JP2009208115A - Method and device for calculating parameter of rolling control, and rolling simulation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate optimally adjusted parameters of rolling control by identifying friction coefficients of the whole of a rolling machine and by performing, based on the obtained friction coefficients, a simulation to reproduce a rolling state. <P>SOLUTION: A dynamic model of rolling is previously prepared. Concerning a temporal change of rolling loads or roll gaps at a plurality of rolling stands when accelerating or decelerating a rolling material, the difference between a calculated value of the temporal change, which is obtained from the dynamic model of rolling, and an actual value of the temporal change is made minimum by optimizing a friction coefficient parameter or a deformation resistance parameter at each rolling stand. Using the dynamic model of rolling into which these parameters are incorporated, parameters of rolling control are calculated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and a device for calculating an optimized rolling control parameter for a rolling mill having a plurality of rolling stands, and a rolling simulation device capable of calculating an optimized rolling control parameter. .

As a method for calculating an optimally adjusted parameter regarding a control parameter (rolling control parameter) for controlling the rolling mill, for example, there is one disclosed in Patent Document 1.
The simulation apparatus disclosed in Patent Document 1 includes a model unit that models various plants such as a rolling mill, and a block element unit that models a control device that controls the various plants. The parameters of various plants are changed. Regarding the change of the parameter in the above-mentioned model means, a person familiar with the plant changes the parameter so that the error signal is less than the allowable error, or the inference means is provided to change the parameter, or the parameter is changed by the identification mechanism. I am going to change it.

On the other hand, Patent Document 2 discloses a roll gap correction device for a rolling mill composed of a single rolling stand. In this equipment, when correcting the change in the thickness of the rolling stand exit side due to the change in the friction coefficient, a model formula of the friction coefficient is estimated using a neural network, and the value obtained from this estimation formula is used to estimate the rolling stand. The roll gap setting value (control parameter) is corrected.
JP 63-239508 A JP-A-7-246411

However, in order to apply the techniques of Patent Documents 1 and 2 to control when accelerating or decelerating a rolled material with a rolling mill having a plurality of rolling stands, there are problems as described below.
For example, when the technique of Patent Document 1 is applied at the time of acceleration / deceleration of the rolling material, parameter change based on "expert knowledge by qualitative expression" possessed by a person familiar with the plant or parameter change by inference means, As described in Patent Document 1, it is ambiguous information and it is clear that accurate plant control cannot be performed. Also, with regard to a method of changing parameters by an identification mechanism, the present technology is limited to a linear system and cannot identify a nonlinear system.

  Moreover, in order to calculate a rolling load using the rolling load formula with the technique of patent document 2, the data of an entrance side plate thickness, an exit side plate thickness, front tension, and back tension are required, but since there is no sensor. Often there is no data available. In this case, the method of Patent Document 2 cannot be applied. Even when data is obtained, there are effects due to dead time caused by the sensor mounting position and delay time due to signal processing, and all of the inlet side thickness, outlet side thickness, front tension, and rear tension Cannot be maintained at the same time, that is, at the same time. That is, since the rolling load formula of Patent Document 2 is static, an error in data that cannot maintain simultaneity is not considered, and a transient state such as during rolling acceleration / deceleration cannot be accurately expressed.

Moreover, the technique of patent document 2 is for a single rolling stand, and it is technically difficult to apply to a rolling mill having a plurality of rolling stands because interference with other rolling stands is not considered.
In other words, in a rolling mill equipped with a plurality of rolling stands, each rolling stand interferes with each other via a rolling material and a control system.For example, the exit side plate thickness deviation of the upstream rolling stand is that of the downstream rolling stand. Affects the thickness deviation on the delivery side. For this reason, it is necessary to consider the dynamic characteristics of the upstream rolling stand. Further, the deviation of the downstream thickness and tension may be on the upstream side, and this upstream influence may be the downstream thickness deviation of the downstream rolling stand again. This is because the entire multi-stand rolling mill is a system that is integrally connected by a rolled material, and is a system that is integrally connected by a control system such as speed-successive or plate thickness control. For this reason, in the case of a rolling mill provided with a plurality of rolling stands, an entire simulation is required. In particular, for the high-precision simulation of the finishing plate thickness, it is important to improve the accuracy of the simulation of the upstream rolling stand.

In the technique of Patent Document 2, attention is paid to a friction coefficient that greatly affects rolling, and the friction coefficient is identified using a friction coefficient model so that the error is reduced. However, errors in the deformation resistance model of the rolled material, non-linearity such as a dead zone of tension in the control system, and transient response of the control system are not considered. Therefore, there is a high possibility that the error becomes large as a simulation of the whole rolling.
Because of the problems described above, even when the techniques of Patent Documents 1 and 2 are adopted for the control when accelerating and / or decelerating the rolling material with a rolling mill equipped with a plurality of rolling stands, the optimally adjusted rolling control is adopted. It was difficult to calculate the parameters.

In view of the above problems, the present invention uses a rolling dynamic model that dynamically expresses a rolled material, a plurality of rolling stands that roll the rolled material, and a control system that controls the thickness of the rolling stand. The friction coefficient and / or deformation resistance of the entire rolling mill is identified, and the simulation is performed to reproduce the rolling state based on the obtained friction coefficient and / or deformation resistance, and the optimally adjusted rolling control parameters are calculated. An object of the present invention is to provide a rolling control parameter calculation method and calculation device.
In addition, a rolling simulation apparatus that identifies the friction coefficient and / or deformation resistance of the entire rolling mill using the rolling dynamic model and reproduces the rolling state with high accuracy by the obtained friction coefficient and / or deformation resistance. The purpose is to provide.

