WO2011038965A1 - Method for the model-based determination of actuator nominal values for the asymmetric actuators of the roll stands of a hot wide strip mill - Google Patents

Abstract

The invention relates to a design for the model-based determination of actuator nominal values for a hot wide strip mill comprising a plurality of roll stands, by which means the application of the actuator nominal values enables the adjustment of a desired target contour of the roll gaps of the stands. In a first method step, a nominal speed conicity of the hot strip is defined after each stand. In the second step, values for the strip thickness contours at the outlets of the stands are determined by means of strip flatness models. In the third step, roll separating force distributions to be applied for each stand are distributed by means of material flow models. In the fourth step, the target contour for the strip advancement actuators is determined, while in the fifth step, the actuator nominal values are calculated, for each stand, from the target contour by means of an optimising method.

Description

description

Method for the model-based determination of actuator setpoints for the asymmetric actuators of the rolling mills of a hot strip mill

The invention relates to a concept for a model-based stripline control for a hot strip mill, in particular a finishing train.

A hot strip mill, in particular a finishing train, comprises a plurality of rolling stands Gi, G2, G3,... G _{n, which are} to be rolled, typically a metal strip such as a steel, aluminum, copper or generally a non-ferrous metal strip , wherein it can be achieved by means of conventional control methods that the rolled strip has a desired final temperature and a desired final thickness. Other relevant parameters for assessing the rolling quality are, for example, the profile, the contour and the flatness of the strip. In this context, the

 DE 102 11 623 AI to name, in which some of the relevant basic concepts are described in more detail. The most important terms are redefined here. The "band profile" or the "profile value" of the band indicates the deviation of the band thickness at the band edges from the band thickness in the band center. The term "tape thickness contour" is understood to mean the strip thickness profile over the strip width minus the strip thickness in the middle of the strip. The strip thickness contour can be split into one with respect to the center of the strip symmetrical and one asymmetric portion. The asymmetric component is called "tape thickness wedge". The term "flatness" is used synonymously with the internal stresses prevailing in the strip, regardless of whether or not these internal stresses lead to visible distortions of the metal strip.

The strip is always seen relative to a rolling road center line in each of the rolling stands G ± (i = l, ..., n) with a be knew each center offset with respect to the frame center (at z = 0) and threaded with a known respective inlet side strip thickness wedging, so that the band or the head of the strip from the respective rolling stand with the respective center offset, a respective outlet side strip thickness wedge and a expires respective outlet side band curvature.

When rolling a belt, internal stresses can be "rolled in" into the belt. Depending on the strip thickness, the band width, the material properties of the strip and the possibly acting on the strip outer tensile stresses cause these internal stresses to more or less pronounced band deformations such as. Wave or saber formation. One of the major causes of "rolling in" intrinsic stresses in a rolling stand is a non-negligible band-thickness wedging of the belt entering the skeleton. The strip thickness wedging can have various causes. For example, the strip may already have a wedge-shaped strip thickness contour prior to rolling. Alternatively, the strip thickness taper may have been caused by rolling in the nip of an upstream stand. For stamping a strip thickness wedge into the strip during material conversion in a rolling stand, several causes are possible. For example, the tape may have a temperature gradient across the tape, the tape may enter the nip off-center, or the nip itself may be wedge-shaped. Also combinations of these (and other) causes are possible.

Thus, if a hot strip with a non-vanishing strip thickness and / or off-center enters a stand G ±, the strip shape in the following intermediate stand section between the stands G ± and Gi ₊ i will generally not be straight but saber-shaped. The saber-shaped course depends on whether the band is clamped on only one side in a scaffold (when threading in or out of the scaffold) or on both sides of two successive scaffolds (when rolling the main part of the tape, ie with the exception of tape head and tape foot). The influence of the strip tension on the saber shape and thus on the strip run and the strip position, ie in particular the deviation of the strip layer from the middle layer, is clearly understandable: Considering a strip edge of a belt G emerging from a gantry and assuming that the rate of plastic material flow at this band edge is less than that at the other band edge, it is clear that the ribbon will be inhomogeneous across the band as soon as the next frame Gi ₊ i intervenes. In particular, the strip tension is higher on the considered "shorter" strip edge. The higher strip tension causes a greater decrease in the thickness of the strip at this strip edge and thus an increase in the speed of the plastic material flow at this edge. The velocity wedge of the plastic material flow over the bandwidth is reduced; the inter-frame stresses have a stabilizing effect on the strip run within the finishing train.

