Tunable optical fiber vibration sensor device, system and method

Abstract

The invention relates to a tunable optical fiber vibration sensor device, system and method, and the device comprises a first optical fiber vibration sensor which comprises an elastic sheet, a sliding block, an adjusting part, a mass block, a pedestal, and an optical fiber; the elastic piece is in an isosceles trapezoid shape, and the thickness and the width of the elastic piece linearly change in the length direction of the elastic piece in the same trend, so that the two ends of the elastic piece in the length direction are a wide-thick end and a narrow-thin end respectively. The wide and thick ends of the elastic sheets are connected with the mass block, and the narrow and thin ends are connected with the base; the elastic piece is provided with a sliding connection part in sliding fit with the sliding block, and the sliding block can move in the length direction of the elastic piece. The adjusting piece is used for fixing the sliding block and the elastic piece. The optical fiber is provided with a coupling point connected with the base and the mass block, and the coupling point connected with the mass block can synchronously vibrate along with the mass block. Or the device comprises a second optical fiber vibration sensor, the wide and thick end of the elastic sheet is connected with the base, and the narrow and thin end is connected with the mass block. According to the invention, the use requirements of large response frequency bandwidth or / and sensitivity range can be met.

Description

Technical Field

[0001] This invention relates to the field of vibration sensor technology, and in particular to a tunable fiber optic vibration sensor device, system, and method. Background Technology

[0002] Rotary reciprocating electromechanical equipment, as a core power or transmission device, often causes system shutdown, damage, and even significant economic losses and endangers public safety if it malfunctions. Therefore, fault monitoring of electromechanical equipment is necessary to prevent safety accidents. Stress wave monitoring can detect early-stage faults at higher frequencies; however, stress waves attenuate rapidly when crossing interfaces and are easily affected by external environmental interference, leading to reduced fault diagnosis accuracy. Temperature sensors detect abnormal temperatures in electromechanical equipment only when the fault has entered a late stage, indicating irreversible damage. Therefore, compared to traditional monitoring technologies, vibration monitoring technology is relatively mature and can diagnose early-stage faults. Its monitoring range covers the entire unit's transmission chain, making it the most comprehensive and effective method for detecting faults in rotary reciprocating electromechanical equipment.

[0003] Fiber optic vibration sensors are high-precision monitoring devices based on fiber optic sensing technology. They sense external vibration information by detecting changes in the properties of light within the fiber. Cantilever beam fiber optic vibration sensors are vibration monitoring devices that combine a cantilever beam mechanical structure with fiber optic sensing technology. Their core principle is to utilize the mechanical deformation of the cantilever beam under vibration, converting the mechanical strain into changes in optical signals via optical fibers, thereby achieving the measurement of vibration parameters.

[0004] Existing cantilever beam fiber optic vibration sensors allow for flexible tuning of the sensor's response frequency bandwidth, resonant frequency, and sensitivity by adjusting the length of the vibrating portion of the spring and changing the counterweight. However, sensitivity and frequency response range are somewhat contradictory; higher sensitivity results in a lower frequency response range. Achieving a balance between the two significantly limits their achievable extreme values, narrowing their application range. Therefore, current sensors cannot meet the requirements for applications with large response frequency bandwidth or / and high sensitivity. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a tunable fiber optic vibration sensor device, system, and method that meets the application requirements of a large response frequency bandwidth and / or sensitivity range.

[0006] The technical solution adopted in this invention is as follows: This invention provides a first tunable fiber optic vibration sensor device, comprising a first fiber optic vibration sensor, the structure of which is as follows: Includes spring clips, sliders, adjusting components, mass blocks, bases, and optical fibers; The spring sheet is in the shape of an isosceles trapezoid, and the thickness and width of the spring sheet change linearly along the length direction of the spring sheet in the same trend, so that the two ends of the spring sheet in the length direction are respectively a wide and thick end and a narrow and thin end. The thick end of the spring is connected to the mass block, and the thin end is connected to the base; The spring sheet is provided with a sliding connection part, which slides with the slider, so that the slider moves along the length direction of the spring sheet; The adjusting member is used to fix the slider and the spring piece; The optical fiber has coupling points that are respectively connected to the base and the mass block, and the coupling point connected to the mass block can vibrate synchronously with the mass block.

