JPS63138401A - Numerical controller - Google Patents

Abstract

PURPOSE:To simplify the structure of a numerical controller at the side of a servo amplifier by using a position droop at the time of operation, a position command and a position loop gain to attain the automatic correction of the position loop gain. CONSTITUTION:The position droop under the time of stop is read for each fixed time and the offset correction is carried out so as to set the droop value at zero. For this purpose, a speed command auto-tuning part 5 contains a memory 5a which stores the read position droop and an arithmetic means 5b which performs automatic correction of the position loop gain by means of the position droop at the time of operation, a position command and the ideal position loop gain. Thus both offset and position loop gain can be automatically corrected by the part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a numerical control device that controls, for example, the position and speed of an electric motor.

[Conventional technology]

FIG. 2 is a block diagram showing a position and speed loop in a conventional speed command analog output type numerical control device. In this figure, 1 is a servo amplifier, 1a is a volume for speed command analog offset adjustment, 1b is a volume for position loop gain adjustment, 2 is a D/A converter for speed command analog output, 3 is a position detection sound, and 4 is speed detection. θCNI) is a position command, and θ# is a position feedback.

Next, the operation will be explained.

The position feedback θtb detected by the position detection N3 is subtracted from the position command θCM (1, and the position wheel difference, ・
Op2θCIILD-〇#- is obtained, and a voltage proportional to this ζ is outputted from the D/A converter 2 to the servo amplifier 1. Inside the servo amplifier 1 are a speed command analog offset adjustment volume 1a and a position loop gain W.
There is a volume 1b for Ju, and by adjusting these, the offset and position loop gain are adjusted.

[Problem that the invention seeks to solve]

In the conventional speed command analog output type numerical control device as described above, the gain of each axis is balanced<<, and gain adjustment, offset adjustment, etc. are performed using the speed command analog offset adjustment volume la.

The position loop gain must be adjusted using the volume 1b for adjusting the position loop gain, and in addition, during synchronous operation, etc., gain imbalance occurs due to incorrect adjustment, and there is a problem that cutting error increases when machining center cuts a perfect circle. there were.

The present invention was made to solve this problem, and an object of the present invention is to provide a numerical control device that can automatically perform gain adjustment and offset adjustment.

[Means for solving problems]

The numerical control device according to the present invention includes a memory for storing the read position droop, and a memory for storing the read position droop in order to read the position droop while the machine is stopped at regular intervals and perform offset correction so that the value becomes zero. The speed command auto-tuning section includes a calculation means that automatically corrects the position loop gain using the position droop, position command, and ideal position loop gain.

[Effect]

In this invention, the speed command auto-tuning section automatically performs offset I correction and position loop gain correction.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the numerical control device of the present invention.

In this figure, the same symbols as in Fig. 2 indicate the same parts,
Reference numeral 5 denotes a speed command auto-tuning section, which is composed of a memory 5a and a calculation means 5b.

First, offset correction will be explained.

In general, D/A converters, operational amplifiers, etc. have temperature drift factors and steady-state errors, so even if the command before D/A t11 is "0", they will generate a minute output, and that value will change depending on temperature changes, etc. It fluctuates. The amount of variation is expressed as a steady deviation (D, . . . ) in the position loop. This droop should be “O” when stopped (command -〇), but
If X is caused by the above reason, the position has moved by X.

Therefore, in order to compensate for this positional shift due to temperature changes,
Stops at regular intervals, position droop D in the middle (command = 0)
,,. . , and stores it in the memory 5a as the 0FSET value.
OF S E ′ so that the value is ON.
Add or subtract the r value.

Now, assume that the current 0FSET value = 3 (pulse) position droop (while stopped) = 2. .

Now, assume that the speed control system is balanced at θCND-〇#b=2. This Dr. , to always keep the value 0
All you have to do is change the FSET value. Now, the output of point A--1
Since the speed loop system and below are balanced, 0FSET
If value=1, then Dl. . , = 0.

This correction is to correct temperature drift of the analog system below point A in real time. Therefore, OFS
l! , 'Change the r value so that it always becomes DrIloP20.

Next, the gain correction that is performed after the offset correction will be explained.

If the current position loop gain is , then the position deviation is Dr. ,=θcno/Kp.

Also, let the ideal position loop gain be KP', and D/
When the output of the A converter 2 is a D/AO complement, the following calculation is required in order to bring the position loop gain closer to 11 by gain correction.

D7°. Ge = θcND/KPI11 (D,...ge: Ideal position droop) (Kge = ideal position loop gain) K"D/AO supplement"Un Dl. . , Can be controlled.

Furthermore, the output of the D/A converter 2 when this gain correction is not performed is D /A O = Droop ・k, and if the position loop gain at this time is /, then θcp*o = k p 'D. . .

Thealcala, K, ``1.t, determined by the D/A O to D/A O complement ratio α.

therefore, k = α, ′ = Commercial moxibustion ＾? To L-x, t = q effect P = K.

and becomes equal to the parameter setting value.

In this way, the position loop gain can be corrected in real time.

Furthermore, since offset sampling is performed at regular intervals, temperature drift of operational amplifiers, etc. can be corrected.

〔Effect of the invention〕

As explained above, this invention includes a memory for storing the read position droop, and a memory for storing the read position droop in order to read the position droop while the machine is stopped at regular intervals and perform offset correction so that the value becomes zero. A calculation means that automatically corrects the position loop gain using the position droop, the position command, and the ideal position loop gain.
Equipped with a speed command auto-geuning unit that eliminates the need for adjustment using variable resistors on the servo amplifier side and the command output side, which simplifies the structure of the servo amplifier side and eliminates the need for cutting, which would otherwise be caused by inadequate gain adjustment. Since there are no cutting errors, it is possible to obtain products with higher reliability and precision.

Furthermore, since the gain is set by a parameter, minute gain adjustment is possible, and the offset is also sampled at regular intervals, so there is an effect that temperature drift of the element can be corrected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the position and velocity loops in the -'A embodiment of the numerical control device of the present invention, and FIG. 2 is a block diagram showing the position and velocity loops in a conventional numerical control device. In the figure, 1 is a servo amplifier, 2 is a D/A converter, 3 is a position detector, 4 is a speed detector, 5 is a speed command auto-tuning section, 5a is a memory, and 5b is a calculation means. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Diagram 1 procedural amendment (voluntary)
, Title of the invention Numerical control device 3, Relationship to the case of the person making the amendment Patent applicant Representative Moriya Shiki 4 Address of agent Mitsubishi Electric Corporation, 2-2-3 Marunouchi, Chiyoda-ku, Tokyo 5, Amendment Insert the following in column 6 of the detailed explanation of the invention in the subject specification, next to "The position is Xt! It has been displaced." in page 4, line 20 of the specification of contents of the amendment. 1 (However, it is assumed that there are no position error factors in the feedback system other than the above causes.)

Claims (1)

[Claims] In a numerical control device equipped with a servo amplifier that is analog-controlled by a speed analog command, the position droop during a stop is read at regular intervals, and the read position droop is used to perform offset correction so that the value becomes zero. Equipped with a speed command auto-tuning section consisting of a memory for storing and a calculation means that automatically corrects the position loop gain using the position droop during operation, the position command, and the ideal position loop gain. A numerical control device featuring: