CN102749035A - Optical-fiber grating displacement transducer and sensing method - Google Patents

Abstract

The invention provides an optical-fiber grating displacement sensing method, the sensing method comprises the following steps that (A1) when a displacement occurs outside, an inclined plane is pushed to move by a detector, and a combination of information on corresponding positions of contacts on at least two strain beams and the inclined plane changes, so as to enable at least two optical-fiber gratings respectively connected with the strain beams to be strained; and (A2) the combination of the strain of the at least two optical-fiber gratings and the information on corresponding positions is analyzed, so as to obtain outside displacements corresponding to different sensitivities. The sensing method has the advantages of large measuring range, high sensibility and the like.

Description

Fiber grating displacement sensor and method for sensing

Technical field

The present invention relates to the measurement of displacement, particularly fiber grating displacement sensor and method for sensing.

Background technology

Optical fiber is when small stretching, and the wavelength of Fiber Bragg Grating FBG (hereinafter to be referred as grating) and the small displacement of stretching are linear.The fiber grating slit gauge promptly is through certain device, and this micro-displacement of linear amplification is realized the measurement to the big displacement in outside.

Fig. 1 has schematically provided the schematic diagram of slit gauge in the prior art; As shown in Figure 1, when the external world has displacement, during the action of the pull bar pull of slit gauge; Be connected the top of going up that the inclined-plane then can cause feeler lever with pull bar; The top can cause the variation of grating strain beam deflection again on the feeler lever, and the variation of this amount of deflection then can be passed to grating, makes grating that the wavelength change of measuring take place.But amount of deflection little in the grating strain beam elastic range changes approximately linear, and the slit gauge of this structure promptly through the linear transformation of inclined-plane-amount of deflection, is realized the measurement of the big displacement of pull bar.Range is the horizontal length on inclined-plane, and sensitivity is the ratio of feeler lever grating wavelength difference and range when being in inclined-plane bottom, top.

Since the material of optical fiber own, in elastic range, the amount of tension of grating very little (being that wavelength variable quantity is very little).In the practical application, be not damaged in order to protect grating, the wavelength change of grating generally is controlled at about 4nm in the slit gauge.At present, the slit gauge in the optical fiber industry all adopts the monochromatic light grid to carry out displacement measurement, has many deficiencies, as:

1, range one timing of slit gauge, sensitivity is the 4nm/ range to the maximum, can't improve again;

When 2, keeping the sensitivity of maximum, can't improve range;

3, in each range interval, sensitivity is constant, does not have multistage sensitivity.

Summary of the invention

In order to solve the deficiency in the above-mentioned prior art scheme, the invention provides big, highly sensitive fiber grating displacement sensor of a kind of range and method.

The objective of the invention is to realize through following technical scheme:

Fiber grating displacement sensor, said displacement transducer comprises:

At least two fiber gratings, an end of said fiber grating is fixed, and the other end is installed in respectively on the different strain beams;

At least two strain beams, an end of said strain beam is fixed, and has the contact element that contacts with the inclined-plane on the strain beam;

The inclined-plane; In difference constantly, the combination of the positional information of contact element on the inclined-plane at least two strain beams has difference; When the external world had displacement, said contact element had on said inclined-plane and relatively moves, and the said strain beam that strain takes place makes said fiber grating produce strain;

Probe, said probe is connected with said inclined-plane;

Analysis module, said analysis module obtains extraneous displacement according to the combination of the strain of said fiber grating.

According to above-mentioned displacement transducer, alternatively, said inclined-plane is one, and the contact element of said at least two strain beams divides the time to be located on said inclined-plane, perhaps is in respectively on the differing heights on said inclined-plane.

According to above-mentioned displacement transducer, alternatively, said inclined-plane is two or more, and the contact element of said at least two strain beams can relatively move on one or more inclined-planes respectively.

According to above-mentioned displacement transducer, alternatively,, only there is a contact element to be on the inclined-plane at synchronization, perhaps different contact elements is in respectively on the different inclined-planes.

According to above-mentioned displacement transducer, alternatively, said inclined-plane is plane or curved surface.

According to above-mentioned displacement transducer, alternatively, said analysis module is used for knowing the residing range of extraneous displacement, sensitivity interval according to the combination of the strain of said fiber grating.

