A method for precise tracking and calculation at the end of a seamless steel tube hot continuous rolling process

Abstract

This invention provides a method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes, relating to the field of mechanical automation control technology. The method first acquires the continuous rolling mill equipment parameters, steel pipe continuous rolling process parameters, and signal transmission time; determines the tail-end tracking start time based on the continuous rolling process parameters; establishes a real-time position calculation method for the tail end of the rough tube based on the speed relationship between the rolls and the steel pipe; combines the steel ejection signals from each stand to form a tail-end tracking deviation index; if the index meets the accuracy requirements, position tracking prediction and compensation are performed on the next support steel pipe; if the accuracy requirements are not met, a stand segment deviation table and deviation grading judgment rules are formed, the problematic stand is located, and global or local parameter corrections are performed. This invention solves the problem of the inability to perform real-time tail-end tracking during the continuous rolling process of seamless steel pipes, enabling the calculation and prediction of the arrival time and position of the steel pipe tail at each stand, and establishing a rule system to determine accuracy.

Description

Technical Field

[0001] This invention relates to the field of mechanical automation control technology, and in particular to a method for precise tracking calculation of the tail end of the hot continuous rolling process of seamless steel pipe. Background Technology

[0002] In the current hot continuous rolling production process of seamless steel pipes, due to the high temperature, high speed and continuous deformation, there is a lack of effective means to monitor the real-time position of the tail of the steel pipe and the accurate time of arrival at each stand. Inaccurate tail tracking often leads to abnormal thinning at the tail and deviations in the sawing position, which greatly affects the uniformity of steel pipe wall thickness and the quality compliance rate.

[0003] In actual hot continuous rolling of steel pipes, certain batches require thinning during rolling to suppress the thickening at the tail end of the pipe, ensuring that the final finished pipe meets quality requirements. On-site tracking of the tail end of the rolling mill is generally done manually based on experience. This method relies on operators' rolling experience, monitoring footage, and the timing of the first few strips being discarded to determine the timing of the tail rolling. However, this method has the following drawbacks:

[0004] (0) The tracking parameters depend on the operator's experience, lack a unified calculation basis, and different people have different judgment standards, which is highly subjective; (1) When judging the timing of the tail rolling in actual field based on experience, it is necessary to wait for the first few rolls of the batch to be rolled for reference, so it is impossible to make online correction for the whole batch. (2) The error of human experience is large, which can easily lead to the rolling process being advanced or delayed, and cannot fully cover the thickened area at the end.

[0005] In summary, existing tail-tracking technologies suffer from problems such as strong reliance on manual intervention and significant deviations that cannot be adaptively corrected, making it difficult to achieve accurate tracking of the tail of seamless steel pipes. Therefore, there is an urgent need for a precise tail-tracking method for hot-rolled seamless steel pipes that can integrate real-time signal determination and model prediction to achieve dynamic tracking of the tail position and improve tracking accuracy. Summary of the Invention

[0006] To address the technical problems of poor accuracy in tracking the tail end of seamless steel pipes and the inability to achieve online adjustment in existing technologies, and to reduce the frequent occurrence of steel pipe defects due to manual judgment and the heavy workload of operators, this invention provides a method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes. The technical solution is as follows:

[0007] A method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes, the method comprising: S1. Obtain continuous rolling mill equipment parameters, steel pipe continuous rolling process parameters, and signal transmission time; S2. Based on the steel pipe continuous rolling process parameters in S1, obtain the steel throwing signal of the first stand at the tail end, establish a tracking start time determination window, and determine the precise tracking start time at the tail end according to the rolling force change and motor speed change signals. S3. Based on the speed relationship between the steel pipe and the roll during the rolling process, the speed of the steel pipe entering the free section between the stands is given according to the roll linear speed. Taking the tracking start time judgment window in S2 as the judgment benchmark, combined with the center distance of the continuous rolling mill stands obtained in S1, the real-time position of the current support tube is calculated to form a prediction method for the tail position of the steel pipe. S4. Based on the predicted tail position of the steel pipe in S3, the predicted position result is evaluated by obtaining the steel throwing time of each stand in the continuous rolling mill, and the time deviation and spatial deviation are calculated to form the tail position tracking deviation index. S5. Based on the tracking deviation index of the tail position of the steel pipe in S4, when the accuracy requirements are met, the final predicted position of the previous rough pipe and the steel throwing time of each frame are used as the initial boundary conditions of the next rough pipe. Based on S3, the tail position of the next steel pipe is calculated and predicted in real time, and the tracking time of the next steel pipe is corrected according to the tracking deviation of the previous rough pipe. S6. Based on the deviation index of the tail position tracking of the steel pipe in S4, when the accuracy requirements are not met, the predicted time of each frame is compared with the actual steel throwing time, the problematic frame is located and the deviation is graded. Global correction or local parameter correction is performed on the identified problematic frame. After the adjustment is completed, return to S3 to continue to accurately track the tail of the lower branch steel pipe.

