WO2022083263A1

WO2022083263A1 - Roller table aluminum pickup control method based on micro torque of driving roller

Info

Publication number: WO2022083263A1
Application number: PCT/CN2021/114033
Authority: WO
Inventors: 何安瑞; 于海军; 刘超; 孙文权; 邵健; 王晓晨; 张飞
Original assignee: 北京科技大学
Priority date: 2020-10-22
Filing date: 2021-08-23
Publication date: 2022-04-28
Also published as: CN112453056B; CN112453056A

Abstract

A roller table aluminum pickup control method based on micro torque of a driving roller, the method comprising: selecting, in areas near to two sides of a rolling mill, a driving roller separately driven by an individual electric motor to serve as an experimental roller; conducting an experiment on the driving roller, and selecting, according to an on-site roller table situation, a set of transfer roller tables as roller tables to be corrected; in a system, modifying a driving roller speed control mode during the rolling process, and retrieving process data of normal production; and when speed mismatching occurs between a rolled piece and the transfer roller table, correcting a set speed value of the transfer roller table or a drive mode of the transfer roller table. By means of the method, the speed control mode of a driving roller during the rolling process is modified, and the speed of the driving roller is compared with the speed of a transfer roller table to be corrected, so as to verify the speed matching between a rolled piece and said transfer roller table, and the speed of said transfer roller table is corrected, such that the number of defects, i.e. roller table aluminum pickup and scrapes and scratches on the surface of a rolled piece, which are caused by speed mismatching between the rolled piece and a transfer roller table, can be reduced.

Description

A kind of control method of roller table aluminum sticking based on transmission roller micro-torque

technical field

The invention relates to the technical field of non-ferrous metal rolling, in particular to a method for controlling aluminum sticking on a roller table based on the micro-torque of a transmission roller.

Background technique

In the production process of hot rolling of aluminum sheet and strip, the problem of sticking aluminum on the roller table and affecting the surface quality often occurs. The reason is that the transfer of the rolling stock is mainly completed by the transfer roller table, and the transfer roller table is composed of many driving rollers. Each motor can drive a single driving roller or a group of driving rollers. Roller. The motor that drives the conveying roller table generally adopts the frequency conversion speed regulation system, which mainly includes two control modes, namely the speed loop control mode and the torque loop control mode. In the aluminum strip rolling, the driving motor is generally controlled by the speed loop. At this time, the motor is closed-loop controlled at the actual set speed, and the drive roller is driven to rotate at a certain speed through the deceleration system, so as to achieve the purpose of conveying the rolling stock. However, there is a big difference between the drive motor of the rolling mill and the drive motor of the transfer roller table in the aluminum strip rolling, and when the speed control accuracy of the transfer roller table is not high, it cannot be guaranteed that the linear speed of the transfer roller table and the speed of the rolling piece during the rolling process are completely different. Consistent. When there is a speed difference between the two, there will be relative sliding between the rolling stock and the transfer roller table, resulting in the surface quality defect of the rolling stock being scratched.

