JP2662679B2 - Articulated laser machining robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an articulated laser machining robot used for welding, cutting, and surface modification of a three-dimensional object with a laser beam. And a structure in which the number of mirrors guided to the position is reduced.

[0002]

2. Description of the Related Art In recent years, work methods for welding, cutting, and surface modification of three-dimensional objects using a laser beam have begun to be adopted. This is because work efficiency and work accuracy are improved.

In order to set the operation of the final end of the machining head in an articulated laser machining robot to an arbitrary angle at an arbitrary position selected in a three-dimensional space, see, for example,
As disclosed in JP-A-2-130788 and schematically shown in FIG. 10, at least five movable axes (J1, J2, J3, J4) are provided.
, J5) required. In the figure, J1, J2, J3,
The J4 and J5 axes are all rotating axes. The same applies to the articulated laser machining robot for three-dimensional work. In the case where the path of the laser beam is incorporated into the mechanical components of the robot, conventionally, the laser beam is applied from the side surface Bi1 (or the bottom portion Bi2) of the robot installation table. Is incident and guided to the final end B0 of the machining head, the angle at which each axis intersects is fixed, and mirrors (m0 to m5, Pm) are provided at each intersection (a0 to a6 or a1 to a6) on the incident side. The mirror reflecting surface is oriented so that the bisector of the angle formed by the axis opposite to the axis and the perpendicular to the mirror reflecting surface is oriented so that the mounting angle does not change. Therefore, at least five mirrors are required for changing the direction of the laser beam.

In general, a device using laser light requires a large number of mirrors unless the arrangement of the mirrors is taken into consideration. These large number of mirrors cause attenuation of transmitted energy, and
Adjustment of the mirror mounting position and angle when adjusting the optical axis,
The replacement frequency increases. Improvements in this respect are also desired for articulated laser machining robots.

On the other hand, there has been proposed a laser machining robot in which the number of mirrors is minimized not in the articulated type but in the polar coordinate type in order to reduce the number of mirrors (JP-A-1-273688). This laser processing robot has a configuration as shown in FIGS. FIG. 11 shows a mirror-movable polar coordinate laser machining robot. The swivel column 2 rotates about a first axis J1 in a direction perpendicular to the mounting table 1, and the second arm 4 has a telescopic shaft 4 which is telescopic with respect to the first arm 3 along a third axis J3. Is composed. The first arm 3 is held so as to be able to descend about a second axis J2 provided on the revolving column 2. The three axes (first axis J1 and second axis J2)
, The third axis J3) intersect at the intersection a1. A first hollow head 5 is incorporated in the distal end of the telescopic shaft 4. The first hollow head 5 rotates around a fourth axis J4 concentric with the third axis J3, and incorporates a second hollow head 6 perpendicular to the fourth axis J4. The second hollow head 6 pivots about a fifth axis J5 perpendicularly intersecting the fourth axis J4, and the laser beam formed on the outer periphery of the axis J0 perpendicularly intersecting the fifth axis J5. It is constituted by a nozzle 7 which is an emission port to a workpiece. In this robot, the laser beam Bi1 incident on the intersection a0 with the first axis J1 from the side surface of the mounting table 1 (the laser beam Bi concentrically incident on the lower first axis J1 of the mounting table 1 is Bi2 ) Is reflected concentrically with the first axis J1 by the mirror m0, and is guided to the intersection a1 of three axes of the first axis J1, the second axis J2, and the third axis J3. The laser beam guided to the intersection a1 is reflected by the mirror m1 concentrically with the third and fourth axes J3 and J4, and is reflected by the mirror m2 incorporated inside the first hollow head 5 concentrically with the fifth axis J5. Then, it is guided to the intersection point a3 of the fifth axis J5 and the axis J0 perpendicular to the fifth axis. The laser beam guided to the intersection a3 is
The light is reflected and condensed by a parabolic mirror Pm incorporated in the hollow head 6, and is emitted outside the robot as a laser beam B0 by a nozzle 7 incorporated coaxially with the axis J0 around the axis J0. The inside of the first hollow head 5 and the second hollow head 6 has a structure through which a laser beam can pass.

