6 Talking about the improvement of the synchronous control method of the double-side hydraulic cylinder of the rolling mill. The synchronous control of the hydraulic system of the reversing mill of the middle plate factory Pan Dejun Zhao Guiqin Xiangshang, directly affecting the same plate difference during sheet rolling, in order to improve the quality of the sheet, in the hydraulic In the control, dynamic synchronization and large-stroke synchronous automatic control are adopted, which can reduce the same plate difference of the sheet during the rolling process.
1 Foreword Hi is the average thickness of the steel plate is the same as the plate and plate shape. Among them, the difference between the steel plate and the plate is related to the roll shape of the roll and the synchronization of the two sides.
The roll shape of the roll is determined according to the production process and the processing technology during the roll processing. Under normal circumstances, the roll shape may change, and the roll shape of the roll changes, from the convex roll to the concave roll. When the roll type changes too much, the problem can be solved by changing the roll so that the lateral plate difference is limited to the required range. However, if the two sides can not be synchronized, the roller type design is reasonable, and the machining accuracy can no longer guarantee that the lateral same plate difference is within the required range. In addition, whether the double side pressing is synchronized or not will affect the average thickness of the steel plate. And the shape of the plate, when the synchronous control is not good, the plate will be bent, so the synchronization of the double-side pressing when the rolling mill is pressed is an important aspect in the rolling mill control. The synchronous control of the pressing system is divided into dynamic synchronization and large stroke synchronization; the former is to ensure the steel plate is inclined and to ensure the synchronization when biting steel.
2 Condition before the transformation The 2500-roll reversing mill of our factory was completed and put into operation in 1994. The original design has an electro-hydraulic reduction system. In order to improve the quality of the plate and reduce the lateral difference, the system is equipped with dynamic synchronization adjustment function. The specific implementation is as follows: the positive and negative directions are determined by the position deviation signals on both the working side and the transmission side, and the hydraulic cylinder position given signals on the working side transmission side are respectively corrected in the opposite direction, so that the side with a fast response speed is slowed down. The speed of the side-lifting speed is slow, that is, the current of the corresponding valve is adjusted, so as to adjust the flow rate of the hydraulic cylinders on both sides, so that the positions of the hydraulic cylinders on both sides are filled with oil at the same speed as possible, so as to ensure the hydraulic cylinders on both sides of the rolling mill. The roll gap is in the same control flow 1.
It is only when the deviation is in the same direction that the dynamic compensation adjustment is performed. If the side deviation is greater than zero and the other side deviation is less than zero, if the correction is still performed according to this method, the result may be counterproductive, that is, the faster the faster side, the slower the speed. Slow, the gap between the two sides of the roll is getting bigger and bigger, and it is easy to produce a sickle bend, and vice versa. In addition, an oscillation phenomenon is generated, which reduces the response speed of the system, so the compensation is not perfect, and complete dynamic synchronization adjustment cannot be achieved. For the synchronous control of the large trip, the original system is not set.
The difference between the working side roll gap and the drive side roll gap is called the roll gap difference, and can be divided into dynamic roll gap difference and static roll gap difference from the mechanism of generation. The dynamic synchronization control of the depressed system is precisely for control. 17.
Set to reduce the dynamic roll gap. Reimbursement, the following improvement scheme is proposed for the original synchronous control method, 3 the control method of reducing the double-side roll gap difference and its synchronous automatic control working principle 2.
In order to fully synchronize the hydraulic pressure control system in order to achieve dynamic synchronization control, reduce the dynamic roller gap difference, plus cross negative feedback control. After the difference of the roll gap values ​​on both sides, the synchronous controller outputs the control amount, and acts in the negative direction on the working side to act on the transmission side in the positive direction. This is a multi-input multi-output control system for the entire control system. For synchronous control, a closed loop control system is formed. Therefore, it has the advantages and disadvantages of the feedback control system.
When the large-stroke synchronous controller is working, the system is in a saturated state. At this time, the saturation value of both sides is adjusted in real time by intelligent means to ensure the synchronization performance index.
The sync controller in the system automatically tests and records both sides 45! And the movement speed of both sides and record the control signals on both sides and the corresponding speed of the movement speed VW, VD, and then use the following control amount for system control, where 7W is the working side control amount, JD is the transmission side control amount, is the control amount The maximum value, that is, the control saturation value of the system, 457 is based on the synchronization deviation of the system. 51 The control amount calculated by using a suitable control algorithm is currently used. The control 7, and the horn are respectively the working side and the transmission side according to the hydraulic cylinder. The speed of movement can be obtained from the above two types. In order to reduce the gap difference during large stroke and ensure the stable operation of the system, the original servo valve current limit value is changed to software proportional adjustment, so that the servo valve is always Work in a linear range. For this purpose, two output control coefficient scales and rulers are set to adjust the servo valve currents on the working side and the transmission side respectively. The servo valve current that is originally output is 0, and after the adjustment, the output becomes the ruler. The current time is set. The roll gap 5 is the actual roll gap.
Use the corpse to find the two-sided control output signal at the current time and 1.
The actual amount of control.
4 Conclusions In the general control method, at the beginning or stop of the work, or a large timing, due to the large deviation, under the action of the integral term, a large overshoot will occur, and its control output It is calculated based on the error, there is a difference control, and no difference control can be realized, although its steady state can achieve no error. For the synchronous control of the rolling mill press, it happens exactly when the quantitative change is given. The purpose is to require no large errors in the dynamic process. Actually, after the method is controlled, the maximum roll gap difference is reduced from 0.3 to 0.03 when the original roll is still adjusted, and the oscillation problem generated when the original corpus control algorithm adjusts the synchronization error is avoided.
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