CN102749035B - 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 when small stretching, the wavelength of Fiber Bragg Grating FBG (hereinafter referred to as grating) and the small displacement of stretching linear.Namely fibre-optical raster crack meter is by certain device, and this micro-displacement of Linear Amplifer, realizes the measurement to outside larger displacement.

Fig. 1 schematically illustrates the schematic diagram of slit gauge in prior art, as shown in Figure 1, when the external world has displacement, during the pull bar pulling motion of slit gauge, the upper top that inclined-plane then can cause feeler lever is connected with pull bar, feeler lever pushes up and can cause the change of grating strain beam deflection, the change of this amount of deflection then can be passed to grating, makes grating that the wavelength variations measured occur.Little in grating strain beam elastic range amount of deflection change can approximately linear, and the slit gauge of this structure, namely by the linear transformation of inclined-plane-amount of deflection, realizes the measurement of pull bar Large travel range.Range is the horizontal length on inclined-plane, sensitivity is that feeler lever is in bottom inclined-plane, top time grating wavelength difference and range ratio.

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

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

When 2, keeping maximum sensitivity, range cannot be improved;

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

Summary of the invention

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

The object of the invention is to be achieved through the following technical solutions:

Fiber grating displacement sensor, institute's displacement sensors comprises:

At least two fiber gratings, one end of described fiber grating is fixed, and the other end is arranged on different strain beams respectively;

At least two strain beams, one end of described strain beam is fixed, and strain beam has the contact element with contact of incline plane;

Inclined-plane; Not in the same time, the combination of the positional information of the contact element at least two strain beams on inclined-plane has difference; When the external world has displacement, described contact element has relative movement on described inclined-plane, and the described strain beam that strain occurs makes described fiber grating produce strain;

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

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

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

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

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

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

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

Object of the present invention is also achieved by the following technical programs:

Fiber Bragg Grating Displacement Sensor method, described method for sensing comprises the following steps:

(A1), when the external world has displacement, probe promotes inclined-plane motion, and the combination of the relative position information on the contact element at least two strain beams and described inclined-plane changes, thus at least two fiber gratings be connected with strain beam are respectively strained;

(A2) combination of the strain of at least two fiber gratings described in analysis, thus know extraneous displacement.

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

(B1) show that according to the combination of described relative position information the range residing for extraneous displacement is interval;

(B2) according to the strain of described fiber grating and the impact of the wavelength on light caused, described interval and know extraneous displacement.

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

According to above-mentioned method for sensing, alternatively, in relative movement thereof, at least there is relative movement in contact element on an inclined-plane.

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

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

1, when range is certain, (exponentially) improves the sensitivity of displacement transducer, and different version can improve different multiples;

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

3, when sensitivity is certain, the range of displacement transducer is improved.

Accompanying drawing explanation

With reference to accompanying drawing, disclosure of the present invention will be easier to understand.Those skilled in the art it is easily understood that: these accompanying drawings only for illustrating technical scheme of the present invention, and and are not intended to be construed as limiting protection scope of the present invention.In figure:

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

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

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

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

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

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

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

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

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

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

Embodiment

Fig. 2-10 and following description describe Alternate embodiments of the present invention and how to implement to instruct those skilled in the art and to reproduce the present invention.In order to instruct technical solution of the present invention, simplifying or having eliminated some conventional aspects.Those skilled in the art should understand that the modification that is derived from these embodiments or replace will within the scope of the invention.Those skilled in the art should understand that following characteristics can combine to form multiple modification of the present invention in every way.Thus, the present invention is not limited to following Alternate embodiments, and only by claim and their equivalents.

Embodiment 1:

Fig. 2 schematically illustrates the basic block diagram of the fiber grating displacement sensor of the embodiment of the present invention.As shown in Figure 2, described sensor comprises:

At least two fiber gratings, as Bragg grating, one end of described fiber grating is fixed, and the other end is arranged on different strain beams respectively;

At least two strain beams, one end of described strain beam is fixed, and strain beam has the contact element with contact of incline plane; The initial position of at least one contact element is in the bottom on inclined-plane; Described strain beam is the state of the art, does not repeat them here.

