CN102269582A

CN102269582A - Spatial three-dimensional angle measurement apparatus

Info

Publication number: CN102269582A
Application number: CN 201110115295
Authority: CN
Inventors: 赵斌; 马国鹭
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2011-05-05
Filing date: 2011-05-05
Publication date: 2011-12-07
Anticipated expiration: 2031-05-05
Also published as: CN102269582B

Abstract

The invention discloses a spatial angle measurement apparatus. A laser emitted by a laser light source is transmitted through a first polaroid and enters into an unpolarized splitter. A diffraction order of the laser reflected by the unpolarized splitter is enlarged by a rectangular raster, and the laser traverses through a conical lens to form non-diffracting spots; a horizontal course angle and an angle of inclination of a measured object can be calculated according to the non-diffracting spots. The laser reflected by the unpolarized splitter traverses into a second polarized splitter; and an intensity of the laser reflected by the second polarized splitter and a light intensity of the laser transmitted through the second polarized splitter are captured by a photocell, and a ratio of the former to the latter is treated with an arcsine calculation to obtain a roll angle of the measured object. According to the invention, large-scope three-dimensional spatial angle measurement is realized; besides the apparatus has characteristics of strong resistance to ambient light interference, high resolution, high precision and a compact structure, and can be widely used in equipment requiring various spatial angle measurements.

Description

A kind of space three-dimensional angle measurement unit

Technical field

The invention belongs to the spatial angle measuring technical field, be specifically related to measurement mechanism the three dimensions wide-angle.

Background technology

The main metering system of angle measurement technique has mechanical type, electromagnetic type and optics angle-measuring method.The desk-top angle measurement accuracy with electromagnetism circle magnetic-grid-type of early stage classical mechanical tooth calibration is limited to, and is difficult to realize robotization; The optics angle-measuring method has noncontact, pinpoint accuracy and high sensitivity, and especially its advantage is more remarkable when using stable LASER Light Source.

At present, the optics angle-measuring method also has photoelectric encoder method, diffraction approach, autocollimation method, optical Fiber Method, acoustooptic modulation method, circle raster method, optics internal reflection method, laser interferance method, parallel interferogram technique and loop laser method etc. except that classical optics dividing head method and polygon method.Though these methods can provide higher measuring accuracy, but based on the optical system of this design, physical construction more complicated not only, and in measuring system based on optical imagery Fundamentals of Measurement theory, because of being subjected to ambient light interference, spherical aberration and aberration etc. to influence measuring accuracy, and these optics angle-measuring methods mostly are confined to small angle range, space one dimension or two dimension angular during to spatial angle measuring under the prerequisite that guarantees measuring accuracy, so have bigger limitation in the actual application of industry.Therefore, the measurement mechanism that needs angle measurement accuracy height, angle measurement scope can measure three-dimensional perspective more greatly simultaneously satisfies requirement of engineering.

Summary of the invention

The object of the present invention is to provide the three dimensions angle measurement unit of a kind of tool, have the characteristics of strong anti-ambient light interference ability, high resolving power, high measurement accuracy and compact conformation than wide-measuring range.

A kind of space three-dimensional angle measurement unit comprises LASER Light Source, polaroid, unpolarized light splitting piece, polarization spectro sheet, rectangular raster, Conical Lenses, imageing sensor, photoelectric cell and digital information processing system;

The unpolarized light splitting piece of incident after the laser process polaroid transmission that LASER Light Source is sent; After unpolarized light splitting piece laser light reflected enlarges the order of diffraction through rectangular raster, pass Conical Lenses and form the diffraction light-free spot, imageing sensor is caught the diffraction light-free spot and is sent digital information processing system to, and digital information processing system calculates level boat angle and the angle of pitch of measurement to picture according to the diffraction light-free spot; Through the laser incident second polarization spectro sheet of unpolarized light splitting piece transmission, photoelectric cell is caught through the second polarization spectro sheet laser light reflected intensity I ₁Laser intensity intensity I with transmission ₂, and sending it to digital information processing system, digital information processing system is to I ₁With I ₂Ratio calculate the roll angle of measurement as inverse sine to picture.

Further, unpolarized light splitting piece and polarization spectro sheet are in angle of 45 degrees; Rectangular raster and unpolarized light splitting piece are in angle of 45 degrees; The baseplane of the photosurface of ccd image sensor, rectangular raster and Conical Lenses is parallel to each other; Symmetria bilateralis at the polarization spectro sheet is distributed with two photoelectric cells, and two photronic reception planes become 90 degree angles.

