EP3544751A1

EP3544751A1 - Strip position control with force-limited adjustment of lateral guides for the metal strip and correction of the roll adjustment

Info

Publication number: EP3544751A1
Application number: EP17816453.9A
Authority: EP
Inventors: Ilhom Gafur; Mirko TUNK
Original assignee: Primetals Technologies Germany GmbH
Current assignee: Primetals Technologies Germany GmbH
Priority date: 2016-11-24
Filing date: 2017-11-06
Publication date: 2019-10-02
Anticipated expiration: 2037-11-06
Also published as: WO2018095717A1; EP3544751B1

Abstract

A metal strip (1) comprising a strip head (7) is rolled on a rolling mill. The rolling mill comprises at least one front roll stand (2a) and one rear roll stand (2b) arranged downstream of the front roll stand (2a). Between the two roll stands (2a, 2b), the rolling mill further comprises lateral guides (8, 8') for the metal strip (1). The lateral guides (8, 8') are operated with force limitation. During the period between the exiting of the strip head (7) from the front roll stand (2a) and the entry of the strip head (7) into the rear roll stand (2b), an amount of deviation (δy) of the lateral position (y) of the strip head (7) from a setpoint position (y*) is measured by means of the lateral guides (8, 8'). A control command (S) for the front roll stand (2a) is worked out by a strip position controller (13). The front roll stand (2a) of the strip position controller (13) is controlled on the basis of the control command (S). The strip position controller (13) works out the control command (S) using the time derivative of the deviation (δy) of the lateral position (y) of the strip head (7) from the setpoint position (y*) in such a way as to counteract a change in the deviation (δy) of the lateral position (y) of the strip head (7) from the setpoint position (y*).

Description

description

Description of the Invention Banding control with force-limited adjustment of side guides to the metal band and correction of the roll adjustment

Field of engineering

The present invention is based on an operating method for a rolling train in which a metal strip is rolled,

wherein the rolling train has at least one front rolling stand and one rear rolling stand arranged downstream of the front rolling stand and furthermore has side guides for the metal strip between the two rolling stands,

- whereby the side guides are operated with power limitation,

- during the period between the expiry of the

Tape head from the front roll stand and the shrinkage of the tape head in the rear roll stand by means of the side guides a deviation of the lateral position of the tape head is quantitatively detected by a target position,

wherein a positioning command for the front roll stand is determined by means of a strip position controller,

- The front rolling stand is acted upon by the band position controller according to the determined control command.

The present invention is further based on a computer program comprising machine code executable by a rolling mill controller, wherein the processing of the machine code by the controller causes the controller to operate the mill train according to such an operating method. The present invention is further based on a control device for a rolling train, wherein the control device is programmed with such a computer program, such that the controller operates the mill train according to such an operating method.

The present invention is further based on a rolling line for rolling a metal strip, which has a tape head,

- The rolling mill having such a control device which operates the rolling mill according to such an operating method.

State of the art

Such an operating method, the corresponding computer program, the control device and the rolling train are known for example from WO 2006/119 984 AI.

From WO 2006/119 984 Al it is known to roll a slab in a roughing stand. Powerful side guides are arranged both in front of and behind the roughing stand. By means of the arrangement of WO 2006/119 984 A1, the geometry of a pre-strip should be specifically influenced in order to produce a straight pre-strip without thickness wedge and without lateral curvature. The controls of the side guides and the roughing stand are linked together in such a way that a saber or wedge slab is transformed into a straight and wedge-free sliver. The side guides are held in place with great force and only deflect when needed to protect the side guides and / or the scaffold from damage. The corresponding position of the side guides is recorded quantitatively. The nip in the roughing mill is controlled in dependence of different sizes so that it remains parallel. It is known from DE 10 2004 043 790 A1 to arrange side guides in front of and / or behind a roll stand and to detect the lateral position of the side guides and / or forces exerted by the metal strip on the side guides. Depending on the values recorded, the geometry of the roll gap is changed in order to avoid a saber and / or a wedge.

