JPH06142967A - Method for correcting laser beam head of laser beam robot - Google Patents

Abstract

PURPOSE:To provide a method for correcting a laser beam head unnecessary for reteaching a laser robot even when setting errors occur in an output nozzle or a servo motor. CONSTITUTION:A position sensor 15 to detect an irradiating point of a laser beam emitted from a laser head 6 as an X-Y coordinate, is arranged on an X-Y plane. An angle theta1 formed by a 1st locus of the irratiation point on a position sensor 15 when the laser beam head 6 is moved in the direction of X axis, and a 2nd locus 22 of the irradiation point of the laser beam on the position sensor 15 when a wrist part 9 is rotated around a Y1 axis is detected and this angle theta1 is defined as a corrective rotational angle of Z1. Further, inclination angles theta2 and theta3 in the directions of the X axis and the Y axis are calculated at a corrective rotational angle arithmetic unit 16 from an XY component of a moving locus of the irradiation point of the laser beam on the position sensor 15 when the laser beam head 6 is moved by H in the Z axis direction.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art There are various types of laser robots. A laser head is attached to the tip of a bending / extending arm which can be freely rotated by a turning axis, and it can be moved in three dimensions by a gantry type orthogonal three axes. For example, there is one in which a laser head is attached to the tip of the moving arm. The laser head is provided with 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 the laser robot is assembled.

[0003]

It is desirable that the axes of the output nozzle and the servo motor be perfectly aligned with the axes of the drive system of the laser robot, but in reality, due to mounting errors, the parallelism or perpendicularity between the axes is high. Madness has occurred.
However, even if such a discrepancy occurs, once the laser robot is taught, there will be no problem in the accuracy of laser processing.

However, if the output nozzle or the servomotor is replaced after the teaching once, it is impossible to mount them in exactly the same alignment as before the replacement in the strict sense, so that the teaching of the laser robot is started from the beginning. I need to start over. This teaching work is very time-consuming, and since the laser robot cannot be used during that time, the production efficiency also decreases.

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 of the output nozzle or the servo motor due to replacement or the like.

[0006]

In order to solve the above-mentioned problems, the present invention provides a laser robot for mounting a laser head having a laser beam output nozzle on a robot which can be controlled and driven in a three-dimensional direction to process a workpiece. The tilt direction and angle of the center line of the actual laser beam with respect to the control axis line of the output nozzle mounting center axis direction of the laser robot is measured, and based on the tilt direction and angle, the output nozzle mounting center axis direction of the laser robot is measured. There is provided a laser head correction method for a laser robot characterized by correcting a laser head so that a control axis line coincides with an actual center line of a laser beam.

Further, according to the present invention, a laser head having an output nozzle for a laser beam is provided with three orthogonal X1, Y1 and Z1.
X, through the wrist that supports the axis of rotation
In a laser robot mounted on a moving arm that is controlled and driven in three dimensions by three orthogonal axes of Y and Z, a position sensor that detects an irradiation point of a laser beam emitted from the laser head as XY coordinates is arranged on an XY plane. Then, the first locus of the laser beam irradiation point on the position sensor when the moving head is moved in the X direction and the laser on the position sensor when the wrist portion is rotated around the Y1 axis. On the position sensor when the angle θ1 formed by the beam irradiation point and the second locus is detected and the angle θ1 is set as the correction rotation angle of the Z1 axis and the laser head is moved by H in the Z axis direction. The tilt angles θ2 and θ3 of the laser beam in the X- and Y-axis directions are calculated from the XY components of the movement locus of the laser beam irradiation point of The degree θ2 and θ3 X1 and Y1
Provided is a laser head correction method for a laser robot in which a correction rotation angle of a laser head around an axis is set.

[0008]

The laser head of the laser robot is corrected so that the control axis of the output nozzle mounting central axis coincides with the actual center line of the laser beam, and the laser robot is taught once in this state. Even if there is an error in the mounting position of the servo motor for controlling the output nozzle, the laser robot head is re-corrected so that the control axis of the output nozzle mounting center axis of the laser robot matches the center line of the actual laser beam. Since the above error can be eliminated by just using it, it can be used as it is without changing the control data of the laser robot by the first teaching. Therefore, the re-teaching of the conventional laser robot becomes unnecessary, and the operation rate of the laser robot can be reduced. Is improved.

