EP2200763A1

EP2200763A1 - Adaption of a controller in a rolling mill based on the variation of an actual value of a roll product

Info

Publication number: EP2200763A1
Application number: EP08803763A
Authority: EP
Inventors: Reinhard Meissen; Martin Niemann; Wilfried Tautz; Heinz Wilharm; Dietrich Wohld
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2007-10-24
Filing date: 2008-09-05
Publication date: 2010-06-30
Anticipated expiration: 2028-09-05
Also published as: US20100211209A1; DE102007050891A1; US8255074B2; EP2200763B1; WO2009053144A1

Abstract

During operation of a rolling mill, a rolling product (2) running through the rolling mill is machined by means of a machining device (6). The machining device (6) is controlled by means of a controller (7), to which a target value (x*) and an actual value (x) of the roll product (2) are fed after machining by the machining device (6). The controller (7) determines based on the target value (x*) and the actual value (x), in conjunction with controller characteristic (R), a controlled variable (y) for the machining device (6) and outputs the controlled variable (y) to the machining device (6). The machining device (6) machines the roll product (2) according to the output controlled variable (y). A detection device (8) receives the actual value (x) of the mill product (2) after machining by the machining device (6) and a corresponding actual value (x') of the mill product (2) before machining by the machining device (6). Based on the temporal profiles of the actual values (x, x') that are fed, said device dynamically determines the controller characteristic (R) such that the variance of the actual value (x) of the roll product (2) at least tends to be minimized after machining by the machining device (2). Said device also parameterizes the controller (7) according to the determined control characteristic (R) determined by it.

Description

Adaptation of a controller in a rolling mill based on the scattering of an actual size of a rolling stock

The present invention relates to an operating method for a detecting device connected to a rolling mill.

The present invention furthermore relates to an operating program, which comprises machine code whose execution by means of a determination device connected to a rolling mill causes the determining device to carry out such an operating method. Furthermore, the present invention relates to a data carrier on which such an operating program is stored in machine-readable form. Furthermore, the present invention relates to a connected to a rolling detection device that is programmed with such an operating program. Finally, the present invention relates to a rolling mill.

The aim of every technical process is the production of a product that has certain characteristics. Ideally, the product has exactly the specific properties. In practice, however, the properties of the product may deviate from the desired nominal properties by certain tolerance ranges. Depending on the individual case, the permissible tolerance ranges may be determined by the subsequent use or further processing of the product as such, by more or less arbitrary specifications of the purchaser of the product or by law.

The causes for the deviation of the actual properties (actual values) from the desired properties (nominal values) can have many causes. For example, the manufacturing process may be subject to interference. Also, the deviation of the actual variables from the reference variables can lead to inhomogeneous material properties or interventions of an automation system. be led back into the manufacturing process in the manufacturing process.

The above general explanations also apply in particular to the processing of a rolling stock in a rolling mill. In this case, the machining generally corresponds to rolling of the rolling stock, that is to say a reduction of its cross section in a rolling stand. In exceptional cases, however, other types of treatment come into question, for example, a thermal treatment in a cooling section, which is downstream of a rolling mill.

Examples of desired nominal properties of a rolling stock are

- In the case of a strip-shaped rolling stock whose thickness, to a small extent its width and the flatness of the rolling stock,

- In the case of a rod-shaped rolling stock whose height and width, sometimes the ratio of height and width (height and width are oriented orthogonal to each other here),

- Regardless of the cross section of the rolling stock of the rolling stock prevailing train and the structural properties. In particular, the microstructure determines the later processing options, such as the thermoformability of sheet metal. The microstructure is particularly strongly influenced by the thermal treatment in the cooling section.

Prior art rolling mills have basic automation and technological controls. In particular, the basic automation comprises individual controls, for example for a rotational speed of a drive motor of a rolling stand or a lifting height of a ski lifter, by means of which the tension is set to a desired tension. The technological regulations include superimposed controllers. You determine the basic values for the basic automation. Examples are the determination of a nominal rolling gap, a nominal rolling force, a nominal rolling speed or a time-dependent flow of coolant over a specific point of the rolling stock. should be brought. In the prior art, both the controllers of the basic automation and the controllers of the technological control each have a typical for the respective control task controller, such as a P-controller, a PI controller, a PD controller, a PTL controller, etc. Furthermore, a respective controller characteristic is determined for each controller. The controller characteristic includes, for example in a PI controller whose proportional gain and its integration time constant.

