JP2986328B2 - Mold vibration device in continuous casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration device for a mold in a continuous casting facility.

[0002]

2. Description of the Related Art Vibration is applied to a mold in a continuous casting facility by a vibrating device. A conventional vibrating device of this type is disclosed in Japanese Patent Application Laid-Open No. 63-63562.

That is, in Japanese Patent Application Laid-Open No. 63-63562, a mold is supported via a four-sided link and a beam so as to be able to move up and down in a vertical plane.
A hydraulic cylinder for vibrating the mold is connected to the tip of the beam, and a hydraulic circuit for the hydraulic cylinder is provided with a servo valve and a control circuit for controlling the servo valve.

In this control circuit, the rod position of the hydraulic cylinder and the acceleration of the mold are detected by sensors, respectively, and the detected values are fed back so that the vibration of the mold is adjusted to a predetermined vibration waveform. As a result, the vibration transmission characteristics are improved.

[0005] The need to improve the vibration transmission characteristics as described above is based on the following reasons. That is, recently, in order to improve the quality of the surface of a slab manufactured by continuous casting, it has been attempted to generate a sawtooth-shaped vibration waveform in the mold, in which the rise of the mold is slow and the fall is fast. . Then, such a sawtooth non-sine waveform contains second-order, third-order, and other harmonic components. Under certain vibration conditions, the harmonic components include:
A mechanical support structure such as a beam that supports the entire mold resonates and a predetermined vibration waveform cannot be obtained. This is to prevent this.

[0006]

According to the above conventional construction, the rod position of the hydraulic cylinder and the acceleration of the mold itself are detected, and the detected values are fed back to obtain a predetermined vibration waveform. However, there is a problem that it is difficult to obtain a predetermined vibration waveform because the control target is complicated and the mounting location of the sensor is limited.

Further, in continuous casting equipment, the environmental conditions are poor, so that the sensor is likely to fail. Therefore, if the sensor fails, the hydraulic cylinder runs away, so that the vibration is stopped, that is, the casting is stopped. However, there is a problem that waste is generated due to the need to return the pot or scrap.

Accordingly, an object of the present invention is to provide a mold vibrating apparatus in a continuous casting facility that can solve the above-mentioned problems.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, vibration of a mold in the continuous casting equipment of the present invention includes a support structure for mechanically supporting a mold, and a vibration applied to the mold via the support structure. An electro-hydraulic servo cylinder to be added, a hydraulic unit for supplying hydraulic oil to the electro-hydraulic servo cylinder via a hydraulic circuit, and a control for outputting a drive signal to a servo motor driving the electro-hydraulic servo cylinder The control unit comprises a target waveform signal generating section for generating a target waveform signal for the mold, and a target waveform signal output from the target waveform signal generating section. A first hydraulic system compensation signal generator for adding a cylinder compensation waveform signal for improving waveform disturbance due to the first hydraulic system The waveform signal from the signal generator,
A mechanical compensation signal generator for adding a mechanical compensation waveform signal for canceling a motion transmission delay due to elastic deformation of the support structure, and a target waveform signal from the target waveform signal generator, and A filter circuit for outputting a correction waveform signal for averaging the gain in the frequency characteristic, and a control coefficient in the filter circuit being controlled to an optimum value according to a deviation signal between the target waveform signal and the displacement state signal. An adaptive control circuit unit; a feedback control unit that generates a feedback control signal based on a deviation signal obtained by subtracting a correction waveform signal output from the filter circuit from a displacement state signal from the displacement state detector; And a second hydraulic system compensation signal generator for adding the hydraulic system compensation signal to the feedback control signal from the controller. The one in which the deviation signal output signal is added from the second hydraulic system compensation signal generation unit and so as to be added to the waveform signal output from the mechanical system compensation signal generator.

In the above configuration, the adaptive control circuit section uses an algorithm in an adaptive filter, or uses an analysis technique based on fuzzy inference or fast Fourier transform based on a neural network.

