JP4899099B2 - Work robot position measurement device - Google Patents

Description

  The present invention relates to an apparatus for measuring a position on a workpiece to be a target of a work robot.

(Prior art 1)
Conventionally, in order to measure a three-dimensional position of an object such as a workpiece to be worked, a light cutting method is generally used.

The principle of the light cutting method will be described with reference to FIG.

That is, the slit light 60 is obliquely projected onto the workpiece W, and the image 70 including the light section image 70 </ b> A corresponding to the slit light 60 is captured by the camera 50. The light section image 70 </ b> A includes characteristic points on the image 70, for example, change points P on the surface of the workpiece W. Therefore, by calculating the coordinate position of the feature point P on the image 70, the two-dimensional coordinate position of the workpiece W on the XZ plane can be obtained. Further, the slit light perpendicularly intersecting with the slit light 60 shown in FIG. 1 is projected onto the work W, and similarly, the coordinate position of the work W in the Y-axis direction is obtained. As described above, the three-dimensional coordinate position of the workpiece W is obtained.

(Prior art 2)
Also in the field of work robots such as welding robots, as seen in Patent Document 1, for example, attempts have been made to measure the three-dimensional coordinate position of the work W to be worked using the optical cutting method.

  The operation when the optical cutting method is applied to the welding robot will be described with reference to FIG.

FIG. 4A shows a configuration in which a welding torch 20 that is a working tool is provided on the wrist tip shaft 11 of the welding robot 10 and a position measuring unit 30 that performs position measurement by an optical cutting method is provided. Yes.

  In the position measurement unit 30, a slit light source 40 that projects the slit light 60 toward the work W to be worked, and a camera 50 that captures an image including a light cut image corresponding to the slit light 60 are provided. .

  As shown in FIG. 4B, when welding the member WA and the member WB, in order to measure the three-dimensional position of the groove (weld line) of the workpiece W composed of the member WA and the member WB, 4 (b) and FIG. 4 (c), the wrist tip shaft 11 of the welding robot 10 is rotated, and slit light 61 and 62 that intersect perpendicularly are sequentially projected from the slit light source 40 onto the workpiece W. To do. Next, an image including a light cut image corresponding to the slit light 61 and an image including a light cut image corresponding to the slit light 61 are sequentially acquired by the camera 50, and based on the acquired image, the workpiece W is obtained. The three-dimensional position of the groove is measured.

  As described above, in the prior art, in order to measure the three-dimensional coordinate position of the workpiece W to be worked using the optical cutting method, it is necessary to rotate the wrist tip shaft 11 of the welding robot 10 for the measurement. was there.

(Prior art 3)
Patent Document 2 is an invention related to the general technical field of position measurement, in which two slit lights intersecting at right angles toward an object are simultaneously projected from two slit light sources to determine the three-dimensional position of the object. The invention of measuring is described.

(Prior art 4)
Patent Document 3 describes an invention in which an imaging device is provided on a wrist tip axis of a welding robot, a welding torch and a workpiece are imaged by the imaging device, and a teaching point is corrected from a result of image processing of the captured image. Yes. The invention described in Patent Document 3 solves the problem of preventing the imaging device provided on the wrist tip shaft of the welding robot from interfering with the workpiece when the program is played back when the welding robot program is created offline. Is described. In order to achieve this solution, Patent Document 3 describes an invention in which an adapter is provided on the wrist tip shaft of a welding robot and the distance between the imaging device and the welding torch is increased by the adapter.
JP 2006-200909 A JP-A-6-109442 JP 2005-131761 A

  According to the invention described in Patent Document 1, it is necessary to rotate the wrist tip axis of the welding robot in order to measure the three-dimensional position by the optical cutting method in the welding robot. For this reason, in addition to the operation of the drive shaft of the welding robot associated with the original welding operation, the drive shaft of the welding robot must be operated only for position measurement, which requires time for the work and the work efficiency is deteriorated. There's a problem.

Moreover, by rotating the wrist tip axis of the welding robot during position measurement, the position measuring unit 30 provided on the wrist tip axis may interfere with the workpiece W and various devices.

The present invention has been made in view of such circumstances, and when performing three-dimensional position measurement by a light cutting method in a work robot, the operation efficiency of the drive axis of the work robot is eliminated, thereby improving work efficiency. An object of the present invention is to avoid the position measuring unit from interfering with a workpiece or the like.

  Here, in Patent Document 2, since two slit lights are simultaneously projected onto the workpiece, an image including two light cut images corresponding to the two slit lights is acquired. Therefore, when an image is processed, a process of identifying two light cut images is added, which causes a problem that the image processing becomes complicated. For this reason, there is a possibility that a feature point on the image is erroneously recognized. Therefore, the technique of simultaneously projecting two slit lights onto the work cannot be employed.

  Moreover, the invention described in Patent Document 2 is an invention belonging to the general technical field of position measurement, and does not disclose any configuration in which a position measurement unit is provided on the wrist tip axis of the work robot. That is, Patent Document 2 does not suggest the problem of the present invention to solve various problems that occur by turning the position measuring unit of the wrist tip axis of the work robot.

  The invention described in Patent Document 3 is an invention in which an imaging device is provided on the wrist axis of the welding robot, the welding torch and the workpiece are imaged by the imaging device, and the teaching point is corrected from the result of image processing of the captured image. Thus, it is not an invention of performing position measurement by the light cutting method as in the present invention. Therefore, the present invention is configured to rotate the position measuring unit of the wrist tip axis of the work robot to obtain the intersecting slit light, and to solve various problems caused by turning the position measuring unit of the wrist tip axis of the work robot. This issue is not suggested in the first place.

The first invention is
A work tool is provided on the wrist tip axis of the work robot, and a position measurement unit that performs position measurement by an optical cutting method is provided.
In the position measurement unit, a first slit light source, a second slit light source, and a first slit light source that project the first slit light and the second slit light that cross each other on the work target. An image pickup means for picking up a first image including a light cut image corresponding to the slit light and a second image including a light cut image corresponding to the second slit light;
Projecting the first slit light to the work by the first slit light source, and projecting the second slit light to the work by the second slit light source in sequence,
A first image and a second image are sequentially acquired by the imaging means,
Measuring the three-dimensional position of the workpiece based on the acquired first image and second image;
It is a position measuring device for a work robot.

The second invention is
A work tool is provided on the wrist tip axis of the work robot, and a position measurement unit that performs position measurement by an optical cutting method is provided.
Rotation that rotates the slit light source so as to obtain a slit light source that projects slit light toward the work to be worked and a first slit light and a second slit light that intersect on the work in the position measurement unit A mechanism and an imaging unit that captures a first image including a light-cut image corresponding to the first slit light and also captures a second image including a light-cut image corresponding to the second slit light are provided. And
By operating the rotation mechanism, the slit light source sequentially projects the first slit light onto the workpiece, and the slit light source projects the second slit light onto the workpiece.
A first image and a second image are sequentially acquired by the imaging means,
Measuring the three-dimensional position of the workpiece based on the acquired first image and second image;
It is a position measuring device for a work robot.