[0007] The further technical solution is as follows: From the narrow end to the wide end, the thickness of the spring sheet increases linearly from 0.6 mm to 1.2 mm, and the width of the spring sheet increases linearly from 8 mm to 24 mm.

[0008] The sliding connection part is a rectangular groove, the center line of which coincides with the center line of the isosceles trapezoid.

[0009] One end of the rectangular groove extends to the narrow end, allowing the slider to fit against the base during tuning.

[0010] The present invention also provides an optical fiber vibration sensing system, which includes the first tunable optical fiber vibration sensor device described above.

[0011] The present invention also provides an optical fiber vibration sensing method, which employs the first tunable optical fiber vibration sensor device described above.

[0012] The present invention also provides a second tunable fiber optic vibration sensor device, comprising a second fiber optic vibration sensor, the structure of which is as follows: Includes spring clips, sliders, adjusting components, mass blocks, bases, and optical fibers; The spring sheet is in the shape of an isosceles trapezoid, and the thickness and width of the spring sheet change linearly along the length direction of the spring sheet in the same trend, so that the two ends of the spring sheet in the length direction are respectively a wide and thick end and a narrow and thin end. The thick end of the spring is connected to the base, and the thin end is connected to the mass block; The spring sheet is provided with a sliding connection part, which slides with the slider, so that the slider moves along the length direction of the spring sheet; The adjusting member is used to fix the slider and the spring piece; The optical fiber has coupling points that are respectively connected to the base and the mass block, and the coupling point connected to the mass block can vibrate synchronously with the mass block.

[0013] As a further improvement to the above technical solution: The sliding connection part is a rectangular groove, the center line of which coincides with the center line of the isosceles trapezoid. One end of the rectangular groove extends to the thick end, allowing the slider to fit against the base during tuning.

[0014] The present invention also provides an optical fiber vibration sensing system, which includes the second tunable optical fiber vibration sensor device.

[0015] The present invention also provides an optical fiber vibration sensing method, which employs the second tunable optical fiber vibration sensor device.

[0016] The beneficial effects of this invention are as follows: This invention improves the structure of a cantilever beam spring plate based on the premise that the length of the spring plate changes in the same direction as the sensitivity, but in the opposite direction to the frequency response range; and that the width and thickness change in the same direction as the frequency response range, but in the opposite direction to the sensitivity. The width and thickness of the spring plate are designed as a non-uniform structure that changes linearly and uniformly along its length. This allows for simultaneous changes in the width and thickness of the vibrating portion of the spring plate during tuning, providing more possibilities for adjusting sensitivity and frequency response range. Based on this, different connection methods are used between the two ends of the spring plate with different structural characteristics along its length and a mass block and base to obtain a first fiber optic vibration sensor and a second fiber optic sensor.

[0017] The first fiber optic vibration sensor, based on its tunable length, exhibits a superimposed effect in sensitivity and resonant frequency tuning, achieving a wider tuning range suitable for quickly and accurately locating internal fault sources in equipment. The second fiber optic vibration sensor, also based on its tunable length, provides a balanced effect in sensitivity and resonant frequency tuning, suitable for early warning and rapid location of fault sources externally. When used individually, both sensors, compared to traditional cantilever fiber optic vibration sensors, feature a non-uniform spring design, resulting in a wider tuning range. Furthermore, they can be used together to meet various application requirements, providing a flexible and economical method to improve the applicability of cantilever fiber optic vibration sensors to diverse situations.

[0018] Other features and advantages of the invention will be set forth in the following description or may be learned by practicing the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the first fiber optic vibration sensor according to Embodiment 1 of the present invention.

[0020] Figure 2 This is a schematic diagram of the spring structure according to Embodiment 1 of the present invention.

[0021] Figure 3 for Figure 1 A bottom view.

[0022] Figure 4 This is a schematic diagram of the structure of the first fiber optic vibration sensor in Embodiment 2 of the present invention.

[0023] Figure 5 This is a schematic diagram of the spring structure in Embodiment 2 of the present invention.

[0024] Figure 6 for Figure 4 A bottom view.

[0025] Figure 7 This is a schematic diagram of the fiber optic vibration sensing system in Embodiment 3 of the present invention.

[0026] Figure 8 The response characteristics of the first fiber optic vibration sensor in Embodiment 3 of the present invention under different actual vibration lengths are shown.

[0027] Figure 9 The response characteristics of the second fiber optic vibration sensor in Embodiment 3 of the present invention under different actual vibration lengths are shown.

[0028] In the figure: 1. DFB cavity laser; 2. Fiber optic vibration sensor; 3. Photodetector; 4. Multi-channel data acquisition system; 5. Data processing system; 6. Computer; 7. Base; 8. Spring; 9. Mass block; 10. Slider; 11. Adjustment component; 12. Fiber optic cable; 81. Sliding connection; 82. Connecting section; 801. Narrow end; 802. Wide end. Detailed Implementation

[0029] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0030] Example 1

[0031] See Figure 1 , Figure 2 This embodiment of a tunable fiber optic vibration sensor device includes a first fiber optic vibration sensor, the structure of which is as follows: It includes a spring piece 8, a slider 10, an adjusting component 11, a mass block 9, a base 7, and an optical fiber 12; The spring 8 is an isosceles trapezoid. The thickness and width of the spring 8 change linearly along the length of the spring 8 in the same trend, so that the two ends of the spring 8 in the length direction are respectively a wide and thick end 802 and a narrow and thin end 801. The thick end 802 of the spring 8 is connected to the mass block 9, and the thin end 801 is connected to the base 7; The spring piece 8 is provided with a sliding connection part 81, which is slidably engaged with the slider 10, so that the slider 10 moves along the length direction of the spring piece 8; Adjusting element 11 is used to fix slider 10 and spring 8; The optical fiber 12 has coupling points that are connected to the base 7 and the mass block 9 respectively, and the coupling point connected to the mass block 9 can vibrate synchronously with the mass block 9.

[0032] As a preferred embodiment, the thickness of the spring piece 8 preferably increases linearly from 0.6 mm to 1.2 mm from the narrow end 801 to the wide end 802, and the width of the spring piece 8 preferably increases linearly from 8 mm to 24 mm. The specific dimensions can be adjusted according to the length of the spring piece 8 and actual needs.

[0033] As a preferred embodiment, the sliding connection 81 is a rectangular groove, the center line of which coincides with the center line of the isosceles trapezoid.

[0034] As a preferred embodiment, one end of the rectangular groove extends to the narrow end 801, so that the slider 10 can fit against the base 7 during the tuning process.

[0035] As a preferred embodiment, the adjusting element 11 is a tuning screw.

[0036] As a preferred embodiment, the narrow end 801 is provided with a connecting section 82, which is used to embed into the base 7 and to fix the connection by a locking member.

[0037] As a preferred method, the mass block 9 is flatly attached to the spring piece 8 using polyester adhesive.

[0038] As a preferred method, polyester adhesive is used to bond the two connecting parts of the optical fiber 12 to the base 7 and the mass block 9 respectively.

[0039] As a preferred embodiment, optical fiber 12 is a core-diameter mismatched optical fiber, composed of single-mode fiber, large-core-diameter fiber, and single-mode fiber. The core-diameter mismatched optical fiber can be a multi-clad fiber, a coreless fiber, an empty-core fiber, a step-index multimode fiber, a few-mode fiber, a tapered fiber, a multi-core fiber, a photonic crystal fiber, or a tapered fiber.

[0040] As a preferred option, the spring 8 is made of metal.

[0041] As a preferred approach, considering factors such as force and aesthetics, the slider 9 can be designed to be taller, with a cutout at the top to allow the optical fiber 12 to pass through. It is understood that, depending on actual needs, the height can be reduced, and the cutout at the top can be omitted.

