Method for controlling liquid level height of thin-strip continuous casting molten pool

Abstract

The invention belongs to the technical field of metallurgical continuous casting, and relates to a method for controlling the liquid level height of a thin-strip continuous casting molten pool. The core of the method is that a fuzzy controller is adopted, and the input of the fuzzy controller is height deviation and change rate of molten pool liquid level. The control process comprises the following steps that firstly, the system is started, and a target liquid level is set; then, the liquid level height is measured in real time through a sensor, the deviation and the deviation change rate are calculated, and fuzzification is conducted on the deviation and the deviation change rate; then, reasoning operation is carried out based on a preset fuzzy rule, and a fuzzy output quantity is obtained and is sharpened; and finally, converting the clear value into a control signal to drive an execution mechanism so as to adjust the liquid level height. By continuously repeating the process, stable control over the liquid level height is achieved, and the liquid level height is made to be constant at a target value till production is finished.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metallurgical continuous casting, and relates to a method for controlling the liquid level height of a thin strip continuous casting bath. More particularly, the present application relates to setting a program of a programmable controller to drive an actuator to act, so as to realize accurate control of the liquid level height of the thin strip continuous casting bath. BACKGROUND

[0002] Double-roller thin strip continuous casting is a near-net-shape forming technology for metal thin strips. Double-roller thin strip continuous casting adopts two water-cooled rollers as a moving crystallizer. In the process of double-roller thin strip continuous casting, the liquid level height of the bath affects the heat transfer process between the metal melt and the crystallizer, thereby affecting the solidification process of the metal melt. Realizing a specific bath height and maintaining the stability of the bath height are crucial to the quality of the continuous casting metal thin strips, and therefore, the liquid level height of the bath needs to be accurately controlled.

[0003] In the process of vertical double-roller thin strip continuous casting, the inlet flow of the thin strip continuous casting bath is controlled by the action of a stopper in a tundish, and there is prior art about the control method of the liquid level height of the bath. However, the current control of the liquid level height of the thin strip continuous casting bath still has at least the following problems which have not been solved:

[0004] (1) Due to system disturbance, an overshoot may occur in the continuous casting process. The overshoot not only causes the liquid level height of the bath to suddenly rise, affecting the stability of the product quality, but also may cause the overflow of the steel melt.

[0005] (2) Even if a controller is built, the controller parameters as the elements of the controller will directly affect the control effect, and it is difficult to determine appropriate controller parameters.

[0006] (3) In actual production, due to the deviation in the manufacture of the stopper and the water nozzle, as well as uncontrollable factors such as the erosion and consumption of refractory materials, the difficulty of production control is increased. SUMMARY

[0007] The object of the present application is to provide a method for controlling the liquid level height of a thin strip continuous casting bath, so as to at least partially solve the problems existing in the prior art. The method for controlling the liquid level height of the thin strip continuous casting bath provided by the present application constructs a fuzzy controller, wherein the inputs of the fuzzy controller are the deviation of the liquid level height of the thin strip continuous casting bath and the change rate of the deviation of the liquid level height of the thin strip continuous casting bath. After being fuzzified, fuzzy reasoning and clarified, the method of the present application outputs a control signal to drive an actuator to act, so as to achieve the purpose of accurately adjusting the liquid level height of the bath according to requirements.

[0008] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0009] According to an aspect of the present application, a method for controlling the liquid level height of a thin strip continuous casting bath is provided, and the method comprises the following steps:

[0010] (1) Start the twin-roll thin strip continuous casting machine, control the initial linear velocity v of the cooling roll, control the target liquid level height h0, and control the inlet flow rate of the molten pool to Q;

[0011] (2) The original molten pool level height is continuously measured by the molten pool level height sensor, and the molten pool level height h is obtained after filtering;

[0012] (3) Calculate the deviation e=h0-h and the deviation change rate ec=de / dt. Multiply the deviation e and the deviation change rate ec by constants Ke and Kec respectively, so that the values ​​of e and ec are transformed to the range of the universe of discourse, i.e. E=e·Ke, EC=ec·Kec.

[0013] (4) Blur E and EC respectively to obtain fuzzy quantities E' and EC';

[0014] (5) Set fuzzy rules, and perform fuzzy inference operations on fuzzy quantities E' and EC' according to the fuzzy rules to obtain fuzzy quantity U';

[0015] (6) Defuzzify the fuzzy quantity U' to obtain the sharp value u within the output domain of the fuzzy controller;

[0016] (7) Multiply the clear value u by the constant Ku to obtain the input signal U=u·Ku of the actuator. The actuator makes corresponding actions based on the signal, thereby adjusting the liquid level height of the molten pool.

