JPH06339850A - Polishing surface instruction method in polishing device - Google Patents

Abstract

PURPOSE:To reduce necessary storage capacity by reducing the number of instruction points at instruction work time as well as to carry out polishing work even on a polishing surface of a wide area only by one time polishing surface instruction. CONSTITUTION:Two directions are defined to define a polishing surface of a metal mold, and first of all, among them, positions of two or more points on two or more curved lines extending at optional intervals in one direction X and in the other direction Y are instructed, and approximate curved lines L1-Lm in this direction Y are obtained by using an interpolative polynominal of a high order, and an approximate curved line Lx in the X direction is found according to data on the respective approximate curved line groups L1-Lm obtained here by using an interpolative polynominal of a high order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a polishing device,
The present invention relates to a polishing surface teaching method for teaching an arbitrary three-dimensional curved surface that is a polishing surface.

[0002]

2. Description of the Related Art When polishing a die or the like using an industrial robot, it is necessary to always polish a polished surface from a vertical direction because a good finish is required. In order to reliably achieve it, the polishing surface must be taught in advance. As a method of teaching an arbitrary three-dimensional curved surface as a polishing surface, for example, in Japanese Patent Laid-Open No. 2-139166, a mold surface is divided into segments, and a plurality of points for boundary setting are set for each segment. In addition to teaching, set the minimum number of points required to determine the shape of each segment or set the parameters required to determine the shape of each segment. There is disclosed a method of calculating the shape of a segment to be operated, and operating the robot arm to press the polishing tool perpendicularly to the mold surface based on the calculated segment shape, preset polishing conditions and set boundaries. There is. However, in such a method, it is necessary to teach the entire range of the curved surface finely or to store the pattern of the curved surface by the copying method.

Further, when performing a polishing operation in a polishing apparatus, a robot command value (position and orientation) is obtained at each point on the polishing surface, which is divided at regular intervals on the polishing path, and the robot is operated by the command value. Although the polishing work is performed by moving the polishing surface, especially when the polishing surface is a free-form surface, it is necessary to make intervals between the polishing paths smaller. When the polishing path is divided into small parts, the number of command values of the robot increases, which requires a huge memory capacity, and the polishing surface must be divided into several areas for teaching.

Further, conventionally, when a brushing range on an arbitrary three-dimensional curved surface is designated, a straight line interpolated between teaching points for designating the brushing range is designated as the brushing range. If the range is specified, there is a problem in that the polishing range cannot be accurately specified, and in order to correctly specify the polishing range, a large number of teaching points are required and the teaching work takes time. According to the conventional method, in order to determine the robot's wrist posture with respect to a free-form surface, a method of teaching the entire area of the curved surface in a fine and straight manner is used, but it takes time to teach and the polishing surface However, there was a problem that it was difficult to teach them directly.

[0005]

The first problem to be solved by the present invention is to teach an arbitrary three-dimensional curved surface,
It is an object of the present invention to provide a polished surface teaching method capable of significantly reducing the number of teaching points. The second problem is that even in the case of a large area of the polished surface, do not divide the polished surface into small pieces.
It is to do the polishing work with less teaching. A third object is to provide a method capable of accurately designating a polishing range on an arbitrary three-dimensional curved surface with a few teaching points. A fourth object is to provide a teaching method that can be easily performed in a short time by not having to adjust the posture of the wrist of the robot to be perpendicular to the surface when teaching a free-form surface. The fifth problem is to judge whether the teaching is appropriate and
It is an object of the present invention to provide a polished surface teaching method that can easily determine where on the teaching surface the correction is required if the teaching is inappropriate.

[0006]

