A roughing and intermediate rolling anti-crown self-adaptive control method based on workpiece deflection detection

Abstract

The application discloses a roughing and intermediate rolling anti-head-curl self-adaptive control method based on workpiece deflection detection, which comprises the following steps: (1) a detection device is installed at the outlet side of the last stand of roughing or the first stand of intermediate rolling, and a deflection value θ of the head of the workpiece is obtained; (2) a required relative speed compensation amount ΔN_set of the upper roller and the lower roller is calculated according to the deflection value θ and process parameters, and the rotational speed of the upper roller and the lower roller is adjusted to compensate for the roller diameter difference; (3) the N_up_target and N_down_target set values are sent to the independent transmission frequency converters of the upper roller and the lower roller of the corresponding stand to adjust the rotational speed of the motor; (4) the deflection signal is continuously monitored, and the adjustment amplitude and rate of ΔN_set are limited; and (5) the stable relative speed compensation amount ΔN_set of the upper roller and the lower roller is recorded. Through real-time detection of the deflection of the workpiece, the speed difference between the upper roller and the lower roller is dynamically calculated and compensated, so that the uneven extension caused by the temperature difference and the wear difference is offset, and the workpiece is straightened and discharged.

Description

Technical Field

[0001] This invention relates to the field of bar and wire rod production technology, specifically to an adaptive control method for preventing warping in roughing and intermediate rolling based on workpiece deviation detection. Background Technology

[0002] In the roughing and intermediate rolling processes of bar and wire rods, "head curling" (i.e. the head of the rolled piece bends upward after exiting the mill) is a common problem that affects production stability and product quality. The root cause is that there is a temperature difference between the upper and lower surfaces of the rolled piece, as well as a speed difference or wear difference between the upper and lower rolls, which leads to uneven metal elongation on the upper and lower surfaces.

[0003] "Head tilting" is mainly caused by the coupling of two dynamic factors. First, because the cooling water in the rolling mill is usually sprayed from top to bottom, the temperature of the upper and lower surfaces of the workpiece is uneven, with the upper surface cooling more intensely, having a lower temperature, and greater resistance to deformation. Second, because the upper roll is in contact with the cooler, more deformation-resistant upper surface, its wear is usually more severe than that of the lower roll. As rolling progresses, the wear of the upper and lower rolls becomes asynchronous, and the difference in their diameters gradually increases, leading to a speed difference and further exacerbating uneven elongation. However, the existing technology for addressing the above problems has the following significant drawbacks: 1) The existing handling method relies on the operator's experience. After obvious head lifting occurs, the speed of the upper and lower rollers or the cooling water will be manually fine-tuned. However, the adjustment is lagging, the accuracy is poor, and it cannot cope with the continuous changes in wear. 2) The existing production line lacks a real-time, quantitative detection device for the posture (skewness) of the rolled parts after exiting the roll. Operators can only observe with their naked eyes and cannot obtain accurate skewness data, let alone establish a quantitative relationship between skewness and temperature difference and roll diameter difference. This makes the adjustment lack data support and is a "blind adjustment". 3) Even if it is realized that speed adjustment is needed, a fixed speed compensation value is usually set manually on the transmission system. This method is static and rigid and cannot adapt to changes such as material temperature fluctuations, real-time wear of the roller diameter, and different specifications of the die. The speed adjustment amount is not correlated in a closed loop with the detected deviation signal and the theoretical speed difference calculated based on the roller diameter. 4) Severe head lifting can cause the rolled piece to collide with the guide or roller table, resulting in steel pile-up accidents, generating scrap steel, and reducing the yield. At the same time, unstable bite and ejection can also impact the main drive system of the rolling mill, affecting the equipment life. Existing handling methods can only remedy the problem after it occurs, and cannot achieve early warning and adaptive prevention and control.

