JP2006227701A - Circular machining command creation device, method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circular machining command creation device, method and program that can implement high precision circular machining. <P>SOLUTION: The circular machining command creation device comprises a division point setting part 11 for setting, on a circular arc defined according to start point coordinates, end point coordinates and a radius given as input information, division points dividing the circular arc into a predetermined number of divisions, and a command creation part for setting position coordinates and a tangential velocity vector for each of the start point, division points and end point to create a circular machining command. The command creation part 12 sets the velocity vector at the end point at zero. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an arc machining command creation device, a method thereof, and a program that can obtain high machining accuracy by a machine tool or the like.

Conventionally, in an NC machine tool as industrial equipment, when processing an object in a circular arc shape, a plurality of passing points are automatically generated on the circular arc, and the adjacent passing points are connected by a straight line, thereby forming an arc. A method of performing circular interpolation by approximating minute line segment data has been adopted.
However, the method of approximating with such minute line segment data has a disadvantage in that since the two adjacent points are connected by a straight line, the operation trajectory becomes a polygonal shape and a smooth machining trajectory cannot be obtained.
Therefore, in recent years, rather than linearly interpolating arcs with minute line data as described above, spline curves, NURBS (None Uniform Rational B-Spline) curves, Bezier curves, clothoid curves Various methods for performing circular interpolation have been proposed (for example, see Japanese Patent Application Laid-Open No. 10-240329).
JP-A-10-240329

  However, in the interpolation method using the above spline curve or the like, if a large error occurs in the end point machining position of the arc, overshoot or the like will occur in order to shift to the machining of the next trajectory starting from this end point. There was a problem that arc processing could not be performed with high accuracy.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an arc machining command creation device, method and program for realizing arc machining with high accuracy.

In order to solve the above problems, the present invention employs the following means.
The present invention provides division point setting means for setting division points for dividing a circular arc by a predetermined number of divisions on an arc specified based on the coordinates of the start point, the coordinates of the end point, and the radius given as input information. And a command creation means for creating a circular arc machining command by setting a position vector and a velocity vector in the tangential direction for each of the start point, the division point, and the end point, and the command creation means includes the command creation means, An arc machining command creation device for setting the velocity vector at an end point to zero is provided.

  According to the above configuration, the dividing point for dividing the arc by a predetermined number of divisions on the arc specified by the coordinates of the starting point, the coordinates of the end point, and the radius given as input information is a dividing point setting unit. Is set by Subsequently, the command creation means sets the position coordinate and the velocity vector in the tangential direction for each of the start point, the division point, and the end point, for example, an arc machining command for controlling a tool for machining the object. Is created. In this case, the command creating means sets the velocity vector at the end point to zero, so that it is possible to reliably stop at the end point (command position) at the end point. Thereby, it is possible to promptly shift to the next shape processing starting from this end point.

  In the arc machining command creation device described above, the command creation means calculates a tangent vector at the end point and a tangent vector at the end point with respect to a next locus starting from the end point, and a change amount of these tangent vectors is equal to or greater than a predetermined value. In this case, the velocity vector in the tangential direction at the end point may be set to zero.

  According to the above configuration, the command creating unit calculates a tangent vector at the end point and calculates a tangent vector at the end point with respect to the next locus starting from the end point. When the amount of change in these tangent vectors is greater than or equal to a predetermined value, the tangential velocity vector at the end point is set to zero. As a result, for example, when the tangent vector changes rapidly, it is possible to stop the machining at the end point and then shift to the next shape machining. The processing accuracy can be improved without causing any problems.

  In the circular arc machining command creation device described above, the command creation means may set the same value to the velocity vector in the tangential direction at each of the start point and the division point.

  According to the above configuration, the tangential velocity vector at each of the start point and the dividing point is set to the same value, so that the circular arc machining can be performed while keeping the tangential velocity constant. This makes it possible to create a smooth processed surface.

  The present invention provides a machine tool for controlling a tool or a workpiece based on an arc machining command created by the arc machining command creation device described above.

  According to the above configuration, since the tool or workpiece is controlled based on the arc machining command created by the arc machining command creation device, the machining is surely stopped at the end point of the arc, and the next shape starting from this end point It becomes possible to shift to processing promptly.

  The present invention is a division point setting for setting division points for dividing the arc by a predetermined number of divisions on the arc specified based on the coordinates of the start point, end point coordinates, and the radius given as input information. A command creation process for creating a circular arc machining command by setting a position vector and a velocity vector in a tangential direction for each of the start point, each of the division points, and the end point, and the command creation process includes: An arc machining command generation method for setting the velocity vector at the end point to zero is provided.

