A fiber grating pressure sensor and pressure calculation method thereof

Abstract

The present invention provides a fiber Bragg grating pressure sensor and a pressure calculation method thereof, comprising a pressurized platform, a first oblique beam, a second oblique beam, and a fiber Bragg grating, wherein the first oblique beam and the second oblique beam are symmetrically arranged on both sides of the pressurized platform, a first serpentine elastic structure is formed on the first oblique beam, a second serpentine elastic structure is formed on the second oblique beam, the fiber Bragg grating is installed between the first oblique beam and the second oblique beam, the first serpentine elastic structure is located between the pressurized platform and the connection point between the first oblique beam and the fiber Bragg grating, the second serpentine elastic structure is located between the pressurized platform and the connection point between the second oblique beam and the fiber Bragg grating, and when the pressurized platform is subjected to external pressure, the portion of the fiber Bragg grating located between the first oblique beam and the second oblique beam produces corresponding deformation. The present invention can achieve the technical effects of simple structure, low cost, high sensitivity, and strong stability.

Description

Technical Field

[0001] The present invention relates to the field of fiber grating sensing detection technology, and in particular to a fiber grating pressure sensor and a pressure calculation method thereof. Background Art

[0002] Fiber Bragg grating (FBG) pressure sensor is developing rapidly as an emerging pressure sensor. With the expansion of the application of fiber optic sensors, the demand for high-sensitivity fiber optic pressure sensors is becoming more and more obvious. Fiber optic sensors can work in dangerous and harsh environments with high temperature, corrosion, strong electromagnetic fields, and flammable and explosive environments. This feature makes fiber optic grating sensors widely used in structural health monitoring, oil exploration, civil engineering, aerospace and other fields. The signal of the fiber optic Bragg grating pressure sensor adopts wavelength modulation. Compared with other fiber optic sensors, it is less susceptible to the influence of external parameters. It has the characteristics of high accuracy, good stability, easy distributed monitoring, and easy demodulation. For this reason, fiber optic Bragg grating pressure sensors have attracted much attention in recent years. New high-sensitivity fiber optic Bragg grating sensor research has been constantly innovating.

[0003] That is, how to provide a new fiber Bragg grating pressure sensor to achieve the technical effect of enhancing sensitivity is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0004] In view of the above problems, the present invention aims to provide a fiber Bragg grating pressure sensor and a detection method to solve at least one of the above technical problems.

[0005] In order to at least solve the above technical problems, in the first aspect, the present invention provides a fiber Bragg grating pressure sensor, which includes: a pressurizing platform, a first oblique beam, a second oblique beam, and a fiber Bragg grating; the first oblique beam and the second oblique beam are connected to both sides of the pressurizing platform at an angle symmetrically, a first serpentine elastic structure is formed on the first oblique beam, and a second serpentine elastic structure is formed on the second oblique beam, the fiber Bragg grating is installed between the first oblique beam and the second oblique beam, the first serpentine elastic structure is located between the pressurizing platform and the connection point between the first oblique beam and the fiber Bragg grating and is fixedly connected to the first oblique beam and the second oblique beam respectively, and the second serpentine elastic structure is located between the pressurizing platform and the connection point between the second oblique beam and the fiber Bragg grating; when the pressurizing platform is subjected to external pressure, the part of the fiber Bragg grating located between the first oblique beam and the second oblique beam produces corresponding deformation.

[0006] Preferably, the fiber Bragg grating pressure sensor further comprises a first base and a second base;

[0007] The first base is arranged on a side of the first inclined beam away from the pressurizing platform, the second base is arranged on a side of the second inclined beam away from the pressurizing platform, and both the first base and the second base are arranged parallel to the pressurizing platform.

[0008] Preferably, the pressurizing platform, the first oblique beam, the second oblique beam, the first base and the second base are integrally formed.

[0009] Preferably, a plurality of first grooves are formed inwardly on the left side wall of the first oblique beam, and a plurality of second grooves are formed inwardly on the right side wall of the first oblique beam, and the first grooves and the second grooves are arranged alternately to form the first serpentine elastic structure;

[0010] A plurality of third grooves are formed inwardly on the left side wall of the second oblique beam, and a plurality of fourth grooves are formed inwardly on the right side wall of the second oblique beam. The third grooves and the fourth grooves are alternately arranged to form the second serpentine elastic structure.

