CN103292744A - Roll angle measuring device and method based on diffraction grating displacement - Google Patents

Abstract

The invention discloses a roll angle measuring device and method based on diffraction grating displacement. The device comprises a dual-frequency laser, a 5% reflecting mirror, a polarization splitting prism, a diffraction grating, a first reflector and a second reflector. The diffraction grating is fixed on a to-be-measured object. The first reflector and the second reflector, serving as sensitive parts, are fixed through a first fixing support and a second fixing support to guarantee relative rest of the diffraction grating. The diffraction grating, the first reflector and the second reflector form an integral target reflector. The dual-frequency laser, the 5% reflecting mirror, a first analyzer, a second analyzer, a third analyzer, a first photoelectric receiver, a second photoelectric receiver, a third photoelectric receiver, the polarization splitting prism, a first 50% reflecting mirror, a second 50% reflecting mirror, a third 50% reflecting mirror and a high-reflecting light mirror form a measuring head. The device which is based on laser heterodyne interference, diffraction grating displacement and spatial layout is capable of realizing roll angle measuring, high in precision and high in anti-interference capability, and actual application is facilitated.

Description

A kind of rolling angle measurement device and method based on the diffraction grating shift technique

Technical field

The invention belongs to the photoelectric measurement technical field of angle, relate to a kind of rolling angle measurement device and method, be specifically related to a kind of rolling angle measurement device and method of diffraction grating shift technique of contactless difference interference.

Background technology

Any mechanical guide rail movement pair all has three revolution degree of freedom (pitching, beat and lift-over), and they are defined as pitching, beat and the lift-over angular deviation of linear movement according to the ISO10791-2:2001/GB/T18400.2-2010 standard.In three angular deviations detect, the measuring method of the angle of pitch and deflection angle and technology developed comparatively maturation and Measurement Resolution very high, as two-frequency laser interferometer method, autocollimator etc.Comparatively speaking, measuring method and the technology of existing roll angle then are difficult to satisfy high-resolution requirement, are the bottleneck problems of researchs such as angular deviation detection, numerically-controlled machine error analysis and compensation always.This mainly is because roll angle displacement plane and laser beam direction quadrature, causes high-precision optical measuring method typical, maturation (as two-frequency laser interferometer etc.) to be difficult to be competent at.Therefore, effectively measure for the high precision of roll angle, still be in a kind of research and exploratory stage both at home and abroad, still do not have ripe detection method or business-like surveying instrument and be widely used.

At present, detect the following several class methods that mainly contain of problem at high-precision roll angle: first, the electrolevel that with the gravity direction is benchmark is measured, the method is similar to traditional level meter, all based on sensitive element induction gravity, realize the difference of measurement plane and reference plane, thereby realize rolling angle measurement, though it has advantage simple in structure, easy and simple to handle, it can not measure the roll angle of vertical axes.Second, collimation laser position with position-based sensing detector (PSD) is the measurement of benchmark, principle is based on collimation laser by after the measurand of the lift-over reflection, the relative initial position of its hot spot changes and is surveyed by PSD, thereby calculate and finish rolling angle measurement, it can be easy to realize multidimensional measure, is difficult to but Measurement Resolution is subject to the performance of PSD improve, and is easy to be subjected to the influence of the angle of pitch and deflection angle.Publication number is that the patent of CN101339012A proposes a kind of roll angle measurement method and device based on grating, this method combines the characteristics of transmission-type grating and PSD technology, utilize grating as sensitive element, its positive and negative first-order diffraction light beam displacement in PSD after optics links such as lens calculates tested roll angle, and it has the characteristics of compact conformation.The 3rd, be the mensuration of benchmark with the laser orthogonal polarization orientation, this method comprises three classes of measuring based on light intensity, phase place and frequency modulation (PFM), wherein based on the polarized light phase method, has the advantage of degree of precision.Publication number is that the patent of CN1335483 is improved light path design and improved 4 times again on the basis of original method sensitivity in non-linear enhancing on the basis of polarized light phase method, but the method and device are difficult to improve its resolution again.The 4th, the interferometric method rolling angle measurement, U.S. Patent number is that Chaney has proposed a kind ofly to use the interferometer method to measure roll angle fully can to obtain very high precision in 5056921 patents, but a same long plane mirror with guide rail need be installed by this system, is difficult in practice use.Another laser interferance method, be to carry out many body diagonal linear displacements by laser interferometer to measure, solve 21 individual event geometric errors indirectly by system of equations, also comprise and try to achieve the rolling angle measurement value, but this method belongs to indirect integration measurement method, can not measure and be unfavorable for error compensation in real time.