[0042] This embodiment constructs a single-degree-of-freedom cantilever beam-type first fiber optic vibration sensor based on a spring-loaded element. The base is used to fix the spring-loaded element. The slider can slide freely along the sliding connection on the spring-loaded element. After being adjusted to a set position, it is locked by an adjusting member to achieve tuning. When retuning is required, the adjusting member is loosened, the slider position is adjusted again, and then locked again. The portion of the spring-loaded element located between the slider and the mass block is the actual vibratory part, which can be used to amplify the vibration signal and maintain a linear response. The mass block amplifies the acceleration signal through inertial force. The optical fiber is fixed to the base and the mass block through two coupling points, respectively, and can convert the vibration into a corresponding optical signal.

[0043] In this embodiment, the spring is designed as an isosceles trapezoid, with its thickness and width gradually changing along its length. Specifically, the thickness and width increase linearly from the narrow end to the wide end. When tuning by adjusting the position of the slider on the spring, not only is the length of the actual vibrating part changed, but the area of ​​the cross-section of this vibrating part (the surface perpendicular to the length direction of the spring) also changes accordingly. This achieves simultaneous adjustment of the length, width, and thickness of the actual vibrating part, thereby synergistically adjusting the sensor's sensitivity and frequency response range.

[0044] The specific operation procedure and principle for adjusting the sensitivity and frequency response range of the first fiber optic vibration sensor are as follows: See Figure 3 In this state, slider 10 is in the middle position. Releasing adjustment component 11 causes slider 10 to move to the right (closer to mass block 9) along the straight line shown in the diagram. The actual vibrating length of the spring 8 shortens, while its widest and thickest values ​​increase. This has a cumulative effect, reducing the sensor's sensitivity and simultaneously increasing its frequency response range. Conversely, moving slider 10 to the left along the straight line shows that the actual vibrating length of the spring 8 lengthens, while its widest and thickest values ​​decrease. This has a cumulative effect, increasing the sensor's sensitivity and simultaneously decreasing its frequency response range. Therefore, similar to traditional cantilever beam sensors using ordinary spring structures, adjusting slider 10 in a certain direction results in opposite trends in the sensitivity and frequency response range of the first fiber optic sensor. However, due to the cumulative effect, the extreme values ​​of both characteristics are greatly enhanced.

[0045] As can be seen from the above, when slider 10 is adjusted to the left, especially when it is close to the base 7, the first fiber optic vibration sensor can have high sensitivity and can detect vibration responses in a lower frequency range. It is particularly suitable for scenarios where high sensitivity is required but the frequency response range is not critical. For example, after determining the fault area of ​​the electromechanical equipment from the equipment casing, the first fiber optic vibration sensor can be used to further detect the equipment inside (where the frequency response range requirement is not high), thereby accurately locating the fault source by utilizing its high sensitivity characteristics.

[0046] Example 2

[0047] See Figure 4 , Figure 5 This embodiment of a tunable fiber optic vibration sensor device includes a second fiber optic vibration sensor. Compared to the first fiber optic vibration sensor in Embodiment 1, its structure differs in that, while other structures and corresponding connections remain the same, the thicker end 802 of the spring 8 is connected to the base 7, and the thinner end 801 is connected to the mass block 9. That is, the spring in this embodiment has the same structural features as in Embodiment 1, but its connection to the base 7 and mass block 9 is reversed. The remaining structures and corresponding connections are the same as in Embodiment 1.

[0048] As a preferred embodiment, the sliding connection 81 is a rectangular groove, the center line of which coincides with the center line of the isosceles trapezoid.

[0049] As a preferred embodiment, one end of the rectangular groove extends to the wide and thick end 802, so that the slider 10 can fit against the base 7 during the tuning process.

[0050] As can be seen from Embodiment 1, the second fiber optic vibration sensor in this embodiment is also a single-degree-of-freedom cantilever beam fiber optic vibration sensor based on a spring sheet. The function of each component can be found in the description of Embodiment 1.

[0051] The specific operation procedure and principle for adjusting the sensitivity and frequency response range of the second fiber optic vibration sensor are as follows: See Figure 6 In this state, slider 10 is in the middle position. Release the adjusting piece 11 and move slider 10 to the right (closer to mass block 9) along the straight line shown in the diagram. The actual vibrating length of the spring piece 8 becomes shorter, and its widest and thickest values ​​decrease. Although length has a significant impact on frequency response range and sensitivity, while the frequency response range increases and sensitivity decreases as the length decreases, the changes in width and thickness balance the trend of decreasing sensitivity, ensuring that the sensitivity does not decrease significantly as the frequency response range expands.

