CN104141723B - The compound dynamic vibration absorber that a kind of natural frequency is adjustable and controlling method thereof - Google Patents

Abstract

The invention provides the adjustable compound dynamic vibration absorber of a kind of natural frequency and controlling method thereof, comprise signal gathering unit, control unit, performance element, wherein performance element can be in harmonious proportion the adjustable two-part of quality by rigidity and forms.Rigidity adjustable elements comprises and connects U-shaped pedestal, and with field coil and pretension bolt on U-shaped pedestal, absorber block is in the middle of two magnetic rheology elastic bodies, by the effect of pretension bolt pretension, is fixed in the middle of two clamping plate.Described liquid tank, liquor pump are connected by flexible pipe with liquid cavity of resorption.The design's structure is simple, good damping result, effective vibration damping Bandwidth, stable performance, the control response time is short, have very high use value, the present invention has widened vibration damping frequency band further on existing self-adapting type bump leveller basis, solves the problem that traditional type dynamic vibration absorber effective vibration damping frequency band is too narrow; Overcome the defect that active power bump leveller too relies on outside energy.

Description

The compound dynamic vibration absorber that a kind of natural frequency is adjustable and controlling method thereof

Technical field

The invention belongs to vibration control field, be specifically related to the adjustable compound dynamic vibration absorber of a kind of natural frequency and controlling method thereof.

Background technique

Because structure is simple, the good and steady performance of Economy, dynamic vibration absorber is widely applied in vibration control fields such as mechanical system, engineering structure, bridge and buildings.As shown in Figure 1, compound dynamic vibration absorber quality, rigidity are respectively m to dynamic vibration absorber working principle _`1, k ₁, absorber mass, rigidity are respectively m ₂, k ₂, the displacement of compound dynamic vibration absorber under harmonic excitation power fsin (ω t) effect is x ₁, bump leveller displacement is x ₂, from vibration mechanics theory, its motion equation is such as formula 1:

$\left\{\begin{array}{c}{m}_1{\stackrel{\·\·}{x}}_1+k_1{x}_1+k_2\left(x_1-x_2\right)=f\sin \left(\mathrm{\ω}t\right)\\ m_2{\stackrel{\·\·}{x}}_2+k_2\left(x_2-x_1\right)=0\end{array}\right.---\left(1\right)$

Solve and can obtain compound dynamic vibration absorber vibration amplitude and be:

$x_1=\frac{(k_2-m_2{\mathrm{\ω}}^2)f}{(k_1+k_2-m_1{\mathrm{\ω}}^2)(k_2-m_2)-{k_2}^2}---\left(2\right)$

From above formula, k ₂-m ₂ω ²when=0, namely time, compound dynamic vibration absorber amplitude is minimum is zero.Therefore, when bump leveller natural frequency equals extraneous excited frequency, bump leveller effectively can reduce the vibration of compound dynamic vibration absorber.But traditional power bump leveller structural parameter are immutable, natural frequency is unadjustable, and effective vibration damping frequency band is too narrow, and when extraneous excited frequency departs from bump leveller natural frequency, its damping property significantly reduces.Active power bump leveller can solve the narrow problem of vibration damping frequency band, effective vibration damping in broad frequency band.But active power bump leveller needs a large amount of outside energy, and cost is high, complex structure, and regulate not at that time, not only lose damping property, also may aggravate the vibration of compound dynamic vibration absorber.The domestic patent No. be 96107066.8 patent of invention be passive type bump leveller.Its vibration damping frequency band is too narrow, can only rely on and increase damping or absorber mass and adopt the method for multiple absorber block to widen absorbing frequency band, but theoretical proof, increases the damping property that damping can lower bump leveller, and frequency band is widened and not obvious; Gain in weight and make structure bulky, owing to being subject to spatial constraints etc., increase absorber block number is also unrealistic.The domestic patent No. be 94246820.1 utility model patent refer to a kind of bump leveller of combined type ACTIVE CONTROL.Principle adds active controlling force on the basis of passive type bump leveller, but bump leveller natural frequency is still non-adjustable, and it is far away that extraneous excited frequency departs from bump leveller natural frequency, required active controlling force is larger, so design heavy dependence outside energy, realizes cost high, poor practicability.

