A control method for quickly diagnosing response speed of AGC hydraulic system of thick plate

Abstract

The present application relates to a kind of fast diagnosis thick plate AGC hydraulic system response speed control method, belong to rolling mill control technical field.It includes the following steps:S1, the upper and lower roller system on finishing mill is adjusted to be loaded state;S2, in TDC control system, periodic waveform is set to AGC hydraulic oil column, so that finishing mill drive side and non-drive side hydraulic cylinder is rotated on the basis of hydraulic oil column;S3, feedback test is done to the rotation, and the feedback curve executed by AGC hydraulic system is recorded;S4, whether AGC hydraulic system response speed meets preset requirement is judged according to the feedback curve.The present application can quickly diagnose AGC hydraulic system response speed, so as to judge whether preset judging condition is satisfied according to actual response speed, and then the efficiency of detection and maintenance to AGC servo valve or AGC hydraulic cylinder is improved.

Description

Technical Field

[0001] This invention belongs to the field of rolling mill control technology and relates to a control method for rapidly diagnosing the response speed of a thick plate AGC hydraulic system. Background Technology

[0002] The thick plate AGC (Automatic Thickness Control) hydraulic control system is one of the important pieces of equipment for controlling the thickness of thick plate rolling production lines. The thick plate AGC hydraulic system consists of AGC hydraulic cylinders, hydraulic displacement sensors, rolling force sensors, TDC controllers, AGC hydraulic stations, AGC servo valves, and other detection units, control units, and execution units.

[0003] Thick plate rolling requires a rapid response from the AGC hydraulic system for thickness control. However, existing thick plate AGC hydraulic control systems cannot provide real-time data on the system's response speed during production, making it impossible to determine whether the process requirements are met. Especially after prolonged use, the response speed of the thick plate AGC hydraulic control system significantly decreases, impacting rolling efficiency, and it's difficult to determine whether this is due to insufficient response speed to meet process requirements. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a control method for rapidly diagnosing the response speed of a thick plate AGC hydraulic system, which can quickly diagnose the response speed of the thick plate AGC hydraulic system, thereby determining whether the response speed meets the process requirements, and thus reducing the maintenance difficulty of the thick plate AGC hydraulic system.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A control method for rapidly diagnosing the response speed of a thick plate AGC hydraulic system includes the following steps:

[0007] S1. Adjust the upper and lower roll systems of the finishing mill to the loaded state;

[0008] S2. Set a periodic waveform for the AGC hydraulic oil column in the TDC control system so that the hydraulic cylinders on the drive side and non-drive side of the finishing mill rotate based on the hydraulic oil column.

[0009] S3. Perform a feedback test on the rotation and record the feedback curve executed by the AGC hydraulic system;

[0010] S4. Determine whether the response speed of the AGC hydraulic system meets the preset requirements based on the feedback curve.

[0011] Furthermore, in S1, the adjustment includes:

[0012] S11. After the finishing mill roll change is completed and before rolling the steel plate, the AGC hydraulic cylinder is injected with an initial oil column to press down the finishing mill upper roll system. When the finishing mill upper and lower roll systems just come together, the operation is stopped.

[0013] S12. Perform oil unloading operation on the hydraulic cylinders on the transmission side and non-transmission side until the rolling force on both the transmission side and non-transmission side is zero. Then, push the main motors of the upper and lower sides to rotate and control the upper and lower roller systems to perform crawling rotation.

[0014] S13. When the upper and lower rollers are close to touching and the pressing force is detected as zero, perform the AGC hydraulic cylinder jogging oil supply operation.

[0015] S14. Perform the tilting operation of the upper and lower roll systems to balance the rolling forces on both the drive side and the non-drive side.

[0016] Furthermore, in S2, if the periodic waveform is a step square wave, when the step execution feedback of the oil column in the AGC system reaches 90% of the amplitude, the actual execution time of the transmission side and the non-transmission side is analyzed, and the actual execution time is compared with the response speed requirement of the AGC hydraulic system to obtain the diagnostic result.

[0017] Furthermore, the response speed requirements for the AGC hydraulic system include:

[0018] When the actual execution time is less than or equal to 100ms, the diagnostic result is: AGC execution speed is relatively fast;

[0019] When the actual execution time is less than or equal to 120ms and greater than 100ms, the diagnostic result is: AGC execution speed meets the basic requirements;

[0020] When the actual execution time is less than or equal to 150ms but greater than 120ms, the diagnostic result is: the AGC execution speed is slow. The servo system should be tested and the hydraulic servo valve group should be replaced.