[0017] (8) Repeat the above steps to maintain the liquid level at the target value until production ends.

[0018] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, in step (1): the initial linear velocity of the cooling roller is controlled to be v = 0.1~1.5 m / s; the target liquid level height is controlled to be h0 = 10~300 mm; and the molten metal flow rate at the inlet of the molten pool is Q = 0~0.45 m³ / s. 3 / s.

[0019] According to the method for controlling the liquid level height of the molten pool in continuous strip casting of the present invention, preferably, in step (2), the filtering method is arithmetic mean filtering.

[0020] According to the method for controlling the molten pool level height in thin strip continuous casting of the present invention, preferably, in the arithmetic mean filtering, the original molten pool level height is continuously measured n times by a molten pool level height sensor, and the values ​​of the n measurements are arithmetically averaged. The arithmetic mean is the molten pool level height h obtained after filtering.

[0021] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, the measurement sampling frequency of the molten pool liquid level height sensor is controlled to be P=1~100Hz, and the number of measurements is controlled to be n=1~100.

[0022] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, the physical domain of the deviation e is [a,b], the physical domain of the deviation change rate ec is [c,d], and the physical domain of the clear value u is [e,f], where: a=-200~-5, b=5~200, c=-100~-5, d=-100~-5, e=-100~0, f=0~100.

[0023] In the method for controlling the molten pool level height in thin strip continuous casting according to the present invention, preferably, the fuzzy universes of discourse of fuzzy quantities E', EC', and U' are represented as X, Y, and Z, respectively, and the fuzzy universes of discourse X, Y, and Z are all {NB, NM, NS, Z, PS, PM, PB}, wherein:

[0024] NB, NM, NS, Z, PS, PM, PB are 7 fuzzy subsets, where NB = -PB, NM = -PM, NS = -PS, and NB... <NM<NS<Z<PS<PM<PB。

[0025] In the method for controlling the liquid level height of the molten pool in thin strip continuous casting according to the present invention, preferably, the fuzzy numbers corresponding to the fuzzy universes X and Y are {-3, -2, -1, 0, 1, 2, 3}; and the fuzzy number corresponding to the fuzzy universe Z has a value range of -30 to 30.

[0026] In the method for controlling the liquid level height of the molten pool in continuous strip casting according to the present invention, preferably, the constant ke = -10~10, the quantization factor kec = -10~10, and the constant kU = -10~10.

[0027] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, the method for clarifying the fuzzy amount U' is to calculate the fuzzy amount using the area centroid method.

[0028] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, the fuzzy rule is described in natural language as follows: if E' is X(i) and EC' is Y(j), then U' is Z(X(i), Y(j)), where i and j take values ​​ranging from 1 to 7.

[0029] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, the controller of the molten pool liquid level height control system is implemented by a programmable logic controller (PLC).

[0030] According to the method for controlling the liquid level height of the molten pool in thin strip continuous casting of the present invention, preferably, the controller of the molten pool liquid level height control system is implemented by a microcontroller.

[0031] According to the method for controlling the liquid level height of the molten pool in strip continuous casting of the present invention, preferably, the actuator of the liquid level height control system is configured as a motor-driven stopper rod and a cooling roller.

[0032] In the method for controlling the liquid level height of the molten pool in continuous strip casting according to the present invention, preferably, the membership functions for fuzzification and defuzzification are triangles and trapezoids.

[0033] According to the method for controlling the molten pool level height in thin strip continuous casting of the present invention, preferably, the fuzzy rule must satisfy at least one of the following rules 1 to 9:

[0034] Principle 1: When E' is PB and EC' is NB, U' is Z(PB, NB). When E' is NB and EC' is PB, U' is Z(NB, PB). Z(PB, NB) and Z(NB, PB) satisfy the relationship: |Z(PB, NB)|≤|Z(NB, PB)|.

[0035] Principle 2: When E' is PM and EC' is NB, U' is Z(PM, NB). When E' is NM and EC' is PB, U' is Z(NM, PB). Z(PM, NB) and Z(NM, PB) satisfy the relationship: |Z(PM, NB)|≤|Z(NM, PB)|.

