CN104374330A - Sensor temperature compensation device - Google Patents

Abstract

The invention provides a sensor temperature compensation device which comprises a measuring rod, a reference rod, a working sensor and a comparison sensor. The working sensor is arranged on the measuring rod and the comparison sensor is arranged on the reference rod. The working sensor is used for measuring the structural stress strain and the temperature stress strain of the measuring rod and the temperature stress strain of the working sensor. The comparison sensor is used for measuring the temperature stress strain of the reference rod and the temperature stress strain of the comparison sensor. The same sensors are adopted as the working sensor and the comparison sensor. The measuring rod and the reference rod are made of the same materials. The measuring rod is used for bearing loads. The reference rod is adjacent to the measuring rod and does not bear loads. The sensor temperature compensation device is simple in structure and capable of simply and effectively achieving temperature compensation of the rods.

Description

Sensor Temperature Compensation device

Technical field

The present invention relates to ocean engineering technology, particularly, relate to a kind of Sensor Temperature Compensation device.

Background technology

Sensor is widely used in various industrial practice, and the sensitive element of most of sensor adopts metal or semiconductor material, and its static characteristic and environment temperature have close contacting.Operating ambient temperature due to sensor in real work changes greatly, the thermal output caused due to temperature variation is again larger, larger measuring error will be brought, so must take measures to reduce or eliminate the impact that temperature variation brings, namely must carry out temperature compensation.

In order to eliminate or reduce the impact of temperature variation, there has been proposed many compensation schemes.By consulting the data of Optical Fiber Strain Gauge temperature compensation aspect, the method for existing temperature compensation is broadly divided into two classes.

One class is that strain temperature is measured simultaneously, is got rid of the interference of temperature strain, as matrix operation method by computing.Matrix operation method is at the grating of fibre core sensing section overlap write two different center wavelength variation, utilizes their different temperatures sensitivity coefficient and gage factor, tries to achieve suffered stress and temperature variation by matrix operation.Method based on this theory has many kinds, and as Dual-wavelength Overlapping method, long-period gratings method, diameter is identical and fiber grating burning-on method etc. that core material is different, measures while all can realizing strain and temperature.The weak point of these class methods is: require that the difference of the centre wavelength of two fiber gratings is enough large, often need two cover wideband light source and Wavelength demodulation systems, limitation is very large in actual applications.

Another kind of is take temperature compensation measure, encapsulates as utilized minus thermal-expansion coefficient.Utilize minus thermal-expansion coefficient packaged fiber grating, because temperature variation causes grating to stretch, and encapsulating material is the change oppositely experiencing temperature, can offset the effect of expanding with heat and contract with cold of grating, keeps grating indeformable, reaches the object of temperature compensation.The weak point of these class methods is: reversal deformation coefficient requirements encapsulating material being experienced to temperature variation is very high, not only will meet the requirements of scope but also also must be stabilized in certain limit along with this coefficient of changes in environmental conditions, this proposes excessive demand to material undoubtedly.

Summary of the invention

For defect of the prior art, the object of this invention is to provide a kind of Sensor Temperature Compensation device.

According to Sensor Temperature Compensation device provided by the invention, comprise and measure rod member and with reference to rod member, also comprise working sensor and contrast sensor;

Wherein, described working sensor is arranged on described measurement rod member, and described contrast sensor setting is on described reference rod member;

Described working sensor for measure rod member structural stress strain, measure rod member temperature stress strain and working sensor temperature stress strain; Described contrast sensor is used for the temperature stress strain of witness mark rod member and the temperature strain of contrast sensor;

Described working sensor and described contrast sensor adopt identical sensor; Described measurement rod member and described reference rod member adopt identical material to make; Described measurement rod member is used for bearing load; Described with reference to the adjacent described measurement rod member of rod member and not bearing load.

Preferably, the interface position of described working sensor and described contrast sensor adopts laser bonding, and the pad of interface position adopts sacrificial protection.

Preferably, the active section of described working sensor and described contrast sensor adopts sylphon seal welding.

Preferably, the first base and the second base is also comprised;

Described working sensor is welded on described measurement rod member by described first base; Described contrast sensor is welded on described with reference on rod member by described second base.

Preferably, described working sensor and described contrast sensor all adopt fibre optic strain sensor.

Preferably, the first screw and the second screw is also comprised; Described first screw is used for described working sensor Shi Hanzhang, and described second screw is used for described contrast sensor Shi Hanzhang.

Preferably, also comprise fiber metal tube, described fiber metal tube is arranged along the length direction of described measurement rod member, and the optical fiber of described working sensor and the optical fiber of described contrast sensor draw the water surface by described fiber metal tube.

