Roll stand with comprehensive eccentricity compensation

Abstract

In a rolling stand (1), a flat metal stock is rolled at a rolling speed. A control device of the rolling stand (1) receives a symmetrical target roll gap (s*). The control device receives measured variables (MOS, MDS) determined by measuring devices (6 to 8) and dependent on a symmetrical eccentricity occurring during rolling of the stock in the rolling stand (1) and an asymmetrical eccentricity occurring during rolling of the stock in the rolling stand (1).The control device determines respective setpoints for an operator-side and a drive-side adjustment device of the roll stand (1), by means of which the roll gap is adjusted on the drive side and operator side of the roll stand (1), taking into account the target roll gap (s*), an implicitly or explicitly specified target roll gap wedge (k*), a symmetrical compensation value (δs), and an asymmetrical compensation value (δk), and controls the adjustment devices accordingly. The control device determines the symmetrical compensation value (δs) using the symmetrical measured variable (MS) and the asymmetrical compensation value (δk) using the asymmetrical measured variable (MA).When determining the target values ​​for the adjusting devices, the control device takes into account the target roll gap (s*) and the symmetrical compensation value (δs) with the same sign and the target roll gap wedge (k*) and the asymmetrical compensation value (δk) with the opposite sign.

Description

field of technology

[0001] The present invention is based on an operating method for a control device of a rolling stand in which a flat rolled metal product is rolled at a rolling speed, wherein the control device of the rolling stand receives a symmetrical desired roll gap, wherein the control device receives a measured variable detected by means of a measuring device and dependent on a symmetrical eccentricity occurring in the rolling stand during rolling of the rolled stock, wherein the control device determines respective desired values ​​for an operator-side and a drive-side adjusting device of the rolling stand, by means of which the roll gap is adjusted on the drive side and operator side of the rolling stand, taking into account the desired roll gap and a symmetrical compensation value and controls the adjusting devices accordingly, wherein the control device determines the symmetrical compensation value using the symmetrical measured variable, wherein the control device takes the desired roll gap and the symmetrical compensation value with the same sign into account when determining the desired values ​​for the adjusting devices.

[0002] The present invention further relates to a control program for a software-programmable control device for a rolling stand, wherein the control program comprises machine code which can be directly processed by the control device, wherein the processing of the machine code by the control device causes the control device to carry out such an operating method.

[0003] The present invention further relates to a control device for a rolling stand in which a flat rolled metal product is rolled at a rolling speed, wherein the control device is programmed with such a control program, so that the control device carries out such an operating method.

[0004] The present invention is further based on a rolling stand in which a flat metal rolling stock is rolled at a rolling speed, wherein the rolling stand has an operator-side and a drive-side adjustment device, by means of which the roll gap in which the rolling stock is rolled can be adjusted on the drive side and operator side of the rolling stand, wherein the rolling stand has a measuring device by means of which a measured variable is recorded which is dependent on a symmetrical eccentricity occurring in the rolling stand during rolling of the rolling stock, wherein the measuring device for supplying the measured variable is connected to a control device of the rolling stand and the control device for controlling the adjustment devices is connected to the adjustment devices, wherein the control device is designed as a control device which controls the rolling stand according to such an operating method. State of the art

[0005] The above-mentioned subject matters are generally known. Reference may be made purely by way of example to EP 0 170 016 B1, DE 10 2006 008 574 A1, and EP 0 698 427 A1. Furthermore, reference may be made to DE 10 2019 207 497 A1, EP 0 424 709 A2, and AT 407 015 B. EP 3 419 771 B1, EP 0 407 628 A1, and DE 10 2004 039 829 B3 may also be mentioned in this context.

[0006] A similar procedure is also known from DE 38 44 202 A1. In DE 38 44 202 A1, the rolling forces are recorded separately for the operating and drive sides. The respective eccentricity compensation values ​​are determined separately for the operating and drive sides and taken into account when controlling the adjustment devices. Summary of the invention

[0007] In both cold and hot rolling, the accuracy with which the flat rolled stock is rolled to a desired thickness is an important quality criterion. Therefore, the strip thickness is controlled to the target value within the basic automation system by adjusting the roll gap, the stand speed, the inlet and outlet tensions, and, if necessary, other adjustable parameters.

[0008] Roll eccentricities and out-of-roundness can cause periodic deviations in strip thickness. Such periodic errors cannot be compensated for by conventional thickness control systems. Furthermore, roll eccentricities can cause periodic disturbances in the rolling force and in the tension in the rolled material, particularly in the inlet tension. Such disturbances must be suppressed by other control systems (e.g., an AGC (automatic gage control) or a strip tension control system (e.g., using filters).

[0009] To compensate for such errors, it is known in the state of the art to compensate for the eccentricity (see the above-mentioned documents).

[0010] As long as the roll eccentricity is uniform across the rolling direction (i.e., across the barrel length of the rolls of the rolling stand), the state-of-the-art procedures lead to good results. When applying the teaching of DE 38 44 202 A1, eccentricities are well compensated even when there are deviations between the situation on the operating side and the situation on the drive side. However, the teaching of DE 38 44 202 A1 requires a completely separate procedure for the operating side and the drive side and, above all, is incompatible with the usual compensation of symmetrical eccentricity. The procedure of DE 38 44 202 A1 is therefore often impractical.

