Method for controlling tension, cpc runout and speed of annealing furnace in automatic state

Abstract

The application relates to the technical field of steel smelting system control, and particularly discloses a method for tension, CPC deviation and speed linkage control of an annealing furnace under an automatic state, an online tension control system of a continuous annealing furnace of a continuous annealing unit is established, the control system learns the production data in the early stage and online steel grades, and the optimal data learned is issued to a process control system L2; an automatic presetting model of the tension is established, the optimal internal stress distribution unit of the strip steel is calculated, the transverse distribution of the internal tension of the strip steel in the continuous annealing process is analyzed, the whole continuous annealing furnace is divided into N research units according to the logarithm of furnace rollers from the inlet to the outlet, and an arbitrary i unit is taken for research; a linkage control model of the tension, the CPC deviation and the speed of the annealing furnace is established and is used for automatic deviation correction of the control system; the application realizes accurate issuance of the tension, automatic adjustment of the production line speed and the tension of the annealing furnace according to the production situation, reduces the artificial burden, and the production efficiency is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of steel smelting system control technology, specifically to a method for automatic control of tension, CPC deviation, and speed linkage in an annealing furnace. Background Technology

[0002] In the continuous annealing process, hot warping, deviation and strip shape changes are key issues affecting product quality and production stability. At present, the tension control in the furnace of the continuous annealing production line mainly relies on the static secondary tension table preset by the operator. It cannot be dynamically adjusted according to the changes in working conditions, which leads to the following problems: (1) The tension setting is unreasonable when the specifications are transitioned, which can easily cause the weld to warp or the furnace to deviate; (2) The tension cannot be automatically adjusted when the working conditions change, which makes it difficult to correct the initial deviation and poses the risk of scraping and furnace opening; (3) When producing the limit specifications, defects such as warping and scratches are easy to occur; (4) Due to equipment limitations, the tension difference between adjacent sections is limited, which can easily cause a quick stop and restrict production efficiency.

[0003] Patent application number 202310750177.2 discloses an automatic tension control method and system for annealing furnaces. First, it collects and accumulates historical production-related data from the annealing furnace section to construct a basic dataset. Then, it filters effective data on stable steel coil production from the basic dataset to define the tension switching areas in each section of the furnace, using this as a high-quality production dataset. Finally, it uses a machine learning algorithm to establish an annealing furnace tension model, replacing the original manual tension preset values ​​with the model output. However, this invention only achieves precise distribution of a secondary tension level and does not take into account the actual production situation on the production line. When abnormal deviations occur, manual adjustment of tension and speed is still required. Untimely or incorrect manual adjustments still pose significant production risks.

[0004] The original technology involved technicians compiling a static tension table based on their production experience and sending it to the secondary level. The secondary level would then issue fixed tension values ​​based on the steel grade, strength, and specifications. However, with the continuous optimization of steel composition and production processes, the static table could no longer meet the needs of actual production. Operators needed to manually modify and set the tension values ​​based on their real-time experience. Furthermore, with changes in actual production conditions, personnel also needed to manually adjust the tension and production line speed over a long period of time, making it impossible to guarantee 100% fully automatic control.

[0005] Therefore, it is necessary to design a method for automatic control of annealing furnace tension, CPC deviation, and speed linkage to solve the production risks associated with manual adjustment of annealing furnace tension in existing technologies. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to provide a method for the coordinated control of tension, CPC deviation, and speed of an annealing furnace in an automatic state.

[0007] The technical solution adopted by this invention to solve its technical problem is: a method for automatic control of tension, CPC deviation, and speed linkage in an annealing furnace, comprising the following steps:

[0008] S1. Establish an online tension control system for the continuous annealing furnace of the continuous annealing unit. The control system learns the production data of the early stage and online steel grades, and sends the learned optimal data to the process control system L2.

[0009] S2. Establish an automatic tension preset model, calculate the optimal internal stress distribution unit of the strip, and analyze the lateral distribution of the internal tension of the strip during the continuous annealing process. Divide the entire continuous annealing furnace from the inlet to the outlet into N research units according to the number of furnace roll pairs, and take any i-th unit for research.