[0052] Compared to the first fiber optic vibration sensor in Embodiment 1, the second fiber optic vibration sensor in this embodiment does not achieve high extreme values ​​in terms of sensitivity and frequency response range. However, it maintains a relatively balanced frequency response range and sensitivity throughout the entire sliding process of the slider 10 in any direction. That is, when the sensitivity is high, the frequency response range is not too low, and vice versa. This makes it highly suitable for early warning work in vibration detection and fault diagnosis of electromechanical equipment such as large blades and elevator drive shafts. Early warning requires a high frequency response range and a certain level of sensitivity, which the second fiber optic vibration sensor precisely meets. By installing the sensor on the equipment casing, fault areas can be quickly detected in advance. Based on this, further detection of the internal space of the equipment can be performed using the first fiber optic vibration sensor from Embodiment 1, thereby quickly pinpointing the fault location.

[0053] In practical applications, the first fiber optic vibration sensor and the second fiber optic vibration sensor can be used individually or in combination, depending on the characteristics of the detection environment and other actual needs.

[0054] Example 3

[0055] This embodiment provides an optical fiber vibration sensing system, which uses the tunable optical fiber vibration sensor device described in Embodiment 1 or Embodiment 2.

[0056] See Figure 7 As a specific implementation, the fiber optic vibration sensing system includes: a DFB cavity laser 1, a first fiber optic vibration sensor in Embodiment 1 or a second fiber optic vibration sensor in Embodiment 2, a photodetector 3, a multi-channel data acquisition system 4, a demodulation circuit and data processing system 5, and a computer 6; wherein, the output end of the DFB cavity laser 1 is connected to the input end of the first fiber optic vibration sensor 2, and the output end of the first fiber optic vibration sensor 2 is connected to the input end of the photodetector 3; these three devices are connected in series to form a vibration signal sensing and detection channel, and the output end of the photodetector 3 is connected in series with the multi-channel data acquisition system 4, the demodulation circuit and data processing system 5, and the computer 6 for display.

[0057] For ease of description, the first fiber optic vibration sensor in Embodiment 1 or the second fiber optic vibration sensor in Embodiment 2 will be referred to as a fiber optic vibration sensor. Figure 7 The mark in is 2.

[0058] The working principle of the system in this embodiment is as follows: The light emitted by the DFB cavity laser 1 enters the fiber vibration sensor 2. Since the self-focusing large-core fiber and the single-mode fiber are fused together by a fusion splicer, when an external physical signal enters the large-core fiber from the single-mode fiber, it will excite a variety of higher-order modes. Since the propagation constants of each mode are different, there will be a certain phase difference between the modes under the same optical path. When these modes meet and superimpose during propagation, they will form a multimode interference phenomenon. When light enters the single-mode fiber from the self-focusing large-core fiber, its coupling efficiency changes with the change of the external physical signal. When a vibration signal acts on the fiber optic vibration sensor 2, the vibration causes the spring 8 to vibrate. The spring 8 causes the coupling point with the fiber optic 12 to shift, thus changing the coupling efficiency of the fiber optic 12 when it enters the single-mode fiber from the self-focusing large-core fiber. When the optical signal is output from the fiber optic vibration sensor 2, the change in the intensity of the optical signal corresponds to the frequency of the vibration signal. Then the optical signal enters the photodetector 3. The electrical signal output after passing through the photodetector 3 is acquired by the multi-channel data acquisition system 4, and then demodulated by the demodulation circuit and the data processing system 5 to obtain the real-time change of the vibration signal contained in the electrical signal, which is then displayed by the computer 6.

[0059] In a specific implementation, the demodulation circuit and data processing system 5 includes a filtering unit, a Fourier transform unit, an inverter unit, and a spectrum analysis unit; the filtering unit includes a filter amplifier and a low-pass filter; the filter amplifier conditions the signal output by the photodetector, filtering out high-frequency noise while amplifying the signal.