The type of controller and the controller characteristic are as far as possible determined in the prior art in such a way that the respective controller controls as stably and precisely as possible. In particular, the aim is to use the technological regulations to regulate and control the process so that the quality-relevant parameters are kept as well as possible. The aim here is to minimize the disturbances in the process behavior caused by management interventions and disturbances and the resulting fluctuations in the material properties after the rolling mill has passed through. In many

However, it is not possible to determine the controller characteristic in advance in this way. For example, this may be caused by the fact that the currently optimal controller characteristic in each case depends on the respective operating state of the rolling mill, for example, the instantaneous state of the rolling stock to be processed or a current pass speed of the rolling stock through the rolling mill.

In the prior art, it is known to determine dynamically and state-dependent controller parameters in rolling mills and to specify the respectively determined controller parameters to the controller. For example, the roll gap of a roll stand can be controlled by a roll gap controller, the controller being parameterized as a function of the material properties (composition and cross section) as well as the temperature and the rolling stock speed. Furthermore, it is known to dynamically determine controller parameters and adjust the controller accordingly. For example, reference is made to DE 103 27 663 Al.

The object of the present invention is to provide possibilities by means of which the controller adaptation can be further improved.

The object is achieved by an operating method with the features 1, an operating program having the features of claim 4 and a data carrier on which such an operating program is stored in machine-readable form. Furthermore, the object is achieved by a determination device connected to a rolling mill, which is programmed with such an operating program. Finally, the problem is solved by a suitably designed rolling mill. Advantageous embodiments of the operating method are the subject of the dependent claims 2 and 3, advantageous embodiments of the rolling mill subject of the dependent claims 8, 9 and 10.

During operation of a rolling mill, a rolling mill which passes through the rolling mill is machined by means of a machining direction. The processing device is regulated by means of a controller. The controller is supplied with a desired size and an actual size of the rolling stock after being processed by the processing device. The controller determines based on the desired size and the actual size in conjunction with a controller characteristic a manipulated variable for the processing device. The controller outputs the manipulated variable to the processing device. The processing device processes the rolling stock according to the output to it manipulated variable. According to the invention, a determination device connected to the rolling mill is the actual size of the rolling stock after being processed by the machining device and a corresponding actual size of the rolling stock

Walzguts supplied before processing by the processing device. The determination device determines dynamically based on the time profiles of the actual quantities supplied to it the controller characteristic. In this case, the controller characteristic is determined such that the scattering of the actual size of the rolling stock after processing by the processing device is at least tended to be minimized. The determination device configures the controller according to the controller characteristic determined by it.

The dynamic determination of the controller characteristic and the corresponding dynamic parameterization of the controller can alternatively take place in real time or cyclically.

In a preferred embodiment of the present invention determines the determination means based on the time course of the actual size of the rolling stock after processing by the processing device a corresponding dispersion of this actual size and based on the time course of the corresponding actual size before processing the rolling stock by the processing device, a scattering of this actual size. In this case, the determination device determines the regulator characteristic on the basis of the two variations determined by it.

In principle, any directly or indirectly determinable property of the rolling stock comes into consideration as the actual size of the rolling stock. For example, the actual size of the rolling stock may be a dimension of the rolling stock transverse to a running direction of the rolling stock. In the case of strip-shaped rolling stock, in particular the strip thickness can correspond to the actual size. In the case of rod-shaped rolling stock, in particular the height and the width of the rolling stock can correspond to the actual size. In the case of strip-shaped rolling stock, a strip flatness can furthermore correspond with the actual size of the rolling stock, with bar-shaped rolling stock a ratio of height and width to one another. Also structural properties can be the actual size of the rolling stock.

