阅读说明：本技术 一种小型化具有温度补偿的光纤光栅加速度传感器及其测量方法 (A kind of miniaturization has the optical fibre grating acceleration sensor and its measurement method of temperature-compensating ) 是由 魏莉 姜达洲 余玲玲 李恒春 于 2019-08-14 设计创作，主要内容包括：本发明提供一种小型化具有温度补偿的光纤光栅加速度传感器及其测量方法,包括上壳、下壳,位于上下壳之间的质量块,质量块两侧对称设置有两块矩形弹性板,质量块中部开设有螺纹孔,用于与螺杆连接,螺杆底部连接弹性主体,所述弹性主体包括两侧柱状外壁,柱状外壁之间设有一对支柱和位于中部的连接块,外壁与支柱之间、支柱与连接块之间均通过铰链连接,螺杆底部穿过弹性主体中部的连接块,弹性主体的两个支柱下表面均开设有光纤槽,弹性主体两侧外壁底部开设有光纤槽,传感器内设置有两根光纤。本发明传感器结构简单,体积小,频率高；具有体积小、耐高温、可在小空间内工作、可实现分布式检测等优点。(The present invention provides a kind of optical fibre grating acceleration sensor and its measurement method of the miniaturization with temperature-compensating, including upper casing, lower casing, mass block between upper lower casing, mass block two sides are symmetrically arranged with two blocks of Rectangular Elastic plates, threaded hole is offered in the middle part of mass block, for being connect with screw rod, screw rod bottom connects elastic body, the elastic body includes two sides cylindrical outer wall, a pair of posts and the link block positioned at middle part are equipped between cylindrical outer wall, between outer wall and pillar, it is connected by a hinge between pillar and link block, screw rod bottom passes through the link block in the middle part of elastic body, two pillar lower surfaces of elastic body offer optical fiber duct, elastic body two sides outer wall bottom offers optical fiber duct, two optical fiber are provided in sensor.Inventive sensor structure is simple, small in size, and frequency is high；Have many advantages, such as small in size, high temperature resistant, can work in small space, Distributed Detection can be achieved.)

1. the optical fibre grating acceleration sensor that a kind of miniaturization has temperature-compensating, it is characterised in that: including upper casing, lower casing, Mass block between upper lower casing, mass block two sides are symmetrically arranged with two blocks of Rectangular Elastic plates, offer spiral shell in the middle part of mass block Pit, for connect with screw rod, screw rod bottom connection elastic body, the elastic body includes two sides cylindrical outer wall, outside column It is equipped with a pair of posts and the link block positioned at middle part between wall, between outer wall and pillar, passes through hinge between pillar and link block Chain link, screw rod bottom pass through the link block in the middle part of elastic body, and two pillar lower surfaces of elastic body offer optical fiber Slot, elastic body two sides outer wall bottom offer optical fiber duct, and two optical fiber are provided in sensor, and two optical fiber wherein lead to for one It crosses prestressing force to be fixed in two posts bottom optical fiber ducts, No. 1 grating-#1FBG is carved on the optical fiber, another optical fiber one end is fixed In the column bottom optical fiber duct of side, the other end is drawn out of outer wall bottom light slot, and No. 2 grating-# are carved on the optical fiber 2FBG obtains the drift value of fiber bragg grating center wavelength by demodulated equipment to obtain vibration acceleration information and environment temperature Variation.

2. a kind of miniaturization as described in claim 1 has the optical fibre grating acceleration sensor of temperature-compensating, feature exists In: the upper casing is downward opening U-shaped frame, is cooperatively connected at the top of U-shaped frame both ends bottom and elastic body two sides outer wall, quality The Rectangular Elastic plate outer edge of block two sides is fixed between upper casing and outer wall.

3. a kind of miniaturization as described in claim 1 has the optical fibre grating acceleration sensor of temperature-compensating, feature exists In: the hinge be block narrow in the middle and wide at both ends, by four hinges by two outer walls, two pillars and a link block according to It is secondary to link together.

