JP2804474B2 - Teaching method for industrial robots - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is composed of three orthogonal axes and two rotation axes for controlling the angle of the arm tip, and at least five axes are simultaneously controlled by position information and posture information. The present invention relates to a method of teaching position information and posture information of an industrial robot, and more particularly to a method of simplifying the teaching method. (Prior art and its problems) Conventionally, as this kind of industrial robot,
As shown in JP-A-59-21491, a one-point directivity type 5-axis laser beam machine capable of arbitrarily changing the angle of a nozzle while fixing a laser irradiation position at one point is already known. This 5-axis laser beam machine has at least a 5-axis control system including three orthogonal axes X, Y, and Z for determining the position of the robot, and two rotation axes α and β for determining the nozzle angle. That is, the irradiation position and angle of the laser irradiated from the nozzle of the robot are freely controlled by the position information (X, Y, Z) and the rotation posture information (α, β). Then, when tracing and processing an arbitrary figure on a flat plate or a three-dimensional work, for example, the teaching head is moved in accordance with a scribe line drawn in advance on the work, and position information at each teaching point on the scribe line is processed. In addition, teaching movement control of the robot is performed by teaching rotation posture information of the teaching head. In such teaching, a worker usually has at least 5 points when the processing shape is a circle, and when the processing shape is a track,
10 points, 8 points in the case of a square, 16 points in the case of a square with a corner R, and many more teaching points as the figure becomes more complicated. For example, assuming that the teaching time takes 30 seconds per point, 150 seconds for a circle, 300 seconds for a track shape, and so on, the teaching operation takes much longer as the figure becomes more complicated. Even in the case of repeatedly processing these same-shaped figures at a plurality of locations on the work, the same number of teaching points must be taught at all positions on the score line for each of the same-shaped figures. In addition, the teaching work took a huge amount of time. In addition, since errors at the time of teaching for each point directly affect the processing of the robot that is played back, variations in the processing shape accuracy occur, and subsequent correction of various data requires a lot of time, resulting in lower processing efficiency. There were many problems, such as cause of the problem. Accordingly, the present invention is to solve the above-mentioned problems by simplifying the teaching work for various fixed figures and arbitrary free curved figures, thereby shortening the teaching time and facilitating the work. (Means for Solving the Problems) In the present invention, a plurality of types of graphic data are registered in advance,
At the time of teaching, by simply designating the registered figure data and teaching two points on the copy plane, that is, on the work, the teaching work of the figure copy position, copy direction and copy surface can be completed, and thereby teaching. Time can be greatly reduced, and in particular, repeated copying of the same figure or multiple copying of various figures on an arbitrary plane on a three-dimensional work can be performed easily in a short time. That is, the present invention is to register a plurality of types of graphic data in advance in a unique coordinate system unique to a robot, and to determine a first point for determining a specified graphic position among registered graphics and a direction of the graphic during teaching. By teaching the posture of the teaching head at the first point, which is the reference point of the figure, and the second point in the reference axis direction that determines the direction of the figure, the specified figure data can be read from the work, that is, from the copy coordinate system. The robot is finally converted into a coordinate system to obtain control position information of the robot. Next, an embodiment of the present invention will be described with reference to the drawings for a 5-axis laser beam machine. In FIG. 1, a main controller 1 of a laser beam machine is shown.
Are position and orientation data X, Y, Z, which determine the motion of the robot body based on teaching data and various types of processing data input from an external controller such as the CRT device 2.
Outputs α and β, and performs 5-axis simultaneous control of the robot. FIG. 2 shows a laser processing head 3 provided at the tip of the robot. The α-axis and the β-axis are fixed while the laser illumination position E determined by the coordinates of the X, Y, and Z axes of the robot's own coordinate system is fixed. By controlling the rotation of the head, a one-point directivity type head configuration in which the attitude of the nozzle 4 can be arbitrarily changed. For example, a hard disk having a large capacity memory is connected to the CRT device 2, and various basic patterns and plural types of graphic data having an arbitrary shape can be registered in the hard disk in advance. These graphic data are registered as coordinate data on the orthogonal X, Y, and Z axes of the robot-specific coordinate system as position information. The registration method of this figure data is direct teaching input, coordinate designation input from CRT, figure pattern input,
Alternatively, any input method such as input using an NC tape is possible. Here, input of a graphic pattern will be described. Frequently used graphic patterns, as shown in FIG.
For example, input of a circle, a track, a square, and a square with a corner R will be described. Each pattern operation control program for controlling the robot corresponding to each of these graphic patterns is incorporated in the hard disk in advance, and various graphic data are automatically created only by inputting a radius and a length. I have. In the case of a circle, the radius R and the depth of cut S are used. In the case of a truck, the radius R and the length U and the depth of cut S are used. In the case of a square, the lengths U and V of two sides and the depth of cut S are calculated.