Inclined-plane; Not in the same time, the combination of the positional information of the contact element at least two strain beams on inclined-plane has difference, also namely described contact element is in different from the relative position on inclined-plane, as: the differing heights place on same inclined-plane, or a part of contact element is in another part on inclined-plane and is in plane, or the identical At The Height on different inclined-plane, or the differing heights place on different inclined-plane; When the external world has displacement, described contact element has relative movement on described inclined-plane, and the described strain beam that strain occurs makes described fiber grating produce strain;

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

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

Certainly, described sensor also comprises light source, shunt and spectrometer, and the light that light source sends enters optical fiber by a road of shunt, through fiber grating, part Guang Beiyuan road reflects, and is received, can obtain the wavelength variations of fiber grating after shunt by spectrometer.The prior art that these devices and concrete connected mode are easy understand for those skilled in the art, does not repeat them here.

Fig. 3 schematically illustrates the process flow diagram of the Fiber Bragg Grating Displacement Sensor method of the embodiment of the present invention.As shown in Figure 3, described method for sensing comprises the following steps:

(A1) when the external world has displacement, probe promotes inclined-plane motion, the combination of the relative position information on the contact element at least two strain beams and described inclined-plane changes, namely also described contact element is in different from the relative position on inclined-plane, and as the differing heights place on same inclined-plane, or a part of contact element is in another part on inclined-plane and is in plane, or the identical At The Height on different inclined-plane, or the differing heights place on different inclined-plane; Thus at least two fiber gratings be connected with strain beam are respectively strained;

(A2) combination of the strain of at least two fiber gratings described in analysis, thus know extraneous displacement, the sensitivity that this displacement is corresponding certain.

Be according to the benefit that the embodiment of the present invention 1 reaches: use at least two fiber gratings, make there is different wavelength variations when same displacement, thus obtain different wavelength variations combinations, also namely different sensitivity.

Embodiment 2:

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

Fig. 2 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 2, when the first contact element on the first strain beam slides into summit from the bottom of inclined-plane (only a tapered plane), the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.When the second contact element on second strain beam slides into summit from the bottom on inclined-plane, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.

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

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

As 0≤x < L, also namely range section be [0, L), y ₂=0, also namely combine (y ₁, y ₂) in, the first contact element is only had to be on inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}$

As L≤x≤R-L, also namely range section is [L, R-L], also namely (y is combined 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 are all on inclined-plane; Sensitivity in this range section is:

As R-L < x≤R, also namely range section be (R-L, R], y ₁=Δ λ _m1, also namely (y is combined ₁, y ₂) in, the second contact element is only had to be on inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}.$

From the expression formula of sensitivity in each range section, go to change sensitivity by adjusting each parameter, as increased L to improve sensitivity.

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

As 0≤x≤L, also namely range section is [0, L], y ₂=0, also namely combine (y ₁, y ₂) in, 0≤y ₁≤ Δ λ _m1, only have the first contact element to be on inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{L}$

As L < x≤R, also namely range section be (L, R], y ₁=Δ λ _m1, also namely (y is combined ₁, y ₂) in, 0 < y ₂≤ Δ λ _m2, only have the second contact element to be on inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{L}.$

From the expression formula of sensitivity in each range section, the sensitivity that different range section is corresponding different, also goes to change sensitivity by adjusting each parameter, as reduced L to improve sensitivity.In whole range, synchronization only has a contact element to be on inclined-plane.

