Method and system for controlling thickness of hot continuous rolling finishing mill group

Abstract

The invention provides a method for controlling the thickness of a hot continuous rolling finishing mill group, which comprises the following steps of: S1, setting an embedded roll gap according to secondary model data corresponding to a strip steel threading thickness specification; s2, when the strip head of the strip steel penetrates through the rack, head impact compensation is conducted; s3, when the strip steel does not pass through an outlet of the hot continuous rolling finishing mill group, a rolling force AGC roll gap compensation value is calculated through rolling force AGC, and roll gap compensation is conducted on the hot continuous rolling finishing mill group; s4, when the strip steel passes through an outlet of the hot continuous rolling finishing mill group, the AGC roll gap compensation value is calculated and monitored according to the strip steel thickness detected at the outlet; and according to the monitoring AGC roll gap compensation value and the rolling force AGC roll gap compensation value, roll gap compensation is conducted on the hot continuous rolling finishing mill group. Through closed-loop control of the rolling force AGC function and the monitoring AGC function and in cooperation with the head punching compensation function, high-precision control over the thickness of materials at an outlet of the rolling mill can be achieved from the very short distance of the head of the strip steel.

Description

Technical Field

[0001] The present invention relates to the field of electrical automation control technology, in particular to a method and system for controlling the thickness of a hot rolling finishing mill, and in particular to a method and system for controlling the thickness of a hot rolling finishing mill with high precision. Background Art

[0002] At present, the thickness accuracy of hot rolling enterprises is 30-50um. However, the deviation of the head thickness is usually poor, sometimes up to 150-200um, and it takes a long time to reach the stable area. Therefore, the rolled products often need to cut off the part with large head thickness deviation before they can be sent to downstream customers, resulting in waste of resources and increased costs. However, with the increasing market requirements for the quality of hot-rolled products, the ability to roll products with high-precision thickness will provide enterprises with an opportunity to seize the market and win greater profits. Therefore, it is very necessary to develop a technology that can stably control the thickness of the strip at the mill outlet starting from the strip head.

[0003] The patent document with the publication number CN110538881A discloses a hot rolling thickness control method based on an improved internal mold controller, including: establishing a mathematical model of the hydraulic roll gap control system (HGC) of the stand, and using the particle swarm optimization algorithm (PSO) to identify the HGC system model; based on this model, designing a traditional internal mold monitoring AGC controller, and improving the traditional internal mold monitoring AGC controller to make it a two-degree-of-freedom controller; introducing an iterative learning algorithm into the monitoring AGC system based on the improved internal mold controller. This invention patent uses an internal mold controller to achieve high-precision adjustment of the monitoring AGC, but does not take into account the entire process of strip rolling, especially the control of the thickness of the strip head, and cannot guarantee the thickness accuracy of the strip head.

[0004] Therefore, it is necessary to develop a high-precision thickness control technology to improve the quality of hot-rolled finished products and meet the high demands of downstream customers. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a method and system for thickness control of a hot rolling finishing mill.

[0006] A method for controlling thickness of a hot rolling finishing mill group provided by the present invention comprises:

[0007] Step S1: setting the embedded roll gap according to the secondary model data corresponding to the strip threading thickness specification;

[0008] Step S2: When the strip head of the strip passes through the frame, head impact compensation is performed;

[0009] Step S3: before the strip steel passes through the outlet of the hot rolling finishing mill, the rolling force AGC roll gap compensation value is calculated by the rolling force AGC, and the roll gap compensation is performed on the hot rolling finishing mill;

[0010] Step S4: When the strip passes through the exit of the hot rolling finishing mill, the AGC roll gap compensation value is calculated based on the strip thickness detected at the exit; and the roll gap compensation is performed on the hot rolling finishing mill based on the AGC roll gap compensation value and the rolling force AGC roll gap compensation value.

[0011] Preferably, step S2 comprises:

[0012] When the head of the strip passes through the frame instantaneously, an impact is generated, causing the roll gap to change. The change in the roll gap is set as the initial value of the head impact compensation, and then the initial value is adjusted according to the head thickness measured at the outlet of the finishing mill to perform head impact compensation.