The rolling mill can be designed as a cold rolling mill or as a hot rolling mill for rolling metal (in particular steel). The rolling mill can also be used alternatively as a rolling mill for zen of a band-shaped or rod-shaped rolling stock.

Also for the manipulated variable come - in analogy to the actual size - a variety of sizes in question. In particular, it may be a desired tension, a nominal setting or a nominal rolling gap of a rolling stand, a nominal rolling force or a thermal target influencing of the rolling stock.

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 rolling mill, FIG. 2 schematically shows a possible alternative embodiment of the rolling mill of FIG. 1 and FIGS. 3 and 4 show two flowcharts.

1 shows schematically a rolling mill. The rolling mill has at least one rolling line 1. The rolling train 1 can be designed, for example, as a single-stand or multi-stand roughing train or as a single-stand or multi-stand finishing train. In both cases, a strip-shaped rolling stock 2 is rolled in the rolling train 1. In the case of training as a finishing train of the rolling mill 1 may be arranged downstream of a cooling section 3, which is also considered in the context of the present invention as part of the rolling mill.

In the case of the design of the rolling mill 1 as a roughing or finishing mill, the rolling mill is designed as a hot rolling mill for rolling metal. It may in particular be designed as a hot rolling mill for rolling steel. As an alternative to an embodiment of the rolling mill as a hot rolling mill, however, the rolling mill can be designed as a cold rolling mill for cold rolling of steel. In this case, in the case of a band-shaped rolling stock 2, the rolling train 1 is formed as a tandem road. According to FIG. 1, a strip-shaped rolling stock 2 is rolled in the rolling mill independently of the material of the rolling stock 2. However, this is not mandatory. Alternatively, as shown in FIG. 2, the rolling stock 2 may be designed as a rod-shaped rolling stock 2, for example as a metal wire. In this case, the rolling train can be arranged, for example, downstream of a layer 4, which places the rolled rolling stock 2 into turns 5. Again alternatively, the rolling mill could be designed as a rolling mill for rolling tubular rolling stock (lugs).

The mill has according to FIG 1, a processing device 6, by means of which the rolling stock 2 is processed when it passes through the rolling mill. The processing device 6 is usually designed as a rolling mill 6. The processing of WaIz- good 2 thus usually corresponds to a rolling process. In

However, individual cases, the processing device 6 could also be designed differently. For example, it could be designed as a loop lifter, by means of which the train of the rolling stock 2 is influenced. It could also be formed in individual cases as a cooling section 3, by means of which a temperature influencing of the rolling stock 2 takes place.

The rolling mill also has at least one controller 7. Furthermore, a detection device 8 is attached to the rolling mill (attached). The determination device 8 is designed as a software programmable determination device 8. It is programmed by means of an operating program 9, which is supplied to the detection device 8 by means of a suitable data carrier 10. On the data carrier 10 - for example, a CD-ROM, a USB memory stick or a

Memory card - the operating program 9 is stored in machine-readable form. It comprises machine code 11, which can be processed by the determination device 8. The processing of the machine code 11 by the determination device 8 has the effect that the determination device 8 executes an operating method during operation of the rolling mill, which is explained in more detail below in conjunction with FIGS. 1 and 3. The determination device 8 accepts an actual variable x of the rolling stock 2 in a step S1. In this case, the actual variable x is detected by means of a suitable detection device 12 at a location which is downstream of the processing device 6. The actual size x of the rolling stock 2 is thus one

Actual size x of the rolling stock 2 after being processed by the processing device 6. The detecting device 12 may be arranged directly downstream of the processing device 6. Alternatively, 8 additional processing devices 6 'may be arranged between the processing device 6 and the detection device, for example, further rolling stands 6'.

The actual size x of the rolling stock 2 can alternatively be detected directly or indirectly. For example, it can be one of the following sizes:

- A dimension of the rolling stock 2 transversely to a running direction of the rolled stock 2. In strip-shaped rolling 2 this may be the thickness (rule) or the width (exception) of the rolled material 2. In the case of rod-shaped rolling stock 2, the height and the width of the rolling stock 2 orthogonal thereto may alternatively or jointly be considered as the actual size x. In the case of rod-shaped rolling stock 2, the ratio of height to width is also considered as the actual size x.