For widening bump leveller effective band, a lot of scholar's research according to dynamic excitation frequency adjustment structural parameter, thus can change the self-adapting type dynamic vibration absorber of self natural frequency in recent years.It not only has the advantages such as traditional type dynamic vibration absorber structure is simple, stable performance, good economy performance, can carry out effective vibration damping simultaneously, and rely on outside energy not too much, have very high research and use value in broad frequency band.Foreign scholar Abu-Akeel proposes a kind of self-adapting type bump leveller being changed rigidity by electromagnetic force.Williams and Rustighi utilizes marmem to devise the adjustable dynamic vibration absorber of rigidity as elastic element respectively, this alloy has different metallurgical structure when different temperatures, its Young's modulus (relevant to rigidity) also can change thereupon, and alloy temperature is by the Current Control passed through.The domestic patent No. be 200510094882.3 patent of invention utilize magnetic rheology elastic body to devise a kind of frequency-shift type bump leveller, its working principle is that magnetic rheology elastic body is under the effect of variation magnetic field, Young's modulus changes, change the rigidity of magnetic rheology elastic body with this, realize the adjustment to bump leveller natural frequency.Above-mentioned self-adapting type bump leveller solves the too narrow problem of traditional type bump leveller vibration damping frequency band, and does not need a large amount of outside energy.But above design is all the adjustment being realized bump leveller natural frequency by the rigidity of modifier, but limits by material property, and its frequency band is widened limited, how widening the effective vibration damping frequency band of bump leveller is further study urgent problem now; And above design is when controlling to lose efficacy, and shows as passive type bump leveller, loses the performance of vibration damping on wideband.

Summary of the invention

For above-mentioned defect or deficiency, the compound dynamic vibration absorber that the object of the present invention is to provide a kind of natural frequency adjustable and controlling method thereof, can solve the problem that traditional type dynamic vibration absorber effective vibration damping frequency band is too narrow.

For reaching above object, technological scheme of the present invention is:

The compound dynamic vibration absorber that natural frequency is adjustable, comprising: actuator, signal gathering unit and control system;

Actuator comprises: be arranged at the rigidity adjustable elements on vibrating object, rigidity adjustable elements be provided with fixed mass unit, fixed mass unit is provided with fluid box, fluid box is connected with water supply installation; Wherein, rigidity adjustable elements comprises the U-shaped pedestal be arranged on vibrating object, U-shaped pedestal is provided with the field coil for generation of magnetic field, the opening of U-shaped pedestal is provided with a pair clamping plate by installing pretension bolt, absorber block is clamped with by magnetic rheology elastic body between clamping plate, form a closed magnetic conductive loop, fixed mass cellular installation is on absorber block;

Signal gathering unit comprises: be installed on flow transducer and charge amplifier that fixed mass unit is connected with water supply installation for acceleration transducer bump leveller being carried out to vibration signals collecting, the output terminal of acceleration transducer is connected with the input end of charge amplifier; Charge amplifier is connected with the input end of control system with the output terminal of flow transducer;

The output terminal of control system is connected with controllable electric power and water supply installation, and the output terminal of controllable electric power is connected with field coil.

Described water supply installation comprises: liquor pump, liquid tank and motor; Fluid box is connected with liquor pump by flexible pipe, and liquor pump is connected with liquid tank, and one end of motor is connected with liquor pump, and the other end of motor is connected with the output terminal of control system.

Described fluid box is divided into liquid cavity of resorption and air epicoele by piston, and piston is provided with spring, and the other end of spring is connected with the top of fluid box.

Described U-shaped pedestal, pretension bolt, clamping plate and absorber block are high permeability material.

A controlling method for the compound dynamic vibration absorber that natural frequency is adjustable, comprises the following steps:

1) extraneous excited frequency ω suffered by compound dynamic vibration absorber, is obtained;

2), set vibration damping frequency band as and by the vibration damping frequency band quartering, the end points of its quartering frequency band is designated as ω respectively ₁, ω ₂, ω ₃, ω ₄, ω ₅, wherein:

First frequency range is: [ω ₁, ω ₂], namely

Second frequency range is: [ω ₂, ω ₃], namely

3rd frequency range is: [ω ₃, ω ₄], namely

4th frequency range is: [ω ₄, ω ₅], namely

In formula, k _minfor compound dynamic vibration absorber minimum rigidity, namely do not add rigidity during electric current, k _maxfor compound dynamic vibration absorber maximum rigidity, namely add electric current maximum time rigidity, m is the quality of fixed mass unit, and Δ m is variable-quality in the first frequency range fluid box, Δ m _x1be variable-quality in the second frequency range fluid box, Δ m _x2it is variable-quality in the 3rd frequency range fluid box;