[0011] In a second aspect, the present invention provides a pressure calculation method, which is applied to pressure detection of a fiber Bragg grating pressure sensor as described in any one of the first aspects, and the method comprises:

[0012] Calculating the final deformation amount of the fiber Bragg grating when the pressurized platform is subjected to external pressure, and obtaining the wavelength offset of the fiber Bragg grating corresponding to the final deformation amount of the fiber Bragg grating;

[0013] Calculating the sensitivity enhancement coefficient generated by the first serpentine elastic structure and the second serpentine elastic structure according to the final deformation amount of the fiber grating;

[0014] The external pressure is calculated by using the fiber grating strain formula according to the wavelength offset, the final deformation and the sensitivity enhancement coefficient.

[0015] Preferably, the calculation of the final deformation amount of the fiber Bragg grating generated when the pressurizing platform is subjected to external pressure includes:

[0016] calculating the bending stiffness of the first serpentine elastic structure or the second serpentine elastic structure;

[0017] When the pressurizing platform is subjected to external pressure, a first deformation displacement of the optical fiber Bragg grating caused by the external pressure when the first oblique beam and the second oblique beam are tempered is calculated according to the bending stiffness, and a second deformation displacement of the optical fiber Bragg grating caused by the external pressure when the pressurizing platform is tempered is calculated;

[0018] The first deformation displacement and the second deformation displacement are summed to obtain the final deformation amount of the fiber Bragg grating generated when the pressurizing platform is subjected to external pressure.

[0019] Preferably, the first deformation displacement is , the second deformation displacement is , the calculation formula of the first deformation displacement is:

[0020]

[0021] The calculation formula of the second deformation displacement is:

[0022]

[0023] Wherein, P is the external pressure, is the length of the pressurized platform, is the moment of inertia of the pressurized platform; is the angle between the first inclined beam and the pressurizing platform or the angle between the second inclined beam and the pressurizing platform, is an acute angle; is the length of the first oblique beam or the second oblique beam; is the bending stiffness;

[0024] The calculation formula of the bending stiffness is:

[0025]

[0026] in, is the number of the first groove and the second groove in the first serpentine elastic structure, or the number of the third groove and the fourth groove in the second serpentine elastic structure; is the moment of inertia of the first serpentine elastic structure or the second serpentine elastic structure; is the width of the first groove, the second groove, the third groove, or the fourth groove; is the depth of the first groove, the second groove, the third groove, or the fourth groove.

[0027] Preferably, the calculation of the sensitivity enhancement coefficient generated by the first serpentine elastic structure and the second serpentine elastic structure according to the final deformation amount of the fiber Bragg grating includes:

[0028] Calculate the final average strain of the fiber Bragg grating according to the final deformation amount when considering the strain influence of the first serpentine elastic structure and the second serpentine elastic structure , ,in, is the length of the fiber Bragg grating between the first oblique beam and the second oblique beam before deformation;

[0029] Calculating the original deformation of the fiber Bragg grating when the strain influence of the first serpentine elastic structure and the second serpentine elastic structure is not considered, and calculating the original average strain of the fiber Bragg grating corresponding to the original deformation ;

[0030] The sensitivity enhancement coefficient generated by the first serpentine elastic structure and the second serpentine elastic structure is calculated according to the sensitivity enhancement coefficient calculation formula. , the calculation formula of the sensitization coefficient is:

[0031]

[0032] Preferably, the calculating of the original deformation amount of the fiber Bragg grating without considering the strain influence of the first serpentine elastic structure and the second serpentine elastic structure comprises:

[0033] When the pressurized platform is subjected to external pressure, the third deformation displacement of the optical fiber Bragg grating caused by the external pressure after the first oblique beam and the second oblique beam are tempered is calculated without considering the strain influence of the first serpentine elastic structure and the second serpentine elastic structure, and the fourth deformation displacement of the optical fiber Bragg grating caused by the external pressure after the pressurized platform is tempered is calculated;

[0034] The third deformation displacement and the fourth deformation displacement are summed to obtain the original deformation amount of the fiber grating.

