JP2755893B2 - Rolling control method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a rolling mill, and more particularly to a system for performing a simulation between a pre-process and a post-process so as to optimally control the post-process.

[0002]

2. Description of the Related Art For example, a plate rolling computer control system controls a heating furnace, a rough rolling mill, a finishing rolling mill, a cooling device, a hot leveler, etc., and controls the schedule of the entire system and the input / output of each process every time a product is changed. Schedule calculation device for determining the material dimensions on the side, set-up calculation device for determining the control command (target value) of the control device of each process based on the schedule calculation, and DDC for controlling the control target according to the given control command It is hierarchically configured with a control device.

[0003] The control gain of a DDC, such as a thickness control device or a shape control device, is calculated by a setup based on the product size and material of the material to be rolled, the nominal thickness, width and temperature of the material to be rolled in the previous process. Is determined by

[0004] However, actual rolling data includes disturbance generated in a previous process, and is not a uniform value like a nominal value. For example, the dimensions and temperature of the material after the rough rolling in the hot rolling mill have deviations from the nominal values, which are disturbances in the finish rolling in the post-process and reduce the control accuracy. Therefore,
The control gain is tuned by performing some rolling.

On the other hand, as a simulation in a rolling control system, as described in Japanese Patent Application Laid-Open No. 61-231607, a test computer is developed by asynchronously receiving actual data from an online computer that performs rolling control. Some simulations are executed by an application program in the middle and debugging is performed in real time in a real process. Alternatively, JP-A-59-1215
As described in Japanese Patent Publication No. 01, actual process data from a process control computer is stored online, the data being stored is output during simulation, a simulation is performed by the process control computer, and a test for reproducing a control device trouble is performed. There are things to do.

[0006]

The demands of the market these days are:
We demand higher quality for the quality and yield of rolled material. However, in the prior art, even if the control gain is adjusted by a number of actual rollings as described above, the disturbance in the previous process is not reproducible, so that it is not optimal for each plate, and this is not possible. This is one of the factors that lowers the accuracy.

Further, the conventional simulation in the rolling control is limited to debugging of a control program or a test of a failure of a control device, and there is no simulation that directly reflects a simulation result in online control, particularly in DDC control.

It is an object of the present invention to provide a control method and apparatus which overcome the problems of the prior art and optimize a control gain in a post-process by on-line simulation considering a disturbance generated in a pre-process. .

[0009]

SUMMARY OF THE INVENTION A rolling control method according to the present invention provides a model simulating the post-process in which a control gain is given as a parameter during a period in which a material to be rolled moves from a predetermined pre-process to a predetermined post-process. Accordingly, the simulation is performed based on the data of the material to be rolled after the pre-process, and the post-process is controlled by determining the control gain that optimizes the result.

The rolling control device of the present invention is a rolling control device for a finishing rolling mill connected to a rough rolling mill by an on-line transfer means, wherein process data of a material to be rolled after rough rolling is sampled at predetermined intervals in a longitudinal direction. Measuring device, process data storage means for storing the measured process data in time series, parameter storage means for storing a plurality of control gains, a control target value which is a setup calculation value and the control gain is given, A finish rolling model that simulates a change in a material to be rolled by the finish rolling based on the process data at the sampling point, evaluates a simulation result by each of the control gains, selects an optimal control gain, and sets the optimal control gain in the rolling control device. A simulator having evaluation means.

[0011]

The rolling control method according to the present invention measures the process data including the disturbance generated in the preceding process during the transition from the preceding process to the succeeding process, and simulates the model by directly giving the measurement results to a model simulating the succeeding process. The control gain at which the result is optimal is determined for each rolled material.

As described above, by performing a simulation with the nonlinearity, the accuracy is higher when sufficient data for simulation can be obtained, compared to a conventional method in which a control system is formed by approximating a nonlinear phenomenon. In the present invention, actual data over the entire length of the material to be rolled is obtained by utilizing the travel time between processes, and a highly accurate simulation is possible.

According to the present invention, the DDC in the post-process can be performed by performing the online simulation.
Is optimized for each material to be rolled, so that the product quality and yield in the rolling system can be greatly improved.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration in which a rolling mill control system according to the present invention is applied to a hot rolling process including a rough rolling mill 4 and a finishing rolling mill 5. The rolled material 8 that has completed the rough rolling step is transferred to the finishing mill 5 by the transfer table 9.

The setup computer 3 receives a target value of the material dimensions at the entrance and exit of the finishing step from a rolling schedule calculator (not shown), which is performed each time a product is changed, such as material and dimensions. The control command value of the speed and the tension between stands is determined and set in the thickness control device 2 for finish rolling.

The thickness control device 2 includes a pressing position control unit for controlling the pressing device 6, a speed control unit for controlling the roll speed, a position control unit for controlling the looper, a tension control unit related to the speed control unit and the position control unit. The thickness control of the finishing mill 5 is executed by a control command from the setup computer 3 and a control gain from the simulator 1.

For example, the rolling position control unit obtains a rolling amount of each stand from the setup computer based on a target plate thickness set for each stand and an actually measured sheet thickness at the outlet side. Control to position. Hereinafter, an example of the rolling position control unit will be mainly described.

The simulator 1 includes a finish rolling model simulating a rolling phenomenon, an actuator operation, and a control operation of the finishing mill 5, and each of the rolled materials 8 after rough rolling is measured online by the measuring device 7 over the entire length of the rolled material 8. For the sheet thickness at a point, simulation of finish rolling is performed while changing the control gain for the same rolled material, and the control gain of the sheet thickness control device 2 is optimized for each rolled material based on the evaluation. This process ends before the finish rolling of the target rolled material 8.

In addition, the sheet thickness may use a measured value on the exit side of the final pass in the rough rolling step. Also, in FIG. 1, the simulator 1 and the rolling control device 2 have different configurations,
The simulator 1 may be incorporated in the rolling control device 2.

FIG. 2 is a functional block diagram showing a detailed configuration of the simulator 1. The measurement value storage means 11 stores the sheet thickness of each rolling point at a predetermined period (for example, 1 msec) for one rolled material.

The set-up section 12 calculates the same control command for the distribution of each stand as is given to the sheet thickness control device 2 based on the target dimensions from the host. In this case, the average plate thickness or the nominal value based on the measured values after the rough rolling is defined as the entry-side plate thickness.
However, if the setup computer 3 can use the control command in timing, the setup unit 12 can be omitted.

The finish rolling model 13 includes the setup unit 1
Based on the control command value initially set from Step 2, a simulation is executed for the change after finish rolling based on the stored thickness at each sampling point, using the control gain of the control gain table 15 as a parameter. Storage means 1
Reference numeral 4 stores, for each control gain, the predicted thickness of one sheet after finish rolling as a simulation result.

The control gain table 15 stores a plurality of control gains (sets) of the thickness control system which are determined in advance based on actual results. The evaluation means 16 calculates the simulation result as an average plate thickness deviation, a maximum plate thickness deviation, a plate end plate thickness deviation,
Evaluate according to predetermined evaluation criteria such as tension limit,
A control gain (set) for obtaining the optimum evaluation is determined and set in the sheet thickness control device 2 which is an actual machine. In this embodiment, the average thickness deviation is used.

FIG. 3 is a flowchart showing the processing procedure of the simulator 3. This process is performed for each rolled material every time, is started after the end of the rough rolling step, and ends before the finish rolling is started (before the finishing rolling mill is engaged).

In step s101, the sheet thickness data sampled by the measuring device 7 at a predetermined cycle is
Are stored in chronological order over the entire length of.

In step s102, the actual value (average value) of the thickness data after the rough rolling is performed in order to roll the steel sheet to a thickness corresponding to the finish rolling target value given each time the rolling schedule is changed.
, A target value for each stand of the plate thickness control device is calculated, and this is set as a control command for the model 13. In the case where the control target value by the setup computer 3 is directly used, this step is omitted.

In step s103, a set of control gains is read from the control gain table 15 and set in the model 13. A plurality of sets of control gains for each loop of the rolling-down position control system are stored in advance, each set including a Visla AGC, a feedforward (FF) AGC, and a monitor AGC. Each set of these control gains is determined by, for example, a past actual value tuned for each product or a learning value by the simulation of the present example.

In step s104, the stored thickness data of each sampling point is sequentially input, and the rolling state of each stand of the finishing mill 5 is simulated one after another. Predict plate thickness. Note that the sampling cycle after rough rolling for actually measuring the sheet thickness and the sampling cycle on the exit side of each stand in the simulation are usually set to be the same.

In step s105, the simulation result of each sampling point on the final set-up side for one rolled material is stored. In step s106, the control gains (sets) stored in the table 15 are stored in steps s103 to s103.
Repeat s105. Steps S103 and S104
Is started as soon as a part of the sampled data of the material to be rolled is obtained by starting the processing of S101, and the processing time of the simulation is reduced. This processing time is a multiple CP
It is also possible to further reduce the length by parallel processing of a plurality of gains by U.

