An omnidirectional pressure measurement system and method

Abstract

This invention relates to the field of pressure testing technology and discloses an omnidirectional pressure measurement system and method. The omnidirectional pressure measurement system includes a spherical piezoelectric sensor array module, a signal conditioning module, a signal storage and transmission module, and a host computer. The spherical piezoelectric sensor array module collects pressure signals in space, processes them through the signal conditioning module, and transmits them to the host computer via the storage and transmission module. The host computer calculates the pressure field intensity and pressure source location at each point and reconstructs the pressure field using the data. This invention employs a spherical array design with a dodecahedral vertex topology, enabling the system to achieve multi-angle information acquisition and depth perception, eliminating detection blind spots. This invention constructs a weighting function in a spherical coordinate system, calculates the pressure intensity at each point in space using a weighted average, estimates the initial position of the pressure source by squaring the measured value, and combines iterative algorithms for precise positioning. This invention not only improves measurement accuracy and efficiency but also enables the reconstruction of dynamic pressure fields.

Description

Technical Field

[0001] This invention relates to the field of pressure testing technology, and in particular to an omnidirectional pressure measurement system and method. Background Technology

[0002] Dynamic pressure field measurement is an important tool in scientific research and engineering applications, widely used in aerospace, automotive industry, explosion mechanics, acoustic analysis, and gas leak detection. Furthermore, information on the distribution, rate of change, and fluctuation characteristics of dynamic pressure fields can be applied to aircraft design optimization, explosion yield assessment, noise control, and gas equipment inspection.

[0003] Traditional pressure field measuring instruments typically employ single-point sensors or a limited array of sensors. While capable of measuring pressure at specific locations or localized areas, existing measurement systems suffer from limitations in measurement range and inability to comprehensively reflect the spatial pressure field distribution. Furthermore, they exhibit insufficient measurement accuracy and poor real-time performance. Particularly when facing complex and dynamically changing scenarios such as sound field propagation and explosion shock wave propagation, current technologies often struggle to capture all crucial information, leading to deviations or omissions in measurement results. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an omnidirectional pressure measurement system and method, which is based on a spherical array structure with a dodecahedral vertex topology. By constructing a weight function in the spherical coordinate system and using weighted averaging combined with iterative algorithms for calculation and optimization, it can effectively solve the problems of limited measurement range, detection blind zone, insufficient accuracy and poor real-time performance of traditional pressure field measuring instruments, and realize high-precision, omnidirectional and deep sensing and reconstruction of spatial dynamic pressure fields.

[0005] To achieve the aforementioned objectives, the technical solution adopted is as follows:

[0006] An omnidirectional pressure measurement system includes a spherical piezoelectric sensor array module, a signal conditioning module, a signal storage and transmission module, and a host computer;

[0007] The spherical piezoelectric sensor array module includes 19 piezoelectric sensors. Each piezoelectric sensor includes a piezoelectric sensor probe composed of a hemispherical piezoelectric element, with its surface facing the object being measured. When an external force is applied to the probe, the piezoelectric element deforms, causing a charge to be generated on its surface. Each piezoelectric sensor enters the signal conditioning module through an independent signal conditioning channel. The 19 piezoelectric sensors are embedded in a spherical shell with topological symmetry at the vertices of a regular dodecahedron to form a spherical array. By uniformly distributing them around a central point, the normal of the hemispherical piezoelectric sensor probe is strictly pointed to the outward direction of the vertex, forming a seamless detection domain on the spherical surface. By adjusting the mathematical model parameters according to actual needs, omnidirectional and accurate detection of dynamic pressure waves can be achieved.

[0008] The signal conditioning module includes a filter circuit, an integrated amplifier circuit, an isolation circuit, an analog-to-digital converter module, and a protection circuit, which are used to filter, amplify, isolate, and perform analog-to-digital conversion on the weak charge signal output by the piezoelectric sensor.

[0009] The signal storage and transmission module includes a storage module and a transmission module. The storage module stores the digital signal processed by the signal conditioning module, and the transmission module transmits the stored data to the host computer.

