20Hi Cold Rolling Mill AGC
AEMETEC digital hydraulic cold rolling mill automatic gauge control (AGC) system is AEMETEC brings together many years of metallurgy, national defense, machinery, energy, robots and other automation solution experience. By optimizing, summarize and improve, proposed a system composition, a new solution to the software control algorithm. Through actual debugging, use advanced and verified the reliability of the system.
AEMETEC digital hydraulic cold rolled plate automatic gauge control (AGC) system using high precision high frequency response of digital hydraulic cylinder as its core transmission control unit, not only have a high accuracy, response speed is much higher than the current using servo valve control system, which reflects the high hydraulic stiffness, strong guarantees the strip thickness accuracy index. Control algorithm can not only improve the stability of the algorithm through the multi model compound feed forward, but also through the Logic Fuzzy to control the ability to adapt to the stronger and better robustness. The system also has the ability of large data acquisition network communications, can be based on large data prediction analysis algorithm, and constantly optimize the software model, so that the level of intelligent system is far more than the existing steel rolling equipment. Predictive analysis algorithm can also be informed in advance of the important equipment maintenance basis, the fault treatment will be stopped before the occurrence of further enhance the operating rate of the rolling mill.
AEMETEC digital hydraulic cold rolled plate automatic gauge control (AGC) system is a huge technical innovation in the field of steel rolling, it is the development of China's steel rolling technology innovation, catch up with foreign advanced technology to bring new opportunities.
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Servo hydraulic AGC
The traditional servo hydraulic cylinder as a regulator of AGC driving device, when the load changes, the closed-loop system composed of servo valve can not provide enough stiffness, change of cylinder position to suppress the load change occurs, so the roll gap must change. So, through the sensor feedback automatic control algorithm to calculate and generate new, adjust the output torque motor to regulate the electrical signal into the servo valve pilot control mechanical quantity, amplified by fluid to push the main valve core control hydraulic cylinder position incremental new, there may be a regulation and can not meet the error correction, so the above process need to disappear until the roll gap error.
Note that the above control is to establish the precise position sensor installed in the hydraulic cylinder under the premise, if only rely on the thickness sensor and the control method needs to be added to the roll from the time lag between the thickness, thus reducing the real-time control system, the effect of adjusting response speed and accuracy.
In order to reduce the gap caused by hysteresis sensor to detect the influence of post, usually according to the different system (metal material, rolling force, frame rigidity) mathematical model, a feedforward control, increasing the system stiffness, improve the control accuracy of AGC.
If the mill roll gap can be fixed in any case, there is no need for AGC. In other words, the role of the rolling mill AGC is adjusted: 1, transmission control hydraulic system position change; 2, rack, roll and other deformation caused by the change of the roll gap, etc..
Digital hydraulic AGC
The control characteristic of the digital hydraulic cylinder is different from the traditional servo hydraulic cylinder. Digital hydraulic cylinder as a regulator of AGC driving device, when the load changes force the cylinder position changes, because the digital cylinder with fast and precise position feedback and adjustment ability of unique, thus the control system which can in the shortest time and the fastest speed, to provide sufficient rigidity of the cylinder to suppress the load caused by the change of position changes, reflecting the changing roll gap is far less than the amount of the servo valve control system, even in most cases, the hydraulic control system of digital control (without < + 1 m) due to the error caused by the load change.
Although the digital hydraulic cylinder greatly suppresses the roll gap error, but because the rolls and the frame will deform and affect the final roll gap, so the control system only through low frequency response with thick thickness error of the sensor, the automatic adjustment algorithm driven digital low frequency response error correction cylinder, complete with thickness control.
Comparison of servo hydraulic and digital hydraulic in AGC application
Compared with the hydraulic system of the cold rolling AGC system, we can see that the hydraulic system's stiffness is different, and the final control response and precision are very different. Digital hydraulic pressure almost does not need to adjust the position of the hydraulic cylinder itself, and only need to adjust the roller frame and the frame deformation.
The system composed of servo hydraulic control requirements, both the complexity of the control algorithm, or sensor, servo valve response and precision is very high. So the overall system comprehensive cost is high.
The system consists of low requirement for digital hydraulic control software, the algorithm is simple, requirements for the frequency response of transducer and hydraulic system is very low, but the high control accuracy of the system, and the comprehensive cost is greatly reduced.