Loop control method for preventing spin in finish rolling

Abstract

The application discloses a loop control method for preventing tailing in finish rolling, comprising the following steps: judging whether the upper stand located at the front end of the current stand is throwing steel, and after the upper stand throws steel, controlling the loop angle of the lower loop to decrease by a preset angle; the lower loop is located between the lower stand and the current stand, and the lower loop is located at the rear end of the current stand; obtaining the real-time loop angle change amount of the lower loop; and according to the real-time loop angle change amount, reducing the rolling speed of the current stand to a target speed. The loop control method provided by the application can effectively avoid the phenomenon of rolling off the tail of the strip steel under the double effects of reducing the loop angle and reducing the rolling speed of the current stand after the upper stand throws steel, and the method does not need to increase new equipment or detection elements on the basis of the original equipment and control functions, and through the original control strategy as a judgment condition, the precise control of the loop angle is realized by automatically reducing the speed of the lower stand after the upper stand throws steel.

Description

Technical Field

[0001] This invention relates to the field of metallurgical hot rolling methods, and in particular to a looper control method for preventing tailing during finishing rolling. Background Technology

[0002] Currently, most mainstream hot-rolled wide strip production lines in China have a complete looper control mode. During normal rolling, the looper is in a stable state. However, when the strip is thrown from the upper stand, the back tension disappears and the forward slip increases significantly, resulting in an increase in the metal flow rate per second of the current stand. This causes the looper angle to rise, and the looper angle of the lower stand to rise as well. When the strip is thrown from the current stand, the tail of the strip will float upwards. This is especially true when producing thin specifications below 2.5mm. The rolling speed is fast, the looper angle rises, and the tail of the strip floats up to a height of 30-40cm when the strip is thrown, which seriously deviates from the original rolling line and causes the tail to be crushed.

[0003] After the finishing mill's end stand finishes its tail, roll marks are left on the surface of the rolled piece, necessitating the replacement of the work rolls, causing production interruptions, impacting production efficiency, and increasing production costs. Furthermore, production tracking revealed that manual intervention to control the looper angle during production is frequently employed. However, due to the poor precision of manual control of the looper angle, tail-end steel pulling often occurs, requiring the removal of portions that do not meet product technical requirements, resulting in reduced yield and waste of labor and materials.

[0004] Therefore, how to effectively improve the control accuracy of the looper angle and improve the quality of rolled products is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a looper control method to prevent tailing during finishing rolling, which improves the accuracy of looper angle control, reduces rolling damage, and improves product quality.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A looper control method for preventing tailing during finishing milling, applied in a finishing mill system, the finishing mill system including several stands and loopers, the loopers being located between adjacent stands; comprising the following steps:

[0008] Step S1: Determine whether the upper frame at the front end of the current frame has thrown steel, and after the upper frame throws steel, control the lower looper's looper angle to decrease by a preset angle; the lower looper is located between the lower frame and the current frame, and the lower looper is located at the rear end of the current frame;

[0009] Step S2: Obtain the real-time change in the angle of the lower looper;

[0010] Step S3: Based on the real-time change in looper angle, reduce the rolling speed of the current stand to the target speed.

[0011] Preferably, the step of determining whether the upper frame located at the front end of the current frame is throwing steel includes:

[0012] Based on the changes in the rolling load of the upper stand, determine whether the upper stand is throwing out steel.

[0013] Preferably, before step S1, the method further includes:

[0014] The height of the lower loop is detected using a loop encoder;

[0015] Set a preset descent height, and calculate the preset angle based on the preset descent height.

[0016] Preferably, before step S1, the method further includes:

[0017] Based on the process parameters of each frame, the initial loop angle of each loop is set;

[0018] The step of controlling the reduction of the loop angle of the lower loop by a preset angle includes: controlling the reduction of the loop angle of the lower loop by a preset angle until the loop angle = initial loop angle - preset angle.

[0019] Preferably, the preset angle is 2-4°.

[0020] Preferably, the method further includes the step of:

[0021] Add a "Steel Throwing Speed ​​Intervention" program to the finishing mill control module;

[0022] Add a "Strip Tail Throwing Dynamic Speed ​​Reduction Compensation" interface under the "Speed ​​Compensation" control column of the finishing mill monitoring system, and set up program module links.