[0010] The host computer includes a calculation module for receiving digital signals and performing further algorithm optimization on the digital signals, and a display module. The display module displays the magnitude of the measured pressure field intensity and the location of the pressure source in real time, and also displays the reconstructed spatial pressure field in real time.

[0011] As a further improvement of the present invention, the piezoelectric sensor probe adopts a four-wire connection method, and uses the ratio method to eliminate lead wire errors and improve measurement accuracy. The four wires are two positive and negative leads and two signal lines. The positive and negative leads connect the piezoelectric element to the power supply, and the signal lines are connected to the signal conditioning module.

[0012] As a further improvement of the present invention, in response to the multi-frequency noise that sensor signals may carry in complex measurement environments, the filtering circuit is used to accurately filter out interference in specific frequency bands and improve signal quality; the integrated amplifier circuit amplifies and converts the weak electrical signal generated by the sensor under the action of pressure waves into a voltage signal; laying a solid foundation for subsequent optimization; since the sensors are widely distributed and numerous, the isolation circuit is used to prevent loop interference and signal crosstalk; to ensure the purity of signal transmission, the analog-to-digital conversion module is used to convert the above-processed voltage signal into a digital signal; the protection circuit is used to prevent circuit damage caused by sensor failure or external interference.

[0013] As a further improvement of the present invention, the spherical array is a dodecahedral vertex topology structure with densely arranged sensors at the top and no sensors at the bottom for device fixation. When the omnidirectional pressure measurement system is placed in the test platform, it can measure the magnitude of the pressure intensity of the dynamic field in space at different locations at the same time, and display the magnitude of the measured pressure field intensity and the location of the pressure source in real time. At the same time, it displays the reconstructed spatial pressure field.

[0014] As a further improvement of the present invention, the piezoelectric sensor probe is strictly aligned with the extended vertex of the dodecahedron in the normal direction, establishing a precise parameter mapping relationship between the array topological coordinate system and the spherical coordinate system. This ensures that the orientation parameters of each piezoelectric sensor accurately correspond to the direction of the symmetry axis of the face center of the dodecahedron pentagon. The geometric features of the dodecahedron are integrated into the construction of the weight function, optimizing the algorithm process and reducing computational redundancy. This greatly improves the measurement efficiency and real-time performance of the system while achieving high-precision measurement.

[0015] An omnidirectional pressure measurement method includes the following steps:

[0016] S1: The omnidirectional pressure measurement system is fixedly installed on the test platform, and a pressure source is arranged in the experimental site. The pressure source is activated, and a pressure wave is generated. The spherical piezoelectric sensor array module comes into contact with the pressure wave. Based on the piezoelectric effect, the piezoelectric element inside the sensor deforms and generates an electric charge signal.

[0017] S2: Due to the relatively low intensity of the pressure field, the charge signal measured by the spherical piezoelectric sensor array module is weak and contains noise. In order to meet the subsequent processing requirements, the charge signal is filtered and amplified in the signal conditioning module and converted into a voltage signal. Then, the amplified voltage signal is converted into a digital signal through the analog-to-digital converter module.

[0018] The spherical piezoelectric sensor array module measures the pressure field in space based on the piezoelectric effect to obtain the output voltage. Under ideal conditions, the magnitude of the pressure intensity experienced by the piezoelectric sensor is:

[0019]

[0020] In the formula, U i Let be the voltage value output by piezoelectric sensor i, d be the voltage coefficient of the piezoelectric sensor, S be the effective area of ​​the diaphragm, A0 be the amplification factor, and C be the voltage coefficient of the piezoelectric sensor. a For the capacitor in the amplifier circuit, C f For feedback capacitor;

[0021] S3: Signal storage and transmission module, which stores the digital signal processed by the signal conditioning module and transmits the stored data to the host computer through the transmission module;

[0022] S4: The host computer calculates the pressure intensity and pressure source location at each point in space by receiving the pressure field data, and reconstructs the pressure field using the data. Then, the measured pressure field intensity and pressure source location are displayed through the display module. At the same time, the reconstructed spatial pressure field is also displayed.