[0008] The parameters of the continuous rolling mill equipment in S1 include the first... Table rack and the first Table rack center distance , No. working diameter of bench rolls , No. Table frame drive system reduction ratio and the Rated speed of benchtop motor , The parameters of the continuous rolling process of steel pipes include the first Table stand steel throwing signal , No. Table stand pure rolling time , No. Table stand rolling force signal and the Tabletop rack motor speed signal , in, =1, 2, 3, 4, 5, 6; Signal transmission time includes the time it takes for the model to be sent to the HMI screen. and HMI transfer to Level 1 automation time .

[0009] The tracking start time determination window in S2 W i for: in, T s,i The time of steel ejection is obtained from the steel ejection signal; the judgment time domain is determined according to different steel pipe specifications during the rolling process, wherein... To determine the time domain in advance, For the time domain of lag determination; in, It is a periodically sampled signal. For the continuous steel throwing signal One cycle, k This is the trigger index of the steel throwing signal in the discrete sampling sequence.

[0010] In S2, the rolling force is monitored within the tracking start-up time determination window. With motor speed The trend of change is shown in the following formula: in, For rolling force The changing trend Motor speed The changing trend The signal sampling period corresponds to the sampling time of the rolling force signal and the motor speed signal.

[0011] A criterion for rolling force and motor speed is constructed by combining variables during regional stable rolling with a decision coefficient. When the first-order difference value of the rolling force signal shows a significant negative peak and the motor speed signal shows a significant positive peak, it is determined that the steel ejection stage may have begun. The formula is as follows: in, This is the determination coefficient for sudden changes in rolling force; The average maximum rolling force for stable regional rolling; This is the coefficient of rotational speed variation; The average maximum rotational speed for regional stable rolling.

[0012] The precise tail-end tracking start time in S2 is determined by combining three criteria: the tail-end first stand steel-throwing signal, the sudden change in rolling force, and the increase in motor speed. The formula is as follows: in, This is the function for determining the tail start time. , , These are the corresponding weighting coefficients, which are determined by the batch steel discarding signal. It is determined jointly based on the rolling force signal and the speed change. and ; The threshold for the start-up time determination function is determined based on the on-site rolling conditions; For the first Tracking time at the tail exit of the test rack; For precise tail-end tracking of the start-up moment; W i To determine the startup time; W 1 is the window for determining the start-up time of the first rack tracking.

[0013] The relationship between the speed of the roll and the steel pipe in S3 is as follows: when the steel pipe contacts the roll, there is a neutral point that makes the linear speed of the roll equal to the transmission speed of the steel pipe. In this invention, the speed change caused by the tension and temperature change in the free section is ignored. In engineering, the linear speed of the roll at this time is approximately equivalent to the speed of the steel pipe moving in the free section between the frames. The linear velocity of the rolls in S3 The calculation formula is as follows: The speed at which the steel pipe enters the free section between the frames The current branch pipe is tracked for real-time displacement. The calculation formula is: in, For the first The center distance from the first rack to the first rack; For the steel pipe in the first Table rack and the first Transmission speed of the free segment between machine racks; To track the start time after correcting for signal transmission delay; t This is the current calculation time; For the tail to reach the first Predicted timing for the rack; For the tail to reach the first Predicted arrival time of the rack; Using the signal window in S2 as the judgment area, when both the rolling force signal and the motor speed signal are in a steady state, the speed of the steel pipe moving in the free section between the stands is the speed at which the steel pipe enters the free section of the stand. If the rolling force signal or the motor speed signal exceeds the threshold, it will cause a disturbance to the speed. At this time, an additional speed disturbance correction coefficient is added to obtain the speed of the steel pipe moving in the free section between the stands, and the time when the steel pipe arrives at the stand and the position during the movement process are obtained, that is: steel pipe in the Table rack and the first Free section transmission speed between racks The calculation formula is: in, This is the velocity disturbance correction factor; This is the determination coefficient for sudden changes in rolling force; The average maximum rolling force for stable regional rolling; This is the coefficient of rotational speed variation; The average maximum rotational speed for regional stable rolling is given by the following parameters: speed disturbance correction coefficient, rolling force mutation judgment coefficient, and rotational speed variation coefficient are obtained by calibrating historical rolling data of steel pipes; the average maximum rolling force and the average maximum rotational speed for regional stable rolling are obtained by sliding statistics of rolling force and rotational speed signals. First, considering the delay time between the trigger signal transmission to the HMI screen and the delay time from the HMI screen to the first-level automation, the actual time when the steel pipe enters the free section between racks is obtained by subtracting the delay time from the rack start-up tracking time. This is the tracking start time after correcting for the signal transmission delay. ,in, For the first Tracking time at the tail exit of the platform rack. The time it takes for the model to be sent to the HMI screen. For HMI transfer to Level 1 automation time; The tail reaches the Table rack prediction time The calculation formula is: in, N This refers to the number of racks.