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

(A1) combination (y of the wavelength variations of first, second fiber grating is recorded ₁, y ₂) (y ₁corresponding to the positional information on main deviational survey face of the first contact element, y ₂the positional information on auxiliary deviational survey face corresponding to the second contact element), and be sent to analysis module;

(A2) analysis module is according to above-mentioned wavelength variations y ₁, y ₂to obtain the relational expression of wavelength variations and the displacement be suitable for, this relational expression is utilized to know displacement x and sensitivity.

Be according to the benefit that the embodiment of the present invention 2 reaches: use at least two fiber gratings, make there is different wavelength variations when same displacement, thus obtain different wavelength variations combinations, also namely different sensitivity.Compared with prior art, improve sensitivity when range is identical, too increase the combination of sensitivity; When sensitivity is identical, improve range.

Embodiment 3:

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

Fig. 4 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 4, when the first contact element on the first strain beam slides into summit from the bottom of inclined-plane (only a tapered plane), the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.When the second contact element on second strain beam slides into summit from the bottom on inclined-plane, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.When the 3rd contact element on 3rd strain beam slides into summit from the bottom on inclined-plane, the wavelength variations being arranged on the 3rd fiber grating on the 3rd strain beam is Δ λ _m3, also i.e. its maximum wavelength change.

Above-mentioned first, second, and third contact element is installed before and after being, spacing is respectively L ₁, L ₂, L=L ₁+ L ₂be less than the length a of the orthogonal projection on inclined-plane.The initial position of the 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 variations y of the first fiber grating ₁, second optic fiber grating wavelength change y ₂with the 3rd optic fiber grating wavelength change y ₃be respectively with the relation of probe displacement x:

As 0≤x≤L ₁time, also namely range section is [0, L ₁], y ₂=0, y ₃=0, also namely combine (y ₁, y ₂, y ₃) in, the first contact element is only had to be on 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 namely range section is (L ₁, L), y ₃=0, also namely combine (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 are all on same inclined-plane; Sensitivity in this range section is:

As L≤x≤R-L, also namely 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 namely (y is combined 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, and third contact element is all on same inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2+y_3)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-L}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}$

As R-L < x < R-L+L ₁time, also namely 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 namely (y is combined ₁, y ₂, y ₃) in, $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-L}\&CenterDot;(R-L-L_1)<y_2<\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2},$ $\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(R-2L)<y_3<\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m3}}{R-L}\&CenterDot;(R-L-L_2),$ Second and the 3rd contact element be on inclined-plane; Sensitivity in this range section is:

Work as R-L+L ₁during≤x≤R, also namely 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 namely (y is combined 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 inclined-plane; Sensitivity in this range section is:

From the expression formula of sensitivity in each range section, the sensitivity that different range section is corresponding different, also goes to change sensitivity by adjusting each parameter, as increased L to improve sensitivity.

Embodiment 4:

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

Fig. 5 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 5, when the first contact element on the first strain beam slides into summit from the bottom on the first inclined-plane, the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.When the second contact element on second strain beam slides into summit from the bottom on the second inclined-plane, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.

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

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

As 0≤x < b, also namely range section be [0, b), y ₁=0, also namely (y is combined ₁, y ₂) in, 0≤y ₂< Δ λ _m2, only have the second contact element to be on inclined-plane; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}$

As b≤x≤R, also namely range section is [b, R], y ₂=Δ λ _m2, also namely combine (y ₁, y ₂) in, 0≤y ₁≤ Δ λ _m1, only have the first contact element to be on inclined-plane, the sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-b}$

From the expression formula of sensitivity in each range section, the sensitivity that different range section is corresponding different, also goes to change sensitivity by adjusting each parameter.