[0023] As a further improvement of the present invention, in step S4, the calculation of the pressure intensity at each point in space and the location of the pressure source is as follows:

[0024] The sphere of the spherical piezoelectric sensor array module has a radius of R. In the spherical coordinate system with the center of the sphere as the origin, the position coordinates r of piezoelectric sensor i are... i For (R,θ) i ,φ i The coordinates of the target point r are (p, θ, φ), where p is the distance from the target point to the center of the sphere, θ is the angle between the target point and the positive z-axis, and φ is the angle between the target point and the positive x-axis. The magnitude of the pressure intensity P at any target point in space is:

[0025]

[0026] Where, ω i Here, α is the weighting function, β is the dielectric attenuation coefficient, and α is the weighting function. i Let φ be the angle between the normal direction of the piezoelectric sensor i and the direction of the target point. i The difference in azimuth between the piezoelectric sensor and the target point;

[0027] By comparing the data measured by the piezoelectric sensor, the initial position of the pressure source is estimated. Then, by combining the iterative algorithm to continuously update the position and pressure intensity of the pressure source, the position of the pressure source can be accurately determined when the position change is less than the sphere radius R and the pressure change rate is less than 5%. The pressure source position is r1, and the pressure intensity is P1.

[0028]

[0029] Where, ||r s -r i ‖ represents the Euclidean distance between the pressure source and the piezoelectric sensor i, r s (k+1) The estimated location coordinates of the pressure source after the (k+1)th iteration.

[0030] The beneficial effects of this invention are as follows: This invention provides an omnidirectional pressure measurement system and method, which, combined with a spherical piezoelectric sensor array and hardware circuitry for signal conditioning, signal storage, and transmission, can measure dynamic pressure in space. This invention integrates 19 piezoelectric sensors in an array topologically distributed as the vertices of a regular dodecahedron onto a spherical shell. The sensor probes are precisely aligned with the outer vertices of the dodecahedron along their normal directions, enabling the system to achieve multi-angle information acquisition and depth sensing, eliminating blind spots, and allowing for adjustment of the sensor layout to optimize data as needed. This invention establishes a precise parameter mapping relationship between the array topological coordinate system and the spherical coordinate system. By incorporating the geometric features of the dodecahedron into the spherical coordinate system to construct a weighting function, a weighted average is used to calculate the pressure intensity at any point in space. The square of the sensor measurements is used as the weight to estimate the initial position of the pressure source, and an iterative algorithm is used to continuously update the position and pressure intensity of the pressure source to achieve precise positioning. This method reduces computational redundancy, greatly improving both measurement efficiency and real-time performance while achieving high-precision measurement. Attached Figure Description

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of an omnidirectional pressure measurement system according to the present invention;

[0033] Figure 2 This is a flowchart of an omnidirectional pressure measurement system;

[0034] Figure 3 This is a distribution diagram of the piezoelectric sensor of the present invention;

[0035] Figure 4 This is a schematic diagram of the system connection of the present invention. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0038] An omnidirectional pressure measurement system, such as Figure 1 As shown, it includes a spherical piezoelectric sensor array module, a signal conditioning module, a signal storage and transmission module, and a host computer;

[0039] The spherical piezoelectric sensor array module includes 19 piezoelectric sensors. Each piezoelectric sensor includes a piezoelectric sensor probe composed of a hemispherical piezoelectric element, with its surface facing the object being measured. When an external force is applied to the probe, the piezoelectric element deforms, causing a charge to be generated on its surface. Each piezoelectric sensor enters the signal conditioning module through an independent signal conditioning channel. The 19 piezoelectric sensors are embedded in a spherical shell with topological symmetry at the vertices of a regular dodecahedron to form a spherical array. By uniformly distributing them around a central point, the normal of the hemispherical piezoelectric sensor probe is strictly pointed to the outward direction of the vertex, forming a seamless detection domain on the spherical surface. By adjusting the mathematical model parameters according to actual needs, omnidirectional and accurate detection of dynamic pressure waves can be achieved.

[0040] The signal conditioning module includes a filter circuit, an integrated amplifier circuit, an isolation circuit, an analog-to-digital converter module, and a protection circuit, which are used to filter, amplify, isolate, and perform analog-to-digital conversion on the weak charge signal output by the piezoelectric sensor.