The third invention is the first invention or the second invention,
When teaching the operation program of the work robot, measure the three-dimensional position of the reference point on the master workpiece,
When replaying the operation program of the work robot, measure the 3D position of the reference point on the workpiece,
Calculating a positional deviation between the three-dimensional position of the reference point measured for the workpiece and the three-dimensional position of the reference point measured for the master workpiece;
The teaching point position described in the operation program is corrected based on the calculated positional deviation.

4th invention is 1st invention or 2nd invention,
At the time of teaching to teach the operation program of the work robot, the three-dimensional positions of a plurality of reference points on the master work corresponding to the plurality of teaching points described in the operation program are measured,
When reproducing the operation program of the work robot, the three-dimensional positions of a plurality of reference points on the workpiece corresponding to the plurality of teaching points described in the operation program are measured,
Calculating a positional deviation between the three-dimensional positions of the plurality of reference points measured for the workpiece and the three-dimensional positions of the plurality of reference points measured for the master workpiece;
Based on the calculated displacement, the positions of a plurality of teaching points described in the operation program are corrected.

A fifth invention is the fourth invention,
The three-dimensional position of the reference point corresponding to the teaching point is measured when the operation program of the work robot is reproduced.

In the first invention, as shown in FIG. 5, the wrist tip shaft 11 of the work robot 10 is provided with a work tool 20 and a position measurement unit 30 that performs position measurement by an optical cutting method.

  In the position measurement unit 30, a first slit light source 41 that projects the first slit light 61 and the second slit light 62 intersecting on the work W to be worked toward the work (not shown). The second slit light source 42 and the first image 71 (see FIGS. 8A and 8C) including the light section image 70A corresponding to the first slit light 61 are imaged, and the second slit An imaging unit 50 that captures a second image 72 (see FIGS. 8B and 8D) including a light section image 70B corresponding to the light 62 is provided.

  The first slit light source 41 projects the first slit light 61 onto the workpiece W, and the second slit light source 42 projects the second slit light 62 onto the workpiece W sequentially.

  Then, as illustrated in FIGS. 7A and 7B, the first image 71 and the second image 72 are sequentially acquired by the imaging unit 50.

  Then, based on the acquired first image 71 and second image 72, the three-dimensional position P (X, Y, Z) of the workpiece W is measured.

In the second invention, as shown in FIG. 6A, the wrist tip shaft 11 of the work robot 10 is provided with a work tool 20 and a position measurement unit 30 for measuring the position by the light cutting method. ing.

  As shown in FIGS. 6B and 6C, the position measurement unit 30 intersects with the slit light source 40 that projects the slit lights 61 and 62 toward the work W to be worked on the work W. A rotation mechanism 45 that rotates the slit light source 40 so that the first slit light 61 and the second slit light 62 are obtained, and a first image 71 that includes a light cut image 70A corresponding to the first slit light 61. An image pickup means 50 is provided that picks up an image and picks up a second image 72 including a light section image 70 </ b> B corresponding to the second slit light 62.

  As shown in FIGS. 6B and 6C, by operating the rotation mechanism 45, the slit light source 40 projects the first slit light 61 onto the workpiece W, and the slit light source 40 emits the second slit light. The light is sequentially projected onto 62 workpieces W.

  As shown in FIGS. 7A and 7B, the first image 71 and the second image 72 are sequentially acquired by the imaging unit 50. Based on the acquired first image 71 and second image 72, the three-dimensional position P (X, Y, Z) of the workpiece W is measured.

In the third invention, as shown in FIGS. 8A and 8B, at the time of teaching to teach the operation program of the work robot 10, the three-dimensional position (Xm, Ym, Zm) of the reference point Pm on the master work Wm. Is measured (steps 103 and 105 in FIG. 9).

  Then, as shown in FIGS. 8C and 8D, at the time of reproduction for reproducing the operation program of the work robot 10, the three-dimensional position (Xp, Yp, Zp) of the reference point Pp on the workpiece Wp is measured. (Steps 203 and 205 in FIG. 10).

Then, the positional deviation between the three-dimensional position (Xp, Yp, Zp) of the reference point Pp measured for the workpiece Wp and the three-dimensional position (Xm, Ym, Zm) of the reference point Pm measured for the master workpiece Wm. ΔX (= Xp−Xm), ΔY (= Yp−Ym), and ΔZ (= Zp−Zm) are calculated (step 206 in FIG. 10).
Based on the calculated positional deviations ΔX (= Xp−Xm), ΔY (= Yp−Ym), and ΔZ (= Zp−Zm), the position of the teaching point described in the operation program is corrected (FIG. 10 step 207).

In the fourth invention, as shown in FIG. 9, at the time of teaching to teach the operation program of the work robot 10, a plurality of reference points on the master work Wm corresponding to the plurality of teaching points PC and PD to be described in the operation program. The three-dimensional positions (XmC, YmC, ZmC) and (XmD, YmD, ZmD) of PmC and PmD are measured (steps 103, 105, and 107).

  As shown in FIG. 10, at the time of reproduction for reproducing the operation program of the work robot 10, 3 of the plurality of reference points PpC and PpD on the workpiece Wp corresponding to the plurality of teaching points PC and PD described in the operation program. The dimension positions XpC, YpC, ZpC) and (XpD, YpD, ZpD) are measured (steps 203, 205, 208).

A plurality of reference points PpC, PpD measured for the workpiece Wp, a three-dimensional position XpC, YpC, ZpC), (XpD, YpD, ZpD), and a plurality of reference points measured for the master workpiece Wm. The positional deviations ΔXC, ΔYC, ΔZC and ΔXD, ΔYD, ΔZD with respect to the three-dimensional positions (XmC, YmC, ZmC) and (XmD, YmD, ZmD) of PmC, PmD are calculated (steps 206, 208 in FIG. 10). .
Based on the calculated positional deviations ΔXC, ΔYC, ΔZC and ΔXD, ΔYD, ΔZD, the positions of the teaching points PC, PD described in the operation program are corrected (steps 207, 208 in FIG. 10).

As described above, according to the present invention, the first slit light intersecting on the work W from the position measurement unit 30 toward the work W to be worked while the wrist tip shaft 11 of the work robot 10 is fixed. 61, since the second slit light 62 can be projected, it is not necessary to operate the drive shaft of the work robot 10 when performing three-dimensional position measurement by the light cutting method. Therefore, in addition to the operation of the drive shaft of the work robot 10 associated with the original work (for example, welding work), there is no loss of time for operating the drive shaft of the work robot 10 only for position measurement, and the work can be performed in a short time Immediate work efficiency can be improved.

Moreover, since it is not necessary to rotate the wrist tip shaft 11 of the work robot 10 at the time of position measurement, the position measurement unit 30 provided on the wrist tip shaft 11 does not interfere with the workpiece W or various devices at the time of position measurement. .