Summary of the invention

The objective of the invention is to overcome the shortcoming of above-mentioned prior art, a kind of rolling angle measurement device and method based on the diffraction grating shift technique is provided, it is based on laser heterodyne interference, diffraction grating shift technique and space layout, not only can realize rolling angle measurement, and have precision height, characteristics that antijamming capability is strong, be conducive to practical application.

The objective of the invention is to solve by the following technical programs:

This rolling angle measurement device based on the diffraction grating shift technique comprises two-frequency laser, 5% catoptron, polarization splitting prism, diffraction grating and first and second reverberator; 5% catoptron is set behind the optical axis of described two-frequency laser, and the reflection optical axis of described 5% catoptron is provided with first analyzer and the 3rd photelectric receiver; The transmission optical axis of described 5% catoptron is provided with polarization splitting prism; Be vertically installed with diffraction grating on the transmission optical axis of described polarization splitting prism and with this optical axis; Described diffraction grating ± be respectively arranged with first reverberator and second reverberator on the 1 order diffraction optical axis; The reflection optical axis of described polarization splitting prism is provided with the one 50% spectroscopes; The emergent light axis intersection point place of described the one 50% spectroscopical transmission optical axis and described first reverberator is provided with the two 50% spectroscopes; Described the one 50% spectroscopical reflection optical axis are provided with high reflection light mirror; The emergent light axis intersection point place of the reflection optical axis of described high reflection light mirror and described second reverberator is provided with the three 50% spectroscopes; Be respectively equipped with second and third analyzer and first and second photelectric receiver on described the two 50% spectroscopes and the three 50% spectroscopical optical axises.

Further, the two ends of above-mentioned diffraction grating are provided with in order to first fixed support of fixed diffraction grating and second fixed support, and described first fixed support and the second support bracket fastened lower end are fixed first reverberator and second reverberator respectively.

Above-mentioned diffraction grating is fixed on the measurand, and as sensitive element, first and second reverberator is fixed to guarantee relative with described diffraction grating static by first and second fixed support; Constituted the target reflector of one by diffraction grating and first and second reverberator; By two-frequency laser, 5% catoptron, first, second and third analyzer and first, second and third photelectric receiver, polarization splitting prism, first, second and third 50% catoptron and high reflection light mirror constitute measuring head.

Further, above-mentioned first and second reverberator adopts Si Mite prism or high reflection mirror.

The present invention also proposes a kind of roll angle measurement method based on said apparatus, may further comprise the steps:

1) light beam that sends of two-frequency laser is divided into two-beam through 5% spectroscope, and wherein folded light beam is received behind first analyzer and the 3rd photelectric receiver, is considered as reference signal;

