FI118741B - Method of damping roll oscillation and apparatus for damping roll oscillation - Google Patents

Description

118741

Method for attenuating track vibration and attenuator for track vibration

The invention relates to a method for damping roll vibration. The invention further relates to a roll vibration damper and a fiber web machine or apparatus having a roll vibration damper.

s It is important for the operation of the rolls used in fiber web machines, such as paper machines and paper finishing machines, that the vibrations therein are sufficiently low. What is low enough depends on the intended use and position of the roll in question. The nip-forming rolls pressed against each other and the individually rotating rolls behave slightly differently from the point of view of the web being produced.

When oscillating, the nip forming rolls cause the web passing through the nip to produce a periodic pattern corresponding to the oscillation of the roll, which may be expressed as a corresponding variation in thickness, gloss, smoothness, density or the like - i.e., as desired and detrimental to web quality. The oscillation excitation usually corresponds to a multiple of the rotation frequency of either roll. This; v <oscillation is time-dependent, especially when the other roll of the nip is soft-surface, since the polymer used as the surface of the roll undergoes a deformation in travel time, · · ·: *, which does not recover during rotation, but j · * 20 again acts as a new stimulus and amplifies the vibration that begins. This phenomenon, known as barring, for example, can be reduced by appropriately varying driving conditions or driving parameters such as running speed, nip load, or torque distribution of the rollers. However, the goal of paper machines and paper finishing machines is to produce the most standardized grade as desired; 25 such that variation of the running parameters is sufficient to keep the vibration • · ·. ·· *. too low causes additional adjustment needs compared to a situation where ./* the oscillation would be controlled by other means. On-line -: "Especially on machines, changing the driving speed fast enough is usually not possible due to, among other things, the numerous adjustments and their slowness. Product:. ·. 30 ways are not kept constant during the change, but the end result. '· * ·· ! is of an unusual quality.

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A single oscillating roll, in turn, causes a periodic variation mainly corresponding to the tension of the web, in particular impairing the runnability of the machine. Vibrations also have a negative effect on the durability of structures 35, because vibration causes a constant fatigue load on the structures.

1 1 8741 2 A variety of methods and techniques have been proposed for solving the vibration problem in fiber web machines. Passive mass suppressors have been in use for decades.

Patent FI 101320B (corresponding EP Patent Publication EP 5 1015695B1) discloses a method and apparatus for damping roll vibration.

In the present invention, in a paper machine or paper finishing device, vibration is damped by a mass and spring forming a dynamic dampener by measuring the oscillation frequencies of the oscillating object with one or more oscillation sensors, in turn, changes the spring constant or mass of the dynamic attenuator to bring the dynamic frequency of the attenuator to the same as the problematic excitation frequency.

EP 1333123A1 discloses a vibration dampener for a roll of a web-processing device. This is accomplished by means of an active actuator such that a bending moment is applied to the shaft of the roll in phase displacement with respect to the oscillation, practically in the opposite phase. As actuator, • the publication discloses electric, electromagnetic, magnetostrictive,. 20 piezo-electric, hydraulic or pneumatic actuators.

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DE 19605416 B4 discloses a method of oscillation damping, wherein the primary system to be damped and a linear active oscillator, the linear active oscillator comprises: the vibration dampener is supplemented with additional components which: in the lateral system provide force and in the rotator system the moment between the body of the primary system to be damped and the passive vibration damper: ··· ·. ···. c) this force or moment is obtained by or derived from the absolute or relative position of the two bodies or by their relation to each other and by one selectable linear filter and transfer function; 35 d) the difference signal is obtained from the absolute or relative relationship of the bodies to each other; is applied as an input signal to the linear filter 3 118741, and a force or torque is obtained as an output signal.

In a plurality of applications of the present invention, the device assembly may be referred to as a roll vibration dampener or / and only as a damping component when referring to a component or other feature having at least one feature representing a damping factor cXX (XX index may vary numerically).

