阅读说明：本技术 变转速螺旋桨轴系纵向和横向多模态振动控制装置及方法 (Longitudinal and transverse multi-mode vibration control device and method for variable-speed propeller shaft system ) 是由 黄修长 黎丰 苏智伟 华宏星 于 2019-11-12 设计创作，主要内容包括：本发明提供了一种变转速螺旋桨轴系纵向和横向多模态振动控制装置及方法,包括：供电装置静止端(1)、供电装置旋转端(2)、压电分流电路(3)和切换/扫频电路(4)；供电装置旋转端与压电分流电路连接在变转速螺旋桨轴系的转轴上,随所述转轴同步旋转,供电装置静止端设置在供电装置旋转端的外侧,切换/扫频电路与压电分流电路电连接,压电分流电路与供电装置旋转端电连接；其中,切换/扫频电路控制压电分流电路中的电感和电阻的值按照预设的规律周期性变化。本发明采用切换/扫频电路,可以不做系统辨识即可进行多模态控制、并且可以在变工况系统中任用。(The invention provides a longitudinal and transverse multi-mode vibration control device and method for a variable-speed propeller shaft system, which comprises the following steps: the device comprises a power supply device static end (1), a power supply device rotating end (2), a piezoelectric shunt circuit (3) and a switching/frequency sweeping circuit (4); the rotating end of the power supply device and the piezoelectric shunt circuit are connected to a rotating shaft of the variable-speed propeller shaft system and synchronously rotate along with the rotating shaft, the static end of the power supply device is arranged on the outer side of the rotating end of the power supply device, the switching/frequency sweeping circuit is electrically connected with the piezoelectric shunt circuit, and the piezoelectric shunt circuit is electrically connected with the rotating end of the power supply device; the switching/frequency sweeping circuit controls the values of the inductance and the resistance in the piezoelectric shunt circuit to periodically change according to a preset rule. The invention adopts the switching/frequency sweeping circuit, can carry out multi-mode control without system identification and can be used in a variable working condition system.)

1. A variable-speed propeller shafting longitudinal and transverse multi-mode vibration control device is characterized by comprising: the device comprises a power supply device static end (1), a power supply device rotating end (2), a piezoelectric shunt circuit (3) and a switching/frequency sweeping circuit (4);

the power supply device rotating end (2) and the piezoelectric shunt circuit (3) are connected to a rotating shaft of a variable-speed propeller shaft system and synchronously rotate along with the rotating shaft, the power supply device static end (1) is arranged on the outer side of the power supply device rotating end (2), the switching/frequency sweeping circuit (4) is electrically connected with the piezoelectric shunt circuit (3), and the piezoelectric shunt circuit (3) is electrically connected with the power supply device rotating end (2);

the switching/frequency sweeping circuit (4) controls the values of the inductance and the resistance in the piezoelectric shunt circuit (3) to periodically change according to a preset rule.

2. The longitudinal and transverse multi-modal vibration control device of a variable-speed propeller shaft system as claimed in claim 1, wherein the shunt circuit (3) comprises: the piezoelectric piece, the first negative capacitor, the second negative capacitor, the inductor and the resistor are connected in series;

the piezoelectric sheet is connected to the rotating shaft, the resistor, the inductor and the second negative capacitor are sequentially connected in series and are connected in series with the inherent capacitance of the piezoelectric sheet, the electromechanical coupling coefficient is enhanced, and the first negative capacitor is connected in parallel with the inherent capacitance of the piezoelectric sheet to offset the inherent capacitance of the piezoelectric sheet.

3. The longitudinal and transverse multi-modal vibration control device of a variable-speed propeller shaft system as claimed in claim 1, wherein the switching/frequency sweeping circuit (4) comprises: a switching circuit or a frequency sweep circuit;

a switching circuit: controlling the values of the inductance and the resistance in the piezoelectric shunt circuit (3) to periodically change in a step shape according to a preset rule;

the frequency sweeping circuit comprises: and the values of the inductance and the resistance in the piezoelectric shunt circuit (3) are controlled to smoothly and periodically change according to a preset rule.

4. The longitudinal and transverse multi-mode vibration control device of the variable-speed propeller shafting according to claim 3, wherein the switching circuit controls the switching time of different piezoelectric shunt circuit branches by a single chip microcomputer, so that the values of the inductance and the resistance in the piezoelectric shunt circuit (3) are controlled to be changed in a step-shaped periodic manner according to a preset rule.

