Structural noise suppression system and method

Abstract

The invention discloses a structural noise suppression system and method.The system comprises an array composed of a plurality of independent vibration absorption units, and the array is used for being attached to a vibration structure to suppress structural noise; the vibration absorption unit comprises a vibration absorber and a shunt circuit; the vibration absorber at least comprises a piezoelectric element and is used for sensing vibration and outputting a voltage signal, and the shunt circuit is used for collecting the voltage signal and adjusting parameters of the shunt circuit according to the voltage signal, so that the resonant frequency of the vibration absorber is adjusted; wherein when the shunt circuit works, if the voltage signal is increased, the change trend of the current circuit parameter is maintained, and if the voltage signal is reduced, the circuit parameter is adjusted to change along the direction opposite to the current change trend. According to the system, the resonant frequency of the vibration absorber in the system is adjusted by adjusting parameters of the shunt circuit, the effect that the working frequency of the system actively follows the vibration frequency of the structure is achieved, the vibration absorption unit is simple in structure, and the working frequency band is easy to expand.

Description

Technical Field

[0001] This application relates to the field of structural noise reduction, and particularly to a structural noise suppression system and method. Background Art

[0002] Noise inside the aircraft cabin is a key factor affecting passenger comfort, and structural noise dominates. Structural noise originates from vibrations caused by engine vibrations, airflow impacts, and mechanical component movements, is transmitted into the cabin through rigid structures such as the fuselage frame, and radiates in the form of sound waves. Traditional passive noise reduction methods such as using sound-absorbing materials or damping layers can partially reduce noise, but they are heavy and have poor frequency adaptability, making it difficult to meet the requirements of modern aircraft for lightweight and adaptive noise reduction.

[0003] Currently, aircraft structural noise suppression technologies mainly include three categories: using passive vibration absorption materials and damping layers (such as the acoustic metamaterial wall panels disclosed in patent CN118323427A), using dynamic vibration absorbers (such as the multi-resonant point dynamic vibration absorbers disclosed in patent CN10521623A), and using in-cabin active noise reduction systems (such as the active control method disclosed in patent CN113674729A). Among them, the materials of the first type of technology significantly increase the aircraft load and cannot be dynamically adjusted according to the noise frequency. The second type of technology has a limited frequency adjustment range and requires manual adjustment during shutdown, making it difficult to adapt to broadband noise environments. The third type of technology requires additional power supply and in-cabin space, and has limited source suppression effect on structural noise. Therefore, there is an urgent need for a lightweight and frequency-adaptive structural noise suppression product. Summary of the Invention

[0004] Embodiments of this application provide a structural noise suppression system and method, which construct a piezoelectric system with piezoelectric elements as the core and achieve frequency-adaptive structural noise suppression through frequency shifting technology.

[0005] To solve the above technical problems, embodiments of this application disclose the following technical solutions:

[0006] On the one hand, a structural noise suppression system is provided, including: an array composed of multiple independent vibration absorption units for attaching to a vibrating structure to suppress structural noise; the vibration absorption unit includes a vibration absorber and a shunt circuit; the vibration absorber includes at least one piezoelectric element for sensing vibration and outputting a voltage signal, and the shunt circuit is used to collect the voltage signal and adjust the shunt circuit parameters according to the voltage signal, thereby adjusting the resonant frequency of the vibration absorber; wherein, when the shunt circuit is working, if the voltage signal becomes larger, the current change trend of the circuit parameters is maintained, and if the voltage signal becomes smaller, the circuit parameters are adjusted in the opposite direction to the current change trend.

[0007] Further, the vibration absorber includes protons, piezoelectric sheets, a substrate, and a rigid frame arranged in a stacked manner; the piezoelectric sheet is a piezoelectric element for sensing vibration and outputting a voltage signal through the piezoelectric effect, and the rigid frame is used to fit with the vibrating structure to transmit vibration signals; the initial resonance frequency of the vibration absorber is determined by the mass of the protons.