In order to improve the surface defects caused by the speed difference between the rolling stock and the transfer roller table, it is necessary to study the matching of the speed of the transfer roller table and the rolling stock speed, and then correct the speed of the transfer roller table to eliminate the difference between the rolling stock and the rolling table. The speed of the transfer rollers is poor, thereby improving the surface quality defects of the rolling stock. In order to improve the surface quality defects caused by the relative sliding between the rolling stock and the conveying roller table, many scholars have carried out research. Document 1 (Setting method of roller table speed of continuous rolling production line, Basic Automation, 1999, Vol. 6, No. 4) proposes a new roller table speed setting method. By optimizing the setting of the frequency converter speed and the motor stator frequency, the relative sliding between the roller table and the bar can be avoided and the surface quality of the bar can be improved. Document 2 (frictionless alignment roller table for cooling bed, authorized patent, CN203842928U) provides a frictionless alignment roller table for cold rolling, which can align the head of the bar on the cooling bed and ensure that there is no relative movement between the rolling stock and the transfer roller table , to avoid friction marks on the surface of the bar. Document 3 (a method to prevent the tail of the strip from rising before the coiler, authorized patent, CN103521554B) by increasing the amount of water in the upper header for laminar flow cooling, and using the downward momentum of the water flow to enhance the fit between the strip and the roller table By increasing the friction between the roller table and the strip, the synchronization between the two is increased, avoiding the occurrence of asynchrony in the deceleration of the transmission roller transmission equipment, and reducing the thin strip tail before the coiler. The occurrence of scratches improves product quality and yield. It can be seen from the above literature that improving the speed matching between the rolling stock and the transfer roller table is an important means to improve the surface quality of the rolling stock. Therefore, find a simple and feasible method to test the speed matching of the rolling stock and the transfer roller table, and then pass the test. It is of great significance to improve the surface quality of the aluminum strip by correcting the speed of the conveying roller to improve the matching of the rolling stock and the speed of the conveying roller.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a roller table sticking control method based on the micro-torque of the transmission roller, to test the matching of the speed of the rolling piece and the speed of the conveying roller table in the hot rolling of aluminum strips, and based on this, the The speed of the conveying roller table is corrected to reduce the relative sliding between the rolling stock and the conveying roller table to improve the scratch defect on the surface of the rolling stock, thereby improving the surface quality of the aluminum strip.

The method first selects a drive roll independently driven by a single motor as the test roll in the vicinity of both sides of the rolling mill; then conducts experiments on the drive roll, modifies the drive motor control mode of the drive roll to the torque loop control mode and applies the drive torque M, In order to make the drive roller in a critical state from stationary to starting to rotate; then select a group of conveying rollers as the rollers to be corrected according to the situation of the on-site rollers; then modify the speed control mode of the driving rollers during the rolling process in the system, starting with the rolling stock Biting into the rolling mill is the signal, and the control mode of the drive roll is switched from the speed loop control to the torque loop control; then the process data of normal production is retrieved, and the speed of the rolling mill, the speed of the drive roll and the speed of the conveying roll table to be corrected are analyzed to obtain the rolling mill speed. The matching situation between the speed of the piece and the speed of the conveying roller table to be corrected; finally, for the situation that the speed of the rolling piece and the conveying roller table do not match, correct the setting value of the speed of the conveying roller table or the driving mode of the conveying roller table, by increasing the speed of the rolling mill and the conveying roller table. Matching can reduce the sticking of aluminum on the roller table and improve the surface quality of aluminum strip rolling.

The specific steps are as follows:

(1) Select a drive roll independently driven by a single motor as the test roll in the vicinity of both sides of the rolling mill. The drive roll is as close as possible to the roll gap of the rolling mill to ensure that the rolling piece is in normal contact with the drive roll and has as much contact time as possible;

(2) Set the drive motor control mode of the drive roller to torque loop control mode, apply the drive torque M to make the drive roller in a critical state from static to starting to rotate, record the torque value, and then control the drive roller drive motor The mode is set to speed loop control mode;

(3) Select a group of conveying rollers as the conveying rollers to be corrected, and the drive motor control mode of the conveying rollers is the speed loop control mode;

(4) Modify the control program of the drive motor of the drive roller during the rolling process, and switch the control mode of the drive motor of the drive roller from the speed loop to the torque loop with the signal that the rolling piece is bitten into the rolling mill, and the torque value is M, and then use When the rolling stock exits the rolling mill as a signal, the control mode of the drive motor of the drive roller is switched from the torque loop to the speed loop;

(5) In normal production, the drive roll is driven to rotate by the rolling piece, and its linear speed will be the same as the rolling piece speed. The production process data is retrieved, and the speed of the rolling mill, the speed of the drive roll and the speed of the conveying roller table to be corrected are analyzed. The speed value and speed change of the roller and the transfer table to be corrected to verify the matching of the rolling stock and the speed of the transfer table to be corrected;

(6) When the speed of the rolling stock does not match the speed of the conveying roller table, the speed matching between the rolling stock and the conveying roller table can be improved by correcting the set value of the speed of the conveying roller table or the driving mode of the conveying roller table, thereby reducing the sticking of aluminum on the roller table. To improve the surface quality of aluminum strip rolling.

