Method for operating a rolling stand, control system for a rolling stand and rolling unit

Abstract

Flat workpieces made of metal are rolled in a rolling stand. A position regulator for adjusting the positioning of an actuating element acquires an adjustment variable for the actuating element and accordingly actuates the actuating element depending on a synthesized position target value and a position actual value of the actuating element, by means of which the roll gap of the rolling stand is set. The synthesized position target value is acquired with a synthesized basic target value. The synthesized basic target value is acquired as the sum of a starting basic target value and an additional target value. The additional target value is acquired by an acquisition element with the actual tension on the feed side and the reference tension on the feed side and / or with the actual tension on the discharge side and the reference tension on the discharge side. Instead of the actual tension, a corresponding target tension of the respective tension regulation can also be used. In both cases, however, the reference tension is a different variable than the target tension.

Description

Technical Field

[0001] This invention relates to a method for operating a rolling mill stand for rolling flat workpieces made of metal.

[0002] Furthermore, the present invention relates to a control system for a rolling mill stand for rolling flat workpieces made of metal, wherein the control system is configured by means of hardware blocks and / or software programming such that it implements such an operating method during operation.

[0003] Furthermore, the present invention relates to a rolling unit for rolling a flat workpiece made of metal, wherein the rolling unit has a rolling stand for rolling the flat workpiece and a control system thereof. Background Technology

[0004] When rolling flat workpieces made of metal, one of the fundamental requirements of the rolling process is to produce flat workpieces whose thickness corresponds as closely as possible to a predetermined target thickness. The thickness of the workpiece exiting the rolling mill is specifically determined by the roll gap. The size of the roll gap is determined by setting the actuator accordingly to a specific position.

[0005] However, the size of the roll gap and the resulting thickness of the rolled piece are not determined solely by the position of the actuator. More precisely, in addition to wear, thermal crown, roll movement, and possibly other factors, the bounce of the rolling mill stand must also be taken into account. This bounce is generated by the rolling force and other forces acting on the rolling mill stand, such as bending forces.

[0006] In most cases, the rolling mill stands operate with adjustable roll gaps. In such cases, the thickness on the exit side is first determined in the pass configuration; the workpiece should be rolled to this thickness in the rolling mill stands. Furthermore, the anticipated rolling force is obtained, taking into account the characteristic parameters of the workpiece (such as its width, its feed side thickness, its temperature, and other parameters). If the spring modules of the rolling mill stands are utilized, the corresponding spring rate of the rolling mill stands is obtained. Then, taking into account the spring rate of the rolling mill stands and other parameters, such as crown caused by wear and / or temperature, a target position value for the actuator is obtained.

[0007] During the rolling process, the actual rolling force is obtained either directly by detection or based on the detected parameters. A calibration value is obtained using an AGC (automatic gauge control). This calibration value is acquired internally within the AGC via a spring module in the rolling mill stand.

[0008] The rolling of flat workpieces made of metal is often carried out such that the workpiece is clamped in a front device before the rolling stand and / or in a rear device after the rolling stand as it is rolled in the rolling mill. This allows for the application of a feed-side tension to the workpiece before the rolling stand or an output-side tension to the workpiece after the rolling stand. To better maintain a constant feed-side or output-side tension, corresponding loopers can be arranged before and / or after the rolling stand. Furthermore, the front device can be another rolling stand in the multi-stand rolling mill, provided that the rolling stand is part of a multi-stand rolling mill train but not the foremost rolling stand. Similarly, the rear device can be another rolling stand in the multi-stand rolling mill train, provided that the rolling stand is part of a multi-stand rolling mill train but not the last rolling stand. In other design options, the front-mounted device and / or the rear-mounted device could also be, for example, the coiler in a Steckel reversible hot roll mill. Other design options are also possible.

[0009] The tension on the discharge side, and even more so on the feed side, affects the rolling force. Specifically, the greater the tension, the lower the required rolling force. With lower rolling forces, the rolling mill stands bounce less. Unless this reduced bounce is taken into account, the tension thus affects the thickness to which the workpiece is rolled in the rolling mill stands.

[0010] From a solution perspective, this is not a problem, because the change in rolling force needs to be detected and the bounce caused by the change in rolling force can be corrected by the already mentioned AGC. However, the AGC requires a noteworthy time period to correct the bounce of the rolling mill stand. The input of the correction value is therefore only delayed. Furthermore, compensation via the AGC is often considered with restraint, because otherwise there is a risk that simultaneous correction of positioning via the AGC and tracking of tension via tension adjustment will lead to oscillations and instability. Finally, the correction value obtained by the AGC often contains errors, for example, due to frictional effects in the rolling mill stand or due to ineffective strip.

[0011] Furthermore, common practice is to activate the AGC only after the first rolling pass, i.e., with a delay. During the first rolling pass, the tension on the discharge side is zero because the head of the workpiece has not yet reached the subsequent device, which, in conjunction with the rolling mill stand, applies the discharge-side tension to the workpiece. However, the tension on the feed side can have a value completely different from zero. If the tension on the feed side changes in such a case, it affects the rolling force and thus the bounce of the rolling mill stand. However, because the AGC is only activated after the first rolling pass, the changes in thickness caused by the bounce due to variations in the rolling mill stand are not corrected during the first rolling pass stage, when the workpiece is to be rolled to that thickness in the rolling mill stand.

