A precise control method for the control model of the thickened end of a drawing and reducing machine head based on online speed feedback

Abstract

This invention relates to a precise control method for the head and tail thickening end control model of a tension reduction mill based on online speed feedback, belonging to the field of hot rolling technology for steel pipes in the iron and steel metallurgical industry. This invention addresses the technical problem of insufficient accuracy and stability in the head and tail thickening end control model caused by traditional methods relying solely on a heat detection device as a signal trigger point, which is susceptible to interference from roller slippage, water mist and vapor generated by the high-pressure water descaling device, and signal loss. The invention proposes superimposing a heat detection device and a speed measuring device at the roller table at the tension reduction mill inlet, far from the high-pressure water descaling device, with both located on the same horizontal coordinate. The speed measuring device monitors the steel pipe speed in real time and calculates the travel distance and arrival time at stand 1. Combined with signal verification and double-layer protection from the heat detection device, the calculation results of the original head and tail thickening end control model are automatically compensated, precisely controlling the dynamic CEC (Central Elongation Capacity) reduction process at the head and tail of the steel pipe during the tension reduction process. This method effectively avoids roller slippage and environmental interference, improving the metal yield.

Description

Technical Field

[0001] This invention belongs to the field of hot rolling process of steel pipe in the iron and steel metallurgical industry, and relates to a precise control method based on online speed measurement feedback for the Crop End Control (CEC) model of the tension reduction mill. Background Technology

[0002] The head and tail thickening end control model technology of the tension reduction mill, also known as the head and tail thickening end control technology of steel pipe, is a technology that uses a numerical control calculation model to dynamically adjust the speed of the roll motors of each stand of the tension reduction mill during the final rolling process of steel pipe. This establishes additional inter-stand tension and adds an additional wall-thickness reduction deformation to the head and tail ends of the steel pipe during rolling. This suppresses the thickening phenomenon at the head and tail ends of the steel pipe caused by uneven deformation, and ultimately achieves the goal of reducing cutting losses and increasing yield.

[0003] The control strategy of the head and tail thickening end control model mainly includes time control strategy and speed control strategy. The main calculation logic of the whole model is as follows: a detector is set at the inlet of the tension reduction mill as the signal trigger start point. Based on this, according to known data such as the head and tail thickening length of the steel pipe, the parameters of the tension reduction mill equipment, and the specifications of the steel pipe before and after rolling, the real-time position of the steel pipe, the start time and end time of the head and tail thickening end control model of each stand, and the speed change amplitude are automatically calculated.

[0004] The traditional control method for the thickening ends at both ends involves placing a thermal detection device at the entrance roller conveyor of the tension reduction mill as the signal triggering starting point. However, this method has certain drawbacks: the thermal detection device can only determine the start time, but slippage is inevitable during the conveying process of the steel pipe on the roller conveyor, making it difficult for the model to accurately control the real-time position of the steel pipe, thus ultimately affecting the accuracy of the control model for the thickening ends at both ends. In particular, since a high-pressure water descaling device is usually installed near the entrance of the tension reduction mill, the water vapor and mist generated during operation will affect the detection effect of the thermal detection device, thereby affecting the stability of the control model for the thickening ends at both ends. If the thermal detection device is moved away from this area, the negative impact of roller conveyor slippage on the accuracy of model control will be further aggravated.

[0005] In the traditional head and tail thickening end control model, a thermal detection device is installed at the inlet of the tensioning mill as the signal triggering starting point. To minimize the negative impact of roller slippage, the thermal detection device is placed as close as possible to the tensioning mill, typically within 1 meter of the center line of the No. 1 frame. The fatal problem with this approach is that if the thermal detection device loses its signal due to equipment failure or environmental interference such as water mist or vapor around the high-pressure water descaling device, the entire head and tail thickening end control model will fail.