When rolling metal strip in a hot strip finishing mill, the metal strip should, if possible, be guided through the individual rolling stands of the rolling mill with the highest level of running stability and optimal flatness results. For this purpose, it is particularly desirable to guide the metal strip centrally and straight through the individual rolling stands of the rolling train. This also applies and in particular in the Einfädelphase of the metal strip, so if the beginning of the metal strip (= tape head) has already leaked out of one of the rolling stands and strives for the next rolling stand. If an asymmetric deformation takes place in the rolling stand in the threading phase (ie if the metal strip is subjected to a thickness wedge), the metal strip does not run straight but in a circular arc (also called a saber in professional circles) towards the next rolling stand. The metal strip therefore meets off-center in the downstream rolling mill. This in turn has an asymmetric reduction in the downstream rolling stand. The metal strip can therefore run out of the downstream rolling stand again with a saber. The saber can be directed in the same direction as before or in the opposite direction.

To limit the lateral emigration of the metal strip side guides are provided. The side guides are operated position-controlled in the prior art. If the lateral position of the metal strip has only a slight deviation from the desired position, the metal strip does not contact the side guides. Otherwise, sideways migration will result from one-sided grinding at one of the two sides. Guided limits or plays serpentine within the two side guides. A one-sided grinding damages the band edges. A serpentine walking leads due to the uncontrolled lateral belt movement to an off-center puncture in the downstream rolling mill and thus to flatness errors. In extreme cases, the tape head can completely miss the nip of the following rolling mill stand or doubled into the nip of the following rolling mill. This applies in particular to the rear rolling stands of a multi-stand finishing train, that is, if the metal strip already has a relatively small thickness. Both the doubling of the tape head and the missing of the nip lead to negative results. In extreme cases, it is possible that the metal strip can only be used as scrap or that even the rolling train is damaged.

In the prior art, the side guides are usually set narrow to leave the metal strip only a small lateral range of motion. This also has the consequence that the band edges are ground through the side guides and that the band is braced in itself.

In practice, by quickly correcting the skew of the work rolls, control people try to influence the directional stability of the strip head in sight. This activity is very demanding and requires a lot of experience. In addition, even experienced control personnel often succeed only to a limited degree because the view from the control platform to the metal belt takes place at an unfavorable angle. Also, steam and dust often interfere with visibility. Furthermore, only sections of the metal strip between the rolling stands are visible. Moreover, because of the high transport speeds, a very fast reaction is required in the rear rolling mills of the rolling mill.

From DE 10 2014 215 397 AI an operating method for a rolling train is known in which a metal strip is rolled, which has a tape head. The rolling train has a front and a rear roll stand, between which side guides for the metal strip are arranged. In the case of DE 10 2014 215 397 A1, the lateral position of the tape head is detected by means of an optical detection device, and the

Tracking the employment of upstream rolling stand used. This procedure leads to good results.

The disadvantage, however, is that the optical detection device is required.

Summary of the invention

The object of the present invention is to provide opportunities to be able to adjust the band position quickly, easily and reliably. In this case, in particular, the presence of an independent detection device for the deviation of the lateral position of the metal strip from the desired position should not be required. Furthermore, the risk of band Doppler should be reduced or avoided.

The object is achieved by an operating method for a rolling train with the features of claim 1. Advantageous embodiments of the operating method are the subject of the dependent claims 2 to 10.

According to the invention, an operating method of the initially mentioned type is configured by

- That the band position controller determines the control command utilizing the time derivative of the deviation of the lateral position of the tape head of the desired position such that a change in the deviation of the lateral position of the tape head is counteracted by the desired position.

As a result of the force limitation, in contrast to the position-controlled operation of the state of the art, it is achieved that the corresponding side guide gives way when the metal strip is hit against the side guide. As a result, the forces exerted on the metal strip by the lateral guide are first of all limited. This reduces the risk of band Doppler. Due to the fact that the width of the metal strip is known and a side edge of the metal strip rests against the yielding side guide, the lateral position of the metal strip can continue to be detected quantitatively. But above all, the time derivative of the deviation of the lateral position of the tape head of the desired position is utilized in the determination of the control command and thus the control command determined such that a change in the deviation of the lateral position of the tape head of the desired position - mind you the change - counteracted , It can thereby be achieved that the metal strip runs as straight as possible out of the front roll stand by means of a finely metered counter-control. It is possible for the side guides to be adjusted in a force-controlled manner to the metal strip via a respective force regulator, and for the force regulator to be given a force setpoint effecting the force limitation. In this case, both side guides are always on the metal band. This has the advantage that even small deviations of the lateral position of the metal strip from the desired position can be detected easily.