[0010] S3. Establish a linkage control model between annealing furnace tension and CPC deviation and speed. Design and train an annealing furnace strip tension adjustment model based on Q-Learning algorithm for automatic correction of the control system.

[0011] Specifically, in step S1, the control system reads production data from the PLC and stores the variables read from the PLC and the variables to be issued into the annealing furnace database.

[0012] Specifically, in step S2, the width of the strip is B. A coordinate system is established with the center of the furnace roll as the origin, with the working side as positive and the transmission side as negative. The coordinate value x of the centerline of each strip unit is... ij Represented as:

[0013] ;

[0014] During the modeling process, the tension difference of the strip steel along the longitudinal direction within each element is ignored, and the average tension σ is used. ij This represents the tension value of the strip in the i-th unit in the j-th element.

[0015] Specifically, during the continuous annealing process, the strip steel in any i-th unit exhibits a transverse temperature distribution T. ij Represented as:

[0016] ;

[0017] In the formula α ti0 α ti2 α ti4 Temperature coefficient;

[0018] Using the middle stripe (i.e., the m+1 stripe) as the reference within the i-th cell, the temperature difference ΔT between any j-th stripe and the middle stripe is... ij Represented as:

[0019] ;

[0020] Thus, the deformation difference ΔlT between the j-th element and the middle element within the i-th element due to the temperature difference... ij Represented as:

[0021] ;

[0022] In the formula: β is the coefficient of linear expansion of the strip steel, unit: / ℃;

[0023] H i The distance between the center lines of the upper and lower furnace rollers within the i-th unit, in mm;

[0024] R i The radius of the furnace roller in the i-th unit is in mm.

[0025] Specifically, the continuous annealing process causes localized plastic deformation of the strip steel in the process section of the continuous annealing unit, thus its shape also changes accordingly. For any i-th unit, the incoming strip shape refers to the exit strip shape of the (i-1)-th unit. The incoming strip shape is represented by a hexagonal curve as follows:

[0026] ;

[0027] In the formula: α ij The incoming material plate shape is I for the i-th unit;

[0028] α kbi Let be the material shape coefficient of the i-th unit;

[0029] According to the definition of plate shape, the deformation difference Δl between the j-th stripe and the middle stripe in the i-th unit due to the difference in the shape of the incoming plate is known. bij Represented as

[0030] ;

[0031] In the continuous annealing process, the furnace roll of the i-th unit includes two rolls: an upper furnace roll and a lower furnace roll. Its actual roll shape consists of three parts: the original roll shape, the amount of wear, and the thermal crown of the roll, which is represented as follows:

[0032] ;

[0033] In the formula D ssij The actual roll type distribution of the furnace rolls in the i-th unit, in mm;

[0034] D xsij The actual roll type distribution of the lower furnace rolls in the i-th unit, in mm;

[0035] D syijThe original roll shape distribution of the furnace rolls in the i-th unit, in mm;

[0036] D xyij The original roll shape distribution of the lower furnace roll in the i-th unit, in mm;

[0037] ΔD stij The hot roll type distribution of the furnace rollers in the i-th unit, unit: mm;

[0038] ΔD xtij The distribution of the hot roll type of the lower furnace roll in the i-th unit, in mm;

[0039] ΔD smij The wear distribution of the furnace rollers in the i-th unit is given in mm.

[0040] ΔD xmij The wear distribution of the lower furnace roller in the i-th unit is given in mm.

[0041] The deformation difference Δl between the j-th stripe and the middle stripe within the i-th unit due to the shape of the furnace roll. Dij Represented as:

[0042] ;

[0043] When furnace rollers have vertical or horizontal errors due to processing or installation, it causes strip deformation differences during the strip annealing process, specifically expressed as:

[0044] ;

[0045] In the formula δ csi Let be the maximum error value of the working side on the i-th unit in the vertical direction, defined as positive upwards, in mm;

[0046] δc xi The maximum error value in the vertical direction of the working side of the lower furnace roller of the i-th unit is defined as negative when downward, and the unit is mm;

[0047] δ ssi Let be the maximum error value in the horizontal direction of the working side of the upper furnace roller in the i-th unit, and define the unit's running direction as positive. Unit: mm;

[0048] δ sxi The maximum error value in the horizontal direction of the working side of the lower furnace roller of the i-th unit is defined as negative in the opposite direction of unit operation, in mm;

[0049] Δl sij The difference in strip deformation caused by the horizontal and vertical errors of the furnace rollers in the i-th unit, in mm;

[0050] Δl scijThe difference in strip deformation caused by the vertical error of the furnace roller in the i-th unit, in mm;

[0051] Δl ssij The difference in strip deformation caused by the horizontal error of the furnace roller in the i-th unit is expressed in mm.