[0035] Preferably, the third deformation displacement is , the fourth deformation displacement is , the calculation formula of the third deformation displacement is:

[0036]

[0037] The calculation formula of the fourth deformation displacement is:

[0038]

[0039] in, is the moment of inertia of the first oblique beam or the second oblique beam.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] A fiber Bragg grating pressure sensor provided by the present invention comprises a pressurizing platform, a first oblique beam, a second oblique beam, and a fiber Bragg grating, wherein the first oblique beam and the second oblique beam are angularly symmetrically arranged on both sides of the pressurizing platform, and the relative distance between one end of the first oblique beam away from the pressurizing platform and one end of the second oblique beam away from the pressurizing platform is greater than the length of the pressurizing platform, a first serpentine elastic structure is formed on the first oblique beam, and a second serpentine elastic structure is formed on the second oblique beam, and the fiber Bragg grating is installed between the first oblique beam and the second oblique beam, the first serpentine elastic structure is located between the pressurizing platform and the connection point between the first oblique beam and the fiber Bragg grating, the second serpentine elastic structure is located between the pressurizing platform and the connection point between the second oblique beam and the fiber Bragg grating, and the first serpentine elastic structure and the second serpentine elastic structure are symmetrical relative to the pressurizing platform, so as to enhance the sensitivity of the overall structure through the serpentine elastic structure, when the pressurizing platform is subjected to external pressure, the portion of the fiber Bragg grating located between the first oblique beam and the second oblique beam produces corresponding deformation and the wavelength of the fiber Bragg grating will also shift accordingly, thereby realizing the detection of external pressure. The fiber grating pressure sensor provided by the present invention has simple structure, low cost, high sensitivity and strong stability.

[0042] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 This is a structural schematic diagram of a fiber Bragg grating pressure sensor provided by the present application;

[0045] Figure 2 It is a mechanical model diagram of the fiber Bragg grating sensor provided by the present application after being subjected to external pressure;

[0046] Figure 3 This application One-sided force-strain diagram;

[0047] Figure 4 This application One-sided force-strain diagram;

[0048] Figure 5 It is an overall dimension diagram of the fiber Bragg grating pressure sensor provided by the present application;

[0049] Figure 6 is a dimension diagram of the serpentine elastic structure provided in the present application;

[0050] Figure 7 It is a flow chart of the pressure calculation method provided in this application.

[0051] Reference numerals:

[0052] 1. Pressurized platform;

[0053] 2. The first oblique beam;

[0054] 21. The first serpentine elastic structure;

[0055] 3. The second inclined beam;

[0056] 31. Second serpentine elastic structure;

[0057] 4. The first base;

[0058] 5. Second base;

[0059] 6. Fiber Bragg grating. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention; the "and / or" keyword involved in this implementation represents both and, or. In other words, A and / or B mentioned in the embodiments of this specification represent both A and B, and A or B, and describe the three states of A and B. For example, A and / or B means: only A is included but not B; only B is included but not A; A and B are included.

[0061] Meanwhile, in the embodiments of this specification, when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time.

[0062] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0063] Embodiment 1

[0064] See also Figure 1 Specifically, in an embodiment of the fiber Bragg grating pressure sensor, the fiber Bragg grating pressure sensor includes a pressurizing platform 1, a first oblique beam 2, a second oblique beam 3, and a fiber Bragg grating 6; the first oblique beam 2 and the second oblique beam 3 are connected to both sides of the pressurizing platform 1 at an angle symmetrically, a first serpentine elastic structure 21 is formed on the first oblique beam 2, and a second serpentine elastic structure 31 is formed on the second oblique beam 3, the fiber Bragg grating 6 is installed between the first oblique beam 2 and the second oblique beam 3, the first serpentine elastic structure 21 is located between the pressurizing platform 1 and the connection point between the first oblique beam 2 and the fiber Bragg grating 6 and is fixedly connected to the first oblique beam 2 and the second oblique beam 3 respectively, the second serpentine elastic structure 31 is located between the pressurizing platform 1 and the connection point between the second oblique beam 3 and the fiber Bragg grating 6; when the pressurizing platform 1 is subjected to external pressure, the portion of the fiber Bragg grating 6 located between the first oblique beam 2 and the second oblique beam 3 produces corresponding deformation.

