A system and method suitable for damping vibrations in an AGC hydraulic cylinder of a cold rolling mill

Abstract

This invention relates to a system suitable for suppressing the vibration of AGC hydraulic cylinders in cold rolling mills, comprising a hydraulic suppression servo valve and a hydraulic suppression controller. The hydraulic suppression controller controls the hydraulic suppression servo valve to output pressure and flow opposite to the vibration direction of the AGC hydraulic cylinder based on the position information of the AGC hydraulic cylinder, thereby suppressing the vibration of the AGC hydraulic cylinder. This invention employs a hydraulic suppression system that reduces mill system vibration while maintaining a constant rolling speed and increasing the push-up and push-down strokes of the hydraulic cylinder. Furthermore, the hydraulic suppression system is separated from the mill's own AGC system, minimizing its impact. When the mill's hydraulic system vibrates, the position signal is fed back to the hydraulic suppression system, transforming the position signal into a suppression signal with equal frequency but opposite phase. This causes the hydraulic suppression servo valve to generate pressure and flow opposite to the vibration, reducing the system vibration amplitude and thus suppressing the vibration of the hydraulic system.

Description

Technical Field

[0001] This invention relates to the field of cold rolling technology, specifically to a system and method suitable for suppressing the vibration of AGC hydraulic cylinders in cold rolling mills. Background Technology

[0002] Currently, almost all cold rolling mills may face vibration problems. When the rolling speed of the mill increases, the control system gain increases, or the AGC cylinder exceeds a certain stroke, the system will vibrate, seriously affecting the normal production of the unit. This will significantly affect the thickness and shape of the strip, thus limiting product quality and steel output. Now, there is a method to suppress vibration and overcome this phenomenon, ensuring that the mill maintains stable rolling under high-speed, high-gain, and high-stroke rolling.

[0003] To solve vibration problems, it's essential to first understand them. Various forms of vibration can occur during strip rolling, each with different characteristics and causes. Based on the load transmission system, they can be categorized into torsional vibration of the mill's active drive system and vibration of the mill's vertical system. This patent primarily studies the vibration of the AGC hydraulic system of the push-up or press-down hydraulic cylinders in a cold rolling mill: when the rolled strip is thin and the stroke of the push-up or press-down hydraulic cylinders is high, vibration of the AGC hydraulic system is prone to occur. The vibration problem described in this paper mainly originates from an engineering project in a cold continuous rolling mill in Liyang: when the stroke of the push-up cylinder in a cold rolling mill exceeded 200mm, the mill's AGC hydraulic system generated a constant amplitude vibration with a frequency of 16Hz. Reducing the rolling speed or strip tension to decrease the system gain did not significantly reduce the vibration. Currently, the steel mill can only reduce the production of thin strip specifications to specifically mitigate the hydraulic system vibration caused by the high stroke of the push-up cylinder. Other literature indicates that in a certain 1550mm pickling and rolling mill unit at Baosteel, the hydraulic system of the pressing AGC (Automatic Guided Cylinder) experienced oscillations after the pressing cylinder exceeded a certain stroke. This demonstrates that vibrations in the hydraulic system of cold rolling mills are quite common in actual production practice and have long been a focus of attention for experts and scholars.

[0004] The vibration frequency of AGC hydraulic systems is relatively low, typically between 5 and 40 Hz, and its basic mechanism is self-excited vibration. From a physics perspective, many factors contribute to the vibration of hydraulic systems. Vibration occurs when parameters of the rolling mill itself reach critical values, such as rolling speed, tension, coefficient of friction, and oil column height. Among these, the hydraulic system, oil column height, and natural frequency have the most significant impact.

[0005] Current research on system vibration, both domestically and internationally, largely employs the method of constructing a system mechanical model. This model simplifies the components of the rolling mill into a multi-degree-of-freedom system, and then studies related instability factors based on control theory. However, scholars both at home and abroad have made appropriate simplification assumptions in their vibration model studies, often isolating a single aspect without comprehensively considering the various coupling factors that arise in reality. Consequently, the simulation results from these models are often rather simplistic.

[0006] Chinese patent CN201310546825 describes a method for suppressing rolling mill vibration. This method introduces the collected vibration signal into the system's execution unit to reduce system vibration by addressing both sheet tension and rolling speed. However, this method involves adjusting the rolling speed; when the system vibrates, the rolling speed is often reduced to ensure system stability. The hydraulic suppression system in this patent, however, can suppress vibration of the rolling mill's hydraulic system while maintaining a constant rolling speed, thereby ensuring sheet quality and production efficiency.