The object of the invention also is achieved by the following technical programs:

The fiber grating displacement method for sensing, said method for sensing may further comprise the steps:

When (A1) external world had displacement, probe promoted the inclined-plane motion, and the contact element at least two strain beams changes with the combination of the relative position information on said inclined-plane, thus feasible at least two fiber grating generation strains that are connected with strain beam respectively;

(A2) analyze the combination of the strain of said at least two fiber gratings, thereby know extraneous displacement.

According to above-mentioned method for sensing, alternatively, the analytical approach that said step (A2) adopts is:

(B1) combination according to said relative position information draws the residing range of extraneous displacement interval;

(B2) extraneous displacement is known in the influence to light wavelength, the said interval that cause according to the strain of said fiber grating.

According to above-mentioned method for sensing, alternatively, in the process that relatively moves of inclined-plane and contact element, at least two contact elements divide the time to be located on the inclined-plane, or are in simultaneously on the different inclined-planes.

According to above-mentioned method for sensing, alternatively, in the process of relatively moving, contact element relatively moves on an inclined-plane at least.

According to above-mentioned method for sensing, alternatively, said inclined-plane is plane or curved surface.

Compared with prior art, the beneficial effect that has of the present invention is:

1, under the certain situation of range, (exponentially) improved the sensitivity of displacement transducer, and different structural forms can improve different multiples;

2, in range ability, can be with the sensitivity segmentation, the sensitivity that different range sections is corresponding different;

3, under the certain situation of sensitivity, improve the range of displacement transducer.

Description of drawings

With reference to accompanying drawing, disclosure of the present invention will be easier to understand.Those skilled in the art are understood that easily: these accompanying drawings only are used to illustrate technical scheme of the present invention, and are not to be intended to protection scope of the present invention is constituted restriction.Among the figure:

Fig. 1 is the basic block diagram according to slit gauge in the prior art;

Fig. 2 is the basic block diagram according to the displacement transducer of the embodiment of the invention 1,2;

Fig. 3 is the process flow diagram according to the displacement sensing method of the embodiment of the invention 1;

Fig. 4 is the basic block diagram according to the displacement transducer of the embodiment of the invention 3;

Fig. 5 is the basic block diagram according to the displacement transducer of the embodiment of the invention 4;

Fig. 6 is the basic block diagram according to the displacement transducer of the embodiment of the invention 4;

Fig. 7 is the basic block diagram according to the displacement transducer of the embodiment of the invention 5;

Fig. 8 is the basic block diagram according to the displacement transducer of the embodiment of the invention 6;

Fig. 9 is the basic block diagram according to the displacement transducer of the embodiment of the invention 7;

Figure 10 is the basic block diagram according to the displacement transducer of the embodiment of the invention 8.

Embodiment

Fig. 2-10 and following declarative description optional embodiment of the present invention how to implement with instruction those skilled in the art and reproduce the present invention.In order to instruct technical scheme of the present invention, simplified or omitted some conventional aspects.Those skilled in the art should understand that the modification or the replacement that are derived from these embodiments will be within the scope of the invention.Those skilled in the art should understand that following characteristics can make up to form a plurality of modification of the present invention in every way.Thus, the present invention is not limited to following optional embodiment, and is only limited claim and their equivalent.

Embodiment 1:

Fig. 2 has schematically provided the basic block diagram of the fiber grating displacement sensor of the embodiment of the invention.As shown in Figure 2, said sensor comprises:

At least two fiber gratings, like Bragg grating, an end of said fiber grating is fixed, and the other end is installed in respectively on the different strain beams;

At least two strain beams, an end of said strain beam is fixed, and has the contact element that contacts with the inclined-plane on the strain beam; The initial position of at least one contact element is in the bottom on inclined-plane; Said strain beam is the state of the art, repeats no more at this.

The inclined-plane; In difference constantly; The combination of the positional information of contact element on the inclined-plane at least two strain beams has difference; It is different with the relative position on inclined-plane also to be that said contact element is in, as: the differing heights place on same inclined-plane, or a part of contact element is in, and another part is on the plane on the inclined-plane; Or the equal height place on different inclined-planes, or the differing heights place on different inclined-planes; When the external world had displacement, said contact element had on said inclined-plane and relatively moves, and the said strain beam that strain takes place makes said fiber grating produce strain;

Probe, said probe is connected with said inclined-plane;

Analysis module, said analysis module obtains extraneous displacement according to the combination of the strain of said fiber grating, the sensitivity that this displacement is corresponding certain.

