EP0018555B1 - Control device for a roller stand - Google Patents

Description

The invention relates to a control arrangement for a roller carrier, which is known from DE-A-2 732 644. There, a control arrangement for a roller carrier is described, in which a web with a predetermined web tension is unwound from a rotatably mounted roller, the roller being assigned an electromotive drive or braking device with a speed controller and a computer that continuously optimizes control parameters for the speed controller the route parameters determined.

Control arrangements for roller carriers with fixed control parameters of the speed controller work unsatisfactorily since the time constant of the route changes within wide limits during an unwinding process. The change in the time constant is caused by the large decrease in the moment of inertia of the roll with decreasing diameter. DE-A-2 732 644 provides for a continuous determination of optimized control parameters as a function of the changing route parameters. The current moment of inertia is determined by the computer from input variables for the web width and the specific material density, as well as from the current radius of the roll. The web width could also be determined by a mechanical measuring device.

The present invention has for its object to develop the control arrangement for a roll carrier according to DE-A-2 732 644 so that an input or detection of the specific density of the web material and the web width is no longer necessary.

According to the invention, this object is achieved in that the computer determines the optimized controller gain and / or the optimized readjustment time of the speed controller from an initial value of its moment of inertia determined during startup of the new roll and the current radius of the roll during unwinding.

In the control arrangement according to the invention, input devices or measuring devices for the specific material density and the web width are no longer required. The optimized controller parameters are determined completely automatically from the changing route parameters. In addition to reducing the design effort, this also provides greater security against incorrect operation.

According to a preferred embodiment of the invention in a roller carrier with a belt drive and an electrical machine assigned to the belt drive, a circuit arrangement is provided which determines the initial value of the moment of inertia of the roll from measured values for the synchronous speed, for the time until the synchronous speed is reached, for the Drive torque of the electrical machine and for the initial value of the roller radius, as well as determined values for the moment of inertia of the electrical machine and the radius of the drive rollers of the belt drive.

In the case of a roller carrier with an electric direct drive, a circuit arrangement is provided according to a further preferred embodiment of the invention, which determines the initial value of the moment of inertia of the roller from measured values for the synchronous speed for the time until the synchronous speed is reached, for the drive torque of the direct drive and for one predetermined value for the moment of inertia of the direct drive is determined.

• Fig. 1 einen Rollenträger mit einem Gurtantrieb in der normalen Abwickelposition,
• Fig. 2 den Rollenträger mit Gurtantrieb in einer Zwischenposition beim Einschwenken in die Klebeposition,
• Fig. 3 den Rollenträger mit Gurtantrieb in der Klebeposition,
• Fig. 4 eine schematische Darstellung einer Meßanordnung zur Erfassung des Anfangswertes und des Momentanwertes des Rollenradius,
• Fig. 5 eine Schaltungsanordnung zur Ermittlung des Anfangswertes des Trägheitsmoments einer Rolle unter einem Gurtantrieb,
• Fig. 6 einen Rollenträger mit einem Direktantrieb in der Klebeposition,
• Fig. 7'eine Schaltungsanordnung zur Ermittlung des Anfangswertes des Trägheitsmoments einer Rolle bei einem Direktantrieb,
• Fig. 8 ein Ausführungsbeispiel eines Reglers mit optimierbarer Reglerverstärkung.

Embodiments of the invention are shown in the accompanying drawings and are explained in more detail below. It shows

• 1 is a roller carrier with a belt drive in the normal unwinding position,
• 2 the roller carrier with belt drive in an intermediate position when swiveling into the gluing position,
• 3 the roller carrier with belt drive in the gluing position,
• 4 shows a schematic representation of a measuring arrangement for detecting the initial value and the instantaneous value of the roller radius,
• 5 shows a circuit arrangement for determining the initial value of the moment of inertia of a roller under a belt drive,
• 6 shows a roller carrier with a direct drive in the adhesive position,
• 7 'shows a circuit arrangement for determining the initial value of the moment of inertia of a roller in a direct drive,
• 8 shows an embodiment of a controller with optimizable controller gain.

1 to 3 show a two-armed roller carrier 3 with a belt drive 4, which can be pivoted from its normal unwinding position (FIG. 1) by a swivel drive, not shown, via an intermediate position (FIG. 2) into the adhesive position (FIG. 3) . Such roller carriers are designed with two arms or three arms. The running roll (winding) is rotatably mounted on one arm of the roll carrier 3. The running reel is identified by reference number 2, the individual stages of the reel being indicated by 2a, 2b, 2c during the unwinding process. A web B is drawn off from the roll 2 in the direction of the arrow, for example a paper web which is fed to a group of trains, also not shown, via deflection rollers (not shown). The new roller 1 is already on the other arm of the roller carrier 3 instructed.

In the illustration in FIG. 1, the running roller 2a runs in the developed position of the roller carrier 3 under the belt drive 4. The belt drive 4 is assigned an electromotive drive with an electrical machine 5, which is fed by a converter 6. The converter 6 is controlled by a control set 33 with ignition pulses, the control voltage of which is formed by a current regulator 32, to which a comparator 31 is connected upstream on the input side. The electrical machine 5 is coupled to a tachometer generator 7 for generating a tacho voltage proportional to the actual speed value.