[0007] Chinese patent CN107983781 describes a method for suppressing the third octave vibration of a rolling mill system, with the third octave vibration range being 125–240 Hz. This patent, however, targets hydraulic system vibrations in the 5–40 Hz range. The method involves introducing the acquired acceleration signal into the system's high-frequency response servo valve, thereby increasing the damping of the hydraulic system to reduce vibration energy and suppress the third octave vibration of the rolling mill. However, this patent only addresses the adjustment of hydraulic system damping. Third octave vibrations often have significant vibration energy, and simply increasing the damping of the hydraulic system may not always result in a noticeable vibration reduction effect. In contrast, the hydraulic suppression system in this patent acquires position signals. After processing the position signals with equal frequency and out-of-phase characteristics, the position signals are transmitted to the AGC hydraulic main cylinder through the hydraulic suppression servo valve, effectively "absorbing" system vibrations—a different vibration reduction principle from that patent.

[0008] Chinese patent CN115625216 describes a method for suppressing mill vibration using reverse phase. This method primarily addresses the mill resonance problem in hot rolling mills. The solution involves using an inversely processed acceleration signal to generate vibrations in the mill's AGC cylinder that are opposite in direction to the mill's resonance, with equal amplitude, thus "cancelling" each other. However, this patent addresses the vibration induced by the mill's AGC hydraulic system. Its solution involves using an additional servo valve to reduce and suppress the AGC cylinder vibration—that is, reducing cylinder vibration rather than causing it to vibrate to cancel out the overall mill vibration. Furthermore, this patent constructs a separate hydraulic system, applying the vibration signal to a hydraulic suppression servo valve connected in parallel with the AGC hydraulic system's servo valve, minimizing its impact on the mill's AGC system itself. In contrast, the aforementioned patent directly applies the acceleration signal to the mill's AGC servo valve, which will inevitably have some impact on the AGC system itself.

[0009] Chinese patent CN102755995 describes a method for suppressing mill vibration by adding servo valves, hydraulic cylinders, and suppression controllers. The key aspect of this method is the addition of hydraulic cylinders as actuators, which must be positioned within a bearing housing. The orientation of the hydraulic cylinders must align with the direction of the mill vibration, undoubtedly increasing the installation complexity. The principle behind this patent's vibration suppression is to generate additional hydraulic vibrations based on the mill's vibration signal to "cancele" the mill vibration. However, the hydraulic system has a narrow response frequency range and cannot completely eliminate high-frequency mill vibrations. Furthermore, placing the hydraulic cylinders in the bearing housing is not suitable for all types of mills. Mill structures are typically compact, and the space in the bearing housing is limited, failing to meet the requirements of all mill structures.

[0010] In view of this, the present invention is hereby proposed. Summary of the Invention

[0011] The purpose of this invention is to provide a system and method suitable for suppressing the vibration of AGC hydraulic cylinders in cold rolling mills, so as to solve the technical problems mentioned in the background art.

[0012] To achieve one of the above objectives, the present invention provides the following technical solution:

[0013] A system suitable for suppressing vibration of an AGC hydraulic cylinder in a cold rolling mill is provided. The AGC hydraulic cylinder includes a position sensor for sensing the position information of the AGC hydraulic cylinder. The system also includes a hydraulic suppression servo valve and a hydraulic suppression controller. The hydraulic suppression controller controls the hydraulic suppression servo valve to output pressure and flow opposite to the vibration direction of the AGC hydraulic cylinder based on the position information of the AGC hydraulic cylinder, thereby suppressing the vibration of the AGC hydraulic cylinder.

[0014] Preferably, the hydraulic suppression servo valve is rigidly connected to the AGC hydraulic cylinder.

[0015] Preferably, the system further includes a filter for identifying the frequency of vibration of the AGC hydraulic cylinder and filtering the frequency band during normal operation of the AGC hydraulic cylinder.

[0016] Preferably, it further includes a phase compensation device, which is used to compensate for the phase angle delay caused by signal acquisition and processing delay.

[0017] Preferably, the system also includes a back pressure module, which ensures stable system operation and prevents the AGC hydraulic cylinder from being in a weightless state during operation.

[0018] Preferably, the system further includes a limiting module located upstream of the hydraulic suppression servo valve.

[0019] Preferably, the hydraulic suppression servo valve is directly fixed to the AGC hydraulic cylinder.

