A control method and device for controlling the change rate of an AGC control quantity in endless casting and rolling

Abstract

This invention discloses a method and device for controlling the rate of change of AGC control quantities in headless continuous casting and rolling, belonging to the field of metallurgical steel rolling automation control technology. The method includes the following steps: S1, calibrating a robust reference limit; S2, based on the robust reference limit obtained in step S1, performing dimensionless deviation correction and stiffness matching correction on the actual working conditions, and then calculating the actual working condition reference limit; S3, using fuzzy control theory to reduce the actual working condition reference limit obtained in step S2 to obtain a risk-adjusted limit; S4, comparing the risk-adjusted limit obtained in step S3 with the maximum allowable roll gap adjustment speed hard limit of the rolling mill equipment, and selecting the smaller value as the final roll gap adjustment speed limit. This invention achieves accurate, stable, and adaptive adjustment of the roll gap adjustment speed limit through calibrating a robust reference limit, adaptive correction, fuzzy control, and hard limit fallback.

Description

Technical Field

[0001] This invention belongs to the field of automated control technology for metallurgical steel rolling, specifically relating to a method and device for controlling the rate of change of AGC control quantities in headless continuous casting and rolling. Background Technology

[0002] In the continuous casting and rolling process, the output value of the automatic thickness control (AGC) system, as the core command for roll gap compensation, directly determines the control accuracy and dynamic response quality of the strip thickness. The rate of change of this output value is particularly critical: too fast a rate can easily induce sudden tension changes and drastic fluctuations in rolling force, leading to serious accidents such as strip breakage and steel piling; too slow a rate limits the system's responsiveness, making it difficult to meet the dual requirements of rapid and stable thickness adjustment under conditions such as varying specifications and fluctuating incoming materials. Therefore, how to reasonably constrain the rate of change of the AGC control quantity while ensuring the system's dynamic performance becomes crucial to ensuring the safe and efficient operation of the thickness control system.

[0003] Currently, the setting of limits for the rate of change of AGC control variables is still mainly based on empirical calibration, lacking systematic theoretical modeling support, making it difficult to adapt to the characteristics of continuous variable specifications and fast-paced production in endless continuous casting and rolling. At the same time, existing methods generally use single-parameter thresholds for control, neglecting the risk superposition effect under multi-parameter coordinated operating conditions, resulting in insufficient safety redundancy and poor adaptability to operating conditions. Therefore, there is an urgent need to develop a control method for the rate of change of AGC control variables to achieve precise dynamic constraints on the rate of change, thereby ensuring system stability while meeting the high-precision and high-efficiency control requirements under complex operating conditions, possessing significant theoretical innovation and engineering application value. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method and device for controlling the rate of change of AGC control quantity in headless continuous casting and rolling, so as to achieve accurate, stable and adaptive adjustment of the roll gap adjustment speed limit.

[0005] The objective of this invention is achieved through the following technical solution: This invention provides a method for controlling the rate of change of AGC control quantities in headless continuous casting and rolling, comprising the following steps: S1, calibrating robust reference limits; S2, based on the robust reference limit mentioned in step S1, and performing dimensionless deviation correction and stiffness matching correction on the actual working conditions, the reference limit for the actual working conditions is calculated. S3, using fuzzy control theory, the actual working condition baseline limit obtained in step S2 is reduced to obtain the risk control post-limit; S4. Compare the risk control limit obtained in step S3 with the maximum allowable roll gap adjustment speed hard limit of the rolling mill equipment, and select the smaller value of the two as the final roll gap adjustment speed limit.

[0006] In some embodiments, in step S1, the method for calibrating the robust reference limit is as follows: First, a typical specification with strip material, frame stiffness, and specifications that are all design nominal values ​​and have no uncertainty interference is selected as a reference pass. Then, based on the core parameters of the reference pass, the maximum tension under the reference pass is calculated based on the tension stress theory model. The maximum safe compensation amount of AGC is obtained by limiting the amplitude of AGC compensation based on the frame stiffness constraint. Finally, the robust reference limit of the reference pass is obtained by introducing the safety margin coefficient.

[0007] Furthermore, the core parameter of the reference pass is the reference strip width. Reference strip thickness Reference mill exit speed Reference rack exit speed .