[0014] The formulas for calculating time deviation and spatial deviation in S4 are as follows: Where, Δ For the tail to reach the first Table rack time deviation; To actually obtain the first The steel throwing signal at the rear of the machine frame (i.e., the first) (Taiwan rack tail exit tracking time). For the tail to reach the first Predicted timing for the rack; Δ For the tail to reach the first Table rack space deviation; For the steel pipe in the first Table rack and the first Transmission speed of the free segment between machine racks; The tail position tracking deviation index The calculation formula is as follows: in, N Number of racks; For the first Table rack weighting coefficient, the weighting coefficient It is used to reflect the degree of influence of different stands on the tail position tracking accuracy, and can be set according to the degree of deformation of the stand during continuous rolling process combined with historical statistical deviations.

[0015] The tail-end overall deviation index in S4 is used for judgment. If the accuracy requirement is met, the tail-end tracking time and position results are considered accurate, and the tail-end tracking of the next branch steel pipe continues. The tail-end tracking start time is determined according to S2. The tracking time of the next branch steel pipe is corrected based on the measured transmission time and predicted transmission time of the previous accurately predicted steel pipe. In S5, the tracking time of the next branch steel pipe is corrected based on the measured transmission time and predicted transmission time of the previous accurately predicted steel pipe. The process is as follows: in, The tail evaluation criteria are used to determine whether the tail position tracking results are qualified, and to distinguish whether the prediction results can be used for subsequent correction calculations. For the first branch steel pipe in the first Table rack and the first Actual transmission time between racks For the (n-1)th steel pipe in the... Tracking time at the tail exit of the test rack; For the (n-1)th steel pipe in the... -1 rack tail exit tracking time; For the first branch steel pipe in the first Table rack and the first Predicted transmission time between racks; To track the start time after correcting for signal transmission delay; When rolling the (n-1)th steel pipe, the first -1 rack and the first i Center distance between machine racks; For the (n-1)th steel pipe in the... -1 rack and the first Transmission speed of the free segment between machine racks; For the defined first branch steel pipe in the first Table rack and the first Inter-rack transmission time correction factor; According to the tail deviation index in S4, when the upper support pipe meets the accuracy requirements, the tail tracking of the lower support pipe continues. The start time of the lower support pipe is determined according to S2. The movement speed of the free section of the pipe between the frames is calculated in combination with the correction coefficient of the upper support pipe. The specific tracking time of the lower support pipe is as follows: in, For the first The predicted first branch steel pipe after correction Table rack and the first Transmission time between racks; For the first branch steel pipe reaches the first Predicted timing for the rack; The starting time is tracked after correcting the signal transmission delay for the nth steel pipe. For the first branch steel pipe reaches the first -1 rack prediction time.