Wherein, when the drive roll is selected as the test roll in step (1), one drive roll is selected on one side of the rolling mill or one drive roll is selected on both sides of the rolling mill; the selected drive roll is as close as possible to the roll gap of the rolling mill to ensure the rolling The workpiece is in normal contact with the drive roll and has as much contact time as possible. If there is no suitable drive roll near the rolling mill but the length of the rolling piece is long enough, select the drive roll with a slightly farther distance as the test roll; the selected drive roll is driven by a single motor, It is beneficial to switch the speed control mode of the drive roller and improve the accuracy of the feedback value of the speed of the drive roller.

In step (2), when experimenting on the transmission roller, the control mode of the transmission roller drive motor is modified to the torque loop mode, and the rotational inertia of the transmission roller itself, the friction coefficient of the bearings at both ends of the transmission roller, and the transmission efficiency of the motor are considered to set the driving motor of the transmission roller. Torque value M, under the action of this torque value, the transmission roller is in a critical state from stationary to starting to rotate, that is, the transmission roller is stationary after applying torque M, but after contacting with the moving rolling piece, the driving roller follows the rolling piece at the same speed. Linear speed rotation; after determining the value of torque M, set the drive roller drive motor control mode to speed loop mode.

In step (3), when a group of conveying rollers are selected as the conveying rollers to be corrected, the conveying rollers with severe wear or aluminum sticking are selected as the rollers to be corrected according to the on-site conditions, so as to verify that the speed of the conveying rollers matches the rolling stock. Condition.

In step (4), the rolling stock is bitten into the rolling mill as a signal, the control mode of the drive motor of the drive roller is switched from the speed loop to the torque loop, and the torque value is the torque value M obtained in step (2), and then Then take the rolling stock out of the rolling mill as the signal, switch the control mode of the drive motor of the drive roller from the torque loop to the speed loop, that is, keep the control mode of the drive roller motor as the torque loop during the rolling process, and drive the drive before and after the rolling is completed. The roller motor control mode is speed loop.

In step (5), after the rolling is completed, the production process data is retrieved, and the speed of the rolling mill, the speed of the transmission roller and the speed of the transmission roller table to be corrected and the speed change are analyzed, wherein the speed of the transmission roller and the speed of the transmission roller table to be corrected are determined by The system is calculated by the motor feedback current value.

In step (6), since the transmission roller is driven and rotated by the rolling piece, the linear speed of the driving roll is the same as the rolling piece speed. The set value of the roller table speed or the drive mode of the transfer roller table can reduce the sticking of aluminum on the roller table and improve the surface quality of the aluminum strip by improving the speed matching of the rolling stock and the transfer roller table.

The beneficial effects of the above-mentioned technical solutions of the present invention are as follows:

1. The present invention is based on the roller table sticking control method of the micro-torque of the transmission roller. The normal transmission roller table on both sides of the rolling mill is selected as the test roller, and the control mode is switched from the speed loop to the torque loop according to the rolling start signal. The implementation process Only need to modify the speed control mode of the drive roller without adding new equipment;

2. The present invention is based on the micro-torque driving roller micro-torque control method of the roller table sticking to aluminum, which can detect the speed matching of the conveying rollers in different areas according to the situation of the conveying rollers on site;

3. The present invention is based on the micro-torque of the transmission roller to control the aluminum sticking on the roller table. By detecting the matching of the speed of the conveying roller table in different areas and the speed of the rolling piece, and correcting the speed of the conveying roller table in different areas, the conveying roller table can be improved. Matching with the speed of the rolling piece, reduce the sticking of aluminum on the roller table, and improve the surface quality of the rolling piece.

Description of drawings

Fig. 1 is the implementation flow chart of the conveying roller table speed correction method of the present invention;

Fig. 2 is the relative position diagram of the drive roll on the right side of the roll gap of the rolling mill of the present invention and the rolling mill;

Fig. 3 is the relative position diagram of the transfer roller table to be corrected and the rolling mill of the present invention;

FIG. 4 is a graph showing the production data of a certain pass in the experimental process of the present invention.