It is a further object of the invention to improve these known methods of vibration damping and to provide an effective and as widely available roll vibration dampener as possible. For example, the goal is to prevent and reduce the quality of the fiber web produced by barring without having to change the actual fiber web production parameters to prevent or eliminate barring. One object is to provide a method for effectively damping oscillation over a sufficiently wide frequency band without limiting itself to the structure's characteristic frequency environment. It is also an object to be able to adjust the specific frequency and the f * · ': damping of the roll vibration damping separately and, if necessary, perform this damping of the damping frequency. hair change and tuning while the fiber web machine is in use. One of the goals of the * J \ 20 is also to provide a separate device for vibrating problems. ·· '·, with quick connection, commissioning and tuning, **:' particularly accurate and suitably simple.

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According to a first aspect of the invention there is provided a method according to claim 1 for damping roll vibration. In accordance with another aspect of the invention, 25 is provided a roll vibration dampener for a fiber web machine. In accordance with a third aspect of the invention, a fiber web machine according to claim 22 is made.

··· • · • · · * ·. Preferably, the oscillator is adapted to oscillate at a desired frequency to be attenuated by the primary system, such as a barring frequency, such that the oscillation is controlled by the control circuits of the delayed resonator to dampen the fiber optic machine. In this case, the vibration of the roll can be significantly damped in the primary system of the fiber web machine. In this case, the reduction of roll vibration may advantageously be automatic or self-adjusting, and manual manual adjustment may not be necessary. In addition, a relatively accurate reduction of roll vibration is possible, i.e. the frequency of the counter-oscillator accurately compensates for the harmful vibration of the actual primary-oscillator.

The invention makes it possible to adjust the specific frequency and s attenuation of the mass suppressor simultaneously and independently of one another. This avoids the instability and sensitivity problems associated with existing systems. Furthermore, the invention makes it possible to use a power generating actuator without changing the dynamics and stiffness of the damper. The invention also eliminates the effect of nonlinearities of the force member and other e.g. time dependencies on the operation of the suppressor.

That is, the power control circuit of the present invention can advantageously fade the dynamics of the force element out of the system, thus operating in the environment of the damping resonance frequency itself. That is, the delayed resonator control circuit in a fiber web machine, in many applications, for example, two nested cascade-switched delayed resonator control circuits, allows for more accurate and thus more effective vibration damping. The method according to the invention has the following: * · *: It is also possible to compensate for possible non-: · * in the force element. linearities.

^ · 20 Vibration damping occurs in fiber web machines in a very wide frequency range of about 5 to 1000 Hz. Within this range of assemblies, this range may be narrower, with typical frequency ranges being, for example, presses L ..: 50-150 Hz, adhesive press coaters 40-100 Hz, calendars 250-500 Hz, winders 15-35 Hz, etc. For such typical frequency:; · The 25 areas are affected by, among other things, the rotational speeds of the rollers and. their multiple multiples, the characteristic frequencies of the frame structures and other similar structural factors.

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In the following, the invention will be described in more detail in the accompanying figures. \ den.

Fig. 1 shows a delayed resonator in a fiber web machine according to a number of embodiments of the invention,

Figure 2 illustrates in more detail the delayed resonator of Figure 1 in a fiber web machine 5118741

Fig. 3 shows an example of damping roll vibration according to numerous embodiments of the invention,

Fig. 4 shows the control of a delayed resonator by the cascade control principle according to a number of further embodiments of the invention; 5 Fig. 5 shows the amplitude curves of the attenuator in the frequency domain at various parameter values according to the numerous embodiments of the invention;

Fig. 6 illustrates the effect of tuning parameters of a roll vibration dampener on a frequency response.