In the case of a force control, preferably the force regulators are activated only at a time when the tape head has run out of the front rolling stand by a predetermined length. This ensures that the tape head can reliably run into the area between the two side guides. In particular, this avoids that the front, extending in the bandwidth direction strip edge abuts against one of the side guides and thereby causes a high-altitude.

In particular, the force regulators can determine a respective additional setpoint value for a respective lower-level position controller, by means of which a position control of the respective lateral guide takes place. Alternatively, it is possible that the side guides are moved position-controlled via a respective position controller to a respective reference position. The reference positions are in this case preferably predetermined such that the metal strip in the case of a central, completely straight transport from both side guides has a respective distance. In the case of position control, the position controllers each determine a force setpoint value for a respective subordinate force regulator as the respective manipulated variable. However, the respective force setpoint is limited to a force limit by means of a respective limiter. The limiters may be part of the respective position controller or stand-alone units arranged between the position controllers and the force controllers.

In the case of subordinate or superimposed position control, there is a tolerance range within which the metal strip can (usually slightly) emigrate without contacting the side guides. In this case, the strip edges are not damaged by the side guides at a central straight line of the metal strip.

Preferably, the band position controller determines the setting command such that the change in the deviation is reduced as much as possible, in particular to zero. As a result, as soon as possible, ideally as straight as possible, the metal strip runs out of the front rolling stand as soon as possible, at which point the change in deviation is reduced as much as possible.

When determining the setting command, the strip position controller preferably takes into account a current length by which the strip head in each case has run out of the front rolling stand. This results in a linearization of the adjustment of the band position controller.

Before entering the tape head in the front mill stand by means of a model of the mill train is a setting determines the front mill on which the front roll stand is set from the arrival of the tape head in the front roll stand. This setting is maintained until the deviation of the lateral position of the tape head from the desired position is detected by means of the side guides. The model is preferably adapted on the basis of the positioning command determined by the belt position controller, and the adapted model is used as the basis for determining the setting of the front rolling stand when rolling another metal belt.

As a result, the model can be gradually improved on and on, so that improved settings can be determined for future metal strips to be rolled.

In an analogous manner, prior to entry of the tape head into the rear mill stand, a model of the mill train can also be used to determine a setting of the rear mill stand to which the rear mill stand will be set at the time the tape head enters the rear mill stand. It is possible that, when determining the position of the rear roll stand, the positioning command for the front roll stand determined by the strip position controller and / or the deviation of the lateral position of the strip head from the desired position and / or the temporal change of the lateral position of the strip head are taken into account , As a result, tape travel may already be optimized for the currently rolled strip.

The object is further achieved by a computer program having the features of claim 11. According to the invention, the execution of the computer program causes the control device to operate the rolling train in accordance with an operating method according to the invention.

The object is further achieved by a control device for a rolling train with the features of claim 12. According to the invention, the control device is programmed with a computer program according to the invention, so that the control ereinrichtung operates the rolling mill according to an operating method according to the invention.

The object is further achieved by a rolling mill with the features of claim 13. According to the invention, the control device operates the rolling train in each case according to an operating method according to the invention.

Preferably, the front and the rear rolling stand are rolling stands of a rolling mill designed as a finishing train.

Short description of the drawing

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in more detail in conjunction with the drawings. Here are shown in a schematic representation:

1 shows a rolling train with several rolling stands,

2 shows two rolling mills of the rolling mill in perspective

View,

3 shows the two rolling stands of the rolling train of FIG. 2 from above,

4 shows a control arrangement,

5 shows a further control arrangement and

6 shows a further control arrangement. Description of the embodiments

According to FIG. 1, a metal strip 1 is to be rolled in a rolling train. The metal strip 1 is conveyed in a transport direction x through the rolling train. The metal strip 1 may be, for example, a steel strip, an aluminum strip, a copper strip, a brass strip or a band made of another metal. The rolling train has a plurality of rolling stands 2. As a rule, the rolling train is designed as a finishing train. As a result, the rolling stands 2 are generally the rolling stands 2 of a finishing train.