In particular, in the fourth invention, it is not necessary to operate the drive shaft of the work robot 10 only for position measurement at the plurality of teaching points PC and PD at the time of teaching and reproducing the operation program of the work robot 10. Further, the time loss can be further reduced and the working efficiency can be further improved.

  By welding the workpieces, thermal distortion may occur in the workpiece that is a welded structure, which may cause displacement. In this case, it is desirable to correct the misalignment by measuring the position during welding.

In the fifth invention, when the operation program of the work robot 10 is reproduced, the three-dimensional position of the reference point PpD corresponding to the teaching point PD is measured, and the displacement of the teaching point PD is corrected during work (during welding) ( Steps 208 'and 209' in FIG. As described above, according to the present invention, in the middle of the welding operation, the positional shift caused by the thermal strain is corrected in a timely manner, so even if a positional shift occurs in the workpiece during production due to the influence of the thermal strain, The tool tip can be moved precisely along the weld line.
Further, if the robot driving shaft (wrist tip shaft) is operated only for measuring the position during welding by applying the conventional technique, the operation of the original operation program is affected. Further, since the operation robot is operated only for position measurement and then the operation tool tip is moved to the original teaching point, a time loss is large. According to the present invention, since it is not necessary to operate the wrist tip axis of the work robot when performing position measurement during welding, there is little influence on the operation of the work program, and time loss can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the embodiment, a welding robot 10 that performs welding work such as arc welding work is assumed as the work robot.

FIG. 14 shows an overall configuration of a welding system including the welding robot of the embodiment.

As shown in FIG. 14, the welding system includes a welding robot 10, an image processing device 80, and a robot controller 90.

The welding robot 10 of the embodiment is, for example, a 6-axis articulated robot having axes 11, 12, 13, 14, 15, and 16, and includes a drive unit 19. The drive unit 19 includes a servo amplifier and a robot motor. The drive part 19 drives each axis | shaft 11, 12, 13, 14, 15, 16 according to a drive command.

FIG. 15A shows an enlarged arm tip portion of the welding robot 10.

The welding robot 10 has an arm 10a, and a wrist tip shaft 11 is provided at the tip of the arm 10a. A welding torch 20 and a position measuring unit 30 are attached to the wrist tip shaft 11 via a bracket 17. The wrist tip shaft 11 is a drive shaft that relatively rotates the bracket 17 and the welding torch 20 and the position measurement unit 30 attached thereto with respect to the arm 10a.

By driving each axis 11, 12, 13, 14, 15, 16 on the robot coordinate system XYZ, the coordinate position P (X, Y,. Z) and torch attitude angles (A, B, C) are changed. Thereby, the welding torch 20 can be moved along the weld line of the base material in a desired posture. Note that the torch posture angles (A, B, C) are defined by Euler angles.

In response to the rotation of the wrist tip shaft 11, the bracket 17, the welding torch 20 attached thereto, and the position measurement unit 30 rotate relative to the arm 10a.

The position measurement unit 30 of the welding robot 10 and the image processing device 80 are connected by a camera cable 81.

The image processing apparatus 80 and the robot controller 90 are connected by a communication cable 82.

The robot controller 90 and the drive unit 19 of the welding robot 10 are connected by a drive signal line 83.

The position measurement unit 30 is configured to include a camera 50 as an imaging unit as will be described later.

An image signal indicating an image captured by the camera 50 is sent to the image processing device 80 via the camera cable 81.

In the image processing apparatus 80, the image sent from the camera 50 of the position measurement unit 30 is subjected to image processing to detect characteristic points on the image.

Data indicating feature points on the image processed by the image processing apparatus 80 is sent to the robot controller 90 via the communication cable 82. The robot controller 90 also sends a start command signal for instructing the start of image processing and control parameters necessary for image processing to the image processing device 80 via the communication cable 82.

The robot controller 90 is configured to include various substrates, CPU, memory, and the like as hardware necessary for controlling the welding robot 10. The robot controller 90 stores software necessary for various controls such as an operation program for operating the welding robot 10. As will be described later, the robot controller 90 corrects the three-dimensional position of the teaching point described in the operation program based on the data indicating the feature point on the image sent from the image processing device 80.

The robot controller 90 generates a drive command for driving each axis of the welding robot 10 according to the operation program. The generated drive command is sent to the drive unit 19 of the welding robot 10 via the drive signal line 83.

The axes 11 to 16 of the welding robot 10 are driven in accordance with a drive command sent from the robot controller 90. Thereby, the welding robot 10 operates according to the operation program.

FIG. 15 is a perspective view showing an example in which the position measuring unit 30 is attached to the welding robot 10.

FIG. 15A shows a mounting example in which the position measurement unit 30 is attached to the bracket 17. A position measuring unit 30 is arranged near the wrist tip shaft 11 and at a position away from the tip of the welding torch 20.

FIG. 15B shows a mounting example in which the position measurement unit 30 is attached to the welding torch 20. A position measurement unit 30 is disposed at a position away from the wrist tip shaft 11 and close to the tip of the welding torch 20.

The mounting position of the position measurement unit 30 is determined at an appropriate position according to the size and shape of the position measurement unit 30, the focal length of the built-in camera 50, and the like.

In the case of the mounting example of FIG. 15A, there is an advantage that welding fume can be avoided because the position measurement unit 30 is away from the work W to be worked.

In the following description, it is assumed that the position measurement unit 30 is attached to the welding robot 10 in the attachment example shown in FIG.

FIG. 5 shows a first configuration example of the position measurement unit 30.

As shown in FIG. 5, the wrist tip shaft 11 of the welding robot 10 is provided with a welding torch 20 as a working tool via a bracket 17 and a position measuring unit 30.

The position measurement unit 30 is a housing with a built-in device that performs position measurement by a light cutting method.

  The light cutting method will be described with reference to FIGS. 1, 2, and 3. 1 (a), 2 (a), and 3 (a) are views of the workpiece W and the camera 50 as viewed from the front. FIGS. 1 (b), 2 (b), and 3 (b) FIGS. 1C, 2 </ b> C, and 3 </ b> C show an image 70 captured by the camera 50 as viewed from the side of the workpiece W and the camera 50.

  The camera 50 includes a lens 51 and a filter 52. The filter 52 transmits only light having the same wavelength as the laser light. By scanning the laser beam or passing the laser beam through the cylindrical lens, the slit beam 60 having a certain spread width in a predetermined direction is formed. The slit light 60 is emitted from a slit light source not shown in FIGS.

As shown in FIG. 1, the slit light 60 is obliquely projected onto the work W, and an image 70 including a light section image 70 </ b> A corresponding to the slit light 60 is captured by the camera 50. The light section image 70 </ b> A includes feature points on the image 70, for example, change points P on the surface of the workpiece W. Therefore, by calculating the coordinate position of the feature point P on the image 70, the two-dimensional coordinate position of the workpiece W on the XZ plane can be obtained. Further, slit light (not shown) perpendicular to the slit light 60 shown in FIG. 1 is projected onto the workpiece W, and the coordinate position of the workpiece W in the Y-axis direction is similarly obtained. As described above, the three-dimensional coordinate position serving as a reference for the feature point of the workpiece W is obtained.