Figure 1 illustrates a delayed-state resonator in a fiber web machine according to a plurality of embodiments of the invention. Fig. 2 is an enlarged view of a delayed resonator in a fibrous web machine according to a plurality of embodiments of the invention. Fig. 2 (and also 1) is a damping system such as a roll or primary system 120 having a mass of m12. The primary system 120 is secured to the substrate 100, or other structure, by a force Foist 123 whose coupling / other structure to the primary system 120 may be simplified comprising a spring 121 of spring constant k12 and a damping factor 122 of damping factor c12. The substrate 100 may be, for example, a frame structure, a second roll, a nip between rollers through which a fibrous web or similar structure is driven. The primary system 120 is coupled to: * 20 to a pulverizer 110 having a mass of m11. This coupling includes a spring 111, · · ·: ·: / · with a spring constant of k11, and a damper 112 with a damping factor of ^ .v c11. The coupling also includes an actuator 113, which may be electric, electromagnetic, piezoelectric, magnetostrictive, hydraulic, pneumatic or the like. The actuator is coupled between the vibrator 25 110 and the primary system 120. The control circuit also includes a controller 140 having a delay 141, gain 142. The controller 140 receives its incoming control signal: from sensor 115 such as a speed sensor or so-called. v. ** ··. dysanturilta. The control voltage output from the controller 140 passes through the amplifier 116 to the actuator 113.

«· 30 Figure 3 shows a schematic diagram showing an example of a weather. ·, In accordance with numerous further applications of the invention. In the figure, there is a weighted system, such as a roller, or primary system 220, having a mass of m22. The primary system 220 is secured to the substrate 200, or other structure, by a force F ^ t 223 whose coupling / other structure to the primary system 220 can be simplified comprising a spring 221 of spring constant k22 and a damping factor 222 of damping coefficient c22. The Pri determination system 220 is coupled to a vibrator 210 having a mass m21. This coupling includes a spring 211 having a spring constant k21 and a damper 5 212 having a damping factor c21. The coupling also includes an actuator 213 which may be electrical, electromagnetic, piezoelectric, magnetostrictive, hydraulic, pneumatic or the like. The actuator is coupled to the oscillator 210 such that a force sensor 214 is disposed between the actuator and the oscillator 210. The control circuit also includes a controller 240 having a delay 241 e.g. resistance, gain 242, a PID controller 243 and an operator 244. The controller 240 receives its incoming control signals from the force sensor 214 and the speed sensor 215, the output control voltage being supplied to the actuator 213.

In numerous embodiments of the invention, control circuit 140, 141, 142, is 166,133,155, 240, 241,242, 243,244,213,214,215,216 are realized to be cascaded. Suitably, a second control circuit can be inserted inside the first control circuit, so that two nested control circuits are used for control on the principle of a delayed resonator.

i1 · • · · •::. ·. Figure 4 thus illustrates the control of the delayed resonator by the cascade control principle! 1. '·, 1 20 according to a number of further embodiments of the invention, wherein the outer is the speed control circuit 301 and the inner power control circuit 302. also a method of control which advantageously avoids problems with the power generating actuator. The velocity is measured by a velocity sensor 215, which forms a velocity control circuit 301, i.e., an outer control circuit, with the control circuit 240 *. In addition to the speed measurement 215 in the mass 210, a force measurement 214 is added between the mass and the power generating actuator Fv. By means of this force measurement, another internal control circuit 302, i.e. the force control circuit, is implemented. In this case, the delayed and amplified speed signal is not directly supplied to the power generating actuator Fv, but is supplied as a reference to the inner power control circuit 302. Such two nested control circuits 301,302 are referred to herein as cascade control. It has the following benefits: • Faults can be eliminated in the inner control circuit 302 so that they do not interfere with the outer control circuit 301.

Non-linearities, time dependencies, etc. can be offset by the inner control circuit 302 so that they are not visible to the outer control circuit 301.

7 118741 • The stiffness and dynamics of the actuator are not visible in the operation of the damper.

The loss of actuator stiffness is based on the fact that, for example, when the gain of the outer circuit 301 is set to zero, the power reference of the inner power control circuit 302 becomes zero. In this case, the inner control circuit 302 maintains a zero force between the mass and the actuator, whereby the damper acts as if there were no actuator.

