EP2566633B1 - Operating method for a production line with prediction of the command speed - Google Patents

Description

• wobei einem Steuerrechner für die Fertigstraße spätestens zu einem Zeitpunkt, zu dem ein erster Bandpunkt des Bandes sich noch vor der Fertigstraße befindet, für den ersten Bandpunkt eine Istgröße und eine Sollgröße bekannt sind,
• wobei die Istgröße für den Ist-Energieinhalt des ersten Bandpunktes und Sollgröße für den Soll-Energieinhalt des ersten Bandpunktes charakteristisch sind,
• wobei die Istgröße auf einen Ort vor der Fertigstraße bezogen ist und die Sollgröße auf einen Ort hinter der Fertigstraße bezogen ist,
• wobei der Steuerrechner vor dem Einlaufen des ersten Bandpunktes in die Fertigstraße für den ersten Bandpunkt anhand einer Ermittlungsvorschrift eine Leitgröße ermittelt,
• wobei die Leitgröße dafür charakteristisch ist, mit welcher Leitgeschwindigkeit der Steuerrechner die Fertigstraße zum Zeitpunkt des Einlaufens des ersten Bandpunktes in die Fertigstraße betreibt,
• wobei der Steuerrechner anhand der Leitgröße die Leitgeschwindigkeit ermittelt und die Fertigstraße zum Zeitpunkt des Einlaufens des ersten Bandpunktes in die Fertigstraße mit der Leitgeschwindigkeit betreibt,
• wobei in die Ermittlungsvorschrift für die Leitgröße die Istgröße und die Sollgröße des in die Fertigstraße eintretenden Bandpunktes eingehen.

The present invention relates to an operating method for a finishing train for rolling a strip,

• wherein a control computer for the finishing train, at the latest at a time at which a first band point of the band is still in front of the finishing train, for the first band point, an actual size and a nominal size are known,
• the actual size being characteristic of the actual energy content of the first band point and nominal size of the target energy content of the first band point,
• wherein the actual size is related to a location in front of the finishing train and the target size is related to a location behind the finishing train,
• wherein the control computer ascertains a reference variable before the first band point enters the finishing train for the first band point on the basis of a determination rule,
• the guide variable being characteristic of the rate at which the control computer operates the finishing train at the time of entry of the first strip point into the finishing train,
• wherein the control computer determines the guide speed on the basis of the guide variable and operates the finishing train at the time of the entry of the first strip point into the finishing train at the guide speed,
• wherein the actual size and the nominal size of the strip point entering the finishing line are included in the determination rule for the guide variable.

The present invention further relates to a computer program comprising machine code which is directly executable by a control computer for a finishing train for rolling a strip and whose execution by the control computer causes the control computer to operate the finishing train according to such an operating method.

The present invention further relates to a control computer for a finishing train for rolling a belt, wherein the control computer is configured to operate the finishing train according to such an operating method.

The present invention further relates to a finishing train for rolling a belt equipped with such a control computer.

The above items are for example from the US Pat. No. 6,220,067 B1 known.

Out WO-A 03/045599 is a generic method known.

As a rule, a hot strip mill consists of at least one finishing train and one downstream of the finishing train cooling section. Optionally, the finishing train may be preceded by a roughing train - alternatively or in addition to the cooling section - or the finishing train may be preceded by a casting device.

The finishing train has a number of rolling stands. The number of rolling stands can be determined as needed. As a rule, there are several rolling stands, for example four to seven rolling stands. In individual cases, however, only a single rolling stand can be present. For each roll stand - regardless of their number - a setpoint decrease is specified for every rolling pass to be performed. If several rolling stands are available, generally further input and / or outlet-side desired trains are specified. If only a single roll stand is present, input and / or outlet side predetermined tension can be specified. However, this is not mandatory.

One of the targets to be met on a hot strip mill is the final rolling temperature, that is, the temperature at which the strip exits the finishing train. Alternatively to the final rolling temperature, another variable describing the energy content of the strip at this location may also be used used, for example, the enthalpy. The target size should be kept as far as possible over the entire length of the tape. The target size may alternatively be constant or vary along the length of the band.

To achieve the target size, the guide speed of the finishing train is usually adjusted accordingly. The guide speed is a speed, from which - possibly in conjunction with the to be set in the finishing line Stichabtnahmen and Sollzügen - the occurring within the finishing line strip and roller peripheral velocities are clearly determined. For example, it may be a fictitious speed of the tape head or the speed of the first rolling stand of the finishing train. The guide speed can be defined, for example, as a function as a location of the tape head.

Intermediate stand cooling devices and / or an induction furnace arranged upstream of the finishing train may optionally be present as further actuators. These actuators act - as well as cooling devices of the cooling section - only locally on the tape. In the context of the present invention, however, the presence of these other actuators is of minor importance. Crucial factors are the conduction velocity (or a variable which is characteristic of the conduction velocity, for example the mass flow) and their determination.

As already mentioned, the finishing train is usually arranged downstream of a cooling section. In the cooling section, the strip is cooled in a defined manner to a reel temperature (or enthalpy). The speed at which the belt passes through the cooling section is determined by the guide speed. The adjustment of the required for the individual band points Abkühlverläufe carried out in that the tape points are tracked away and control valves of the cooling devices of the cooling section, which adjust the flow of coolant flow, are controlled in a timely manner.

The control valves have in practice considerable delay times, which are often in the order of several seconds. In order to be able to control the control valves in good time, it is therefore necessary to be on time knowing in advance when a certain band point is within the control of a particular cooling device. In order to calculate exactly when a certain band point enters this influence area and when it exits from it, it is necessary to know not only the instantaneous value of the master speed, but also the future course of the master speed, at least within the delay time of the control valves. In addition, the cycle time as such, ie the time required by the respective band point for passing through the cooling section, also influences the reel temperature. The cycle time is - of course - influenced by the course of the conduction velocity.

In the prior art it is known to determine the Leitgeschwindigkeitsverlauf in a simplified manner. For example, an initial value is specified with which the tape head is to pass through the finishing train. Furthermore, an acceleration ramp is specified, via which the belt is accelerated to a final speed as soon as the tape head has left the finishing train. In practice, this procedure proves to be unsuitable for maintaining a predetermined desired final rolling temperature (or a corresponding temperature profile) with high accuracy.

It is also known in the prior art to detect the (actual) final rolling temperature and to track the guide speed in the sense of minimizing the deviation of the actual final rolling temperature from the predetermined target end rolling temperature. This tracking can by means of a classic or - as in the DE 103 21 791 A1 described - done by means of a model predictive control. Regardless of the type of control (classic or model predictive), the control intervention, ie changing the conduction velocity, but simultaneously to determine the conduction velocity. Any prediction is limited - analogous to the unregulated procedure - to the specification of a future expected acceleration ramp. Whether on reason the set and actual sizes of the next control step is actually assumed the predicted conduction velocity is not certain. Furthermore, the prediction systematically extends to a single control step.

Although in practice this procedure usually proves to be suitable for maintaining a predetermined desired final rolling temperature (or a corresponding course) with high accuracy. However, in this approach, it is not predictable in which direction and by which value the conduction velocity will actually vary in the next control step. The possible prediction is more of a guess than a real determination.

Moreover, prediction, even if correct or at least approximately correct, would be in the teaching of DE 103 21 791 A1 limited in principle to a single control step. This would be completely insufficient for a timely tracking of the control signals for the actuators of the cooling section or of the intermediate structure cooling devices of the finishing train. Therefore, varying the conduction velocity results in the quantities of coolant applied by the actuators of the cooling section not being applied to the band points for which the quantities of coolant were previously calculated. Therefore, deviations of the temperature (or of the energy content) of the band points at the end of the cooling section (for example on a reel) from desired nominal values result. The exact compliance with the final rolling temperature is therefore "bought" in the prior art with an increased fluctuation, for example, of the coiler temperature.

In the older European patent application, not yet published on the filing date of the present invention 09 171 068.1 (Filing date 23.09.2009) describes a model predictive control, which regulates a finishing train and a cooling section together by means of a forecast. Here also the mass flow is predicted. This approach requires coolant quantities output by actuators of the cooling section, to determine the mass flow. Furthermore, the mass flow is always readjusted immediately. Therefore, this approach does not solve the problem of reliably determining a conduction velocity history in advance.

• wobei einem Steuerrechner für die Fertigstraße spätestens zu einem Zeitpunkt, zu dem ein erster Bandpunkt des Bandes sich noch vor der Fertigstraße befindet, für den ersten Bandpunkt und eine Anzahl von dritten Bandpunkten des Bandes jeweils eine Istgröße und eine Sollgröße bekannt sind,
• wobei für jeden Bandpunkt die jeweilige Istgröße für den Ist-Energieinhalt des jeweiligen Bandpunktes und die jeweilige Sollgröße für den Sollenergieinhalt des jeweiligen Bandpunktes charakteristisch sind,
• wobei für jeden Bandpunkt die jeweilige Istgröße auf einen Ort vor der Fertigstraße bezogen ist und die jeweilige Sollgröße auf einen Ort hinter der Fertigstraße bezogen ist,
• wobei die dritten Bandpunkte vor dem ersten Bandpunkt in die Fertigstraße einlaufen.

From the WO 03/045 599 A1 an operating method for a finishing train for rolling a strip is known

• wherein a control computer for the finishing train is known at the latest at a time at which a first band point of the band is still in front of the finishing train, for the first band point and a number of third band points of the band respectively an actual size and a nominal size
• wherein for each band point the respective actual variable for the actual energy content of the respective band point and the respective nominal value for the nominal energy content of the respective band point are characteristic,
• wherein for each band point the respective actual size is related to a location in front of the finishing train and the respective nominal value is related to a location behind the finishing train,
• wherein the third band points run into the finishing train before the first band point.

The object of the present invention is to provide opportunities to be able to reliably determine, in a reliable manner, even before the arrival of a band point in the finishing train, the guide variable not only for this band point, but also for band points entering the finishing line after this band point.

The object is achieved by an operating method for a finishing train with the features of claim 1. Advantageous embodiments of the operating method are the subject of the dependent claims 2 to 14.

