JP7501451B2 - Meandering control device - Google Patents

Description

The present invention relates to a meandering control device.

In continuous rolling mills equipped with multiple rolling stands, such as hot finishing mills, a meandering phenomenon is known in which the widthwise center of the material being rolled (rolled material) shifts from the widthwise center of the rolling rolls and moves toward the working side or drive side of the continuous rolling mill.

In a continuous rolling mill, when the rolled material passes through any rolling stand, it is rolled by the rolling stand one step downstream, and the rear tension at the tail end is eliminated. At this time, the tail end of the rolled material rotates due to the difference in elongation between the left and right (work side and drive side) at the entrance to the rolling stand, and moves in the width direction just below the rolling roll, causing a meandering phenomenon at the tail end.

Directly below the rolling rolls, the load on the side where the rolled material is meandering increases, causing the elastic deformation of the rolling mill on that side to increase, opening up the gap between the rolling rolls on that side and making the plate thicker. As a result, the difference in elongation between the left and right sides of the rolled material increases, further promoting the meandering.

At the exit of the rolling stand, the meandering rolled material curves and enters the downstream rolling stand. In a continuous rolling mill, the meandering phenomenon can occur at each rolling stand, and the meandering can progress rapidly. When the tail end of the meandering rolled material collides with the side guide installed at the entry side of the rolling stand, it bends and is rolled in this state, causing squeezing. Squeezing can damage the rolling rolls and require work to be stopped, such as for roll replacement, reducing production efficiency.

Conventional meandering control technologies for rolling mills can be broadly divided into two types: methods that dynamically control roll leveling based on the rolling differential load or the amount of meandering detected by a camera installed between the rolling stands, and methods that preset roll leveling based on past rolling results.

The most common method for dynamically controlling roll leveling has been to use the rolling differential load in the past, and in recent years to detect or estimate meandering using a camera installed between the stands, and to control roll leveling through feedback calculations.

For example, Patent Document 1 proposes a method that uses an optimal regulator to estimate the meandering amount and entry angle of the rolled material using a state observer based on the rolling differential load, and controls the roll leveling so as to minimize an evaluation function whose variables are the meandering amount, the integral of the meandering amount, the entry angle, and the roll leveling.

In addition, the difference in elongation between the left and right sides of the rolled material that causes meandering is caused by changes in the wedge ratio between the entry and exit sides of the rolling stand (the difference in plate thickness between the working side and the drive side is called the wedge, and the wedge divided by the plate thickness is called the wedge ratio), so a control method has been proposed that focuses on changes in the wedge ratio to suppress meandering.

For example, Patent Document 2 proposes a method of measuring the wedge at the exit of the final rolling stand, and controlling the roll reduction leveling for each rolling stand so that it is equal to the measured wedge ratio, thereby reducing the wedge and suppressing meandering.

As a method for setting the roll leveling in advance, for example, Patent Document 3 proposes a method in which the roll leveling correction amount for each rolling stand is calculated for the material in question (the rolled material for which the roll leveling is set) and the preceding material (the rolled material rolled immediately before) based on the relationship between the roll leveling and camber amount (the amount of curvature of the body relative to the leading and trailing ends is called the camber amount) of each rolling stand, and the roll leveling is set based on the difference.

Japanese Patent No. 5790636 Patent No. 6044194 Japanese Patent No. 3664068

In the method described in Patent Document 1, the rolled material is rotated in a direction that reduces meandering by changing the exit wedge and changing the wedge ratio during roll leveling.

However, the changed exit wedge is the entry wedge as seen from the rolling stand one step downstream. When the rolling stand one step downstream rolls the rolled material, it causes a rotation in the direction that restores the reduced meandering.

Therefore, unless the influence from the upstream rolling stand or the influence on the downstream rolling stand is taken into consideration, meandering control of the entire rolling stand can become unstable.

In addition, in the method described in Patent Document 2, if the wedge ratio is not uniform in the longitudinal direction of the rolled material, the wedge ratio measured at the exit side of the final rolling stand differs from the wedge ratio of the rolled material located immediately below the rolling rolls of each rolling stand, and therefore effective control may not be possible.

Focusing on the tail end of the rolled material, meandering cannot be prevented because the time to stabilize through feedback control or the length of the rolled material is insufficient. In addition, since the wedge ratio is the ratio of plate thickness to wedge, large reduction leveling is required in the upstream rolling stand where the plate thickness is thick. In such cases, due to mechanical constraints of the equipment, the reduction leveling cannot be controlled sufficiently and the target wedge ratio cannot be achieved. As a result, there is a risk that the wedge ratio will not match that of the downstream rolling stand, causing meandering.

In addition, in the method described in Patent Document 3, the roll leveling of each rolling stand is determined independently with respect to the camber amount, and the influence of the upstream rolling stand on the downstream rolling stand cannot be taken into consideration. In addition, in the meandering phenomenon at the tail end, the meandering develops exponentially with respect to time or rolling distance, and the meandering and wedges interfere with each rolling stand.

For more accurate prediction, it is desirable to use a rolling model to explicitly determine the meandering and wedge after rolling for each rolling stand and to simulate their evolution with time or rolling distance.

In addition, the above-mentioned conventional technology does not have a means to automatically correct the model used or the table of influence coefficients between variables based on the rolling results, so there is a risk that it will not be able to respond to changes over time and it will be necessary to repeatedly adjust the model manually.

The present invention has been made to solve the above-mentioned problems, and aims to provide a meandering control device that can control the rolling mill to achieve stable sheet threading while maintaining wedge quality, even when the continuous rolling mill is continuously rolling the material.