When the above configuration is mechanically simplified, FIG.
The mirror m0 has a reflecting surface including an intersection a0 with the first axis J1, and the reflecting surface is defined by an intersection a1 of three axes of a first axis J1, a second axis J2, and a third axis J3. The mirror m1 has a reflecting surface including the intersection a1 of the first axis J1, the second axis J2, and the third axis J3, and the reflecting surface is concentric with the third axis J3. The arm 3 is rotatably mounted toward the intersection a2 between the fourth axis J4 and the fifth axis J5. The mirror m2 makes the reflecting surface include the intersection a2 of the fourth axis J4 and the fifth axis J5, and directs the reflecting surface to the intersection a3 of the fifth axis J5 and the axis J0 perpendicular to the fifth axis. First
Mounted inside the hollow head 5, the parabolic mirror Pm includes the intersection point a3 between the fifth axis J5 and the axis J0 on the reflecting surface, and the reflecting surface is oriented on the axis J0 with the reflecting surface facing the axis J0. Surface mirror Pm
Attach so that the focus of the comes.

The mirror m1 is provided with a mirror angle setting mechanism 10 for making the normal passing through the intersection a1 coincide with the bisector of the angle formed by the laser beam incident on the mirror m1 and the third axis J3. I have. FIG. 13 shows a mirror angle setting mechanism 10 for the mirror m1, which is constructed as follows. 10a
Is a mirror mounting shaft, which is rotatably held by the mirror mounting frame 9d. The mirror mounting shaft 10a is rotated by a mirror angle setting rotation servomotor 10b. The rotation angle of the mirror mounting shaft 10a, that is, the turning angle of the mirror m1, is detected by a mirror rotation angle detector 10c.

[0008]

However, in the case of a mirror-movable polar coordinate type laser machining robot as disclosed in Japanese Patent Application Laid-Open No. 1-273688, it is possible to reduce the number of mirrors. The range cannot be made large. On the other hand, JP-A-62-130788
In the case of an articulated laser machining robot as disclosed in Japanese Unexamined Patent Publication, the operating range of the robot can be increased, but the number of mirrors increases.

Accordingly, an object of the present invention is to provide a mirror-movable articulated laser machining robot having both features, that is, having a large robot operating range and a small number of mirrors.

[0010]

In order to achieve the above object, an articulated laser machining robot according to the present invention comprises:
A swivel column that rotates about an axis is installed on a mounting table, a first arm that elevates around a second axis is connected to the swivel column, and a second arm that elevates about a third axis is a first arm. A laser beam transmission path connected to the tip and having a center passing through the rotation center of the third axis and forming the same plane as the center of the first axis is provided inside the second arm, and a laser beam incident concentrically with the first axis Is reflected by a mirror provided at the intersection of the first axis and an extension of the center of the laser beam transmission path, and is guided to the laser beam transmission path.

A mirror angle setting mechanism for following the mirror such that a bisector of an angle formed between the first axis and a center axis of the laser beam transmission path coincides with a perpendicular on a mirror reflecting surface; A mirror position setting mechanism is provided for following the amount of change in the position of the intersection between the first axis and the central axis of the laser beam transmission path due to the angle change of the first arm and the second arm. Further, a first hollow head that rotates around a fourth axis that is coaxial with the axis of the second arm is attached to the tip of the second arm, and the first hollow head is rotated around a fifth axis that is perpendicular to the fourth axis. The second hollow head that rotates is attached to
A second mirror that reflects the laser beam is arranged at the intersection of the axes, and the laser beam is guided to the nozzle.

[0012]

The mirror provided at the intersection of the first axis of the center of rotation of the revolving column and the extension of the center of the second arm follows the angle change caused by the raising and lowering of the first and second arms.
The laser beam incident concentrically with the first axis is guided to a laser beam transmission path provided in the second arm.