[0008] Furthermore, the substrate is made of a flexible film material, and the rigid frame fixes the edge of the substrate and transmits vibration signals.

[0009] Furthermore, the rigid frame is rigidly connected to the vibrating structure.

[0010] Further, the mass of the protons is adjustable, and different masses of protons correspond to different initial resonance frequencies of the vibration absorber.

[0011] Further, among multiple independent vibration absorption units, at least two protons with different masses are included to expand the working frequency band of the array.

[0012] Further, among multiple independent vibration absorption units, the protons of each vibration absorber are arranged in an arithmetic progression of mass.

[0013] Further, the shunt circuit includes a signal collector, a controller, and an adjustable negative capacitor; the signal collector is coupled to the piezoelectric element for collecting the voltage signal and converting the voltage signal into a digital signal; the controller is used to receive the digital signal and calculate the change amount of the adjustable negative capacitor according to the digital signal to output a control signal; the adjustable negative capacitor is connected in parallel with the piezoelectric element and is controlled by the controller to receive the control signal.

[0014] Further, the adjustable negative capacitor at least includes an adjustable resistor, a fixed resistor, an operational amplifier circuit, and a fixed capacitor; the fixed capacitor, the adjustable resistor, and the fixed resistor are connected in series across both ends of the piezoelectric element; the operational amplifier circuit is used to receive the voltage on the adjustable resistor and couple the amplification factor to the fixed capacitor; the controller changes the amplification factor of the operational amplifier circuit by adjusting the resistance value of the adjustable resistor, thereby changing the value of the adjustable negative capacitor.

[0015] Further, the shunt circuit adjusts the resonance frequency of the vibration absorber by using an absorption frequency shift algorithm; the absorption frequency shift algorithm is characterized in that the control signal output by the controller is a sequence signal with the same amplitude, and the sign of the (n + 1)-th control signal is determined by an AND operation logic, and the two operands of the AND operation logic are: the sign of the difference between the (n + 1)-th voltage signal and the n-th voltage signal, and the sign of the n-th control signal; where n is a natural number, and when n is 0, the sign of the control signal is preset to be positive.

[0016] Further, the adjustment increment of the adjustable negative capacitor is:

[0017] ΔC n+1= sgn(U n+1 - U n )·sgn(ΔC n )·K

[0018] where ΔC n is the nth adjustment increment of the adjustable negative capacitance, U n is the nth voltage signal, sgn is the sign function representing the sign of the variable in the brackets, and K is the preset amplitude.

[0019] Furthermore, the preset amplitude is convergently optimized through the PID algorithm to improve the adjustment speed of the resonance frequency of the vibration absorber.

[0020] On the other hand, the present application provides a structural noise suppression method applied to any of the above structural noise suppression systems, including: sensing the structural vibration signal through a piezoelectric element and generating a corresponding voltage signal; collecting the voltage signal; based on the change of the voltage signal, changing the resonance frequency of the vibration absorber by adjusting the circuit parameters of the shunt circuit; the resonance frequency of the vibration absorber matches the frequency of the vibration noise to absorb the vibration energy and suppress the structural noise.

[0021] Furthermore, based on the change of the voltage signal, changing the resonance frequency of the vibration absorber by adjusting the circuit parameters of the shunt circuit is achieved through the following steps: calculating the difference between the current voltage signal and the historical voltage signal; determining the increment of the adjustable negative capacitance according to the difference sign, the increment sign of the historical adjustable negative capacitance, and the preset amplitude; adjusting the resistance value of the adjustable resistor to change the amplification factor of the operational amplifier circuit, and further adjusting the value of the adjustable negative capacitance.

[0022] Furthermore, when the frequency of the structural vibration signal changes, the voltage signal acquisition is repeatedly performed and the adjustable negative capacitance is continuously adjusted to enable the resonance frequency of the vibration absorber to dynamically follow the frequency change of the structural vibration signal.

[0023] Furthermore, the adjustable range of the resonance frequency is 20% of the initial resonance frequency.

