Rolling with frequency behavior in mind

Abstract

A metal strip (1) is rolled in a rolling stand (2) and is fed into the rolling stand by an input device (3). The rolled metal strip is discharged from the rolling stand by an output device (4). A control device (9) periodically determines a setpoint value for a control mechanism based on the final thickness deviation (δd2) of a section (12) of the metal strip from the discharge side setpoint thickness (d2*) of the metal strip and outputs the determined setpoint value to the control mechanism. The control mechanism comprises: an input device; an adjustment device (13) for the rolling gap of the rolling stand; a drive (14) for driving the rolls of the rolling stand; and / or an output device. For the input device, the drive and the output device, the setpoint value is a setpoint speed or a setpoint torque. For the adjustment device, the setpoint value is a rolling gap setpoint value. The control device determines at least one of the setpoint values based on the amount of the final thickness deviation, taking into account the description of the inverse frequency behavior of the corresponding control mechanism.

Description

Technical Field

[0001] The invention proceeds from a method for operating a rolling mill.

[0002] - wherein a feed device arranged upstream of a rolling stand of the rolling mill feeds the metal strip to the rolling stand,

[0003] - wherein rolling stands roll metal strips,

[0004] - wherein a discharge device arranged downstream of the rolling stand discharges the metal strip from the rolling stand,

[0005] - wherein the control device of the rolling mill periodically determines a corresponding number of setpoint values for a certain number of control elements, depending on a corresponding number of final thickness deviations of a certain number of metal strip sections from the desired thickness of the metal strip at the discharge side, and outputs the determined setpoint values to the control elements,

[0006] - wherein the control mechanism comprises: an input device; and / or an adjusting device of the rolling stand for setting the rolling gap of the rolling stand; and / or a drive of the rolling stand for driving the rollers of the rolling stand; and / or an output device,

[0007] - The setpoint value for the input device is the setpoint speed or the setpoint torque, the setpoint value for the adjustment device is the rolling gap setpoint value, the setpoint value for the drive is the roller peripheral speed or the rolling torque, and the setpoint value for the output device is the setpoint speed or the setpoint torque.

[0008] The present invention is further based on a control program comprising a machine code that can be processed by a control device for a rolling mill, wherein the machine code is processed by the control device, which operates the rolling mill according to such an operating method.

[0009] The present invention is further based on a control device for a rolling mill, wherein the control device is programmed with such a control program so that the control device operates the rolling mill according to such an operating method.

[0010] The invention further proceeds from a rolling plant for rolling metal strip.

[0011] - wherein the rolling mill comprises at least one rolling stand, an inlet device arranged upstream of the rolling stand, an outlet device arranged downstream of the rolling stand, and a control device,

[0012] - wherein the feed device feeds the metal strip into the rolling stand,

[0013] - wherein rolling stands roll metal strips,

[0014] - wherein the discharge device discharges the metal strip from the rolling stand,

[0015] - wherein the control device operates the rolling mill according to this operating method.

[0016] When manufacturing metal strip, after casting the slab, the slab is first hot rolled to produce a hot strip. The thickness of the hot strip is usually in the range of a few millimeters, sometimes slightly above or below this depending on the manufacturing method, for example, between 1.0 mm and 20 mm in conventional hot rolling facilities and between 0.6 mm and 6 mm in so-called ESP facilities. In some cases, the hot strip is further processed without further thickness reduction. In other cases, the strip thickness is further reduced in a cold rolling mill after hot rolling. The purpose of cold rolling is to produce a cold-rolled metal strip whose final thickness is as good as possible and with as little deviation as possible from the target thickness.

[0017] Generally speaking, finished hot strips—that is, after hot rolling but before rolling in a cold rolling mill—have thickness deviations. These thickness deviations often have not only a periodic component but also a random component. If these deviations are not compensated, the metal strip will also have such deviations after cold rolling. Although the absolute size of these deviations is smaller than for hot strips, the relative deviations are retained. Thus, for example, if a metal strip has a thickness of 3.0 mm before cold rolling and has a thickness deviation in the range of 30 μm, and furthermore, the metal strip has a thickness of 1.0 mm after cold rolling, then the metal strip will have a thickness deviation in the range of 10 μm after cold rolling without compensating for the thickness deviations. Background Art

[0018] In order to compensate for such deviations, various operating methods are known in the prior art.

[0019] For example, EP 0 435 595 A2 discloses detecting the thickness of the rolled metal strip on the discharge side of the rolling stand and regulating the thickness of the rolling stand. Furthermore, tension fluctuations are compensated, as these also affect the thickness of the rolled metal strip. To achieve relatively dynamic tension regulation, rollers or similar elements are provided between the feed device and the rolling stand, on the one hand, and between the rolling stand and a receiving device arranged downstream of the rolling stand, on the other hand, by means of which the metal strip can be deflected in the rolling stand before and / or after rolling. The operating method of EP 0 435 595 A2 is based on the idea that regulation by the feed device and the receiving device itself is very slow and that additional rollers can increase the dynamics of regulation. EP 0 435 595 A2 also describes an operating method in which the thickness and speed of the metal strip are detected on the inlet side of the rolling stand and used to determine the adjustment of the rolling stand.

[0020] EP 3 332 883 A1 also discloses detecting the thickness of the rolled metal strip on the discharge side of the rolling stand and performing thickness control of the rolling stand. Periodic deviations are separated from random deviations. Periodic deviations are considered to be caused by eccentricity of the rolls of the rolling stand. Corrections to the rolling stand settings are then made accordingly.

[0021] In JP 58 068 414 A, the thickness of the unrolled metal strip is detected at the inlet side of the rolling stand and averaged over a certain length unit. The average value is used to control the adjustment of the rolling stand.

[0022] In an earlier European patent application 20184420.6 filed on July 7, 2020, by Primetals Technologies Deutschland GmbH, a method for operating a rolling mill is described, in which the thickness of a plurality of rolling stock sections is detected separately on the inlet side of the rolling stand and, based on this, pre-control values for the rolling stand and / or the feed device are determined. The regulated variables may be the rolling gap, feed speed, tension, rolling torque, and rolling speed. Thickness measurement can be performed on the discharge side. Within the scope of determining the pre-control values, the frequency behavior of the feed device and / or the rolling stand is taken into account. Patent application 20184420.6 was not published at the filing date and is therefore not generally accessible prior art. Summary of the Invention

[0023] The object of the present invention is to provide possibilities by means of which excellent compensation of thickness deviations of the metal strip on the discharge side can be achieved.

[0024] This object is achieved by an operating method for a rolling mill having the features of claim 1. Advantageous embodiments of the operating method are the subject matter of dependent claims 2 to 10.

[0025] According to the invention, an operating method of the type mentioned at the outset is designed in such a way that the control device determines at least one of the setpoint values as a function of the amount of the final thickness deviation, taking into account the inverse frequency behavior describing the corresponding control or actuating element.