[0013] Preferably, step S3 includes:

[0014] Calculate the rolling force AGC roll gap compensation value, including:

[0015] According to the characteristics of the rack, set the material deformation coefficient Qn and the rack elastic coefficient M of the rack n ; According to the actual situation, set the gain coefficient G of the rolling force AGC;

[0016] Calculate the exit thickness latch value:

[0017] h n0 =S n0 +h fn F n0

[0018] Calculate the predicted outlet thickness:

[0019] h n =S n +h fn F n

[0020] Calculate the predicted thickness deviation Δh at the outlet n :

[0021] Δh n =h n -h n0 =S n -S n0 +h fn F n 1h fn F n0

[0022] Calculate the rolling force AGC roll gap compensation value ΔS n *:

[0023]

[0024] In the above formula:

[0025] S n0 is the roll gap lock value; h n0 F is the exit thickness latch value; n0 is the rolling force lock value; S n is the actual roll gap value; h n is the predicted outlet thickness; F n is the actual rolling force; h fn is the rolling mill bounce curve equation.

[0026] Preferably, step S4 comprises:

[0027] Calculate and monitor AGC roll gap compensation value, including:

[0028] According to the actual situation, set the gain coefficient G of the monitoring AGC respectively. mon , PI controller coefficient K, integral time T S , the time constant T between racks 0i and the running time T from the i-th rolling mill Fi to the X-ray thickness gauge i ;

[0029] The specific formula is:

[0030]

[0031] In the above formula:

[0032] ΔS n1 * To monitor the AGC roll gap compensation value; Δh x It is the thickness deviation measured by the outlet thickness gauge.

[0033] Preferably, the compensation process in step S4 includes:

[0034] ΔS total * =ΔS n * +ΔS n1 *

[0035] ΔS total * is the roller gap compensation value.

[0036] A system for controlling thickness of a hot rolling finishing mill group provided by the present invention comprises:

[0037] Module M1: Set the embedded roll gap according to the secondary model data corresponding to the strip threading thickness specification;

[0038] Module M2: When the strip head passes through the frame, head impact compensation is performed;

[0039] Module M3: When the strip steel has not passed through the outlet of the hot rolling finishing mill, the rolling force AGC roll gap compensation value is calculated by the rolling force AGC, and the roll gap compensation is performed on the hot rolling finishing mill;

[0040] Module M4: When the strip passes through the exit of the hot rolling finishing mill, the AGC roll gap compensation value is calculated based on the strip thickness detected at the exit; the roll gap compensation is performed on the hot rolling finishing mill based on the AGC roll gap compensation value and the rolling force AGC roll gap compensation value.

[0041] Preferably, module M2 comprises:

[0042] When the head of the strip passes through the frame instantaneously, an impact is generated, causing the roll gap to change. The change in the roll gap is set as the initial value of the head impact compensation, and then the initial value is adjusted according to the head thickness measured at the outlet of the finishing mill to perform head impact compensation.

[0043] Preferably, the execution process of module M3 is as follows:

[0044] Calculate the rolling force AGC roll gap compensation value, including:

[0045] According to the rack characteristics, set the rack material plastic deformation coefficient Q n and the frame elastic coefficient M n ; According to the actual situation, set the gain coefficient G of the rolling force AGC;

[0046] Calculate the exit thickness latch value:

[0047] h n0 =S n0 +h fn F n0

[0048] Calculate the predicted outlet thickness:

[0049] h n =S n +h fn F n

[0050] Calculate the predicted thickness deviation Δh at the outlet n :

[0051] Δh n =h n -h n0 =S n -S n0 +h fn F n-h fn F n0

[0052] Calculate the rolling force AGC roll gap compensation value ΔS n * :

[0053]

[0054] In the above formula:

[0055] S n0 is the roll gap lock value; h n0 F is the exit thickness latch value; n0 is the rolling force lock value; S n is the actual roll gap value; h n is the predicted outlet thickness; F n is the actual rolling force; h fn is the rolling mill bounce curve equation.

[0056] Preferably, the execution process of module M4 is as follows:

[0057] Calculate and monitor AGC roll gap compensation value, including:

[0058] According to the actual situation, set the gain coefficient G of the monitoring AGC respectively. mon , PI controller coefficient K, integral time T S , the time constant T between racks 0i and the running time T from the i-th rolling mill Fi to the X-ray thickness gauge i ;

[0059] The specific formula is:

[0060]

[0061] In the above formula:

[0062] ΔS n1 * To monitor the AGC roll gap compensation value; Δh x It is the thickness deviation measured by the outlet thickness gauge.

