Accept rice measures precision grating sensor to consider to sum up

Grating technology is nicety measures one of main measures. It is offerred with objective form measure fiducial, the quartz that can introduce small hot coefficient of expansion already or 0 expand the material such as glass serves as matrix, also can collect the glass that appliance has and the material hot coefficient of expansion such as steel is close to very much or metallic stuff to serve as matrix, use stability reliable, zero shift is little. Accordingly, the domain is measured in rice of big displacement accept, grating accept rice measures measure to have wide applied perspective. One, accept rice measures precision grating to sensor studies and develop 　 1.

The Mo Er stripe that when using two grating alternate to close, forms undertakes 1 pair of grating measure systematic double grating metrical. Graph 1 it is tall line several pairs of grating measure systematic light road principle graph, structure of this kind of grating basically includes prism of illuminant, referenced grating, rear sight grating, pyramid and 3 photoelectricity detector, if its job principle pursues 2, process of job of its light road is as follows. (1) illuminant launchs the transmission of A of beam of light that go out to consult diffractive light beam produces after grating too, show 1 class of ± is diffractive only in the graph smooth B and B. (2)B and B two bundles of diffractive light and pyramid prism, rear sight grating uses Littrow to be installed from collimation, each Shu Guangdou above all smooth canopy of incident staff guage, the diffraction of the 1st class after be being reflexed next enters person pyramid prism solely. The diffraction of the 1st class of B of beam of light and B is C, C respectively solely. (3) the reflex D of CC, d goes out from pyramid prism shoot, and again the person shoots rear sight grating, right now with former reflex C, c produced parallel to engrave side direction displacement of groove at grating. (4)D, the smooth E of diffraction of the 1st class of D, e weighs new personality to shoot referenced grating, arise respectively piece shoot alignment, e, e is the same point that symmetrical person shoots referenced grating, and their piece shoot alignment also coincide is together. (5) is being used actually in, photoelectricity detector 1, 2, 3 receive 3 a F ejaculation light, G, H. Taking 3 photoelectricity to change the end of signal is to move, for ancient bronze mirror of circuit of follow-up computation fractionize to use. The taller than be equal to two of 2 line that this system makes consumed canopy invariable counts grating, by distinctive Shuang Guangpeng the structure realized optics 4 fractionize, make optical displacement resolution achieves the 1/4 that grating bar is apart from rear sight. Add times taller electronic fractionize, make final displacement resolution achieves 1nm, its measure limits to be equal to the length of rear sight smooth canopy. 1.

2 show off grating light energy to differ in smooth canopy spectrum class second the allocation that go up depends on the geometrical figure that grating cuts groove. Want to change grating to cut section plane figure of groove only, make those who if the graph is shown 3 times,become is dentate, can make diffractive major light energy by 0 class advocate great the class that moves to need to place second on, distributinging circumstance go-between shoots the light intensity that overcame transmission grating thereby smooth major energy is centered in 0 class diffraction (without chromatic dispersion) advocate great on, and in other class second, especially more advanced second glazing is strong very minor weak point. The grating that has this kind of character is called show off grating. It is in the directional transmission smooth canopy that the graph shows 3 times, be equivalent to by the side of toothed length " diffraction is seamed " , short edge is not pervious to light " seam interval " , n is average grating surface normal, n is the normal of long side. Set a person to shoot light to be θ I to the person angle of fire of grating surface, the person angle of fire that seams to diffraction is α , the diffractive horn to grating surface is its some diffraction light θ K, and the develop angle of fire that seams to diffraction is β , θ B. It is the included angle of N of average grating surface normal and the normal N that grow a border, the 　 of B of θ of I- of θ of ＝ of relation 　 α that has as follows between these angle 　 of B of θ of K- of θ of 　 β ＝ pursues 4 it is the principle picture that displays grating one kind to measure an orgnaization, this orgnaization by demonstrative grating G1, (show off grating) comprise with metric grating G2. Adjust the person angle of fire of incident beam of light accurately, make energy of light of two diffractive stage equal, and symmetrical between the space of two grating transmission. In the course metric grating after the 2nd diffraction, give α ejaculation light, α . Pass lens, in 4 quadrant photoelectric cell D receives the be concerned with on the face to form Mo Er stripe. Can prove to move relatively when two grating when the bar of a fine grating is apart from, two bundles of diffractive light are phasic poor change 2 π , that is to say, interference stripe light and shade changes a cycle, and the bar of this kind of change and metric grating is apart from have nothing to do. Because show off the bar of grating to be apart from a lot of times smaller than metric grating, so systematic resolution rises greatly. This measures orgnaization and probe of gas surplus slideway and ruby to be able to be comprised exceed accurate measuring instrument, its measure limits to be able to amount to 0~100mm, resolution can amount to 1nm. 1.