  The present invention is a division point setting for setting division points for dividing the arc by a predetermined number of divisions on the arc specified based on the coordinates of the start point, end point coordinates, and the radius given as input information. Arc processing command for causing a computer to execute processing and command creation processing for creating an arc machining command by setting a position coordinate and a velocity vector in a tangential direction for each of the start point, the division point, and the end point An arc machining command creation program, which is a creation program, wherein the velocity vector at the end point is set to zero in the command creation process.

  According to the arc machining command creation device, method and program thereof of the present invention, there is an effect that arc machining can be realized with high accuracy.

Hereinafter, an embodiment of an arc machining command creation device according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing the configuration of an arc machining command creation device according to an embodiment of the present invention. The arc machining command creation device according to the present embodiment creates an arc machining command for controlling the movement of a tool or a workpiece when machining an object in an arc shape by a machine tool, for example. It is given to machine tools.

As shown in FIG. 1, such an arc machining command creation device is configured to include a division point setting unit (division point setting unit) 11 and a command creation unit (command creation unit) 12.
The dividing point setting unit 11 is specified based on the coordinates of the start point, the coordinates of the end point, the direction of the arc connecting the start point and the end point (for example, counterclockwise or clockwise) and the radius given as input information. A division point for dividing the arc by a predetermined number of divisions is set on the arc, and the set position coordinates, start point coordinates, and end point coordinates are output.
The command creation unit 12 creates a circular arc machining command by setting a velocity vector in the tangential direction in the coordinates of the start point, the coordinates of the end point, and the position coordinates of each division point input from the division point setting unit 11.

The above-mentioned arc processing command creation device having such a configuration is, for example, a CPU (Central Processing Unit), ROM (Read
The computer system includes only memory (RAM), random access memory (RAM), and the like. A series of processing steps for realizing the various functions of the dividing point setting unit 11 and the command generation unit 12 is recorded in a ROM or the like in the form of a program. By executing the processing / calculation processing, various functions described later are realized.

Hereinafter, various functions realized by the circular arc machining command creating apparatus according to the present embodiment will be specifically described with reference to FIGS.
First, as shown in FIG. 2, the division point setting unit 11 (see FIG. 1) receives as input information the coordinates (X1, Z1) of the start point P1, the coordinates (Xn, Zn) of the end point Pn, the start point P1, and the end point Pn. When the direction of the arc connecting the two (for example, counterclockwise or clockwise) and the radius R are input, the dividing point setting unit 11 adds the coordinates (X1, Z1) of the start point P1 to the XZ coordinates. An arc C having a radius R and passing through the coordinates (Xn, Zn) of the end point Pn is created, and the coordinates (X0, Z0) of the center P0 of the arc C are calculated (step SP1 in FIG. 3).

Subsequently, division points P2 to Pn−1 for dividing the created arc C by a predetermined number of divisions are set on the arc C (step SP2 in FIG. 3).
Here, the number of division points can be determined by time division, for example. As an example, although depending on the required processing accuracy, one division point is set for a processing time of several tens of msec (for example, 20 to 50 msec). In this case, the number of divisions varies depending on the moving distance and speed. Further, the number of division points may be set according to the length of the arc instead of the time division as described above.
When the division points P2 to Pn-1 are set in this way, the division point setting unit 11 sends the coordinates of the set division points P2 to Pn-1 and the coordinates of the start point P1 and the end point Pn to the command creation unit 12. Output.

When the above information is input from the dividing point setting unit 11, the command creating unit 12 creates an arc machining command based on the coordinate information (step SP3 in FIG. 3).
Here, the arc processing command will be described with reference to FIG. As shown in FIG. 4, the circular arc machining command is used for machining from the start point P1, the end point Pn, and the division points P2 to Pn-1 to the coordinates (X, Z) and the next point adjacent to that point. A required time T (hereinafter referred to as “time”) and a tangential speed Vtan at that point are set. At this time, the command creation unit 12 sets the tangential speed Vtan at the start point P1 and the division points P2 to Pn-1 to the same value, and sets the tangential speed Vtan at the end point Pn to zero.

  Further, for the starting point P1 and each of the dividing points P2 to Pn-1, the tangential speed Vtan is divided into an X component and a Z component, and the speed in each component is set as information of one of the arc processing commands. To do. As a result, for example, the X component at the start point P1 is set to the speed Vx1, and the speed of the Z component is set to Vz1.

In this way, when the command creation unit 12 creates an arc machining command in which the speeds related to the position coordinates, time, X component, and Z component are set for each point, this command is output.
Thereby, the circular arc machining command created by the command creating unit 12 is sent to, for example, a machine tool control device and stored in an internal storage device or the like. And the control apparatus of a machine tool can implement | achieve highly accurate circular arc machining by moving a tool based on this circular arc machining command.