[0063] Preferably, the roller gap compensation process in module M4 is as follows:

[0064] ΔS total * =ΔS n * +ΔS n1 *

[0065] ΔS total * is the roller gap compensation value.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] 1. The present invention realizes a high-precision control technology for the thickness of the material at the mill outlet starting from a very short distance from the strip head through the closed-loop control of the rolling force AGC and the monitoring AGC function and in conjunction with the head impact compensation function;

[0068] 2. The present invention develops and optimizes a high-precision thickness control method, combined with head impact compensation energy supply, which can improve the thickness control accuracy and form a complete thickness control system, so that the hot rolling production line has the ability to improve the yield rate and produce high-end products;

[0069] 3. The present invention realizes high-precision thickness control through the head rush compensation of the finishing mill group and the closed-loop control of the rolling force AGC and the monitoring AGC. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0071] Figure 1 It is a schematic flow chart of a method for controlling thickness of a hot rolling finishing mill group according to the present invention;

[0072] Figure 2 This is a schematic diagram of the process of Example 1 of the present invention. DETAILED DESCRIPTION

[0073] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0074] The present invention aims to solve the problem of low thickness accuracy of finished products in hot rolling enterprises. By developing and optimizing a high-precision thickness control technology, the thickness of the outlet material can be set to a very high accuracy starting from a short distance from the head of the strip, thereby enabling the hot rolling production line to have the ability to improve the yield rate and produce high-end products.

[0075] High-precision thickness control technology solution:

[0076] High-precision thickness control is achieved through the closed-loop control functions of the rolling force thickness automatic control (AGC) and the monitoring thickness automatic control (AGC) integrated in the automation control system of the finishing mill and in conjunction with the head rush compensation function: the speed, roll gap and exit thickness data calculated by the secondary model corresponding to the strip threading thickness specification of each frame of the finishing mill are set. During the steel biting process of the rolling mill, the roll gap change caused by the instantaneous impact of the rolling mill is compensated by the pre-embedded roll gap. Then, the rolling force AGC needs to be activated in time to quickly compensate for the change in frame stretching according to the change in rolling force. After the strip threading of the unit is completed and the strip is detected by the unit exit thickness gauge, the finishing mill monitoring AGC uses the actual thickness deviation as the setting for closed-loop control, and the monitoring AGC controls all frames of the finishing mill to adjust the roll gap at the same time.

[0077] Step 1: Rolling force AGC compensation

[0078] When the rolling mill is calibrated, the rolling force and roll gap position at that time are locked and stored, and used as the relative reference point for subsequent control. Among them, the thickness automatic control AGC (Automatic Gauge Control).

[0079] The rolling force is calculated by the spring equation. When the parameters are locked, the exit thickness at this moment is saved as the standard value. Then, according to the change of rolling force and the change of rolling force in the subsequent rolling process, the change of exit strip thickness is calculated, and the roll gap is adjusted according to the change of this exit thickness. Specifically, the rolling pressure deviation and the thickness deviation Δh1 caused by different width factors are measured by the pressure gauge and converted into the roll gap deviation value through the spring equation. The change of the roll gap position ΔS1 is measured according to the position feedback, and the deviation is fed back to the thickness automatic control device for adjustment.

[0080] In the present invention, the compensation amount of the rolling force AGC system is adjusted by the rolling force AGC gain coefficient G. The system can adjust the corresponding parameters according to different steel grades or layers to achieve the best control effect.

[0081] Since the rolling force AGC is an instant response control method with less delay time, it has a better effect in eliminating thickness deviation caused by uneven temperature.

[0082] The specific formula is:

[0083] Calculate the exit thickness latch value:

[0084] h n0 =S n0 +h fn F n0

[0085] Calculate the predicted outlet thickness:

[0086] hn =S n +h fn F n

[0087] Calculate the predicted thickness deviation Δh at the outlet n :

[0088] Δh n =h n -h n0 =S n -S n0 +h fn F n -h fn F n0

[0089] Calculate the rolling force AGC roll gap compensation value ΔS n * :

[0090]

[0091] In the above formula:

[0092] s n0 is the roll gap lock value; h n0 F is the exit thickness latch value; n0 is the rolling force lock value; S n is the actual roll gap value; h n is the predicted outlet thickness; F n is the actual rolling force; h fn is the rolling mill bounce curve equation; G is the gain coefficient of rolling force AGC; Qn is the material plastic deformation coefficient; M n is the frame elastic coefficient.

