Method and apparatus for modifying piezoelectric sensor response signals

Abstract

The application belongs to the technical field of aircraft strength test, and particularly relates to a piezoelectric sensor response signal correction method and device. The method comprises the following steps: S1, acquiring a first response signal of a first piezoelectric sensor and a second response signal of a second piezoelectric sensor after a first knock position on a symmetrical composite material structure is knocked, wherein the first knock position is symmetrically designed with the first piezoelectric sensor on the composite material structure; S2, acquiring a third response signal of the first piezoelectric sensor and a fourth response signal of the second piezoelectric sensor after a second knock position on the symmetrical composite material structure is knocked, wherein the second knock position is symmetrically designed with the second piezoelectric sensor on the composite material structure; S3, calculating a correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor; and S4, correcting the response signal of the piezoelectric sensor. The application improves the uniformity of the response signals of the piezoelectric sensors.

Description

Technical Field

[0001] This application belongs to the field of aircraft strength testing technology, and specifically relates to a method and apparatus for correcting the response signal of a piezoelectric sensor. Background Technology

[0002] Piezoelectric sensors and their networks are an important prerequisite for conducting piezoelectric sensor-based structural health monitoring. Piezoelectric sensor correction is an important foundation for aircraft strength testing, and the consistency of sensors directly affects the accuracy and reliability of experimental results.

[0003] When implementing piezoelectric-based structural health monitoring technology for aerospace structures, environmental changes, structural loads, and adhesive aging can affect the guided wave signals monitored by piezoelectric sensors, thus impacting subsequent structural damage assessment. Therefore, it is necessary to correct the response signals of piezoelectric sensors. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a method and apparatus for correcting the response signal of a piezoelectric sensor, applicable to systems in which at least two piezoelectric sensors are positioned outside the transverse or longitudinal axis of symmetry of a symmetrical composite material.

[0005] The first aspect of this application provides a method for correcting the response signal of a piezoelectric sensor, mainly including:

[0006] Step S1: Obtain the first response signal of the first piezoelectric sensor and the second response signal of the second piezoelectric sensor after being struck at the first striking position on the symmetrical composite material structure, wherein the first striking position and the first piezoelectric sensor are designed symmetrically on the composite material structure.

[0007] Step S2: Obtain the third response signal of the first piezoelectric sensor and the fourth response signal of the second piezoelectric sensor after being struck at the second striking position on the symmetrical composite material structure, wherein the second striking position and the second piezoelectric sensor are designed symmetrically on the composite material structure.

[0008] Step S3: Calculate the correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor based on the first response signal, the second response signal, the third response signal and the fourth response signal;

[0009] Step S4: Using the response signal of one of the first and second piezoelectric sensors as a reference, correct the response signal of the other piezoelectric sensor according to the correction coefficient.

[0010] Preferably, in step S3, the correction coefficient a is calculated using the following formula:

[0011]

[0012] Among them, E F1J1 E is the time-domain integral of the first response signal. F1J2 E is the time-domain integral of the third response signal. F2J1 E is the time-domain integral of the second response signal. F2J2 This is the time-domain integral of the fourth response signal.

[0013] Preferably, step S3 further includes:

[0014] Each test is defined as striking once at the first striking position and once at the second striking position. A corresponding correction coefficient is calculated, and the average of the multiple correction coefficients obtained from multiple tests is taken as the final correction coefficient.

[0015] Preferably, step S3 further includes:

[0016] For a piezoelectric sensor network consisting of multiple piezoelectric sensors, all are based on the same piezoelectric sensor. The reference piezoelectric sensor is used to form a symmetrical position for a tapping experiment with other piezoelectric sensors to obtain the corresponding correction coefficient.

[0017] Preferably, one piezoelectric sensor with a smooth response signal waveform is selected from among multiple piezoelectric sensors as the reference piezoelectric sensor.