For the stripline control actuators are used on the individual stands G ± the rolling mill, which influence the shape of the roll gap - and thus the strip thickness profile - asymmetrically over the bandwidth with respect to the center of the frame or the center of the belt. Such actuators are, for example, pivoting and asymmetric bending forces. Furthermore, symmetrical actuators are provided, for example. Symmetrical bending forces, means for the axial displacement of so-called. CVC work rolls (rolls with S-shaped cut) and / or so-called. "Pair crossing". These symmetrical actuators are used for profile and flatness control. An automatic, model-based method or a device for profile and flatness control is disclosed in DE 102 11 623 AI. In the prior art, for example, it is also known that a helmsman of the rolling train when threading the tape tracked the tape head visually and - according to his personal impression of tape position and tape waviness - the employment of the tape head straight through rolling mill (in particular a pivoting position of the rollers) sets.

It is the object of the present invention to provide a control method and a control device for a stripline control of a rolling mill having a plurality of stands, in particular a hot strip mill or finishing train.

This object is achieved by the inventions specified in the independent claims. Advantageous embodiments emerge from the dependent claims.

In the solution according to the invention, a concept of a complete, model-based control method for the stripline control of the rolling train is given. A method is presented that can be used to calculate the setpoint values of the asymmetrical rolling stand actuators for the stripline control. According to the invention, an iterative method is proposed for model-based determination of actuator setpoints for the asymmetric actuators of a hot strip mill having multiple stands G ± with i = 1, ..., n and n> 2 for rolling a hot strip, each stand G ± one roll - Has gap with a roll gap contour and the actuators act on rollers of the stands so that for each frame Gi between the rollers a certain target contour Ki (z; k) of the roll gap is adjustable. The process is an iterative process, which has five individual steps per process cycle:

1) In a first step, a Soll¬

Velocity wedging (v (k)) after each gantry G ±.

2) In a second step, values for strip thickness contours θ _; (z; k) at the outlets of the frameworks G ±

i = l, ..., nl, where 2.1) first with the aid of band flatness models for each gantry Gi a speed profile (v _; (z; k)) is calculated at the respective outlet of the gantry G ±, each gantry G ± its own band flatness model is assigned and wherein in the band flatness Model a strip thickness contour Θ _Η (z; k) of the hot strip at the inlet and a strip thickness contour Θ; (z; k) of the hot strip at the outlet of the respective framework G ± are taken into account,

2.2) then the parameters contained in the calculated velocity profiles (v _; (z; k))

 Speed wedges (v 'fk)) are compared with the desired speed wedges fk)) specified in the first step,

2.3) the band thickness contours 0 _j (z; k) to 6 (z; k) are modified if the calculated

 Velocity discontinuities (v 'fk)) not in a tolerance range around the target speed wedges

(· ^ ₀ "(k)) and the second step is executed again or

2.4) to the third step, if the calculated speed wedges (v '(k)) in the tolerance range around the desired speed wedges

 (ν «" (k)). 3) In a third step, G ± applied rolling force distributions f ± (z; k) are determined for each framework by means of material flow models, whereby each framework G ± is assigned a material flow model. 4) In a fourth step, the target contour Ki (z; k) is determined for the tape drive actuators, wherein

 4.1) is first calculated from the rolling force distributions f ± (z; k) for each framework Gi by means of a work roll flattening model a flattening Ai (z, k) of the rolls in the framework G ±

4.2) for each framework G ± a residual strip thickness profile 6 _; (z; k) - Ai (z; k) is calculated by calculating the flattening A ± (z; k) from the respective strip diameter determined in the second step. cam contour G _j (z; k) at the outlet of the gantry G ± is subtracted,

 4.3) for each framework G ± the target contour Ki (z; k) is calculated

 is hidden by a symmetrical portion of the residual band thickness profile, wherein the target contour Ki (z; k) corresponds to the remaining proportion of the residual strip thickness profile.

