EP2200763B1 - Adaption of a controller in a rolling mill based on the variation of an actual value of a roll product - Google Patents

Description

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

The present invention further relates to an operating program comprising machine code, the processing of which, 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 quantities from the desired quantities to inhomogeneous material properties or interventions of an automation device be led back into 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.

• im Falle eines bandförmigen Walzguts dessen Dicke, in geringem Umfang dessen Breite sowie die Planheit des Walzguts,
• im Falle eines stabförmigen Walzguts dessen Höhe und Breite, manchmal auch das Verhältnis von Höhe und Breite (Höhe und Breite sind hierbei orthogonal zueinander orientiert),
• unabhängig vom Querschnitt des Walzguts der im Walzgut herrschende Zug sowie die Gefügeeigenschaften. Insbesondere bestimmt das Gefüge die späteren Verarbeitungsmöglichkeiten, beispielsweise die Tiefziehfähigkeit von Blech. Das Gefüge wird besonders stark durch die thermische Behandlung in der Kühlstrecke beeinflusst.

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 its height and width, sometimes also 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 train prevailing in the rolling stock 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. The basic automation in particular comprises individual regulations, for example for a rotational speed of a drive motor of a rolling stand or a lifting height of a loop lifter, by means of which the train is set to a desired tension. The technological regulations include superimposed controllers. You determine the target 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 course of coolant quantity applied to a specific point of the rolling stock shall be. In the prior art, both the controller of the basic automation and the controller 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 PT1 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 is to minimize the disturbances in the process behavior caused by leadership interventions and disturbances and the resulting fluctuations in the material properties after passing through the rolling mill. In many cases, 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 on the instantaneous state of the rolling stock to be processed or a current throughput 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. Exemplary is on the DE 103 27 663 A1 directed.

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 having 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 connected to a rolling mill detection device that 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 controlled by means of a regulator. 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, the actual size of the rolling stock after processing by the processing device and a corresponding actual size of the rolling stock are fed to a determination device connected to the rolling mill before being processed 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 means 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 determining device determines the controller 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 rolling be formed of a strip-shaped or a 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.

FIG 1

schematisch ein Walzwerk,

FIG 2

schematisch eine mögliche alternative Ausgestaltung des Walzwerks von FIG 1 und

FIG 3 und 4

zwei Ablaufdiagramme.

Further advantages and details will become apparent from the following description of exemplary embodiments in conjunction with the drawings. In a schematic representation:

FIG. 1

schematically a rolling mill,

FIG. 2

schematically a possible alternative embodiment of the rolling mill of FIG. 1 and

3 and 4

two flowcharts.

FIG. 1 schematically shows a rolling mill. The rolling mill has at least one rolling train 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 is rolled in the rolling mill - regardless of the material of the rolling stock 2 - a strip-shaped rolling stock 2. However, this is not mandatory. Alternatively - see FIG. 2 - The rolling stock 2 may be formed 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 the rolling stock 2 thus usually corresponds to a rolling process. In individual cases, however, 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 disk 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 determining device 8 causes the detecting device 8 performs an operating method in the operation of the rolling mill, which will be described below in connection with the FIG. 1 and 3 is explained in more detail.

The determination device 8 accepts an actual variable x of the rolling stock 2 in a step S1. The actual variable x is detected here by means of a suitable detection device 12 at a location downstream of the processing device 6. The actual size x of the rolling stock 2 is thus an 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'.

• Eine Abmessung des Walzguts 2 quer zu einer Laufrichtung des Walzguts 2. Bei bandförmigem Walzgut 2 kann es sich hierbei um die Dicke (Regelfall) oder die Breite (Ausnahme) des Walzguts 2 handeln. Bei stabförmigem Walzgut 2 kommen als Istgröße x alternativ oder zusammen die Höhe und die hierzu orthogonale Breite des Walzguts 2 in Frage. Bei stabförmigem Walzgut 2 kommt als Istgröße x weiterhin das Verhältnis von Höhe zu Breite in Frage.
• Alternativ zu einer Abmessung des Walzguts 2 kann es sich bei der Istgröße x um einen im Walzgut 2 herrschenden Zug, eine Gefügeeigenschaft oder (im Falle eines bandförmigen Walzguts 2) eine Bandplanheit handeln.

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 rolling stock 2. In the case of strip-shaped rolling stock 2, this can be the thickness (standard case) or the width (exception) of the rolled stock 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 may 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 variable 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 variable 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 explanations regarding 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 variables x, x ', which are used to determine the regulator characteristic R, locally correspond to one another, ie to the same section of the rolling stock 2 (purely by way of example: the first 20% of the rolling stock 2).