  As shown in FIG. 2, when the workpiece W is shifted in the vertical direction, that is, in the Z-axis direction, the feature point P on the image 70 is shifted in the same vertical direction on the image 70.

  As shown in FIG. 3, when the work W is shifted in the left-right direction, that is, in the X-axis direction, the feature point P on the image 70 is shifted in the same left-right direction on the image 70.

As shown in FIG. 5, in the position measurement unit 30, the first slit light 61 and the second slit light that intersect perpendicularly on the work W to be worked in order to perform position measurement by the above-described optical cutting method. The first slit light source 41 and the second slit light source 42 that project the light 62 toward the workpiece W, respectively, and the first image 71 including the light cut image 70A corresponding to the first slit light 61 are captured. A camera 50 is provided as an imaging unit that captures the second image 72 including the light section image 70 </ b> B corresponding to the second slit light 62.

The first slit light source 41 and the second slit light source 42, for example, emit HeNe (helium neon) laser light as slit light through a cylindrical lens. Moreover, you may form slit light by scanning a laser beam. Note that the slit light is not necessarily laser light.

In FIG. 5, a mirror 43 that reflects the laser light emitted from the first slit light source 41 or the second slit light source 42 is provided in order to reduce the size of the housing of the position measurement unit 30 as much as possible. ing. However, implementation without the mirror 43 is also possible.

As the camera 50, for example, a CCD camera or a CMOS camera is used. The camera 50 is provided with a lens 51 and a filter 52. The filter 52 transmits only light having the same wavelength as the laser light.

In FIG. 5, for convenience of explanation, the first slit light 61 and the second slit light 62 are shown together in the same figure, but in the control of this embodiment, the first slit light is described later. The first slit light 61 is projected onto the workpiece W by the light source 41, and the second slit light 62 is projected onto the workpiece W sequentially from the second slit light source 42. That is, when one slit light source is turned on, the other slit light source is turned off.

FIG. 6 shows a second configuration example of the position measurement unit 30.

As shown in FIG. 6A, the wrist tip shaft 11 of the welding robot 10 is provided with a welding torch 20 as a working tool via a bracket 17 as in the configuration of FIG. A unit 30 is provided.

The position measurement unit 30 is a housing with a built-in device that performs position measurement by a light cutting method.

  As shown in FIGS. 6B and 6C, in the position measurement unit 30, a slit light source 40 that projects slit light 61 and 62 toward the work W to be worked, and a vertical position on the work W. A first image including a rotation mechanism 45 that rotates the slit light source 40 so as to obtain the intersecting first slit light 61 and second slit light 62, and a light cut image 70 </ b> A corresponding to the first slit light 61. A camera 50 is provided as an imaging unit that captures the second image 72 including the light section image 70 </ b> B corresponding to the second slit light 62. By positioning the rotation position of the rotation mechanism 45 at the first position, the first slit light 61 is projected, and by positioning the rotation position of the rotation mechanism 45 at the second position, the second slit light is emitted. 62 is projected.

  As shown in FIG. 6D, the rotation mechanism 45 includes, for example, a motor 46 and a transmission mechanism 47 that transmits the rotation of the output shaft of the motor 46 to the slit light source 40 to rotate the slit light source 40. If the motor 46 can rotate the slit light source 40 90 degrees and position it at that angle in order to form the first slit light 61 and the second slit light 62 that intersect perpendicularly on the workpiece W, Any type of motor such as a servo motor or a stepping motor can be used. An actuator other than a motor, such as a rotary air cylinder, may be used.

  As shown in FIGS. 6B and 6C, by operating the rotation mechanism 45, the slit light source 40 projects the first slit light 61 onto the workpiece W, and the slit light source 40 emits the second slit light. The light projecting to the work W 62 is sequentially performed. That is, when one slit light source is turned on, the other slit light source is turned off.

  Image processing performed in the image processing apparatus 80 will be described with reference to FIG.

That is, when the original image 70 captured by the camera 50 is captured by the image processing device 80 (FIG. 13A), the original image 70 is binarized and a light section image 70A corresponding to the slit light 61 is obtained. Clearly distinguished from the background. Since the original image is blurred or noisy, noise is removed and the outline is clarified by setting a threshold value, etc., and the light section image 70A on the original image is digitized. (FIG. 13B). Next, the digitized information is arithmetically processed to extract feature points P of the figure of the light section image 70A, that is, break points (FIG. 13C).

(First example of position measurement)
Next, a first example of position measurement using the configuration of the above-described embodiment will be described.

  FIG. 16 is a perspective view showing a state in which the three-dimensional position of a groove (weld line) of the workpiece W composed of the member WA and the member WB is measured when the member WA and the member WB are welded.

First, as shown in FIG. 16A, the wrist tip shaft 11 of the work robot 10 is fixed at a predetermined position, the first slit light source 41 in the position measurement unit 30 is turned on, and the first slit light 61 is turned on. (The first configuration example), or the rotation mechanism 45 is positioned at a rotation position (first position) where the first slit light 61 can be emitted, and the first slit light 61 is emitted from the slit light source 40. (Second configuration example). Thus, the first slit light 61 whose X axis direction is the longitudinal direction is projected onto the workpiece W. Next, as shown in FIG. 7A, a first image 71 including a light section image 70 </ b> A corresponding to the first slit light 61 is acquired by the camera 50.

By performing image processing on the first image 71, the X coordinate position and the Z coordinate position (X, Z) of the feature point P that is a representative point on the image 71 are obtained. By converting the coordinate positions X and Z of the feature point P (X, Z) on the image 71 into the coordinate position of the robot coordinate system, the X coordinate position and the Z coordinate position of the reference point on the workpiece W are obtained. In the following description, for convenience of explanation, the coordinate position on the image is assumed to be the coordinate position on the robot coordinate axis.

Next, as shown in FIG. 16B, the wrist slit shaft 11 of the work robot 10 is kept fixed, the first slit light source 41 in the position measurement unit 30 is turned off, and the second slit light source 42 is turned on. The second slit light 62 is turned on to emit light (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (second position) where the second slit light 62 can be emitted from the slit light source 40. The second slit light 62 is emitted. In this way, the second slit light 62 having the Y-axis direction as the longitudinal direction is projected onto the workpiece W. Next, as illustrated in FIG. 7B, the camera 50 acquires a second image 72 including a light section image 70 </ b> B corresponding to the second slit light 62.

By performing image processing on the second image 72, the Y coordinate position (Y) of the feature point P as a representative point on the image 72 is obtained. By converting the coordinate position Y of the feature point P (Y) on the image 72 into the coordinate position of the robot coordinate system, the Y coordinate position of the reference point on the workpiece W is obtained.

