JPS61100809A - Three-dimensional teaching device of robot - Google Patents

Abstract

PURPOSE:To improve the working ratio of a robot, by providing spot light sources and an image pickup device, displaying each spot light and teaching point in a CRT display section, calculating movement information, etc., from the displayed information, and successively designating teaching points by means of a picture image identifying circuit. CONSTITUTION:A teaching device displays information of each spot light S1-S4 and each teaching point on a work 8, picked up by means of a camera 4. The picture image data are sent to a picture image identification circuit 16 where the brightness and darkness of the data are identified in plural steps. After the identification, the data are sent to a control section 17 equipped with a joy stick 18. The teaching operation of a robot is performed in such a way that, after each spot light source 11a-11d is turned on, a working head is moved to a teaching point and the display in the CRT15 is confirmed, and then, the coordinates and attitude data of the working head are stored in a storage section by designating and commanding the displayed teaching point by means of the joy stick 18. Moreover, a further bright teaching point is automatically designated together with the next teaching point and the working head is successively moved to newer teaching points, and thus, the teaching is executed automatically.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a three-dimensional teaching device for a robot, and in particular, the present invention relates to a three-dimensional teaching device for a robot, and in particular, the present invention relates to a three-dimensional teaching device for a robot. The present invention relates to a three-dimensional teaching device for a robot that continuously teaches the position of each successive teaching point, together with the inclination angle of the workpiece surface on which the teaching point is drawn, to the robot in a non-contact manner.

[Technical background of the invention and its problems] For example, in a robot installed on a factory assembly line or an industrial robot installed in a material cutting or processing process, ° the robot is It is necessary to teach the moving and operating procedures of the processing head in accordance with the three-dimensional shape of the workpiece. A device that teaches the three-dimensional movement of the processing head is called a three-dimensional teaching device. For example, in a CO2 laser cutting robot, a magnetic sensor is installed near the processing head to teach the workpiece to be cut, such as a steel plate. The distance between the processing head and the workpiece surface was calculated based on the current value.

Therefore, the actual teaching work involves the operator visually approaching the machining head to a teaching point such as a scratched line drawn on the workpiece surface while operating the teaching pendant, and also visually determining the laser irradiation angle of the machining head. Adjusting the posture of the machining head so that it is perpendicular to the workpiece surface at the teaching point, and setting the distance between the machining head and the teaching point on the workpiece surface to a constant value using the aforementioned magnetic sensor. It was necessary to carry out three tasks through trial and error.

However, when a worker visually performs the teaching task consisting of three tasks at each teaching point as described above, there are differences in set values such as the distance to the processing head and the attitude angle of the processing head between each teaching point. There are problems that arise. As a result, there is a risk that the cut surface of the workpiece may be uneven or that some areas may not be cut.

In addition, if the above-mentioned teaching work is performed carefully and accurately in order to avoid the above problems, the teaching work time will increase and the operating rate, which indicates the percentage of time the robot is actually performing cutting work, will decrease. There was a problem with the decline.

It also required workers who were skilled in operating robots.

[Object of the Invention] The present invention has been made based on the above circumstances, and its purpose is to continuously move the head of a robot in a short period of time without requiring a skilled worker. Automatically performs continuous movement along the drawing line, constant control of the attitude angle of the head relative to the work surface during movement, and constant control of the distance between the head and the work surface. To provide a three-dimensional teaching device for a robot, which can teach a robot visually, can accurately and efficiently perform teaching work to the robot, and can greatly improve the operating rate of the robot.