• dass einem Steuerrechner für die Fertigstraße spätestens zu einem Zeitpunkt, zu dem ein erster Bandpunkt des Bandes sich noch vor der Fertigstraße befindet, für den ersten Bandpunkt, eine Anzahl von zweiten Bandpunkten und eine Anzahl von dritten Bandpunkten des Bandes jeweils eine Istgröße und eine Sollgröße bekannt sind,
• dass für jeden Bandpunkt die jeweilige Istgröße für den Ist-Energieinhalt des jeweiligen Bandpunktes und die jeweilige Sollgröße für den Soll-Energieinhalt des jeweiligen Bandpunktes charakteristisch sind,
• dass für jeden Bandpunkt die jeweilige Istgröße auf einen Ort vor der Fertigstraße bezogen ist und die jeweilige Sollgröße auf einen Ort hinter der Fertigstraße bezogen ist,
• dass die zweiten Bandpunkte nach dem ersten Bandpunkt und die dritten Bandpunkte vor dem ersten Bandpunkt in die Fertigstraße einlaufen,
• dass der Steuerrechner vor dem Einlaufen des ersten Bandpunktes in die Fertigstraße für den ersten Bandpunkt und zumindest einen Teil der zweiten Bandpunkte anhand einer für den jeweiligen Bandpunkt spezifischen Ermittlungsvorschrift jeweils eine Leitgröße ermittelt,
• dass die jeweilige Leitgröße dafür charakteristisch ist, mit welcher Leitgeschwindigkeit der Steuerrechner die Fertigstraße zum Zeitpunkt des Einlaufens des jeweiligen Bandpunktes in die Fertigstraße betreibt,
• dass der Steuerrechner anhand der für den jeweiligen Bandpunkt ermittelten Leitgröße die jeweilige Leitgeschwindigkeit ermittelt und die Fertigstraße zum Zeitpunkt des Einlaufens des jeweiligen Bandpunktes in die Fertigstraße mit der jeweiligen Leitgeschwindigkeit betreibt und
• dass für die jeweilige Leitgröße in deren Ermittlungsvorschrift die Istgröße und die Sollgröße des zu diesem Zeitpunkt jeweils in die Fertigstraße eintretenden Bandpunktes sowie die Istgröße und die Sollgröße mindestens eines zu diesem Zeitpunkt bereits in die Fertigstraße eingetretenen Bandpunktes eingehen.

According to the invention, it is provided

• that a control computer for the finishing train at the latest at a time at which a first band point of the tape is still in front of the finishing train, for the first band point, a number of second band points and a number of third band points of the band are each an actual size and a nominal size known,
• that for each band point the respective actual variable for the actual energy content of the respective band point and the respective nominal value for the target energy content of the respective band point are characteristic,
• that for each band point the respective actual size is related to a location in front of the finishing train and the respective nominal value is related to a location behind the finishing train,
• that the second band points after the first band point and the third band points before the first band point run into the finishing train,
• that the control computer ascertains a reference variable before the first band point enters the finishing train for the first band point and at least a part of the second band points on the basis of a determination rule specific to the respective band point,
• that the respective guide variable is characteristic of the guiding speed with which the control computer operates the finishing train at the time of entry of the respective strip point into the finishing train,
• the control computer determines the respective guide speed on the basis of the guide variable determined for the respective band point and operates the finishing train at the time of entry of the respective band point into the finishing train at the respective guide speed and
• that the actual size and the nominal size of the band point entering the finishing line at this point in time as well as the actual size and the nominal size of at least one band point that has already entered the finishing line at this point in time are received for the respective reference variable.

• dass der Steuerrechner jede der Leitgrößen anhand einer Vielzahl von Einzelleitgrößen ermittelt,
• dass jede Einzelleitgröße jeweils auf einen der Bandpunkte bezogen ist, dessen Ist- und Sollgröße in die Ermittlung der jeweiligen Leitgröße eingehen,
• dass der Steuerrechner für jeden Bandpunkt dessen Einzelleitgröße derart ermittelt, dass eine jeweilige Erwartungsgröße mit der korrespondierenden Sollgröße übereinstimmt, und
• dass die jeweilige Erwartungsgröße für einen erwarteten Energieinhalt charakteristisch ist, den der jeweilige Bandpunkt an dem Ort hinter der Fertigstraße, auf den die jeweils korrespondierende Sollgröße bezogen ist, annehmen würde, wenn der Steuerrechner die Fertigstraße während des gesamten Durchlaufs des jeweiligen Bandpunktes durch die Fertigstraße mit einer mit der Einzelleitgröße korrespondierenden Leitgeschwindigkeit betreiben würde.

For example, it may be provided

• that the control computer determines each of the guide variables on the basis of a plurality of individual guide sizes,
• each individual item size is related in each case to one of the band points whose actual and nominal size are included in the determination of the respective reference variable,
• that the control computer determines for each band point whose Einzelleitgröße such that a respective expected size matches the corresponding desired size, and
• the respective expectation variable is characteristic for an expected energy content which the respective band point would assume at the location behind the finishing train to which the respective corresponding nominal value is related if the control computer instructs the finishing train through the finishing line during the entire passage of the respective band point would operate at a Leitgeschwindigkeit corresponding to the Einzelleitgröße.

In order to determine the respective guide variable on the basis of the respective multiplicity of individual guide sizes, the control computer can, for example, carry out a weighted or unweighted averaging.

• anhand der Istgrößen, die in die Ermittlung der Leitgröße für den jeweiligen Bandpunkt eingehen, eine effektive Istgröße und anhand der Sollgrößen, die in die Ermittlung der Leitgröße für den jeweiligen Bandpunkt eingehen, eine effektive Sollgröße ermittelt,
• eine Erwartungsgröße ermittelt, die für einen erwarteten Energieinhalt charakteristisch ist, den der jeweilige Bandpunkt an dem Ort hinter der Fertigstraße, auf den die effektive Sollgröße bezogen ist, annehmen würde, wenn der Steuerrechner die Fertigstraße während des gesamten Durchlaufs des jeweiligen Bandpunktes durch die Fertigstraße mit einer mit der Leitgröße für den jeweiligen Bandpunkt korrespondierenden Leitgeschwindigkeit betreiben würde, und
• die Leitgröße derart ermittelt, dass die Erwartungsgröße an dem Ort hinter der Fertigstraße, auf den die effektive Sollgröße bezogen ist, die effektive Sollgröße aufweist.

Alternatively it can be provided that the control computer for each band point, for which he determined its Leitgröße,

• Based on the actual quantities, which are included in the determination of the guide value for the respective band point, an effective actual size and on the basis of the nominal values, which are included in the determination of the guide variable for the respective band point, an effective target value,
• determines an expected quantity characteristic of an expected energy content which the respective band point would assume at the location behind the finishing train to which the effective target value is related, if the control computer reports the finishing line through the finishing line during the entire passage of the respective band point one would operate with the guide variable for the respective band point corresponding conduction velocity, and
• determines the Leitgröße such that the expected size at the location behind the finishing train to which the effective target size is related, the effective target size.

Again, the control computer to determine the effective actual size and the effective target size make a weighted or unweighted averaging.

• dass der Steuerrechner zum Ermitteln der Leitgrößen die Leitgrößen zunächst als vorläufige Werte ansetzt,
• dass der Steuerrechner für den ersten Bandpunkt und zumindest einen Teil der zweiten und dritten Bandpunkte eine jeweilige Erwartungsgröße ermittelt,
• dass jede Erwartungsgröße für einen erwarteten Energieinhalt charakteristisch ist, den der jeweilige Bandpunkt an dem Ort hinter der Fertigstraße, auf den die jeweils korrespondierende Sollgröße bezogen ist, annehmen würde, wenn der Steuerrechner die Fertigstraße während des gesamten Durchlaufs des jeweiligen Bandpunktes durch die Fertigstraße mit Leitgeschwindigkeiten betreiben würde, die mit den angesetzten Leitgrößen korrespondieren, und
• dass der Steuerrechner die angesetzten Leitgrößen variiert, so dass eine Zielfunktion optimiert wird, in die die Beträge der Differenzen der Erwartungsgrößen von den korrespondierenden Sollgrößen eingehen.

Likewise, it may alternatively be provided

• that the control computer initially determines the guide values as provisional values for determining the guide values,
• the control computer determines a respective expectation variable for the first band point and at least part of the second and third band points,
• each expectation quantity is characteristic of an expected energy content which the respective band point would assume at the location behind the finishing train to which the corresponding target size is related, if the control computer sweeps the finishing train through the finishing line at full speeds throughout the respective band point would operate, which correspond to the set parameters, and
• that the control computer varies the set guide values, so that a target function is optimized, in which the amounts of the differences of the expectation quantities of the corresponding target values are received.

In the case of the latter alternative, it is preferably provided that the target function additionally receives a penalty, by means of which changes in the guide speed are punished.

• dass der Steuerrechner vorab ein Datenfeld erstellt, in dem der Steuerrechner für eine Vielzahl von möglichen Leitgeschwindigkeiten und möglichen Istgrößen die sich für die jeweilige mögliche Istgröße bei der jeweiligen möglichen Leitgeschwindigkeit ergebende Erwartungsgröße hinterlegt, und
• dass der Steuerrechner die Leitgrößen für die Bandpunkte unter Verwendung des Datenfeldes ermittelt.

Regardless of which of the three alternatives mentioned above is taken, the operating method according to the invention is still very compute-intensive. To reduce the computational effort is preferably provided

• in that the control computer prepares in advance a data field in which the control computer stores the expected variable resulting for the respective possible actual variable at the respective possible guide speed for a multiplicity of possible guide speeds and possible actual variables, and
• the control computer determines the guide values for the band points using the data field.

• zumindest für einen Teil der Bandpunkte eine jeweilige Erwartungsgröße ermittelt, die für einen erwarteten Energieinhalt charakteristisch ist, der für den jeweiligen Bandpunkt an dem Ort hinter der Fertigstraße, auf den die jeweils korrespondierende Sollgröße bezogen ist, auf Grund der Leitgeschwindigkeiten, mit denen der Steuerrechner die Fertigstraße während des gesamten Durchlaufs des jeweiligen Bandpunkts durch die Fertigstraße betreibt, erwartet wird,
• nach dem Durchlauf des jeweiligen Bandpunktes durch die Fertigstraße eine Messgröße entgegen nimmt, die für einen Ist-Energieinhalt des jeweiligen Bandpunktes an dem Ort hinter der Fertigstraße, auf den die korrespondierende Sollgröße bezogen ist, charakteristisch ist, und
• anhand eines Vergleichs des erwarteten Energieinhalts mit dem Ist-Energieinhalt selbsttätig ein Modell der Fertigstraße (1) adaptiert und
• das Modell der Fertigstraße dadurch adaptiert, dass er bei der Verwendung des Datenfeldes auf die Istgrößen einen Offset addiert, die Leitgeschwindigkeiten mit einem Skalierungsfaktor skaliert und/oder auf sie einen Offset addiert und/oder auf die unter Verwendung des Datenfeldes ermittelten Erwartungsgrößen einen Offset addiert.