[0012] Similarly, common practice is to freeze the AGC (Automatic Gauge Control) before tapping (i.e., stop tracking the correction value acquired at the time of freezing) or limit the time variation of the correction value. During tapping, the tension on the feed side is 0 because the workpiece foot has already emerged from a pre-installed device that may apply the feed-side tension to the workpiece in conjunction with the rolling mill stand. However, the tension on the discharge side can have a value completely different from 0. If the discharge-side tension changes in such a case, it affects the rolling force and thus the bounce of the rolling mill stand. However, because the AGC is frozen before tapping or the time variation of the correction value acquired by the AGC is limited, the change in thickness caused by the bounce due to variations in the rolling mill stand is not corrected or is only insufficiently corrected during the tapping stage, to which the workpiece is to be rolled in the rolling mill stand.

[0013] An operating method of the type mentioned at the beginning is known from EP 3 231 522 A1. In this operating method, a positioning additional target value is obtained by means of a tension adjuster that adjusts the actual tension on the inlet side to the target tension on the inlet side, and this positioning additional target value is to be connected to the actual positioning target value. The actual positioning target value is the roll gap target value.

[0014] A similar operating method of the type mentioned at the beginning is also known from JP 2003-164 906 A. In this operating method, an additional positioning target value is obtained by means of a tension adjuster that adjusts the actual tension on the exit side to the target tension on the exit side, and this additional positioning target value is then applied to the actual positioning target value. The actual positioning target value is the roll gap target value.

[0015] A method of operating a rolling mill stand is also known from EP 2 620 233 A1, the rolling mill stand being used to roll a flat workpiece made of metal. In this method of operation, mass flow rate regulation is implemented, which itself affects the positioning system of the rolling mill stand. This sets the thickness of the workpiece exiting the rolling mill stand. In this method of operation, a tension regulator that adjusts the actual tension at the inlet side to a target tension at the inlet side affects the positioning system of the rolling mill stand. Summary of the Invention

[0016] The objective of this invention is to provide a feasible solution by means of which better compliance with the thickness of the rolled piece on the discharge side of the rolling mill stand can be guaranteed.

[0017] This task is solved by a method of operating a rolling mill stand for rolling flat workpieces made of metal. The invention also relates to other advantageous designs of said operating method.

[0018] In this running method,

[0019] A position adjuster for adjusting the positioning of the actuator obtains adjustment parameters for the actuator based on a synthesized target position value and an actual position value, and accordingly manipulates the actuator, wherein the roll gap of the rolling mill stand is set by means of the actuator.

[0020] - Obtain the synthesized location target value using the synthesized base target value.

[0021] -The base target value of the synthesis is obtained by summing the base target value and the additional target value as the starting point.

[0022] According to the present invention, the operation method of the above-mentioned type is designed in the following manner:

[0023] -The additional target value is obtained by the acquisition element in the case of the actual tension or corresponding target tension on the feed side adjusted by the tension on the feed side and the reference tension on the feed side, and / or the actual tension or corresponding target tension on the discharge side adjusted by the tension on the discharge side and the reference tension on the discharge side.

[0024] - wherein the reference tension on the feed side is a parameter different from the target tension on the feed side and / or the reference tension on the discharge side is a parameter different from the target tension on the discharge side.

[0025] In the simplest case, the synthesized target position value is the same as the synthesized base target value. The initial base target value typically does not depend on the tension on the feed side or the tension on the discharge side.

[0026] The actual tension on the feed side and / or the actual tension on the discharge side can be an actual value detected by measurement technology or a value obtained by means of a value detected by measurement technology. The use of either the actual value or the target value is possible because the tension adjustment typically has sufficient dynamics and quality, and therefore the actual value and the target value correspond within a sufficient range.

[0027] Typically, the rolling mill stands operate with adjustable roll gaps. Furthermore, the tension adjustment on the feed side typically affects the roll circumferential speed and / or the input speed, at which the flat workpiece is rolled in the rolling mill stands and exits from a device positioned preceding the rolling mill stands at the input speed. Similarly, the tension adjustment on the output side typically affects the roll circumferential speed and / or the output speed, at which the flat workpiece enters a device positioned following the rolling mill stands. Typically, the tension adjustment affects only one device at a time, i.e., either the preceding device or the rolling mill stands, or either the rolling mill stands or the following device.

[0028] If a correlation exists between the additional target value and the tension state (target or actual) on the feed side, the acquisition element preferably obtains the additional target value based on the product of the sensitivity of the feed side and the actual tension on the feed side, or the difference between the corresponding target tension and the reference tension on the feed side. Similarly, the acquisition element preferably obtains the additional target value based on the product of the sensitivity of the discharge side and the difference between the actual tension on the discharge side, or the difference between the corresponding target tension and the reference tension on the discharge side, if a correlation exists between the additional target value and the tension state on the discharge side. Therefore, obtaining the additional target value and the base target value synthesized therefrom becomes particularly simple.

[0029] Preferably, the additional target value is obtained by the acquiring element based on the product of the sensitivity of the feed side and the difference between the actual tension or the corresponding target tension of the feed side and the reference tension of the feed side, and / or based on the product of the sensitivity of the discharge side and the difference between the actual tension or the corresponding target tension of the discharge side and the reference tension of the discharge side. In this way and method, the additional target value can be obtained particularly easily and reliably.

[0030] Preferably, the sensitivity of the feed side and / or the sensitivity of the discharge side are pre-defined for the acquisition element by a higher-level control device.

[0031] For example, the corresponding sensitivities can be stored in the upper-level control device in the form of tables, etc. In these tables, the corresponding sensitivities can be stored based on the geometry and other characteristics of the rolled piece (such as its chemical composition and temperature). However, it is preferable that the feed-side sensitivities and / or discharge-side sensitivities are obtained by the upper-level control device within the range of the pass scheme calculation, based on an evaluation of the rolling model. The rolling model is based on mathematical and physical equations describing the rolling process in the rolling mill stand. Thus, “point-precise” acquisition of the feed-side sensitivities and / or discharge-side sensitivities is possible. The rolling model can always be refitted whenever needed.