The number of rolling stands 2 is usually between four and eight, for example at five, six or seven. Of the rolling stands 2, only their work rolls 3 are shown in FIG. 1 (and also in the other figures). In general, however, the rolling mills 2, in addition to the work rolls 3 more rolls, in particular in Quartogerüsten in addition to the work rolls 3 backup rolls and Sextogerüsten in addition to the work rolls 3 backup rolls and intermediate rolls. The work rolls 3, the intermediate rolls and / or the backup rolls may be axially displaceable. However, this is not mandatory. Behind the last roll stand 2 are often a cooling section and / or a reel (not shown in the FIG) available.

The rolling train is controlled by a control device 4. The control device 4 usually controls the entire rolling train. So it is usually only once for all rolling stands 2 of the rolling mill available. However, a parameterization of the control device 4 with respect to the individual rolling stands 2 may be different from rolling stand 2 to rolling mill 2.

The control device 4 is generally designed as a software programmable control device 4. It is therefore usually programmed with a computer program 5. The computer program 5 determines the mode of action of the control device 4. The computer program 5 comprises machine code 6 which can be processed by the control device 4. The processing of the machine code 6 causes the control device 4 to operate the rolling mill in accordance with an operating method which will be explained in more detail below in conjunction with the further FIG.

The procedure according to the invention, which is explained in more detail below, is furthermore generally carried out for each pair of rolling mills. armor 2 seized. In the following, therefore, only a single pair of rolling stands 2 will be considered in connection with FIGS. 2 and 3 and also the further FIG. However, the corresponding embodiments can apply to any such group of two in the transport direction x of the metal strip 1 immediately successive stands 2.

The front roll stand 2 of FIGS. 2 and 3, i. the rolling stand from which the metal strip 1 runs out is the mainly relevant rolling stand 2. With regard to the rear rolling stand 2, it is essentially only necessary for the metal strip 1 to be guided to the rear rolling stand 2. Hereinafter, the reference numeral 2 a is used for the front stand 2, and the reference sign 2 b is used for the rear stand 2.

It is also important in many cases that the tape head 7 of the metal strip 1, i. Although the beginning of the metal strip 1 has already run out of the front rolling stand 2 a, the rear rolling stand 2 b has not yet reached. This condition is usually and also referred to below as running out of the tape head 7 from the front roll stand 2a. The rolling train furthermore has between each two rolling stands 2 - this is shown only in FIG. 3 for the area between the front and the rear roll stands 2 a, 2 b - side guides 8, 8 '. The side guides 8, 8 'are adjustable via corresponding adjusting devices 9, 9'. The adjusting devices 9, 9 'are generally designed as hydraulic cylinder units. However, the manner of adjustability is of minor importance in the context of the present invention. By means of the side guides 8, 8 ', the metal strip 1 is guided laterally.

The side guides 8, 8 '(more precisely: the adjusting devices 9, 9') are operated under power limitation in the context of the present invention. This applies at least during the period between the leakage of the tape head 7 from the front roll stand 2a and the running of the tape head 7 in the rear roll stand 2b. Forces F, F ', which are exerted by the side guides 8, 8' on the side edges 10, 10 'of the metal strip 1, are thus limited. In particular, the side guides 8, 8 'give way when the metal strip 1 exerts an excessive force on the side guides 8, 8', ie a force above a force limit Fmax. The force limit Fmax can be, for example, between 2 kN and 10 kN, in particular between 4 kN and 6 k. It can be predetermined as a parameter according to the representation in FIG. 3 of the control device 4. Irrespective of whether the force limit value Fmax is specified as a parameter or not, the force limit value Fmax is, however, kept constant in the context of the operating method according to the invention.