[0065] Specifically, an embodiment of the present invention provides a fiber Bragg grating pressure sensor, comprising a pressurized platform 1, a first inclined beam 2, a second inclined beam 3, and a fiber Bragg grating 6, wherein the first inclined beam 2 and the second inclined beam 3 are angularly symmetrically arranged on both sides of the pressurized platform 1, and the relative distance between one end of the first inclined beam 2 away from the pressurized platform 1 and one end of the second inclined beam 3 away from the pressurized platform 1 is greater than the length of the pressurized platform 1, a first serpentine elastic structure 21 is formed on the first inclined beam 2, a second serpentine elastic structure 31 is formed on the second inclined beam 3, and the fiber Bragg grating 6 is installed between the first inclined beam 2 and the second inclined beam 3, and the first serpentine elastic structure 21 is formed on the first inclined beam 2, and the second serpentine elastic structure 31 is formed on the second inclined beam 3. The elastic structure 21 is located between the pressurized platform 1 and the connection point between the first inclined beam 2 and the fiber Bragg grating 6, and the second serpentine elastic structure 31 is located between the pressurized platform 1 and the connection point between the second inclined beam 3 and the fiber Bragg grating 6, and the first serpentine elastic structure 21 and the second serpentine elastic structure 31 are symmetrical relative to the pressurized platform 1, so as to enhance the sensitivity of the overall structure through the serpentine elastic structure. When the pressurized platform 1 is subjected to external pressure, the portion of the fiber Bragg grating 6 located between the first inclined beam 2 and the second inclined beam 3 produces corresponding deformation and the wavelength of the fiber Bragg grating 6 also shifts accordingly, thereby realizing the detection of external pressure. The fiber Bragg grating pressure sensor provided by the embodiment of the present invention has simple structure, low cost, high sensitivity and strong stability.

[0066] As an implementable method, the fiber Bragg grating pressure sensor further includes a first base 4 and a second base 5; the first base 4 is arranged on the side of the first inclined beam 2 away from the pressurized platform 1, and the second base 5 is arranged on the side of the second inclined beam 3 away from the pressurized platform 1, and the first base 4 and the second base 5 are arranged parallel to the pressurized platform 1. By arranging the first base 4 on the side of the first inclined beam 2 away from the pressurized platform 1, and arranging the second base 5 on the side of the second inclined beam 3 away from the pressurized platform 1, the fiber Bragg grating pressure sensor of the present application can be connected and fixed to an external device through the base.

[0067] As a feasible method, the pressurizing platform 1, the first inclined beam 2, the second inclined beam 3, the first base 4 and the second base 5 are integrally formed, and the pressurizing platform 1, the first inclined beam 2, the second inclined beam 3, the first base 4 and the second base 5 are all made of elastic materials, such as aluminum alloy, copper alloy, stainless steel, etc.

[0068] As an achievable manner, a plurality of first grooves are formed inwardly on the left side wall of the first oblique beam 2, and a plurality of second grooves are formed inwardly on the right side wall of the first oblique beam 2, and the first grooves and the second grooves are arranged alternately to form the first serpentine elastic structure 21;

[0069] A plurality of third grooves are formed inwardly on the left side wall of the second oblique beam 3 , and a plurality of fourth grooves are formed inwardly on the right side wall of the second oblique beam 3 . The third grooves and the fourth grooves are alternately arranged to form the second serpentine elastic structure 31 .

[0070] Specifically, the range and sensitivity can be changed by changing the size of the serpentine elastic structure, the number of folds, such as the depth of the groove, the number of grooves, etc., so that it can be widely used in a variety of different environments. The first serpentine elastic structure 21 generally has 3-5 grooves (including the first groove and the second groove), and the second serpentine elastic structure 31 is symmetrical with the first serpentine elastic structure 21 relative to the pressurizing platform 1; and the depth of the groove does not exceed three quarters of the width of the inclined beam.

[0071] As a feasible method, the fiber grating 6 can be pasted on the base of the sensor, at which time the length of the fiber grating 6 before deformation between the first oblique beam 2 and the second oblique beam 3 is equal to the distance between the bottom ends of the first oblique beam 2 and the second oblique beam 3 (the top ends of the first oblique beam 2 and the second oblique beam 3 are connected to the pressurizing platform 1); or, a through hole is correspondingly provided near the bottom end or the bottom end position of the first oblique beam 2 and the second oblique beam 3 to pass the fiber grating 6 through the through hole and paste the fiber grating through the through hole.