5. The longitudinal and transverse multi-modal vibration control device of the variable-speed propeller shaft system as claimed in claim 3, wherein the frequency sweeping circuit is a synthetic impedance circuit implemented by a Dspace control platform or a DSP circuit, so that the equivalent is a smooth periodic variation of the values of the inductance and the resistance in the piezoelectric shunt circuit (3) according to a preset rule.

6. The device for controlling longitudinal and transverse multi-modal vibration of a shafting of a variable-speed propeller shaft according to claim 3, wherein the sweep circuit determines the lower limit value ω according to the natural frequency of the required control frequency band and the desired control effect₀And an upper limit value omega₁Frequency of sweep f_sAnd a sweep index p, whereby the natural frequency is varied in such a way that the sweep variation image regularly covers the frequency image omega in the switching circuit_sw(t)＝ω₀+(ω₁-ω₀)sin(2πf_st)^pFrequency of sweep frequency f_sThe frequency sweep angular frequency is 2 pi f determined by a kinetic energy power spectral density ratio method_s；

The relation between the natural frequency of the circuit and the optimal inductance resistance value is found, the inductance value and the resistance value are expressed by the natural frequency of the circuit, and when the natural frequency of the circuit changes, the inductance resistance also changes along with the change of the natural frequency of the circuit, so that the continuous change is realized. The inductance varies in the following manner:

in the formula

In subcircuits C₂＝C_s/δ_opt，C₁Selected according to the actual situation, usually according to C₁＝0.55C_p，C_pIs the inherent capacitance of the piezoelectric patch;

finding the relation between the optimal resistance and the frequency change, knowing the optimal inductance and capacitance value at each order of natural frequency, obtaining the optimal resistance at each order of natural frequency by a kinetic energy power spectral density ratio method, and determining the lower limit value omega of the natural frequency₀And an upper limit value omega₁And performing linear fitting on the optimal discrete points of the resistance and inductance parameters of each order of natural frequency between the frequencies to obtain the relationship between the resistance and the inductance:

R_s(t)＝k₀+k₁L_s(t)

mixing L with_s(t) substituting the above formula to obtain the resistance value R_sVariation with time t:

in the formula k₀、k₁The coefficients obtained for the linear fit.

7. The device for controlling longitudinal and transverse multi-modal vibration of a variable-speed propeller shaft as claimed in claim 6, wherein the frequency f is swept_sControlling the length of the sweep frequency period, wherein the larger the numerical value is, the shorter the period is; the sweep index p controls the width of the peak value of the sine wave, and the larger the value, the narrower the width.

8. The longitudinal and transverse multi-modal vibration control device of the variable-speed propeller shaft system as recited in claim 6, wherein the value of the sweep index p comprises 4.

9. The device for controlling longitudinal and transverse multi-modal vibration of a variable-speed propeller shaft as claimed in claim 2, wherein said piezoelectric plates are operated at d₃₁Mode(s).

10. A longitudinal and transverse multi-mode vibration control method for a variable-speed propeller shaft system is characterized in that the longitudinal and transverse multi-mode vibration control device for the variable-speed propeller shaft system is adopted to control longitudinal and transverse multi-mode vibration of the variable-speed propeller shaft system according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of ship vibration control, in particular to a longitudinal and transverse multi-mode vibration control device and method for a variable-speed propeller shaft system.

Background

The propeller rotates in an uneven unsteady flow field, generates fundamental frequency and frequency multiplication exciting force line spectrum components related to rotating speed and blade number and random broadband components which basically and gradually attenuate along with frequency while generating static thrust, and the fundamental frequency and frequency multiplication exciting force line spectrum components and the random broadband components generate underwater sound radiation by forcing the ship structure to vibrate through shafting transmission; the latter will excite the characteristic modes of the propeller-shafting-hull coupled system, both of which will form prominent characteristic frequency spectrums, which are concentrated between 10Hz and 200 Hz.