As described above, the three-dimensional position P (X, Y, Z) of the groove of the workpiece W is measured.

Next, the target position of the tip of the welding tool 20 is corrected based on the measured reference position P (X, Y, Z). Thereby, the welding robot 10 can be moved along a welding line with high precision.

(Second example of position measurement)
In the second example of the position measurement, the position of the teaching point described in the operation program is corrected based on the three-dimensional position of the reference point on the workpiece W obtained by the light cutting method.

That is, first, at the time of teaching for teaching the operation program of the work robot 10, the master work Wm is installed, and the position measurement unit 30 of the welding robot 10 is operated in the same manner as in FIG. As shown in FIGS. 7A and 7B, the three-dimensional position (Xm, Ym, Zm) of the reference point Pm on the master work Wm is measured in the same manner as in FIGS.

  Next, at the time of reproduction to reproduce the operation program of the work robot 10, the position measuring unit 30 of the welding robot 10 is operated in the same manner as in FIG. As shown in d), the three-dimensional position (Xp, Yp, Zp) of the reference point Pp on the workpiece Wp at the time of production is measured in the same manner as in FIGS. 7 (a) and 7 (b).

Next, the three-dimensional position (Xp, Yp, Zp) of the reference point Pp measured for the workpiece Wp during production, and the three-dimensional position (Xm, Ym, Zm) of the reference point Pm measured for the master workpiece Wm. Displacements ΔX (= Xp−Xm), ΔY (= Yp−Ym), and ΔZ (= Zp−Zm) are calculated.
The calculated positional deviations ΔX (= Xp−Xm), ΔY (= Yp−Ym), ΔZ (= Zp−Zm) are the teaching points P1, P2, P3. It can be regarded as a positional deviation of each tool tip target position P1, P2, P3... Of the groove (welding line) of the workpiece Wp.

  Therefore, the coordinate positions of the teaching points P1, P2, P3,... Are shifted by the displacements ΔX (= Xp−Xm), ΔY (= Yp−Ym), and ΔZ (= Zp−Zm) calculated as described above. Then, the three-dimensional position of each teaching point P1, P2, P3... Described in the operation program is corrected. Thereby, the front-end | tip of the welding torch 20 of the welding robot 10 can be moved along the groove | channel (welding line) of the workpiece | work W with high precision.

(Third example of position measurement)
In the second example of the position measurement described above, the positional deviations ΔX (= Xp−Xm), ΔY (= Yp−Ym), ΔZ (= Zp−Zm) calculated by the light cutting method are described in the operation program. The positions of the teaching points P1, P2, P3,... Are corrected by regarding the displacement of the teaching points P1, P2, P3,.

  However, the amount of displacement differs between the different positions of the workpiece when the master workpiece Wm is installed (when the operation program is taught) and when the workpiece Wp is installed during production (when the operation program is played back). There is. Accordingly, in such a case, it is desirable to obtain a positional deviation by a light cutting method for a plurality of reference points corresponding to different teaching points of the workpiece, and to correct the positional deviation individually for each teaching point.

  Hereinafter, an embodiment will be described in which a positional deviation is obtained by a light cutting method for a plurality of reference points corresponding to different teaching points of the workpiece, and the positional deviation is individually corrected for each teaching point.

FIG. 11 is a perspective view showing a state in which the three-dimensional position of the joint (weld line) of the workpiece W composed of the member WA and the member WB is measured when the member WA and the member WB are welded.

  As shown in FIG. 11A, it is assumed that fillet welding is performed by moving the tip of the welding torch 20 along the weld line from the welding start point PC to the welding end point PD.

  Hereinafter, description will be made with reference to the flowcharts shown in FIGS.

・ Operation at the time of teaching At the time of teaching to teach the operation program of the robot 10, the first slit light 61 crossing each other on the master work Wm, as shown in FIGS. 11 (b), 11 (c) and 11 (d), By sequentially projecting the slit light 62 of 2 and performing image processing in the same manner as in FIGS. 8A and 8B, a plurality of teaching points PC to be described in the operation program on the master work Wm, Three-dimensional positions (XmC, YmC, ZmC) and (XmD, YmD, ZmD) of a plurality of reference points PmC, PmD on the master work Wm corresponding to PD are measured.

That is, as shown in FIG. 11B, the welding robot 10 reaches a position where the position can be detected by the position measurement unit 30, that is, a position where an image of slit light on the master work Wm can be acquired by the camera 50. Is brought closer to the master work Wm. The welding robot 10 can project slit light on the teaching point PC (welding start point) side and moves to a position where the slit light on the teaching point PC (welding start point) side can be imaged (step 101 in FIG. 9).

Next, as shown in FIG. 11 (c), the wrist tip shaft 11 of the welding robot 10 is fixed at a predetermined position, the first slit light source 41 in the position measuring unit 30 is turned on, and the first slit light is turned on. 61 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (first position) where the first slit light 61 can be emitted, and the first slit light 61 is emitted (second second). Configuration example). In this way, the first slit light 61 whose X axis direction is the longitudinal direction is projected to the teaching point PC side of the master work Wm (step 102).
Next, as in FIG. 8A, the camera 50 acquires a first image 71 including a light section image 70 </ b> A corresponding to the first slit light 61.

By processing the first image 71, the X coordinate position and Z coordinate position (XmC, ZmC) of the feature point on the image corresponding to the teaching point PC (welding start point) to be described in the operation program are measured. Is done. By converting the coordinate positions XmC and ZmC of the feature points (XmC and ZmC) on the image 71 into the coordinate positions of the robot coordinate system, the X coordinate position and the Z coordinate position of the reference point PmC on the master work Wm are obtained. . (Step 103).

Next, as shown in FIG. 11D, the wrist slit shaft 11 of the welding robot 10 is fixed, the first slit light source 41 in the position measurement unit 30 is turned off, and the second slit light source 42 is turned on. Either the second slit light 62 is emitted and the second slit light 62 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (second position) where the second slit light 62 can be emitted. Light 62 is emitted. Thus, the second slit light 62 having the Y-axis direction as the longitudinal direction is projected to the teaching point PC side of the master work Wm (step 104).

Next, as in FIG. 8B, the camera 50 acquires the second image 72 including the light section image 70 </ b> B corresponding to the second slit light 62.

By processing the second image 72, the Y coordinate position (YmC) of the feature point on the image corresponding to the teaching point PC (welding start point) to be described in the operation program is measured. By converting the coordinate position YmC of the feature point (YmC) on the image 72 to the coordinate position of the robot coordinate system, the Y coordinate position of the reference point PmC on the master work Wm is obtained. (Step 105).

As described above, the three-dimensional position (XmC, YmC, ZmC) of the reference point PmC on the master work Wm corresponding to the teaching point PC (welding start point) to be described in the operation program is measured and stored. (Step 106).

