EP2477763A1

EP2477763A1 - Cold rolling train featuring mass flow rate regulation on a roll stand

Info

Publication number: EP2477763A1
Application number: EP10754464A
Authority: EP
Inventors: Hans-Joachim Felkl
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2009-09-17
Filing date: 2010-09-10
Publication date: 2012-07-25
Anticipated expiration: 2030-09-10
Also published as: CN102481608A; RU2012111278A; WO2011032888A1; EP2477763B1; BR112012006033A2; PL2477763T3; RU2518831C2; CN102481608B; EP2298461A1

Abstract

A cold rolling train comprises multiple roll stands, through which a cold rolled strip (1) successively runs. An actual speed (v) at which the cold rolled strip (1) is discharged from one (2-1) of the roll stands (2) is measured. The measured actual speed (v) is compared to a corresponding desired speed (v*). A desired value (vU*) for a circumferential roll speed (vU) of the respective roll stand (2-1) is adjusted on the basis of the comparison such that the actual speed (v) matches the desired speed (v*). The respective roll stand (2-1) is controlled according to the adjusted desired value (vU*) for the circumferential roll speed (vU) of the respective roll stand (2-1). Furthermore, a thickness (d) at which the cold rolled strip (1) is discharged from the respective roll stand (2-1) is detected. A nip (s) of the respective roll stand (2-1) is adjusted on the basis of at least the detected thickness (d) of the strip in such a way that the product of the actual speed (v) of the cold rolled strip (1) and the thickness (d) of the strip (d) corresponds to a desired mass flow rate (M*).

Description

description

The present invention relates to a control method for a cold rolling mill which has a plurality of rolling stands which have passed through a cold strip in succession, wherein an actual speed is detected by measurement, with which the cold strip runs out of one of the rolling stands, wherein a strip thickness is still detected. with which the cold strip from the respective rolling mill runs out.

The present invention further relates to a control device for a cold rolling mill, which has a plurality of rolling mills passed through in succession by a cold strip, wherein the control device is supplied with a metrologically detected actual speed with which the cold strip runs out of one of the rolling mills, wherein the control device further comprises a metrologically detected strip thickness with that

Cold strip from the respective rolling mill runs out, is supplied.

The present invention further relates to a computer program having machine code which is directly executable by a control device of a multi-stand cold rolling mill and whose execution by the control means causes the control means to control the cold rolling mill according to a control method of the type described in the opening paragraph.

Finally, the present invention relates to a cold rolling mill,

wherein the cold rolling mill has a plurality of rolling stands, which have passed through a cold strip in succession,

- The cold rolling mill has a speed detecting device which is arranged downstream of one of the rolling stands and by means of which a measuring device Actual speed is detected, with which the cold strip runs out of one of the rolling stands,

- Wherein the cold rolling train has a thickness detection device, which is arranged downstream of the respective rolling stand and by means of which a strip thickness is detected, with the

Cold strip from the respective rolling mill runs out,

- The cold rolling mill having a control device of the type described above, so that the cold rolling mill is operated according to a control method of the type described above.

The abovementioned objects are known, for example, from WO 2009/095323 A1. In WO 2009/095323 AI, the strip thicknesses in front of and behind the first rolling stand of the cold rolling mill and the actual speed of the cold strip behind the first rolling stand of the cold rolling mill are recorded. On the basis of these variables, the setpoint value for the roll circumferential speed of the first roll stand is tracked such that the mass flow through the first roll stand corresponds to a desired mass flow. At the same time, based on the strip thickness and the strip speed in front of the first rolling stand of the cold rolling train, a strip feeding device (for example a reel or an S-roll set) upstream of the first rolling stand is likewise regulated to the desired mass flow. The teaching of WO 2009/095323 AI is based on the principle of the cold strip in front of the first mill stand of the cold rolling mill to impress the desired mass flow over the tape feeder and the strip thickness behind the first stand of the cold rolling mill indirectly over the

Set the actual speed of the cold strip behind the first roll stand of the cold rolling mill.

The approach known from WO 2009/095323 A1 leads to good results if the tape feed device can be controlled in such a way that it actively influences the mass flow ("can impress the desired mass flow") - Although it can passively follow a changed mass flow, it can not actively set the mass flow itself. An example of such a cold rolling train is a cold rolling train in which the belt feed device operates in tension-controlled operation, ie adjusts the mass flow according to the tension prevailing between the strip feed device and the first rolling stand of the cold rolling train in the cold strip. The object of the present invention is to provide possibilities by means of which the mass flow can be set precisely in a simple manner even if the band feeding device arranged upstream of the first rolling stand can not actively set the mass flow.