Further, make:

$\left\{\begin{array}{c}\sqrt{\frac{k_{max}}{m+\mathrm{\Δ}m}}=\sqrt{\frac{k_{min}}{m+{\mathrm{\Δm}}_{x1}}}\\ \sqrt{\frac{k_{max}}{m+{\mathrm{\Δm}}_{x1}}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\Δm}}_{x2}}}\\ \sqrt{\frac{k_{max}}{m+{\mathrm{\Δm}}_{x2}}}=\sqrt{\frac{k_{min}}{m}}\end{array}\right.---\left(3\right)$

?

$\left\{\begin{array}{c}\mathrm{\Δ}m=\frac{k_{max}^3\×m}{k_{min}^3}-m\\ {\mathrm{\Δm}}_{x1}=\frac{k_{max}^2\×m}{k_{min}^2}-m\\ {\mathrm{\Δm}}_{x2}=\frac{k_{\max }\×m}{k_{\min }}-m\end{array}\right.---\left(4\right)$

3), make:

$\left\{\begin{array}{c}{\mathrm{\ω}}_1=\sqrt{\frac{k_{\min }}{m_{\min }+\mathrm{\Δ}m}}\\ {\mathrm{\ω}}_2=\sqrt{\frac{k_{\max }}{m+\mathrm{\Δ}m}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\Δm}}_{x1}}}\\ {\mathrm{\ω}}_3=\sqrt{\frac{k_{\max }}{m+{\mathrm{\Δm}}_{x1}}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\Δm}}_{x2}}}\\ {\mathrm{\ω}}_4=\sqrt{\frac{k_{\max }}{m+{\mathrm{\Δm}}_{x2}}}=\sqrt{\frac{k_{\min }}{m}}\\ {\mathrm{\ω}}_5=\sqrt{\frac{k_{\max }}{m}}\end{array}\right.---\left(5\right);$

4), determine frequency band division relation after, in bump leveller vibration damping frequency band, variable-quality m in fluid box _xcontrol adopt following control strategy:

$m_x=\left\{\begin{array}{c}\mathrm{\&Delta;}m.....................\mathrm{..}{\mathrm{\&omega;}}_1\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_2\\ {\mathrm{\&Delta;m}}_{x1}..................{\mathrm{\&omega;}}_2\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_3\\ {\mathrm{\&Delta;m}}_{x2}..................{\mathrm{\&omega;}}_3\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_4\\ 0........................{\mathrm{\&omega;}}_4\&le;\mathrm{\&omega;}\&le;{\mathrm{\&omega;}}_5\end{array}\right.---\left(6\right)$

5), control system extraneous excited frequency ω suffered by obtained compound dynamic vibration absorber, and the control strategy corresponding to vibration damping frequency band, controls water supply installation and injects fluid box or export the water yield; And, control system obtains rigidity needed for bump leveller, the relation of rigidity and electric current needed for bump leveller, determine the required electric current applied, simultaneously according to the electric current of required applying, control signal is passed to controllable electric power, the electric current flowing to field coil is regulated after controllable electric power reception control signal, fine tuning is carried out to rigidity, by rigidity fine tuning, realizes the tracking of frequencies omega to external world.

Suffered by the compound dynamic vibration absorber of described acquisition, the figure process that occupies of extraneous excited frequency ω is:

Charge amplifier receives the acceleration signal transmitted by acceleration transducer, degree of will speed up signal changes charge signal into and sends control system to, control system obtains extraneous excited frequency ω suffered by compound dynamic vibration absorber through fft after receiving charge signal.

Compared with the prior art, beneficial effect of the present invention is:

1, the invention provides the compound dynamic vibration absorber that a kind of natural frequency is adjustable, this device is owing to arranging actuator, signal gathering unit and control system composition, according to signal gathering unit and control system, the natural frequency to bump leveller regulates in actuator, make the structure of bump leveller simple, controlling method easily realizes, and system reliability is high.

2, the present invention is by regulating two parameters of bump leveller rigidity and quality, and the basis of existing self-adapting type bump leveller has been widened effective vibration damping frequency band of bump leveller further.