[0052] Specifically, during the continuous annealing process, the deformation difference between the strip elements within the i-th unit has the deformation compatibility relationship shown in the following equation:

[0053] ;

[0054] The results were: ;

[0055] Under the condition that the strip does not undergo plastic deformation within the strip, the deformation relationship between the internal tension of the strip and the temperature difference, the incoming strip shape, the furnace roll profile, and the horizontal and vertical errors of the furnace rolls satisfies the following equation:

[0056] ;

[0057] When the strip steel undergoes plastic deformation within the strip, the above formula no longer holds true. At this time, the internal tension of the strip steel is expressed by the following formula:

[0058] ;

[0059] In the formula σ sTij For strip steel at temperature T ij Yield strength at a given time, unit: MPa; E and δ are regression coefficients, determined by the steel grade;

[0060] There are a total of 2m+1 equations, and the internal stress of the strip element has σ. i1 ,σ i2 ,…,σ i(2m+1) There are a total of 2m+1, plus the deformation of the j-th element caused by tension. There are a total of 2m+2 unknowns, therefore, we need to add a force balance equation, namely:

[0061] ;

[0062] In the formula σ i The average tension of the strip in the i-th unit is expressed in MPa.

[0063] The present invention has the following beneficial effects:

[0064] This invention presents a method for automatically controlling the tension, CPC deviation, and speed of an annealing furnace. This method enables precise tension application and automatic adjustment of production line speed and annealing furnace tension based on production conditions, reducing manual workload. The automatic linkage adjustment and feedback control of annealing furnace tension and CPC deviation ensures stable operation of the strip steel within the annealing furnace, significantly improving production efficiency. Attached Figure Description

[0065] Figure 1 This is a block diagram of the data management function of the present invention.

[0066] Figure 2 This is a schematic diagram showing the annealing furnace rollers of the present invention divided into N research units.

[0067] Figure 3 This is a schematic diagram of the strip steel of the present invention being divided into 2m+1 strips along the width direction.

[0068] Figure 4 This is a schematic diagram illustrating the horizontal error of the furnace rollers in the annealing furnace of the present invention.

[0069] Figure 5 This is a schematic diagram of the vertical error of the furnace rollers in the annealing furnace of the present invention.

[0070] Figure 6 This is a system architecture diagram for the automatic correction system of this invention.

[0071] Figure 7 This is a logic diagram of the linkage control of tension, CPC deviation, and speed in the annealing furnace of the present invention. Detailed Implementation

[0072] The technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0073] A method for automatic tension, CPC deviation, and speed linkage control of an annealing furnace involves: first, collecting tension data for all product specifications on the production line; establishing a multi-task learning AI model with a multi-gate hybrid expert network structure and inputting parameters into the AI ​​model; training the AI ​​model systematically; when the weld seam at the strip head reaches various positions within the annealing furnace, using the AI ​​model to control process parameters and issuing a tension control system for execution; online analysis of the CPC cylinder position to determine if the strip is deviating and automatically adjusting the tension; online analysis of the CPC cylinder position to determine if the strip needs speed adjustment; these steps continue until the production of the coil of strip is completed. This invention achieves automatic linkage adjustment and feedback control of annealing furnace tension and CPC deviation, enabling stable operation of the strip within the annealing furnace and significantly improving production efficiency. Specifically, it includes the following steps:

[0074] I. Establish an online tension control system for the continuous annealing furnace in the continuous annealing unit.

[0075] 1. For example Figure 1 As shown, the control system includes a primary basic automation system, a secondary process control system, and a tertiary manufacturing execution system. It learns production data from the early stages and online steel grades, and then sends the learned optimal data to the process control system L2.

[0076] 2. Read various production data from the PLC, including production technology data and steel coil defect data. This system will store the variables read from the PLC and the variables to be issued into a dedicated database for the annealing furnace, which will facilitate real-time access and subsequent verification.