[0011] The object of the present invention is to create possibilities by means of which the advantages of the teaching of DE 38 44 202 A1 - i.e. a compensation of eccentricities even when there are deviations between the situation on the operating side and the situation on the drive side - can be achieved, without having to accept the disadvantages of the teaching of DE 38 44 202 A1 - i.e. completely separate procedures for the operating side and the drive side, which are not compatible with the compensation of a symmetrical eccentricity.

[0012] The object is achieved by an operating method having the features of claim 1. Advantageous embodiments of the operating method according to the invention are the subject of dependent claims 2 to 11.

[0013] According to the invention, an operating method of the type mentioned at the outset is designed in that that the control device, in addition to the measured variable dependent on the symmetrical eccentricity, also receives a measured variable dependent on an asymmetrical eccentricity occurring in the roll stand during rolling of the rolling stock, that the control device for the operator-side and a drive-side adjustment device of the roll stand also takes into account an implicitly or explicitly given target roll gap wedge and an asymmetrical compensation value when determining the target values, that the control device determines the asymmetrical compensation value using the asymmetrical measured variable, and that the control device takes into account the target roll gap wedge and the asymmetrical compensation value with opposite signs when determining the target values ​​for the adjustment devices.

[0014] The advantage of the inventive teaching becomes particularly apparent when the inventive teaching is to be retrofitted to a rolling stand that already compensates for symmetrical eccentricity. This is because, within the scope of the inventive teaching, the existing compensation for symmetrical eccentricity can be retained unchanged, so that only the compensation for asymmetrical eccentricity needs to be retrofitted. In DE 38 44 202 A1, a fundamental reimplementation is required.

[0015] The rolling of the rolled stock in the rolling stand can, as in the prior art, alternatively be hot rolling or cold rolling. The rolled stock is usually a strip. In individual cases, however, it can also be heavy plate. The rolled stock is often made of steel. However, it can also be made of another metal, for example, copper, brass, or aluminum. The adjusting devices are usually designed as hydraulic cylinder units. The target roll gap wedge can be explicitly specified. In this case, the target roll gap wedge can alternatively have the value 0 or - for example, when rolling a slit slab - a value other than 0. Alternatively, the target roll gap wedge can be implicitly specified. In this case, the target roll gap wedge usually has the value 0.

[0016] Preferably, separate processing takes place after determining the symmetrical measured variable and the asymmetrical measured variable. Thus, the control device uses the symmetrical measured variable, but not the asymmetrical measured variable, to determine the symmetrical compensation value, and the asymmetrical measured variable, but not the symmetrical measured variable, to determine the asymmetrical compensation value.

[0017] Preferably, the control device determines the setpoint value for the operator-side adjustment device by adding the symmetrical setpoint roll gap, the symmetrical compensation value, half of the setpoint roll gap wedge and half of the asymmetrical compensation value and determines the setpoint value for the drive-side adjustment device by adding the symmetrical setpoint roll gap and the symmetrical compensation value and subtracting half of the setpoint roll gap wedge and half of the asymmetrical compensation value.

[0018] If s* is the symmetrical nominal roll gap, k* the nominal roll gap wedge, δs the symmetrical compensation value and δk the asymmetrical compensation value, the following relationships apply to the nominal value pOS on the operating side and the nominal value pOS on the drive side: pDS = ƒ s ∗ + δ + k ∗ + δk / 2 und pOS = ƒ s ∗ + δ − k ∗ + δk / 2 .

[0019] It is possible for the recorded measured variables to directly include a measured variable that can be used to determine the symmetrical measured variable. This is particularly the case when a variable related to the center of the rolled stock is recorded locally. In many cases, however, it is better and simpler if the control device for the drive side and the operator side of the rolling stand each receives a drive-side or operator-side measured variable and determines the symmetrical measured variable by summing or averaging. In a similar way, the control device can determine the asymmetrical measured variable in this case by taking the difference. This eliminates the need for a recording device compared to a design in which the recorded measured variables directly include a symmetrical measured variable or the like.

[0020] There are various options for determining the compensation values. Preferably, that the control device implements a first and a second observer, each comprising a plant model of the rolling stand, a number of periodic disturbance models and a state feedback, that the control device supplies the first observer with a speed variable characteristic of the rolling speed, the symmetrical target roll gap and the symmetrical measured variable and supplies the second observer with the speed variable, the target roll gap wedge and the asymmetrical measured variable and that the control device determines the symmetrical compensation value by means of the first observer and the asymmetrical compensation value by means of the second observer.

[0021] The speed variable can be the peripheral speed of a roll in the rolling stand. Based on the peripheral speed, in conjunction with the radius or diameter of the corresponding roll, the rotational speed of the respective roll can be easily determined. Alternatively, the speed variable can be the inlet or outlet rolling speed, which, in conjunction with the lead or retardation, can be converted into the peripheral speed of the rolls. The radii or diameters of the rolls can be readily known to the control device. The lead and retardation can also be readily known to the control device. Alternatively, the speed variable can be the rotational speed itself. In this case, no further conversion is necessary.

[0022] The plant models can be implemented in various ways. Currently, it is preferred that the respective plant model comprise three elements connected in series. The front element takes into account the reaction time of the adjustment devices. The middle element takes into account the sensitivity of the measured variable supplied to the respective plant model to the occurring eccentricities. The rear element takes into account the reaction time of the measuring devices. This design is simple, robust, and delivers good results.