[0024] Furthermore, the amplitude of the voltage signal is the product of the amplitude of the structural vibration signal and the response amplitude of the vibration absorber. When the vibration absorber resonates with the structural vibration signal, the voltage signal reaches the maximum value.

[0025] The above technical solutions have at least the following advantages or beneficial effects: The vibration absorption unit composed of the shunt circuit and the vibration absorber can adaptively adjust the circuit parameters of the shunt circuit according to the change trend of the voltage signal generated by the piezoelectric element, so that the working frequency of the vibration absorption unit can follow the vibration frequency of the vibrating structure, making full use of the resonance effect to reduce the noise of the vibrating structure. The vibration absorption unit has a simple structure, does not require a complex damping layer, and multiple vibration absorption units can form an array to enhance the vibration absorption ability.

[0026] In the above technical solution, by performing proton mass configuration on the absorbers of multiple vibration absorption units, the following advantages or beneficial effects are also achieved: Multiple different proton masses can enable an array to absorb vibration noises in multiple frequency ranges, broadening the working frequency band range of the entire system.

[0027] In the above technical solution, the absorber includes protons, piezoelectric elements, a substrate, and a rigid frame, and the following advantages or beneficial effects are also achieved: The absorber has a thin, light, and flat structure, is easy to adhere to the surface of the vibrating structure, and does not require complex installation. Description of the Drawings

[0028] The technical solutions and other beneficial effects of the present application will become obvious by specifically describing the specific embodiments of the present application in conjunction with the drawings.

[0029] Figure 1 Schematic diagram of the structural noise suppression system provided by the present application;

[0030] Figure 2 Schematic diagram of the vibration absorption unit 100 provided by the present application;

[0031] Figure 3 Schematic diagram of the stacked structure of the absorber 110 provided by the present application;

[0032] Figure 4 Schematic diagram of the shunt circuit 120 provided by the present application;

[0033] Figure 5 Schematic diagram of the parameter control of the adjustable negative capacitor 123 provided by the present application;

[0034] Figure 6 Schematic diagram of the noise frequency - sound absorption coefficient provided by the present application;

[0035] Figure 7 Effect diagram of the vibration absorption frequency following provided by the present application;

[0036] Figure 8 Flowchart of the circuit parameter adjustment method provided by the present application.

[0037] Description of the reference numerals:

[0038] 100, vibration absorption unit; 110, absorber; 111, proton; 112, piezoelectric sheet; 113, substrate; 114, rigid frame; 120, shunt circuit; 121, signal collector; 122, controller; 123, adjustable negative capacitor; 1231, adjustable resistor; 1232, fixed resistor; 1233, operational amplifier circuit; 1234, fixed capacitor. Detailed Description of the Embodiments

[0039] In order to make the objectives, technical solutions, and beneficial effects of this application clearer, the following further elaborates on this application in conjunction with the accompanying drawings and specific implementation manners. It should be understood that the specific implementation manners described in this specification are only for explaining this application and not for limiting this application.

[0040] In the description of this application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the accompanying drawings. These are only for facilitating the description of this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to this application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of this application, "a plurality" means two or more, unless otherwise specifically defined.

[0041] In the description of this application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] In this application, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and diagonally above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "beneath", and "under" the second feature includes the first feature being directly below and diagonally below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0043] Figure 1 Schematic diagram of the structural noise suppression system provided for this application. As Figure 1As shown, the structure-borne noise suppression system provided by the present application includes an array composed of a plurality of independent vibration absorption units 100, which is used to fit to a vibrating structure to suppress structure-borne noise. In Figure 1 , the structure-borne noise suppression system is a square array composed of 9 independent vibration absorption units 100. However, those skilled in the art can arrange any number of independent vibration absorption units 100 into an array that matches the shape of the vibrating structure according to the actual surface of the vibrating structure. The number and arrangement of the vibration absorption units 100 in this embodiment do not limit the protection scope of the claims. Compared with traditional vibration absorption materials, the above array has a smaller mass and volume and can flexibly adapt to the surface shape of the vibrating structure.