[0077] 2. Establish an automatic tension preset model and calculate the optimal internal stress distribution unit for the strip.

[0078] like Figures 2-3 As shown, the transverse distribution of internal tension in the strip during continuous annealing is first analyzed. The entire continuous annealing furnace, from the inlet to the outlet, is divided into N research units according to the number of furnace roll pairs, and any i-th unit is selected for study; for example... Figure 3 As shown, each strip of steel starts from the upper generatrix of the furnace rolls. Figure 3 Point A in the diagram), and the lower generatrix of the lower furnace roller as the endpoint ( Figure 3 Point D in the middle). Thus, for each transverse strip unit, its longitudinal part consists of the portion where the strip contacts the upper furnace roll ( Figure 3 Section AB), the section between the furnace rollers ( Figure 3 (Central BC section) and the contact section between the strip and the lower furnace roll ( Figure 3 The strip consists of three parts (sections C, D, and E). Assuming the strip width is B, and a coordinate system is established with the center of the furnace roll as the origin, with the working side as positive and the drive side as negative, then the coordinate value x of the centerline of each strip unit is... ij It can be represented as:

[0079] .

[0080] During the modeling process, the tension difference of the strip steel along the longitudinal direction within each element is ignored, and the average tension σ is used. ij This represents the tension value of the strip in the i-th unit in the j-th element.

[0081] During continuous annealing of strip steel, the temperature distribution T along the transverse direction of the strip steel in any i-th unit is... ij Represented as:

[0082] ;

[0083] In the formula α ti0 α ti2 α ti4 This is the temperature coefficient.

[0084] Using the middle stripe (i.e., the m+1 stripe) as the reference within the i-th cell, the temperature difference ΔT between any j-th stripe and the middle stripe is... ij Represented as:

[0085] .

[0086] Thus, the deformation difference ΔlT between the j-th element and the middle element within the i-th element due to the temperature difference... ij Represented as:

[0087] ;

[0088] In the formula: β is the coefficient of linear expansion of the strip steel, unit: / ℃;

[0089] H i The distance between the center lines of the upper and lower furnace rollers within the i-th unit, in mm;

[0090] R i The radius of the furnace roller in the i-th unit is in mm.

[0091] In continuous annealing, the strip may undergo localized plastic deformation in the high-temperature and high-tension sections of the strip, thus changing its shape. For any i-th unit, the incoming strip shape refers to the exit strip shape of the (i-1)-th unit. Considering the issues of higher-order waviness and asymmetric waviness, the incoming strip shape is represented by a sixth-order curve as follows:

[0092] ;

[0093] In the formula: α ij The incoming material plate shape is I for the i-th unit;

[0094] αkbi Let be the material shape coefficient of the i-th unit.

[0095] According to the definition of plate shape, the deformation difference Δl between the j-th stripe and the middle stripe in the i-th unit due to the difference in the shape of the incoming plate is known. bij Represented as

[0096] .

[0097] In the continuous annealing process, the furnace roll of the i-th unit includes two rolls: an upper furnace roll and a lower furnace roll. Its actual roll shape consists of three parts: the original roll shape, the amount of wear, and the thermal crown of the roll, which is represented as follows:

[0098] ;

[0099] In the formula D ssij The actual roll type distribution of the furnace rolls in the i-th unit, in mm;

[0100] D xsij The actual roll type distribution of the lower furnace rolls in the i-th unit, in mm;

[0101] D syij The original roll shape distribution of the furnace rolls in the i-th unit, in mm;

[0102] D xyij The original roll shape distribution of the lower furnace roll in the i-th unit, in mm;

[0103] ΔD stij The hot roll type distribution of the furnace rollers in the i-th unit, unit: mm;

[0104] ΔD xtij The distribution of the hot roll type of the lower furnace roll in the i-th unit, in mm;

[0105] ΔD smij The wear distribution of the furnace rollers in the i-th unit is given in mm.

[0106] ΔD xmij The wear distribution of the lower furnace roller in the i-th unit is given in mm.

[0107] like Figure 3 As shown, the deformation difference Δl between the j-th stripe and the middle stripe within the i-th unit due to the shape of the furnace roll is... Dij Represented as:

[0108] .