[0023] The response time of the control devices can be taken into account in the respective plant model, for example, using a PTn element (where n = 1, 2, etc.). Similarly, the response time of the measuring devices can also be taken into account in the respective plant model, for example, using a PTn element (where n = 1, 2, etc.). As a rule, it is sufficient to model them as PT1 elements (where n = 1). This type of modeling corresponds to a low-pass filter behavior of the respective modeled element.

[0024] The sensitivity is considered as a factor. The factor can be specified as required. For example, in the case where the measured variables are local thicknesses of the rolling stock at the exit side of the rolling stand, the sensitivity can be specified as the inverse of a quotient increased by 1. The quotient contains the spring constant of the rolling stock as the numerator and the spring constant of the rolling stand as the denominator. If the spring constant of the rolling stock is denoted by cm and the spring constant of the rolling stand by cg, the (in this case dimensionless) sensitivity V is thus obtained as V = VH = 1 1 + cm / cg .

[0025] Likewise, in the case where the measured values ​​for rolling are local forces exerted on the rolling stock, the sensitivity can be specified as the product of the spring constant of the rolling stock and the spring constant of the rolling stand divided by the sum of the spring constant of the rolling stock and the spring constant of the rolling stand. In this case, the sensitivity V is given by V = VW = cm ⋅ cg cm + cg .

[0026] In this case, the sensitivity has the dimension N / m.

[0027] Furthermore, if the measured variables are tensions occurring on the inlet or outlet side during rolling of the rolled stock, a value determined during testing can be specified as the sensitivity. In this case, the sensitivity also has the dimension N / m.

[0028] Any DC component determined within the framework of the respective system model can alternatively be compensated by means of a respective integrator or filtered out by means of a high-pass filter arranged downstream of the measuring device.

[0029] Furthermore, the respective plant model can include an additional element, arranged downstream of the previous element, designed as a high-pass filter, particularly a DT1 element. This allows the plant model to model the behavior at low frequencies more accurately. In particular, the influence of external controls at low frequencies can be simulated.

[0030] The plant model can be universal. It can therefore be used regardless of which of the above-mentioned variables (thickness, tension, rolling forces) are recorded as measured variables. It is only necessary to determine the type of measured variables during commissioning and to parameterize the plant models accordingly (e.g., the time constants for the two PTn elements and the sensitivity value).

[0031] There are also various options for the design of the periodic disturbance models. Preferably, the respective disturbance model comprises a front multiplier, a front integrator, a rear multiplier, and a rear integrator. In this case, the control device the output signal of the rear integrator and an angular frequency of the respective disturbance model to the front multiplier, the output signal of the front multiplier to the front integrator, the output signal of the front integrator and the angular frequency of the respective disturbance model to the rear integrator, the output signal of the rear multiplier to the rear integrator, the output signal of the front integrator to the respective system model and the output signals of both integrators and the angular frequency of the respective disturbance model to a feedback block of the state feedback assigned to the respective disturbance model.

[0032] This design is simple, robust and delivers good results.

[0033] The number of disturbance models for each observer can be determined as required. For example, in a conventional four-high stand comprising two work rolls and two backup rolls, four disturbance models for the fundamental vibration and three harmonics of the respective backup roll can be present for each of the two backup rolls, and two disturbance models for the fundamental vibration and the first harmonic of the work rolls can be present for each of the two work rolls. The assignment of the respective disturbance model to a specific roll and a specific vibration is determined - regardless of the design of the roll stand - by the respective angular frequency. The respective angular frequency ω is determined in a known manner by the relationship ω = 2 ⋅ π ⋅ ƒ , where f is the rotational speed of the respective roller.

[0034] Often the main part of the eccentricity is found in the fundamental vibration of the respective roller, while in the harmonics the amplitude of the eccentricity is significantly lower.

[0035] In the simplest case, the control system adds the output signal of the front integrator to the output signal of the first term of the respective plant model. The output signals of the front integrators are added independently of each other—separately for each observer. As a result, the output signals of the front integrators of the disturbance models of the respective observer are added to the output signal of the first term of the respective observer's plant model.

[0036] Preferably, the feedback block assigned to the respective disturbance model determines a respective component for the respective compensation value by utilizing the angular frequency of the respective disturbance model, the output signal of the front integrator of the respective disturbance model, the output signal of the rear integrator of the respective disturbance model, the reaction time of the adjustment devices, and a resulting delay time. This allows for the compensation of a phase shift resulting from the unavoidable delay times. Here, too, processing is performed separately for the individual disturbance models. The output signals of the feedback blocks are added – separately for the two observers.

[0037] The compensation of the phase shift is particularly simple and provides particularly good results if the feedback block assigned to the respective disturbance model based on the relationships z 1 ′ = z 1 + ω ⋅ z 2 ⋅ TPC und z 2 ′ = z 2 − ω ⋅ z 1 ⋅ TPC a first and second modified output signal is determined, where z1' is the first modified output signal, z1 is the output signal of the front integrator, ω is the respective angular frequency, z2 is the output signal of the rear integrator, TPC is the reaction time of the adjusting devices and z2' is the second modified output signal, and based on the relationship z = z 1 ′ ⋅ cos ω ⋅ TG − z 2 ′ ⋅ sin ω ⋅ TG the respective share for the respective compensation value is determined, where z is the respective share for the respective compensation value and TG is the resulting delay time.