The web B should enter the downstream processing machine with a constant web tension, for example a printing machine. The web tension is controlled by the belt drive 4. The belt drive 4 is controlled by a control device with a position controller 8, a speed controller 13 and the subordinate current controller 32 as a function of the position of a dancer roller 9, for example in such a way that the dancer roller 9 is in the middle their positioning range remains. The dancer roller 9 is weight-loaded or receives a pneumatic preload. An actual value for the position of the dancer roller 9 is tapped at a schematically represented potentiometer 14 and compared in a comparator 10 with a position setpoint by an adjusting device 11. The position difference controls the position controller 8, the output voltage of which forms the speed setpoint for the speed controller 13. The setpoint speed value is compared in a further comparator 12 with the tachometer voltage of the tachometer generator 7 as the actual speed value, which is connected to the comparator 12 via the closed switching contact 23. The control difference formed in the comparator 12 controls the speed controller 13, the output signal of which is supplied to the comparator 31 as a current setpoint via the switch contacts of switches 25 and 26 in the position shown. In the comparator 31, the current setpoint is compared with the actual current value detected by a current measuring transducer 34 and fed to the current controller 32 as a control difference. The output voltage of the current regulator 32 forms the control voltage for the control set 33 of the converter 6. Thus, the output voltage of the speed regulator 13 determines the speed of the electrical machine 5 and, via the belt drive 4, the speed of the roller 2a.

• a Optimierungsfaktor für die Reglerverstärkung
• A wickelspezifischer Summand nach Gl. (10)
• d Index für einen Direktantrieb
• g Index für einen Gurtantrieb
• l_a Ankerstrom
• J auf den Antrieb bezogenes Trägheitsmoment (J_o = Anfangswert)
• J_M Trägheitsmoment des Antriebs
• J_w Trägheitsmoment der Rolle (J_wo = Anfangswert)
• k_a Konstanter Faktor nach Gl. (3)
• k_d spezifischer Faktor bei einem Direktantrieb nach Gl. (16d)
• kg spezifischer Faktor bei einem Gurtantrieb nach Gl. (11g)
• n_s synchrone Drehzahl
• n_" Nenndrehzahl
• M_k konstantes Antriebsmoment
• r Radius der Antriebsrollen des Gurtantriebes
• R_w Radius der Rolle (R_wo = Anfangswert)
• T, Nachstellzeit des Reglers
• Ts Zeitkonstante der Regelstrecke
• Tso Anfangswert von T_s
• T_u Verzugszeit der Regelstrecke
• t_s Zeit bis zum Erreichen von n_s
• V_K Kreisverstärkung
• V_R Reglerverstärkung
• V_s Streckenverstärkung

The problem with such a speed control lies in the considerable changes in the properties of the controlled system during the unwinding process. During the unwinding process, for example, the diameter of the roll can decrease from 1 m to 0.1 m. In addition, depending on the production program, webs with different widths can be used in a range of approximately 1: 4. The specific weight of the web material used can also vary. Accordingly, the mass of the roll can change over a very wide range. However, the mass of the roller has a significant share in the total moment of inertia of the controlled system. The parameters mentioned can change the moment of inertia of the roller in a range greater than 1: 1000. In the case of a speed control, the control parameters of the speed controller 13 are usually set such that the stability conditions are met in the entire control range. With such fixed control parameters, however, the speed control cannot work optimally in the entire control range, since the distance parameters change over a very wide range due to the large differences in the moment of inertia of the roller. Control parameters for the speed controller 13, which are optimized by a computing device 50, are therefore continuously determined from the route parameters and the speed controller is set accordingly. The sizes listed below are used in the following explanations:

• a Optimization factor for the controller gain
• A winding-specific summand according to Eq. (10)
• d Index for a direct drive
• g Belt drive index
• l _a armature current
• J moment of inertia related to the drive (J _o = initial value)
• J _M moment of inertia of the drive
• J _w moment of inertia of the roll (J _wo = initial value)
• k _a constant factor according to Eq. (3)
• k _d specific factor for a direct drive according to Eq. (16d)
• kg specific factor for a belt drive according to Eq. (11g)
• n _s synchronous speed
• n _" nominal speed
• M _k constant drive torque
• r Radius of the drive rollers of the belt drive
• R _w radius of the roll (R _wo = initial value)
• T, reset time of the controller
• Ts time constant of the controlled system
• Tso initial value of T _s
• T _u delay time of the controlled system
• t _s Time to reach n _s
• V _K loop gain
• V _R controller gain
• V _{s path} gain

Numerous optimization regulations are known for the cheapest setting of control processes, which are described, for example, in Winfried Oppelt, “Small Manual of Technical Control Processes”, 3rd edition, 1960, pages 418 to 433, in particular page 427. A distinction must be made in the most favorable setting of a control loop whether it should be optimized for the correction of disturbance variables or for changing the reference variable, because a control process has to be set differently, depending on whether it should compensate for a disturbance as quickly as possible or whether it should follow a change in the reference variable as faithfully as possible. A further distinction must be made as to whether an aperiodic control process with the shortest duration is required or whether a certain overshoot is permitted, for example 20% overshoot with the shortest oscillation period. Finally, it must also be considered whether the controller used is a P controller, a PI controller or a PID controller.

The following explanations are given by way of example for a PI controller which is intended to compensate for a malfunction as quickly as possible, with 20% overshoot with the shortest oscillation period being permitted. The optimization factors from Chien, Hrones, Reswick (cited above p. 427) are used.

wobei der Optimierungsfaktor a für das gewünschte Regelverhalten zu 0,7 gewählt werden kann.The optimization condition (1) generally applies to the optimized loop gain:

the optimization factor a for the desired control behavior can be chosen to be 0.7.