[0023] Preferably, the step of reducing the rolling speed of the current stand to the target speed based on the real-time change in looper angle includes:

[0024] Set the speed drop compensation coefficient N and several dynamic speed drop values ​​A;

[0025] Based on the real-time change in the angle of the lower loop, select one of the input dynamic descent values.

[0026] Preferably, after selecting one of the dynamic descent values ​​to input based on the real-time change in the lower looper angle, the step further includes:

[0027] Determine whether the current frame is throwing steel. If the current frame throws steel, control the speed of the current frame to return to the initial speed.

[0028] Preferably, the target speed V of the current rack n =V0-V0*N*A, where V0 is the initial speed of the current rack.

[0029] Preferably, the speed drop compensation coefficient N = 1%, and the dynamic speed drop value A = 1 to 5 (A is an integer).

[0030] The looper control method for preventing tail-wagging in finishing rolling provided by this invention is applied to a finishing rolling system, which includes several stands and loopers, with the loopers located between adjacent stands. The method includes the following steps: Step S1: Determine whether the upper stand at the front of the current stand has thrown steel, and after the upper stand throws steel, control the looper angle of the lower looper to decrease by a preset angle; the lower looper is located between the lower stand and the current stand, and the lower looper is located at the rear end of the current stand; Step S2: Obtain the real-time change in the looper angle of the lower looper; Step S3: Based on the real-time change in the looper angle, reduce the rolling speed of the current stand to a target speed. The looper control method for preventing tail-wagging in finishing milling provided by this invention effectively avoids strip tail-wagging by reducing the looper angle and the rolling speed of the current stand after the strip is thrown out of the upper stand. Furthermore, this method does not require the addition of new equipment or detection elements based on the existing equipment and control functions. It uses the existing control strategy as a judgment condition and achieves precise control of the looper angle by automatically reducing the speed of the lower stand after the strip is thrown out of the upper stand.

[0031] In a preferred embodiment, the step of reducing the rolling speed of the current stand to the target speed based on the real-time change in the looper angle includes: setting a speed reduction compensation coefficient N and several dynamic speed reduction values ​​A; and selecting one of the dynamic speed reduction values ​​based on the real-time change in the lower looper angle. With the above settings, by setting the speed reduction compensation coefficient N and the dynamic speed reduction value A, after the strip is thrown from the upper stand, only the dynamic speed reduction value needs to be quickly selected based on the real-time change in the looper angle to reduce the rolling speed of the current stand by a specific proportion. By adjusting the dynamic speed reduction compensation of the current mill, the height of the looper angle can be controlled, thus maintaining the stability of the strip tail during finishing rolling, preventing strip breakage, and avoiding excessive manual intervention that could lead to strip pulling. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the finishing mill stand and looper;

[0034] Figure 2 A flowchart of a specific embodiment of the looper control method for preventing tailing during finishing milling provided by the present invention;

[0035] Figure 3 This is a schematic diagram of the speed drop compensation control column in the looper control method for preventing tailing during finishing milling provided by the present invention.

[0036] Wherein: 1-Upper rack; 2-Current rack; 3-Lower rack; 4-Upper looper; 5-Lower looper. Detailed Implementation

[0037] The core of this invention is to provide a looper control method to prevent tailing during finishing milling. This method can achieve precise control of the looper angle during steel throwing in finishing milling, improve the stability of steel throwing in finishing milling, and in particular reduce the risk of tailing, reduce labor intensity, and improve production efficiency.

[0038] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Please refer to Figures 1 to 3 , Figure 1 This is a schematic diagram of the structure of the finishing mill stand and looper; Figure 2 A flowchart of a specific embodiment of the looper control method for preventing tailing during finishing milling provided by the present invention; Figure 3 This is a schematic diagram of the speed drop compensation control column in the looper control method for preventing tailing during finishing milling provided by the present invention.

[0040] In this embodiment, the looper control method for preventing tailing during finishing milling is applied to a finishing milling system, which includes several stands and loopers, with the loopers located between adjacent stands.