5) In a fifth step, finally, for each gantry Gi with the aid of an optimization method, the actuator setpoint values are calculated from the target contour Ki (z; k).

Advantageously, in the first step, first

an eccentricity d ± -i of the hot strip (10) before each gantry Gi and the eccentricity d _{n of} the hot strip (10) after the last gantry G _n ,

the band thickness contour θ _η (z; k) is measured after the last framework G _n ,

- Determines the band thickness contour θ ₀ (z; k) before the first frame Gi, in particular by measurement or estimation.

The setpoint speed _{wedges v.sub.10} (k) to be specified are determined in a control loop from the setpoint

Velocity discontinuities v ^ _oll (k-1) and the eccentricity measurements d ± -i (kl) and di (kl) of the preceding process cycle k-1 and the external measurement values di-i (k) and d ± (k ).

In the second step, the following data is supplied to the band flatness model assigned to the framework G ±:

 - an external measurement value d ± (k) at the inlet of the framework G ±,

 - band thickness contours 9 ± _i (z; k) and 9 ± (z; k) at the inlet and outlet of the gantry G ±,

 - belt tension at the inlet and outlet of the gantry G ±,

- velocity profile ν _Η (z; k) at the inlet of the framework G ±,

- measured rolling force f ± (k) in the framework G ±, - nominal values for the belt width, entrance thickness in the center of the belt and decrease of the hot strip (10) in the gantry G ±.

In the third step, the same data is fed to the material flow models as the band flatness models. Additionally serve as input variables of the material flow models friction parameters R serve, which describe the friction conditions in the longitudinal and transverse direction in the nip. In the fourth step, following the sub-step

4.2) first from the residual strip thickness profile θ _; (z; k) -Δι (z; k) additional correction values a ± (z; k), b ± (z; k), c ± (z; k) are deducted. Where:

 a ± (z; k) an initial contour of the work rolls,

- b ± (z; k) a currently calculated thermal and wear crown and

 - c ± (z; k) a contour of the symmetrical profile and planarity actuators of the framework G ±.

 In sub-step 4.3), the thus corrected residual strip thickness profile is subsequently used to determine the target contour Ki (z; k).

Furthermore, a computer program product according to the invention for carrying out the method according to the invention is proposed as well as a control computer programmed for the computer program product for a rolling train with at least two rolling stands G ±.

Compared with a non-model-based tape control, the inventive solution bpsw. the advantages that, after successful piloting of a plant for downstream plants, shorter commissioning and service times are required and that a better extrapolability to a new product range is possible.

Further advantages, features and details of the invention will become apparent from the embodiment described below and with reference to the drawings. Showing:

Figure 1 is a schematic representation of a mehrgerüstigen

 Rolling street

Figure 2 is a schematic representation of the rolling mill for

 Illustrating the second process step, Figure 3 is a schematic representation of the rolling mill for

 Illustrating the third method step, Figure 4 is a schematic representation of the rolling mill for

 Illustrating the fourth method step, Figure 5 is a schematic representation of the rolling mill for

 Illustration of the fifth method step.

In the figures, identical or corresponding areas, components, component groups or method steps are identified by the same reference numerals.

FIG. 1 shows a side view or a section of a rolling train 1 with a belt 10 to be rolled there and a plurality of rolling stands G ± (i = 1, 2,... N). In the example shown, the rolling train should have n stands, of which only the first two stands Gi, G ₂ and the last two stands G _n -i and G _n are shown.

According to FIG. 1, a rolling train 1 for rolling a metal strip 10 is controlled by a control computer 2. The mode of operation of the control computer 2 is determined by a computer program product 2 ', with which the control computer 2 is programmed.

