Control method for non-sinusoidal hydraulic vibration curve of mold

Abstract

A control method for a non-sinusoidal hydraulic vibration curve of a mold, relating to the technical field of automation in metallurgical continuous casting. A three-segment linear-sinusoidal composite function is used, wherein one vibration cycle of a position curve thereof comprises three stages: the first stage is a sine-like curve obtained by superimposing a standard sinusoidal function having an angular velocity ω1 with a linear function having a slope (I), the second stage is a sine-like curve obtained by superimposing a standard sinusoidal function having an angular velocity ω2 with a linear function having a slope (II) and an offset (III), and the third stage is a sine-like curve obtained by superimposing a standard sinusoidal function having an angular velocity ω1 and a linear function having a slope (IV) and an offset (V) and connected to the sine-like curve of the first stage at different sampling moments. The method optimizes a non-sinusoidal vibration curve, and achieves a smooth and stable velocity curve for hydraulic cylinder motion, a small peak value, and continuous and smooth acceleration transitions without sudden changes. The control method is simple and easy to implement, has few control parameters, and is convenient to operate.

Description

Control method of non-sinusoidal hydraulic vibration curve of crystallizer Technical Field

[0001] This invention belongs to the field of metallurgical continuous casting automation technology, and relates to a method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer. Background Technology

[0002] High-efficiency continuous casting is the main direction of modern continuous casting technology development, encompassing high casting speed, high quality, high operating rate, and high-temperature hot charging. High casting speed is one of the main hallmarks of modern continuous casting technology development. However, high casting speed increases friction between the billet and the crystallizer, leading to quality or production accidents such as billet cracking and leakage. Therefore, on the one hand, suitable protective slag for high-speed casting is added; on the other hand, a crystallizer vibration mode adapted to high-speed casting is adopted. Non-sinusoidal vibration is a new crystallizer vibration technology developed to meet the needs of high-speed casting. To meet the demands of continuous casting production, the ideal non-sinusoidal vibration curve should have characteristics such as low upper vibration velocity, high lower vibration velocity, short negative slip time, continuous and smooth velocity curve, and stable acceleration changes. However, existing non-sinusoidal vibration modes all have some problems, such as abrupt acceleration changes, limited skewness, and complex models. To improve billet quality and reduce impact on equipment, a new type of non-sinusoidal crystallizer vibration mode needs to be proposed to improve the vibration waveform, increase production efficiency, and reduce production costs. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a control method for the non-sinusoidal hydraulic vibration curve of a crystallizer. This method optimizes the non-sinusoidal vibration curve, realizes a smooth and stable cylinder motion speed curve with small peak values, and continuous, smooth, and abrupt acceleration changes. The control method is simple, easy to implement, and has few control parameters, making it easy to operate.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer employs a three-segment linear-sinusoidal composite function. One vibration cycle of the position curve comprises three stages: the first stage is a standard sine function with an angular velocity of ω1 and a slope of... The quasi-sine curve obtained by superimposing and composing linear functions, the second stage is a standard sine function with an angular velocity of ω2 and a slope of Offset is The quasi-sine curve obtained by superimposing and composing linear functions, the third stage is a standard sine function with angular velocity ω1 and a slope of Offset is The sinusoidal curve obtained by superimposing and composing linear functions connects with the sinusoidal curve of the first stage at different sampling times.

[0006] As can be seen from the continuous cycle period, this function is obtained by connecting a sinusoidal curve obtained by superimposing and transforming a standard sine curve with angular velocities of ω1 and ω2 with a linear function of different slopes. The position curve equation of the non-sinusoidal vibration curve is as follows:

[0007] in,

[0008] ω1 and ω2 are the angular velocities of two standard sine curves, with corresponding vibration periods T1 and T2, respectively, in ms; t is the sampling time of the vibration curve in ms, and a is the steady rise time of the vibration curve in ms, and T2 = aT1.

[0009] The vibration velocity curve equation for a certain period corresponding to the non-sinusoidal vibration curve equation is as follows:

[0010] Therefore, based on the above vibration velocity curve equation and the principle of extreme values, the times corresponding to the minimum and maximum vibration positions within one period, i.e., the moments when the vibration velocity equals 0, can be determined. This can be obtained from the following formula:

[0011] have to

[0012] in:

[0013] t min The unit is ms, which is the time corresponding to the minimum vibration position within one cycle.

[0014] t max The unit is milliseconds (ms), which is the time corresponding to the maximum vibration position within one cycle.

[0015] Vibration skewness is defined as the proportion of the difference between the times when the slope of the vibration curve is positive and the times when the slope is negative within one vibration cycle to the entire vibration cycle. Therefore, the skewness of a non-sinusoidal vibration curve is calculated as follows:

[0016] Where T = T1 + T2 is the time of one vibration period, in milliseconds (ms).

[0017] As can be seen from the above formula, the skewness of the non-sinusoidal vibration curve is only related to the ratio of the vibration period parameters T1 and T2.