Preferably, described first base and described second base adopt elastic construction.

Preferably, also comprise Teflon sleeve pipe, described Teflon sleeve pipe is arranged on the outside of described fiber metal tube.

Preferably, also comprise walking wire fixing clip, the optical fiber of described working sensor and described contrast sensor is fixedly fastened on described measurement rod member by described cabling.

Compared with prior art, the present invention has following beneficial effect:

1, instant invention overcomes the shortcoming adopting minus thermal-expansion coefficient encapsulation grating, do not need the negative expansion coefficient of strict control of material, substantially reduce the difficulty of material selection;

2, structure of the present invention is simple, comparatively simple and effectively can realize the temperature compensation of measuring rod member;

3, the present invention is provided with away wire fixing clip, and optical fiber cabling is convenient, can be fixed on rod member like a cork;

4, the present invention enormously simplify matrix operation method, can find out that the present invention is a larger improvement to first kind temperature compensation, effectively rejects temperature impact, and do not need employing two to overlap wideband light source and Wavelength demodulation system with contrast Fibre Optical Sensor.

Accompanying drawing explanation

By reading the detailed description done non-limiting example with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:

Fig. 1 is the scheme of installation of sensor in the present invention;

Fig. 2 is the schematic layout pattern of sensor in the present invention;

Fig. 3 is the fixing schematic diagram of sensor in the present invention.

In figure:

1 is pillar;

2 is diagonal brace rod member;

3 is platform deck;

4 is hardstand;

5 is installation site;

6 is contrast sensor;

7 is working sensor;

8 is platform welding limit leg;

9 is fiber metal tube;

10 is corrugated tube;

11 is screw.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art and understand the present invention further, but not limit the present invention in any form.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, some distortion and improvement can also be made.These all belong to protection scope of the present invention.

For field of ocean engineering, many employings are to humidity and have the insensitive silica fibre strain transducer of the environment of water.By to Bragg center reflection wavelength λ for its sensing ultimate principle of Fibre Optical Sensor _bthe measurement of drift realizes the measurement to strain, temperature variation, and analysis can know that Bragg wave length shift and strain, temperature relation are:

$\frac{\mathrm{\Δ\λ}}{{\mathrm{\λ}}_B}=(1-p_e)\mathrm{\Δ\ϵ}+(\mathrm{\α}+\mathrm{\ξ})\mathrm{\ΔT}$

In formula, λ _bfor Bragg wavelength; Δ λ is Bragg wavelength variable quantity; n _efffor fibre core effective refractive index;

for the valid elastic-optic constants of optical fiber; P ₁₁and P ₁₂for elasto-optical coefficient, v is the Poisson ratio of optical fiber core material; The axial strain of Δ ε suffered by foil gauge; Δ T is the variable quantity of temperature; α and ξ is respectively thermal expansivity and the thermo-optical coeffecient of optical fiber;

Above formula also can be written as:

$\frac{\mathrm{\Δ\λ}}{{\mathrm{\λ}}_B}=K_{\mathrm{\ϵ}}\mathrm{\Δ\ϵ}+K_T\mathrm{\ΔT}$

In formula, Κ _εfor the ga(u)ge factor of fiber grating, Κ _tfor temperature control coefficient.Because fiber grating cannot distinguish the wavelength variations straining and cause respectively with temperature, the cross sensitivity problem of strain and temperature therefore can be brought in the measurements.In addition, known through consulting reference materials: conventional silica fibre p _e=0.22, α=0.55 × 10 ^-6/ DEG C, ξ=6.8 × 10 ^-6/ DEG C, and temperature and strain are to Κ _εand Κ _timpact very little, can ignore.Then fiber grating respectively under temperature variation 1 DEG C and axial strain 1 μ ε effect both ratio be

$\frac{\frac{{\mathrm{\Δ\λ}}_1}{{\mathrm{\λ}}_B}}{\frac{{\mathrm{\Δ\λ}}_2}{{\mathrm{\λ}}_B}}=\frac{K_T\mathrm{\ΔT}}{K_{\mathrm{\ϵ}}\mathrm{\Δ\ϵ}}=\frac{(\mathrm{\α}+\mathrm{\ξ})\mathrm{\ΔT}}{(1-P_e)\mathrm{\Δ\ϵ}}=\frac{(6.8+0.55)\×{10}^{-6}}{(1-0.22)\×{10}^{-6}}=9.423$

This illustrates that per unit value temperature is 9.42 times of microstrain on the impact that Bragg centre wavelength is drifted about, and therefore, when making strain sensing with fiber grating and measuring, must consider the impact of how to remove temperature.