[0021] If the actual execution time is greater than or equal to 150ms, the diagnosis result is: AGC execution speed is very slow, replace the hydraulic cylinder and hydraulic servo valve group.

[0022] Furthermore, when the periodic waveform in S2 is a sine wave, the actual feedback sine wave curves of the transmission side and the non-transmission side are analyzed. The actual peaks or troughs in the actual feedback sine wave curves are analyzed, and the phase difference between the actual peak and the set sampling peak, or the phase difference between the actual trough and the set sampling trough, is calculated. The phase difference is compared with the response speed diagnostic standard of the AGC hydraulic system to obtain a diagnostic conclusion.

[0023] Furthermore, the diagnostic criteria for the response speed of the AGC hydraulic system include:

[0024] When the phase difference is less than or equal to 45°, the diagnostic conclusion is: AGC execution speed is relatively fast;

[0025] When the phase difference is less than or equal to 60° and greater than 45°, the diagnostic conclusion is: the AGC execution speed meets the basic requirements;

[0026] When the phase difference is less than or equal to 80° and greater than 60°, the diagnosis is: the AGC execution speed is slow. The servo system should be tested and the hydraulic servo valve group should be replaced.

[0027] When the phase difference is greater than 80°, the diagnosis is: the AGC execution speed is very slow, and the hydraulic cylinder and hydraulic servo valve group should be replaced.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention, by setting step position curves and sine wave position curves within the TDC control system and then observing the actual position curves of the hydraulic cylinders on the transmission and non-transmission sides, can quickly diagnose the response speed of the AGC hydraulic system. Based on the actual response speed, it can determine whether the preset judgment conditions are met, thereby improving the efficiency of testing and maintaining AGC servo valves or AGC hydraulic cylinders.

[0030] 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

[0031] 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:

[0032] Figure 1 For the step test and feedback curve of the hydraulic oil column on the transmission side;

[0033] Figure 2 For the step test and feedback curve of the hydraulic oil column on the non-transmission side;

[0034] Figure 3 Feedback curve for the step test of the oil column on the transmission side;

[0035] Figure 4 Feedback curve for the non-drive side oil column step test execution;

[0036] Figure 5 For the sinusoidal wave test and feedback curve of the hydraulic oil column on the transmission side;

[0037] Figure 6For the non-transmission side hydraulic oil column sinusoidal wave test and feedback curve;

[0038] Figure 7 The feedback curve for the sinusoidal wave test of the oil column on the transmission side;

[0039] Figure 8 The feedback curve for the non-drive side oil column sinusoidal wave test is shown.

[0040] Figure 9 This is a schematic diagram illustrating the steps of this method. Detailed Implementation

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Please see Figures 1-9 This is a control method for rapidly diagnosing the response speed of a thick plate AGC hydraulic system, the implementation of which includes:

[0045] Adjust the upper and lower roll systems of the finishing mill to a loaded state:

[0046] 1. After the finishing mill roll change is completed and before rolling the steel plate, first inject an initial oil column into the AGC hydraulic cylinder. For example, the initial oil column on the drive side and the oil column on the non-drive side are both about 15mm. Manually press down the upper finishing mill roll system. When the upper and lower finishing mill roll systems just come together, stop the operation. At this time, the rolling force sensor will report a rolling force of about 200 tons.

[0047] 2. Manually perform the oil unloading operation by slightly unloading the hydraulic cylinders on both the drive side and the non-drive side until the rolling force on both sides is zero. At this time, the upper and lower roller systems are not effectively in contact.

[0048] 3. The operator drives the upper and lower main motors to rotate, and the upper and lower roller systems perform crawling rotation at a speed of 20 revolutions per minute.

[0049] 4. The upper and lower rollers rotate. At this time, the upper and lower rollers are not in contact, and the rolling force is zero. At this time, the operation is to perform the AGC hydraulic cylinder jogging operation until the total rolling force is about 2000 tons.

[0050] 5. At this time, the rolling forces on the drive side and the non-drive side may be unbalanced. The operator performs the tilting operation of the upper and lower roll system to make the rolling forces on the drive side and the non-drive side about 1000 tons respectively. At this time, the initial oil column on the drive side is 16.9mm and the initial oil column on the non-drive side is 17.6mm.

[0051] 6. At this time, the upper and lower roll systems of the finishing mill are rotating at a speed of 20 revolutions per minute; and the upper and lower roll systems are under load, with a total rolling force of about 2,000 tons, and rolling forces of about 1,000 tons on the drive side and the non-drive side respectively.