[0018] The equation for the vibration acceleration curve corresponding to a certain period of the non-sinusoidal vibration curve equation is as follows:

[0019] As can be seen from the above formula, the vibration acceleration curve consists of three standard sine curves that connect at the edge of the range. As can be seen from the above function, the acceleration of the vibration curve changes gradually and is a smooth curve without abrupt changes.

[0020] The beneficial effects of this invention are as follows:

[0021] 1) The non-sinusoidal vibration curve composed of a three-segment linear-sinusoidal composite function has a longer rise time and a faster fall speed, which can effectively improve the utilization rate of protective slag, enhance the lubrication effect of the crystallizer, and reduce steel leakage accidents. In addition, the vibration speed of the above non-sinusoidal vibration curve is smooth and stable, and the speed peak is reduced. It also ensures that the change of vibration acceleration is more gradual, smooth and continuous without abrupt changes, which minimizes the impact and damage to the equipment and is very friendly to the equipment, effectively extending the service life of the vibration equipment.

[0022] (2) The vibration control method is realized by combining the above non-sinusoidal vibration curve equation. Its parameter setting is simple and can be changed with any process value. Therefore, the above vibration waveform can be applied to slab, flat billet, small square billet continuous casting machine, etc. It is simple to implement, has a wide range of applications, and is highly practical.

[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0025] Figure 1 is a position curve diagram of one cycle of the vibration method provided in an embodiment of the present invention;

[0026] Figure 2 shows the vibration velocity curve of one cycle of the vibration method provided in the embodiment of the present invention;

[0027] Figure 3 shows the vibration acceleration curve of one cycle of the vibration method provided in the embodiment of the present invention;

[0028] Figure 4 shows the vibration curves of the vibration method provided in the embodiment of the present invention for multiple cycles;

[0029] Figure 5 shows the position curves of the vibration method provided in the embodiment of the present invention at different deflection rates;

[0030] Figure 6 shows the velocity curves of the vibration method provided in the embodiment of the present invention at different deflection rates;

[0031] Figure 7 shows the acceleration curves of the vibration method provided in the embodiment of the present invention at different skew rates. Detailed Implementation

[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0033] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0034] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0035] Please refer to Figures 1 to 7. This invention provides a method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer. It employs a three-segment linear-sinusoidal composite function, where one vibration cycle of the position curve comprises three stages: the first stage is a standard sine function with an angular velocity of ω1 and a slope of... The quasi-sine curve obtained by superimposing and composing linear functions, the second stage is a standard sine function with an angular velocity of ω2 and a slope of Offset is The quasi-sine curve obtained by superimposing and composing linear functions, the third stage is a standard sine function with angular velocity ω1 and a slope of Offset is The sinusoidal curve obtained by superimposing and composing linear functions connects with the sinusoidal curve of the first stage at different sampling times.

[0036] As can be seen from the continuous cycle period, this function is obtained by connecting a sinusoidal curve obtained by superimposing and transforming a standard sine curve with angular velocities of ω1 and ω2 with a linear function of different slopes. The position curve equation of the non-sinusoidal vibration curve is as follows:

[0037] in,

[0038] ω1 and ω2 are the angular velocities of two standard sine curves, with corresponding vibration periods T1 and T2, respectively, in ms; t is the sampling time of the vibration curve in ms, and a is the steady rise time of the vibration curve in ms, and T2 = aT1.

[0039] The vibration velocity curve equation for a certain period corresponding to the non-sinusoidal vibration curve equation is as follows:

[0040] Therefore, based on the above vibration velocity curve equation and the principle of extreme values, the times corresponding to the minimum and maximum vibration positions within one period, i.e., the moments when the vibration velocity equals 0, can be determined. This can be obtained from the following formula:

[0041] have to

[0042] in:

[0043] t min The unit is ms, which is the time corresponding to the minimum vibration position within one cycle.

[0044] t max The unit is milliseconds (ms), which is the time corresponding to the maximum vibration position within one cycle.

[0045] Vibration skewness is defined as the proportion of the difference between the times when the slope of the vibration curve is positive and the times when the slope is negative within one vibration cycle to the entire vibration cycle. Therefore, the skewness of a non-sinusoidal vibration curve is calculated as follows:

[0046] Where T = T1 + T2 is the time of one vibration period, in milliseconds (ms).

[0047] As can be seen from the above formula, the skewness of the non-sinusoidal vibration curve is only related to the ratio of the vibration period parameters T1 and T2.

[0048] The equation for the vibration acceleration curve corresponding to a certain period of the non-sinusoidal vibration curve equation is as follows:

[0049] As can be seen from the above formula, the vibration acceleration curve consists of three standard sine curves that connect at the edge of the range. As can be seen from the above function, the acceleration of the vibration curve changes gradually and is a smooth curve without abrupt changes.