The delay time T _{u of} the line is essentially the sum of the armature time constant of the electrical machine 5 and the dead time of the converter 6. These times are independent of the moment of inertia of the roller. In this view, the delay time T _u can be regarded as approximately constant.

The loop gain V _{K of} the control loop is the product of the controller gain V _R and the section gain V _s . The system gain Vs is the product of all individual gains, for example the gains of the sensors, the subordinate controllers, the converter and the drive. The distance gain V _s is approximately independent of the moment of inertia of the roller and can therefore also be regarded as constant. The loop gain V _K is the product of the controller gain V _n and the distance gain V _s according to Eq. (2):

If you put in Eq. (2) the optimization criterion (1) for the loop gain, we get Eq. (2.1) for the optimized controller gain V _R :

so nimmt die GI (2.1) die Form (2.2) an: .

One recognizes from Eq. (2.1) that the optimized controller gain V _{R is} directly proportional to the time constant T _{s of} the controlled system, since the optimization factor a, the delay time T _{u of} the controlled system and the system gain V _{s are} approximately constant. If a constant factor k _{a is carried out} according to Eq. (3) a:,

the GI (2.1) takes the form (2.2):.

The problem now is that the continuously changing time constant T _{s of} the system is required to continuously determine the optimized controller gain V _R. Because the change in Time constant T _{s w} of the track substantially on the change in the moment of inertia J of the roller is determined, is carried out according to the invention a continuous determination of the moment of inertia J _w of the roll from an initial value J o _w and the respective radius Rw. We are looking for function (4):

To determine the parameters of the controlled system, which essentially contains the electrical machine 5 with the role as a permanently coupled load, the time can be used to accelerate a new role with a constant torque from standstill to a certain speed .

Assuming a substantially linear ramp _k of a new roll at a predetermined constant driving torque M, preferably to the nominal torque, from standstill to a predetermined rotational speed _S n refers to the period t _s, which is to reach the predetermined speed _S N needed the Eq. (5):

The Eq. (5) can be converted from the initial value J _o of the total moment of inertia related to the drive to Eq. (5.1):

Eq. Applies to a roller driven by a belt drive (index g). (6 g)

For the initial value J _{wo of} the moment of inertia of the roll, Eq. (6 g) to Eq. (6.1 g) are formed:

If you put Eq. (5.1) in Eq. (6.1 g), we get Eq. (6.2 g):

• Sobald der Durchmesser der Rolle 2 einen bestimmten Wert unterschreitet, wird in der Darstellung der Fig. der Gurtantrieb 4 von der Rolle 2b abgehoben. Der Arm des Rollenträgers 3 wird geschwenkt. Die Regelung der Bahnspannung der ablaufenden Bahn B erfolgt jetzt über elektrische Bremseinrichtungen, beispielsweise über die schematisch dargestellten Induktionsbremsen 17 bzw. 18. Die Induktionsbremsen 17 bzw. 18 sind mit den Rollenachsen und mit Tachogeneratoren 19 bzw. 20 gekuppelt. Durch die Stellung der Schaltkontakte der Umschalter 27 bzw. 28 wird festgelegt, daß die der Rolle 2b zugeordnete Induktionsbremse 17 zusammen mit dem zugehörigen Tachogenerator 19 wirksam wird, wenn der Gurtantrieb 4 von der Rolle 2b abgehoben wird. In der normalen Abwickelposition sind die Induktionsbremsen 17 bzw. 18 nicht wirksam. Daher befinden sich in der Darstellung der Fig. 1 die Schaltkontakte der Umschalter 27 und 28 in einer Mittelstellung, so daß keine der beiden Induktionsbremsen 17, 18 wirksam ist und die Tachospannungen der Tachogeneratoren 19, 20 nicht weiterverarbeitet werden. Zum besseren Verständnis sind in Fig. 2 und Fig. 3 die Umschalter 27 und 28 derart vereinfacht dargestellt, daß die Verbindungen zur jeweils nicht wirksamen Induktionsbremse und zum Tachogenerator weggelassen sind.

The initial value J _{wo of} the moment of inertia of the roll can thus be calculated if the values on the right side of Eq. (6.2) knows. Before the determination of these values and thus the determination of the initial value of the moment of inertia of the roll is discussed in detail, the sequence of a roll change is first explained using FIGS. 2 and 3:

• As soon as the diameter of the roller 2 falls below a certain value, the belt drive 4 is lifted off the roller 2b in the illustration in FIG. The arm of the roller carrier 3 is pivoted. The regulation of the web tension of the running web B now takes place via electrical braking devices, for example via the schematically illustrated induction brakes 17 and 18. The induction brakes 17 and 18 are coupled to the roller axes and to tachogenerators 19 and 20. The position of the switching contacts of the changeover switches 27 and 28 determines that the induction brake 17 assigned to the roller 2b, together with the associated tachometer generator 19, takes effect when the belt drive 4 is lifted off the roller 2b. In the normal unwinding position, the induction brakes 17 and 18 are not effective. 1, the switch contacts of the changeover switches 27 and 28 are in a central position, so that neither of the two induction brakes 17, 18 is effective and the tachometer voltages of the tachometer generators 19, 20 are not further processed. For better understanding, the changeover switches 27 and 28 are shown in simplified form in FIGS. 2 and 3 in such a way that the connections to the respectively ineffective induction brake and to the tachometer generator are omitted.