The operating method, as described so far, is already working quite well. It can thereby be further improved that the control computer

• determines at least for a part of the band points a respective expectation variable, which is characteristic of an expected energy content, for the respective band point at the place behind the finishing train, to which the respective corresponding target size is related, due to the conduction velocities, with which the control computer the Mill is operated through the finishing train during the entire run of the respective strip
• after the passage of the respective band point through the finishing train receives a measured variable, which for an actual energy content of the respective band point at the place is characteristic behind the finishing train, to which the corresponding nominal value is related, and
• automatically adapted a model of the finishing train (1) on the basis of a comparison of the expected energy content with the actual energy content and
• adapted the model of the finishing train by adding an offset to the actual values when using the data field, scaling the guide speeds with a scaling factor and / or adding an offset thereto and / or adding an offset to the expected quantities determined using the data field.

In a preferred embodiment of the present invention, the actual size and the desired size of the points already entered the finishing line are received for each master in their determination only if these tape points at the time for which the respective guide is determined, not from the finishing train have leaked. In particular, the actual and nominal values of all band points, which are located at the time when the determined band point enters the finishing train in the finishing train, can be included in the determination of the reference variable for a specific band point.

• eine jeweilige Erwartungsgröße ermittelt, die für einen erwarteten Energieinhalt charakteristisch ist, der für den jeweiligen Bandpunkt an dem Ort hinter der Fertigstraße, auf den die jeweils korrespondierende Sollgröße bezogen ist, auf Grund der Leitgeschwindigkeiten, mit denen der Steuerrechner die Fertigstraße während des gesamten Durchlaufs des jeweiligen Bandpunkts durch die Fertigstraße betreibt, erwartet wird,
• nach dem Durchlauf des jeweiligen Bandpunktes durch die Fertigstraße eine Messgröße entgegen nimmt, die für einen Ist-Energieinhalt des jeweiligen Bandpunktes an dem Ort hinter der Fertigstraße, auf den die korrespondierende Sollgröße bezogen ist, charakteristisch ist, und
• anhand eines Vergleichs des erwarteten Energieinhalts mit dem Ist-Energieinhalt selbsttätig zumindest einen Teil der bereits ermittelten Leitgrößen nachführt.

The operating method, as described so far, is already working quite well. It can thereby be further improved that the control computer at least for a part of the band points

• determining a respective expectation variable characteristic of an expected energy content corresponding to the respective band point at the location behind the finishing train to which the respective corresponding target quantity is related, based on the conduction velocities with which the control computer controls the finishing train during the entire run of the each band point through the finishing train is expected,
• after the passage of the respective band point through the finishing train receives a measured variable, which for an actual energy content of the respective band point at the place is characteristic behind the finishing train, to which the corresponding nominal value is related, and
• based on a comparison of the expected energy content with the actual energy content automatically tracks at least a portion of the already determined guide variables.

When the control computer compares the expected energy content with the actual energy content and tracks the control values, it is possible for the computer to perform the comparison for all band points one after the other. However, it is sufficient to perform the comparison for a part of the band points, for example every third or every tenth band point.

Of course, when the control computer tracks the guiding variables, the control computer takes into account the changed course of the characteristic variable when determining expectation variables.

It is possible that the control computer carries out the tracking for all already determined control variables. Preferably, however, it is provided that, based on the comparison, the control computer automatically tracks only those reference variables which were determined for band points which have a minimum distance at the time of tracking from the entrance of the finishing train. This procedure is particularly advantageous if the control computer or another control device uses the determined control variables to determine at least one further control variable and the further control variable is delayed by a dead time and acts only locally on the belt. This procedure is optimal if the minimum distance is determined in such a way that a time difference corresponding to the minimum distance is at least as long as the dead time.

In addition to tracking already determined control variables, the control computer can - of course - adapt the determination rule for as yet unidentified control variables as such. Depending on the situation of the individual case, the adaptation result can already be used to determine further parameters of the same Band or only when determining reference values for subsequent bands.

The two last-mentioned procedures - keyword "tracking already determined parameters" on the one hand and "adapting the determination rule" on the other hand, for example, be coupled to each other such that the control computer includes a model of the finishing train, is determined by means of which temperature for a band point on the outlet side of the finishing train is expected when the respective band point upstream of the finishing train has a given temperature and passes through the finishing train while the finishing train is operated at a given guide speed. In this case, the model can be adapted immediately. This corresponds to the adaptation of the investigation rule. Then, for at least one of the guide variables already determined, the guide variable is newly determined using the adapted model of the finishing train. In terms of approach, this corresponds to tracking the already determined parameters. Optionally, a smooth transition from the originally determined control variables to the newly determined control parameters can take place.

The operating method according to the invention already represents a considerable advance over the prior art even if the prediction horizon is relatively small, for example three to five band points. Its full superiority shows the operating method according to the invention, however, in particular when the first band point and the part of the second band points, for which their respective Leitgröße was determined before the arrival of the first band point in the finishing train, a prediction horizon corresponding to at least as large as the dead time is, with the other manipulated variable acts on the tape. This applies in particular in cooperation with the tracking of the already determined control variables, if the tracking is also tuned to the said dead time.

In a preferred embodiment of the present invention, it is further provided that the control computer chains together the determined guiding variables or the corresponding guiding speeds by a spline, so that a guiding-speed course resulting from the linking is continuous and differentiable. The resulting advantage is a smoother and more uniform operation of the finishing train. This is especially true if the resulting guide variable course is not only differentiable, but is constantly differentiable.

The control computer preferably executes the determination of the control variables online or in real time as part of a precalculation.

The object of the invention is further achieved by a computer program of the type mentioned. The computer program is designed in this case such that the control computer executes an operating method with all steps of an operating method according to the invention.

The object is further achieved by a control computer for a finishing train for rolling a belt, which is designed such that it carries out such an operating method during operation.

The object is further achieved by a finishing train for rolling a belt, which is equipped with such a control computer.

FIG 1

schematisch eine Warmbandstraße,

FIG 2

ein Ablaufdiagramm,

FIG 3 bis 6

beispielhaft verschiedene Zustände einer Fertigstraße,

FIG 7

beispielhaft eine Momentaufnahme der Fertigstraße,

FIG 8 bis 11

Ablaufdiagramme,

FIG 12

ein Modell der Fertigstraße,

FIG 13

ein Ablaufdiagramm,

FIG 14

ein Zeitdiagramm und

FIG 15

ein Ablaufdiagramm.

Further advantages and details will become apparent from the following description of exemplary embodiments in conjunction with the drawings. In a schematic representation:

FIG. 1

schematically a hot strip mill,

FIG. 2

a flow chart,

FIGS. 3 to 6

exemplary different states of a finishing train,

FIG. 7

an example of a snapshot of the finishing train,

FIGS. 8 to 11

Flowcharts,

FIG. 12

a model of the finishing train,

FIG. 13

a flow chart,

FIG. 14

a time chart and

FIG. 15

a flowchart.

According to FIG. 1 a hot strip mill comprises at least one finishing train 1. In the finishing train 1, a band 2 is to be rolled. The band 2 is usually a metal band, for example a steel band. Alternatively (to steel), the band may be made of copper, brass, aluminum or another metal.

The finishing train 1 has to roll the belt 2 a rolling mill 3 or - as in FIG. 1 shown - several rolling stands 3 on. Shown in FIG. 1 three such stands 3. The actual number of rolling stands 3 can be three, as shown. Alternatively, it may be different from three, in particular larger. As a rule, the number of rolling stands 3 is four to eight, in particular 5 to 7. Furthermore, of the rolling stands 3 in FIG. 1 only the work rolls shown (2-high). In general, the rolling stands 3 include in addition to the work rolls back-up rolls (4-high), sometimes additionally also intermediate rolls (6-high).

The finishing train 1 may comprise a heating device 4, for example an induction furnace. If the heating device 4 is present, it is usually located at the entrance of the finishing train 1. Alternatively or additionally - as with intermediate stand cooling devices - 3 heaters may be present between the rolling stands. The heater 4, if present, is considered within the scope of the present invention as part of the finishing train 1. As an alternative or in addition to the heating device 4, the finishing train 1 may have interstitial cooling devices 5. If the inter-frame cooling devices 5 present are each inter-frame cooling device 5 of two of the rolling stands 3 eingabelt. If they are present, they are part of the finishing train 1. Each intermediate stand cooling device 5 has at least one control valve 5 'and at least one spray nozzle 5 ".

The finishing train 1 may further be downstream of a cooling section 6. If the cooling section 6 is present, it has cooling devices 7. Each cooling device 7 has at least one control valve 7 'and at least one spray nozzle 7 ".

Both by means of the intermediate stand cooling devices 5 and by means of the cooling devices 7, the strip 2 is cooled with a liquid cooling medium (usually water with or without admixtures). The difference between the intermediate stand cooling devices 5 and the cooling devices 7 of the finishing train 6 is that the cooling devices 7 are arranged behind the last rolling stand 3 of the finishing train 1, the intermediate stand cooling devices 5 between each two of the rolling stands 3.

According to FIG. 1 the finishing train 1 is further equipped with a control computer 8. The control computer 8 is used at least to control the finishing train 1, so the rolling stands 3 and - if present - the heater 4 and the interstand cooling devices 5. Optionally, the control computer 8 also control other facilities, such as the cooling section 6 and their cooling devices 7. Alternatively, the Cooling section 6 are controlled by another controller 8 '.

The mode of operation of the control computer 8 is determined by a computer program 9 which is supplied to the control computer 8, for example via a mobile data carrier 10. The mobile data carrier 10 can be configured as required, for example as a CD-ROM, as a USB memory stick or as an SD memory card. On the disk 10 is the computer program 9 stored in machine-readable form, for example in electronic form.

The computer program 9 comprises machine code 11 with which the control computer 8 is programmed and which can be processed directly by the control computer 8. The processing of the machine code 11 by the control computer 8 causes the control computer 8 to operate the finishing train 1 in accordance with an operating method which will be explained in more detail below. Programming with the computer program 9 thus effects a corresponding configuration of the control computer 8.