The object is procedurally achieved by a control method having the features of claim 1. Advantageous embodiments of the control method according to the invention are the subject of the dependent claims 2 to 5.

According to the invention - in addition to the features mentioned above - provided

- That the detected actual speed is compared with a corresponding desired speed and based on the comparison, a target value for a circumferential roller speed of the respective rolling mill is tracked, so that the actual speed is adjusted to the target speed,

- That the relevant rolling mill is controlled according to the tracked setpoint for the peripheral roll speed of the respective rolling mill and

- That a roll gap of the respective rolling mill is tracked based on at least the detected strip thickness such that the product of the actual speed of the cold strip and strip thickness corresponds to a desired mass flow.

In a preferred embodiment of the control method according to the invention, it is provided that the desired value for the whale zenumfangsgeschwindigkeit of the respective rolling stand on the basis of the target speed and a model-based determined lead is determined and that the tracking of the target value for the roller peripheral speed of the respective rolling mill is realized by the model, by means of which the lead is determined, adapted by comparing the actual speed with the target speed becomes. By means of this embodiment, it can be achieved, in particular, that in the event that the detection of the

Actual speed is disturbed, an emergency operation can be maintained. Because in this case, only the adaptation of the model, by means of which the overfeed is determined, must be interrupted. Of the three sizes actual speed of the cold strip, strip thickness and mass flow, one of the sizes is redundant, since the product of the actual speed and the strip thickness corresponds to the mass flow. Due to the fact that the actual speed is controlled directly in the context of the present invention, it is therefore possible that the rolling gap of the respective rolling stand is tracked exclusively on the basis of the detected strip thickness. In general, however, it leads to better results when the nip of the respective rolling mill is tracked by the product of the actual speed of the cold strip and strip thickness.

The control method according to the invention can in principle be used in any of the rolling stands of the cold rolling mill. It is also possible to use the control method according to the invention simultaneously with several rolling stands of the cold rolling mill. It is preferred that at least the rolling mill of the cold rolling train, which is first passed through by the cold strip, is regulated in accordance with the invention. The object is also achieved by a device with the features of claim 6. Advantageous embodiments of the control device according to the invention are the subject of the dependent claims 7 to 10. According to the invention it is provided that the control device - in addition to the features mentioned above -

- compares the actual speed supplied to it with a corresponding set speed and, on the basis of the comparison, tracks a setpoint value for a roller peripheral speed of the relevant rolling stand, so that the actual speed is adjusted to the set speed,

- The relevant rolling stand according to the tracking nominal value for the roller circumferential speed of the respective rolling stand controls and

- A nip of the respective rolling mill based on at least the tape thickness fed to it nachzuführen such that the product of actual speed of the cold strip and strip thickness corresponds to a desired mass flow.

The advantageous embodiments of the control device correspond in content to those of the control method. In addition, the control device can be designed as a software programmable control device.

The object is further achieved by a computer program of the type mentioned above, whose execution by the control device causes the control device controls the cold rolling train according to a control method according to the invention. The computer program can be stored on a data carrier in machine-readable form.

Finally, the object is achieved by a cold rolling train in which - in addition to the features mentioned above - the control device is designed in accordance with the invention, so that the cold rolling train is operated according to a control method according to the invention. Further advantages and details will become apparent from the following description of exemplary embodiments in conjunction with the drawings. In a schematic representation: 1 shows schematically a cold rolling mill,

2 shows a possible embodiment of the speed regulator and

3 shows a preferred embodiment of a roll gap control.

According to FIG. 1, a cold rolling mill for rolling a cold strip 1 has a plurality of rolling stands 2. The rolling stands 2 are passed through by the cold strip 1 in succession.