4. a kind of miniaturization as described in any one of claims 1-3 has the optical fibre grating acceleration sensor of temperature-compensating Measurement method, which comprises the steps of:

Step S1, when measuring, the lower casing of sensor is fixed on testee, keeps the bottom surface of lower cover and the surface of object under test It is installed together, keeps the bottom surface holding of sensor horizontal, when testee generates vibration, mass block Z under the action of inertia Axis moves up and down, and is deformed elastic plate, and the deflection of elastic plate is passed to the link block in elastic body by screw rod, So that link block is also moved up and down along Z axis, when link block moves up and down, two pillars are around hinge along Y-axis opposite direction Small rotation is generated, so that the #1FBG being fixed on pillar obtains the drift of central wavelength；Variation of ambient temperature causes # The drift of 2FBG central wavelength；

Step S2, the relational model between testee acceleration and #1FBG wavelength shift is established；Establish variation of ambient temperature With the relational model of #2FBG wavelength shift.

5. the measurement side that a kind of miniaturization as claimed in claim 4 has the optical fibre grating acceleration sensor of temperature-compensating Method, which is characterized in that the specific steps of the step S2 are as follows:

Step S21: under the action of inertia, mass block will generate inertia force m straight down₂a_Z, the inertia force make elastic plate and Link block in elastic body generates identical displacement, releases the constraint that mass block is subject to, and the sensor-based system is used in mass block Property power, optical fiber active force and hinge restoring force effect under, according to reach bright BELL'S THEOREM, mechanical balance equation are as follows:

F=F₁+F₂=m₂a_Z (2)

In above formula, F₁、F₂Respectively elastic plate, link block are to the active force of mass block；m₁、m₂Respectively single pillar, mass block Quality；a_ZFor Z-direction vibration acceleration；δl₁、δl₂、Δl_fThe respectively position of pillar, mass block and optical fiber fixed point one end Shifting amount；k_fFor optical fiber axial direction stiffness coefficient；k₁For hinge rotational stiffness；β is the torsion angle of hinge；

Within the scope of certain vibrational excitation, the torsion angle β of hinge is smaller, then pillar, mass block and optical fiber fixed point one end Displacement expression formula is respectively as follows:

l₁=(R+c₁/2)β (3)

l₂=(c₁+2R)β (4)

In formula, R is the cut radius of hinge；c₁For the length of pillar；h₁It is hinge with the height of lower supporting rod；l_fIt is solid for optical fiber two The distance of fixed end point；α is fixed point and angle of the hinge center of rotation connecting line in Z-direction, b on the inside of optical fiber₁For the width of pillar； c₂、b₂、h₂The respectively length of mass block, width, height；It is assumed that ρ₁、ρ₂The respectively density of material of pillar and mass block, matter Amount expression formula is respectively as follows:

m₁=ρ₁(2R+t+h₁)c₁b₁ (6)

m₂=ρ₂(c₂b₂h₂) (7)

The distance of two fixed endpoint of optical fiber are as follows: l_f=2R+c₄ (8)

In formula, c₄For the length of link block, optical fiber is considered as here as a spring, in conjunction with optical fiber axial direction stiffness coefficient with The relationship of two fixed endpoint distance of fiber grating, rigidity expression formula are as follows:

In formula, E_fFiber-draw elasticity modulus；A_fFor cross section of optic fibre area；

R, b, t are respectively the cut radius, width, thickness of hinge arrangement；Hinge as an important component in elastic body, When mass block passes motion to link block by screw rod, link block is moved up and down so that two pillars are small around hinge generation Rotation, so that the fiber grating being pasted onto pillar optical fiber duct generates axial deflection, so the rotation of hinge arrangement Rigidity k₁Be influence sensor performance important parameter the rotational stiffness of hinge is acquired, i.e., according to the empirical equation of hinge stiffness

In formula, q_mFor the central angle of hinge；E is the elasticity modulus of flexible hinge material；f₂For intermediate variable, expression formula are as follows:

Wherein, i=R/t；

Be conducive to reduce lateral vibration interference, rigidity expression formula using Rectangular Elastic plate are as follows:

In formula, E₁For the elasticity modulus of Rectangular Elastic plate material；l₅、b₅、h₅The respectively length of Rectangular Elastic plate, width, height； The elastic plate of mass block two sides, which can be considered, to be connected in parallel, and the global stiffness of elastic plate is 2k₂；