In the context of the operating procedure, the control computer 8 must comply with FIG. 2 in a step S1 for a first band point 12 of the band 2, a number of second band points 13 of the band 2 and a number of third band points 13 'of the band 2 each an actual size G and a target size G * be known, and at the latest to one Time at which the first band point 12 is still in front of the finishing train 1.

It will be apparent from the explanations below that the actual value G and the setpoint G * for the first band point 12, the second band points 13 and the third band points 13 'need not all be known to the control computer 8 at the same time. However, it will also be apparent that the knowledge must be completed before the first band point 12 enters the finishing train 1.

The second band points 13 are all behind the first band point 12, so they run after the first band point 12 in the finishing train 1 a. The third band points 13 'enter the finishing train 1 before the first band point 12. The FIGS. 3 to 6 show corresponding embodiments.

The actual size G of each band point 12, 13, 13 'is characteristic of the energy content which the respective band point 12, 13, 13' has at a location xE in front of the finishing train 1. The actual size G is thus at the location xE in front of the finishing train 1 based. The location xE can be determined as needed. In particular, it may be according to FIG. 1 to act at a location immediately before the first device 4, 3 of the finishing train 1, by means of which - directly or indirectly - the temperature of the belt 2 is affected. It is still possible that a temperature measuring device is arranged at this location. In general, however, the temperature measuring device 14 is arranged upstream of the location Xe.

The desired value G * of each band point 12, 13, 13 'is characteristic of the energy content which the respective band point 12, 13, 13' should have at a location xA behind the finishing train 1. The desired values G * are therefore related to the location xA behind the finishing train 1. The location xA can be determined as required, analogously to the location xE in front of the finishing train 1. For example, it may be the location of a temperature measuring device 15 downstream of the finishing train 1, but upstream of the cooling section 6.

The type of the actual size G and the target size G * can be determined as needed. As a rule, these are the corresponding temperatures. Alternatively, an enthalpy in particular comes into question.

For the sake of good order, it should be mentioned that the term "location" below always refers to a location which is stationary with respect to the finishing train 1. The term band point ", in contrast, always refers to a point which is stationary relative to the band 2. Distances between the band points 12, 13, 13 'from one another are not determined by their geometric distances in the context of the present invention, since these distances are determined by change the rolling of the belt 2 in the finishing train 1. The distances are defined rather by the mass which is located between the belt points 12, 13, 13 '.

The band points 12, 13, 13 'may, based on the mass of the band 2 located between them, be equidistant. alternative the band points 12, 13, 13 'can be defined by the fact that - for example by means of the temperature measuring device 14 - in each case a measured value for the actual quantity G is detected in equidistant time steps. The time interval between two successive band points 12, 13, 13 'is generally between 100 ms and 500 ms, typically between 150 ms and 300 ms. For example, it may be 200 ms.

In a step S2, the control computer 8 determines - of course, before the arrival of the first band point 12 in the finishing train - for the first band point 12 on the basis of a determination rule a Leitgröße L *. In a step S3, the control computer 8 determines at least for a part of the second band points 13 also on the basis of a determination rule a respective control variable L *. The control computer 8 also executes step S3 before entering the first strip point 12 into the finishing train 1.

Steps S2 and S3 of FIG. 2 usually form a unit in practice. The separate illustration in FIG. 2 is merely a better illustration of the present invention.

Preferably, the control computer 8 determines in the context of step S3 for all second band points 13, which - starting from the first band point 12 - are within a predetermined prediction horizon H, whose master size L *. If, therefore, in the context of step S3 for a particular second band point 13, its reference variable L * is determined, as a rule, for all other second band points 13 which lie between the first band point 12 and the specific second band point 13, their respective reference variable L * determined.

The determined guiding variables L * are respectively characteristic of the guiding speed vL of which the control computer 8 operates the finishing train 1 when the belt point 12, 13, for which the respective guiding variable L * was determined, enters the finishing train 1. The guide speed vL can be, for example be the speed at which the tape 2 enters the finishing train 1. Alternatively, it may be the speed with which the belt 2 leaves the finishing train 1. Other sizes - for example, a determination of the mass flow or a roller speed or a roller peripheral speed - are conceivable. It is crucial that all of the strip and roll peripheral speeds occurring in the finishing train 1 are uniquely determined by the guide speed vL, possibly in conjunction with stitch acceptments and debit trains.

In a step S4, the control computer 8 determines, if necessary, the corresponding guide speeds vL on the basis of the control variables L *. In a step S5, the control computer 8 operates the finishing train 1 in accordance with the guide speeds vL determined in step S4. The control computer 8 thus always sets the guide speed vL in such a way that the finishing line 1 is currently operated at the guide speed vL, which corresponds to the guide variable L * of the strip point 12, 13 currently entering the finishing line 1.

The determination rule for determining the guiding variables L * is in each case specific to the respective band point 12, 13. The determined value of the reference variable L * for a particular band point 12, 13 can not therefore be readily determined by the value of the reference variable L * for another band point 12, 13 are closed. In particular, the actual size G and the desired size G * of the corresponding band point 12, 13 enter into the determination rule for the reference variable L * for a specific band point 12, 13. In addition, the actual quantities G and the set values G * of at least one further band point 12, 13, 13 ', which at the time at which the considered band point 12, 13 enters the finishing train 1, already enter the finishing train 1 in the respective determination rule occurred. This issue will be discussed below in connection with FIG. 7 clearly explained.

FIG. 7 shows an example of a snapshot of the finishing train 1, while the band 2 is rolled in the finishing train 1. The band points 12, 13 are used in conjunction with the explanations to FIG. 7 as band points Pi (i = 1, 2, 3, ...).

Suppose, according to the representation of FIG. 7 are currently the band points P5 to P30 in the finishing train 1. The band points P1 to P4 have already left the finishing train 1 in this case, so have exited the finishing train 1 again. The band points P31 to P35 are still in front of the finishing train 1. The band point P31 occurs in this case next in the finishing train 1 a. After the band point P31, the band points P32, P33, P34 and P35 enter the finishing train 1 in succession. The actual and target variables G, G * are known up to and including the band point P35.

• die Istgröße G und die Sollgröße G* für den Bandpunkt P4 und
• die Istgröße und die Sollgröße G, G* für mindestens einen der Bandpunkte P1, P2 und P3.

At the in FIG. 7 the determination of the control variable L * for the belt point P4 must already be completed for a long time, since the belt point P4 not only already entered the finishing train 1, but has even already exited the finishing train 1 again. In the determination of the guide size L *, with which the finishing train 1 was operated at the time when the band point P4 has entered the finishing train 1, received according to the invention

• the actual size G and the target size G * for the band point P4 and
• the actual size and the target size G, G * for at least one of the band points P1, P2 and P3.

Assuming that the prediction horizon H corresponds to four band points, the determination of the guide quantity L * for the band point P4 must have been completed one time clock before the point in time when the band point P1 entered the finishing train 1.

• die Ist- und die Sollgröße G, G* für den Bandpunkt P7 und
• die Ist- und die Sollgröße G, G* für mindestens einen der Bandpunkte P1 bis P6.

Analogously, the determination of the reference variable L * for the band point P7 is discussed

• the actual and the desired size G, G * for the band point P7 and
• the actual and the desired size G, G * for at least one of the band points P1 to P6.

This determination must have been completed at the latest at the time of the occurrence of the band point P3.

• die Ist- und die Sollgröße G, G* für den Bandpunkt P30 und
• die Ist- und die Sollgröße G, G* für mindestens einen der Bandpunkte P1 bis P29.

The band point P30 is the band point that has just entered the finishing train 1. In the determination of the guide L *, which must have been completed by the time of the occurrence of the band point P26, have been received

• the actual and the target size G, G * for the band point P30 and
• the actual and the desired size G, G * for at least one of the band points P1 to P29.

As a rule, it is sufficient for the determination of the guiding quantity L * for the band point P30 to take into account the actual and nominal quantities G, G * of the band points P5 to P30, ie those band points which, according to the illustration of FIG FIG. 7 currently located in the finishing mill 1.

In an analogous manner, the guiding variables L * are determined for the band points P31 to P35. The band point P31 corresponds in the representation of FIG. 7 the determination of the guide quantities L * for these band points P31 to P35 must be completed at the latest at the time of the occurrence of the band point P27 to P31 in the finishing train 1 at the latest. The band points P1 to P30 correspond to the third band points 13 '.

• die Ist- und die Sollgröße G, G* für den Bandpunkt P31 und
• die Ist- und Sollgrößen G, G* für mindestens einen der Bandpunkte P1 bis P30, vorzugsweise für mindestens einen der Bandpunkte P6 bis P30.

In the determination of the guide L * for the band point P31 go

• the actual and the desired size G, G * for the band point P31 and
• the actual and desired values G, G * for at least one of the band points P1 to P30, preferably for at least one of the band points P6 to P30.

The latter applies in particular because the band points P1 to P5 have already exited the finishing train 1 again at the point in time at which the band point P31 enters the finishing train 1.

• die Ist- und die Sollgröße G, G* für den Bandpunkt P35 und
• die Ist- und Sollgrößen G, G* für mindestens einen der Bandpunkte P1 bis P34.

In an analogous manner, the guiding variables L * for the band points P32 to P35 can also be determined. For example, for the band point P35 go into the determination for the guide size L *

• the actual and the desired size G, G * for the band point P35 and
• the actual and desired quantities G, G * for at least one of the band points P1 to P34.

The actual and target variables G, G * for the band points P1 to P9 can hereby be disregarded since the band points P1 to P9 have already exited the finishing train 1 again at the point in time when the band point P35 enters the finishing train 1.

For the other band points P32, P33 and P34 analogue versions apply.

In a preferred embodiment of the present invention is for each entering the finishing train 1 band point 12, 13 - for example, for the band point P31 according to FIG. 7 - The Leitgröße L * thus determined on the basis of the actual and target values G, G * those band points 12, 13, 13 ', which are currently in the finishing mill 1 at this time, so have not yet leaked from the finishing train 1.