[0044] Figure 2 FIG. is a schematic diagram of the vibration absorption unit 100 provided by the present application. Each vibration absorption unit 100 in the embodiment of the present application includes a vibration absorber 110 and a shunt circuit 120. Among them, the vibration absorber 110 includes at least one piezoelectric element for sensing vibration and outputting a voltage signal. The shunt circuit 120 is used to collect the voltage signal and adjust the circuit parameters of the shunt circuit 120 according to the voltage signal, so as to adjust the resonance frequency of the vibration absorber 110. When the natural frequency of the vibration absorber 110 matches the external excitation frequency, that is, the vibration frequency of the vibrating structure, its vibration amplitude reaches the peak, and the vibration mechanical energy is efficiently converted into electrical energy through the piezoelectric effect of the piezoelectric element. Based on this, it can be known that when the voltage signal output by the piezoelectric element becomes larger, it means that the energy absorbed by the piezoelectric system becomes larger. Therefore, the inventor of the present application designed an absorption frequency shift algorithm according to the correlation between the impedance of the piezoelectric element and the mechanical impedance for the piezoelectric structure of the above vibration absorption unit 100, and designed the shunt circuit 120 to work in the following mode: if the voltage signal output by the piezoelectric element increases, maintain the current trend of circuit parameter change; if the voltage signal output by the piezoelectric element decreases, adjust the circuit parameters in the opposite direction to the current change trend.

[0045] Figure 3 FIG. is a schematic diagram of the laminated structure of the vibration absorber 110 provided by the present application. Referring to Figure 1 , Figure 2 and Figure 3 , the vibration absorber 110 in the embodiment of the present application includes a proton 111, a piezoelectric sheet 112, a substrate 113 and a rigid frame 114 which are laminated. Among them, the piezoelectric sheet 112 is a piezoelectric element for sensing vibration and outputting a voltage signal through the piezoelectric effect. The rigid frame 114 is used to fit to the vibrating structure to transmit the vibration signal to the substrate 113 and the piezoelectric sheet 112, and the substrate 113 is a flexible film material. As Figure 3As shown by the dashed line in the figure, the rigid frame 114 fixes the edge of the substrate 113. The proton 111 and the fixed edge of the substrate 113 make the piezoelectric system become a resonator, which can generate a resonance phenomenon at a certain frequency. The resonance frequency of this resonator is related to the initial resonance frequency of the entire piezoelectric system and the circuit parameters electrically coupled to the piezoelectric element. Among them, the initial resonance frequency can be determined and adjusted by the mass of the proton 111. Different proton masses can correspond to different initial resonance frequencies, so that the entire resonator can correspondingly track and absorb the vibrations near the initial resonance frequency. When the rigid frame 114 is rigidly connected to a vibrating structure, such as a mounting section or a fuselage connected to an aircraft engine, the resonator can correspondingly absorb the noise caused by the main vibration frequency in a certain engine operating mode.

[0046] Comparison Figure 1 With Figure 3 The shown structural noise suppression system, the number of vibration absorbers 100 in both is different. Combining the principle and structure of the vibration absorber 110 in the above-mentioned vibration absorber 100, the present application also proposes a proton 111 mass configuration strategy for the two structural noise suppression systems. In one strategy, the masses of the protons 111 in multiple vibration absorbers 110 are the same, which is used to absorb the structural noise with a relatively narrow range of change in a certain vibration frequency. By increasing the number of protons 111 corresponding to this vibration frequency, the vibration absorption effect can be maximized. In another strategy, at least two vibration absorbers 110 with different proton 111 masses are included in multiple independent vibration absorber units 100, which is used to expand the noise frequency that the system can absorb, that is, to expand the working frequency band of the array. For example, among multiple independent vibration absorber units 100, the protons 111 of each vibration absorber 110 are configured in a way that the mass increases in an arithmetic progression.