2) transmitted light beam by 5% spectroscope outgoing is divided into S light and P light through behind the polarization splitting prism; S light is divided into two bundles through the first 50% spectroscopes after polarization splitting prism reflection, wherein transmitted light beam incides second analyzer and first photelectric receiver is received after the two 50% mirror reflects, it is the reference beam of second photelectric receiver, wherein folded light beam incides the 3rd analyzer and second photelectric receiver is received after high reflection mirror and the three 50% mirror reflects, is the reference beam of the 3rd photelectric receiver; Diffraction takes place in P light transmission polarization splitting prism normal incidence behind diffraction grating, wherein+1 the order diffraction light beam is after the reflection of first reverberator, with the outgoing of diffraction grating orthogonal directions, see through that the two 50% catoptrons incide second analyzer and first photelectric receiver is received, it is the measuring beam of second photelectric receiver, in like manner, wherein-1 the order diffraction light beam is after the reflection of second reverberator, with the outgoing of diffraction grating orthogonal directions, seeing through that the three 50% catoptrons incide the 3rd analyzer and second photelectric receiver is received, is the measuring beam of the 3rd photelectric receiver; The reference beam that second photelectric receiver receives and the interference signal of measuring beam are considered as+1 grade of measuring-signal, and the reference beam that the 3rd photelectric receiver receives and the interference signal of measuring beam are considered as-1 grade of measuring-signal;

3) ± 1 grade measuring-signal, reference signal are finally counted value C by counter through comparer, counting and Acquisition Circuit respectively _{+ 1}, C _-1And C _R, by heterodyne technology measuring-signal and reference signal are carried out difference and can get Δ C _{+ 1}With Δ C _-1, data are delivered in the PC the most at last, and difference gets N again, calculates the micro-displacement S of grating according to the Doppler effect of diffraction grating, according to the geometric relationship α=S/R of small displacement S and corner, solves tested roll angle α, and wherein R is the lift-over radius.

The present invention has following beneficial effect:

The present invention adopts reflective diffraction gratings as the detecting element of rolling angle measurement, and two Si Mite prisms elements such as (or adopt) high reflection mirrors are fixed on the positive and negative first-order diffraction optical axis of diffraction grating by support respectively, keep relative static with diffraction grating, and keep positive and negative first-order diffraction light beam and diffraction grating quadrature (namely parallel with the diffraction grating incident light).Diffraction grating and two Si Mite prisms are installed on the measurand as target reflector.The measuring head of having been formed system by two-frequency laser, 5% catoptron, polarization splitting prism, 50% spectroscope, high reflection mirror, photelectric receiver etc.The function of measuring head is included as diffraction grating measuring beam (light source) is provided, and be responsible for to receive the measuring beam of positive and negative first-order diffraction, and the reception of interference signal, signal processing etc.This rolling angle measurement device and method based on the diffraction grating shift technique, it is in conjunction with laser heterodyne interference and diffraction grating shift technique, make the measuring beam beginning maintenance of travelling to and fro between between target reflector and the measuring head and diffraction grating quadrature eventually by light path design and geometry design, namely consistent with direction of linear motion.Characteristics such as therefore, this measurement mechanism is not subjected to the influence of linear movement, and has ripe laser heterodyne interference technology and be the basis, and measuring accuracy height, antijamming capability are strong.

Compare with existing roll angle detection method, the inventive method and device have the advantage of ultrahigh resolution.Method of the present invention is applicable to high-precision commercial measurement field, be particularly useful for precise guide rail kinematic pair, high-grade, digitally controlled machine tools the precision measure of kinematic axis roll angle, assessment of performance, error is traced to the source and field such as compensation, its widespread use can promote the development of detection techniques such as Precision Machining, equipment manufacturing.

Description of drawings

Fig. 1 is principle of device structural front view of the present invention;

Fig. 2 is the left view of Fig. 1;

Fig. 3 is the diffraction synoptic diagram of diffraction grating of the present invention.

Wherein: 1 is two-frequency laser; 2 is 5% catoptron; 3 is first photelectric receiver; 4 is polarization splitting prism; 5 is the one 50% spectroscopes; 6 is the two 50% spectroscopes; 7 is high reflection light mirror; 8 is Yi Si Mite prism; 9 is first fixed support; 10 is diffraction grating; 11 is second fixed support; 12 is Er Si Mite prism; 13 is the three 50% spectroscopes; 14 is second photelectric receiver; 15 is the 3rd photelectric receiver; 101 is measuring head; 102 is target reflector.