[Summary of the Invention] The three-dimensional teaching device for a robot of the present invention includes three or more spot light sources that irradiate the surface of a workpiece with a spot at a predetermined irradiation angle near the head, and a spot light source on the workpiece that is irradiated with each of the spot light sources. An R imaging device is provided to image the spot light and each continuous teaching point drawn on the workpiece, and further a cathode ray tube display unit is provided to display each spot light and each teaching point imaged by the imaging device. An image identification circuit is provided for identifying the brightness and darkness of each teaching point displayed on the cathode ray tube display section in a plurality of stages. Then, from the two-dimensional positional relationship and irradiation angle of each spot light displayed on the CRT display, the distance and inclination angle of the head to the reference position determined by the positional relationship between each spot light on the workpiece and the workpiece surface are calculated. When the first teaching point among the teaching points calculated and displayed on the CRT display is specified, the two-dimensional positional relationship between the specified first teaching point and the reference position is automatically measured, and the The movement information of the head to the first teaching point is calculated using the measured positional relationship and the distance and inclination angle between the blades at the reference position, and the head is moved to the first teaching point based on the calculated movement information. The posture of the moved head is controlled based on the inclination angle, and furthermore, pixels having the same brightness as the teaching point are drawn from among the pixels around the teaching point already identified by the image recognition circuit. The teaching points identified by the teaching point are sequentially automatically specified to be replaced with the first teaching points, and the head is sequentially moved to the sequentially automatically specified teaching points to sequentially control the posture.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the entire device in which the three-dimensional teaching device of the embodiment is incorporated into a CO2 laser cutting robot, and numeral 1 in the figure is the robot body.

This robot body 1 is provided with a processing head 4 that irradiates a laser beam that is controlled to move three-dimensionally by moving arms 3a and 3b above a table 2 on which a workpiece such as an iron plate is set. There is. This processing head 4 is
As shown in the figure, a bearing attached to the tip of the movable arm 3b is rotatably connected to the part 5 via a support 6. A teaching device main body 7 is fixed to the opposite surface of the support 6 from the processing head 4. Hey,
Since the movable arm 3b is configured to be rotatable around the axis, the processing head 4 and the teaching device main body 7
is controlled to move three-dimensionally at a position above the table 2, and its posture is also freely controlled. Further, 8 in the figure is a three-dimensional workpiece set on the table 2, and a marking line 9 is drawn on the surface of this workpiece 8, and the workpiece 8 is cut along this marking line 9. shall be taken as a thing.

FIG. 4 shows the teaching device main body 7, in which four spot lights (l! 11a, 11b, 11c, and 11d are fixed. Each spot light source 11a, 11b, 11c,
The light beam irradiated downward from 11d is reflected by mirrors 12a and 1.
The light beams 2b, 12c, and 12d are focused on one point (focal point F) on the axis of the cylindrical container 10, and then irradiated onto the surface of the workpiece 8 to form spot lights S1, 82, 83, and 84, respectively.

In addition, each spot light 8 formed on the surface of this work 8
Each teaching point 13 consisting of 1 to S4 and the above-mentioned sharp line 9
A camera 14 for taking images is attached to the center of the cylindrical container 10.

FIG. 1 is a schematic configuration diagram showing the entire teaching device, and information on each of the spot lights 81 to S4 imaged by the camera 14 and each teaching point 13 is displayed on the cathode ray tube 15. Each spot light $1~S displayed on this cathode ray tube 9
4 and the image data of each teaching point 13 are sent to the image identification circuit 16.
sent to.

This image identifying circuit 16 identifies the brightness and darkness of the input image data in multiple stages, and determines the two-dimensional position (
coordinates) into numerical data and sends it to the control section 17, which is comprised of a microcomputer or the like at the next stage. A joystick 18 is connected to the control section 17 for inputting digital data to the control section 17 while monitoring the image displayed on the cathode ray tube 15.

Next, the operating principle of this teaching device will be explained.

First, in FIG. 1, the line connecting the spot light sources 11a and 11C is taken as the Y axis, and the spot light source 11d.

Assuming that the line connecting 11b is the Y-axis, this Y-axis and a plane including the Y-axis are orthogonal to the optical axis 19 of the camera 14. This optical axis 19 is used as two axes, and the focal point F and the workpiece 8 on this Z axis are
The coordinate value of the intersection point Pa (reference position) with respect to the surface is Zo
If α is the angle at which the spot light beams from each of the spot light sources 11a to 11d intersect with the two axes, then the cross-sectional views on the Y axis and the plane including the Y axis are shown in FIGS. 5(a) and 5(b), and the Y axis, Y axis.