Certainly, said sensor also comprises light source, shunt and spectrometer, and the light that light source sends gets into optical fiber through a road of shunt; Through fiber grating the time; Part light is reflected by former road, through being received by spectrometer behind the shunt, can obtain the wavelength change of fiber grating.These devices and concrete connected mode are the prior aries of understanding easily for those skilled in the art, repeat no more at this.

Fig. 3 has schematically provided the process flow diagram of the fiber grating displacement method for sensing of the embodiment of the invention.As shown in Figure 3, said method for sensing may further comprise the steps:

When (A1) external world had displacement, probe promoted the inclined-plane motion, and the combination of the contact element at least two strain beams and the relative position information on said inclined-plane changes; It is different with the relative position on inclined-plane also to be that said contact element is in, as: the differing heights place on same inclined-plane, or a part of contact element is in, and another part is on the plane on the inclined-plane; Or the equal height place on different inclined-planes, or the differing heights place on different inclined-planes; Thereby make at least two fiber grating generation strains that are connected with strain beam respectively;

(A2) analyze the combination of the strain of said at least two fiber gratings, thereby know extraneous displacement, the sensitivity that this displacement is corresponding certain.

The benefit that reaches according to the embodiment of the invention 1 is: use at least two fiber gratings, making has different wavelengths to change under the situation of same displacement, thereby obtains the different wavelengths varied, also is different sensitivity.

Embodiment 2:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Fig. 2 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 2, first contact element on first strain beam is when the bottom of (only tapered plane) slides into the summit from the inclined-plane, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.Second contact element on second strain beam is when the bottom on inclined-plane slides into the summit, and the wavelength change that is installed in second fiber grating on second strain beam is Δ λ _M2, also be that its maximum wavelength changes.

Above-mentioned first and second contact elements are one in front and one in back to install, and spacing is L, and the length of the orthogonal projection on inclined-plane is a, and the initial position of first contact element is the bottom on inclined-plane.

For above-mentioned slit gauge, range is R=L+a, if R＞2L, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

When 0≤x＜L, also be the range section for [0, L),

y ₂=0, also promptly make up (y ₁, y ₂) in, Only there is first contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\Δ\; Y}}{\mathrm{\Δ\; x}}=\frac{\mathrm{\Δ}(y_1+y_2)}{\mathrm{\Δ\; x}}=\frac{\mathrm{\Δ}{\mathrm{\λ}}_{m1}}{R-L}$

When L≤x≤R-L, also be that the range section is [L, R-L],

Also promptly make up (y ₁, y ₂) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}\&CenterDot;L\&le;y_1\&le;{\mathrm{\&lambda;}}_{m1},$ $0\&le;y_2<\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;(R-2L),$ First and second contact elements all are on the inclined-plane; Sensitivity in this range section is:

When R-L＜x≤R, also be the range section for (R-L, R], y ₁=Δ λ _M1,

Also promptly make up (y ₁, y ₂) in,

Only there is second contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}.$

Expression formula by sensitivity in each range section can be known, can go to change sensitivity through adjusting each parameter, as increasing L to improve sensitivity.

For above-mentioned slit gauge, range is R=L+a, if R=2L, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

When 0≤x≤L, also be that the range section is [0, L],

y ₂=0, also promptly make up (y ₁, y ₂) in, 0≤y ₁≤Δ λ _M1, only have first contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{L}$

When L＜x≤R, also be the range section for (L, R], y ₁=Δ λ _M1,

Also promptly make up (y ₁, y ₂) in, 0＜y ₂≤Δ λ _M2, only have second contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{L}.$

Expression formula by sensitivity in each range section can know that the sensitivity that different range sections are corresponding different also can go to change sensitivity through adjusting each parameter, as reduces L to improve sensitivity.In whole range, synchronization only has a contact element to be on the inclined-plane.