3, vibration control fast response time of the present invention, design adopts rigidity, quality regulates simultaneously, can make bump leveller rapid adjustment natural frequency, significantly reduce the control response time.

4, effectiveness in vibration suppression of the present invention is obvious, in the basicly stable situation of compound dynamic vibration absorber vibration frequency, and can effectively to compound dynamic vibration absorber vibration damping

5, power consumption is few, and the design only need provide the electric current and motor pump liquid electric current that change magnetic field, significantly reduces the energy needed for ACTIVE CONTROL.

6, the invention provides the controlling method of the adjustable compound dynamic vibration absorber of a kind of natural frequency, by regulating two parameters of bump leveller rigidity and quality, make to regulate reliability high, design adopts double system independently to control, rigidity adjustable elements and quality adjustable elements separate, when a certain unit breaks down, can avoid the defect that bump leveller adjusting function is lost entirely, its performance is more stable.

Accompanying drawing explanation

Fig. 1 is traditional power bump leveller schematic diagram of device;

Fig. 2 is the adjustable compound dynamic vibration absorber structural representation of natural frequency of the present invention;

Fig. 3 is rigidity adjustable elements structural representation of the present invention;

Fig. 4 is rigidity adjustable elements magnetic field of the present invention circulation schematic diagram;

Fig. 5 is quality adjustable elements structural representation of the present invention;

Fig. 6 is controlled system time-domain diagram of the present invention;

Fig. 7 is that frequency of the present invention widens effect contrast figure;

Fig. 8 is the relation-matched curve figure of rigidity and electric current;

Fig. 9 is compound dynamic vibration absorber amplitude-versus-frequency curve figure under different electric current.

In figure, 1 is rigidity adjustable elements, and 2 is absorber block, and 3 is pretension bolt, 4 is U-shaped pedestal, and 5 is field coil, and 6 is magnetic rheology elastic body, and 7 is clamping plate, 8 is magnetic field line, and 9 is fixed mass unit, and 10 is fluid box, and 11 is acceleration transducer, 12 is flexible pipe, and 13 is flow transducer, and 14 is controllable electric power, and 15 is control system, 16 is charge amplifier, and 17 is motor, 18, liquor pump, and 19 is liquid tank, 20 is spring, and 21 is liquid cavity of resorption, and 22 is piston, and 23 is air epicoele.

Embodiment:

Below in conjunction with accompanying drawing, the present invention is described in detail.

As shown in Figure 2,3, 4, the invention provides the compound dynamic vibration absorber that a kind of natural frequency is adjustable, comprising: actuator, signal gathering unit and control system 15;

Actuator comprises: be arranged at the rigidity adjustable elements 1 on vibrating object, rigidity adjustable elements 1 be provided with fixed mass unit 9, fixed mass unit 9 is provided with fluid box 10, fluid box 10 is connected with water supply installation; Wherein, rigidity adjustable elements 1 comprises the U-shaped pedestal 4 be arranged on vibrating object, U-shaped pedestal 4 is provided with the field coil 5 for generation of magnetic field, the opening of U-shaped pedestal 4 is provided with a pair clamping plate 7 by installing pretension bolt 3, absorber block 2 is clamped with by magnetic rheology elastic body 6 between clamping plate 7, form a closed magnetic conductive loop, fixed mass unit 9 is installed on absorber block 2; Described water supply installation comprises: liquor pump 18, liquid tank 19 and motor 17; Fluid box 10 is connected with liquor pump 18 by flexible pipe 12, and liquor pump 18 is connected with liquid tank 19, and one end of motor 17 is connected with liquor pump 18, and the other end of motor 17 is connected with the output terminal of control system 15.

Signal gathering unit comprises: be installed on flow transducer 13 and charge amplifier 16 that fixed mass unit 9 is connected with water supply installation for the acceleration transducer 11 carrying out vibration signals collecting to bump leveller, the output terminal of acceleration transducer 11 is connected with the input end of charge amplifier 16; Charge amplifier 16 is connected with the input end of control system 15 with the output terminal of flow transducer 13;

The output terminal of control system 15 is connected with controllable electric power 14 and water supply installation, and the output terminal of controllable electric power 14 is connected with field coil 5.

As shown in Figure 5, described fluid box 10 is divided into liquid cavity of resorption 21 and air epicoele 23 by piston 22, piston 22 is provided with spring 20, and the other end of spring 20 is connected with the top of fluid box 10.