FIG. 1 shows the roller carrier in an intermediate position during the counter-clockwise pivoting process from the unwinding position shown in FIG. 1 to the adhesive position shown in FIG. 3. The belt drive 4 was lifted off and at the same time the switching contacts of the switching devices were reversed into the switching positions shown. The speed control of the roller 2b no longer takes place via the belt drive, but via the induction brake 17. The actual position value from the dancer roller 9 is tapped at the potentiometer 14 and compared in the comparator 10 with the position setpoint by the setting device 11. The The output voltage of the position controller 8 forms the speed setpoint, which is compared in the further comparator 12 with an actual speed value. This actual speed value is supplied in this position of the roller carrier via the closed switching contact 24 from the tachometer generator 19, which is coupled to the roller 2b. The output voltage of the speed controller 13 is supplied to the control unit 36 of a further converter 16 via the switching contact of the changeover switch 25 and via an adapter as the control voltage. The converter 16 is the actuator for the induction brake 17, which acts on the roller 2b.

Fig. 3 shows the roll carrier 3 in the gluing position, in which the new roll 1 is glued to the running web B on the fly. This process is described in detail, for example, in DE-A-2 619 236. The roll 2c has run down to the residual roll diameter. The induction brake 17 is still engaged. The new roll 1 is located under the belt drive 4. The belt drive 4 is lowered onto the new roll 1.

So that the new roll 1 can be glued to the web B on the fly, the peripheral speed of the new roll 1 must first match the web speed. In order to establish this correspondence, a speed controller 30 and an upstream ramp generator 37 are provided. The run-up controller 37, which can be designed, for example, as an integrator with a downstream limiting element, leads the setpoint for the speed controller 30 according to a predetermined ramp function up to the synchronous speed n _s , at which the peripheral speed of the new roll matches the web speed. The slope of the ramp function is selected so that the electrical machine 5 is operated approximately with a constant armature current in this run-up phase. To form a tachometer voltage corresponding to the synchronous speed n _s , a tachometer generator 21 is provided which is driven by the running web B via a friction wheel 22. The tachometer voltage of the tachometer generator 21 is thus a measure of the web speed. The required synchronous speed n _s is in a fixed relationship since the peripheral speed of the new roll corresponds to the speed of the belt strap of the belt drive 4, which in turn is known via the speed of the electrical machine 5 and the transmission ratio of the belt drive.

The output voltage of the ramp generator 37 is compared with the tachometer voltage of the tachometer generator 7 in a comparator 29. The control difference controls the speed controller 30. The output voltage of the speed controller 30 is used via the changeover switch 26 as a setpoint for the lower-level current controller 32. The new role is thus accelerated to the synchronous speed n _s via the speed control with the speed controller 30 and the subordinate current controller 32, the ramp-function generator 37 ensuring a smooth start-up with a largely constant armature current and thus also a largely constant drive torque.

If the peripheral speed of the new roll 1 corresponds to the web speed of the running web B, the gluing process is carried out by pressing the running web B against the new roll 1 provided with an adhesive flag 15 by a brush roller 40. Behind the gluing point is the end of the old roll Cut through the sheet of a fly knife 41. Immediately after the gluing process, the belt drive 4 takes over the speed control of the new roll. To do this, it is generally necessary to slow down the new roller. The belt drive with the electrical machine 5 and the power converter 6 is therefore designed as a 4-quadrant drive, preferably with a power converter in countercurrent connection free of circulating current. The transition of the control of the belt drive from the acceleration of the new roll to the synchronous speed n _s , at which the peripheral speed of the new roll 1 takes over with the web speed of the running roll B, to the speed control with regard to a constant web tension, is achieved in that the Switch contacts of the switching devices can be reversed into the position shown in FIG. 1. The remaining roll 2c is now pulled off the axis of the roller carrier and a new roller is pushed onto this axis. _-

• Fig. 4 zeigt schematisch die meßtechnische Ermittlung des Radius der neuen Rolle 1 und des Radius der ablaufenden Rolle 2. Die Position des Rollenträgers entspricht der Fig. 3. Es sind lediglich diejenigen Elemente dargestellt, die zur Erfassung der Radien erforderlich sind. Auf einer auf der Achse der Rolle 2 befestigten Scheibe ist eine Markierung 51 angebracht, die von einer Sonde 52 erkannt wird. Die Sonde 52 erzeugt bei jeder Umdrehung der Rolle 2 einen Impuls beim Vorbeilauf der Markierung 51.

The ramp-up of the new role 1 is used to solve the GI. (6.2) determine the required values. The determination of the radius is first described using FIG. 4:

• FIG. 4 shows schematically the measurement of the radius of the new roll 1 and the radius of the running roll 2. The position of the roll carrier corresponds to that of FIG. A marking 51, which is recognized by a probe 52, is attached to a disk fastened on the axis of the roller 2. The probe 52 generates a pulse as the mark 51 passes each revolution of the roller 2.

The web B drives a digital pulse generator 54 via a friction wheel 53, the pulse disk of which bears a larger number of markings which are scanned by a further probe 55. The probe 55 thus generates a predetermined number of pulses for a certain web length. The pulses of the probe 55 are counted by a counter 60. The counting device is released by a first pulse from the probe 52 and counts the pulses from the probe 55 until a second pulse from the probe 52 arrives. The number of pulses of the probe 55 between two successive pulses of the probe 52 is a measure of the web length drawn off during one revolution of the roll 2 and thus also a measure of the radius R _{w of} the roll 2.