[0026] The present invention demonstrates that the scale (Ausmaß) by which a specific final thickness deviation is corrected depends not only on the final thickness deviation itself, but also on the frequency spectrum of multiple final thickness deviations. In particular, high-frequency final thickness deviations are generally compensated only within a smaller range and with a greater phase delay than low-frequency final thickness deviations. To compensate for high-frequency final thickness deviations over the full range and without phase delay, the frequency behavior of the control mechanism must be taken into account. In some cases, the measured value acquisition exhibits a frequency behavior that can also be taken into account. This consideration is based on a description of the inverse frequency behavior of the control mechanism (and, in some cases, the measuring device).

[0027] In many cases, the magnitude of the final thickness deviation is equal to 1. In this case, for example, it is possible for the control device to determine the final thickness deviation for the corresponding cycle—in this case, a single final thickness deviation—based on the final entry thickness of the metal strip section, taking into account the entry speed of the metal strip section into the rolling stand and the exit speed of the metal strip section from the rolling stand, using the mass flow equation. The metal strip section to which the determined final thickness deviation relates is, in this case, the currently rolling section of the metal strip. This operating method implements so-called MFC (mass flow control).

[0028] The entry speed is the speed at which the metal strip enters the rolling gap. It differs from the roller tip speed by a factor, often called the lag. Similarly, the discharge speed is the speed at which the metal strip exits the rolling gap. It also differs from the roller tip speed by a factor, often called the lead.

[0029] The entry speed can also deviate from the feed speed. This is because the feed speed is the speed at which the metal strip is delivered by the feed device. In the event of a deviation, this deviation causes a change in the tension acting on the metal strip at the entry side of the rolling stand. Similarly, the discharge speed can also deviate from the delivery speed. This is because the delivery speed is the speed at which the metal strip is delivered by the delivery device. In the event of a deviation, this deviation causes a change in the tension acting on the metal strip at the discharge side of the rolling stand.

[0030] In the case of MFC, it is possible that the final entry-side thickness of a metal strip segment is the thickness of the metal strip segment detected at the entry side of the rolling stand for the current rolling segment of the metal strip prior to the corresponding cycle. In this case, a single entry-side thickness value is detected for the respective metal strip segment and used directly as the final entry-side thickness of the respective metal strip segment. Alternatively, it is possible for the control device to determine the final entry-side thickness of the metal strip segment by filtering the thicknesses detected at the entry side of the rolling stand for a plurality of metal strip segments.

[0031] As already mentioned, the entry-side thickness of the metal strip section is detected at a point in time before the final thickness deviation is determined. However, in conjunction with generally known path tracking, it is easy to determine the point in time at which the corresponding metal strip section was rolled. A similar approach applies even when using multiple thicknesses detected at the entry side.

[0032] The filtering is typically low-pass filtering, which removes high-frequency fluctuations. It is preferably zero-phase filtering, which is generally known to those skilled in the art. Purely by way of example, the so-called IIR (infinite impulse response) filter can be mentioned. Another possibility for implementing zero-phase filtering is convolution of a symmetrical impulse response using an FIR filter (FIR = finite impulse response).

[0033] Alternatively, it is possible that, as in the case of MFC, the number of the final thickness deviations per cycle is equal to 1, but that this final thickness deviation relates to a metal strip section rolled before the current rolling section of the metal strip. In this case, so-called FBC (feedback control) is implemented.

[0034] In the case of FBC, it is possible to arrange a measuring device between the rolling stand and the discharge device. This measuring device detects the discharge thickness and inputs it to the control device. The final thickness deviation is determined based on the detected discharge thickness and the discharge target thickness. Alternatively, in the case of FBC, it is possible for the control device to determine the final thickness deviation by filtering a corresponding number of temporary thickness deviations of a plurality of metal strip sections from the discharge target thickness. The filtering is typically low-pass filtering, which removes high-frequency fluctuations.

[0035] The filtering is preferably a zero-phase filtering. In this case, a first portion of the temporary thickness deviations relates to sections of the metal strip that have already been rolled, but after the section of the metal strip to which the final thickness deviation relates. Likewise, a second portion of the temporary thickness deviations relates to sections of the metal strip that have not only already been rolled, but even before the section of the metal strip to which the final thickness deviation relates.

[0036] For a first portion of these temporary thickness deviations, the control device determines the corresponding temporary thickness deviations based on a corresponding, consistent final entry thickness of the metal strip, taking into account the entry speed of the corresponding section of the metal strip into the rolling stand and the exit speed of the corresponding section of the metal strip from the rolling stand, using the mass flow equation. Because the corresponding sections have already been rolled, the corresponding speeds are known. Therefore, determining these temporary thickness deviations is possible in any case.

[0037] Similar to the operating method in the case of MFC, it is possible that for a first portion of the plurality of temporary thickness deviations, the corresponding final entry-side thickness of the section of the metal strip is the thickness of the corresponding section of the metal strip detected at the entry side of the rolling stand for the corresponding section of the metal strip. Alternatively—again similar to the operating method in the case of MFC—it is possible that the control device determines the corresponding final entry-side thickness of the corresponding section of the metal strip by filtering the thicknesses detected at the entry side of the rolling stand for a plurality of corresponding sections of the metal strip.

[0038] The same procedure can be used for the multiple temporary thickness deviations of the already mentioned second part of these temporary thickness deviations. It is therefore possible for the control device to determine these temporary thickness deviations here as well based on the mass flow equation. However, preferably, a measuring device arranged between the rolling stand and the discharge device detects the discharge-side thickness for multiple sections of the metal strip and inputs this to the control device. In this case, the second part of these temporary thickness deviations can relate to sections of the metal strip that are rolled before the metal strip section to which the final thickness deviation relates. For the second part of the temporary thickness deviations, the control device can therefore determine the corresponding temporary thickness deviation based on the respectively detected discharge-side thickness and the discharge-side target thickness.

[0039] Alternatively, it is possible that the number of final thickness deviations per cycle is greater than 1. In this case, all of the associated sections of the rolling stock have already been rolled. A plurality of setpoint values are determined in the result for a final thickness deviation that relates to a location downstream of the rolling stand.

[0040] Alternatively, when using multiple final thickness deviations, it is also possible for the control device to determine the multiple final thickness deviations by filtering a corresponding number of temporary thickness deviations of a plurality of sections of the metal strip from the desired thickness of the metal strip at the discharge end. The filtering is typically a low-pass filter, which removes high-frequency fluctuations.

[0041] Preferably, the filtering is a zero-phase filtering. In this case, the control device—as before—determines a first part of the plurality of temporary thickness deviations from a corresponding corresponding final entry-side thickness of the metal strip, taking into account the entry speed of the corresponding section of the metal strip into the rolling gap and the exit speed of the corresponding section of the metal strip from the rolling gap, according to the mass flow equation.