The meandering control device according to one aspect of the present invention is a meandering control device that controls the meandering of a material by a continuous rolling mill having multiple rolling stands that sequentially apply a rolling force as the material passes through the mill, and is characterized by having a prediction calculation unit that predicts the meandering amount and wedge amount of each of the material tail ends after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands that uses rolling information that specifies the initial meandering amount of the material before rolling, the final meandering amount of the material rolled by all of the rolling stands, the roll-down leveling set values for each of the multiple rolling stands, and the setting of the rolling process, a setting value update unit that updates the roll-down leveling set values for each of the multiple rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit, and a plurality of roll-down leveling control units that control the roll-down leveling of each of the multiple rolling stands based on the roll-down leveling set values updated by the setting value update unit.

In addition, the meandering control device according to one aspect of the present invention is preferably characterized in that the set value update unit updates the roll leveling set value for each of the plurality of rolling stands by repeating evaluation using an evaluation function based on the meandering amount and wedge amount predicted by the prediction calculation unit until a predetermined termination condition is satisfied so that the roll leveling set value for each of the plurality of rolling stands becomes a time-series or rolling distance series roll leveling set pattern, and the roll leveling control unit controls the roll leveling of the rolling stands based on the roll leveling set pattern, time, and material inlet speed updated by the set value update unit.

In addition, the meandering control device according to one aspect of the present invention is preferably characterized in that the set value update unit updates the roll leveling set value for each of the multiple rolling stands by repeating evaluation using an evaluation function based on the meandering amount and wedge amount predicted by the prediction calculation unit until a predetermined termination condition is met, while keeping the roll leveling set value constant.

The meandering control device according to one aspect of the present invention is preferably characterized in that the set value update unit updates the roll-down leveling set value for each of the multiple rolling stands, in order from the upstream side, so that the meandering amount of a predetermined point of the tail end of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit becomes zero.

In addition, the meandering control device according to one aspect of the present invention is preferably characterized in that the set value update unit performs an evaluation using an evaluation function based on the meandering amount and wedge amount of a predetermined point of the tail end of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit for each of the multiple rolling stands, starting from the upstream side, until a predetermined end condition is satisfied, and updates the roll down leveling set value for each of the multiple rolling stands based on the evaluation result.

In addition, the meandering control device according to one aspect of the present invention preferably further includes a learning value storage unit that stores learning values used to adjust the rolling model, and a learning value update unit that updates the learning values stored in the learning value storage unit, and the multiple roll gap leveling control units acquire roll gap leveling performance patterns of time series or rolling distance series from the multiple rolling stands, respectively, and the prediction calculation unit predicts the meandering amount and wedge amount of each of the material tail ends after passing through each of the multiple rolling stands based on the rolling models of each of the multiple rolling stands using the initial meandering amount, the final meandering amount, each of the roll gap leveling performance patterns acquired by the multiple roll gap leveling control units, the rolling information, and the learning values stored in the learning value storage unit, and the learning value update unit updates the learning values stored in the learning value storage unit using the meandering amount of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit and the final meandering amount.

The meandering control device according to one aspect of the present invention is preferably characterized in that the learning value update unit repeats evaluation using an evaluation function that uses the meandering amount of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit and the final meandering amount, and updates the learning value for each of the multiple rolling stands until a predetermined termination condition is satisfied.

The meandering control device according to one aspect of the present invention is preferably characterized in that the learning value update unit updates the learning value so that the error between the meandering amount of a given point of the tail end of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit and the final meandering amount becomes zero.

The meandering control device according to one aspect of the present invention is preferably characterized in that the learning value update unit evaluates the meandering amount detected by an inter-stand meandering amount detection unit that detects the meandering amount of the material between the rolling stand and the other rolling stands and the meandering amount predicted by the prediction calculation unit using an evaluation function, and updates the learning value until a predetermined termination condition based on the evaluation result is satisfied.

According to the present invention, even when a continuous rolling mill continuously rolls material, it is possible to control the rolling mill to achieve stable sheet threading while maintaining wedge quality.

FIG. 1 is a side view illustrating a schematic configuration example of a rolling system according to an embodiment. FIG. 1 is a diagram illustrating an example of the configuration of a meandering control device and its peripheral configuration according to an embodiment; 13 is a flowchart showing a process in which the meandering control device performs repeated calculations in a setting step of the first operation example. FIG. 10 is a diagram illustrating a roll-down leveling setting pattern in a first operation example of the meandering control device. 10 is a flowchart showing a process in which the meandering control device performs repeated calculations in a learning step of the first operation example. FIG. 13 is a diagram showing a schematic diagram of a tension state during rolling in a third operation example of the meandering control device. 13A to 13C are diagrams illustrating the characteristics of the rolled material at each position after rolling in the third operation example of the meandering control device. FIG. 13 is a diagram illustrating an example of the configuration of a meandering control device and its peripheral configuration in a modified example of the rolling system. 10 is a flowchart showing a process in which the meandering control device performs repeated calculations in a learning step. 2 is a conceptual diagram showing an example of a hardware configuration of a processing circuit included in the meandering control device. FIG.

Below, an embodiment of a rolling system will be described with reference to the drawings. FIG. 1 is a side view showing a schematic configuration example of a rolling system 100 according to one embodiment. As shown in FIG. 1, the rolling system 100 has, for example, a continuous rolling mill 10, a meandering control device 20, and a setup device 30.

The rolling stands _F1 , _F2 , ..., _FN included in the multi-stage continuous rolling mill 10 sequentially pass the rolled material (raw material) 1, and each of them applies a rolling force to the rolled material 1. N is a natural number of 2 or more. That is, the rolled material 1 moves so as to pass through the rolling stands _F1 , _F2 , ..., _FN sequentially (from left to right in FIG. 1 ) and is rolled to a predetermined plate thickness.

Each rolling stand F _i (1≦i≦N) is equipped with two work rolls 11, one above and one below, and two backup rolls 12, one above and one below, and the gap between the upper and lower work rolls 11 can be adjusted by means of reduction devices (not shown) provided on the working side and drive side of the backup rolls 12, respectively.