Means for solving the first problem is to define two directions for defining a polishing surface of a mold, and first, in one direction X of them, at an arbitrary interval. Teach two or more points on two or more curves extending in one direction Y, obtain an approximate curve in this direction Y using a high-order interpolation polynomial, and obtain each approximate curve group obtained here. It is to obtain an approximate curve in the X direction by using a high-order interpolation polynomial based on the data of. The means for solving the second problem is a method of creating a data group of the position and orientation of the robot at each point divided on the path of the designated polishing pattern at regular intervals based on the data of the taught polishing surface. If the change in the robot posture at three consecutive points is smaller than the value specified in advance, the three points are considered to be on a straight line, and the second point data is used as the robot data for creating the path of the pattern. Delete from the group and repeat for all possible 3 consecutive points.
Means for solving the third problem is to define a scribing area of an arbitrary shape by interpolating between teaching points using a higher-order interpolation polynomial based on three or more teaching points for designating a polishing range. It is to be. In this case, consider a vector that projects a vector connecting adjacent teaching points onto a plane that defines the polishing surface, and consider the point where the angle formed by the adjacent vectors is greater than a preset value as a discontinuous point, and discontinue. The brushing range is specified by interpolating each teaching point group divided by points by a high-order interpolation polynomial. The means for solving the fourth problem is to teach a line on the basis of a plurality of lines extending in one direction on a brush surface, and teaching points at appropriate intervals on each line. Interpolation between points and between teaching lines is performed by a high-order interpolation polynomial to obtain an approximate curved surface of the brushed surface, and the robot's wrist posture at a certain point on the brushed surface is determined based on the coordinate values of points in the vicinity thereof. It is to be. The means for solving the fifth problem is the means for solving the first problem, wherein the robot is actually operated on the approximate curved surface obtained by interpolating the teaching point group, and at that time, the robot is placed on the tip of the wrist of the robot. Equipped with a differential transformer for measuring the amount of force deviation, the amount of deviation between the differential transformer data obtained on each of the above interpolation points and the preset differential transformer data is preset. Is stored, the robot is operated to the stored point, the point is corrected by correcting or newly adding the point, and the operation is repeated.

[0007]

With the first means, an arbitrary three-dimensional curved surface is taught by teaching the representative points of the brush surface, and the teaching work is simplified with a small number of teaching points. By the second means, it is possible to create the polishing path even in the case of only a large area of the polishing surface without dividing the polishing surface into fine sections. By the third means, the polishing range can be specified at less teaching points. By the fourth means, it is not necessary to adjust the posture of the wrist of the robot to be perpendicular to the polishing surface when teaching the polishing surface. By the fifth means, the approximate surface obtained by interpolating the teaching points can be confirmed. Further, it becomes easy to correct and add the teaching point.

[0008]

EXAMPLES The present invention will be specifically described below with reference to examples. FIG. 15 is a system block diagram showing the configuration of a scouring device for carrying out the present invention. In the figure, 1 is a robot control panel, 2 is a robot, 3 is a mold having a brushing surface on the upper side, 4 is a CRT monitor, 5 is a teaching box for teaching work, 6 is a differential transformer, and 7 is brushing work. It is an electric tool for doing.

FIG. 1 is a flow chart showing an embodiment of a polishing surface teaching method of the present invention. In step 101, two directions (X and Y directions) for defining a polishing surface are determined, and in step 102, a step is performed. One of the directions defined in 101 (Y direction) is selected. In step 103, a curve on the polishing surface extending in the Y direction is assumed, and two or more points are taught on this curve. In step 104, this is performed at arbitrary intervals in the X direction to teach a plurality of curves. In step 105, the taught line is the Lagrange's interpolation polynomial Z = Z ₁ N ₁ (y ₁ ) + Z ₂ N ₂ (y ₂ ) + ... + Z
_{L NL} (y _L )

[Equation 1] To obtain approximate curves L _{1 to} L _m as shown in FIG. In step 106, Y is calculated on the approximated curves L _{1 to} L _m.
= Points P _{1a to} P _ma that satisfy Y _a are obtained. In step 107, the points P _{1a to} P _ma obtained in step 106 are interpolated using a Lagrange's interpolation polynomial to obtain an approximate curve L _X in the X direction. FIG. 2 shows the obtained approximation curve L _X.

Next, a description will be given of an embodiment of a method for performing a polishing operation with a small amount of teaching without dividing the polishing surface into fine sections even on a polishing surface having a wide area. FIG. 3 is a flow chart showing an embodiment of the present method, and FIG. 4 is an explanatory diagram of a brushing path. In step 201, the polishing surface is taught, and in step 202, the polishing start point, turning point, and end point of each polishing path are obtained. In step 203, N, which is the number of the polishing path, is determined, and in step 204, the N-th polishing path is divided at regular intervals, and the command values (position and orientation) of the robot at each point divided in step 205 are obtained.
In steps 206 and 207, the changes in the robot wrist posture at three consecutive points on the Nth scratching path are examined, and if the rate of change is smaller than a preset value, it is considered that the three points are on a straight line. The second point data is deleted from the robot command value group. All contiguous 3 to consider this
Do about the points. In steps 208 and 209, the next polishing path is selected, and steps 204 to 207 are repeated until the selected polishing path is the final polishing path.
The set value to be compared with the change in the robot wrist posture can be determined by the size of the polishing tool to be used and the allowable amount of copying when the polishing tool has a copying mechanism.
FIG. 5 shows the robot command value on the polishing path obtained by the conventional method, and FIG. 6 shows the robot command value obtained by the method of the present invention. In these figures,
P _{1 to} P _N indicate robot command values obtained on the brushed surface.

