JPH0160340B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention vibrates the vibration system of the beam supporting the mold using an electro-hydraulic servo device when continuously casting slabs in a mold to ensure defect-free casting. The present invention relates to a control method and a control device for a mold vibration device for obtaining slabs.

(Prior Art) In the continuous casting method, it is necessary to reduce the friction between the slab and the mold to prevent seizure of the slab or breakout accidents. Therefore, in order to reduce the friction between the mold and the slab, continuous casting is carried out using the so-called mold vibration method, in which casting is performed while the mold is vibrated up and down.

In continuous casting equipment using the mold vibration method, for example, as shown in FIGS.
The vibrating beam 2 is rotatably supported by a fixed pedestal 7 at one end on a vibration fulcrum 6, and an electro-hydraulic servo device with one end of that side provided on the base of the pedestal 7. The vibration system of the vibration beam 2 including the mold 4 is vibrated with respect to the pedestal 7 via the vibration guide 3 about the fulcrum 6 by the operation of the vibration cylinder 1 .

By the way, in the mold vibration type continuous casting equipment as described above, the electro-hydraulic servo device 8 has conventionally been driven by a control device as shown in FIG. 3, which can control the vibration frequency setting and the vibration amplitude separately. I was trying to do that.

In FIG. 3, 11 is a frequency setter, 12 is an amplitude setter, 13 is a function generator, 14 is a control amplifier, and 15 is a servo amplifier, which outputs from a differential transformer 17. The position signal of the cylinder 18 of the electro-hydraulic servo device 8 is amplified by an amplifier 19, and the deviation between the output of the function generator 13 and the output of the amplifier 19 is detected at a summing point 20. This deviation is amplified by the control amplifier 14, and its output is combined with the servo valve 16 output from the other differential transformer 21.
The deviation from the output of the amplifier 22 which amplifies the spool position signal is detected at the summing point 23, this deviation is input to the servo amplifier 15, and the servo valve 16 amplifies the output of the function generator 13. cylinder 18 according to
is driven to vibrate the vibrating beam 2 and vibrate the mold 4.

Generally, in continuous casting equipment using the mold vibration method as described above, it is known that increasing the vibration frequency of the mold 4 reduces the incidence of oscillation defects. When the frequency of the output of 13 is increased from around 1 Hz to about 30 Hz, the amplitude of the vibrating beam 2 becomes abnormal due to resonance at around 15 Hz, where the above frequency matches the natural frequency of the vibration system of the vibrating beam 2. It grows to
After that, the above-mentioned amplitude attenuated, and it was not possible to obtain the prescribed amplitude value in the high frequency region around 30 hertz. In addition, in order to correct the above-mentioned attenuation of the amplitude of the vibrating beam 2, a control amplifier 14 and a servo amplifier 1 are used.
When the gain of 5 was changed, the stability condition of the control system changed, and there was a risk that the control system would diverge.

(Object of the Invention) The present invention has been made in view of the above circumstances, and its object is to provide a control method for a mold vibration device that vibrates a mold using an excitation signal output from a function generator. If the amplitude of the mold is smaller than the generator's amplitude setting, the amplitude setting is corrected to be larger than the generator's amplitude setting, so that it can be applied to a high frequency region without changing the transfer function of the control system. The object of the present invention is to obtain a method of shaking the mold with a sufficient vibration width.

Another object of the present invention is to convert a position signal of a cylinder that vibrates a mold into an amplitude signal in a control device for a mold vibration device that vibrates a mold using an excitation signal output from a function generator. The transfer function of the control system is changed by providing an amplitude detector and correcting the amplitude setting value of the function generator so that the amplitude of the mold output from the amplitude detector matches the setting value. To obtain a stable control device for a mold vibrating device that can vibrate a mold with a sufficient amplitude in a high frequency range without causing vibrations.