[0018] A second aspect of this application provides a device for correcting the response signal of a piezoelectric sensor, mainly comprising:

[0019] The module for acquiring response signals after a first impact position is used to acquire the first response signal of the first piezoelectric sensor and the second response signal of the second piezoelectric sensor after an impact at the first impact position on the symmetrical composite material structure, wherein the first impact position and the first piezoelectric sensor are designed symmetrically on the composite material structure.

[0020] The response signal acquisition module after the second striking position is used to acquire the third response signal of the first piezoelectric sensor and the fourth response signal of the second piezoelectric sensor after the second striking position is struck on the symmetrical composite material structure, wherein the second striking position and the second piezoelectric sensor are designed symmetrically on the composite material structure.

[0021] The correction coefficient calculation module is used to calculate the correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor based on the first response signal, the second response signal, the third response signal and the fourth response signal;

[0022] The piezoelectric sensor correction module is used to correct the response signal of the other piezoelectric sensor based on the response signal of one of the first and second piezoelectric sensors, according to the correction coefficient.

[0023] Preferably, in the correction coefficient calculation module, the correction coefficient a is calculated using the following formula:

[0024]

[0025] Among them, E F1J1 E is the time-domain integral of the first response signal. F1J2 E is the time-domain integral of the third response signal. F2J1 E is the time-domain integral of the second response signal. F2J2 This is the time-domain integral of the fourth response signal.

[0026] Preferably, the correction coefficient calculation module further includes:

[0027] The mean calculation unit is used to calculate a corresponding correction coefficient by taking one strike at each of the first and second strike positions as one test, and to take the average of the multiple correction coefficients obtained from multiple tests as the final correction coefficient.

[0028] Preferably, the correction coefficient calculation module further includes:

[0029] The reference selection unit is used to select a piezoelectric sensor network composed of multiple piezoelectric sensors, and to select the same piezoelectric sensor as the reference. The reference piezoelectric sensor is then used to form a symmetrical position for a tapping experiment with other piezoelectric sensors to obtain the corresponding correction coefficient.

[0030] Preferably, one piezoelectric sensor with a smooth response signal waveform is selected from among multiple piezoelectric sensors as the reference piezoelectric sensor.

[0031] This application improves the uniformity of the response signals of each piezoelectric sensor and enhances the accuracy of impact identification. Attached Figure Description

[0032] Figure 1 This is a flowchart of a preferred embodiment of the method for correcting the piezoelectric sensor response signal of this application.

[0033] Figure 2 This is a schematic diagram of the arrangement of piezoelectric sensors on a symmetrical composite material structure.

[0034] Figure 3 This is a schematic diagram of the impact location on a composite material structure.

[0035] Figure 4This is a schematic diagram illustrating the effect of the piezoelectric sensor response signal correction method according to this application. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0037] The first aspect of this application provides a method for correcting the response signal of a piezoelectric sensor, such as... Figure 1 As shown, it mainly includes:

[0038] Step S1: Obtain the first response signal of the first piezoelectric sensor and the second response signal of the second piezoelectric sensor after being struck at the first striking position on the symmetrical composite material structure, wherein the first striking position and the first piezoelectric sensor are designed symmetrically on the composite material structure.

[0039] Step S2: Obtain the third response signal of the first piezoelectric sensor and the fourth response signal of the second piezoelectric sensor after being struck at the second striking position on the symmetrical composite material structure, wherein the second striking position and the second piezoelectric sensor are designed symmetrically on the composite material structure.

[0040] Step S3: Calculate the correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor based on the first response signal, the second response signal, the third response signal and the fourth response signal;

[0041] Step S4: Using the response signal of one of the first and second piezoelectric sensors as a reference, correct the response signal of the other piezoelectric sensor according to the correction coefficient.

[0042] The principle of the correction method in this application is to obtain the corrected response signal by taking the response signal of one sensor as a reference and multiplying the original response signal of the other sensor to be corrected by a correction coefficient. The corrected response signal can maintain consistency with the reference sensor.