[0042] It is also possible - as before - for a first part of a plurality of temporary thickness deviations, the corresponding final entry-side thickness of the section of the metal strip can alternatively be the thickness of the corresponding section of the metal strip detected for the corresponding section of the metal strip on the entry side of the rolling stand, or the control device can determine the corresponding final entry-side thickness of the corresponding section of the metal strip by filtering a plurality of thicknesses detected for a plurality of corresponding sections of the metal strip on the entry side of the rolling stand.

[0043] As before, a measuring device is preferably arranged between the rolling stand and the discharge device. This measuring device can detect a measured value for each of the respective final thickness deviations for a plurality of rolled sections of the metal strip. This makes it possible for the control device to use the measured values detected for the respective sections for the second portion of the plurality of temporary thickness deviations.

[0044] There are various possibilities for the manner and method of taking into account the inverse frequency behavior.

[0045] When the number of final thickness deviations is greater than 1, it is feasible to preset the description of the inverse frequency behavior of the corresponding control mechanism of the control device as a corresponding frequency process (Frequenzgang), and the control device obtains the corresponding rated value by transforming the trends of multiple final thickness deviations into a frequency range, subsequently multiplying the trends of the transformed final thickness deviations by the corresponding frequency process, and subsequently inversely transforming them into a time range.

[0046] In general, it is known that multiplication in the frequency range corresponds to convolution in the time range. If the number of final thickness deviations is greater than one, it is alternatively possible to predefine the description of the inverse frequency behavior of the corresponding control element of the control device as a corresponding convolution kernel, and for the control device to determine the corresponding setpoint value by convolving the course of the multiple final thickness deviations with the corresponding convolution kernel.

[0047] However, regardless of the magnitude of the final thickness deviation—that is, not only for the case where the magnitude is equal to 1, but also for the case where the magnitude is greater than 1—it is always possible to:

[0048] - presupposing a description of the inverse frequency behavior of the corresponding control mechanism of the control device by means of a corresponding inverse model;

[0049] - the control device inputs the final thickness deviation of a section of the metal strip into a corresponding inverse model; and

[0050] The control device, using the input final thickness deviation, uses the corresponding inverse model to track the corresponding internal state of the corresponding inverse model on the one hand and to determine the corresponding setpoint value on the other hand.

[0051] This operating method is currently preferred. In particular, it minimizes the computational effort, since the control device only needs to know a single final thickness deviation. This operating method is therefore associated with minimal computational effort.

[0052] The detection of the frequency progression and the resulting inverse model, or parameterization, or enhanced determination of multiple individual frequency ranges or determination of the convolution kernel can be performed automatically. In particular, during the ongoing operation of the rolling mill, defined small disturbances can be applied to the desired rolling gap value of the rolling stand or another controlled variable of the control system. These disturbances manifest themselves on the discharge side of the rolling stand as consistent fluctuations in the discharge thickness of the metal strip. If a measuring device is arranged downstream of the rolling stand, by means of which the discharge thickness is detected, the frequency progression can be determined automatically by combining the evaluation of the applied disturbances on the one hand and the fluctuations in the discharge thickness on the other. This is generally known to those skilled in the art.

[0053] This object is further achieved by a control program having the features of claim 11. According to the invention, processing of the computer program causes the control device to operate the rolling mill according to the operating method according to the invention.

[0054] This object is further achieved by a control device having the features of claim 12. According to the invention, the control device is programmed with a control program according to the invention so that it operates the rolling mill according to the operating method according to the invention.

[0055] This object is further achieved by a rolling mill having the features of claim 13. According to the invention, a control device operates the rolling mill according to the operating method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The above-mentioned characteristics, features and advantages of the present invention and the manner and method of achieving them will become clearer and more apparent in the following description of the embodiments, which are explained in more detail in conjunction with the accompanying drawings. In this case, in the schematic diagram:

[0057] Figure 1 The rolling facility is shown;

[0058] Figure 2 A flow chart is shown;

[0059] Figure 3 The metal strip is shown from above;

[0060] Figure 4 The structural configuration of the control device is shown;

[0061] Figure 5 Shown Figure 4 A feasible design solution;

[0062] Figure 6 Shown Figure 5 A revised plan;

[0063] Figure 7 Shown Figure 4 Another feasible design solution:

[0064] Figure 8 Shown Figure 7 A revised plan;

[0065] Figure 9 A portion of a metal strip is shown; and

[0066] Figure 10 The overall structural configuration of the control device is shown. DETAILED DESCRIPTION

[0067] according to Figure 1 The rolling mill for rolling a metal strip 1 has a rolling stand 2. The rolling stand 2 can be a cold rolling stand in particular, in which the metal strip 1 is subsequently cold-rolled. Figure 1 The working rolls in the center figure also include at least two backup rolls. For example, it can be configured as a quarter-roll stand. In some cases, the rolling stand 2 has even more rolls. For example, the rolling stand 2 can be configured as a sextower stand (two working rolls, two intermediate rolls, two backup rolls), a 12-roller rolling stand, or a 20-roller rolling stand. The metal strip 1 can be made of steel, aluminum, or another metal, such as copper or brass.

[0068] A metal strip 1 is rolled in a rolling stand 2. During the rolling of the metal strip 1, the metal strip 1 enters the rolling stand 2 at an entry velocity v1 and exits the rolling stand 2 at a discharge velocity v2. During the rolling of the metal strip 1, the individual rolls of the rolling stand 2 rotate at a roll tip velocity vU. The roll tip velocity vU generally differs from both the entry velocity v1 and the discharge velocity v2 by a corresponding factor. The factor by which the roll tip velocity vU differs from the entry velocity v1 is generally referred to as lag. Similarly, the factor by which the roll tip velocity vU differs from the discharge velocity v2 is generally referred to as lead.

[0069] The rolling mill also has an infeed device 3. The infeed device 3 is arranged upstream of the rolling stand 2. The metal strip 1 is fed to the rolling stand 2 by the infeed device 3 at an infeed speed v3. The infeed device 3 is arranged upstream of the rolling stand 2. Figure 1 The feed device 3 can also be designed as a capstan. However, the feed device can also be designed differently, for example as a transmission or as a rolling stand different from the rolling stand 2. The feed device 3 can also be designed as a so-called S-roller, that is, a plurality of rollers over which the metal strip 1 is guided in an S-shape.

[0070] The rolling mill also has a discharge device 4. The discharge device 4 is arranged downstream of the rolling stand 2. The metal strip 1 is discharged from the rolling stand 2 at a discharge speed v4 by the discharge device 4. The discharge device 4 is arranged downstream of the rolling stand 2. Figure 1 The discharge device 4 can also be designed as a capstan. However, the discharge device can also be designed differently, for example as a drive or as a rolling stand different from the rolling stand 2. The discharge device 4 can also be designed as a so-called S-roller, that is, a plurality of rollers over which the metal strip 1 is guided in an S-shape.

