DETERMINATION OF THE LATERAL OFFSET OF A METAL STRIP USING THE CONTOUR OF A COIL'S END END

Description

field of technology

[0001] The present invention relates to an operating method for a rolling mill which has at least one rolling stand and a reel arranged upstream of the rolling stand, wherein in the rolling mill a metal strip wound into a coil is unwound from the uncoiler, fed from there to the rolling stand and rolled in the rolling stand, wherein a control device for the rolling stand, taking into account a respective lateral offset that a respective section of the metal strip has at a predetermined distance in front of the rolling stand, determines a respective control variable for at least one actuator assigned to the rolling stand and controls the actuator according to the determined respective control variable.

[0002] The present invention further relates to a control program for a control device of a rolling mill for rolling a metal strip, wherein the control program comprises machine code that can be processed by the control device, wherein the processing of the machine code by the control device causes the control device to be operated in accordance with such an operating procedure.

[0003] The present invention further relates to a control device for a rolling stand of a rolling plant, wherein the control device is programmed with such a control program, so that the control device executes such a control program during operation.

[0004] The present invention further relates to a rolling mill comprising at least one rolling stand, a reel arranged upstream of the rolling stand and a control device for the rolling stand. State of the art

[0005] Such an operating procedure is known, for example, from DE 34 13 269 C2. Summary of the invention

[0006] When a metal strip is rolled, the rolled strip often migrates laterally, meaning it migrates in the width direction of the strip. This migration can occur both at the entry and exit sides of a rolling stand. Consequently, in a multi-stand rolling mill, it can also occur between the individual stands.

[0007] Minor lateral movement is often unproblematic. However, with larger lateral movements, the metal strip can collide with a side guide, resulting in a so-called "rise." Furthermore, lateral movement affects quality parameters of the rolled metal strip, such as profile, flatness, and thickness wedge. This also applies to minor lateral movements of the metal strip.

[0008] It is known in the prior art to detect the lateral displacement of the metal strip at the exit end of the rolling stand – for example, by means of a camera – and to adjust a control variable for an actuator of the rolling stand depending on the displacement detected at the exit end. Reference can be made, purely by way of example, to EP 3 202 502 A1.

[0009] It is also known to detect the lateral offset of the metal strip at the entry side of the rolling stand and to adjust a control variable for an actuator of the rolling stand depending on the offset detected at the entry side. For example, reference can be made to the aforementioned DE 34 13 269 C2.

[0010] In DE 34 13 269 C2, the lateral offset of a section of the metal strip is recorded on the entry side of the rolling stand and used within the framework of a conventional control system (for example, a proportional control system).

[0011] The procedure described in DE 34 13 269 C2 is only practical if the metal strip is a flat metal strip, i.e., not in the coiled state of the metal strip.

[0012] The object of the present invention is to create possibilities by means of which it is possible to take into account the lateral offset of a respective section of the metal strip even when the metal strip is coiled and uncoiled before the metal strip is rolled in the rolling stand.

[0013] The problem is solved by an operating method with the features of claim 1. Advantageous embodiments of the operating method are the subject of dependent claims 2 to 4.

[0014] According to the invention, an operating method of the type mentioned at the outset is designed in such a way that the control device is informed once of a contour of at least one end face of the coil still wound up before the metal strip is unwound, so that the control device has the information for the lateral offset of the sections over the entire length of the metal strip available to it even before the metal strip is fed to the rolling stand, and that the control device determines the respective lateral offset using the contour.

[0015] The actuator can be, in particular, an actuator that allows for an asymmetrical adjustment of the roll gap. This allows direct influence on the lateral strip travel. A typical example of such an actuator is a wedge adjustment of the roll gap. Alternatively or additionally, control variables for other actuators can also be determined, especially for actuators that effect only a local or a global but symmetrical influence on the profile and flatness of the metal strip. A typical example of a locally acting actuator is a cooling device that, viewed in the width direction of the metal strip, only affects a single section of a work roll. A typical example of a globally but symmetrically acting actuator is roll bending. Another typical example is roll displacement.

[0016] In the simplest case, the manipulated variable is determined using a conventional setpoint-actual control system, for example, a proportional (P) controller, a pi (PI) controller, or a PID (Pulse Interference Diagonal) controller. However, because the contour of the end face already determines the lateral offset profile along the entire length of the metal strip, more complex control systems are also possible, such as model predictive control. Furthermore, other predictive approaches to the lateral offset profile are also possible. For example, offline optimization of the manipulated variable can be performed in advance along the entire strip length.