Simultaneous above formula, the small torsion angle β of hinge are as follows:

The horizontal displacement Δ l of optical fiber fixed point one end on pillar_fAre as follows:

If the spacing of optical fiber fixed endpoint is l on two pillars_f, the width of rectangular flexible beam is b, and the axial direction of No.1 grating #1FBG is answered Become Δ ε₁Are as follows:

Step S22: according to the strain of fiber grating, temperature sensing mechanism, the central wavelength drift value and strain and temperature of #1FBG Relationship are as follows:

In formula, λ₁For the central wavelength for applying No. 1 grating after certain prestressing force；Δλ₁It drifts about for the central wavelength of fiber grating Amount；Δε₁For the dependent variable of fiber grating；p_eFor the elasto-optical coefficient of optical fiber；α_fFor the thermal expansion coefficient of optical fiber；ξ_fFor the heat of optical fiber Backscatter extinction logarithmic ratio；Δ t is the temperature variation of working sensor environment；

Similarly, the central wavelength drift value of #2FBG and the relationship of temperature are as follows:

Simultaneous above formula, available #1FBG central wavelength drift value Δ λ ' because of caused by vibration₁With its strain Δε₁Relationship Formula:

Step S23: the sensitivity S of sensor Z-direction is obtained according to the expression formula of step S21 and step S22_ZAre as follows:

Step S24: acceleration of the testee along Z-direction can be obtained according to the expression formula of step 22 and step 23 are as follows:

The acceleration vibration signal of testee is obtained by the wavelength shift of fiber grating.

Technical field

The invention belongs to mechanical oscillation field of measuring technique, and in particular to a kind of miniaturization has the optical fiber light of temperature-compensating Grid acceleration transducer and its measurement method.

Background technique

In recent years, extensive development and utilization that fiber-optic grating sensor at home and abroad obtains, in national defence, national economy The vibration measurement in equal fields is more and more extensive.Vibrating sensor can characterize vibration signal with vibration acceleration or amplitude, frequency. The method of existing detection vibration can be divided into electro-detection method, light detection method according to the physics mode of detection vibration signal.Electro-detection Method uses electrical measurement acceleration transducer, perceives vibration acceleration using mass block, elastic element and conversion element.The type The main condenser type again of acceleration, piezoelectric type, three kinds induction.But electro-detection method is easy the interference, unfavorable by electromagnetism In remote detection.Optical fibre grating acceleration is because it is with light and handy safety in light detection method, it is easy to accomplish telemetering, anti-electromagnetism are dry It is strong to disturb ability, the advantages such as corrosion-and high-temp-resistant obtain rapid development.Current optical fiber grating vibration acceleration sensor is main Acceleration bring external force is born using structures such as diaphragm, elastic piece, spring beams, leads to the drift of fiber bragg grating center wavelength It moves, obtains the drift value of optic fiber grating wavelength using (FBG) demodulator to measure acceleration.Although with the structures such as spring beam, diaphragm bullet work Low-frequency vibration demand can be met for the acceleration transducer of elastic element；But the dynamic characteristic of this structure is by the rigid of structural body Degree influences, and overall structure size is bigger than normal, is unfavorable for being installed in small space and implements vibration detection；Furthermore most of optical fiber Grating acceleration transducer adds survey while being used only for detection vibration and cannot achieve temperature and vibration.The present invention proposes meter one The optical fibre grating acceleration sensor and its measurement method that kind miniaturization has temperature-compensating are passed for measuring acceleration information Sensor size is small, measurement range is wide, it can be achieved that vibration and many reference amounts of temperature measure.