[0041] The signal storage and transmission module includes a storage module and a transmission module. The storage module stores the digital signal processed by the signal conditioning module, and the transmission module transmits the stored data to the host computer.

[0042] The host computer includes a calculation module for receiving digital signals and performing further algorithm optimization on the digital signals, and a display module. The display module displays the magnitude of the measured pressure field intensity and the location of the pressure source in real time, and also displays the reconstructed spatial pressure field in real time.

[0043] The piezoelectric sensor probe adopts a four-wire connection method, using a ratio method to eliminate lead wire errors and improve measurement accuracy. The four wires are two positive and negative leads and two signal lines. The positive and negative leads connect the piezoelectric element to the power supply, and the signal lines are connected to the signal conditioning module.

[0044] To address the multi-frequency noise that sensor signals may carry in complex measurement environments, the filtering circuit is used to accurately filter out interference in specific frequency bands, improving signal quality. The integrated amplifier circuit amplifies and converts the weak electrical signal generated by the sensor under the action of pressure waves into a voltage signal, laying a solid foundation for subsequent optimization. Due to the wide distribution and large number of sensors, the isolation circuit is used to prevent loop interference and signal crosstalk. To ensure the purity of signal transmission, the analog-to-digital converter module is used to convert the processed voltage signal into a digital signal. The protection circuit is used to prevent circuit damage caused by sensor failure or external interference.

[0045] like Figure 3 As shown, the piezoelectric sensor probes are topologically symmetrically distributed on the spherical shell with the vertices of a regular dodecahedron. The system is a spherical shell structure, as... Figure 4 As shown, the omnidirectional pressure measurement system is placed in the test platform and can measure the magnitude of the pressure intensity of the dynamic field in space at different locations at the same time. It can also display the magnitude of the measured pressure field intensity and the location of the pressure source in real time, as well as the reconstructed spatial pressure field.

[0046] The piezoelectric sensor probe is precisely aligned with the extended vertex of the dodecahedron in the normal direction, establishing a precise parameter mapping relationship between the array topological coordinate system and the spherical coordinate system. This ensures that the orientation parameters of each piezoelectric sensor accurately correspond to the direction of the symmetry axis of the face center of the dodecahedron pentagon. The geometric features of the dodecahedron are integrated into the construction of the weight function, optimizing the algorithm process and reducing computational redundancy. As a result, the system achieves high-precision measurement while greatly improving measurement efficiency and real-time performance.

[0047] An omnidirectional pressure measurement method, such as Figure 2 As shown, it includes the following steps:

[0048] S1: The omnidirectional pressure measurement system is fixedly installed on the test platform, and a pressure source is arranged in the experimental site. The pressure source is activated, and a pressure wave is generated. The spherical piezoelectric sensor array module comes into contact with the pressure wave. Based on the piezoelectric effect, the piezoelectric element inside the sensor deforms and generates an electric charge signal.

[0049] S2: Due to the relatively low intensity of the pressure field, the charge signal measured by the spherical piezoelectric sensor array module is weak and contains noise. In order to meet the subsequent processing requirements, the charge signal is filtered and amplified in the signal conditioning module and converted into a voltage signal. Then, the amplified voltage signal is converted into a digital signal through the analog-to-digital converter module.

[0050] The spherical piezoelectric sensor array module measures the pressure field in space based on the piezoelectric effect to obtain the output voltage. Under ideal conditions, the magnitude of the pressure intensity experienced by the piezoelectric sensor is:

[0051]

[0052] In the formula, U i Let be the voltage value output by piezoelectric sensor i, d be the voltage coefficient of the piezoelectric sensor, S be the effective area of ​​the diaphragm, A0 be the amplification factor, and C be the voltage coefficient of the piezoelectric sensor. a For the capacitor in the amplifier circuit, C f For feedback capacitor;

[0053] S3: Signal storage and transmission module, which stores the digital signal processed by the signal conditioning module and transmits the stored data to the host computer through the transmission module;

[0054] S4: The host computer calculates the pressure intensity and pressure source location at each point in space by receiving the pressure field data, and reconstructs the pressure field using the data. Then, the measured pressure field intensity and pressure source location are displayed through the display module. At the same time, the reconstructed spatial pressure field is also displayed.