[0017] Typically, the control unit only receives information about the contour of a single end face of the coil. In this case, assuming that the width of the metal strip is constant along its length, the control unit can only determine the lateral offset.

[0018] Alternatively, the control unit can also be provided with the contours of both ends of the coil. In this case, the control unit can not only determine the respective lateral offset, but also, for example, determine the width of the metal strip for each section and take this into account when controlling the rolling stand. This is particularly advantageous if the width of the metal strip can be influenced by the actuator. In this case, the actuator can be an actuator of the rolling stand itself or an actuator associated with the rolling stand, such as a loop lifter or a swaging device located upstream or downstream of the rolling stand.

[0019] In principle, the contour of the end face can be captured at any time after the metal strip has been wound onto the coil, particularly immediately after winding or at any other time between winding and feeding to the unwinder. Preferably, however, the contour of the end face is captured by a detection device assigned to the unwinder while the coil is already in the unwinder, and then fed to the control unit. This reduces the dependence of the operating procedure on externally supplied or provided data.

[0020] The detection device can be, for example, a thermal imaging camera or a camera that uses light in the visible spectrum to capture conventional two-dimensional images. It can also be a camera that captures depth images. Alternatively, the detection device can be a laser scanner that scans the contour of the front surface. Other configurations are also possible. All of the types of detection devices mentioned are generally known to experts.

[0021] In a preferred embodiment of the operating method, the contour of the coil's end face is known to the control device in the form of a contour line extending radially inward to radially outward with respect to the coil's end face. This contour line thus indicates the lateral position of the detected strip edge as a function of its distance from the coil's eye. In this case, the control device determines the respective lateral offset using this contour line.

[0022] Alternatively, the contour of the coil's end face can be known to the control device as a two-dimensional contour surface relative to the coil's end face. In this case, direct use of the two-dimensional contour surface is possible. Preferably, however, the control device uses this contour surface to determine a contour line running radially inward to radially outward, relative to the coil's end face, and further determines the respective lateral offset using this contour line, but not the two-dimensional contour surface itself. As before, the contour line indicates the lateral position of the detected strip edge as a function of its distance from the coil's eye.

[0023] Using the contour line significantly reduces the computational effort required to determine the respective lateral offset.

[0024] Based on the contour line, the control unit initially knows the offset of each section of the metal strip at a current coil radius (i.e., its current position on the radial contour line). This position corresponds to a support point in the longitudinal direction of the metal strip. The distance to the next support point is calculated by multiplying the current coil radius by a factor of 2π. The new coil radius is then determined by the current coil radius and the thickness of the coiled metal strip. When working from the outside in, the coil radius decreases, meaning the thickness of the coiled metal strip is subtracted. Conversely, when working from the inside out, the coil radius increases, meaning the thickness of the coiled metal strip is added. Thus, the control unit only knows the offset of the corresponding sections of the metal strip at support points that follow one another in the longitudinal direction of the strip, based solely on the contour line.The support points are not equidistant because the coil radius varies. However, this is of minor importance.

[0025] It is possible that the sections of the metal strip are defined by the support points as such, i.e., a 1:1 mapping is performed. Alternatively, however, it is also possible to perform interpolation as needed. The interpolation can be linear or non-linear, as required.

[0026] Within the framework of the operating method according to the invention, the metal strip can be cold-rolled or hot-rolled in the rolling stand as required. Particularly in hot-rolling, the rolling mill can, for example, be designed as a Steckel mill. In cold-rolling, on the other hand, the rolling stand can be, in particular, the leading rolling stand of a tandem mill.

[0027] The problem is further solved by a control program with the features of claim 5. According to the invention, the execution of the control program by the control device causes, that the control device receives a contour of at least one end face of the coil still wound up before the metal strip is unwound from a unwinder located upstream of the rolling stand, so that the control device has information about a lateral offset that sections of the metal strip have at a predetermined distance in front of the rolling stand over the entire length of the metal strip, that the control device determines the respective lateral offset for the sections using the contour, and that the control device determines a respective control variable for at least one actuator assigned to the rolling stand using the respective lateral offset and controls the actuator according to the determined respective control variable.

[0028] The tax software can also be designed in an advantageous way. The design of the tax software corresponds to the advantageous design of the operational procedures. The same applies to the advantages achieved thereby.