[0020] Preferably, the position sensor is a magnetic grating ruler.

[0021] To achieve the second objective mentioned above, the present invention provides the following technical solution:

[0022] A method suitable for suppressing vibration of AGC hydraulic cylinders in cold rolling mills includes the following steps:

[0023] Step 100: Install a position sensor in the AGC hydraulic cylinder, and the position sensor sends the position information of the AGC hydraulic cylinder to the hydraulic suppression controller;

[0024] Step 200: The hydraulic suppression controller determines whether the AGC hydraulic cylinder is vibrating based on the position information of the AGC hydraulic cylinder;

[0025] Step 300: If vibration occurs, the hydraulic suppression controller sends a vibration suppression signal with the same frequency and opposite phase to the hydraulic suppression servo valve. The hydraulic suppression servo valve outputs pressure and flow opposite to the vibration direction of the AGC hydraulic cylinder according to the vibration suppression signal, thereby suppressing the vibration of the AGC hydraulic cylinder.

[0026] If no vibration occurs, the hydraulic suppression servo valve will not be opened.

[0027] Preferably, in step 100:

[0028] The position sensor is a magnetic grating ruler;

[0029] In step 200:

[0030] Before the hydraulic suppression controller determines whether the AGC hydraulic cylinder is vibrating based on the position information of the AGC hydraulic cylinder, the position information of the AGC hydraulic cylinder needs to be filtered and phase compensation device.

[0031] In step 300:

[0032] Before receiving the vibration suppression signal, the vibration suppression signal of the hydraulic suppression servo valve must pass through the amplitude limiting module, which is used to protect the hydraulic suppression servo valve from being burned out.

[0033] Compared with existing technologies, this invention proposes a system and method suitable for suppressing the vibration of AGC hydraulic cylinders in cold rolling mills. It employs a hydraulic suppression system to reduce mill system vibration while maintaining a constant rolling speed and increasing the push-up and push-down strokes of the hydraulic cylinders. Furthermore, the hydraulic suppression system is separated from the mill's own AGC system, minimizing its impact. When the mill's hydraulic system vibrates, the position signal is fed back to the hydraulic suppression system, transforming it into a suppression signal with equal frequency and opposite phase. This causes the hydraulic suppression servo valve to generate pressure and flow opposite to the vibration direction, reducing the system vibration amplitude and thus effectively suppressing hydraulic system vibration.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a system suitable for suppressing the vibration of an AGC hydraulic cylinder in a cold rolling mill, provided as an embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of the upward movement of an AGC hydraulic cylinder in a system suitable for suppressing vibration of an AGC hydraulic cylinder in a cold rolling mill, provided as an embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram of the downward movement of an AGC hydraulic cylinder in a system suitable for suppressing vibration of an AGC hydraulic cylinder in a cold rolling mill, provided as an embodiment of the present invention.

[0039] Figure 4 A system flowchart of a method suitable for suppressing vibration of AGC hydraulic cylinders in a cold rolling mill is provided in one embodiment of the present invention.

[0040] Figure 5 The image shows a comparison of vibration suppression effects in a method for suppressing vibration of an AGC hydraulic cylinder in a cold rolling mill, provided as an embodiment of the present invention.

[0041] The attached figures are labeled as follows:

[0042] 1. Frame; 2. Rolls; 3. AGC hydraulic cylinder; 4. AGC hydraulic servo valve; 5. Hydraulic suppression servo valve; 6. Magnetic scale position signal; 7. Vibration suppression signal; 8. Hydraulic suppression controller. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] like Figure 1 As shown, one embodiment of the present invention provides a system suitable for suppressing the vibration of an AGC hydraulic cylinder 3 in a cold rolling mill. The AGC hydraulic cylinder 3 includes a position sensor for sensing the position information of the AGC hydraulic cylinder 3. The system includes a hydraulic suppression servo valve 5 and a hydraulic suppression controller 8. The hydraulic suppression controller 8 controls the hydraulic suppression servo valve 5 to output pressure and flow rate opposite to the vibration direction of the AGC hydraulic cylinder 3 based on the position information of the AGC hydraulic cylinder 3, thereby suppressing the vibration of the AGC hydraulic cylinder 3.

[0045] In a preferred embodiment of the above embodiments of the present invention, the following modules are further included:

[0046] 1. A filter, wherein the filter is used to identify the frequency of vibration of the AGC hydraulic cylinder 3 and filter the frequency band of normal operation of the AGC hydraulic cylinder 3.