[0047] Figure 4 It is a schematic diagram of the shunt circuit 120 provided by the present application. In this embodiment, the shunt circuit 120 includes a signal collector 121, a controller 122, and an adjustable negative capacitor 123. As Figure 4 shown, the signal collector 121 is coupled to the piezoelectric element. Combining Figure 2 With Figure 3 the embodiment shown, the piezoelectric element is, for example, a piezoelectric sheet 112. The signal collector 121 is coupled to both sides of the piezoelectric sheet 112, and is used to collect the voltage signal generated by the piezoelectric effect of the piezoelectric sheet 112 and convert the voltage signal into a digital signal. In different embodiments, the signal collector 121 can adopt an amplifier circuit or an analog-to-digital conversion circuit. In this embodiment, the two input terminals of the signal collector 121 are respectively the positive-phase input terminal and the inverting input terminal of the amplifier circuit. The controller 122 is used to receive the digital signal output by the signal collector 121 and calculate the change amount of the adjustable negative capacitor 123 according to the digital signal to output a control signal. The adjustable negative capacitor 123 is connected in parallel with the piezoelectric element and is controlled by the controller 122 to receive the control signal.

[0048] Reference Figure 4 , the adjustable negative capacitor 123 at least includes an adjustable resistor 1231, a fixed resistor 1232, an operational amplifier circuit 1233 and a fixed capacitor 1234. After the fixed capacitor 1234, the adjustable resistor 1231 and the fixed resistor 1232 are connected in series, they are connected to two input terminals of the signal collector 121, that is, in parallel to both ends of the piezoelectric element; the operational amplifier circuit 1233 is used to receive the voltage on the adjustable resistor 1231 and couple the amplification factor to the fixed capacitor 1234; the controller 122 changes the amplification factor of the operational amplifier circuit 1233 by adjusting the resistance value of the adjustable resistor 1231, thereby changing the value of the adjustable negative capacitor 123. That is, the adjustable resistor 1231 serves as a controlled element of the adjustable negative capacitor 123 and is controlled by the controller 122 to receive a control signal. It should be understood that in this embodiment, the circuit structure and method of the adjustable resistor 1231 serving as a controlled element of the adjustable negative capacitor 123 do not limit the independent claims of this embodiment. Any circuit that can realize the adjustable negative capacitor 123 being controlled by the controller 122 can be selected by those skilled in the art.

[0049] In the above embodiments, the shunt circuit 120 uses an absorption frequency shift algorithm to adjust the resonance frequency of the absorber 110. The absorption frequency shift algorithm is characterized in that the control signal output by the controller 122 is a sequence signal with the same amplitude, and the sign of the (n + 1)-th control signal is determined by an AND operation logic. The two operands of the AND operation logic are: the sign of the difference between the (n + 1)-th voltage signal and the n-th voltage signal, and the sign of the n-th control signal; where n is a natural number, and when n is 0, the sign of the control signal is preset to be positive. When the (n + 1)-th voltage signal is greater than the n-th voltage signal, if the sign of the n-th control signal is positive, the sign of the (n + 1)-th control signal is positive; if the sign of the n-th control signal is negative, the sign of the (n + 1)-th control signal is negative. That is, the change trend of the parameters of the shunt circuit 120 controlled by the controller 122 can keep the voltage signal increasing continuously, and the vibration absorption ability of the system increases continuously; when the (n + 1)-th voltage signal is less than the n-th voltage signal, if the sign of the n-th control signal is positive, the sign of the (n + 1)-th control signal is negative; if the sign of the n-th control signal is negative, the sign of the (n + 1)-th control signal is positive. That is, the change trend of the parameters of the shunt circuit 120 controlled by the controller 122 can curb the decrease of the voltage signal and improve the vibration absorption ability of the system.