The roll reduction control unit 13 acquires a roll reduction leveling setting value from the meandering control device 20 and changes the roll reduction leveling by the roll reduction device (the difference between the roll reduction amount on the work side and the drive side) to the acquired roll reduction leveling setting value. The roll reduction control unit 13 also outputs the actual roll reduction leveling by the roll reduction device to the meandering control device 20 (roll reduction leveling control unit 23 described later) as a time-series or rolling distance-series roll reduction leveling performance pattern.

The initial meandering amount detection unit 2 is installed upstream of the rolling stand _F1 , detects an initial meandering amount, which is the amount of meandering of the rolled material 1 before rolling, and outputs the detected initial meandering amount to the meandering control device 20. For example, the initial meandering amount detection unit 2 detects the deviation of the width direction center position of the rolled material 1 from the width direction center position of the continuous rolling mill 10 as the initial meandering amount.

The final meandering amount detection unit 3 is installed downstream of the rolling stands F to _N , detects the final meandering amount, which is the amount of meandering of the rolled material 1 rolled by all the rolling stands, and outputs the detected final meandering amount to the meandering control device 20. The final meandering amount detection unit 3 detects the deviation of the width direction center position of the rolled material 1 from the width direction center position of the continuous rolling mill 10 as the final meandering amount. Note that the location where the final meandering amount detection unit 3 is installed is not limited to the delivery side of the continuous rolling mill 10, and it may be installed in another downstream process.

The meandering control device 20 calculates the roll-down leveling setting value for each rolling stand based on the rolling information input from the setup device 30, the initial meandering amount input from the initial meandering amount detection unit 2, and the final meandering amount input from the final meandering amount detection unit 3, and outputs it to each of the roll-down control units 13.

Next, an example of the configuration of the meandering control device 20 according to one embodiment will be described. FIG. 2 is a diagram illustrating an example of the configuration of the meandering control device 20 according to one embodiment and its peripheral configuration. Hereinafter, the same reference numerals will be used to designate configurations that are substantially the same as those described above.

The meandering control device 20 includes a prediction calculation unit 21, a set value update unit 22, N pressure reduction leveling control units 23, a learning value update unit 24, and a learning value memory unit 25.

The prediction calculation unit 21 predicts the meandering amount and wedge amount of each of the tail ends of the rolled material 1 after passing through each of the multiple rolling stands based on a rolling model for each of the multiple rolling stands that uses rolling information that specifies the initial meandering amount of the rolled material 1 before rolling, the final meandering amount of the rolled material 1 rolled by all rolling stands, the roll-down leveling setting value for each of the multiple rolling stands, and the settings of the rolling process.

The prediction calculation unit 21 also has a function of predicting the meandering amount and wedge amount of each of the tail ends of the rolled material 1 after passing through each of the multiple rolling stands based on the rolling model of each of the multiple rolling stands using the initial meandering amount, the final meandering amount, each of the roll leveling performance patterns acquired by the multiple roll leveling control units 23, the rolling information, and the learning values stored in the learning value memory unit 25.

The setting value update unit 22 updates the roll leveling setting value for each of the multiple rolling stands based on the meandering amount and wedge amount of each tail end of the rolled material 1 predicted by the prediction calculation unit 21.

The set value update unit 22 also has a function of updating the roll down leveling setting value for each of the multiple rolling stands by repeating evaluation using an evaluation function based on the meandering amount and wedge amount predicted by the prediction calculation unit 21 until a predetermined termination condition is met, so that the roll down leveling setting value for each of the multiple rolling stands becomes a time series or rolling distance series roll down leveling setting pattern.

The set value update unit 22 also has the function of setting the roll down leveling set value to a constant value, repeating evaluation using an evaluation function based on the meandering amount and wedge amount predicted by the prediction calculation unit 21 until a predetermined termination condition is met, and updating the roll down leveling set value for each of the multiple rolling stands.

The setting value update unit 22 also has a function of updating the roll-down leveling setting value for each of the multiple rolling stands, starting from the upstream side, so that the meandering amount of a predetermined point of the tail end of the rolled material 1 after passing through the most downstream rolling stand predicted by the prediction calculation unit 21 becomes zero.

The set value update unit 22 also performs an evaluation using an evaluation function based on the meandering amount and wedge amount of a predetermined point of the tail end of the rolled material 1 after passing through the most downstream rolling stand predicted by the prediction calculation unit 21 for each of the multiple rolling stands, starting from the upstream side, until a predetermined end condition is met, and has the function of updating the roll leveling set value for each of the multiple rolling stands based on the evaluation result.

The roll-down leveling control unit 23 controls the roll-down leveling of each of the multiple rolling stands based on the roll-down leveling setting values updated by the setting value update unit 22.

The roll-down leveling control unit 23 also has the function of controlling the roll-down leveling of the rolling stand based on the roll-down leveling setting pattern, time, and inlet speed of the rolled material 1 updated by the setting value update unit 22.

The learning value update unit 24 updates the learning values used to adjust the rolling model stored in the learning value storage unit 25.

The learning value update unit 24 also has the function of updating the learning value stored in the learning value memory unit 25 using the meandering amount of the rolled material 1 after passing through the most downstream rolling stand predicted by the prediction calculation unit 21 and the final meandering amount.

The learning value update unit 24 also has a function of repeatedly evaluating the amount of meandering of the rolled material 1 after passing through the most downstream rolling stand predicted by the prediction calculation unit 21 and the final meandering amount using an evaluation function, and updating the learning values for each of the multiple rolling stands until a predetermined termination condition is met.

The learning value update unit 24 also has the function of updating the learning value so that the error between the meandering amount at a specified point of the tail end of the rolled material 1 after passing through the most downstream rolling stand predicted by the prediction calculation unit 21 and the final meandering amount becomes zero.

Next, the functions and operations of each part of the meandering control device 20 will be described in detail. The operation of the meandering control device 20 includes a setting step, a control step, and a learning step.

In the setting step, the meandering control device 20 starts operating after the tail end of the rolled material 1 passes through the initial meandering amount detection unit 2, and the setting value update unit 22 calculates the roll down leveling setting value and outputs the calculation result to the roll down leveling control unit 23, thereby completing the operation.