In the square with a corner R, graphic data of various dimensions and shapes are registered by inputting the radius R, the lengths U and V of the two sides of the straight line portion, and the cut amount S, respectively. Also,
These graphic pattern, the reference point P ₁ and the reference axis L are respectively set. In addition, direct teaching input, CRT input, N
It is also possible to register free curve graphic data of an arbitrary shape other than the above-mentioned graphic pattern by inputting a C tape or the like. By registering graphic patterns of various dimensions and various graphic data of an arbitrary shape in this way, when teaching on a workpiece, two points (only one point in the case of a circle) are placed on a three-dimensional arbitrary plane. , The same figure locus as the designated figure data can be copied three-dimensionally only by teaching. Next, a teaching method for teaching a registered figure on a three-dimensional work will be described. First, prior to teaching, the nozzle 4 in FIG. 1 is removed and replaced with a teaching rod capable of designating the same coordinates as the tip of the nozzle. The processing head 3 in this state is called a teaching head. As shown in FIG. 4, for example, when the figure pattern is a circle, a circle pattern is designated, and only one point corresponding to the reference point P1 is set.
Two points are taught: a point corresponding to P1 and one point on a line L 'in the longitudinal direction of the figure corresponding to the reference axis L passing through this point. At the time of the first teaching at the first point, the teaching posture of the teaching head indicating the posture of the nozzle is made substantially coincident with the copy plane Wa in the normal direction. That is, by the teaching of the first point, the copy reference position information of the graphic pattern is taught and input, the copy plane information is taught from the teaching posture of the teaching head at this time, and the posture of the teaching head is directly used as the posture information of the nozzle. (Α,
β). At this time, by specifying the registered graphic data at the same time as teaching of the first point, for example, in the case of a circle, since the graphic pattern has no direction, the reference point P1
Only a point may be used, but in the case of another graphic pattern, the second point is taught after designating the graphic pattern,
The figure reference axis L 'direction, that is, the figure pattern direction is taught, and at the same time, a copy coordinate system described later is determined. Therefore, the designated graphic data is once copied to the copy coordinate system, and then the information (X, Y, Z,
α, β). As described above, when teaching a registered figure on a work, it is only necessary to teach the first point and the second point on the work surface Wa as shown in FIG. At the time of machining, the information (X, Y, Z, α, β) recorded by this teaching moves the entire circumference of the specified figure trajectory from the cut point specified at S at the time of registration, as shown in FIG. Then, the process returns to the incision point again, and the processing of the registered figure ends. This is a three-dimensional copy processing locus during laser processing. The above is performed by the following processing by the main body controller 1 shown in FIG. In FIG. 7, the robot-specific coordinate system (X, Y, Z
Axis) to the teaching coordinate system (x, y, z axes). Next, a copy coordinate system (x ′, y ′, and x ′) determined when teaching various figures to respective positions on the three-dimensional surface of the work.
The origin o 'of the z' axis) is translated so as to coincide with the origin O of the teaching coordinate system to obtain coordinate axes x ", y" and z "corresponding to the x ', y' and z 'axes. graphic data various registration, as for example, FIG. 8, on the x-y plane of the teaching coordinate system (robot unique coordinate system), the reference point P ₁ to the origin O, and the reference axis L direction x It is registered respectively by matching the axial direction. each coordinate point of the reference axis L 'line corresponding to the point and said pattern reference axis L corresponding to the reference point P ₁ are teaching on copying plane point = (X _o , y _o , z _o ) Point = (x _p , y _p , z _p ) and unit vectors of x-axis, y-axis and z-axis Becomes Here, l _x , m _x , and n _x are the direction cosines l _y , m _y , and n _y of the copy plane x ′ axis, and the direction cosines l _z , m _z , and n _z of the copy plane y ′ axis are , The direction cosine of the z ′ axis of the copy plane. Next, coordinate conversion from the copy coordinate system to the robot-specific coordinate system at the time of copying the registered figure is performed by the following equation. Z 'in the direction of the teaching rod when teaching the point
The (z ″) axis direction is determined, and at the same time, the nozzle attitude information (α, β) is determined, that is, a plane including a point and perpendicular to the z ′ (z ″) axis, that is, x′−y ′ (x ″).