Summary of the invention

In view of the problems of the existing technology, the technical solution that the present invention uses to solve problems of the prior art It is as follows:

It is a kind of miniaturization have temperature-compensating optical fibre grating acceleration sensor, it is characterised in that: including upper casing, under Shell, the mass block between upper lower casing, mass block two sides are symmetrically arranged with two blocks of Rectangular Elastic plates, offer in the middle part of mass block Threaded hole, for connecting with screw rod, screw rod bottom connects elastic body, and the elastic body includes two sides cylindrical outer wall, column It is equipped with a pair of posts and the link block positioned at middle part between outer wall, passes through between outer wall and pillar, between pillar and link block Hinge connection, screw rod bottom pass through the link block in the middle part of elastic body, and two pillar lower surfaces of elastic body offer light Fine slot, elastic body two sides outer wall bottom offer optical fiber duct, are provided with two optical fiber in sensor, and two optical fiber wherein one It is fixed in two posts bottom optical fiber ducts by prestressing force, No. 1 grating-#1FBG is carved on the optical fiber, another optical fiber one end is solid It is scheduled in the column bottom optical fiber duct of side, the other end is drawn out of outer wall bottom light slot, and No. 2 grating-# are carved on the optical fiber 2FBG obtains the drift value of fiber bragg grating center wavelength by demodulated equipment to obtain vibration acceleration information and environment temperature Variation.

The upper casing is downward opening U-shaped frame, and cooperation connects at the top of U-shaped frame both ends bottom and elastic body two sides outer wall It connects, the Rectangular Elastic plate outer edge of mass block two sides is fixed between upper casing and outer wall.

The hinge is block narrow in the middle and wide at both ends, by four hinges by two outer walls, two pillars and a company Block is connect to be connected in turn.

A kind of measurement method of optical fibre grating acceleration sensor of the miniaturization with temperature-compensating, which is characterized in that packet Include following steps:

Step S1, when measuring, the lower casing of sensor is fixed on testee, keeps bottom surface and the object under test of lower cover Be surface mounted in makes the bottom surface holding of sensor horizontal together, when testee generates vibration, effect of the mass block in inertia Lower Z axis moves up and down, and is deformed elastic plate, and the deflection of elastic plate is passed to the connection in elastic body by screw rod Block, so that link block is also moved up and down along Z axis, when link block moves up and down, two pillars are around hinge along Y-axis phase negative side To small rotation is generated, so that the #1FBG being fixed on pillar obtains the drift of central wavelength；Variation of ambient temperature causes # The drift of 2FBG central wavelength；

Step S2, the relational model between testee acceleration and #1FBG wavelength shift is established；Establish environment temperature The relational model of variation and #2FBG wavelength shift.

The specific steps of the step S2 are as follows:

Step S21: under the action of inertia, mass block will generate inertia force m straight down₂a_Z, which makes elastic plate And the link block in elastic body generates identical displacement, releases the constraint that mass block is subject to, the sensor-based system is in quality Under block inertia force, optical fiber active force and the effect of hinge restoring force, foundation reaches bright BELL'S THEOREM, mechanical balance equation are as follows:

F=F₁+F₂=m₂a_Z (2)

In above formula, F₁、F₂Respectively elastic plate, link block are to the active force of mass block；m₁、m₂Respectively single pillar, matter The quality of gauge block；a_ZFor Z-direction vibration acceleration；δl₁、δl₂、Δl_fRespectively pillar, mass block and optical fiber fixed point one end Displacement；k_fFor optical fiber axial direction stiffness coefficient；k₁For hinge rotational stiffness；β is the torsion angle of hinge；

Within the scope of certain vibrational excitation, the torsion angle β of hinge is smaller, then pillar, mass block and optical fiber fixed point one The displacement expression formula at end is respectively as follows:

l₁=(R+c₁/2)β (3)

l₂=(c₁+2R)β (4)

In formula, R is the cut radius of hinge；c₁For the length of pillar；h₁It is hinge with the height of lower supporting rod；l_fFor optical fiber The distance of two fixed endpoints；α is fixed point and angle of the hinge center of rotation connecting line in Z-direction, b on the inside of optical fiber₁For pillar Width；c₂、b₂、h₂The respectively length of mass block, width, height；It is assumed that ρ₁、ρ₂The material of respectively pillar and mass block is close Degree, quality expression formula are respectively as follows:

m₁=ρ₁(2R+t+h₁)c₁b₁ (6)

m₂=ρ₂(c₂b₂h₂) (7)

The distance of two fixed endpoint of optical fiber are as follows: l_f=2R+c₄ (8)