[0047] 2. A phase compensation device, which is used to compensate for the phase angle delay caused by signal acquisition and processing delay.

[0048] 3. Back pressure module: The back pressure module can ensure the stable operation of the system and ensure that the AGC hydraulic cylinder 3 is not in a weightless state when it is working.

[0049] 4. Amplitude limiting module, which is located before the hydraulic suppression servo valve 5.

[0050] In another preferred embodiment of the invention, the hydraulic suppression servo valve 5 is rigidly connected to the AGC hydraulic cylinder 3, and the hydraulic suppression servo valve 5 is directly fixed on the AGC hydraulic cylinder 3. The position sensor is a magnetic grating ruler.

[0051] In this invention, when the AGC hydraulic system vibrates, i.e., when the AGC hydraulic cylinder 3 undergoes stable periodic reciprocating motion, the hydraulic suppression servo valve 5 outputs pressure and flow in the opposite direction to that of the AGC hydraulic cylinder 3. When the AGC hydraulic system vibrates and the AGC hydraulic cylinder 3 moves upward, as... Figure 2 As shown, the upper region inside the cylinder is the pressureless region, and the lower region inside the cylinder is the pressure region. The upper arrow indicates the direction of movement of the AGC hydraulic oil, and the middle arrow indicates the direction of pressure exerted by the hydraulic suppression servo valve 5 on the piston of the AGC hydraulic cylinder 3. Figure 2 In the AGC hydraulic cylinder 3, the rodless chamber is pressurized while the rod chamber is depressurized, causing the AGC hydraulic cylinder 3 to move upwards. The hydraulic suppression system, based on a position signal of opposite phase, inputs a certain pressure and flow rate to the rod chamber of the AGC hydraulic cylinder 3 to prevent the movement of the hydraulically pushed cylinder in the AGC system, thereby suppressing vibrations in the hydraulic system.

[0052] When the AGC hydraulic system vibrates, and AGC hydraulic cylinder 3 moves downward, such as Figure 3 As shown, the hydraulic suppression servo valve 5 of the hydraulic suppression system inputs a certain pressure and flow rate into the rodless chamber according to the position signal with opposite phase, in order to prevent the AGC hydraulic cylinder 3 from moving downward. It can be seen that when the AGC hydraulic cylinder 3 moves up and down in a stable period, i.e., the AGC hydraulic system vibrates, the hydraulic suppression system suppresses the vibration of the hydraulic system according to the vibration position signal.

[0053] In this invention, the existing rolling mill stand 1, rolls 2, AGC hydraulic cylinder 3, and AGC hydraulic servo valve 4 are incorporated. The AGC hydraulic cylinder 3 is equipped with a position sensor, i.e., a magnetic scale. The magnetic scale senses the position signal of the AGC hydraulic cylinder 3. The frequency and amplitude of the magnetic scale position signal 6 adjust the pressure and flow rate of the hydraulic suppression servo valve 5 in real time, thus better suppressing the vibration of the AGC hydraulic cylinder 3 under different conditions. Furthermore, this patent also includes a filtering element, i.e., a filter. When the AGC hydraulic cylinder 3 moves up and down normally during normal operation and adjustment, since this adjustment does not produce a stable movement cycle, the filtering element can normally avoid this during system identification, preventing the hydraulic suppression servo valve 5 from preventing the AGC hydraulic cylinder 3 from operating normally.

[0054] When there is no vibration, the hydraulic damping system is shut down and in a non-operating state.

[0055] Hydraulic vibration suppression systems can identify hydraulic vibrations based on their inherent characteristics. Hydraulic vibration frequencies are relatively low, typically 5–40 Hz. In contrast, the vibration frequencies of the vertical systems in rolling mills, typically in their 3rd and 5th harmonic bands, are very high, with the lowest frequency range exceeding 120 Hz. The lower-frequency vibrations of the main drive system in rolling mills often accompany the entire rolling process and are not caused by the increased stroke of the AGC hydraulic cylinder. Similarly, because the hydraulic suppression system is simpler than the overall rolling mill AGC system, its response frequency range is wider than the 5–40 Hz vibration frequency range of the AGC hydraulic system, providing full coverage. This avoids the awkward situation where the rolling mill generates high-frequency vibrations, but the hydraulic suppression system itself has a low output frequency and cannot meet the frequency requirements for vibration suppression.