[0060] In a specific implementation, a DFB cavity laser 1, an optical fiber vibration sensor 2, and a photodetector 3 are connected in series to form a sensing channel. The multiple sensing channels are connected to different signal acquisition terminals of a multi-channel data acquisition system 4. After the photoelectric signals of different channels are acquired synchronously by the multi-channel data acquisition system 4, the signals are analyzed in real time by the demodulation circuit and the data processing system 5 to achieve distributed multi-point real-time monitoring.

[0061] Since the signal output by photodetector 3 has a DC bias, which is difficult to remove with hardware, a Fourier transform unit is used to perform an FFT on the signal to clear the complex number corresponding to 0Hz to zero. Then, the FFT-transformed data is inverted by an inverter unit to remove the DC component from the signal. Next, a low-pass filter (using a third-order Chebyshev filter) is used to perform a second filtering on the signal to filter out noise introduced by the data acquisition card and the filter amplifier. Finally, the filtered signal is subjected to spectral analysis.

[0062] The above system layout and working principle are well-known attempts in the field of fiber optic vibration sensing technology. Those skilled in the art can understand how to implement them based on the above description and well-known attempts.

[0063] To further verify the performance of the fiber optic vibration sensor in this embodiment, the first and second fiber optic vibration sensors were tested using a vibration table (ESS-050, DongLing Tech). A standard piezoelectric accelerometer was mounted on the vibration table to calibrate the vibration signal generated by the table in real time. The required vibration acceleration signal was applied to the fiber optic vibration sensor through the vibration table. By rotating the tuning nut and sliding the slider, the frequency response and sensitivity of the sensor were tested at different slider positions. The test results are as follows: (1) For the first fiber optic sensor, under the conditions that the mass of the mass block is 8.5g and the acceleration is 0.6 times the gravitational acceleration, the distance between the right end of the slider and the mass block, i.e. the actual vibration length of the spring, is adjusted to 16mm, 14mm, 12mm, 10mm and 8mm respectively. The frequency response of the sensor is calibrated and the experimental data is analyzed and statistically analyzed. The results show that the actual vibration length of the spring is 16mm, 14mm, 12mm, 10mm and 8mm, and the corresponding sensor response frequencies are 10~650Hz, 10~1360Hz, 10~2000Hz, 10~2780Hz and 10~3500Hz respectively. A calibration experiment was conducted on the sensor sensitivity, and the experimental data were analyzed and statistically analyzed. The results at a frequency of 200 Hz showed that the actual vibration lengths of the spring were 16 mm, 14 mm, 12 mm, 10 mm, and 8 mm, and the average sensitivities of the sensor were 700 mV / g, 550 mV / g, 400 mV / g, 250 mV / g, and 125 mV / g, respectively, with good linear fitting.

[0064] like Figure 8 The figure shows the response characteristics of the first fiber optic sensor under different vibration lengths. Compared with the traditional vibration sensor that only changes the length of the cantilever beam, its frequency response and sensitivity are greatly improved in the lower frequency range and the frequency response range at relatively high sensitivity is also expanded by the superposition effect of changing both the width and thickness.

[0065] (2) For the second fiber optic sensor, under the condition that the mass of the mass block is 8.5g and the acceleration is 0.6 times the gravitational acceleration, the distance between the right end of the slider and the mass block (the actual vibration length of the spring) is adjusted to 16mm, 14mm, 12mm, 10mm and 8mm. The frequency response of the sensor is calibrated and the experimental data is analyzed and statistically analyzed. The results show that the actual vibration length of the spring is 16mm, 14mm, 12mm, 10mm and 8mm, and the response frequencies of the sensor are 10-1250Hz, 10-1440Hz, 10-1625Hz, 10-1810Hz and 10-2000Hz, respectively. A calibration experiment was conducted on the sensor sensitivity, and the experimental data were analyzed and statistically analyzed. The results at a frequency of 200 Hz showed that the actual vibration lengths of the spring were 16 mm, 14 mm, 12 mm, 10 mm, and 8 mm, and the average sensitivities of the sensor were 550 mV / g, 470 mV / g, 386 mV / g, 305 mV / g, and 220 mV / g, respectively, with good linear fitting.