[0038] The delay time can have a relatively small or a relatively large value. The delay time has a relatively small value if the measured variables for rolling are forces exerted on the rolled stock or tensions occurring during rolling of the rolled stock. In this case, the resulting delay time can be set equal to the response time of the measuring devices. If, on the other hand, the measured variables are thicknesses of the rolled stock at the outlet side of the roll stand, in addition to the response time of the measuring devices, a transport time must also be taken into account which elapses for conveying a certain section of the rolled stock from the roll stand to the measuring devices. In this case, the resulting delay time is the sum of the response time of the measuring devices and the transport time.The transport time is essentially determined by the speed of the rolling stock at the exit side of the rolling stand and the distance of the measuring devices from the rolling stand.

[0039] The object is further achieved by a control program having the features of claim 12. According to the invention, the execution of the control program causes the control device to execute an operating method according to the invention.

[0040] The object is further achieved by a control device having the features of claim 13. According to the invention, the control device is programmed with a control program according to the invention, so that the control device executes an operating method according to the invention.

[0041] The object is further achieved by a rolling stand having the features of claim 14. According to the invention, a rolling stand of the type mentioned at the outset is designed in that that the rolling stand, in addition to the measuring device, has a further measuring device by means of which a further measured variable is recorded which is dependent on an asymmetric eccentricity occurring in the rolling stand during rolling of the rolling stock, that the further measuring device is also connected to a control device of the rolling stand for supplying the further measured variable and that the control device is designed as a control device according to the invention which controls the rolling stand according to an operating method according to the invention. Short description of the drawings

[0042] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of an embodiment, which is explained in more detail in conjunction with the drawings. FIG 1 a rolling arrangement, FIG 2 a rolling stand from above, FIG 3 a section through a rolling stand, FIG 4 a perspective view of a rolling stand, FIG 5 a control scheme, FIG 6 a flow chart, FIG 7 a determination method for measured variables, FIG 8 an embodiment of the control scheme of FIG 5 , FIG 9 a disturbance model and FIG 10 a feedback block. Description of the embodiments

[0043] According to FIG 1 In a rolling stand 1, a rolling stock 2 is rolled at a rolling speed v. The rolling stock 2 consists of a metal, for example steel. According to the illustrations in the FIG 2 and 3 It is a flat rolled product. The rolling stand 1 has rolls 3, for example, work rolls and backup rolls. However, the rolling stand 1 can also have more or fewer rolls than the number 3 shown.

[0044] The rolling stand 1 has according to FIG 3 an operator-side adjusting device 4 and a drive-side adjusting device 5. The adjusting devices 4, 5 are designed according to the illustrations in the FIG 3 und 4 Typically designed as hydraulic cylinder units. The roll gap can be adjusted on the drive side and operator side of the rolling stand 1 using the adjustment devices 4 and 5. The rolling stock 2 is rolled in the roll gap.

[0045] The rolling stand 1 has according to FIG 1 furthermore, measuring devices 6, 7 or 8 are provided. By means of the measuring devices 6, 7 or 8, measured variables MDS, MOS are recorded, which occur during the rolling of the rolling stock 2. The measured variables MDS, MOS are determined in such a way that they depend on a symmetrical eccentricity occurring during the rolling of the rolling stock 2 in the rolling stand 1 and an asymmetrical eccentricity occurring during the rolling of the rolling stock 2 in the rolling stand 1. Corresponding measured variables MDS, MOS are generally known to those skilled in the art. For example, according to the illustration in FIG 5 The thicknesses of the rolled stock 2 on the exit side of the rolling stand 1 are measured by means of the measuring devices 6. The thicknesses are measured at least on the operator side and the drive side, and optionally additionally in the center. The respective rolling forces can also be measured by means of the measuring devices 7. The rolling forces are usually measured on the operator side and the drive side. Tensions occurring in the rolled stock 2 can also be measured by means of the measuring devices 8. The tensions can be measured on the inlet side or the exit side of the rolling stand 1, with inlet-side detection being preferred. The tensions are measured at least on the operator side and the drive side, and optionally additionally in the center. Other measured variables are also conceivable.

[0046] In the following it is assumed that, as shown in FIG 5 as measured variables MDS, MOS, only one drive-side measured variable MDS and one operator-side measured variable MOS are recorded by the measuring devices 6, 7 or 8.

[0047] The rolling stand 1 is designed according to FIG 1 controlled by a control device 9. The control device 9 is connected to the measuring devices 6, 7, or 8, so that the measuring devices 6, 7, or 8 can feed the recorded measured variables MDS, MOS to the control device 9, and the control device 9 can receive the recorded measured variables MDS, MOS. The control device 9 is also connected to the adjusting devices 4, 5, so that the control device 9 can control the adjusting devices 4, 5.

[0048] The control device 9, as in FIG 1 indicated by the designation "µP" within the control device 9, is designed as a software-programmable control device. The control device 9 is designed according to FIG 1 programmed with a control program 10. The control program 10 comprises machine code 11, which can be directly processed by the control device 9. The programming of the control device 9 with the control program 10 or the processing of the machine code 11 by the control device 9 causes the control device 9 to execute an operating method, which is described below - initially in connection with FIG 6 - is explained in more detail.