[0041] The looper control method for preventing tailing during finishing milling includes the following steps:

[0042] Step S1: Determine whether the upper frame 1 located at the front end of the current frame 2 has thrown steel, and after the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle; the lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0043] Step S2: Obtain the real-time change in the angle of the lower loop 5;

[0044] Step S3: Based on the real-time change in looper angle, reduce the rolling speed of the current stand 2 to the target speed.

[0045] Specifically, in the actual rolling control process, when steel is ejected from any stand, the stand that ejected the steel is designated as the upper stand 1, and the stand located behind the upper stand 1 is designated as the current stand 2. Rolling speed control is applied to the current stand 2, and the stand located behind the current stand 2 is designated as the lower stand 3. An upper looper 4 is installed between the upper stand 1 and the current stand 2, and an upper looper 4 is also installed between the lower stand 3 and the current stand 2. Looper angle control is applied to the lower looper 5. In other words, this looper control method involves reducing the looper angle of the upper looper 4 in conjunction with reducing the rolling speed V of the current stand 2. n Under the dual effect, the upper looper 4 is prevented from sliding forward, reducing the problem of the looper angle increasing instead of decreasing due to the disappearance of the rear tension.

[0046] The looper control method for preventing tailing during finishing milling provided by this invention effectively avoids strip tail damage by reducing the looper angle and the rolling speed of the current stand 2 after the strip is thrown out of the upper stand 1. Furthermore, this method does not require the addition of new equipment or detection elements based on the existing equipment and control functions. It uses the existing control strategy as a judgment condition and automatically reduces the speed of the lower stand 3 after the strip is thrown out of the upper stand 1 to achieve precise control of the looper angle.

[0047] In some implementations, the step of determining whether the upper frame 1 located at the front end of the current frame 2 has thrown steel includes: based on the rolling load F of the upper frame 1. n+1 The rolling load of all stands is monitored during the rolling process. When the rolling load of a particular stand changes abruptly, it is determined that the stand has experienced a rolling failure, and that stand is identified as upper stand 1. The stand following upper stand 1 is designated as current stand 2. The process of determining whether upper stand 1 has experienced a rolling failure based on the rolling load change can utilize existing program settings; any method capable of identifying upper stand 1 is acceptable.

[0048] In some implementations, the method prior to step S1 includes:

[0049] The height of the lower loop 5 is detected using a loop encoder;

[0050] Set a preset descent height, and calculate a preset angle based on this height, which is the angle at which the lower loop 5 needs to be lowered. The above steps can be achieved by monitoring the height of the lower loop 5 as a way to determine the loop angle. The ultimate goal of the adjustment process is to adjust the height of the lower loop 5 to prevent it from slipping forward due to the loss of back tension. Since the height of the lower loop 5 changes through the loop angle, the preset angle at which the lower loop 5 needs to tilt during descent can be calculated by monitoring its height and using the target adjustment height.

[0051] In some implementations, the method prior to step S1 includes:

[0052] Based on the process parameters of each frame, set the initial loop angle for each loop;

[0053] The step of controlling the lower looper 5 to reduce the looper angle by a preset angle includes: controlling the lower looper 5 to reduce the looper angle by a preset angle until the looper angle = initial looper angle - preset angle. The initial looper angle is the looper angle of the lower looper 5 when the upper stand 1 is in normal rolling condition, i.e., before the upper stand 1 has discarded steel.

[0054] In some implementations, the preset angle is 2-4°. For example, during normal and stable rolling, when the upper stand 1 throws steel, the loop angle of the lower loop 5 is automatically reduced from the initial loop angle of 23° to 20°.

[0055] In some implementations, the steps also include:

[0056] Add a "Steel Throwing Speed ​​Intervention" program to the finishing mill control module;

[0057] Add a "Strip Tail Throwing Dynamic Speed ​​Reduction Compensation" interface under the "Speed ​​Compensation" control column of the finishing mill monitoring system, and set up program module links.