A further marking 56, which is recognized by a further probe 57, is attached to a disk fastened on the axis of the new roller 1. Provided that the path speed of the running path B coincides with the peripheral speed of the new roll, the radius Rwo of the new roll 1 can be determined in a further counting device 61 by the number of pulses of the probe 55 between two pulses of the probe 57 be counted. The determination of the radius Rwo is thus carried out by closing a switch 58 by means of a corresponding command when the synchronous run is reached at the end of starting up the new roller 1. The counting device 61 now counts the pulses of the probe 55 during one revolution of the new roller 1. The number of pulses of the probe 55 is directly a measure of the radius R _where the new roller 1.

In Eq. (6.2g) the radius r of the drive rollers of the belt drive is still required. This radius is known and can be predefined.

Furthermore, the synchronous speed n _{s is} required, at which the speed of the running web B coincides with the peripheral speed of the new roll 1. The synchronous speed n _s can be determined from the speed of the electrical machine 5 detected by the tachometer generator 7, taking into account the transmission ratio r / Rw _o or can be determined directly from the tachometer voltage of the tachometer generator 20.

Furthermore, the time t _s that the drive needs to start the new roller from a standstill to the synchronous speed n _s at a fixed predetermined torque is recorded.

In order to determine the predetermined drive torque, the electrical machine 5 can in principle be regulated to a constant torque. For the present case, however, it is sufficient if the moment of the machine 5 is considered to be directly proportional to the armature current. It is then easily possible to regulate the armature current by configuring the ramp generator 37 accordingly.

The moment of inertia J _{M of} the electrical machine 5 'is known and can be assumed to be constant. It can be determined during commissioning ..

• Der Gurtantrieb 4 wird auf die neue Rolle 1 abgesenkt. Die elektrische Maschine 5 wird eingeschaltet und mit konstantem Strom, vorzugsweise Nennstrom, bis zum Erreichen der Synchrondrehzahl n_s hochgefahren. Sobald die Synchrondrehzahl n_s erreicht ist, wird diese bestimmt und die benötigte Zeit t_s gemessen. Jetzt wird auch der Radius R_wo der neuen Rolle 1 bestimmt. Bekannt ist weiterhin der vorgegebene Wert des Ankerstromes l_a, das Trägheitsmoment J_M der Maschine 5' und der Radius r der Antriebsrollen des Gurtantriebes 4. Hieraus läßt sich nach Gl. (6.2g) unmittelbar der Anfangswert J_wo des Trägheitsmoments der Rolle 1 unter einem Gurtantrieb 4 berechnen.
• Fig.5 zeigt ein Ausführungsbeispiel einer Schaltungsanordnung 80 zur Ermittlung des Anfangswertes J_wo der Rolle unter einem Gurtantrieb 4. Die Schaltungsanordnung 80 enthält einen Integrator 81, der zu Beginn des Hochlaufs der neuen Rolle über einen Schalter 82 an ein Potentiometer 83 angeschlossen wird. Der von einer Kommandostufe 92 betätigte Schalter 82 wird wieder geöffnet, wenn die Rolle die synchrone Drehzahl erreicht hat. Dies läßt sich aus einer Überwachung der Regeldifferenz ermitteln, die den Drehzahlregler 30 aussteuert. Der Integrator 81 integriert somit eine konstante Eingangsspannung so lange, bis die synchrone Drehzahl erreicht wird. Die Ausgangsspannung des Integrators 81 ist somit ein Maß für die Hochlaufzeit ts.

The initial value J _{wo of} the moment of inertia of the new roller 1 is thus determined as follows:

• The belt drive 4 is lowered onto the new reel 1. The electric machine 5 is switched on and started up with a constant current, preferably nominal current, until the synchronous speed n _{s is reached} . As soon as the synchronous speed n _{s is} reached, this is determined and the required time t _{s is} measured. Now the radius R _where the new roll 1 is determined. Also known is the predetermined value of the armature current I _a , the moment of inertia J _{M of} the machine 5 'and the radius r of the drive rollers of the belt drive 4. (6.2g) immediately calculate the initial value J _{wo of} the moment of inertia of the roller 1 under a belt drive 4.
• 5 shows an embodiment of a circuit arrangement 80 for determining the initial value J _where the reel under a belt drive 4. The circuit arrangement 80 contains an integrator 81 which is connected to a potentiometer 83 via a switch 82 at the start of the start-up of the new reel. The switch 82 operated by a command stage 92 is opened again when the roller has reached the synchronous speed. This can be determined by monitoring the control difference, which controls the speed controller 30. The integrator 81 thus integrates a constant input voltage until the synchronous speed is reached. The output voltage of the integrator 81 is thus a measure of the ramp-up time ts.