Embodiment

Below in conjunction with accompanying drawing the present invention is done and to describe in further detail:

Referring to Fig. 1 and Fig. 2, the present invention is based on the rolling angle measurement device of diffraction grating shift technique, comprise two- frequency laser 1,5% catoptron 2, polarization splitting prism 4, diffraction grating 10, first and second fixed support 9,11 and first and second reverberator 8,12, like that close special prism or high reflection mirror (be example with the Si Mite prism); The reflection optical axis that is provided with 5% catoptron, 2,5% catoptrons 2 behind the optical axis of two-frequency laser 1 is provided with first analyzer and the 3rd photelectric receiver 15.The transmission optical axis of 5% catoptron 2 is provided with polarization splitting prism 4.Be vertically installed with diffraction grating 10 on polarization splitting prism 4 transmission optical axis and with this optical axis; By first and second fixed support 9,10 diffraction grating 10 ± 1 order diffraction optical axis is respectively arranged with first and second reverberator 8,12.The reflection optical axis of polarization splitting prism 4 is provided with the one 50% spectroscopes 5; The transmission optical axis of the one 50% spectroscopes 5 and the emergent light axis intersection point place of first reverberator 8 are provided with the two 50% spectroscopes 6; The reflection optical axis of the one 50% spectroscopes 5 is provided with high reflection light mirror 7; The emergent light axis intersection point place of the reflection optical axis of high reflection light mirror 7 and second reverberator 12 is provided with the three 50% spectroscopes 13.Wherein be respectively equipped with second analyzer, three analyzers and first photelectric receiver 3 and second photelectric receiver 14 on the optical axis of the two 50% spectroscopes 6 and the three 50% spectroscopes 13.As shown in the figure, two- frequency laser 1,5% catoptron 2 of the present invention, polarization splitting prism 4, first, second and third 50% spectroscope 5,6,13, high reflection mirror 7, the first to three analyzers and first, second and third photelectric receiver 3,14,15 etc. have been formed the measuring head 101 of system; Diffraction grating 10 and first and second reverberator 8,12 and first and second fixed support 9,11 form target reflectors 102.Guarantee light beam parallel come and go (consistent with the measured object direction of linear motion) between target reflector 102 and measuring head 101 by the Si Mite prism (or adopting high reflection mirror etc.) as reverberator.

Based on above device, the roll angle measurement method that the present invention proposes is specific as follows:

1) light beam that sends of two-frequency laser 1 is divided into two-beam through 5% spectroscope 2, and wherein folded light beam is received behind first analyzer and the 3rd photelectric receiver 15, is considered as reference signal.

2) transmitted light beam by 2 outgoing of 5% spectroscope is divided into S light and P light through behind the polarization splitting prism 4; S light is divided into two bundles through the first 50% spectroscopes 5 after polarization splitting prism 4 reflection, wherein transmitted light beam incides second analyzer and first photelectric receiver 3 is received after 6 reflections of the two 50% catoptrons, it is the reference beam of second photelectric receiver 14, wherein folded light beam incides the 3rd analyzer and second photelectric receiver 14 is received after high reflection mirror 7 and 13 reflections of the three 50% catoptrons, is the reference beam of the 3rd photelectric receiver 15; Diffraction takes place to diffraction grating 10 backs in P light transmission polarization splitting prism 4 normal incidences, wherein+1 the order diffraction light beam is after reflections such as Si Mite prism 8 or employing high reflection mirror, with diffraction grating 10 orthogonal directions outgoing, see through that the two 50% catoptrons 6 incide second analyzer and first photelectric receiver 3 is received, it is the measuring beam of second photelectric receiver 14, in like manner, wherein-1 the order diffraction light beam through Si Mite prism 12(or adopt high reflection mirror etc.) after the reflection, with diffraction grating 10 orthogonal directions outgoing, seeing through that the three 50% catoptrons 13 incide the 3rd analyzer and second photelectric receiver 14 is received, is the measuring beam of the 3rd photelectric receiver 15; The reference beam that second photelectric receiver 14 receives and the interference signal of measuring beam are considered as+1 grade of measuring-signal, and the reference beam that the 3rd photelectric receiver 15 receives and the interference signal of measuring beam are considered as-1 grade of measuring-signal.

