JPH0957598A - Numerical controller and its working locus control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve finishing conditions by providing a locus operation means which performs acceleration/deceleration operation after distributing the pulses to respective shafts to operate smoothly without stopping according to unsmooth shapes obtained from the outside program of working locus. SOLUTION: A shape error is compensated by connecting across correction vectors of tool diameter correction blocks B1, B2, which have different correction quantities and positioned in the front and the rear each other, by a linear block, and by using a tool diameter correction mechanism which can change the correction quantity according to a tool diameter correction block in a working cycle. Namely, when the lengths of the correction vectors V1, V2 are different, a different level part is connected by a linear vector V3, a collinear line of the correction vectors V1, V2. The shape which is obtained by an outside program of a formed working locus and is not always a smooth shape is smoothly corrected by pulse distribution to respective shafts and acceleration/ deceleration operation afterward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical controller suitable for use in machining control of a sink welding bead removing device using a polishing belt, and a machining trajectory control system executable by this controller.

[0002]

2. Description of the Related Art Seam welding or TIG welding is used for welding a sink and a top plate to a sink. In this type of machining, the original machining shape is a figure that is connected smoothly by a straight line and multiple arcs, but the shape of the welded part may differ from the work drawing dimensions due to welding conditions and welding methods. Can be large. The welding bead that causes such an error is removed by the polishing belt head using the welding bead removing device using the polishing belt.

In such welding bead removal processing, the movement of the polishing belt head is controlled by using a numerical controller (hereinafter simply referred to as NC), and it is finished when the relative speed of the belt head and the work is kept constant. It is said to be in good condition. However, if the end point coordinates etc. are easily changed in order to make the processing trajectory follow the shape error of the weld bead,
An angle is generated at the connection part of the moving block, and the feed rate fluctuates at that part, and the finish tends to be poor. Therefore, conventionally, the calculation for obtaining the end point and the center coordinate of the arc command is performed so that the connection angle between the moving blocks approaches 0 degree, but such work is troublesome. In addition, there are many teaching points in the teaching work found in robots and the like, which causes a problem that a lot of time is spent in creating a program.

In view of such conventional problems, the present invention has been made.
By simply inputting the drawing dimensions according to the pattern shape of the processed work, it is expanded into NC program data of the work shape,
Rather than changing the shape data itself as in the past, changing the trajectory shape by the correction function makes it easier to create programs, making program creation and modification easier than before, and making preparations such as trial machining and adjustments. It is an object of the present invention to provide a numerical control device that can improve the finishing condition by shortening the time required for finishing and moving a shape that is not always smooth while suppressing the speed fluctuation as much as possible, and a machining trajectory control method thereof. To do.

[0005]

In order to achieve the above object, a numerical controller according to claim 1 of the present invention can control two or more orthogonal axes and a turning axis, and can control a trajectory such as a straight line or an arc. In the numerical control device capable of calculating the coordinates according to the shape of the work pattern and developing it in the NC program, the correction vector at the end of the tool diameter correction block on the front side and the rear side of the tool diameter correction block having different and different correction amounts Tool diameter correcting means for connecting the correction vectors at the starting end of the tool diameter correcting block with one straight line block to change the correction amount for each tool diameter correcting block, and these N
Acceleration / deceleration after pulse distribution to each of the above-mentioned axes in order to operate smoothly without stopping according to the shape that is not necessarily smooth obtained from the contour program of the machining trajectory generated by the expansion means for C program and the tool radius correction means It is characterized by having a locus calculation means for performing a calculation.

In the numerical controller according to the second aspect of the present invention, the linear block connecting the correction vectors has a correction vector at the end of the front tool radius correction block and a correction vector at the start end of the rear tool radius correction block. When the tangent angles are the same, the end point of the correction vector at the end of the tool radius correction block on the front side and the end point of the correction vector at the start of the tool radius correction block on the rear side are connected to form a collinear line with both correction vectors. It consists of a straight line vector, the tangent angle is not equal between the correction vector at the end of the tool radius correction block on the front side and the correction vector at the start end of the tool radius correction block on the rear side,
And when both correction vectors are directed to the outside of the work pattern shape, a straight line vector connecting the end point of the correction vector at the end of the front side tool diameter correction block and the end point of the correction vector at the start side of the rear side tool diameter correction block It is characterized by consisting of.

In the numerical controller according to a third aspect of the present invention, the tool radius correcting means has a tangent line between the correction vector at the end of the front tool radius correction block and the correction vector at the start end of the rear tool radius correction block. When the angles are not equal and both correction vectors point to the inside of the work pattern shape,
When both the tool radius correction blocks have an intersection, the two tool radius correction blocks are connected at the intersection.