(Structure of the Invention) To summarize the present invention, an electro-hydraulic servo device is driven in response to an excitation signal having a preset amplitude and a preset frequency outputted from a function generator, and the electro-hydraulic A control method for a mold vibration device in which a mold supported by a beam connected to a cylinder of a servo device is vibrated, the method comprising: converting a position signal of the cylinder into an amplitude signal;
Calculate the deviation between this amplitude signal and the set amplitude above,
Multiply this deviation by a coefficient and add it to the set amplitude above,
The output is set as a new set amplitude of the function generator, and the set amplitude is corrected according to the above amplitude signal of the cylinder in a high frequency range including the natural frequency of the vibration system of the vibrating beam, and the mold is vibrated. This is a method of controlling a mold vibration device, characterized in that:

The present invention also provides an electro-hydraulic servo device that is driven in response to an excitation signal having a set amplitude and a set frequency that are arbitrarily set in advance and is output from a function generator, and that is coupled to a cylinder of the electro-hydraulic servo device. A mold vibrating device in which a mold supported by a beam is vibrated, includes an amplitude detector that converts the position signal of the cylinder into an amplitude signal, and a deviation that calculates the deviation between the amplitude signal and the set amplitude. comprising a detector, and an adder that multiplies this deviation by a coefficient and adds it to the set amplitude, and outputs the result as a new set amplitude signal of the function generator,
The control device for a mold vibrating device is characterized in that the set amplitude is corrected in a high frequency range including the natural frequency of the vibrating beam in accordance with the amplitude signal of the cylinder.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

A block diagram of a control device for a mold vibration device according to the present invention is shown in FIG.

In the block diagram of FIG. 4, blocks corresponding to those in FIG. 3 are denoted by the same reference numerals, and a description of the blocks will be omitted to avoid duplication.

In FIG. 4, 31 is an amplitude detector, 32 is an amplifier, 33 is a summing point, 34 is an amplifier, and 35 is a summing point.

The amplitude detector 31 is a circuit that converts the position signal of the cylinder 18 into an amplitude signal of the cylinder 18 from the signal input from the amplifier 19, and this amplitude signal is amplified by the amplifier 32. After that, add point 3
3 is entered.

The summing point 33 is a deviation detector that detects the deviation ε between the set amplitude input from the amplitude setting device 12 and the amplitude signal of the cylinder 18 amplified by the amplifier 32. The deviation ε is input to an amplifier 34 having a constant amplification factor K, and the amplifier 34 outputs a signal of Kε.

The signal Kε and the set amplitude signal output from the amplitude setter 12 are added at a summing point 35 constituted by an adder, and the output of this summing point 35 functions as a new set amplitude signal. It is output to the generator 13.

In the conventional control device shown in FIG. 3, when the setting amplitude signal for vibrating the cylinder 18 with an amplitude of 3 mm is output from the amplitude setting device 12, the cylinder 18 is, for example, 1.5 mm in amplitude. If the vibration only occurs with an amplitude of mm, the control device shown in Fig. 4 will:
The cylinder 18 can be vibrated with an amplitude of 3 mm in the following manner.

That is, in the control device shown in FIG. 4, the amplitude of the vibration of the cylinder 18 is 1.5 mm,
The detected value is input to the amplifier 32 and then input to the summing point 33 as a signal for the amplitude of 1.5 mm. At this addition point 33, it is added to the set amplitude signal of 3 mm input from the amplitude setting device 12, and from the addition point 33, (3-1.5)
A signal corresponding to =1.5mm is output. This signal is amplified by the amplifier 34, and the amplification rate K is set to K
If =1, a signal corresponding to 1.5 mm is output from the amplifier 34 to the summing point 35.

At the above summing point 5, 1.5mm from the amplifier 34
The signal corresponding to the amplitude setting device 12 and the above-mentioned set amplitude signal of 3 mm are added, and (1.5 + 3) = 4.5 mm.
A new set amplitude signal will be output to the function generator 13.

In this state, in the control device shown in Fig. 3, the setting amplitude signal input to the function generator 13 is
Corresponding to the case of increasing to 4.5mm, cylinder 18
The swing width can be increased up to 3mm.

In this case, the transfer function of the control system after the function generator 13 does not change, and therefore the stability also does not change.

Further, when the amplitude of the cylinder 18 is 3 mm and equal to the setting amplitude signal output from the amplitude setting device 12,
The deviation ε between the two becomes ε=0, and the set amplitude signal outputted from the amplitude setter 12 from the adder 35 is input as is to the function generator 13.
The cylinder 18 vibrates with a set amplitude signal input to the amplitude function generator 13.

As described above, by controlling the setting amplitude signal input to the function generator 13 according to the amplitude of the vibration of the cylinder 18, the vibration can be controlled without changing the transfer function of the vibration control system of the cylinder 18. The cylinder 18 can be vibrated with the amplitude set by the width setting device 12.

