EP2475471A1

EP2475471A1 - Method and apparatus for compensating abnormal tensile loads in a strip of an acceleration-guided coiler drive

Info

Publication number: EP2475471A1
Application number: EP10754712A
Authority: EP
Inventors: Uwe Schäfer
Original assignee: Siemens AG
Current assignee: Primetals Technologies Germany GmbH
Priority date: 2009-09-09
Filing date: 2010-09-06
Publication date: 2012-07-18
Anticipated expiration: 2030-09-06
Also published as: WO2011029799A1; CN102740988B; DE102009040781A1; CN102740988A; WO2011029799A8; EP2475471B1

Abstract

The invention relates to a method for compensating abnormal tensile loads (S_St) in a strip (8) of an acceleration-guided coiler drive consisting of a driving motor (10, 12), a drive shaft (12, 14), and a coiler (4, 6). According to the invention, an actual acceleration (M_BM) of the driving motor (10, 12) is determined from a determined actual speed (n_M) of said driving motor (10, 12) and is compared with a desired acceleration (M_BM) of the driving motor, said desired acceleration (M_BM) being calculated from a predetermined motor-related desired acceleration (M ^* _Bu). A corrective variable (M_Kor) is determined from the difference between the actual and the desired acceleration, and said corrective variable (M_Kor) is superimposed on a generated desired moment (M ^* _M) of the motor in such a way that the determined difference between the actual and the desired acceleration becomes zero. Abnormal tensile loads are thus corrected, thereby preventing the strip from breaking.

Description

description

Method and apparatus for compensating for tensile stress disturbances in a belt of an accelerator-driven co-peat drive

The invention relates to a method for the compensation of tension disturbances in a belt of an accelerator-driven reel drive and to an apparatus for carrying out the method.

Reel drives operating in train-controlled mode, especially during acceleration phases, cause cable breaks, which can lead to band breaks.

From EP 0 477 422 AI a method and an apparatus for controlling a rolling mill reel is known, wherein a tension control is used. This train control has a draft regulator, which is fed with a determined difference in draft. This tension control is subordinated to a speed control. On the output side the subordinate Drehzahlre ^¬ gelung is linked to a drive unit of a reel. The ^¬ se drive unit of the reel has a motor, a Um ^¬ judge, current controller, etc. on. A ER- mittelte in the control path actual tensile force is compared with a predetermined target train ^¬ force and the difference of draw fed to the tension regulator. On the output side, a setpoint speed for the subordinate speed control is applied to the tension controller. By means of the subordinate speed control, a torque is generated for the turbofan engine.

With this control, a Abhaspelmotors a hochdyna ^¬ mix adaptation of a reel torque to a demanded train ^¬ force for achieving a tape having an approximately constant di- blocks is effected.

A disadvantage of this regulation is that a traction measuring device must be used. These traction Measuring device can not detect small tensile stresses. In addition, such Zugkraftmesseinrichtungen can not be used in the production of a film. In reel drives, which are operated in zuggesteuerten mode, it is possible that the tension in the strap as a result of an acceleration process breaks (change of rolling ^¬ effective degree). This can sag the tape. As a result of the tensile force reduction (no more load), the motor of the reel turns high, so that the sagging strip material is verrin ^¬ siege. As the engine speed increases, the tensile force in the belt material increases again. Depending on the tensile force ^¬ change, it may happen that the tape breaks. This problem could be solved so far only by improvements in the parameter setting or delay in the acceleration, which must be passed through ^¬ during commissioning. These optimizations are very system dependent. That is, for the solution of the problem, an expert for the commissioning of reel drives is needed.

The invention is based on the object of specifying a method for the compensation of tension disturbances in a belt of an acceleration-driven reel drive, wherein no tension control is used.

This object is achieved by the feature of claim 1 erfin ^¬ tion according to. This invention is based on the finding that Bandzug ^¬ disorders, which can also lead to ligament tear, cause disturbances in the engine acceleration.

According to the invention, these disturbances in the engine acceleration are determined by means of a measured engine speed. For this purpose, the engine speed is differentiated, whereby one receives a motor-related actual engine acceleration. This vorbe ^¬ agreed target acceleration is applied to a motor-related target Motor acceleration converted. As a result, by comparing the actual engine acceleration with the target engine acceleration, the magnitude of the disturbance in the engine acceleration can be determined. From this differential acceleration, a correction variable for a generated target engine torque is determined, which is superimposed on this target engine torque such that this differential acceleration is zero.