In the finishing train 1 are usually at the same time a plurality of band points 12, 13, 13 '. Typical numerical values lie between 10 and 200, for example between 50 and 100. It is possible to take into account only a few band points 12, 13, 13 'of the band points 12, 13, 13' which are currently in the finishing train 1 at a particular time, for example, every second or every fourth band point 12, 13, 13 '. This approach leads to a reduced computational effort and still delivers acceptable results. Preferably, however, the actual and nominal values G, G * of all band points 12, 13, 13 'are taken into account for the determination of the reference variable L * for a specific band point 12, 13, which at the time of entry of that band point 12, 13, whose control variable L * is determined to be in the finishing train 1 already in the finishing mill 1.

In the FIG. 7 The illustration shown is of course purely exemplary. For example, the number of (third) band points 13 'located in the finishing train 1 is purely exemplary. Also, the number of (second) band points 13 whose lead variable L * is predicted (here the band points P32 to P35) is purely exemplary. Also, the prediction horizon H is purely exemplary. In particular, in practical applications, the prediction horizon H can be several seconds, ie at a time cycle of, for example, 200 ms per measured value acquisition of the actual quantity G a correspondingly five times the number of band points 12, 13. In some cases even a prediction horizon H of up to one minute and more is possible. which corresponds to a prediction horizon H of 300 band points and more at a time interval of 200 ms from band to band point.

It is possible that the control computer 8 in step S1 of FIG. 2 the actual and nominal values G, G * are known for all band points 12, 13, 13 'of the (entire) band 2. In this case, it is possible that the control computer 8 passes through the steps S2 and S3 only once and in steps S2 and S3 - so to speak in one stroke - determines the guiding variables L * for all band points 12, 13, 13 'of the band 2. In this case the control computer 8 executes the determination of the control variables L * on the basis of a prediction online.

Alternatively, it is possible that the control computer 8 in the context of step S1 of FIG. 2 the actual and nominal quantities G, G * are known for all band points 12, 13, 13 'of the entire band 2, he in steps S2 and S3 of FIG. 2 but always determined only for some of the band points 12, 13, 13 'whose guiding variables L *. In this case, steps S2 and S3 are as in FIG. 2 indicated by dashed lines, incorporated in a loop. In this case, the control computer 8 executes the determination of the control variables L * in real time with the control of the finishing train 1. In this case, the control computer 8 determines the guiding variables L * by the prediction horizon H, so to speak.

As in FIG. 2 is also indicated by dashed lines, it is even possible that the step S1 is included in the loop with. Also in this case, the control computer 8 executes the determination of the control variables L * in real time.

In the event that the step S1 is also involved in the loop, the control computer 8 will only know the actual and nominal values G, G * of band points 12, 13 during a certain passage of the loop, which are not yet in the finishing train 1 occurred. The actual and target variables G, G * of the band points 13 ', which have already entered the finishing train 1, are known to the control computer 8 in this case, however, on the basis of earlier loop passes. In this case, it is only necessary for the control computer 8 to "remember" the "old" actual and target variables G, G *.

For determining the guiding variables L * for a specific band point 12, 13 - ie for implementing steps S2 and S3 of FIG FIG. 2 - Different approaches are possible. The different alternatives are listed below in succession Connection with the FIG. 8 . 9 and 10 explained in more detail. As needed is here FIG. 7 to bring with.

In a first possible embodiment of the steps S2 and S3 of FIG. 2 the control computer 8 selects according to FIG. 8 in a step S11 first one of the band points 12, 13, whose actual and desired size G, G * the control computer 8 are already known. For example, the control computer 8 selects the band point P31 of FIG FIG. 7 ,

In a step S12, the control computer 8 determines all band points 12, 13, 13 ', whose actual and desired values G, G * are included in the determination of the control variable L * for the band point 12, 13, which the control computer 8 has selected in step S11 , For example, the control computer 8 - see FIG. 7 - Determine the band points P6 to P31 for the band point P31. In an analogous manner, the control computer would determine the band points P7 to P32 for the band point P32 in step S12, for the band point P33 the band points P8 to P33, etc.

In a step S13, the control computer 8 selects one of the band points 12, 13, 13 'determined in step S12. In a step S14, the control computer 8 determines a single-wire size 1 * for the tape point 12, 13, 13 'selected in step S13-for example for the tape point P6. Only the actual size G and the target size G * of the band point 12, 13, 13 'selected in step S13 are included in the determination of the individual wire size 1 *. The respective Einzelleitgröße 1 * is therefore related to this one band point 12, 13, 13 '.

The Einzelleitgröße 1 * determines a corresponding conduction velocity vL. The control computer 8 assumes that the considered in step S14 band point 12, 13, 13 'passes through the finishing train 1 and the finishing train 1 during the entire passage of the considered band point 12, 13, 13' through the finishing line 1 - ie from the time of Entering the finishing train 1 until it leaves the finishing train 1 - is constantly operated at this guide speed vL, which is determined by the corresponding individual wire size 1 *. In this case, an energy content is expected for the considered band point 12, 13, 13 'at the location xA, to which the nominal value G * of the considered band point 12, 13, 13' is related. The control computer 8 determines this expected energy content. The determination of the expected energy content can be determined by the control computer 8, for example by means of a finishing road model. Suitable finishing models are known as such. They are used, for example, to determine the expected final rolling temperature, see the already mentioned DE 103 21 791 A1 ,

The expected energy content is characterized by a corresponding expected quantity GE. The expectation variable GE can alternatively be the temperature or the enthalpy, analogous to the actual and set values G, G *. The control computer 8 determines the Einzelleitgröße 1 * for the considered band point 12, 13, 13 'in step S14 such that the expected size GE with the target size G * for the considered band point 12, 13, 13' matches.

In a step S15, the control computer 8 checks whether it has already performed step S14 for all band points 12, 13, 13 'to be used. If this is not the case, the control computer 8 returns to step S13. In the renewed execution of step S13 of course, the control computer 8 selects another, previously not considered band point 12, 13, 13 ', which enters into the determination of the sought Leitgröße L *, for example, the band point P7.

If the control computer 8 determines in step S15 that it has already determined all the required individual line sizes 1 *, the control computer 8 proceeds to a step S16. In step S16, the control computer 8 determines the reference variable L * for all single-element sizes 1 *, which it has determined during the repeated execution of step S14 For example, the control computer 8 may form the weighted or unweighted mean value of the individual line sizes 1 *.

In a step S17, the control computer 8 checks whether it has already carried out the steps S11 to S16 for all band points 12, 13 whose guide variables L * are to be calculated. If this is not the case, the control computer 8 returns to step S11. Of course, the control computer 8 selects another band point 12, 13 which has not yet been considered. Otherwise, the method of FIG FIG. 8 completed.

The procedure of FIG. 8 is implemented slightly differently in practice than explained above. For the Einzelleitgröße 1 * for a certain band point 12, 13, 13 '- for example, for the band point P28 of FIG. 7 - goes into the determination of the leading variable L * many band points 12, 13, 13 ', for example - based on FIG. 7 - in the determination of the band points P28, P29, ... P53. Of course, it is possible and even preferred to determine the respective Einzelleitgröße 1 * only once and then save, so that they must be retrieved for later uses only from the memory.

Alternatively to the procedure of FIG. 8 is it according to FIG. 9 possible, the steps S13 to S16 of FIG. 8 according to FIG. 9 by steps S21 to S23. Steps S11, S12 and S17 of FIG FIG. 8 be in the course of FIG. 9 out FIG. 8 accepted.

In step S21, the control computer 8 uses the actual variables G of the band points 12, 13, 13 'determined in step S12 to determine an effective actual variable G'. In an analogous manner, the control computer 8 determines an effective setpoint G '* in step S22 on the basis of the setpoint values G * of the band points 12, 13, 13' determined in step S12. For example, the control computer 8 in steps S21 and S22 a weighted or unweighted Averaging. Regardless of which approach is taken, however, the procedures of steps S21 and S22 should correspond.

In step S23, the control computer 8 determines the reference variable L * for the band point 12, 13 selected in step S11.

The master variable L * determined in step S23 corresponds to a corresponding master speed vL. If the selected in step S11 band point 12, 13 at the location xE, to which the actual size G of the selected in step S11 band point 12, 13, the effective actual size G 'would have and the control computer 8, the finishing line 1 during the entire run of the band point 12, 13 selected in step S11 would operate at this guide speed vL, an actual energy content would be expected for this band point 12, 13 at the location xA, to which the setpoint G * of the band point 12, 13 selected in step S11 is related which is characterized by an expected quantity GE. The control computer 8 determines the control variable L * in step S23 such that the determined expectation variable GE agrees with the effective setpoint G '*. The determination of the expected variable GE can - analogous to the procedure of step S14 of FIG. 8 - By means of a corresponding, known per se finishing road model.

• Gemäß FIG 10 setzt der Steuerrechner 8 in einem Schritt S31 die Leitgrößen L*, die er ermitteln soll, - also die Leitgrößen L* für den ersten Bandpunkt 12 und für zumindest einen Teil der zweiten Bandpunkte 13 - zunächst als vorläufige Werte an.

Alternatively to the procedures of the FIG. 8 and 9 it is possible that the guiding variables L * according to FIG. 10 be determined as follows:

• According to FIG. 10 the control computer 8 sets in a step S31 the guiding variables L *, which it is to determine, ie the guiding quantities L * for the first band point 12 and for at least a part of the second band points 13, first as provisional values.

In a step S32, the control computer 8 determines a respective expectation variable GE for the band points 12, 13 considered in step S31. The expected values GE determined in step S32 are in each case characteristic of the expected energy content of the respective band point 12, 13 which is expected for the respective band point 12, 13, if the respective band point 12, 13 is the finishing line 1 in accordance with the scheduled course of the guide speed vL - As defined by the sequence of the guiding variables L * - goes through. The expected energy contents GE are each related to the location xA, to which the desired quantities G * for the band points 12, 13 are related.

In a step S33, the control computer 8 forms an objective function Z. At least the amounts of the differences of the expectation variables GE from the corresponding desired variables G * enter into the objective function Z. For example, the objective function Z may include a sum, corresponding to the representation in FIG FIG. 10 For example, each summand is the square of the difference of an expected quantity GE from the corresponding target size G *.

It is possible to use the above-described objective function Z as described so far. Preferably, however, further variables enter the objective function Z. In particular, in the target function Z additionally enter a Strafterm, by means of which changes in the conduction velocity vL are punished. For example, the objective function Z can thus have the following form: $$Z={\displaystyle \underset{i}{\Sigma }}{\alpha }_i{\left({\mathit{GE}}_i-G{*}_i\right)}^2+{\displaystyle \underset{j}{\Sigma }}{\beta }_i{\left({\mathit{vL}}_j-{\mathit{vL}}_{j-1}\right)}^2$$

In the two sums, different indices i, j were used because the indices i and j run over different areas. α _i and β _j are - in principle arbitrary, non-negative - weighting factors.