It should be noted that, in the present invention, U-shaped pedestal 4, pretension bolt 3, clamping plate 7 and absorber block 2 is high permeability material, and U-shaped pedestal 4, pretension bolt 3, clamping plate 7, magnetic rheology elastic body 6, absorber block 2 form a closed magnetic conductive loop, magnetic direction passes perpendicularly through magnetic rheology elastic body 6, and magnetic direction is as shown in magnetic field line 8.

The present invention utilizes magnetic rheology elastic body 6 as the elastic element of bump leveller, and absorber mass is divided into the quality of fluid box 10 in the quality of fixed mass unit 9 and mass-adjustable.The natural frequency of bump leveller is adjusted by the change of magnetic rheology elastic body 6 rigidity and the change of bump leveller effective mass.Acceleration transducer 11 is utilized to gather compound dynamic vibration absorber oscillating signal, control system 15 is sent to through charge amplifier 16, described control system 15 is computer, control system 15 pairs of signals carry out fft, draw extraneous excited frequency suffered by compound dynamic vibration absorber, send control signal according to this, the size of control controllable electric power 14 electric current changes the magnetic field residing for magnetic rheology elastic body 6, the electric current simultaneously changing supply motor 17 controls liquor pump 18 and pumps into or pump liquid, with liquid flow sensor 13 wherein and on flexible pipe 12, Real-time Feedback is carried out to fluid flow information.Through the above-mentioned adjustment to bump leveller rigidity and quality, change bump leveller natural frequency fast, to realize the tracking of excited frequency to external world, reach best vibration damping.

Present invention also offers the controlling method of the adjustable compound dynamic vibration absorber of a kind of natural frequency, comprise the following steps:

1) extraneous excited frequency ω suffered by compound dynamic vibration absorber, is obtained;

2), set vibration damping frequency band as and by the vibration damping frequency band quartering, the end points of its quartering frequency band is designated as ω respectively ₁, ω ₂, ω ₃, ω ₄, ω ₅, as shown in Figure 8, wherein:

First frequency range is: [ω ₁, ω ₂], namely

Second frequency range is: [ω ₂, ω ₃], namely

3rd frequency range is: [ω ₃, ω ₄], namely

4th frequency range is: [ω ₄, ω ₅], namely

In formula, k _minfor compound dynamic vibration absorber minimum rigidity, namely do not add rigidity during electric current, k _maxfor compound dynamic vibration absorber maximum rigidity, namely add electric current maximum time rigidity, m is the quality of fixed mass unit, and Δ m is variable-quality in the first frequency range fluid box, Δ m _x1be variable-quality in the second frequency range fluid box, Δ m _x2it is variable-quality in the 3rd frequency range fluid box;

Further, for ensureing that whole frequency range is continuous, order:

$\left\{\begin{array}{c}\sqrt{\frac{k_{max}}{m+\mathrm{\&Delta;}m}}=\sqrt{\frac{k_{min}}{m+{\mathrm{\&Delta;m}}_{x1}}}\\ \sqrt{\frac{k_{max}}{m+{\mathrm{\&Delta;m}}_{x1}}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x2}}}\\ \sqrt{\frac{k_{max}}{m+{\mathrm{\&Delta;m}}_{x2}}}=\sqrt{\frac{k_{min}}{m}}\end{array}\right.---\left(3\right)$

?

$\left\{\begin{array}{c}\mathrm{\&Delta;}m=\frac{k_{max}^3\&times;m}{k_{min}^3}-m\\ {\mathrm{\&Delta;m}}_{x1}=\frac{k_{max}^2\&times;m}{k_{min}^2}-m\\ {\mathrm{\&Delta;m}}_{x2}=\frac{k_{\max }\&times;m}{k_{\min }}-m\end{array}\right.---\left(4\right)$

3), in formula (4), Δ m can be determined by the relation of Δ m and bump leveller invariant mass m, and then determine Δ m successively _x1, Δ m _x2, so far ensure that bump leveller is continuous over the entire frequency band.Order:

$\left\{\begin{array}{c}{\mathrm{\&omega;}}_1=\sqrt{\frac{k_{\min }}{m_{\min }+\mathrm{\&Delta;}m}}\\ {\mathrm{\&omega;}}_2=\sqrt{\frac{k_{\max }}{m+\mathrm{\&Delta;}m}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x1}}}\\ {\mathrm{\&omega;}}_3=\sqrt{\frac{k_{\max }}{m+{\mathrm{\&Delta;m}}_{x1}}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x2}}}\\ {\mathrm{\&omega;}}_4=\sqrt{\frac{k_{\max }}{m+{\mathrm{\&Delta;m}}_{x2}}}=\sqrt{\frac{k_{\min }}{m}}\\ {\mathrm{\&omega;}}_5=\sqrt{\frac{k_{\max }}{m}}\end{array}\right.---\left(5\right);$

4), determine frequency band division relation after, in bump leveller vibration damping frequency band, variable-quality m in fluid box 10 _xcontrol adopt following control strategy:

$m_x=\left\{\begin{array}{c}\mathrm{\&Delta;}m.....................\mathrm{..}{\mathrm{\&omega;}}_1\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_2\\ {\mathrm{\&Delta;m}}_{x1}..................{\mathrm{\&omega;}}_2\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_3\\ {\mathrm{\&Delta;m}}_{x2}..................{\mathrm{\&omega;}}_3\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_4\\ 0........................{\mathrm{\&omega;}}_4\&le;\mathrm{\&omega;}\&le;{\mathrm{\&omega;}}_5\end{array}\right.---\left(6\right)$

5), control system 15 extraneous excited frequency ω suffered by obtained compound dynamic vibration absorber, and the control strategy corresponding to vibration damping frequency band, controls water supply installation and injects fluid box 10 or export the water yield; And, control system 15 obtains rigidity needed for bump leveller, the relation of rigidity and electric current needed for bump leveller, determines the required electric current applied, simultaneously according to the electric current of required applying, control signal is passed to controllable electric power 14, regulate the electric current flowing to field coil 5 after controllable electric power 14 reception control signal, fine tuning is carried out to rigidity, by rigidity fine tuning, realize the tracking of frequencies omega to external world, reach best vibration damping.The time-domain diagram of controlled system under the design's effect in Fig. 6.When in bump leveller working procedure, when natural frequency is not equal to extraneous excited frequency, by frequency range judge carry out quality adjustment and rigidity fine tuning after, make bump leveller to external world excited frequency follow the trail of, finally reach optimal control.

Described step 5) in needed for bump leveller the pass of K rigidity and electric current I be:

$K=\left\{\begin{array}{c}1060.1I^4-4538.8I^3-5212.7I^2+724.2I+9085.6(0\&le;I\&le;1.5)\\ 12040(I>1.5)\end{array}\right.$

The relation of electric current and bump leveller natural frequency is recorded, according to formula by laboratory data can be derived from k=(2 π f) ²m, laboratory data is as follows: (absorber mass m is 0.4kg)

Electric current I	0	0.5	1	1.5	2
						Natural frequency	23.98	25.47	27.03	27.5	27.62
Rigidity	9085.6	10249.8	11543.8	11948.8	12053.3

Fig. 8 is the matched curve relation (being applicable to electric current is 0 ~ 1.5A) of electric current and rigidity, and under normal circumstances, rigidity and current relationship should be a hysteresis loop.Fig. 9 is compound dynamic vibration absorber amplitude-versus-frequency curve under different electric current, and electric current is respectively 0A from left to right, 0.5A, 1A, 1.5A.

The design has widened effective vibration damping frequency band further relative to existing variation rigidity bump leveller and variable mass bump leveller, there is important engineer applied be worth, concrete frequency band widens effect as shown in Figure 7, wherein, a () widens design sketch for quality adjustment frequency band, b () widens design sketch for stiffness tuning frequency band, (c) regulates frequency band to widen design sketch for rigidity quality simultaneously.

Basic ideas of the present invention utilize intellectual material-magnetic rheology elastic body as elastic element, regulates rigidity by the difference changing magnetic field residing for material; Utilize liquid in bump leveller fluid box number to change the effective mass of bump leveller, the final natural frequency changing bump leveller.Its working principle is summarized as follows:

By noted earlier, bump leveller natural frequency is wherein m and k is respectively effective mass and the rigidity of bump leveller.If the minimum rigidity of this bump leveller, namely not adding rigidity during electric current, is k _min, maximum rigidity, rigidity when namely added electric current is maximum in effective coverage is k _max; The minimum value of variable-quality is m _min, maximum value is m _min+ Δ m, wherein Δ m is mass-adjustable.Known according to above-mentioned bump leveller calculation on Natural Frequency formula, the minimum and maximum natural frequency of the design is respectively therefore effective vibration damping frequency band of the design is compare with existing self-adapting type bump leveller, the molecule in natural frequency relation and denominator can be regulated in the present invention simultaneously, further increase the scope of effective damping frequency.When excited frequency extraneous suffered by compound dynamic vibration absorber changes, the signal of collection is passed to computer controlled system 15 through charge amplifier 16 by acceleration transducer 11, computer controlled system 15 by signal through fft, try to achieve extraneous excited frequency, with the Quality Control Strategy of above-mentioned proposition, in conjunction with the relation of elastomer rigidity and electric current, determine the rigidity that bump leveller is final and quality, current signal is regulated with this, controllable electric power 14 Received signal strength, export to field coil 5 optimal current in time, the rigidity of magnetic rheology elastic body 6 is regulated; Regulate the electric current of being defeated by motor 17 simultaneously, make liquor pump 18 pump into or pump liquid, regulate the effective mass of bump leveller with this.Through the natural frequency of above procedure regulation bump leveller, realize the tracking of bump leveller natural frequency excited frequency to external world, reach the best vibration damping to compound dynamic vibration absorber.

Claims (5)

1. a controlling method for the compound dynamic vibration absorber that natural frequency is adjustable, is characterized in that, described compound dynamic vibration absorber comprises: actuator, signal gathering unit and control system (15);

Actuator comprises: be arranged at the rigidity adjustable elements (1) on vibrating object, rigidity adjustable elements (1) is provided with fixed mass unit (9), fixed mass unit (9) is provided with fluid box (10), (10) are connected with water supply installation to fluid box; Wherein, rigidity adjustable elements (1) comprises the U-shaped pedestal (4) be arranged on vibrating object, U-shaped pedestal (4) is provided with the field coil (5) for generation of magnetic field, the opening of U-shaped pedestal (4) is provided with a pair clamping plate (7) by installing pretension bolt (3), absorber block (2) is clamped with by magnetic rheology elastic body (6) between clamping plate (7), form a closed magnetic conductive loop, fixed mass unit (9) is installed on absorber block (2);

Signal gathering unit comprises: be installed on for the acceleration transducer (11) bump leveller being carried out to vibration signals collecting, the flow transducer (13) be connected with water supply installation and charge amplifier (16) on fixed mass unit (9), the output terminal of acceleration transducer (11) is connected with the input end of charge amplifier (16); Charge amplifier (16) is connected with the input end of control system (15) with the output terminal of flow transducer (13);

The output terminal of control system (15) is connected with controllable electric power (14) and water supply installation, and the output terminal of controllable electric power (14) is connected with field coil (5);

Said method comprising the steps of:

1) extraneous excited frequency ω suffered by compound dynamic vibration absorber, is obtained;

2), set vibration damping frequency band as and by the vibration damping frequency band quartering, the end points of its quartering frequency band is designated as ω respectively ₁, ω ₂, ω ₃, ω ₄, ω ₅, wherein:

First frequency range is: [ω ₁, ω ₂], namely

Second frequency range is: [ω ₂, ω ₃], namely

3rd frequency range is: [ω ₃, ω ₄], namely

4th frequency range is: [ω ₄, ω ₅], namely

In formula, k _minfor compound dynamic vibration absorber minimum rigidity, namely do not add rigidity during electric current, k _maxfor compound dynamic vibration absorber maximum rigidity, namely add electric current maximum time rigidity, m _minfor the minimum value of variable-quality, m is the quality of fixed mass unit, and Δ m is variable-quality in the first frequency range fluid box, Δ m _x1be variable-quality in the second frequency range fluid box, Δ m _x2it is variable-quality in the 3rd frequency range fluid box;

Further, make:

$\left\{\begin{array}{c}\sqrt{\frac{k_{\max }}{m+\mathrm{\&Delta;}m}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x1}}}\\ \sqrt{\frac{k_{\max }}{m+{\mathrm{\&Delta;m}}_{x1}}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x2}}}\\ \sqrt{\frac{k_{\max }}{m+{\mathrm{\&Delta;m}}_{x2}}}=\sqrt{\frac{k_{\min }}{m}}\end{array}\right.---\left(3\right)$

?