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

As 0≤x≤a ₁time, also namely range section is [0, a ₁], y ₁=0, also namely (y is combined ₁, y ₂) in, the second contact element is only had to be on 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 ₂time, also namely range section is (a ₁, a ₁+ a ₂), also namely (y is combined ₁, y ₂) in, 0 < y ₁< Δ λ _m1, first contact element and the second contact element are all on inclined-plane; Sensitivity in this range section is:

Work as a ₁+ a ₂during≤x≤b, also namely range section is [a ₁+ a ₂, b], y ₁=Δ λ _m1, also namely (y is combined ₁, y ₂) in, only the second contact element is on inclined-plane, and the sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}(y_1+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}.$

From the expression formula of sensitivity in each range section, the sensitivity that different range section corresponding part is identical, also goes to change sensitivity by adjusting each parameter, as reduced b to improve sensitivity.

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

(A1) combination (y of the wavelength variations of first, second fiber grating is recorded ₁, y ₂) (y ₁corresponding to the positional information on main deviational survey face of the first contact element, y ₂the positional information on auxiliary deviational survey face corresponding to the second contact element), and be sent to analysis module;

(A2) analysis module is according to above-mentioned wavelength variations y ₁, y ₂to obtain the relational expression of wavelength variations and the displacement be suitable for, this relational expression is utilized to know displacement x and sensitivity.

Embodiment 5:

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

Fig. 7 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 7, bold portion is main deviational survey face, have 2 main deviational survey faces, and the angle of wedge on each inclined-plane is different; When the first contact element on first strain beam slides into summit from the bottom in main deviational survey face, the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.

Dotted line is auxiliary deviational survey face, only 1 inclined-plane, and when the second contact element on the second strain beam slides into summit from the bottom in auxiliary deviational survey face, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.Above-mentioned first and second contact elements install side by side, and initial position is all in the bottom on inclined-plane.

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

As 0≤x < Δ x ₁time, also namely range section is [0, Δ x ₁), also namely (y is combined ₁, y ₂) in, 0≤y ₁< Δ λ _m1, first contact element and the second contact element are all on inclined-plane, and the sensitivity in this range section is:

As Δ x ₁during≤x≤R, also namely range section is [Δ x ₁, R], also namely (y is combined ₁, y ₂) in, 0≤y ₁≤ Δ λ _m1, first contact element and the second contact element are all on inclined-plane, and the sensitivity in this range section is:

From the expression formula of sensitivity in each range section, the sensitivity that different range section is corresponding different, also goes to change sensitivity, as reduced Δ x by adjusting each parameter ₁to improve range section [0, Δ x ₁) in sensitivity.In whole range, the first contact element is relative movement on 2 main deviational survey faces respectively, and the only relative movement on an auxiliary deviational survey face of the second contact element.

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

(A1) combination (y of the wavelength variations of first, second fiber grating is recorded ₁, y ₂) (y ₁corresponding to the positional information on main deviational survey face of the first contact element, y ₂the positional information on auxiliary deviational survey face corresponding to the second contact element), and be sent to analysis module;

(A2) analysis module is according to above-mentioned wavelength variations y ₁, y ₂to obtain the relational expression of wavelength variations and the displacement be suitable for, this relational expression is utilized to know displacement x and sensitivity.

Embodiment 6:

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

Fig. 8 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 8, bold portion is main deviational survey face, total a main deviational survey face, and the angle of wedge on each inclined-plane is identical; When the first contact element on first strain beam slides into summit from the bottom in main deviational survey face, the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.

Dotted line is auxiliary deviational survey face, and when the second contact element on the second strain beam slides into summit from the bottom in auxiliary deviational survey face, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.Above-mentioned first and second contact elements install side by side, and initial position is all in the bottom on inclined-plane.

For above-mentioned slit gauge, range is R, then the second optic fiber grating wavelength change y ₂following relation is had with probe displacement x:

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

As the second optic fiber grating wavelength change y ₂for time, the wavelength variations y of the first fiber grating ₁with the pass 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 above formula, n is positive integer, represents the first contact element and is in from the main deviational survey face of n-th from left to right.

In range section [0, R], the sensitivity of slit gauge is: can be gone by the number a increasing main deviational survey face to improve sensitivity.In whole range, the first contact element is relative movement on a main deviational survey face respectively, and the only relative movement on an auxiliary deviational survey face of the second contact element.