[0050] Figure 5 It is a schematic diagram of parameter control of the adjustable negative capacitor 123 provided by this application. Based on the principle of the above absorption frequency algorithm, a specific adjustment of the parameters of the shunt circuit 120 can be realized by controlling the value of the adjustable negative capacitor 123. As Figure 5As shown, let the amplitude of the vibration signal of the vibration structure be A and the frequency be fi. After the vibration absorber 110 senses the vibration signal, the signal collector 121 collects the voltage across the piezoelectric element in the vibration absorber 110, and performs a difference operation on the nth voltage signal and the (n + 1)th voltage signal through sample and hold, and transmits the result of the difference operation to the controller 122. The controller 122 performs an adjustable negative capacitance 123 adjustment increment operation according to the result of the difference operation and the sign of the nth control signal. Its operation control formula is:

[0051] ΔC n+1 =sgn(U n+1 -U n )·sgn(ΔC n )·K

[0052] Where, ΔC n is the nth adjustment increment of the adjustable negative capacitance 123, U n is the nth voltage signal, sgn is the sign function, representing the sign of the variable in the parentheses, and K is the preset amplitude. In Figure 4 the illustrated embodiment, the nth adjustment increment ΔC n of the adjustable negative capacitance 123, that is, the variable of the negative capacitance, is realized by the controller 122 adjusting the adjustable resistor 1231. Combining Figure 4 with Figure 5 , when the controller 122 performs the (n + 1)th adjustment, the adjustable resistor 1231 is controlled by the control signal output by the controller 122, and the changed resistance value causes the voltage division with the fixed resistor 1232 to change, thereby realizing the change of the amplification factor of the operational amplifier circuit 1233, that is, the coefficient of the fixed capacitor 1234 changes. Since the shunt circuit 120 is electrically coupled to the piezoelectric element in the vibration absorber 110, the capacitance parameter of the shunt circuit 120 is coupled to the inherent capacitance of the piezoelectric element itself, thereby changing the impedance of the entire piezoelectric system, so that the parameter change of the shunt circuit 120 can be associated with the resonant frequency of the vibration absorber 110. In this embodiment, the preset amplitude K can also be converged and optimized through the PID (proportional-integral-derivative) algorithm to improve the adjustment speed of the resonant frequency of the vibration absorber 110, so that the vibration absorber 110 can be adjusted to the main vibration frequency in fewer adjustment times.

[0053] Figure 6 This is the noise frequency - sound absorption coefficient schematic diagram provided by the present application, showing the sound absorption coefficient curve of the vibration absorption unit 100 provided by the present application, as Figure 6As shown, in the legend, oc, sc, Cneg = 52 nF, Cneg = 54 nF, and Cneg = 56 nF respectively represent the sound absorption coefficients of the vibration absorption unit 100 when the shunt circuit 120 is open-circuited, short-circuited, and the parameters of the adjustable negative capacitor 123 are -52 nF, -54 nF, and -56 nF. When the adjustable negative capacitor 123 of the shunt circuit 120 is -52 nF, the sound absorption coefficient of the vibration absorption unit 100 reaches a peak value of 0.6 at a vibration signal frequency of 900 Hz, that is, the operating frequency of the vibration absorption unit 100 is 900 Hz at this time. When the adjustable negative capacitor 123 is -54 nF and -56 nF, the operating frequencies of the vibration absorption unit 100 are approximately 980 Hz and approximately 1030 Hz respectively. When the shunt circuit 120 is open-circuited and short-circuited, the operating frequencies are approximately 1120 Hz and approximately 1140 Hz respectively. From the characteristic that the operating frequency changes with the capacitance parameter, it can be obtained that the adjustable range of the resonance frequency in the embodiment of the present application is 20% of the initial resonance frequency.

[0054] Figure 7 This is the vibration absorption frequency following effect diagram provided by the present application. As Figure 7 shown, when the shunt circuit 120 is working, the resonance frequency of the vibration absorber 110 in the present application always changes above and below the excitation frequency. That is, when the resonance frequency is greater than or less than the excitation frequency, under the control of the vibration absorption frequency movement algorithm, the shunt circuit 120 always makes the resonance frequency move towards the direction close to the excitation frequency. When the operating frequency of the aircraft engine is adjusted, the excitation frequency changes, and the resonance frequency can approach the changed excitation frequency through multiple circuit parameter adjustments. For example, when the excitation frequency is reduced from 320 Hz to 270 Hz, the resonance frequency follows to near 270 Hz through multiple reductions of a fixed preset amplitude.