[0004] Therefore, how to solve the dynamic head-up problem caused by uneven temperature and roll wear differences in roughing and intermediate rolling has become an urgent problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an adaptive control method for preventing warping in roughing and intermediate rolling based on workpiece skew detection. By detecting the workpiece skew in real time, the method dynamically calculates and compensates for the speed difference between the upper and lower rolls, thereby offsetting the uneven elongation caused by temperature difference and wear difference, and realizing the straight ejection of the workpiece.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection, the innovation of the present invention lies in the following steps: (1) A detection device is installed at the exit side of the roughing end stand or the intermediate stand of the first stand, where head warping is likely to occur. The two probes of the detection device are arranged symmetrically above and below the center line of the rolling line, and the real-time detection data is transmitted to the PLC to obtain the deviation value θ of the head of the rolled piece. (2) Calculate the required relative speed compensation amount ΔN_set of the upper and lower rolls based on the above skewness value θ and process parameters, and adjust the rotation speed of the upper and lower rolls accordingly to compensate for the difference in roll diameter, so as to ensure that the exit linear velocity of the upper and lower surfaces of the rolled piece is consistent and the rolled piece is thrown out straight. (3) Send the N_up_target and N_down_target settings to the independent drive frequency converters of the upper and lower rollers of the corresponding frame. The frequency converters adopt speed closed-loop control to quickly and accurately adjust the motor speed. (4) Continuously monitor the skewness signal. If the skewness θ decreases and approaches zero, it indicates that the compensation is effective. At the same time, the adjustment range and rate of ΔN_set are subject to safety limits. (5) Record the stable relative speed compensation amount ΔN_set of the upper and lower rollers, and combine it with the steel throughput of the frame to back-calculate and update the estimated values ​​of upper roller wear amount W_up and lower roller wear amount W_down.

[0007] Preferably, in step (1) above, the two probes of the detection device are installed at a distance of 1 to 2 meters from the center line of the corresponding rolling line.

[0008] Preferably, in step (1) above, the detection device adopts a non-contact laser ranging or vision detection system, and measures the height of the upper and lower surfaces of the rolled piece relative to the baseline through the detection device, and transmits the detected data to the PLC. By calculating the difference between the two, the deviation value θ of the rolled piece head is obtained in real time, and after filtering, a stable and representative deviation value is extracted.

[0009] Preferably, an analog input module is added to the PLC to receive sensor signals.

[0010] Preferably, in step (2) above, the speed difference is calculated first, and then the skewness-speed compensation relationship model is established, specifically as follows: (2.1) Introduce the actual roller diameter, that is, the actual diameter of the upper roller D_act_up=D_nom-W_up, and the actual diameter of the lower roller D_act_down =D_nom-W_down; where W_up is the wear amount of the upper roller and W_down is the wear amount of the lower roller. The initial values ​​of the two can be obtained by estimation or offline measurement and updated by the system self-learning. (2.2) To achieve the same exit linear velocity V, the theoretical speeds of the upper roller and the lower roller should be respectively: N_up_theory = V / [ (D_act_up - h) π i]; N_down_theory = V / [ (D_act_down - h) π i]; Where N_up_theory is the theoretical speed of the upper roll; N_down_theory is the theoretical speed of the lower roll; V is the process set linear velocity; D_nom is the nominal diameter of the roll; h is the roll height; and i is the speed ratio of the reducer. (2.3) Establish the relationship between the skewness value θ and the required relative speed compensation amount ΔN_set of the upper and lower rollers, that is, the target speed of the upper roller N_up_target = N_up_theory + ΔN_set, and the target speed of the lower roller N_down_target = N_down_theory.

[0011] Preferably, in step (2.3) above, the initial relationship can be set based on theoretical derivation and process experience, i.e., ΔN_set = K_p θ+K_i ∫θ dt, where K_p is the proportionality coefficient and K_i is the integral coefficient.

[0012] Preferably, a positive value of ΔN_set indicates that the upper roller speed needs to be increased, and a negative value of ΔN_set indicates that the lower roller speed needs to be decreased.

[0013] Preferably, in step (5) above, when the temperature of the incoming material is detected to be fluctuating significantly by measuring the temperature at the outlet of the heating furnace or the inlet of the rack, a feedforward compensation amount based on the temperature difference can be introduced in advance and superimposed with the skewness feedback compensation to improve the response speed and achieve temperature fluctuation compensation.

[0014] The beneficial effects of this invention are: (1) The present invention detects the deviation of the rolled piece in real time, dynamically calculates and compensates for the speed difference between the upper and lower rolls, thereby offsetting the uneven elongation caused by temperature difference and wear difference, and realizing the straight ejection of the rolled piece; (2) This invention achieves real-time automatic correction of the tilting problem through online detection and automatic adjustment, which can suppress the tilting at the bud stage, significantly reduce the steel stacking and jamming accidents caused by it, improve the working rate and yield, and enhance production stability; (3) The present invention accurately quantifies the skewness through laser or visual detection and performs compensation calculation based on the skewness-velocity compensation relationship model, making the adjustment more scientific and precise and avoiding the blindness and over-adjustment of manual adjustment; (4) Through closed-loop feedback, the present invention can automatically adapt to the continuous changes in roll wear and the fluctuations in incoming material temperature, thereby achieving stable control throughout the entire production cycle. (5) The smooth ejection of the rolled piece by the present invention reduces the impact on the guide and roller table, and also makes the load on the upper and lower rollers more balanced, which helps to reduce the difference in roller wear caused by uneven wear and extend the service life of the entire set of roller rings. (6) The present invention requires minimal modification to existing rolling mills that already have independent transmission or differential speed adjustment functions, and has low investment costs, but the economic benefits of preventing accidents and improving yield are significant. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skew detection, according to the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below through specific embodiments.