The following is based on a Cartesian coordinate system, wherein the x-axis of the coordinate system corresponds to the running direction of the belt 10, the y-axis indicates the belt thickness direction and the z-axis in the direction across the belt 10 and in the direction of the longitudinal axes of the rollers 21 _± the frameworks G ± is oriented. The center of the roll or frame is at z = 0. The belt 10 is in the rolling mill 1 in a Rolling direction x rolled. Each gantry G ± has at least work rolls 21i and possibly (in FIG. 1 but not shown) also support rolls. From the control computer 2 are scaffold controllers 30 ±, wherein each scaffolding Gi a scaffold controller 30 ± is provided setpoints for only indicated in Figure 1 asymmetric actuators 22i or "actuators" specified, which ultimately act on the rollers 21i and so the desired target shape or To realize the contour of the respective roll gap. The frame controllers 30 ± regulate the actuators 22 _± according to the specified setpoints. The basic interaction between the actuators 22i or actuators, the rollers and the resulting nip can be assumed to be known.

The nominal values for each rolling stand G ± influence an outlet-saprificed nip course which is established between the work rolls 21i - in interaction with the metal strip located between the work rolls. The outlet-side roll gap course corresponds to a run-out contour of the strip 10. The setpoint values for the actuators 22 _± must therefore be determined in such a way that the roll gap curve, which corresponds to the desired outlet-soaping strip thickness contour, results.

In order to determine the setpoint values for the actuators 22 ±, input variables are supplied to the control computer 2, which are explained below in connection with the five individual steps 1) to 5) of the method according to the invention. The control calculator 2 thus determines the setpoint values from the input variables supplied to it.

The strip thickness contour θ (ζ) which, depending on the position z, indicates the thickness of the strip 10, ie its extension in the y direction minus the strip center thickness, can be approximately approximated by a second degree polynomial, with the exception of the strip edges:

The coefficient Θ describes the wedging of the band 10 or the band thickness contour.

Furthermore, the band thickness contour at the inlet of the gantry G ± with θι_ι (ζ) and at the outlet of the gantry G ± with θ ± (ζ) (with l <i <n). At the outlet of a gantry G ± the plastic material flow of the belt 10 in the rolling or belt running direction exhibits a certain speed profile v ± (z) over the belt width z, which (neglecting the mean belt speed in the rolling direction) is replaced by a polynomial without a constant term can be roximated: ν,. (ζ) = ν _Ι ⁰⁾ · ζ + ν _Ι ί ²⁾ · ζ ² + Ο (ζ ³ ) (Eq.

The coefficient v- describes a speed wedge or a material flow wedging, which leads to the initially described saber formation of the band 10, while the coefficient vi ^{2) is} a measure of the flatness or unevenness of the band 10. Here, vi ²⁾ > 0 edge waves, while vi ²⁾ <0 means center waves.

Furthermore, let a deviation of the center of the strip in the z-direction from the center of the roll or frame at z = 0 immediately before a frame i be denoted by d ± -i. A calculation cycle k of the iterative method according to the invention has five individual steps 1) to 5), which are executed, for example, with the aid of a computer program on the control computer 2 (in the figures, the parameters "k" and "z" used hereinafter are for the sake of clarity not listed) : Step 1)

Measurements or measured value evaluation and setpoint specification for the material flow wedging v (see FIG.

Measured by means of appropriate sensors or

Transducer (not shown)

- the eccentricity d ± -i of the band 10 before each gantry G ± (with i = l, ..., n) and the eccentricity d _{n of} the band after the last gantry G _n and

the band thickness contour θ _η (z) after the last framework G _n .

The eccentricity d ± _i of the strip 10 before each gantry G ± is preferably measured optically, for example by means of a laser or camera system. For the measurement of the eccentricity d _{n of} the strip after the last stand G _n no additional measuring device is required, because this size can be determined by means of the (usually traversing) strip thickness contour measuring device after the last stand.

In addition, the band thickness contour θο (ζ) in front of the first gantry Gi is either measured online or estimates are used for θο (ζ), which are based, for example, on isolated offline or hand measurements.