In order to achieve the above object, the present invention takes the following technical means.
That is, the rolling control parameter calculation method according to the present invention is a rolling dynamic model that dynamically expresses a rolled material, a plurality of rolling stands that roll the rolled material, and a control system that controls the thickness of the rolling stand. And the calculated value and the actual value of the rolling dynamic model with respect to the time change of the rolling load and / or the time change of the roll gap at the time of acceleration and / or deceleration of the rolled material. The parameters related to the friction coefficient and / or the deformation resistance at each rolling stand are optimized so that the evaluation function including the difference is minimized, and the optimized parameters related to the friction coefficient and / or the deformation resistance are incorporated. Further, using the rolling dynamic model, the rolling control parameters including the setting parameters for the plate thickness control and / or the setting parameters for the rolling stand are used. And wherein the optimizing to calculate a meter.

Note that the rolling control parameter referred to here is a setting parameter related to sheet thickness control and / or a setting parameter related to a rolling mill, such as acceleration / deceleration compensation amount, control gain, dead band width, target tension value, tuning rate, droop rate, etc. This is a parameter that affects the rolling state and can be set, such as speed-dependent characteristics. The parameters that can be set are not only numerical values but also tables and functions. The minimum evaluation function includes changing the sign to maximize it. The same applies hereinafter.
According to this rolling control parameter calculation method, a rolling dynamic model capable of expressing rolling transient characteristics is used to identify the friction coefficient and / or deformation resistance of the entire rolling mill, and the obtained friction coefficient and / or A simulation that accurately reproduces the rolling state based on the deformation resistance can be performed to calculate the optimally adjusted rolling control parameter.

  The simulation of the entire rolling system using such a rolling dynamic model can calculate those values even when the plate thickness and tension cannot be measured in practice, and parameters related to the friction coefficient and / or deformation resistance and rolling control. Various parameters such as parameters can be adjusted. Note that the case where measurement is impossible here means that the sensor itself does not exist, or even if it exists, it cannot be used because it cannot be extracted outside simply by using the measured value inside, or it cannot be used due to insufficient accuracy. In addition, it means a case where accurate data cannot be used, such as when the measurement time has a large error and cannot be used. Various parameters can be adjusted even when there is a measurement delay in the plate thickness or tension, for example, a delay due to a plate transfer distance or a delay due to a filter, that is, there is no simultaneity of all items of the performance data.

Further, by using this technical means, various parameters can be identified without performing any special operation on the actual rolling mill or a control unit for controlling the rolling mill, which is safe in operation.
Preferably, calculation of optimization of the parameter relating to the friction coefficient and / or the parameter relating to deformation resistance may be performed in order from the upstream rolling stand to the downstream rolling stand.
In addition, the calculation of the parameter relating to the friction coefficient and / or the parameter relating to the deformation resistance may be performed once or a plurality of times for each rolling stand.
The parameter relating to the friction coefficient preferably includes an upper limit rolling speed that is an upper limit rolling speed at which the friction coefficient does not change, and a variable that defines a friction coefficient at a rolling speed of zero.

  The rolling control parameter calculation apparatus according to the present invention includes a rolling mill model unit that models a rolled material and a plurality of rolling stands that roll the rolled material, and a plate thickness control that performs plate thickness control of the rolling stand. The rolling dynamic model part provided with a model part, and the rolling dynamic model part regarding the time change of the rolling load and / or the time change of the roll gap at the time of acceleration and / or deceleration of the rolled material A rolling state parameter optimizing unit that optimizes a parameter relating to a friction coefficient and / or a parameter relating to deformation resistance in each rolling stand so that an evaluation function including a difference between a calculated value and an actual value is minimized. The rolling dynamic mode in which the parameter relating to the friction coefficient and / or the parameter relating to deformation resistance optimized by the rolling state parameter optimization unit is incorporated. It is using pole tip, and having a a rolling control parameter optimization unit for calculating and optimizing the rolling control parameters including configuration parameters configuration parameters and / or rolling stands of the thickness control.

In addition, the rolling state parameter said here is a parameter regarding a rolling mill (rolled material and rolling stand), and influences a rolling state, such as a friction coefficient, deformation resistance, and these speed-dependent characteristics, and parameters that cannot be set. Say. The rolling state parameter may be not only a numerical value but also a table or a function.
Using this rolling control parameter calculation device, the friction coefficient and / or deformation resistance of the entire rolling mill is identified, and a simulation is performed to accurately reproduce the rolling state based on the obtained friction coefficient and / or deformation resistance. Thus, the optimally adjusted rolling control parameter can be calculated.

  The rolling simulation apparatus according to the present invention includes a rolling mill model unit that models a rolled material and a plurality of rolling stands that roll the rolled material, and a plate thickness control model unit that performs plate thickness control of the rolling stand. The rolling dynamic model section provided, and the rolling dynamic model section calculates the time change of the rolling load and / or the time change of the roll gap at the time of acceleration and / or deceleration of the rolled material. A rolling state parameter optimizing unit that optimizes a parameter relating to a friction coefficient and / or a parameter relating to deformation resistance in each rolling stand so that an evaluation function including a difference between a value and an actual value is minimized, and the rolling state parameter The rolling dynamic model incorporating a parameter relating to a friction coefficient and / or a parameter relating to deformation resistance optimized by an optimization unit A rolling control parameter optimization unit that optimizes and calculates a rolling control parameter including a setting parameter of the plate thickness control and / or a setting parameter of a rolling stand, and the rolling dynamic model unit is The rolling condition can be reproduced by using the friction coefficient parameter and / or deformation resistance parameter optimized by the rolling condition parameter optimization unit and the rolling control parameter optimized by the rolling control parameter optimization unit. It is comprised as follows.

  By using this rolling simulation apparatus, the friction coefficient and / or deformation resistance of the entire rolling mill can be identified, and the rolling state can be accurately reproduced based on the obtained friction coefficient and / or deformation resistance.

By using the rolling control parameter calculation method and calculation apparatus according to the present invention, it is possible to calculate a rolling control parameter capable of improving the plate thickness accuracy without deteriorating the shape of the rolled material during acceleration / deceleration of the rolled material.
By using the rolling simulation apparatus according to the present invention, the friction coefficient and / or deformation resistance of the entire rolling mill can be identified, and the rolling state can be reproduced with high accuracy by the obtained friction coefficient and / or deformation resistance.