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

The invention provides a method for controlling aluminum sticking on a roller table based on the micro-torque of a transmission roller.

In this method, the drive roll independently driven by a single motor is selected as the experimental roll in the vicinity of both sides of the rolling mill; then the experiment is carried out on the drive roll, and the control mode of the drive motor of the drive roll is modified to the torque loop control mode and the driving torque M is applied, In order to make the drive roller in a critical state from stationary to starting to rotate; then select a group of conveying rollers as the rollers to be corrected according to the situation of the on-site rollers; then modify the speed control mode of the driving rollers during the rolling process in the system, starting with the rolling stock Biting into the rolling mill is the signal, and the control mode of the drive roll is switched from the speed loop control to the torque loop control; then the process data of normal production is retrieved, and the speed of the rolling mill, the speed of the drive roll and the speed of the conveying roll table to be corrected are analyzed to obtain the rolling mill speed. The matching situation between the speed of the piece and the speed of the conveying roller table to be corrected; finally, for the situation that the speed of the rolling piece and the conveying roller table do not match, correct the setting value of the speed of the conveying roller table or the driving mode of the conveying roller table, by increasing the speed of the rolling mill and the conveying roller table. Matching can reduce the sticking of aluminum on the roller table and improve the surface quality of aluminum strip rolling.

The implementation process of the method is shown in Figure 1, and the specific steps are as follows:

(1) Select a drive roll independently driven by a single motor as the test roll in the vicinity of both sides of the rolling mill. The drive roll should be as close as possible to the roll gap of the rolling mill to ensure normal contact between the rolling piece and the drive roll and have as much contact time as possible. ;

(5) In normal production, the drive roll is driven to rotate by the rolling piece, and its linear speed is the same as the rolling piece speed. The production process data is retrieved, and the speed of the rolling mill, the speed of the drive roll and the speed of the conveying roller table to be corrected are analyzed. By comparing the drive roll Verify the matching of the rolling stock and the speed of the transfer roller table to be corrected with the speed value and speed change of the transfer roller table to be corrected;

In step (2), the control mode of the drive motor of the drive roller is modified to the torque loop mode when the drive roller is tested, and the drive motor of the drive roller is set considering the rotational inertia of the drive roller, the friction coefficient of the bearings at both ends of the drive roller, and the transmission efficiency of the motor. The torque value M, under the action of this torque value, the drive roller is in a critical state from stationary to starting to rotate, that is, the drive roller is stationary after the torque M is applied, but after contact with the moving rolling piece, the driving roller follows the rolling piece at the same speed. After determining the value of torque M, set the drive roller drive motor control mode to speed loop mode.

In step (3), when a group of conveying rollers is selected as the conveying rollers to be corrected, the conveying rollers with severe wear or aluminum sticking are selected as the rollers to be corrected according to the site conditions, so as to verify the speed of the conveying rollers and the rolling stock. match.

In step (4), with the rolling piece being bitten into the rolling mill as a signal, the control mode of the drive motor of the drive roller is switched from the speed loop to the torque loop, and the torque value is the torque value M obtained in step (2), Then use the rolling stock out of the rolling mill as the signal to switch the control mode of the drive motor of the drive roller from the torque loop to the speed loop, that is, keep the control mode of the drive roller motor as the torque loop during the rolling process, before rolling and after the rolling is completed. The control mode of the drive roller motor is speed loop.

In step (5), after the rolling is completed, the production process data is retrieved, and the speed of the rolling mill, the speed of the transmission roller and the speed of the transmission roller table to be corrected are analyzed, wherein the speed of the transmission roller and the transmission roller table to be corrected are all fed back by the system through the motor The current value is calculated.

In step (6), since the transmission roller is driven and rotated by the rolling piece, the linear speed of the driving roll is consistent with the rolling piece speed. The setting value of the speed of the transfer roller table or the drive mode of the transfer roller table can reduce the sticking of aluminum on the roller table and improve the surface quality of the aluminum strip by improving the speed matching of the rolling stock and the transfer roller table.

The following description will be given in conjunction with specific embodiments.