[0071] The input speed v3 is the speed at which the metal strip 1 is fed into the rolling stand 2 by the input device 3. This input speed may deviate from the input speed v1. In the event of a deviation, this deviation causes a change in the tension acting on the metal strip 1 at the input side of the rolling stand 2. Similarly, the output speed v4 is the speed at which the metal strip 1 is discharged from the rolling stand 2 by the discharge device 4. This output speed may deviate from the discharge speed v2. In the event of a deviation, this deviation causes a change in the tension acting on the metal strip 1 at the discharge side of the rolling stand 2.

[0072] It is possible to arrange a measuring device 5 between the inlet device 3 and the rolling stand 2. By means of the measuring device 5, as long as it is present, a measured value for the thickness d1 of the metal strip 1 is periodically and repeatedly detected on the inlet side of the rolling stand 2. Furthermore, a further measuring device 6 can additionally be present, by means of which a measured value for the speed of the metal strip 1 is repeatedly detected on the inlet side of the rolling stand 2. This measured value can be used, in particular, as a measured value for the inlet speed v1.

[0073] according to Figure 1 Furthermore, a further measuring device 7 can be arranged between the rolling stand 2 and the discharge device 4. By means of the measuring device 7, as long as it is present, a measured value for the thickness d2 of the metal strip 1 is periodically and repeatedly detected on the discharge side of the rolling stand 2. Furthermore, a further measuring device 8 can additionally be present, by means of which a measured value for the speed of the metal strip 1 is repeatedly detected on the discharge side of the rolling stand 2. This measured value can be used, in particular, as a measured value for the discharge speed v2.

[0074] The respectively detected thickness values d1, d2 and also the respectively detected values for the inlet speed v1 and the outlet speed v2 are input to a control device 9, which is also a component of the rolling mill. The control device 9 is programmed with a control program 10. The control program 10 includes a machine code 11, which can be processed by the control device 9. The programming of the control device 9 with the control program 10 or the processing of the machine code 11 by the control device 9 causes the control device 9 to operate the rolling mill according to an operating method, which is first described in conjunction with Figure 2And then there are other figures to explain in detail.

[0075] according to Figure 2 The control device 9 repeatedly and periodically executes steps S1 to S4. The control device 9 usually executes steps S1 to S4 in a strictly rhythmic manner, that is, with a fixed cycle time T. The cycle time T is generally much lower than 1 second, in particular lower than 100 ms. For example, it can be 8 ms.

[0076] The metal strip 1 may correspond to Figure 3 The view in is divided into a certain number of segments 12. This division is only virtual, i.e. purely imaginary. The segments 12 are Figure 3 The middle parts are supplemented with lower case letters (a, b, etc.) so that they can be distinguished from each other when necessary. Figure 3 The arrow in represents the transport direction of the metal strip 1 .

[0077] relatively Figure 2 The following embodiments and also the further figures relate to a single cycle, ie one execution of steps S1 to S4. In the corresponding cycle, in the rolling stand 2 corresponding to Figure 3 FIG. 1 shows a single section 12 of a metal strip 1 being rolled. The currently rolled section 12 of the metal strip 1 is subsequently designated by reference numeral 12a. In the previous cycle, the preceding section 12 of the metal strip 1 was rolled. In the next cycle, the following section 12 of the metal strip 1 is rolled. Similar embodiments apply to the remaining sections 12 of the metal strip 1.

[0078] according to Figure 2 In step S1, the control device 9 receives the respectively detected thickness values d1 and d2, and possibly also the respectively detected values for the entry speed v1 and the exit speed v2. During this cycle, the rolling section 12a is rolled. The detected thickness value d1 relates to another section 12 of the metal strip 1, which is rolled after the currently rolled section 12 of the metal strip 1. For example, the thickness value d1 may relate to the section 12 of the metal strip 1 marked with the reference numeral 12b. The detected thickness value d2, in contrast, relates to the section 12 of the metal strip 1 that is rolled before the currently rolled section 12 of the metal strip 1. For example, the thickness value d2 may relate to the section 12 of the metal strip 1 marked with the reference numeral 12c. The detected speeds v1 and v2 again relate to the currently rolled section 12a.

[0079] In step S2, the control device 9 selects a number of final thickness deviations δd2. The final thickness deviations δd2 selected in step S2 are the final thickness deviations δd2 used in step S3 and, based thereon, in step S4. Generally, the number of selected thickness deviations δd2 is equal to one. The control device 9 selects a single final thickness deviation δd2 in step S2. However, embodiments of the present invention are also possible in which the control device 9 selects multiple final thickness deviations δd2 in step S2. In this case, each individually selected final thickness deviation δd2 relates to one of a corresponding number of segments 12 of the metal strip 1. In the case of a single selected final thickness deviation δd2, the selected final thickness deviation δd2' relates to either segment 12a or segment 12c.

[0080] Each individual final thickness deviation δd2 is the difference between the final thickness d2' of the metal strip 1 on the discharge side of the rolling stand 2 and the associated target thickness d2* of the metal strip 1 on the discharge side of the rolling stand 2. The corresponding final thickness d2' is therefore the respective thickness d2' of the metal strip 1 after rolling in the rolling stand 2. The respective final thickness d2' relates to the respective section 12 of the metal strip 2. Possible implementations of step S2 will become clear from the following detailed description.

[0081] In step S3, the control device 9 determines a corresponding number of setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* for a certain number of control elements 13, 14, 3, 4. Within the context of determining the setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4*, the control device 9 uses the aforementioned number of final thickness deviations δd2. In step S4, the control device 9 outputs the determined setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* to the control elements 13, 14, 3, 4 (more precisely, to the regulators arranged upstream of the control elements 13, 14, 3, 4). The setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* can be basic setpoint values, i.e., setpoint values which completely or at least approximately completely determine the resulting setpoint value for the respective control element 13, 14, 3, 4. However, these are often additional setpoint values, i.e., setpoint values which are connected to or superimposed on such a basic setpoint value.