[0058] Specifically, during normal and stable rolling, when the upper stand 1 throws out the strip, the looper angle of the lower looper 5 is automatically reduced from the initial looper angle to the preset angle. At the same time, the current stand 2 slows down, but the back tension disappears and the forward slip increases, resulting in an increase in the metal flow rate per second of the current stand 2. This causes the looper angle to rise instead of fall. Therefore, "dynamic speed reduction compensation for strip tail throwing" is added to reduce the speed of the current stand 2 to reduce the metal flow rate of the current stand 2 and reduce the strip length between stands to control the looper angle height and achieve the purpose of preventing tail throwing in the finishing mill.

[0059] In some implementations, the step of reducing the rolling speed of the current stand 2 to the target speed based on the real-time change in the looper angle includes:

[0060] Set the speed drop compensation coefficient N and several dynamic speed drop values ​​A;

[0061] Based on the real-time change in the angle of the lower loop 5, select one of the input dynamic descent values.

[0062] The above settings, by setting the speed reduction compensation coefficient N and the dynamic speed reduction value A, allow for a specific reduction in the rolling speed of the current stand 2 by quickly selecting the dynamic speed reduction value based on the real-time change in the looper angle after the strip is thrown from the upper stand 1. By adjusting the dynamic speed reduction compensation of the current mill, the height of the looper angle can be controlled, which can maintain the stability of the strip tail during finishing rolling and prevent the strip from being crushed, while also avoiding the phenomenon of strip pulling caused by excessive manual intervention.

[0063] Specifically, the dynamic speed drop compensation coefficient for strip tail throw is set to [0, 5], that is, the speed drop value is 0-5% of the current stand 2 stable rolling speed reference value. The production worker inputs the corresponding value in the "Strip Tail Throw Dynamic Speed ​​Drop Compensation" module according to the change of looper angle, and controls the actual angle of the looper to the set angle.

[0064] In some implementations, after selecting a dynamic descent value based on the real-time change in the loop angle of the lower loop 5, the step further includes:

[0065] Determine if the current frame 2 has thrown steel. If the current frame 2 throws steel, control the speed of the current frame 2 to restore the initial speed.

[0066] Specifically, after the current stand 2 throws the steel, the speed of the current stand 2 is controlled to restore the initial speed, so as to ensure the smooth progress of subsequent strip rolling.

[0067] In some implementations, the target velocity V of the current rack 2 n =V0-ΔV=V0-V0*N*A, where V0 is the initial velocity of the current rack 2.

[0068] In some implementations, the speed drop compensation coefficient N = 1%, and the dynamic speed drop value A = 1 to 5A, where A is an integer.

[0069] Example 1

[0070] The looper control method for preventing tailing during finishing milling includes the following steps:

[0071] Determine whether the upper frame 1, located at the front end of the current frame 2, has thrown steel. After the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle. The lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0072] Obtain the real-time change in the angle of the lower loop 5;

[0073] Based on the real-time change in looper angle, reduce the rolling speed of the current stand 2 to the target speed.

[0074] Example 2

[0075] The looper control method for preventing tailing during finishing milling includes the following steps:

[0076] Based on the rolling load change of the upper frame 1, it is determined whether the upper frame 1 will throw out steel. After the upper frame 1 throws out steel, the looper angle of the lower looper 5 is controlled to reduce the preset angle. The lower looper 5 is located between the lower frame 3 and the current frame 2, and the lower looper 5 is located at the rear end of the current frame 2.

[0077] Obtain the real-time change in the angle of the lower loop 5;

[0078] Based on the real-time change in looper angle, reduce the rolling speed of the current stand 2 to the target speed.

[0079] Example 3

[0080] The looper control method for preventing tailing during finishing milling includes the following steps:

[0081] The height of the lower loop 5 is detected using a loop encoder;

[0082] Set a preset descent height, and calculate a preset angle based on the preset descent height;

[0083] Determine whether the upper frame 1, located at the front end of the current frame 2, has thrown steel. After the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle. The lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0084] Obtain the real-time change in the angle of the lower loop 5;

[0085] Based on the real-time change in looper angle, reduce the rolling speed of the current stand 2 to the target speed.