A divider 84 is connected downstream of the integrator 81, the dividend input of which is connected to the output of the integrator 81 and the divider input of which is connected to the tachometer generator 7. The output of the division element 84 is connected to the one input of a multiplier 85, the second input of which is connected to a voltage representing the armature current I _{a of} the electrical machine 5 '. The armature current is a measure of the drive torque of the machine 5. In order to take the proportionality factors into account, the measuring voltage for the armature current is conducted via a potentiometer 86. The output voltage of the multiplier 85 is compared in a comparator 87 with a voltage which is set to a value corresponding to the moment of inertia J _{M of} the machine 5, for example on a further potentiometer 88. The output voltage of the comparator 87 is fed to the one input of a multiplier 89 whose other input is supplied with a voltage that corresponds to the value (R _{wo /} r) ² . This voltage can be tapped, for example, at a potentiometer 90 which is at a voltage determined by the counting device 61 or whose tap can be changed by the counting device 61. The output voltage of the multiplier 89 is a measure of the desired initial value J _{wo of} the moment of inertia of a roller under a belt drive. It is fed to the computer 50 via a switch 91. The switch 91 is closed by the command stage 92 as soon as the synchronous speed has been reached, and is opened again immediately after the takeover of the initial value J _where the moment of inertia of the roller.

First, the initial value T is required _as the time constant of the controlled system. Taken under the condition of a linear ramp-up T results _as according to Eq. (7):

From this follows the initial value V _{RO of} the optimized controller gain according to Eq. (2.3) from the relationship (2.2) to:

The time constant T _{s of} the path, which changes continuously with decreasing radius R _w, can be determined using the relationship (8):

For the moment of inertia J, Eq. (6.3g) the GI shown in general form. (6g):

If the relationship (8) is solved according to T _S and Eq. (6.3g), we get Eq. (8.1 g) for a reel with belt drive:

nimmt die Gl. (8.l g) die Form (8.2g) an:

Since the relationship (9) applies to the moment of inertia J _{w of} the roller:

takes the Eq. (8.lg) the form (8.2g) to:

und einen bei einem Gurtantrieb spezifischen Faktor kg

ein, so nimmt die Gl. (8.2g) die Form (8.3g) an:

Equation (8.2g) is the function (4) we are looking for for a reel with belt drive. If you carry out a winding-specific summand

and a factor kg specific for a belt drive

one, so Eq. (8.2g) the form (8.3g):

Eq. Applies to the optimized controller gain V _{Rg of} a speed controller for a reel with belt drive. (2.4g):

The Eq. (2.4g) is continuously calculated by the computing device 50 and the optimized controller gain is predefined for the speed controller 13.

With regard to the readjustment time T _{l of} a PI controller, the optimization condition (12) applies for a good control of disturbance variables with a 20% overshoot:

Since - as already mentioned - the delay time T _{u of} the controlled system can be regarded as constant, the reset time T _{I of} the speed controller can be permanently set for such a control behavior. If, on the other hand, good control behavior of a PI controller is required, then the optimization condition (13) applies for a permissible 20% overshoot with the shortest oscillation period:

If such a control behavior is desired, the optimized readjustment time T of the speed controller 13 from Eq. (12) can be determined continuously.

FIG. 6 shows a two-armed roller carrier 3 with direct drive in the gluing position, comparable to the illustration in FIG. 3. The running roller 2c is driven or braked directly by an electrical machine 63. The speed of the machine 63 and thus the speed of the running roller 2c is detected by a tachometer generator 64. The machine 63 is fed by a converter 65, which is designed as a four-quadrant actuator. The speed of the machine 63 is regulated by a speed controller 69, to which a current controller 67 is subordinate. In order to achieve a constant web tension, a position control with a dancer roller 9 for obtaining an actual position value, an adjusting device 11 for setting a desired position value, a comparator 10 for forming the position difference from the desired position value and actual position value and a position controller 8 are provided. The output voltage of the position controller 8 forms the setpoint for the speed controller 69, the actual value of which is supplied by the tachometer generator 64. The controller gain and the reset time of the speed controller 69 are set by a computing device 70, which will be explained later. The output signal of the speed controller 69 is the target value for the lower-level current controller 67, which is compared in a comparator 68 with the actual current value. The output voltage of the subordinate current regulator 67 controls the ignition angle of the ignition pulses of a headset 66.

The new roller 1 is assigned a direct drive of the same design. Its structure is described together with its function in accelerating the new roller 1 to the synchronous speed n _s . The electric machine 71 for driving the new roller is fed by a converter 73, which is also designed as a four-quadrant actuator. A speed controller 77 with a subordinate current controller 75 is assigned to the converter 73. During the acceleration process of the new roller 1, the ramp function generator 37 is again active, which increases the setpoint for the speed controller 77 according to a predetermined ramp function until the synchronous speed is reached. The output element of the ramp generator 37 is compared in a comparator 78 with the actual speed value tapped by a tachometer generator 72. The speed difference controls the speed controller 77. The output voltage of the speed controller 77 forms the target value for the subordinate current controller 75 and is compared with the actual current value in a comparator 76.

The control difference controls the current controller 75. The output voltage of the current regulator 75 is the control voltage for the control set 74 for generating the ignition pulses for the converter 73.