[0011]

According to the above construction, when a predetermined vibration waveform, that is, a target waveform is given to the mold by the electro-hydraulic servo cylinder via the support structure, compensation for canceling the operation delay of the electro-hydraulic servo cylinder is provided. Adopts feedforward control to add a signal and a compensation signal to cancel the motion transmission delay due to elastic deformation of the support structure, and to cancel the resonance due to the actual vibration waveform of the mold and the natural frequency of the mold vibration system In addition to using feedback control to output the difference from the corrected waveform signal as a deviation signal, and when calculating the corrected waveform signal by the filter circuit, the control parameters in the filter circuit are optimized in real time.
The deviation and resonance of the actual vibration waveform of the mold can be reliably corrected.

In addition, since the control parameters of the filter circuit are modified in real time, for example, when the operating characteristics of the electrohydraulic servo cylinder change with time, or when the mold having the same weight and size is replaced, the mold is changed. Even when the natural frequency of the vibration system slightly changes, optimal vibration control can always be performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1 and 2, reference numeral 1 denotes a mold in a continuous casting facility, which is mounted on a table 2. The mold 1 is supported by a table 4 and a link mechanism 3 so as to be swingable with respect to a gantry 4 in a vertical plane, and an electro-hydraulic servo cylinder 5 connected to the link mechanism 3. Vibrated vertically.

That is, the link mechanism 3 comprises an upper link 11 and a lower link 12, one end of each of the upper and lower links 11, 12 is connected to the table 2 by a pin, respectively. The other end and an intermediate portion of the lower link 12 are supported on the gantry 4 side via pins, respectively, and the other end of the lower link 12 is pin-connected to the rod 5a of the servo cylinder 5.

A hydraulic unit 21 for supplying hydraulic oil is connected to the servo cylinder 5 through a hydraulic pipe 22, and hydraulic oil from the hydraulic unit 21 is supplied into the cylinder chamber 23 by a predetermined amount. Spool 2 for
An electric servo motor 25 for moving the servo motor 4 is provided, and a drive unit 26 including a servo amplifier for driving the servo motor 25 is provided.

A control unit 27 for controlling the drive unit 26 of the servo cylinder 5 is provided, and the control unit 27
From a position sensor (displacement state detector) 28 that detects the displacement state of the mold 1, for example, the vibration position, from an actual mold position signal (an example of a displacement state signal.
A signal input unit 31 having an A / D converter for converting the actual position signal into a digital signal, and a first control unit 32 for generating a mold target waveform signal. A second control unit 33 for outputting, to the position signal from the signal input unit 31, a correction waveform signal for smoothing the gain in the frequency characteristic, and a second control unit for outputting the actual position signal of the mold. A subtraction signal is obtained by subtracting the correction waveform signal from the control signal 33, a predetermined feedback control signal is calculated based on the deviation signal, and the feedback control signal is added to the output signal from the first control unit 32. 3 control section 34 and a drive signal to which the output signals from both control sections 32 and 34 are added to output a rotation angle signal to the drive unit 26 side. Servo motor rotation angle converter 35
It is composed of

The first controller 32 includes a target waveform signal generator 41 for generating a target waveform signal for vibrating the mold 1, and a servo cylinder for outputting the target waveform signal output from the target waveform signal generator 41. A first servo cylinder compensation signal generator (first hydraulic system compensation) for adding a compensation waveform signal for improving a waveform disturbance due to an operation delay of 5 (for example, a delay due to valve switching, oil compression, etc.) A signal generation unit) 42 and a mechanical compensation signal generation unit (for example, a mechanical system compensation signal generation unit for adding a compensation waveform signal for canceling a motion transmission delay due to elastic deformation in the mechanical support structure including the link mechanism 3 and the table 2). 43 for performing acceleration compensation of the mold).

The second control section 33 receives the target waveform signal from the target waveform signal generation section 41 and, in accordance with the target waveform signal, corrects the gain in the frequency characteristic of the correction waveform signal. (Specifically, a filter circuit 51 for outputting a waveform signal for canceling a natural frequency of the mold vibration system) is provided, and characteristics of the filter circuit 51, that is, control parameters are changed in real time by an actual mold. An adaptive control circuit section 52 is provided to optimize the operation in accordance with one vibration state. As the filter circuit 51, for example, a target value filter or a notch filter is used.