[0050] In this embodiment, the specific implementation steps are as follows:

[0051] 1) Set the vibration amplitude H to 4mm and the vibration frequency to 150 times / min, that is, the vibration period T is 400ms;

[0052] 2) Based on the above basic parameters, set the skewness of the vibration curve s = 20%, which corresponds to T1 = 276 ms and T2 = 124 ms, thereby obtaining the angular velocity. angular velocity

[0053] 3) Based on the above parameters and the formula derivation, the position curve, vibration velocity curve, and vibration acceleration curve of one cycle of vibration are obtained, as shown in Figures 1, 2, and 3.

[0054] 4) Through the cyclic vibration process, the vibration position, velocity, and acceleration curves for multiple cycles are obtained, as shown in Figure 4;

[0055] 5) Return to step 2), keeping the oscillation period constant, and change the skewness. Set s to 0%, 10%, and 20% respectively. The corresponding T1 values ​​are 400ms, 320ms, and 276ms, and the corresponding T2 values ​​are 0ms, 80ms, and 124ms. Therefore, the corresponding angular velocities ω1 are... Angular velocity ω2 corresponds to 0, Then, perform steps 3) to 4) in sequence to obtain the corresponding vibration position, velocity, and acceleration curves, as shown in Figures 5, 6, and 7.

[0056] As shown in the above embodiments, the non-sinusoidal vibration position curve is smooth and stable, and the parameter settings can be changed according to any process value. The velocity curve shows that the velocity change is small during the upward vibration process, rising smoothly and steadily for most of the time, with a slight decrease in velocity at one point, reducing the peak velocity. This significantly reduces the friction between the crystallizer and the billet, improving vibration stability. During the downward vibration process, the crystallizer velocity changes rapidly and smoothly in a quasi-sinusoidal manner, significantly reducing the negative slip time. Furthermore, the acceleration curve shows that the acceleration change is continuous and smooth without abrupt changes, greatly reducing the impact and damage to the equipment, making it very equipment-friendly and effectively extending its service life.

[0057] In summary, the control method for the non-sinusoidal hydraulic vibration curve of the crystallizer achieves a smooth and stable cylinder motion speed curve, continuous acceleration changes without abrupt changes, and its control parameters can be changed according to any process value. The skewness can be arbitrarily selected within 20%. It is simple to implement, has a wide range of applications, and is highly practical.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer, characterized in that: Using a three-segment linear-sine composite function, one oscillation period of its position curve consists of three stages: the first stage is a standard sine function with an angular velocity of ω1 and a slope of The quasi-sine curve obtained by superimposing and composing linear functions, the second stage is a standard sine function with an angular velocity of ω2 and a slope of Offset is The quasi-sine curve obtained by superimposing and composing linear functions, the third stage is a standard sine function with angular velocity ω1 and a slope of Offset is The sinusoidal curve obtained by superimposing and composing linear functions connects with the sinusoidal curve of the first stage at different sampling times.

2. The method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer according to claim 1, characterized in that: As can be seen from the continuous cycle, the three-segment linear-sine composite function is a function obtained by connecting the standard sine curves with angular velocities of ω1 and ω2 and linear functions with different slopes to form a quasi-sine curve.

3. The method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer according to claim 2, characterized in that: The position curve equation of the non-sinusoidal vibration curve is as follows: in, ω1 and ω2 are the angular velocities of two standard sine curves, with corresponding vibration periods T1 and T2, respectively, in ms; t is the sampling time of the vibration curve in ms, and a is the steady rise time of the vibration curve in ms, and T2 = aT1.

4. The method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer according to claim 3, characterized in that: The vibration velocity curve equation for a certain period corresponding to the non-sinusoidal vibration curve equation is as follows:

5. The method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer according to claim 4, characterized in that: Based on the above vibration velocity curve equation and the principle of extreme values, the time corresponding to the minimum and maximum vibration positions within one cycle can be calculated, i.e., the moment when the vibration velocity is equal to 0. It can be obtained from the following formula: Find: have to in: t min The time corresponding to the minimum vibration position within one period, in milliseconds; t max The unit is milliseconds (ms), which is the time corresponding to the maximum vibration position within one cycle.

6. The method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer according to claim 5, characterized in that: Vibration skewness is defined as the proportion of the difference between the times when the slope of the vibration curve is positive and the times when the slope is negative within one vibration cycle to the entire vibration cycle. Therefore, the skewness of a non-sinusoidal vibration curve is calculated as follows: Where T = T1 + T2 is the time of one vibration period, in milliseconds (ms). As can be seen from the above formula, the skewness of the non-sinusoidal vibration curve is only related to the ratio of the vibration period parameters T1 and T2.

7. The method for controlling the non-sinusoidal hydraulic vibration curve of a crystallizer according to claim 6, characterized in that: The equation for the vibration acceleration curve corresponding to a certain period of the non-sinusoidal vibration curve equation is as follows: As can be seen from the above formula, the vibration acceleration curve consists of three standard sine curves that connect at the edge of the range. As can be seen from the above function, the acceleration of the vibration curve changes gradually and is a smooth curve without abrupt changes.

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