In numerous further applications of the invention (e.g., the Two Degree of Freedom method, TDF method), the delay and gain of a delayed resonator can be calculated so that both the specific frequency of the attenuator and its attenuation can be individually adjusted.

In the numerous embodiments of the invention, the formulas used to calculate the delay and gain of a delayed resonator can be derived by making the following position s = j <Dc ·· · c • · · on a characteristic polynomial CR (s) = mns2 + £? ; and solving the delay and confirmation of the equations below.

Thus, the delay and gain values obtained place the poles of the system on the imaginary acellar.

• · • · ···. Now instead of making an investment • · «* * · ** ·: ** ·. 5 = If> c

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let's make s = a + jb 4 • 4 j Now the real part of the characteristic polynomial is • · ^ e {CR {a + jb)} = mna2 - mnb2 + Cua + kn - gce'r'a cos (rcb) a -gce ~ T'absin (Tcb) 20 and imaginary part

Zm {CR (a + jb)} = 2mnab + cnb + gce ~ T'a sin (rcb) a -gce Ic "bcos (Tcb) 8 118741

The gain and delay calculations can now be derived from the new formulas __ -zXm (b (mnb2 ~ ku + mua2) / (cnb2 + mna3 + cna2 + battery + amnb2)) + ηπ

τ · ~ I

, n = 0,1,2, ...

and - (mna2 + mnb2 -cua-ku) etc ° (co $, (rcb) a + b sin (rci))) where α = -ωεζ and b = o) cy] ϊ ^ ζ2, ζ = damping factor, coc = characteristic frequency, mu 5 = mass of the damping device, Cu = damping constant of the damping device, kn - constant force of the damping device, tc = adjustable delay of the damping device and gc = gain of the dimming device.

That is, it is possible to control both the characteristic frequency and the attenuation of the system independently of each other. An additional example below illustrates this further.

ίο Figure 5 shows the results for a system where the passive attenuator v (no adjustment) parameter values are: · · • ml - 20 kg and specific frequency / = 120 Hz »·· im • · · · · ··· * * • • 15 Relative attenuation is 5% so «_ • · · I 1 * ::: * c. = 2mXj ^ - = l50SNs / m:: ym, ··« * 1 t ·: m ”In Fig. 5, the amplitude curves of the attenuator in the frequency domain with different parameter values (pas- '· ♦♦ * wing attenuator (no adjustment) - 401, adjustable attenuator 125 Hz resonance frequency and 1% attenuation - 402, adjusted attenuator 125 Hz resonance frequency. * 20 and 5% attenuation - 403, adjustable attenuator 125 Hz resonance frequency and 10% attenuation - 404). Curve 401 shows the amplitude of the attenuator as a function of frequency without adjustment. Naturally, the maximum amplitude is obtained at a specific frequency of 120 Hz. Now, using the formulas shown in numerous embodiments of the invention, the attenuator is tuned to 125 Hz with three different attenuations. The curves g 118741 402,403 and 404 show these responses obtained with different attenuation. It will now be seen that even the attenuation can be adjusted without affecting the characteristic frequency.

Figures 6A-6D show the frequency response function of a damped structure from a primary system such as a roll bearing housing to a nip. The horizontal axis is the frequency and the vertical axis is the displacement / force. The resonance without the attenuator is represented by the dashed line, and the solid line represents the resonance with the attenuator.

Figures 6A and 6B show the effect of pulp. Fig. 6A shows a large mass of the damper, the peaks spaced apart, and Fig. 6B has a small mass, whereby the peaks are close together. It is desired to tune the attenuator so that the barring frequency is in the valley between the peaks with the lowest response. Even a small deviation in tuning increases the response much.

Figures 6C and 6D show the effect of damping. In Figure 6C, the attenuation of the damper is large, with the valley between the two peaks being 15 flat and the bottom of the valley not very deep. In Figure 6D, the damping is small and the bottom of the valley is deep.