[0049] According to FIG 6 In a step S1, the control device 9 receives a symmetrical target roll gap s*. The symmetrical target roll gap s* is a uniform value that is symmetrical across the barrel length of the rolls 3 of the rolling stand 1.

[0050] In a step S2, the control device 9 is informed of a desired roll gap wedge k*. It is as shown in FIG 1 It is possible for the target roll gap wedge k* to be explicitly specified to the control device 9, so that the control device 9 receives the target roll gap wedge k*. Alternatively, an implicit specification is possible, for example, if it is assumed that the target roll gap wedge k* should always have the value 0.

[0051] In a step S3, the control device 9 receives the measured variables MDS, MOS acquired by the measuring devices 6, 7, or 8. As already mentioned, it is assumed here that the measuring devices 6, 7, or 8 only acquire a drive-side measured variable MDS and an operator-side measured variable MOS. Therefore, the control device 9 can only receive these measured variables MDS, MOS in step S3.

[0052] In a step S4, the control device 9 determines a symmetrical measured variable MS and an asymmetrical measured variable MA based on the measured variables MDS, MOS. To determine the symmetrical measured variable MS, the control device 9 determines according to FIG 7 First, the sum of the measured values ​​MDS and MOS is calculated. In some cases, the sum must be divided by 2 to calculate the mean. In other cases, the sum can be used directly. The two options are shown in FIG 7 To determine the asymmetrical measured variable MA, the control device 9 determines FIG 7 the difference between the measured values ​​MDS, MOS.

[0053] In a step S5, the control device 9 then determines a symmetrical compensation value δs using the symmetrical measured variable MS and an asymmetrical compensation value δk using the asymmetrical measured variable MA. When determining the symmetrical compensation value δs, the asymmetrical measured variable MA is not used. Likewise, the symmetrical measured variable MS is not used when determining the asymmetrical compensation value δk. Step S5 will be explained in more detail later.

[0054] Furthermore, in a step S6, the control device 9 determines the setpoints pDS, pOS for the adjusting devices 4, 5. The setpoint pOS is the setpoint for the operator-side adjusting device 4, and the setpoint pOS is the setpoint for the drive-side adjusting device 5. The control device 9 determines the setpoints pDS, pOS taking into account the setpoint roll gap s*, the setpoint roll gap wedge k*, the symmetrical compensation value δs, and the asymmetrical compensation value δk. The setpoints pDS, pOS are generally position setpoints.

[0055] When determining the setpoints pDS, pOS, the control device 9 takes into account FIG 6 the target roll gap s* and the symmetrical compensation value δs with the same sign and the target roll gap wedge k* and the asymmetrical compensation value δk with the opposite sign. Specifically, the control device 9 adds the symmetrical target roll gap s*, the symmetrical compensation value δs, half of the target roll gap wedge k* and half of the asymmetrical compensation value δk and thus determines the target value pOS for the operator-side adjustment device 4. In a fundamentally analogous manner, the control device 9 adds the symmetrical target roll gap s* and the symmetrical compensation value δs and subtracts half of the target roll gap wedge k* and half of the asymmetrical compensation value δk and thus determines the target value pOS for the drive-side adjustment device 5. The determination is therefore carried out according to the relationships pDS = ƒ s ∗ + δ + k ∗ / 2 + δk / 2 and pOS = ƒ s ∗ + δ − k ∗ / 2 − δk / 2 .

[0056] In a step S7, the control device 9 controls the adjusting devices 4, 5 according to the determined target values ​​pDS, pOS. The control device 9 then returns to step S3 or (if a new mean target roll gap s* or a new target roll gap wedge k* is to be specified) to one of the steps S1 and S2.

[0057] The control device 9 executes (at least) steps S3 to S7 iteratively again and again. The execution takes place with a cycle time in the range of a few milliseconds, for example, between 1 ms and 20 ms. Often, the cycle time (in milliseconds) is a power of 2, i.e., 2 ms, 4 ms, 8 ms, or 16 ms. The cycle time also determines the timing of the following in connection with the FIG 7 bis 10 explained procedures.

[0058] To determine the symmetrical compensation value δs, the control device 9 implements according to FIG 5 an observer 12, hereinafter referred to as the first observer. According to FIG 5 The first observer 12 comprises a system model 13 of the rolling stand 1, a number of periodic disturbance models 14, and a state feedback 15. The control device 9 supplies the first observer 12 with a speed variable v' characteristic of the rolling speed v, the symmetrical target roll gap s*, and the symmetrical measured variable MS. The speed variable v' can, for example, be the rolling speed v itself. Using the first observer 12, the control device 9 determines the symmetrical compensation value δs.

[0059] According to FIG 5 only a single disturbance model 14 is present. Accordingly, the state feedback 15 also has only a single feedback block 16. According to FIG 8 However, several disturbance models 14 may also be present. In this case, the state feedback 15 has a separate feedback block 16 for each disturbance model 14. The FIG 8 The number of four disturbance models 14 shown is purely exemplary. More or fewer disturbance models 14 may be present. The disturbance models 14 can be assigned, as required, to specific rolls 3 or groups of rolls 3 of the rolling stand 1 and to specific fundamental vibrations or harmonics of the fundamental vibrations of the rolls in question.