[0006] Therefore, the existing technical problem is that the traditional signal triggering method relying solely on the thermal detection device cannot effectively overcome problems such as roller slippage, water mist and water vapor interference generated by the high-pressure water descaling device, and signal loss caused by equipment failure. It is difficult to accurately determine the real-time position, stroke, and arrival time of the steel pipe head and tail, resulting in insufficient accuracy and stability of the head and tail thickening end control model, which affects the further improvement of metal yield. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a precise control method for the head and tail thickening end control model of a tension reduction machine based on online speed measurement feedback.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A precise control method for the head and tail thickening end control model of a tension reduction mill based on online velocity measurement feedback includes the following steps: A set of thermal detection device and a set of speed measuring device are superimposed at the roller table at the inlet of the tension reduction machine, away from the high-pressure water descaling device, and the thermal detection device and the speed measuring device are located at the same horizontal coordinate position. The speed measuring device is used to monitor the real-time speed of the steel pipe and calculate the travel distance, position, and time of the head and tail of the steel pipe on the roller conveyor to reach the No. 1 frame of the tension reduction machine. The monitoring results of the speed measuring device are verified by the signal from the thermal detection device to prevent misjudgment. The calculation results of the original CEC model are automatically compensated based on the time of the judgment, and the dynamic pressing process of CEC at the beginning and end of the steel pipe tension reduction process is controlled accordingly.

[0009] Furthermore, the speed measuring device calculates the travel distance and time of the steel pipe in the following manner: Let each scan cycle be The average reading of the speed measuring device in each scanning cycle is The distance the steel pipe travels on the roller conveyor within a certain time is... The total time taken for this distance is ,in For the scan cycle, The average reading of the speed measuring device within each scanning cycle.

[0010] Furthermore, for the head of the steel pipe, the distance between the speed measuring device and the No. 1 frame of the tension reduction machine on the entrance roller conveyor is L1. When the head of the steel pipe reaches the speed measuring device, the speed measuring device measures the length of the steel pipe that has passed. When the measured length of the steel pipe is L1, it is considered that the head of the steel pipe has reached the No. 1 frame of the tension reduction machine. At this time, the CEC control of the No. 1 frame is triggered, where L1 is the distance between the speed measuring device and the No. 1 frame of the tension reduction machine.

[0011] Furthermore, a check point is set at the entrance roller conveyor of the tension reduction machine at a distance of L0 from the No. 1 frame of the tension reduction machine, where L0 is a known point less than or equal to 1m; The timing begins when the steel pipe head reaches the speed measuring device. The actual time when the steel pipe head reaches the L0 point is defined as T1, and the average speed of the steel pipe head at the L0 point is V0. Then, the accurate time T1 when the steel pipe head actually reaches the No. 1 frame of the tension reduction machine is equal to L0 divided by V0. The time compensation value is obtained by comparing the T1 with the theoretically calculated t1 of the original CEC model. and the The values ​​are automatically compensated to the start, arrival, and end times of the CEC head of each frame, where L0 is the distance between the verification point and frame 1 of the tensioning machine, V0 is the average velocity value of the steel pipe head just reaching the L0 point, and t1 is the theoretical calculation data of the original CEC model.

[0012] Furthermore, for the tail of the steel pipe, the distance between the speed measuring device and the No. 1 frame of the tension reducing machine is L1. The loss of signals from the thermal detection device and the speed measuring device is used as the signal for the tail to pass through the fixed point. At this time, the time for the thickened section of the tail to reach the No. 1 frame is L1 divided by V0', where V0' is the measured inlet speed. Time error is , where V is the theoretically set inlet velocity; The The value is automatically compensated to the start time, arrival time and end time of the CEC tail of each rack, where L1 is the distance between the speed measuring device and the No. 1 rack of the tension reduction machine, V0' is the measured inlet speed and V is the theoretical set inlet speed.

[0013] Furthermore, if the speed measuring device loses its signal but the thermal detection device still has a signal, it is assumed that the steel pipe is still passing through; if the speed measuring device's signal is intermittent, the speed measuring device continues to integrate according to the speed at the moment the signal is lost, ensuring the accuracy of the measured length.

[0014] Furthermore, when the speed measuring device fails to work, the thermal detection device triggers the CEC to work by adding a fixed delay to its signal.