[0109] like Figures 4-5 As shown, when the furnace rolls have vertical or horizontal errors due to processing or installation reasons, it causes strip deformation differences during the strip annealing process, specifically expressed as follows:

[0110] ;

[0111] In the formula δ csi Let be the maximum error value of the working side on the i-th unit in the vertical direction, defined as positive upwards, in mm;

[0112] δc xi The maximum error value in the vertical direction of the working side of the lower furnace roller of the i-th unit is defined as negative when downward, and the unit is mm;

[0113] δ ssi Let be the maximum error value in the horizontal direction of the working side of the upper furnace roller in the i-th unit, and define the unit's running direction as positive. Unit: mm;

[0114] δ sxi The maximum error value in the horizontal direction of the working side of the lower furnace roller of the i-th unit is defined as negative in the opposite direction of unit operation, in mm;

[0115] Δl sij The difference in strip deformation caused by the horizontal and vertical errors of the furnace rollers in the i-th unit, in mm;

[0116] Δl scij The difference in strip deformation caused by the vertical error of the furnace roller in the i-th unit, in mm;

[0117] Δl ssij The difference in strip deformation caused by the horizontal error of the furnace roller in the i-th unit is expressed in mm.

[0118] Analysis reveals that during continuous annealing, the deformation difference between strip elements within the i-th element exhibits the deformation compatibility relationship shown in the equation:

[0119] ;

[0120] The results were: .

[0121] Under the condition that the strip does not undergo plastic deformation within the strip, the deformation relationship between the internal tension of the strip and the temperature difference, the incoming strip shape, the furnace roll profile, and the horizontal and vertical errors of the furnace rolls satisfies the following equation:

[0122] .

[0123] When the strip steel undergoes plastic deformation within the strip, the above formula no longer holds true. At this time, the internal tension of the strip steel is expressed by the following formula:

[0124] ;

[0125] In the formula σ sTijFor strip steel at temperature T ij The yield strength at a given time is expressed in MPa; E and δ are regression coefficients, determined by the steel grade.

[0126] There are a total of 2m+1 equations, and the internal stress of the strip element has σ. i1 ,σ i2 ,…,σ i(2m+1) There are a total of 2m+1, plus the deformation of the j-th element caused by tension. There are a total of 2m+2 unknowns, therefore, we need to add a force balance equation, namely:

[0127] ;

[0128] In the formula σ i The average tension of the strip in the i-th unit, in MPa, is given by the process.

[0129] Thus, solving the above equations simultaneously results in 2m+2 equations, with σ being the unknown. i1 ,σ i2 ,…,σ i(2m+1) , There are a total of 2m+2 elements, so a certain algorithm can be used to accurately solve the stress distribution inside the strip. The basic idea is as follows: First, assume that no plastic deformation occurs in any element, solve the linear equation system to obtain the tension distribution value of all elements, then compare the tension of each element with the yield strength, find the elements whose tension exceeds the yield strength, and for the elements whose tension does not exceed the yield strength, still use the elastic deformation equation, solve the equations simultaneously to obtain the tensile stress distribution inside the strip, and continue to compare until the tension of the elements corresponding to all the equations is less than the yield strength of the strip.

[0130] III. Establishing a linkage control model between annealing furnace tension, CPC deviation, and speed.

[0131] 1. Design and training of a strip tension adjustment model for annealing furnace based on Q-Learning algorithm to realize the automatic correction function of the system.

[0132] Q-Learning is a classic reinforcement learning algorithm. Its key feature is that it stores and updates all Q-values ​​during training in a table, where each Q-value represents the action-value function Q(s,α). When selecting an action, it chooses the action with the largest Q-value corresponding to the current state from this table. The Q-value update formula uses the temporal difference method, as shown below:

[0133] ;

[0134] in, This represents the learning rate, which controls the rate at which the Q-value increases relative to the previous Q-value with each update. This represents the discount factor, which controls how much importance the agent places on past experiences; Representing the benefits in memory, and correspondingly It refers to immediate benefits.