Embodiments of a rolling control parameter calculation method, calculation device, and rolling simulation device according to the present invention will be described below with reference to the drawings.
The rolling control parameter calculation device 1 (rolling simulation device) according to the present invention is a simulation model realized on a computer. Examples of the tool or language used include, but are not limited to, The Mathworks Matlab / Simulink (Matlab, Simulink is a registered trademark of The Mathworks), C language, and Fortran language.

FIG. 1 shows a block diagram of a rolling control parameter calculation device 1.
As shown in this figure, the calculation device 1 includes a rolling stand 2 and a rolling mill model unit 4 that models a rolling material 3 that is cold-rolled by the rolling stand 2, and the roll speed and roll gap of the rolling stand 2. And a plate thickness control model unit 5 to be operated. The rolling mill model unit 4 and the plate thickness control model unit 5 constitute a rolling dynamic model unit 6.
Further, the calculation device 1 includes a rolling control parameter optimization unit 7 that optimizes rolling control parameters, and a rolling state parameter optimization unit 8 that calculates rolling state parameters including an optimized friction coefficient and / or deformation resistance. It is equipped with.

The rolling control parameters referred to here are setting parameters related to sheet thickness control and setting parameters related to the rolling mill, and include acceleration / deceleration compensation amount, control gain, dead band width, target tension value, tuning rate, droop rate, and these speeds. It refers to parameters that influence the rolling state and can be set, such as dependency characteristics.
The rolling state parameter is a parameter relating to a rolling mill (rolled material and rolling stand), and refers to a parameter that affects the rolling state and cannot be set, such as a friction coefficient, deformation resistance, and speed-dependent characteristics thereof.

FIG. 2 shows a schematic diagram of the “rolling stand 2 and rolled material 3” modeled by the rolling mill model unit 4.
A plurality of rolling stands 2 (# 1 to # 5) are provided, and a tandem rolling mill 9 is provided. After the base plate is passed through the # 1 rolling stand 2, each time it passes through the # 2 to # 4 rolling stand 2, it is squeezed down, and when it exits the # 5 rolling stand 2, The roll speed and roll gap of the rolling stand 2 are controlled.
The rolling mill model unit 4 has a model of the rolling stand 2. As the model of the rolling stand 2, those disclosed in p111 to 124 of "Theory and practice of plate rolling, edited by the Japan Iron and Steel Institute, 1984" can be adopted, as shown in equations (1) to (9). It has become a thing.

Regarding the transfer of the rolling material 3 between the rolling stands 2 and 2, the exit side plate thickness of the rolling stand 2 located on the upstream side is moved to the rolling stand 2 at the exit side plate speed.
Therefore, it becomes possible to divide the rolled material 3 between the mill stands 2, 2 into a plurality of portions (sample plate piece), the sampling period of optimization calculation When Delta] t _s, the sample plate piece V _out for each sampling _{period, i} -By moving by Δt _s, the plate thickness of the sample plate piece that has reached the position of the # i + 1 rolling stand 2 can be made the entry side plate thickness H _{i + 1} of the # i + 1 stand.
First, when optimizing the friction coefficient mu _i as the initial value of the friction coefficient mu _i during rolling model equation, set the estimated or learned value from the actual result value obtained from the rolling mill 9. For example, as shown in FIG. 5A of Japanese Patent Laid-Open No. 10-249421 “Control device for rolling mill”, when the rolling speed is low, the friction coefficient is large, and when the rolling speed is higher than a predetermined speed, The friction coefficient is preferably set to be small and constant. If the friction coefficient μ _i is not optimized, the friction coefficient μ _i remains the initial value, and optimization described later is not performed.

When optimizing the deformation resistance k _i as the initial value of the deformation resistance k _i, known of the formula or the like depending on the static deformation resistance and the strain rate, i.e. Theory and Practice "plate rolling, the Japan Iron and Steel It can be obtained from any one of formulas (7.51) to (7.53) disclosed in p. When the deformation resistance k _i is not optimized, the deformation resistance k _i remains at the initial value, and optimization described later is not performed.
Also, assuming that the tension between the stands at the previous sampling time is obtained, and the entry and exit tensions of the rolling stand 2 are obtained from the actual values and actual parameters, the advanced rate is obtained from the equation (3). From the equations (1) and (2), the entry / exit plate speeds of the respective rolling stands 2 can be obtained. Here, the roll speed of Formula (1) and Formula (2) can be calculated | required using Formula (4).

Furthermore, the current can be calculated using the equation (7), and the tension between the stands at the current sampling time can be obtained using the equations (8) and (9). The stand exit side plate thickness and the rolling load can be obtained by simultaneous equations (5) and (6).
In addition, as a specific formula of the advanced rate (formula (3)), the method of Brand & Ford disclosed in p33 to 35 of “Theory and practice of plate rolling, edited by Japan Iron and Steel Institute, 1984” can be mentioned.
The reverse rate is obtained from a constant mass flow law of (1 + b _i ) · H _i = (1 + f _i ) · h _i .

The specific formula of the rolling load (formula (6)) is the formula (2.97) and formula (2.185) disclosed in p19 to 36 of "Theory and practice of plate rolling, edited by Japan Iron and Steel Institute, 1984". ), And Hill's equation (2.194).
The specific formula of the current (formula (7)) is the formula (2.104), formula (2.186), formula (p.20 to p35 of “Theory and practice of plate rolling, edited by the Japan Steel Association, 1984”) The torque of the Hill equation of 2.192) may be converted into a current and used. For example, the current is obtained by dividing by the torque constant.

From the above, simulation of # 1 rolling stand 2 to # 5 rolling stand 2 is possible. By inputting the rolling speed pattern, the sheet thickness history of the base plate, and the deformation resistance history with respect to these equations, it is possible to reproduce variations in the finished plate thickness, rolling load, and roll gap.
In an actual rolling stand 2, a load meter that measures the rolling load of each stand is usually installed in each rolling stand 2. However, there are cases where a thickness gauge and tension meter are not installed. In such a case, the thickness and tension value of the rolling stand 2 cannot be known. It is possible to calculate the stand outlet side plate thickness that cannot be calculated.