Above-mentioned slit gauge is when work (corresponding to displacement sensing method), and process is:

(A1) record the combination (y of the wavelength change of first, second fiber grating ₁, y ₂) (y ₁Corresponding to the positional information on main deviational survey face of first contact element, y ₂And be sent to analysis module the positional information on auxilliary deviational survey face corresponding to second contact element);

(A2) analysis module is according to above-mentioned wavelength change y ₁, y ₂With the wavelength change that obtains being suitable for and the relational expression of displacement, utilize this relational expression to know displacement x and sensitivity.

The benefit that reaches according to the embodiment of the invention 2 is: use at least two fiber gratings, making has different wavelengths to change under the situation of same displacement, thereby obtains the different wavelengths varied, also is different sensitivity.Compared with prior art, under the identical situation of range, improve sensitivity, also increased the combination of sensitivity; Under the identical situation of sensitivity, improved range.

Embodiment 3:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Fig. 4 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 4, first contact element on first strain beam is when the bottom of (only tapered plane) slides into the summit from the inclined-plane, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.Second contact element on second strain beam is when the bottom on inclined-plane slides into the summit, and the wavelength change that is installed in second fiber grating on second strain beam is Δ λ _M2, also be that its maximum wavelength changes.The 3rd contact element on the 3rd strain beam is when the bottom on inclined-plane slides into the summit, and the wavelength change that is installed in the 3rd fiber grating on the 3rd strain beam is Δ λ _M3, also be that its maximum wavelength changes.

Above-mentioned first, second installed before and after with the 3rd contact element being, spacing is respectively L ₁, L ₂, L=L ₁+ L ₂Length a less than the orthogonal projection on inclined-plane.The initial position of first contact element is in the bottom on inclined-plane.

For above-mentioned slit gauge, range is R=L+a, and R＞2L, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Change y with the 3rd optic fiber grating wavelength ₃Be respectively with the relation of probe displacement x:

As 0≤x≤L ₁The time, also be the range section for [0, L ₁],

y ₂=0, y ₃=0, also promptly make up (y ₁, y ₂, y ₃) in,

Only there is first contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2+y_3)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}$

Work as L ₁During＜x＜L, also be that the range section is (L ₁, L),

y ₃=0, also promptly make up (y ₁, y ₂, y ₃) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}\&CenterDot;L_1<y_1<\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}\&CenterDot;L,$ $0<y_2<\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;L_2,$ First and second contact elements all are on the same inclined-plane; Sensitivity in this range section is:

When L≤x≤R-L, also be that the range section is [L, R-L], $y_1=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}\&CenterDot;x,$ $y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;(x-L_1),$ $y_3=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(x-L),$ Also promptly make up (y ₁, y ₂, y ₃) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}\&CenterDot;L\&le;y_1\&le;\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1},$ $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;L_2<y_2\&le;\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;(R-L-L_1),$ $0\&le;y_3\&le;\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(R-2L),$ First, second all is on the same inclined-plane with the 3rd contact element; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2+y_3)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}$

As R-L＜x＜R-L+L ₁The time, also be that the range section is (R-L, R-L+L ₁), y ₁=Δ λ _M1, $y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;(x-L_1),$ $y_3=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(x-L),$ Also promptly make up (y ₁, y ₂, y ₃) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;(R-L-L_1)<y_2<\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2},$ $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(R-2L)<y_3<\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(R-L-L_2),$ The second and the 3rd contact element is on the inclined-plane; Sensitivity in this range section is:

Work as R-L+L ₁During≤x≤R, also be that the range section is [R-L+L ₁, R], y ₁=Δ λ _M1, y ₂=Δ λ _M2, $y_3=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(x-L),$ Also promptly make up (y ₁, y ₂, y ₃) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(R-L-L_2)\&le;y_3\&le;\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3},$ Only the 3rd contact element is on the inclined-plane; Sensitivity in this range section is:

Expression formula by sensitivity in each range section can know that the sensitivity that different range sections are corresponding different also can go to change sensitivity through adjusting each parameter, as increasing L to improve sensitivity.

Embodiment 4:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Fig. 5 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 5, first contact element on first strain beam is when the bottom on first inclined-plane slides into the summit, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.Second contact element on second strain beam is when the bottom on second inclined-plane slides into the summit, and the wavelength change that is installed in second fiber grating on second strain beam is Δ λ _M2, also be that its maximum wavelength changes.

Above-mentioned first and second contact elements are one in front and one in back to install, and arrange before and after first inclined-plane and second inclined-plane.The initial position of second contact element is in the bottom on inclined-plane.