Next, a method for accurately designating a polishing range on an arbitrary three-dimensional curved surface with a few teaching points will be described. In FIG. 7, in step 301, the points P _{1 to} P _n are taught so as to go around the polishing region at appropriate intervals. In step 302, the vector V ₁ was projected onto the XY plane to define the vector V _m the polishing surface from a certain teaching point P _m toward the next teaching point P _{m + 1} according to the teachings order ~V
Consider _n-1 (see Figure 8). The angle formed between adjacent vectors at a certain teaching point is checked, and if this is within a certain preset angle, it is considered that the teaching line is continuous at that teaching point (only the face A in FIG. 9A). , If it is larger than a preset angle, it is considered to be discontinuous (only the face B of FIG. 9B). In step 303, one discontinuity point to the next discontinuity point is regarded as one continuous curve, and the brushed area is defined by one or more continuous curves. In Step 304, Step 30
The points on each curve defined in 3 are interpolated according to the Lagrange's interpolation polynomial to obtain an approximate curve that defines a region.

Next, a teaching method for teaching a brushed surface, which can be easily performed in a short time without adjusting the posture of the wrist of the robot to be perpendicular to the brushed surface, will be described. 10 to 11 are flowcharts thereof, and in step 401, two directions (X
And Y direction), and in step 402, one of the directions defined in step 401 (Y direction) is selected. In step 403, a line extending in the Y direction is assumed on the brushed surface, and 2 lines are appropriately spaced on this line.
Teach more points. In step 404, this is X
A plurality of lines are taught by performing an arbitrary interval in the direction. In step 405, the taught line is interpolated by a Lagrange interpolation polynomial to obtain approximate curves L _{1 to} L _m (see FIG. 2).
reference). In step 406, the approximate curves L _{1 to} L _m
Find points P _{1a to} P _ma where Y = Y _a above, and step 40
At 7, the points P _{1a to} P _ma are interpolated using the Lagrange's interpolation polynomial to obtain an approximate curve L _x in the X direction. Step 4
In step 08, X = X _a on the approximation curve obtained in step 407.
Then, the Z coordinate of the point P is obtained by interpolating the obtained point with a Lagrange's interpolation polynomial. Step 4
09, points P ₁ and P ₂ apart from the point P in the X direction by −d and + d, and points P ₃ and P ₄ from points P apart from the point P in the Y direction by −d and + d.
Then, the Z coordinate values of the points P _{1 to} P ₄ are calculated in the same manner as the point P (see FIG. 12). In step 410, a vector a going from the point P ₁ to the point P ₂ and a vector b going from the point P ₃ to P ₄ are calculated (see FIG. 12). In step 411,
The unit normal vector of the vectors a and b is obtained from the outer product of the vectors a and b, and this is set as the unit normal vector at the point P on the polishing surface. In step 412, the unit normal vector at the point P and the coordinate value of the point P are converted into robot control data.

Next, it is possible to easily confirm whether the teaching result of the polished surface is appropriate, and if the teaching result is inappropriate, it is possible to easily determine where on the teaching surface the correction-required portion is. The polished surface teaching method will be described with reference to the flowchart of the embodiment shown in FIG. Step 501
In, a teaching point group that forms a curved line is taught on the polished surface in a row at arbitrary intervals. In step 502, the teaching points on each curve are interpolated by Lagrange's interpolation polynomials to obtain a group of approximate curves L _{1 to} L _n on the polishing surface, and further, step 503. Based on the data obtained from each of the approximate curves, the curves are interpolated by a Lagrange's interpolation polynomial to obtain an approximate curve F of the brushed surface (see FIG. 14A). In step 504, the position and orientation of the robot to move on the approximate curved surface obtained in step 503 is obtained. At step 505, based on the data obtained at step 504, as shown in FIG. 15, the robot 2 equipped with the differential transformer 6 at the tip of the wrist is operated on the scratching surface of the mold 3 only, and at each interpolation point. The point where the deviation amount between the data of the differential transformer 6 obtained in step 1 and the preset differential transformer data is larger than the preset deviation amount is stored. In step 506, the teaching point data is updated by moving the robot 2 to the point stored in step 505 and correcting or newly adding the point (see point P _m 'in FIG. 14B). In step 507, it is determined whether or not the teaching point data has been updated. When the teaching point data is updated, steps 502-506 are repeated, and when the data is not updated, the teaching of the polished surface is finished.