In the control step, the meandering control device 20 controls each rolling stand at different times.

For example, the leveling control unit 23 corresponding to the rolling stand _F1 starts operation after the position at a distance Lt from the tail end of the rolled material 1 passes directly below the work rolls 11 of the rolling stand _F1 . Then, the leveling control unit 23 operates (controls) the leveling control unit 13 according to the leveling setting value or the leveling setting pattern, and ends operation after the tail end of the rolled material 1 passes directly below the work rolls 11 of the rolling stand _F1 .

The leveling control unit 23 corresponding to the rolling stand F _j (2≦j≦N) starts changing the leveling after the tail end of the rolled material 1 passes through the next upstream rolling stand F _j-1 .

In the learning step, the meandering control device 20 starts operating after the tail end of the rolled material 1 passes through the final meandering amount detection unit 3, the learning value update unit 24 performs a calculation to update the learning value, and stores the calculation result in the learning value storage unit 25, thereby terminating the operation.

(First operation example)
3 is a flow chart showing the process of repeating calculations performed by the meandering control device 20 in the setting step. Note that the dashed line frame shown in FIG.

When the set value updating unit 22 issues a read command to the prediction calculation unit 21 at the start of the setting step, the prediction calculation unit 21 acquires rolling information from the set-up device 30, acquires the initial meandering amount y _c0 from the initial meandering amount detection unit 2, reads the learning value from the learning value storage unit 25, and calculates each coefficient of the rolling model of each rolling stand (S100).

Each coefficient of the rolling model is a coefficient of the influence that the input or current state has on the future state. For example, a dynamics model expressed by the state space model shown in the following equations (1) to (5) is used for the rolling model.

Here, k is a parameter that increments from a value of 1, which indicates the start of operation of the rolling stand F _i, to a value of M _i , which indicates the end of operation.

The output vector z _i of equation (2) is expressed by equation (4) and is composed of the meandering amount and wedge amount immediately below the work roll 11. The input vector u _i is expressed by equation (5) and is composed of the output vector z _{i- 1 of the immediately upstream rolling stand F i-1} calculated by equation (2) and the roll gap leveling setting value δS _i of the rolling stand F _i .

However, in the case of the rolling stand _F1 located at the most upstream position, the initial meandering amount _yc0 is substituted for _zi-1 , and the initial wedge amount is assumed to be 0.

Here, the roll reduction leveling setting pattern δS _i is a roll reduction leveling setting value that changes with the parameter k shown in FIG.

The state equation (1) is not limited to a differential equation or difference equation that evolves with time, and a differential equation or difference equation that evolves with the rolling distance may be used. A state equation that evolves with the rolling distance has the advantage of being able to avoid dead time due to transportation and time changes in the inlet speed, and to linearize the state space model.

Here, the learning value may be given, for example, as a vector to be added to the right-hand side of equation (2) taking into account stationary modeling errors. Also, the rolling model is not limited to a dynamic model, and may be a linear model, etc.

The set value update unit 22 inputs the initial roll gap leveling values δS _ini,1 , δS _ini,2 , ..., δS _ini,N of each rolling stand to the prediction calculation unit 21 and issues a prediction command (S102). The initial set value is, for example, an average value of the roll gap leveling performance pattern of any section of the steady part of each rolling stand.

The prediction calculation unit 21 receives a prediction command, performs calculations using the rolling model based on the input conditions and the rolling model, sequentially starting from the rolling stand _F1 , and outputs the meandering amounts _yc1 , _yc2 , ..., _ycN and wedge amounts _δh1 , _δh2 , ..., _δhN after rolling in each rolling stand to the set value update unit 22 (S104).

The set value update unit 22 evaluates the acquired meandering amount after rolling of each rolling stand and the wedge amount after rolling of the final rolling stand (S106). The set value update unit 22 uses, for example, the evaluation function shown in the following formula (6) for the evaluation.

Then, the setting value update unit 22 judges whether the evaluation value satisfies a termination condition. The termination condition is, for example, a condition judged by whether the previous and current evaluation values are equal to or less than a preset value (S108).

If the termination condition is not satisfied, the set value updating unit 22 updates the roll leveling setting patterns δS ₁ , δS ₂ , . . . , δS _N of each rolling stand based on the evaluation value, and again issues a prediction command to the prediction calculation unit 21 (S110).

Updates based on evaluation values can be made, for example, by calculations using the quasi-Newton method, a well-known optimization technique.

Then, the meandering control device 20 repeats the calculations of prediction, evaluation, and update until a predetermined end condition is satisfied, and determines the roll leveling setting patterns δS ₁ , δS ₂ , . . . , δS _N of each rolling stand.

In addition, in the iterative calculation, a penalty term for the leveling may be added to the constrained optimization or equation (6) to take into account the mechanical limits of the rolling device.

The setting value update unit 22 outputs the determined roll leveling setting pattern to the roll leveling control unit 23 corresponding to each rolling stand.

The roll gap leveling control unit 23 corresponding to the rolling stand F _i stores the roll gap leveling setting pattern acquired in the setting step, and reads out the roll gap leveling setting value δS _i [1] at the start of the control step.

The leveling control unit 23 then operates the leveling control unit 13 sequentially with the leveling setting patterns δS _i [1], δS _i [2], ..., δS _i [M _i ] while calculating the elapsed time or rolling distance from the start of control.

In addition, taking into account the response delay or dynamic characteristics of the screw-down device, the sequential operation of the screw-down control unit 13 may be accelerated or compensation may be performed using a filter based on the transfer function of the dynamic characteristics.

Figure 5 is a flowchart showing the process in which the meandering control device 20 performs repeated calculations in the learning step. Note that the dashed line frame in Figure 5 shows the process performed by the prediction calculation unit 21.