In each cycle k, in the calculation step 1 of the tape running control algorithm implemented in the computer program, a (new) desired speed _{discontinuity v.sub.roll} (k) is set after each framework Gi (with i = 1,..., N). The target Geschwindigkeitskeiligkeiten vf] _oU (k) (i = l, ..., n) are in a control loop is calculated from the target Geschwindigkeitskeiligkeiten v ^ _oll and Außermittig- keits metrics di_i (kl) and di (kl ) of the last one

Rechenzyklusses and the current Außermittigkeits- measured values d ± _i (k) and di (k).

For the first cycle (k = 1), the values which are still used can be used as "start values" vf] _oU (0), di_i (0) and di (0), for example from the rolling process of a previously rolled strip are known. Alternatively, v (0) = di_i (0) = d ± (0) = p could also be assumed, where p can be any numerical value including p = 0.

Step 2)

Calculation of setpoint values for the intermediate frame strip thickness contours 0i (z; k), in particular for the strip thickness wedging after each stand G ± (see FIG.

Here, suitable setpoint values for the strip thickness contours 0i (z; k), i = 1,..., N-1, at the outlets of the stands G ±, i = 1,..., N-1, are calculated. With the aid of a physical band-plane model 40 ± (or an approximation function

("Look-up table") of a band flatness model) for each framework G ± the velocity profiles v ± (z) including the coefficients v (k) (see Eq

Velocity equations, calculated at the effluents of the frameworks G ±, where each framework G ± is assigned a model 40 ±. Models 40 ± as well as other models used below are implemented in the computer program. The model 40 ± is an extension of the model described in DE 102 11 623 A1 and designated there as "flatness estimator" or its approximation function with additional consideration of asymmetric effects.

The model 40 ± associated with framework G ± is supplied with the following data:

 - external measurement values d ± (k) at the inlet of the framework G ±,

assumed, calculated or measured strip thickness contours 0i_i (z; k) and 9 ± (z; k) at the inlet and outlet of the gantry G ±,

- assumed, calculated or measured strip tension at the inlet and outlet of the gantry G ±, - assumed or calculated velocity profile v _± _i (z; k) at the inlet of the framework G ±,

 - measured rolling force in the framework G ±,

 - Calculation or setpoint values for bandwidth, entrance thickness (in the middle of the tape) and decrease in the framework G ±.

The velocity profile v ₀ (z) applied to the band flatness model 40i of the first gantry Gi can not normally be measured and is assumed to be v ₀ (z) = 0.

By means of the models 40 ± and the input data mentioned above, in each cycle k in step 2, the velocity profiles Vi (z; k) at the outlets of the stands G ± are calculated. The speed wedges contained herein are compared in a logic unit 41 with the desired speed wedges determined in step 1).

In the event that this comparison shows that the computation values for the velocity profiles Vi (z; k) are not within a tolerance range, ie between a maximum and a minimum value, around these nominal values, the band thickness contours θι (ζ) to 0 _n -i (z; k) is modified until the comparison gives a sufficient match. In the event that the comparison reveals that the calculated values for the velocity profiles v ± (z; k) are actually within the tolerance range around the target values, the method goes to step 3), where the band thickness contours determined in the context of the described comparison 9 ± ( z; k) continue to be used.

Step 3)

Calculation of the rolling force distribution f ± over the bandwidth for each framework G ± (see Figure 3):

Each framework G ± is a physical material flow model 50i (or a look-up table) of a such material flow model) to which the same data as the model 40 ± in step 2) are supplied. In addition, the material flow model 50 ± receives as input variables from a unit 51 friction parameters R, which describe the different friction conditions in the longitudinal and transverse direction in the roll gap.

The friction parameters R are model adaptation parameters that are determined so that the overall algorithm predicts the measured strip thickness contour and the measured strip flatness after the last stand as well as possible.

The material flow models 50 ± model the physical behavior of the belt 10 in the nip of the gantry G ±.

As in step 2), the velocity profile in front of the first skeleton vo (z) = 0 is also assumed here.

The material flow models 50 ± are used to determine the rolling force distributions fi (z; k) based on the above input data. The respective material flow model 50i determines for a gantry G ± the line load distribution f ± (z) between strip and work rolls. The integral of f ± (z) over the bandwidth gives the rolling force in the framework G ±.