As far as below generally speaking only of the rolling stands 2 of the cold rolling mill, only the reference numeral 2 itself is used for the rolling stands 2. Partially, however, the reference numeral 2 - separated by a hyphen - a digit or letter n readjusted. In this case, "2-1" denotes the rolling mill 1 first passed through by the cold-rolled strip 1, "2-2" the rolling mill etc. next passed by the cold-rolled strip 1, etc. "2-n" denotes the rolling mill stand of the cold rolling line last passed by the cold strip 1 For reasons of brevity, the corresponding rolling mills 2-1, 2-2, etc. will be referred to below as the first rolling stand, second rolling stand, etc. up to and including the last rolling mill, the cold rolling line being preceded by a strip feeding device 3 via which the cold strip 1 passes to the first rolling stand 2 1, at least one of the rolling stands 2-according to the illustration of FIG 1 to the first rolling stand 2-1-is followed by a speed detection device 4. By means of the speed detection device 4 metrologically detected an actual speed v, with the cold strip 1 from the Geschwindigkeitse upstream 4 upstream

Roll stand 2 (here: the first roll stand 2-1) expires. The detected actual speed v is - with the exception of unavoidable measuring errors - directly with the actual speed the cold strip 1 identical. In particular, the actual velocity v is not a circumferential roll speed vU of the upstream roll stand 2, that is to say a size that is linked to the actual speed of the cold strip 1 only via an overfeed. Also, it is not a roller peripheral speed vU 'of a downstream roll stand 2, as shown in FIG 1 of the roll stand 2-2. The design of the speed detection device 4 can take place as needed. For example, according to the illustration of FIG. 1, a roller can be placed against the cold strip 1, which moves along with the cold strip 1 and its rotational speed is detected, for example by means of a pulse generator. Optical measuring methods, in particular laser measuring methods, are also known.

The same rolling mill 2-1 is further downstream of a thickness detection device 5. By means of the thickness detection device 5, a strip thickness d is metrologically detected, with which the cold strip 1 from the thickness of the detection device 5 upstream rolling stand 2 (here: the first rolling stand 2-1) expires. The detection of the actual speed v is possible virtually without delay. The exact arrangement of the speed detection device 4 is therefore of secondary importance. The detection of the strip thickness d, however, can only be delayed, since the strip thickness d can be detected only locally at the location of the Dickenerfas- device 5 and passes from the expiry of the cold strip 1 from the upstream rolling stand 2-1 until reaching the thickness detection device 5, a transport time. Preferably, therefore, the thickness detection device 5 is arranged as close as possible to the upstream rolling stand 2-1 in order to keep the transport time as low as possible and therefore to achieve the highest possible dynamics. The detected actual speed v and the detected strip thickness d are fed to a control device 6 of the cold rolling train. The control device 6 evaluates the actual speed v supplied to it and the strip thickness d supplied to it and controls the respective rolling stand 2-according to the embodiment of FIG. 1, the first rolling stand 2-1-correspondingly. This is done as follows:

The control device 6 compares the detected

Actual speed v of the cold strip 1 with a corresponding desired speed v *, that is, with the speed at which the cold strip 1 is to run out of the upstream rolling stand 2-1. Based on the comparison, the control device 6 performs a desired value vU * for the circumferential roll speed vU of the respective rolling stand 2-1, so that the actual speed v of the cold strip 1 is adjusted to the desired speed v *. Corresponding to the tracked nominal value vU * for the circumferential roller speed vU, the control device 6 controls the respective rolling stand 2-1.

In order to track the setpoint value vU * for the circumferential roll speed vU, the control device 6 can, in the simplest case, implement an underlying controller structure as shown in FIG.

On the basis of the difference between the actual speed v of the cold strip 1 and the corresponding set speed v *, the controller determines the setpoint value vU * for the roller circumferential speed vU; an inner controller regulates the roller circumferential speed vU based on the difference of the setpoint value vU * for the roller peripheral speed vU and the roller peripheral speed vU itself. Preferably, however, the procedure is different. The preferred procedure is explained in more detail below in conjunction with FIG.

According to FIG 2, a roll gap model 7 is present, by means of which a lead a is determined on the basis of framework and strip sizes, that is to say a factor which determines the setpoint speed v * of the cold-rolled strip 1 and the setpoint value vU * for the circumferential roll speed vU are related to one another: a = v * / vU *

The reciprocal of the overfeed a is fed to a multiplier 8, which determines the corresponding desired value vU * for the circumferential roll speed vU on the basis of the setpoint speed v * of the cold strip 1.