The overall relationship on the Z axis is shown in Figure 6. In FIG. 5 (a), the Y coordinates of each spotlight S2 and s4 are Y
2, Y4, and the intersection point P of the workpiece 8 surface as shown in the figure.
If the inclination angle around the Y-axis at G is φ, then in the figure, the actual value of Y4 is the value. Since the irradiation angle α is a constant value, the seven coordinate values Za y of the intersection point PG are determined by Equation (1) by simple geometric considerations using the similarity of triangles.

ZOy = 2Y2 Y4 / (Y2-Y4) t
ana... (1) Note that the sign of the Z axis is positive in the direction of the camera 14.

Similarly, in Fig. 5<b), let the X coordinates of the spot lights S1 and S3 be Xl, Xl (actual values are negative values), and the intersection point P
If the inclination angle around the Y-axis of the surface of the workpiece 8 at a is θ, the value of the Z-axis coordinate zOX of the intersection PG is expressed by equation (2).

Za x = 2X I Xl / (Xi
-Xl) tana... (a Theoretically, the above angle coordinate values ZOY and ZOX should match, but since they are obtained from actual measurements, they may not match. Therefore, the intersection point The 7-coordinate value Zo of Pa is expressed as the average value of equation (1) and equation ('2J), as shown in equation (3).

Zo = (Zo Y+ZOX)/2= [
Y2 Y4 / (Y2 - Y4 ) + XI
Xl / (Xt - Xl) ] / ta
na...(3) Note that the distance Zs between the camera 14 and the focal point F is a predetermined value depending on the mechanical configuration.

In addition, the inclination angles φ and θ around the X-axis and Y-axis of the surface of the workpiece 8 at the intersection P0 in FIG. (5)
It can be found as shown in the formula.

φ= -tan' [(Y2 +Y4) /(Y
2-Y4) tana] -・-・-(4)
θ” jan” [(Xi +X3) /(×
1-X3) jan(Z]-=15) However, the signs of φ and θ are negative in the case of inclination as shown in FIG.

In this way, each coordinate value Xt of each spot light S1, 82, 83, 84 displayed on the cathode ray tube 15.

By determining Y2, Xl, and Y4, the optical axis (Z
Coordinate value Zo of intersection point PO of axis) 19 with respect to workpiece 8 surface
And the inclination angles φ and θ of the workpiece 8 at the intersection point PO can be calculated.

Next, as shown in FIG. 7, the first teaching point 13 (PI) (XPI, . . .
Ypt, Zps) (7) Find the Z coordinate value Zps.

Note that the instruction for the first teaching point P1 is made by operating a joystick 18 connected to the control section 17 on the cathode ray tube 15. Therefore, the first teaching point P1 is the intersection PD
, and the above-mentioned inclination angles φ and θ are PI, Pa
Assuming that there is no significant change between
The coordinate value Zp is the Z coordinate 1iiZo of the intersection Pa, and the change due to the above slope (-Yp1tanφ, -Xpltanθ
) is added. Each inclination angle φ, θ is (4)i5)
Since it is determined by the formula, the two-coordinate value Zρ1 of the first teaching point Pp finally becomes the formula (6).

Zp1= (YPI Y2 +Y2 Y4 +Y4 Y
PI ) / <Y2-Y4 ) jan(Z + (Xp I Xl +X1 , Xl +X
3 XPI )/(Xl-Xl) tana
-16) Therefore, the three-dimensional coordinates of the first teaching point P1 <XPI, YPI, Zpt) are
~Two-dimensional positional relationship of S4 (Xr, Y2, Xl
.

Y4) and the irradiation angle (α) of the light beam. therefore,
Movement information for moving the processing head 4 of the robot from the currently stopped position above the intersection PII to the position above the first teaching point Pp can be obtained from the coordinate relationship between the intersection point Po and the first teaching point Pp. become.