[0056] The hydraulic suppression system has the function of Fourier transform, which can convert the position signal in the time domain into a frequency domain signal and identify its frequency. When necessary, it can also compensate for the frequency of the vibration position signal to prevent the phenomenon of missing or lost frequency during the transmission and processing of the signal.

[0057] The hydraulic suppression system and the rolling mill AGC system are separate and independent of each other, each using a separate servo valve. Furthermore, the control module and filtering module of the hydraulic suppression system are also separate from those of the rolling mill AGC system. This minimizes the impact of the hydraulic suppression system on the rolling mill AGC system.

[0058] To address the hydraulic vibration issues inherent in previous rolling mill AGC (Automatic Gauge Control) systems, this invention incorporates a hydraulic suppression system. This patented system can steadily increase the rolling stroke of the AGC hydraulic cylinder 3, building upon the existing critical stroke range of the AGC system's hydraulic cylinder, thereby enabling better rolling of various thin strip steel specifications. Furthermore, this system allows rolling without reducing the rolling speed, and because the hydraulic suppression system and the AGC system are separate systems, it minimizes the impact on the rolling mill's AGC system.

[0059] In the hydraulic suppression system, the position signal from the position sensor is obtained from the magnetic scale of the AGC hydraulic cylinder 3, collecting the position signal of the hydraulic vibration on site. The collected signal is filtered to remove high and low frequency signal components, and then the phase angle caused by the delay is compensated by the phase compensation device. Then the position signal is transmitted to the hydraulic suppression controller 8. The controller uses Fourier transform to determine the vibration status of the system, thereby determining whether the AGC hydraulic system is vibrating: when the system vibration frequency is between 5Hz and 40Hz, reaches a certain amplitude, and the vibration continues for a certain period of time, the hydraulic suppression system determines that the mill is vibrating. At this time, the controller begins to invert the position signal and, after processing it with a certain algorithm, the controller begins to send a signal to the hydraulic suppression servo valve 5. The system includes a proportional element, which can amplify or reduce the signal gain accordingly before it flows to the servo valve. To prevent the servo valve from burning out due to excessive current flowing into it, a limiting module is often added before the servo valve. The signal flowing through the limiting module is then fed into the servo valve. The selection of the servo valve can refer to the domestic Huade series servo valves. The servo valve's natural frequency only needs to be a minimum of 100Hz, as the frequency of the system's hydraulic vibration is relatively low, which meets the system's response speed requirements. The valve itself has a small flow rate, minimizing its impact on the rolling mill's AGC control system. For different rolling mills, the rated flow rate of the hydraulic suppression servo valve 5 is approximately in the range of 5L / min-20L / min. Furthermore, the rated flow rate of the servo valve should not be set too high; excessively high flow rates not only fail to effectively suppress rolling mill vibration but also affect the response speed and control accuracy of the AGC system, impacting strip quality. Extensive simulation experiments conducted on a cold rolling mill in a certain plant revealed a positive correlation between flow rate and vibration amplitude suppression to some extent. Data showed that when suppressing vibrations with an amplitude of approximately 100 micrometers (extracted signal from a magnetic scale) and a frequency of 12Hz, the rated flow rate of the servo valve was selected as 5L / min. The output flow rate of the hydraulic suppression servo valve 5 is not constant; it initially outputs a maximum flow rate, then gradually decreases, finally maintaining a smaller output flow rate to stabilize the system. This is because the initial vibration amplitude is larger, resulting in a higher servo valve output flow rate. The output flow can reduce the system amplitude, weaken the vibration, and gradually reduce the position signal, thereby gradually reducing the flow output of the servo valve until the flow stabilizes and maintains a relatively balanced state.

[0060] Furthermore, this invention uses AMEsim software and combines it with on-site data to simulate the rolling mill. The accuracy of the results is confirmed by comparing the software simulation analysis with the on-site data. In this scenario, a hydraulic damping system is added, and the effect of adding a system is compared with that without a hydraulic damping system to simulate the vibration reduction effect. Figure 5The graphs shown are simulation outputs from a rolling mill. The extracted signal is a magnetic scale (roll gap). The vertical axis represents micrometers, and the horizontal axis represents time. The system input is a square wave signal. Comparing the two graphs, the left graph shows the curve with a hydraulic suppression system. The right graph shows the curve without a hydraulic suppression system. In this case, the system vibrates with an amplitude of approximately 100 micrometers (extracted signal: magnetic scale) and a frequency of 12Hz. It is evident that the hydraulic suppression system has a significant suppression effect and provides effective control.