Be employing two Fibre Optical Sensors for the problems referred to above ultimate principle of the present invention, one of them is working sensor, and another is contrast sensor, can be obtained the strain value of required material by the comparing calculation of two sensor measurement data.The more important thing is that this kind of method also comparatively simply can realize the temperature compensation to Steel material.

By above formula:

$\frac{\mathrm{\Δ\λ}}{{\mathrm{\λ}}_B}=K_{\mathrm{\ϵ}}\mathrm{\Δ\ϵ}+K_T\mathrm{\ΔT}$

Can find intuitively, record the impact of temperature variation on wavelength variations if want, as long as make strain Δε=0 of optical fiber, then formula becomes:

$\frac{\mathrm{\Δ\λ}}{{\mathrm{\λ}}_B}=K_T\mathrm{\ΔT}---\left(1\right)$

As long as therefore allow contrast sensor answer vanishing, then the wavelength variations measured by this sensor is all caused by temperature variation, namely has:

$\frac{{\mathrm{\Δ\λ}}_1}{{\mathrm{\λ}}_B}=K_{\mathrm{\ϵ}}\mathrm{\Δ\ϵ}+K_T\mathrm{\ΔT}$

$\frac{{\mathrm{\Δ\λ}}_2}{{\mathrm{\λ}}_B}=K_T\mathrm{\ΔT}$

Wherein: Δ λ ₁with Δ λ ₂be respectively the wavelength variations that working sensor records with contrast sensor.Two formulas are subtracted each other and can be obtained:

$\frac{{\mathrm{\Δ\λ}}_1-{\mathrm{\Δ\λ}}_2}{{\mathrm{\λ}}_B{K}_{\mathrm{\ϵ}}}=\mathrm{\Δ\ϵ}---\left(2\right)$

This formula can obtain the strain of the material that will know.

Again the method is done further in-depth, contrast sensor is pasted onto one section freely on Steel material, then the change of the wavelength of contrast measured by sensor is jointly caused by the temperature variation of Steel material and optical fiber, supposes that the ess-strain of Steel material and temperature strain are respectively Δ ε and Δ ε ₁, then have:

$\frac{{\mathrm{\Δ\λ}}_1}{{\mathrm{\λ}}_B}=K_{\mathrm{\ϵ}}(\mathrm{\Δ\ϵ}+{\mathrm{\Δ\ϵ}}_1)+K_T\mathrm{\ΔT}$

$\frac{{\mathrm{\Δ\λ}}_2}{{\mathrm{\λ}}_B}=K_{\mathrm{\ϵ}}{\mathrm{\Δ\ϵ}}_1+K_T\mathrm{\ΔT}$

Wherein: Δ λ ₁with Δ λ ₂be respectively the wavelength variations that working sensor records with contrast sensor.Two formulas are subtracted each other and can be obtained:

$\frac{{\mathrm{\Δ\λ}}_1-{\mathrm{\Δ\λ}}_2}{{\mathrm{\λ}}_B{K}_{\mathrm{\ϵ}}}=\mathrm{\Δ\ϵ}---\left(3\right)$

Contrast (2) and formula (3) can find, two formulas are identical, therefore adopt this kind of method can by two kinds of temperature strain full remunerations.

In the present embodiment, Sensor Temperature Compensation device provided by the invention comprises measures rod member and reference rod member, measures rod member and adopts Steel material to make with reference to rod member, also comprise working sensor 6 and contrast sensor 7;

Wherein, described working sensor 7 is arranged on described measurement rod member, the diagonal brace rod member 2 namely in Fig. 1, and described contrast sensor 6 is arranged on described with reference on rod member;

Described working sensor 7 for measure rod member structural stress strain, measure rod member temperature stress strain and working sensor temperature stress strain; The temperature stress strain of described contrast sensor 6 for witness mark rod member and the temperature strain of contrast sensor; Described working sensor 7 and described contrast sensor 6 adopt identical sensor; Described measurement rod member and described reference rod member adopt identical material to make; Described measurement rod member is used for bearing load; Described with reference to the adjacent described measurement rod member of rod member and not bearing load.Namely strain value is obtained by the comparing calculation of two sensor measurement data.Wherein, the change of the wavelength measured by working sensor is jointly caused by the temperature variation of Steel material microstrain, Steel material temperature variation, optical fiber, and the change of the wavelength of contrast measured by sensor is caused by the temperature variation of Steel material temperature variation, optical fiber.

For ensureing sensor body sealing, the interface position of described working sensor 7 and described contrast sensor 6 adopts laser bonding, and the pad of interface position adopts sacrificial protection.For not increasing sensor body rigidity, the active section of described working sensor 7 and described contrast sensor 6 adopts corrugated tube 10 seal welding.