In the above embodiment, the amplification rate K of the amplification device 34 may be selected to match the amplitude set by the amplitude setting device 12.

Next, another embodiment of the present invention is shown in FIG.

In the embodiment shown in FIG. 5, in the control device shown in FIG. 4, the set amplitude outputted from the amplitude setter 12 is corrected by digital signal processing. 42 is a microcomputer that detects the amplitude as a digital signal; 43 is a D/A converter that generates a vibration waveform signal of the cylinder 18 in accordance with the digital signal output from the microcomputer 42;

The microcomputer 42 is, for example,
Steps 101 to 107 of the flowchart shown in FIG. The amplitude of the vibration waveform signal to be output is controlled.

If you do the above, the microcomputer 4
2 determines whether A=S or not. If A=S, S is output as is as a new setting amplitude signal, and when A≠S, Kε+S is output as a new setting amplitude signal. It is possible to always match the vibration amplitude of the cylinder 18 to the amplitude set by the amplitude setting device 12 by outputting it as a width signal.

In the embodiments described above, the set value is immediately corrected based on the vibration result, but this poses a risk of misjudging a deviation caused by some kind of disturbance.

However, misjudgment of the deviation caused by the above-mentioned disturbance can be caused by, for example, extracting only the frequency command value component of the mold through a bandpass filter.

Check the upper and lower limits of the amplitude.

Use the average value of the vibration waveform of the mold.

This can be prevented by using well-known techniques such as.

(Effects of the Invention) As is clear from the above detailed description, in the control system of the mold vibration device, when the vibration amplitude of the mold is smaller than the vibration width setting value, the apparent Since the amplitude setting value is corrected to be larger, the transfer function of the control system does not change, and even in the high frequency region around 30 Hz, the stable control system allows molding to be performed with a sufficiently large amplitude. can be excited.

Furthermore, according to the present invention, stable mold vibration can be achieved by simply adding a relatively simple device outside the conventional mold control system, and the mold can be vibrated with a sufficiently large amplitude at a high frequency. A control device for the device can be obtained.

[Brief explanation of drawings]

1 and 2 are a side sectional view and a plan view showing a part of a continuous casting device, respectively, FIG. 3 is a block diagram of a conventional control device for a mold vibration device, and FIG. 4 is a mold vibration according to the present invention. FIG. 5 is a block diagram of another embodiment of the control device for the mold vibration device according to the present invention, and FIG. 6 is a block diagram of another embodiment of the control device for the mold vibration device according to the present invention. It is a flowchart showing the operation of a microcomputer. 4...Mold, 8...Electro-hydraulic servo device, 11
...Frequency setting device, 12...Swing width setting device, 13...
...function generator, 18 ... cylinder, 31 ... amplitude detector, 33, 34 ... addition point, 41 ... A/
D converter, 42...Microcomputer, 43
...D/A converter.

Claims (1)

[Claims] 1. An electro-hydraulic servo device is driven in response to an excitation signal having a set amplitude and a set frequency that are arbitrarily set in advance and output from a function generator, and the cylinder of the electro-hydraulic servo device is driven. A control method for a mold vibration device in which a mold supported by connected beams is vibrated, the method comprising: converting the position signal of the cylinder into an amplitude signal;
Calculate the deviation between this amplitude signal and the set amplitude above,
Multiply this deviation by a coefficient and add it to the set amplitude above,
The output is used as the new set amplitude of the function generator, and the set amplitude is corrected according to the above amplitude signal of the cylinder in a high frequency range including the natural frequency of the vibration system of the vibrating beam, and the mold is vibrated. A method for controlling a mold vibration device, characterized in that: 2. An electro-hydraulic servo device is driven in response to an excitation signal having a set amplitude and a set frequency that are arbitrarily set in advance and is output from a function generator, and is supported by a beam coupled to the cylinder of the electro-hydraulic servo device. A mold vibrating device configured to vibrate a mold that has been rotated, comprising: an amplitude detector that converts the position signal of the cylinder into an amplitude signal; a deviation detector that calculates a deviation between the amplitude signal and the set amplitude; an adder that multiplies this deviation by a coefficient and adds it to the set amplitude, and outputs the result as a new set amplitude signal of the function generator;
A control device for a mold vibration device, characterized in that the set amplitude is corrected in accordance with the amplitude signal of the cylinder in a high frequency range including the natural frequency of the vibration system of the vibrating beam.