[0135] The Q-Learning algorithm, due to its Q-table design, has requirements regarding the size of the state space. It can simply and effectively solve problems where state changes are within a finite and small range. However, for problems where the state space size is unknown and state changes are uncontrollable, the Q-Learning algorithm requires careful consideration of the Q-table design. The Q-table must not grow indefinitely; otherwise, its excessive size over time will risk causing it to crash. The Q-Learning algorithm flow is as follows:

[0136] 1. Initialization The matrix determines α and γ.

[0137] 2. Repeat, given an initial state s; Repeat for each sample in each sequence.

[0138] (1) Selecting behavior based on behavior selection mechanism Receive instant rewards and the next state ;

[0139] (2) Update the Q value: ;

[0140] (3) ; This is the final state.

[0141] 3. Output the final strategy .

[0142] like Figure 6 As shown, after the system detects that the strip is deviating, the system will issue the tension adjustment value calculated by the model, thereby achieving the function of automatic deviation correction.

[0143] like Figure 7 As shown, the automatic speed reduction control logic of the strip misalignment system is as follows: When the strip width is ≤1500mm and the misalignment is ≥100, the speed is automatically reduced by 50 every 2-3 seconds until the speed is less than 120mm / s, or the misalignment is <100; when the strip width is ≤1500mm and the misalignment is <100, the process is skipped. When the strip width is >1500mm and the misalignment is ≥80, the speed is automatically reduced by 40 every 2-3 seconds until the misalignment is <80; when the strip width is >1500mm and the misalignment is <80, the process is skipped.

[0144] The control logic for automatic speed reduction when the vehicle veers off course is as follows: During normal speed reduction, the tension in the veerging section is increased by 10%. If the veergence increases further, the tension is increased by another 10%. Once the veergence returns to normal, the original tension value is restored. For abnormally large speed reductions (≤150mm / s), if there is a manual adjustment, the tension is restored to the secondary target value. If the manual adjustment is negative, the tension is reduced by 10% for every 20% decrease in speed, until the lower limit is reached. If there is no manual adjustment, the tension is reduced by 10% of the secondary target value.

[0145] This invention is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0146] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A method for automatic control of tension, CPC deviation, and speed linkage in an annealing furnace, characterized in that, Includes the following steps: S1. Establish an online tension control system for the continuous annealing furnace of the continuous annealing unit. The control system learns the production data of the early stage and online steel grades, and sends the learned optimal data to the process control system L2. S2. Establish an automatic tension preset model, calculate the optimal internal stress distribution unit of the strip, and analyze the lateral distribution of the internal tension of the strip during the continuous annealing process. Divide the entire continuous annealing furnace from the inlet to the outlet into N research units according to the number of furnace roll pairs, and take any i-th unit for research. S3. Establish a linkage control model between annealing furnace tension and CPC deviation and speed. Design and train an annealing furnace strip tension adjustment model based on Q-Learning algorithm for automatic correction of the control system.

2. The method for automatic tension, CPC deviation, and speed linkage control of an annealing furnace according to claim 1, characterized in that, In step S1, the control system reads production data from the PLC and stores the variables read from the PLC and the variables to be issued into the annealing furnace database.

3. The method for automatic tension, CPC deviation, and speed linkage control of an annealing furnace according to claim 1, characterized in that, In step S2, the width of the strip is B. A coordinate system is established with the center of the furnace roll as the origin, with the working side as positive and the transmission side as negative. The coordinate value x of the centerline of each strip unit is... ij Represented as: ； During the modeling process, the tension difference of the strip steel along the longitudinal direction within each element is ignored, and the average tension σ is used. ij This represents the tension value of the strip in the i-th unit in the j-th element.

4. The method for automatic tension, CPC deviation, and speed linkage control of an annealing furnace according to claim 3, characterized in that, During the continuous annealing process, the strip steel in any i-th unit follows the transverse temperature distribution T. ij Represented as: ； In the formula α ti0 α ti2 α ti4 Temperature coefficient; Using the middle stripe (i.e., the m+1 stripe) as the reference within the i-th cell, the temperature difference ΔT between any j-th stripe and the middle stripe is... ij Represented as: ； Thus, the deformation difference ΔlT between the j-th element and the middle element within the i-th element due to the temperature difference... ij Represented as: ； In the formula: β is the coefficient of linear expansion of the strip steel, unit: / ℃; H i The distance between the center lines of the upper and lower furnace rollers within the i-th unit, in mm; R i The radius of the furnace roller in the i-th unit is in mm.

