JPS62198902A - Correction for numerical controller - Google Patents

Abstract

PURPOSE:To attain the continuous correction of errors by using the interpolation of rectilinear approximation of the absolute correction amounts set equidistantly to obtain the pitch error of a feed screw with axis control of a tool machine. CONSTITUTION:If the present position of a machine is set at a point P, a dividing point P1 is equal to P/(correction interval L). Thus it is known that the machine is positioned between the point P1 and a point P2(=P1+1). Furthermore it is understood that the machine is set at a position between both points P1 and P from P=P1 (interval L). Therefore the absolute correction amount (a) is shown by an equation I for the present machine position. The (a-b).omega is equal to the correction amount to the interpolation output DELTAi as shown by an equation II. Thus the errors can be continuously corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a correction method for a numerical control device that corrects mechanical errors in a machine tool.

[Conventional technology]

FIG. 3 is a block diagram showing the configuration of a conventional numerical control device. In the figure, 1 is a CRT, 2 is a keyboard, and 3 is a main body of the numerical control device. Processing such as error correction 5 is performed. 6 is an amplifier, 7 is a motor, and 8 is a detector.

Next, the operation in Figure 3 is explained below at kinship intervals (
The correction interval L) is set. Each time the machine passes a dividing point, the motor 7 driven by the operation command of the numerical control device main body 3 refers to the correction data table provided in the numerical control device main body 3 and adjusts the vertical axis. Add the absolute correction amount to the interpolated output data. Since the absolute amount of error at that point (region) is stored in advance in this absolute correction amount, when correcting the error, the difference from the previous absolute correction amount is calculated.

[Problem that the invention seeks to solve]

Since pitch error correction processing in conventional numerical control devices is executed as described above, the amount of correction can only be applied to interpolated output data at dividing points that have been divided in advance; There was a problem in that error correction could not be performed continuously.

This invention was made to solve the above-mentioned problems.The pitch error of the feed screw in axis control of machine tools is determined as an absolute correction amount at each division point set at equal intervals, and is calculated by linear approximation. It is an object of the present invention to provide a correction method for a numerical control device that performs correction by interpolation.

[Means for solving problems]

A correction method for a numerical control device according to the present invention calculates the machine position at regular intervals during correction processing, obtains an absolute correction amount, and inputs the absolute correction amount into interpolated output data.
This is what I did.

[Operation] In the error correction of the numerical control device according to the present invention, the absolute correction amount is continuously determined and the correction is performed during the operation of the machine.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In Figure 1, the same parts as in Figure 4 are indicated with the same reference numerals.The figure shows a diagram of the principle of correction in this invention, and shows interpolation by linear approximation of the absolute correction amount at each division point. According to the method, the pitch error of the feed screw in axis control of machine tools is determined and corrected.

Next, the operation of the present invention will be explained below.

First, as shown in Fig. 2, when the current machine position is at point P, the dividing point PL is Pl=P/(correction interval L)...
...(1), and the machine divides points P1 and P2 (=)'1
+1). Furthermore, P=)'-PL・(correction interval L) ・・・・・・・・・
...(2) shows that the machine exists at a position P from the dividing point Pl.

As explained above, the absolute correction amount a at the current machine position is a = (a2-a1) ・(P/(correction interval))
+al ・13), and the previous absolute correction amount is 5
If the coefficient for increasing the width of the absolute correction amount is ω, then (a−b)φω becomes the correction value for the interpolation output Δi of the present invention, which is expressed by equation (4).

Δi=Δ1-1-(a-b)・ω ・Old...Song (4) [Effects of the Invention] As described above, the correction method of the numerical control device according to the present invention improves the feed timing in axis control of machine tools. Since the pitch error of the screw is determined by interpolation of linear approximation of the absolute correction amount set at equal intervals, it is possible to continuously correct the error, which has the effect of enabling high-precision machining. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of pitch error correction according to the present invention, Fig. 2 is a detailed explanatory diagram of pitch error correction according to the invention, Fig. 3 is a block diagram showing the system configuration of a numerical control device, and Fig. 4 is a conventional diagram. FIG. 3 is an explanatory diagram of correction in the numerical control device of FIG. In the figure, PO is a reference point, D is a division point, L is a correction interval, 3 is a numerical control device main body, 4 is an interpolation, and 5 is a pitch error correction. Patent applicant Mitsubishi Electric Corporation Figure 1 Procedural amendment for deflection pair correction (voluntary) Showa 6 unit 7・”1q7B

Claims (2)

[Claims] (1) Pitch error correction function that corrects the pitch error of the feed screw in axis control of machine tools, and dividing points that divide the machine position at equal intervals around the reference point, and the absolute correction amount of the machine position that you want to correct. In a correction method for a numerical control device in which the main body of the numerical control device is equipped with an interpolation function that calculates the amount by interpolation, the machine position is calculated from the division points provided at equal intervals, and the absolute correction amount is directly approximated. 1. A correction method for a numerical control device, characterized in that the absolute correction amount is determined by an interpolation method and added to interpolated output data. (2) The numerical control according to claim 1, wherein the absolute correction amount is calculated by the numerical control device main body that performs the correction process by measuring the machine position at regular intervals. How to correct the device.