Sensor Temperature Compensation device provided by the invention also comprises the first base and the second base; Described working sensor by described first base Underwater Welding on described measurement rod member; Described contrast sensor passes through described second base Underwater Welding described with reference on rod member.Described working sensor and described contrast sensor all adopt fibre optic strain sensor.Described first base and described second base adopt elastic construction.All add except leg 9 position, platform welding limit and do preservative treatment, at surface spraying Teflon.

Sensor Temperature Compensation device provided by the invention also comprises the first screw and the second screw; Described first screw is used for described working sensor Shi Hanzhang, and described second screw is used for described contrast sensor Shi Hanzhang.

Sensor Temperature Compensation device provided by the invention also comprises fiber metal tube 9, described fiber metal tube 9 is arranged along the length direction of described measurement rod member, and the optical fiber of described working sensor and the optical fiber of described contrast sensor draw the water surface by described fiber metal tube 9.In order to ensure reliability and the security of monitoring, optical fiber is along measuring rod member cabling, and sensor is separate not to be connected in series under water, all causes after more than the water surface carry out networking connection until all the sensors two ends stern fast.

Sensor Temperature Compensation device provided by the invention also comprises Teflon sleeve pipe, and described Teflon sleeve pipe is arranged on the outside of described fiber metal tube 9.Sensor Temperature Compensation device provided by the invention also comprises walking wire fixing clip, and the optical fiber of described working sensor and described contrast sensor is fixedly fastened on described measurement rod member by described cabling.

Owing to not detecting absolute stress suffered by rod member after sensor installation, the variable quantity of stress can only be detected, therefore determine that initial stress values is extremely important.By selecting when a right up and down little year condition in Practical Project, being determined the stress intensity of each check point by numerical evaluation, and measured value is demarcated.Why selected without wave little year condition, reason is without unrestrained environmental stress not in fluctuation change, and stress is less, and calibrated error is also less.

Above specific embodiments of the invention are described.It is to be appreciated that the present invention is not limited to above-mentioned particular implementation, those skilled in the art can make various distortion or amendment within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims (10)

1. a Sensor Temperature Compensation device, comprises and measures rod member and with reference to rod member, it is characterized in that, also comprises working sensor and contrast sensor;

Wherein, described working sensor is arranged on described measurement rod member, and described contrast sensor setting is on described reference rod member;

Described working sensor for measure rod member structural stress strain, measure rod member temperature stress strain and working sensor temperature stress strain; Described contrast sensor is used for the temperature stress strain of witness mark rod member and the temperature strain of contrast sensor;

Described working sensor and described contrast sensor adopt identical sensor; Described measurement rod member and described reference rod member adopt identical material to make; Described measurement rod member is used for bearing load; Described with reference to the adjacent described measurement rod member of rod member and not bearing load.

2. Sensor Temperature Compensation device according to claim 1, is characterized in that, the interface position of described working sensor and described contrast sensor adopts laser bonding, and the pad of interface position adopts sacrificial protection.

3. Sensor Temperature Compensation device according to claim 1, is characterized in that, the active section of described working sensor and described contrast sensor adopts sylphon seal welding.

4. Sensor Temperature Compensation device according to claim 1, is characterized in that, also comprises the first base and the second base;

Described working sensor is welded on described measurement rod member by described first base; Described contrast sensor is welded on described with reference on rod member by described second base.

5. Sensor Temperature Compensation device according to claim 1, is characterized in that, described working sensor and described contrast sensor all adopt fibre optic strain sensor.

6. Sensor Temperature Compensation device according to claim 1, is characterized in that, also comprises the first screw and the second screw; Described first screw is used for described working sensor Shi Hanzhang, and described second screw is used for described contrast sensor Shi Hanzhang.

7. Sensor Temperature Compensation device according to claim 1, it is characterized in that, also comprise fiber metal tube, described fiber metal tube is arranged along the length direction of described measurement rod member, and the optical fiber of described working sensor and the optical fiber of described contrast sensor draw the water surface by described fiber metal tube.

8. Sensor Temperature Compensation device according to claim 4, is characterized in that, described first base and described second base adopt elastic construction.

9. Sensor Temperature Compensation device according to claim 7, is characterized in that, also comprises Teflon sleeve pipe, and described Teflon sleeve pipe is arranged on the outside of described fiber metal tube.

10. the Sensor Temperature Compensation device according to claim 1 or 7, is characterized in that, also comprise walking wire fixing clip, and the optical fiber of described working sensor and described contrast sensor is fixedly fastened on described measurement rod member by described cabling.