In step s107, for each control gain (set), the deviation between the target plate thickness value and the plate thickness at each sampling point of the simulation result is obtained, and the average plate thickness deviation for one rolled material is obtained from this. In s108, the control gain (set) that minimizes the average thickness deviation is selected from the table 15 and output as the control gain of the actual machine.

In this way, the optimum control gain for the rolled material is determined by simulation based on the actual data after the rough rolling process, and the actual thickness control device 2 is used.
, And thereafter the finish rolling step is started. By performing this on-line for each rolled material after the rough rolling, finish rolling can be performed in consideration of disturbance generated in the rough rolling process.

Next, the configuration and operation of the finish rolling model 13 will be described. FIG. 4 shows a detailed configuration of the model 13, and the same elements as those in FIG. Model 13 is a divided model 13-1 to 13 corresponding to each stand of finishing mill 5.
13-5, each divided model is composed of rolled material models 101-501, rolling device models 102-502, and rolling control device models 103-503.

When the sheet thickness after rough rolling is input from the storage means 11, the rolled material model 101 is expressed by the following rolling load equation (Equation 1), flat roll equation (Equation 2), and gauge meter equation (Equation 3).
New The simultaneous solution - obtained by Tonrapuson method to obtain a plate thickness h ₁ out.

[0035]

P = b · km · Dp√ (R ′ (H−h)) (1) Dp = a ₁ −a ₂ r + a ₃ μr√ (1−r) √ (R ′ / h) (2) b: plate width Km: deformation resistance Dp: friction correction term R ': flat roll radius r: reduction ratio ((H-h) / H) μ: friction coefficient

[0036]

R ′ = R (1 + CP / (b (H−h))) (3) C = 16 (1−ν ² ) / πE (4) ν: Poisson's ratio E: Young's modulus

[0037]

H = S + P / K (5) K: Mill Spring Constant Here, the gap S between the rolls in (Equation 3) is calculated from the drafting device model 102 shown in FIG. That is, the gap S is obtained as a function of the primary delay and the dead time of the rolling-down device with respect to the rolling-down command Sp.

The first stand pressure reduction command Sp ₁ is set to the stand entry side sheet thickness H ₁ (measured sheet thickness at each point after rough rolling) so that the target exit sheet thickness hp ₁ which is a control command from the setup unit 12 is obtained. ), The rolling load P ₁ by the setup computer 3 and the like are given, and the rolling load P _{1 is} calculated by the rolling control model 103.

FIG. 6 shows the configuration of the rolling reduction control device model.
The control gains of the respective loops in the figure, that is, the gains of the viscera α, the feedforward G _FF , the monitor integral G _I , the stand monitor proportional G _p , and the stand monitor integral R _S are:
Each set is given as a parameter from the control gain table 15. In the figure, the suffix i represents the stand number of the finishing mill 5, the suffix o represents the setup value, K represents the steel properties of the mill, Ttrans represents the material transfer time between stands, and δ represents the influence coefficient.

The rolling results (delivery side thickness) h ₁ of the sampling point by the first stand model 13-1 is input as a stand thickness at entrance side of H ₂ rolled material model 201 of the second stand model 13-2 You. In this way,
Is implemented computed by each stage model, the thickness predicted value h ₅ of each sampling point over the rolled material entire length of rolled material model 501 of the fifth stand is calculated. The predicted thickness value over the entire length is repeatedly obtained using the control gain as a parameter, and is stored in the storage unit 14 for each gain.

FIG. 7 shows the results of a simulation under the conditions shown in Table 1 according to this embodiment.

[0042]

[Table 1]

FIG. 7A shows the thickness (predicted value) of the rolled material in the length direction in three cases in which the control gain is used as a parameter. FIG. 11B shows the average value of the deviation from the target value (3.0 mm) in each case. In this example, the control gain of Case 3 having the smallest deviation is selected.

As described above, according to this embodiment,
After rough rolling and before finish rolling, based on the thickness measured for the target rolled material, the thickness change when the rolled material is finish rolled is predicted by a simulator with the control gain as a parameter, and from the results. Since the optimal control gain is set in the actual thickness control device, high-precision control that takes into account disturbance due to rough rolling is possible, and tuning by actual rolling is not required, and the yield of materials is improved. I do.