Based on such an operating principle, the control section 17 is configured to execute a teaching process for the robot according to the flowchart of FIG. 8.

That is, when the power is turned on and various initial processes are completed, the four spot lights S1 . S2.33.

84(7) Each coordinate position fiXt, Y2, Xl,
Y4 (1) Read the value via the image identification circuit 16.

Next, using each coordinate value read above at 02, '(4)
, (Optical axis 19 (Z axis) on the surface of workpiece 8 in formula 51
The inclination angles φ and θ at the intersection point PG are calculated. When the calculation of the inclination angles φ and θ is completed, the value Za of the Z coordinate of the intersection point PG is calculated using equation (3) in Q3.

When the above process is completed, joystick 18 is installed in Q4.
Wait for the instruction of the first teaching point P1 by the operation. When the instruction for the first teaching point P1 is input, the coordinate value XP1 of the teaching point P1 designated as the first teaching point is determined in Q5. YP1 is read via the image identification circuit 16 described above. Coordinate value Xpl, Y
Once pt is determined, in Q6, the seven coordinate values Zp1 of the first teaching point P1 are calculated using equation (6). First teaching point P1
When the coordinates (Xpl, Ypt, ZPl) of
In step 7, movement information consisting of the direction and distance of the robot to the processing head 4 is calculated from the coordinate relationship between the intersection point Pa and the first teaching point Pp, and the processing head 4 is moved according to the movement information.
is moved to a position above the first teaching point P1. In this case, the position is controlled so that the distance between the focal point F and the first teaching point P1 matches the distance between the first focal point F and the intersection point PG.

Next, in Q8, the attitude of the processing head 4 is controlled to a predetermined value according to the inclination angles φ and θ. When posture control is completed, this first teaching point P! The three-dimensional coordinates and posture angle data of the processing head corresponding to are stored in the storage unit. This completes the teaching process for the first teaching point P1.

When the teaching process for the first teaching point P1 is completed, another teaching point P near the first teaching point P1 displayed on the cathode ray tube 15 is searched by QIO. In this searching operation, the image identification circuit 16 identifies the brightness level of the first teaching point P1, and the processing head 4
1, this first teaching point P1 is set as a new intersection Po. Next, the image identification circuit 16 identifies the pixel closest to the navigation brightness level among the adjacent pixels as the adjacent teaching point PN. The teaching point PN is automatically designated as a new teaching point P1 after the machining head 4 completes the movement.

And the new first teaching point P! The above-mentioned teaching process is executed for the automatically designated teaching point PN.

Then, when the teaching point PN reaches the final teaching point PE at Qll, all teaching processing for this robot ends.

With the robot three-dimensional teaching device configured in this way, the robot operator turns on the power of the teaching device and lights each of the spotlights 111i11a, 11b,
11c and 11d, move the processing head 4, for example, to a position near the first teaching point P1 of the marking line 9,
It is only necessary to confirm that this first teaching point P1 is displayed on the cathode ray tube 15, and then specifying the first teaching point P1 using the joystick 18. When this first teaching point P1 is specified, the processing head 4 automatically moves to a position above the first teaching point P1, maintains a predetermined distance from the teaching point P1, and stops at a predetermined attitude angle. . and,
The coordinates and posture data of the processing head 4 with respect to this teaching point P1 are stored in the storage section. When the storage is completed, the next brightest teaching point P is automatically designated as the first teaching point P1, and the processing head 4 moves to this new first teaching point P1. In this way, the processing head 4 moves to new teaching points PN one after another.

In this way, since teaching is automatically executed simply by the operator instructing the first teaching point P1, it is possible to greatly improve teaching efficiency. As a result, the operating rate of the robot can be significantly improved.

In addition, the operator can visually check the machining head 4 for each teaching point P.
Since it is not necessary to set the position and orientation of □, the teaching accuracy can be improved, and the machining accuracy of the workpiece 8 can be improved.

