A method for preventing resonance in a non-sinusoidal vibration system of a continuous casting mold

Abstract

The present invention discloses a method for preventing resonance in a non-sinusoidal vibration system of a continuous casting mold, which is applied to the control system of the continuous casting mold and includes the following steps: synchronous function calculation: calculating the frequency, amplitude, and skew factor of the vibration trajectory curve according to the vibration system parameters set by the continuous casting operator; calculating the range of exciting harmonic orders. Through the non-sinusoidal vibration system of the mold of the present invention, the exciting harmonic components of the vibration curve can be efficiently identified, and while maintaining the original vibration frequency, the exciting harmonic components can be effectively reduced, equipment resonance can be reduced, and the problems of severe jitter and large yaw of the vibration equipment can be effectively solved. When the non-sinusoidal vibration system of the mold detects that equipment resonance is about to be excited, it can automatically adjust the vibration curve parameters to reduce the exciting harmonic components and eliminate resonance without changing the natural frequency of the vibration equipment, greatly reducing the transformation cost of solving the resonance problem. The present invention is applicable to any form of non-sinusoidal vibration system of the mold.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting mold technology, and specifically, to a method for preventing resonance in a non-sinusoidal vibration system of a continuous casting mold. Background Art

[0002] With the development and wide application of the vibration control technology of continuous casting molds, the mold vibration system has greatly increased the lubrication of the mold, improved the surface quality of the cast slab, and enhanced the demolding efficiency of the cast slab, becoming an indispensable part of continuous casting production.

[0003] In continuous casting production, each time the casting machine starts pouring, as the drawing speed increases, the vibration frequency of the mold vibration system will gradually increase from the starting vibration frequency to the working vibration frequency. There will be a resonance phenomenon where the entire vibration equipment shakes violently and the yaw surges within a certain vibration frequency range, resulting in production problems such as the shaking of the molten steel surface and steel leakage.

[0004] The occurrence of this phenomenon is mainly affected by the exciting harmonic components of the vibration curve. Usually, the vibration frequency of the continuous casting mold is lower than the natural frequency of the vibration equipment, and at the same time, the frequency of the exciting harmonic components of the vibration curve is an integer multiple of the vibration frequency. When the frequencies of some vibration curve exciting harmonic components with larger amplitudes are close to or coincide with the natural frequency of the vibration equipment, the vibration equipment will resonate, causing problems such as violent shaking and increased yaw of the vibration system.

[0005] Currently, there are relatively few means to solve the resonance problem of vibration equipment on site. It is often necessary to replace the springs of the vibration equipment or add weight to the vibration equipment to change the natural frequency of the vibration equipment, thereby improving the resonance problem of the vibration equipment. This method of changing the natural frequency of the vibration equipment not only increases the cost but also is not conducive to the maintenance of the equipment.

[0006] To solve the equipment resonance, it is also possible to change the vibration curve through the vibration control system, thereby changing the frequency and amplitude of the exciting harmonic components of the vibration curve and effectively reducing the equipment resonance. This can change the resonance problem of the equipment without increasing the cost and is also conducive to the maintenance of the equipment. However, how to efficiently and stably identify the exciting harmonic components of the vibration curve and automatically adjust the operation of the vibration parameters is an urgent problem to be solved. Summary of the Invention

[0007] In view of the above technical problems in the related art, the present invention provides a method for preventing resonance in a non-sinusoidal vibration system of a continuous casting mold, which can overcome the above-mentioned deficiencies of the prior art.

[0008] To achieve the above technical objectives, the technical solution of the present invention is realized as follows:

[0009] A method for preventing resonance in a non-sinusoidal vibration system of a continuous casting mold, which is applied to the control system of the continuous casting mold, includes the following steps:

[0010] S1: Synchronous function calculation: Calculate the frequency f, amplitude A, and skew factor α of the vibration trajectory curve according to the vibration system parameters set by the continuous casting operator.

[0011] S2 Calculation of the excitation harmonic order range: Calculate the range of the excitation harmonic order N through the natural frequency f of the equipment given by the vibration equipment designer n and the set vibration frequency f.

[0012] S3 Calculation of the excitation harmonic amplitude: Obtain the excitation harmonic amplitude A within the range of the excitation harmonic order N by expanding the Fourier series of the vibration curve N ;

[0013] S4 Comparison of the excitation harmonic amplitudes: Compare the excitation harmonic amplitude A N with the resonance warning amplitude A a If it exceeds the warning value, the vibration system adjusts the parameters and then returns to S3 for calculation; if it is lower than the warning value, the vibration system sends the vibration parameters to S5 for position waveform calculation and output.