The dynamic vibration absorber has small influence on the natural frequency of the propulsion shafting, and does not need to be connected into the shafting to bear large static thrust, but if a passive vibration absorbing measure is adopted, the required quality cost is higher because the controlled frequency of the propulsion shafting is low; a single conventional vibration absorber can only have a suppression effect for a certain order of mode; and the large natural frequency of the propeller-shafting-hull coupling system changes at different rotating speeds, which provides great challenges for the practical application of the dynamic vibration absorber. The invention provides a variable-rotating-speed shafting multi-mode semi-passive control vibration transfer control method based on a time-varying piezoelectric shunt circuit based on the principle of negative stiffness dynamic vibration absorption. When the thrust shaft rotates underwater, under the action of the wide-band force of the propeller, the amplification of force can be generated at the longitudinal vibration mode, the transverse vibration mode or the vibration mode of the propeller, so that a plurality of peak values of longitudinal and transverse transmission force transmitted to the thrust bearing are generated, and the inherent modes of the propeller-shafting-hull coupling system change at different rotating speeds.

The invention mainly solves the following technical problems: the requirements of time-varying characteristics and multi-mode control of an underwater shafting are met.

The patent with publication number CN104590528A discloses a longitudinal vibration control device of a boat propulsion shafting based on piezoelectric stack-hydraulic micro-displacement amplification, which comprises an axial vibration measurement system, a thrust pulsation controller, a power amplifier and a displacement control execution mechanism, which are connected in sequence by signals, wherein the displacement control execution mechanism comprises: the piezoelectric stack is used for receiving the electric signal sent by the power amplifier and generating corresponding output displacement; the hydraulic micro-displacement amplifier comprises a hydraulic amplification cavity with openings at two ends, two pistons with different sizes are respectively matched with two ends of the hydraulic amplification cavity in a sealing mode, the large piston acts with the displacement output end of the piezoelectric stack, and the small piston acts with a thrust bearing of a boat propulsion shafting through a slide valve core.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a longitudinal and transverse multi-mode vibration control device and method for a variable-speed propeller shaft system.

The invention provides a longitudinal and transverse multi-mode vibration control device for a variable-speed propeller shaft system, which comprises: the device comprises a power supply device static end 1, a power supply device rotating end 2, a piezoelectric shunt circuit 3 and a switching/frequency sweeping circuit 4;

the rotating end 2 of the power supply device and the piezoelectric shunt circuit 3 are connected to a rotating shaft of a variable-speed propeller shaft system and synchronously rotate along with the rotating shaft, the static end 1 of the power supply device is arranged on the outer side of the rotating end 2 of the power supply device, the switching/frequency sweeping circuit 4 is electrically connected with the piezoelectric shunt circuit 3, and the piezoelectric shunt circuit 3 is electrically connected with the rotating end 2 of the power supply device;

the switching/frequency sweeping circuit 4 controls the values of the inductance and the resistance in the piezoelectric shunt circuit 3 to periodically change according to a preset rule.

Preferably, the shunt circuit 3 comprises: the piezoelectric piece, the first negative capacitor, the second negative capacitor, the inductor and the resistor are connected in series;

the piezoelectric sheet is connected to the rotating shaft, the resistor, the inductor and the second negative capacitor are sequentially connected in series and are connected in series with the inherent capacitance of the piezoelectric sheet, the electromechanical coupling coefficient is enhanced, and the first negative capacitor is connected in parallel with the inherent capacitance of the piezoelectric sheet to offset the inherent capacitance of the piezoelectric sheet.

Preferably, the switching/frequency sweeping circuit 4 comprises: a switching circuit or a frequency sweep circuit;

a switching circuit: controlling the values of the inductor and the resistor in the piezoelectric shunt circuit 3 to periodically change in a step shape according to a preset rule;

the frequency sweeping circuit comprises: and controlling the values of the inductor and the resistor in the piezoelectric shunt circuit 3 to smoothly and periodically change according to a preset rule.

Preferably, the switching circuit controls the switching time of different branches by a single chip, so as to control the values of the inductance and the resistance in the piezoelectric shunt circuit 3 to periodically change in a step shape according to a preset rule.

Preferably, the frequency sweeping circuit realizes a synthetic impedance circuit through a Dspace control platform or a DSP circuit, so that the values of the inductance and the resistance in the equivalent piezoelectric shunt circuit 3 smoothly and periodically change according to a preset rule.