The adaptive control circuit section 52 receives the real position signal from the signal input section 31, performs a Fourier series expansion such as a fast Fourier transform, and performs a frequency analysis of the real position signal. And an output signal from the waveform diagnosis circuit 53 and a target waveform signal from the target waveform signal generation unit 41, and control parameters (specifically, control parameters) in the filter circuit 51 based on a deviation signal between these two waveform signals. Each coefficient value of control transfer function)
And a learning circuit 54 for setting to an optimum value.

A digital signal processor or the like is used for the learning circuit 54.
For example, the control parameter in the filter circuit 51 is selected such that the original natural frequency is selected from a plurality of peak values mixed in the actual position signal and the natural frequency of the vibration system of the mold 1 can always be canceled. A signal is output in such a manner that the optimum value is obtained in real time. The learning circuit 54 employs an algorithm applied to an adaptive filter or the like.

The learning circuit 54 and the waveform diagnosis circuit 5
3, a learning determination unit 55 for determining whether to use the learning circuit 54 is provided. For example, when a pattern different from the previous waveform signal is input, the learning circuit 5
The signal is output via the line 4.

The third control unit 34 includes the signal input unit 3
And a feedback control unit 61 that inputs a real position signal from the control unit 1 and outputs a feedback control signal (PID control signal) and a feedback compensation signal (for example, a compensation signal based on a speed and a position signal). And a second servo cylinder compensation signal generator (second hydraulic system compensation signal generator) 62 for receiving the position signal thus input and improving waveform disturbance due to the operation delay of the servo cylinder 5. The deviation signal compensated by the second servo cylinder compensation signal generator 62 is added to the target waveform signal on which the hydraulic and mechanical compensation has been performed.

The feedback control unit 61
It comprises a feedback control circuit 63 for performing PID control, and a feedback compensation circuit 64 for outputting a compensation signal based on the speed and position signals. This feedback compensation circuit 64 stabilizes the control system,
This is for improving the control accuracy.

The drive unit 26 includes a D / A converter 71 for converting the rotation angle signal output from the servo motor rotation angle converter 35 into a digital signal,
A servo amplifier 72 for amplifying an output signal from the A-converter 71, and detecting an actual rotation angle of the servo motor 25 from an angle detector 25a provided in the servo motor 25, and detecting the detected rotation angle signal. Is fed back to the control signal input to the servo amplifier 72. The first servo cylinder compensation signal generator 42 and the mechanical system compensation signal generator 43 perform feedforward compensation.

In the above configuration, the target waveform signal output from the target waveform signal generator 41 of the mold 1 is x ₀ , the first servo cylinder compensation signal generator 42 constituting the feedforward compensation circuit and the mechanical system compensation signal generator Part 4
3 are (Δx ₁ ) and (Δx ₁ ), respectively.
x ₂ ) and the deviation signal that is feedback-controlled and compensated by the feedback control unit 61 and the second servo cylinder compensation signal generation unit 62 based on the actual position signal from the signal input unit 31 is (Δx ₀ ). The signal input to the motor rotation angle converter 35 is (x ₀ + Δ
x ₀ + Δx ₁ + Δx ₂ ).

The waveform signal from the signal input unit 31 is
After the frequency analysis is performed by the waveform diagnosis circuit 53 of the second control unit 33, it is input to the learning determination unit 55, where it is determined whether learning is required or not. And
If it is determined that learning is necessary, the waveform signal and the target waveform signal from the target waveform signal generator 41 are input to the learning circuit 54, and a deviation signal between both waveform signals is calculated. The predetermined operation is performed by the algorithm used for the adaptive filter based on
For example, a peak value in a frequency characteristic of an actual waveform signal, that is, a deviation signal between a resonance frequency (natural frequency) and a target waveform signal is obtained, and a waveform signal that cancels the resonance frequency is output based on the deviation signal. Then, the control parameters are output to the filter circuit 51. Accordingly, in the actual vibration state of the mold 1, the filter circuit 51 outputs a correction waveform signal (Δx ₃ ) that cancels out the natural frequency.

Further, in the feedforward compensation circuit section, a compensation signal (Δx ₁ ) for improving the operation delay of the servo cylinder 5 and a compensation for canceling the signal transmission delay based on the elastic deformation in the mechanical support structure. Signal (Δ
x ₂ ) is calculated. The compensation signal (Δx ₁ ),
(Δx ₂ ) is a compensation component theoretically determined so that the mold 1 has the same waveform as a predetermined target vibration waveform, and is a transfer function between the input of the servo cylinder 5 and the output from the mechanical support structure. Can be obtained by the reciprocal of.