According to FIG. 2, a correction factor k is determined on the basis of which the setpoint velocity v * and actual velocity v of the cold strip 1 are compared-in particular on the basis of the difference - by means of which the roll gap model 7 is adapted. Due to the adaptation of the roll gap model 7, the overfeed a determined by the roll gap model 7 changes (inter alia). The tracking of the setpoint value vU * for the circumferential roll speed vU is therefore implemented indirectly according to FIG. 2, namely by adapting the roll gap model 7 to the setpoint speed v * on the basis of the comparison of the actual velocity v of the cold strip 1.

The control device 6 further performs, by means of a corresponding manipulated variable s *, a rolling gap s of the respective rolling stand 2-1 in such a way that the product of the actual speed v of the cold strip 1 and the strip thickness d corresponds to a desired mass flow M *. It is possible according to the illustration of FIG. 1 that the control device 6 tracks the roll gap s exclusively on the basis of the strip thickness d (and a corresponding desired thickness d *). Because due to the regulation of the actual speed v of the cold strip 1 to the desired speed v * also this type of tracking results in a defined mass flow. However, according to FIG. 3, the product of actual speed v of the cold strip 1 with the strip thickness d is preferably formed in a multiplier 9 and this product (= the actual mass flow) is regulated to the desired mass flow M *. The control device 6 can be implemented in individual cases circuit technology. As a rule, however, the control device 6 is designed as a software programmable control device 6 in accordance with the representation of FIG. This is indicated by the letters "μΡ" (for microprocessor) in FIG 1. In this case, the control device 6 executes a computer program 10 with which the control device 6 is programmed The computer program 10 has machine code 11, which is shown in FIG The execution of the machine code 11 by the control device 6 in this case causes the control device 6 to control the cold rolling train according to the control method explained above.

The computer program 10 can be supplied to the control device 6 in any manner. For example, a supply via a computer-computer connection is possible. Examples of suitable computer-computer connections are a local area network (LAN) and the World Wide Web. Alternatively, it is possible to supply the computer program 10 to the control device 6 via a data carrier 12, on which the computer program 10 is stored in machine-readable form. Examples of suitable data carriers 12 are a CD-ROM, a USB memory stick or an SD memory card. For example, in FIG. 4 the data carrier 12 is designed as a USB memory stick.

The present invention has many advantages. In particular, a defined mass flow and at the same time a correct strip thickness can be achieved in a simple manner. Therefore, it is only necessary for the roll stands 2, which are arranged downstream of the roll stand 2-1 regulated according to the invention, to correctly set the roll peripheral speed vU 'of the respective roll stand 2. This can alternatively take place in that behind the respective rolling stand 2 (for example, the second rolling stand 2-2) by means of a corresponding speed detection device 13, the actual Actual speed is detected and controlled behind this rolling stand 2 or that over a corresponding roll gap model, the respective overfeed is modeled and in this rolling stand 2-2 outlet side desired belt speed is converted into the corresponding circumferential roll speed vU '. Behind the last roll stand 2-n, a conventional monitor control for the last fine correction of the final strip thickness (that is, for the strip thickness of the cold strip 1 behind the last roll stand 2-n) may be provided.

The regulation of the mass flow according to the invention shows its advantages not only under static operating conditions, but above all under dynamically changing operating conditions such as, for example, the threading operation, the passage of a weld seam or the changing of the setpoint speed v *. It also results in these operating conditions improved dimensional accuracy of the final strip thickness. Furthermore, the extent of the required adaptation of the roll gap model 7 is a direct indication of the quality of the roll gap model 7. This indication can also be used generally for the optimization of process models for the cold rolling mill. The dynamic of the control is limited - even in dynamic operating conditions - only by the speed of the cruise control. Furthermore, a continuation of the operation of the cold rolling mill is possible even in case of failure of the speed detection.

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

Claims

claims

1. A control method for a cold rolling mill comprising a plurality of rolling stands (2) consecutively passed through a cold strip (1),

wherein an actual speed (v) is detected by measurement, with which the cold strip (1) runs out of one (2-1) of the rolling stands (2),

wherein the detected actual speed (v) is compared with a corresponding set speed (v *) and the comparison is used to track a setpoint value (vU *) for a roller peripheral speed (vU) of the respective rolling stand (2-1), so that the Actual speed (v) is adjusted to the set speed (v *),

- Wherein the respective rolling stand (2-1) is driven in accordance with the tracked setpoint value (vU *) for the roller circumferential speed (vU) of the respective rolling stand (2-1),

- In addition, a strip thickness (d) is detected, with which the cold strip (1) from the respective roll stand (2-1) expires,

wherein a roll gap (s) of the relevant roll stand (2-1) is tracked on the basis of at least the detected strip thickness (d) such that the product of actual speed (v) of the cold strip (1) and strip thickness (d) is a target mass flow (M * ) corresponds.