[0036] Principle 3: When E' is PS and EC' is NB, U' is Z(PS, NB). When E' is NS and EC' is PB, U' is Z(NB, PB). Z(PS, NB) and Z(NB, PB) satisfy the relationship: |Z(PS, NB)|≤|Z(NB, PB)|.

[0037] Principle 4: When E' is PB and EC' is NM, U' is Z(PB, NM). When E' is NB and EC' is PM, U' is Z(NB, PM). Z(PB, NM) and Z(NB, PM) satisfy the relationship: |Z(PB, NM)|≤|Z(NB, PM)|.

[0038] Principle 5: When E' is PM and EC' is NM, U' is Z(PM, NM). When E' is NM and EC' is PM, U' is Z(NM, PM). Z(PM, NM) and Z(NM, PM) satisfy the relationship: |Z(PM, NM)|≤|Z(NM, PM)|.

[0039] Principle 6: When E' is PS and EC' is NM, U' is Z(PS, NM). When E' is NS and EC' is PM, U' is Z(PS, NM). Z(PS, NM) and Z(NS, PM) satisfy the relationship: |Z(PS, NM)|≤|Z(NS, PM)|.

[0040] Principle 7: When E' is PB and EC' is NS, U' is Z(PB, NS). When E' is NB and EC' is PS, U' is Z(NB, PS). Z(PB, NS) and Z(NB, PS) satisfy the relationship: |Z(PB, NS)|≤|Z(NB, PS)|.

[0041] Principle 8: When E' is PM and EC' is NS, U' is Z(PM, NS). When E' is NM and EC' is PS, U' is Z(NM, PS). Z(PM, NS) and Z(NM, PS) satisfy the relationship: |Z(PM, NS)|≤|Z(NM, PS)|.

[0042] Principle 9: When E' is PS and EC' is NS, U' is Z(PS, NS), and when E' is NS and EC' is PS, U' is Z(NS, PS). Z(PS, NS) and Z(NS, PS) satisfy the relation: |Z(PS, NS)|≤|Z(NS, PS)|.

[0043] Beneficial technical effects

[0044] Compared with the prior art, the technical concept and corresponding technical solution of the present invention can achieve at least the following beneficial technical effects:

[0045] The method for controlling the molten pool level height in continuous strip casting provided by this invention can achieve stable control of the molten pool level height during twin-roll continuous strip casting.

[0046] The method of the present invention is applicable to the control of the liquid level height of molten pools at different temperatures and with different metal materials.

[0047] The method of the present invention provides the determination principle of fuzzy rules through the controller, which can prevent overflow and reduce the difficulty of controller parameters.

[0048] The method of this invention uses fuzzy quantities instead of precise quantities for control, which is more robust and can minimize the impact of uncontrollable factors such as deviations in the manufacturing of stoppers and nozzles, as well as the erosion and consumption of refractory materials in actual production. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0050] Figure 1 This is a flowchart of a fuzzy control system for thin strip continuous casting according to an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of the thin strip continuous casting control system according to Embodiment 1 of the present invention.

[0052] The markings in the diagram are: 1. Tundish; 2. Molten metal; 3. Stopper rod; 4. Motor; 5. Programmable controller; 6. Computer; 7. Molten pool level sensor; 8. Cooling roller; 9. Metal sheet; 10. Molten pool.

[0053] Figure 3 This is a schematic diagram of the thin strip continuous casting control system according to Embodiment 2 of the present invention.

[0054] The markings in the diagram are: 1. Tundish; 2. Molten metal; 3. Stopper rod; 4. Motor; 5. Programmable controller; 6. Computer; 7. Molten pool level sensor; 8. Cooling roller; 9. Metal sheet; 10. Molten pool; 11. Motor. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0056] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0057] The following are embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention. All other embodiments that can be 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.

[0058] Example 1

[0059] Figure 2 The diagram below shows a thin strip continuous casting control system according to Embodiment 1 of the present invention. The inlet flow rate is controlled by controlling the position of the stopper rod, thereby adjusting the height of the molten pool.

[0060] In this embodiment, the fuzzy control algorithm is written into the programmable controller 5. Molten steel 2 is injected from the tundish 1 into the molten pool 10. The cooling roller 8 rotates at a constant linear speed of 0.6 m / s. The inlet flow rate of the molten pool 10 is controlled by the stopper rod 4. The molten pool level height is collected by the molten pool level height sensor 7 and transmitted to the programmable controller 5 via the computer 6. After filtering, the programmable controller 5 calculates the deviation e and the deviation change rate ec based on the collected level height and outputs a control signal to the motor 4. The motor 4 adjusts the position of the stopper rod 3 to control the input flow rate of the molten pool, so that the molten pool level height is maintained at 200 mm.

