阅读说明：本技术 一种小型弹性板结构的光纤光栅加速度传感器及其测量方法 (A kind of optical fibre grating acceleration sensor and its measurement method of the hardened structure of mini elastic ) 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弹性板结构的光纤光栅加速度传感器及其测量方法,包括上盖、底座,连接上盖和底座的上下支柱,位于中部的弹性体和若干光纤光栅,所述弹性体包括质量块和连接在质量块中部两侧的弹性板,上支柱顶部和下支柱底部分别开设有光纤槽A和光纤槽C,质量块的上下表面开设有光纤槽B,两根光纤通过一定预应力依次固定在质量块与上下支柱的光纤槽中,光栅处于支柱与质量块的空隙中,测量时通过建立起加速度与光纤光栅波长漂移量之间的关系,借助解调仪得到光纤光栅中心波长变化,获得振动信号的振动信息。本发明具有结构简单、体积小、成本低、抗电磁干扰、还具有温度补偿,以及便于分布式测量等优点。(The present invention provides the optical fibre grating acceleration sensor and its measurement method of a kind of hardened structure of mini elastic, including upper cover, pedestal, connect the upper lower supporting rod of upper cover and pedestal, elastomer and several fiber gratings positioned at middle part, the elastomer includes mass block and the elastic plate for being connected to mass block on both sides of the middle, at the top of upper supporting column and lower supporting rod bottom offers optical fiber duct A and optical fiber duct C respectively, the upper and lower surface of mass block offers optical fiber duct B, two optical fiber are sequentially fixed in the optical fiber duct of mass block and upper lower supporting rod by certain prestressing force, grating is in the gap of pillar and mass block, by setting up the relationship between acceleration and optic fiber grating wavelength drift value when measurement, fiber bragg grating center wavelength variation is obtained by (FBG) demodulator, obtain the vibration information of vibration signal.The present invention is simple with structure, small in size, at low cost, electromagnetism interference, also has many advantages, such as temperature-compensating, and is convenient for distributed measurement.)

1. a kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic, including upper cover, pedestal, connection upper cover and pedestal Upper lower supporting rod, elastomer and several fiber gratings positioned at middle part, it is characterised in that: the elastomer includes mass block and connection In the elastic plate of mass block on both sides of the middle, elastic plate outer ledge is arranged between upper lower supporting rod, is clamped by upper lower supporting rod solid Fixed, at the top of upper supporting column and lower supporting rod bottom offers optical fiber duct A and optical fiber duct C respectively, and the upper and lower surface of mass block offers light Fine slot B, two optical fiber are sequentially fixed in the optical fiber duct of mass block and upper lower supporting rod by certain prestressing force, and grating is in pillar It in the gap of mass block, is engraved on upper and lower two optical fiber, is floated by setting up acceleration and optic fiber grating wavelength when measurement Relationship between shifting amount obtains fiber bragg grating center wavelength variation by (FBG) demodulator, obtains the vibration information of vibration signal.

2. a kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic as described in claim 1, it is characterised in that: institute It states elastomer to be an integral molding structure, be made using 304 stainless steel materials, be rectangular cylindrical mass block, rectangle in the middle part of elastomer Column block middle section two sides are symmetrically arranged with a pair of of sheet Rectangular Elastic plate.

3. a kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic as described in claim 1, it is characterised in that: institute It states upper cover bottom both ends and is symmetrically arranged with a pair of of upper supporting column, base top both ends are symmetrically arranged with a pair of of lower supporting rod, lower supporting rod on two sides It is respectively cooperating with connection, upper supporting column bottom is equipped with the groove opened up at the top of boss and lower supporting rod and matches, and elastic plate outer end edges are set In lower supporting rod upper groove, it is fixed by upper lower supporting rod.

4. a kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic as described in claim 1, it is characterised in that: institute The line trend for stating the optical fiber duct A opened up on the upper supporting column of two sides, the line trend of the optical fiber duct C opened up on the lower supporting rod of two sides, with The trend of two optical fiber duct B above and below mass block is consistent, and at intervals, for fixing two optical fiber respectively In the optical fiber duct of mass block and upper lower supporting rod, temperature-compensating is realized.

5. a kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic as described in claim 1, it is characterised in that: institute It states between upper supporting column and upper cover, is connected by screw to fixation between lower supporting rod and pedestal and between upper lower supporting rod.