Preferably, the frequency sweep circuit determines the lower limit ω according to the natural frequency of the frequency band to be controlled and the desired control effect₀And an upper limit value omega₁Frequency of sweep f_sAnd sweep index^pSo that the natural frequency is changed in such a way that the frequency sweep change image covers the frequency image omega in the switching circuit regularly_sw(t)＝ω₀+(ω₁-ω₀)sin(2πf_st)^pFrequency of sweep frequency f_sThe frequency sweep angular frequency is 2 pi f determined by a kinetic energy power spectral density ratio method_s；

The relation between the natural frequency of the circuit and the optimal inductance resistance value is found, the inductance value and the resistance value are expressed by the natural frequency of the circuit, and when the natural frequency of the circuit changes, the inductance resistance also changes along with the change of the natural frequency of the circuit, so that the continuous change is realized. The inductance varies in the following manner:

in the formula C_s＝C_p-C₁，

The modal stiffness of the piezoelectric sheet in a short circuit state; k is modal stiffness; k is a radical of_ijThe electromechanical coupling coefficient of the j-direction force and the i-direction electric field is k₃₁；

In subcircuits C₂＝C_s/δ_opt，C₁Selected according to the actual situation, usually according to C₁＝0.55C_p，C_pIs the inherent capacitance of the piezoelectric patch;

finding the relation between the optimal resistance and the frequency change, knowing the optimal inductance and capacitance value at each order of natural frequency, obtaining the optimal resistance at each order of natural frequency by a kinetic energy power spectral density ratio method, and determining the lower limit value omega of the natural frequency₀And an upper limit value omega₁And performing linear fitting on the optimal discrete points of the resistance and inductance parameters of each order of natural frequency between the frequencies to obtain the relationship between the resistance and the inductance:

R_s(t)＝k₀+k₁L_s(t)

mixing L with_s(t) substituting the above formula to obtain the resistance value R_sVariation with time t:

in the formula k₀、k₁The coefficients obtained for the linear fit.

Preferably, the frequency of the sweep f_sControlling the length of the sweep frequency period, wherein the larger the numerical value is, the shorter the period is; index of frequency sweep^pThe width of the sine wave peak is controlled, and the larger the value is, the narrower the width is.

Preferably, the sweep index^pValues include 4.

Preferably, the piezoelectric patch operates at d₃₁Mode(s).

According to the longitudinal and transverse multi-mode vibration control method for the variable-speed propeller shaft system, the longitudinal and transverse multi-mode vibration control device for the variable-speed propeller shaft system is adopted to perform longitudinal and transverse multi-mode vibration control on the variable-speed propeller shaft system.

Compared with the prior art, the invention has the following beneficial effects:

the invention adopts the switching/frequency sweeping circuit, can carry out multi-mode control without system identification and can be used in a variable working condition system.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a dual negative capacitance piezoelectric shunt circuit of the present invention;

FIG. 3 is a synthesized impedance diagram of the equivalent double negative capacitance circuit of the switching/frequency sweeping circuit of the present invention;

FIG. 4 illustrates the effect of the switching circuit of the present invention on the resistance and inductance adjustment;

fig. 5 shows the effect of the frequency sweep circuit of the present invention on the resistance and inductance adjustment.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

As shown in fig. 1, the present invention provides a longitudinal and transverse multi-modal vibration control device for a variable-speed propeller shaft system, comprising: the device comprises a power supply device static end 1, a power supply device rotating end 2, a piezoelectric shunt circuit 3 and a switching/frequency sweeping circuit 4.

The rotating end 2 of the power supply device and the piezoelectric shunt circuit 3 are connected to a rotating shaft of a variable-speed propeller shaft system and synchronously rotate along with the rotating shaft, the static end 1 of the power supply device is arranged on the outer side of the rotating end 2 of the power supply device, the switching/frequency sweeping circuit 4 is electrically connected with the piezoelectric shunt circuit 3, and the piezoelectric shunt circuit 3 is electrically connected with the rotating end 2 of the power supply device; the switching/frequency sweeping circuit 4 controls the values of the inductance and the resistance in the piezoelectric shunt circuit 3 to periodically change according to a preset rule.

As shown in fig. 2, the shunt circuit 3 includes: a piezoelectric sheet 31, a first negative capacitor 32, a second negative capacitor 33, an inductor 34, and a resistor 35. The piezoelectric sheet 31 is connected to the rotating shaft, the resistor 35, the inductor 34 and the second negative capacitor 33 are sequentially connected in series and are connected in series with the inherent capacitance of the piezoelectric sheet 31 to enhance the electromechanical coupling coefficient, and the first negative capacitor 32 is connected in parallel with the inherent capacitance of the piezoelectric sheet 31 to offset the inherent capacitance of the piezoelectric sheet 31.