[0029] The problem is further solved by a control device with the features of claim 8. According to the invention, the control device is programmed with a control program according to the invention, such that the control device executes the control program according to the invention during operation.

[0030] The problem is further solved by a rolling mill with the features of claim 9. According to the invention, in a rolling mill of the type mentioned at the outset, the control device is designed as a control device according to the invention.

[0031] Preferably, a detection device is associated with the uncoiler, by means of which the contour of the end face is detected while the coil is already in the uncoiler, and then fed to the control unit. This means that the operation of the rolling mill according to the invention is less dependent on externally supplied or provided data.

[0032] The rolling stand of the rolling mill can be configured as either a hot rolling stand or a cold rolling stand, depending on requirements. In the former case, the rolling mill can be configured as a Steckel mill. In the latter case, the rolling stand can be the foremost rolling stand of a multi-stand tandem mill. Brief description of the drawings

[0033] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings. These drawings show, in schematic representation: FIG 1 a rolling mill, FIG 2 another rolling mill, FIG 3 a flow diagram, FIG 4 a section along a line IV-IV in the FIG 1 und 2 , FIG 5 a flowchart, FIG 6 a perspective view of an end face of a coil and FIG 7 a flowchart. Description of the embodiments

[0034] According to FIG 1 A rolling mill has a rolling stand 1. Only the work rolls of the rolling stand 1 are shown. In the design according to FIG 1 Rolling stand 1 is the only rolling stand in the rolling mill. A coiler 2 is located upstream of rolling stand 1. A coil 3, i.e., a coiled metal strip 4, is unwound from the coiler 2. The unwound metal strip 4 is fed from the coiler 2 to rolling stand 1. The metal strip 4 is rolled in rolling stand 1. The coil 3 may have been fed to the coiler 2 as such, i.e., as a previously coiled metal strip 4. Alternatively, the metal strip 4 may have been coiled into the coil 3 by the coiler 2 itself before being unwound.

[0035] In the design according to FIG 1 A coiler 5 is further subordinate to the rolling stand 1. The metal strip 4 is coiled onto the coiler 5 after rolling in the rolling stand 1. The operation of a rolling mill is generally carried out according to... FIG 1 The metal strip 4 is rolled in reverse in the rolling stand 1, meaning that the ends of the metal strip 4 are not rolled along with it. The uncoiler 2 and the reel 5 therefore change their respective functions with each rolling pass. In particular, in this configuration, the metal strip 4 is alternately wound and then unwound by one and the same reel 2, 5.

[0036] The rolling mill according to FIG 1 can be configured in particular as a Steckel mill. In a Steckel mill, the metal strip 4 is hot rolled. In this case, the rolling stand 1 is therefore configured as a hot rolling stand. However, hot rolling of the metal strip 4 is also possible with other configurations of the rolling mill. For example, hot rolling of the metal strip 4 can also take place in a multi-stand hot rolling mill, in which the uncoiler 2 is located upstream of the hot rolling mill. This is also possible with a rolling mill configuration as described in FIG 1 The rolling mill stand 1 is shown to be a pre-stand.

[0037] FIG 2 shows an alternative design of a rolling mill. According to FIG 2 The rolling mill has, in addition to rolling stand 1, further rolling stands 6. In this case, rolling stand 1 is the foremost rolling stand of a multi-stand rolling mill. Of the rolling stands 1 and 6, the following are analogous to... FIG 1 Only the working rollers are shown.

[0038] Even in the design according to FIG 2 A coiler 2 is arranged upstream of the rolling stand 1. A coil 3, i.e., a previously coiled metal strip 4, is fed to the coiler 2. The metal strip 4 is uncoiled from the coiler 2 and from there fed to the rolling stand 1 (and subsequently to the other rolling stands 6). The metal strip 4 is rolled in the rolling stand 1 (and also in the other rolling stands 6).

[0039] As already mentioned, the design according to FIG 2 Hot rolling of the metal strip 4 takes place. According to FIG 2 However, an S-roll set 7 is arranged between the uncoiler 2 and the rolling stand 1. This configuration is particularly common in a multi-stand tandem mill where the metal strip 4 is cold-rolled. Cold-rolling of the metal strip 4 is also possible in other configurations of the rolling mill.