[0013]

FIG. 1 is a perspective view of an articulated laser machining robot showing one embodiment of the present invention. This articulated laser machining robot (hereinafter simply referred to as a robot) includes an installation table 1, a rotating column 2, a first arm 3, a second arm 4, and a first arm 4.
A hollow head 5 and a second hollow head 6 are provided. The revolving column 2 rotates around a first axis J1 perpendicular to the mounting table 1, and incorporates a first arm 3. The first arm 3 descends around the second axis J2, and the second arm 4 is incorporated at the tip. The second arm 4 has a third axis J
3, the first hollow head 5 is incorporated at the tip. The first hollow head 5 rotates around a fourth axis J4 concentric with the axis of the laser beam transmission path 8 provided inside the second arm 4, and the second hollow head 6 is perpendicular to the fourth axis J4. It has been incorporated. The second hollow head 6 pivots around a fifth axis J5 formed on the same plane as the fourth axis J4, and the axis J formed on the same plane as the fifth axis J5.
It is constituted by a nozzle 7 which is an emission port of a laser beam formed concentrically with 0 to a workpiece. Then, the robot moves from the side of the mounting table 1 to the intersection a with the first axis J1.
The laser beam Bi1 incident on the first axis (the laser beam Bi2 concentric with the first axis J1 from the lower part of the mounting table 1 is Bi2) is reflected concentrically with the first axis J1 by the mirror m0, and is reflected on the first axis. It is guided to the intersection a1 between J1 and the fourth axis J4. The laser beam guided to the intersection a1 is reflected concentrically with the fourth axis J4 by the mirror m1, and
The laser beam is guided to the intersection a2 of the fourth axis J4 and the fifth axis J5 through a laser beam transmission path 8 provided therein. The laser beam guided to the intersection a2 is reflected concentrically with the fifth axis J5 by the mirror m2 incorporated inside the first hollow head 5, and formed on the same plane as the fifth axis J5.
At the intersection a3 with the axis J0 perpendicular to Intersection a3
Is focused by a parabolic mirror Pm incorporated in the second hollow head 6, and the axis J0
A laser beam B0 is emitted to the outside of the robot from a nozzle 7 coaxially mounted on the outer periphery of the robot. The inside of the first hollow head 5 and the second hollow head 6 has a structure through which a laser beam can pass.

FIG. 2 shows a mechanical simplification of the above structure. The mirror m0 has a reflecting surface including an intersection a0 with the first axis J1 and the reflecting surface is connected to the first axis J1 by the first axis J1. Attach to the mounting table 1 toward the intersection a1 of the four axes J4, and set the mirror m1
Is provided on the swivel column 2 such that the reflecting surface includes an intersection a1 between the first axis J1 and the fourth axis J4 and the reflecting surface is directed toward the intersection a2 between the fourth axis J4 and the fifth axis J5. It is attached to the mirror angle setting mechanism 10 via the mirror position setting mechanism 9.
A mirror angle setting mechanism 10 is incorporated in the mirror position setting mechanism 9, and the mirror m1 has a reflecting surface rotatably mounted around a sixth axis J6 provided in the mirror angle setting mechanism 10. The mirror position setting mechanism 9 is attached to an upright plate 11 erected on the turning column 2 on the back side of the first arm 3, and moves up and down along a seventh axis J7. The mirror m2 has a reflecting surface including an intersection a2 between the fourth axis J4 and the fifth axis J5, and the reflecting surface is perpendicular to a fifth axis formed on the same plane as the fifth axis J5 and the fifth axis. Intersection a3 with the main axis J0
The parabolic mirror Pm includes the intersection point a3 of the fifth axis J5 and the axis J0 on the reflecting surface, and the reflecting surface faces the axis J0. Attach so that the focus of the parabolic mirror Pm is on J0.