The piezoelectric sheet 31 is adhered to the surface of the rotating shaft and works at d₃₁The mode is that in order to improve the electromechanical coupling coefficient of a required control mode, the piezoelectric sheets are arranged at the maximum strain position of the required control mode, the number of the piezoelectric sheets is at least more than 20, the piezoelectric sheets are adhered to corresponding positions on the propulsion shaft system by using a high-performance two-component epoxy resin adhesive in a mode of winding a circle around the propulsion shaft system, and the propeller excitation force is longitudinal and transverse coupling excitation force, so that the piezoelectric sheets can simultaneously measure axial strain and bending strain, and the method is suitable for simultaneously controlling longitudinal and transverse vibration transmission.

The effectiveness of the double negative capacitance shunt circuit is as follows: -C₁The inherent capacitance of the piezoelectric sheet can be offset, and the electromechanical coupling coefficient is enhanced; L-R-C₂The electromechanical coupling coefficient can be further enhanced by the circuit, and the stability margin is improved. And determining the optimal RLC parameters of the double-negative-capacitance piezoelectric shunt circuit through the optimal parameter values of the RLC series circuit.

The switching/frequency sweeping circuit 4 includes: a switching circuit or a frequency sweep circuit;

a switching circuit: controlling the values of the optimal inductance and resistance under each order of natural frequency in the piezoelectric shunt circuit 3 to periodically change in a step shape according to a preset rule; the switching circuit is controlled by a single chip microcomputer (or a DSP circuit) to switch time of different branches, so that values of an inductor 34 and a resistor 35 in the piezoelectric shunt circuit 3 are controlled to change in a stepped periodic manner according to a preset rule.

The switching circuit needs to switch different external circuits at appropriate time due to circuit elements (inductor 34, resistor 35, negative capacitance-C)₁And a negative capacitance-C₂) Different parameters and different energy storage. The piezoelectric patch generates voltage under a strain state, and in order to avoid the sudden change of external circuit voltage and the impact of the voltage of the piezoelectric patch, the circuit is switched when the piezoelectric patch is not stressed (namely, the voltage at two ends of the piezoelectric patch is zero). Thus corresponding to a zero input response after each switch. The switching time is determined as follows: when in useWhen the input current system is forced to vibrate, the current is represented by the on-off of free response and the special-off of the input current, a certain time is needed to ensure that the free response attenuation reaches 63 percent, and a fixed time is also needed to ensure that the voltage at two ends of the piezoelectric plate is 0 when the circuit is switched, so that the impact is avoided and the effect of stable switching is achieved. According to the principle, the circuit conduction time corresponding to each mode can be obtained.

The frequency sweeping circuit comprises: and controlling the values of the inductor and the resistor in the piezoelectric shunt circuit 3 to smoothly and periodically change according to a preset rule. The frequency sweeping circuit realizes the synthesis of an impedance circuit through a Dspace control platform or a DSP circuit, so that the values of an inductor 34 and a resistor 35 in the equivalent double-negative-capacitance piezoelectric shunt circuit 3 smoothly and periodically change according to a preset rule.

The frequency sweep circuit determines the lower limit value omega according to the natural frequency of the frequency band required to be controlled and the expected control effect₀And an upper limit value omega₁Frequency of sweep f_sAnd sweep index^pSo that the natural frequency is changed in such a way that the frequency sweep change image covers the frequency image omega in the switching circuit with a certain regularity_sw(t)＝ω₀+(ω₁-ω₀)sin(2πf_st)^pFrequency of sweep frequency f_sDetermined by kinetic energy power spectral density ratio method, i.e. sweep angular frequency of 2 pi f_s。

The relation between the natural frequency of the circuit and the optimal inductance resistance value is found, the inductance value and the resistance value are expressed by the natural frequency of the circuit, and when the natural frequency of the circuit changes, the inductance resistance also changes along with the change of the natural frequency of the circuit, so that the continuous change is realized. The inductance varies in the following manner:

in the formula C_s＝C_p-C₁，

The modal stiffness of the piezoelectric sheet in a short circuit state; k is modal stiffness; k is a radical of_ijThe electromechanical coupling coefficient of the j-direction force and the i-direction electric field is k₃₁。

In subcircuits C₂＝C_s/δ_opt，C₁Selected according to the actual situation, usually according to C₁＝0.55C_p。C_pIs the inherent capacitance of the piezoelectric patch.