[0032] The mathematical and physical equations of the rolling model are typically differential and / or algebraic equations. Such models are well known to those skilled in the art. Purely exemplary reference can be made to J.M. Alexander's paper "On the theorie of rolling," published in the Proceedings of the Royal Society London, 1972, edition 326, pp. 553-563.

[0033] Similarly, the upper-level control device can pre-determine the reference tension on the feed side and / or the reference tension on the discharge side for the acquisition element. The corresponding reference tension can be acquired or estimated by the upper-level control device within the range calculated for the pass sequence.

[0034] The preferred operating method is designed such that the higher-level control device, for example, is within the range of the track number scheme calculation.

[0035] - Obtain the initial basic target values ​​and the target tension on the feed side and / or the target tension on the discharge side based on the target thickness that the flat rolled piece should have when it exits the rolling mill stand, as well as the reference tension on the feed side and / or the reference tension on the discharge side.

[0036] -The initial target value is pre-given to the adjustment unit, which includes the position adjuster and the acquisition element, and

[0037] - A target tension is pre-set for the feed side of the preceding tension adjuster, which adjusts the actual tension on the feed side to the target tension on the feed side, and / or a target tension is pre-set for the discharge side of the subsequent tension adjuster, which adjusts the actual tension on the discharge side to the target tension on the discharge side.

[0038] Preferably, the synthesized position target value is obtained at least during the rolling of the middle section of the workpiece, using the correction value obtained with the actual rolling force. This achieves an AGC (Automatic Gain Control). Therefore, it is possible to combine the operating method according to the invention with the AGC.

[0039] Preferably, the synthesized base target value is considered in addition to the actual rolling force within the range of the obtained correction value. This improves the dynamics when obtaining the correction value.

[0040] Preferably, the synthesized position target value is obtained at least during rolling of the head and / or foot of the workpiece without utilizing the actual rolling force. In this case, the invention then compensates for tension variations and the resulting rolling force variations when the AGC is not in operation.

[0041] The last mentioned processing method can also be combined with the processing method where the AGC operates during the rolling of the intermediate section of the workpiece. In this case, the AGC can be optionally activated when switching from rolling the head of the workpiece to rolling the intermediate section. Similarly, the AGC can be deactivated (frozen or restricted in its operation) when switching from rolling the intermediate section to rolling the foot of the workpiece.

[0042] Preferably, the synthesized position target value is obtained by utilizing the deviation between the thickness of the rolled piece detected on the discharge side of the rolling mill stand and the target thickness. This allows for the correction of any remaining errors.

[0043] Furthermore, the task is accomplished by a control system for a rolling mill stand used to roll flat workpieces made of metal. According to the invention, the control system implements the operating method of the invention during operation via hardware blocks and / or software programming.

[0044] Furthermore, the task is accomplished by a rolling unit for rolling a flat workpiece made of metal. According to the invention, the control system in the rolling unit of the type mentioned at the beginning is configured as the control system according to the invention. Attached Figure Description

[0045] The features, characteristics, and advantages of the present invention described above, and how they can be achieved, will become clearer and more readily understood in conjunction with the following description of embodiments, which will be explained in detail with reference to the accompanying drawings. The drawings are illustrated schematically as follows:

[0046] Figure 1 The rolling mill stand and its control are shown;

[0047] Figure 2The rolling mill is shown in its first operating state.

[0048] Figure 3 It shows Figure 2 The rolling mill in its second operating state;

[0049] Figure 4 It shows Figure 2 The rolling mill in its third operating state;

[0050] Figure 5 The structure of the regulating unit is shown;

[0051] Figure 6 The acquisition element is shown;

[0052] Figure 7 It shows Figure 5 Supplement to the adjustment unit;

[0053] Figure 8 It shows Figure 7 Supplementary modifications;

[0054] Figure 9 A timeline chart is shown; and

[0055] Figure 10 It shows Figure 5 One design scheme for the adjustment unit. Detailed Implementation

[0056] according to Figure 1 The workpiece 2 should be rolled in rolling mill stand 1. In said rolling mill stand 1, in... Figure 1 The drawing (and if shown, in other figures) shows only the work rolls. However, the rolling mill stand 1 typically has at least support rolls in addition to the work rolls (four-roll stand), and if necessary, intermediate rolls arranged between the work rolls and support rolls (six-roll stand). The rolled piece 2 is made of metal, often steel, in some cases aluminum, and rarely other metals such as copper. Furthermore, the rolled piece 2 is a flat rolled piece, i.e., strip (usually) or plate (exceptions).

[0057] The rolling mill stand 1 typically operates with an adjustable roll gap. Furthermore, the rolling of the workpiece 2 in the rolling mill stand 1 is performed at a roll circumferential speed vU. The associated drive unit and its control are not shown.

[0058] According to Figure 2 and 3As illustrated in the diagram, the rolled piece 2 can be held in a device 3 arranged before the rolling mill 1 during its rolling in the rolling mill stand 1. In this case, the rolled piece 2 exits from the preceding device 3 at an input speed vZ. Furthermore, the rolled piece 2 is loaded on the feed side of the rolling mill stand 1 with the actual tension ZE on the feed side. A looper can be arranged between the preceding device 3 and the rolling mill stand 1. The looper is not shown together. The preceding device 3 is based on... Figure 2 and 3 The diagram in the image can be specifically configured as another rolling mill stand. However, it can also be configured differently, for example, as a coiler or as a drive roll assembly. The input speed vZ is... Figure 2 and 3 The speed is shown as the circumferential speed. If the preceding device 3 is a rolling mill stand, then the forward slip must be taken into account as well.