Note that the present invention is not limited to the embodiments described above. In the embodiment, the joystick 18 was used as a means for specifying the first teaching point P1, but any device that can electrically specify an arbitrary position (coordinates) on the cathode ray tube 15, such as a light ben, digitizer, or trackball, may be used. good. Further, the number of spot light sources installed is not limited to four, but may be three or more.

In addition, instead of the four spot light sources of the embodiment, light is irradiated onto the workpiece in a ring or circle shape, and the intersection of the ring or circle and the seat W and axis of the cathode ray tube is set to the four spots described above. It may also correspond to light.

Furthermore, in addition to CO2 laser cutting robots, the present invention can be incorporated into welding robots, sealant coating robots, and other robots.

[Effects of the Invention] As explained above, according to the present invention, the robot head can be moved continuously along a continuous scribing line in a short period of time without requiring a skilled worker. The robot can be automatically taught the task of constantly controlling the attitude angle of the head relative to the workpiece surface during operation, and the task of controlling the distance between the head and the workpiece surface to be constant. Therefore, teaching work for the robot can be performed accurately and efficiently, and the operating rate of the robot can be significantly improved.

[Brief explanation of drawings]

The figures show a three-dimensional teaching device for a robot according to an embodiment of the present invention. FIG. 1 is a schematic diagram of the overall configuration, FIG. 2 is a perspective view of the entire robot, and FIG. 3 is a diagram showing the same teaching device. Figure 4 is a cutaway perspective view showing details of the main part, Figures 5 and 6 are diagrams for explaining the operating principle of the device, and Figure 7 is a cathode ray tube. FIG. 8 is a flowchart showing the operation. 1...Robot body, 4...Processing head, 7...
Teaching device main body, 8... Work, 9... Marking line, 11a, 11b, Ilc, 11d 2-pot light source, 13... Teaching point, 14... Camera, 15... Braun tube, 16 ...Image identification circuit, 17...Control unit, 18...Joystick, 19...Optical axis, F.
...Focus, PO...Intersection, Pl...First teaching point,
Sl, S2.83. S4...Spot light. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 4 Figure 5 (a) (b) Figure 6 Figure 7

Claims (1)

[Claims] In a robot that automatically moves the head to each of the teaching points on the workpiece while sequentially moving the head to a plurality of continuous teaching points specified in advance on the workpiece, the robot automatically operates the head at three or more positions near the head. three or more spot light sources installed to illuminate the surface of the workpiece at a predetermined irradiation angle, and spot light on the workpiece installed near the head and irradiated by each of the spot light sources. and an imaging device that images each of the teaching points drawn on the workpiece, a cathode ray tube display unit that displays each of the spot lights and each of the teaching points that are imaged by the imaging device, and From the displayed two-dimensional positional relationship of each of the spotlights and the irradiation angle, calculate the distance of the head to a reference position determined by the positional relationship between the respective spotlights on the workpiece and the inclination angle with respect to the workpiece surface. a reference position calculation means for calculating a reference position of the teaching points displayed on the cathode ray tube display section; a specifying means for specifying a point; an automatic measuring means for automatically measuring a two-dimensional positional relationship between the first teaching point specified by the specifying means and the reference position; a movement information calculation means for calculating movement information of the head to the first teaching point using the distance between the head at the reference position and the inclination angle; a moving means for moving the head to the first teaching point based on the calculated movement information; an attitude control means for controlling the attitude of the head moved by the moving means based on the inclination angle; The image identification circuit searches for the pixel closest to the brightness of the teaching point from the pixels surrounding the first, identifies the adjacent teaching point, and automatically specifies sequentially to replace the adjacent teaching point with the first teaching point. 1. A three-dimensional teaching device for a robot, comprising: automatic designation means for sequentially specifying teaching points; and means for sequentially controlling the posture of the head by sequentially moving the head to teaching points sequentially designated by the automatic designation means.