[0072] Generally speaking, the first serpentine elastic structure 21 is arranged on the upper part of the first inclined beam 2 (the part close to the pressurizing platform 1), the second serpentine elastic structure 31 is arranged on the upper part of the second inclined beam 3 (the part close to the pressurizing platform 1) and corresponds to the structure of the first serpentine elastic structure 21, and the optical fiber Bragg grating is pasted on the lower part or the bottom of the first inclined beam 2 and the second inclined beam 3, and the pasting point (connection point) is symmetrical relative to the pressurizing platform 1.

[0073] The fiber grating pressure sensor provided in the present application can be embedded in plastic objects such as bracelets for pressure detection on the skin surface.

[0074] Embodiment 2

[0075] See also Figure 2-7 Specifically, the implementation method of the pressure calculation method is applied to the pressure detection of the fiber Bragg grating pressure sensor as described in any one of the first embodiments, and the method includes the following steps S110 to S130:

[0076] Step S110, calculating the final deformation amount of the fiber Bragg grating when the pressurized platform is subjected to external pressure, and obtaining the wavelength offset of the fiber Bragg grating corresponding to the final deformation amount of the fiber Bragg grating;

[0077] As an achievable manner, the calculation of the final deformation amount of the fiber Bragg grating generated when the pressurized platform is subjected to external pressure in the above step S110 specifically includes the following sub-steps:

[0078] Calculate the bending stiffness of the first serpentine elastic structure 21 or the second serpentine elastic structure 31

[0079] When the pressurizing platform is subjected to external pressure, the first deformation displacement of the optical fiber Bragg grating caused by the external pressure when the first oblique beam 2 and the second oblique beam 3 are tempered is calculated according to the bending stiffness, and the second deformation displacement of the optical fiber Bragg grating caused by the external pressure when the pressurizing platform 1 is tempered is calculated;

[0080] The first deformation displacement and the second deformation displacement are summed to obtain the final deformation amount of the fiber Bragg grating generated when the pressurizing platform is subjected to external pressure.

[0081] As a feasible method, let the first deformation displacement be , the second deformation displacement is , then the calculation formula for the first deformation displacement is:

[0082]

[0083] The calculation formula of the second deformation displacement is:

[0084]

[0085] Wherein, P is the external pressure, is the length of the pressurized platform 1, is the moment of inertia of the pressurizing platform 1; is Young's modulus; is the angle between the first inclined beam 2 and the pressurizing platform 1 or the angle between the second inclined beam 3 and the pressurizing platform 1, is an acute angle; is the length of the first oblique beam 2 or the second oblique beam 3; is the bending stiffness;

[0086] The calculation formula of the bending stiffness is:

[0087]

[0088] in, is the number of the first groove and the second groove in the first serpentine elastic structure 21, or the number of the third groove and the fourth groove in the second serpentine elastic structure 31; is Young's modulus; is the moment of inertia of the first serpentine elastic structure 21 or the second serpentine elastic structure 31; is the width of the first groove, the second groove, the third groove, or the fourth groove; is the depth of the first groove, the second groove, the third groove or the fourth groove (see Appendix Figure 6 label).

[0089] Specifically, Figure 2 As shown in FIG. 1 , it is a mechanical model diagram of the sensor of the present application after being subjected to external pressure. F1 and F2 are the internal forces generated by the arch rib structure under the action of the external pressure P, and θ is the arch foot angle of the arch rib structure. The force analysis of the arch rib yields:

[0090]

[0091]

[0092]

[0093] After the force P acts on the pressurized platform 1, the force P can be decomposed into the direction of the arch rib (the layout direction of the first inclined beam 2, such as Figure 2 The arch rib BC) and along the arch foot direction (the layout direction of the first base 4, such as Figure 2 Horizontal force in the arch foot CD) Since the two sides are symmetrical structures, the right side can be decomposed into the arch rib direction and horizontal arch foot direction , lateral tension and It will cause the fiber Bragg grating to have lateral strain. When the temperature remains unchanged, if the fiber Bragg grating is only subjected to uniform axial stress and the stress in other directions is 0, then when the serpentine elastic structure is not considered, the center wavelength drift of the fiber Bragg grating is With axial strain The relationship is:

[0094]

[0095] in, , is the original shape variable, is the third deformation displacement, is the fourth deformation displacement, is the length of the fiber Bragg grating between the first oblique beam 2 and the second oblique beam 3 before deformation;

[0096] When the serpentine elastic structure is considered, the central wavelength drift of the fiber Bragg grating is With axial strain The relationship is:

[0097]

[0098] in, ; is the final shape, is the third deformation displacement, is the fourth deformation displacement;

[0099] Then the fiber Bragg grating strain formula can be derived as follows:

[0100]

[0101] in, is the wavelength offset of the fiber grating; is the wavelength of the fiber Bragg grating before deformation; is the effective elastic coefficient of the fiber Bragg grating.

[0102] Then, after obtaining the relationship between the final deformation and pressure, the relationship and the sensitivity coefficient after considering the serpentine elastic structure are calculated. Substituting it into the fiber Bragg grating strain formula, the external pressure can be calculated.

[0103] When calculating the final deformation (considering the influence of the serpentine elastic structure):

[0104] like Figure 2As shown, since the sensor structure of the present application is a symmetrical structure, half of it is taken for analysis, and the BC part (the first inclined beam 2) is first rigidified by the superposition method to calculate the displacement caused by the AB part (pressurized platform 1). (As attached Figure 3 As shown in the figure), the AB part (pressurized platform 1) is tempered and the displacement caused by the BC part (first inclined beam 2) is calculated. (As attached Figure 4 As shown, attached Figure 4 middle, is the tangential component of the external pressure along the BC section, ), ignoring the compression of the AB part (pressurized platform 1) itself, ΔL AB , that is, ΔL AB =0, we can get and The calculation formula is:

[0105]

[0106]

[0107] Bending stiffness In is the moment of inertia of the first serpentine elastic structure 21 or the second serpentine elastic structure 31, which can be calculated by the following formula:

[0108]

[0109] Among them, Figure 4 As shown, is the distance between the adjacent first groove and the second groove in the first serpentine elastic structure 21, or the distance between the adjacent third groove and the fourth groove in the second serpentine elastic structure 31; It is the thickness of the first groove and the second groove in the first serpentine elastic structure 21 , and is also the thickness of the first inclined beam 2 or the second inclined beam 3 .

[0110] Step S120, calculating the sensitivity enhancement coefficient generated by the first serpentine elastic structure 21 and the second serpentine elastic structure 31 according to the final deformation amount of the fiber Bragg grating;

[0111] As an achievable manner, the calculation of the sensitivity enhancement coefficient generated by the first serpentine elastic structure 21 and the second serpentine elastic structure 31 according to the final deformation amount of the fiber Bragg grating involved in the above step S120 specifically includes the following sub-steps:

[0112] According to the final deformation amount, the final average strain of the fiber Bragg grating is calculated when the strain influence of the first serpentine elastic structure 21 and the second serpentine elastic structure 31 is considered. , ,in, is the length of the fiber Bragg grating between the first oblique beam 2 and the second oblique beam 3 before deformation;

[0113] Calculate the original deformation of the fiber Bragg grating when the strain effect of the first serpentine elastic structure 21 and the second serpentine elastic structure 31 is not considered, and calculate the original average strain of the fiber Bragg grating corresponding to the original deformation ;

[0114] The sensitivity enhancement coefficient generated by the first serpentine elastic structure 21 and the second serpentine elastic structure 31 is calculated according to the sensitivity enhancement coefficient calculation formula: , the calculation formula of the sensitization coefficient is:

[0115]

[0116] As an achievable manner, the calculation of the original deformation amount of the fiber Bragg grating without considering the strain influence of the first serpentine elastic structure 21 and the second serpentine elastic structure 31 includes:

[0117] When the pressurized platform is subjected to external pressure, the third deformation displacement of the optical fiber Bragg grating caused by the external pressure after the first oblique beam 2 and the second oblique beam 3 are tempered is calculated without considering the strain influence of the first serpentine elastic structure 21 and the second serpentine elastic structure 31, and the fourth deformation displacement of the optical fiber Bragg grating caused by the external pressure after the pressurized platform 1 is tempered is calculated;

[0118] The third deformation displacement and the fourth deformation displacement are summed to obtain the original deformation amount of the fiber grating.