In the above-described embodiment, the drafting device of the plate thickness control device has been mainly described. However, a simulation can be similarly performed for a tension control system and a speed control system for a roll driving device.

Further, the present invention is not limited to controlling the thickness.
The same can be applied to finish rolling shape control and finish rolling temperature control. In the former case, based on measured values such as the profile of the sheet after rough rolling, the shape over the entire length of the rolled material after finish rolling is simulated with the control gain as a parameter, and the control gain that gives the optimum simulation result is set to the actual machine. Set in the shape control device.

In the latter case, the sheet temperature over the entire length of the rolled material after finish rolling is simulated using the control gain as a parameter based on the measured values such as the rolled material temperature after rough rolling, and control is performed to give an optimum simulation result. Set the gain in the actual temperature controller.

Thus, high-precision control can be realized in consideration of disturbance due to the rough rolling step, and the quality accuracy of the finished rolled material can be further improved.

[0049]

According to the present invention, an on-line simulation is performed based on actual data including disturbance in the preceding process, and the control gain of the DDC in the subsequent process is reduced to 1
Since the optimization is performed for each roll, product quality and yield in the rolling system can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a rolling control system according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing a configuration of a simulator.

FIG. 3 is a flowchart showing a processing operation of the simulator.

FIG. 4 is a functional block diagram showing a configuration of a finish rolling model.

FIG. 5 is a block diagram showing a model of a drafting device.

FIG. 6 is a block diagram showing a model of a rolling-down control device.

FIG. 7 is an explanatory diagram illustrating a simulation result.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Simulator, 2 ... Sheet thickness control device, 3 ... Setup computer, 4 ... Rough rolling machine, 5 ... Finish rolling machine, 6 ... Roll-down device, 7 ... Measuring device, 8 ... Material to be rolled, 11 ... Measured value storage means , 12 ... setup means, 13 ... finish rolling model,
13-1: first stand model, 15: control gain table, 16: evaluation means, 101: rolled material model, 102
... Roll-down device model, 103 ... Roll-down control device model.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B21B 37/00 B21B 37/18-37/20

Claims (5)

(57) [Claims] 1. During a period in which a material to be rolled moves from a predetermined preceding process to a predetermined subsequent process, data of the material to be rolled after the preceding process is obtained by a model simulating the latter process in which a control gain is given as a parameter. A rolling control method that performs a simulation based on the results, determines a control gain that optimizes the result, and controls the post-process. 2. A rolling control method for a rolling equipment in which a pre-process and a post-process of a rolling process are connected online, wherein process data of a material to be rolled is processed during a period from the end of the pre-process to the start of the post-process for each material to be rolled. Measurement is performed in the length direction at a predetermined cycle, and a simulation using a model simulating the post-process based on the process data of each cycle is repeatedly performed using a control gain as a parameter, and an optimal simulation result that satisfies a predetermined evaluation criterion is obtained. Wherein the control gain is selected and used for the predetermined control in the post-process. 3. A rolling control method in which a material to be rolled after a rough rolling step moves online and proceeds to a finish rolling step, wherein the material to be rolled is moved from the end of the rough rolling step to the time before the start of the finish rolling step for each material to be rolled. The thickness of the rolled material is measured in the length direction at a predetermined cycle, and the change over the entire length of the material to be rolled by finish rolling is simulated by a model simulating the finish rolling step based on the thickness of each cycle, The simulation is repeatedly executed using the control gain as a parameter, a control gain obtained as an optimal simulation result satisfying a predetermined evaluation criterion is selected, and the control gain is used for controlling the thickness of the finish rolling process. Rolling control method. 4. The rolled material according to claim 3, wherein the predetermined evaluation criterion is determined over the entire length of the rolled material, which is obtained from a deviation between a target plate thickness of the rolled material given in advance and a thickness at each sampling point by the simulation. A rolling control method characterized in that the average deviation or deviation width is the smallest. 5. A rough rolling mill connected with an on-line transfer means.
In the rolling control device of the finishing mill, the process data of the material to be rolled after the rough rolling is determined in the longitudinal direction.
A measuring device that samples periodically, and a process that stores measured process data in time series
Data storage means, parameters for storing a plurality of control gains
Data storage means, control target values,
And the control gain are given.
Changes in the material to be rolled by the finish rolling based on process data
Finishing rolling model to simulate
Evaluate the simulation result by gain to optimize
Evaluation means for selecting the control gain and setting the gain in the rolling control device
Rolling, comprising a simulator having
Control device .