And finding the relation between the optimal resistance and the frequency change, and obtaining the optimal resistance at each order of natural frequency by knowing the optimal inductance and capacitance at each order of natural frequency through a kinetic energy power spectral density ratio method. For lower limit value omega of natural frequency₀And an upper limit value omega₁And performing linear fitting on the optimal discrete points of the resistance and inductance parameters of each order of natural frequency between the frequencies to obtain the relationship between the resistance and the inductance:

R_s(t)＝k₀+k₁L_s(t)

mixing L with_s(t) substituting the above formula to obtain the resistance value R_sVariation with time t:

in the formula k₀、k₁The coefficients obtained for the linear fit.

Frequency sweep frequency f_sControlling the length of the sweep frequency period, wherein the larger the numerical value is, the shorter the period is; index of frequency sweep^pControlling the peak width of the sine wave, the larger the value is, the narrower the width is, and the general sweep index^pThe value is 4.

When the thrust shaft rotates underwater, under the action of the wide belt force of the propeller, the amplification of the force can be generated at the first-order longitudinal vibration mode of the shaft system or the first-order in-phase vibration mode of the propeller, so that the peak value of the force transmitted to the thrust bearing is generated. -C₁The inherent capacitance of the piezoelectric sheet can be offset, and the electromechanical coupling coefficient is enhanced; L-R-C₂The circuit can further enhance the electromechanical coupling coefficient and improve the stability margin。

The following is the determination of specific parameters.

First, the optimal parameters of resistance, negative capacitance and inductance corresponding to the mode to be controlled at each stage are obtained. The optimal parameters of the circuit RLC considered by the method can be determined on the basis of the optimal parameters of the RLC series circuit. A first negative capacitor 32 in the first branch is connected with the inherent capacitance 31 of the piezoelectric sheet in parallel to offset the inherent capacitance of the piezoelectric sheet; the second negative capacitor 33 in the second branch forms an RLC circuit with an inductor 34 and a resistor 35. The optimal parameters of the RLC series circuit are:

in the formula

The modal stiffness of the piezoelectric sheet in a short circuit state; k is modal stiffness; k is a radical of_ijThe electromechanical coupling coefficient of j-direction force and i-direction electric field is k₃₁；

The nth order natural frequency of the piezoelectric system in a short circuit state.

C₁Selected according to the actual situation, usually according to C₁＝0.55C_p。C_pIs the inherent capacitance of the piezoelectric patch.

In the double-negative-capacitance piezoelectric shunt circuit of the patent, the inherent capacitance of the piezoelectric sheet is represented as C due to the cancellation effect of the first negative capacitance_s＝C_p-C₁Therefore, the second negative capacitance optimal parameter in the second branch is C₂＝C_s/δ_opt. The optimal inductance in the second branch is:

optimum resistance value R of each order_sDetermined by kinetic energy power spectral density ratio method, in particular

In the formula, S_kThe power spectral density of kinetic energy is adopted when a piezoelectric shunt circuit is adopted; omega_a,ω_bDetermining a lower limit value and an upper limit value of a frequency band to be controlled; s_KsAnd (omega) represents the kinetic energy power spectral density of the structure when the external circuit is short-circuited.

The dynamic power spectral density ratio method is a trial-and-error method, the peak of the dynamic power spectral density appears near the natural frequency of the structure, the amplitude of the power spectral density can be effectively weakened by adjusting the numerical values of elements such as resistance, inductance and capacitance or the frequency sweep frequency, the vibration damping effect of the piezoelectric shunt circuit is judged by comparing the ratio of the power spectral density after piezoelectric shunt and the integral area of the power spectral density near the peak under the external circuit short circuit state, and the smaller the result is, the better the corresponding parameter effect is. And changing the element parameters to obtain the ratio of the integral areas corresponding to the frequency ranges, wherein the minimum ratio is the optimal element parameter. The switching or frequency sweeping circuit 4 is a switching circuit or a frequency sweeping circuit. The switching circuit controls the switching time of different branches by a single chip, controls the values of the inductor 34 and the resistor 35 to periodically change in a step-like manner in a given period, or realizes the step-like change rule of the inductor 34 and the resistor 35 by using a synthetic impedance circuit. The sweep frequency circuit adopts a Dspace control platform or a DSP circuit to synthesize the equivalent inductance 34 and resistance 35 values of the impedance circuit, so that the inductance 34 and resistance 35 values can be regularly and smoothly changed periodically in a given period.