The mirror m1 has a mirror angle setting mechanism 10 for matching the normal passing through the intersection point a1 to a bisector n of the angle formed by the laser beam incident on the mirror m1 and the fourth axis J4. A mirror position setting mechanism 9 is provided to make the intersection a1 follow and match the amount of change on the axis of the laser beam incident on the mirror m1 with the change in the elevation angle of the arm 3 and the second arm 4. The mirror angle setting mechanism 10 and the mirror position setting mechanism 9 of the mirror m1 have the following configurations as shown in FIGS. FIG. 3 is a side view, and FIG. 4 is a front view. A ball screw 9c is attached to the shaft end of a mirror position setting movement servomotor 9b incorporated in the frame 9a, and the mirror attachment frame 9d is rotated in parallel with the laser beam incident on the mirror m1 by rotating the ball screw 9c. Move on axis J7. The mirror position setting movement servo motor 9b includes a movement amount detector 9e, and controls the mirror position setting movement servo motor 9b by the normal servo control based on the detected movement amount of the mirror mounting frame 9d. The arm 4 is moved by a movement amount calculated from the elevation angle of the arm 4. The mirror mounting shaft 10a is attached to the mirror mounting frame 9d at the intersection a.
1 is rotatably held about a sixth axis J6 including the axis of rotation. The mirror m1 is fixed to the mirror mounting shaft 10a so as to rotate about the intersection a1 including the reflection surface and the sixth axis J6 as a rotation axis. The mirror m1 is driven to rotate by a mirror angle setting rotation servomotor 10b incorporated in the mirror mounting frame 9d via a mirror mounting shaft 10a mounted on the shaft end of the motor 10b. The mirror angle setting rotation servomotor 10b includes a mirror rotation angle detector 10c. Based on the detected angle of the mirror m1, a normal line passing through the intersection a1 on the reflection surface of the mirror m1 is applied to the mirror m1 by ordinary servo control. This is to match the angle bisector n of the angle formed by the incident laser beam and the fourth axis J4.

When the above configuration is simplified to a coordinate system, it becomes as shown in FIGS. FIG. 5 shows the mounting table 1 for the laser beam.
FIG. 6 shows a case where the light is incident from the upper part of the revolving column 2 concentrically with the first axis J1. As shown in the figure, a second axis J2 is provided at a position eccentric from the first axis J1 by a distance M, and the distance between the second axis J2 and the third axis J3, that is, the arm length of the first arm 3 is L. Then, when the first arm 3 is tilted by the angle α about the second axis J2 and the second arm 4 is tilted by the angle θ about the third axis J3, the mirror m1 needs to be moved to the position of m11. There is. The moving amount S at this time = (M + L sin α) tan
θ.

The robot has the first axis J1 and the second axis J1.
2, third axis J3, fourth axis J4, fifth axis J5, sixth axis J6
The CNC controller drives the respective servo motors for rotating the nozzles and the moving axis of the seventh axis J7, and aims the nozzle 7 at an arbitrary position in the three-dimensional space at an arbitrary angle, and at the position, a laser beam. The beam is emitted and laser processing is performed. That is, as shown in FIG. 7, the angle detection signals of the second axis J2 and the third axis J3 incorporated in the robot are input to the robot controller 21, and the above equation S = (M + L sin α) ) Calculates tan θ and controls the mirror drive controller 22 so that the bisector of the angle formed by the first axis J1 and the fourth axis J4 coincides with the normal passing through the intersection a1 of the mirror m1. I do.

Next, FIG. 8 and FIG. 9 show a comparison of the operation range of the robot. FIG. 8 is a mechanically simplified configuration of a mirror movable articulated laser machining robot according to the present invention, and FIG. 9 is a mechanically simplified configuration of a conventional mirror movable polar coordinate laser machining robot. Assuming that the maximum distance X from the axis of the first axis J1 is the same, the articulated laser machining robot having a mirror movable than the polar coordinate type laser machining robot having the movable Y and Z dimensions indicating the operation range 25 is a movable mirror. Is larger. The number of mirrors used at this time is the same.