The leveling control unit 23 corresponding to each rolling stand acquires time-series or rolling distance-series leveling performance patterns δS ₁ , δS ₂ , . . . , δS _N from the leveling control unit 13 at the start of the learning step and outputs them to the learning value update unit 24.

The learning value updating unit 24 acquires rolling information from the set-up device 30 and acquires a roll leveling performance pattern from the roll leveling control unit 23, and then acquires the initial roll meandering amount y _c0 from the initial roll meandering amount detection unit 2, the final roll meandering amount y _cM from the final roll meandering amount detection unit 3, and the learning value from the learning value storage unit 25, and issues a read command to the prediction calculation unit 21.

Furthermore, the learning value update unit 24 inputs the roll-down leveling performance pattern acquired from the roll-down leveling control unit 23 to the prediction calculation unit 21 and issues a prediction command.

The prediction calculation unit 21 first receives a read command, acquires a learning value from the learning value memory unit 25, and calculates each coefficient of the rolling model of each rolling stand from the acquired learning value and the rolling information input from the setup device 30 (S200).

However, for the second and subsequent read commands, the prediction calculation unit 21 uses the learning value provided by the learning value update unit 24 instead of obtaining the learning value from the learning value storage unit 25.

Next, the prediction calculation unit 21 receives a prediction command, performs calculations using the rolling model for _each rolling stand F1 in sequence based on the input conditions and the rolling model, and outputs the predicted meandering amount _ycN after rolling in the rolling stand _FN to the learning value update unit 24 (S202).

The learning value update unit 24 evaluates the prediction error using the acquired meandering amount _ycN after rolling in the rolling stand _FN and the final meandering amount _ycM measured at the corresponding rolled material position (S204). For example, the learning value update unit 24 uses an evaluation function shown in the following formula (7) for the evaluation.

Then, the learning value update unit 24 determines whether the evaluation value satisfies a termination condition. The termination condition is, for example, a condition determined by whether the previous and current evaluation values are equal to or less than a preset value (S206).

If the termination condition is not met, the learning value update unit 24 updates the learning value based on the evaluation value, inputs it to the prediction calculation unit 21, and issues a read command and a prediction command again (S208).

Updates based on evaluation values can be made, for example, by calculations using the quasi-Newton method, a well-known optimization technique.

The meandering control device 20 then determines the learning value by repeatedly calculating prediction, evaluation, and updates until a specified termination condition is met.

Finally, the learning value update unit 24 divides the learning value determined as described above proportionally to the initially acquired learning value, and updates the learning value stored in the learning value storage unit 25 as the final learning value. In this way, the meandering control device 20 determines the optimal learning value for the current rolling result.

(Second operation example)
In the second operation example of the meandering control device 20, instead of the roll down leveling setting pattern in the above-mentioned first operation example, a constant roll down leveling setting value is used during the control step.

The dynamics model is calculated by changing equation (5) to the following equation (8).

In the setting step, the setting value update unit 22 determines the roll leveling setting values δS ₁ , δS ₂ , ..., δS _N in the same manner as determining the roll leveling setting patterns δS ₁ , δS ₂ , ..., δS _N of each rolling stand described in the first operation example, and outputs them to the roll leveling control unit 23 of each rolling stand.

At the start of the control step, the roll gap leveling control unit 23 corresponding to the rolling stand F _i controls the roll gap leveling control unit 13 of the rolling stand F _i in accordance with the roll gap leveling set value δS _i acquired from the set value updating unit 22. Note that, taking into consideration the response delay of the roll gap device, the start of operation of the roll gap control unit 13 may be advanced.

(Third operation example)
In the third operation example of the meandering control device 20, the calculation cost is reduced by performing the repeated calculations in the setting steps described in the first operation example in order from the upstream rolling stand.

Fig. 6 is a diagram showing a schematic diagram of a tension state during rolling in a third operation example of the meandering control device 20. Fig. 6 shows sections of the rolled material 1 rolled without rear tension by each rolling stand of the continuous rolling mill 10, taking rolling stands _F1 to _F3 as an example.

As the rolled material 1 is rolled from upstream to downstream, it elongates at an elongation rate λ _i expressed as the ratio H _i /h _i of the entry thickness H _i to the delivery thickness h _i . In other words, the tension state of the rolled material 1 when it is rolled by each rolling stand differs depending on the position of the tail end.

First, the section in which each rolling stand rolls without rear tension (the hatched section in FIG. 6) is from the tail end to L in rolling stand _F2 and onwards, and from the tail end to Lt in rolling stand _F1 .

Next, since the length Lt on the entry side of rolling stand _F1 extends to the length _λ1 ×Lt on the exit side, the section from the position _λ1 ×Lt from the tail end to the position L from the tail end on the entry side of rolling stand _F2 (the horizontal line section in Figure 6) is rolled with rear tension.

Similarly, the section from the tail end to L (the hatched section in FIG. 6 ), which is rolled without rear tension by rolling stand _F2 , also extends to _λ2 ×L, so that the section from the position from the tail end to _λ2 ×L on the inlet side of rolling stand _F3 to the position from the tail end to L (the horizontal line section in FIG. 6 ) is rolled with rear tension.

As a result, the tension state by each rolling stand changes at each position of the rolled material 1. Although the description has been given here for the rolling stands F1 to _F3 , the same phenomenon is repeated up to the rolling stands F1 to _FN .

Figure 7 is a diagram showing the characteristics (tension state) at each position of the rolled material 1 after rolling in the third operation example of the meandering control device 20. The number of rolling stands is N as described above. Sections 1 to N are divided based on the tension state at each position of the rolled material 1 when it is rolled in each rolling stand.

Section i is rolled by rolling stands F ₁ to F _i without rear tension. Therefore, the amount of meandering in section i is due to the effect of the roll leveling of rolling stands F ₁ to F _i , and the effect of the roll leveling of rolling stands F _i+1 to F _N can be ignored.