[0082] The number and design of the control devices 13, 14, 3, 4 can be selected as needed. For example, one of the control devices 13, 14, 3, 4 can be the adjustment device 13 of the rolling stand 2, which is used to set the rolling gap of the rolling stand 2. In this case, the associated setpoint value s* is the rolling gap setpoint value s*, which is output, for example, to a so-called HGC (hydraulic gap control). Alternatively or additionally, one of the control devices 13, 14, 3, 4 can be the drive 14 of the rolling stand 2, which is used to drive the rolls of the rolling stand 2. In this case, the associated setpoint values vU*, M2* are the roller circumferential speed vU* or the rolling torque M2*. Alternatively or additionally, one of the control devices 13, 14, 3, 4 can be the input device 3. In this case, the associated setpoint values v3*, M3* are the setpoint speed v3* or the setpoint torque M3*. Alternatively or additionally, one of the control devices 13, 14, 3, 4 can be the output device 4. In this case, the associated setpoint value v4*, M4* is a setpoint speed v4* or a setpoint torque M4*. In the case of very small discharge-side thickness d2, it may sometimes be useful to control the input device 3 and / or the output device 4 accordingly instead of the adjustment device 13 and the drive 14 of the rolling stand 2, so that the tension is varied in a targeted manner on the inlet and / or discharge side of the rolling stand 2 to compensate for thickness tolerances of the metal strip 1.

[0083] In many cases, it is expedient for the control device 13, 14, 3, 4 to comprise either the adjusting device 13 of the rolling stand 2, the drive 14 of the rolling stand 2, and the input device 3, or the adjusting device 13 of the rolling stand 2, the drive 14 of the rolling stand 2, and the output device 4. Accordingly, the control device 9 receives as setpoint values a setpoint value s* for the rolling gap and a setpoint value M2* for the rolling torque or a setpoint value vU* for the roller peripheral speed vU, and furthermore either a setpoint value v3* or M3* for the input device 3 or, alternatively, a setpoint value v4* or M4* for the output device 4.

[0084] The core of the invention is the following form and method, by which the control device 9 uses the final thickness deviation δd2 of the aforementioned number when the setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* are known in step S3. Figure 4The determination of the rolling gap setpoint value s* for the adjustment device 13 is explained in more detail. Similar embodiments apply to the other control devices 3, 4, 14 and the other setpoint values M2*, vU*, v3*, M3*, v4*, M4*. Furthermore, the present invention is explained in conjunction with a single final thickness deviation δd2. Similar embodiments apply to the use of multiple final thickness deviations δd2.

[0085] according to Figure 4 , the control device 9 includes a regulator block 15 and a modification block 16. The division of the regulator block 15 and modification block 16 facilitates the explanation of the present invention. In principle, the regulator block 15 and modification block 16 can also be combined into a common block. The order of these blocks 15 and 16 can also be interchanged by appropriately adapting the parameters input to and provided by the respective blocks 15 and 16. The regulator block 15 and modification block 16 are typically implemented as software blocks by the control device 9 based on the implementation of the control program 10.

[0086] The final thickness deviation δd2 is input to a controller block 15. The controller block 15 determines a provisional setpoint value s'* based on a controller characteristic determined by the execution of the controller block 15. The controller characteristic can be implemented, for example, in the form of a P controller (i.e., proportional controller), a PI controller (i.e., proportional-integral controller), a controller structure implemented using an observer, etc. Such a controller block 15 can also be designed according to the prior art.

[0087] The temporary setpoint value s'* is passed from the controller block 15 to the modification block 16. The modification block 16 modifies the temporary setpoint value s'* and thus determines the (final) setpoint value s*. In this case—and this is crucial—the description of the inverse frequency behavior of the control device 13 is taken into account in the modification block 16.

[0088] As a result, the control device 9 is thus provided with the following description, which directly characterizes the frequency behavior of the adjusting device 13. In other words, the frequency behavior of the adjusting device 13 can be determined from the aforementioned description. The control device 9 thus not only receives the setpoint value s* in a form and manner that takes into account the corresponding inverse frequency behavior. Rather, the control device 9 explicitly knows this corresponding inverse frequency behavior. The control device 9 thus knows the characteristic variables that define this inverse frequency behavior. This will be explained in detail later with respect to the rolling stand 2 and its adjustment.

[0089] The rolling stand 2 can be modeled in various ways. In the simplest case, the rolling stand 2 is modeled as a PT1 link (PT1-link). Alternatively, a higher-level modeling is conceivable. This modeling describes such a rolling stand 2, possibly including its controller (HGC).

[0090] The frequency behavior of the rolling stand 2 can be described, for example, by a transfer function. In the following, as is generally the case, this transfer function is designated G. The Laplace operator is designated L. This approach is currently adopted because the reference symbol s* has been assigned to the rolling gap setpoint value. In the usual manner, the actual rolling gap value must therefore be designated by the reference symbol s. However, the Laplace operator is also often designated by s. Therefore, using the reference symbols s* for the rolling gap setpoint value and s for the Laplace operator could lead to unnecessary confusion.

[0091] Using the mentioned determination the transfer function G(L) can be described as

[0092] (1).

[0093] In this case, b i (i=1, 2...m) and c j (j=1, 2...n) are constant coefficients. The degree (Grad) m of the numerator polynomial is at most as large as the degree n of the denominator polynomial. When the rolling stand 2 is modeled as a PT1 link, the transfer function G(L) is obtained as

[0094] (2).

[0095] Here, T′ is a characteristic time constant of the adjustment device 13 .

[0096] For the corresponding inverse transfer function G -1 (L) Generally applicable:

[0097] (3).

[0098] Therefore, the inverse transmission behavior G -1 (L) is clearly defined. When the rolling stand 2 is modeled as a PT1 link, the corresponding inverse transfer function G is obtained. -1 (s) just as:

[0099] (4).

[0100] However, when the inverse transfer function G -1 Even when (L) is accurately modeled, the modeled behavior of the rolling stand 2 is often unstable. In some cases, the behavior of the real rolling stand 2 may even become unstable. For example, the inversion of the PT1 link results in a PD link. The PD link particularly emphasizes high frequencies. The theoretically known initial signal of the PD link may not be converted in practice. The reason for this is the adjustment limits of the control device 13. To ensure stability and feasibility, the inverse transfer function G is therefore -1The denominator polynomial of (L) is expanded by a component that is related to the inverse transfer function G -1 The frequency behavior of the rolling stand 2 is proportional to the highest power of L in the numerator of (L). This is a method known to those skilled in the art. For this purpose, reference can be made to the specialist book "Stable Neural Online Identification and Compensation of Static Nonlinearities" by Thomas Fren. The inverse modeling of the frequency behavior of the rolling stand 2 is thus performed using a modified inverse transfer function G -1 (L) is described by the formula

[0101] (5).

[0102] T″ is a short time, i.e., a time that is significantly smaller than the characteristic time constant T′ of the rolling stand 2. The smaller this time T″ can be chosen, the better the inverse frequency behavior of the rolling stand 2 is modeled. In practice, the time T″ is chosen to be equal to the cycle time T or approximately equal to the cycle time T.

[0103] Based on the above situation, it is possible that the control device 9 corresponds to Figure 4 The diagram in FIG. 1 prescribes a corresponding inverse model of the control device 13 by correspondingly executing the modification block 16. The modification block 16 thus corresponds to an inverse model. As explained above, the modification block 16 or the inverse model describes the inverse frequency behavior of the control device 13. Transport times, constant dead times, and similar times can be taken into account within or outside the modification block 16 as required.