[0119] As a feasible method, let the third deformation displacement be , the fourth deformation displacement is , the calculation formula of the third deformation displacement is:

[0120]

[0121] The calculation formula of the fourth deformation displacement is:

[0122]

[0123] in, is the moment of inertia of the first oblique beam 2 or the second oblique beam 3 .

[0124] It can be understood that when calculating the original deformation (without considering the influence of the serpentine elastic structure on the strain):

[0125] The calculation process can refer to Figure 2 As for the calculation method of the final deformation, since the sensor structure of the present application is a symmetrical structure, half of the structure is still taken for analysis. The BC part (the first inclined beam 2) is first rigidified by the superposition method to calculate the displacement of the CD part (the first base 4) caused by the AB part (the pressurized platform 1). , and then the AB part (pressurized platform 1) is tempered to calculate the displacement of the CD part (the first base 4) caused by the BC part (the BC part here is the first inclined beam 2 without considering the serpentine elastic structure) , ignoring the compression of the AB part itself ΔL AB , that is, ΔL AB =0, we can get and The calculation formulas are:

[0126]

[0127]

[0128]

[0129] in, is the thickness of the first inclined beam 2, the second inclined beam 3, and the pressurized platform 1, It is the width of the overall structure of the sensor of the present application (i.e., the width of the pressurized platform 1, the first base 4, the second base 5, the first inclined beam 2, and the second inclined beam 3).

[0130] Then the complete calculation formula of the sensitization coefficient can be derived as follows:

[0131]

[0132] Step S130, calculating the external pressure using a fiber Bragg grating strain formula according to the wavelength offset, the final deformation, and the sensitivity enhancement coefficient.

[0133] Specifically, the wavelength offset formula of the fiber Bragg grating can also be written as:

[0134]

[0135] The external pressure can be calculated based on the complete calculation formula of the sensitivity enhancement coefficient and the above-mentioned wavelength offset formula.

[0136] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0137] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A pressure calculation method, characterized in that: The method comprises: Calculating the final deformation amount of the fiber Bragg grating when the pressurized platform is subjected to external pressure, and obtaining the wavelength offset of the fiber Bragg grating corresponding to the final deformation amount; Calculating the sensitivity enhancement coefficient generated by the first serpentine elastic structure and the second serpentine elastic structure according to the final deformation amount; The external pressure is calculated by using a fiber grating strain formula according to the wavelength offset, the final deformation, and the sensitivity enhancement coefficient; The pressure calculation method is applied to a fiber Bragg grating pressure sensor, which includes a pressurizing platform, a first oblique beam, a second oblique beam, and a fiber Bragg grating; the first oblique beam and the second oblique beam are connected to both sides of the pressurizing platform at an angle of symmetry, a first serpentine elastic structure is formed on the first oblique beam, and a second serpentine elastic structure is formed on the second oblique beam, the fiber Bragg grating is installed between the first oblique beam and the second oblique beam and is fixedly connected to the first oblique beam and the second oblique beam respectively, the first serpentine elastic structure is located between the pressurizing platform and the connection point between the first oblique beam and the fiber Bragg grating, and the second serpentine elastic structure is located between the pressurizing platform and the connection point between the second oblique beam and the fiber Bragg grating; when the pressurizing platform is subjected to external pressure, the part of the fiber Bragg grating located between the first oblique beam and the second oblique beam produces corresponding deformation.

2. The pressure calculation method according to claim 1, characterized in that: The fiber Bragg grating pressure sensor further includes a first base and a second base; The first base is arranged on a side of the first inclined beam away from the pressurizing platform, the second base is arranged on a side of the second inclined beam away from the pressurizing platform, and both the first base and the second base are arranged parallel to the pressurizing platform.

3. The pressure calculation method according to claim 2, characterized in that: The pressurizing platform, the first oblique beam, the second oblique beam, the first base and the second base are integrally formed.