In order to achieve the above object, the machining locus control method of the numerical controller according to claim 4 of the present invention can control two or more orthogonal axes and a turning axis, and can control loci such as straight lines and arcs. Is a machining trajectory control method that can be executed in a numerical control device that can calculate the coordinates according to the work pattern shape, develops it in the NC program, and corrects the tool radius on the front side of the tool radius correction block with different and different correction amounts. Connect the correction vector at the end of the block and the correction vector at the start of the tool radius correction block on the rear side with one straight line block to change the correction amount for each tool radius correction block.
It is characterized in that pulses are distributed to each of the above-mentioned axes according to a shape that is not necessarily smooth obtained from the contour program of the generated machining path, and thereafter acceleration / deceleration calculation is performed to enable smooth operation without stopping.

In a machining trajectory control system of a numerical controller according to a fifth aspect of the present invention, the straight line block connecting the correction vectors has a correction vector at the end of the tool diameter correction block on the front side and a start end of the tool diameter correction block on the rear side. If the tangent angle is the same as that of the correction vector of, the end point of the correction vector at the end of the tool diameter correction block on the front side and the end point of the correction vector at the start of the tool diameter correction block on the rear side are connected to both correction vectors. , And the correction vector at the end of the tool radius compensation block on the front side and the correction vector at the beginning of the tool radius compensation block on the rear side are not equal and both compensation vectors are When facing the outside of the work pattern shape, the end point of the correction vector at the end of the tool diameter correction block on the front side and the end of the tool diameter correction block on the rear side Characterized by comprising the linear vector connecting the end point of the correction vector end.

In the machining trajectory control method of the numerical controller according to the sixth aspect, the tangent angle between the correction vector at the end of the front tool radius correction block and the correction vector at the start end of the rear tool radius correction block is When the corrected trajectories have intersections when they are not equal and both correction vectors point toward the inside of the work pattern shape, the two tool diameter correction blocks are connected at the intersections.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, it is assumed that the NC of the present embodiment can control two or more orthogonal axes and a turning axis, and can control a trajectory such as a straight line and a circular arc. However, these functions are well known as a multi-axis control NC, and therefore the description will not be given. Omit it.

Further, the NC of this embodiment has a function of calculating coordinates according to the shape of the work pattern and developing it into an NC program, that is, a CAM function. Specifically, all workpieces have dimensions on the drawing (for example, width W, height H, corner radii R1 to R3, etc. as shown in FIG. 1), and simultaneous equations are set up from the necessary data on the drawing. It has a function that can be expanded to NC program data for describing the shape of the workpiece if calculated.

Data expansion by the CAM function described above is
Specifically, a function called a pattern macro function or the like describes the relationship between the pattern shape and the moving block. That is, by inputting the work drawing dimension, the work block is expanded into a plurality of moving blocks (a set of G codes for linear interpolation and circular interpolation). For example, with respect to the left and right and vertically symmetrical sync figures as shown in FIG. 2, the pattern of the moving block of the quarter of the shape is one pattern figure, that is, straight line-arc-
Considered as a pattern figure consisting of straight lines, width W, height H,
For a work having a corner radius R, the above pattern figure is selected by using the pattern macro function in NC, and the moving direction (clockwise direction CW or counterclockwise direction CC) is selected.
W), width W, height H, and corner radius R are input to automatically expand into a plurality of moving blocks (G codes for linear interpolation and circular interpolation). It should be noted that in the example of FIG. 2, the 1/4 figure consists of three moving blocks.
Expanded to the moving block of.

FIG. 3 is a flowchart for creating and modifying a program based on this function. First, as shown in FIG. 3, a shape pattern is selected, dimension width W, height H, corner radii R1, R2, ... Of the drawing are input, and shape data is automatically generated and programmed (step 1). . In FIG. 3, G codes G91 and G0 by the preparation function (G function) are shown.
1, G02 ... After that, the machining origin is aligned (step 2), and trial machining is performed (step 3).
The finish is judged (step 4), if it is good, the actual machining is started (step 5), and if it is bad, the shape error is corrected (step 6).

In the NC of the present embodiment, the correction of the shape error is performed by connecting the correction vectors having different correction amounts of the preceding and following tool diameter correction blocks with one straight line block, and for each tool diameter correction block in one machining cycle. This is done using the tool radius compensation function, which allows the compensation amount to be changed. To connect the tool radius correction vectors having different correction amounts with one straight line block means to combine the start and end correction vectors of the two front and rear tool radius correction blocks B1 and B2 with one straight line block.

That is, as shown in FIG. 4a, the correction vector V1,
When the vector lengths of V2 are the same, the straight line block is not inserted. However, when the vector lengths of the correction vectors V1 and V2 are different as shown in FIG. 4b, the step portion is collinear with the correction vectors V1 and V2. Connect with a straight line vector V3.