In formula, c₄For the length of link block, optical fiber is considered as here as a spring, in conjunction with optical fiber axial direction rigidity system Several relationships with two fixed endpoint distance of fiber grating, rigidity expression formula are as follows:

In formula, E_fFiber-draw elasticity modulus；A_fFor cross section of optic fibre area；

R, b, t are respectively the cut radius, width, thickness of hinge arrangement；Hinge is important as one in elastic body Component, when mass block passes motion to link block by screw rod, link block is moved up and down so that two pillars are produced around hinge Raw minor rotation, so that the fiber grating being pasted onto pillar optical fiber duct generates axial deflection, so hinge arrangement Rotational stiffness k₁Be influence sensor performance important parameter the rotation of hinge is acquired according to the empirical equation of hinge stiffness Rigidity, i.e.,

In formula, q_mFor the central angle of hinge；E is the elasticity modulus of flexible hinge material；f₂For intermediate variable, expression formula Are as follows:

Wherein, i=R/t；

Be conducive to reduce lateral vibration interference, rigidity expression formula using Rectangular Elastic plate are as follows:

In formula, E₁For the elasticity modulus of Rectangular Elastic plate material；l₅、b₅、h₅Respectively the length of Rectangular Elastic plate, width, Highly；The elastic plate of mass block two sides, which can be considered, to be connected in parallel, and the global stiffness of elastic plate is 2k₂；

Simultaneous above formula, the small torsion angle β of hinge are as follows:

The horizontal displacement Δ l of optical fiber fixed point one end on pillar_fAre as follows:

If the spacing of optical fiber fixed endpoint is l on two pillars_f, the width of rectangular flexible beam is b, No.1 grating #1FBG's Axial strain Δ ε₁Are as follows:

Step S22: according to the strain of fiber grating, temperature sensing mechanism, the central wavelength drift value of #1FBG and strain and The relationship of temperature are as follows:

In formula, λ₁For the central wavelength for applying No. 1 grating after certain prestressing force；Δλ₁For the central wavelength of fiber grating Drift value；Δε₁For the dependent variable of fiber grating；p_eFor the elasto-optical coefficient of optical fiber；α_fFor the thermal expansion coefficient of optical fiber；ξ_fFor optical fiber Thermo-optical coeffecient；Δ t is the temperature variation of working sensor environment；

Similarly, the central wavelength drift value of #2FBG and the relationship of temperature are as follows:

Simultaneous above formula, available #1FBG central wavelength drift value Δ λ ' because of caused by vibration₁With its strain Δε₁'s Relational expression:

Step S23: the sensitivity S of sensor Z-direction is obtained according to the expression formula of step S21 and step S22_ZAre as follows:

Step S24: acceleration of the testee along Z-direction can be obtained according to the expression formula of step 22 and step 23 are as follows:

The acceleration vibration signal of testee is obtained by the wavelength shift of fiber grating.

The present invention has the advantage that

Inventive sensor structure is simple, small in size, and frequency is high；Set up acceleration and long-period fiber grating wavelength amount Between relationship, the wavelength change by measuring fiber grating can be obtained the acceleration information of vibration signal；Using rectangle bullet Property plate makes working sensor more stable；Using elastic body as elastic element, it can be achieved that vibrating with temperature many reference amounts simultaneously Detection；Have many advantages, such as small in size, high temperature resistant, can work in small space, Distributed Detection can be achieved.

Detailed description of the invention

Fig. 1 is inventive sensor structural perspective；

Fig. 2 is the elastic plate and mass block integral structure figure of inventive sensor；

Fig. 3 is the perspective view of the elastic body of inventive sensor；

Fig. 4 is rectangular flexible beam-mass block-elastic body stress deformation schematic diagram of inventive sensor；

In figure: 1. upper casings；2. mass block；3. screw rod；4. elastic body；5. optical fiber；6. lower casing；7. No.1 grating (# 1FBG)；8. No. two gratings (#2FBG), 9. colloids；3-1 link block；3-2. outer wall；3-3. hinge；3-4. pillar.