[0016] In S6, if the accuracy requirement is not met, the time deviation of each rack is first normalized according to the predicted transmission time between racks to construct a rack deviation sequence. Determine the direction of the deviation sequence of each rack. When the number of abnormal racks is greater than or equal to the number of racks that trigger global correction, the reason for the inaccurate prediction is determined to be a global deviation. Global correction is then performed on the predicted steel pipe of the next branch for this deviation. When the number of abnormal racks is less than the number of problematic racks that trigger global correction, it is determined to be a local rack abnormality. Only the predicted transmission time coefficient of the corresponding segment of the rack is locally updated, and an abnormality prompt is generated. The specific calculation process is as follows: in, To establish a pass / fail standard for the tail section; The ratio of normalized deviations of the frame; Δ For the first i The time deviation evaluation threshold for the mill stand is obtained by setting the on-site mill status and rolling force curve; Δ ( n ) represents the end of the nth steel pipe reaching the th Table rack time deviation; These are the parameters for deviation classification mapping; Based on the deviation classification mapping parameters, determine whether the error source is a global rack problem or a problem caused by a single rack, and perform source tracing and correction for different problems respectively; First, determine the number of abnormal racks. The calculation formula is as follows: in, It is a collection of abnormal racks; Then, based on the number of abnormal racks, if the global deviation condition is met, the global correction coefficient is calculated using the following formula: in, The number of problematic stands to trigger a global correction is set based on the rolling conditions and operating status of different batches. For the first Relative time error of the machine rack; This represents the mean relative time error of the abnormal rack. This is a global correction factor; The global correction gain coefficient is used to adjust the global time correction amplitude and is obtained through offline calibration using historical batch steel pipe tail tracking error data. For the first After the branch pipe is globally corrected, in the first Table rack and the first Transmission time between racks.

[0017] Otherwise, if the local deviation adjustment conditions are met, the actual average transport speed of the steel pipe in the free section between the frames is calculated based on the actual steel throwing time, and compared with the calculated speed. If the difference exceeds the signal deviation acceptance threshold, it is determined to be a speed modeling deviation, and the calculated speed value for that area is adjusted. The adjusted transmission speed of the steel pipe in the free section of the frame is obtained, and the process returns to S3 to continue tail tracking of the next steel pipe. The calculation formula is as follows: in, To correct the transmission speed of the free section between racks; For the first branch steel pipe Table rack and the first The actual average transmission speed between racks; The local stand speed adjustment coefficient is determined by a combination of mill speed and deviation.

[0018] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: The above solution addresses the technical problems of poor tracking accuracy and inability to adjust the tail of seamless steel pipes online, reducing the frequent occurrence of substandard steel pipes due to manual judgment and the heavy workload of operators. This method integrates real-time signal determination with model prediction, enabling dynamic tracking of the tail position and improving tracking accuracy. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0020] Figure 1 This is a flowchart of a method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes, provided by an embodiment of the present invention. Figure 2 This is a schematic diagram of steel ejection at each stand during the continuous rolling process of seamless steel pipe, obtained from an embodiment of the present invention. Figure 3 This is a schematic diagram of the rolling force signal and motor speed signal obtained in the continuous rolling process of seamless steel pipe according to an embodiment of the present invention, wherein (a) is a schematic diagram of the rolling force signal in the continuous rolling process of steel pipe, and (b) is a schematic diagram of the motor speed signal in the continuous rolling process of steel pipe; Figure 4 This is a schematic diagram of the tail tracking window as defined in an embodiment of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0022] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0023] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0024] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0025] This invention provides a method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes. For example... Figure 1 The flowchart shown is a method for precise tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes. This method may include the following steps:

[0026] S1. Obtain continuous rolling mill equipment parameters, steel pipe continuous rolling process parameters, and signal transmission time; S2. Based on the steel pipe continuous rolling process parameters in S1, obtain the steel throwing signal of the first stand at the tail end, establish a tracking start time determination window, and determine the precise tracking start time at the tail end according to the rolling force change and motor speed change signals. S3. Based on the speed relationship between the steel pipe and the roll during the rolling process, the speed of the steel pipe entering the free section between the stands is given according to the roll linear speed. Taking the tracking start time judgment window in S2 as the judgment benchmark, combined with the center distance of the continuous rolling mill stands obtained in S1, the real-time position of the current support tube is calculated to form a prediction method for the tail position of the steel pipe. S4. Based on the predicted tail position of the steel pipe in S3, the predicted position result is evaluated by obtaining the steel throwing time of each stand in the continuous rolling mill, and the time deviation and spatial deviation are calculated to form the tail position tracking deviation index. S5. Based on the tracking deviation index of the tail position of the steel pipe in S4, when the accuracy requirements are met, the final predicted position of the previous rough pipe and the steel throwing time of each frame are used as the initial boundary conditions of the next rough pipe. Based on S3, the tail position of the next steel pipe is calculated and predicted in real time, and the tracking time of the next steel pipe is corrected according to the tracking deviation of the previous rough pipe. S6. Based on the deviation index of the tail position tracking of the steel pipe in S4, when the accuracy requirements are not met, the predicted time of each frame is compared with the actual steel throwing time, the problematic frame is located and the deviation is graded. Global correction or local parameter correction is performed on the identified problematic frame. After the adjustment is completed, return to S3 to continue to accurately track the tail of the lower branch steel pipe.