2. Control method according to claim 1,

characterized in that the desired value (vU *) for the peripheral roll speed (vU) of the respective rolling stand

(2-1) on the basis of the target speed (v *) and a model-based determined lead (a) is determined and that the tracking of the target value (vU *) for the roller peripheral speed (vU) of the respective rolling stand (2-1) realized thereby is that the model (7), by means of which the lead (a) is determined, based on the comparison of

Actual speed (v) with the target speed (v *) is adapted.

3. Control method according to claim 1 or 2,

characterized in that the roll gap (s) of the respective rolling stand (2-1) is tracked exclusively on the basis of the detected strip thickness (d).

4. Control method according to claim 1 or 2,

characterized in that the nip (s) of the respective rolling mill (2-1) based on the product of

Actual speed (v) of the cold strip (1) and strip thickness (d) is tracked.

5. Control method according to one of the above claims,

characterized in that the respective rolling stand (2-1) of the cold strip (1) first traversed rolling mill (2-1) of the cold rolling mill.

6. control device of a cold rolling mill, which has a plurality of cold strip (1) successively traversed rolling stands (2),

- Where the control device detected by a metrology

Actual speed (v), with which the cold strip (1) from one (2-1) of the rolling stands (2) expires, is supplied,

- wherein the control device supplied to it

Actual speed (v) with a corresponding target speed (v *) compares and based on the comparison of a setpoint (vU *) for a circumferential roller speed (vU) of the respective rolling mill (2-1) tracks so that the actual speed (v) to the Set speed (v *) is adjusted,

- Wherein the control device, the respective rolling stand

(2-1) according to the tracking nominal value (vU *) for the circumferential roller speed (vU) of the respective rolling mill (2-1),

- wherein the control device further comprises a metrologically detected strip thickness (d), with which the cold strip (1) from the respective rolling stand (2-1) expires, is supplied,

- wherein the control device a roll gap (s) of the respective rolling mill (2-1) based on at least the fed her ten strip thickness (d) nachzuführen such that the product of actual speed (v) of the cold strip (1) and strip thickness (d) corresponds to a desired mass flow (M *).

7. Control device according to claim 6,

characterized in that the control device determines the desired value (vU *) for the circumferential roller speed (vU) of the respective rolling stand (2-1) on the basis of the desired speed (v *) and a model-based determined lead (a) and that the control device tracking of

Set value (vU *) for the roll peripheral speed (vU) of the respective stand (2-1) realized by the model (7), by means of which the lead (a) is determined by comparing the actual speed (v) with the Target speed (v *) adapted.

8. Control device according to claim 6 or 7,

characterized in that the control means the rolling gap (s) of the respective rolling stand (2-1) exclusively based on the detected strip thickness (d) tracks.

9. Control device according to claim 6 or 7,

characterized in that the control means the rolling gap (s) of the respective rolling stand (2-1) based on the product of actual speed (v) of the cold strip (1) and strip thickness (d) tracks.

10. Control device according to one of claims 6 to 9, characterized in that it is designed as a software programmable control device.

A computer program comprising machine code (11) directly executable by a control means (6) of a multi-stand cold rolling mill, and the execution thereof by the control means (6) causes the control means (6) to drive the cold rolling mill according to a control method according to any one of claims 1 to 5 regulates.

12. Computer program according to claim 11,

characterized in that it is stored on a data carrier (12) in machine-readable form.

13. cold rolling mill,

- wherein the cold rolling mill has a plurality of cold rolled strip (1) successively traversed rolling stands (2),

- Wherein the cold rolling mill has a Geschwindigkeitserfas sungs- device (4), which is a (2-1) downstream of the rolling stands (2) and by means of which a metrological

Actual speed (v) is detected, with which the cold strip (1) from the respective roll stand (2-1) expires,

- Wherein the cold rolling train has a thickness detection device (5), which is the respective rolling stand (2-1) is arranged and by means of which a strip thickness (d) is detected, with which the cold strip (1) from the respective rolling stand (2-1 ) expires,

- The cold rolling mill having a control device (6) according to one of claims 6 to 10, so that the cold rolling mill is operated according to a control method according to one of claims 1 to 5.