Specific embodiment

Below with reference to the embodiments and with reference to the accompanying drawing the technical solutions of the present invention will be further described, such as Fig. 1- Shown in 4, a kind of miniaturization has the optical fibre grating acceleration sensor of temperature-compensating, it is characterised in that: including upper casing 1, lower casing 6, the mass block 2 between upper lower casing, mass block two sides are symmetrically arranged with two blocks of Rectangular Elastic plates, open up in the middle part of mass block 2 There is threaded hole, for connecting with screw rod 3, screw rod bottom connects elastic body 4, and the elastic body 4 includes two sides cylindrical outer wall 3-2 is equipped with a pair of posts 3-4 and link block 3-1 positioned at middle part between cylindrical outer wall, between outer wall and pillar, pillar and company It connects and is connected by hinge 3-3 between block, 3 bottom of screw rod passes through the link block in the middle part of elastic body, two branch of elastic body Column lower surface offers optical fiber duct, and elastic body two sides outer wall bottom offers optical fiber duct, and two light are provided in sensor Fibre, two optical fiber are wherein fixed in two posts bottom optical fiber ducts for one by prestressing force, and No. 1 grating (# is carved on the optical fiber 1FBG) 7, another optical fiber one end is fixed in the column bottom optical fiber duct of side, and the other end is drawn out of outer wall bottom light slot, No. 2 gratings (#2FBG) 8 are carved on the optical fiber,

Upper casing 1 is downward opening U-shaped frame, is cooperatively connected at the top of U-shaped frame both ends bottom and elastic body two sides outer wall, matter The Rectangular Elastic plate outer edge of gauge block two sides is fixed between upper casing and outer wall.

Mass block 2 is integrated with Rectangular Elastic plate, and threaded hole is had among mass block, for being connect with screw rod 3, Mass block 2 moves up and down under effect of inertia along Z axis so that elastic plate generates micro-strain；

Mass block 2 is fixedly connected by screw rod 3 by helicitic texture with the connector in elastic body 4, while can be by bullet Property plate deflection pass to pillar in elastic body so that pillar free end generate along Y-axis displacement；

Hinge 3-3 is block narrow in the middle and wide at both ends, is connected two outer walls, two pillars and one by four hinges Block is connected in turn.

A kind of measurement method of optical fibre grating acceleration sensor of the miniaturization with temperature-compensating, which is characterized in that packet Include following steps: when step S1, measuring, the lower casing of sensor is fixed on testee, keeps bottom surface and the determinand of lower cover Being surface mounted in for body makes the bottom surface holding of sensor horizontal together, and when testee generates vibration, mass block is in inertia It acts on lower Z axis to move up and down, is deformed elastic plate, is passed to the deflection of elastic plate in elastic body by screw rod Link block, so that link block is also moved up and down along Z axis, when link block moves up and down, two pillars are around hinge along Y-axis phase Opposite direction generates small rotation, so that the #1FBG being fixed on pillar obtains the drift of central wavelength；Variation of ambient temperature is drawn Play the drift of #2FBG central wavelength；

Step S2, the relational model between testee acceleration and #1FBG wavelength shift is established；Establish environment temperature The relational model of variation and #2FBG wavelength shift.

The specific steps of the step S2 are as follows:

Step S21: under the action of inertia, mass block will generate inertia force m straight down₂a_Z, which makes elastic plate And the link block in elastic body generates identical displacement, releases the constraint that mass block is subject to, the sensor-based system is in quality Under block inertia force, optical fiber active force and the effect of hinge restoring force, foundation reaches bright BELL'S THEOREM, mechanical balance equation are as follows:

F=F₁+F₂=m₂a_Z (2)

In above formula, F₁、F₂Respectively elastic plate, link block are to the active force of mass block；m₁、m₂Respectively single pillar, matter The quality of gauge block；a_ZFor Z-direction vibration acceleration；δl₁、δl₂、Δl_fRespectively pillar, mass block and optical fiber fixed point one end Displacement；k_fFor optical fiber axial direction stiffness coefficient；k₁For hinge rotational stiffness；β is the torsion angle of hinge；