[0027] The following examples illustrate this point.

[0028] S1: The center distances of each stand in the continuous rolling mill are shown in Table 1. Table 1 Center distance of each rack Table 2 shows the working diameter of the rolls, the rated speed of the motor, and the reduction ratio of the transmission system in the actual continuous rolling process of a certain batch of steel pipes in a certain factory. Since the parameters are different for different production batches, this table is only used as an example, and the subsequent example calculations will not be repeated.

[0029] Table 2 Parameters of Continuous Rolling Mill During the steel pipe rolling process, signals such as steel ejection signal, rolling force signal, and motor speed signal are received. Figure 2 , Figure 3 As shown.

[0030] S2: Based on the steel pipe continuous rolling process parameters in S1, the tail end first stand steel throwing signal is obtained to establish a tracking start time determination window. The precise tail end tracking start time is determined according to the rolling force change and motor speed signal. Figure 4 As shown in the figure, when the steel throwing signal is obtained, the rolling force shows a negative peak value and the motor speed shows a positive peak value; Establish a tail-end precise tracking time determination window, and determine the tail-end precise tracking time based on three criteria: S3: Based on the speed relationship between the steel pipe and the roll during the rolling process, the speed of the steel pipe entering the free section between the stands is given according to the linear speed of the roll. The signal window in S2 is used as the judgment benchmark. Combined with the distance between the stands of the continuous rolling mill obtained in S1, the time to reach each stand is calculated. The free section speed of each stand for different batches of steel pipe is calculated as shown in Table 3.

[0031] Table 3. Free section speeds of different steel pipe frames Based on the calculated speed of the free section between racks and the rack spacing, the predicted transmission time of the steel pipe in each rack is shown in Table 4.

[0032] Table 4. Predicted transmission time for each rack S4: Based on the steel pipe transmission time predicted in S3 and the tracking start time, the predicted arrival time is obtained; the predicted position result is evaluated by obtaining the steel throwing time of each stand in the continuous rolling mill, and the time deviation and spatial deviation are calculated to form the tail position tracking deviation index, as shown in Table 5.

[0033] Table 5 Tail Tracking Deviation Indicators The formula for calculating the overall tail deviation index is as follows: The example steel pipe is set to a tail-end evaluation standard of 0.5. According to the calculation results in the table, steel pipes No. 251B11133251112B240050 and No. 253B11329251113B040052 are evaluated as qualified steel pipes for tracking. According to S5: the next steel pipes No. 251B11133251112B240051 and No. 253B11329251113B040053 of the example qualified steel pipe are respectively corrected and predicted. The correction results are shown in Tables 6 and 7.

[0034] Table 6. Tracking Correction Based on Predicted Qualified Steel Pipe Supports (Table 1) Table 7. Tracking Correction Based on Predicted Qualified Steel Pipe Supports (Table 2) The example steel pipe sets the end evaluation pass standard to 0.5. According to the calculation results in the table, steel pipes No. 252B11560251119C130011 and No. 252B11560251119C130014 are judged as non-compliant steel pipes for tracking, as shown in Tables 8 and 9. According to S6, the number of deviation frames is first judged and then local or global adjustments are made. Table 8 Rack Anomaly Classification Judgment Table 1 Table 9 Rack Anomaly Classification Judgment Table 2 To trigger a global correction of the abnormal rack count, the example steel pipe is set to 4. According to Table 7, a global rack parameter correction is performed on the next steel pipe after 252B11560251119C130011, 252B11560251119C130012; a local rack parameter correction is performed on the next steel pipe after 252B11560251119C130014, 252B11560251119C130015. The correction results are shown in Tables 10 and 11. Table 10. Tail Tracking Status After Global Rack Parameter Correction Table 11 Tail Tracking Status After Local Frame Parameter Correction Based on the actual throwing time of the previous steel pipe and the spacing between the frames, the speed of the free section of each frame is calculated. As can be seen from Tables 10 and 11, after the abnormal frame classification and correction for unqualified steel pipes, the global deviation index of the next steel pipe has decreased significantly. After the unqualified judgment correction, it will return to S3 for accuracy judgment. If it is qualified, it will be corrected again, and finally the accurate tracking of the tail of the seamless steel pipe is achieved.