As shown in Figure 5, for above-mentioned slit gauge, range is R, if first contact element and first inclined-plane equal the length b of the orthogonal projection on second inclined-plane, the wavelength change y of first fiber grating apart from a ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

When 0≤x＜b, also be the range section for [0, b), y ₁=0,

Also promptly make up (y ₁, y ₂) in, 0≤y ₂＜Δ λ _M2, only have second contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}$

When b≤x≤R, also be that the range section is [b, R],

y ₂=Δ λ _M2, also promptly make up (y ₁, y ₂) in, 0≤y ₁≤Δ λ _M1, only there is first contact element to be on the inclined-plane, the sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-b}$

Expression formula by sensitivity in each range section can know that the sensitivity that different range sections are corresponding different also can go to change sensitivity through adjusting each parameter.

As shown in Figure 6, for above-mentioned slit gauge, range is R, if first contact element and first inclined-plane apart from a ₁Orthogonal projection length a with first inclined-plane ₂Sum is less than the length b (R=b) of the orthogonal projection on second inclined-plane, then the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

As 0≤x≤a ₁The time, also be the range section for [0, a ₁], y ₁=0,

Also promptly make up (y ₁, y ₂) in,

Only there is second contact element to be on the inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}$

Work as a ₁＜x＜a ₁+ a ₂The time, also be that the range section is (a ₁, a ₁+ a ₂),

Also promptly make up (y ₁, y ₂) in, 0＜y ₁＜Δ λ _M1,

First contact element and second contact element all are on the inclined-plane; Sensitivity in this range section is:

Work as a ₁+ a ₂During≤x≤b, also be that the range section is [a ₁+ a ₂, b], y ₁=Δ λ _M1,

Also promptly make up (y ₁, y ₂) in,

Only second contact element is on the inclined-plane, and the sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}.$

Expression formula by sensitivity in each range section can be known, the identical sensitivity of different range section counterpart also can go to change sensitivity through adjusting each parameter, as reduces b to improve sensitivity.

Above-mentioned slit gauge is when work (corresponding to displacement sensing method), and process is:

(A1) record the combination (y of the wavelength change of first, second fiber grating ₁, y ₂) (y ₁Corresponding to the positional information on main deviational survey face of first contact element, y ₂And be sent to analysis module the positional information on auxilliary deviational survey face corresponding to second contact element);

(A2) analysis module is according to above-mentioned wavelength change y ₁, y ₂With the wavelength change that obtains being suitable for and the relational expression of displacement, utilize this relational expression to know displacement x and sensitivity.

Embodiment 5:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Fig. 7 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 7, solid line partly is main deviational survey face, has 2 main deviational survey faces, and the angle of wedge on each inclined-plane is different; First contact element on first strain beam is when the bottom of main deviational survey face slides into the summit, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.

Dotted line is auxilliary deviational survey face, and 1 inclined-plane only, second contact element on second strain beam are when the bottom of auxilliary deviational survey face slides into the summit, and the wavelength change that is installed in second fiber grating on second strain beam is Δ λ _M2, also be that its maximum wavelength changes.Above-mentioned first and second contact elements are to install side by side, and initial position all is in the bottom on inclined-plane.

For above-mentioned slit gauge, range is R, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

As 0≤x＜Δ x ₁The time, also be the range section for [0, Δ x ₁),

Also promptly make up (y ₁, y ₂) in, 0≤y ₁＜Δ λ _M1,

First contact element and second contact element all are on the inclined-plane, and the sensitivity in this range section is:

As Δ x ₁During≤x≤R, also be that the range section is [Δ x ₁, R],

Also promptly make up (y ₁, y ₂) in, 0≤y ₁≤Δ λ _M1, First contact element and second contact element all are on the inclined-plane, and the sensitivity in this range section is:

Expression formula by sensitivity in each range section can know that the sensitivity that different range sections are corresponding different also can go to change sensitivity through adjusting each parameter, as reduce Δ x ₁With improve the range section [0, Δ x ₁) interior sensitivity.In whole range, first contact element relatively moves on 2 main deviational survey faces respectively, and second contact element only relatively moves on an auxilliary deviational survey face.