[0008] Furthermore, the formula for calculating the maximum tension under the reference pass is as follows:

[0009] in: The maximum tension is referenced for the specified track number. Allowable tensile stress, inherent property value of rolled material; For reference strip thickness ; For reference strip width ; The formula for calculating the maximum safety compensation amount of AGC is as follows: For the rigidity of the rolling mill stand; The robust baseline limit for the reference track is calculated using the following formula: η is the cold start safety margin coefficient, with a value of 0.7 to 0.9.

[0010] In some embodiments, in step S2, The dimensionless deviation correction formula is as follows: , in, For the actual strip thickness, For the actual mill exit speed, For actual rack exit speed, For reference strip thickness, For reference mill exit speed, For reference rack exit speed; The stiffness matching correction formula is as follows:

[0011] in, This is the material modulus of the strip steel under actual working conditions. For the rigidity of the rolling mill stand; The formula for calculating the actual operating condition reference limit is as follows:

[0012] .

[0013] In some embodiments, in step S3, the fuzzy control theory is specifically implemented as follows: First, the relative deviation between the actual process parameters and the danger threshold is determined as the input term of the fuzzy control, and the limit reduction coefficient in the 0~1 interval is the output term of the fuzzy control; second, the input term is divided into four fuzzy levels: no risk, low risk, medium risk, and high risk, and a fuzzy rule base is established based on the hot rolling process; third, the reduction coefficient is output in different directions, with the direction of increasing roll gap corresponding to the first reduction coefficient. K 1. The direction of decreasing roll gap corresponds to the second reduction coefficient. Finally, output the risk control limit value and the limit value in the direction of increasing roll gap. Limit of roll gap reduction direction ,in, .

[0014] Furthermore, the input items for the fuzzy control are tension deviation rate, rolling force over-limit rate, and motor current over-limit rate.

[0015] Furthermore, the first reduction coefficient K 1 represents the minimum value among the three sets of deviation rates—the deviation between the actual and set values ​​of the inlet tension, the deviation between the actual and set values ​​of the outlet tension, and the deviation between the actual and minimum rolling force—obtained through fuzzy rules.

[0016] Furthermore, the second reduction factor K 2 represents the minimum value among the four sets of deviation rates—the deviation between the actual and set values ​​of the inlet tension, the deviation between the actual and set values ​​of the outlet tension, the deviation between the actual and maximum rolling force, and the deviation between the actual and maximum values ​​of the main motor current—obtained through fuzzy rules.

[0017] The present invention also provides a control device for the rate of change of AGC control quantity in endless continuous casting and rolling, comprising: a memory and a processor, wherein the memory stores at least one program, and the at least one program is executed by the processor to implement the method described above.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention, based on a calibrated robust baseline limit, performs dimensionless deviation correction and stiffness matching correction on actual working conditions to derive a baseline limit for the actual working conditions. Then, using fuzzy control theory, it reduces this baseline limit to obtain a risk-adjusted limit. This risk-adjusted limit is compared with the hard limit of the maximum allowable roll gap adjustment speed for the rolling mill, and the smaller of the two is selected as the final roll gap adjustment speed limit. This solution effectively solves the shortcomings of existing AGC control variable change rate limit setting technologies, which rely on empirical calibration (lacking theoretical support), lack adaptability to changing specifications, and have a single risk control dimension and poor adaptability. This control method provides a reliable rate constraint for the stable operation of the AGC system, possessing significant engineering application value and economic benefits. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the method for controlling the rate of change of AGC control quantity in the headless continuous casting and rolling process of the present invention. Figure 2 A schematic diagram of the control device for the rate of change of AGC control quantity in headless continuous casting and rolling according to Embodiment 2 of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0021] This invention provides a robust adaptive limit control method for the rate of change of AGC control quantity in endless continuous casting and rolling, comprising the following steps ( Figure 1 ): S1, based on the tension stress theory model, calculates the reference rate of compression under the reference pass and calibrates the robust reference limit; Typical specifications from the rolling process are selected as reference passes (nominal operating conditions; typical specifications can be Q235 strip material, 7000 kN / mm stand stiffness, strip width 1200 mm, thickness 2.0 mm, mill exit speed 15.0 m / s, and stand exit speed 15.0 m / s). Under this condition, the strip material, stand stiffness, and strip specifications are all design nominal values, with no uncertainty interference. Robust reference limits are calibrated as follows: 1) Determine the core parameters of the reference pass: reference strip width Reference strip thickness Reference mill exit speed Reference rack exit speed ; 2) The maximum tension at the reference pass was calculated based on the tension stress theory model. The formula for calculating the maximum tension under the reference pass is:

[0022] in: The maximum tension is referenced for the specified track number. Allowable tensile stress, inherent property value of rolled material; For reference strip thickness ; For reference strip width ; 3) Based on the frame stiffness constraint, the AGC compensation amplitude is limited to obtain the maximum safe compensation amount of the AGC. The formula for calculating the maximum security compensation amount for AGC is: For the rigidity of the rolling mill stand; It should be noted that excessive AGC compensation can cause sudden changes in rolling force, exceeding the range that the frame stiffness can withstand. Therefore, the compensation amplitude is constrained by the frame stiffness. 4) Introduce a robust benchmark limit for the reference track for safety margin coefficient calibration. The formula for calculating the robust baseline limit for reference passes is as follows: η is the cold start safety margin coefficient, with a value ranging from 0.7 to 0.9; It should be noted that the safety margin coefficient η is introduced to offset the effects of uncertainties such as fluctuations in strip material and sensor measurement errors. S2 calculates the baseline limit under actual working conditions to achieve adaptive adaptation of variable specifications in headless continuous casting and rolling. For multi-specification switching scenarios in endless continuous casting and rolling, a dimensionless adaptive correction law is constructed based on the reference pass baseline limit HM0 calculated in step S1 to calculate the baseline limit under actual working conditions: 1) Collect real-time parameters of actual rolling conditions: actual strip thickness h Actual mill exit speed V L Actual rack exit speed V I Material modulus of strip steel under actual working conditions ; 2) Perform dimensionless deviation correction and stiffness matching correction for actual working conditions. The formula for correcting dimensionless deviation is: , in, For the actual strip thickness, For the actual mill exit speed, For actual rack exit speed, For reference strip thickness, For reference mill exit speed, For reference rack exit speed; The stiffness matching correction formula is as follows:

[0023] in, This is the material modulus of the strip steel under actual working conditions. For the rigidity of the rolling mill stand; 3) Output actual operating condition reference limits, The formula for calculating the reference limit under actual operating conditions is as follows:

[0024] .

[0025] It should be noted that the dimensionless deviation correction uses the reference pass condition as a benchmark. By normalizing the ratio of core parameters such as thickness and speed, a quantitative correlation between the actual working condition and the reference working condition is established. This ensures that the initial deviation of the benchmark limit under variable specification working conditions is within a reasonable range, providing a stable basis for adaptive correction. The stiffness matching correction can fully consider the synergistic effect of strip deformation and frame deformation, ultimately achieving automatic correction of the limit under variable specification working conditions, adapting to the seamless switching between thick and thin billets in endless continuous casting and rolling.

[0026] S3, multi-risk fuzzy collaborative control, achieves dynamic and precise optimization of limit values. To address the multi-parameter collaborative risks associated with tension, rolling force, and motor current in continuous casting and rolling, fuzzy control theory is employed to dynamically reduce the baseline limits under actual operating conditions, thus mitigating the limitations of single-parameter risk control. 1) Determine the fuzzy control input and output: The input is the relative deviation between the actual process parameters and the dangerous threshold (tension deviation rate, rolling force over-limit rate, motor current over-limit rate), and the output is the limit reduction coefficient in the 0~1 range; 2) Classification of Fuzzy Risk Levels: Input deviations are classified into four fuzzy levels: no risk, low risk, medium risk, and high risk. Tension is the deviation rate between the actual value and the set value; the smaller the deviation rate, the safer it is. Rolling force is divided into maximum deviation and minimum deviation, which are the deviation values ​​between the actual rolling force and the maximum / minimum rolling force, respectively; the smaller the deviation, the more dangerous it is. Motor current is the deviation value from the maximum current; the smaller the deviation, the more dangerous it is. A fuzzy rule base is established based on the hot rolling process (e.g., "Tension deviation rate 10% → low risk → reduction coefficient 0.7" "Rolling force over-limit rate 30% → high risk → reduction coefficient 0.2"); detailed rules are shown in Table 1. 3) Output reduction factor in each direction: The direction of increasing roll gap corresponds to the first reduction factor. The deviation is determined by three risk factors: the actual value of the inlet tension versus the set value, the actual value of the outlet tension versus the set value, and the actual value of the rolling force versus the minimum rolling force. These three deviation rates are then processed using fuzzy rules to obtain corresponding reduction coefficients, and the minimum value among the results is taken as the reduction coefficient. value; The direction of decreasing roll gap corresponds to the second reduction factor. The deviation is determined by four risk factors: the actual value of the inlet tension versus the set value, the actual value of the outlet tension versus the set value, the actual value of the rolling force versus the maximum rolling force, and the actual value of the main motor current versus the maximum value. These four deviation rates are reduced using fuzzy rules, and the minimum value among the results is taken as the minimum. value.