[0055] In step S4, the magnitude of the pressure intensity at each point in space and the location of the pressure source are calculated as follows:

[0056] The sphere of the spherical piezoelectric sensor array module has a radius of R. In the spherical coordinate system with the center of the sphere as the origin, the position coordinates r of piezoelectric sensor i are... i For (R,θ) i ,φ i The coordinates of the target point r are (p, θ, φ), where p is the distance from the target point to the center of the sphere, θ is the angle between the target point and the positive z-axis, and φ is the angle between the target point and the positive x-axis. The magnitude of the pressure intensity P at any target point in space is:

[0057]

[0058] Where, ω i Here, α is the weighting function, β is the dielectric attenuation coefficient, and α is the weighting function. i Let φ be the angle between the normal direction of the piezoelectric sensor i and the direction of the target point. i The difference in azimuth between the piezoelectric sensor and the target point;

[0059] By comparing the data measured by the piezoelectric sensor, the initial position of the pressure source is estimated. Then, by combining the iterative algorithm to continuously update the position and pressure intensity of the pressure source, the position of the pressure source can be accurately determined when the position change is less than the sphere radius R and the pressure change rate is less than 5%. The pressure source position is r1, and the pressure intensity is P1.

[0060]

[0061] Where, ||r s -r i ‖ represents the Euclidean distance between the pressure source and the piezoelectric sensor i, r s (k+1) The estimated location coordinates of the pressure source after the (k+1)th iteration.

[0062] This invention utilizes a spherical array structure based on the vertex topology of a regular dodecahedron to achieve multi-angle information acquisition and depth sensing, allowing for on-demand optimization of sensor layout. By constructing a weighting function in a spherical coordinate system, the pressure intensity at any point in space is calculated using a weighted average. The initial position of the pressure source is estimated using the square of the sensor measurements as weights. Combined with an iterative algorithm, the position and pressure intensity of the pressure source are continuously updated. When the position change is less than the sphere radius R and the pressure change rate is less than 5%, the pressure source can be accurately located. The pressure field is then reconstructed using software, effectively solving the problems of limited measurement range of traditional single-point pressure sensors and the detection blind zone of planar array sensors, making it difficult to obtain high-precision pressure field distribution.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, component splitting or combination, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An omnidirectional pressure measurement system, characterized by: It comprises a spherical piezoelectric sensor array module, a signal conditioning module, a signal storage and transmission module, and an upper computer. The spherical piezoelectric sensor array module comprises 19 piezoelectric sensors, each of which comprises a piezoelectric sensor probe composed of a hemispherical piezoelectric element, the surface of which faces the measured object, when external force acts on the probe, the piezoelectric element will deform, resulting in electric charge on its surface, each piezoelectric sensor enters the signal conditioning module through an independent signal conditioning channel, and the 19 piezoelectric sensors are embedded on a spherical shell in a topological symmetry of a regular dodecahedron vertex to form a spherical array, which is uniformly distributed around a center point, so that the normal line of the hemispherical piezoelectric sensor probe is strictly directed to the extension direction of the vertex, forming a seamless detection domain on the spherical surface. The signal conditioning module comprises a filter circuit, an integrated amplification circuit, an isolation circuit, an analog-to-digital conversion module, and a protection circuit, which is used for filtering, amplifying, isolating, and analog-to-digital converting the weak charge signal output by the piezoelectric sensor. The signal storage and transmission module comprises a storage module and a transmission module, the storage module stores the digital signal processed by the signal conditioning module, and the transmission module transmits the stored data to the upper computer. The upper computer comprises a calculation module for receiving the digital signal and optimizing the algorithm of the digital signal, and a display module, which displays the measured pressure field intensity, the position of the pressure source, and the reconstructed spatial pressure field in real time. The piezoelectric sensor probe adopts a four-wire connection method, and the lead error is eliminated by using the ratio method to improve the measurement accuracy, the four wires are two positive and negative leads and two signal lines, the positive and negative leads connect the piezoelectric element and the power supply, and the signal lines are connected to the signal conditioning module.