3) ± 1 grade measuring-signal, the treated circuit of reference signal difference are finally by counter counting value C _{+ 1}, C _-1And C _R, by heterodyne technology measuring-signal and reference signal are carried out difference and can get Δ C _{+ 1}With Δ C _-1Data are delivered in the PC again that difference gets N the most at last, can calculate the micro-displacement S of grating thus according to the Doppler effect of diffraction grating, be the lift-over radius according to the geometric relationship α=S/R(R of small displacement S and corner) solve tested roll angle α.

In the inventive method and the device, adopt diffraction grating as the sensitive element of rolling angle measurement, constituted target reflector with it and corresponding Si Mite prism thereof, can be fixed on the measured object with its rotation.Sharp difference interference technology detects the micro-displacement that causes because of rotation with measuring beam normal incidence to reflective diffraction gratings, thereby can solve roll angle according to the geometric relationship of rotating.

This method combines ripe laser heterodyne interference and diffraction grating shift technique, based on the Doppler shift principle, carries out rolling angle measurement.It has high precision, better anti-interference characteristics.It is vertical with the angular displacement direction and cause the not high problem of sensitivity that measuring beam normal incidence has solved rolling angle measurement medium sensitivity direction to the light path design of diffraction grating.The Si Mite prism or adopt high reflection mirror etc. make ± 1 diffracted beam is parallel with incident light namely parallel with the direction of linear motion of measurand, has guaranteed that it is not subjected to the interference of linear movement.It is applicable to the kinematic axis roll angle error measure of precise guide rail kinematic pair, numerical control equipment.

Referring to Fig. 2, the course of work of the present invention is as follows: the light beam that two-frequency laser 1 sends is divided into two-beam through 5% spectroscope 2, and wherein folded light beam is received behind first analyzer and photelectric receiver 15, is considered as reference signal.

Transmitted light beam by 2 outgoing of 5% spectroscope is divided into S light and P light through behind the polarization splitting prism 4; S light is divided into two bundles through 50% spectroscope 5 after polarization splitting prism 4 reflections, wherein transmitted light beam incides second analyzer and photelectric receiver 3 is received after the reflection of 50% catoptron 6, it is the reference beam of second receiver, wherein folded light beam incides the 3rd analyzer and photelectric receiver 14 is received after high reflection mirror 7 and the reflection of 50% catoptron 13, is the reference beam of the 3rd receiver; Diffraction takes place to diffraction grating 10 backs in P light transmission polarization splitting prism 4 normal incidences, wherein+1 the order diffraction light beam is after reflections such as Si Mite prism or employing high reflection mirror, with diffraction grating 10 orthogonal directions outgoing, see through that 50% catoptron 6 incides second analyzer and photelectric receiver 3 is received, it is the measuring beam of second receiver, in like manner, wherein-1 the order diffraction light beam is after reflections such as Si Mite prism or employing high reflection mirror, with diffraction grating 10 orthogonal directions outgoing, seeing through that 50% catoptron 13 incides the 3rd analyzer and photelectric receiver 14 is received, is the measuring beam of the 3rd receiver; The reference beam that second receiver receives and the interference signal of measuring beam are considered as+1 grade of measuring-signal, and the reference beam that the 3rd receiver receives and the interference signal of measuring beam are considered as-1 grade of measuring-signal.