[0019]

As described above, according to the present invention, it is possible to obtain an articulated laser machining robot in which the operating range of the robot is large and the number of mirrors is significantly reduced. Therefore, attenuation of the transmission energy of the laser beam by the mirror can be suppressed to a low level, and adjustment, maintenance, and inspection work on the mirror such as calibration and replacement of the mirror can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view perspectively showing an articulated laser machining robot according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a configuration of an embodiment.

FIG. 3 is a side view of a mirror angle setting mechanism and a mirror position setting mechanism in the embodiment.

FIG. 4 is a front view of FIG. 3;

5 is a schematic diagram showing a coordinate system of the robot of FIG. 1 when a laser beam is incident from below the robot.

FIG. 6 is a schematic diagram showing a coordinate system of the robot in FIG. 1 when a laser beam is incident from above the robot.

FIG. 7 is a control block diagram of the robot according to the embodiment.

FIG. 8 is a schematic diagram showing an operation range of the mirror movable articulated robot according to the embodiment.

FIG. 9 is a schematic diagram showing an operation range of a conventional mirror movable polar coordinate robot.

FIG. 10 is a schematic view of a conventional articulated laser machining robot.

FIG. 11 is a perspective view of a conventional mirror movable polar coordinate robot.

FIG. 12 is a schematic diagram of the configuration of FIG. 11;

FIG. 13 is a perspective view of a mirror angle setting mechanism in the robot of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Installation stand 2 Revolving column 3 1st arm 4 2nd arm 5 1st hollow head 6 2nd hollow head 7 Nozzle 8 Laser beam transmission path 9 Mirror position setting mechanism 10 Mirror angle setting mechanism 11 Standing plate m0, m1, m2 Mirror Pm parabolic mirror a0, a1, a2, a3 intersection point J1 first axis J2 second axis J3 third axis J4 fourth axis J5 fifth axis

Claims (4)

(57) [Claims] 1. A mounting table, a turning column mounted on the mounting table so as to be rotatable around a central axis perpendicular to the mounting table, and a first arm connected to the turning column so as to be able to descend. A second arm connected to the first arm so as to be able to descend, and an inside of the second arm concentric with an axis passing through the center of rotation of the second arm and forming the same plane as the center of rotation of the revolving column. The provided laser beam transmission path is disposed at the intersection of the rotation center axis of the turning column and the extension of the center of the laser beam transmission path, and reflects the laser beam incident concentrically with the rotation center axis of the turning column. An articulated laser machining robot comprising: a mirror for guiding the laser beam to the laser beam transmission path. 2. The mirror is rotated such that a bisector of an angle formed by a center axis of the laser beam transmission path and a rotation center axis of the swivel column coincides with a perpendicular line on the mirror reflecting surface. 2. The multi-joint laser processing robot according to claim 1, further comprising a mirror angle setting mechanism for following. 3. The minimum distance between the rotation center of the first arm and the rotation center axis of the swivel column is M, and the shortest straight line connecting the rotation center of the first arm and the rotation center of the second arm is M. The angle formed by the rotation center axis of the column is α, the shortest linear distance between the rotation center of the first arm and the rotation center of the second arm is L, the rotation center axis of the turning column and the laser beam transmission path. Flat formed by the central axis of
On a plane perpendicular to the rotation center axis and the center axis.
When the formed angle is θ, the rotation center position of the mirror on the rotation center axis of the swivel column when α = 0 ° and θ = 0 ° is “0”, and the angles α and θ change. When the amount of change of the rotation center position of the mirror from “0” at that time is S, the mirror sets the rotation center position of the mirror so as to match the change amount obtained by S = (M + L sin α) tan θ. 3. The multi-joint type laser machining robot according to claim 1, further comprising a mirror position setting mechanism for moving and following. 4. The second arm includes a hollow head having at least two axes orthogonal to each other, one of which is coincident with the center axis of the laser beam transmission path, and is rotatable around the axis. 2. The articulated laser machining robot according to claim 1, wherein a second mirror is disposed at an intersection of the axes.