JPS61199108A - Method and device for robot teaching - Google Patents

Abstract

PURPOSE:To teach easily the position, the attitude, etc. of a working tool by calculating a plane including two working points on a working line and an auxiliary point near the working line and obtaining the attitude of the working tool and the position of its wrist part on a basis of the direction of this plane and teaching them. CONSTITUTION:In a robot teaching device 1, drawing information is displayed on a CRT display device 4. An operator uses a mouse 6 to input the first working point A (start point) on the working line while watching the picture on the display device 4 and inputs the second working point B (end point) to display it. When drawing information desirable for input of the auxiliary point near the working line is displayed, the operator selects and inputs a right auxiliary point R or a left auxiliary point L in the right or the left when viewing an automobile body from a working tool 10. A computer 2 calculates a plane including points A, B, and R of L, and calculates the attitude of the tool 10 on a basis of the direction of this plane and calculates the position of the wrist part on a basis of this attitude. Thus, teaching is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a robot teaching method and apparatus for teaching the position, posture, moving speed, etc. of a working tool attached to the wrist of the robot.

"Prior art and its problems" Robot teaching methods include online teaching and offline teaching, but offline teaching is preferable from the viewpoint of not having to stop the production line.

Off-line teaching methods include direct teaching, in which offline robots are operated manually, and indirect teaching, in which teaching is performed through numerical values, language, graphics, etc., and each method has its own strengths and weaknesses.

The advantage of direct teaching is that the difficulty of teaching does not change much from simple movements to relatively complex movements. However, since the operation is performed manually, there is a limit to the complexity of the operation and the shortening of the teaching time. Additionally, there are drawbacks such as the need for offline robots and their installation locations.

On the other hand, the advantage of indirect teaching is that offline robots and their installation locations are not required. However, there is a drawback that the difficulty of teaching suddenly increases when the motion becomes a little complicated.

One of the reasons for this is that it is difficult to teach the posture of the work tool. In other words, teaching the work line itself can be done indirectly, such as by plotting work points on the drawing of the workpiece, but it is possible to use a relatively direct method, whereas the posture of the work tool is taught using a space that does not appear on the drawing. Therefore, a direct method cannot be used, and it is literally an indirect method such as numerically inputting a group of coordinates, which makes teaching difficult.

For this reason, for robots that perform relatively complex movements,
Indirect teaching has not been used much in the past.

"Purpose of the Invention" This invention was made in view of the above circumstances, and aims to provide a robot teaching method and device that makes it possible to easily teach the position, posture, etc. of a working tool. .

"Structure of the Invention" The robot teaching method of the present invention is a method for teaching the position, posture, etc. of a working tool attached to the robot's wrist, and the method includes two work points selected on a work line and the corresponding work. A plane containing the auxiliary points selected near the line is calculated, the posture of the work tool is calculated and taught based on the orientation of the plane, and the position of the wrist is calculated based on the posture. It is characterized by teaching. Also,
The robot teaching device of the present invention is a device for teaching the position, orientation, etc. of a work tool attached to the wrist of a robot, and is a device for teaching the position, posture, etc. of a work tool attached to the wrist of a robot, and is a device for teaching the position, orientation, etc. of a work tool attached to the wrist of a robot, and is a device for teaching the position, orientation, etc. of a work tool attached to the wrist of a robot. an input means for inputting the position of at least one auxiliary point, and a plane including the two work points and the position of the auxiliary point inputted by the input means,
The present invention is characterized in that it is provided with calculation means for calculating the posture of the working tool based on the orientation of the plane, and calculating the position of the wrist of the robot based on the posture.

The above-mentioned input means include means for inputting through images or drawings, such as a light ben or a mouse.

Although it is preferable to use a digitizer or the like, numerical input means such as a numeric keypad may be used, and if desired, the working point and the auxiliary point may be directly input using direct teaching means.

It is preferable to use a computer as the calculation means.

"Example" The present invention will be further explained in detail below based on the example shown in the drawings. Here, FIG. 1 is a schematic structural explanatory diagram illustrating a robot teaching device and a robot device according to an embodiment of the present invention, and FIG. 2 is a flowchart of essential parts of the operation of the robot teaching device shown in FIG. 1. Fig. 3 is an explanatory diagram of the work of painting an automobile body, Fig. 4 is an explanatory diagram showing an example of an image display in the robot teaching device shown in Fig. 1, and Fig. 5 is an explanatory diagram showing an example of another image display. 4 is a diagram equivalent to FIG. 4, FIG. 6 is a conceptual explanatory diagram when this invention is applied to perform fillet welding, FIG. 7 is a diagram equivalent to FIG. 4 in the case shown in FIG. 6, and FIG. 8 is a diagram equivalent to FIG. FIG. 5 is a diagram corresponding to FIG. 5 in the case shown in FIG. 6;

Note that this invention is not limited to this.