[0052] After the upper and lower roller systems are adjusted, a periodic waveform is set for the AGC hydraulic oil column in the TDC control system, so that the hydraulic cylinders on the drive side and non-drive side of the finishing mill rotate on the basis of the hydraulic oil column; then, a feedback test is performed on the step rotation, and the feedback curve of the AGC hydraulic system is recorded; finally, the response speed of the AGC hydraulic system is judged according to the feedback curve to determine whether it meets the preset requirements.

[0053] The periodic waveform can be set as a step square wave or a sine wave. The implementation methods for each are described below:

[0054] I. Step position curve setting and execution feedback test

[0055] Initial oil columns have been injected into the hydraulic cylinders on both the drive and non-drive sides of the finishing mill (the initial oil column on the drive side is 16.9 mm, and the initial oil column on the non-drive side is 17.6 mm). The upper and lower roll systems are in contact and under load. The total rolling force is about 2,000 tons, with the rolling forces on the drive and non-drive sides being about 1,000 tons each. The upper and lower roll systems are rotating at a speed of 20 revolutions per minute.

[0056] Based on the initial oil column mentioned above, a periodic step square wave is set for the AGC hydraulic oil column in the TDC control system. By observing and analyzing the execution feedback curve of the AGC hydraulic system, the execution speed of the AGC hydraulic control system can be diagnosed.

[0057] The AGC hydraulic oil column is configured to exhibit a periodic step square wave characteristic. This step square wave is periodic with a period of 6 seconds, including a 3-second peak and a 3-second trough. The peak amplitude is 0.1 mm. This means that the hydraulic cylinders on both the drive and non-drive sides of the finishing mill perform a step rotation with a period of 6 seconds and an amplitude of 0.1 mm, based on the initial oil column (16.9 mm on the drive side and 17.6 mm on the non-drive side). During this process, the AGC hydraulic system's execution feedback curve is recorded. The step test and feedback curves for the hydraulic oil columns on both the drive and non-drive sides are shown below. Figure 1 and Figure 2 As shown.

[0058] Through extensive practical verification, when the step feedback of the oil column in the AGC system reaches 90% of the amplitude, i.e., 0.09mm, the execution speed of the AGC hydraulic control system can be diagnosed by analyzing the actual execution time on the transmission side and the non-transmission side. The step feedback judgment requirements for the execution speed of the AGC system are shown in Table 1 below.

[0059] Table 1 - Requirements for Speed ​​Step Feedback Judgment in AGC System

[0060]

[0061] Analyzing the example, if the AGC system's hydraulic column step response reaches 90% of the amplitude (0.09mm), the actual execution time on the drive side is 200ms, and on the non-drive side it is 240ms. This indicates that the actual execution times on both the drive and non-drive sides are greater than 150ms. Therefore, the diagnosis is that the AGC execution speed on both the drive and non-drive sides is very slow, requiring replacement of the hydraulic cylinders and hydraulic servo valve assemblies at both locations. Figure 3 and Figure 4 As shown, the actual response times of both the drive side and the non-drive side exceed the minimum standard requirement of 120ms for the system. Therefore, it is necessary to replace the hydraulic cylinders and servo valve groups on both the drive side and the non-drive side of the finishing mill to improve the system response speed.

[0062] II. Sine Wave Curve Setting and Execution Feedback Test

[0063] Initial oil columns have been injected into the hydraulic cylinders on both the drive and non-drive sides of the finishing mill (the initial oil column on the drive side is 16.9 mm, and the initial oil column on the non-drive side is 17.6 mm). The upper and lower roll systems are in contact and under load. The total rolling force is about 2,000 tons, with the rolling forces on the drive and non-drive sides being about 1,000 tons each. The upper and lower roll systems are rotating at a speed of 20 revolutions per minute.

[0064] Based on the initial oil column mentioned above, a periodic sine wave is set for the AGC hydraulic oil column in the TDC control system. By observing and analyzing the execution feedback curve of the AGC hydraulic system, the execution speed of the AGC hydraulic control system can be diagnosed.

[0065] The AGC hydraulic oil column is set to exhibit a periodic sine wave characteristic. The sine wave is a periodic sine wave with a period of 200ms completing 360°. The amplitude of the sine wave's peak and trough is 0.1mm. That is, the hydraulic cylinders on both the drive and non-drive sides of the finishing mill rotate in a sine wave with a period of 200ms and a peak and trough of 0.1mm, based on the initial oil column (16.9mm on the drive side and 17.6mm on the non-drive side). During this process, the execution feedback curve of the AGC hydraulic system is recorded. The sine wave test and feedback curves of the hydraulic oil column on the drive and non-drive sides are shown below. Figure 5 and Figure 6 .