In such a roller carrier with direct drive, a roll change is carried out in a manner analogous to that in a roller carrier with belt drive. However, since both rollers 1, 2 are equipped with a direct drive 71, 63, no induction brakes are required and the process of changing a roller is somewhat easier. First, in the normal unwind position analogous to FIG. 1, the web runs off the old roll. The web tension is controlled via the direct drive 63 in accordance with the position controller 8, the speed controller 69 and the subordinate current controller 67. The control parameters of the speed controller 69 are continuously determined by the computing device 70. Immediately before the gluing process, the roll carrier swivels into the gluing position shown in FIG. 6. The influencing of the running roller 2c by the direct drive 63 remains in engagement. At the same time, the new roller 1 is accelerated to the synchronous speed in the manner described. In this case, those data are determined which are necessary for calculating the initial value of the moment of inertia of the new roller 1 and the initial value of its radius. Immediately before the adhesive command, the specification of optimized controller parameters by the computing device 70 to the speed controller 69 is ended. The computing device 70 takes over the data determined when the new roll starts up and calculates the optimized control parameters for the speed control of the new roll 1 following the gluing process using the initial value of the moment of inertia of the new roll 1 and the initial value of its radius Ramp generator 37 is switched off and instead the output signal of the position controller 8 is switched to the comparator 78 of the speed controller 77. At the same time, the starting values of the optimized controller parameters are input to the speed controller 77 by the computing device 70. The computing device 70 then continuously determines the optimized controller parameters from the decrease in the radius of the roll. The direct drive 63 is switched off, the residual roll is removed and a new roll is inserted. The direct drive 63 is stopped until the next gluing process.

Eq. (1) to (3) for controller optimization in the same way:

die wiederum zu Gl. (5.1) umgeformt werden kann:

Eq. Also applies to the ramp-up time t _s for a largely linear ramp-up. (5):

which in turn go to Eq. (5.1) can be reshaped:

For a roller driven by a direct drive (index d), however, instead of Eq. (6g) the Eq. (14d):

For the initial value J _{WO of} the moment of inertia of the roll, the GI. (5.1) into Eq. (14d) can be used. You then get GI. (14.1d):

The initial value of the roll's moment of inertia can thus be calculated according to Eq. (14.1 d) calculate if you know the synchronous speed n _s , the ramp-up time t _s until the synchronous speed is reached, the drive torque M _{k of} the direct drive or the armature current proportional to it, and the moment of inertia J _{M of} the direct drive. These variables are determined in the same way as already described.

For the initial value T _so the time constant of the controlled system, Eq. (7)

From this follows the initial value V _{RO of} the optimized controller gain according to Eq. (2.3):

Eq. Applies again to the instantaneous value of the time constant T _{s of} the controlled system. (8th):

For the instantaneous value J of the total moment of inertia related to the drive, Eq. (14d) in the general form (14.2d):

Mit Gl. (9)

nimmt Gl. (15d) die Form (15.1 d) an:

If the relationship (8) is solved again after T _S and Eq. (14.2d), we get Eq. (15d)

With Eq. (9)

takes Eq. (15d) the form (15.1 d) to:

und einen für einen Direktantrieb spezifischen Faktor k_d nach Gl. (16d) ein :

so nimmt die Gl. (15.1) die Form (15.2) an:

If one again leads the winding-specific summand A according to Eq. (10)

and a factor k _d specific to a direct drive according to Eq. (16d) a:

so Eq. (15.1) the form (15.2) to:

Eq. Applies to the optimized controller gain V _{Rd of} a speed controller for a roller with direct drive. (25d)

FIG. 1 shows an exemplary embodiment of a circuit arrangement 100 for determining the initial value J _{wo of} the role in a direct drive. The circuit arrangement 100 contains an integrator 96, which is connected to a potentiometer 93 via a switch 94 at the start of the startup of the new roller 1. The switch 94 operated by a command stage 103 is opened again when the roller 1 has reached the synchronous speed n _s . The integrator 96 thus integrates a constant input voltage until the synchronous speed is reached. The output voltage of the integrator 96 is a measure of the ramp-up time t _s .

The integrator 96 is followed by a division element 97, the dividend input of which is connected to the output of the integrator 96 and the divisor input of which is connected to the tachometer generator 72, which is assigned to the direct drive 71 for the new roller 1 in the illustration in FIG. 6. The next time the role is changed, the divider input of the division element 97 is connected to the other tachometer generator 64. The output of the division element 97 is connected to the one input of a multiplier 98, the second input of which is connected to the current measuring transducer 79 for detecting the armature current of the direct drive 71 of the new roller 1. During the next role change, this input of the multiplier 98 is connected to the current measuring transducer 104 of the other direct drive. The armature current of the machine accelerating the new roller 1 is in turn a measure of the drive torque. In order to take the proportionality factors into account, the measuring voltage for the armature current is passed through a potentiometer 105. The output voltage of the multiplier 98 is compared in a comparator 99 with a voltage which is set to a value corresponding to the moment of inertia J _{M of} the direct drive, for example on a further potentiometer 102. The output voltage of the comparator 99 is a measure of the desired initial value J _wo the moment of inertia of the roller in a direct drive. It is fed to the computer 70 via a switch 101. The switch 101 is closed by the command stage 103 as soon as the synchronous speed has been reached and is opened again immediately after the initial value of the moment of inertia has been transferred to the computer 70.

FIG. 1 shows the interaction of a speed controller with adjustable controller gain with a computer and with the circuit arrangements for determining the initial value of the moment of inertia of the roller, the initial value of the roller radius and the current roller radius. The reference numerals relate to the use in a roller carrier with belt drive according to FIGS. 1 to 5. The reference numerals for use in a roller carrier with direct drive according to FIGS. 6, 7 are given in brackets. The speed controller 13 contains an operational amplifier, the feedback of which is connected to the series connection of a capacitor and an ohmic resistor. The inverting input of the operational amplifier is acted upon by the control difference via an input resistor and a multiplier 106. The reset time of the controller, which is the product of the resistance value of the input resistance in the 11th inverting input and the capacitance of the capacitor defined in the feedback, remains constant, since the time constant of the path does not change as a prerequisite. The controller gain is the quotient of the resistance value of the resistance in the feedback and the input resistance. This gain, which is predetermined by the controller circuitry, can be changed by a factor V, which is fed to the multiplier 106 at its second input.