[0027] 4) Output risk control limit: Limit in the direction of increasing roll gap Limit of roll gap reduction direction To achieve precise adaptation to multiple risks; The principle of fuzzy control is as follows: When the reduction factor K When =0 (no risk), Use the original calculation rate to ensure AGC response speed; when the reduction factor... K When >0 (risky), Reduced proportionally to avoid further deterioration of tension / rolling force; It should be noted that this solution selects tension, rolling force, and motor current as key control parameters because these three constitute the most crucial safety constraint system in the endless continuous casting and rolling process. In other words, any abnormality in any of these parameters could lead to the most serious production accidents, therefore, they must be monitored and considered in a coordinated manner. Specifically, if the compensation amount of Automatic Thickness Control (AGC) is too large, it will directly cause a sudden change in rolling force, which in turn will induce violent fluctuations in tension between the stands. When the tension exceeds the allowable stress limit of the strip, it will directly lead to strip breakage; conversely, if the tension is too small, it may cause steel piling, which will also cause serious production interruptions and equipment damage. The most direct effect of AGC compensation is reflected in its impact on rolling force. If the rolling force exceeds the safe range allowed by the equipment, it may lead to serious consequences such as plastic deformation of the stand or damage to the support roll bearings. In addition, AGC directly changes the state of the rolling deformation zone by adjusting the roll gap, thereby affecting the rolling torque. When the load current of the drive motor exceeds its rated limit, it indicates that the motor may face fault risks such as stall, winding thermal overload, or inverter protective tripping.

[0028] S4, a safety hard limit, outputs the final roll gap adjustment speed limit. Introduce a hard limit SM0 (a hard constraint in equipment design, generally determined by the mill manufacturer and not to be exceeded) for the maximum allowable roll gap adjustment speed of the rolling mill equipment. This provides a safety net by clamping down on the limit after risk control, ensuring equipment safety. 1) Final limit clamping: Final limit in the direction of increasing roll gap Final limit in the direction of roll gap reduction ; 2) Limit output: SMP and SMN are output to the roll gap adjustment actuator as the upper limit of the safe speed in the direction of roll gap increase and decrease. The actuator adjusts the roll gap speed within the limit range to ensure production safety and efficiency.

[0029] Table 1

[0030] Example 1: This embodiment provides a method for controlling the rate of change of AGC control quantity in headless continuous casting and rolling, including the following steps: S1, based on the tension stress theory model, calculates the reference rate of compression under the reference pass; A typical specification from the rolling process is selected as the reference pass (nominal operating condition). Under this condition, the strip material, stand stiffness, and rolled piece specifications are all design nominal values, with no uncertainty interference. Robust reference limits are calibrated as follows: 1) The nominal rolling condition of Q235 strip steel in the endless continuous casting and rolling production is selected as the reference pass. This condition has no uncertainty interference. The strip steel material, stand stiffness and rolled piece specifications are all design nominal values. The core parameters and inherent characteristic values ​​are calibrated as shown in Table 2: Table 2