Above-mentioned slit gauge is when work (corresponding to displacement sensing method), and process is:

(A1) record the combination (y of the wavelength change of first, second fiber grating ₁, y ₂) (y ₁Corresponding to the positional information on main deviational survey face of first contact element, y ₂And be sent to analysis module the positional information on auxilliary deviational survey face corresponding to second contact element);

(A2) analysis module is according to above-mentioned wavelength change y ₁, y ₂With the wavelength change that obtains being suitable for and the relational expression of displacement, utilize this relational expression to know displacement x and sensitivity.

Embodiment 6:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Fig. 8 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 8, solid line partly is main deviational survey face, total a main deviational survey face, and the angle of wedge on each inclined-plane is identical; First contact element on first strain beam is when the bottom of main deviational survey face slides into the summit, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.

Dotted line is auxilliary deviational survey face, and when second contact element on second strain beam slided into the summit from the bottom of assisting the deviational survey face, the wavelength change that is installed in second fiber grating on second strain beam was Δ λ _M2, also be that its maximum wavelength changes.Above-mentioned first and second contact elements are to install side by side, and initial position all is in the bottom on inclined-plane.

For above-mentioned slit gauge, range is R, and then second optic fiber grating wavelength changes y ₂With the probe displacement x following relation is arranged:

$y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R}\&CenterDot;x$

When second optic fiber grating wavelength changes y ₂For

The time, the wavelength change y of first fiber grating ₁With the relation of probe displacement x be:

$y_1={(-1)}^{n-1}\frac{\mathrm{a\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R}\&CenterDot;x+\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}\&CenterDot;[\frac{1+{(-1)}^{n-1}}{2}+{(-1)}^n\&CenterDot;n]$

In the following formula, n is a positive integer, represents first contact element to be in from n the main deviational survey face on a left side.

In range section [0; R] in, the sensitivity of slit gauge is:

can go to improve sensitivity through the number a that increases main deviational survey face.In whole range, first contact element relatively moves on a main deviational survey face respectively, and second contact element only relatively moves on an auxilliary deviational survey face.

Above-mentioned slit gauge is when work (corresponding to displacement sensing method), and process is:

(A1) record the combination (y of the wavelength change of first, second fiber grating ₁, y ₂) (y ₁Corresponding to the positional information on main deviational survey face of first contact element, y ₂And be sent to analysis module the positional information on auxilliary deviational survey face corresponding to second contact element);

(A2) analysis module is according to above-mentioned wavelength change y ₂And

Draw n, n is a positive integer, and also promptly this moment, first contact element was in from which main deviational survey face on a left side;

Analysis module is basis again $y_1={(-1)}^{n-1}\frac{\mathrm{A\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R}\&CenterDot;x+\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}\&CenterDot;[\frac{1+{(-1)}^{n-1}}{2}+{(-1)}^n\&CenterDot;n]$ Handle said wavelength change y ₁, n, thereby know displacement x and sensitivity.

Embodiment 7:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Fig. 9 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 9, solid line partly is main deviational survey face, has 2 main deviational survey faces; First contact element on first strain beam is when the bottom of main deviational survey face slides into the summit, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.

Dotted line is auxilliary deviational survey face, has 2 auxilliary deviational survey faces, and when second contact element on second strain beam slided into the summit from the bottom of assisting the deviational survey face, the wavelength change that is installed in second fiber grating on second strain beam was Δ λ _M2, also be that its maximum wavelength changes.Above-mentioned first and second contact elements are to install side by side, and initial position all is in the bottom on inclined-plane.

For above-mentioned slit gauge, range is R, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

As 0≤x＜Δ x ₁The time, also be the range section for [0, Δ x ₁),

Also promptly make up (y ₁, y ₂) in, 0≤y ₁＜Δ λ _M1,

Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{\mathrm{\&Delta;}{x}_1}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{\mathrm{\&Delta;}{x}_2}.$

As Δ x ₁≤x＜Δ x ₂The time, also be that the range section is [Δ x ₁, Δ x ₂),

Also promptly make up (y ₁, y ₂) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-\mathrm{\&Delta;}{x}_1}\&CenterDot;(R-\mathrm{\&Delta;}{x}_2)<y_1\&le;\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1},$ $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{\mathrm{\&Delta;}{x}_2}\&CenterDot;\mathrm{\&Delta;}{x}_1\&le;y_2<\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2};$ Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}\left(\right|y_1|+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-\mathrm{\&Delta;}{x}_1}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{\mathrm{\&Delta;}{x}_2}.$