[0093] Among them, the rolling mill bounce curve equation is specifically that the rolling mill produces elastic deformation after being subjected to force, which causes the change of the roll gap, reflecting the changing relationship between force and roll gap. Specifically, it can be approximately considered that h fn K is the elastic deformation of the roll gap after being stressed, r is the rolling mill stiffness coefficient, and P is the rolling force.

[0094] Step 2: Monitor AGC Compensation

[0095] Since the indirect thickness measurement method has the disadvantage of low accuracy, a relatively high-precision thickness gauge is installed on the outlet side of the last stand of the finishing mill to detect the actual thickness deviation Δh2 of the finished steel plate, which is fed back to the thickness automatic control system of each stand and compared with the given target thickness (i.e. target thickness) value. When the two values ​​are equal, the thickness gauge output is zero (the output of the thickness gauge is the thickness deviation value Δh2), i.e. Δh2 = 0. If the measured thickness value is not equal to the given target thickness and a thickness deviation Δh2 occurs, the Δh2 is fed back to the thickness automatic control device for roll gap adjustment. The characteristics of this AGC system are: the detection amount and the control amount of the thickness change do not occur at the same time (because the thickness gauge is a certain distance from the center line of the working roll of the last stand), so when the thickness fluctuation detected at the detection point cannot be reflected in time, there is a certain lag time.

[0096] In the present invention, the gain coefficient G of the monitoring AGC is increased. mon The compensation amount of the monitoring AGC is adjusted by the coefficient K of the PI controller. The system can adjust the corresponding parameters according to different steel grades or layers to achieve the best control effect.

[0097] The specific formula is:

[0098]

[0099] In the above formula:

[0100] ΔS n1 * To monitor the AGC roll gap compensation value; Δh x is the thickness deviation measured by the outlet thickness gauge; T 0i is the time constant between racks, in seconds; T i is the running time from the i-th rolling mill Fi to the X-ray thickness meter, in seconds; K is the PI controller coefficient; T S is the integration time; G mon is the gain coefficient; Q n M is the plastic deformation coefficient of the material; n is the frame elastic coefficient.

[0101] Step 3: Head Impact Compensation

[0102] When the strip head passes through the stand, due to the sudden change of the roll gap caused by the instantaneous rolling force change, sufficient control is impossible only in the rolling force AGC mode, and the strip thickness at the entrance of the next stand will inevitably increase. The head impact compensation value is generally predicted in the following way. First, the initial value is set according to the change in the roll gap caused by the impact of the rolling mill biting the steel (generally, 60% of the roll gap change is taken as the initial setting of the impact compensation), and then the head thickness deviation measured by the thickness gauge after the finishing mill is appropriately adjusted. The head impact compensation gives a forced pressure reduction amount to compensate for the thickness of the strip head according to the prediction, that is, the head impact compensation amount IDC. Although the compensation function starts when the previous stand bites the steel, in the downstream stand, as the strip speed increases, the effective control time of the strip will be shortened, and there is a certain delay in the control, so the control effect in the downstream will be reduced.

[0103] Step 4: The overall high-precision thickness control is achieved by integrating the closed-loop control function of the rolling force AGC and the monitoring AGC in conjunction with the head rush compensation function.

[0104] Calculate the roller gap compensation value ΔS total * :

[0105] ΔS total * =ΔS n * +ΔS n1 *

[0106] Through the roll gap compensation equation, the roll gap compensation value can be adjusted in real time to adjust the roll gap and improve the rolling effect.

[0107] The present invention receives the impact compensation setting value from the secondary machine and feeds back the actual roll gap change to the secondary machine during the rolling mill biting process, so that an optimal impact compensation setting can be obtained through continuous learning and optimization, which effectively solves the problem of large thickness deviation of the head.

