JPS62105203A - Interpolating method for numerical controller - Google Patents

Abstract

PURPOSE:To interpolate an optional free curve smoothly by a simple function generating device by controlling three axes by the function generating device based on a specific interpolation expression among a time base as a virtual parameter and plural control axes, and synchronizing the axes with one another. CONSTITUTION:NC command data 1 is inputted to an NC controller 2, whose output is inputted to X, Y, and Z axis function generators 3-5 and a pulse oscillator 6. The outputs of the function generators 3-5 and clock pulse oscillator 6 are inputted to X, Y, & Z counters 7-9. The function generators 3-5 sends the complement of a pulse interval to the counters 7-9 according to a speed function A+Bt+Csin(Dt+E), where t=0-1. In this case, constants A-E are variable numbers and specified by a controller 2. The counters 7-9 send an X-, a Y-, and a Z-axial pulse to X-, Y-, and Z-axial motor controllers 10-12 to synchronize the control axes with each other.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to an interpolation method in a numerical control device applied to, for example, a machine tool or an industrial robot, and particularly relates to an interpolation method in a numerical control device that requires three-axis control. A tilted arc,
Alternatively, the present invention relates to an interpolation method in a numerical control device that smoothly interpolates curves that cannot be represented by mathematical expressions.

(b) Prior art The interpolation method in a numerical control device applied to a conventional NC machine tool or an industrial robot is, for example, when interpolating about two axes, the X axis and the Y axis, the shape to be interpolated is expressed by the function Y By solving =f(X), the coordinate values on the curve to be interpolated are found, and a fixed pulse train is distributed to each axis.

(C) Problems with the Prior Art According to the interpolation method in the conventional numerical control device described above, although it is possible to perform linear interpolation, biaxial circular interpolation, or curved interpolation expressed by a certain mathematical formula, for example, circular interpolation is possible. Even in the case of interpolation, when attempting to interpolate an inclined circular arc that requires three-axis control, a new three-axis circular interpolation calculation device is required, so this method has not been put into practical use very often. Furthermore, in the case of a free curve that cannot be expressed mathematically, there is no means of interpolation at all, and
There is no other way than to decompose the arc or straight line I by calculation and approximate interpolation based on the decomposition formula, and it is difficult to perform smooth curve interpolation like Vl. Furthermore, as seen in a 4-axis wire node control device, if you try to perform M-line interpolation on the X1, Y, and 2 axes, and circular interpolation on the U, V, and 2 axes, synchronization between the two sets of interpolation cannot be achieved. Therefore, in this case as well, there was no other way than to decompose it into straight lines.

(d) Technical Problems of the Present Invention Therefore, the present invention has been made in order to eliminate the drawbacks of the interpolation method in the conventional numerical control device as described above. It is set as a function of a certain parameter, and a pulse train is generated on each axis side accordingly. In this case, an interpolation method is used to synchronize each axis by preparing separately or using [1...j]. In other words, in the invention of 1.:, when controlling two axes, J' is added to the three axes with preset parameters.
When controlling three axes (J, the variable make is added. Interpolation is performed using one axis, and for each actual drive axis, two-axis interpolation with the above parameters is executed independently, and an arbitrary curve is created. The object of the present invention is to provide an interpolation method in numerical control that makes it possible to perform interpolation or synchronization between multiple axes.

(e) Technical Means of the Present Invention In order to achieve the above-mentioned object, the present invention specifically sets a time axis (↑) as a virtual parameter and controls a plurality of control axes to be controlled. (X), (Y), <2)・
..., the interpolation formula between each control axis and the time axis (t) is as follows: X=Fx(t), Y=Fy(t), 2=Fz
(t) ..., a function generator is provided for each control axis, and each control axis is controlled at preset time intervals to synchronize the axes. This is an interpolation method used in numerical control equipment.

(f) Effect of the present invention This invention uses the above-mentioned technical means to generate not only curves that can be expressed by a mathematical formula, such as a three-axis conic section, but also curves that cannot be expressed by a mathematical formula, using one type of function generator. Curves can also be smoothly interpolated and controlled. Its mode is shown in FIGS. 1 and 2.