Further, as shown in FIG. 4c, the correction vector V
Even if the directions of 1 and V2 are different, the linear block V3 is inserted. As shown in FIGS. 4c and 4d, when the tangent angle difference is other than 0 degrees, both correction vectors V1 and V2 are directed to the outside of the work pattern shape, and accordingly, the correction vectors V1 and V2.
When correcting to the outside of 2, always insert one linear block. Further, as shown in FIG. 4e, the correction vectors V1 and V
2 is directed to the inside of the work pattern shape, and therefore, when the correction is performed inside the correction vectors V1 and V2, the correction is performed at the intersection K of the tool diameter correction blocks (broken lines) corrected by the correction vectors V1 and V2. In a machining center or the like, this method causes problems such as tool interference and uncut parts, but a belt grinding device such as a bead removing device of a sink does not pose a problem and has an advantage that the calculation is simple.

Note that the (tool diameter) correction vector is, as is well known, for offsetting a programmed figure so that the end face of the tool moves along the figure rather than the center thereof. If the offset is not applied by the correction vector V, the program figure P passes through the center of the tool T, and the tool radius is corrected as shown in FIG. 5B, whereby the end surface of the tool T passes through the program figure P and the desired machining is performed. become able to.

The figure Pa which has been subjected to such a correction, that is, the tool locus figure, follows the outer circumference or the inner circumference of the program figure P of the work having the width W, the height H and the corner radius R.
For example, as shown by the broken line in FIG. 6, the figure has a step due to the difference in the length of the correction vector.

The stepped portion is shown in an enlarged manner in FIG. 7, and the feed speed fluctuates at the stepped portion if left as it is. Therefore, the NC of the present embodiment is configured such that each axis is inserted after the linear block is inserted. It is necessary to make the corrected tool locus figure Pa into a smooth locus Pb by performing pulse distribution on the above, and then performing acceleration / deceleration calculation.

The pulse distribution to each axis and the subsequent acceleration / deceleration calculation will be described. First, pulse distribution will be described. Usually, in order to calculate the target position for each control cycle of each axis when performing continuous trajectory control, the information of the geometrical figure is expressed by a mathematical expression in a parametric expression based on time and distance. For example, with linear interpolation

## EQU1 ## Taking y = 0.5x + 1 and x = 0 → 4 as an example, in the machining program, the start point (0, 1),
The command is given as the end point (4, 3), and the locus becomes as shown in FIG. If the moving distance L is expressed as a parameter, the straight line length δ of the locus is

[Expression 2] δ = √ ((4-0) 2+ (3-1) 2), and therefore the x and y coordinates of the point moved by the distance L are

## EQU3 ## It is expressed as x = 0 + (4-1) L / √20 y = 1 + (3-1) L / √20. When L is a moving distance pulse, x and y correspond to the pulses distributed to each axis. Such calculation itself is called an interpolation operation, and thus distributing pulses to each axis is synonymous with performing an interpolation operation.

In the acceleration / deceleration calculation after the pulse distribution, the above-mentioned pulse distribution data is further multiplied by a predetermined time constant to accelerate or decelerate the moving speed of each axis as shown in FIG. The locus figure immediately after, the solid line is the locus figure after acceleration / deceleration, and the tool locus figure Pa is a smooth locus Pb as shown in FIG. Although the linear velocity in this part is slightly smaller, it is almost the designated velocity. Further, in this method, the shape error increases as the tool feed speed increases, but with a bead removing device or the like, the locus accuracy during machining is about ± 1 mm, which is not a practical problem. 8 and 9, only two orthogonal axes (x axis and y axis) are described, but the present invention is not limited to this.
The same can be done for the pivot axis.

[0023]

The numerical control device and the machining trajectory control method thereof according to the present invention can be applied to an NC program in which coordinates are calculated and developed in accordance with a work pattern shape in a numerical control device capable of controlling two or more orthogonal axes and a turning axis. Then, in the tool radius correction blocks having different and front and back correction amounts, one straight line block is connected between the correction vector at the end of the tool diameter correction block on the front side and the correction vector at the start end of the tool diameter correction block on the rear side. Since it was corrected for each tool radius correction block and the shape that was not always smooth obtained from the contour program of the generated machining path was corrected by pulse distribution to each axis and the subsequent acceleration / deceleration calculation, Program creation and modification is easier than with numerical control devices,
The time required for setup such as trial machining and adjustment can be shortened, and the finishing condition can be improved by moving the tool while suppressing the speed fluctuation as much as possible for a machining program trajectory that is not always smooth. .

[Brief description of drawings]

FIG. 1 is a diagram for explaining a function of expanding necessary data on a work drawing into NC program data for describing a work shape.

FIG. 2 is a diagram showing patterning by a moving block in a quarter portion of a left / right and vertically symmetrical sync figure.

FIG. 3 is a flowchart for creating and modifying an NC program.