By means of this method according to the invention, tape tension disturbances can be compensated even without tape tension regulations. The advantages of the method according to the invention lie in the fact that reliable operation, in particular during acceleration phases, is ensured, that lengthy optimizations are eliminated and that less material is rolled into broke. With sta ^¬ bilen strip tensions better tolerances of a rolling stock can be achieved.

For a more detailed explanation of the invention, reference is made to the drawing, in which an embodiment of an apparatus for carrying out the method according to the invention is illustrated schematically.

1 shows a schematic diagram of a roll stand, which are assigned to both sides of two reels, the

2 shows a control circuit equivalent circuit diagram of

Schematic representation of FIG 1 with an apparatus for performing a method according to the invention, in which

FIG. 3 shows an interference signal in a diagram over time, which is shown in FIG

4 shows in a diagram over time a tensile stress, wherein in the

FIG 5 is a diagram over time an engine speed is shown in the

FIG 6 is an associated engine torque over time Darge ^¬ provides and the

FIG. 7 illustrates an associated engine acceleration over time. In FIG 1, 2 each with a roller, in particular a work roll, a rolling stand, not shown, with 4 and 6 respectively a reel and 8 denotes a between the two reels 4 and 6 moving belt. Each reel 4 or 6 has a drive motor 10 or 12, which is mechanically connected by means of a motor shaft 14 or 16 by means of an unspecified Darge ^¬ presented transmission with the reel 4 and 6 respectively. Each drive motor 10 or 12 has a tachogenerator 18 or 20, with which an actual value of its speed n _{M is} detected. Each drive motor 10 or 12 is associated with a ^¬ A device 22 or 24 that drives a function of prior ^¬ determined target values for a tension torque M _z of acceleration and M _B, respectively the associated motor drives 10 and 12 accordingly.

As a means 22 or 24, for example, a converter is provided, which also has an associated control and regulating device in addition to a power unit. This device 22 or 24 is also linked to an output of the tachogenerator 18 or 20 signal technology. In addition, FIG. 1 shows a compensation device 26 or 28 with which a method according to the invention is carried out. Since this compensation device 26 or 28 in an implemented embodiment is an integral part of the device 22 or 24, in particular its control and regulating device, this is represented by a broken line. This compensation device 26 or 28 is also connected to the output of the associated tachogenerator 18 and 20 signal technology. Further, this means 26 and 28, the predetermined target acceleration M _{B is} supplied.

Further, in this FIG 1 between the work rolls 2 and the reel 6, a portion 30 of the moving belt 8 Darge ^¬ provides, which sags as a result of a tensile break. Without a tension control, the reel 6 could tear the band 8 during an acceleration phase. The probability of a ^¬ like band break increases with decreasing thickness of the band 8 and is dependent on the material of this band 8. is the band to be processed a metal strip, such as aluminum, so the probability of a band break due to a tensile break is low. In any case, an area is created that is faulty and thus forms a committee. If the band 8 to edit a film strip, the probability of a ligament injury is ^¬ slump very high in consequence of a train.

In order to determine tensile stresses in the band 8 to be processed, tensile force measuring devices are used. These measuring devices are arranged in such a way to the belt 8, this strip 8 can exert a vorbe ^¬ agreed compressive force on this instrument. Depending dün ^¬ ner a band to be processed 8 is to be more sensitive Müs ^¬ sen this tensile force measurement instruments. Therefore, in the production of films tensile force measuring devices are not usable.

To get this problem under control, an expert is required, the optimized such pro ^production machine during commissioning. These optimizations can be implemented by parameter settings and / or delays in the acceleration. However, these optimizations are time-consuming and system-dependent. In all cases an experienced commissioning engineer is needed who can solve this problem with his expert knowledge.