5. The method for automatic tension, CPC deviation, and speed linkage control of an annealing furnace according to claim 4, characterized in that, The continuous annealing process causes localized plastic deformation of the strip in the process section of the continuous annealing unit, thus its shape also changes accordingly. For any i-th unit, the incoming strip shape refers to the exit strip shape of the (i-1)-th unit. The incoming strip shape is represented by a hexagonal curve as follows: ； In the formula: α ij The incoming material plate shape is I for the i-th unit; α kbi Let be the material shape coefficient of the i-th unit; According to the definition of plate shape, the deformation difference Δl between the j-th stripe and the middle stripe in the i-th unit due to the difference in the shape of the incoming plate is known. bij Represented as ； In the continuous annealing process, the furnace roll of the i-th unit includes two rolls: an upper furnace roll and a lower furnace roll. Its actual roll shape consists of three parts: the original roll shape, the amount of wear, and the thermal crown of the roll, which is represented as follows: ； In the formula D ssij The actual roll type distribution of the furnace rolls in the i-th unit, in mm; D xsij The actual roll type distribution of the lower furnace rolls in the i-th unit, in mm; D syij The original roll shape distribution of the furnace rolls in the i-th unit, in mm; D xyij The original roll shape distribution of the lower furnace roll in the i-th unit, in mm; ΔD stij The hot roll type distribution of the furnace rollers in the i-th unit, unit: mm; ΔD xtij The distribution of the hot roll type of the lower furnace roll in the i-th unit, in mm; ΔD smij The wear distribution of the furnace rollers in the i-th unit is given in mm. ΔD xmij The wear distribution of the lower furnace roller in the i-th unit is given in mm. The deformation difference Δl between the j-th stripe and the middle stripe within the i-th unit due to the shape of the furnace roll. Dij Represented as: ； When furnace rollers have vertical or horizontal errors due to processing or installation, it causes strip deformation differences during the strip annealing process, specifically expressed as: ； In the formula δ csi Let be the maximum error value of the working side on the i-th unit in the vertical direction, defined as positive upwards, in mm; δc xi The maximum error value in the vertical direction of the working side of the lower furnace roller of the i-th unit is defined as negative when downward, and the unit is mm; δ ssi Let be the maximum error value in the horizontal direction of the working side of the upper furnace roller in the i-th unit, and define the unit's running direction as positive. Unit: mm; δ sxi The maximum error value in the horizontal direction of the working side of the lower furnace roller of the i-th unit is defined as negative in the opposite direction of unit operation, in mm; Δl sij The difference in strip deformation caused by the horizontal and vertical errors of the furnace rollers in the i-th unit, in mm; Δl scij The difference in strip deformation caused by the vertical error of the furnace roller in the i-th unit, in mm; Δl ssij The difference in strip deformation caused by the horizontal error of the furnace roller in the i-th unit is expressed in mm.

6. The method for automatic tension, CPC deviation, and speed linkage control of an annealing furnace according to claim 5, characterized in that, During the continuous annealing process, the deformation difference of the strip elements within the i-th unit has the deformation compatibility relationship shown in the equation: ； The results were: ; Under the condition that the strip does not undergo plastic deformation within the strip, the deformation relationship between the internal tension of the strip and the temperature difference, the incoming strip shape, the furnace roll profile, and the horizontal and vertical errors of the furnace rolls satisfies the following equation: ； When the strip steel undergoes plastic deformation within the strip, the above formula no longer holds true. At this time, the internal tension of the strip steel is expressed by the following formula: ； In the formula σ sTij For strip steel at temperature T ij Yield strength at a given time, unit: MPa; E and δ are regression coefficients, determined by the steel grade; There are a total of 2m+1 equations, and the internal stress of the strip element has σ. i1 ,σ i2 ,…,σ i(2m+1) There are a total of 2m+1, plus the deformation of the j-th element caused by tension. There are a total of 2m+2 unknowns, therefore, we need to add a force balance equation, namely: ； In the formula σ i The average tension of the strip in the i-th unit is expressed in MPa.

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