When smoothly interpolating between the two points (Po, P, > shown in FIG. 1), a velocity curve as shown in FIG. 2 is obtained.

In FIG. 2, Io, Jo, K. is point P in FIG. is the direction cosine of I,,J,,Ig,is the point P
, is the direction cosine of . Velocity function x=l' about the X axis
x(t) is the starting point cto, io), the ending point (t,,
1. ), the distance traveled is ft, fx
(t) determined by dt. The velocity function y=fy(t) on the Y axis is the starting point (to, Jo) and the ending point (t+
, J,), the distance traveled is f: f
It is determined by y(t)dt. The velocity function z=fz(t) about the Z axis is the starting point no, Ko) and the ending point (t,
, K,), the moving distance is Is fz
(t) dt.

(g) Description of Examples Regarding the interpolation method in the numerical control device according to the present invention, the third section describes the case where the interpolation method in the numerical control device of the present invention is applied to a three-axis milling machine control device for X, Y, and Z axes to interpolate a conic curve.
The explanation will be based on the block diagram shown in the figure. In the block diagram shown in FIG. 3, NC command data (t) is
Input to NC control 1 chorus (2). @XaNC controller (-The output of the roller (2) is used as control data for the X-axis function generator (3) and Y
These are input to an axis function generator (4) and a Z-axis function generator (5), respectively. On the other hand, at the same time, the NC controller 1-roller (2
) is output from a clock pulse generator IH (f
3) Enter. The outputs of the respective axis function generators (3), (4) and (5) and the clock pulse oscillation! (6)
The output of each axis function generator (3), (4) and (
In connection with step 5), the respective profits are input to the X-axis counter (7), Y-axis counter (8) and Z-axis counter (9). Each axis function generator (3), (4
) and (5) define the velocity function A + B as Cs1
Send the complement of the pulse interval to the counter according to n(Dt+E), t=O~l. In the above formula, constants A, B, C, D and E are variable numbers, and NC
Specified by the controller. At the counter,
The numerical value sent from each axis function generator is incremented according to the clock pulse from the clock pulse oscillator, and when an overflow occurs, the pulse is sent to the motor controller (t0), (It).

(t2), and the next data is received from each axis function generator. Said NC controller (2)
determines the constant of the speed function for each axis in accordance with the input NC command data (t), sends it to each axis function generator, and also controls the frequency of the clock pulse oscillator.

(hl) Effects of the Present Invention According to the present invention, in the above-described specific configuration, an arbitrary free curve can be smoothly interpolated using a simple function generator. In addition, since it is sufficient to specify coordinate values and direction cosine for NC command data, the cost of creating NC command data and the cost of information transmission can be significantly reduced. It can be said that this is extremely advantageous.

[Brief explanation of drawings]

Figure 1 shows a starting point P in three-axis space. Coordinate diagram illustrating the aspect of the interpolation curve from to the end point P1, FIG. 2 A-C
is a coordinate diagram showing a speed curve when smoothly interpolating from the starting point P0 to the ending point P1 in FIG. 1. FIG. 3 is a block diagram showing an example of application to a three-axis milling machine control device. (t)・・・・・・・・・・・・・・・NC command data (2)・・・・・・・・・・・・・・・N
C controller (3) to (5)...Function generator (6)...Clock pulse oscillator (7) to ( 9)・・・・・・・・・
Counter (lO) ~ (t2)...Motor controller patent applicant Kyowa No. 1 Engineering Co., Ltd. Agent Ken Shinji (1 other person) Fig. 2 Q + 1 i dimension -11-S:″″

Claims (1)

[Claims] A time axis (t) is set as a virtual parameter, and the relationship between the time axis (t) and the plurality of control axes (X), (Y), (Z), etc. to be controlled is determined for each control axis. The interpolation formula between
X=Fx(t), Y=Fy(t), Z=Fz(t)...
- In a numerical control device characterized in that a function generator is provided for each of the control axes, and each control axis is controlled at preset time intervals to achieve synchronization between the axes. Interpolation method.