Considering the above relationship, the roll gap leveling setting value _δS1 of the rolling stand _F1 may be determined so as to set _ycN to 0 at the boundary position between Section 1 and Section 2 for the amount of meandering _ycN after rolling by the rolling stand _FN predicted by the prediction calculation unit 21. In other words, the setting value updating unit 22 performs a process of updating to the determined roll gap leveling setting pattern _δS1 and issues a prediction command again.

Here, the prediction calculation unit 21 modifies equation (2) to equation (9) to make a prediction, assuming that in rolling stands where rolling is performed with rear tension, no rotation occurs due to changes in the wedge ratio.

Therefore, in section 1, since rolling is performed with rear tension from the rolling stand _F2 onwards, the predicted value of the meandering amount of each rolling stand is _yc1 = _yc2 = . . . = _ycN .

Note that the roll leveling of the rolling stand before the control step begins is given the initial roll leveling value described in the first operation example.

Next, the roll clearance leveling set value _δS2 of the rolling stand _F2 may be determined so as to set the amount of _{meandering ycN} after rolling by the rolling stand _FN to 0 at the boundary position between section 2 and section 3. The set value updating unit 22 determines the roll clearance leveling set values _δS1 , ..., _δSN in the same manner, starting from the upstream rolling stand.

(Fourth operation example)
In the fourth operation example of the meandering control device 20, the repeated calculations in the setting steps described in the third operation example are performed in order starting from the upstream rolling stand, and the roll reduction leveling setting value is determined taking into account the wedge amount after rolling by the final rolling stand, thereby improving the wedge quality.

The set value update unit 22 evaluates the amount of meandering and the amount of wedge after rolling by the final rolling stand predicted by the prediction calculation unit 21 for the roll leveling δS _i of the rolling stand F _i , focusing on the position of the boundary between the section i and the section i+1 of the rolled material 1, using the evaluation function of Equation (10).

The meandering control device 20 then changes the roll leveling set value δS _i of the rolling stand F _i until a predetermined end condition is satisfied, and repeats re-prediction to determine the value, where i is an integer from 1 to N.

For example, when i=3, the set value update unit 22 inputs to the prediction calculation unit 21 already determined set values for the roll leveling set values δS ₁ and δS ₂ , and initially set values for the roll leveling set values δS ₄ to δS _N.

(Fifth operation example)
In the fifth operation example of the meandering control device 20, the calculation cost is reduced by performing the repeated calculation in the learning step described in the first operation example in order from the upstream rolling stand. For example, the learning value update unit 24 uses the error between the meandering amount predicted by the prediction calculation unit 21 and the detected meandering amount in order from section 1 to obtain the learning value in order from the rolling stand _F1 .

The learning value of the rolling stand _F1 may be determined so that the meandering amount at the boundary position between the section 1 and the section 2 coincides with _ycM with respect to the meandering amount _ycN after rolling by the rolling stand _FN predicted by the prediction calculation unit 21. Then, the learning value update unit 24 updates the determined learning value of the rolling stand _F1 , and again issues a read command and a prediction command.

Next, the learning value of the rolling stand _F2 may be determined so that the meandering amount at the boundary position between Section 2 and Section 3 coincides with _ycM for the meandering amount _ycN after rolling by the rolling stand _FN . The learning value update unit 24 then determines the learning values in the order from the upstream rolling stand in the same manner. Finally, the learning value update unit 24 allocates the learning values of each rolling stand determined as described above to the initially acquired learning value, and updates the learning values stored in the learning value storage unit 25 as the final learning values.

In this way, the meandering control device 20 controls the roll leveling of each of the multiple rolling stands based on the roll leveling setting values updated by the setting value update unit 22, so that even if the continuous rolling mill 10 continuously rolls the rolled material 1, it can control the rolling to achieve stable sheet passing while maintaining wedge quality.

Next, a modified example of the rolling system 100 will be described. Figure 8 is a diagram illustrating an example of the configuration of the meandering control device 20a and its surrounding configuration in a modified example of the rolling system 100 (rolling system 100a).

The rolling system 100a differs from the rolling system 100 (see FIGS. 1 and 2) in that it has, for example, one or more inter-stand meandering amount detection units 4 between predetermined rolling stands. For example, the rolling system 100a has one inter-stand meandering amount detection unit 4 installed between rolling stands F _i-1 and F _i . The inter-stand meandering amount detection unit 4 may be installed between any of the rolling stands F ₁ to F _N. The maximum number of inter-stand meandering amount detection units 4 installed is N-1.

The meandering control device 20a then uses the inter-stand meandering amount detected by the inter-stand meandering amount detection unit 4 to determine a learning value to improve the accuracy of the rolling model.

For example, the learning value update unit 24a also has a function of evaluating the amount of meandering detected by the inter-stand meandering amount detection unit 4 and the amount of meandering predicted by the prediction calculation unit 21 using an evaluation function, and updating the learning value until a predetermined termination condition based on the evaluation result is satisfied.

In the above-mentioned first operation example of the meandering control device 20, the prediction calculation unit 21 predicts the meandering amount _yc0 to the meandering amount _ycN after rolling by the rolling stand _FN , and the learning value update unit 24a calculates the learning value so that the meandering amount _ycN coincides with the final meandering amount _ycM .

In this case, errors in the rolling model of the upstream rolling stand may propagate downstream and affect the predictions of the downstream rolling stands.

When the inter-stand meandering amount detection unit 4 is installed between rolling stands F _i-1 and F _i , the meandering control device 20a divides the rolling stands F ₁ to F _i-1 into the upstream side and the rolling stands F _i to F _N into the downstream side, and repeatedly calculates and updates the learning values.

The amount of meandering between F _i-1 and _{F i} detected by the inter-stand meandering amount detection unit 4 is represented as y _si . The amount of meandering between F _i-1 and F _i y _si is compared with the amount of meandering y _ci-1 after rolling by the rolling stand F i _{-1 using the position of the rolled material 1 rolled with rear tension in the rolling stand F i} , for example, the section i-1 in FIG. 7.