[0043] like Figure 2As shown, two piezoelectric sensors first need to be arranged on a symmetrical composite material structure 100, which is symmetrical about the longitudinal axis 110 or about the transverse axis 120. It is understandable that when the two piezoelectric sensors are symmetrical about the axis of symmetry, it is only necessary to tap at their center point, and the signal of the piezoelectric sensors can be corrected by ensuring that the integrals of the response signals in the time domain are equal. However, in actual working conditions, the arrangement of piezoelectric sensors is usually complex, which leads to… Figure 2 The piezoelectric sensor layout shown is such that the first piezoelectric sensor J1 and the second piezoelectric sensor J2 are not symmetrical along the vertical axis 110 or the horizontal axis 120. In this case, it can be arranged according to... Figure 3 The embodiments shown define a first striking position F1 and a second striking position F2 respectively. In this embodiment, it is assumed that the axis of symmetry of the symmetrical composite material structure 100 is the horizontal axis 120. Then, the first striking position F1 is symmetrical with the first piezoelectric sensor J1 on the horizontal axis 120, and the second striking position F2 is symmetrical with the second piezoelectric sensor J2 on the horizontal axis 120.

[0044] Then, the first and second impacts are performed sequentially to obtain the response signals of each piezoelectric sensor. The signals are then integrated in the time domain. Based on the principle of linear relationship between impact force and piezoelectric sensor signal, if impact force F1 and F2 act on the same point and the waveforms of impact force F1 and F2 are similar but different in amplitude, then the ratio of impact force signals is equal to the ratio of sensor signals.

[0045] In this embodiment, the second piezoelectric sensor J2 is selected as the standard sensor, and the first piezoelectric sensor J1 is assumed to be the sensor to be corrected, with a correction coefficient of a. Figure 3 As shown, the integral of the first response signal of the first pressure sensor after impact with impact force F1 in the time domain is E. F1J1 The integral of the second response signal of the second pressure sensor in the time domain is E F2J1 The integral of the third response signal of the first pressure sensor after impact with impact force F2 in the time domain is E. F1J2 The integral of the fourth response signal of the second pressure sensor in the time domain is E F2J2 These parameters and the correction coefficient a satisfy the following relationship:

[0046] in This represents the ratio of the second impact force to the signal of the first impact force. Transforming the above formula yields the correction coefficient 'a':

[0047]

[0048] Once the correction coefficient 'a' is determined, the original response signal of the first piezoelectric sensor can be corrected based on the response signal of the second piezoelectric sensor to any impact on the asymmetric composite material structure, using the response signal of the second piezoelectric sensor as the standard response signal.

[0049] like Figure 4 As shown, the original response signal of the first piezoelectric sensor, i.e. the signal to be corrected S1 in the figure, is significantly different from the standard response signal S2 of the second piezoelectric sensor. However, after correction by the correction coefficient a, the corrected response signal S3 of the first piezoelectric sensor has a better match with the standard response signal S2 of the second piezoelectric sensor. This proves that the correction improves the uniformity of the response signals of the two piezoelectric sensors and further improves the accuracy of impact identification.

[0050] In some alternative implementations, step S3 further includes:

[0051] Each test is defined as striking once at the first striking position and once at the second striking position. A corresponding correction coefficient is calculated, and the average of the multiple correction coefficients obtained from multiple tests is taken as the final correction coefficient.

[0052] This embodiment can increase the reliability of the test results by conducting multiple tests and taking an average value.

[0053] In some alternative implementations, step S3 further includes:

[0054] For a piezoelectric sensor network consisting of multiple piezoelectric sensors, all are based on the same piezoelectric sensor. The reference piezoelectric sensor is used to form a symmetrical position for a tapping experiment with other piezoelectric sensors to obtain the corresponding correction coefficient.

[0055] This embodiment is used in a network system consisting of multiple piezoelectric sensors. Based on the same reference, different correction coefficients of other piezoelectric sensors relative to the reference are calculated, thereby making the response signals of each piezoelectric sensor in the entire network system uniform.