[0018] This invention provides an adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skew detection, such as... Figure 1 As shown, it includes the following steps: (1) A detection device is installed at the exit side of the roughing end stand or the intermediate stand that is prone to head lifting. The two probes of the detection device are arranged symmetrically above and below the center line of the rolling line, and the real-time detection data is transmitted to the PLC to obtain the deviation value θ of the head of the rolled piece.

[0019] The two probes of the detection device of the present invention are installed at a distance of 1 to 2 meters from the center line of the corresponding rolling line. Since the rolled piece has been freed from the constraint of the roll at this location, its posture can truly reflect the difference in vertical extension.

[0020] The detection device of this invention adopts a non-contact laser ranging or vision inspection system. The detection device measures the height of the upper and lower surfaces of the rolled piece relative to the baseline and transmits the detected data to the PLC. By calculating the difference between the two, the deviation value θ of the rolled piece head is obtained in real time. After filtering, a stable and representative deviation value is extracted. In this invention, an analog input module is added to the PLC to receive sensor signals.

[0021] (2) Since the diameters of the upper and lower rolls are different due to wear, the required relative speed compensation amount ΔN_set of the upper and lower rolls is calculated based on the above-mentioned skewness value θ and process parameters. The rotation speed of the upper and lower rolls is adjusted accordingly to compensate for the difference in roll diameter, ensuring that the exit linear velocity of the upper and lower surfaces of the rolled piece is consistent, so that the rolled piece is thrown out straight.

[0022] In the above steps, the speed difference is calculated first, and then the skewness-speed compensation relationship model is established, specifically as follows: (2.1) Introduce the actual roller diameter, that is, the actual diameter of the upper roller D_act_up = D_nom-W_up, and the actual diameter of the lower roller D_act_down = D_nom-W_down; where W_up is the wear amount of the upper roller and W_down is the wear amount of the lower roller. The initial values ​​of the two can be obtained by estimation or offline measurement and updated by the system self-learning. (2.2) To achieve the same exit linear velocity V, the theoretical speeds of the upper roller and the lower roller should be respectively: N_up_theory = V / [ (D_act_up - h) π i]; N_down_theory = V / [ (D_act_down - h) π i]; Where N_up_theory is the theoretical speed of the upper roll; N_down_theory is the theoretical speed of the lower roll; V is the process set linear velocity; D_nom is the nominal diameter of the roll; h is the roll height; and i is the speed ratio of the reducer. (2.3) Establish the relationship between the skewness value θ and the required relative speed compensation amount ΔN_set of the upper and lower rollers, that is, the target speed of the upper roller N_up_target = N_up_theory + ΔN_set, and the target speed of the lower roller N_down_target = N_down_theory.

[0023] The initial relationship of this invention can be set based on theoretical derivation and process experience, i.e., ΔN_set = K_p θ+K_i ∫θdt, where K_p is the proportionality coefficient and K_i is the integral coefficient.

[0024] In this invention, a positive value of ΔN_set indicates that the upper roller speed needs to be increased, and a negative value of ΔN_set indicates that the lower roller speed needs to be decreased.

[0025] (3) Send the N_up_target and N_down_target settings to the independent drive frequency converters of the upper and lower rollers of the corresponding frame. The frequency converters adopt speed closed-loop control to quickly and accurately adjust the motor speed.

[0026] (4) Continuously monitor the skewness signal. If the skewness θ decreases and approaches zero, it indicates that the compensation is effective. At the same time, the adjustment range and rate of ΔN_set are safely limited to prevent over-adjustment from causing the rolled piece to "clamp" or the transmission system to overload.

[0027] (5) Record the stable relative speed compensation amount ΔN_set of the upper and lower rollers, and combine it with the steel throughput of the frame to back-calculate and update the estimated values ​​of upper roller wear amount W_up and lower roller wear amount W_down, so as to make the theoretical speed calculation more accurate, reduce the dependence on skewness feedback, and achieve more forward-looking compensation.