The rolling stand 2 model includes dynamic characteristics on the inlet side of the most upstream rolling stand 2 and dynamic characteristics on the outlet side of the most downstream rolling stand 2, for example, a rolling stand by a winding device (not shown). (2) A relational expression representing a change in tension on the outlet side may be included. When local control such as motor control of the rolling stand 2 or rigidity control of the rolling stand 2 is performed, these controls are included in the rolling stand 2 and the rolling material 3 part. The dynamic characteristics of the tension between the rolling stands 2 and 2 are included.
The plate thickness control model unit 5 includes a target plate thickness setting unit 10, a target tension setting unit 11, a plate thickness tension control unit 12, an acceleration / deceleration compensation unit 13, and a rolling speed pattern determination unit 14.

Note that the target tension setting unit 11 is not required when tension control is not performed. Further, the plate thickness tension control unit 12 controls at least the outlet side plate thickness (finished plate thickness) of the # 5 rolling stand 2 to be constant, but all or one of the outgoing side plate thicknesses in the other rolling stands 2 are also controlled. Those that control the part, or those that control all or part of the tension between the stands.
As shown in FIGS. 1 and 3, the target value of the exit side plate thickness of the # 1 to # 5 rolling stands 2 preset in the target plate thickness setting unit 10 is input to the plate thickness tension control unit 12. Similarly, a target value of the tension between the rolling stands 2 preset in the target tension setting unit 11 is input to the plate thickness tension control unit 12. In FIG. 3, the tension between # 12 stands means the tension of the rolling material 3 between the # 1 rolling stand 2 and the # 2 rolling stand 2. FIG. 3 shows an example of the plate thickness tension control unit 12 in the case of controlling the exit side plate thickness of all stands and the tension between all stands.

The outputs of the plate thickness tension control unit 12 are the roll gap in the # 1 to # 5 rolling stands 2 and the roll speed in the # 1 to # 4 rolling stands 2.
As the control performed in the plate thickness tension control unit 12, a publicly known one can be adopted, and PI control or optimum control may be used. For example, the method of “development of cold rolling tandem mill high-accuracy sheet thickness control technology” (The Institute of Electrical Engineers of Japan, Metal Industry Research Society, MID-01 to 9, March 16, 2001) may be used.
Further, in each rolling stand 2, the exit side plate thickness and the tension between the rolling stands 2 and 2 are measured or calculated, and the result is fed back to the plate thickness tension control unit 12.

In the case of the present embodiment, as shown in FIG. 1, a rolling speed pattern determining unit 14 that determines a rolling speed pattern in the reference rolling stand 2 (# 5 rolling stand) is provided.
The rolling speed pattern determining unit 14 determines a rolling speed pattern (change in rolling speed with time) in the # 5 rolling stand 2 when rolling one coil (one rolled material 3). For example, as shown in FIG. 4, a trapezoid pattern may be specified by designating acceleration. That is, the rolling speed is gradually increased at the front end portion of the rolled material 3, and the rolling speed is gradually decreased at the end portion of the rolled material 3, and the welding point (the connection point between the rolled material and the next rolled material). ) Is set to the minimum speed. In the middle of the rolled material 3, the rolling speed is the highest and substantially constant. In addition, when accelerating / decelerating a rolling speed, it has become clear from the past that a plate | board thickness deviation becomes large. This is greatly related to a change in the coefficient of friction between the rolling roll and the rolled material 3 during acceleration / deceleration.

Further, as shown in FIG. 1, when the rolled material 3 is accelerated or decelerated, an acceleration / deceleration compensator 13 for calculating an output correction amount with respect to the output of the sheet thickness tension controller 12, and a rolling control parameter for optimizing the rolling control parameter. And an optimization unit 7.
Specifically, as the output correction amount of the acceleration / deceleration compensation unit 13, the roll gap and the roll speed of each rolling stand 2 are adopted, and the acceleration / deceleration compensation unit 13 rolls according to the patterns shown in FIGS. Gap correction amount and roll speed correction amount are derived.
The rolling control parameter optimization unit 7 sets predetermined rolling control parameters such as an acceleration / deceleration compensation amount so that an evaluation function including a thickness deviation of the rolled material 3 at the time of acceleration and / or deceleration of the rolled material 3 becomes small. Has the ability to optimize. That is, optimization is performed using a rolling dynamic model capable of expressing the transient characteristics of rolling, and optimized rolling control parameters are output. At the time of optimization, a nonlinear optimization problem that minimizes the evaluation function is solved.

On the other hand, the rolling control parameter calculation device 1 according to the present invention includes a rolling state parameter optimization unit 8. In this rolling state parameter optimizing unit 8, in order to make accurate simulation when accelerating and / or decelerating the rolled material 3, the rolling load and / or roll gap in each rolling stand 2 is evaluated. The parameter relating to the friction coefficient and / or the parameter relating to the deformation resistance is optimally adjusted and calculated.
Specifically, when accelerating and / or decelerating the rolled material 3, the difference between the time change of the rolling load at the plurality of rolling stands 2 and the time change of the actual rolling load, and / or the plurality of rolling stands 2 The evaluation function including the difference between the time change of the actual roll gap and the time change of the actual roll gap is minimized. The reason for selecting the rolling load and roll gap as the evaluation function is that the plate thickness is easily affected by non-linearity (for example, dead band of tension) and the initial value of simulation, and it is difficult to reproduce actual rolling by simulation. However, the change in the rolling load and the roll gap is large and easy to reproduce, and it is easy to adjust the friction coefficient and deformation resistance parameters.

Here, as an example, a case where the friction coefficient is adjusted based on the difference in rolling load will be described. Considering the ease of adjustment, adjustment is made based on the data during deceleration.
As the friction coefficient model in the rolling state parameter optimization unit 8, for example, equations (10) and (11) are considered.

