam irradiation point is drawn on the position sensor 15. The straight line equation of the two trajectories 21 and 22 is calculated by the correction rotation angle calculation unit 16, and the calculation unit 16 also calculates the angle θ1 formed by the two trajectories 21 and 22. Although the angle θ1 is 0 in design, a slight angle occurs due to an error in mounting the laser head 6. The correction rotation angle calculation unit 16 calculates a correction rotation angle (-θ1) of the Z1 axis so as to cancel the angle θ1, and the robot driving unit 17 uses the third servo motor 14 based on the correction rotation angle (-θ1). Is rotated by -θ1.

The mounting error in the laser head 6 is not limited to the angle θ1 described above. An attachment error of the output nozzle 7 around the X1 and Y1 axes may also occur. Therefore, the following correction is performed. First, as shown in FIG.
While maintaining the reference height H1 of the third servo motor 14
To rotate the output nozzle 7 once around the Z1 axis.
Next, the third moving body 3 is moved upward by a predetermined distance H along the Z axis, and the output nozzle 7 is similarly rotated once. When the output nozzle 7 is inclined with respect to a vertical line (Z axis or Z1 axis), a locus of a double circle is drawn on the position sensor 15 by the laser beam irradiation point. The inner circle is drawn first, and the outer circle is drawn next. Start point of rotation of laser head 6 around Z1 axis (rotation angle 0 °)
The points P1 and P2 of the laser beam irradiation points of the two circles are Δx and Δy mutually as shown in FIGS.
Assuming that the output nozzles 7 are spaced apart from each other, the mounting error of the output nozzle 7 around the X1 axis and the Y1 axis is calculated by the corrected rotation angle calculation unit 16 from these Δx, Δy, and H. That is, Y1
The error about the axis is the inclination angle θ2 of the laser beam on the XZ plane as shown in FIG. 6A = tan ⁻¹ (Δx / H).
The error about the X1 axis is the inclination angle θ3 of the laser beam on the YZ plane as shown in FIG. 6B = tan ⁻¹ (Δy / H). The corrected rotation angle calculation unit 16 calculates these θ2 and θ3, and corrects and rotates the second servo motor 13 by −θ2.
The first servo motor 12 is corrected and rotated by −θ3. As a result, the output nozzle 7 is made perpendicular to the horizontal plane, and the mounting error in the inclination direction is eliminated.

Next, when the third servo motor 14 is driven to rotate the output nozzle 7 once, a circle having a radius R is drawn on the position sensor 15 as shown in FIG. The value of R indicates an offset amount of the output nozzle 7 with respect to the Z1 axis of the rotation center, and a certain value is determined by design. Therefore, the correction value for eliminating the error between the R and the design value is calculated by the correction rotation angle calculation unit 1.
Then, the correction value is fed back to the robot drive unit 17.

After performing the above correction, the first teaching of the laser robot is performed. Thereafter, when the output nozzle 7 and the first to third servomotors 12, 13, and 14 are replaced, the above correction is repeated each time. As a result, the mounting state before the replacement is accurately restored, and therefore, the processing position can be always kept constant by the first teaching data.

Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible.
The present invention is also applicable to a laser robot in which a laser head is attached to the tip of a bending arm that can bend and extend. The present invention is basically characterized in that the control axis in the direction of the installation center axis of the laser output nozzle is corrected so as to coincide with the center line of the actual laser beam. A method is proposed, wherein the correction method of claim 1 includes other correction methods that meet the objects and effects of the present invention.

[0017]

As described above, according to the present invention, even if an error occurs in mounting the output nozzle and the servo motor for controlling the output nozzle, the control axis in the direction of the center axis of the output nozzle mounting of the laser robot is adjusted to the actual laser beam. By correcting so as to match the center line, the error can be eliminated and the mounting state can be always kept constant, so that the first teaching data of the laser robot can be used as it is without being changed. This eliminates the need for re-teaching, thus improving the operating rate of the laser robot.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a drive system of a laser robot.

FIG. 2 is a schematic diagram of a drive system of a laser output nozzle.

FIG. 3 is a diagram showing first and second trajectories of a laser beam irradiation point on a position sensor.

FIG. 4 is a perspective view showing a circle drawn on a position sensor when the laser head is turned around the Z1 axis.

FIG. 5 is a plan view of the same.

6A is a diagram illustrating a tilt of a laser beam on an XZ plane, and FIG. 6B is a diagram illustrating a tilt of a laser beam on a YZ plane.

[Description of Signs] 1 First moving body 9 Wrist 2 Second moving body 12-14 Servo motor 3 Third moving body 15 Position sensor 4 Moving arm 16 Correction rotation angle calculation section 5 Arm 17 Correction drive section 6 Laser head 21 first trajectory 7 output nozzle 22 second trajectory 8 laser beam

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 26/08 B23K 26/00 B23K 26/04 B25J 9/10

Claims (1)

(57) [Claims] 1. A laser head having a laser beam output nozzle is supported by three orthogonal axes of X, Y, and Z via a wrist portion rotatably supporting the laser head around three orthogonal axes of X1, Y1, and Z1. In a laser robot attached to a moving arm controlled and driven in a three-dimensional direction, a position sensor for detecting an irradiation point of a laser beam emitted from the laser head as XY coordinates is provided on an XY plane, and the moving head is moved in the X direction. And a second trajectory of the laser beam irradiation point on the position sensor when the wrist is rotated about the Y1 axis. Is detected, and the angle θ1 is detected as Z1.
The rotation angle of the axis, and the inclination angle of the laser beam in the X and Y axis directions from the XY component of the movement locus of the laser beam irradiation point on the position sensor when the laser head is moved by H in the Z axis direction. A method for correcting a laser head of a laser robot, wherein θ2 and θ3 are respectively calculated, and the inclination angles θ2 and θ3 are used as correction rotation angles of the laser head around the X1 and Y1 axes.