[0104] The selected final thickness deviation δd2 of the corresponding section of the metal strip 1 is fed to the modification block 16 at a rate of cycle time T. The control device 9 uses the modification block 16 to determine the desired value s* for the adjustment device 13, taking into account the internal state Z of the inverse model 16, and outputs the desired value s* to the adjustment device 13. Furthermore, the control device 9 uses the selected final thickness deviation δd2 and the previous internal state Z of the modification block 16 to track this internal state Z. Taking into account and tracking the internal state Z is necessary because otherwise the modification block 16 would not be able to store knowledge of the previous course of the final thickness deviation and, therefore, would not be able to model a frequency behavior, but only a purely proportional behavior. The state Z can alternatively be a scalar or vector variable.

[0105] Similar embodiments, as already mentioned, apply to the other control devices 14 , 3 , 4 .

[0106] Specific possible embodiments of the present invention will be explained in detail below in conjunction with other figures. Within the scope of these embodiments, it is always assumed that the number of selected final thickness deviations δd2 of the corresponding period is equal to 1.

[0107] Corresponding to Figure 5 , a determination block 17 is arranged upstream of the controller block 15. The determination block 17 is implemented by the control device 9—similar to the controller block 15 and the modification block 16—mostly as a software block based on the implementation of the control program 10. A final entry thickness d1' is input to the software block 17. The final entry thickness d1' relates to the section 12 of the metal strip 1 that is rolled in the respective cycle, namely, section 12a.

[0108] In accordance with Figure 5 Within the scope of the embodiment, the final entry-side thickness d1' is directly identical to the thickness d1 detected on the entry side, i.e., the thickness d1 detected by the measuring device 5 at the entry side of the rolling stand 2 for the same section 12 of the metal strip 1. Obviously, the entry-side thickness d1 was detected in a previous cycle. However, in combination with buffer storage and path tracking, it is easy to determine in which cycle the detected entry-side thickness d1 must be used as the final entry-side thickness d1'. Therefore, in addition to the pure detection, the detection block 18 also implements a transport model that models the transport of a section 12 from the location of the detection device 5 to the rolling stand 2.

[0109] Furthermore, the current inlet velocity v1 and the current outlet velocity v2 are input to the learning block 17. These values can be, for example, measured values detected in the corresponding cycle by means of the measuring devices 6 and 8. Finally, the desired value d2* for the thickness of the metal strip 1 on the outlet side, i.e., the desired thickness d2*, is input to the learning block 17.

[0110] The block 17 learns the final thickness deviation δd2 according to the mass flow equation. In particular, the block 17 learns the final thickness deviation δd2 according to the following relationship:

[0111] (6).

[0112] The determined final thickness deviation δd2 relates to the section 12a of the metal strip 1 currently being rolled in the rolling stand 2. Figure 5 The design thus realizes the so-called mass flow control (English: mass flow control).

[0113] Figure 6 Shown Figure 5 A modified version of . Figure 6Within the scope of the modification of , the selected final thickness deviation δd2 also relates to the section 12a of the metal strip 1 currently being rolled in the rolling stand 2. Figure 6 The design thus also achieves mass flow regulation. Figure 5 The difference is that the learning block 17 is replaced by another learning block 18. The learning block 18 is implemented by the control device 9—analogously to the regulator block 17—generally as a software block based on the implementation of the control program 10.

[0114] The learning block 18 comprises a transport model 19 and a calculation block 20. With the aid of the transport model 19, the path tracing of the section 12 after passing the detection device 5 is modeled. In addition, the final entry-side thickness d1' is learned. This learning is performed by filtering a plurality of thicknesses d1 detected at the entry side of the rolling stand 2. This is in Figure 6 In the diagram, the transport model 19 implements a filter curve as a filter function. The final entry-side thickness d1 ′ is input to a calculation block 20 which—analogously to the determination block 17 —determines the final thickness deviation δd2 from the mass flow equation.

[0115] The filtering of the transport model 19 is usually a low-pass filtering, by means of which high-frequency fluctuations are filtered out. Preferably, this involves zero-phase filtering.

[0116] In accordance with Figure 7 Within the scope of the embodiment of , the final thickness deviation δd2 relates to the section 12c of the metal strip 1 which has been rolled before the current rolling section 12a of the metal strip 1. Figure 7 The design thus implements so-called feedback control.

[0117] Specifically, it is possible to provide the regulator block 15 with a corresponding Figure 7 As the final thickness deviation δd2, a value is input, which is directly and indirectly known from the measured values of the measuring device 7. In particular, the difference between the setpoint thickness d2* and the final thickness d2' on the inlet side of the rolling stand 2 can be determined in the calculation block 21 and output to the controller block 15 as the final thickness deviation δd2. As the final thickness d2', the calculation block 21 is fed with the final thickness d2' according to Figure 7 In the embodiment of , the thickness d2 detected on the discharge side for the section 12c is directly input. The calculation block 21 can also be implemented as a software block by the control device 9 based on the execution of the control program 10.

[0118] Figure 8 Shown Figure 7 A modified version of . Figure 8Within the scope of the modification of , the final thickness deviation δd2 determined relates to the section 12c of the metal strip 1 that has already been rolled in the rolling stand 2. Figure 6 Therefore, the design scheme also realizes feedback regulation. Figure 7 The difference lies in calculation block 21, which is replaced by calculation block 22 and a downstream filter block 23. In addition, a further calculation block 24 can be connected in parallel to calculation block 22. Blocks 22 and 23, and possibly also block 24, are implemented by control device 9—like the other blocks—generally as software blocks based on the execution of control program 10.

[0119] A number of temporary thickness deviations δd2' are input to the filter block 23, relating to the corresponding period. These temporary thickness deviations δd2' relate to a corresponding number of segments 12 of the metal strip 1. They indicate the corresponding deviations of the thickness d2 of the respective segment 12 of the metal strip 1 from the desired discharge-side thickness d2*. The filter block 23 determines the final thickness deviation δd2 by filtering the respectively input temporary thickness deviations δd2'. The filtering is typically a low-pass filter, which removes high-frequency fluctuations. To achieve this filtering, the filter block 23 also implements a transport model, which models the transport of the segments 12 from the rolling stand 2 to the location of the testing device 7, as well as any other transports as needed.