The respective position p, p 'of the side guides 8, 8' can be detected by means of corresponding sensors 11, 11 '. If the detection takes place while the tape head 7 is between the front roll stand 2a and the rear roll stand 2b, the positions p, p 'for the lateral position y of the tape head 7 and thus also for the deviation 5y of the lateral position y characteristic of a target position y *. This will be explained in more detail later in connection with two possible embodiments of the present invention. By means of the side guides 8, 8 ', the deviation 5y of the lateral position y of the tape head 7 can thus be detected quantitatively by a desired position y *. Thus, it can not be detected purely in binary that the deviation 5y has taken place and which direction the deviation 5y possibly has. Rather, it is also possible to detect the extent of the deviation 5y, ie to what extent the deviation 5y has taken place. The positions p, p 'can therefore be supplied to a determination device 12. The determination device 12 can use the detected positions p, p ', the lateral position y of the tape head 7 and the deviation 5y of the lateral position y of the tape head 7 from the desired position y * determine.

The lateral position y can, as required, be related to one of the two side edges 10, 10 'or to a location between the two side edges 10, 10', in particular the band center. In the following, it is assumed that the lateral position y is related to the center of the strip-indicated in FIG. 3 by a dashed line. This definition facilitates arithmetic and explanation of the invention, but is not limited in content.

As shown in FIG. 3, the control device 4 often implements a tape position controller 13 for the front rolling stand 2a while processing the computer program 5. The band position controller 13 may be formed, for example, as a conventional PI controller. Alternatively, the band position controller can be designed, for example, as a model-predictive controller. The band position controller 13 is supplied with the deviation 5y. The band position controller 13 determines a setting command S for the front rolling stand 2a. By means of the control command S, the change of the deviation 5y (ie not the absolute value of the deviation 5y, but the speed with which the tape head 7 emigrates laterally) is counteracted. The rolling stand 2a is acted upon in accordance with the determined positioning command S. The control command S can in particular cause a differential rolling force or a differential rolling gap. The belt position controller 13 acts on the front rolling stand 2a in accordance with the determined control command S.

In a possible embodiment of the present invention, the side guides 8, 8 'as shown in FIG 4 via a respective force regulator 14, 14' operated on the metal strip 1 kraftgere-. The force regulators 14, 14 'are implemented by the control device 4 on the basis of the execution of the computer program 5. The force regulators 14, 14 'may be designed as conventional regulators, in particular especially as P-controller or PI controller. The two force regulators 14, 14 'are uniformly given the force limit value Fmax as the force setpoint value F *, F' *. Corresponding to the difference between force setpoint value F *, F '* and the respective force actual value F, F', the two force regulators 14, 14 'determine corresponding control commands q, q' for the adjusting devices 9, 9 'and control them accordingly. The specification of the force limit value Fmax as a force setpoint value F *, F '* for both force regulators 14, 14' causes the force limitation in this case.

In the case of the force control are both side guides 8, 8 'on the side edges 10, 10' at. It is therefore possible in principle to form the mean value of the two positions p, p 'and to use this value for the lateral position y: p + p'

y = (1)

2

Preferably, however, only one of the two positions p, p 'is used. In particular, it is possible, based on the positions p, p ', to determine to which side the metal strip 1 is deflected, and to utilize only the position p, p' on this side. Thereby, the accuracy of the determination of the lateral position y can be improved. In order to determine to which side the metal strip 1 is deflected, for example, the sign of the sum of the positions p, p 'can be evaluated. Depending on the direction of the deflection then the lateral position y - depending on the sign - can be determined according to one of the two equations below, where b is the width of the metal strip 1 which is known without further ado:

In the case of a pure force control are both side guides 8, 8 'on the side edges 10, 10' at. To ensure proper Accordingly, to ensure proper insertion of the tape head 7 in the area between the two side guides 8, 8 ', preferably the force regulator 14, 14' activated only at a time at which the tape head 7 expired from the front roll stand 2a by a predetermined length Lmin is. The predetermined length Lmin is larger than the distance of the side guides 8, 8 'from the front rolling stand 2a, as shown in FIG. Only after that point in time are the force regulators 14, 14 activated and thereby the side guides 8, 8 'are set against the side edges 10, 10'.

Previously, for example, a position control can be active, which keeps the side guides 8, 8 'in a retracted position. The respective actual length L, by which the tape head 7 has run out of the front rolling stand 2a, can be determined, for example, by integrating a transport speed v at which the metal strip 1 leaves the rolling stand 2a.