Next, it is determined whether or not the positions of the corresponding reference points have been measured for all the target points, that is, all the teaching points that require position measurement by the light cutting method (step 107).
When the position measurement of the corresponding reference point is not performed for all the teaching points that require position measurement by the light cutting method (determination NO in step 107), the process returns to step 101, and the teaching point for which position measurement has not been performed. The same processing is performed for.

That is, the welding robot 10 can project slit light toward the teaching point PD (welding end point) and moves to a position where the slit light on the teaching point PD (welding end point) can be imaged (step 101 in FIG. 9). .

Next, similarly to FIG. 11C, the wrist tip shaft 11 of the welding robot 10 is fixed at a predetermined position, the first slit light source 41 in the position measurement unit 30 is turned on, and the first slit light is emitted. 61 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (first position) where the first slit light 61 can be emitted, and the first slit light 61 is emitted (second second). Configuration example). In this way, the first slit light 61 whose X axis direction is the longitudinal direction is projected to the teaching point PD side of the master work Wm (step 102).
Next, as in FIG. 8A, the camera 50 acquires a first image 71 including a light section image 70 </ b> A corresponding to the first slit light 61.

By processing the first image 71, the X coordinate position and Z coordinate position (XmD, ZmD) of the feature point on the image corresponding to the teaching point PD (welding end point) to be described in the operation program are measured. Is done. By converting the coordinate positions XmD and ZmD of the feature points (XmD and ZmD) on the image 71 into the coordinate positions of the robot coordinate system, the X and Z coordinate positions of the reference point PmD on the master work Wm are obtained. . (Step 103).

Next, as in FIG. 11D, the wrist slit shaft 11 of the work robot 10 is fixed, the first slit light source 41 in the position measurement unit 30 is turned off, and the second slit light source 42 is turned off. Either the second slit light 62 is emitted and the second slit light 62 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (second position) where the second slit light 62 can be emitted. Light 62 is emitted. Thus, the second slit light 62 having the Y-axis direction as the longitudinal direction is projected to the teaching point PD side of the master work Wm (step 104).

Next, as in FIG. 8B, the camera 50 acquires the second image 72 including the light section image 70 </ b> B corresponding to the second slit light 62.

By processing the second image 72, the Y coordinate position (YmD) of the feature point on the image corresponding to the teaching point PD (welding end point) to be described in the operation program is measured. By converting the coordinate position YmD of the feature point (YmD) on the image 72 to the coordinate position of the robot coordinate system, the Y coordinate position of the reference point PmD on the master work Wm is obtained. (Step 105).

As described above, the three-dimensional position (XmD, YmD, ZmD) of the reference point PmD on the master work Wm corresponding to the teaching point PD (welding end point) to be described in the operation program is measured and stored. (Step 106).

Next, it is determined whether or not the positions of the corresponding reference points have been measured for all the target points, that is, all the teaching points that require position measurement by the light cutting method (step 107).
When the position of the corresponding reference point is measured for all teaching points that require position measurement by the optical cutting method, that is, the positions of the corresponding reference points PmC and PmD are measured for the welding start point PC and the welding end point PD. If so (YES at step 107), an operation program for teaching the welding robot 10 of the operation program in which the data of the coordinate positions of the teaching points PC and PD is described is performed (step 108). Thus, the processing at the time of teaching is finished.

・ Operation at the time of reproduction At the time of reproduction to reproduce the operation program of the robot 10, first slit lights 61 intersecting each other on the workpiece Wp at the time of production in the same manner as in FIGS. 11 (b), (c) and (d). By sequentially projecting the second slit light 62 and performing image processing in the same manner as in FIGS. 8C and 8D described above, a plurality of teachings described in the operation program on the workpiece Wp at the time of production is performed. Three-dimensional positions (XpC, YpC, ZpC) and (XpD, YpD, ZpD) of a plurality of reference points PpC, PpD on the production workpiece Wp corresponding to the points PC, PD are measured.

That is, similarly to FIG. 11B, the slit light can be projected to the teaching point PC (welding start point) side, and the slit light image on the teaching point PC (welding start point) side can be acquired. The welding robot 10 is brought close to the workpiece Wp during production (step 201 in FIG. 10).

Next, similarly to FIG. 11C, the wrist tip shaft 11 of the welding robot 10 is fixed at a predetermined position, the first slit light source 41 in the position measurement unit 30 is turned on, and the first slit light is emitted. 61 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (first position) where the first slit light 61 can be emitted, and the first slit light 61 is emitted (second second). Configuration example). Thus, the first slit light 61 having the X-axis direction as the longitudinal direction is projected to the teaching point PC side of the production work Wp (step 202).
Next, as in FIG. 8C, the camera 50 acquires a first image 71 including a light section image 70 </ b> A corresponding to the first slit light 61.

By processing the first image 71, the X coordinate position and the Z coordinate position (XpC, ZpC) of the feature point on the image corresponding to the teaching point PC (welding start point) described in the operation program are measured. The By converting the coordinate positions XpC and ZpC of the feature points (XpC and ZpC) on the image 71 into the coordinate positions of the robot coordinate system, the X coordinate position and the Z coordinate position of the reference point PpC on the production workpiece Wp are obtained. It is done. (Step 203).

Next, similarly to FIG. 11D, the wrist slit shaft 11 of the welding robot 10 is fixed, the first slit light source 41 in the position measurement unit 30 is turned off, and the second slit light source 42 is turned on. Either the second slit light 62 is emitted and the second slit light 62 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (second position) where the second slit light 62 can be emitted. Light 62 is emitted. Thus, the second slit light 62 having the longitudinal direction in the Y-axis direction is projected onto the teaching point PC side of the production workpiece Wp (step 204).

Next, as in FIG. 8D, the camera 50 acquires a second image 72 including a light section image 70 </ b> B corresponding to the second slit light 62.

By processing the image 72, the Y coordinate position (YpC) of the feature point on the image corresponding to the teaching point PC (welding start point) described in the operation program is measured. By converting the coordinate position YpC of the feature point (YpC) on the image 72 into the coordinate position of the robot coordinate system, the Y coordinate position of the reference point PpC on the production work Wp is obtained. (Step 205).

As described above, the three-dimensional position (XpC, YpC, ZpC) of the reference point PpC on the production workpiece Wp corresponding to the teaching point PC (welding start point) described in the operation program is measured.

Next, the three-dimensional position (XpC, YpC, ZpC) of the reference point PpC measured for the workpiece Wp at the time of production, and the three-dimensional position (XmC, YmC, ZmC) of the reference point PmC measured for the master workpiece Wm. Displacements ΔX (= XpC−XmC), ΔY (= YpC−YmC), and ΔZ (= ZpC−ZmC) are calculated (step 206).
The positional deviations ΔX (= XpC−XmC), ΔY (= YpC−YmC) and ΔZ (= ZpC−ZmC) calculated in this way are the teaching points (welding start points) PC described in the operation program, that is, the welding line. This can be regarded as a displacement of each tool tip target position on the welding start point side.