Of the 3 systematic errors that the grating accept rice that is based on an error to amend a technology measures a system to pass pair of grating to measure detect, depart and amendatory method, can raise grating side substantially to measure systematic accuracy, make from micron, inferior micron grade level takes level of grade of person pay rice, measure in order to realize grating accept rice, its key technology is as follows. 1.

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1 error detects graph the 5 structural block diagram that are error testing system. Rice of smooth canopy accept measures system and laser interferometer to bind together through accurate slideway, measure axes park same go up to accord with Abbe principle in order to assure point-blank. Choose synchronous trends to detect means, the measurement that measures system and laser interferometer to rice of smooth canopy accept data, in the sampling pulse that by computer pilot synchronism sampling pulse generator gives out spark sampling of similarly hereinafter hour, pass the computer to undertake handling. 1.

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The error fraction that rice of accept of grating of 2 errors depart measures a system is sum of errors of error of periodic accumulative total, fractionize random error 3 kinds. Detect the result that data also is mixture overlay of component of these 3 kinds of errors. To undertake systematic error is compensated, must detect before two errors from total error the depart in the result comes out. Component of these 3 kinds of errors has different spectrum character, the method that can establish foliaceous commutation and disperse spectrum analysis easily through teach will realize error depart; Detect the composition with the fundamental frequency in data and consistent frequency of space of Mo Er stripe is fractionize error; After its depart comes out, have the low wave that connect filter to the rest part, the random error with high frequency take out, get error of periodic accumulative total namely. 1.

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3 errors amend grating accept rice to measure systematic error to amend strategy to have the following kinds. (1) returns to amend grating accept rice to measure systematic error amendatory to return to be amended is to point to in full span all locally, use identical correction parameter to undertake systematic error is amended, namely to error of periodic accumulative total, with same undertake linear is amended point-blank; To fractionize error, use same a fractionize error correction curve. The computational formula that grating measures is E of ＋ of NxW of 　 X ＝ (1) in 　 type, x is the displacement quantity before grating is amended, n is the computation of the whole periodicity of the signal of Mo Er stripe that carry to be worth, w represents the constant of cycle of space of signal of Mo Er stripe, e is the fine heft that fractionize circuit reachs. The fixed deflection amount that sets error of periodic accumulative total is δ , the error amends coefficient to be β , fractionize error curve uses function ERR (E) will express, the displacement after be being amended measures the computational formula of Xb to because grating is measured,be is to be measured relatively, and fixed cost is in returning to revise a law, reason can make δ is 0, and do not affect measure an outcome, the computational formula that puts in one correction law 's charge then turns into full span returns to amend those who imply correction numerical value to get with measure the position to have nothing to do currently, can apply to the grating that does not have absolutely null to survey a system, apply to rice of accept of high speed grating to survey a system especially. Its defect is to be in the system with systematic older error, the error is amended not quite complete, correction precision is not tall. (2) section correction section is amended even if according to its full span error feature cent is a certain number of paragraph, each paragraphs have his correction parameter, press located paragraph different the correction that undertakes differring, namely to error of periodic accumulative total, each paragraphs undertake correction by respective correction function; To fractionize error, each paragraphs of fractionize error that has oneself amends a curve. The computational formula of section correction law is type in, ERR(k, e) it is K paragraph β of fractionize error function (K) is K δ of; of coefficient of compensation of error of accumulative total of Duan Zhou period (K) is K paragraph the fixed deflection value of error of periodic accumulative total. The advantage of section compensation method is count enough a long time when section, can undertake accurate correction to systematic error. Its defect is to ask to measure a system to have absolutely null, require data of form of memory of many storage space, influence system whole measures speed. (3) mixes correction above two kinds of correction methods, can use alone already, OK also across mixes with the special requirement that will get used to different situation, this mixes namely amend. Mix amend can measuring obtain between precision and speed some kind is eclectic. 1.