[0059] The actual tension ZE on the feed side is typically adjusted to the corresponding target tension ZE* by means of a corresponding tension adjustment. In this case, the actual tension ZE on the feed side and the target tension ZE* on the feed side are fed to the preceding tension adjuster 24. The preceding tension adjuster 24, using the actual tension ZE on the feed side and the target tension ZE* on the feed side, mostly uses the difference between the two mentioned tensions ZE and ZE* to obtain the preceding adjustment parameter δvE, and loads the adjustment parameter onto the actuator so that the actual tension ZE on the feed side is commensurate with or at least close to the target tension ZE* on the feed side. The preceding adjustment parameter δvE can in particular be a speed-added target value, which affects the roll circumferential speed vU or, in the opposite sign, the input speed vZ.

[0060] In a similar manner, the rolled piece 2 can be rolled in the rolling mill stand 1 according to the conditions at which it is rolled. Figure 3 and 4 The illustration is maintained in the device 4 arranged after the rolling mill stand 1. In this case, the rolled piece 2 enters the rear device 4 at an output speed vA. Furthermore, the rolled piece 2 is loaded on the discharge side of the rolling mill stand 1 with the actual tension ZA on the discharge side. A looper can also be arranged between the rolling mill stand 1 and the rear device 4. This looper is not shown together. The rear device 4 is based on... Figures 3 to 5 The diagram in the image can be specifically configured as another rolling mill stand. However, it can also be configured differently, for example, as a coiler or as a drive roll assembly. The output speed vA is... Figure 3 and 4 The speed is shown as the circumferential speed. If the rear-mounted device 4 is a rolling mill stand, then the backward slip must be taken into account as well.

[0061] The actual tension ZA on the discharge side is typically adjusted to a target tension ZA* using a corresponding tension adjustment. In this case, the actual tension ZA and the target tension ZA* on the discharge side are fed to the subsequent tension adjuster 25. The subsequent tension adjuster 25, using the difference between the actual tension ZA and the target tension ZA* on the discharge side, usually obtains the subsequent adjustment parameter δvA, and applies this adjustment parameter to the actuator so that the actual tension ZA on the discharge side is commensurate with or at least close to the target tension ZA* on the discharge side. The subsequent adjustment parameter δvA can in particular be a speed-added target value, which affects the circumferential speed vU of the roll shaft or, in the opposite sign, the output speed vA.

[0062] The rolling mill stand 1 typically has a number of actuators by means of which the rolling process is influenced. Examples of such actuators are bending systems (by means of which the bending of the rolls is set), sliding devices (by means of which the roll pairs can move axially in opposite directions), roll cooling devices, roll gap lubrication devices, and many other devices. Within the scope of the invention, actuator 5 (see [link to invention]) is of particular importance. Figure 5 The roller gap of the rolling mill stand 1 is set by means of this actuator. Therefore, only this actuator 5 and its operation will be discussed in detail below.

[0063] To adjust the positioning of the actuator 5, a synthesized target position value s* is pre-given to the position adjuster 6 of the adjustment unit 7. Furthermore, the actual value s of the actuator 5 is fed to the position adjuster 6. Based on these two parameters s* and s, the position adjuster 6 obtains the adjustment parameter q for the actuator 5 and controls the actuator 5 accordingly. The adjustment unit 7 is an important component of the control system according to the invention.

[0064] The actuator 5 is usually based on Figure 5 The diagram is constructed as a hydraulic cylinder unit. In this case, the adjustment parameter q affects the hydraulic system 8, which, as needed, applies a high working pressure pP (= pump pressure) or a low working pressure pT (= tank pressure) to the working chambers 9 and 10 of the hydraulic cylinder unit. In this case, the adjustment parameter q can be, for example, the hydraulic flow to be delivered. Especially in this design, the position adjuster 6 is based on... Figure 5The diagram can be configured as a proportional controller (P controller). In rare cases, as an alternative or supplementary solution, the roll gap can also be adjusted by means of an electric drive that affects the screw turning. In such cases, the position adjuster 6 is often configured as a proportional-integral (PI) controller.

[0065] The synthesized position target value s* is obtained using the synthesized base target value s1*. Following... Figure 5 In the design scheme, the synthesized target position value s* is the same as the synthesized base target value s1*. However, other parameters can also be incorporated into the synthesized target position value s*. This will become clear from the subsequent explanation. The synthesized base target value s1* is obtained by utilizing the actual tension ZE on the feed side and / or the actual tension ZA on the discharge side.

[0066] according to Figure 5 The diagram shows that the synthesized basic target value s1* is obtained by summing the basic target value s0* and the additional target value δs1* at node 11. The initial basic target value s0* is generally independent of the actual tension ZE on the feed side and the actual tension ZA on the discharge side. The additional target value δs1*, however, depends on the actual tension ZE on the feed side and the actual tension ZA on the discharge side. Specifically, the additional target value δs1* is obtained by the acquisition element 13 using the actual tension ZE on the feed side and the reference tension ZER on the feed side. Alternatively or supplementarily, the additional target value δs1* can be obtained by the acquisition element 13 using the actual tension ZA on the discharge side and the reference tension ZAR on the discharge side.

[0067] To obtain the additional target value δs1*, it is possible to... Figure 6 The illustration shows, for example, the actual tension ZE on the feed side being fed to the acquisition block 12 of the acquisition element 13. In this case, the feed side component δs1E* of the additional target value δs1* is acquired in the acquisition block 12 using the actual tension ZE on the feed side and the reference tension ZER on the feed side. For example, it is possible to... Figure 6 The diagrams in the diagrams are based on the relational formulas.

[0068] δs1E * =SE·(ZE-ZER) (1)

[0069] To obtain the feed-side component δs1E*. Here, SE is the feed-side sensitivity. The reference tension ZER on the inlet side can also have a value of 0 if necessary. In some cases, it can even change over time. Typically, it is also necessary in this case to change the initial base target value s0* within the corresponding range.