[0060] According to FIG 8 The system model 13 comprises—regardless of the number of disturbance models 14—three elements 17, 18, and 19 connected in series. The front element 17 takes into account a reaction time TPC of the control devices 4, 5. The front element 17 can be designed, for example, as a PT1 element (generally: as a PTn element). The rear element 19 takes into account a reaction time TM of the measuring devices 6, 7, or 8. The rear element 19 can also be designed, for example, as a PT1 element (generally: as a PTn element).

[0061] The middle element 18 is designed as a multiplier. By means of the middle element 18, a sensitivity V of the symmetrical measured variable MS to the occurring eccentricities is taken into account. The sensitivity V can, if the thicknesses of the rolling stock 2 are measured as measured variables MOS, MDS, the value V = 1 1 + cm / cg where cm and cg are the spring constants of the rolling stock 2 and the rolling stand 1. If MOS, MDS forces are measured as measured variables, the sensitivity V can be set to the value V = cm ⋅ cg cm + cg If MOS and MDS trains are measured, the sensitivity V can be set to a value determined during testing.

[0062] The route model 13 of FIG 8 is designed as a linear system model. This design is preferred, but not mandatory. A non-linear system model can also be used. Furthermore, FIG 8 An integrator is shown within the system model 13. The integrator is used to adjust the operating point of the system model 13. Alternatively, the integrator could be omitted and the DC component of the symmetrical measured variable MS could be filtered out instead. In this case, however, the filter characteristics must be taken into account in the state feedback 15. Finally, the system model 13 can be expanded with an additional high-pass filter (DT1 element). In this case, the high-pass filter is arranged downstream of element 19.

[0063] FIG 9 shows the preferred structure of a single disturbance model 14. Such disturbance models 14 are known as such and are explained, for example, in EP 0 170 016 B1.

[0064] According to FIG 9 the disturbance model 14 has a front multiplier 20, a front integrator 21, a rear multiplier 22 and a rear integrator 23.

[0065] The signal flow is as in FIG 9 The control device 9 feeds the output signal z2 of the rear integrator 23 and an angular frequency ω to the front multiplier 20. The angular frequency ω is specified specifically for the respective disturbance model 14. It is given by ω = 2 ⋅ π ⋅ ƒ , where f is an integer multiple of the instantaneous speed of a considered roll 3 or (with the same diameters) of a considered group of rolls 3 of the rolling stand 1. The instantaneous speed of the considered roll 3 or the considered group of rolls 3 is determined by the speed variable v' in conjunction with the diameter of the considered roll 3 or the considered group of rolls 3 of the rolling stand 1. If the rolling speed v (and thus also the speed variable v') changes, the angular frequency ω is also adjusted and tracked accordingly.

[0066] The front multiplier 20 multiplies the signals supplied to it, thus forming the product of the output signal z2 of the rear integrator 23 and the angular frequency ω.

[0067] Furthermore, the control device 9 feeds the output signal of the front multiplier 20 to the front integrator 21. The front integrator 21 forms the integral of the input signal fed to it and thus determines its output signal z1.

[0068] Likewise, control device 9 feeds the output signal z1 of the front integrator 21 and the angular frequency ω to the rear multiplier 22. The rear multiplier 22 multiplies the signals fed to it, thus forming the product of the output signal z1 of the front integrator 21 and the angular frequency ω. Furthermore, control device 9 feeds the output signal of the rear multiplier 22 to the rear integrator 23. The rear integrator 23 forms the integral of the input signal fed to it and thus determines its output signal z2.

[0069] The output signal z1 of the front integrator 21 is fed by the control device 9 to the system model 13. There, it is - see FIG 8 - added by the control device 9 to the output signal of the first element 17 of the system model 13. If, as shown in FIG 8 several disturbance models 14 are present, the output signals z1 of the front integrators 21, as in FIG 8 indicated by a summation sign, are added together.

[0070] According to FIG 10 The control device 9 further feeds the output signals z1, z2 of both integrators 21, 13 and the angular frequency ω of the disturbance model 14 to the feedback block 16 of the state feedback 15. As already mentioned, the respective feedback block 16 is available individually for the respective disturbance model 14. The respective feedback block 16 compensates for the dynamic behavior of the adjusting devices 4, 5 and the other dead times and delay times of the rolling arrangement.

[0071] The feedback block 16 determines, based on the associated disturbance model 14, the component z for the compensation value δs. The feedback block 16 performs this determination using the angular frequency ω of the disturbance model 14, the output signals z1, z2 of the integrators 21, 23, the response time TPC of the adjustment devices 4, 5, and a resulting delay time TG. The resulting delay time TG can, for example, take into account delays caused by the signal communication from the measuring devices 6, 7, or 8 to the control device 9 or from the control device 9 to the adjustment devices 4, 5, and a cycle time of the control device 9.If thicknesses of the rolling stock 2 are used as measured variables MDS, MOS, the transport time required to transport a specific section of the rolling stock 2 from the roll gap of the rolling stand 1 to the measuring devices 6 can also be taken into account within the resulting delay time TG.