[0014] S5 Adjust the vibration parameters: Automatically adjust the vibration parameters to reduce the excitation harmonic amplitude.

[0015] S6 Waveform curve calculation and output: Perform waveform generation calculation through the vibration parameters adjusted in S5 and output them as position set values.

[0016] Furthermore, the vibration system parameters in S1 include the casting speed Vc and the vibration parameters C1 - C5.

[0017] Furthermore, the formula for calculating the range of the excitation harmonic order N in S2 is:

[0018] A * f n / f < N < B * f n / f

[0019] where A and B are excitation frequency range coefficients, and n is a positive integer, determined according to the harmonic resonance interval.

[0020] Furthermore, the formula for solving the excitation harmonic amplitude A by expanding the Fourier series is: N Formula:

[0021]

[0022] where a N and b N are the amplitudes of the N - th order Fourier series expansion.

[0023] Furthermore, the methods for adjusting the vibration parameters in S5 include reducing the skew factor α and reducing the amplitude A.

[0024] Advantages of the present invention: Through the non-sinusoidal vibration system of the mold of the present invention, the exciting harmonic components of the vibration curve can be efficiently identified, and while maintaining the original vibration frequency, the harmonic exciting components can be effectively reduced, the equipment resonance can be reduced, and the problems of severe jitter and large yaw of the vibration equipment can be effectively solved. When the non-sinusoidal vibration system of the mold detects that the equipment resonance is about to be excited, it can automatically adjust the vibration curve parameters to reduce the exciting harmonic components and eliminate the resonance, without changing the natural frequency of the vibration equipment, greatly reducing the transformation cost of solving the resonance problem. The present invention is applicable to any form of non-sinusoidal vibration system of the mold. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a flowchart of the anti-resonance method for the non-sinusoidal vibration system of the continuous casting mold according to the embodiment of the present invention. Detailed Embodiments

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0028] As Figure 1 shown, the anti-resonance method for the non-sinusoidal vibration system of the continuous casting mold according to the embodiment of the present invention is mainly applied to the control system of the continuous casting mold. Different from the existing method of changing the natural frequency of the vibration equipment, the present invention can realize the efficient identification of the harmonic components of the vibration curve and the automatic adjustment of the vibration parameters, effectively reducing the generation of resonance of the vibration equipment. The system block diagram is as Figure 1 shown, and the specific implementation plan is divided into the following steps:

[0029] Step 1: Synchronous function calculation: According to the vibration system parameters set by the continuous casting operator, calculate the frequency f, amplitude A, and skew factor α of the vibration trajectory curve.

[0030] Step 2: Calculation of the excitation harmonic order range: Calculate the range of the excitation harmonic order N based on the natural frequency fn of the device given by the vibration device designer and the set vibration frequency f. This step is mainly used to find the range of excitation harmonic orders that will cause resonance and reduce the amount of data calculation for the excitation harmonic amplitude.

[0031] Step 3: Calculation of the excitation harmonic amplitude: By performing a Fourier series expansion on the vibration curve, obtain the excitation harmonic amplitude AN within the range of the excitation harmonic order N. Different excitation harmonic orders correspond to different AN values.

[0032] Step 4: Comparison of the excitation harmonic amplitudes: Compare the excitation harmonic amplitude AN with the resonance warning amplitude Aa. If it exceeds the warning value, the vibration system adjusts the parameters and then returns to Step 3 for calculation; if it is lower than the warning value, the vibration system sends the vibration parameters to Step 6 for position waveform calculation and output.

[0033] Step 5: Adjustment of the vibration parameters: Achieve the effect of reducing the excitation harmonic amplitude by automatically adjusting the vibration parameters.

[0034] Step 6: Calculation and output of the waveform curve: Perform waveform generation calculation based on the vibration parameters adjusted in Step 5 and output it as the position set value.

[0035] The set curve position value calculated by the above method will effectively reduce the excitation harmonics and eliminate the resonance of the device.

[0036] To facilitate the understanding of the above technical solution of the present invention, the above technical solution of the present invention will be described in detail below through specific usage methods.

[0037] In specific use, during the non-sinusoidal vibration process of the continuous casting mold, the vibration device needs to act according to the set position curve and complete the anti-resonance calculation, and the following steps need to be executed:

[0038] First step, after the vibration control system obtains the casting speed Vc and the vibration parameters C1 to C5, use the synchronization function to calculate the amplitude A, the vibration frequency f, and the skew factor α.