[0015] The beneficial effects of this invention are as follows: (1) This invention proposes a precise control method for the head and tail thickening end control model of the tension reduction mill based on online speed feedback. A heat detection device and a speed measuring device are superimposed at the roller table at the inlet of the tension reduction mill, which is far away from the high-pressure water descaling device. Through the superposition of the two detection elements, the real-time position, stroke and arrival time of the steel pipe head and tail at the inlet of the tension reduction mill can be accurately determined. The calculation results of the original head and tail thickening end control model are automatically compensated, thereby significantly improving the control accuracy of the head and tail thickening end control model.

[0016] (2) The present invention monitors the speed of the steel pipe in real time by measuring the speed device and calculates the travel distance by integration, which effectively avoids the negative impact of roller slippage on the steel pipe position judgment in the traditional method, and enables the model to accurately control the actual movement state of the steel pipe.

[0017] (3) The present invention arranges the thermal detection device and the speed measuring device at the same horizontal coordinate position and can be far away from the high-pressure water descaling device at the inlet of the tension reducer. This can effectively avoid environmental interference such as water mist, water vapor and iron oxide scale generated when the high-pressure water descaling device is working, and improve the reliability and stability of the detection signal.

[0018] (4) In this invention, the thermal detection device and the speed measuring device form a mutual verification and double-layer insurance mechanism. When the speed measuring device loses a signal or is intermittent, the thermal detection device can verify in time and ensure the correctness of the judgment, avoiding the control model of the head and tail thickening end being disordered due to a single signal failure. When the speed measuring device cannot work normally, the thermal detection device can be used as an emergency measure to continue to trigger the control, ensuring the continuity and stability of production.

[0019] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of the traditional CEC control and detection signal layout; Figure 2 This is a schematic diagram of the CEC control and detection signal arrangement for the tension reduction machine. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0022] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0023] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0024] Figure 1 This is a schematic diagram of the control and detection signal arrangement for a traditional head and tail thickening end control model. (See diagram below.) Figure 1 As shown, in the traditional scheme, only one thermal detection device is installed at the entrance roller conveyor of the tensioning mill, which serves as the signal triggering starting point. To minimize the negative impact of roller slippage, the thermal detection device is placed as close as possible to the tensioning mill, typically within 1 meter of the center line of the No. 1 frame. While this arrangement can reduce slippage errors to some extent, the tensioning mill entrance is usually equipped with a high-pressure water descaling device. This device generates a large amount of water vapor, mist, and iron oxide scale during operation, which severely interferes with the detection effect of the thermal detection device. If the thermal detection device loses its signal due to equipment failure or environmental interference, the entire head and tail thickening end control model will completely fail, making effective control of the steel pipe's head and tail thickening ends impossible.

[0025] Figure 2 This is a schematic diagram showing the arrangement of control and detection signals for the control model at the head and tail thickening ends of the tension reduction machine according to the present invention. Figure 2 As shown, this invention superimposes a thermal detection device and a speed measuring device at the roller conveyor at the inlet of the tension reduction mill, away from the high-pressure water descaling device, with the thermal detection device and the speed measuring device located at the same horizontal coordinate position. Through this superimposed arrangement, the speed measuring device can monitor the steel pipe speed in real time and accurately calculate the travel distance, position, and arrival time of the steel pipe's head and tail at frame 1 of the tension reduction mill. The thermal detection device serves as signal verification and double-layer protection, thereby achieving automatic compensation of the calculation results of the original head and tail thickening end control model.

[0026] Example 1 This embodiment specifically illustrates the workflow of achieving precise triggering and compensation control at the head and tail of steel pipes by superimposing a thermal detection device and a speed measuring device under normal production conditions.

[0027] First, a thermal detection device and a speed measuring device are installed at the roller conveyor at the inlet of the tensioning mill, away from the high-pressure water descaling device, and both are located at the same horizontal coordinate position. After production begins, when the steel pipe head reaches the speed measuring device, the speed measuring device starts real-time speed monitoring. The speed measuring device operates according to each scanning cycle... The average reading within each scan cycle is The integral is calculated in the manner described above, where For the scan cycle, The average reading of the speed measuring device within each scanning cycle. The distance the steel pipe travels on the roller conveyor within a certain time is... The total time taken for this distance is .