  Therefore, the coordinate position of the teaching point PC is shifted by the displacements ΔX (= XpC−XmC), ΔY (= YpC−YmC), ΔZ (= ZpC−ZmC) calculated as described above, and described in the operation program. The three-dimensional position of the taught point PC is corrected (step 207).

Next, it is determined whether or not the positions of the corresponding reference points have been measured for all the target points, that is, all the teaching points that require position measurement by the light cutting method (step 208).
If the position measurement of the corresponding reference point has not been performed for all the teaching points that require position measurement by the optical cutting method (determination NO in step 208), the process returns to step 201, and the teaching points for which position measurement has not been performed The same processing is performed for.

That is, in FIG. 11B, the welding robot 10 can project slit light on the teaching point PD (welding end point) side, and the slit light on the production workpiece Wp on the teaching point PD (welding end point) side. The production work Wp is approached to a position where an image can be acquired (step 201 in FIG. 10).

Next, similarly to FIG. 11C, the wrist tip shaft 11 of the welding robot 10 is fixed at a predetermined position, the first slit light source 41 in the position measurement unit 30 is turned on, and the first slit light is emitted. 61 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (first position) where the first slit light 61 can be emitted, and the first slit light 61 is emitted (second second). Configuration example). Thus, the first slit light 61 having the X-axis direction as the longitudinal direction is projected to the teaching point PD side of the production workpiece Wp (step 202).
Next, as in FIG. 8C, the camera 50 acquires a first image 71 including a light section image 70 </ b> A corresponding to the first slit light 61.

By processing the first image 71, the X coordinate position and Z coordinate position (XpD, ZpD) of the feature point on the image corresponding to the teaching point PD (welding end point) described in the operation program are measured. The By converting the coordinate positions XpD and ZpD of the feature points (XpD and ZpD) on the image 71 into the coordinate positions of the robot coordinate system, the X coordinate position and the Z coordinate position of the reference point PpD on the production workpiece Wp are obtained. It is done. (Step 203).

Next, similarly to FIG. 11D, the wrist slit shaft 11 of the welding robot 10 is fixed, the first slit light source 41 in the position measurement unit 30 is turned off, and the second slit light source 42 is turned on. Either the second slit light 62 is emitted and the second slit light 62 is emitted (first configuration example), or the rotation mechanism 45 is positioned at a rotation position (second position) where the second slit light 62 can be emitted. Light 62 is emitted. Thus, the second slit light 62 having the longitudinal direction in the Y-axis direction is projected to the teaching point PD side of the production workpiece Wp (step 204).

Next, as in FIG. 8D, the camera 50 acquires a second image 72 including a light section image 70 </ b> B corresponding to the second slit light 62.

By performing image processing on the second image 72, the Y coordinate position (YpD) of the feature point on the image corresponding to the teaching point PD (welding end point) described in the operation program is measured. By converting the coordinate position YpD of the feature point (YpD) on the image 72 to the coordinate position of the robot coordinate system, the Y coordinate position of the reference point PpD on the production work Wp is obtained. (Step 205).

As described above, the three-dimensional position (XpD, YpD, ZpD) of the reference point PpD on the production workpiece Wp corresponding to the teaching point PD (welding end point) described in the operation program is measured.

Next, the three-dimensional position (XpD, YpD, ZpD) of the reference point PpD measured for the workpiece Wp during production, and the three-dimensional position (XmD, YmD, ZmD) of the reference point PmD measured for the master workpiece Wm. Displacements ΔX (= XpD−XmD), ΔY (= YpD−YmD), and ΔZ (= ZpD−ZmD) are calculated (step 206).
The positional deviations ΔX (= XpD−XmD), ΔY (= YpD−YmD) and ΔZ (= ZpD−ZmD) calculated in this way are the teaching points (welding end points) PD described in the operation program, that is, the welding line. This can be regarded as a displacement of each tool tip target position on the welding end point side.

  Therefore, the coordinate position of the teaching point PD is shifted by the positional deviations ΔX (= XpD−XmD), ΔY (= YpD−YmD) and ΔZ (= ZpD−ZmD) calculated as described above, and described in the operation program. The three-dimensional position of the teaching point PD is corrected (step 207).

Next, it is determined whether or not the positions of the corresponding reference points have been measured for all the target points, that is, all the teaching points that require position measurement by the light cutting method (step 208).
When the position of the corresponding reference point is measured for all the teaching points that need to be measured by the optical cutting method, that is, when the position of the corresponding reference point is measured for the welding start point PC and the welding end point PD ( (Yes in step 208), the operation program in which the coordinate position data of the teaching points PC and PD is corrected is executed to drive each axis of the welding robot 10. As a result, a welding operation according to the operation program is performed (step 209). When the operation of the welding robot 10 according to the operation program is finished, the processing at the time of reproduction is finished.

In this embodiment, the coordinate position of the teaching point PC, which is the welding start point, is shifted by positional deviations ΔX (= XpC−XmC), ΔY (= YpC−YmC), ΔZ (= ZpC−ZmC). The dimension position is corrected. Therefore, when the tip of the welding torch 20 of the welding robot 10 moves on the welding start point side of the welding line, the welding robot 10 can be moved with high accuracy along the welding line of the workpiece W, while the teaching point PD that is the welding end point is detected. The coordinate positions are also shifted by positional deviations ΔX (= XpD−XmD), ΔY (= YpD−YmD), ΔZ (= ZpD−ZmD), and the three-dimensional position is corrected. For this reason, when the front-end | tip of the welding torch 20 of the welding robot 10 moves the welding end point side of a welding line, it can be moved with high precision along the welding line of the workpiece | work W. FIG.

Further, according to the present embodiment, when the position of a plurality of teaching points PC and PD is measured at the time of teaching or reproducing the operation program of the welding robot 10, the welding robot conventionally performed only for position measurement is performed. The operation of the ten drive shafts becomes unnecessary. In this way, useless operation of the drive shaft of the welding robot 10 is not required for a large number of points, so that time loss can be further reduced and work efficiency can be further improved.

(Fourth example of position measurement)
By welding the workpieces, thermal distortion may occur in the workpiece that is a welded structure, which may cause displacement. In this case, it is desirable to correct the misalignment by measuring the position during welding.

In this embodiment, when the operation program of the welding robot 10 is reproduced (during welding work), the three-dimensional position of the reference point PpD corresponding to the teaching point PD is measured, and the displacement of the teaching point PD is corrected during the welding work. Is done. The processing of this embodiment will be described with reference to the flowcharts shown in FIGS.

• During teaching, processing is executed in the same manner as in FIG. That is, at the time of teaching the operation program, as in the third example of the position measurement described above, the position measurement of the reference points PmC and PmD corresponding to the welding start point PC and the welding end point PD is performed, and the teaching point PC, The contents of the operation program in which PD is described are taught to welding robot 10.