[0070] For example, according to Figure 1 The diagram shows that the upper-level control device 14 pre-determines the sensitivity SE on the feed side and the reference pull ZER on the inlet side for the acquisition element 13. The control device 14 (as long as it exists) is another important component of the control system.

[0071] In a similar manner, in order to obtain the additional target value δs1*, it is possible to... Figure 6 The illustration shows, for example, the actual tension ZA on the discharge side being fed to the acquisition block 15 of the acquisition element 13. In this case, the discharge side component δs1A* of the additional target value δs1* is acquired in the acquisition block 15 using the actual tension ZA on the discharge side and the reference tension ZAR on the discharge side. For example, the discharge side component δs1A* can be determined based on... Figure 6 The diagrams in the diagrams are based on the relational formulas.

[0072] δs1A * =SA·(ZA-ZAR) (2)

[0073] To obtain. Here, SA refers to the sensitivity on the discharge side. It can be obtained based on... Figure 1 The diagram also shows that the upper-level control device 14 pre-sets the sensitivity SA and reference tension ZAR on the discharge side for the acquisition element 13. The reference tension ZAR on the inlet side can also have a value of 0 if necessary. In some cases, it can even change over time. Similar to the change in the reference tension ZER on the feed side, it may be necessary to change the initial base target value s0* within the corresponding range when the reference tension ZAR on the discharge side ends.

[0074] It is possible to use only one of the two tensions ZE and ZA. In this case, the additional target value δs1* is the same as the corresponding components δs1E* and δs1A*. However, it is generally necessary to use both tensions ZE and ZA. For the acquisition of linearization, the acquisition element 13 has a node 16 in which the additional target value δs1* is acquired as the sum of the two components δs1E* and δs1A*. Alternatively, it is possible to use the corresponding target values ​​ZE* and ZA* instead of the actual tensions ZE and ZA.

[0075] The target tensions ZE* and ZA*, that is, the target values ​​ZE* and ZA* that are supplied to the respective tension adjusters 24 and 25 and are thus effective for the tension adjustment, are parameters different from the reference tensions ZER and ZAR. Although it is possible, in practice, to derive the target tensions ZE* and ZA* from the reference tensions ZER and ZAR, there is no identical consistency. Although the specific values ​​may be temporarily the same, this is not systematic and is not always the case.

[0076] Therefore, for example, it is possible that the target tension ZE*, ZA* can be predetermined by an operator (not shown) or changed by an operator during the rolling of the flat workpiece 2. The reference tensions ZER, ZAR, however, cannot be changed by the operator. Furthermore, it is possible that the target tensions ZE*, ZA* can be changed over time by the superior control device 14 for process reasons, while the reference tensions ZER, ZAR are maintained. This will be explained in detail below with the aid of an example. Within the scope of this example, it is assumed that the preceding device 3 and the following device 4 are rolling mill stands, and that a rolling mill stand is also arranged before the preceding device 3 and after the following device 4.

[0077] The head 20 of the rolled piece 2 (see...) Figure 2 For example, it reaches the rolling mill stand 1 at time t1, the subsequent device 4 at time t2, and the rolling mill stand located after the subsequent device 4 at time t3. Similarly, for example, the rolling foot 21 of the rolled piece 2 (see...) Figure 4 It reaches the rolling mill stand arranged before the preceding device 3 at time t4, the preceding device 3 at time t5, and the rolling mill stand 1 at time t6. The time t4 is usually after time t3.

[0078] Figure 2 The rolling process at time t1 is shown when the workpiece 2 is being rolled. From time t1 onwards, the actual tension ZE on the feed side can be applied. This was not possible before time t1. Before time t1, the actual tension ZE on the feed side was thus forced to be 0. The actual tension ZA on the discharge side is also 0 because the workpiece 2 is not yet present on the discharge side of the rolling mill stand 1, and the workpiece 2 has not yet reached the downstream device 4.

[0079] In a similar way, Figure 4The rolling process at time t6 is shown during the rolling of workpiece 2. Until time t6, the actual tension ZA on the discharge side can still be applied. After time t6, this is no longer possible. After time t6, the actual tension ZA on the discharge side is thus forcibly 0. The actual tension ZE on the feed side is also 0 because workpiece 2 is no longer present on the feed side of the rolling mill stand 1, and workpiece 2 has, in particular, been out of the preceding device 3 for a considerable period of time.

[0080] Figure 3 The diagram illustrates the rolling process of the workpiece 2 between times t1 and t6, more precisely between times t2 and t5. During this time period, corresponding actual tensile forces ZE and ZA are applied to the workpiece 2 at least on one side (i.e., on the feed side or the discharge side), for a portion of this time period, or even on both sides (i.e., on both the feed side and the discharge side).

[0081] In a static state, when the workpiece 2 is rolled in all the rolling stands of the example just explained, the target tensions ZE* and ZA* correspond to the reference tensions ZER and ZAR, that is, have the same value. This static state, in terms of the predefined target values ​​ZE* and ZA* for the tension adjusters 24 and 25, is between time t3 and t4.

[0082] For example, during the time interval between time t1 and time t2, the subsequent tension regulator 25 may be inactive due to its principle. This is because it is impossible to apply the actual tension ZA on the discharge side of the rolling mill stand 1 to the rolled piece 2. However, obtaining the discharge side component δs1A* of the additional target value δs1* is entirely possible during this time interval. Furthermore, during this time interval, although the preceding tension regulator 24 may be active, it is also possible that at time t1 (or shortly thereafter), the corresponding target value ZE* = ZER is not immediately supplied to the preceding tension regulator 24, but rather the target value ZE* is increased from 0 to the value of the corresponding reference tension ZER by means of a ramp.