[0108] Example 1

[0109] Normally, the strip with an outlet thickness of 1.5 mm is rolled. Taking the last stand of the rolling mill as an example, the additional roll gap value is ΔS total * ;

[0110] Step 1: The secondary model converts the material plastic deformation coefficient Q of the rack n and the frame elastic coefficient M n Automatic control system, where the frame elastic coefficient M nIt is a nonlinear function of rolling force and rolling mill deformation calculated based on the rolling mill stiffness test. The material plastic deformation coefficient Qn is calculated based on the chemical composition of different materials. In this example, the frame elastic coefficient M n =5700KN / mm, material plastic deformation coefficient Q n =22000KN / mm;

[0111] Step 2: The secondary model sends different head impact compensation amounts and set values ​​to the automatic control system according to the different hardness levels of the rolled steel. In this example, the head impact compensation amount IDC = -120um;

[0112] Step 3: Set the rolling force AGC gain coefficient G = 0.90 in the automatic control system and monitor the AGC gain coefficient G mon =0.95, PI controller coefficient K for monitoring AGC = 0.1, integral time T S =500ms, time constant T between racks 0i = 0.45s, the running time T from the i-th rolling mill Fi to the X-ray thickness meter i =0.32s;

[0113] Step 4: When the strip is set at the entrance of the finishing mill, the automation system receives the head impact compensation value IDC = -120um, then the roll gap additional value at this time is ΔS total * =IDC=-120um, the mill roll gap is closed by 120um to wait for the strip to enter. When the strip head enters the mill, and the actual rolling force measured by the rolling force detection device reaches 70% of the rolling force set by the secondary model, the head impact compensation amount IDC=0um is switched according to the internal logic, and the roll gap additional value at this time is ΔS total * =IDC=0um. The change of this set value completes the action of adding roll gap through the position slope of the position controller set in the automatic control system, so that the change of roll gap in the opening process just offsets the change of roll gap caused by the roll gap impact in the steel biting process, ensuring that the thickness of the strip head is minimally affected by the mechanical equipment.

[0114] Step 5: When the rolling force AGC performs parameter locking after the impact compensation is completed (500ms after the steel bite signal is triggered), the roll gap lock value S at this time is saved. n0 and rolling force latch value F n0 Then, the strip exit thickness latch value is calculated based on the mill bounce curve issued by the secondary model, and the exit thickness latch value is saved as the standard value of the controller. The calculation is performed using the following formula:

[0115] h n0 =Sn0 +h fn F n0

[0116] Since the mill bounce curve issued by the secondary model will have different values ​​depending on the rolling force, a simplified treatment is made here, that is, it is assumed that h calculated according to the relevant parameters n0 =1.4mm.

[0117] Then, according to the change of rolling force and the change of rolling force in the subsequent rolling process, the change of the thickness of the export strip is calculated, and the export thickness is predicted according to the following formula:

[0118] h n =S n +h fn F n

[0119] Similarly, it is assumed here that h calculated based on the relevant parameters n =1.3mm.

[0120] Based on the above, the export predicted thickness deviation value can be calculated as:

[0121] Δh n =h n -h n0 =1.3-1.4=-0.1mm

[0122] According to this, the strip exit thickness deviation value can be converted into the actual rolling force AGC roll gap deviation value of the rolling mill through the formula, and because there is actually a delay in the press-down system, it should be multiplied by the gain coefficient. The specific calculation is as follows:

[0123]

[0124] This calculated value is added to the roll gap setting value of the rolling mill, that is, ΔS total * =0.437mm. This process will be calculated in real time according to the change of actual rolling force and the actual rolling force change in the subsequent rolling process.

[0125] Step 6: After the strip head passes through the thickness gauge, when the thickness gauge stably detects the strip thickness deviation, it delays 150ms and starts the monitoring AGC. The monitoring AGC uses the measurement data of the X-ray thickness gauge at the finishing exit to correct the actual exit thickness through the PI controller to obtain the absolute thickness value. Assume that the thickness deviation Δh measured by the exit thickness gauge is x =60um, the AGC roll gap compensation value can be calculated by the following formula:

[0126]

[0127]

[0128] Step 7: According to the coordinated action of rolling force AGC and monitoring AGC, the stable thickness of the rolling outlet material can be quickly and accurately controlled. The above calculation can be used to obtain the mill roll gap compensation value:

[0129] ΔS total * =ΔS n * +ΔS n1 * =0.437+0.117=0.554mm

[0130] Therefore, the rolling mill roll gap compensation value is 0.554mm at this moment.

[0131] It should be noted that the roll gap compensation value is cleared when the AGC monitoring ends.

[0132] The present invention also provides a system for controlling the thickness of a hot rolling finishing mill group. The system for controlling the thickness of a hot rolling finishing mill group can be realized by executing the process steps of the method for controlling the thickness of a hot rolling finishing mill group, that is, those skilled in the art can understand the method for controlling the thickness of a hot rolling finishing mill group as a preferred implementation of the system for controlling the thickness of a hot rolling finishing mill group.