As Δ x ₂During≤x≤R, also be that the range section is [Δ x ₂, R],

Also promptly make up (y ₁, y ₂) in,

0≤y ₂≤Δ λ _M2Sensitivity in this range section is: $\frac{\mathrm{\&Delta;\; Y}}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}\left(\right|y_1|+y_2)}{\mathrm{\&Delta;\; x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-\mathrm{\&Delta;}{x}_1}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-\mathrm{\&Delta;}{x}_2}.$

Expression formula by sensitivity in each range section can know that the sensitivity that different range sections are corresponding different also can go to change sensitivity through adjusting each parameter, as reduce Δ x ₂With improve the range section [0, Δ x ₁) interior sensitivity.In whole range, first contact element relatively moves on 2 main deviational survey faces respectively, and second contact element also relatively moves on 2 auxilliary deviational survey faces respectively.

Above-mentioned slit gauge is when work (corresponding to displacement sensing method), and process is:

(A1) record the combination (y of the wavelength change of first, second fiber grating ₁, y ₂) (y ₁Corresponding to the positional information on main deviational survey face of first contact element, y ₂And be sent to analysis module the positional information on auxilliary deviational survey face corresponding to second contact element);

(A2) analysis module is according to above-mentioned wavelength change y ₁, y ₂With the wavelength change that obtains being suitable for and the relational expression of displacement, utilize this relational expression to know displacement x and sensitivity.

Embodiment 8:

The application examples of fiber grating displacement sensor in slit gauge according to the embodiment of the invention 1.

Figure 10 has schematically provided the structural representation of the slit gauge of the embodiment of the invention.As shown in Figure 2, first contact element on first strain beam is when the bottom of (oblique cambered surface only, the cross section of this cambered surface are the one section arc that is on the circle, and radius is r) slides into the summit from the inclined-plane, and the wavelength change that is installed in first fiber grating on first strain beam is Δ λ _M1, also be that its maximum wavelength changes.Second contact element on second strain beam is when the bottom on inclined-plane slides into the summit, and the wavelength change that is installed in second fiber grating on second strain beam is Δ λ _M2, also be that its maximum wavelength changes.

Above-mentioned first and second contact elements are one in front and one in back to install, and spacing is L, and the length of the orthogonal projection on inclined-plane is a, and maximum height is b, and the initial position of first contact element is the bottom on inclined-plane.

For above-mentioned slit gauge, range is R=L+a, if R＞2L, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

When 0≤x＜L, also be the range section for [0, L), $y_1=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x)}^2}-\frac{a^2-b^2}{2b}],$ y ₂=0, only there is first contact element to be on the inclined-plane; The sensitivity of every bit is all different in this range section;

When L≤x≤R-L, also be that the range section is [L, R-L], $y_1=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x)}^2}-\frac{a^2-b^2}{2b}],$ $y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x+L)}^2}-\frac{a^2-b^2}{2b}]$ First and second contact elements all are on the inclined-plane; The sensitivity of every bit is all different in this range section;

When R-L＜x≤R, also be the range section for (R-L, R], y ₁=Δ λ _M1, $y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x+L)}^2}-\frac{a^2-b^2}{2b}],$ Only there is second contact element to be on the inclined-plane; The sensitivity of every bit is all different in this range section.

Expression formula by sensitivity in each range section can be known, can go to change sensitivity through adjusting each parameter, as increasing L to improve sensitivity.

For above-mentioned slit gauge, range is R=L+a, if R=2L, the wavelength change y of first fiber grating ₁, second optic fiber grating wavelength changes y ₂Be respectively with the relation of probe displacement x:

When 0≤x≤L, also be that the range section is [0, L], $y_1=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x)}^2}-\frac{a^2-b^2}{2b}],$ y ₂=0, also promptly make up (y ₁, y ₂) in, 0≤y ₁≤Δ λ _M1, only have first contact element to be on the inclined-plane; The sensitivity of every bit is all different in this range section;

When L＜x≤R, also be the range section for (L, R], y ₁=Δ λ _M1, $y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x+L)}^2}-\frac{a^2-b^2}{2b}],$ Also promptly make up (y ₁, y ₂) in, 0＜y ₂≤Δ λ _M2, only have second contact element to be on the inclined-plane; The sensitivity of every bit is all different in this range section.