[0028] For the steel pipe head, the distance between the speed measuring device and the No. 1 frame of the tension reduction machine on the inlet roller conveyor is set to L1. When the steel pipe head reaches the speed measuring device, the device continuously measures the length of the steel pipe it passes. Once the measured length equals L1, it is determined that the steel pipe head has reached the No. 1 frame of the tension reduction machine, and the head and tail thickening end control model of the No. 1 frame is immediately triggered. Simultaneously, a check point is set at the inlet roller conveyor of the tension reduction machine at a distance L0 from the No. 1 frame, where L0 is a known point less than or equal to 1 meter. Taking the arrival of the steel pipe head at the speed measuring device as the timing start point, the actual time T1 for the steel pipe head to reach point L0 is recorded. At the same time, the average speed value V0 at which the steel pipe head just reaches point L0 is measured. Therefore, the accurate time T1 for the actual arrival of the steel pipe head at the No. 1 frame of the tension reduction machine is equal to L0 divided by V0. This actual time T1 is compared with the theoretically calculated data t1 from the original head and tail thickening end control model to obtain the time compensation value. Where t1 is the theoretical calculation data of the original head and tail thickening end control model. Then, this... The value is automatically compensated to the start, arrival, and end times of the head of the control model at the thickened ends of each rack, achieving precise adjustment of the head control.

[0029] For the tail section of the steel pipe, since the speed at the tail section is almost constant, the simultaneous loss of signals from both the thermal detection device and the speed measuring device is taken as the signal that the tail section has passed the fixed point. At this time, the time for the thickened section at the tail section to reach frame 1 is L1 divided by V0', where V0' is the measured inlet speed. Time error. Where V is the theoretically set inlet velocity. The value is automatically compensated to the start, arrival, and end times of the tail control model at the head and tail of each rack, achieving precise adjustment of the tail control.

[0030] Finally, based on the compensated time parameters, the head and tail thickening end control model drives the speed adjustment of the rolling mill motors of each frame of the tension reduction mill to establish additional inter-frame tension and apply additional wall reduction deformation to the head and tail ends of the steel pipe, thereby effectively suppressing the phenomenon of thickening at the head and tail ends.

[0031] Example 2 This embodiment specifically illustrates the workflow of mutual verification and emergency handling between the thermal detection device and the speed measuring device under abnormal operating conditions, while further supporting the normal workflow in Embodiment 1.

[0032] During production, when the speed measuring device loses a signal, the thermal detection device continues to output a signal. At this time, the system assumes the steel pipe is still passing through and will not mistakenly determine that the pipe has completely passed, thus avoiding control model malfunctions at the beginning and end thickening ends or excessive thinning of the steel pipe due to a single signal failure. When the speed measuring device signal is intermittent, the speed measuring device immediately continues to perform integral calculations based on the speed at the moment the signal was lost, ensuring the continuity and accuracy of the steel pipe's travel distance and position measurement. Meanwhile, the thermal detection device continuously provides verification signals to ensure the reliability of the overall judgment.

[0033] When the speed measuring device becomes completely inoperable due to a malfunction, the system automatically switches to the emergency mode of the thermal detection device: based on the signal detected by the thermal detection device, a fixed delay is added before triggering the control model of the head and tail thickening ends to ensure production continuity. At this time, the thermal detection device also serves as a verification and safety device, ensuring that the control model of the head and tail thickening ends can still operate normally even if the speed measuring device fails.

[0034] Through the detailed description of the two embodiments above, the present invention can achieve high-precision position judgment and compensation control under normal conditions in actual production, and can also maintain stable system operation under abnormal signal conditions.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A precise control method for the head and tail thickening end control model of a tension reduction machine based on online speed measurement feedback, characterized in that: Includes the following steps: A set of thermal detection device and a set of speed measuring device are superimposed at the roller table at the inlet of the tension reduction machine, away from the high-pressure water descaling device, and the thermal detection device and the speed measuring device are located at the same horizontal coordinate position. The speed measuring device is used to monitor the real-time speed of the steel pipe and calculate the travel distance, position, and time of the head and tail of the steel pipe on the roller conveyor to reach the No. 1 frame of the tension reduction machine. The monitoring results of the speed measuring device are verified by the signal from the thermal detection device to prevent misjudgment. The calculation results of the original CEC model are automatically compensated based on the time of the judgment, and the dynamic pressing process of CEC at the beginning and end of the steel pipe tension reduction process is controlled accordingly.