The main uncertainty in the modeling of the material flow in the roll gap lies in the friction conditions in the roll gap, both in the rolling direction and transverse to the rolling direction. The friction parameters R are therefore the main Model1 adaptation parameters.

Step 4)

Calculation of the target contour for the stripline actuators 22 _± (ie, the asymmetric strip thickness contour actuators) for each framework G ± (see Figure 4): FIG. 4 shows the further processing of the rolling force distributions fi (z; k) determined in step 3) of the cycle k. These rolling force distributions are supplied for each framework G ± a computing unit 70 associated with the stand G ± in which the flattening Ai (z, k) of the work rolls in the framework G ± connected to the rolling force distributions f ± (z) is determined by means of a work roll flattening model 71 is calculated.

This flattening Ai (z; k) is subtracted from the strip thickness contour 9 ± (z; k) at the outlet of the stand G ± in a subtracter 72, ie in the subtracter 72 _± a residual strip thickness profile θ ± (z; k ) -Δι (z; k). From this residual band thickness profile, 73 ± 75 ± correction values a ± (z; k), b ± (z; k), c ± (z; k) can be subtracted in further subtractors, where a ± (z; k) the initial contour of the work rolls (ie, the finish), b ± (z; k) represents the current calculated thermal and wear crown, and c ± (z; k) describes the contour of the symmetrical profile and planarity actuators of the stand Gi. When calculating the quantities a ± (z; k), b ± (z; k) and Ci (z; k), the current eccentricity d ± (k) of the band is taken into account.

Eventually, this will be the last subtractor 75 ±

Removable, corrected residual strip thickness profile of a logic unit 76 ± supplied in which the symmetrical portion of the residual band thickness contour is hidden. The remaining band thickness contour is the target contour Ki (z; k) to be adjusted by means of the band-winder actuators 22 ± of the gantry G ±. The arithmetic unit 70 ± thus ultimately supplies this target contour K _± (z; k).

Step 5)

Calculation of the setpoint values for the stripline actuators 22 _± (see Figure 5):

In a last step, for each framework G, for example with the aid of a so-called "least squares" optimization 100 (method of least squares) from the target contour Ki (z; k), taking into account the physical physical actuator limitations lim of the stripline actuators 22 _± calculates the correct actuator values, ultimately adjusting the stripline actuators 22 _{± of} the stand G ±. Possibly.

Corrections corr, eg manual, can be added to the setup.

In the event that for a scaffold several independent

Tape running actuators are present, for example. Panning and asymmetric bending, can in the optimization step

Step 5 the optimal combination of these actuators are determined.

Claims

claims 1. Iterative method for model-based determination of actuator setpoints for asymmetric actuators (22 ±) of a hot strip mill having a plurality of stands G ± with i = 1, ..., n and n> 2 for rolling a hot strip (10), each rolling gel , A method for model-based determination of actuator setpoints for asymmetric actuators (22 ±) of a hot strip mill having a plurality of stands G ± with i = 1, ..., n and n> 2 for rolling a hot strip (10), each stand G ± one Rolling gap having a roll gap contour and the actuators (22 ±) act on rollers (21 ±) of the stands, that for each framework G ± between the rollers (21 ±) a certain target contour Ki (z; k) of the roll gap is adjustable . when in a process cycle k (k = 1, 2, ...): 1) in a first step, a desired speed wedging (- ¹ ^, (k)) is given after each framework Gi,  2) in a second step values for strip thickness contours 6 _; (z; k) at the outlets of the scaffolds G ±, i = l, ..., nl, where 2.1) is first calculated by means of flat-slab models 40 ± for each gantry G ± a velocity profile (v _; (z; k)) at the respective gantry outlet G ±, with each gantry G ± having a band flatness model 40 ± and wherein in the band flatness model 40 ± a band thickness contour 0 (z; k) of the hot band (10) at the inlet and a band thickness contour 0 _; (z; k) of the hot strip (10) are taken into account at the outlet of the respective stand G ± 2.2) then the parameters contained in the calculated velocity profiles (v _; (z; k))  Velocities (v 'fk)) with the predetermined speed wedges specified in the first step (· ^ ₀ "(k)) are compared, 2.3) the band thickness contours 0 _j (z; k) to 6 (z; k) are modified if the calculated Velocities {v (k)) are not within a tolerance range around the setpoint Speed discontinuities (vi ^ fk)) and the second step is repeated or 2.4) moves to the third step if the calculated speed wedges (v 'fk)) are in the tolerance range around the desired speed wedges (