Example 1

Step (1): The drive roll as the test roll should be as close as possible to the roll gap of the rolling mill to ensure normal contact between the rolling stock and the drive roll and have as much contact time as possible; the selected drive roll should be driven by a single motor, which It is beneficial to switch the speed control mode of the drive roll and improve the accuracy of the speed feedback value of the drive roll; in this embodiment, a drive roll on the right side of the roll gap of the rolling mill is selected as the experimental roll. The motor is driven independently, and its relative position to the rolling mill is shown in Figure 2.

Step (2): Experiment on the drive roller, change its drive motor control mode to torque loop mode, and drive the drive roller motor to rotate after considering the influence of its own moment of inertia, friction coefficient of the bearings at both ends, and motor transmission efficiency. The torque value M is set to ±3.75kN m. Under the action of this torque value, the transmission roller remains stationary, and the transmission roller starts to rotate after artificially applying a small torque. It can be seen that under the action of this torque, when After the rolling stock comes into contact with the drive roll, the drive roll will start to rotate and its linear speed will be equal to the rolling stock speed.

Step (3): A group of transfer rollers under the coiler on the right side of the rolling mill contains a total of 12 drive rollers, which are driven by a motor through a chain drive. During production, this group of transfer rollers has serious aluminum sticking and will The surface of the hot-rolled aluminum strip is scratched and scratched, so this group of transfer rollers is selected as the transfer roller table to be corrected, and its relative position to the rolling mill is shown in Figure 3.

Step (4): In the rolling experiment, the control mode of the drive motor of the drive roll needs to be switched from the speed loop to the torque loop. In order to switch the speed control mode to the torque loop before the rolling stock reaches the drive roll, it is necessary to switch the drive roll to the torque loop in advance. The control mode of the drive motor is switched, so the rolling force curve is used as the signal. When the rolling force changes from no time, the speed control mode of the transmission roller is switched from the speed loop to the torque loop. When the rolling stock is out of the rolling mill, the rolling force curve becomes 0, at this time, the control mode of the drive motor of the drive roller is switched from the torque loop to the speed loop.

Step (5): Roll normally until the entire rolling process is completed, retrieve the production process data, and analyze the speed values and speed changes of the rolling mill, the drive roller and the transfer roller table to be corrected, and the speed curve is shown in Figure 4 .

It can be seen from Figure 4 that the rolling speed decreases, and the speed of the transmission roller (the "right deflection guide roller" in the figure) and the transmission roller table to be corrected (the "work roller table (3)" in the figure) also decreases. Obvious deceleration section and stable section, the change trend is obvious. The speed of the transmission roller and the conveying roller to be corrected are calculated by the current value fed back by the motor, and the linear speed value can be calculated by the reduction ratio of the driving motor and the conveying roller and the diameter of the conveying roller. Table 1 shows the speed changes of the rolling mill, the drive roller and the transfer roller table to be corrected in the experiment.

Table 1 Speed variation of a certain pass in the rolling process

There is forward slippage during the rolling process, and the speed of the rolling stock is greater than the speed of the rolling mill. During the experiment, the driving roller is driven to rotate by the rolling stock, and its linear speed is consistent with the speed of the rolling stock, so the speed of the driving roller is greater than the speed of the rolling mill; The speed of the conveying roller table is calculated by the feedback current of the driving motor. The existence of feedback error causes a certain deviation between the speed of the transmission roller and the speed of the conveying roller table to be corrected, but the deviation is small, indicating that the rolling process of this pass is different from the one to be corrected. Correct the speed of the conveying rollers to be consistent and match.

Through further research, it is found that when the load is heavy, the conveyor roller table to be corrected will slip. This is because all 12 drive rollers of the conveyor roller table to be corrected are driven by one motor, and this motor is connected with the other two motors. It is jointly controlled by a frequency converter. When there are too many conveying rollers controlled by the frequency converter, the output torque of some motors will be too small, which will cause the transmission roller to be corrected to slip when conveying thick rolled pieces, resulting in serious roller adhesion. Aluminium phenomenon. At this time, simply modifying the speed setting value of the conveying roller table in step (6) will not be able to improve the speed matching between the rolling stock and the conveying roller table. The motor is independently controlled by a frequency converter, and the serious aluminum sticking problem caused by the mismatch between the speed of the transfer roller to be corrected and the rolling piece can be improved by improving the output torque accuracy of the drive motor.