[0040] Both at the rolling mill according to FIG 1 as well as at the rolling mill according to FIG 2 At least the rolling stand 1 (usually the entire rolling mill) is controlled by a control unit 8. The control unit 8 is programmed with a control program 9, so that the control unit 8 executes the control program 9 during operation. The control program 9 comprises machine code 10, which can be processed by the control unit 8. The processing of the machine code 10 by the control unit 8 causes the control unit 8 to operate at least the rolling stand 1 – as already mentioned, usually the entire rolling mill – according to an operating procedure, which is described below in conjunction with FIG 3 will be explained in more detail.

[0041] According to FIG 3 In step S1, the control device 8 receives information about the contour K of at least one of the two end faces 11 of the coil 4. It is also possible that the control device 8 receives information about the contour K of both end faces 11 of the coil 4 in step S1. However, as a rule, the contour K of one of the two end faces 11 is sufficient. Therefore, this case is assumed below. Step S1 is performed by the control device 8 before the metal strip 4 is unwound.

[0042] In step S2, the control unit 8 determines a lateral offset V for each section i (i = 1, 2, 3, ...) of the metal strip 4. The offset V can therefore vary across the sections i. In the width direction of the metal strip 4, the offset V corresponds to the deviation of the centerline of the metal strip 4 from the centerline of the rolling stand 1. The offset V of each section i is determined for a predetermined distance that the respective section i has from the rolling stand 1. The offset V is determined using the contour K.

[0043] The predetermined distance can be determined as required. In particular, it can be the point where the metal strip 4 separates from the remaining part of the coil 3. This determination of the predetermined distance can be especially useful if there are no devices between the uncoiler 2 and the rolling stand 1 that influence or impede lateral movements of the metal strip 1. However, it can also be a different location. For example, in the case of the design of FIG 2 The predetermined distance can be determined by the location of the S-roller set 7. Which location is chosen depends on the circumstances of the individual case.

[0044] In step S3, the control unit 8 determines a respective manipulated variable C for at least one actuator 12. The actuator 12 can be an actuator of the rolling stand 1 itself, for example, acting locally or globally on the roll gap. Alternatively, the actuator 12 can be located upstream or downstream of the rolling stand 1. The determination of the respective manipulated variable C applies to the respective section i of the metal strip 4. The respective manipulated variable C is determined by the control unit 8 using the respective lateral offset V. Suitable actuators 12, suitable manipulated variables C, and suitable determination methods are known to those skilled in the art. In step S4, the control unit 8 controls the actuator 12 according to the determined respective manipulated variable C.

[0045] Step S1 is performed only once, namely once before the metal strip 4 is fed to the rolling stand 1. Step S4 is performed iteratively, namely for each individual section i of the metal strip 4. Steps S2 and S3 can be performed either only once or iteratively. The procedure for steps S2 and S3 is at the discretion of the person skilled in the art. Often it will be advantageous to perform step S2 together with step S1, i.e., once beforehand, and to perform step S3 together with step S4, i.e., iteratively.

[0046] The manner in which the contour K of the end face 11 is communicated to the control unit 8 can be determined as required. For example, the contour K can be specified to the control unit 8 by an operator or by a higher-level control unit. Preferably, however, a detection device 13 is assigned to the unwinder 2, by means of which the contour K of the end face 11 is detected while the coil 3 is already in the unwinder 2. In this case, the detection device 13 transmits the detected contour K to the control unit 8. The control unit 8 receives the detected contour K from the detection device 13. In this way, the contour K is communicated to the control unit 8.

[0047] The following will be discussed in connection with the FIG 4 and 5 a preferred method has been determined in which the contour K can be made available to the control device 8.

[0048] FIG 4 shows a section along a line IV-IV in the FIG 1 und 2 . According to FIG 4 Coil 3 has a coil eye 14. The coil eye 14 has a diameter D1. R1 = D1 / 2 is therefore the minimum radius of coil 3. Coil 3 also has an outer diameter D2. R2 = D2 / 2 is therefore the maximum radius of coil 3. The metal strip 4 has a thickness d. The individual turns 15 of coil 3 are spaced apart in the radial direction of coil 3 (i.e., viewed from the inside out or vice versa, from the outside in) by the thickness d of the metal strip 4. Furthermore, the individual turns 15 of coil 3 are slightly offset laterally (i.e., viewed in the width direction of the metal strip 4). The contours K of the end faces 11 follow the slight lateral offset of the turns 15. Along the section line IV-IV (see FIG 1 und FIG 2 Viewed from this perspective, a contour line KL is thus obtained with respect to the corresponding end face 11 of the coil 3, which describes the offset of the turns 15 as a function of the respective current coil radius r in the range from R1 to R2, i.e., from radially inward to radially outward (or vice versa). A completely analogous contour line KL would also result if the intersection line through the coil 3 were laid differently.