−y ″) plane is determined. That is, from the posture information (α, β) at the point teaching,
The direction cosine in the z '(z ") axis direction is as follows. Here, as shown in FIG. 10, U is a vector in the direction of the teaching rod, and when the intersection angle between the α axis and the β axis is 45 °, It is. Where n ₁ , n ₂ and n ₃ are And Next, since the direction of the reference axis L 'is determined by the teaching of the points, the x' (x ") axis direction and the y '(y") axis direction are determined. That is, the direction cosine in the + y ′ (y ″) axis direction is obtained by the following equation. Therefore, here, in this way, Is obtained, the direction cosine in the + x ′ (x ″) axis direction is
It is obtained by the following equation. Therefore, by substituting these formulas [II], [III], and [IV] into the above formula [I], the registered graphic data is temporarily moved to the copy coordinate system by rotation and translation as shown in FIG. The position information (X, Y, Z, α, β) is obtained by conversion into a teaching coordinate system, that is, a robot-specific coordinate system. Also, in the case of an arbitrary shape consisting of a free curve, in a case where the nozzle 4 is copied in a fixed posture with respect to the copy plane, graphic data is registered by, for example, teaching, and similar to the above-described graphic pattern, The robot posture at the time of teaching at the first point during copying is directly obtained as posture information (α, β), the reference axis direction is taught by teaching at the second point, and the position information ( X, Y, Z) can be easily obtained. Further, according to such a teaching method, for example, as shown in FIG. 11, the same figure can be continuously copied on a plurality of arbitrary surfaces on the three-dimensional work W. In this case, as shown in FIG. 12, while designating graphic data and teaching one point or two points at each copy position, and creating them in a continuous machining program (FIG. 13), the fourteenth processing is performed. Robot position information for continuous processing as shown in the figure can be obtained. Similarly, by incorporating different types of graphic data into the machining program in the same manner, it is possible to continuously copy different types of graphics on a plurality of arbitrary surfaces on the three-dimensional work W. Also in this case, the teaching does not need to teach all the points on each figure trajectory.
Since teaching can be performed by two points or two points, teaching time can be short and a machining program can be easily created in a very short time. Furthermore, by registering this machining program in the hard disk, the same copying work of the same shape workpiece can be easily and repeatedly repeated only by specifying the program, and the production efficiency is greatly improved. (Effects of the Invention) As described above, according to the present invention, a plurality of types of graphic data are registered in advance, and the registered graphic data is selected and only two points are taught on an arbitrary surface to be copied.
In other words, the coordinates of the first point serving as the reference point of the graphic data and the inclination of this surface are taught by the posture of the teaching head, and the second point in the reference axis direction of the graphic that determines the direction of the graphic is selected. The copy position information, copy direction information, and copy plane information of the copied graphic data can be simultaneously taught, and the copy coordinate system is determined. Position information and orientation information of the coordinate system can be easily obtained. Therefore, in the teaching of two points, the position information and the posture information are copied in the same manner as in the teaching at all the points of the selected graphic information. This eliminates the need for teaching at the points (1), (3), and simplifies the teaching operation, thereby greatly reducing the teaching time. Further, as compared with the teaching of all points, the teaching error has less influence on the processing, and if the copy coordinate system is determined, the figure locus as it is the registered figure data is copied to the designated position, so that the processing shape accuracy is improved. In particular, repetitive copying of the same figure or multiple copying of various figures on an arbitrary surface on a three-dimensional work can be performed in a short time and with high accuracy, and the production efficiency of the robot is greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a control system of a laser processing machine according to the method of the present invention, FIG. 2 is a view showing a laser processing head and a robot-specific coordinate system, and FIG. FIG. 4 is a diagram showing a teaching method of various graphic patterns, FIG. 5 is a diagram showing a teaching trajectory, FIG. 6 is a diagram showing a robot trajectory based on converted position information, FIG. 7 to FIG. 10 is an explanatory diagram for coordinate transformation calculation, FIG. 11 is a diagram showing a plurality of copying examples, FIG. 12 is a diagram showing the teaching trajectory, FIG. 13 is a diagram showing the same machining program, FIG.
FIG. 14 is a diagram showing a robot trajectory based on the position information after the conversion. X, Y, Z: orthogonal 3 constituting the robot-specific coordinate system
Axes, x ', y', z '... orthogonal 3 constituting a copy coordinate system
Axis, α, β… Rotation 2 that constitutes the robot-specific coordinate system
Axis, P ₁ ... Reference point, L... Reference axis, P ′ ₁ , P ′ _2.
Teaching point.

Claims (1)

(57) [Claims] In an industrial robot in which five axes are simultaneously controlled by three orthogonal axes and two rotation axes in the robot-specific coordinate system, a plurality of types of graphic data are registered in advance, and an arbitrary tertiary of the selected graphic data is selected from the graphic data. When copying and teaching on the original plane, teaching is performed based on the coordinates of the first point corresponding to the reference point of the graphic data selected on the surface to be copied and the posture of the teaching head with the inclination of this surface,
A teaching method in an industrial robot, wherein the teaching data is copied on a three-dimensional plane by teaching the coordinates of a second point that determines the direction of the drawing data.