[0083] In a similar manner, it is possible that during the time interval between time t2 and time t3, although the subsequent tension regulator 24 is active, it does not immediately supply the corresponding target value ZA* = ZAR to the subsequent tension regulator 25 at time t2 (or shortly thereafter), but instead raises the target value ZA* from 0 to the value of the corresponding reference tension ZAR by means of a ramp.

[0084] In a similar manner, it is possible that during the time period between time t4 and time t5, although the preceding tension regulator 24 is active, the target value ZE* delivered to the preceding tension regulator 24 will be reduced from the value ZE* = ZER that existed at the beginning of the mentioned time period to the value 0 by means of a ramp.

[0085] Furthermore, during the time period between time t5 and time t6, the preceding tension regulator 24 may not function due to its inherent principle. This is because the actual tension ZE on the feed side cannot be applied to the workpiece 2 from the feed side of the rolling mill stand 1. However, obtaining the feed side component δs1E* of the additional target value δs1* is entirely possible during this time period. Additionally, during this time period, the subsequent tension regulator 25 may function. However, it is possible that during the aforementioned time period, the target value ZA* delivered to the subsequent tension regulator 25 may be reduced from the initial value ZA* = ZAR to a value of 0 by means of a ramp.

[0086] The sensitivity SE on the feed side and / or the sensitivity SA on the discharge side, as well as other possible values ​​such as the reference tensile force ZER and / or ZAR and / or the initial base target value s0*, can be provided by the upper-level control device 14.

[0087] The regulator performs real-time adjustments during the rolling process of the workpiece. The entire regulator system is commonly referred to in the industry as an L1 system. The higher-level control device 14 therefore functions as a unit, which is commonly referred to in the industry as an L2 system. The higher-level control device 14... Figure 1 The illustrations include, in particular, a rolling model 17, in which the rolling process in the rolling mill stand 1 is modeled. The rolling model 17 is based on mathematical-physical equations describing the rolling process. The higher-level control device 14, using the rolling model 17, acquires the aforementioned parameters SE and / or SA and / or ZER and / or ZAR and / or s0*, and, if necessary, additional parameters.

[0088] For example, the upper-level control device 14 performs a pass scheme calculation before rolling the workpiece 2 in the rolling mill stand 1. In this pass scheme calculation, the upper-level control device acquires the aforementioned parameters and, if necessary, other values. The upper-level control device 14 provides the acquired values ​​to the lower-level regulator (e.g., the position regulator 6 of the adjustment unit 7). Specifically, the upper-level control device 14, within the range of the pass scheme calculation, calculates based on the target thickness d* (see...). Figure 1The initial target value s0* is obtained by using the reference tension ZER on the feed side and / or the reference tension ZAR on the discharge side, along with the target tension ZE* on the feed side and / or the target tension ZA* on the discharge side. Alternatively, the target thickness d* can be pre-given to the upper-level control device 14 or obtained independently by the upper-level control device 14. The reference tensions ZER and ZAR are typically estimated by the upper-level control device 14. Starting from these values ​​d*, ZER, and ZAR, the upper-level control device 14 obtains the necessary rolling force and the necessary positioning (Anstellung). The necessary rolling force corresponds to the reference rolling force FR, and the necessary positioning corresponds to the initial target value s0*. The upper-level control device 14 pre-given the initial target value s0* to the adjustment unit 7. Similarly, the upper-level control device 14 pre-sets the target tension ZE* on the feed side for the front tension regulator 24 and pre-sets the target tension ZA* on the discharge side for the rear tension regulator 25.

[0089] The upper-level control device 14 can acquire the feed-side sensitivity SE, for example, by acquiring the effect of changes in the feed-side tension ZE on the actual rolling force F for the desired operating point of the rolling mill stand 1, and further, the effect of changes in the rolling force F on the auffing of the rolling mill stand 1. The product of the two aforementioned effects produces the feed-side sensitivity SE. Similarly, the upper-level control device 14 can acquire the discharge-side sensitivity SA, by acquiring the effect of changes in the discharge-side tension ZA on the rolling force F for the desired operating point of the rolling mill stand 1, and further, the effect of changes in the rolling force F on the auffing of the rolling mill stand 1. The product of the two aforementioned effects produces the discharge-side sensitivity SA. In a completely equivalent manner, it is also possible to pre-define the acquisition element 13 with basic parameters for the sensitivities SE and SA, namely, the effect of the change in tension ZE on the feed side on the actual rolling force F, the effect of the change in tension ZA on the discharge side on the rolling force F, and the effect of the change in rolling force F on the bounce of the rolling mill stand 1. In this case, the acquisition element 13 can acquire the sensitivities SE and SA themselves. Furthermore, in this case, the acquisition element 13 can also acquire, in particular, the expected change in rolling force δF corresponding to the change in tension ZE and ZA.

[0090] Typically, the synthesized target value s* is not the same as the synthesized base target value s1*, but is obtained using additional correction parameters.

[0091] Therefore, according to Figure 7The illustration in the diagram might, for example, involve obtaining the synthesized position target value s* using the correction value δs2* obtained when using the rolling force F. For instance, the synthesized position target value s* can be obtained in node 18 as the sum of the synthesized base target value s1* and the correction value δs2*. In this case, the correction value δs2* is obtained in acquisition block 19 using the actual rolling force F. Acquisition block 19 thus implements AGC, in which additional bounce of the rolling mill stand 1 is compensated (at least to a large extent). The additional bounce of the rolling mill stand 1 is caused by the deviation between the actual rolling force F and the reference rolling force FR. For good order, it should be noted that in Figure 7 Only the additional components of the adjustment unit 7 are shown. For the basic design of the adjustment unit 7, all other components should be considered. Figure 5 and 6 .