± 1 grade of measuring-signal, the treated circuit of reference signal difference are finally counted value C by counter _{+ 1}, C _-1And C _R, by heterodyne technology measuring-signal and reference signal are carried out difference and can get Δ C _{+ 1}With Δ C _-1Data are delivered in the PC again that difference gets N the most at last, can calculate the micro-displacement S of grating thus according to the Doppler effect of diffraction grating, be the lift-over radius according to the geometric relationship α=S/R(R of small displacement S and corner) solve tested roll angle α.

Its main measuring principle and mathematic(al) representation (mathematical model) are as follows:

As shown in Figure 3, diffraction takes place in incident light normal incidence (charging to firing angle is i, equals 0 °) to diffraction grating, establish ± emergence angle of 1 order diffraction light beam is θ.Therefore, can be got by grating equation:

dsinθ＝±λ (1)

In the formula, d is grating constant.

As depicted in figs. 1 and 2, when diffraction grating makes it produce linear movement among a small circle because of the lift-over of measurand, establishing its movement velocity is V, and corresponding micro-displacement is S, then by the Doppler shift principle as can be known:

$\mathrm{\Δ}{f}_{\±1}=\frac{V\cos (90-\mathrm{\θ})}{\mathrm{\λ}}---\left(2\right)$

In the formula, Δ f _{± 1}Be expressed as ± it is frequency shift amount that 1 order diffraction light frequency changes.λ is Wavelength of Laser.

Can be got by formula (1) and (2):

$\mathrm{\Δ}{f}_{\±1}=\±\frac{V}{d}---\left(3\right)$

As depicted in figs. 1 and 2, two-frequency laser sends the double-frequency laser bundle of the approaching direction of vibration quadrature of two frequencies, makes its frequency be respectively f ₁And f ₂By light path and principle as can be known, reference signal I _RBe that to be received by first analyzer and photelectric receiver be f ₁-f ₂Signal, can be expressed as:

In the formula, make f ₁And f ₂Light intensity equate to be I ₁=I ₂=I _Av,

Be f ₁And f ₂Phase differential.

The P light positive that sees through polarization splitting prism incides diffraction grating and is measuring beam, makes that the P light frequency is f ₁, then the S light frequency is f ₂According to formula (3) as can be known, after diffraction takes place to the grating place in measuring beam, the generation Doppler shift of ± 1 order diffraction light beam, its frequency no longer is f ₁, and should be expressed as:

f _±1＝f ₁±Δf _±1 (5)

Can be got by formula (5) and (3):

$f_{\&PlusMinus;1}={\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="HDA00003313017000021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1\&PlusMinus;\frac{V}{d}---\left(6\right)$

In the formula, f _{± 1}The frequency of expression ± 1 order diffraction light beam (measuring beam behind the diffraction).

Therefore, received respectively ± the beat frequency interference signal I of 1 order diffraction light beam (measuring beam behind the diffraction) its corresponding S light (reference beam) by second and third photelectric receiver _{± 1}, it can be expressed as:

Because the light intensity amplitude can be by the treatment circuit adjustment, and formula (6) substitution formula (7):

Formula (8) show the speed V of diffraction grating and corresponding micro-displacement S be modulated onto ± the phase place Ψ of the beat frequency interference signal (grade measuring-signal namely ± 1) of 1 order diffraction light beam and corresponding reference beam in, make signal light intensity along with the change of displacement S strong and weak cyclical variation take place.

According to frequency be phase place time-derivative namely And counter is that integer operation is namely desirable Integral part.Therefore, can be to the count number C of measuring-signal by formula (8) _{± 1}:

$C_{\&PlusMinus;1}={\&Integral;}_0^T(1/2\mathrm{\&pi;})(\mathrm{d\&psi;}/\mathrm{dt})\mathrm{dt}={\&Integral;}_0^T(f_1-f_2\&PlusMinus;\frac{V}{d})\mathrm{dt}=(f_1-f_2\&PlusMinus;\frac{V}{d})T---\left(9\right)$

In like manner, reference signal is counted, can be got its count number C by formula (4) _RFor:

$C_R={\&Integral;}_0^T(1/2\mathrm{\&pi;})(\mathrm{d\&psi;}/\mathrm{dt})\mathrm{dt}={\&Integral;}_0^T(f_1-f_2)\mathrm{dt}=(f_1-f_2)T---\left(10\right)$

By ± 1 grade of measuring-signal and reference signal mixing or count difference value computing, namely formula (9) and (10) differ and can get:

$C_{\&PlusMinus;1}-C_R=\&PlusMinus;\frac{V}{d}T---\left(11\right)$

Because S=VT, and make N _{± 1}=C _{± 1}-C _R0 corresponding frequencies that causes of expression pattern displacement changes the number of counting through counter.Then can get displacement measurement by (11) is:

S _±1＝±N _±1·d (12)

Obviously, formula (12) shows that displacement measurement resolution is grating constant d.

In order further to improve displacement resolution, can be got by formula (9) by ± 1 grade of mutual mixing of measuring-signal or count difference value computing:

$S=(C_{+1}-C_{-1})\frac{d}{2}=N\&CenterDot;\frac{d}{2}---\left(13\right)$

In the formula, make N=C _{+ 1}-C _-1, poor for the counting of ± 1 grade of measuring-signal.

Formula (13) thus show that ± 1 grade of measuring-signal is carried out heterodyne can get higher displacement measurement resolution.

As shown in Figure 1, O is the lift-over center, and the geometric relationship of roll angle α and micro-displacement S and lift-over radius R can be expressed as:

$\mathrm{\&alpha;}=\frac{S}{R}---\left(14\right)$

Can be solved the mathematic(al) representation of tested roll angle α by formula (13) and (14):

$a=\frac{\mathrm{Nd}}{2R}---\left(15\right)$

From this mathematical model as can be known, determine under the known situation that when the lift-over radius angular measurement sensitivity is directly proportional with displacement measurement resolution, namely only relevant with grating constant d.The more little angular measurement sensitivity of d is more high.Consider ± 1 grade of light distribution and light channel structure layout that d is value in 1.25～0.625 mu m ranges usually.Displacement measurement resolution can be brought up to nanoscale by subdivide technology such as electronic fine-grained method, therefore final measuring sensitivity of rotating corner can reach 10 ^-2When μ rad or 0.002arcsec(are 0.1m when the R value).

Compare with existing roll angle detection method, this inventive method and device have the advantage of ultrahigh resolution.Method of the present invention is applicable to high-precision commercial measurement field, be particularly useful for precise guide rail kinematic pair, high-grade, digitally controlled machine tools the precision measure of kinematic axis roll angle, assessment of performance, error is traced to the source and field such as compensation, its widespread use can promote the development of detection techniques such as Precision Machining, equipment manufacturing.

Claims (5)

1. the rolling angle measurement device based on the diffraction grating shift technique is characterized in that, comprises two-frequency laser (1), 5% catoptron (2), polarization splitting prism (4), diffraction grating (10) and first and second reverberator (8,12); 5% catoptron (2) is set behind the optical axis of described two-frequency laser (1), and the reflection optical axis of described 5% catoptron (2) is provided with first analyzer and the 3rd photelectric receiver (15); The transmission optical axis of described 5% catoptron (2) is provided with polarization splitting prism (4); Be vertically installed with diffraction grating (10) on the transmission optical axis of described polarization splitting prism (4) and with this optical axis; Described diffraction grating (10) ± be respectively arranged with first reverberator (8) and second reverberator (12) on the 1 order diffraction optical axis; The reflection optical axis of described polarization splitting prism (4) is provided with the one 50% spectroscopes (5); The transmission optical axis of described the one 50% spectroscopes (5) and the emergent light axis intersection point place of described first reverberator (8) are provided with the two 50% spectroscopes (6); The reflection optical axis of described the one 50% spectroscopes (5) is provided with high reflection light mirror (7); The emergent light axis intersection point place of the reflection optical axis of described high reflection light mirror (7) and described second reverberator (12) is provided with the three 50% spectroscopes (13); Be respectively equipped with second and third analyzer and first and second photelectric receiver (3,14) on the optical axis of described the two 50% spectroscopes (6) and the three 50% spectroscopes (13).