At the time of reproduction of the operation program at the time of reproduction, as shown in FIG. 12, the same processing as described in FIG. 10 is performed from step 201 to step 207, and the coordinate position of the teaching point PC that is the welding start point is The positional deviations ΔX (= XpC−XmC), ΔY (= YpC−YmC), and ΔZ (= ZpC−ZmC) are shifted to correct the three-dimensional position of the teaching point PC described in the operation program (step 207). ).

Next, an operation program is executed, and welding is performed along the weld line from the welding start point PC by the welding robot 10 (step 208 ').

However, in the case of the present embodiment, unlike the processing shown in FIG. 10, each time the operation program is executed, the processing from step 201 to step 207 is repeated in the same way, and the position of the teaching point is changed during the welding operation. The deviation is corrected (steps 208 ′ and 209 ′).

That is, during the welding operation, positional deviations ΔX (= XpD−XmD), ΔY (= YpD−YmD), ΔZ (= ZpD−ZmD) are determined for the next teaching point, that is, the welding end point PD (step) 206) The coordinate position of the welding end point PD is shifted by this positional deviation, and the three-dimensional position of the teaching point PD is corrected (step 207).

As described above, according to this embodiment, misalignment caused by thermal strain is corrected in a timely manner during the welding operation. Therefore, even if misalignment occurs in the workpiece during production due to the influence of thermal strain. The tool tip can be moved precisely along the weld line.

Further, if the robot driving shaft (wrist tip shaft) is operated only for measuring the position during welding by applying the conventional technique, the operation of the original operation program is affected. Further, since the operation robot is moved only for position measurement and then the operation tor tip is moved to the original teaching point, a time loss is large. According to the present embodiment, since it is not necessary to operate the wrist tip axis of the work robot when performing position measurement during welding, there is little influence on the operation of the work program, and time loss can be reduced. .

FIG. 1 is a diagram used for explaining the principle of the light cutting method. FIG. 2 is a diagram used for explaining the principle of the light cutting method. FIG. 3 is a diagram used for explaining the principle of the light cutting method. FIG. 4 is a diagram for explaining the prior art, and is a diagram for explaining an operation when the optical cutting method is applied to the welding robot. FIG. 5 is a diagram illustrating a first configuration example of the position measurement unit. 6A, 6B, 6C, and 6D are diagrams showing a second configuration example of the position measurement unit. FIGS. 7A and 7B are diagrams illustrating a first image and a second image sequentially captured by the imaging unit. FIGS. 8A and 8B are diagrams exemplifying a first image and a second image sequentially captured by the imaging unit at the time of teaching. FIGS. 8C and 8D are captured at the time of reproduction. It is the figure which illustrated the 1st image and the 2nd image which are sequentially imaged by a means. FIG. 9 is a flowchart illustrating the procedure of position measurement processing according to the embodiment, and is a flowchart illustrating the processing procedure during teaching. FIG. 10 is a flowchart illustrating the procedure of the position measurement process according to the embodiment, and is a flowchart illustrating the process procedure during reproduction. FIGS. 11A, 11B, 11C, and 11D are diagrams illustrating the operation of the welding robot. FIG. 12 is a flowchart illustrating a procedure of position measurement processing according to the embodiment, and is a flowchart illustrating a processing procedure during reproduction. FIGS. 13A, 13 </ b> B, and 13 </ b> C are diagrams illustrating image processing performed by the image processing apparatus. FIG. 14 is a diagram illustrating an overall configuration of a welding system including the welding robot of the embodiment. FIGS. 15A and 15B are perspective views showing an example in which the position measurement unit is attached to the welding robot. FIGS. 16A and 16B are diagrams illustrating the operation of the welding robot.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Welding robot, 11 Wrist tip axis, 20 Welding torch, 30 Position measurement unit, 40, 41, 42 Slit light source, 50 Camera, 80 Image processing device, 90 Robot controller

Claims (5)

A work tool is provided on the wrist tip axis of the work robot, and a position measurement unit that performs position measurement by an optical cutting method is provided.
In the position measurement unit, a first slit light source, a second slit light source, and a first slit light source that project the first slit light and the second slit light that cross each other on the work target. An imaging means for capturing a first image including a light-cut image corresponding to the slit light and a second image including a light-cut image corresponding to the second slit light; and
With the wrist tip axis of the work robot fixed, the first slit light source projects the first slit light onto the workpiece, and the second slit light source projects the second slit light onto the workpiece sequentially. go,
With the wrist tip axis of the work robot fixed, the imaging means sequentially acquires the first image and the second image,
Based on the acquired first image and second image, the coordinate position on the first image and the coordinate position on the second image are converted into coordinate positions in the robot coordinate system, thereby An apparatus for measuring a position of a work robot, characterized by measuring a three-dimensional position of a work described in an operation program . A work tool is provided on the wrist tip axis of the work robot, and a position measurement unit that performs position measurement by an optical cutting method is provided.
Rotation that rotates the slit light source so as to obtain a slit light source that projects slit light toward the work to be worked and a first slit light and a second slit light that intersect on the work in the position measurement unit A mechanism and an image pickup unit that picks up a first image including a light cut image corresponding to the first slit light and picks up a second image including a light cut image corresponding to the second slit light; And
By operating the rotation mechanism while fixing the wrist tip axis of the work robot, the first slit light is projected onto the workpiece by the slit light source, and the second slit light is projected onto the workpiece by the slit light source. In order,
With the wrist tip axis of the work robot fixed, the imaging means sequentially acquires the first image and the second image,
Based on the acquired first image and second image, the coordinate position on the first image and the coordinate position on the second image are converted into coordinate positions in the robot coordinate system, thereby An apparatus for measuring a position of a work robot, characterized by measuring a three-dimensional position of a work described in an operation program . When teaching the operation program of the work robot, measure the three-dimensional position of the reference point on the master workpiece,
When replaying the operation program of the work robot, measure the 3D position of the reference point on the workpiece,
Calculating a positional deviation between the three-dimensional position of the reference point measured for the workpiece and the three-dimensional position of the reference point measured for the master workpiece;
3. The work robot position measuring apparatus according to claim 1, wherein the position of the teaching point described in the operation program is corrected based on the calculated positional deviation. At the time of teaching to teach the operation program of the work robot, the three-dimensional positions of a plurality of reference points on the master work corresponding to the plurality of teaching points described in the operation program are measured,
When reproducing the operation program of the work robot, the three-dimensional positions of a plurality of reference points on the workpiece corresponding to the plurality of teaching points described in the operation program are measured,
Calculating a positional deviation between the three-dimensional positions of the plurality of reference points measured for the workpiece and the three-dimensional positions of the plurality of reference points measured for the master workpiece;
3. The work robot position measuring apparatus according to claim 1, wherein the positions of a plurality of teaching points described in the operation program are corrected based on the calculated positional deviation. 5. The position measuring apparatus for a work robot according to claim 4, wherein the three-dimensional position of the reference point corresponding to the teaching point is measured when the operation program for the work robot is reproduced.

Images