[0056] In an alternative embodiment, multiple reference piezoelectric sensors can be selected and form a closed loop with each other. The correction coefficients are also corrected using this closed-loop method, thereby ensuring uniformity across the entire network system. For example, for a piezoelectric sensor network including a first piezoelectric sensor J1, a second piezoelectric sensor J2, a third piezoelectric sensor J3, and a fourth piezoelectric sensor J4, the first correction coefficient a1 of the first piezoelectric sensor J1 and the second piezoelectric sensor J2 can be determined by tapping the asymmetrical positions of the first piezoelectric sensor J1 and the second piezoelectric sensor J2; the second correction coefficient a2 of the second piezoelectric sensor J2 and the third piezoelectric sensor J3 can be determined by tapping the asymmetrical positions of the third piezoelectric sensor J3 and the fourth piezoelectric sensor J4. The tapping at the asymmetrical position of J4 determines the third correction coefficient a3 of the third piezoelectric sensor J3 and the fourth piezoelectric sensor J4; the tapping at the asymmetrical position of the fourth piezoelectric sensor J4 and the first piezoelectric sensor J1 determines the fourth correction coefficient a4 of the fourth piezoelectric sensor J4 and the first piezoelectric sensor J1. It can be understood that the product of the four correction coefficients calculated in the above embodiment is theoretically 1. Based on this, the four correction coefficients actually obtained can be fine-tuned to ensure consistency with the theory. In this way, it can be ensured that the four piezoelectric sensors of the entire network system can correct each other and have consistency.

[0057] In some alternative implementations, one piezoelectric sensor with a smooth response signal waveform among a plurality of piezoelectric sensors is selected as the reference piezoelectric sensor.

[0058] This embodiment is used to improve the accuracy of signal correction. In an alternative embodiment, two piezoelectric sensors can also be set under essentially the same conditions for signal correction, which can also improve the accuracy of signal correction.

[0059] A second aspect of this application provides a device for correcting the response signal of a piezoelectric sensor corresponding to the above method, mainly comprising:

[0060] The module for acquiring response signals after a first impact position is used to acquire the first response signal of the first piezoelectric sensor and the second response signal of the second piezoelectric sensor after an impact at the first impact position on the symmetrical composite material structure, wherein the first impact position and the first piezoelectric sensor are designed symmetrically on the composite material structure.

[0061] The response signal acquisition module after the second striking position is used to acquire the third response signal of the first piezoelectric sensor and the fourth response signal of the second piezoelectric sensor after the second striking position is struck on the symmetrical composite material structure, wherein the second striking position and the second piezoelectric sensor are designed symmetrically on the composite material structure.

[0062] The correction coefficient calculation module is used to calculate the correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor based on the first response signal, the second response signal, the third response signal and the fourth response signal;

[0063] The piezoelectric sensor correction module is used to correct the response signal of the other piezoelectric sensor based on the response signal of one of the first and second piezoelectric sensors, according to the correction coefficient.

[0064] In some optional embodiments, the correction coefficient a is calculated in the correction coefficient calculation module using the following formula:

[0065]

[0066] Among them, E F1J1 E is the time-domain integral of the first response signal. F1J2 E is the time-domain integral of the third response signal. F2J1 E is the time-domain integral of the second response signal. F2J2 This is the time-domain integral of the fourth response signal.

[0067] In some optional implementations, the correction coefficient calculation module further includes:

[0068] The mean calculation unit is used to calculate a corresponding correction coefficient by taking one strike at each of the first and second strike positions as one test, and to take the average of the multiple correction coefficients obtained from multiple tests as the final correction coefficient.

[0069] In some optional implementations, the correction coefficient calculation module further includes:

[0070] The reference selection unit is used to select a piezoelectric sensor network composed of multiple piezoelectric sensors, and to select the same piezoelectric sensor as the reference. The reference piezoelectric sensor is then used to form a symmetrical position for a tapping experiment with other piezoelectric sensors to obtain the corresponding correction coefficient.