[0028] When the temperature of the incoming material is detected to fluctuate significantly by measuring the temperature at the outlet of the heating furnace or the inlet of the rack, this invention can introduce a feedforward compensation amount based on the temperature difference in advance, which is superimposed on the skewness feedback compensation to improve the response speed and achieve temperature fluctuation compensation.

[0029] Example Rolling specifications: Φ60mm round billet; process setting linear speed V=1.2m / s.

[0030] This invention provides an adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skew detection, such as... Figure 1 As shown, it includes the following steps: (1) A detection device is installed at the exit side of the roughing end stand or the intermediate stand that is prone to head lifting. The two probes of the detection device are arranged symmetrically above and below the center line of the rolling line and are installed at a distance of 1.5 meters from the corresponding center line of the rolling line. The real-time detection data is transmitted to the PLC to obtain the deviation value θ of the head of the rolled piece.

[0031] (2) Initial parameter setting The nominal diameter of the roll is D_nom = 580mm, the roll height is h = 60mm, and the speed ratio of the reducer is i = 1.

[0032] Initial wear estimates: upper roller wear W_up = 0.5 mm, lower roller wear W_down = 0.3 mm (based on data from the previous rolling period).

[0033] Theoretical rotational speed is calculated as follows: Theoretical rotational speed of the upper roller N_up_theory ≈ 1.2 / ((0.580-0.060)) π 1) ≈0.735 r / s (44.1 rpm); The theoretical rotational speed of the lower roller, N_down_theory, ≈ 1.2 / ((0.580-0.060-0.002) π 1) ≈ 0.738 r / s (44.3 rpm); Control parameters: proportional coefficient K_p = 0.05 (rpm / degree), integral coefficient K_i = 0.01 (rpm / degree·s).

[0034] (3) Operation process (one adjustment cycle) Initial state: Due to cooling of the upper surface and wear of the upper roll, the rolled piece warps upward, and θ = +2.5° (upward is positive) is detected.

[0035] The system calculates the relative speed compensation of the upper and lower rollers as follows: ΔN_set = 0.052.5 + 0.01∫2.5dt ≈ 0.125 + 0.025 = 0.15 rpm.

[0036] Adjustments are executed: upper roller target speed N_up_target = 44.1 + 0.15 = 44.25 rpm; lower roller target speed N_down_target = 44.3 rpm (remains unchanged); system commands are sent to the frequency converter.

[0037] Feedback: After about 3 seconds (at the head of the next steel piece), the deflection angle θ was detected to have decreased to +0.8°; the system continued to fine-tune until θ stabilized within ±0.3°, and the rolled piece was thrown out straight.

[0038] (4) Self-learning process After rolling 2,000 tons in this batch, the system statistics showed that, in order to maintain flatness, the average upper roller speed needed was about 0.2 rpm higher than the theoretical value.

[0039] Based on this, the system reverse-engineers and adjusts the upper roller wear estimate W_up from 0.5mm to 0.7mm, and updates the theoretical speed calculation model accordingly. At the start of the next batch, the initial theoretical speed difference is closer to the actual value, requiring less skewness feedback compensation and resulting in a faster system response.

[0040] The beneficial effects of this invention are: (1) The present invention detects the deviation of the rolled piece in real time, dynamically calculates and compensates for the speed difference between the upper and lower rolls, thereby offsetting the uneven elongation caused by temperature difference and wear difference, and realizing the straight ejection of the rolled piece; (2) This invention achieves real-time automatic correction of the tilting problem through online detection and automatic adjustment, which can suppress the tilting at the bud stage, significantly reduce the steel stacking and jamming accidents caused by it, improve the working rate and yield, and enhance production stability; (3) The present invention accurately quantifies the skewness through laser or visual detection and performs compensation calculation based on the skewness-velocity compensation relationship model, making the adjustment more scientific and precise and avoiding the blindness and over-adjustment of manual adjustment; (4) Through closed-loop feedback, the present invention can automatically adapt to the continuous changes in roll wear and the fluctuations in incoming material temperature, thereby achieving stable control throughout the entire production cycle. (5) The smooth ejection of the rolled piece by the present invention reduces the impact on the guide and roller table, and also makes the load on the upper and lower rollers more balanced, which helps to reduce the difference in roller wear caused by uneven wear and extend the service life of the entire set of roller rings. (6) The present invention requires minimal modification to existing rolling mills that already have independent transmission or differential speed adjustment functions, and has low investment costs, but the economic benefits of preventing accidents and improving yield are significant.