[0092] In the simplest case, the actual rolling force F and the reference rolling force FR are simply fed to the acquisition block 19 as input parameters. Figure 1 The diagram shows that the upper-level control device 14 provides a reference rolling force FR to the acquisition block 19. However, in many cases, in addition to the actual rolling force F, the acquisition block 19 is also supplied with values ​​that correspond to the synthesized position target value s*, in addition to the correction value δs2* acquired by the acquisition block 19. For example, a synthesized base target value s1* can be supplied to the acquisition block 19. In this case, the acquisition block 19 also takes into account the synthesized base target value s1* within the range of the acquired correction value δs2*. Furthermore, in this case, the acquisition element 13 acquires the expected change δF of the reference rolling force FR in addition to the target value δs1*. The expected change δF of the reference rolling force FR is taken into account by the acquisition block 19 when acquiring the correction value δs2*. Additionally, the actual position value s can also be supplied to the acquisition block 19 when necessary.

[0093] It is possible that during the rolling of the workpiece 2, a combination is always performed in the rolling mill stand 1. Figure 7 The processing method explained is as follows: The correction value δs2* is acquired and applied in the rolling mill without depending on which section of the workpiece 2 is being rolled. However, in many cases, the correction value δs2* is acquired or switched to active only during rolling of the middle section of the workpiece 2. During rolling of the head 20 and / or foot 21 of the workpiece, the composite position target value s* is often acquired without utilizing the actual rolling force F. This will be discussed in conjunction with... Figure 8and 9 In additional reference Figures 2 to 4 Please explain in detail in the following circumstances.

[0094] Figure 8 by Figure 7 The adjustment unit 7 is the starting point. Figure 8 In this process, an activation signal A and a reset signal R can be transmitted to the acquisition block 19. According to... Figure 9 The activation signal A has a value of 0 or 1. A value of 1 for the activation signal A causes the acquisition block 19 to be activated. In this case, the acquisition block 19 acquires the corresponding valid correction value δs2* using the rolling force F. As a result, the synthesized position target value s* is acquired using the rolling force F. A value of 0 for the activation signal A causes the acquisition block 19 to be deactivated. In this case, the acquisition block 19 outputs the last acquired correction value δs2*, but no longer tracks the correction value δs2*. As a result, the synthesized position target value s* is acquired without using the rolling force F. The reset signal R is only sent to the acquisition block 19 when the workpiece is not being rolled in the rolling mill stand 1. The result of sending the reset signal R is that the last acquired correction value δs2* is reset to 0.

[0095] The activation signal A varies as a function of time t. Until time t1, the activation signal A has a value of 0. Thereafter, the activation signal A typically rises abruptly to a value of 1. At time t6, the activation signal A typically drops abruptly back to a value of 0. (Following the...) Figure 9 At time t7, which is after time t6, the reset signal R is given in advance (for a short time).

[0096] Figure 10 It shows Figure 5 Another design scheme for the adjustment unit 7. However, Figure 10 The design scheme can also be based on... Figure 7 and 8 The design scheme of the adjustment unit 7. According to... Figure 10 The thickness d of the rolled piece 2, i.e., its actual value, is detected on the discharge side of the rolling mill stand 1 using a corresponding measuring device 22. In the acquisition block 23, the thickness d is compared with the target thickness d*. Based on the deviation between the thickness d of the rolled piece 2 and the target thickness d*, a correction parameter δs3* is acquired in the acquisition block 23. The correction parameter δs3* is then sent to node 18. Thus, the synthesized position target value s* is also acquired using the correction parameter δs3*. This processing method allows compensation for all remaining types of errors.

[0097] This invention has many advantages. If and only as long as the AGC is active, i.e., especially when rolling the intermediate section of the roll 2, the AGC and the thickness adjustment, possibly based on the measurement of thickness d, no longer need to compensate for errors in the positioning of the rolling mill stand 1 caused entirely by changes in the rolling force F, because partial compensation has already been achieved through the acquisition of the combined position target value s*, which depends on the tension, i.e., through correction based on the tension ZE and ZA. If and only as long as the AGC is inactive, i.e., especially during the initial rolling pass and during the tapping stage, the thickness error, which would otherwise be impossible to correct, can be at least partially corrected through the acquisition of the combined position target value s*, which depends on the tension. As a result, the initial and / or final sections of the roll 2 (whose thickness d deviates from the target thickness d* by a margin greater than the permissible tolerance) can be significantly shortened, often by about half. Furthermore, there is an incentive to improve the structure of the looper adjustment immediately following the initial rolling pass.

[0098] Although the invention has been illustrated and described in detail with reference to preferred embodiments, the invention is not limited to the disclosed examples and other variations can be derived by those skilled in the art without departing from the scope of protection of the invention.

[0099] List of reference numerals in the attached diagram:

[0100] 1 Rolling mill stand

[0101] 2 Rolled parts

[0102] 3, 4. Front / rear devices

[0103] 5. Implementing agencies

[0104] 6 Position Adjuster

[0105] 7 Adjustment Unit

[0106] 8. Hydraulic System

[0107] Studios 9 and 10

[0108] Nodes 11, 16, and 18

[0109] Get blocks 12, 15, 19, 23

[0110] 13 Obtaining Components

[0111] 14 Control device

[0112] 17 Rolling Mold

[0113] 20 Rolled part head

[0114] 21. Rolled part foot

[0115] 22 Measuring device

[0116] 24, 25 Tension Adjusters

[0117] A Activation Signal

[0118] d, d* Thickness (actual and target)