[0066] like Figure 9 The figure shows the response characteristics of the second fiber optic sensor under different vibration lengths. Compared with the first fiber optic sensor, its frequency response and sensitivity are more concentrated due to the balancing effect of changes in both width and thickness. This allows for a more refined determination of the required sensitivity within a specific frequency range when providing early warning of electromechanical equipment faults.

[0067] Example 4

[0068] This embodiment provides an optical fiber vibration sensing method, which uses the optical fiber vibration sensing system described in Embodiment 3.

[0069] It will be understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tunable fiber optic vibration sensor apparatus, characterized by, Including the first fiber optic vibration sensor, its structure is as follows: It includes a spring (8), a slider (10), an adjusting component (11), a mass block (9), a base (7), and an optical fiber (12); The spring piece (8) is an isosceles trapezoid. The thickness and width of the spring piece (8) change linearly along the length direction of the spring piece (8) in the same trend, so that the two ends of the spring piece (8) in the length direction are respectively a wide and thick end (802) and a narrow and thin end (801). The thick end (802) of the spring (8) is connected to the mass block (9), and the thin end (801) is connected to the base (7); The spring (8) is provided with a sliding connection part (81), which slides with the slider (10) to make the slider (10) move along the length direction of the spring (8); The adjusting member (11) is used to fix the slider (10) and the spring piece (8); The optical fiber (12) has coupling points that are respectively connected to the base (7) and the mass block (9), and the coupling points connected to the mass block (9) can vibrate synchronously with the mass block (9).

2. The tunable fiber optic vibration sensor apparatus of claim 1, wherein, From the narrow end (801) to the wide end (802), the thickness of the spring piece (8) increases linearly from 0.6 mm to 1.2 mm, and the width of the spring piece (8) increases linearly from 8 mm to 24 mm.

3. The tunable fiber optic vibration sensor apparatus of claim 1, wherein, The sliding connection (81) is a rectangular groove, the center line of which coincides with the center line of the isosceles trapezoid.

4. The tunable fiber optic vibration sensor apparatus of claim 3, wherein, One end of the rectangular groove extends to the narrow end (801), so that the slider (10) can fit against the base (7) during the tuning process.

5. An optical fiber vibration sensing system, characterized by, The tunable fiber optic vibration sensor device according to any one of claims 1-4 is used.

6. A fiber optic vibration sensing method, characterized in that, The tunable fiber optic vibration sensor device according to any one of claims 1-4 is used.

7. A tunable fiber optic vibration sensor apparatus, characterized by, Including a second fiber optic vibration sensor, its structure is as follows: It includes a spring (8), a slider (10), an adjusting component (11), a mass block (9), a base (7), and an optical fiber (12); The spring piece (8) is an isosceles trapezoid. The thickness and width of the spring piece (8) change linearly along the length direction of the spring piece (8) in the same trend, so that the two ends of the spring piece (8) in the length direction are respectively a wide and thick end (802) and a narrow and thin end (801). The thick end (802) of the spring (8) is connected to the base (7), and the thin end (801) is connected to the mass block (9); The spring (8) is provided with a sliding connection part (81), which slides with the slider (10) to make the slider (10) move along the length direction of the spring (8); The adjusting member (11) is used to fix the slider (10) and the spring piece (8); The optical fiber (12) has coupling points that are respectively connected to the base (7) and the mass block (9), and the coupling points connected to the mass block (9) can vibrate synchronously with the mass block (9).

8. The tunable fiber optic vibration sensor apparatus of claim 7, wherein, The sliding connection (81) is a rectangular groove, the center line of which coincides with the center line of the isosceles trapezoid; One end of the rectangular groove extends to the wide end (802), so that the slider (10) can fit against the base (7) during the tuning process.

9. An optical fiber vibration sensing system, characterized by, The tunable fiber optic vibration sensor device described in claim 7 or 8 is used.

10. An optical fiber vibration sensing method, characterized by, The tunable fiber optic vibration sensor device described in claim 7 or 8 is used.

Images