2. the rolling angle measurement device based on the diffraction grating shift technique according to claim 1, it is characterized in that, the two ends of described diffraction grating (10) are provided with in order to first fixed support (9) of fixed diffraction grating (10) and second fixed support (11), and the lower end of described first fixed support (9) and second fixed support (11) is fixed first reverberator (8) and second reverberator (12) respectively.

3. the rolling angle measurement device based on the diffraction grating shift technique according to claim 2, it is characterized in that, described diffraction grating (10) is fixed on the measurand, as sensitive element, first and second reverberator (8,12) is fixed to guarantee relative static with described diffraction grating (10) by first and second fixed support (9,10); Constituted the target reflector (102) of one by diffraction grating (10) and first and second reverberator (8,12); By two-frequency laser (1), 5% catoptron (2), first, second and third analyzer and first, second and third photelectric receiver (3,14,15), polarization splitting prism (4), first, second and third 50% catoptron (5,6,13) and high reflection light mirror (7) constitute measuring head (101).

4. according to claim 1,2 or 3 described rolling angle measurement devices based on the diffraction grating shift technique, it is characterized in that described first and second reverberator (8,12) is Si Mite prism or high reflection mirror.

5. the roll angle measurement method based on any described device of claim 1-3 is characterized in that, may further comprise the steps:

1) light beam that sends of two-frequency laser (1) is divided into two-beam through 5% spectroscope (2), and wherein folded light beam is received behind first analyzer and the 3rd photelectric receiver (15), is considered as reference signal;

2) be divided into S light and P light behind the transmitted light beam process polarization splitting prism (4) by 5% spectroscope (2) outgoing; S light is divided into two bundles through the first 50% spectroscopes (5) after polarization splitting prism (4) reflection, wherein transmitted light beam incides second analyzer and first photelectric receiver (3) is received after the reflection of the two 50% catoptrons (6), it is the reference beam of second photelectric receiver (14), wherein folded light beam incides the 3rd analyzer and second photelectric receiver (14) is received after high reflection mirror (7) and the reflection of the three 50% catoptrons (13), is the reference beam of the 3rd photelectric receiver (15); Diffraction takes place to diffraction grating (10) back in P light transmission polarization splitting prism (4) normal incidence, wherein+1 the order diffraction light beam is after first reverberator (8) reflection, with diffraction grating (10) orthogonal directions outgoing, see through that the two 50% catoptrons (6) incide second analyzer and first photelectric receiver (3) is received, it is the measuring beam of second photelectric receiver (14), in like manner, wherein-1 the order diffraction light beam is after second reverberator (12) reflection, with diffraction grating (10) orthogonal directions outgoing, seeing through that the three 50% catoptrons (13) incide the 3rd analyzer and second photelectric receiver (14) is received, is the measuring beam of the 3rd photelectric receiver (15); The reference beam that second photelectric receiver (14) receives and the interference signal of measuring beam are considered as+1 grade of measuring-signal, and the reference beam that the 3rd photelectric receiver (15) receives and the interference signal of measuring beam are considered as-1 grade of measuring-signal;

3) ± 1 grade measuring-signal, reference signal are finally counted value C by counter through comparer, counting and Acquisition Circuit respectively _{+ 1}, C _-1And C _R, by heterodyne technology measuring-signal and reference signal are carried out difference and can get Δ C _{+ 1}With Δ C _-1, data are delivered in the PC the most at last, and difference gets N again, calculates the micro-displacement S of grating according to the Doppler effect of diffraction grating, according to the geometric relationship α=S/R of small displacement S and corner, solves tested roll angle α, and wherein R is the lift-over radius.

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