Fig. 3 is a synthesized impedance diagram of the equivalent double negative capacitance circuit of the switching/frequency sweeping circuit of the present invention. In the synthetic impedance diagram, 2 instrument amplifiers INA are provided, wherein a resistor R is connected between the positive input end of INA1 and the output end of INA2, the output end of INA1 is connected with the positive electrode of the analog-digital conversion end of the DSP, and the negative electrode of the analog-digital conversion end of the DSP is grounded; digital-to-analog of DSPThe positive electrode and the negative electrode of the conversion end are respectively connected with the positive electrode and the negative electrode input end of the INA 2; the input voltage is adjusted by the instrumentation amplifier INA1, the required impedance is realized in the DSP, and the voltage is restored by the INA 2. With double negative capacitance shunt circuits Rs, Ls and C in this context₁、C₂For example, a gain to be realized in the DSP can be obtained as

For the switching circuit, the key is to control the conduction duration of the circuit corresponding to each mode of the switching circuit: different external circuits switched in the switching circuit have different stored energy due to different circuit element parameters. The piezoelectric patch generates voltage under a strain state, and in order to avoid the sudden change of the voltage of an external circuit and the impact of the voltage of the piezoelectric patch, the circuit is switched when the piezoelectric patch is not stressed (namely the voltage at the circuit end of the piezoelectric patch is zero), which is equivalent to zero input response. When there is an input current, the system is forced to vibrate, and the current is represented by the on solution of free response and the special solution of the input current. That is to say, when the circuit is switched, the initial state of the circuit changes, a certain time is needed to ensure that the free response attenuation reaches 63%, and in addition, a fixed time is needed to ensure that the voltage of the piezoelectric patch is 0 at the line end when the circuit is switched, so that the impact is avoided, and the effect of stable switching is achieved. And obtaining the conduction time of the circuit corresponding to each mode according to the principle. The required time of the switching circuit is ignored, and fig. 4 shows the effect of the switching circuit 4 of the present invention on adjusting the resistance and inductance of the external circuit.

For the parameters of the frequency sweep circuit, the following are determined on the basis of the switching circuit: determining a lower limit value omega according to the natural frequency of a frequency band required to be controlled and the expected control effect in the frequency sweep circuit₀And an upper limit value omega₁Frequency of the sweep f_sAnd sweep index^pTherefore, the natural frequency of the circuit changes according to the following mode, so that the frequency sweep change image covers the frequency image in the switching circuit regularly:

ω_sw(t)＝ω₀+(ω₁-ω₀)sin(2πf_st)^p

in the formula, frequency sweep frequency f_sThe method is determined by a kinetic energy power spectral density ratio method:

in the formula, S_kThe power spectral density of kinetic energy is adopted when a piezoelectric shunt circuit is adopted; omega_a,ω_bDetermining a lower limit value and an upper limit value of a frequency band to be controlled; s_Ks(ω) represents the power spectral density of the structure when the external circuit is shorted.

The relation between the natural frequency of the circuit and the optimal inductance resistance value is found, the inductance resistance value is represented by the natural frequency of the circuit, and when the natural frequency of the circuit changes, the inductance resistance changes along with the change of the natural frequency of the circuit, so that continuous change is realized. The inductance varies in the following manner:

and finding the relation between the optimal resistance and the frequency change, and obtaining the optimal resistance at each order of natural frequency by knowing the optimal inductance and capacitance at each order of natural frequency through a kinetic energy power spectral density ratio method. For lower limit value omega of natural frequency₀And an upper limit value omega₁And performing linear fitting on the optimal discrete points of the resistance and inductance parameters of each order of natural frequency between the frequencies to obtain the relationship between the resistance and the inductance:

R_s(t)＝k₀+k₁L_s(t)

generally speaking, the frequency f of the sweep_sControlling the length of the sweep frequency period, wherein the larger the numerical value is, the shorter the period is; index of frequency sweep^pThe sine wave peak width is controlled, the larger the value is, the narrower the width is, and p is 4.

Fig. 5 shows the effect of the frequency sweep circuit 4 on the resistance and inductance adjustment. The invention also provides a longitudinal and transverse multi-mode vibration control method for the variable-speed propeller shaft system, which is used for performing longitudinal and transverse multi-mode vibration control on the variable-speed propeller shaft system by adopting the longitudinal and transverse multi-mode vibration control device for the variable-speed propeller shaft system.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.