[0055] The embodiment of the present application also provides a structural noise suppression method, including: sensing the structural vibration signal through a piezoelectric element and generating a corresponding voltage signal; collecting the voltage signal; based on the change of the voltage signal, changing the resonance frequency of the vibration absorber 110 by adjusting the circuit parameters of the shunt circuit 120; the resonance frequency of the vibration absorber 110 matches the frequency of the vibration noise to absorb the vibration energy and suppress the structural noise.

[0056] Figure 8 This is the flowchart of the circuit parameter adjustment method provided by the present application. As Figure 8 shown, based on the change of the voltage signal, changing the resonance frequency of the vibration absorber 110 by adjusting the circuit parameters of the shunt circuit 120 is achieved through the following steps: S1: calculating the difference between the current voltage signal and the historical voltage signal; S2: determining the increment of the adjustable negative capacitor according to the difference sign, the increment sign of the historical adjustable negative capacitor, and the preset amplitude; S3: adjusting the resistance value of the adjustable resistor to change the amplification factor of the operational amplifier circuit, and then adjusting the value of the adjustable negative capacitor.

[0057] Reference Figure 7 With Figure 8 , when the frequency of the structural vibration signal changes, that is Figure 7 when the excitation frequency in changes, the circuit parameter adjustment method flow as shown in Figure 8 should be repeatedly executed to continuously collect the voltage signal and continuously adjust the parameters of the tunable negative capacitor 123, so as to realize that the resonance frequency of the vibration absorber 110 dynamically follows the change of the frequency of the structural vibration signal.

[0058] The introduction provided in the above steps is only used to help understand the method, structure and core idea of this application. For those of ordinary skill in the art, without departing from the principle of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of the claims of this application.

Claims

1. A structure-borne noise suppression system, characterized in that: include: An array of multiple independent vibration absorbing units that are attached to vibrating structures to suppress structure-borne noise; The vibration absorbing unit includes a vibration absorber and a shunt circuit; The vibration absorber includes at least one piezoelectric element for sensing vibration and outputting a voltage signal, and the shunt circuit is used to collect the voltage signal and adjust the shunt circuit parameters according to the voltage signal, thereby adjusting the resonant frequency of the vibration absorber; Wherein, when the shunt circuit is working, if the voltage signal increases, the current change trend of the circuit parameters is maintained; if the voltage signal decreases, the circuit parameters are adjusted to change in a direction opposite to the current change trend.

2. The structure-borne noise suppression system according to claim 1, characterized in that: The vibration absorber includes a stacked proton, a piezoelectric sheet, a substrate and a hard frame; The piezoelectric sheet is a piezoelectric element used to sense vibration and output a voltage signal through the piezoelectric effect, and the hard frame is used to fit with the vibration structure to transmit the vibration signal; The initial resonance frequency of the vibration absorber is determined by the proton mass.

3. The structure-borne noise suppression system according to claim 2, characterized in that: The substrate is made of a flexible film material, and the hard frame fixes the edge of the substrate and transmits a vibration signal.

4. The structure-borne noise suppression system according to claim 3, characterized in that: The hard frame is rigidly connected to the vibration structure.

5. The structure-borne noise suppression system according to claim 2, characterized in that: The mass of the proton is adjustable, and protons of different masses correspond to different initial resonance frequencies of the vibration absorber.

6. The structure-borne noise suppression system according to claim 2, characterized in that: The plurality of independent vibration absorbing units include at least two protons with different masses to expand the working frequency band of the array.

7. The structure-borne noise suppression system according to claim 2, characterized in that: In the plurality of independent vibration absorbing units, the protons of the vibration absorbers are arranged in an arithmetic increasing manner.