In a step S34, the control computer 8 varies the applied guiding variables L * with the aim of optimizing the target function Z according to the embodiment above. With a correspondingly different design of the objective function Z, maximizing would also be possible.

The procedures of the FIG. 8 and 9 are applicable regardless of whether in a single execution of steps S2 and S3 of FIG. 2 only a few guiding variables L * are determined or whether the guiding variables L * for all band points 12, 13, 13 'of the band 2 are determined in advance. The procedure of FIG. 10 on the other hand, meaningful results are usually only obtained if the prediction horizon H covers the entire band 2 or, if the band 2 is long enough, is sufficiently large. In particular, in the approach of FIG. 10 in the case of a long band 2 of the prediction horizon H be so large that it is at least equal to the effective finishing road length, better at least twice as large. The effective finishing line length is determined by the maximum number of tape points 12, 13, 13 'simultaneously located in the finishing train 1.

Both in the context of the approach of FIG. 8 as well as within the framework of FIG. 9 as well as within the framework of FIG. 10 expectation quantities GE must be determined. The determination of the expected quantities GE takes place - from the point of view - by means of a model of the finishing train 1, which models the thermal processes (heat conduction and heat transfer, possibly also phase transformations and microstructure) in the finishing train 1. Such models are known per se, see the DE 103 21 791 A1 ,

It is possible to use such a model as such also in steps S14, S23 and S32. However, it is preferred that the control computer 8 according to the representation of FIG. 11 in a step S41 in advance - that is, before the determination of the control variables L * - created a data field. The control computer 8 deposits in the data field in a step S42 for a multiplicity of possible guide speeds vL and possible actual variables G, which expectation variable GE results for the respective possible actual variable G and the respective possible guide speed vL. Because in this case, the control computer 8 in the context of the appropriately configured steps S2 and S3 of FIG. 2 (or the steps S14, S23 and S32) determine the guiding variables L * for the band points 12, 13 using the data field. In the procedure according to FIG. 8 the control computer 8 determines the Einzelleitgrößen l * using the data field, so that the use of the data field is indirect nature. In the procedure according to FIG. 9 the respective control variable L * is determined directly. In the procedure according to FIG. 10 the data field is used to determine the respectively resulting expected quantities GE.

By using the data field, a considerable acceleration can be achieved. For even the data field must indeed be determined within the framework of a preliminary calculation, that is, when the hot strip 2 for rolling in the finishing train 1 is already ready. The data field can not be determined offline. Rather, the data field must be determined online, ie after the tape data have been given to the control computer 8. Therefore, only a few seconds are available for the determination of the data field. Nevertheless, a significant acceleration occurs. For in the context of the data field, only relatively few values have to be completely calculated by means of the model of the finishing train 1, for example for every 10 possible actual variables G and 10 possible guiding speeds vL, so that the model calculation has to be carried out for a total of 100 values. However, this is still significantly faster than later in the context of steps S14, S23, S32 for each individual band point 12, 13, 13 'by means of the model of the finishing train 1 whose expected size GE to determine.

The nature of the integration of the data field in the procedures of FIG. 8 and 9 is immediately apparent, since the actual size G the Control computer 8 is known and the relationship between the possible conduction velocity vL and the expectation variable GE is unambiguous (the larger the given actual size G is the conduction velocity vL, the greater the expected energy content of the corresponding band point 12, 13, 13 '). The data field is also in connection with the approach of FIG. 10 applicable. For it is possible to form in the first and, as a rule, already very good approximation for a specific band point 12, 13, 13 'the mean value of all guiding variables G * or of all guiding speeds vL with which the finishing train 1 during the passage of the relevant band point 12, 13, 13 'is operated by the finishing train 1. This mean value can be regarded as the effective guide speed vL. The data field can thus be evaluated at this point in order to determine the expectation variable GE for the corresponding band point 12, 13, 13 '.

The data field can be designed as needed. For example, it can be a pure interpolation field with, for example, 5, 8, 10, ... interpolation points per dimension. In this case, it is possible to interpolate between individual support points linearly or nonlinearly (for example by means of splines). Alternatively, the data field may be formed, for example, as a neural network.

If the actual size G is based on a measured quantity, for example detected by the temperature measuring device 14, it is possible to process the measured variables directly. As a rule, the location xE is located in front of the finishing train 1, to which the actual quantities G are related, but behind the temperature measuring device 14. It is therefore necessary to convert the measured quantities into the actual quantities G (which refer to the location xE). This is relatively easy, since only an air gap must be calculated. Input values for the air gap are the temperature value measured by means of the temperature measuring device 14 and the time which accumulates for the respective band point 12, 13, 13 'until the corresponding band point 12, 13, 13' projects the location xE reached the finishing train 1. The time is given for each band point 12, 13, 13 'by the conduction velocities of the upstream band points 12, 13, 13'.

This creates a feedback problem. To solve this problem, a preliminary course of the guide speed vL is initially set. Assuming that this set course applies, the actual quantities G are determined, which are related to the location xE before the finishing train 1. With the now determined actual variables G, the course of the guide speed vL is determined. The determined course of the guide speed vL is again used to determine the actual variables G new. In practice it turns out that the approach converges very fast. As a rule, only a few iterations are required - for example, three to five iterations - in order to achieve sufficiently stable results.

In the context of the previous explanations of the present invention, it has been assumed that the finishing train 1 has neither an input-side heating device 4 nor inter-frame cooling devices 5. If the heating device 4 and / or the inter-frame cooling devices 5 are present, the operating method according to the invention can be adapted accordingly. The necessary adjustments will be explained below in connection with a single inter-frame cooling device 5. However, the corresponding embodiments are readily applicable to embodiments of the finishing train 1, which has more than one inter-frame cooling device 5 and / or an input-side heater 4, the heater 4 may be provided alternatively or in addition to the inter-frame cooling devices 5.

It is therefore assumed that the finishing train 1 has a single intermediate-frame cooling device 5, for example between the second and the third rolling stand 3 as shown in FIG FIG. 1 , In this case, the model of the finishing mill 1 - this is immediately and without further ado - divided into three submodels, which in FIG. 12 are referred to as partial model TM1, partial model TM2 and partial model TM3.

The partial model TM1 is similar in design to a model of a finishing train 1, as previously assumed, ie a model of a finishing train 1 without interstand cooling devices. It models the behavior of the belt 2 in the finishing train 1 to ahead of the inter-frame cooling device 5. The partial model TM1 receives as input variables the actual size G of a band point 12, 13, 13 'and the leading speed vL and the corresponding Leitgeschwindigkeitsverlauf. The submodel TM1 supplies as output variable an expectation variable TE which corresponds to an expected energy content with which the corresponding band point 12, 13, 13 'enters the inter-frame cooling device 5. The partial model TM1 is two-dimensional, because it has two input variables, namely the actual size G and the guide speed vL.

The partial model TM2 models the inter-frame cooling device 5 as such. It receives as input quantities the expected quantity TE delivered by the partial model TM1, the guide speed vL, with which the respective strip point 12, 13, 13 'passes through the intermediate stand cooling device 5 and a coolant quantity M, given as such, with which the strip 2 is acted upon per unit of time , The amount M of cooling fluid per unit time is preferably defined as a function of the amount of material of the belt 2, which has already passed the inter-frame cooling device 5. Alternatively, the amount M of cooling fluid per unit of time may be defined, for example, as a function of the respective band point 12, 13, 13 ', which is just entering the inter-frame cooling device 5.

The partial model TM2 thus has three input variables, in contrast to a model of a finishing train 1 without interstand cooling devices. The setting up of a corresponding three-dimensional data field for the three-dimensional partial model Depending on the computing power available, TM2 may still be possible. However, partial model TM2 is preferably split into two submodels TM2 ', TM2 ", which are multiplicatively linked with one another, because with sufficient accuracy, a three-dimensional function f, which displays an expected variable TA behind the inter-frame cooling device 5 as a function of expected size TE before the intermediate structure Cooling device 5, the guide speed vL and the amount M of cooling liquid per unit time, are shown as the product of a two-dimensional function g and a one-dimensional function h The function g is in this case of the expected value TE, which is supplied by the partial model TM1, and the The function h depends only on the quantity M of cooling liquid per unit of time, so it can be used $$\mathit{TA}=f\left(\mathit{TE},\mathit{vL},M\right)=G\left(\mathit{TE},\mathit{vL}\right)\cdot H\left(M\right)$$

• TA die Erwartungsgröße für den Energieinhalt des betrachteten Bandpunktes 12, 13, 13' hinter der Zwischengerüst-Kühleinrichtung 5,
• TE die Erwartungsgröße für den Energieinhalt des betrachteten Bandpunktes 12, 13, 13' vor der Zwischengerüst-Kühleinrichtung 5,
• vL die Leitgeschwindigkeit und
• M die Menge an Kühlflüssigkeit, die pro Zeiteinheit auf das Band 2 aufgebracht wird.

Denote this

• TA the expected size for the energy content of the considered band point 12, 13, 13 'behind the inter-frame cooling device 5,
• TE the expected size for the energy content of the considered band point 12, 13, 13 'in front of the inter-frame cooling device 5,
• vL the guide speed and
• M is the amount of cooling fluid applied to the belt 2 per unit of time.

The submodel TM3 has the same structure as the submodel TM1. It models the part of the finishing train 1 which is arranged behind the intermediate stand cooling device 5.

The submodels TM1 to TM3 are connected to each other and concatenated with each other, so that the outputs of the one submodel TM1, TM2 input variables of the next model TM2, TM3 are. By concatenating the partial models TM1 to TM3 with one another, the dimensionality of the modeling problem can already be considerably reduced, namely to the consideration of a three-dimensional and two-dimensional problems. By splitting the three-dimensional problem - keyword partial model TM2 - into a one-dimensional and a two-dimensional function, the complexity can be further reduced. In particular, by reducing the complexity of the three-dimensional problem, the real-time and on-line capability is maintained even when the inter-frame cooling devices 5 and / or the heater 4 are present.