As an alternative to a dimension of the rolling stock 2, the actual size x can be a tension prevailing in the rolling stock 2, a structural property or (in the case of a strip-shaped rolling stock 2) a strip flatness.

In a step S2, the determination device 8 adds the actual quantity x newly received in step S1 to a temporal sequence of previously accepted actual variables x. It thus updates a time course of the actual variable x. Optionally, in the context of step S2, one (or more) old, "outdated" actual variable x can be removed from the time course. In a step S3, the determination device 8 accepts a further actual variable x '. The further actual variable x 'corresponds in terms of its significance to the actual size x, but it is detected by means of a further detection device 12' at a location of the rolling mill, which lies in front of the processing device 6. The further actual variable x 'is therefore an actual quantity x' before the processing of the rolling stock 2 by the processing device 6. With regard to the arrangement of the further detecting device 12 ', the statements relating to the arrangement of the detecting device 12 apply analogously.

In a step S4, the determination device 8 - analogously to step S2 - updates a time profile of the further actual variable x '.

In steps S5 to S7, the determination device 8 dynamically determines a controller characteristic R on the basis of the time profiles of the actual quantities x, x 'supplied to it. It determines the controller characteristic R in such a way that the dispersion of the actual size x of the rolling stock 2 after processing by the processing device 6 is minimized (at least with a tendency). As a rule, a gradual tracking should be sought. The determination device 8 finally parameterizes the controller 7 in a step S8 in accordance with the controller characteristic R. determined by it.

The above-described detection of the actual variables x, x 'ann (but does not have to) take place simultaneously. However, it is important that the temporal courses of the actual quantities x, x ', which are used to determine the regulator characteristic R, locally correspond to one another, ie to the same section of the rolled stock 2 (purely by way of example: the first 20% of the rolled stock 2) are.

FIG. 3 already shows a specific embodiment of the present mode of operation of the determination device 8. According to FIG. 3, the determination device 8 first determines in the context of the step S5 on the basis of the time After processing by the processing device 6, the actual size x of the rolling stock 2 is spread over the actual size x of the rolled stock 2 after being processed by the processing device 6. The determining device 8 determines the time course of the corresponding actual variable x 'in an analogous manner Processing of the rolling stock 2 by the processing device 6, a scattering of the actual size x 'of the rolling stock 2 before processing the rolling stock 2 by the processing device 6. In step S7, the determining means 8 then determines the controller characteristic R on the basis of the two determined by her scatters.

According to the invention, the mean value of the detected actual variables x and / or x 'is not included in the determination of the controller characteristic R. In particular, a possible deviation of the mean value of the actual size x of the rolling stock 2 after being processed by the processing device 6 can be corrected by adjusting a setpoint quantity x * fed to the controller 7 accordingly.

The controller 7 executes a control method during operation of the rolling mill, which is explained in more detail below in conjunction with FIGS. 1 and 4.

According to FIG 4, the controller 7 takes in steps Sil and S12 the

Target size x * and the actual size x of the rolling stock 2 after processing by the processing device 6 against. The controller 7 uses the setpoint variable x * and the actual variable x in conjunction with the controller characteristic R to determine a manipulated variable y for the processing device 6. The manipulated variable y is output to the processing device 6 in a step S14. The controller 7 thus controls the processing device 6 in such a way that the processing device 6 processes the rolling stock 2 in accordance with the manipulated variable y output to it.

The manipulated variable y can be of a varied nature. For example, the manipulated variable y may be a desired tension, a nominal position or a nominal rolling gap of a rolling stand, a Sollwalzkraft or a thermal target influencing of the rolling stock 2 act.

The embodiment according to the invention has many advantages. In particular, the determination of the controller characteristic R takes place in such a way that the largest possible percentage of the rolling stock 2 passing through the rolling mill lies within the permissible tolerance range. Furthermore, the controller 7 is adapted in such a way that it controls the processing device 6 on the one hand stably and on the other hand optimally in terms of time.