Of course, the above selection of the transmission roller and the transmission roller table to be corrected is only an example, not a limitation. Under the condition that the above experimental conditions are met, the better the contact between the transmission roller and the rolling piece, the better the transmission roller and the transmission roller table to be corrected. The higher the accuracy of the current feedback value, the higher the accuracy of the experiment will be, and it will be more beneficial to the correction of the speed of the conveying roller table and the improvement of the surface quality defects of the rolling piece.

The above are the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims

A method for controlling aluminum sticking on a roller table based on the micro-torque of a transmission roller, characterized in that: the method comprises the following steps:

(1) Select a drive roll independently driven by a single motor as the test roll in the vicinity of both sides of the rolling mill. The drive roll is as close as possible to the roll gap of the rolling mill to ensure that the rolling piece is in normal contact with the drive roll and has as much contact time as possible;

(2) Set the drive motor control mode of the drive roller to torque loop mode, apply the drive torque M to make the drive roller in a critical state from static to starting to rotate, record the torque value, and then drive the drive roller to the motor control mode Set to speed loop control mode;

(3) Select a group of conveying rollers as the conveying rollers to be corrected, and the drive motor control mode of the conveying rollers is the speed loop control mode;

(4) Modify the control program of the drive roller drive motor in the rolling process, and switch the drive roller drive motor control mode from the speed loop control mode to the torque loop control mode with the rolling piece being bitten into the rolling mill as a signal, and the torque value is M , and then use the rolling stock out of the rolling mill as a signal to switch the control mode of the drive motor of the drive roller from the torque loop control mode to the speed loop control mode;

(5) During the test, the drive roll is driven to rotate by the rolling piece, and its linear speed will be the same as the rolling piece speed. The production process data is retrieved, and the speed of the rolling mill, the speed of the drive roll and the speed of the conveying roller table to be corrected are analyzed. When it is consistent with the speed value and speed change of the transfer roller table to be corrected, it means that the speed of the rolling stock and the transfer roller table to be corrected match well. The speed does not match, so as to verify the matching of the rolling stock and the speed of the transfer roller table to be corrected;

(6) When the speed of the rolling stock does not match the speed of the conveying roller table, the speed control accuracy of the conveying roller table can be improved by correcting the setting value of the conveying roller table speed or the driving mode of the conveying roller table, thereby improving the speed of the rolling stock and the conveying roller table. Consistency and matching, reduce the sticking of aluminum on the roller table, and improve the surface quality of aluminum strip rolling.
The method for controlling aluminum sticking on the roller table based on the micro-torque of the transmission roller according to claim 1, characterized in that: in the step (1), the test roller selects a transmission roller on one side of the rolling mill or selects each on both sides of the rolling mill One drive roller; the selected drive roller is driven by a single motor.
The method for controlling aluminum sticking on the roller table based on the micro-torque of the transmission roller according to claim 1, characterized in that: in the step (2), the driving torque M can make the transmission roller be in a critical state from stationary to starting to rotate, That is, after applying torque M, the transmission roller is stationary, but after contacting with the moving rolling stock, the driving roller rotates at the same linear speed following the rolling stock.
The method for controlling aluminum sticking to a roller table based on the micro-torque of the transmission roller according to claim 1, characterized in that: the transfer roller table to be corrected in the step (3) is a transfer roller table that is worn or seriously adhered to aluminum.
The method for controlling aluminum sticking on the roller table based on the micro-torque of the transmission roller according to claim 1, characterized in that: in the step (4), the control mode of the motor of the transmission roller during the rolling process is kept as torque loop, and before rolling And after the rolling is completed, the control mode of the drive roller motor is the speed loop.
The method for controlling aluminum sticking on a roller table based on the micro-torque of the transmission roller according to claim 1, characterized in that: in the step (5), the speed of the transmission roller and the speed of the conveying roller table to be corrected are both fed back by the current value of the system through the motor Calculated.