6. a kind of measurement of the optical fibre grating acceleration sensor of the hardened structure of mini elastic as described in any one in claim 1-5 Method, which is characterized in that comprise the following processes: when measurement, sensor is mounted on measured body surface, its pedestal is kept to be in water Prosposition is set, when measured body generate along the vibration of sensor vertical direction when, inertia force effect under, mass block move up and down so that The elastic plate amount of being deformed is led to so that the fiber grating connecting with mass block stretches or compress and obtain the drift of central wavelength It crosses and establishes the correlation of active force suffered by mass block, elastic plate and fiber grating and obtain vibration acceleration and fiber grating strain Relationship, and then the relationship between acceleration and optic fiber grating wavelength drift value is set up, to obtain the vibration letter of acceleration Number.

Technical field

The invention belongs to mechanical oscillation field of measuring technique, and in particular to a kind of fiber grating of the hardened structure of mini elastic adds Velocity sensor and its measurement method.

Background technique

Optical fibre grating acceleration sensor because its with dynamic range the advantages such as wide, high temperature resistant, electromagnetism interference due to it is extensive Detection of the ground for vibration, optical fibre grating acceleration sensor using principle of inertia come sense accelerations signal, and by acceleration Variation be converted into the drift value of fiber bragg grating center wavelength.Stress deformation situation according to grating can be by optical fibre grating acceleration Sensor divides two classes, and fiber grating is pasted onto for the elastic constructions such as cylinder, diaphragm, beam in passing as elastic element by one kind The adhesive type optical fibre grating acceleration sensor that the surface of elastic element is formed, such sensor bulk and quality is larger, Yi Fa Raw chirp phenomenon, another kind are that fiber grating itself is used as elastomer, and sensors with auxiliary electrode stability is poor, easy generations intersection is gone here and there Disturb, the service life it is low.Therefore, in order to which multimetering is installed and detected, be easy in small space, realizes distant signal transmission, The present invention proposes the optical fibre grating acceleration sensor and its measurement method for counting a kind of hardened structure of mini elastic, and the sensor is not only The interference that oscillation crosswise measures longitudinal acceleration can be reduced, have structure is simple, small in size, at low cost, electromagnetism interference, Also have many advantages, such as temperature-compensating, and is convenient for distributed measurement.

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:

A kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic, including upper cover, pedestal connect upper cover and pedestal Upper lower supporting rod, elastomer and several fiber gratings positioned at middle part, it is characterised in that: the elastomer includes mass block and company The elastic plate in mass block on both sides of the middle is connect, elastic plate outer ledge is arranged between upper lower supporting rod, clamps by upper lower supporting rod Fixed, at the top of upper supporting column and lower supporting rod bottom offers optical fiber duct A and optical fiber duct C respectively, and the upper and lower surface of mass block offers Optical fiber duct B, two optical fiber are sequentially fixed in the optical fiber duct of mass block and upper lower supporting rod by certain prestressing force, and grating is in branch It in the gap of column and mass block, is engraved on upper and lower two optical fiber, by setting up acceleration and optic fiber grating wavelength when measurement Relationship between drift value obtains fiber bragg grating center wavelength variation by (FBG) demodulator, obtains the vibration information of vibration signal.

The elastomer is an integral molding structure, and is made using 304 stainless steel materials, is rectangular cylindrical matter in the middle part of elastomer Gauge block, rectangular column block middle section two sides are symmetrically arranged with a pair of of sheet Rectangular Elastic plate.

Upper cover bottom both ends are symmetrically arranged with a pair of of upper supporting column, and base top both ends are symmetrically arranged with a pair of of lower supporting rod, and two Lower supporting rod is respectively cooperating with connection on side, and upper supporting column bottom is equipped with the groove opened up at the top of boss and lower supporting rod and matches, elastic plate Outer end edges are located in lower supporting rod upper groove, are fixed by upper lower supporting rod.

The company of the line trend of the optical fiber duct A opened up on the two sides upper supporting column, the optical fiber duct C opened up on the lower supporting rod of two sides Line trend, it is consistent with the trend of two optical fiber duct B for being located at mass block or more, and at intervals, it is used for two light Fibre is separately fixed in the optical fiber duct of mass block and upper lower supporting rod, realizes temperature-compensating.

Between the upper supporting column and upper cover, it is connected by screw between lower supporting rod and pedestal and between upper lower supporting rod It is fixed.

A kind of measurement method of the optical fibre grating acceleration sensor of the hardened structure of mini elastic, which is characterized in that including such as Lower process: when measurement, being mounted on measured body surface for sensor, its pedestal kept to be in a horizontal position, when measured body generates edge When the vibration of sensor vertical direction, under inertia force effect, mass block moves up and down so that the elastic plate amount of being deformed, so that The fiber grating that is connect with mass block stretch or compression and obtain the drift of central wavelength, by establish mass block, elastic plate and The correlation of active force suffered by fiber grating obtains the relationship of vibration acceleration and fiber grating strain, and then sets up acceleration Relationship between degree and optic fiber grating wavelength drift value, to obtain the vibration signal of acceleration.