As described above, according to the arc machining command creation device according to the present embodiment, in the arc machining command created by the command creation unit 12, the velocity vector at the end point Pn is set to zero. The workpiece can be stopped. Thereby, it is possible to promptly shift to the next shape processing starting from the end point P0.
That is, as shown in FIG. 5, when processing a new shape starting from the end point Pn, the processing is stopped at the end point Pn, thereby avoiding the occurrence of overshoot as shown by the broken line in FIG. It becomes possible to do. As a result, it is possible to realize arc machining with high accuracy, and it is possible to quickly shift to the next shape machining.
Further, according to the arc machining command creation device according to the present embodiment, the command creation unit 12 creates the arc machining command so that the tangential speed at each point is constant, so the machining speed in the tangential direction is constant. It is possible to process the workpiece in an arc shape from the start point to the end point. This makes it possible to create a smooth processed surface.

In the above-described embodiment, the speed at the end point Pn is always set to zero regardless of the shape of the next locus newly starting from the end point Pn. However, the present invention is not limited to this example. The speed in the tangential direction at the end point Pn may be set.
For example, when setting the speed at the end point Pn, the command creation unit 12 first sets the tangent vector Pt1 at the end point Pn and the tangent vector Pt2 at the end point Pn with respect to the next locus L starting from the end point Pn, as shown in FIG. Is calculated.
Subsequently, when the amount of change of the tangent vectors Pt1 and Pt2, for example, the angle θ between Pt1 and Pt2 is equal to or greater than a predetermined value (for example, θmax), the velocity vector in the tangential direction at the end point Pn is zero. Set to.
For example, when the tangent vectors Pt1 and Pt2 are in a substantially parallel state, that is, when the θ is as close to zero as possible, the tangential velocity at the end point Pn is not set to zero, Is set to the same speed Vtan as
Thereby, for example, when there is no switching of the processing direction at the end point Pn, it is possible to perform processing of the next locus promptly without reducing the processing speed. This makes it possible to smooth the processed surface at the end point Pn.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the arc machining command creation device of the present invention is widely applied to, for example, an analysis support device for analyzing machining dimensions and shapes, a numerical control device for controlling a robot, and the like in addition to being applied to a machine tool as described above. It is possible to apply.

It is the block diagram which showed typically the structure of the circular arc process instruction | command preparation apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the circular arc and division | segmentation point which are produced by the circular arc process command production apparatus of this invention. It is the flowchart which showed the process sequence implement | achieved by the circular arc process instruction | command preparation apparatus of this invention. It is the figure which showed an example of the circular arc process command produced by the command production part shown in FIG. It is a figure for demonstrating the effect of the circular arc process command preparation apparatus which concerns on this embodiment. It is the figure which showed other embodiment in the case of setting the speed of the contact direction in an end point.

Explanation of symbols

11 Division point setting unit 12 Command generation unit

Claims (6)

Division point setting means for setting division points for dividing the arc by a predetermined number of divisions on the arc specified based on the coordinates of the start point, the coordinates of the end point, and the radius given as input information;
Command generating means for generating a circular arc processing command by setting a position coordinate and a velocity vector in a tangential direction for each of the start point, the division point, and the end point;
An arc machining command creation device in which the command creation means sets the velocity vector at the end point to zero.   The command creating means calculates a tangent vector at the end point and a tangent vector at the end point with respect to a next trajectory starting from the end point, and when the change amount of the tangent vector is equal to or greater than a predetermined value, the command at the end point is calculated. The arc processing command generation device according to claim 1, wherein the velocity vector in the tangential direction is set to zero.   The arc processing command generating device according to claim 1 or 2, wherein the command generating means sets the same value to the velocity vector in the tangential direction at each of the start point and the dividing point.   A machine tool for controlling a tool or a workpiece based on an arc machining command created by the arc machining command creating device according to any one of claims 1 to 3. A division point setting process for setting a division point for dividing the arc by a predetermined number of divisions on the arc specified based on the coordinates of the start point, the coordinates of the end point given as input information, and the radius;
A command creation step of creating a circular arc machining command by setting a position vector and a velocity vector in a tangential direction for each of the start point, the division point, and the end point;
An arc machining command creation method in which the command creation process sets the velocity vector at the end point to zero. A division point setting process for setting division points for dividing the arc by a predetermined number of divisions on the arc specified based on the coordinates of the start point, the coordinates of the end point, and the radius given as input information;
An arc machining command creation program for causing a computer to execute a command creation process for creating an arc machining command by setting a position coordinate and a velocity vector in a tangential direction for each of the start point, the division point, and the end point. There,
An arc machining command creation program in which the velocity vector at the end point is set to zero in the command creation process.

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