[0061] In this embodiment, the specific steps and parameters are as follows:

[0062] (1) Start the twin-roll thin strip continuous casting machine, the initial linear velocity of the cooling roll is v=0.6m / s, the target liquid level height is set to h0=200mm, and the initial inlet flow rate of the molten pool is Q=0.

[0063] (2) The original molten pool level height is continuously measured by the molten pool level height sensor, and the molten pool level height h is obtained after filtering.

[0064] (3) Calculate the deviation e=h0-h and the deviation change rate ec=de / dt. Multiply the deviation e and the deviation change rate ec by constants Ke and Kec respectively, so that the values ​​of e and ec are transformed to the range of the universe of discourse, i.e. E=e·Ke, EC=ec·Kec.

[0065] (4) Blur E and EC respectively to obtain fuzzy quantities E' and EC'.

[0066] (5) Set fuzzy rules, and perform fuzzy inference operations on fuzzy quantities E' and EC' according to the fuzzy rules to obtain fuzzy quantity U'.

[0067] (6) Defuzzify the fuzzy quantity U' to obtain the fuzzy controller output domain of the fuzzy value u.

[0068] (7) Multiply the clear value u by the constant Ku to obtain the input signal U=u·Ku of the actuator. Make corresponding changes according to the position of the stopper rod based on the signal, and then adjust the liquid level height of the molten pool.

[0069] (8) Repeat the above steps to keep the molten pool level constant at the target value until production ends.

[0070] In step (2), the original molten pool level height is continuously measured n times by the molten pool level height sensor 7. The values ​​of the n measurements are then arithmetically averaged, and this arithmetic average is the molten pool level height h obtained after filtering. The molten pool level height sensor has a measurement (sampling) frequency P = 50 Hz and a measurement number n = 10.

[0071] In this embodiment, the relevant parameters of the fuzzy control algorithm are as follows: the physical domain of the deviation e is [-150, 150], the physical domain of the deviation change rate ec is [-80, 80], and the physical domain of the clear value u is [-80, 80].

[0072] In this embodiment, the fuzzy domains of the fuzzy quantities E’, EC’ and U’ are respectively represented as X, Y, and Z. The fuzzy domains X, Y, and Z are all {NB, NM, NS, Z, PS, PM, PB}, where:

[0073] NB, NM, NS, Z, PS, PM, PB are 7 fuzzy subsets, NB = -PB, NM = -PM, NS = -PS, NB < NM < NS < Z < PS < PM < PB. The fuzzy numbers corresponding to the fuzzy domains X and Y are {-3, -2, -1, 0, 1, 2, 3}, and the value range of the fuzzy numbers corresponding to the fuzzy domain Z is -30 to 30.

[0074] In this embodiment, the membership functions of fuzzification and defuzzification are triangles and trapezoids. The constant ke = 3, the quantization factor kec = 3, and the constant kU = 5. The area centroid method is used to perform defuzzification calculation on the fuzzy quantity.

[0075] In this embodiment, its fuzzy rules satisfy Principle 1 and Principle 2:

[0076] Principle 1: When E’ is PB and EC’ is NB, U’ is Z(PB, NB). When E’ is NB and EC’ is PB, U’ is Z(NB, PB). Z(PB, NB) and Z(NB, PB) satisfy the relationship: |Z(PB, NB)| ≤ |Z(NB, PB)|.

[0077] Principle 2: When E’ is PM and EC’ is NB, U’ is Z(PM, NB). When E’ is NM and EC’ is PB, U’ is Z(NM, PB). Z(PM, NB) and Z(NM, PB) satisfy the relationship: |Z(PM, NB)| ≤ |Z(NM, PB)|.

[0078] Embodiment 2

[0079] Figure 3 As shown in the schematic diagram of the thin strip continuous casting control system in Embodiment 2 of the present invention, the outlet flow is controlled by controlling the rotational speed of the cooling roll to adjust the molten pool liquid level height.