The present invention has the advantage that

The present invention can reduce the interference that oscillation crosswise measures longitudinal acceleration using elastic plate as elastic element.This hair It is bright to have many advantages, such as simple structure, small in size, at low cost, electromagnetism interference, also there is temperature-compensating；Be conducive to distributed (more Point) measurement.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of inventive sensor；

Fig. 2 is the structural schematic diagram of upper supporting column in sensor；

Fig. 3 is sensor elastomer structural schematic diagram；

Fig. 4 is the schematic diagram of No. 1 grating #1FBG stress deformation；

Fig. 5 is sensor elastomer-fiber grating equivalent stiffness simplified schematic diagram；

Fig. 6 is the structural schematic diagram of lower supporting rod in sensor；

In figure: 1- upper cover；2- screw；3- upper supporting column；4- elastomer；5- lower supporting rod；6- pedestal；7- optical fiber；8- grating；9- Glue；3-1 boss；3-2 threaded hole；3-3 optical fiber duct A；4-1. elastic plate；4-2. mass block；4-3 optical fiber duct B；5-1 groove；5-2 Threaded hole；5-3 optical fiber duct C

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 6, a kind of optical fibre grating acceleration sensor of the hardened structure of mini elastic, including upper cover 1, pedestal 6, connect upper cover and pedestal Upper lower supporting rod, elastomer 4 and several fiber gratings positioned at middle part, elastomer 4 includes mass block 4-2 and being connected to mass block The elastic plate 4-1 of on both sides of the middle, elastic plate 4-1 outer ledge are arranged between upper lower supporting rod, are fixedly clamped by upper lower supporting rod, 3 top of upper supporting column and 5 bottom of lower supporting rod offer optical fiber duct A3-3 and optical fiber duct C5-3, the upper and lower surface of mass block 4-2 respectively Optical fiber duct B4-3 is offered, two optical fiber 7 are sequentially fixed in the optical fiber duct of mass block and upper lower supporting rod by certain prestressing force, Grating 8 is in the gap of pillar and mass block 4-2, is engraved on upper and lower two optical fiber, by setting up acceleration when measurement With the relationship between optic fiber grating wavelength drift value, fiber bragg grating center wavelength variation is obtained by (FBG) demodulator, obtains vibration letter Number vibration information.

Elastomer is an integral molding structure, and is made using 304 stainless steel materials, is rectangular cylindrical mass block in the middle part of elastomer 4-2, rectangular column block middle section two sides are symmetrically arranged with a pair of of sheet Rectangular Elastic plate 4-1.

1 bottom both ends of upper cover are symmetrically arranged with a pair of of upper supporting column 3, and 6 top both ends of pedestal are symmetrically arranged with a pair of of lower supporting rod 5, and two Lower supporting rod is respectively cooperating with connection on side, and 3 bottom of upper supporting column is equipped with the groove 5-1 opened up at the top of boss 3-1 and lower supporting rod and matches, Elastic plate 4-1 outer end edges are located in lower supporting rod upper groove, are fixed by upper lower supporting rod.

The optical fiber duct C5-3 that the line of the optical fiber duct A3-3 opened up on two sides upper supporting column 3 is moved towards, opened up on two sides lower supporting rod 5 Line trend, it is consistent with the trend of two optical fiber duct B4-3 of mass block 4-2 or more is located at, and at intervals, use It is separately fixed in the optical fiber duct of mass block and upper lower supporting rod in by two optical fiber, realizes temperature-compensating.

Between upper supporting column and upper cover, fixation is connected by screw between lower supporting rod and pedestal and between upper lower supporting rod.

A kind of measurement method of the optical fibre grating acceleration sensor of the hardened structure of mini elastic, comprises the following processes: measurement When, sensor is mounted on measured body surface, its pedestal is kept to be in a horizontal position, when measured body generation is square vertically along sensor To vibration when, under inertia force effect, mass block 4-2 is moved up and down so that the elastic plate 4-1 amount of being deformed, so that and quality The fiber grating 8 of block 4-2 connection stretches or compresses and obtain the drift of central wavelength, by establishing mass block, elastic plate and light The correlation of active force suffered by fine grating obtains the relationship of vibration acceleration and fiber grating strain, and then sets up acceleration With the relationship between optic fiber grating wavelength drift value, to obtain the vibration signal of acceleration.

Measuring principle of the invention is as follows:

When testee vibrates, excitation of the sensor by the vibration acceleration a of vertical direction, mass block is used Property power ma under the action of make elastic plate generate deformation so that mass block descend minute movement in the vertical direction, when being tested When the frequency of object vibration is in the operating frequency range of sensor, mass block caused by the vibration acceleration a of object under test Displacement, the i.e. expression formula of the deflection of elastic plate are as follows:

Wherein, Δ y is the deflection of elastic plate or the displacement of mass block；A is the acceleration of object under test；w_nTo pass The intrinsic frequency of sensor.