In a further possible embodiment of the present invention, the force regulators 14, 14 'act via lower-level position controllers 15, 15' on the side guides 8, 8 '. In this case, a position control of the respective lateral guide 8, 8 'takes place by means of the subordinate position controllers 15, 15'. For this purpose, the position regulators 15, 15 'corresponding to the representation in FIG 5 corresponding reference positions p *, p' * and the associated positions p, p 'are supplied.

The reference positions p *, p '* are determined such that their difference is slightly larger than the width b of the metal strip 1: p * -p' * = b + S (4) δ is a suitably selected barrier. For example, it can be in the range of a few centimeters. As a rule, it is a maximum of 20 cm. The force regulators 14, 14 'determine a respective additional setpoint value δρ, δρ' for the respective subordinate position regulator 15, 15 '. In this case, the force regulators 14, 14 'are generally designed as I-controllers, ie they have an integrating effect. Furthermore, the force regulators 14, 14 'in this case usually a respective limiter 16, 16' downstream, by means of which the output signal of the respective force regulator

14, 14 'is limited on one side. It is thereby achieved that by means of the force regulators 14, 14 'a yielding of the side guides 8, 8' can be effected, but not a closing of the side guides 8, 8 '.

In a further possible embodiment of the present invention, the side guides 8, 8 'as shown in FIG 6 via a respective position controller

15, 15 'position controlled to a respective reference position p *, p' * driven. The reference positions p *, p '* are, as explained above in connection with FIG. 5, determined such that their difference is slightly greater than the width b of the metal strip 1.

In this case, the two position controllers 15, 15 '- independently of one another - each determine a force setpoint value F *, F' * as the respective manipulated variable. The two force setpoint values F *, F '* are supplied to limiters 16, 16'. In the limiters 16,

16 ', the force setpoint values F *, F' * are limited on one side to the uniform force limit value Fmax. The - possibly limited - force setpoint values F *, F '* are then fed to the force regulators 14, 14'. The force regulators 14, 14 'are in the embodiment of FIG 6 the position controllers 15,

15 underlain. They determine - as before in the case of the force control according to FIG. 4 - according to the difference between the respective (optionally limited) force set point F *, F '* and the respective force actual value F, F' corresponding control commands q, q 'for the actuators 9 , 9 'and control them accordingly. In the case of force control with subordinate position control and also in the case of position control with force limitation and subordinate force control is usually at most one of the two side guides 8, 8 'to the respective adjacent side edge 10, 10' on. The other side guide 8 ', 8 is spaced from its adjacent side edge 10', 10. Only the position p, p 'of the side guide 8, 8', which bears against its associated side edge 10, 10 ', can be used to quantitatively determine the lateral position y. Which of the two side guides 8, 8 'this is, can be readily determined by the forces F, F' and the positions p, p '. In particular, that side guide 8, 8 'which does not contact its side edge 10, 10' is located at its respective reference position p *, p '*. Also, for holding this side guide 8, 8 'in the absence of contact with the corresponding side edge 10, 10' no force F, F 'required. This force F, F 'therefore has the value 0. For the determination of the deflected lateral guide 8, 8 'can be used in particular one condition, the other conditions or a combination of both conditions.

As part of the determination of the control command S, the band position controller 13, as already mentioned, does not use the deviation 5y of the lateral position y from the target position y *, but rather the time derivative, ie the speed with which the tape head 7 emigrates laterally. As part of the determination of the setting command S, the band position controller 13 can continue to take into account the actual length L and possibly also other variables such as, for example, the transport speed v. As a result, the behavior of the control can be linearized. Optionally, the band position controller 13 can continue to make a smoothing and / or a limitation of the control command S.

Preferably, the band position controller 13 determines the setting command S such that the change in the deviation 5y is reduced as much as possible, in particular to zero. par- dere means the reduction of the change of the deviation 5y to zero, that the metal strip 1 from this point straight out of the front roll stand 2a expires. This control is thus the desired control of the roll stand 2a. On the other hand, the control command S is not determined so that the deviation 5y itself is reduced as much as possible.