Here, α _i is a variable that defines the friction coefficient at a rolling speed of 0 in the #i rolling stand 2, and V _{out, i0} is an upper limit value of the rolling speed at which the friction coefficient changes. That is, if the rolling speed is faster than V _{out, i0} , the friction coefficient is assumed not to change with μ _i = μ _i0 . Here, μ _i0 is assumed to be accurate by identification based on data at a constant rolling speed, and is not included in the subsequent adjustment parameters.
For each rolling stand 2, α _i , V _{out, i0} are adjusted. In the case of a single stand, the adjustment is made with one stand. Also, μ _i0 can be adjusted as an unknown parameter simultaneously with α _i , V _{out, i0} .

First, the time history data of the rolling speed pattern held in the rolling speed pattern determining unit 14 is input to the rolling dynamic model unit 6. And, for example, α _i , V _{out, i0} of # 1 to # 4 rolling stand 2 are four ways of α _i = 0.5 _{, 0.7, 0.9, 1.1} , V _{out, i0} = 600, Assuming that three patterns of 800 and 1000 (mpm) can be taken, optimization is performed thereafter.
Further, the friction coefficient μ ₅ of the # 5 rolling stand 2 is expressed by the equation (11), and the friction coefficient μ ₅ is calculated.

As for α ₅ , V _{out, 50} , cμ ₅ of # 5 rolling stand 2, for example, α ₅ = _0.5 , 0.7, 0.9, 1.1, V _{out, 50} = 600, Assuming that three patterns of 800 and 1000 (mpm) and cμ ₅ = 2.0, 2.5, and 3.0 can be taken, optimization is performed thereafter. Therefore, the simulation is performed and optimized for the case of # 1 stand to # 4 stand and 4 × 3 = 12 ways and the # 5 stand is 4 × 3 × 3 = 36 ways.
By setting as in Expression (10) and Expression (11), it is possible to explicitly set the change in the friction coefficient at the time of deceleration and at the time of acceleration, and the finished plate thickness fluctuation can be reproduced more accurately. In addition, by using the accurately reproduced friction coefficient, the difference in roll gap at high speed and low speed can be set reliably, and the acceleration / deceleration compensation amount at low speed can be easily adjusted.

Next, an evaluation function for adjusting the friction coefficient will be described. The evaluation function J _err is expressed as follows.

Here, J _erri is a component of the evaluation function in the #i rolling stand 2.
In addition, when plate _{| board} thickness deviation can be utilized, it is good to set _Jerri as follows.

In this case, the thickness deviation can be directly evaluated.
In Expressions (13) and (14), w _pi and w _hi are weighting factors, and ΔP _{i _act} is the actual value of the change in rolling load from a constant speed before deceleration obtained from an actual rolling mill. , ΔP _{i — sim} is a change in rolling load from a constant speed before deceleration, obtained by calculation of the rolling dynamic model unit 6. Δh _{i _act} is the actual thickness change of the #i rolling stand 2 from the constant speed before deceleration, and Δh _{i _sim} is the constant speed before deceleration obtained by the calculation of the rolling dynamic model unit 6. This is the change in the thickness of the outlet side from the time.

t _s is the evaluation start time, and t _e is the evaluation end time. For example, as shown in FIG. 4, at the time of deceleration, t _s can be set as the start of deceleration, and t _e can be set as the time when the welding point between the rolled materials 3 starts to pass through the rolling stand 2 after the end of deceleration. .
Incidentally, if during acceleration, when the welding points between the strip 3 in the acceleration before starting the t _s is the time it has finished passing through the rolling stand 2, the rolling state becomes acceleration end after a fixed rate t _e has settled and can do.
The method described above is an example, and the present invention is not limited to this. For example, when evaluating at the time of acceleration and deceleration at the same time, an evaluation function can be obtained by adding an evaluation function for acceleration and an evaluation function for deceleration. In this case, since the time for evaluation increases, further improvement in accuracy of the rolling state parameter can be expected. In addition, the actual plate thickness includes not only those measured directly from the plate thickness meter but also those calculated from measured values such as mass flow plate thickness. Furthermore, the shape of the evaluation function is not limited Equation (12) to Formula (14), the difference between the calculated and actual values of the rolling load, i.e., contain P _i _ _act -P _i _ _sim It only has to be. The thickness is also a difference between the calculated and actual values of the thickness, i.e., it needs to include a _{h i _ act -h i _ sim} . For example, when P _{i _act} = P _{i _sim} at a constant speed, the parentheses in the equation (13) may be P _{i _act−} P _{i _sim} . For _{h i _ act = h i _} sim at a constant speed, the second term in the parentheses of formula (14) may be _{h i _ act -h i _ sim} .

The rolling control parameters are optimized and calculated using the rolling dynamic model based on the friction coefficient adjusted by the procedure described above.
In other words, the friction coefficient mu _i of the rolling condition parameter optimization unit 8 is calculated by applying the friction coefficient mu _i during rolling model equation, a rolling mill model section 4, the sheet thickness control model section 5, the rolling control parameter The optimized rolling control parameter is calculated by performing the calculation in the optimization unit 7.
FIG. 7 shows a flowchart of a method for adjusting a rolling state parameter such as a friction coefficient and a method for optimizing a rolling control parameter using the adjusted rolling state parameter in the present invention. Hereinafter, the case where the rolling state parameter is a friction coefficient will be exemplified and described. However, in the present invention, deformation resistance can be adopted as the rolling state parameter, and both the friction coefficient and deformation resistance can be adopted.