[0035] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipes, characterized in that, The method includes: S1. Obtain continuous rolling mill equipment parameters, steel pipe continuous rolling process parameters, and signal transmission time; S2. Based on the steel pipe continuous rolling process parameters in S1, obtain the steel throwing signal of the first stand at the tail end, establish a tracking start time determination window, and determine the precise tracking start time at the tail end according to the rolling force change and motor speed change signals. S3. Based on the speed relationship between the steel pipe and the roll during the rolling process, the speed of the steel pipe entering the free section between the stands is given according to the roll linear speed. Taking the tracking start time judgment window in S2 as the judgment benchmark, combined with the center distance of the continuous rolling mill stands obtained in S1, the real-time position of the current support tube is calculated to form a prediction method for the tail position of the steel pipe. S4. Based on the predicted tail position of the steel pipe in S3, the predicted position result is evaluated by obtaining the steel throwing time of each stand in the continuous rolling mill, and the time deviation and spatial deviation are calculated to form the tail position tracking deviation index. S5. Based on the tracking deviation index of the tail position of the steel pipe in S4, when the accuracy requirements are met, the final predicted position of the previous rough pipe and the steel throwing time of each frame are used as the initial boundary conditions of the next rough pipe. Based on S3, the tail position of the next steel pipe is calculated and predicted in real time, and the tracking time of the next steel pipe is corrected according to the tracking deviation of the previous rough pipe. S6. Based on the deviation index of the tail position tracking of the steel pipe in S4, when the accuracy requirements are not met, the predicted time of each frame is compared with the actual steel throwing time, the problematic frame is located and the deviation is graded. Global correction or local parameter correction is performed on the identified problematic frame. After the adjustment is completed, return to S3 to continue to accurately track the tail of the lower branch steel pipe.

2. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, The parameters of the continuous rolling mill equipment in S1 include the first... Table rack and the first Table rack center distance , No. working diameter of bench rolls , No. Table frame drive system reduction ratio and the Rated speed of benchtop motor , The parameters of the continuous rolling process of steel pipes include the first Table stand steel throwing signal , No. Table stand pure rolling time , No. Table stand rolling force signal and the Tabletop rack motor speed signal , in, =1, 2, 3, 4, 5, 6; Signal transmission time includes the time it takes for the model to be sent to the HMI screen. and HMI transfer to Level 1 automation time .

3. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, The tracking start time determination window in S2 W i for: in, T s,i The time of steel throwing is obtained from the steel throwing signal; To determine the time domain in advance, For the time domain of lag determination; in, It is a periodically sampled signal. For the continuous steel throwing signal One cycle, k This is the trigger index of the steel throwing signal in the discrete sampling sequence.

4. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, In S2, the rolling force is monitored within the tracking start-up time determination window. With motor speed The trend of change is shown in the following formula: in, For rolling force The changing trend Motor speed The changing trend The signal sampling period corresponds to the sampling time of the rolling force signal and the motor speed signal.

5. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, The precise tail-end tracking start time in S2 is determined by combining three criteria: the tail-end first stand steel throwing signal, the sudden change in rolling force, and the increase in motor speed. The formula is as follows: in, This is the function for determining the tail start time. , , These are the corresponding weight coefficients; The threshold for the startup time determination function; For the first Tracking time at the tail exit of the test rack; For precise tail-end tracking of the start-up moment; W i For the first Table rack tracking start-up time determination window; W 1 is the window for determining the start-up time of the first rack tracking.

6. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, The linear velocity of the rolls in S3 The calculation formula is as follows: The speed at which the steel pipe enters the free section between the frames The current branch pipe is tracked for real-time displacement. The calculation formula is: in, For the first Center distance from the first rack to the first rack; For the steel pipe in the first Table rack and the first Transmission speed of the free segment between machine racks; To track the start time after correcting for signal transmission delay; t This is the current calculation time; For the tail to reach the first Predicted timing for the rack; For the tail to reach the first Predicted arrival time of the rack; steel pipe in the Table rack and the first Free section transmission speed between racks The calculation formula is: in, This is the velocity disturbance correction factor; This is the determination coefficient for sudden changes in rolling force; The average maximum rolling force for stable regional rolling; This is the coefficient of rotational speed variation; The average maximum rotational speed for regional stable rolling; After correcting the signal transmission delay, the start time is tracked. ,in, For the first Tracking time at the tail exit of the machine frame. The time it takes for the model to be sent to the HMI screen. For HMI transfer to Level 1 automation time; The tail reaches the Table rack prediction time The calculation formula is: in, N This refers to the number of racks.

7. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, The formulas for calculating time deviation and spatial deviation in S4 are as follows: Where, Δ For the tail to reach the first Table rack time deviation; For the first Tracking time at the tail exit of the test rack; For the tail to reach the first Predicted timing for the rack; Δ For the tail to reach the first Table rack space deviation; For the steel pipe in the first Table rack and the first Transmission speed of the free segment between machine racks; The tail position tracking deviation index The calculation formula is as follows: in, N Number of racks; For the first Table rack weighting coefficient.

8. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, In step S5, the tracking time of the next steel pipe is corrected based on the measured transmission time of the previous accurately predicted steel pipe and the predicted transmission time. The process is as follows: in, To establish a pass / fail standard for the tail section; For the first branch steel pipe in the first Table rack and the first Actual transmission time between racks For the (n-1)th steel pipe in the nth... Tracking time at the tail exit of the test rack; For the (n-1)th steel pipe in the nth... -1 rack tail exit tracking time; For the first branch steel pipe in the first Table rack and the first Predicted transmission time between racks; To track the start time after correcting for signal transmission delay; When rolling the (n-1)th steel pipe Table rack and the first Center distance of the machine rack; For the (n-1)th steel pipe in the nth... -1 rack and the first Transmission speed of the free segment between machine racks; For the defined first branch steel pipe in the first Table rack and the first Inter-rack transmission time correction factor; The specific tracking time calculated for the lower branch steel pipe is as follows: in, For the first The predicted first branch steel pipe after correction Table rack and the first Transmission time between racks; For the first branch steel pipe reaches the first Predicted timing for the rack; The starting time is tracked after correcting the signal transmission delay for the nth steel pipe. For the first branch steel pipe reaches the first -1 rack prediction time.

9. The method for accurate tail-end tracking calculation in the hot continuous rolling process of seamless steel pipe according to claim 1, characterized in that, In S6, if the accuracy requirement is not met, the time deviation of each rack is first normalized according to the predicted transmission time between racks to construct a rack deviation sequence. Determine the direction of the deviation sequence of each rack. When the number of abnormal racks is greater than or equal to the number of racks that trigger global correction, the reason for the inaccurate prediction is determined to be a global deviation. Global correction is then performed on the predicted steel pipe of the next branch for this deviation. When the number of abnormal racks is less than the number of problematic racks that trigger global correction, it is determined to be a local rack abnormality. Only the predicted transmission time coefficient of the corresponding segment of the rack is locally updated, and an abnormality prompt is generated. The specific calculation process is as follows: in, To establish a pass / fail standard for the tail section; The ratio of normalized deviations of the frame; Δ For the first i The time deviation evaluation threshold for the rack; Δ ( n ) represents the end of the nth steel pipe reaching the th Table rack time deviation; These are the parameters for deviation classification mapping; Based on the deviation classification mapping parameters, determine whether the error source is a global rack problem or a problem caused by a single rack, and perform source tracing and correction for different problems respectively; First, determine the number of abnormal racks. The calculation formula is as follows: in, It is a collection of abnormal racks; Then, based on the number of abnormal racks, if the global deviation condition is met, the global correction coefficient is calculated using the following formula: in, To trigger a global correction of the number of problematic racks; For the first Relative time error of the machine rack; This represents the average relative time error of the abnormal racks. This is a global correction factor; This is a global correction gain coefficient; For the first After the branch pipe is globally corrected, in the first Table rack and the first Inter-rack transfer time; Otherwise, if the local deviation adjustment conditions are met, the actual average transport speed of the steel pipe in the free section between the frames is calculated based on the actual steel throwing time, and compared with the calculated speed. If the difference exceeds the signal deviation acceptance threshold, it is determined to be a speed modeling deviation, and the calculated speed value for that area is adjusted. The adjusted transmission speed of the steel pipe in the free section of the frame is obtained, and the process returns to S3 to continue tail tracking of the next steel pipe. The calculation formula is as follows: in, To correct the transmission speed of the free section between racks; For the first branch steel pipe Table rack and the first The actual average transmission speed between racks; This is the local rack speed adjustment coefficient.

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