2. The precise control method for the head and tail thickening end control model of the tension reduction machine based on online speed measurement feedback as described in claim 1, characterized in that: The speed measuring device calculates the travel distance and time of the steel pipe in the following manner: Let each scan cycle be The average reading of the speed measuring device in each scanning cycle is The distance the steel pipe travels on the roller conveyor within a certain time is... The total time taken for this distance is ,in For the scan cycle, The average reading of the speed measuring device within each scanning cycle.

3. The precise control method for the head and tail thickening end control model of the tension reduction machine based on online speed measurement feedback as described in claim 1, characterized in that: For the head of the steel pipe, the distance between the speed measuring device and the No. 1 frame of the tension reduction machine on the entrance roller conveyor is L1. When the head of the steel pipe reaches the speed measuring device, the speed measuring device measures the length of the steel pipe that has passed. When the measured length of the steel pipe is L1, it is considered that the head of the steel pipe has reached the No. 1 frame of the tension reduction machine. At this time, the CEC control of the No. 1 frame is triggered, where L1 is the distance between the speed measuring device and the No. 1 frame of the tension reduction machine.

4. The precise control method for the head and tail thickening end control model of the tension reduction machine based on online speed measurement feedback as described in claim 3, characterized in that: A check point is set at the entrance roller conveyor of the tension reduction machine at a distance of L0 from the No. 1 frame of the tension reduction machine, where L0 is a known point less than or equal to 1m; The timing begins when the steel pipe head reaches the speed measuring device. The actual time when the steel pipe head reaches the L0 point is defined as T1, and the average speed of the steel pipe head at the L0 point is V0. Then, the accurate time T1 when the steel pipe head actually reaches the No. 1 frame of the tension reduction machine is equal to L0 divided by V0. The time compensation value is obtained by comparing the T1 value with the theoretically calculated t1 value from the original CEC model. and the The values ​​are automatically compensated to the start, arrival, and end times of the CEC head of each frame, where L0 is the distance between the verification point and frame 1 of the tensioning machine, V0 is the average velocity value of the steel pipe head just reaching the L0 point, and t1 is the theoretical calculation data of the original CEC model.

5. The precise control method for the head and tail thickening end control model of the tension reduction machine based on online speed measurement feedback as described in claim 1, characterized in that: For the tail of the steel pipe, the distance between the speed measuring device and the No. 1 frame of the tension reducing machine is L1. The loss of signals from the thermal detection device and the speed measuring device is used as the signal for the tail to pass through the fixed point. At this time, the time for the thickened section of the tail to reach the No. 1 frame is L1 divided by V0', where V0' is the measured inlet speed. Time error is , where V is the theoretically set inlet velocity; The The value is automatically compensated to the start time, arrival time and end time of the CEC tail of each rack, where L1 is the distance between the speed measuring device and the No. 1 rack of the tension reduction machine, V0' is the measured inlet speed and V is the theoretical set inlet speed.

6. The precise control method for the head and tail thickening end control model of the tension reduction machine based on online speed measurement feedback as described in claim 1, characterized in that: If the speed measuring device loses its signal but the thermal detection device still has a signal, it is assumed that the steel pipe is still passing through. If the speed measuring device's signal is intermittent, the speed measuring device continues to integrate according to the speed at the moment the signal is lost, ensuring the accuracy of the measured length.

7. The precise control method for the head and tail thickening end control model of the tension reduction machine based on online speed measurement feedback as described in claim 1, characterized in that: When the speed measuring device fails to work, the thermal detection device triggers the CEC to work by adding a fixed delay to its signal.

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