First, a value estimated or learned from actual rolling mill data is set as an initial value of rolling state parameters such as a friction coefficient. [S71]
Then, as a case-th calculation of # 1 rolling stand 2, the rolling mill model section 4, with a thickness control model section 5, based on the coefficient of friction is set at S71, from the time t _s until t _e Simulation of rolling is performed in the time including. [S72 to S74]
An evaluation function (formula (12)) is calculated based on the results obtained (rolling load, sheet thickness, roll gap, etc.). [S75]
Next, the rolling condition parameter optimization unit 8 determines the friction coefficient of the second case, performs the rolling simulation of the second case, and calculates the evaluation function. [S77, S73 to S75]
After calculating the evaluation function for all cases, the rolling state parameter optimization unit 8 determines the friction coefficient parameters (parameters related to the friction coefficient) α ₁ , V _{out, 10} that give the minimum evaluation function. And the parameter of the optimal friction coefficient used for the simulation for subsequent optimization is obtained. [S76, S78]
Similarly, a friction coefficient parameter is determined for the # 2 to # 5 rolling stands 2 in order, and a new friction coefficient is calculated. For the # 5 rolling stand 2, the friction coefficient parameters of α ₅ , V _{out, 50} , cμ ₅ are determined. [S79, S710, S73 to S78]
Thus, by performing optimization from the upstream side for each rolling stand, it is possible to accurately reproduce the influence of rolling load, sheet thickness, etc. from the upstream rolling stand 2 to the downstream rolling stand 2 due to the transfer of the rolled material, The accuracy of the obtained rolling state parameters is improved. In addition, the number of simulation cases is smaller in the case of discrete optimization than in the case of optimizing the rolling state parameters for all stands, and the convergence tends to be faster in the case of continuous optimization. There is also an effect that the calculation time of the conversion is shortened.

  Next, the end condition determination [S711] is made based on whether or not the friction coefficient parameters of the # 1 to # 5 rolling stands 2 have been adjusted at least twice. This is because when the upstream side is affected by the change in the friction coefficient of the downstream stand due to the influence of the tension or the control system configuration, the second adjustment will be optimized in consideration of the influence from the downstream side. It will be done and is effective. The end condition may be set when the parameter is no longer changed or when the parameter is less than the allowable value. When the change in the evaluation function becomes equal to or less than the allowable value or a predetermined number of times (a plurality of times), for example, the fifth parameter adjustment may be ended.

When the end condition is satisfied, it is assumed that the friction coefficient parameter has been determined. Based on this, the rolling simulation is performed using the rolling mill model unit 4, the plate thickness control model unit 5, and the rolling control parameter optimization unit 7. Perform optimization using. [S712]
Since the rolling control parameter obtained by the simulation of rolling takes into account the optimized friction coefficient in each rolling stand 2, the rolling material 3 can be obtained by applying this rolling control parameter to an actual rolling mill. The plate thickness accuracy can be improved without deteriorating the shape of the rolled material 3 during acceleration / deceleration. [S713]
In addition, by performing the rolling simulation described above, it is possible to obtain optimum rolling control parameters at the time of acceleration / deceleration of the rolled material 3 without performing an experiment using an actual rolling mill.

The optimization of the friction coefficient of the # 1 to # 5 rolling stands 2 may be performed not only on the discrete amount as described above but also on the continuous amount, and other optimizations besides the brute force method as described above A technique may be used. For example, heuristic techniques such as nonlinear programming, branch and bound, simulated annealing, genetic algorithm, etc. described in p8-p63 of “Optimum Design Handbook, Hiroshi Yamakawa, Asakura Shoten, 2003” may be used. .
FIG. 8 shows a case in which all friction parameters α _i , V _{out, i 0} , α ₅ , V _{out, 50} , cμ ₅ are set as continuous quantities and optimized using nonlinear programming such as sequential quadratic programming. A flowchart is shown.

As the evaluation function, Expressions (12) and (13) for evaluating the rolling load at all rolling stands 2, 2,... Are used.
First, a value estimated or learned from actual rolling mill data is set as the initial value of the friction coefficient. [S81]
Then, all the rolling stands 2, 2, about ..., using the set coefficient of friction, from time t _s to t _e, mill model section 4, the plate thickness control model section 5, the rolling control parameter optimization Using part 7, a rolling simulation is performed. [S82 to S84]
An evaluation function (formula (12)) is calculated based on the results obtained (rolling load, sheet thickness, roll gap, etc.). [S85]
It is determined whether or not the obtained evaluation function has converged to the minimum value. If it has not converged, the next friction coefficient is determined by the rolling state parameter optimizing unit 8, and the rolling simulation is performed again for evaluation. Calculate the function. [S87, S82 to S85]
When a known nonlinear optimization method such as sequential quadratic programming (SQP) is used, steps S35 to S87 are executed in an algorithm of a known nonlinear optimization method. In S87, a simulation may be performed to search for the next rolling state parameter.

When the obtained evaluation function has converged to the minimum value, the rolling mill model unit 4, the plate thickness control model unit 5, and the optimum rolling control parameters are based on the obtained friction coefficient parameters α _i , V _{out, i0.} A rolling simulation is performed using the conversion unit 7. [S89]
Since the rolling control parameters obtained by the rolling simulation take into account the adjustment of the friction coefficient in each rolling stand 2, the rolling control parameters can be applied to the rolling mill 3 by applying the rolling control parameters to an actual rolling mill. The plate thickness accuracy can be improved without deteriorating the shape of the rolled material 3 during deceleration. [S810]
On the other hand, when accelerating and / or decelerating the rolled material 3, the friction at each rolling stand 2 is minimized so that the difference between the time change of the roll gaps at the plurality of rolling stands 2 and the time change of the actual roll gaps is minimized. It is also possible to calculate the rolling control parameter using a rolling dynamic model in which the friction coefficient parameter related to the coefficient is optimized and the optimized friction coefficient parameter is incorporated.

In that case, the component J _erri of the evaluation function in the #i rolling stand 2 is _preferably expressed by the following equation.

  Moreover, about the rolling stand 2 which can measure or calculate plate | board thickness, you may make it like following Formula.