Here, the control in the above configuration will be specifically described. First, in the servo cylinder 5, the operation delay of the hydraulic system is compensated. That is, the movement of the rod portion 5a is controlled by controlling the movement of the valve and the spool 24. In order for the rod portion 5a to move at a predetermined speed, it is necessary that the opening degree of the valve be equal to or more than a certain value. Therefore, an operation delay (phase delay) occurs between the input and the output. This operation delay is eliminated, and the input waveform is compensated so that the output waveform of the servo cylinder 5 has the same phase and the same waveform as the predetermined waveform.

Next, since the mechanical support structure is not completely rigid, if the output waveform component of the rod portion 5a of the servo cylinder 5 contains a higher-order component, for example, the mechanical support structure The structure, for example, the link mechanism 3 causes a resonance phenomenon. In particular, when the signal waveform is a non-sine waveform such as a saw-tooth shape, resonance tends to occur because the target waveform signal itself contains a considerably high-order component.

Therefore, the servo cylinder 5 outputs a waveform signal including a signal component that cancels the resonance of the mechanical support structure including the link mechanism 3, the table 2, and the like.

That is, the compensation signal (Δx ₁ ) includes:
A signal component for improving the operation delay generated by the servo cylinder 5 is included, and a compensation signal (Δx ₂ )
A signal component for canceling resonance generated in a mechanical support structure such as the link mechanism 3 and the table 2 is included.

As described above, feedforward compensation is employed, and based on the actual position of the mold 1,
Since feedback control for correcting the deviation from the target waveform signal in real time is also used, for example, a position detection sensor for detecting the position of the rod portion of the hydraulic cylinder as described in the conventional example can be eliminated, and feed The deviation between the actual vibration waveform of the mold 1 and the target waveform, which cannot be eliminated by the forward control alone, can be corrected in real time, and therefore, it is possible to perform control with high resistance to disturbance and very high accuracy.

Further, since a position sensor for detecting the position of the rod portion of the servo cylinder can be dispensed with, the runaway of the servo cylinder which occurs when the position sensor provided on the rod portion of the servo cylinder breaks down, for example, can be eliminated. No need to worry.

In the above embodiment, the mold 1
Although it has been described that the position, speed and acceleration are detected and output as position signals using the position sensor 28, for example, an acceleration sensor may be used and this acceleration signal may be integrated once to obtain a speed signal. Also, the position signal may be obtained by integrating twice, and the acceleration signal may be directly input to the control unit, the speed signal may be used, and the position sensor and the acceleration sensor may be used together. Good.

Further, in the above embodiment, the position sensor (displacement state detector) 28 has been described as being attached to the mold 1, but it may be attached to the table 2 side, for example, and is shown by a virtual line in FIG. As described above, the upper link 3 may be attached to the end. In this case, the waveform of the table estimated from the vibration waveform of the mold is used as the target waveform signal.

By the way, in the above-mentioned embodiment, the adaptive control circuit section has been described to use the algorithm in the adaptive filter. However, for example, instead of using such an algorithm, as shown in FIG. An analysis method using fuzzy inference or fast Fourier transform based on a neural network may be used.

Further, in the above-described embodiment, the mold has been described to be vibrated through the table and the link mechanism. However, for example, a servo cylinder may be directly connected to the table supporting the mold. In this case, a table is considered as a mechanical support structure for signal transmission.

[0038]

As described above, according to the structure of the present invention, when a predetermined vibration waveform, that is, a target waveform is given to the mold by the electro-hydraulic servo cylinder via the support structure, the electro-hydraulic servo cylinder is driven. Adopts feedforward control to add a compensation signal to cancel the operation delay and a compensation signal to cancel the motion transmission delay due to the elastic deformation of the support structure, and furthermore, the actual vibration waveform of the mold and the characteristic of the mold vibration system In addition to using feedback control to output the difference from the corrected waveform signal for canceling the resonance due to the frequency as a deviation signal, the control parameters in the filter circuit are optimized in real time when the corrected waveform signal is calculated by the filter circuit. To ensure that the actual vibration waveform of the mold is shifted and resonated. It can be modified, thus it is possible to perform strong and very good control accuracy disturbance.