4. The pressure calculation method according to claim 3, characterized in that: A plurality of first grooves are formed inwardly on the left side wall of the first oblique beam, and a plurality of second grooves are formed inwardly on the right side wall of the first oblique beam, and the first grooves and the second grooves are arranged alternately to form the first serpentine elastic structure; A plurality of third grooves are formed inwardly on the left side wall of the second oblique beam, and a plurality of fourth grooves are formed inwardly on the right side wall of the second oblique beam. The third grooves and the fourth grooves are alternately arranged to form the second serpentine elastic structure.

5. The pressure calculation method according to claim 4, characterized in that: The final deformation amount of the fiber Bragg grating generated when the calculated pressurization platform is subjected to external pressure includes: calculating the bending stiffness of the first serpentine elastic structure or the second serpentine elastic structure; When the pressurizing platform is subjected to external pressure, the first deformation displacement of the optical fiber Bragg grating caused by the external pressure when the first oblique beam and the second oblique beam are tempered is calculated according to the bending stiffness, and the second deformation displacement of the optical fiber Bragg grating caused by the external pressure when the pressurizing platform is tempered is calculated; The first deformation displacement and the second deformation displacement are summed to obtain the final deformation amount of the fiber Bragg grating generated when the pressurizing platform is subjected to the external pressure.

6. The pressure calculation method according to claim 5, characterized in that: Assuming that the first deformation displacement is ΔL'1 and the second deformation displacement is ΔL'2, the calculation formula of the first deformation displacement is: The calculation formula of the second deformation displacement is: Wherein, P is the external pressure, L AB is the length of the pressurized platform, I AB is the moment of inertia of the pressurizing platform; E is Young's modulus; θ is the angle between the first inclined beam and the pressurizing platform or the angle between the second inclined beam and the pressurizing platform, θ is an acute angle; L BC K is the length of the first inclined beam or the second inclined beam; s is the bending stiffness; The calculation formula of the bending stiffness is: Wherein, N is the number of the first groove and the second groove in the first serpentine elastic structure, or the number of the third groove and the fourth groove in the second serpentine elastic structure; S is the moment of inertia of the first serpentine elastic structure or the second serpentine elastic structure; l0 is the width of the first groove or the second groove or the third groove or the fourth groove; l p is the depth of the first groove, the second groove, the third groove, or the fourth groove.

7. The pressure calculation method according to claim 6, characterized in that: The step of calculating the sensitivity enhancement coefficient generated by the first serpentine elastic structure and the second serpentine elastic structure according to the final deformation amount includes: Calculate the final average strain of the fiber Bragg grating when considering the strain influence of the first serpentine elastic structure and the second serpentine elastic structure according to the final deformation amount Said Wherein, L is the length of the fiber Bragg grating between the first oblique beam and the second oblique beam before deformation; Calculating the original deformation of the fiber Bragg grating when the strain influence of the first serpentine elastic structure and the second serpentine elastic structure is not considered, and calculating the original average strain of the fiber Bragg grating corresponding to the original deformation The sensitivity increase coefficient α generated by the first serpentine elastic structure and the second serpentine elastic structure is calculated according to the sensitivity increase coefficient calculation formula, and the sensitivity increase coefficient calculation formula is:

8. The pressure calculation method according to claim 7, characterized in that: The calculating of the original deformation amount of the fiber Bragg grating without considering the strain influence of the first serpentine elastic structure and the second serpentine elastic structure comprises: When the pressurizing platform is subjected to the external pressure, the third deformation displacement of the optical fiber Bragg grating caused by the external pressure after the first oblique beam and the second oblique beam are tempered is calculated without considering the strain influence of the first serpentine elastic structure and the second serpentine elastic structure, and the fourth deformation displacement of the optical fiber Bragg grating caused by the external pressure after the pressurizing platform is tempered is calculated; The third deformation displacement and the fourth deformation displacement are summed to obtain the original deformation amount of the fiber grating.

9. The pressure calculation method according to claim 8, characterized in that: Assuming the third deformation displacement is ΔL1, the fourth deformation displacement is ΔL2, the calculation formula of the third deformation displacement is: The calculation formula of the fourth deformation displacement is: Among them, I BC is the moment of inertia of the first oblique beam or the second oblique beam.

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