As shown in FIG. 1, a mouth pot teaching device 1 according to an embodiment of the present invention includes a computer main body 2, a memory 3, a C.
It consists of an RT display 4, a keyboard 5, and a mouse 6. As explained below, the CRT display 4
．． The keyboard 5 and mouse 6 correspond to input means, and the computer main body 2 corresponds to calculation means.

The computer main body 2 is connected to a robot control device 12, and the robot control device 12 has a memory 13. It is connected to a control panel 17 and a robot 18.

Based on the data taught by the robot teaching device 1, the robot control device 12 controls the robot 18, and the robot 18 controls the working tool 10 attached to the front end of its wrist.
(for example, a paint gun or welding torch) to perform the desired task.

Next, the operation of the robot teaching device 1 will be explained using a specific example with reference to FIGS. 2 to 5.

For the sake of simplicity, a specific example assumes that a painting operation is performed on an automobile body W using a paint gun as shown in FIG. 3, and drawing information of the automobile body W is stored in the memory 3 in advance.

When the teaching process starts, the computer main body 2 displays a list of stored drawing information on the CRT display 4, and the operator looks at the list and selects appropriate drawing information, and uses the keyboard 5 or mouse 6 to edit the drawing. The information is called up and displayed on the CRT display 4. Conventionally known CAD technology can be used for such a drawing calling operation. This is step Sl.

The drawing information called up in step S1 is displayed on the screen 4' of the CRT display 4, for example, as shown in FIG.
will be displayed. Note that the display at the upper right of the screen 4' indicates which part of the automobile body W is being displayed.

The operator selects the first work point A while looking at this screen 4'. The first work point A is the starting point of the work, so in principle you must select a point on the work line.0 To input the selected first work point A, for example, move the mouse 6 and point it on the screen. To perform this input accurately, move the cursor point, check the coordinate values (Ax, Ay, At) displayed on the screen as the cursor point moves, and then give the reading instruction. , the drawing information in which the main parts are further enlarged may be extracted and inputted.As such a method, a conventionally known CAD method can be used.

When the input of the first work point A is completed, the computer body 2 automatically enters the state of waiting for the input of the second work point B, so it is only necessary to input the second work point B in the same way.This second work point B has the meaning of the end point of the work.

These are step S2 shown in FIG.

When the input of the first work point A and the second work point B is completed, the next step is to input the auxiliary points, and the auxiliary points generally display a drawing showing a different space from the work point on the screen 4'. Step S3 is a step of selectively displaying drawing information preferable for inputting auxiliary points on the screen 4'.

When drawing information suitable for inputting an auxiliary point is displayed on the screen 4', the operator selects and inputs an auxiliary point. If the object to be worked on is a simple plane, it is sufficient to have one point near the work line, but one point is not sufficient when the object includes curved surfaces, ridges, valleys, etc. In this embodiment, a case will be explained in which two points are taken.

That is, the auxiliary points include a right auxiliary point R and a left auxiliary point.

When looking at the vehicle body W from the power tool 10, the right auxiliary point R is selected on the right side in the direction of movement of the power tool 10, and the left auxiliary point is selected on the left side. As will be understood according to the following description, the orientation of the power tool 10 is defined by selectively selecting only the right auxiliary point R or the left auxiliary point.

The selection method for the right auxiliary point R is the first work point A and the second work point B.
It is preferable to select a point on the wall on the right side of the work line that is near the middle of the work line between Preferably, the specific input operation for the auxiliary points R and L is the same as the input operation for the work points A and B, and the process for 0 or more is step S4 shown in FIG.

When the work points A and B and the auxiliary points R and L are inputted as described above, the computer main body 2 calculates the right plane α and the left plane β according to the following procedure.

That is, the coordinates of points A, B, and R are (A.

, Ay, At ), CB+c, BF+ Bt ), (R
xr Ry l Rz ), then points A, B, H
Create a four-dimensional simultaneous linear equation by substituting the coordinates of E, F, and G into equation (1), and do not become O at the same time.

By determining H, the equation of the right plane α is obtained.

Ex+Fy+Gz+H　0・−・−−(1) As a specific calculation method, for example, solve X, 7. E as each coefficient of Z.

F, G can be obtained, and H can be obtained as a constant term.