Further, in the feedback control, a signal obtained based on the displacement state of the mold is fed back, so that the occurrence of control failure due to a sensor failure is significantly reduced, and the feedback control is performed even if the sensor fails. Even if the function does not work, the vibration control of the mold can be continued by the feedforward compensation, so that the occurrence of scrap and the like due to the stoppage of casting can be prevented.

Further, since the control parameters of the filter circuit are modified in real time, for example, when the characteristics of the electro-hydraulic servo cylinder change over time, or when the mold having the same weight and size is replaced, the vibration of the mold is changed. Even if the natural frequency of the system changes slightly,
Optimal vibration control can always be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic overall configuration of a mold vibration device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an operation of a main part of the mold vibration device according to one embodiment of the present invention.

FIG. 3 is a block diagram showing an operation of a main part of a mold vibration device according to another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mold 2 table 3 link mechanism 5 electro-hydraulic servo cylinder 21 hydraulic unit 25 electric servo motor 26 drive unit 27 control unit 28 position sensor 31 signal input unit 32 first control unit 33 second control unit 34 third control unit 35 servo Motor rotation angle converter 41 Target waveform signal generator 42 First servo cylinder compensation signal generator 43 Mechanical system compensation signal generator 51 Filter circuit 52 Adaptive control circuit 61 Feedback control circuit 62 Second servo cylinder compensation signal generator

──────────────────────────────────────────────────続 き Continuing on the front page (72) Hideki Saito, Inventor Hitachi Zosen Corporation (3-72) 5-28 Nishikujo, Konohana-ku, Osaka-shi, Osaka (72) Inventor Masato Aoki 5-chome, Nishikujo, Konohana-ku, Osaka-shi, Osaka No. 3-28 within Hitachi Zosen Corporation (72) Inventor Shigetoshi Okumura 5-28 Nishikujo, Konohana-ku, Osaka-shi, Osaka-shi Within Hitachi Zosen Corporation (56) References JP-A-7-214265 (JP, A) JP-A-7-116804 (JP, A) JP-A-7-116803 (JP, A) JP-A-7-116802 (JP, A) JP-A-7-116801 (JP, A) JP-A-4 -274855 (JP, A) JP-A-62-137151 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B22D 11/16 105 F15B 9/09 G05B 13/02

Claims (4)

(57) [Claims] 1. A support structure for mechanically supporting a mold, an electro-hydraulic servo cylinder for applying vibration to the mold via the support structure, and a hydraulic fluid for the electro-hydraulic servo cylinder via a hydraulic circuit. And a control unit for outputting a drive signal to the servomotor driving the electro-hydraulic servo cylinder. The control unit includes a target waveform signal for generating a mold target waveform signal. And a first hydraulic system compensation for adding a cylinder compensation waveform signal for improving waveform disturbance due to an operation delay of the electrohydraulic servo cylinder to the target waveform signal output from the target waveform signal generator. The signal generation unit and the waveform signal from the first hydraulic system compensation signal generation unit cancel the motion transmission delay due to the elastic deformation of the support structure. And a correction waveform signal for inputting the target waveform signal from the target waveform signal generation section and averaging the gain in the frequency characteristic. And an adaptive control circuit for controlling a control coefficient in the filter circuit to an optimal value according to a deviation signal between the target waveform signal and the displacement state signal; and a displacement from the displacement state detector. A feedback control unit that generates a feedback control signal based on a deviation signal obtained by subtracting the correction waveform signal output from the filter circuit from the state signal, and a hydraulic system compensation signal is added to the feedback control signal from the feedback control unit. And an output signal from the second hydraulic system compensation signal generator is added. Mold oscillation device deviation signal in the continuous casting plant, characterized in that so as to be added to the waveform signal output from the mechanical system compensation signal generator. 2. The adaptive control circuit unit according to claim 1, wherein an algorithm in an adaptive filter is used.
A mold vibrating device in the continuous casting facility as described in the above. 3. The apparatus according to claim 1, wherein fuzzy inference is used as the adaptive control circuit. 4. The apparatus according to claim 1, wherein an analysis method based on a fast Fourier transform based on a neural network is used as the adaptive control circuit.