If the inter-frame cooling devices 5 and / or the heating device 4 are present, the guiding variables L * can therefore be calculated on condition that the course of the amount M of cooling fluid per unit time is given. In a second step, the quantity M can then be varied for each intermediate-structure cooling device 5 in order to obtain the expected energy contents of the band points 12, 13, 13 'as far as possible from the corresponding desired energy contents the band points 12, 13, 13 'approximate. The determination of the correct quantities M takes place completely analogously to the determination of the correct quantities of cooling liquid for the cooling devices 7 of the cooling section 6.

It is possible for the control computer 8 to control the finishing train 1 without detecting a measured quantity GM which is characteristic of the actual energy content of the band points 12, 13, 13 'behind the finishing train 1. In a preferred embodiment of the present invention, however, takes the control computer 8 - in this case, of course, after the passage of the respective band points 12, 13, 13 'through the finishing train 1 - according to FIG. 13 in a step S51 for the corresponding band points 12, 13, 13 'in each case counter to a corresponding measured variable GM. For example, the control computer 8 counteracts a corresponding temperature measurement take, which was detected by the temperature measuring device 15.

Furthermore, the control computer 8 determines according to FIG. 13 in a step S52 for at least a portion of the band points 12, 13, 13 '- preferably for all band points 12, 13, 13' - in each case an expected quantity GE '. In general, the control computer determines 8 for each band point 12, 13, 13 'whose expectation size GE' while the respective band point 12, 13, 13 'passes through the finishing train 1. However, it is alternatively possible for the control computer 8 to determine the corresponding expectation variable GE 'before the respective band point 12, 13, 13' passes through the finishing train 1. Each such expected expectation variable GE 'is characteristic of the energy content which is expected for the respective band point 12, 13, 13' at the location xA, to which the desired quantities G * are related. The control computer 8 determines the expected quantities GE 'using the Leitgeschwindigkeitsverlaufs, with which the respective band point 12, 13, 13' actually passes through the finishing train 1.

In the case that the model of the finishing train 1 - regardless of the exact nature of the model of the finishing train 1 - is error-free, the actual energy contents of the band points 12, 13, 13 'determined in step S52 exactly correspond to the actual energy contents determined by the corresponding measured quantities GM are determined. In many cases, however, the model of finishing train 1 is faulty. The reasons for this can be manifold. For example, the modeling may be too simple or the model may have a systematic error, for example the heat transfer may be mis-modeled. In a step S53, the control computer 8 therefore compares the energy content according to the measured variable GM and the energy content according to the corresponding expected variable GE 'with each other. Depending on the comparison of step S53, the control computer 8 automatically carries out at least a part of the control variables in a step S54 L *, which has already been determined by the control computer 8 at the time of the comparison.

The tracking of the control variables L * in the context of step S54, of course, refers only to those control variables L *, which are indeed already determined at this time, but are still pending execution. The step S54 is thus carried out only for guiding variables L * which were determined for band points 12, 13 which have not yet entered the finishing train 1 at the time of the tracking.

It is possible to track all tracked variables L * immediately in their entirety. However, it is preferred to make a smoother transition. For example, the first tracking variable L * can be tracked by 10% of its change, the second tracking variable by 20% of its change, the third tracking variable L * by 30% of its change, etc.

Alternatively or in addition to the presence of step S54, it is possible that the control computer 8 in a step S55 on the basis of the comparison, the determination rule for determining the control variables L * as such adapted. This ensures that future determined control variables L *, which are not yet determined at the time of the comparison of step S53, are determined in an improved manner. The adaptation of the determination rule may include in particular an adaptation of the model of the finishing train 1 and here in particular of the heat transfer model.

In particular, if the expectation quantities GE, GE 'are determined by means of the above-mentioned data field, it is possible to carry out the adaptation of the model of the finishing line 1 for the strip 2, which is currently passing through the finishing line 1, in a simplified manner. For in this case the adaptation can take place, for example, by adding an offset to the actual quantities G before they are used as the input variable of the data field. Alternatively or in addition For example, the leading velocity vL may be scaled by a factor and / or added to an offset before being used as the input of the data field. Alternatively or additionally, an offset can be added to the expected variable GE, GE 'respectively determined using the data field. In particular, the real-time capability of the operating method according to the invention is maintained in this simplified way of adapting the model of the finishing train 1.

It is possible in the context of step S54 to track all the control variables L * which have already been determined at this time, but have not yet been executed, that is to say, for example, the master variable L * for the (first) band point 12 entering the finishing train 1 next. However, based on the comparison of step S53, the control computer 8 automatically performs only those guiding variables L * determined for (second) belt points 13 which at the time of tracking from the entrance of the finishing train 1 have a minimum distance MIN (see FIG FIG. 14 ) exhibit.

Because as in FIG. 14 illustrated, the operating method according to the invention with respect to the Leitgrößenverlaufs a prediction horizon H. The prediction horizon H is determined by the second band point 13, whose master size L * is already determined and which has the greatest distance from the finishing line 1 from the second band points 13 whose guiding variables L * have already been determined. It may be expedient if the control computer 8 automatically uses the comparison to track only those reference variables L * which were determined for second band points 13 which have the minimum distance MIN at the time of tracking from the entrance of the finishing train 1. This will be described below in connection with FIG. 7 be illustrated.

• die Bandpunkte P1 bis P4 bereits aus der Fertigstraße 1 ausgetreten,
• befinden sich die Bandpunkte P5, P6, P7 ... P30 in der Fertigstraße 1,
• tritt der Bandpunkt P31 als nächstes in die Fertigstraße 1 ein und
• erstreckt sich der Prädiktionshorizont H, ausgehend vom Bandpunkt P31, bis zum Bandpunkt P35.

As shown by FIG. 7 are

• the belt points P1 to P4 have already left the finishing train 1,
• are the band points P5, P6, P7 ... P30 in the finishing train 1,
• enters the band point P31 next in the finishing line 1 and
• extends the prediction horizon H, starting from the band point P31, to the band point P35.

Based on the actual temperature, for example, the tape point P2 in front of the finishing train 1 and on the Leitgeschwindigkeitsverlaufs, with the band point P2 has passed the finishing train 1, the control computer 8 determines the temperature for the band point P2 at the exit of the finishing train 1 (ie at location xA) is expected. This corresponds to the step S52 of FIG FIG. 13 , The control computer 8 continues to receive from the temperature measuring device 15, the actual temperature, which is measured for the band point P2. This corresponds to the step S51 of FIG FIG. 13 , Assume that the comparison of step S53 gives a deviation. Despite the deviation of the control computer 8 leaves - for example - the already determined guiding variables L * for the band points P31 to P34 unchanged. Based on the comparison of step S53 in step S54, it only traces the reference variable L * of the band point P35. The control variables L * for subsequent band points P36, P37,..., Which are not yet determined at this time, are determined by the control computer 8 on the basis of a determination rule which it adapts in step S55 on the basis of the comparison of step S53.

It may be permissible in individual cases to also change the guiding variables L * of the band points P31 to P34 as well. In this case, however, the change of the corresponding control variables L * does not take place on the basis of the comparison of step S53, but on the basis of a higher-level control intervention which is specified to the control computer 8 by another control device - for example the control device 8 '- or by an operator.

As already mentioned, the finishing train 1 is usually downstream of a cooling section 6. The cooling section 6 has cooling devices 7. Each cooling device has (at least) one control valve 7 'and a number of spray nozzles 7 "assigned to the respective control valve 7' The amount of cooling fluid delivered locally to the belt 2 is set by means of the respective control valve 7 'The control valves 7' react relatively Calculated from the time at which a control valve 7 'is controlled with a changed manipulated variable S until the time at which the changed control affects the belt 2, there is a dead time T, which is often in the range of seconds In addition, the course of the guide speed vL also influences the passage time of the belt points 12, 13, 13 'through the cooling section 6. It is therefore necessary for the control device 8', which controls the cooling devices 7 of the cooling section 6, not only knows the current value of the guide speed vL, but also their future course. Only then can the control device 8 'of the cooling section 6 react in good time to future changes in the guide speed vL. The control device 8 'of the cooling section 6 must therefore use the control variable L * - and also future upcoming control variables L * - to determine the manipulated variables S for the control valves 7', when the correct amounts of coolant are applied to the "right" places of the belt 2 should. This of course also applies in an analogous form when the control of the cooling section 6 is carried out by the control computer 8.

In the case where inter-frame cooling devices 5 are present, 5 analog dead times occur in the inter-frame cooling devices. Here again, therefore, the characteristic variable course should be used in the determination of the manipulated variables S for the inter-frame cooling devices 5 in order to be able to react in good time to future changes in the guide speed vL. Preferably, therefore, the prediction horizon H is according to FIG. 14 at least that way is large as the above-explained dead time T. Preferably, the prediction horizon H is even greater than the dead time T. If, for example - see FIG. 7 - The dead time T corresponds to the band points P31 to P33, the prediction horizon H should extend over more than two band points, for example according to the representation of FIG. 7 over four band points.

For reasons substantially the same, the minimum distance MIN, within which the tracking of the control variables L * is suppressed, should be at least as long as the dead time T, for example according to FIG FIG. 7 amount to three band points.

The guiding variables L * are determined point by point for the individual band points 12, 13. To determine a continuous Leitgeschwindigkeitsverlaufs is in accordance with FIG. 15 the step S4 is formed in the form of a step S61. In step S61, the control computer 8 chains the determined control variables L * to each other by a spline, so that the chaining results in a control variable course that is continuous and differentiable. Corresponding to this, the so-defined Leitgeschwindigkeitsverlauf is continuous and differentiable.

Alternatively to step S61, a step S62 could be present. In step S62, the control computer 8 determines the corresponding point-specific guide speeds vL on the basis of the guide variables L * determined on a point-by-point basis. In this case, the control computer 8 chains the corresponding guide speeds vL by a spline to each other, so that the chaining results in a continuous and differentiable conduction velocity course.

Steps S61 and S62 are alternative to each other. They are therefore both in FIG. 15 represented, however, both drawn only dashed.

The above-described operating method for the finishing train 1 provides - initially - guiding speeds vL until the last band point 13 of the band 2 has entered the finishing train 1. However, the guide speed vL must be defined as long as at least one band point 12, 13 is located in the finishing train 1, ie even if no further band points 12, 13 run into the finishing train 1 more. It is readily possible to expand the procedure according to the invention accordingly. It is only necessary to consider within the control computer 8 in addition to the band points 12, 13, 13 'for the physically existing band 2 virtual band points, which are attached to the first-mentioned band points. Also for these virtual band points, a corresponding control variable L * is determined. The virtual band points, however, neither an actual size G nor a target size G * is assigned, so that the virtual band points themselves do not contribute to the determination of the corresponding guiding variables L *.