Accept rice measures the 4 grating that are based on Mo Er stripe 2 times systematic construction of system is shown 6 times like the graph. In the graph, demonstrative grating B and demonstrative grating C are fixed in same measure base on feet, α of rear sight grating is mixed with demonstrative grating B respectively demonstrative grating. Produce I-II of signal of two groups of Mo Er stripe and I-II, use lens 5 with the 6 mobile direction that will adjust Mo Er stripe. Lens 7, 8 and 12, 13 respectively will one stripe signal I-II mixes Cimoer I-II is contractible, so that have Mo Er of full adequate amount,stripe is interfered again form Mo Er stripe 2 times. When moving relatively along α of rear sight grating when demonstrative grating B and demonstrative grating C, signal of two groups of when demonstrative grating B and demonstrative grating C part and α of rear sight grating arises Mo Er stripe, through lens 5 and 6 make the mobile way of signal of two groups of Mo Er stripe opposite. Signal of two groups of Mo Er stripe passes lens 7, 8 and 12, 13 and prism 9, 10 processing, component will be received in photoelectricity 11 on interference produces Mo Er stripe 2 times, through be opposite 2 times signal of Mo Er stripe undertakes electronic fractionize, can obtain taller fractionize to measure precision. The course emulates computation, grating sensor resolution is achieved 5.

40x10-10m, measure precision to reach accept rice level. 2, the crucial technology 　 that grating accept rice measures 2.

1 be based on new-style the grating accept rice that measures rice of principle grating accept to measure systematic research to be based on diffractive and optical principle surveys a system, measure range lesser, the system is complex, in big displacement the application in measuring an instrument is restricted. The rice of metric grating accept that is based on an error to amend a technology surveys a system, correction program of depart of error demarcate, error, error is complex, and slashing to measuring an environment to ask. Measure range to satisfy the need that the accept rice with strong capability of big, interference rejection measures an instrument, must break through somewhat on the research that measures a principle. The accept rice that we are based on principle of Mo Er stripe 2 times to consider measures precision metric grating sensor, be calculated through theory and emulate, can achieve accept rice class to measure precision. But, turn theory into real product, need to study further in respect of the following and crucial technology: (1) accept rice measures precision grating sensor to grating is designed deputily and be developed; (2) the research that 2 times Mo Er stripe forms the light energy in the process to concern evenly; (the character that 3) photoelectricity is sent and accepts component matchs and optimize a design; (4) the dynamic character of photoelectricity system considers to wait. 2.

The develops nicety mechanical system of 2 accurate and mechanical systems is implementation what grating accept rice measures is important assure. How be designed and make the journey be in millimeter class or a few millimeter even the suits accept rice class to measure precision to need actuating device of hundreds of millimeter and slideway, still be the technical difficult problem that at present need solves. 2.

Processing of 3 photoelectricity signal and rice of accept of fractionize technology grating are measured in high frequency answer with existence is contradictory between high resolution, be necessary to consider to have more high frequency rate to answer, the technology of fractionize of Mo Er stripe that tall fractionize portion counts. Accept rice measures grating to ask to have high fractionize portion multiple not only, and requirement fractionize is even, make its have tall fractionize precision and stronger error to amend latent capacity. 2.

4 errors depart and error amend grating to measure is serve as with objective measure fiducial, although be in treatment, assemble, adjust, a lot of step were taken in the numerous link such as signal processing, but still still have factor of a lot of errors inevitable, the score error that is like grating, linearity error of slideway, electron yuan of parts of an apparatus nonlinear the error. Measure the error measurement to accept rice class by what they cause for the system, remain cannot of oversight. Apply an error adequately to amend a technology to assure the accuracy traceability of accept rice class of the system, it is one of crucial technologies that rice of implementation grating accept measures. 2.

The 5 progress that measure ambient conditions to measure a technology as accept rice, strict also to the requirement of working environment. The resolution that grating accept rice surveys a system is high, very sensitive to environmental change, working environment already became very main factor to the influence of accuracy. Build the job that gets used to grating accept rice to measure so environment or undertaking environmental error is amended also is a task that solves urgently. CNC Milling