A laser robot having a moving arm which is three-dimensionally controlled and driven by three orthogonal X, Y, and Z axes, and has a wrist portion for rotatably supporting the laser head around the three orthogonal axes. In the case of a laser robot, a position sensor arranged on the XY plane is irradiated with a laser beam, and in that state, a first locus of a laser beam irradiation point formed by moving the moving head in the X direction and the laser head in the Y direction.
When the angle θ1 formed by the second locus of the laser beam irradiation point formed when the laser head is rotated about the 1-axis is the corrected rotation angle of the Z1-axis, and the laser head is moved by H in the Z-axis direction. The tilt angles θ2 and θ3 of the laser beam in the X- and Y-axis directions are calculated from the XY components of the movement locus of the laser beam irradiation point on the position sensor, and the tilt angles θ2 and θ3 are measured around the X1 and Y1 axes. Even if an error occurs in the mounting position of the output nozzle of the laser beam or the servo motor for controlling the output nozzle drive, the error can be eliminated by setting the correction rotation angle of the head. It can be used as it is without changing the control data of the laser robot. The operating rate of the robot is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 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, where 1 is a first moving body that can move in the X-axis direction, 2 is a second moving body that can move in the Y-axis direction, and 3 is Z. It is a third movable body that is movable in the axial direction. This third moving body is attached to the 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 the tip of this arm 5. As shown in FIG. 1, the 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 when the rotation angle around the Z axis is 0 °). Is supported by a wrist portion 9 which has And the laser head 6 is X
Can move in three orthogonal directions of axis, Y axis and Z axis, and
It is rotatable about three orthogonal axes of the X1, Y1, and Z1 axes. An output nozzle 7 is attached to a lower portion of the laser head 6 along a predetermined attachment center axis line, and the He-N is adjusted from the lower end of the output nozzle 7 when the laser head 6 is corrected.
The e-laser beam 8 is irradiated.

Rotating axes X1, Y1, Z1 of the laser head 6
2 includes a first servo motor 12 and a second servo motor 1 for rotating and swinging the output nozzle 7, as shown in FIG.
The 3rd and 3rd servomotors 14 are attached, respectively. A position sensor 15 composed of a CCD is detachably arranged horizontally on the XY plane below the output nozzle 7 in the vertical direction, 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. The correction rotation angle calculation unit 16 and the robot drive unit 17 are sequentially connected to the position sensor 15, and the information about the XY coordinates obtained from the position sensor 15 is used as the correction rotation angle calculation unit 1.
6 and the calculation result is input to the robot drive unit 17, and the first signal is input by the signal from the robot drive unit 17.
The third servo motors 12 to 14 are controlled. The robot drive unit 17 also controls the movement of the first to third moving bodies 1 to 3.

Next, the correction procedure of the laser head 6 will be described. This correction is performed before the first teaching of the laser robot which has been assembled, and each time the output nozzle 7 and the first to third servomotors 12, 13, 14 are replaced.

To make the correction, first, the laser head 6 is placed at a position where the rotation angle is 0 ° around the Z axis (the state of FIG. 1), and in this state the first
By moving the moving body 1, the laser head 6 is moved in the X-axis direction, and the first locus 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 locus 22 of the laser beam irradiation point is drawn on the position sensor 15. The linear equation of both loci 21 and 22 is calculated by the correction rotation angle calculation unit 16 and the angle θ1 formed by both loci 21 and 22 is also calculated by the same calculation unit 16. This angle θ1 is 0 in design, but a slight angle is generated due to an error in mounting the laser head 6. The corrected rotation angle calculation unit 16 calculates the correction rotation angle (−θ1) of the Z1 axis so as to cancel the angle θ1, and the robot drive unit 17 calculates the corrected rotation angle (−θ1) based on the corrected rotation angle (−θ1). Is rotated by -θ1.