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

(A1) combination (y of the wavelength variations of first, second fiber grating is recorded ₁, y ₂) (y ₁corresponding to the positional information on main deviational survey face of the first contact element, y ₂the positional information on auxiliary deviational survey face corresponding to the second contact element), and be sent to analysis module;

(A2) analysis module is according to above-mentioned wavelength variations y ₂and draw n, n is positive integer, and also namely now the first contact element is in from which main deviational survey face from left to right;

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

Embodiment 7:

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

Fig. 9 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 9, bold portion is main deviational survey face, has 2 main deviational survey faces; When the first contact element on first strain beam slides into summit from the bottom in main deviational survey face, the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.

Dotted line is auxiliary deviational survey face, has 2 auxiliary deviational survey faces, and when the second contact element on the second strain beam slides into summit from the bottom in auxiliary deviational survey face, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.Above-mentioned first and second contact elements install side by side, and initial position is all in the bottom on inclined-plane.

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

As 0≤x < Δ x ₁time, also namely range section is [0, Δ x ₁), also namely (y is combined 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 ₂time, also namely range section is [Δ x ₁, Δ x ₂), also namely (y is combined 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 namely range section is [Δ x ₂, R], also namely (y is combined ₁, y ₂) in, 0≤y ₂≤ Δ λ _m2; Sensitivity in this range section is: $\frac{\mathrm{\&Delta;Y}}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}\left(\right|y_1|+y_2)}{\mathrm{\&Delta;x}}=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m1}}{R-\mathrm{\&Delta;}{x}_1}+\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{R-\mathrm{\&Delta;}{x}_2}.$

From the expression formula of sensitivity in each range section, the sensitivity that different range section is corresponding different, also goes to change sensitivity, as reduced Δ x by adjusting each parameter ₂to improve range section [0, Δ x ₁) in sensitivity.In whole range, the first contact element is relative movement on 2 main deviational survey faces respectively, and the also relative movement on 2 auxiliary deviational survey faces respectively of the second contact element.

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

(A1) combination (y of the wavelength variations of first, second fiber grating is recorded ₁, y ₂) (y ₁corresponding to the positional information on main deviational survey face of the first contact element, y ₂the positional information on auxiliary deviational survey face corresponding to the second contact element), and be sent to analysis module;

(A2) analysis module is according to above-mentioned wavelength variations y ₁, y ₂to obtain the relational expression of wavelength variations and the displacement be suitable for, this relational expression is utilized to know displacement x and sensitivity.

Embodiment 8:

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

Figure 10 schematically illustrates the structural representation of the slit gauge of the embodiment of the present invention.As shown in Figure 2, the first contact element on first strain beam is from an inclined-plane (only oblique cambered surface, the cross section of this cambered surface is be in one section of arc on circle, and radius is bottom r) when sliding into summit, and the wavelength variations being arranged on the first fiber grating on the first strain beam is Δ λ _m1, also i.e. its maximum wavelength change.When the second contact element on second strain beam slides into summit from the bottom on inclined-plane, the wavelength variations being arranged on the second fiber grating on the second strain beam is Δ λ _m2, also i.e. its maximum wavelength change.

Above-mentioned first and second contact elements one in front and one in back 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 the first contact element is the bottom on inclined-plane.

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

As 0≤x < L, also namely range section be [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 the first contact element to be on inclined-plane; In this range section, the sensitivity of every bit is all different;

As L≤x≤R-L, also namely 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 are all on inclined-plane; In this range section, the sensitivity of every bit is all different;

As R-L < x≤R, also namely range section be (R-L, R], y ₁=Δ λ _m1, $y_2=\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{m2}}{b}\&CenterDot;[\sqrt{{\left(\frac{a^2+b^2}{2b}\right)}^2-{(a-x+L)}^2}-\frac{a^2-b^2}{2b}],$ The second contact element is only had to be on inclined-plane; In this range section, the sensitivity of every bit is all different.