The factor V is supplied by the computer 50 as a corresponding voltage. The computer 50 continuously calculates Eq. (2.4g) to determine the optimized controller gain. For this purpose, the computer 50 needs the initial value Jwo of the moment of inertia of the roller 1, which is input to it by the circuit arrangement 80 according to FIG. 5 at the end of the acceleration process of the new roller 1. The computer 50 also requires the initial value Rwo and the current value R _{w of} the radius. These values are supplied to him in the manner described for FIG. 4.

In the case of a roller carrier with direct drive, the optimized controller gain is continuously processed by a computer 70 according to Eq. (2.5d) determined. The initial value Jwo of the moment of inertia of the roller 1 required for this is entered by the circuit arrangement 100 according to FIG. 7 at the end of the acceleration of the new roller 1. The instantaneous radius R _w is determined in a known manner, for example as shown in FIG. 4. In this case, the initial value of the radius is not required.

In addition to the possibility of changing the effective controller gain shown in FIG. 8, other ways known from control technology are also possible.

In the event that the reset time of the controller is also to be optimized, a capacitor with variable capacitance can be switched on in the feedback of the speed controller. For example, it is possible to use a motor-driven variable capacitor that is controlled by the computer.

Claims (5)

1. A regulating arrangement for a roller carrier (3), wherein a web (B) with a predetermined web tension is wound off a rotatably mounted roller (1), the roller being assigned an electromotive driving or braking device (5,17) having a speed regulator (13; 69, 77) associated with a computer (50; 70) which continuously derives optimised regulating parameters for the speed regulator (13; 69, 77) from the path parameters, characterised in that the computer (50; 70) ascertains the optimised regulator amplification and/or the optimised adjusting time of the speed regulator (13; 69, 77) from an initial value (J_wo) of its moment of inertia (Jw) determined during run-up operation of a new roller (1), and from the instantaneous radius of this roller (1) during winding off.

2. A regulating arrangement as claimed in Claim 1, for a roller carrier (3) having a belt drive (4) which is assigned an electric machine (5), characterised by a circuit arrangement (80) which determines the initial value (J_wo) of the moment of inertia (J_w) of the roller (1) from the measured values for the synchronous speed (n_s), for the time (t_s) until the synchronous speed has been reached, for the driving moment of the electric machine (5) and for the initial value (R_wo) of the radius (R_w) of the roller (1) and both from predetermined values for the moment of inertia (J_m) of the electric machine (5) and from the radius (r) of the driving rollers of the belt drive (4).

3. A regulating arrangement as claimed in Claim 2, characterised by a circuit arrangement (80) having the following features:

a) an integrator (81) for determining a voltage proportional to the run-up time (t_s), which integrator is connected to a constant input voltage (potentiometer 83) during the acceleration of the new roller (1) until the synchronous speed (n_s) has been reached,

b) a division element (84) whose inputs are supplied with the output voltage of the integrator (81) and of the voltage output of a tachogenerator (7) until the synchronous speed (n_s) of the new roller has been reached,

c) a multiplication element (85) whose inputs are supplied with the output voltage of the division element (84) and with a voltage (armature current l_a) proportional to the driving moment of the electric machine,

d) a comparison element (87) which forms the difference of the output voltage of the multiplying element (85) and of a voltage proportional to the moment of inertia (JM) of the electric machine (5), and

e) a further multiplying element (89) which serves to form a voltage a voltage proportional to the initial value (J_wo) of the moment of inertia of the roller (1), and whose inputs are supplied with the output voltage of the comparision element (87) and with a voltage which corresponds to the squared value of the ratio of the radius (r) of the driving rollers of the belt drive (4) and the initial value (R_wo) of the roller radius (R_w).

4. A regulating arrangement as claimed in Claim 1, for a roller carrier with an electric direct drive (63, 71), characterised by a circuit arrangement (100) which determines the initial value (J_wo) of the moment of inertia (J_w) of the roller (1) from measured values for the synchronous speed (n_s) for the time (t_s) until the synchronous speed (n_s) has been reached, for the driving moment of the direct drive (63, 71 ) and from a predetermined value for the moment of inertia (J_M) of the direct drive (63,71).

5. A regulating arrangement as claimed in Claim 4, characterised by a circuit arrangement (100) having the following features:

a) an integrator (96) which serves to form a voltage proportional to the run-up time (t_s) and which is connected to a constant input voltage (potentiometer 93) during the acceleration of the new roller (1) until the synchronous speed (n_s) has been reached,

b) a division element (97) whose inputs are supplied with the input voltage of the integrator (96) and with the tacho-voltage of the tachogenerator (72 and 64) in order to determine the synchronous speed (n_s) of the new roller (1),

c) a multiplying element (98) whose inputs are supplied with the output voltage of the division element (97) and with a voltage (anchor current l_a) proportional to the driving moment of the electric direct drive (63,71), and

d) a comparison element (99) for the formation of a voltage, which is proportional to the initial value (J_wo) of the moment of inertia (J_w) of the roller (1), from the difference of the output voltage of the multiplying element (98) and a voltage which is proportional to the moment of inertia (J_M) of the direct drive (63, 71).

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