Due to the execution of the computer program 5 or of the machine code 6, the control device 4 implements inter alia a model 17 of the rolling train. The control device 4 uses the model 17 to determine an adjustment of the respective rolling stand 2, to which the respective rolling stand 2 is set. This determination is made before the running of the tape head 7 in the respective rolling stand 2. The determined setting applies to the time from the arrival of the tape head 7 in the respective rolling stand 2 or - hereby substantially equivalent - for the time at which the tape head. 7 reaches the respective rolling mill 2. This applies to each rolling stand 2 of the rolling train and thus also to the front rolling stand 2a and the rear rolling stand 2b. The setting determined by means of the model 17 for the front rolling stand 2 a is maintained until the deviation 5 y of the lateral position y of the tape head 7 from the desired position y * is detected by means of the side guides 8, 8 '. Up to this time, therefore, there is no correction of the setting of the front rolling stand 2a. Without further measures, therefore, a subsequent further metal strip 1 is first rolled with the same, possibly erroneous settings. Preferably, therefore, the model 17 is adapted by means of the positioning command S determined by the band position controller 13. This makes it possible to use the adapted model 17 when rolling the additional metal strip 1 to determine the setting of the front rolling stand 2a. The control command S is the control command S in which the variation of the deviation 5y is reduced as much as possible.

In the simplest case, despite the tracking of the setting of the front roll stand 2a, the advance by means of the model 17 determined setting of the rear roll stand 2b kept unchanged. However, it is alternatively possible, in determining the setting of the rear roll stand 2b, the adjustment command S determined by the strip position controller 13 for the preceding roll stand 2a and / or the deviation 5y of the lateral position y of the strip head 7 from the desired position y * and / or to take into account the temporal change of the lateral position y, so to correct the previously determined setting. This correction can also be done without adaptation of the model 17. In particular, the model 17 may be designed such that it determines the setting of the rolling stands 2 taking into account the variables mentioned. Again, the control command S is that control command S, in which the change in the deviation 5y is reduced as much as possible.

The control device 4, which implements the implementation of the operating method according to the invention, is designed in such a way on the basis of the programming with the computer program 5. The computer program thus effects, as shown in FIGS. 3, 4 and 5, that the control device 4 implements corresponding software blocks.

The invention has many advantages. In particular, the side guides 8, 8 'are usually present anyway. There are therefore no additional means required to determine the lateral position y of the tape head 7. Furthermore, damage to the side edges 10, 10 'and also to the side guides 8, 8' can be reliably avoided due to their force limitation. The risk of band Doppler can also be significantly reduced. Nevertheless, it can be ensured in a simple manner that the metal strip 1 ends as straight as possible out of the front rolling stand 2a.

Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be made by those skilled in the art can be derived without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1 metal band

2 rolling stands in general

2a front mill stand

2b rear rolling stand

3 work rolls

4 control device

5 computer program

6 machine code

7 tape head

8, 8 'side guides

9, 9 'adjusting devices

10, 10 'side edges

11, 11 'sensors

12 determination device

13 band position controller

14, 14 'force regulator

15, 15 'position regulator

16, 16 'limiter

17 model

b width

Force values

F, F 'forces

Fmax force limit

L current length

Lmin predetermined length

p, p 'positions

p *, p '* reference positions

q, q 'Control commands for control devices

S Control command for front mill stand

V Transport speed

X transport direction

y lateral position

y * target position

δ barrier

δρ, δρ 'additional setpoints

δγ deviation

Claims

claims

1. Operating method for a rolling train, in which a metal strip (1) is rolled, which has a strip head (7), - wherein the rolling mill at least one front rolling stand (2a) and a rear rolling stand (2a) downstream of the rear rolling stand (2b) and further comprises between the two rolling stands (2a, 2b) side guides (8, 8 ') for the metal strip (1),

- Wherein the side guides (8, 8 ') are operated with power limitation,

- during the period between the expiry of the

Tape head (7) from the front roll stand (2a) and the running of the tape head (7) in the rear roll stand (2b) by means of the side guides (8, 8 ') a deviation (5y) of the lateral position (y) of the tape head (7 ) is detected quantitatively from a desired position (y *),

wherein a positioning command (S) for the front roll stand (2a) is determined by means of a strip position controller (13),

- Wherein the front roll stand (2a) from the band position controller (13) is acted upon in accordance with the determined control command (S) and

- Where the band position controller (13) the adjusting command (S) using the time derivative of the deviation (5y) of the lateral position (y) of the tape head (7) of the desired position

(y *) determined such that a change in the deviation (5y) of the lateral position (y) of the tape head (7) from the desired position (y *) is counteracted.