(k)),  3) in a third step with the aid of material flow models 50 ± for each gantry G ± to be applied rolling force distributions fi (z; k), wherein each gantry Gi is assigned a material flow model 50 ± 4) in a fourth step, the target contour Ki (z; k) is determined for the tape drive actuators (22i), wherein 4.1) is first calculated from the rolling force distributions fi (z; k) for each framework Gi by means of a work roll flattening model (71) a flattening A ± (z, k) of the rolls in the framework G ± 4.2) for each framework G ± a residual strip thickness profile 6 _; (z; k) - Ai (z; k) is calculated by calculating the flattening A _± (z; k) from the respective strip thickness contour θ determined in the second step _; (z; k) at the outlet of the framework G ± is subtracted,  4.3) for each gantry G ± the target contour Ki (z; k) is calculated by hiding a symmetrical portion of the residual strip thickness profile, the target contour Ki (z; k) corresponding to the remaining portion of the residual strip thickness profile,  5) in a fifth step for each framework G ± with the aid of an optimization method, the actuator setpoint values from the target contour Ki (z; k) are calculated. 2. The method according to claim 1, characterized in that in the first step first - an eccentricity d ± -i of the hot strip (10) before each gantry Gi and the eccentricity d _{n of} the hot strip (10) after the last gantry G _{n is} measured, the band thickness contour θ _η (z; k) is measured after the last framework G _n , - the band thickness contour θ ₀ (z; k) is determined before the first gantry Gi is calculated, in particular by measurement or estimation, and the predetermined speed wedges ^v ? Lu (k) i ⁿ be calculated in a control loop - The desired speed _wedges v ^ _oll (k-1) and the  Off-center measurements di-i (k-l) and di (k-l) of the previous method cycle k-1 as well - the external measurement values d ± _i (k) and d ± (k) from the current cycle k. 3. The method according to claim 2, characterized in that in the second step to the framework G ± associated Bandplanheits- model 40 ± the following data are supplied:  an external measurement value d ± (k) at the inlet of the framework Gi,  - band thickness contours 9 ± _i (z; k) and 9 ± (z; k) at the inlet and outlet of the gantry G ±, - belt tension at the inlet and outlet of the gantry G ±, - velocity profile ν _Η (z; k) at the inlet of the framework G ±, - measured rolling force f ± (k) in the framework G ±,  - nominal values for the belt width, entrance thickness in the center of the belt and decrease of the hot strip (10) in the gantry G ±. 4. The method according to claim 3, characterized in that the material flow models 50 ± in the third step, the same data are supplied as the band flatness model 40 ±, and in addition as input variables of the material flow models 50 ± friction parameters R serve the friction conditions describe in longitudinal and transverse direction in the nip. 5. The method according to any one of the preceding claims, characterized in that in the fourth step following the sub-step 4.2) first of the residual band thickness profile 6 _j (z; k) - A _± (z; k) additional correction values a ± (z; k), b ± (z; k), c ± (z; k) are subtracted, where - a ± (z; k) represents an initial contour of the work rolls,  - bi (z; k) represents a currently calculated thermal and wear crown and Ci (z; k) describes a contour of the symmetrical profile and flatness actuators of the framework G ± and wherein subsequently in sub-step 4.3) the thus corrected residual strip thickness profile is used to determine the target contour Ki (z; k). 6. Computer program product for carrying out a method according to one of claims 1 to 5. 7. With a computer program product (2 ') according to claim 6 programmed control computer (2) for a rolling mill (1) with at least two rolling stands G ±. 8. controlled by a control computer (2) according to claim 7 rolling street (1).