[0041] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, all modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope of the present invention. The technical content for which protection is sought in the present invention has been fully described in the technical requirements.

Claims

1. An adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection, characterized in that... Includes the following steps: (1) A detection device is installed at the exit side of the roughing end stand or the intermediate stand of the first stand, where head warping is likely to occur. The two probes of the detection device are arranged symmetrically above and below the center line of the rolling line, and the real-time detection data is transmitted to the PLC to obtain the deviation value θ of the head of the rolled piece. (2) Calculate the required relative speed compensation amount ΔN_set of the upper and lower rolls based on the above skewness value θ and process parameters, and adjust the rotation speed of the upper and lower rolls accordingly to compensate for the difference in roll diameter, so as to ensure that the exit linear velocity of the upper and lower surfaces of the rolled piece is consistent and the rolled piece is thrown out straight. (3) Send the N_up_target and N_down_target settings to the independent drive frequency converters of the upper and lower rollers of the corresponding frame. The frequency converters adopt speed closed-loop control to quickly and accurately adjust the motor speed. (4) Continuously monitor the skewness signal. If the skewness θ decreases and approaches zero, it indicates that the compensation is effective. At the same time, the adjustment range and rate of ΔN_set are subject to safety limits. (5) Record the stable relative speed compensation amount ΔN_set of the upper and lower rollers, and combine it with the steel throughput of the frame to back-calculate and update the estimated values ​​of upper roller wear amount W_up and lower roller wear amount W_down.

2. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection, as described in claim 1, is characterized in that: In step (1) above, the two probes of the detection device are installed at a distance of 1 to 2 meters from the center line of the corresponding rolling line.

3. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection, as described in claim 2, is characterized in that: In step (1) above, the detection device adopts a non-contact laser ranging or vision detection system, and measures the height of the upper and lower surfaces of the rolled piece relative to the baseline through the detection device, and transmits the detected data to the PLC. By calculating the difference between the two, the deviation value θ of the rolled piece head is obtained in real time, and after filtering, a stable and representative deviation value is extracted.

4. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection according to claim 3, characterized in that: Add an analog input module to the PLC mentioned above to receive sensor signals.

5. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection according to claim 1, characterized in that: In step (2) above, the speed difference is calculated first, and then the skewness-speed compensation relationship model is established, specifically as follows: (2.1) Introduce the actual roller diameter, that is, the actual diameter of the upper roller D_act_up = D_nom - W_up, and the actual diameter of the lower roller D_act_down = D_nom - W_down; where W_up is the wear amount of the upper roller and W_down is the wear amount of the lower roller. The initial values ​​of the two can be obtained by estimation or offline measurement and updated by the system self-learning. (2.2) To achieve the same exit linear velocity V, the theoretical speeds of the upper roller and the lower roller should be respectively: N_up_theory = V / [ (D_act_up - h) π i ]; N_down_theory = V / [ (D_act_down - h) π i ]; Where N_up_theory is the theoretical speed of the upper roll; N_down_theory is the theoretical speed of the lower roll; V is the process set linear velocity; D_nom is the nominal diameter of the roll; h is the roll height; and i is the speed ratio of the reducer. (2.3) Establish the relationship between the skewness value θ and the required relative speed compensation amount ΔN_set of the upper and lower rollers, that is, the target speed of the upper roller N_up_target = N_up_theory + ΔN_set, and the target speed of the lower roller N_down_target = N_down_theory.

6. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection according to claim 5, characterized in that: In step (2.3) above, the initial relationship can be set based on theoretical derivation and process experience, i.e., ΔN_set = K_p θ+K_i ∫θ dt, where K_p is the proportionality coefficient and K_i is the integral coefficient.

7. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection according to claim 6, characterized in that: A positive value for ΔN_set indicates that the upper roller speed needs to be increased, while a negative value for ΔN_set indicates that the lower roller speed needs to be decreased.

8. The adaptive control method for preventing warping in roughing and intermediate rolling mills based on workpiece skewness detection according to claim 1, characterized in that: In step (5) above, when the temperature of the incoming material fluctuates significantly when the temperature is measured at the outlet of the heating furnace or the inlet of the rack, a feedforward compensation based on the temperature difference can be introduced in advance and superimposed with the skewness feedback compensation to improve the response speed and achieve temperature fluctuation compensation.

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