JPS6234654A - Control system for mold oscillating device - Google Patents

Abstract

PURPOSE:To oscillate a casting mold always with a normal waveform even if the mold oscillating waveform is disturbed by the resonance oscillation of a beam by providing a displacement detector to the mold of a control system which corrects a command signal by the signal from the displacement detector provided to a cylinder for oscillating the mold. CONSTITUTION:The set values from setters 12, 13 for the amplitude of oscillation frequencies are transmitted as the control signal X via a function generator 14 to the cylinder 1 for oscillation through a control amplifier 15, a servocontrol amplifier 16 and a servocontrol valve 17. The mold 2 is oscillated around 3 as a fulcrum by the oscillation of the cylinder 1. On the other hand, the position displacement of the cylinder 1 is detected by a detector 11 and the signal X is corrected by the position signal y1(t) thereof as a feedback signal. The displacement detector 21 is provided to the mold 2 to detect the position signal y2(t) of the mold. The deviation epsilon between said signal and the signal y1(t) is calculated and the signal X is corrected by said signal as the 2nd feedback signal. The correction signal X-Kepsilon (K is the specified amplification factor) is thereafter corrected by the signal y1(t).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a control system for a mold vibration device.

(Prior art and its problems) In the casting process, in order to cool and cast the molten metal without creating casting voids, generally a mold (two
) is attached with a vibration cylinder (1) so as to transmit the vibration, and vibrates using (3) as a fulcrum. In order to control vibration, the mold vibrating device receives set values from the frequency setter 12 and the amplitude setter 13 as a command signal via a function generator 14, and then sends them to a control amplifier 15.
, the servo amplifier 16, and the servo valve 17 to the vibration cylinder (1), while the positional displacement of the vibration cylinder (1) is detected by the displacement detector 11, and the amplifier A Φ ~ ■
A system is adopted in which the command signal is corrected and controlled by returning it as a feedback signal via the . In addition, 1
8 is a spool detector (differential transformer).

However, in the control method of the mold vibration device, the command signal changes from low cycle (15H2 or less) to high cycle (15H2 or less).
582 or higher), the beam causes resonant vibration,
Even though the mold vibration waveform is disturbed, such disturbance cannot be detected, so there is a problem that the vibration waveform cannot be controlled to a normal vibration waveform.

(Problem of the Invention) In view of the limitations of the conventional control system, the present invention aims to provide a system that can control the mold so that it always vibrates with a normal waveform even if the mold vibration waveform is disturbed by the resonant vibration of the beam. Take it as a challenge.

(Point of focus of the invention and its summary) The present invention aims at correcting the mold so that it vibrates with a normal waveform when the mold vibration waveform is disturbed due to the resonant vibration of the beam. The displacement of the mold is detected, and the mold displacement is used as a second feedback signal to correct the command signal.
It was discovered that it is appropriate to perform mold vibration control using the cylinder position signal as a feedback signal. In a control system that controls mold vibration by correcting the command signal X using the cylinder position signal y1(t) from the detector 11 as a feedback signal, the mold vibration cylinder (1
) The displacement detector 21 is placed on the mold (2) which is subjected to vibration work.
is installed to detect the mold position signal y2(t), calculate the deviation ε between the position signal y2(t) and the cylinder position signal y1(t), and use the command signal X as a second feedback signal. A control system for a mold vibrating device, characterized in that after correction, the correction signal X- is corrected by ε (Kε (K...constant amplification factor)) using the cylinder position signal y+(L). It is in.

Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings.

(Embodiment) FIG. 1 is a block diagram of a control system according to the present invention, and FIG. 2 is a flowchart of calculations according to the present invention.

Also in the present invention, as shown in FIG.
2 and the set value from the amplitude setter 13 to the function generator 14.
The command signal X is sent to the vibration cylinder (1) through the control amplifier IS, the servo amplifier 16, and the servo valve 17.
The vibration of the cylinder (1) causes the mold (2) to move (
3) as a fulcrum, while the vibration cylinder (1
) is detected by the displacement detector 11, and the amplifier Aa
The system is basically based on a system in which the command signal is corrected and controlled by returning it as a feedback signal via +p■ to ■.
) The displacement detector 21 is placed on the mold (2) which is subjected to vibration treatment.
is installed to detect the mold position signal y2(t), calculate the deviation ε between the position signal and the cylinder position signal, and correct the command signal X as a second feedback signal. Specifically, as shown in Fig. 2, the mold position signal detected by the detector 21 becomes the position signal y2(t) via the amplifier Amp, and the cylinder position signal y1(t) is added to this signal as a point. Calculate the deviation of both signals ε= yl(t) −y2
(t) is obtained. The above deviation ε becomes ε as a feedback signal through an amplifier All1p■ having a constant amplification factor K, and ε and the command signal X are added to the feedback signal to generate a new correction command signal X- with ε as an error signal. calculate.

Thereafter, in the same manner as in the prior art, the correction signal X- is corrected by ε using the cylinder position signal y1(t).

(Usage example) As a result of changing the command signal for a mold with a natural frequency (18 Hz) from a low cycle of 6 Hz to a high cycle of 30 Hz and observing the mold acceleration and mold vibration waveform, it was found that the vibration frequency was an integer fraction of the above natural frequency. (6H2 and 9 Hz), although the control system shown in Fig. 3 above caused disturbances in the mold vibration waveform, the control system according to the present invention shown in Fig. 1 detected and corrected such disturbances. Therefore, a normal waveform was obtained.

(Operations and Effects of the Invention) As is clear from the above explanation, according to the present invention, not only is mold vibration control performed using a cylinder position displacement signal as a feedback signal, but also vibrations that cannot be detected by such a control method are immediately detected in the cylinder part. Since minute displacements of the mold that are not transmitted are detected and this mold displacement is used as a second feedback signal to correct the command signal and perform mold vibration control, it is possible to detect mold vibrations when the mold vibration waveform is disturbed due to resonance vibration of the beam. It is also suitable for mold vibration control because it corrects the mold so that it vibrates with a normal waveform.

Furthermore, since the mold vibration does not depend on the characteristics of the beam, there is an advantage that the beam can be easily designed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a control system for a mold vibrating device according to the present invention, FIG. 2 is a signal calculation flowchart of the control system, and FIG. 3 is a block diagram showing a conventional control system for a mold vibrating device. (1) ε(K...vibration shilling, (2) ε(K...mold, 11.21ε(K...position displacement detector).

Claims (1)

[Claims] (1) A displacement detector 11 is installed in the mold vibration cylinder (1), and a cylinder position signal y_1(t
) is used as a feedback signal to correct the command signal X to control mold vibration, and a displacement detector 21 is installed on the mold (2) which is vibrated by the mold vibration cylinder (1). mold position signal y
_2(t), calculates the deviation ε between the position signal y_2(t) and the cylinder position signal y_1(t), and
As a feedback signal, first, after correcting the command signal X,
A control system for a mold vibration device, characterized in that the correction signal X-Kε (K...constant amplification factor) is corrected using the cylinder position signal y_1(t).