[0072] For example, the respective feedback block 16 can be configured as shown in FIG 10 first based on the relationships z1 ′ = z1 + ω ⋅ z 2 ⋅ TPC und z2 ′ = z2 − ω ⋅ z 1 ⋅ TPC determine a first modified output signal z1' and a second modified output signal z2' and then use the relationship z = z1 ′ ⋅ cos ω ⋅ TG − z 2 ′ ⋅ sin ω ⋅ TG determine the proportion z.

[0073] If only a single disturbance model 14 is present, the symmetric compensation value δs corresponds to the component z. If multiple disturbance models 14 are present, the symmetric compensation value δs corresponds to the sum of the components z of the disturbance models 14.

[0074] The procedure for determining and evaluating the symmetrical compensation value δs has been explained in detail above. To determine the asymmetrical compensation value δk, the control device 9 implements FIG 5a further observer 24, hereinafter referred to as the second observer. The second observer 24 is structurally designed in the same way as the first observer 12. It also operates in the same way. The only difference is that the control device 9 feeds other variables to the second observer 24, namely the speed variable v', the desired roll gap wedge k*, and the asymmetrical measured variable MA, and that the control device 9 determines the asymmetrical compensation value δk using the second observer 24. Furthermore, the above statements regarding the first observer 12 and its components 13 to 23 also apply 1:1 to the second observer 24.

[0075] The present invention offers many advantages. In particular, it compensates not only for symmetrical roll eccentricities, but also for asymmetrical roll eccentricities. Furthermore, retrofitting or expanding an existing symmetrical compensation system with asymmetrical compensation is easily possible. Thicknesses, tensions, or forces can be used as measured variables MOS and MDS as needed. The same structure can be used for cold and hot rolling. Due to the use of observers 12, 24, the determination of the roll eccentricities remains active even during rolling.

[0076] Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. List of reference symbols

[0077] 1Roll stand 2Rolling stock 3Rolls 4, 5Adjustment devices 6 to 8Measuring devices 9Control device 10Control program 11Machine code 12, 24Observer 13System model 14Disturbance model 15State feedback 16Feedback block 17, 18, 19Elements 20, 22Multipliers 21, 23Integrators k*Target roll gap wedge MA, MSMeasurement variables MDS, MOSMeasurement variables pDS, pOSSet values ​​s*Mean target roll gap S1 to S7Steps TGResulting delay time TMReaction time of the measuring devices TPCReaction time of the adjusting device VSensitivity vRolling speed v'Speed ​​variable z1, z2Output signals z1', z2'modified output signals zProportion δcasymmetric compensation value δssymmetric compensation value ωangular frequency

Claims

1. Operating method for a control device (9) of a rolling stand (1), in which a flat rolled stock (2) made of metal is rolled at a rolling speed (v), - wherein the control device (9) of the rolling stand (1) receives a symmetrical desired roll gap (s*), - wherein the control device (9) receives measured variables (MOS, MDS) detected by means of measuring devices (6 to 8) and dependent on a symmetrical eccentricity occurring in the rolling stand (1) during rolling of the rolled stock (2) and an asymmetrical eccentricity occurring in the rolling stand (1) during rolling of the rolled stock (2), - wherein the control device (9) for an operator-side and a drive-side adjusting device (4, 5) of the rolling stand (1), by means of which the roll gap is set on the drive side and operator side of the rolling stand (1), taking into account the desired roll gap (s*), an implicitly or explicitly given Target roll gap wedge (k*),a symmetrical compensation value (δs) and an asymmetrical compensation value (δk) determines respective target values ​​(pOS, PDS) and controls the adjusting devices (4, 5) accordingly, - wherein the control device (9) determines the symmetrical compensation value (δs) using the symmetrical measured variable (MS) and the asymmetrical compensation value (δk) using the asymmetrical measured variable (MA), - wherein the control device (9) takes into account the target roll gap (s*) and the symmetrical compensation value (δs) with the same sign and the target roll gap wedge (k*) and the asymmetrical compensation value (δk) with opposite signs when determining the target values ​​(pOS, pDS) for the adjusting devices (4, 5).

2. Operating method according to claim 1, characterized by thatthe control device (9) uses the symmetrical measured variable (MS) but not the asymmetrical measured variable (MA) to determine the symmetrical compensation value (δs) and uses the asymmetrical measured variable (MA) but not the symmetrical measured variable (MS) to determine the asymmetrical compensation value (δk).

3. Operating method according to claim 1 or 2, characterized by that the control device (9) determines the setpoint value (pOS) for the operator-side adjustment device (4) by adding the symmetrical setpoint roll gap (s*), the symmetrical compensation value (δs), half of the setpoint roll gap wedge (k*) and half of the asymmetrical compensation value (δk) and determines the setpoint value (pDS) for the drive-side adjustment device (5) by adding the symmetrical setpoint roll gap (s*) and the symmetrical compensation value (δs) and subtracting half of the setpoint roll gap wedge (k*) and half of the asymmetrical compensation value (δk).

4. Operating method according to claim 1, 2 or 3, characterized by that the control device (9) for the drive side and the operating side of the rolling stand (1) each receives a drive-side or operating-side measured variable (MDS, MOS) and determines the symmetrical measured variable (MS) by summation or averaging and the asymmetrical measured variable (MA) by subtraction.