[0066] Through extensive practical verification, when the AGC system performs a sine wave setting test, the execution speed of the AGC hydraulic control system can be diagnosed by analyzing the phase difference between the actual feedback sine wave curves from the transmission side and the non-transmission side and the set sampling peak or trough. The sine wave feedback judgment criteria for the execution speed of the AGC system are shown in Table 2 below.

[0067] Table 2 - Criteria for Judging Sine Wave Feedback Execution Speed ​​of AGC System

[0068]

[0069] The formula for calculating phase difference is as follows:

[0070]

[0071] like Figure 7 and Figure 8 As shown, the time difference between the actual feedback sine wave curve from the transmission side and the set sampling peak is:

[0072] T 实际波峰 -T 设定波峰 =58ms, then Δα = 58 / 200 × 360 = 104.4°

[0073] The time difference between the actual feedback sine wave curve on the non-drive side and the set sampling peak is:

[0074] T 实际波峰 -T 设定波峰 =60ms, △α=60 / 200×360=108°

[0075] If the phase difference between the transmission side and the non-transmission side is greater than 80°, the diagnosis result is: the AGC execution speed at both locations is very slow, exceeding the minimum standard requirement of less than 60° for the system. After the oil column is set, the AGC system's execution tracking performance is very poor, and it is necessary to replace the hydraulic cylinders and hydraulic servo valve groups on both the transmission side and the non-transmission side.

[0076] 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 control method for rapidly diagnosing the response speed of a thick plate AGC hydraulic system, characterized in that: Includes the following steps: S1. Adjust the upper and lower roll systems of the finishing mill to the loaded state; S2. Set a periodic waveform for the AGC hydraulic oil column in the TDC control system so that the hydraulic cylinders on the drive side and non-drive side of the finishing mill rotate based on the hydraulic oil column. S3. Perform a feedback test on the rotation and record the feedback curve executed by the AGC hydraulic system; S4. Determine whether the response speed of the AGC hydraulic system meets the preset requirements based on the feedback curve; In S1, the adjustment includes: S11. After the finishing mill roll change is completed and before rolling the steel plate, the AGC hydraulic cylinder is injected with an initial oil column to press down the finishing mill upper roll system. When the finishing mill upper and lower roll systems just come together, the operation is stopped. S12. Perform oil unloading operation on the hydraulic cylinders on the transmission side and non-transmission side until the rolling force on both the transmission side and non-transmission side is zero. Then, push the main motors of the upper and lower sides to rotate and control the upper and lower roller systems to perform crawling rotation. S13. When the upper and lower rollers are close to touching and the pressing force is detected as zero, perform the AGC hydraulic cylinder jogging oil supply operation. S14. Perform the tilting operation of the upper and lower roll systems to balance the rolling forces on the drive side and the non-drive side; If the periodic waveform is a step square wave, then when the step execution feedback of the oil column in the AGC system reaches 90% of the amplitude, analyze the actual execution time on the transmission side and the non-transmission side, compare the actual execution time with the response speed requirement of the AGC hydraulic system, and obtain the diagnostic result. The response speed requirements for AGC hydraulic systems include: When the actual execution time is less than or equal to 100ms, the diagnostic result is: AGC execution speed is relatively fast; When the actual execution time is less than or equal to 120ms and greater than 100ms, the diagnostic result is: AGC execution speed meets the basic requirements; When the actual execution time is less than or equal to 150ms but greater than 120ms, the diagnostic result is: the AGC execution speed is slow. The servo system should be tested and the hydraulic servo valve group should be replaced. If the actual execution time is greater than or equal to 150ms, the diagnosis result is: AGC execution speed is very slow, replace the hydraulic cylinder and hydraulic servo valve group; When the periodic waveform is a sine wave, the actual feedback sine wave curves of the transmission side and the non-transmission side are analyzed. The actual peaks or troughs in the actual feedback sine wave curves are analyzed. The phase difference between the actual peak and the set sampling peak, or the phase difference between the actual trough and the set sampling trough, is calculated. The phase difference is compared with the response speed diagnostic standard of the AGC hydraulic system to obtain a diagnostic conclusion. AGC hydraulic system response speed diagnostic criteria include: When the phase difference is less than or equal to 45°, the diagnostic conclusion is: AGC execution speed is relatively fast; When the phase difference is less than or equal to 60° and greater than 45°, the diagnostic conclusion is: the AGC execution speed meets the basic requirements; When the phase difference is less than or equal to 80° and greater than 60°, the diagnosis is: the AGC execution speed is slow. The servo system should be tested and the hydraulic servo valve group should be replaced. When the phase difference is greater than 80°, the diagnosis is: the AGC execution speed is very slow, and the hydraulic cylinder and hydraulic servo valve group should be replaced.

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