[0080] In this embodiment, the fuzzy control algorithm is written into the programmable controller 5. Molten steel 2 is injected from the tundish 1 into the molten pool 10. The cooling roller 8 rotates at an initial linear velocity of 0.3 m / s. The molten pool level height is collected by the molten pool level height sensor 7 and transmitted to the programmable controller 5 via the computer 6. After filtering, the programmable controller 5 calculates the deviation e and the deviation change rate ec based on the collected level height and outputs a control signal to the motor 4. The motor 4 adjusts the rotation speed of the cooling roller 8 to control the output flow of the molten pool, so that the molten pool level height is maintained at 180 mm.

[0081] In this embodiment, the specific steps and parameters are as follows:

[0082] (1) Start the twin-roll thin strip continuous casting machine, with the initial linear velocity of the cooling rolls v=0.3m / s, the target liquid level height h0=180mm, and the inlet flow rate of the molten pool constant at Q=2000000mm. 3 / s.

[0083] (2) The original molten pool level height is continuously measured by the molten pool level height sensor, and the molten pool level height h is obtained after filtering.

[0084] (3) Calculate the deviation e=h0-h and the deviation change rate ec=de / dt. Multiply the deviation e and the deviation change rate ec by constants Ke and Kec respectively, so that the values ​​of e and ec are transformed to the range of the universe of discourse, i.e. E=e·Ke, EC=ec·Ke.

[0085] (4) Blur E and EC respectively to obtain fuzzy quantities E' and EC'.

[0086] (5) Set fuzzy rules, and perform fuzzy inference operations on fuzzy quantities E' and EC' according to the fuzzy rules to obtain fuzzy quantity U'.

[0087] (6) Defuzzify the fuzzy quantity U' to obtain the fuzzy controller output domain of the fuzzy value u.

[0088] (7) Multiply the clear value u by the constant Ku to obtain the input signal U=u·Ku of the actuator. Based on this signal, the speed of the cooling roller is changed accordingly, thereby adjusting the liquid level height of the molten pool.

[0089] (8) Repeat the above steps to keep the molten pool level constant at the target value until production ends.

[0090] In this embodiment, in step 2, the original molten pool level height is continuously measured n times by the molten pool level height sensor 7. The values ​​of the n measurements are then arithmetically averaged, and this arithmetic average is the molten pool level height h obtained after filtering. The molten pool level height sensor has a measurement (sampling) frequency P = 20Hz, and the number of measurements n = 5.

[0091] In this embodiment, the relevant parameters of the fuzzy control algorithm are as follows: the physical domain of the deviation e is [-130, 130], the physical domain of the deviation change rate ec is [-80, 80], and the physical domain of the clear value u is [-80, 80].

[0092] In this embodiment, the fuzzy domains of the fuzzy quantities E’, EC’ and U’ are respectively represented as X, Y, and Z. The fuzzy domains X, Y, and Z are all {NB, NM, NS, Z, PS, PM, PB}, where:

[0093] NB, NM, NS, Z, PS, PM, PB are 7 fuzzy subsets, NB = -PB, NM = -PM, NS = -PS, NB < NM < NS < Z < PS < PM < PB. The fuzzy numbers corresponding to the fuzzy domains X and Y are {-3, -2, -1, 0, 1, 2, 3}, and the value range of the fuzzy numbers corresponding to the fuzzy domain Z is -30 to 30.

[0094] In this embodiment, the membership functions of fuzzification and defuzzification are triangles and trapezoids. The constant ke = 4, the quantization factor kec = 4, and the constant kU = 6. The defuzzification calculation of the fuzzy quantity is performed by the area centroid method.

[0095] In this embodiment, the fuzzy rules satisfy Principle 6, Principle 7, and Principle 8:

[0096] Principle 6: When E’ is PS and EC’ is NM, U’ is Z(PS, NM). When E’ is NS and EC’ is PM, U’ is Z(PS, NM). Z(PS, NM) and Z(NS, PM) satisfy the relationship: |Z(PS, NM)| ≤ |Z(NS, PM)|.

[0097] Principle 7: When E’ is PB and EC’ is NS, U’ is Z(PB, NS). When E’ is NB and EC’ is PS, U’ is Z(NB, PS). Z(PB, NS) and Z(NB, PS) satisfy the relationship: |Z(PB, NS)| ≤ |Z(NB, PS)|.

[0098] Principle 8: When E’ is PM and EC’ is NS, U’ is Z(PM, NS). When E’ is NM and EC’ is PS, U’ is Z(NM, PS). Z(PM, NS) and Z(NM, PS) satisfy the relationship: |Z(PM, NS)| ≤ |Z(NM, PS)|.