2. The omni-directional pressure measurement system of claim 1, wherein: The filter circuit is used to accurately filter out interference in a specific frequency band and improve signal quality; the integrated amplification circuit amplifies the weak electric signal generated by the sensor under the action of the pressure wave and converts it into a voltage signal; the isolation circuit is used to prevent loop interference and signal crosstalk; the analog-to-digital conversion module is used to convert the voltage signal into a digital signal; and the protection circuit is used to prevent circuit damage caused by sensor failure or external interference.

3. The omni-directional pressure measurement system of claim 1, wherein: The omnidirectional pressure measurement system is placed in the test platform, which can measure the pressure intensity at different positions in the dynamic field at the same time, and display the measured pressure field intensity, the position of the pressure source, and the reconstructed spatial pressure field in real time.

4. The omni-directional pressure measurement system of claim 1, wherein: The piezoelectric sensor probe is strictly aligned with the normal direction of the extension vertex of the regular dodecahedron, establishing an accurate parameter mapping relationship between the array topological coordinate system and the spherical coordinate system, so that the orientation parameters of each piezoelectric sensor can accurately correspond to the direction of the regular dodecahedron pentagon face center symmetry axis, and the geometric characteristics of the regular dodecahedron are integrated into the construction of the weight function.

5. An omni-directional pressure measurement method using the omni-directional pressure measurement system of claim 1, characterized by, The method comprises the following steps: S1: Fix and install the omnidirectional pressure measurement system on the test platform, arrange the pressure source in the experimental site, activate the pressure source, and the pressure source generates pressure waves immediately, the spherical piezoelectric sensor array module contacts the pressure waves, and based on the piezoelectric effect, the piezoelectric element inside the sensor deforms to generate an electric charge signal; S2: Because the pressure field action intensity is relatively low, the charge signal measured by the spherical piezoelectric sensor array module is weak and has noise. In order to meet the subsequent processing requirements, the signal conditioning module is used to filter and amplify the charge signal, and the signal is converted into a voltage signal. Then, the amplified voltage signal is converted into a digital signal through an analog-to-digital conversion module; The spherical piezoelectric sensor array module measures the pressure field in space according to the piezoelectric effect principle to obtain an output voltage. In an ideal case, the pressure intensity received by the piezoelectric sensor is: ； wherein is the voltage coefficient of the piezoelectric sensor is the output voltage value, is the voltage coefficient of the piezoelectric sensor is the effective area of the diaphragm, is the amplification factor, is the amplification circuit capacitance, is the feedback capacitance; S3: The signal storage and transmission module stores the digital signal processed by the signal conditioning module, and transmits the stored data to the upper computer through the transmission module; S4: The upper computer calculates the pressure intensity of each point in space and the position of the pressure source through the received pressure field data, reconstructs the pressure field using the data, and displays the measured pressure field intensity, the position of the pressure source, and the reconstructed space pressure field through the display module.

6. The omni-directional pressure measurement method of claim 5, wherein, In step S4, the calculation of the pressure intensity of each point in space and the position of the pressure source is as follows: The radius of the sphere in the spherical piezoelectric sensor array module is In a spherical coordinate system with the center of the sphere as the origin, a piezoelectric sensor Position coordinates for Coordinates of the target point for ,in Let be the distance from the target point to the center of the ball. Let be the angle between the target point and the positive z-axis. The angle between the target point and the positive x-axis represents the magnitude of the pressure intensity at any target point in space. for: ； wherein, is a weight function, is a medium attenuation coefficient, is a piezoelectric sensor is an angle between a normal direction and a target point direction, is a difference between a piezoelectric sensor and a target point azimuth angle; The data measured by the piezoelectric sensor is compared, the initial position of the pressure source is estimated, and the iterative algorithm is combined to continuously update the position and pressure intensity of the pressure source. When the position change is less than the ball radius R and the pressure change rate is less than 5%, the position of the pressure source can be accurately determined , the pressure intensity of the pressure source : ； wherein, is the Euclidean distance between the pressure source and the piezoelectric sensor, the first k estimated position coordinates of the pressure source after the +1 iteration.​

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