$\left\{\begin{array}{c}\mathrm{\&Delta;}m=\frac{k_{max}^3\&times;m}{k_{\min }^3}-m\\ {\mathrm{\&Delta;m}}_{x1}=\frac{k_{max}^2\&times;m}{k_{\min }^2}-m\\ {\mathrm{\&Delta;m}}_{x2}=\frac{k_{\max }\&times;m}{k_{\min }}-m\end{array}\right.---\left(4\right)$

3), make:

$\left\{\begin{array}{c}{\mathrm{\&omega;}}_1=\sqrt{\frac{k_{\min }}{m_{\min }+\mathrm{\&Delta;}m}}\\ {\mathrm{\&omega;}}_2=\sqrt{\frac{k_{\min }}{m+\mathrm{\&Delta;}m}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x1}}}\\ {\mathrm{\&omega;}}_3=\sqrt{\frac{k_{\max }}{m+{\mathrm{\&Delta;m}}_{x1}}}=\sqrt{\frac{k_{\min }}{m+{\mathrm{\&Delta;m}}_{x2}}}\\ {\mathrm{\&omega;}}_4=\sqrt{\frac{k_{\max }}{m+{\mathrm{\&Delta;m}}_{x2}}}=\sqrt{\frac{k_{\min }}{m}}\\ {\mathrm{\&omega;}}_5=\sqrt{\frac{k_{\max }}{m}}\end{array}\right.---\left(5\right);$

4), determine frequency band division relation after, in bump leveller vibration damping frequency band, the interior variable-quality m of fluid box (10) _xcontrol adopt following control strategy:

$m_x=\left\{\begin{array}{c}\mathrm{\&Delta;}m\mathrm{.......................}{\mathrm{\&omega;}}_1\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_2\\ {\mathrm{\&Delta;m}}_{x1}\mathrm{....................}{\mathrm{\&omega;}}_2\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_3\\ {\mathrm{\&Delta;m}}_{x2}\mathrm{....................}{\mathrm{\&omega;}}_3\&le;\mathrm{\&omega;}<{\mathrm{\&omega;}}_4\\ \mathrm{0......................}{\mathrm{\&omega;}}_4\&le;\mathrm{\&omega;}\&le;{\mathrm{\&omega;}}_5\end{array}\right.---\left(6\right)$

5), control system (15) extraneous excited frequency ω suffered by obtained compound dynamic vibration absorber, and the control strategy corresponding to vibration damping frequency band, controls water supply installation and injects fluid box (10) or export the water yield; And, control system (15) obtains rigidity needed for bump leveller, the relation of rigidity and electric current needed for bump leveller, determine the required electric current applied, simultaneously according to the electric current of required applying, control signal is passed to controllable electric power (14), the electric current flowing to field coil (5) is regulated after controllable electric power (14) reception control signal, fine tuning is carried out to rigidity, by rigidity fine tuning, realizes the tracking of frequencies omega to external world.

2. the controlling method of the compound dynamic vibration absorber that natural frequency according to claim 1 is adjustable, is characterized in that, suffered by the compound dynamic vibration absorber of described acquisition, the process of extraneous excited frequency ω is:

Charge amplifier (16) receives the acceleration signal transmitted by acceleration transducer (11), degree of will speed up signal changes charge signal into and sends control system (15) to, control system (15) obtains extraneous excited frequency ω suffered by compound dynamic vibration absorber through fft after receiving charge signal.

3. the controlling method of the compound dynamic vibration absorber that natural frequency according to claim 1 is adjustable, is characterized in that, described water supply installation comprises: liquor pump (18), liquid tank (19) and motor (17); Fluid box (10) is connected with liquor pump (18) by flexible pipe (12), liquor pump (18) is connected with liquid tank (19), one end of motor (17) is connected with liquor pump (18), and the other end of motor (17) is connected with the output terminal of control system (15).

4. the controlling method of the compound dynamic vibration absorber that the natural frequency according to claim 1 or 3 is adjustable, it is characterized in that, described fluid box (10) is divided into liquid cavity of resorption (21) and air epicoele (23) by piston (22), piston (22) is provided with spring (20), the other end of spring (20) is connected with the top of fluid box (10).

5. the controlling method of the compound dynamic vibration absorber that natural frequency according to claim 1 is adjustable, it is characterized in that, described U-shaped pedestal (4), pretension bolt (3), clamping plate (7) and absorber block (2) are high permeability material.