JPS62182807A - Interpolation unit for numerical controller - Google Patents

Abstract

PURPOSE:To easily obtain a desired locus by providing plural curve tracking parts and one or plural connection arithmetic parts which connect the output of those curve tracking parts. CONSTITUTION:A speed arithmetic part 11 and curve tracking parts 12 and 13 are equal to conventional ones respectively. Here, plural curve tracking parts are newly added and furthermore the outputs P and Q of both parts 12 and 13 are sent to the connection arithmetic parts 14 and 15. At the same time, the outputs of both parts 14 and 15 are used as the commands X and U to be given to a servo system. Thus both commands X and U are shifted over an XY plane 20 and a UV plane 21 respectively and therefore the desired taper processing is attained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an interpolator for a numerical control device.

[Conventional technology]

In a numerical control device, a servo system has an interpolator to draw a desired trajectory. As shown in FIG. 4, the interpolator consists of a speed calculation section l to which a command speed signal a is input and a curve tracking section 2 to which a command curve signal is input. It becomes a command to. The speed calculation section 1 determines the calculation speed of the curve tracing section 2 so that the speed of the servo system follows the command, and the curve tracing section 2 determines the calculation speed of the servo system so that the trajectory of the servo system follows the commanded curve, such as a straight line or a circle. , trace the curve.

The algorithm of the curve tracing section 2 is the DDA method.

Various methods such as algebraic calculation method and minimum deviation method have been devised and announced.

[Problem that the invention seeks to solve]

As the fields to which numerical control devices are applied expand and the shapes of workpieces processed by numerical control devices become more diverse, the need for interpolation functions also increases.

For example, a wire-cut electrical discharge machine uses a machining method called Taber machining, in which a workpiece 4 is machined while the wire 3 is tilted from the vertical line by a commanded angle, as shown in Fig. 5. It is something. The numerical control device fixes both ends of the wire 3 in the XY plane and the U
It is necessary to control each trajectory on the V plane. However,
What is commanded by the program is a trajectory on a plane called a program plane, and if a desired trajectory is to be obtained on the program plane, the trajectory on the XY plane and UV plane must exhibit complex movements. This situation is shown in FIG. 6th
In the figure, the locus 5 on the program plane is composed of circles and straight lines, but the locus 6 on the XY plane and the locus 7 on the UV plane are neither circles nor straight lines. In this figure, the subprogram plane is a virtual plane for creating a taper angle, and its locus 8 is created by offsetting the locus 5 of the normal program plane.

Furthermore, when attempting to process a workpiece 9 with a vertically irregular shape as shown in FIG. 7 using a milling machine that includes an end mill 10,
Each cross section (one cross section is shown in FIG. 7(b)) is a very complicated curve.

The interpolator of a general numerical control device has linear and circular interpolation functions. There are also interpolators that have the function of interpolating quadratic curves such as ellipses and parabolas.

However, in cases such as the above example, the desired trajectory cannot be expressed simply mathematically, so in order to track it, the desired trajectory must be divided into straight lines using an automatic programming device or an automatic programming function inside a numerical control device. , it was necessary to give detailed straight line instructions to the interpolator. However, in this case, it is necessary to introduce an expensive automatic programming device, and the load on the main data processing section inside the numerical control device becomes heavy, resulting in a decrease in performance.

Means for Solving Problem C] In order to solve such problems, the present invention provides a plurality of curve tracing units, and one or more combination calculation units that combine the outputs of the respective curve tracing units. It was designed to provide a.

[Effect]

In the present invention, the output of the coupling calculation section becomes a command to the servo system.

〔Example〕

A first embodiment of an interpolator of a numerical control device according to the present invention is described below.
As shown in the figure. In FIG. 1, the speed calculating section 11 and the curve tracing section 12.13 are the same as those of the conventional one, but there are a plurality of curve tracing sections and the output curve of the curve tracing section 12.13 is different. This differs from the conventional method in that the output signal -5 is guided to the connection calculation section 14.15, and the output of the connection calculation section 14.15 is the commands X and U to the servo system. P, Q,
The dimensions of X and U depend on the dimensions of the required space.

Next, a case will be described in which taper machining of a wire-cut electrical discharge machine is realized using this embodiment.

Let P, Q, X, and Dan be two-dimensional vectors. In particular, Let it be a vector on the program plane.In Fig. 2, trace the curve given as a command on the program plane 16, and first trace the curve on the subprogram plane 17.Only trace 1
8 is obtained by offsetting the locus 19 on the program plane by an amount corresponding to the taper angle θ.

Now, in FIG. 3, at a certain point, Δ-? Suppose that it moves by -1Δ days. At this time, in the combination calculation unit 14.15, ΔX=K 1・ΔP+2・AQ (3) ΔU=
The following calculation is performed: 3 ・Δ−P+ 4 ・AQ− ・ ・ (4). Here, K1= (hl/h2)+1...(5)K2=-h
l/h2...(6) K3=-h3/h2
...(7)K4= (h3/h2)+1...
...(8). From Figure 3, the above equation shows that there is a relationship of (Δ or - Δdan)/hl = (Δdan - Δdan)/h2 = (Δdan - Δdan)/h3... (9) Since it is obvious, it can be obtained by solving this equation.

As described above, entry and exit are respectively on the XY plane 20 and U
By moving on the V plane 21, desired taper processing can be obtained.

Note that, due to the structure of the machine, the UV plane 21 is often a moving coordinate on the XY plane 0. At this time, U'=U-X・
...00) From (71, instead of formula (8), K3=4= (hl+h2+h3)/h2-0.-0
It may be set to 0.

Based on the same idea, it is clear that in the case of the vertically irregular shape shown in FIG. 7, one curve tracing section may be used to trace a straight line (square), and the other curve tracing section may be used to trace a circle.

In addition, in FIG. 1, two curve tracking units and two connection calculation units are provided, but the present invention is not limited to this number.

〔Effect of the invention〕

As explained above, the present invention allows a desired trajectory to be easily obtained by providing a plurality of curve tracing units and one or more combination calculation units that combine the outputs of the respective curve tracing units. , tracking of various trajectories that was impossible with conventional numerical control devices is now possible only within the interpolator, allowing new machining methods not only for wire-cut electric discharge machining but also for machines with multiple (complicated degrees of freedom). Alternatively, it becomes possible to develop new programming methods for complex curves, and the effects are enormous.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of an interpolator of a numerical control device according to the present invention, FIGS. 2 and 3 are explanatory diagrams for explaining an example of Taber machining by this device, and FIG. A system diagram showing the interpolator of a conventional numerical control device, Figures 5 and 6 are explanatory diagrams to explain Taber machining with a wire-cut electric discharge machine, and Figure 7 (a) shows machining of an object with a vertically irregular shape. 7(b) is an explanatory diagram for explaining the
FIG. 11... Speed calculation section, 12.13... Curve tracking section, 14.15... Connection calculation section.

Claims (1)

[Claims] A numerical control device comprising a plurality of curve tracing sections and one or more combination calculation sections that combine the outputs of the respective curve tracing sections, and the output of the combination calculation section is used as a command to a servo system. interpolator.