* «T: V Due to the versatility and ease of placement of the roll vibration dampener i .::, it is advantageous to minimize the weight of the dampener.

As a result, the tuning accuracy must be as good as possible and the damping as small as possible in order to obtain the deepest bottom, i.e., the roll vibration dampener, of the ♦ ··: hollow in Figures 6A-6D. work as efficiently as possible.

··· • »* • * ··· • m · • • • •» »• • • * • • • • • • • • • • • • • • • • • • • • • • • • • • · * · • · • * ·· * 10 118741

Reference numerals used in the drawings: 100 chassis 110 vibrator (m11) 111 spring (k11) s 112 damper (c11) 113 actuator 114 force sensor 115 speed sensor 116 amplifier ίο 120 primary system 121 spring (k12) 122 damper (c12) 123 force (Fdist) 140 adjusters is 141 delay 142 gain 200 feet 210 vibrator (m21) Γν 211 spring (k21): 20 212 damper (c21) • · · · '':: *: 213 actuator • · ·. ** ·. 214 force sensor • * 215 speed sensor * · · "I 216 amplifier • * ***** 25 220 primary system, 221 spring (k22) 222 damper (c22) 223 force 240 controller •. ···. 30 241 delay • · 242 gain • m: · 243 second control ··· 244 operator 35

Claims (23)