[0086] Example 4

[0087] The looper control method for preventing tailing during finishing milling includes the following steps:

[0088] The height of the lower loop 5 is detected using a loop encoder;

[0089] Set a preset descent height, and calculate a preset angle based on the preset descent height;

[0090] Based on the process parameters of each frame, set the initial loop angle for each loop;

[0091] The step controls the reduction of the loop angle of the loop 5 by a preset angle, including: reducing the loop angle of the loop 5 by a preset angle until the loop angle = initial loop angle - preset angle.

[0092] Determine whether the upper frame 1, located at the front end of the current frame 2, has thrown steel. After the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle. The lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0093] Obtain the real-time change in the angle of the lower loop 5;

[0094] Based on the real-time change in looper angle, reduce the rolling speed of the current stand 2 to the target speed.

[0095] Example 5

[0096] The looper control method for preventing tailing during finishing milling includes the following steps:

[0097] Add a "Steel Throwing Speed ​​Intervention" program to the finishing mill control module;

[0098] Add a "Strip Tail Throwing Dynamic Speed ​​Drop Compensation" interface under the "Speed ​​Compensation" control column of the finishing mill monitoring system, and set up program module links.

[0099] Determine whether the upper frame 1, located at the front end of the current frame 2, has thrown steel. After the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle. The lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0100] Obtain the real-time change in the angle of the lower loop 5;

[0101] Based on the real-time change in looper angle, reduce the rolling speed of the current stand 2 to the target speed.

[0102] Example 6

[0103] The looper control method for preventing tailing during finishing milling includes the following steps:

[0104] Determine whether the upper frame 1, located at the front end of the current frame 2, has thrown steel. After the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle. The lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0105] Obtain the real-time change in the angle of the lower loop 5;

[0106] Set the speed drop compensation coefficient N and several dynamic speed drop values ​​A;

[0107] Based on the real-time change in the angle of the lower loop 5, select one of the input dynamic descent values.

[0108] Example 7

[0109] The looper control method for preventing tailing during finishing milling includes the following steps:

[0110] Determine whether the upper frame 1, located at the front end of the current frame 2, has thrown steel. After the upper frame 1 throws steel, control the loop angle of the lower loop 5 to reduce the preset angle. The lower loop 5 is located between the lower frame 3 and the current frame 2, and the lower loop 5 is located at the rear end of the current frame 2.

[0111] Obtain the real-time change in the angle of the lower loop 5;

[0112] Set the speed drop compensation coefficient N and several dynamic speed drop values ​​A;

[0113] Based on the real-time change in the angle of the lower loop 5, select one of the input dynamic descent values;

[0114] Determine if the current frame 2 has thrown steel. If the current frame 2 throws steel, control the speed of the current frame 2 to restore the initial speed.

[0115] Example 8

[0116] The looper control method for preventing tailing during finishing milling includes the following steps:

[0117] The actual height of the looper is detected using a looper encoder.

[0118] The small loop mode control conditions of the finishing mill looper are used as the conditions for controlling the looper angle during steel throwing.

[0119] After the steel is thrown from the upper stand 1, the rolling speed of the current stand 2 is reduced to control the looper angle;

[0120] After the steel is thrown from frame 2, the speed returns to the normal rolling speed reference value.

[0121] Furthermore, the looper angle control is accomplished jointly by the small looper mode and the mill speed reduction; the change value of the looper angle of the lower stand 3 after the upper stand 1 throws steel is judged, the rolling speed of the current stand 2 is reduced, and the looper angle of the lower stand 3 is reduced; the speed intervention coefficient is set according to the magnitude of the speed reduction of the current stand 2, and different speed intervention values ​​are input according to the magnitude of the change in the looper angle, so that the actual looper angle is close to the set angle value.