9 is a flow chart showing the process in which the meandering control device 20a performs repetitive calculations in the learning step. In the repetitive calculations, first, for the upstream rolling stands F ₁ to F _i-1 , the learned values are updated in the same manner as in the first operation example using the meandering amount y _{c i-1 after} rolling by the rolling stand F _{i-1 and the F i-1} - _{F i} meandering amount y _si measured at the corresponding position of the rolled material 1 (upstream processing: S300 to S308).

Here, the evaluation function is changed from formula (7) to formula (11) below.

Here, the F _i-1 -F _i meandering amount y _si is resampled in advance by linear interpolation so as to correspond to the parameter k of the rolling stand F i _-1 , and is shifted based on the distance between the position just below the work roll 11 of the rolling stand F _i-1 and the meandering amount detection position, and the transport speed between the rolling stands F _i-1 -F _i .

The interval to be evaluated is from k= ₁ corresponding to the boundary between interval i-2 and interval i-1 to k=M _i-1 ' corresponding to the boundary between interval i-1 and interval i in the rolling model for rolling stand F i-1, and M _i-1 ' is calculated by the following formula (12). Here, Int() is a function that rounds down to the nearest whole number. Note that interval 0 means the steady portion.

Then, the learning value updating unit 24a uses the learning values obtained as described above for the upstream rolling stands F ₁ to F _i-1 to determine learning values for the downstream rolling stands. The learning value updating unit 24a updates the learning values for the downstream rolling stands F _i to F _N in the same manner as in the first operation example, using the meandering amount y _cN after rolling by the rolling stand F _N and the final meandering amount y _cM . Finally, the learning value updating unit 24a apportions the learning values for each rolling stand determined as described above to the initially acquired learning values, and updates the learning values stored in the learning value storage unit 25 as final learning values (downstream processing: S400 to S408).

In this way, the meandering control device 20a updates the learning value stored in the learning value memory unit 25 using the meandering amount of the rolled material 1 after passing through the most downstream rolling stand predicted by the prediction calculation unit 21 and the final meandering amount, so that even if the continuous rolling mill 10 continuously rolls the rolled material 1 while changes over time may occur, it can be controlled to achieve stable sheet threading while maintaining wedge quality.

Next, an example of the hardware configuration of the meandering control device 20 (or the meandering control device 20a) will be described. FIG. 10 is a conceptual diagram showing an example of the hardware configuration of the processing circuit of the meandering control device 20 (or the meandering control device 20a). Each part in the meandering control device 20 represents a part of the function, and each function is realized by the processing circuit.

In one embodiment, the processing circuitry includes at least one processor 91 and at least one memory 92. In another embodiment, the processing circuitry includes at least one dedicated hardware 93.

When the processing circuit includes a processor 91 and a memory 92, each function is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. In addition, at least one of the software and firmware is stored in the memory 92.

The processor 91 realizes each function by reading and executing the programs stored in the memory 92.

When the processing circuitry includes dedicated hardware 93, the processing circuitry may be, for example, a single circuit, a composite circuit, a programmed processor, or a combination of these. Each function is then realized by the processing circuitry.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1: Rolled material, 2: Initial meandering amount detection unit, 3: Final meandering amount detection unit, 4: Inter-stand meandering amount detection unit, 10: Continuous rolling mill, 11: Work roll, 12: Backup roll, 13: Rolling control unit, 20, 20a: Meandering control unit, 21: Prediction calculation unit, 22: Setting value update unit, 23: Rolling leveling control unit, 24, 24a: Learning value update unit, 25: Learning value storage unit, 30: Setup device, 91: Processor, 92: Memory, 93: Hardware, 100, 100a: Rolling system, F1 to FN: Rolling stands

Claims (6)