In FIG 2, a control circuit equivalent circuit diagram of the driven reel 6 of FIG 1 is shown schematically. This equivalent circuit diagram has a number of sub-equivalent circuit diagrams which replace mechanical components of the reel drive according to FIG. These sub-equivalent circuits are labeled 32, 34, 36 and 38. The Teilersatzschalt ^¬ picture 32 represents the control engineering equivalent circuit diagram of the drive motor 12, the sub-equivalent circuit 34 controls the drive shaft 16 with a gearbox, while the partial equivalent circuit diagram 36, the wound tape 8 and the sub-equivalent circuit diagram 38, the conveyor belt 8 represent each control technology. The control engineering equivalent circuit 32 of the Antriebsmo ^¬ gate 12 has a PTi gate 40, a comparator 42 and an I-member 44. The time constant of the PTi element 40 is the equivalent time constant T _{e of} the torque control, whereas the time constant of the I element 44 is the motor time constant T _M. At the output of the PTi-member 40 is a signal for the internal engine torque M _M , wherein at the output of the I-member 44, a signal ^¬ nal for the engine speed n _M is pending. At the inverting input of the comparator 42 is a signal for a moment of the drive shaft 16, which is ver ^¬ compared with the internal engine torque M _M ^¬ . A detected difference is the acceleration Motorbe ^¬ M _B M of the drive motor 12. From this Motorbe acceleration ^¬ M _B M is an actual engine rotation speed generated by the I-member 44 n _M.

The sub-equivalent circuit diagram 34 has, in addition to an I-element 46, a P-element 48, which are connected by signal technology in series. The series connection of these two control elements 46 and 48 simplifies the drive shaft 16 with a transmission. At the output of the P-member 48 is a signal Sig ^¬ signal for the shaft torque M _w , which is fed back inter alia to the comparator 42.

This shaft torque M _w is also supplied to the sub-equivalent circuit diagram 36, which represents the reel 4 or 6 with wound-up belt 8. This sub-equivalent circuit 36 has only one I-member 50. At the output of this I-element 50 is a signal for the reel speed n _H on. The I element 50 has as a time constant the reel time constant T _H.

The partial equivalent circuit 38, the control technology is the transported tape 8, a functional member 52, whose function is v depending from at least the decrease or Aufwickelge ^¬ speed and referred to as a result of the current train F _z, as well as tensile stress, provides the band , which is multiplied by a multiplier 54 with a band radius R _H. The generated product is fed back to a comparator 56, whose output is connected to the input gear of the I-member 50 is connected. At the non-inverting input of the comparator 56 is the wave moment MW. The reel speed n _H present at the output of the I element 50 is multiplied by the constant R _H by means of a further multiplier 58, so that a value for the unwinding or winding speed v is present at the output of the multiplier 58.

As already mentioned, reel drives are operated in train-controlled mode. For this purpose, a desired value for a tensile moments M _z and for an acceleration M _{B are} required in each case. These setpoints M _z and M _B are superimposed by an adder 60 via ^¬ and the result is fed to a subsequent adder 62nd At the inverting input of this adder 62 there is a correction quantity M _Kor , which is generated by the compensation device 26. By means of the adder 62 is a motor torque setpoint M _M with the determined correction value

M _Kor overlaid.

The compensation device 26, which carries out the method according to the invention, has a ΡΪΊ-element 64, a DTi element

66, a PID gate 68 and a comparator 70 on. At the input of the DTi member 66 is at the output of the I-member 44 of the control member 32 generated actual engine speed n _{M is} . By means of the DTi element 66, an associated actual engine acceleration M _B M is generated from this actual engine speed n _M. This actual engine acceleration M _B M is compared with a desired engine acceleration M _BM , which is present at the output of the ΡΪΊ-member 64. At the entrance of this ΡΪΊ-member 64 is a converted to motor ^¬ size setpoint acceleration M _Bu . This desired acceleration M _Bu is determined by means of a conversion device 72 from a predetermined desired acceleration M _B. As a conversion device 72 may be provided in the simplest case, a constant. The method according to the invention for compensating for tensile stress disturbances in a belt 8 is based on the knowledge that belt tension disturbances are noticeable in disturbances of the actual engine acceleration M _BM . Since a reel drive 4 or 6 im- If the vehicle is driven in an accelerated manner, the inventor came up with the idea that a correction variable could be determined from a determined difference between the setpoint and actual engine acceleration M _BM and M _BM

M _Kor derive, with this disturbance in the band 8 can be at least damped or corrected.