[0031] 2) Calculate the maximum tension under the reference track: , in: The maximum tension is referenced for the specified track number. Allowable tensile stress, inherent property value of rolled material; For reference strip thickness ; For reference strip width ; 3) Calculate the maximum safety compensation amount for AGC: , in, For the rigidity of the rolling mill stand; 4) Calculate the robust baseline limit for the reference track: , in, η is the cold start safety margin coefficient, with a value of 0.8. S2 calculates the baseline limit under actual working conditions to achieve adaptive adaptation of variable specifications in headless continuous casting and rolling. For multi-specification switching scenarios in endless continuous casting and rolling, a dimensionless adaptive correction law is constructed based on the reference pass baseline limit HM0 calculated in step S1 to calculate the baseline limit under actual working conditions: 1) During production, the process parameters and strip material modulus were collected in real time when switching to the Q235 strip thin-gauge rolling condition. The results are shown in Table 3. Table 3

[0032] 2) Calculate the dimensionless deviation correction factor K base-act

[0033] 3) Calculate the stiffness matching correction factor K stiff

[0034] 4) Calculate the actual operating condition reference limit HMcurrent

[0035] S3, multi-risk fuzzy collaborative control, achieves dynamic and precise optimization of limit values. To address the multi-parameter collaborative risks associated with tension, rolling force, and motor current in continuous casting and rolling, fuzzy control theory is employed to dynamically reduce the baseline limits under actual operating conditions, thus mitigating the limitations of single-parameter risk control. 1) Data collection of actual process parameter deviation rate (thin gauge rolling condition) The actual deviation rates of tension, rolling force, and motor current were collected in real time. Combined with the fuzzy rule library of hot rolling process, the corresponding risk level and reduction coefficient were matched. The results are shown in Table 4. Table 4

[0036] 2) Calculate the directional reduction factor; First reduction factor K1 in the direction of increasing roll gap: K1 is the minimum value of the reduction coefficients corresponding to the three sets of parameters: inlet tension deviation, outlet tension deviation, and actual rolling force / minimum rolling force deviation. It is calculated as follows: ; Second reduction factor K2 in the direction of roll gap reduction: K2 is the minimum value of the reduction coefficients corresponding to the four sets of parameters: inlet tension deviation, outlet tension deviation, actual rolling force / maximum rolling force deviation, and motor current deviation. It is calculated as follows: ; 3) Calculate the risk control limit; Roll gap increase direction limit P1: Calculation formula:

[0037] Calculation results:

[0038] Roll gap reduction direction limit P2: Calculation formula:

[0039] Calculation results: ; S4, Determine the final roll gap adjustment speed limit. 1) Hard limit settings for rolling mill equipment; The maximum speed limit for roll gap adjustment of this rolling mill equipment is specified by the manufacturer. This is an insurmountable design constraint for the equipment.

[0040] 2) Final limit clamping calculation; The final roll gap adjustment speed limit is taken as the smaller value between the risk control limit and the equipment hard limit, and the calculation formula is as follows: Final limit for the direction of roll gap increase: ; Final limit for the direction of roll gap reduction: ; In summary, this embodiment targets the rolling condition of Q235 strip steel thin specifications in a continuous casting and rolling production line. Through a four-level control strategy of robust benchmark limit calibration, adaptive correction under actual working conditions, multi-risk fuzzy control, and equipment hard limit fallback, the final adjustment speed limit of the AGC system in the direction of increasing roll gap is determined to be 0.0230 mm / s, and the final adjustment speed limit in the direction of decreasing roll gap is determined to be 0.0115 mm / s.

[0041] Example 2: This invention also provides a control device for the rate of change of AGC control quantity in endless continuous casting and rolling, such as... Figure 2 As shown, the device includes a processor 201, a memory 202, a bus 203, and a computer program stored in the memory 202 and executable on the processor 201. The processor 201 includes one or more processing cores. The memory 202 is connected to the processor 201 via the bus 203. The memory 202 is used to store program instructions. When the processor executes the computer program, it implements the steps in the above-described method embodiment of Embodiment 1 of the present invention.

[0042] Furthermore, as an executable solution, the control device can be a computer unit, which can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. The computer unit may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the above-described structure of the computer unit is merely an example and does not constitute a limitation on the computer unit. It may include more or fewer components, or combine certain components, or use different components. For example, the computer unit may also include input / output devices, network access devices, buses, etc., and this embodiment of the invention does not limit this.

[0043] Furthermore, as an executable solution, the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The processor is the control center of the computer unit, connecting various parts of the entire computer unit via various interfaces and lines.