In equations (15) and (16), w _si and w _hi are weighting factors. Δs _i _ _act was obtained from the actual rolling mill, is the actual value of the roll gap change from the time of constant speed before the deceleration, Δs _i _ _sim is in the simulation, roll from the time of constant speed before the deceleration It is a gap change. Δh _{i _act} is the actual change in the delivery side thickness of the #i rolling stand 2 from the constant speed before deceleration, and Δh _{i _sim} is the change in the delivery side thickness from the constant speed before deceleration in the simulation. is there. t _s is the evaluation start time, and t _e is the evaluation end time. The form of the evaluation function is not limited to Expression (12), Expression (15), and Expression (16), and the difference between the calculated value of the roll gap and the actual value, that is, s _{i _act} −s. _i _ _sim may if it contains. For example, in the case of s _{i _act} = s _{i _sim} at a constant speed, the parentheses in the equations (15) and (16) may be set as s _{i _act} −s _{i _sim} .

  The evaluation function equations (13) and (14) and the evaluation function equations (15) and (16) can be used simultaneously. For example, “rolling load and roll gap” or “rolling load and roll gap and plate thickness” can be adopted for all the stands as components of the evaluation function for each rolling stand 2. "Rolling load and roll gap" are adopted, and in another rolling stand 2, "rolling load, roll gap and plate thickness" can be adopted. By adopting both the rolling load and the roll gap, the amount of information to be used is increased, and the accuracy of the optimized friction coefficient and deformation resistance is further improved.

Hereafter, the result of having performed the rolling simulation using the technique of this invention is shown.
FIG. 9 shows rolling performance data at the time of deceleration, which is a conventional example that does not employ the technique of the present invention. It can be seen that a rolling load deviation and a finished sheet thickness deviation occur during deceleration.
Using the performance data in FIG. 9 and the evaluation functions of the equations (12) and (14), 12 types are used for the # 1 to # 4 rolling stands 2 and 36 types are used for the # 5 rolling stand 2 in a discrete manner. The brute force method, which is a typical optimization calculation.
As a result, the following optimized coefficient of friction parameter was obtained.

・ Α ₁ = 0.5, V _{out, 10} = 600 (mpm)
・ Α ₂ = 0.5, V _{out, 20} = 600 (mpm)
・ Α ₃ = 0.9, V _{out, 30} = 600 (mpm)
・ Α ₄ = 1.1, V _{out, 40} = 800 (mpm)
Α ₅ = 0.7, V _{out, 50} = 1000 (mpm), cμ ₅ = 2.5

FIG. 10 shows a simulation result using the optimized coefficient of friction parameter, that is, a rolling simulation result to which the technique of the present invention is applied.

Comparing FIG. 9 and FIG. 10, it can be seen that the friction coefficient parameter is adjusted so that the actual rolling load deviation (FIG. 9 (b)) and the simulation (FIG. 10 (b)) substantially coincide. With respect to the finish plate thickness deviation, the peak occurrence time of the plate thickness variation in the finish plate thickness deviation record (FIG. 9 (c)) and the simulation (FIG. 10 (c)) is almost the same. In consideration of disturbances such as noise, it can be confirmed that the peak values are almost the same.
Next, using the optimized friction coefficient parameter, the roll gap acceleration / deceleration compensation amount of the # 5 rolling stand 2 is optimized as a rolling control parameter. In the present embodiment, the method of changing the roll speed acceleration / deceleration compensation amount of the # 5 rolling stand 2 is not elaborated, but the roll gap acceleration / deceleration is added by adding the roll speed acceleration / deceleration compensation amount to the optimization variable. It can be optimized in the same way as the compensation amount.

The evaluation function J _err ′ is defined as in Expression (17).

In Expression (17), Δh _{5 _sim} is the change in the exit side plate thickness of the # 5 rolling stand 2 from the constant speed before deceleration calculated by the rolling dynamic model unit 6 as described above, that is, the finish plate thickness It is a change. t _s is the evaluation start time, and t _e is the evaluation end time. For example, as in the optimization of the rolling state parameter, as shown in FIG. 4, at the time of deceleration, t _s is set at the start of deceleration, and t _e is the welding point between the rolled materials 3 after the completion of deceleration at the rolling stand 2. It can be when it begins to pass. At the time of acceleration, t _s is the time when the welding point between the rolled materials 3 before the start of acceleration has finished passing through the rolling stand 2, and t _e is a constant speed after the end of acceleration, and the rolling state is stabilized (becomes constant). It can be time).

As an example, the acceleration / deceleration compensation amount of the roll gap of the # 5 rolling stand 2 is determined by the following equation.

_{Vout, 5} ≦ 100 (mpm): Δs ₅ = Δs ₅₀
・ 100 ≦ V _{out, 5} ≦ V _{out, 50} :
Δs ₅ = Δs ₅₀ · (V _{out, 5} −V _{out, 50} ) ² / (V _{out, 50} −100) ²
・ V _{out, 50} ≦ V _{out, 5} : Δs ₅ = 0

Two parameters of Δs ₅₀ and V _{out, 50} are rolling control parameters to be optimized.

As a simple example, discrete optimization is performed in two ways: two types of Δs ₅₀ = −60, −120 (μm) and two types of V _{out, 50} = 600,800 (μm).
By calculating the evaluation function using the brute force method, a solution of Δs ₅₀ = −120 (μm) and V _{out, 50} = 800 (μm) was obtained.
FIG. 11 shows the result of rolling simulation using the rolling control parameters Δs ₅₀ and V _{out, 50} optimized as described above. From the comparison between FIG. 10 and FIG. 11, it is clear that the plate thickness variation during deceleration is halved.