[0120] In a preferred embodiment, the filter corresponds to Figure 9 The view in is zero-phase filtered. This is due to Figure 9 It is indicated in this way that the sections 12 of the metal strip are marked there, whose temporary thickness deviations δd2' are input into the determination of the final thickness deviation δd2. It is indicated that, on the one hand, a plurality of temporary thickness deviations δd2' of a plurality of sections 12d are input into the determination. These sections 12d have already been rolled, but after the section 12c to which the final thickness deviation δd2 relates. Section 12a can be one of the sections 12d. These sections 12d are as follows: Figure 9 As shown in FIG, , it is generally located before the measuring device 7, that is, it has not yet passed through the measuring device 7. On the other hand, within the scope of zero-phase filtering, multiple temporary thickness deviations δd2′ are generally input into the determination of the final thickness deviation δd2. These temporary thickness deviations relate to multiple sections 12e of the metal strip 1. These sections 12e have not only been rolled, but were even rolled before the section 12c to which the final thickness deviation δd2 relates. These sections 12e are therefore generally located after the measuring device 7, that is, they have already passed through the measuring device 7. Finally, the temporary thickness deviation δd2′ of the section 12c, whose discharge-side thickness d2 has just been measured by the measuring device 7 in the corresponding cycle, is also input into the determination of the final thickness deviation δd2.

[0121] For these temporary thickness deviations δd2' of the sections 12d, no measured values for the discharge-side thickness d2 exist. Given these thickness deviations δd2', it is therefore necessary for the control device 9 to determine the corresponding temporary thickness deviations δd2' using the mass flow equation using the calculation block 22. The corresponding final entry-side thickness d1' of the respective section 12d is thus input into the determination of the corresponding temporary thickness deviations δd2'. Furthermore, the entry speed v1 and the entry speed v2 effective for the respective section 12d are input into the determination of the corresponding temporary thickness deviations δd2'. The corresponding speeds v1 and v2 are readily known to the control device 9 since these sections 12d have already been rolled.

[0122] It is possible that the respective final entry-side thickness d1' directly corresponds to the thickness d1 detected for the section 12d. It is also possible that the control device 9 - in each case for the corresponding section 12d - determines the respective final entry-side thickness d1' by filtering a plurality of thicknesses d1 detected on the entry side of the rolling stand 2. This determination can be performed in the same manner as explained above for the mass flow control (MFC).

[0123] In principle, the same procedure can be used for the temporary thickness deviation δd2' of segment 12e. In this case, calculation block 24 can be omitted. However, for multiple temporary thickness deviations δd2' of multiple segments 12e, measured values for the discharge-side thickness d2 are already available. Therefore, for these temporary thickness deviations δd2', it is possible for the control device 9 to utilize the respectively detected measured values for determining the multiple corresponding temporary thickness deviations δd2'. In particular, in the same block 24, only the difference between the corresponding measured value d2 and the discharge-side target thickness d2* must be calculated.

[0124] The segment 12 c can be processed as required, as far as the knowledge of its temporary thickness deviation δd2 is concerned, like one of the segments 12 d or one of the segments 12 e , the latter being preferred.

[0125] Figure 10 The overall structure of the control device 9 is shown again only for the adjustment of the rolling stand 2. Figure 10 The control device 9 includes three main blocks 25 to 27. The main block 25 performs FBC. The FBC can be constructed as shown above. Figures 7 to 9 As explained above, one of these designs is implemented. The main block 26 performs MFC. The MBC can be constructed in particular as described above in conjunction with Figure 5 and 6As explained, one of these design options is implemented. Main block 27 implements FFC (Feed Forward Control, English: Feed Forward Control, German: Vorsteuerung). FFC compensates for thickness errors on the inlet side. It can be designed, in particular, as explained in the aforementioned earlier European patent application 20184420.6 by Primetals Technologies Deutschland GmbH. However, other designs of FFC are also possible.

[0126] Each of the main blocks 25 to 27 receives a corresponding setpoint value. This is generally a corresponding additional setpoint value. The additional setpoint values can be superimposed on one another and, if necessary, on a basic setpoint value at a corresponding node 28. The output signal of node 28 serves as the input signal for the control device 13 or its regulation (HGC).

[0127] As already mentioned, it is possible for the control device 9 to receive multiple setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* for multiple control elements 13, 14, 3, 4. In the case of multiple setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* for multiple control elements 13, 14, 3, 4, it may be necessary to delay the individual setpoint values s*, M2*, vU*, v3*, M3*, v4*, M4* in time in order to ensure a synchronous response of the different control elements 13, 14, 3, 4. This is known and familiar to those skilled in the art and can be easily implemented. Therefore, it is not necessary to explain it in detail.

[0128] The present invention offers numerous advantages. In particular, it allows for a nearly complete calibration of both the inlet-side thickness deviation and the outlet-side thickness deviation δd2 in a simple manner. This applies particularly when not only the MFC and / or FBC are implemented in the manner and method according to the invention, but also when not only the MFC but also the FBC is implemented in the manner and method according to the invention, and in addition, the FFC is implemented as described in European Patent Application 20184420.6. Furthermore, commissioning can be accelerated.

[0129] Furthermore, it is easily possible to retrofit existing rolling mills according to the invention. Consequently, no hardware modifications are necessary, namely the rolling stand 2, the input device 3, the output device 4, the measuring devices 5 to 8, and the control device 9. Only the control program 10 for the control device 9 must be modified.

[0130] Although the present invention has been illustrated and described in detail through preferred embodiments, the present invention is not restricted to these disclosed examples and those skilled in the art may derive further variations therefrom without departing from the scope of protection of the present invention.