[0014]

As described above, the present invention has the following effects. By reducing the robot command value during teaching work, it is possible to reduce the required storage capacity.
Even on a large area, the polishing work can be done by teaching the polishing surface once. By reducing the robot command value when creating the brush path, the required storage capacity can be reduced, and the brush path can be created by teaching only the scratch surface once even on the scratch surface of a wide area. By approximating the teaching point group designating the polishing range by a high-order interpolation polynomial, it is possible to specify the range with higher accuracy from a few teaching points. It is possible to easily and quickly teach a carved face without considering the wrist posture of the robot. You can check the approximate surface obtained by interpolating the teaching points.
If the teaching is inappropriate, the teaching point can be easily corrected or added, and accurate teaching can be performed in a short time.

[Brief description of drawings]

FIG. 1 is a flow chart of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a polishing surface teaching method in the present embodiment.

FIG. 3 is a flowchart of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a method of creating a polish route in the present embodiment.

FIG. 5 is an explanatory diagram in which a command value on a polishing path is obtained by a conventional method.

FIG. 6 is an explanatory diagram of a robot path obtained by the method of this embodiment.

FIG. 7 is a flowchart of a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of the present embodiment.

FIG. 9 is an explanatory diagram of regions in this embodiment.

FIG. 10 is a flow chart of the fourth embodiment of the present invention. -It is the first of the chart.

FIG. 11 is a second part of the flowchart of the fourth embodiment of the present invention.

FIG. 12 is an explanatory diagram of the present embodiment.

FIG. 13 is a flowchart of the fifth embodiment of the present invention.

FIG. 14 is an explanatory diagram of the present embodiment.

FIG. 15 is a system block diagram of the present invention.

[Explanation of symbols]

1 robot control panel, 2 robots, 3 molds, 4 C
RT monitor, 5 teaching boxes, 6 differential transformers, 7 electric tools

Claims (6)

[Claims] 1. Defining two directions for defining a polishing surface of a mold, and first, in one direction X of them, at an arbitrary interval,
Teach two or more positions on two or more curves extending in the other direction Y, and use a higher-order interpolation polynomial to determine this direction Y.
And the approximate curve in the X direction is obtained by using a high-order interpolation polynomial based on the data of each approximate curve group obtained here. Method. 2. Based on the data on the taught polished surface,
In the method of creating a data group of the position and orientation of the robot at each point that divides the path of the designated polishing pattern at regular intervals, if the change in the orientation of the robot at three consecutive points is smaller than the value specified in advance , These 3 points are regarded as being on a straight line, the data of the 2nd point are deleted from the data group of the robot for creating the path of the pattern, and this is repeated for all conceivable 3 points. Method for creating polishing path in polishing device. 3. A scribed area of any shape is defined by interpolating between the taught points using a higher-order interpolation polynomial based on three or more taught points for designating the scouring range. Polishing range designation method. 4. A method according to claim 3, wherein a vector connecting the adjacent teaching points is projected on a plane defining a polishing surface, and an angle formed by the adjacent vectors is larger than a preset value. A polishing range specifying method characterized in that points are regarded as discontinuous points and each teaching point group delimited by the discontinuous points is interpolated by a high-order interpolation polynomial. 5. A plurality of lines extending in one direction are assumed on the polishing surface, points are taught at appropriate intervals on each line, and the teaching points on the lines and the teaching lines are taught based on the teaching points. Is obtained by performing an interpolation with a high-order interpolation polynomial to obtain an approximate curved surface of the brushed surface, and the wrist posture of the robot at a point on the brushed surface is determined based on the coordinate values of points in the vicinity thereof. A wrist posture control method for a robot in a polishing device. 6. The method according to claim 1, wherein the robot is actually operated on an approximate curved surface obtained by interpolating the teaching point group, and at that time, the amount of force deviation is measured at the tip of the wrist of the robot. Equipped with a differential transformer of, and stores the point where the deviation amount between the data of the differential transformer obtained on each of the above interpolation points and the preset differential transformer data becomes larger than the preset value. A method for teaching a polishing surface in a polishing device, comprising: operating a robot to the stored point, correcting or newly adding the point to correct the teaching point group, and repeating the operation.