[0044] The memory can be used to store the computer programs and / or modules. The processor implements various functions of the computer unit by running or executing the computer programs and / or modules stored in the memory and by calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function; the data storage area may store data created based on the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital card (SD card), flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A control method of a control amount change rate of an endless casting and rolling AGC, characterized by, Includes the following steps: S1, calibrating robust reference limits; S2, based on the robust reference limit mentioned in step S1, and performing dimensionless deviation correction and stiffness matching correction on the actual working conditions, the reference limit for the actual working conditions is calculated. S3, using fuzzy control theory, the actual working condition baseline limit obtained in step S2 is reduced to obtain the risk control post-limit; S4. Compare the risk control limit obtained in step S3 with the maximum allowable roll gap adjustment speed hard limit of the rolling mill equipment, and select the smaller value of the two as the final roll gap adjustment speed limit.

2. The control method according to claim 1, characterized by, In step S1, the method for calibrating the robust reference limit is as follows: First, a typical specification with strip material, frame stiffness, and specifications that are all design nominal values ​​and have no uncertainty interference is selected as a reference pass. Then, based on the core parameters of the reference pass, the maximum tension under the reference pass is calculated based on the tension stress theory model. The maximum safe compensation amount of AGC is obtained by limiting the amplitude of AGC compensation based on the frame stiffness constraint. Finally, the robust reference limit of the reference pass is obtained by introducing the safety margin coefficient.

3. The control method according to claim 2, characterized in that, The core parameter for the reference pass is the reference strip width. Reference strip thickness Reference mill exit speed Reference rack exit speed .

4. The control method according to claim 2, characterized in that, The formula for calculating the maximum tension under the reference pass is: in: The maximum tension is referenced for the specified track number. Allowable tensile stress, inherent property value of rolled material; For reference strip thickness ; For reference strip width ; The formula for calculating the maximum safety compensation amount of AGC is as follows: For the rigidity of the rolling mill stand; The robust baseline limit for the reference track is calculated using the following formula: η is the cold start safety margin coefficient, with a value of 0.7 to 0.

9.

5. The control method according to claim 1, characterized in that, In step S2, The dimensionless deviation correction formula is as follows: ， in, For actual strip thickness, For the actual mill exit speed, For actual rack exit speed, For reference strip thickness, For reference mill exit speed, For reference rack exit speed; The stiffness matching correction formula is as follows: in, This refers to the material modulus of the strip steel under actual working conditions. For the rigidity of the rolling mill stand; The formula for calculating the actual operating condition reference limit is as follows: 。 6. The control method according to claim 1, characterized in that, In step S3, the specific implementation of the fuzzy control theory is as follows: First, the relative deviation between the actual process parameters and the danger threshold is determined as the input term of the fuzzy control, and the limit reduction coefficient in the 0~1 interval is the output term of the fuzzy control; second, the input term is divided into four fuzzy levels: no risk, low risk, medium risk, and high risk, and a fuzzy rule base is established based on the hot rolling process; third, the reduction coefficient is output in different directions, with the direction of increasing roll gap corresponding to the first reduction coefficient. K 1. The direction of decreasing roll gap corresponds to the second reduction factor. Finally, output the risk control limit value and the limit value in the direction of increasing roll gap. Limit of roll gap reduction direction ,in, .

7. The control method according to claim 6, characterized in that, The inputs for the fuzzy control are tension deviation rate, rolling force over-limit rate, and motor current over-limit rate.

8. The control method according to claim 6, characterized in that, First reduction coefficient K 1 represents the minimum value among the three sets of deviation rates—the deviation between the actual and set values ​​of the inlet tension, the deviation between the actual and set values ​​of the outlet tension, and the deviation between the actual and minimum rolling force—obtained through fuzzy rules.

9. The control method according to claim 6, characterized in that, Second reduction factor K 2 represents the minimum value among the four sets of deviation rates—the deviation between the actual and set values ​​of the inlet tension, the deviation between the actual and set values ​​of the outlet tension, the deviation between the actual and maximum rolling force, and the deviation between the actual and maximum values ​​of the main motor current—obtained through fuzzy rules.

10. A control device for the rate of change of AGC control quantity in headless continuous casting and rolling, characterized in that, include: A memory and a processor, the memory storing at least one program, the at least one program being executed by the processor to implement the method as claimed in any one of claims 1 to 9.

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