2. Operating method according to claim 1,

characterized ,

in that the side guides (8, 8 ') are adjusted in a force-controlled manner to the metal strip (1) via a respective force regulator (14, 14') and that the respective force regulator (14, 14 ') has a force setpoint (F *, F') effecting the force limitation. *).

3. Operating method according to claim 2,

characterized ,

in that the force regulators (14, 14 ') are activated only at a time when the tape head (7) has run out of the front rolling stand (2a) by a predetermined length (Lmin).

4. Operating method according to claim 2 or 3,

characterized ,

the force regulators (14, 14 ') determine a respective additional desired value (δρ, δρ') for a respective lower-level position controller (15, 15 ') by means of which a position control of the respective lateral guide (8, 8') takes place.

5. Operating method according to claim 1,

characterized ,

in that the side guides (8, 8 ') are moved in position-controlled manner over a respective position controller (15, 15') to a respective reference position (p *, p '*) that the position controllers (15, 15') each as the respective manipulated variable determine a force setpoint value (F *, F '*) for a respective subordinate force regulator (14, 14') and that the respective force setpoint value (F *, F '*) by means of a respective limiter (16, 16') to a force limit (Fmax ) is limited.

6. Operating method according to one of the above claims, d a c o v e c e s e c e n e,

in that the band position controller (13) determines the setting command (S) such that the change in the deviation (5y) is reduced as far as possible, in particular to zero.

7. Operating method according to one of the above claims, d a a c e c e s e c e n e c e,

that the band position controller (13) in the determination of the control command (S) takes into account a current length (L) by which the tape head (7) in each case has run out of the front rolling stand (2a).

8. Operating method according to one of the above claims, d a d u c h e c e n e c e n e,

in that, before the strip head (7) enters the front rolling stand (2a), a setting of the front rolling stand (2a) is determined by means of a model (17) of the rolling line, to which the front rolling stand (2a) from the running in of the strip head (7) in the front roll stand (2a) is set until by means of the side guides (8, 8 ') the deviation (5y) of the lateral position (y) of the tape head (7) from the target position (y *) is detected in that the model (17) is adapted on the basis of the positioning command (S) determined by the band position controller (13) and that the adaptation of the setting of the front rolling stand (2a) is based on the adapted model (17) when rolling a further metal band (1) ,

9. Operating method according to one of the preceding claims, d a d e r c h e c e n e c e n e,

in that prior to running the tape head (7) into the rear rolling stand (2b) by means of a model (17) of the rolling train, a setting of the rear rolling stand (2b) to which the rear rolling stand (2b) is adjusted at the time is determined to which the tape head (7) enters the rear stand (2b), and that in determining the setting of the rear stand (2b), the adjustment command (S) for the front stand determined by the tape position controller (13)

(2a) and / or the deviation (5y) of the lateral position (y) of the tape head (7) from the desired position (y *) and / or the temporal change of the lateral position (y) of the tape head (7) are taken into account.

10. Operating method according to one of the above claims, d a a c e c o v e c e s e c e n e,

in that the front and rear rolling stands (2a, 2b) are rolling stands (2a, 2b) of a rolling train designed as a finishing train.

11. Computer program comprising machine code (6), which can be processed by a control device (4) for a rolling mill wherein the execution of the machine code (6) by the control device (4) causes the control device (4) to operate the rolling train in accordance with an operating method according to one of the preceding claims.

12. A control device for a rolling mill, wherein the control device is programmed with a computer program (5) according to claim 11, so that the control device operates the rolling mill according to an operating method according to one of claims 1 to 10.

13. rolling line for rolling a metal strip (1) having a tape head (7),

- wherein the rolling train has at least one front rolling stand (2a) and a rear rolling stand (2a) downstream of the rear rolling stand (2b) and further between the two rolling stands (2a, 2b) side guides (8, 8 ') for the metal strip (1) having,

- wherein the rolling train comprises a control device (4) which operates the rolling train according to an operating method according to one of claims 1 to 10.

14. rolling mill according to claim 13,

characterized ,