[0133] A system for thickness control of a hot rolling finishing mill group comprises: a module M1: setting a pre-buried roll gap according to secondary model data corresponding to the strip threading thickness specification; a module M2: performing head impact compensation when the strip head passes through a frame; a module M3: calculating a rolling force AGC roll gap compensation value by a rolling force AGC before the strip has passed through the outlet of the hot rolling finishing mill group, and performing roll gap compensation on the hot rolling finishing mill group; a module M4: calculating a monitoring AGC roll gap compensation value according to the strip thickness detected at the outlet when the strip passes through the outlet of the hot rolling finishing mill group; and performing roll gap compensation on the hot rolling finishing mill group according to the monitoring AGC roll gap compensation value and the rolling force AGC roll gap compensation value.

[0134] Specifically, module M2 includes: when the strip head passes through the frame instantaneously, an impact is generated, causing the roll gap to change, the change in the roll gap is set as the initial value of the head impact compensation, and then the initial value is adjusted according to the head thickness measured at the outlet of the finishing mill to perform head impact compensation.

[0135] Specifically, the execution process of module M3 is as follows: Calculate the rolling force AGC roll gap compensation value, including: according to the characteristics of the frame, set the material plastic deformation coefficient Q of the frame n and the frame elastic coefficient M n; According to the actual situation, set the gain coefficient G of the rolling force AGC; calculate the exit thickness latch value:

[0136] h n0 =S n0 +h fn F n0

[0137] Calculate the predicted outlet thickness:

[0138] h n =S n +h fn F n

[0139] Calculate the predicted thickness deviation Δh at the outlet n :

[0140] Δh n =h n -h n0 =S n -S n0 +h fn F n -h fn F n0

[0141] Calculate the rolling force AGC roll gap compensation value ΔS n * :

[0142]

[0143] In the above formula: S n0 is the roll gap lock value; h n0 F is the exit thickness latch value; n0 is the rolling force lock value; S n is the actual roll gap value; h n is the predicted outlet thickness; F n is the actual rolling force; h fn is the rolling mill bounce curve equation.

[0144] Specifically, the execution process of module M4 is as follows: Calculate and monitor the AGC roll gap compensation value, including:

[0145] According to the actual situation, set the gain coefficient G of the monitoring AGC respectively. mon , PI controller coefficient K, integral time T S , the time constant T between racks 0i and the running time T from the i-th rolling mill Fi to the X-ray thickness gauge i ;

[0146] The specific formula is:

[0147]

[0148] In the above formula:

[0149] ΔS n1 * To monitor the AGC roll gap compensation value; Δh x It is the thickness deviation measured by the outlet thickness gauge.

[0150] Specifically, the roller gap compensation process in module M4 is as follows:

[0151] ΔS total * =ΔS n * +ΔS n1 *

[0152] ΔS total * is the roller gap compensation value.

[0153] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0154] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for controlling thickness of a hot rolling finishing mill, characterized in that: include: Step S1: setting the embedded roll gap according to the secondary model data corresponding to the strip threading thickness specification; Step S2: When the strip head of the strip passes through the frame, head impact compensation is performed; Step S3: before the strip steel passes through the outlet of the hot rolling finishing mill, the rolling force AGC roll gap compensation value is calculated by the rolling force AGC, and the roll gap compensation is performed on the hot rolling finishing mill; Step S4: When the strip passes through the exit of the hot rolling finishing mill, the AGC roll gap compensation value is calculated based on the strip thickness detected at the exit; and the roll gap compensation is performed on the hot rolling finishing mill based on the AGC roll gap compensation value and the rolling force AGC roll gap compensation value.

2. The method for controlling thickness of a hot rolling finishing mill according to claim 1, characterized in that: The step S2 comprises: When the head of the strip passes through the frame instantaneously, an impact is generated, causing the roll gap to change. The change in the roll gap is set as the initial value of the head impact compensation, and then the initial value is adjusted according to the head thickness measured at the outlet of the finishing mill to perform head impact compensation.