A measure of the reel drive that is needed already for the Be ^¬ drove the reel drive, the motor rotation speed n _M ^¬. This engine speed n _M is determined by means of the tachogenerator 18 or 20. In order to generate an associated actual engine acceleration M _B M from this actual engine speed n _M , the determined actual engine speed n _{M is} differentiated. This actual engine acceleration M _B M is the current acceleration performed by the reel motor 4 or 6. A setpoint acceleration M _B for the reel drive is available. This acceleration Sollbe ^¬ M _B must first be converted to a motor-related target acceleration M _Bu means of Conversion means 72nd This converted value M _Bu becomes the

PTi element 64 of the compensation device 26 supplied, which has as a time constant, the equivalent time constant Te of Momentenre ^¬ gelung. At the output of this ΡΪΊ-member 64 is the target engine acceleration M _BM . The actual engine acceleration M _BM determined from the engine speed n _M is compared with this desired engine acceleration M _BM . From a determined difference acceleration, a correction quantity M _{Kor is} determined by means of the PID member 68, which is superimposed on the desired engine torque M _M such that the determined differential acceleration becomes zero. In the figures 3 to 7 are waveforms each in one

Diagram over the time t shown, wherein in each diagram these waveforms without inventive method (a) and with method (b) according to the invention are shown. Tension disturbance in case (a):

If a Bandzugstörung, characterized by a sturgeon ^¬ size S _st in the graph of FIG 3, so the train F _z breaks and swings slightly attenuated (Fig 4). The engine speed n _M follows this oscillation (FIG. 5). The engine torque M _M remains unchanged as specified (FIG. 6). The motor acceleration M _BM associated with the engine speed n _M is shown in FIG. 7, which has several overshoots which decay over time t.

Tension disturbance in case (b):

In this case, a disturbance S _S t also occurs (FIG. 3), which ensures that the train F _z breaks down. The course of the engine torque M _M according to FIG. 6 shows that it is no longer constant as in case (a). This temporal Ver ^¬ change of the engine torque M _M is caused by a Cor ^¬ rekturgröße M _KO r, which is evidence with the inventive method it ^¬. This correction quantity M _Kor is superimposed on the desired engine torque M _{M in} such a way that resulting fluctuations in the engine acceleration M _{BM are} attenuated or compensated. By damping the motor acceleration M _BM , no increased tensile stresses occur as in case (a) more (FIG. 5). Thus, tension disturbances no longer lead to a band break. This ensures safe operation, especially in acceleration phases of a reel drive. This is done with relatively simple optimizations. It can be shown that this method is robust in the parameter setting. In addition, productivity is increased by this method according to the invention. That is, less material is processed into rejects. Furthermore, achieve stable strip tension better thickness tolerances of a rolling stock.

Claims

claims

1. Method for compensation of tension disturbances

(Sst) i ⁿ a belt (8) of an accelerator-driven hackelantriebs, consisting of a drive motor (10,12), a drive shaft (12,14) and a reel (4,6), wherein from a determined actual engine speed ( n _M) of the drive motor (10,12), an actual engine acceleration (M _BM) of this motor (10,12) he ^¬ averages is that (with a desired engine acceleration M _BM), which (from a predetermined engine-related target acceleration M _Bu ) is calculated, is compared, being determined from a Dif ^¬ ferenz acceleration correction variable (M _Cor), which is a generated set engine torque (M _M) is superimposed such that the differential acceleration becomes zero.

2. The method according to claim 1, characterized in that for determining an actual engine acceleration ^¬ (M _BM ) of the drive motor (10,12), the determined actual engine speed (n _M ) of the drive motor (10,12) is differentiated.

3. The method according to claim 1, characterized in that the engine-related target acceleration (M _B * _u ) is smoothed.

4. The method according to claim 1, characterized in that for determining a correction quantity (M _Cor) multiplying the determined difference acceleration with a comparison strengthening factor, integrated and differentiated is ^¬ sheet.

5. Apparatus for compensating for tension disturbances in a belt (8) of an acceleration-driven reel drive, to which a control device (22, 24) delivers an actuating signal, said reel drive comprising a drive motor (10, 12) with tachogenerator (18, 20) Drive shaft (14,16) and a reel (4,6), wherein the control device (22,24) a ne compensation device (26,28) is assigned to the ^¬ sen an input a target acceleration (M _B ) is pending and whose other input is connected to an output of the tachogenerator (18,20), and wherein an output of Kompen ^¬ sations -E device (26,28) with an input of the control device (22,24) is connected.

6. Device according to claim 5, characterized in that the compensation device (26, 28) is integrated in the control device (22, 24).

7. Device according to claim 5 or 6, characterized in that the control device (22, 24) is a microprocessor.