As part of the explanation of the present invention, the Leitgröße L * was further explained in each case in conjunction with the band points 12, 13, which run into the finishing train 1 at certain times. However, this is not to be understood as meaning that the corresponding guiding variables L * are permanently assigned to the corresponding band points 12, 13. The decisive factor is therefore only the assignment of the respective control variable L * at a certain point in time, wherein the time is defined by the fact that the corresponding band point 12, 13 at this time in the finishing train 1 enters.

The present invention has many advantages. In particular, it is possible to predict a Leitgrößen- or Leitgeschwindigkeitsverlauf, which is also observed later in the operation of the finishing train 1 actually. Associated with this results in improved accuracy in maintaining the nominal energy content at the outlet of the finishing train 1 and above In addition, an improved - even significantly improved - accuracy with which the cooling section 6 can be controlled. So it is possible, for example, both a final rolling temperature (at the outlet of the finishing train 1) and a reel temperature (at the outlet of the cooling section 6) to comply with high accuracy.

The above description is only for explanation of the present invention. The scope of the present invention, however, is intended to be determined solely by the appended claims.

Claims (17)

1. Operating method for a production line (1) for rolling a strip (2),

   - wherein an actual value G and a setpoint value G* for the first strip point (12), a number of second strip points (13) and a number of third strip points (13') of the strip (2) are known in each case to a control computer (8) for the production line (1) at the latest at a time point when said first strip point (12) of the strip (2) is still situated in front of the production line (1),

   - wherein the respective actual value G is characteristic of the actual energy content of the respective strip point (12, 13, 13') and the respective setpoint value G* is characteristic of the setpoint energy content of the respective strip point (12, 13, 13'), this applying to each strip point (12, 13, 13'),

   - wherein the respective actual value G relates to a location xE in front of the production line (1) and the respective setpoint value G* relates to a location xA behind the production line (1), this applying to each strip point (12, 13, 13'),

   - wherein the third strip points are fed into the production line before the first strip point,
   characterised in that
   the second strip points are fed into the production line after the first strip point,

   - wherein the control computer (8) determines a command variable L* in each case for the first strip point (12) and at least a subset of the second strip points (13) on the basis of a determining rule that is specific to the respective strip point (12, 13) and before the first strip point (12) is fed into the production line (1),

   - wherein the respective command variable L* is characteristic of the command speed vL at which the control computer (8) operates the production line (1) at the time point when the respective strip point (12, 13) is fed into the production line (1),

   - wherein the control computer (8) determines the respective command speed vL on the basis of the command variable L* that has been determined for the respective strip point (12, 13), and operates the production line (1) at the respective command speed vL at the time point when the respective strip point (12, 13) is fed into the production line (1), and

   - wherein the actual value G and the setpoint value G* of the strip point (12, 13) currently entering the production line (1) at this time point, and the actual value G and the setpoint value G* of at least one strip point (12, 13) that has already entered the production line (1) at this time point, are input into the determining rule for the respective command variable L*.
2. Operating method according to claim 1,
   characterised in that

   - the control computer (8) determines each of the command variables L* on the basis of a multiplicity of individual command variables l*,

   - each individual command variable l* relates in each case to one of the strip points (12, 13, 13') whose actual value and setpoint value G, G* are input into the determination of the respective command variable L*,

   - the control computer (8) determines the respective individual command variable l* for each strip point (12, 13, 13') in such a way that a respective expected value GE matches the corresponding setpoint value G*, and

   - the respective expected value GE is characteristic of an expected energy content that the respective strip point (12, 13, 13') would assume, at that location xA behind the production line (1) to which the currently corresponding setpoint value G* relates, if the control computer (8) were to operate the production line (1) at a command speed vL corresponding to the individual command variable l* during the entire passage of the respective strip point (12, 13, 13') through the production line (1).
3. Operating method according to claim 1,
   characterised in that
   for each strip point (12, 13) whose command variable L* is determined by the control computer (8), said control computer (8)

   - determines an effective actual value G' on the basis of the actual values G that are input into the determination of the command variable L* for the respective strip point (12, 13), and determines an effective setpoint value G'* on the basis of the setpoint values G* that are input into the determination of the command variable L* for the respective strip point (12, 13),

   - determines an expected value GE that is characteristic of an expected energy content which the respective strip point (12, 13) would assume, at that location xA behind the production line (1) to which the effective setpoint value G'* relates, if the control computer (8) were to operate the production line (1) at a command speed vL corresponding to the command variable L* for the respective strip point (12, 13) during the entire passage of the respective strip point (12, 13) through the production line (1), and

   - determines the command variable L* in such a way that the expected value at that location xA behind the production line (1) to which the effective setpoint value G'* relates has the effective setpoint value G'*.
4. Operating method according to claim 1,
   characterised in that

   - when determining the command variables L*, the control computer (8) initially estimates the command variables L* as provisional values,

   - the control computer (8) determines a respective expected value GE for the first strip point (12) and at least a subset of the second and third strip points (13, 13'),

   - each expected value GE is characteristic of an expected energy content that the respective strip point (12, 13, 13') would assume, at that location xA behind the production line (1) to which the currently corresponding setpoint value G* relates, if the control computer (8) were to operate the production line (1) at command speeds vL corresponding to the estimated command variables L* during the entire passage of the respective strip point (12, 13, 13') through the production line (1), and

   - the control computer (8) varies the estimated command variables L*, thereby optimising a target function Z into which the amounts of the differences between the expected values GE and the corresponding setpoint values G* are input.
5. Operating method according to claim 4,
   characterised in that
   a penalty term by means of which changes to the command speed vL are penalised is additionally input into the target function Z.
6. Operating method according to one of the claims 2 to 5,
   c h a r a c t e r i s e d in that

   - the control computer (8) creates a data field beforehand, in which, for a multiplicity of possible command speeds vL and possible actual values G, the control computer (8) stores the expected value GE that is produced for the respective possible actual value G in the case of the respective possible command speed vL, and

   - the control computer (8) determines the command variables L* for the strip points (12, 13) using the data field.
7. Operating method according to claim 6,
   characterised in that
   the control computer (8)

   - determines, for at least a subset of the strip points (12, 13, 13'), a respective expected value GE' which is characteristic of an expected energy content that is expected for the respective strip point (12, 13, 13'), at that location xA behind the production line (1) to which the currently corresponding setpoint value G* relates, as a result of the command speeds vL at which the control computer (8) operates the production line (1) during the entire passage of the respective strip point (12, 13, 13') through the production line (1),

   - receives, after the passage of the respective strip point (12, 13, 13') through the production line (1), a measured value GM which is characteristic of an actual energy content of the respective strip point (12, 13, 13') at that location xA behind the production line (1) to which the corresponding setpoint value G* relates,

   - automatically adapts a model of the production line (1) on the basis of a comparison between the expected energy content and the actual energy content, and

   - adapts the model of the production line (1) by adding an offset to the actual values G when the data field is used, scaling the command speeds vL using a scaling factor and/or adding an offset to said command speeds vL and/or adding an offset to the expected values GE, GE' that were determined using the data field.
8. Operating method according to one of the preceding claims,
   characterised in that
   the actual value G and the setpoint value G* of those strip points (12, 13, 13') that have already entered the production line (1) are only input into the determination of each command variable L* if these strip points (12, 13, 13') have not yet left the production line (1) at the time point for which the respective command variable L* is determined.
9. Operating method according to one of the preceding claims,
   characterised in that
   for at least a subset of the strip points (12, 13, 13'), the control computer (8)

   - determines a respective expected value GE' which is characteristic of an expected energy content that is expected for the respective strip point (12, 13, 13'), at that location xA behind the production line (1) to which the currently corresponding setpoint value G* relates, as a result of the command speeds vL at which the control computer (8) operates the production line (1) during the entire passage of the respective strip point (12, 13, 13') through the production line (1),

   - receives, after the passage of the respective strip point (12, 13, 13') through the production line (1), a measured value GM which is characteristic of an actual energy content of the respective strip point (12, 13, 13') at that location xA behind the production line (1) to which the corresponding setpoint value G* relates, and

   - automatically corrects at least a subset of the already determined command variables L* on the basis of a comparison between the expected energy content and the actual energy content.
10. Operating method according to claim 9,
    characterised in that
    on the basis of the comparison, the control computer (8) automatically corrects only those command variables L* that were determined for the strip points (12, 13) having a minimal distance MIN from the entrance to the production line (1) at the time point of the correction.
11. Operating method according to claim 10,
    characterised in that

    - the control computer (8) or another control device (8') uses the determined command variables L* to determine at least one further actuating variable S, that

    - said further actuating variable S is delayed by a dead time T and acts only locally on the strip (2), and that

    - the minimal distance MIN is specified such that a time difference corresponding to the minimal distance MIN is at least as long as the dead time T.
12. Operating method according to one of the preceding claims,
    characterised in that

    - the control computer (8) or another control device (8') uses the determined command variables L* to determine at least one further actuating variable S, that

    - said further actuating variable S is delayed by a dead time T and acts only locally on the strip (2), and that

    - the first strip point (12) and that subset of the second strip points (13) for which the respective command variable L* was determined before the first strip point (12) was fed into the production line (1) correspond to a prediction horizon H that is at least as long as the dead time T.
13. Operating method according to one of the preceding claims,
    characterised in that
    the control computer (8) concatenates the determined command variables L* or the corresponding command speeds vL by means of a spline, such that a command-speed profile produced by the concatenation is constant and differentiable.
14. Operating method according to one of the preceding claims,
    characterised in that
    the control computer (8) performs the determination of the command variables L* in the context of a precalculation online or in real time.
15. Computer program comprising machine code (11), which can be directly executed by a control computer (8) for a production line (1) for rolling a strip (2) and whose execution by the control computer (8) causes the control computer (8) to operate the production line (1) in accordance with an operating method having all the steps of an operating method according to one of the preceding claims.
16. Control computer for a production line (1) for rolling a strip (2),
    characterised in that
    the control computer is so designed as to operate the production line (1) in accordance with an operating method having all the steps of an operating method according to one of the claims 1 to 14.
17. Production line for rolling a strip (2),
    characterised in that
    the production line is equipped with a control computer (8) according to claim 16.

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