[0131] Reference Signs List

[0132] 1 Metal strip

[0133] 2 rolling stands

[0134] 3 Input device, control mechanism

[0135] 4 Output device, control mechanism

[0136] 5 to 8 measuring devices

[0137] 9 Control device

[0138] 10 Control Program

[0139] 11 Machine Code

[0140] 12 Sections of metal strip

[0141] 13. Adjustment device, control mechanism

[0142] 14 Driver, control mechanism

[0143] 15 regulator blocks

[0144] 16 Modify Block / Inverse Model

[0145] 17, 18 Acquisition Block

[0146] 19 Transport Module

[0147] 20, 21, 22, 24 calculation blocks

[0148] 21, 23 filter blocks

[0149] 25 to 27 Main Block

[0150] 28 nodes

[0151] d1, d2 are the detected thickness values

[0152] d1', d2' final thickness values

[0153] Steps S1 to S4

[0154] M2*, M3*, M4*, vU*, v3*, v4*, s* Rated values

[0155] S'* Temporary rating

[0156] v1 to v4, vU speed

[0157] Z internal state

[0158] δd2, δd2' thickness deviation

Claims

1. Operating method for a rolling facility, - in, An input device (3) arranged upstream of a rolling stand (2) of the rolling mill feeds a metal strip (1) to the rolling stand (2), - wherein the rolling stand (2) rolls the metal strip (1), - wherein a discharge device (4) arranged downstream of the rolling stand (2) discharges the metal strip (1), - wherein the control device (9) of the rolling plant periodically determines a corresponding number of setpoint values (M2*, M3*, M4*, vU*, v3*, v4*, s*) for a certain number of control elements (3, 4, 13, 14) based on a corresponding number of final thickness deviations (δd2) of a certain number of sections (12) of the metal strip (1) from the discharge-side setpoint thickness (d2*) of the metal strip (1), and outputs the determined setpoint values (M2*, M3*, M4*, vU*, v3*, v4*, s*) to the control elements (3, 4, 13, 14), - wherein the control mechanism (3, 4, 13, 14) comprises: the input device (3); and / or the adjustment device (13) of the rolling stand (2) for setting the rolling gap of the rolling stand (2); and / or the drive (14) of the rolling stand (2) for driving the rollers of the rolling stand (2); and / or the output device (4), - wherein the setpoint value (v3*, M3*) for the input device (3) is a setpoint speed (v3*) or a setpoint torque (M3*), the setpoint value (s*) for the adjustment device (13) is a rolling gap setpoint value (s*), the setpoint value (M2*, vU*) for the drive (14) is a roll peripheral speed (vU*) or a rolling torque (M2*), and the setpoint value (v4*, M4*) for the output device (4) is a setpoint speed (v4*) or a setpoint torque (M4*), It is characterized by: The control device (9) determines at least one of the setpoint values (M2*, M3*, M4*, vU*, v3*, v4*, s*) as a function of the amount of the final thickness deviation (δd2) while taking into account a description of the inverse frequency behavior of the corresponding control element (3, 4, 13, 14).

2. The operating method according to claim 1, characterized in that: The number of final thickness deviations (δd2) corresponding to the cycle is equal to 1, and the control device (9) obtains the final thickness deviation (δd2) according to the final entry side thickness (d1') of the section (12) of the metal strip (1) according to the mass flow equation, taking into account the entry speed (v1) of the section (12) of the metal strip (1) into the rolling stand (2) and the discharge speed (v2) of the section (12) of the metal strip (1) from the rolling stand (2), and the section (12) of the metal strip (1) to which the obtained final thickness deviation (δd2) relates is the current rolling section (12a) of the metal strip (1).

3. The operating method according to claim 2, characterized in that: The final entry side thickness (d1') of the section (12) of the metal strip (1) is the thickness (d1) of the section (12) of the metal strip (1) detected at the entry side of the rolling stand (2) for the current rolling section (12a) of the metal strip (1) before the corresponding cycle, or the control device (9) obtains the final entry side thickness (d1') of the section (12) of the metal strip (1) by filtering the thickness (d1) detected at the entry side of the rolling stand (2) for a plurality of sections (12) of the metal strip (1).

4. The operating method according to claim 1, characterized in that: The number of final thickness deviations (δd2) corresponding to the cycle is equal to 1, and the final thickness deviations (δd2) relate to a section (12c) of the metal strip (1) rolled before a currently rolled section (12a) of the metal strip (1).

5. The operating method according to claim 4, characterized in that: A measuring device (7) arranged between the rolling stand (2) and the discharge device (4) detects the discharge side thickness (d2) of the section (12c) of the metal strip (1) and inputs it to the control device (9), and the final thickness deviation (δd2) is obtained based on the detected discharge side thickness (d2) and the discharge side target thickness (d2*).

6. The operating method according to claim 4, characterized in that: The control device (9) determines the final thickness deviation (δd2) by filtering a corresponding number of temporary thickness deviations (δd2') of a plurality of sections (12) of the metal strip (1) from the discharge-side target thickness (d2*).

7. The operating method according to claim 6, characterized in that: The filtering is a zero-phase filtering, the first part of the temporary thickness deviation (δd2') relates to the following sections (12d) of the metal strip (1), which, although already rolled, are rolled after the section (12c) of the metal strip (1) to which the final thickness deviation (δd2) relates, and the control device (9) determines the temporary thickness deviation (δd2') according to the mass flow equation based on the corresponding consistent final entry side thickness (d1') of the metal strip (1) and taking into account the entry speed (v1) of the corresponding section (12) of the metal strip (1) into the rolling stand (2) and the discharge speed (v2) of the corresponding section (12) of the metal strip (1) from the rolling stand (2).

8. The operating method according to claim 7, characterized in that: For the first part of the temporary thickness deviation (δd2), the corresponding final entry side thickness (d1') of the segment (12) of the metal strip (1) is the thickness (d1) of the corresponding segment (12) of the metal strip (1) detected at the entry side of the rolling stand (2) for the corresponding segment (12) of the metal strip (1), or the control device (9) obtains the corresponding final entry side thickness (d1') of the corresponding segment (12) of the metal strip (1) by filtering the thicknesses (d1) detected at the entry side of the rolling stand (2) for multiple corresponding segments (12) of the metal strip (1).

9. The operating method according to claim 7 or 8, characterized in that: A measuring device (7) arranged between the rolling stand (2) and the output device (4) detects the discharge side thickness (d2) for multiple sections (12) of the metal strip (1) and inputs it to the control device (9), the second part of the temporary thickness deviation (δd2') relates to the following sections (12) of the metal strip (1), which are rolled before the section (12c) of the metal strip (1) to which the final thickness deviation (δd2) relates, and the control device (9) obtains the corresponding temporary thickness deviation (δd2') for the second part of the temporary thickness deviation (δd2') based on the respectively detected discharge side thickness (d2) and the discharge side target thickness (d2*).

10. The operating method according to any one of the preceding claims, characterized in that - prescribing a description of the inverse frequency behavior of the corresponding control mechanism (3, 4, 13, 14) of the control device (9) by means of a corresponding inverse model (16); - the control device (9) inputs the final thickness deviation (δd2) of a section (12) of the metal strip (1) into the corresponding inverse model (16); and - The control device (9) uses the input final thickness deviation (δd2) with the aid of the corresponding inverse model (16) to track the corresponding internal state (Z) of the corresponding inverse model (16) on the one hand and to determine the corresponding setpoint values (M2*, M3*, M4*, vU*, v3*, v4*, s*) on the other hand.

11. A control program comprising a machine code (11) which can be processed by a control device (9) for a rolling mill, wherein: The machine code (11) is processed by the control device (9), which operates the rolling mill according to the operating method according to one of the preceding claims.

12. A control device for a rolling mill, wherein: The control device is coded with a control program (10) according to claim 11, so that the control device operates the rolling mill according to the operating method according to any one of claims 1 to 10.

13. Rolling facilities for rolling metal strip (1), - in, The rolling mill comprises at least one rolling stand (2), an input device (3) arranged upstream of the rolling stand (2), an output device (4) arranged downstream of the rolling stand (2), and a control device (9). - wherein the input device (3) inputs the metal strip (1) into the rolling stand (2), - wherein the rolling stand (2) rolls the metal strip (1), - wherein the discharge device (4) discharges the metal strip (1) from the rolling stand (2), - wherein the control device (9) operates the rolling mill according to the operating method according to any one of claims 1 to 10.

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