[0061] like Figure 4 As shown, this embodiment of the invention provides a method suitable for suppressing the vibration of the AGC hydraulic cylinder 3 in a cold rolling mill, comprising the following steps:

[0062] Step 100: Install a position sensor in the AGC hydraulic cylinder 3, and the position sensor sends the position information of the AGC hydraulic cylinder 3 to the hydraulic suppression controller 8;

[0063] Step 200: The hydraulic suppression controller 8 determines whether the AGC hydraulic cylinder 3 is vibrating based on the position information of the AGC hydraulic cylinder 3;

[0064] Step 300: If vibration occurs, the hydraulic suppression controller 8 sends a vibration suppression signal 7 with the same frequency and opposite phase to the hydraulic suppression servo valve 5. The hydraulic suppression servo valve 5 outputs pressure and flow opposite to the vibration direction of the AGC hydraulic cylinder 3 according to the vibration suppression signal 7, thereby suppressing the vibration of the AGC hydraulic cylinder 3.

[0065] If no vibration occurs, the hydraulic suppression servo valve 5 will not be opened.

[0066] In the preferred embodiments described above:

[0067] In step 100:

[0068] The position sensor is a magnetic grating ruler;

[0069] In step 200:

[0070] Before the hydraulic suppression controller 8 determines whether the AGC hydraulic cylinder 3 vibrates based on the position information of the AGC hydraulic cylinder 3, the position information of the AGC hydraulic cylinder 3 needs to be filtered and phase compensation device.

[0071] In step 300:

[0072] Before receiving the vibration suppression signal 7, the hydraulic suppression servo valve 5 must pass through the amplitude limiting module, which is used to protect the hydraulic suppression servo valve 5 from being burned out.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system suitable for damping the vibrations of an AGC hydraulic cylinder in a cold rolling mill, in which an AGC hydraulic cylinder is included, a position sensor for sensing the position information of the AGC hydraulic cylinder, characterized in that, The hydraulic suppression servo valve and the AGC hydraulic cylinder are rigidly connected.

2. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 1, characterized in that, The filter is used to identify the frequency of the AGC hydraulic cylinder vibration and filter the frequency band of the AGC hydraulic cylinder regular work.

3. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 2, characterized in that, The phase compensation device is used to compensate the phase angle lag caused by signal acquisition and processing delay.

4. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 3, characterized in that, The back pressure module ensures the stable operation of the system, and ensures that the AGC hydraulic cylinder will not be in a weightless state when working.

5. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 4, characterized in that, The amplitude limiting module is located before the hydraulic suppression servo valve.

6. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 5, characterized in that, The hydraulic suppression servo valve is directly fixed on the AGC hydraulic cylinder.

7. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 6, characterized in that, The position sensor is a magnetic grating ruler.

8. A system suitable for damping the vibrations of the AGC hydraulic cylinders in a cold rolling mill according to claim 7, characterized in that, The method comprises the following steps:

9. A method suitable for damping the vibrations of an AGC hydraulic cylinder in a cold rolling mill, characterized in that, Step 100: a position sensor is arranged in the AGC hydraulic cylinder, which sends the position information of the AGC hydraulic cylinder to the hydraulic suppression controller; Step 200: the hydraulic suppression controller determines whether the AGC hydraulic cylinder vibrates according to the position information of the AGC hydraulic cylinder; Step 300: if vibration occurs, the hydraulic suppression controller sends a vibration suppression signal with the same frequency and opposite phase to the hydraulic suppression servo valve, and the hydraulic suppression servo valve outputs pressure and flow opposite to the vibration direction of the AGC hydraulic cylinder according to the vibration suppression signal, so as to suppress the vibration of the AGC hydraulic cylinder; If no vibration occurs, the hydraulic suppression servo valve is not started.

10. The method of claim 9, wherein: In the step 100: The position sensor is a magnetic grating ruler; In the step 200: Before the hydraulic suppression controller determines whether the AGC hydraulic cylinder vibrates according to the position information of the AGC hydraulic cylinder, the position information of the AGC hydraulic cylinder needs to pass through the filter and the phase compensation device; In the step 300: Before the hydraulic suppression servo valve receives the vibration suppression signal, the vibration suppression signal needs to pass through the amplitude limiting module, which is used to protect the hydraulic suppression servo valve from being burned out. ​

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