[0099] The above are only the specific implementation manners of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for controlling the liquid level height of a molten pool in thin strip continuous casting, characterized in that, The method includes the following steps: (1) Start the twin-roll thin strip continuous casting machine, control the initial linear velocity v of the cooling roll, control the target liquid level height h0, and control the inlet flow rate of the molten pool to Q; (2) The original molten pool level height is continuously measured by the molten pool level height sensor, and the molten pool level height h is obtained after filtering; (3) Calculate the deviation e=h0-h and the deviation change rate ec=de / dt. Multiply the deviation e and the deviation change rate ec by constants Ke and Kec respectively, so that the values ​​of e and ec are transformed to the range of the universe of discourse, i.e. E=e·Ke, EC=ec·Kec. (4) Blur E and EC respectively to obtain fuzzy quantities E' and EC'; (5) Set fuzzy rules, and perform fuzzy inference operations on fuzzy quantities E' and EC' according to the fuzzy rules to obtain fuzzy quantity U'; (6) Defuzzify the fuzzy quantity U' to obtain the sharp value u within the output domain of the fuzzy controller; (7) Multiply the clear value u by the constant Ku to obtain the input signal U=u·Ku of the actuator. The actuator makes corresponding actions based on the signal, thereby adjusting the liquid level height of the molten pool. (8) Repeat the above steps to maintain the liquid level at the target value until production ends.

2. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 1, characterized in that: In step (1): The initial linear velocity of the cooling roller is controlled to be v = 0.1~1.5 m / s; The target liquid level height is controlled at h0 = 10~300 mm; The molten metal flow rate at the molten pool inlet is Q = 0~0.45m³. 3 / s.

3. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 1, characterized in that: In step (2), the filtering method is arithmetic mean filtering.

4. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 3, characterized in that: In the arithmetic mean filtering, the original molten pool level height is continuously measured n times by the molten pool level height sensor, and the values ​​of the n measurements are arithmetically averaged. This arithmetic mean is the molten pool level height h obtained after filtering.

5. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 4, characterized in that: The measurement sampling frequency of the molten pool level height sensor is controlled to be P=1~100Hz, and the number of measurements is controlled to be n=1~100.

6. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 1, characterized in that: The physical domain of the deviation e is [a, b], the physical domain of the rate of change of deviation ec is [c, d], and the physical domain of the sharpness value u is [e, f], where: a=-200~-5, b=5~200, c=-100~-5, d=-100~-5, e=-100~0, f=0~100.

7. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 1, characterized in that: The fuzzy universes of discourse for fuzzy quantities E', EC', and U' are denoted as X, Y, and Z, respectively. The fuzzy universes of discourse X, Y, and Z are all {NB, NM, NS, Z, PS, PM, PB}. in: NB, NM, NS, Z, PS, PM, PB are 7 fuzzy subsets, where NB = -PB, NM = -PM, NS = -PS, and NB... <NM<NS<Z<PS<PM<PB。 8. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 7, characterized in that: The fuzzy numbers corresponding to the fuzzy universes X and Y are {-3, -2, -1, 0, 1, 2, 3}; The range of fuzzy numbers corresponding to the fuzzy universe Z is -30 to 30.

9. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to claim 1, characterized in that: The constant ke = -10~10, the quantization factor kec = -10~10, and the constant kU = -10~10.

10. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to any one of claims 1 to 9, characterized in that: The method to clarify the fuzzy quantity U' is to use the area centroid method to calculate the fuzzy quantity.

11. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to any one of claims 1 to 9, characterized in that: Fuzzy rules can be described in natural language as follows: If E' is X(i) and EC' is Y(j), then U' is Z(X(i), Y(j)). The values ​​of i and j range from 1 to 7.

12. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to any one of claims 1 to 9, characterized in that: The controller of the molten pool level control system is implemented using a programmable logic controller (PLC).

13. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to any one of claims 1 to 9, characterized in that: The controller of the molten pool level control system is implemented using a microcontroller.

14. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to any one of claims 1 to 9, characterized in that: The actuators of the molten pool level control system are configured as motor-driven stoppers and cooling rollers.

15. The method for controlling the liquid level height of the molten pool in thin strip continuous casting according to any one of claims 1 to 9, characterized in that: The membership functions for blurring and sharpening are triangle and trapezoid.

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