FIG. 4 is a diagram showing a non-insertion and insertion form of a tool radius correction vector.

FIG. 5 is a diagram for explaining a tool radius correction vector.

FIG. 6 is a diagram showing a figure having a step due to a difference in length of a tool radius correction vector.

FIG. 7 is an enlarged view showing a stepped portion of the figure of FIG.

FIG. 8 is a diagram showing a locus in a linear interpolation processing program.

FIG. 9 is a diagram showing a trajectory figure immediately after pulse distribution and a trajectory figure after acceleration / deceleration.

[Explanation of symbols]

 B1, B2 Tool radius correction block V, V1, V2 Correction vector V3 Straight line vector forming a straight line block K Crossing point of tool diameter correction block P Program figure Pa Tool path figure after correction Pb Smooth path after acceleration / deceleration calculation T Tool

Claims (6)

[Claims] 1. In a numerical control device capable of controlling two or more orthogonal axes and a turning axis, and controlling a trajectory such as a straight line or an arc, a means for calculating coordinates in accordance with a work pattern shape and developing it in an NC program, and a correction amount. For each tool radius correction block, connect a correction vector at the end of the tool radius correction block on the front side and a correction vector at the start end of the tool diameter compensation block on the back side of different tool radius compensation blocks with one straight line block. The tool diameter correcting means that can change the correction amount, and the machining trajectory generated by the NC program expanding means and the tool diameter correcting means do not necessarily stop in accordance with the non-smooth shape obtained from the outer shape program. A numerical control device having a locus calculation means for performing acceleration / deceleration calculation after pulse distribution to each axis in order to operate smoothly. 2. When the straight line block connecting the correction vectors has the same tangent angle between the correction vector at the end of the front tool radius correction block and the correction vector at the start end of the rear tool radius correction block, , Consisting of a straight line vector connecting the end point of the correction vector at the end of the tool diameter correction block on the front side and the end point of the correction vector at the start of the tool diameter correction block on the rear side to form a collinear line with both correction vectors, When the tangent angle between the correction vector at the end of the tool radius compensation block and the correction vector at the beginning of the tool radius compensation block on the rear side is not equal, and both compensation vectors point out of the work pattern shape, the front side From the straight line vector connecting the end point of the compensation vector at the end of the tool radius compensation block and the end point of the compensation vector at the beginning of the rear side tool radius compensation block Numerical control apparatus according to claim 1, characterized in Rukoto. 3. The tool radius compensating means is such that the tangent angle between the compensation vector at the end of the tool radius compensation block on the front side and the compensation vector at the beginning of the tool radius compensation block on the rear side is not equal, and both compensations are performed. 2. The numerical controller according to claim 1, wherein when the vector is directed to the inside of the work pattern shape, if the two tool radius correction blocks have an intersection, the two tool radius correction blocks are connected at the intersection. 4. A machining locus control method which can be executed by a numerical control device capable of controlling two or more orthogonal axes and a turning axis and capable of controlling a locus such as a straight line and an arc. Coordinates are calculated according to a work pattern shape. One straight line block developed in the NC program, between the correction vector at the end of the tool diameter correction block on the front side and the correction vector at the start end of the tool diameter correction block on the rear side of the tool diameter correction block with different and different correction amounts Connected to each other to change the correction amount for each tool diameter correction block, distribute the pulse to each axis according to the shape that is not necessarily smooth obtained from the contour program of the generated machining trajectory, and then perform acceleration / deceleration calculation and stop. A machining trajectory control method for a numerical control device, which is characterized in that it can be operated smoothly without doing so. 5. When the straight line block connecting the correction vectors has the same tangent angle between the correction vector at the end of the front tool radius correction block and the correction vector at the start end of the rear tool radius correction block, , Consisting of a straight line vector connecting the end point of the correction vector at the end of the tool diameter correction block on the front side and the end point of the correction vector at the start of the tool diameter correction block on the rear side to form a collinear line with both correction vectors, When the tangent angle between the correction vector at the end of the tool radius compensation block and the correction vector at the beginning of the tool radius compensation block on the rear side is not equal, and both compensation vectors point out of the work pattern shape, the front side From the straight line vector connecting the end point of the compensation vector at the end of the tool radius compensation block and the end point of the compensation vector at the beginning of the rear side tool radius compensation block Machining trajectory control apparatus for a numerical control apparatus according to claim 4, characterized in Rukoto. 6. The tangent angle between the correction vector at the end of the tool radius correction block on the front side and the correction vector at the start end of the tool radius correction block on the rear side is not equal, and both correction vectors are of the work pattern shape. When facing inward,
5. The machining trajectory control method for a numerical controller according to claim 4, wherein, when the corrected trajectory has an intersection, the two tool diameter compensation blocks are connected at the intersection.