Similarly, the coordinates of points A, B and the point (LX, Ly +L,)
From the equation of the left plane β, %Formula %(2) The above is step S5 shown in FIG.

Next, the computer main body 2 calculates a division direction that equally divides the angle formed by the right plane α and the left plane β.

That is, first obtain the unit normal vector (α1.α1.α3) of the right plane α from E, F, and G.

As a specific calculation method, for example, 8-1E7=1;Ken;Ishi7°, α+ -E/Aα
It can be obtained by z-F/A and α3-G/Δ.

Similarly, to J, let L to the unit normal vector of the left plane β (
β1. β2. β, ) is obtained.

From these unit normal vectors, the division vector in the division direction (S+, S2, Sz) - (α1 + β1° α2+
β2. α3+β3) is obtained, and a unit division vector (s+, A31 A3) is obtained from this division vector.

As a specific calculation method, for example, rT −Ell, s + −S + /IT'2 ”
32/n, II) -83/n.

Next, the computer main body 2 calculates the work line vector (M+ + M21M3) - (B1 - A) from the work points A and B.
I, B2-A2. B3 A3) is obtained, and the previously obtained division vector is later multiplied by this working line vector to obtain the cross product vector (11, 12+13).

As a specific calculation method, for example, Calculate from

Next, with the first work point A as the base point, the coordinates of the point P pointed to by the cross product vector (P K I P y r Pz )
−(Ax +1+ + Ay ”12r Ax +1
3) is determined, and it is determined whether the point P and the right auxiliary point R are on the same side of the plane T formed by the division vector and the work line vector.

As a specific calculation method, for example, the coordinate value P g + P of point P is set to
Determine whether or not the above sign when substituting each of y and P t and the above sign when substituting the coordinate value R + c + Ry + Rt of the right auxiliary point R match or not. If they match, they are on the same side, and if they do not match, they are on different sides.

If the point P and the right auxiliary point R are on the same side, the direction of the division vector happens to coincide with the direction of the working tool IO, so the basic direction vector (1,,12,1:+
) one unit division vector i.e. (1+, 12.11)
The basic direction vector (t+, t2+
t3) m one unit division vector, ie (t+, t2.
tx )−(−1++−”2*−s3).

Each component t1 of the basic direction vector obtained in this way
．． "2+t3 is the direction cosine of the basic posture of the working tool 10.

The above is step S6 shown in FIG. 2.

As shown in FIG. 5, the computer main body 2 displays an arrow 20 representing the basic direction vector obtained in step S6 in correspondence with the drawing of the automobile body W. This is step S7 shown in FIG.

Although the direction of the arrow 20 shown in FIG. There are cases where the user wants to stand the work tool 10 a little more vertically (especially when it is desired to stand up the welding torch during welding work). Step S8 shown in FIG. 2 is a process for correcting the attitude of the power tool 10 in such a case. For example, while viewing the screen shown in FIG. 5, select the forward tilt angle θ using the mouse 6, gradually increase or decrease the displayed value on the screen, stop at the desired value, and set the forward tilt angle θ. Just instruct them to set it as . A similar correction instruction may be given to the angle ψ at which the power tool 10 is raised in the vertical direction.

When the posture correction input is completed, the computer main body 2 adjusts the length of the power tool 10 to the corrected posture.

Calculate the position of the robot's wrist by taking into account the tip gap, etc. This is step S9.

Next, since the computer main body 2 requests a speed input, the operator responds by inputting the working speed between the two points A and 8 via the keyboard 5, for example. This is the second
This is the step SIO shown in the figure.

When the above operations are completed, the computer main body 2 stores the first work point A, the second work point B, the direction cosine 1 wrist position, and the work speed in the memory 3.

This is step 311 shown in FIG.

If the area to be taught is only between the first working point A and the second working point B, the teaching work is completed.

However, if there is another work line that you want to teach after the second work point B, return to the first step S1 and repeat the same process as above.The second time, set the second work point B as the first work point, and then It is only necessary to newly set a second work point at .In this way, a long continuous work line can be taught. Further, by keeping the distance between the two points A and B short, it is also possible to teach a curved work line.

During actual work, the teaching data stored in the memory 3 is transferred to the robot control device 12, and the robot control device 12 uses the transferred teaching data to control the robot 18.
calculates the operating angle, etc. of each arm, performs interpolation between work points, etc., and stores these data in the memory 13; Based on robot 18
operate.

Note that a conventionally known inverse conversion method may be used to create actual operation data of the robot 18 from the teaching data.