From the expression formula of sensitivity in each range section, go to change sensitivity by adjusting each parameter, as increased L to improve sensitivity.

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

As 0≤x≤L, also namely 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 namely combine (y ₁, y ₂) in, 0≤y ₁≤ Δ λ _m1, only have the first contact element to be on inclined-plane; In this range section, the sensitivity of every bit is all different;

As L < x≤R, also namely range section be (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 namely (y is combined ₁, y ₂) in, 0 < y ₂≤ Δ λ _m2, only have the second contact element to be on inclined-plane; In this range section, the sensitivity of every bit is all different.

Solving of above-mentioned equation is the state of the art, solves as utilized method of interpolation.

From the expression formula of sensitivity in each range section, the sensitivity that different range section is corresponding different, also goes to change sensitivity by adjusting each parameter.

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

(A1) combination (y of the wavelength variations of first, second fiber grating is recorded ₁, y ₂) (y ₁corresponding to the positional information on main deviational survey face of the first contact element, y ₂the positional information on auxiliary deviational survey face corresponding to the second contact element), and be sent to analysis module;

(A2) analysis module is according to above-mentioned wavelength variations y ₁, y ₂to obtain the relational expression of wavelength variations and the displacement be suitable for, this relational expression is utilized to know displacement x and sensitivity.

Provide in above-described embodiment 2-8 be all relative to zero point (as contact element all in the plane) displacement, the displacement in the time period can certainly be calculated, computing method are: the last time point of described time period, first time point are relative to the difference of the displacement at zero point, and this computing method are easy understand for those skilled in the art.

The situation of two, three fiber gratings and strain beam is exemplarily given in above-described embodiment 2-8, certainly it can also be four or more, measuring principle and above-described embodiment 2-8 are that there have in essence to be identical, this is easy understand for a person skilled in the art, and on embodiment 2-8 basis, does not need to pay creative work can obtain.

Claims (11)

1. fiber grating displacement sensor, institute's displacement sensors comprises:

At least two fiber gratings, one end of described fiber grating is fixed, and the other end is arranged on different strain beams respectively;

At least two strain beams, one end of described strain beam is fixed, and strain beam has the contact element with contact of incline plane;

Inclined-plane; Not in the same time, the combination of the positional information of the contact element at least two strain beams on inclined-plane has difference; When the external world has displacement, described contact element has relative movement on described inclined-plane, and the described strain beam that strain occurs makes described fiber grating produce strain;

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

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

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

3. displacement transducer according to claim 1, is characterized in that: described inclined-plane is two or more, and the contact element of described at least two strain beams respectively can at one with relative movement on ramp.

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

5. displacement transducer according to claim 1, is characterized in that: described 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: described analysis module is used for the combination according to the strain of described fiber grating and knows that range residing for extraneous displacement, sensitivity are interval.

7. Fiber Bragg Grating Displacement Sensor method, described method for sensing comprises the following steps:

(A1), when the external world has displacement, probe promotes inclined-plane motion, and the combination of the relative position information on the contact element at least two strain beams and described inclined-plane changes, thus at least two fiber gratings be connected with strain beam are respectively strained;

(A2) combination of the strain of at least two fiber gratings described in analysis, thus know extraneous displacement.

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

(B1) show that according to the combination of described relative position information the range residing for extraneous displacement is interval;

(B2) according to the strain of described fiber grating and the impact of the wavelength on light caused, described interval and know the extraneous displacement corresponding to different sensitivity.

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

10. method for sensing according to claim 9, is characterized in that: in relative movement thereof, and contact element at least on an inclined-plane, relative movement occurs.

11., according to the arbitrary described method for sensing of claim 7 to 10, is characterized in that: described inclined-plane is plane or curved surface 2.