[0122] This method for preventing tail-waving in the finishing mill involves the following steps: When the production worker observes a significant increase in the looper angle and a risk of tail-waving when steel is thrown out of the finishing mill, the worker enters the corresponding value in the "Dynamic Speed ​​Reduction Compensation for Strip Tail Throw" module under the "Speed ​​Intervention" section of the finishing mill monitoring main screen, clicks "Speed ​​Reduction Confirmation," and adjusts the speed to control the looper angle during steel throwing. Figure 3As shown, the dynamic speed drop value input here is a value between [0, 5]. Inputting this value represents the percentage change in mill speed controlled by the looper angle during finishing rolling, i.e., the dynamic speed drop value of the current stand 2. This value is actually negative. If the input value is 2, the speed of the current stand 2 is 6.0 m / s, and the dynamic speed drop of the current stand 2 is 6 * 2% = 0.12 m / s, that is, the rolling speed of the current stand 2 decreases from 6.0 m / s to 5.88 m / s. The production worker corrects this value according to the actual looper angle to ensure that the actual looper angle is close to the set angle, while avoiding tail-end steel pulling caused by an excessively large dynamic speed drop input value.

[0123] In other words, this control method, by precisely controlling the looper angle during finishing rolling, not only solves the tail-wagging problem during finishing rolling but also eliminates the tail-wagging issue caused by excessive manual intervention, thus improving production stability.

[0124] The above provides a detailed description of the looper control method for preventing tailing during finishing milling provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A looper control method for preventing tailing during finishing milling, applied in a finishing milling system, the finishing milling system comprising several stands and loopers, the loopers being located between adjacent stands; characterized in that, Includes the following steps: Step S1: Determine whether the upper frame (1) located at the front end of the current frame (2) throws steel, and after the upper frame (1) throws steel, control the loop angle of the lower loop (5) to reduce the preset angle; the lower loop (5) is located between the lower frame (3) and the current frame (2), and the lower loop (5) is located at the rear end of the current frame (2); Step S2: Obtain the real-time change in the loop angle of the lower loop (5); Step S3: Based on the real-time change in looper angle, reduce the rolling speed of the current stand (2) to the target speed; It also includes the following steps: Add a "Steel Throwing Speed ​​Intervention" program to the finishing mill control module; Add a "Strip Tail Throw Dynamic Speed ​​Drop Compensation" interface under the "Speed ​​Compensation" control column of the finishing mill monitoring system, and set up program module links; The step of reducing the rolling speed of the current stand (2) to the target speed based on the real-time change in the looper angle includes: Set the speed drop compensation coefficient N and several dynamic speed drop values ​​A; Based on the real-time change in the loop angle of the lower loop (5), select one of the dynamic descent values ​​to input; Set the dynamic speed drop compensation coefficient for strip tail throwing, that is, the speed drop value is 0-5% of the speed reference value when the current stand (2) is rolling stably. The production worker inputs the corresponding value in the "Dynamic Speed ​​Drop Compensation for Strip Tail Throw" module according to the change of the looper angle, and controls the actual angle of the looper to be within the set angle. After selecting one of the dynamic descent values ​​to input based on the real-time change in the loop angle of the lower loop (5), the step further includes: Determine whether the current frame (2) throws steel. If the current frame (2) throws steel, control the speed of the current frame (2) to return to the initial speed. The target speed V of the current rack (2) n =V0-V0*N*A, where V0 is the initial speed of the current rack (2); the speed drop compensation coefficient N=1%, and the dynamic speed drop value A=1~5, where A is an integer.

2. The looper control method for preventing tail-wagging during finishing rolling according to claim 1, characterized in that, The step of determining whether the upper frame (1) located at the front end of the current frame (2) is throwing steel includes: Based on the change in rolling load of the upper frame (1), determine whether the upper frame (1) is throwing steel.

3. The looper control method for preventing tail-wagging during finishing rolling according to claim 1, characterized in that, Before step S1, the method further includes: The height of the lower loop (5) is detected using a loop encoder; Set a preset descent height, and calculate the preset angle based on the preset descent height.

4. The looper control method for preventing tailing during finishing rolling according to claim 3, characterized in that, Before step S1, the method further includes: Based on the process parameters of each frame, the initial loop angle of each loop is set; The step of controlling the lower loop (5) to reduce the loop angle by a preset angle includes: controlling the lower loop (5) to reduce the loop angle by a preset angle until the loop angle = initial loop angle - preset angle.

5. The looper control method for preventing tailing during finishing rolling according to claim 4, characterized in that, The preset angle is 2-4°.

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