FIG. 6 shows a case where the present invention is applied to horizontal fillet welding. Further, FIGS. 7 and 8 show examples of display screens for teaching this horizontal fillet welding. It will be easily understood that these FIGS. 6, 7, and 8 correspond to the aforementioned FIGS. 3, 4, and 5.

In other embodiments, work points and auxiliary points are input by pointing a point on the drawing displayed on the CRT display 4 with a light ben, or working points are input by pointing a point on the drawing with a digitizer. For example, there is a method for inputting auxiliary points.

Furthermore, although it can be said to be an intermediate teaching method between indirect teaching and direct teaching, there is a method in which the work tool 10 is actually moved over the workpiece to teach the work point or auxiliary point, as if teaching. In this case, since the posture of the working tool 10 itself is not taught, it cannot be called direct teaching, but the working point itself is directly taught. If such a teaching method is adopted, it is possible to move the power tool 10 by focusing only on its tip without worrying about the posture of the power tool 10, which has the effect of reducing the burden on the operator.

"Effects of the Invention" According to the present invention, there is provided a method for teaching the position, orientation, etc. of a work tool attached to the wrist of a robot, which includes two work points selected on a work line and the vicinity of the work line. A plane containing these points is calculated from the auxiliary points selected in
Furthermore, there is provided a robot teaching method characterized by calculating and teaching the position of the wrist based on the posture, and a device for teaching the position, posture, etc. of a working tool attached to the wrist of the robot. an input means for inputting the positions of two work points selected on the work line and at least one auxiliary point selected near the work line; Calculating means calculates a plane including these from the position, calculates the posture of the work tool based on the orientation of the plane, and calculates the position of the wrist of the robot based on the posture. A teaching device for a robot is provided, which allows the basic posture of a working tool to be easily obtained by selecting points.
In addition, since the position of the robot's wrist can be obtained, the difficulty of teaching the posture of a work tool, which was a bottleneck when teaching through images or drawings, can be overcome, even when performing complex movements. This has the effect of making it easier to teach directly and indirectly through images and drawings.

This greatly increases the practicality of offline and indirect teaching, and brings about many effects at once, such as improved productivity, space savings, reduced teaching time, and increased sophistication of one task.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural explanatory diagram illustrating a robot teaching device and a robot device according to an embodiment of the present invention, FIG. 2 is a flowchart of essential parts of the operation of the robot teaching device shown in FIG. 1, and FIG. FIG. 4 is an explanatory diagram showing an example of an image display in the robot teaching device shown in FIG. 1, and FIG. 5 is an explanatory diagram showing an example of another image display. Figure 4 is a diagram equivalent to Figure 4, Figure 6 is a conceptual explanatory diagram when this invention is applied to perform fillet welding, Figure 7 is a diagram equivalent to Figure 4 in the case shown in Figure 6, and Figure 8 is a diagram equivalent to Figure 6. 5 is a diagram corresponding to FIG. 5 in the case shown in FIG. (Explanation of symbols) 1... Robot teaching device 2... Computer body 3... Memory 4... CRT display 5... Keyboard 6... Mouse.

Claims (1)

[Claims] 1. A method for teaching the position, orientation, etc. of a work tool attached to the wrist of a robot, which includes two work points selected on a work line and a position selected near the work line. The present invention is characterized by calculating a plane including these points from the auxiliary points, calculating and teaching the posture of the work tool based on the direction of the plane, and calculating and teaching the position of the wrist based on the posture. A teaching method for robots. 2. A device for teaching the position, posture, etc. of a work tool attached to the wrist of a robot, which includes the positions of two work points selected on the work line and at least one auxiliary point selected near the work line. an input means for inputting , and a plane containing the two work points and the auxiliary point inputted by the input means is calculated, the posture of the work tool is calculated based on the orientation of the plane, and the posture is adjusted to the posture. 1. A robot teaching device comprising: arithmetic means for calculating the position of the robot's wrist based on the above information. 3. The robot teaching device according to claim 2, wherein the input means is a means for inputting via images or drawings. 4. The input means inputs the two positions of the right auxiliary point and the left auxiliary point on both sides of the work line as auxiliary points, and the calculation means inputs the two positions of the right auxiliary point and the right auxiliary point input by the input means. Calculate the right plane that includes them from the positions of the points, calculate the left plane that includes them from the positions of the two work points and the left auxiliary point, and divide the plane opening angle between the right and left planes equally. The robot teaching device according to claim 2 or 3, wherein the dividing direction is calculated and the dividing direction is set as the direction of the basic posture of the working tool.