3. The method for controlling thickness of a hot rolling finishing mill according to claim 1, characterized in that: The step S3 comprises: Calculate the rolling force AGC roll gap compensation value, including: According to the rack characteristics, set the rack material plastic deformation coefficient Q n and the frame elastic coefficient M n ; According to the actual situation, set the gain coefficient G of the rolling force AGC; Calculate the exit thickness latch value: h n0 =S n0 +h fn F n0 Calculate the predicted outlet thickness: h n =S n +h fn F n Calculate the predicted thickness deviation Δh at the outlet n : Δh n =h n -h n0 =S n -S n0 +h fn F n -h fn F n0 Calculate the rolling force AGC roll gap compensation value ΔS n * : In the above formula: S n0 is the roll gap lock value; h n0 F is the exit thickness latch value; n0 is the rolling force lock value; S n is the actual roll gap value; h n is the predicted outlet thickness; F n is the actual rolling force; h fn is the rolling mill bounce curve equation.

4. The method for controlling thickness of a hot rolling finishing mill according to claim 1, characterized in that: The step S4 comprises: Calculate and monitor AGC roll gap compensation value, including: According to the actual situation, set the gain coefficient G of the monitoring AGC respectively. mon , PI controller coefficient K, integral time T S , the time constant T between racks 0i and the running time T from the i-th rolling mill Fi to the X-ray thickness gauge i ; The specific formula is: In the above formula: ΔS n1 * To monitor the AGC roll gap compensation value; Δh x It is the thickness deviation measured by the outlet thickness gauge.

5. The method for controlling thickness of a hot rolling finishing mill according to claim 1, characterized in that: The compensation process in step S4 includes: ΔS total * =ΔS n * +ΔS n1 * ΔS total * is the roller gap compensation value.

6. A system for controlling thickness of a hot rolling finishing mill, characterized in that: include: Module M1: Set the embedded roll gap according to the secondary model data corresponding to the strip threading thickness specification; Module M2: When the strip head passes through the frame, head impact compensation is performed; Module M3: When the strip steel has not passed through the outlet of the hot rolling finishing mill, the rolling force AGC roll gap compensation value is calculated by the rolling force AGC, and the roll gap compensation is performed on the hot rolling finishing mill; Module M4: When the strip passes through the exit of the hot rolling finishing mill, the AGC roll gap compensation value is calculated based on the strip thickness detected at the exit; the roll gap compensation is performed on the hot rolling finishing mill based on the AGC roll gap compensation value and the rolling force AGC roll gap compensation value.

7. The system for controlling thickness of hot rolling finishing mill according to claim 6, characterized in that: The module M2 comprises: When the head of the strip passes through the frame instantaneously, an impact is generated, causing the roll gap to change. The change in the roll gap is set as the initial value of the head impact compensation, and then the initial value is adjusted according to the head thickness measured at the outlet of the finishing mill to perform head impact compensation.

8. The system for controlling thickness of hot rolling finishing mill according to claim 6, characterized in that: The execution process of the module M3 is as follows: Calculate the rolling force AGC roll gap compensation value, including: According to the rack characteristics, set the rack material plastic deformation coefficient Q n and the frame elastic coefficient M n ; According to the actual situation, set the gain coefficient G of the rolling force AGC; Calculate the exit thickness latch value: h n0 =S n0 +h fn F n0 Calculate the predicted outlet thickness: h n =S n +h fn F n Calculate the predicted thickness deviation Δh at the outlet n : Δh n =h n -h n0 =S n -S n0 +h fn F n -h fn F n0 Calculate the rolling force AGC roll gap compensation value ΔS n * : In the above formula: S n0 is the roll gap lock value; h n0 F is the exit thickness latch value; n0 is the rolling force lock value; S n is the actual roll gap value; h n is the predicted outlet thickness; F n is the actual rolling force; h fn is the rolling mill bounce curve equation.

9. The system for controlling thickness of hot rolling finishing mill according to claim 6, characterized in that: The execution process of the module M4 is as follows: Calculate and monitor AGC roll gap compensation value, including: According to the actual situation, set the gain coefficient G of the monitoring AGC respectively. mon , PI controller coefficient K, integral time T S , the time constant T between racks 0i and the running time T from the i-th rolling mill Fi to the X-ray thickness gauge i ; The specific formula is: In the above formula: ΔS n1 * To monitor the AGC roll gap compensation value; Δh x It is the thickness deviation measured by the outlet thickness gauge.

10. The system for controlling thickness of hot rolling finishing mill group according to claim 6, characterized in that: The roller gap compensation process in the module M4 is as follows: ΔS total * =ΔS n * +ΔS n1 * ΔS total * is the roller gap compensation value.

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