[0071] In some alternative implementations, one piezoelectric sensor with a smooth response signal waveform among a plurality of piezoelectric sensors is selected as the reference piezoelectric sensor.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for correcting the response signal of a piezoelectric sensor, characterized in that, include: Step S1: Obtain the first response signal of the first piezoelectric sensor and the second response signal of the second piezoelectric sensor after being struck at the first striking position on the symmetrical composite material structure, wherein the first striking position and the first piezoelectric sensor are designed symmetrically on the composite material structure. Step S2: Obtain the third response signal of the first piezoelectric sensor and the fourth response signal of the second piezoelectric sensor after being struck at the second striking position on the symmetrical composite material structure, wherein the second striking position and the second piezoelectric sensor are designed symmetrically on the composite material structure. Step S3: Calculate the correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor based on the first response signal, the second response signal, the third response signal and the fourth response signal; Step S4: Using the response signal of one of the piezoelectric sensors, the first and second piezoelectric sensors, as a reference, the response signal of the other piezoelectric sensor is corrected according to the correction coefficient. In step S3, the correction factor is calculated using the following formula. : ； in, The time-domain integral of the first response signal, The time-domain integral of the third response signal, The time-domain integral of the second response signal, The time-domain integral of the fourth response signal; Step S3 further includes: One test is defined as striking once at the first striking position and once at the second striking position. A corresponding correction coefficient is calculated, and the average of the multiple correction coefficients obtained from multiple tests is taken as the final correction coefficient. For a piezoelectric sensor network consisting of multiple piezoelectric sensors, all are based on the same piezoelectric sensor. The reference piezoelectric sensor is used to form a symmetrical position for a tapping experiment with other piezoelectric sensors to obtain the corresponding correction coefficient.

2. The method for correcting the response signal of a piezoelectric sensor as described in claim 1, characterized in that, One piezoelectric sensor with a smooth response signal waveform is selected from among multiple piezoelectric sensors as the reference piezoelectric sensor.

3. A device for correcting the response signal of a piezoelectric sensor, characterized in that, include: The module for acquiring response signals after a first impact position is used to acquire the first response signal of the first piezoelectric sensor and the second response signal of the second piezoelectric sensor after an impact at the first impact position on the symmetrical composite material structure, wherein the first impact position and the first piezoelectric sensor are designed symmetrically on the composite material structure. The response signal acquisition module after the second striking position is used to acquire the third response signal of the first piezoelectric sensor and the fourth response signal of the second piezoelectric sensor after the second striking position is struck on the symmetrical composite material structure, wherein the second striking position and the second piezoelectric sensor are designed symmetrically on the composite material structure. The correction coefficient calculation module is used to calculate the correction coefficient between the first piezoelectric sensor and the second piezoelectric sensor based on the first response signal, the second response signal, the third response signal and the fourth response signal; A piezoelectric sensor correction module is used to correct the response signal of the other piezoelectric sensor based on the response signal of one of the first and second piezoelectric sensors, according to the correction coefficient. In the correction factor calculation module, the correction factor is calculated using the following formula. : ； in, The time-domain integral of the first response signal, The time-domain integral of the third response signal, The time-domain integral of the second response signal, The time-domain integral of the fourth response signal; The correction coefficient calculation module further includes: The mean calculation unit is used to calculate a corresponding correction coefficient by taking one strike at each of the first and second strike positions as one test, and to take the average of the multiple correction coefficients obtained from multiple tests as the final correction coefficient. The reference selection unit is used to select a piezoelectric sensor network composed of multiple piezoelectric sensors, and to select the same piezoelectric sensor as the reference. The reference piezoelectric sensor is then used to form a symmetrical position for a tapping experiment with other piezoelectric sensors to obtain the corresponding correction coefficient.

4. The device for correcting the piezoelectric sensor response signal as described in claim 3, characterized in that, One piezoelectric sensor with a smooth response signal waveform is selected from among multiple piezoelectric sensors as the reference piezoelectric sensor.

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