In FIG. 3 already a special embodiment of the present operation of the detection device 8 is shown. According to FIG. 3 determines the determination device 8 first in the context of step S5 based on the temporal After processing by the processing device 6, the actual size x of the rolling stock 2 is scattered by the actual size x of the rolled stock 2 after being processed by the processing device 6. The determining device 8 determines in an analogous manner the time course of the corresponding actual size x 'before the processing of the Rolling material 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 * supplied to the controller 7 accordingly.

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

According to FIG. 4 takes the controller 7 in steps S11 and S12 the target size x * and the actual size x of the rolling stock 2 after processing by the processing device 6 opposite. 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 such that it controls the processing device 6 on the one hand stable and on the other hand time-optimized.

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 manipulated variable y is a reference strip, with which the rolling 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 (10)

1. Operating method for a determining device (8) attached to a rolling mill,

   - in which during operation of the rolling mill

   -- a rolling stock (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),

   -- the controller (7) is fed a setpoint variable (x*) and an actual variable (x) of the rolling stock (2) after the machining by the machining device (6),

   -- the controller (7) uses the setpoint variable (x*) and the actual variable (x) in conjunction with a controller characteristic (R) to determine a manipulated variable (y) for the machining device (6),

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

   -- the machining device (6) machines the rolling stock (2) in accordance with the manipulated variable (y) output to said machining device,

   - in which the determining device (8) accepts the actual variable (x) of the rolling stock (2) after the machining by the machining device (6), and accepts a corresponding actual variable (x') of the rolling stock (2) before the machining by the machining device (6), and

   - in which the determining device (8) uses the time profiles of the actual variables (x, x') fed to it in order dynamically to determine the controller characteristic (R) in such a way that the variance of the actual variable (x) of the rolling stock (2) after the machining by the machining device (6) exhibits at least a tendency to minimization, and parameterizes the controller (7) in accordance with the controller characteristic (R) determined by said determining device.
2. Operating method according to Claim 1, characterized in that the determining device (8) uses the time profile of the actual variable (x) of the rolling stock (2) after the machining by the machining device (6)
   to determine a variance of the actual variable (x) of the rolling stock (2) after the machining by the machining device (6), and uses the time profile of the corresponding actual variable (x') before the machining of the rolling stock (2) by the machining device (6) to determine a variance of the corresponding actual variable (x') of the rolling stock (2) before the machining by the machining device (6), and in that the determining device (8) determines the controller characteristic (R) with the aid of the variances determined by said determining device.
3. Operating method according to Claim 1 or 2,
   characterized in that the actual variable (x) of the rolling stock (2) is a dimension of the rolling stock (2) transverse to a running direction of the rolling stock (2), a tension, a microstructural property, in the case of a strip-shaped rolling stock (2), a strip flatness, or in the case of a bar-shaped rolling stock (2) a ratio between two mutually orthogonal dimensions of the rolling stock (2) transverse to the running direction of the rolling stock (2).
4. Operating program that comprises machine code (11), the effect of whose execution by a determining device (8) attached to a rolling mill is that the determining device (8) executes an operating method according to Claim 1, 2 or 3.
5. Data medium on which an operating program (9) according to Claim 4 is stored in machine-readable form.
6. Determining device attached to a rolling mill, the determining device being programmed with an operating program (9) according to Claim 4.
7. Rolling mill,

   - in which the rolling mill has a machining device (6) by means of which a rolling stock (2) running through the rolling mill is machined,

   - in which the rolling mill has a controller (7), which is fed a setpoint variable (x*) and an actual variable (x) of the rolling stock (2)
   after the machining by the machining device (6),

   - in which the controller (7) uses the setpoint variable (x*) and the actual variable (x) in conjunction with a controller characteristic (R) to determine a manipulated variable (y) for the machining device (6),

   - in which the controller (7) outputs the manipulated variable (y) to the machining device (6), and the machining device (6) machines the rolling stock (2) in accordance with the manipulated variable (y) output to it, and

   - in which attached to the rolling mill is a determining device (8) according to Claim 6 that is operated in accordance with 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 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 bar-shaped rolling stock (2).
10. Rolling mill according to Claim 7, 8 or 9, characterized in that the manipulated variable (y) is a desired tension, a desired adjustment or a desired roll gap of a rolling stand, a desired rolling force or a desired thermal influence of the rolling stock (2).

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