The embodiments according to the invention are to be used as needed. In practice, it has proven to be of particular importance if the actual quantities x, x 'are the strip thickness of a strip-shaped rolling stock 2 and the correcting variable y is a reference strip, with which the rolled stock 2 is subjected during rolling. However, the present invention is not limited to this embodiment.

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. Operating method for a connected to a rolling mill detection device (8), - wherein during operation of the rolling mill

- A rolled material passing through the rolling mill (2) is processed by means of a processing device (6), - The processing device (6) by means of a regulator

(7) is regulated, - the controller (7) a target size (x *) and an actual size (x) of the rolling stock (2) are fed after processing by the processing device (6),

- the controller (7) based on the desired size (x *) and the actual size (x) in conjunction with a controller characteristic (R) determines a manipulated variable (y) for the processing device (6),

- The controller (7) outputs the manipulated variable (y) to the processing device (6) and

the processing device (6) processes the rolling stock (2) in accordance with the manipulated variable (y) output to it,

- wherein the determination device (8) the actual size (x) of the rolling stock (2) after processing by the processing device (6) and a corresponding actual size (x ') of the rolling stock (2) before processing by the processing device (6) receives,

wherein the determination device (8) dynamically determines the controller characteristic (R) on the basis of the time profiles of the actual quantities (x, x ') supplied to it so that the scattering of the actual size (x) of the rolling stock (2) after processing by the Processing device (6) is at least tended to be minimized, and the controller (7) in accordance with the determined by her controller characteristic (R) parameterized.

2. Operating method according to claim 1, characterized in that the determination device (8) on the basis of the time course of the actual size (x) of the rolling stock (2) after being processed by the processing device (6). a scattering of the actual size (x) of the rolling stock (2) after processing by the processing device (6) and on the basis of the time course of the corresponding actual size (x ') before processing the rolling stock (2) by the processing device (6) Scattering of the corresponding actual size (x ') of the rolling stock (2) determined before processing by the processing device (6) and that the determining device (8) determines the controller characteristic (R) on the basis of the scattering determined by it.

3. Operating method according to claim 1 or 2, characterized in that the actual size (x) of the rolling stock (2) a dimension of the rolling stock (2) transversely to a running direction of the rolling stock (2), a train, a structural property, in the case of a band-shaped Rolled material (2) is a band flatness or in the case of a rod-shaped rolling stock (2) is a ratio of two mutually orthogonal dimensions of the rolling stock (2) transversely to the running direction of the rolling stock (2).

An operation program comprising machine code (11) whose execution by a detection means (8) connected to a rolling mill causes the detection means (8) to carry out an operation method according to claim 1, 2 or 3.

5. Disk on which in machine-readable form an operating program (9) is stored according to claim 4.

6. At a rolling mill connected detection device, wherein the detection device is programmed with an operating program (9) according to claim 4.

7. rolling mill,

- wherein the rolling mill has a processing device (6) by means of which a rolling mill passing through the rolling mill (2) is processed,

- Wherein the rolling mill has a regulator (7), which a target size (x *) and an actual size (x) of the rolling stock (2) after be supplied to the processing by the processing device (6),

- wherein the controller (7) based on the desired size (x *) and the actual size (x) in conjunction with a controller characteristic (R) determines a manipulated variable (y) for the processing device (6),

- wherein the controller (7) outputs the manipulated variable (y) to the processing device (6) and the processing device (6) processes the rolling stock (2) in accordance with the manipulated variable (y) delivered to it,

- Wherein a determination device (8) according to claim 6 is connected to the rolling mill, which is operated according to an operating method according to claim 1, 2 or 3.

8. Rolling mill according to claim 7, characterized in that the rolling mill is designed as a cold rolling mill or as a hot rolling mill for rolling metal, in particular of steel.

9. rolling mill according to claim 7 or 8, characterized in that the rolling mill is designed as a rolling mill for rolling a strip-shaped rolling stock (2) or a rodförmi- gene rolling stock (2).

10. Rolling mill according to claim 7, 8 or 9, characterized in that the manipulated variable (y) is a desired train, a nominal setting or a nominal rolling gap of a rolling mill, a nominal rolling force or a thermal target influencing of the rolling stock (2).