A meandering control device for controlling the meandering of a material in a continuous rolling mill having a plurality of rolling stands through which a material passes and a rolling force is sequentially applied,
a prediction calculation unit that predicts the meandering amount and wedge amount of each of the tail ends of the material after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands using rolling information that specifies an initial meandering amount of the material before rolling, a final meandering amount of the material rolled by all of the rolling stands, a roll-down leveling setting value for each of the multiple rolling stands, and settings of a rolling process;
a set value updating unit that updates a roll leveling set value for each of the plurality of rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit;
and a plurality of roll leveling control units for controlling roll leveling of the plurality of rolling stands , based on each of the roll leveling set values updated by the set value update unit,
The setting value update unit
repeating evaluation using an evaluation function based on the meandering amount and wedge amount predicted by the prediction calculation unit until a predetermined termination condition is satisfied so that the roll gap leveling setting value for each of the plurality of rolling stands becomes a time-series or rolling distance series roll gap leveling setting pattern, and updating the roll gap leveling setting value for each of the plurality of rolling stands;
The roll down leveling control unit is
A meandering control device characterized in that the set value update unit controls the roll leveling of the rolling stand based on the roll leveling setting pattern, time, and inlet speed of the material updated. A meandering control device for controlling the meandering of a material in a continuous rolling mill having a plurality of rolling stands through which a material passes and a rolling force is sequentially applied,
a prediction calculation unit that predicts the meandering amount and wedge amount of each of the tail ends of the material after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands using rolling information that specifies an initial meandering amount of the material before rolling, a final meandering amount of the material rolled by all of the rolling stands, a roll-down leveling setting value for each of the multiple rolling stands, and settings of a rolling process;
a set value updating unit that updates a roll leveling set value for each of the plurality of rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit;
a plurality of roll leveling control units for controlling roll leveling of the plurality of rolling stands based on the roll leveling set values updated by the set value update unit;
having
The setting value update unit
a roll gap leveling set value is set to a constant value, and evaluation using an evaluation function based on the roll gap and wedge amount predicted by the prediction calculation unit is repeated until a predetermined termination condition is satisfied, thereby updating the roll gap leveling set value for each of the plurality of rolling stands. A meandering control device for controlling the meandering of a material in a continuous rolling mill having a plurality of rolling stands through which a material passes and a rolling force is sequentially applied,
a prediction calculation unit that predicts the meandering amount and wedge amount of each of the tail ends of the material after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands using rolling information that specifies an initial meandering amount of the material before rolling, a final meandering amount of the material rolled by all of the rolling stands, a roll-down leveling setting value for each of the multiple rolling stands, and settings of a rolling process;
a set value updating unit that updates a roll leveling set value for each of the plurality of rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit;
a plurality of roll leveling control units for controlling roll leveling of the plurality of rolling stands based on the roll leveling set values updated by the set value update unit;
having
The setting value update unit
a meandering control device which performs an evaluation using an evaluation function based on a meandering amount and a wedge amount of a predetermined point of the tail end of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit, for each of the plurality of rolling stands, in order from the upstream side, until a predetermined termination condition is satisfied, and updates a roll gap leveling setting value for each of the plurality of rolling stands based on the evaluation result. A meandering control device for controlling the meandering of a material in a continuous rolling mill having a plurality of rolling stands through which a material passes and a rolling force is sequentially applied,
a prediction calculation unit that predicts the meandering amount and wedge amount of each of the tail ends of the material after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands using rolling information that specifies an initial meandering amount of the material before rolling, a final meandering amount of the material rolled by all of the rolling stands, a roll-down leveling setting value for each of the multiple rolling stands, and settings of a rolling process;
a set value updating unit that updates a roll leveling set value for each of the plurality of rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit;
a plurality of roll leveling control units for controlling roll leveling of the plurality of rolling stands based on the roll leveling set values updated by the set value update unit;
A learning value storage unit that stores a learning value used for adjusting the rolling model;
a learning value update unit that updates the learning value stored in the learning value storage unit;
having
The plurality of roll leveling control units include
A time-series or rolling distance-series roll leveling performance pattern is acquired from each of the plurality of rolling stands;
The prediction calculation unit is
predicting a meandering amount and a wedge amount of each of the tail ends of the material after passing through each of the plurality of rolling stands based on a rolling model of each of the plurality of rolling stands using the initial meandering amount, the final meandering amount, each of the roll leveling performance patterns acquired by the plurality of roll leveling control units, the rolling information, and a learning value stored in the learning value storage unit;
The learning value update unit is
a meandering amount of the material after passing through the most downstream rolling stand predicted by the prediction calculation unit and the final meandering amount, and an evaluation is repeated using an evaluation function that uses the final meandering amount, and updates a learning value for each of the plurality of rolling stands until a predetermined termination condition is satisfied . A meandering control device for controlling the meandering of a material in a continuous rolling mill having a plurality of rolling stands through which a material passes and a rolling force is sequentially applied,
a prediction calculation unit that predicts the meandering amount and wedge amount of each of the tail ends of the material after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands using rolling information that specifies an initial meandering amount of the material before rolling, a final meandering amount of the material rolled by all of the rolling stands, a roll-down leveling setting value for each of the multiple rolling stands, and settings of a rolling process;
a set value updating unit that updates a roll leveling set value for each of the plurality of rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit;
a plurality of roll leveling control units for controlling roll leveling of the plurality of rolling stands based on the roll leveling set values updated by the set value update unit;
A learning value storage unit that stores a learning value used for adjusting the rolling model;
a learning value update unit that updates the learning value stored in the learning value storage unit;
having
The plurality of roll leveling control units include
A time-series or rolling distance-series roll leveling performance pattern is acquired from each of the plurality of rolling stands;
The prediction calculation unit is
predicting a meandering amount and a wedge amount of each of the tail ends of the material after passing through each of the plurality of rolling stands based on a rolling model of each of the plurality of rolling stands using the initial meandering amount, the final meandering amount, each of the roll leveling performance patterns acquired by the plurality of roll leveling control units, the rolling information, and a learning value stored in the learning value storage unit;
The learning value update unit is
a learning value is updated so that an error between a meandering amount of a predetermined point of the tail end of the material after passing through the most downstream rolling stand, which is predicted by the prediction calculation unit, and the final meandering amount becomes zero. A meandering control device for controlling meandering of a material in a continuous rolling mill having a plurality of rolling stands through which a material passes and a rolling force is sequentially applied,
a prediction calculation unit that predicts the meandering amount and wedge amount of each of the tail ends of the material after passing through each of the multiple rolling stands based on a rolling model of each of the multiple rolling stands using rolling information that specifies an initial meandering amount of the material before rolling, a final meandering amount of the material rolled by all of the rolling stands, a roll-down leveling setting value for each of the multiple rolling stands, and settings of a rolling process;
a set value updating unit that updates a roll leveling set value for each of the plurality of rolling stands based on the meandering amount and wedge amount of each of the material tail ends predicted by the prediction calculation unit;
a plurality of roll leveling control units for controlling roll leveling of the plurality of rolling stands based on the roll leveling set values updated by the set value update unit;
A learning value storage unit that stores a learning value used for adjusting the rolling model;
a learning value update unit that updates the learning value stored in the learning value storage unit;
having
The plurality of roll leveling control units include
A time-series or rolling distance-series roll leveling performance pattern is acquired from each of the plurality of rolling stands;
The prediction calculation unit is
predicting a meandering amount and a wedge amount of each of the tail ends of the material after passing through each of the plurality of rolling stands based on a rolling model of each of the plurality of rolling stands using the initial meandering amount, the final meandering amount, each of the roll leveling performance patterns acquired by the plurality of roll leveling control units, the rolling information, and a learning value stored in the learning value storage unit;
The learning value update unit is
a meandering amount detected by an inter-stand meandering amount detection unit which detects the amount of meandering of the material between the rolling stand and another rolling stand, and a meandering amount predicted by the prediction calculation unit are evaluated by an evaluation function, and a learning value is updated until a predetermined termination condition based on the evaluation result is satisfied.

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