5. Operating method according to one of the above claims, characterized by - that the control device (9) implements a first and a second observer (12, 24), each comprising a line model (13) of the rolling stand (1), a number of periodic disturbance models (14) and a state feedback (15), - thatthe control device (9) supplies the first observer (12) with a speed variable (v') characteristic of the rolling speed (v), the symmetrical target roll gap (s*) and the symmetrical measured variable (MS) and supplies the second observer (24) with the speed variable (v'), the target roll gap wedge (k*) and the asymmetrical measured variable (MA) and - that the control device (9) determines the symmetrical compensation value (δs) by means of the first observer (12) and the asymmetrical compensation value (δk) by means of the second observer (24).

6. Operating method according to claim 5, characterized by - that the respective system model (13) comprises three elements (17 to 19) connected in series, - that by means of the foremost link (17) a reaction time (TPC) of the adjusting devices (4, 5) is taken into account, - thatby means of the middle element (18) a sensitivity (V) of the measured variable (MS, MA) supplied to the respective system model (13) to the occurring eccentricities is taken into account and - that by means of the rear member (19) a reaction time (TM) of the measuring devices (6 to 8) is taken into account.

7. Operating method according to claim 6, characterized by that the respective system model (13) additionally comprises a further element which is arranged downstream of the rear element (19) and is designed as a high-pass filter, in particular as a DT1 element.

8. Operating method according to claim 5, 6 or 7, characterized by - that the respective disturbance model (14) has a front multiplier (20), a front integrator (21), a rear multiplier (22) and a rear integrator (23), - thatthe control device (9) supplies the front multiplier (20) with the output signal (z2) of the rear integrator (23) and an angular frequency (ω) of the respective disturbance model (14), - that the control device (9) feeds the output signal of the front multiplier (20) to the front integrator (21), - that the control device (9) supplies the output signal (z1) of the front integrator (21) and the angular frequency (ω) of the respective disturbance model (14) to the rear multiplier (22), - that the control device (9) feeds the output signal of the rear multiplier (22) to the rear integrator (23), - that the control device (9) feeds the output signal of the front integrator (z1) to the respective system model (13) and - thatthe control device (9) feeds the output signals (z1, z2) of both integrators (21, 23) and the angular frequency (ω) of the respective disturbance model (14) to a feedback block (16) of the state feedback (15) assigned to the respective disturbance model (14).

9. Operating method according to claim 8, characterized by that the control device (9) adds the output signal (z1) of the front integrator (21) to the output signal of the first element (17) of the respective system model (13).

10. Operating method according to claim 8 or 9, characterized by thatthe feedback block (16) assigned to the respective disturbance model (14) determines a respective component (z) for the respective compensation value (δs, δk) by utilizing the angular frequency (ω) of the respective disturbance model (14), the output signal (z1) of the front integrator (21) of the respective disturbance model (14), the output signal (z2) of the rear integrator (23) of the respective disturbance model (14), the reaction time (TPC) of the adjusting devices (4, 5) and a resulting delay time (TG).

11. Operating method according to claim 10, characterized by - that the feedback block (16) assigned to the respective disturbance model (14) based on the relationships z1 ′ = z1 + ω ⋅ z 2 ⋅ TPC und z2 ′ = z2 − ω ⋅ z 1 ⋅ TPC a first and second modified output signal (z1', z2') is determined, where z1' is the first modified output signal, z1 is the output signal of the front integrator (21), ω is the respective angular frequency, z2 is the output signal of the rear integrator (23), TPC is the reaction time of the adjusting devices (4, 5) and z2' is the second modified output signal, and - that the feedback block (16) assigned to the respective disturbance model (14) based on the relationship z = z1 ′ ⋅ cos ω ⋅ TG − z 2 ′ ⋅ sin ω ⋅ TG the respective component (z) for the respective compensation value (δs, δk) is determined, where z is the respective component for the respective compensation value (δs, δk) and TG is the resulting delay time.

12. Control program for a software-programmable control device (9) for a rolling stand (1), wherein the control program comprises machine code (11) which can be directly processed by the control device (9), wherein the processing of the machine code (11) by the control device (9) causes the control device (9) to carry out an operating method according to one of the above claims.

13. Control device for a rolling stand (1) in which a flat rolled product (2) made of metal is rolled at a rolling speed (v), wherein the control device is programmed with a control program (10) according to claim 12, so that the control device carries out an operating method according to one of claims 1 to 11.

14. Roll stand in which a flat metal rolling stock (2) is rolled at a rolling speed (v), - wherein the roll stand has an operator-side and a drive-side adjustment device (4, 5), by means of which the roll gap in which the rolling stock (2) is rolled can be adjusted on the drive side and operator side of the roll stand, - wherein the roll stand has measuring devices (6 to 8) by means of which measured variables (MOS, MDS) are recorded which are dependent on a symmetrical eccentricity occurring in the roll stand during rolling of the rolling stock (2) and an asymmetrical eccentricity occurring in the roll stand during rolling of the rolling stock (2), - wherein the measuring devices (6 to 8) are connected to a control device (9) of the roll stand for supplying the measured variables (MOS, MDS), and the control device (9) is connected to the adjustment devices (4, 5) for controlling the adjustment devices (4, 5). is,- wherein the control device (9) is designed as a control device according to claim 13, which controls the rolling stand according to an operating method according to one of claims 1 to 11.,

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