As shown in Figure 1, the grating of top 1 is that #1FBG, the grating #2FBG of lower section 2 are symmetrically arranged at the upper and lower of elastomer Side, according to the symmetry of structure, for sensor when the vibration acceleration by vertical direction motivates, two optical fiber terminals are transversely Displacement it is identical and equal with the displacement of mass block.Using #1FBG as analysis object, #1FBG stress deformation figure such as Fig. 4 Shown, in static state, the vertical displacement and optical fiber of fixed point to two fixed endpoint of optical fiber of optical fiber and mass block generate strain Between relationship are as follows:

Wherein, l is horizontal distance of optical fiber one end fixed point to optical fiber and the fixed point of mass block；y₀For optical fiber and quality Vertical displacement of the fixed point of block to two fixed endpoint of optical fiber；ε₀To be made in transducer dwell by applying certain prestressing force The initial strain that optical fiber generates.

By the axial rigidity of optical fiber it is found that in the sensor rigidity of optical fiber expression formula are as follows:

Wherein, E_fFor the Young's modulus of optical fiber, A_fFor the cross-sectional area of optical fiber.

By (2) formula it is found that in dynamic, the vertical displacement of the fixed point of optical fiber and mass block to two fixed endpoint of optical fiber with Optical fiber generates the relationship between strain are as follows:

Simultaneous (2), (4) formula, when the vibration acceleration by vertical direction motivates, optical fiber midpoint is generated along light sensor Relationship between fine lateral displacement variable and strain are as follows:

Wherein, Δ y be optical fiber and mass block fixed point to two fixed endpoint of optical fiber vertical displacement variable quantity；y₁For The sensor vertical displacement of the fixed point of optical fiber and mass block to two fixed endpoint of optical fiber in dynamic；ε₁It is sensor in dynamic When dependent variable of optical fiber when being in a horizontal position relative to optical fiber.

Simultaneous (1), (5) formula, expression formula are as follows:

From (6) formula it is found that being non-linear between the sensor vibration acceleration a being subject to and the axial strain variable quantity of optical fiber , but be that linearly, can be obtained according to Taylor's formula, vibration acceleration a and fiber axis between the two in lesser vibration section Relational expression between strain variation amount are as follows:

Wherein, Δ ε₁For sensor when being vibrated acceleration excitation optical fiber along its axial strain variation amount.

According to optical fiber sensor mechanism it is found that fiber grating wavelength shift and strain, temperature change relationship are as follows:

Wherein, λ is the middle cardiac wave of fiber grating；Δ λ is the wavelength shift of fiber grating；p_eFor the bullet spectrum of optical fiber Number, α_fThermal expansion coefficient, ξ for optical fiber_fIt is temperature change for thermo-optical coeffecient, the Δ t of optical fiber.

By (8) Shi Ke get, when sensor is when the vibration acceleration by vertical direction motivates, #1FBG central wavelength becomes Expression formula between change amount and its strain variation amount are as follows:

Wherein, λ₁For the middle cardiac wave of fiber grating；Δλ₁For the wavelength shift of fiber grating.

When sensor by vertical direction vibration acceleration motivate when, the change in displacement situation phase of #1FBG and #2FBG Instead, i.e. when #1FBG is stretched, #2FBG is shunk, then the strain variation amount that #1FBG and #2FBG are generated is on the contrary, then Δ ε₁=-Δ ε₂。

Similarly, for #2FBG, the relational expression of fiber optic hub wavelength variable quantity and strain variation amount are as follows:

Wherein, λ₂For the middle cardiac wave of fiber grating；Δλ₂For the wavelength shift of fiber grating.Due to λ₁≈λ₂> > Δ λ₁、Δλ₂, simultaneous (9), (10) formula have:

Simultaneous (7), (11) Shi Ke get:

As shown in Figure 5, the global stiffness of sensor are as follows:

K=2k_f+2k_b (13)

Wherein, k_bFor the rigidity of elastic plate, expression formula are as follows:

Wherein, E is the elasticity modulus of spring plate material；B is the width of elastic plate；H is the thickness of elastic plate；l_bFor elasticity The length of plate.

By (13), (14) Shi Ke get, the intrinsic frequency of sensor are as follows:

Wherein, m is the quality of mass block.

Simultaneous (12), (15) Shi Ke get:

The variation of testee acceleration can be obtained by the wavelength shift of two fiber gratings according to formula (16) formula, from And obtain vibration signal.

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.