[0039] Second step, the range of the excitation harmonic order can be calculated through the vibration frequency f and the natural frequency fn of the device, which can reduce the range of searching for the excitation harmonics. The calculation is as shown in formula (1)

[0040] A*f n / f < N < B*f n / f (1)

[0041] Among them, A and B are excitation frequency range coefficients, and N is an integer determined according to the harmonic resonance interval.

[0042] Step 3: Solve the exciting harmonic amplitude \(A_N\) through Fourier series expansion, as shown in formula (2).

[0043]

[0044] where \(a\) N and \(b\) N are the amplitudes of the \(N\)-th order Fourier series expansion.

[0045] Step 4: Compare the calculated \(A_N\) with the resonance warning value \(A_a\). If it exceeds the warning value, the vibration control system will jump to Step 5 for processing. If it is lower than the warning value, the vibration control system will jump to Step 6 for processing.

[0046] Step 5: Reduce the exciting harmonic amplitude by reducing the skew factor \(\alpha\) or the amplitude \(A\).

[0047] Step 6: Perform waveform generation calculation on the vibration frequency \(f\), amplitude \(A\), and skew factor \(\alpha\) adjusted in Step 5, and output them as the position setting values.

[0048] Using the method of the present invention, it is possible to reduce the amplitude of the exciting harmonic components of the non-sinusoidal vibration system of the continuous casting mold, eliminate the resonance of the vibration equipment, and reduce the jitter and yaw of the equipment.

[0049] In summary, with the above technical solution of the present invention, the non-sinusoidal vibration system of the mold can efficiently identify the exciting harmonic components of the vibration curve, and effectively reduce the harmonic exciting components while maintaining the original vibration frequency, reduce the equipment resonance, and effectively solve the problems of severe jitter and large yaw of the vibration equipment. When the non-sinusoidal vibration system of the mold detects that the equipment resonance is about to be excited, it can automatically adjust the vibration curve parameters to reduce the exciting harmonic components and eliminate the resonance without changing the natural frequency of the vibration equipment, greatly reducing the transformation cost of solving the resonance problem. The present invention is applicable to any form of non-sinusoidal vibration system of the mold.

[0050] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preventing resonance in a non-sinusoidal vibration system of a continuous casting mold, characterized in that, The control system applied to the continuous casting mold includes the following steps: S1: Synchronous function calculation: According to the vibration system parameters set by the continuous casting operator, calculate the frequency f, amplitude A, and skew factor α of the vibration trajectory curve; Calculation of the range of S2 excitation harmonic orders: Calculate the range of the excitation harmonic order N based on the natural frequency f of the equipment provided by the vibration equipment designer n and the set vibration frequency f; The range calculation formula of the excitation harmonic order N in S2 is: A*f n / f < N < B*f n / f Among them, A and B are excitation frequency range coefficients, and n is a positive integer, determined according to the harmonic resonance interval; Calculation of the excitation harmonic amplitude of S3: By performing Fourier series expansion on the vibration curve, the excitation harmonic amplitude A within the range of the excitation harmonic order N is obtained N ; S4 Excitation Harmonic Amplitude Ratio Comparison: The excitation harmonic amplitude A N is compared with the resonance warning amplitude A a If it exceeds the warning value, the vibration system adjusts the parameters and then returns to S3 for calculation; if it is lower than the warning value, the vibration system sends the vibration parameters to S5 for position waveform calculation and output; S5 Adjust vibration parameters: Automatically adjust the vibration parameters to reduce the excitation harmonic amplitude; S6 Waveform curve calculation and output: Perform waveform generation calculation with the vibration parameters adjusted in S5 and output as the position set value.

2. The anti-resonance method for the non-sinusoidal vibration system of the continuous casting mold according to claim 1, characterized in that, The vibration system parameters in S1 include the casting speed Vc and the vibration parameters C1 to C5.

3. The anti-resonance method for the non-sinusoidal vibration system of a continuous casting mold according to claim 1, wherein, Solving the excitation harmonic amplitude A by Fourier series expansion N The formula is as follows: where a N and b N are the amplitudes of the N - order Fourier series expansion.

4. The anti-resonance method for the non-sinusoidal vibration system of the continuous casting mold according to claim 1, characterized in that, The methods for adjusting the vibration parameters in S5 include reducing the skew factor α and reducing the amplitude A.

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