8. The structure-borne noise suppression system according to claim 1, characterized in that: The shunt circuit includes a signal collector, a controller and an adjustable negative capacitor; The signal collector is coupled to the piezoelectric element, and is used to collect the voltage signal and convert the voltage signal into a digital signal; The controller is used to receive the digital signal, and calculate the change amount of the adjustable negative capacitance according to the digital signal to output a control signal; The adjustable negative capacitor is connected in parallel with the piezoelectric element and is controlled by the controller to receive the control signal.

9. The structure-borne noise suppression system according to claim 8, characterized in that: The adjustable negative capacitor at least includes an adjustable resistor, a fixed resistor, an operational amplifier circuit and a fixed capacitor; The fixed capacitor, the adjustable resistor and the fixed resistor are connected in series and then connected to both ends of the piezoelectric element; The operational amplifier circuit is used to receive the voltage on the adjustable resistor and couple the amplification factor to the fixed capacitor; The controller changes the amplification factor of the operational amplifier circuit by adjusting the resistance value of the adjustable resistor, thereby changing the value of the adjustable negative capacitor.

10. The structure-borne noise suppression system according to claim 8, characterized in that: The shunt circuit uses a vibration absorption frequency shift algorithm to adjust the resonance frequency of the vibration absorber; The vibration absorption frequency shift algorithm is characterized in that the control signal output by the controller is a sequence signal with the same amplitude, and the sign of the n+1th control signal is determined by an AND operation logic, and the two operation elements of the AND operation logic are: the difference sign between the n+1th voltage signal and the nth voltage signal, and the sign of the nth control signal; Wherein, n is a natural number, and when n is 0, the sign of the control signal is preset to be positive.

11. The structure-borne noise suppression system according to claim 10, characterized in that: The adjustment increment of the adjustable negative capacitance is: ΔC n+1 =sgn(U n+1 -U n )·sgn(ΔC n )·K Where, ΔC n is the nth adjustment increment of the adjustable negative capacitance, U n is the nth voltage signal, sgn is the sign function, representing the sign of the variable in brackets, and K is the preset amplitude.

12. The structure-borne noise suppression system according to claim 11, characterized in that: The preset amplitude is converged and optimized through a PID algorithm to increase the adjustment speed of the resonance frequency of the vibration absorber.

13. A method for suppressing structure-borne noise, applied to a structure-borne noise suppression system, characterized in that: include: The piezoelectric element senses the structural vibration signal and generates a corresponding voltage signal; collecting the voltage signal; Based on the variation trend of the voltage signal, adjusting the circuit parameters of the shunt circuit to change the resonant frequency of the vibration absorber; The resonant frequency of the vibration absorber matches the frequency of the structural vibration signal to absorb vibration energy and suppress structure-borne noise.

14. The method for suppressing structure-borne noise according to claim 13, characterized in that: The changing of the resonant frequency of the vibration absorber by adjusting the circuit parameters of the shunt circuit based on the change of the voltage signal is achieved by the following steps: Calculate the difference between the current voltage signal and the historical voltage signal; Determining the increment of the adjustable negative capacitance according to the sign of the difference, the sign of the increment of the historical adjustable negative capacitance, and the preset amplitude; The resistance value of the adjustable resistor is adjusted to change the amplification factor of the operational amplifier circuit, thereby adjusting the value of the adjustable negative capacitance.

15. The method for suppressing structure-borne noise according to claim 13, characterized in that: When the frequency of the structural vibration signal changes, the voltage signal acquisition is repeatedly performed and the adjustable negative capacitance is continuously adjusted to enable the resonant frequency of the vibration absorber to dynamically follow the frequency change of the structural vibration signal.

16. The method for suppressing structure-borne noise according to claim 13, characterized in that: The adjustable range of the resonant frequency is 20% of the initial resonant frequency.

17. The method for suppressing structure-borne noise according to claim 13, characterized in that: The amplitude of the voltage signal is the product of the amplitude of the structural vibration signal and the response amplitude of the vibration absorber. When the vibration absorber resonates with the structural vibration signal, the voltage signal reaches a maximum value.

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