The mounting error in the laser head 6 is not limited to the angle θ1 described above. A mounting error of the output nozzle 7 around the X1 and Y1 axes may also occur. Therefore, the following correction is performed. First, the laser head 6 is
Of the third servomotor 14 while maintaining the reference height H1 of
Is driven to rotate the output nozzle 7 once around the Z1 axis.
Next, the third moving body 3 is moved upward along the Z axis by a predetermined distance H, and the output nozzle 7 is similarly rotated once. When the output nozzle 7 is tilted with respect to the 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 the laser head 6 around the Z1 axis (rotation angle 0 °)
The points P1 and P2 of the laser beam irradiation points of both circles in the circle are Δx and Δy with respect to each other as shown in FIGS.
Assuming that they are separated from each other, the correction rotation angle calculation unit 16 calculates the mounting error of the output nozzle 7 around the X1 axis and the Y1 axis from these Δx, Δy, and H. That is, Y1
The error about the axis is the inclination angle θ2 = tan ⁻¹ (Δx / H) of the laser beam on the XZ plane as shown in FIG.
The error around the X1 axis is the inclination angle θ3 = tan ⁻¹ (Δy / H) of the laser beam on the YZ plane as shown in FIG. 6B. The corrected rotation angle calculation unit 16 calculates these θ2 and θ3, and correctively rotates the second servo motor 13 by −θ2.
The first servomotor 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 servomotor 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 the 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, a correction value that eliminates the error between the R and the design value is set as the correction rotation angle calculation unit 1
6 is calculated, and this 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. After that, when the output nozzle 7 or the first to third servomotors 12, 13, 14 are replaced, the above correction is repeated each time. As a result, the mounting state before replacement is accurately restored, and therefore the machining position can always be made constant by the first teaching data.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications can be made. For example, the present invention is a 6-axis orthogonal laser robot,
It can also be applied to a laser robot having a laser head attached to the tip of a bending arm that can bend and stretch. Further, the present invention is basically characterized in that the control axis line in the mounting central axis direction of the laser output nozzle is corrected so as to coincide with the actual center line of the laser beam. A method is proposed, and the correction method of claim 1 also includes other correction methods that meet the objects and effects of the present invention.

[0018]

As described above, according to the present invention, even if the output nozzle or the servo motor for controlling the output nozzle causes a mounting error, the control axis of the output nozzle mounting center axis of the laser robot is controlled by the actual laser beam. By correcting so as to match the center line, the above error can be eliminated and the mounting state can be made constant at all times, so it is possible to use it without changing the first teaching data of the laser robot. Such re-teaching becomes unnecessary, and the operating rate of the laser robot can be improved.

[Brief description of 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 loci of laser beam irradiation points on a position sensor.

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

FIG. 5 is a plan view of the same.

FIG. 6A is a diagram showing the inclination of the laser beam on the XZ plane, and FIG. 6B is a diagram showing the inclination of the laser beam on the YZ plane.

[Explanation of symbols]

1 1st moving body 9 Wrist part 2 2nd moving body 12-14 Servo motor 3 3rd moving body 15 Position sensor 4 Moving arm 16 Corrected rotation angle calculation part 5 Arm 17 Correction drive part 6 Laser head 21 1st locus 7 Output nozzle 22 Second locus 8 Laser beam

Claims (2)

[Claims] 1. A laser robot for processing a workpiece by attaching a laser head having a laser beam output nozzle to a robot capable of controlling and driving in three dimensions, wherein a laser robot has a control axis in a direction of an output nozzle attachment center axis of the laser robot. To measure the tilt direction and angle of the center line of the actual laser beam, and to match the control axis of the output robot mounting center axis direction of the laser robot with the center line of the actual laser beam based on the tilt direction and angle. A method for correcting a laser head of a laser robot, which comprises correcting the laser head. 2. A laser head having a laser beam output nozzle is rotatably supported around three orthogonal axes of X1, Y1 and Z1 via a wrist portion, and the three orthogonal axes of X, Y and Z are used. In a laser robot mounted on a moving arm controlled and driven in three dimensions, a position sensor that detects an irradiation point of a laser beam emitted from the laser head as XY coordinates is arranged on an XY plane, and the moving head is moved in the X direction. Trajectory of the laser beam irradiation point on the position sensor when it is moved to the second position, and second trajectory of the laser beam irradiation point on the position sensor when the wrist is rotated around the Y1 axis. The angle θ1 formed by
The corrected rotation angle of the axis is used, and the tilt angle of the laser beam in the X and Y axis directions from the XY component of the movement trajectory of the laser beam irradiation point on the position sensor when the laser head is moved by H in the Z axis direction. A laser head correction method for a laser robot in which θ2 and θ3 are respectively calculated, and the tilt angles θ2 and θ3 are used as correction rotation angles of the laser head around the X1 and Y1 axes.