[0049] It is accordingly FIG 5 It is possible that the control device 8 receives the contour K of the end face 11 of the coil 3 in the form of such a contour line KL in a step S11.

[0050] The location of the outermost coil 15 corresponds to the beginning of the metal strip 4. The value of the contour line KL at this point corresponds to the offset of the foremost section i=1 of the metal strip 4. The radius r for the next inner coil 15 can be easily determined by subtracting the thickness d of the metal strip 4 from the radius r. At this point on the metal strip 4, the contour line KL can be re-evaluated by the control unit 8. This procedure can be repeated successively for all coils 15 of the metal strip 4. Thus, in a single step S12, the control unit 8 can successively determine the lateral offset of the metal strip 4 at this point for all coils 15 and therefore for support points that are spaced apart by a distance of 2πr (where the current coil radius r is variable). This results in a functional progression for the lateral offset of the metal band 4 over the entire length of the metal band 4.Based on this offset, the lateral offset V for sections i can easily be determined.

[0051] In the simplest case, the segments i are determined by the support points. In this case, the segments i are not of equal size. If the segments i are to be of equal size or satisfy another criterion, interpolation between adjacent support points can be performed as needed.

[0052] Steps S11 and S12 thus correspond to a possible implementation of steps S1 and S2 of FIG 3 .

[0053] The following will be discussed in connection with the FIG 6 and 7 another preferred way in which the contour K can be made available to the control device 8 was determined.

[0054] FIG 6 Figure 1 shows a perspective view of an end face 11 of the coil 3. Using suitable detection devices 13, it is readily possible to determine a contour surface KF that reflects, so to speak, the three-dimensional "displacement rock" across the entire end face 11. For example, if the detection device 13 is designed as a laser scanner, a two-dimensional scan of the entire end face 11 can be performed. However, other approaches are also possible.

[0055] It is accordingly FIG 7 It is possible that the control device 8 receives the contour K of the end face 11 of the coil 3 in the form of such a contour surface KF in step S21. In this case, the control device 8 can, for example, determine a contour line KL based on the contour surface KF in step S22. In particular, the control device 8 can select and evaluate a narrow strip of the contour surface KF running from radially inside to radially outside. In step S23, the control device 8 can then determine the respective lateral offset V of the sections i using the contour line KL. The contour surface KF itself is no longer required for the execution of step S23. Thus, step S23 can be performed by FIG 7 In terms of content, especially with step S12 of FIG 5 correspond.

[0056] Steps S21 to S23 thus correspond to another possible implementation of steps S1 and S2 of FIG 3The present invention offers many advantages. By capturing the contour K of an end face 11, information for the lateral offset V of the sections i is readily available along the entire length of the metal strip 4. This allows, in particular, the implementation of superior control algorithms. Acquisition directly at the uncoiler 2 enables independent data acquisition that does not rely on external inputs. Furthermore, it ensures that effects occurring before uncoiling are reliably detected and taken into account. The solutions according to the invention are simple, robust, and reliable, and can also be retrofitted to existing rolling mills.

[0057] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variants can be derived from them by the person skilled in the art without departing from the scope of protection of the attached claims. Reference symbol list

[0058] 1 Rolling stand 2 Uncoiler 3 Coil 4 Metal strip 5 Coiler 6 Other rolling stands 7 S-roll set 8 Control device 9 Control program 10 Machine code 11 End faces 12 Actuator 13 Detection device 14 Coil eye 15 Turns CSetting parameter D1, D2Diameter dBand thickness iSections of the metal strip KContour KFContour surface KLContour line R1, R2, rRadiuses S1 to S23Steps VOffset

Claims

1. Operating method for a rolling mill which has at least one rolling stand (1) and an uncoiler (2) arranged upstream from the rolling stand (1), - wherein, in the rolling mill a metal strip (4) coiled into a coil (3) is uncoiled by the uncoiler (2), is supplied from there to the rolling stand (1), and is rolled in the rolling stand (1), - wherein a control device (8) for the rolling stand (1) calculates, utilizing a respective lateral offset (V) which a respective portion (i) of the metal strip (4) has at a predetermined distance upstream from the rolling stand (1), a respective control variable (C) for at least one actuator (12) associated with the rolling stand (1), and activates the actuator (12) according to the calculated respective control variable (C), characterized in that, before the metal strip (4) is uncoiled, a contour (K) of at least one end side (11) of the still coiled-up coil (3) is made known once to the control device (8) such that the information about the lateral offset (V) of the portions (i) over the whole length of the metal strip (4) is already available to the control device (8) before the metal strip (4) is supplied to the rolling stand (1), and in that the control device (8) calculates the respective lateral offset (V) utilizing the contour (K).