Finding the solution of above-mentioned equation is the state of the art, as utilizes method of interpolation to find the solution.

Expression formula by sensitivity in each range section can know that the sensitivity that different range sections are corresponding different also can go to change sensitivity through adjusting each parameter.

Above-mentioned slit gauge is when work (corresponding to displacement sensing method), and process is:

(A1) record the combination (y of the wavelength change of first, second fiber grating ₁, y ₂) (y ₁Corresponding to the positional information on main deviational survey face of first contact element, y ₂And be sent to analysis module the positional information on auxilliary deviational survey face corresponding to second contact element);

(A2) analysis module is according to above-mentioned wavelength change y ₁, y ₂With the wavelength change that obtains being suitable for and the relational expression of displacement, utilize this relational expression to know displacement x and sensitivity.

What provide among the foregoing description 2-8 all is the displacement with respect to zero point (like contact element all in the plane); Can certainly calculate the displacement in the time period; Computing method are: the last time point of said time period, first time point are poor with respect to the displacement at zero point, and this computing method are to understand easily for those skilled in the art.

Exemplarily provided the situation of two, three fiber gratings and strain beam among the foregoing description 2-8; Certainly can also be four or more than; Measuring principle and the foregoing description 2-8 have in essence identical; This is to understand easily for a person skilled in the art, and on embodiment 2-8 basis, need not pay creative work and can obtain.

Claims (11)

1. fiber grating displacement sensor, said displacement transducer comprises:

At least two fiber gratings, an end of said fiber grating is fixed, and the other end is installed in respectively on the different strain beams;

At least two strain beams, an end of said strain beam is fixed, and has the contact element that contacts with the inclined-plane on the strain beam;

The inclined-plane; In difference constantly, the combination of the positional information of contact element on the inclined-plane at least two strain beams has difference; When the external world had displacement, said contact element had on said inclined-plane and relatively moves, and the said strain beam that strain takes place makes said fiber grating produce strain;

Probe, said probe is connected with said inclined-plane;

Analysis module, said analysis module obtains extraneous displacement according to the combination of the strain of said fiber grating.

2. displacement transducer according to claim 1 is characterized in that: said inclined-plane is one, and the contact element of said at least two strain beams divides the time to be located on said inclined-plane, perhaps is in respectively on the differing heights on said inclined-plane.

3. displacement transducer according to claim 1 is characterized in that: said inclined-plane is two or more, and the contact element of said at least two strain beams can relatively move on one or more inclined-planes respectively.

4. displacement transducer according to claim 3 is characterized in that: at synchronization, only have a contact element to be on the inclined-plane, perhaps different contact elements is in respectively on the different inclined-planes.

5. displacement transducer according to claim 1 is characterized in that: said inclined-plane is plane or curved surface.

6. according to the arbitrary described displacement transducer of claim 2 to 5, it is characterized in that: said analysis module is used for knowing the residing range of extraneous displacement, sensitivity interval according to the combination of the strain of said fiber grating.

7. fiber grating displacement method for sensing, said method for sensing may further comprise the steps:

When (A1) external world had displacement, probe promoted the inclined-plane motion, and the contact element at least two strain beams changes with the combination of the relative position information on said inclined-plane, thus feasible at least two fiber grating generation strains that are connected with strain beam respectively;

(A2) analyze the combination of the strain of said at least two fiber gratings, thereby know extraneous displacement.

8. method for sensing according to claim 7 is characterized in that: the analytical approach that said step (A2) adopts is:

(B1) combination according to said relative position information draws the residing range of extraneous displacement interval;

(B2) the extraneous displacement corresponding to different sensitivity is known in the influence to light wavelength, the said interval that cause according to the strain of said fiber grating.

9. method for sensing according to claim 7 is characterized in that: in the process that relatively moves of inclined-plane and contact element, at least two contact elements divide the time to be located on the inclined-plane, or are in simultaneously on the different inclined-planes.

10. method for sensing according to claim 9 is characterized in that: in the process of relatively moving, contact element relatively moves on an inclined-plane at least.

11. according to the arbitrary described method for sensing of claim 7 to 10, it is characterized in that: said inclined-plane is plane or curved surface.

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