As described above, the rolling control parameter calculation method, calculation apparatus, and rolling simulation apparatus according to the present invention are not limited to the above-described embodiments.
That is, although the rolling mill 9 has been described by exemplifying the one having the # 1 to # 5 rolling stands 2, the number of the rolling stands 2 is not limited to this and can be applied to a single stand mill such as a reverse mill. is there. Further, the rolling form is not limited to cold rolling, and is applicable to hot rolling.
Moreover, in the case of this embodiment, although the parameter regarding the friction coefficient in each rolling stand 2 was adjusted, you may make it adjust the parameter regarding deformation resistance. For example, as described above, any one of formulas (7.51) to (7.53) disclosed in p188 to 189 of "Theory and practice of plate rolling, edited by Japan Iron and Steel Institute, 1984" is used. And let the deformation resistance be k _i _ _nominal . And as a deformation resistance model when adjusting the deformation resistance, for example,

k _i = k _i _ _nominal · (β1 _i + β2 · V _{out, i} )

Can be used (where β1 _i and β2 are rolling state parameters to be adjusted).

It is also possible to simultaneously optimize the parameter relating to the deformation resistance and the friction coefficient parameter. In this case, the parameter to be adjusted increases and finer adjustment is possible, so that the accuracy of the rolling dynamic model can be increased.
Further, the form of the evaluation function is not limited to Expression (12) to Expression (16), and an individual evaluation function may be adopted for each rolling stand.

It is a block diagram of the calculation apparatus of a rolling control parameter, and a rolling simulation apparatus. It is a schematic diagram of the rolling mill which the rolling mill model part has modeled. It is the figure which showed the input / output of the plate | board thickness tension control part. It is the figure which showed the rolling speed pattern in a # 5 rolling stand. It is the figure which showed the correction amount (acceleration / deceleration compensation) of the roll gap. It is the figure which showed the correction amount (acceleration / deceleration compensation) of roll speed. It is a calculation flowchart in the calculation apparatus of a rolling control parameter, and a rolling simulation apparatus (in the case of a discrete amount). It is a calculation flowchart in the calculation apparatus of a rolling control parameter, and a rolling simulation apparatus (in the case of continuous quantity). It is the figure which showed the rolling performance (conventional example). It is a figure which shows the result of having simulated the rolling condition using the optimized friction coefficient. It is a figure which shows the result of having simulated the rolling condition using the optimized acceleration / deceleration compensation amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rolling control parameter calculation apparatus 2 Rolling stand 3 Rolled material 4 Rolling mill model part 5 Sheet thickness control model part 6 Rolling dynamic model part 7 Rolling control parameter optimization part 8 Rolling state parameter optimization part 9 Rolling machine 10 Target plate Thickness setting unit 11 Target tension setting unit 12 Plate thickness tension control unit 13 Acceleration / deceleration compensation unit 14 Rolling speed pattern determination unit

Claims (6)

Build a rolling dynamic model that dynamically expresses a rolled material, a plurality of rolling stands for rolling the rolled material, and a control system for controlling the thickness of the rolling stand,
Evaluation including the difference between the calculated value and the actual value in the rolling dynamic model with respect to the time change of the rolling load and / or the time change of the roll gap at the rolling stand at the time of acceleration and / or deceleration of the rolled material. Optimize parameters related to coefficient of friction and / or deformation resistance at each rolling stand so that the function is minimized,
Optimizing rolling control parameters including the setting parameters of the plate thickness control and / or the setting parameters of the rolling stand using the rolling dynamic model incorporating the parameters relating to the optimized coefficient of friction and / or parameters relating to deformation resistance A method for calculating a rolling control parameter, characterized by:   The calculation method of the rolling control parameter according to claim 1, wherein calculation of optimization of the parameter relating to the friction coefficient and / or the parameter relating to deformation resistance is sequentially performed from the upstream rolling stand to the downstream rolling stand. .   The calculation method of the rolling control parameter according to claim 1 or 2, wherein the calculation of the parameter relating to the friction coefficient and / or the parameter relating to the deformation resistance is performed once or plural times for each rolling stand.   The parameter relating to the friction coefficient includes an upper limit rolling speed that is an upper limit rolling speed at which the friction coefficient does not change, and a variable that defines a friction coefficient at a rolling speed of 0. 4. A method for calculating a rolling control parameter according to any one of 3 above. A rolling mill model unit that models a rolled material and a plurality of rolling stands that roll the rolled material, and a rolling dynamic model unit that includes a plate thickness control model unit that controls the plate thickness of the rolling stand,
Regarding the time change of the rolling load and / or the time change of the roll gap in the rolling stand at the time of acceleration and / or deceleration of the rolled material, the difference between the calculated value and the actual value in the rolling dynamic model part is included. A rolling state parameter optimizing unit that optimizes a parameter relating to a coefficient of friction and / or a parameter relating to deformation resistance in each rolling stand so as to minimize the evaluation function;
Using the rolling dynamic model unit in which the parameters relating to the friction coefficient and / or the parameters relating to deformation resistance optimized by the rolling state parameter optimizing unit are incorporated, the setting parameters for the plate thickness control and / or the rolling stand A rolling control parameter optimization unit that optimizes and calculates rolling control parameters including setting parameters;
An apparatus for calculating a rolling control parameter, comprising: A rolling mill model unit that models a rolled material and a plurality of rolling stands that roll the rolled material, and a rolling dynamic model unit that includes a thickness control model unit that controls the thickness of the rolling stand,
Regarding the time change of the rolling load and / or the time change of the roll gap in the rolling stand at the time of acceleration and / or deceleration of the rolled material, the difference between the calculated value and the actual value in the rolling dynamic model part is included. A rolling state parameter optimizing unit that optimizes a parameter related to a coefficient of friction and / or a parameter related to deformation resistance in each rolling stand so that the evaluation function is minimized;
Using the rolling dynamic model unit in which the parameters relating to the friction coefficient and / or the parameters relating to deformation resistance optimized by the rolling state parameter optimizing unit are incorporated, the setting parameters for the plate thickness control and / or the rolling stand A rolling control parameter optimization unit that optimizes and calculates rolling control parameters including setting parameters, and
The rolling dynamic model unit uses the parameters related to the friction coefficient and / or the deformation resistance optimized by the rolling state parameter optimization unit and the rolling control parameters optimized by the rolling control parameter optimization unit. A rolling simulation apparatus characterized by being configured to reproduce a rolling situation.

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