2. Operating method according to Claim 1, characterized in that the contour (K) of the end side (11) is captured by means of a capture device (13) associated with the uncoiler (2), whilst the coil (3) is already situated in the uncoiler (2), and then supplied to the control device (8).

3. Operating method according to Claim 1 or 2, characterized - in that the contour (K) of the end side (11) of the coil (3) is made known to the control device (8) in the form of a contour line (KL) running from in to out radially, relative to the end side (11) of the coil (3), and in that the control device (8) calculates the respective lateral offset (V) utilizing the contour line (KL), or - in that the contour (K) of the end side (11) of the coil (3) is made known to the control device (8) in the form of a two-dimensional contour surface (KF) relative to the end side (11) of the coil (3), in that the control device (8) calculates on the basis of the contour surface (KF) a contour line (KL) running from in to out radially, relative to the end side (11) of the coil (3), and in that the control device (8) calculates the respective lateral offset (V) utilizing the contour line (KL) but not the two-dimensional contour surface (KF) per se.

4. Operating method according to Claim 1, 2 or 3, characterized in that the metal strip (4) is cold or hot rolled in the rolling stand (1).

5. Control program for a control device (8) of a rolling stand (1) for rolling a metal strip (4), wherein the control program comprises machine code (10) which can be processed by the control device (8), wherein the processing of the machine code (10) by the control device (8) ensures - that before the metal strip (4) is uncoiled by an uncoiler (2) arranged upstream from the rolling stand (1), a contour (K) of at least one end side (11) of the still coiled-up coil (3) is made known once to the control device (8) such that the information about a lateral offset (V) that portions (i) of the metal strip (4) have at a predetermined distance upstream from the rolling stand (1) over the whole length of the metal strip (4) is available to the control device (8), - that the control device (8) calculates the respective lateral offset (V) utilizing the contour (K) for the portions (i), and - that the control device (8) calculates a respective control variable (C), utilizing the respective lateral offset (V) for at least one actuator (12) associated with the rolling stand (1), and activates the actuator (12) according to the calculated respective control variable (C).

6. Control program according to Claim 5, characterized in that the processing of the machine code (10) by the control device (8) ensures that the control device (8) receives the contour (K) of the end side (11) from a capture device (13) associated with the uncoiler (2) whilst the coil (3) is already situated in the uncoiler (2).

7. Control program according to Claim 5 or 6, characterized in that the processing of the machine code (10) by the control device (8) ensures - that the control device (8) receives the contour (K) of the end side (11) of the coil (3) in the form of a contour line (KL) running from in to out radially, relative to the end side (11) of the coil (3), and calculates the respective lateral offset (V) utilizing the contour line (KL), or - that the control device (8) receives the contour (K) of the end side (11) of the coil (3) in the form of a two-dimensional contour surface (KF), relative to the end side (11) of the coil (3), and calculates on the basis of the contour surface (KF) a contour line (KL) running from in to out radially, relative to the end side (11) of the coil (3), and calculates the respective lateral offset (V) utilizing the contour line (KL) but not the two-dimensional contour surface (KF).

8. Control device for a rolling stand (1) of a rolling mill, wherein the control device is programmed with a control program (9) according to Claim 5, 6 or 7 such that the control device executes the control program (9) during operation.

9. Rolling mill which has at least one rolling stand (1), an uncoiler (2) arranged upstream from the rolling stand (1), and a control device (8) for the rolling stand (1), characterized in that the control device (8) takes the form of a control device according to Claim 8.

10. Rolling mill according to Claim 9, characterized in that associated with the uncoiler (2) is a capture device (13) by means of which the contour (K) of the end side (11) is captured whilst the coil (3) is already situated in the uncoiler (2) and then supplied to the control device (8).

11. Rolling mill according to Claim 9 or 10, characterized in that the rolling stand (1) takes the form of a hot rolling stand, in particular the rolling mill takes the form of a Steckel mill, or in that the rolling stand (1) takes the form of a cold rolling stand, in particular a foremost rolling stand of a multi-stand tandem rolling train.