[0119] F Actual rolling force

[0120] FR Reference Rolling Force

[0121] pP, pT working pressure

[0122] q Adjustment parameter

[0123] R Reset Signal

[0124] actual value of position s

[0125] s* Target position value for synthesis

[0126] s0*, s1* Basic target values

[0127] t time

[0128] Time intervals from t1 to t7

[0129] vA, vU, vZ speed

[0130] ZA, ZE, ZA*, ZE* Tension (Actual and Target)

[0131] ZAR, ZER reference tensile strength

[0132] δs1* Additional target value

[0133] δs1A* and δs1E* components

[0134] δs2* correction value

[0135] δs3* Correction parameter

[0136] δvA, δvE adjustment parameters

Claims

1. A method for operating a rolling mill stand (1) for rolling a flat workpiece (2) made of metal. -The position adjuster (6) used to adjust the positioning of the actuator (5) obtains the adjustment parameter (q) for the actuator (5) based on the synthesized target position value (s*) and actual position value (s) of the actuator (5) and controls the actuator (5) accordingly, wherein the roll gap of the rolling mill stand (1) is set by means of the actuator (5). -The synthesized position target value (s*) is obtained by using the synthesized basic target value (s1*). -The base target value (s1*) of the synthesis is obtained by summing the base target value (s0*) and the additional target value (δs1*). -The additional target value (δs1*) is obtained by the acquisition element (13) in the case of the actual tension (ZE) or the corresponding target tension (ZE*) of the feed side adjusted by the tension of the feed side and the reference tension (ZER) of the feed side and / or in the case of the actual tension (ZA) or the corresponding target tension (ZA*) of the discharge side adjusted by the tension of the discharge side and the reference tension (ZAR) of the discharge side. -The reference tension (ZER) on the feed side is a parameter different from the target tension (ZE*) on the feed side and / or the reference tension (ZAR) on the discharge side is a parameter different from the target tension (ZA*) on the discharge side.

2. The operating method according to claim 1, Its features are, The rolling mill stand (1) operates with the roll gap adjusted.

3. The operating method according to claim 1 or 2, Its features are, The tension adjustment on the feed side affects the roll circumferential speed (vU) and / or input speed (vZ), wherein the flat workpiece (2) is rolled in the rolling mill (1) at the roll circumferential speed, and the flat workpiece (2) exits from the device (3) which is in front of the rolling mill (1) at the input speed, and / or the tension adjustment on the discharge side affects the roll circumferential speed (vU) and / or output speed (vA), wherein the flat workpiece (2) enters the device (4) which is in rear of the rolling mill (1) at the output speed.

4. The operating method according to claim 1 or 2, Its features are, The additional target value (δs1*) is obtained by the acquisition element (13) based on the product of the sensitivity (SE) of the feed side and the difference between the actual tension (ZE) or the corresponding target tension (ZE*) of the feed side and the reference tension (ZER) of the feed side, and / or based on the product of the sensitivity (SA) of the discharge side and the difference between the actual tension (ZA) or the corresponding target tension (ZA*) of the discharge side and the reference tension (ZAR) of the discharge side.

5. The operating method according to claim 4, Its features are, The upper-level control device (14) pre-determines the sensitivity (SE) of the feed side and / or the sensitivity (SA) of the discharge side for the acquisition element (13).

6. The operating method according to claim 5, Its features are, The sensitivity (SE) of the feed side and / or the sensitivity (SA) of the discharge side are obtained by the upper-level control device (14) within the range of the pass scheme calculation under the evaluation of the rolling model (22), which describes the rolling process in the rolling stand (1) based on mathematical physics equations.

7. The operating method according to claim 1 or 2, Its features are, The upper-level control device (14) pre-sets the reference tension (ZER) on the feed side and / or the reference tension (ZAR) on the discharge side for the acquisition element (13).

8. The operating method according to claim 7, Its features are, The higher-level control device (14) -The initial basic target value (s0*), the target tension (ZE*) on the feed side, and the target tension (ZA*) on the discharge side are obtained based on the target thickness (d*) that the flat rolled piece (2) should have when it exits the rolling mill (1), the reference tension (ZER) on the feed side, and / or the reference tension (ZAR) on the discharge side. -The adjustment unit (7), which includes the position adjuster (6) and the acquisition element (13), is pre-given the initial basic target value (s0*), and -Pre-set the target tension (ZE*) on the feed side for the preceding tension adjuster (24), the preceding tension adjuster adjusts the actual tension (ZE) on the feed side to the target tension (ZE*) on the feed side, and / or pre-set the target tension (ZA*) on the discharge side for the following tension adjuster (25), the following tension adjuster adjusts the actual tension (ZA) on the discharge side to the target tension (ZA*) on the discharge side.

9. The operating method according to claim 1 or 2, Its features are, The composite position target value (s*) is obtained at least during the rolling of the middle section of the workpiece (2) using the correction value (δs2*) obtained with the actual rolling force (F).

10. The operating method according to claim 9, Its features are, The range of the obtained correction value (δs2*) takes into account the synthesized basic target value (s1*) in addition to the actual rolling force (F).

11. The operating method according to claim 1 or 2, Its features are, The composite position target value (s*) is obtained without utilizing the actual rolling force (F) at least during the rolling of the head (20) and / or foot (21) of the workpiece.

12. The operating method according to claim 1 or 2, Its features are, The synthesized position target value (s*) is obtained by taking into account the deviation between the thickness (d) of the rolled piece (2) detected on the discharge side of the rolling mill stand (1) and the target thickness (d*).

13. A control system for a rolling mill stand (1) for rolling a flat workpiece (2) made of metal, wherein the control system is configured by means of hardware blocks and / or software programming such that it implements the operating method according to any one of claims 1 to 12 during operation.

14. A rolling unit for rolling a flat workpiece (2) made of metal, wherein the rolling unit has a rolling mill stand (1) for rolling the flat workpiece (2) and a control system according to claim 13.

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