118741 A method for damping roll vibration in a fiber web machine, wherein the one or more rolls to be damped forms a primary system (120, 220) that can oscillate with a substrate (100, 200) such as run-5 or another roll and a primary system (120, 220). ) and the support (100, 200) can be reduced to a force (123, 223), a spring constant (121, 221) and a damping (122, 222) to which a vibrator (110, 210) is attached to the primary system (120, 220). having a mass less than the mass of the primary system whose vibrator (110, 210) attachment can be reduced to include a spring (111, 211), a damper (112, 212) and an actuator (113, 213), and whose vibrator (110, 210) acceleration, velocity and / or position are monitored by a sensor (115, 215) which provides an input signal to the controller (140, 240), from which the output signal from the controller controls the vibrator actuator (113, 213), characterized in that: a vibrator (110, 15 210) oscillates the primary system (120, 220) for filling with the desired HÖ rähtelytaajuutta such as a barring frequency of the corresponding frequency so that the vibration is controlled with delayed resonator principle for damping roll vibration, the fiber web machine. A method according to claim 1, characterized in that the oscillations: - 20 are controlled by the cascade-delayed resonator principle. »· · I« »··· Method according to claim 1 or 2, characterized in that the vibration is controlled by the first control circuit (301) and its nested. a second control circuit (302) according to the delayed resonator principle. • · · A method according to claim 3, characterized in that the first control circuit controls the vibration speed and the second control circuit controls the vibration force. • ·: -v A method according to claim 1, characterized in that the vibration delay is controlled in a controlled manner by the following formula: ψ: ·: \ _ - & \ an (b (mub2-ku + mua2) / (cub2 + mua3 + cua2 + α! ΐη + αιηη02)) + ηπ ..... 30 re = _. The method of claim 1, characterized in that the gain of the oscillation is controlled in a controlled manner by the following formula: 118741 _- {mna2 + mub2 -cna ~ ku) eT (cos (rcb) a + bsm (Tcb)) A method according to claim 1, characterized in that the adjustment of the oscillation comprises adjusting the characteristic frequency or damping of the oscillation. A method according to claim 1, characterized in that the vibrator vibrates passively or under the control of the actuator (113, 213). Method according to claim 1, characterized in that between the actuator and the oscillator there is a force sensor (214), from which the signal is applied to an operator (244) which processes the signal received from the force sensor and the output signal to one of the other controllers (243). an input signal from which the signal from the second controller (243) controls the actuator. Method according to claim 9, characterized in that, based on the information received from the vibrator sensor (215) and / or the force sensor (214), the vibration frequency and phase of the primary system (120, 220) are calculated to determine the required delay (241) and gain. (242). A method according to claim 1, characterized in that the damped oscillation frequency is in the range of 5 to 1000 Hz. • · »* ·· t:.: 'Ί 12. A roller vibration damper for a fiber web machine, which comprises: ··· * · · 20 primary systems (120, • · * ··· 220) of one or more rolls, which can oscillate with respect to the substrate (100, 200), a vibrator (110, 210) adapted to be attached to the primary beam; ***. 25, characterized by the fact that the damper includes: · · · •: means (113, 213, 214, 216, 243, 244 ) to adjust the oscillator * "* of the oscillator (110, 210) on the principle of a delayed resonator such that the oscillator is adapted to oscillate at the desired attenuation frequency of the primary system, such as barring, to attenuate the oscillation of the te-30. 118741 An attenuator according to claim 12, characterized in that said means include means for cascading the vibrator in accordance with the delayed resonator principle. Roll vibration damper according to Claim 12, characterized in that the means comprise a first control circuit and a nested second control circuit for adjusting it according to the delayed resonator principle. An attenuator according to claim 14, characterized in that the first control circuit is adapted to control the vibration rate and the second control circuit is adapted to control the vibration force. ίο An attenuator according to claim 12, characterized in that the oscillation delay is adapted to be controlled in a controlled manner by the following formula: - atan (6 (mu & 2-ku + mua2) / (cub2 + mua3 + cna2 + akn + amub2)) + ηπ Tc _ _ An attenuator according to claim 1, characterized in that the oscillation gain is adapted to be controlled in a controlled manner by the following formula: 15 _- (mua2 + mub2 ~ Cua ~ ku): **]: Sc eT'a (cos (Tcb) a + bsin ( Tcb)) • · • · · • · 7X Roll vibration damper according to Claim 12, characterized in that the substrate (100, 200) includes a frame or other roll, and the connection between the primary frame (120, 220) and the substrate (100, 200) can be performed. reduced to force (123, 223), spring constant (121, 221) and damping (122, 222), 20 and whose attachment of the vibrator (110, 210) may be reduced to include a spring (111, 211), a damper (112, 212) and an actuator (113, 213), and whose acceleration, velocity and / or position of the oscillator (110, 210) is monitored by a sensor (115, 215) which provides an input signal to the regulator (140, 240). ) ·. the output signal from the actuator controls the vibrator actuator (113, 25 2 1 3). • · «♦ •»:! ·. Roll vibration damper according to claim 12 or 18, characterized in that a power sensor (214) is provided between the actuator and the vibrator, from which the signal is applied to an operator (244) which processes the signal from the power sensor and the output signal to another controller (243). ) 118741 as an input signal from which the signal from the other controllers (243) controls the actuator. Roll vibration damper according to claim 19, characterized in that, based on the information received from the vibrator sensor (215) and / or the force sensor (214), the vibration frequency and phase of the primary system (120, 220) are calculated to determine the required delay (241). ) and confirmation (242). Roll vibration damping device according to claim 12, characterized in that said means are adapted to control the vibration frequency to be damped from 5 to 1000 Hz. A fiber web machine comprising a roll vibration damper, the fiber web machine comprising: a primary system (120, 220) formed by one or more rolls, which can oscillate with respect to the substrate (100, 200), and 15 oscillators (110, 210) arranged for attachment to a primary system for damping oscillation, and having a mass of the oscillator smaller than the mass of the primary system, characterized by the fact that the damping device includes a control circuit according to the delayed resonator principle (113, 213, ** "20 214, 216, 240, 241, 242, 243, 244) to adjust the vibration of the oscillator: 'So that the oscillator can vibrate at a frequency corresponding to the desired frequency of the primary system, such as the barring frequency, to suppress the oscillation of the oscillator. • 1 • · • · · *. ···. A fiber web machine according to claim 22, characterized in that • · | 1 | Said control circuit includes two nested control circuits according to the delayed resonator principle. ·· «· • · · 1 · * 1 • · 9 • · • M · · 118741