Within the scope of certain vibrational excitation, the torsion angle β of hinge is smaller, then pillar, mass block and optical fiber fixed point one The displacement expression formula at end is respectively as follows:

l₁=(R+c₁/2)β (3)

l₂=(c₁+2R)β (4)

In formula, R is the cut radius of hinge；c₁For the length of pillar；h₁It is hinge with the height of lower supporting rod；l_fFor optical fiber The distance of two fixed endpoints；α is fixed point and angle of the hinge center of rotation connecting line in Z-direction, b on the inside of optical fiber₁For pillar Width；c₂、b₂、h₂The respectively length of mass block, width, height；It is assumed that ρ₁、ρ₂The material of respectively pillar and mass block is close Degree, quality expression formula are respectively as follows:

m₁=ρ₁(2R+t+h₁)c₁b₁ (6)

m₂=ρ₂(c₂b₂h₂) (7)

The distance of two fixed endpoint of optical fiber are as follows: l_f=2R+c₄ (8)

In formula, c₄For the length of link block, optical fiber is considered as here as a spring, in conjunction with optical fiber axial direction rigidity system Several relationships with two fixed endpoint distance of fiber grating, rigidity expression formula are as follows:

In formula, E_fFiber-draw elasticity modulus；A_fFor cross section of optic fibre area；

R, b, t are respectively the cut radius, width, thickness of hinge arrangement；Hinge is important as one in elastic body Component, when mass block passes motion to link block by screw rod, link block is moved up and down so that two pillars are produced around hinge Raw minor rotation, so that the fiber grating being pasted onto pillar optical fiber duct generates axial deflection, so hinge arrangement Rotational stiffness k₁Be influence sensor performance important parameter the rotation of hinge is acquired according to the empirical equation of hinge stiffness Rigidity, i.e.,

In formula, q_mFor the central angle of hinge；E is the elasticity modulus of flexible hinge material；f₂For intermediate variable, expression formula Are as follows:

Wherein, i=R/t；

Be conducive to reduce lateral vibration interference, rigidity expression formula using Rectangular Elastic plate are as follows:

In formula, E₁For the elasticity modulus of Rectangular Elastic plate material；l₅、b₅、h₅Respectively the length of Rectangular Elastic plate, width, Highly；The elastic plate of mass block two sides, which can be considered, to be connected in parallel, and the global stiffness of elastic plate is 2k₂；

Simultaneous above formula, the small torsion angle β of hinge are as follows:

The horizontal displacement Δ l of optical fiber fixed point one end on pillar_fAre as follows:

If the spacing of optical fiber fixed endpoint is l on two pillars_f, the width of rectangular flexible beam is b, No.1 grating #1FBG's Axial strain Δ ε₁Are as follows:

Step S22: according to the strain of fiber grating, temperature sensing mechanism, the central wavelength drift value of #1FBG and strain and The relationship of temperature are as follows:

In formula, λ₁For the central wavelength for applying No. 1 grating after certain prestressing force；Δλ₁For the central wavelength of fiber grating Drift value；Δε₁For the dependent variable of fiber grating；p_eFor the elasto-optical coefficient of optical fiber；α_fFor the thermal expansion coefficient of optical fiber；ξ_fFor optical fiber Thermo-optical coeffecient；Δ t is the temperature variation of working sensor environment；

Similarly, the central wavelength drift value of #2FBG and the relationship of temperature are as follows:

Simultaneous above formula, available #1FBG central wavelength drift value Δ λ ' because of caused by vibration₁With its strain Δε₁'s Relational expression:

Step S23: the sensitivity S of sensor Z-direction is obtained according to the expression formula of step S21 and step S22_ZAre as follows:

Step S24: acceleration of the testee along Z-direction can be obtained according to the expression formula of step 22 and step 23 are as follows:

The acceleration vibration signal of testee is obtained by the wavelength shift of fiber grating.

Protection scope of the present invention is not limited to the above embodiments, it is clear that those skilled in the art can be to this hair It is bright to carry out various changes and deformation without departing from scope and spirit of the present invention.If these changes and deformation belong to power of the present invention In the range of benefit requirement and its equivalent technologies, then including the intent of the present invention also includes these changes and deforms.