This method has following advantage:

Centering characteristic that 1 diffraction light-free is good and strong anti-ambient light interference ability have improved the centering precision of spot center, and the photronic light intensity linearity is very good, has guaranteed to install the measuring accuracy of the angle of pitch, pitch angle and roll angle with respect to the horizontal plane.

Based on the polarisation of light theory, the measure theory scope of roll angle was 0 °～90 ° when 2 measurements owing to roll angle were; Utilize rectangular raster that measurement range is extended to original at least 3 times, the angle of pitch, incline measurement scope can reach at least ± and 40 °, the present invention has improved the measurement range of space angle greatly when guaranteeing measuring accuracy.

3 modes by full optics have realized the measurement to the space all angles, and its compact conformation, simple, are easy to Project Realization.

Description of drawings

Fig. 1 is an embodiment of the invention structural representation;

Fig. 2 optical schematic diagram of the present invention;

Fig. 3 rectangular raster enlarges the measurement range principle schematic;

Embodiment

Below in conjunction with accompanying drawing preferred embodiment of the present invention is described in further detail.

As shown in Figure 1, realize the required concrete device of this example: transmissivity is that 75% unpolarized light splitting piece 3, transmittance are that 80% polaroid 2, transmittance are the

photoelectric cell

4 and 5 of 50% polaroid 6, Conical Lenses 7, ccd image sensor 8, rectangular raster 9, two large photosensistive surfaces, and polaroid 2 is fixed on the laser instrument 1; Unpolarized

light splitting piece

3 and 6 liang of planes of polarization spectro sheet are in angle of 45 degrees; Rectangular raster 9 also becomes 45 plane included angles of spending with unpolarized light splitting piece 3; Ccd image sensor 8 photosurfaces, rectangular raster 9 are parallel to each other with the baseplane of Conical Lenses 7; Two photoelectric cells 4 become 90 degree angles with 5 the plane of accepting, and are symmetrically distributed in the both sides of polarization spectro sheet 6.

Space three-dimensional measurement of angle principle of the present invention as shown in Figure 2.It is that 75% light splitting piece 3 is divided into two-way that laser beam behind the collimation incides transmissivity via polaroid 2.By that Shu Guangqiang that forms of light splitting piece 3 reflection a little less than, to the rectangular raster 9 expansion orders of diffraction (Fig. 3 has provided rectangular raster expansion measurement range principle schematic), via Conical Lenses 7, produce the diffraction light-free spot, catch by ccd image sensor 8, by to the calculating of diffraction light-free spot centre coordinate (wherein the computing method of spot center can with reference to " based on the diffraction light-free of annulus filtering fixed in an algorithm " literary composition), just can correspond to angle surface level in and the pitch angle of apparatus of the present invention with respect to laser beam.

That stronger road parallel laser of light splitting piece 3 light intensity is crossed in transmission, and to be transmitted through transmittance be behind 50% the polarization spectro sheet 6, and a part is received by photoelectric cell 4, and another part is received by photoelectric cell 5; The laser intensity that

photoelectric cell

4,5 will shine on it is converted to corresponding electromotive force, is respectively I ₁, I ₂The relations I corresponding with roll angle θ according to light intensity ₂/ I ₁=sin θ just can calculate its roll angle.

Based on diffraction light-free spot centre coordinate is to calculate by the image process method interpolation fitting to get, be subjected to ccd image sensor light intensity linearity operation interval to influence very little, and the interference performance of its strong anti-surround lighting of diffraction light-free, rectangular raster widen the angle measurement scope time also can guarantee the measuring accuracy at horizontal angle and angle of inclination; Photronic photosurface is big, and light intensity linearity working range is wide, and roll angle is measured corresponding light intensity and calculated simply, and not only measurement range is big to make roll angle, and the measuring accuracy height.

The foregoing description is preferred embodiment of the present invention; this apparatus structure compactness; each the space angle scope that can survey is up to 90 degree; measuring accuracy reaches a millivolt degree; but unintelligible for this example be unique selection of the present invention; be to realize the present invention by the relative angle that changes different assemblies under the same idea of the present invention, all belong to protection category of the present invention.

Claims

1. a space three-dimensional angle measurement unit comprises LASER Light Source, polaroid, unpolarized light splitting piece, polarization spectro sheet, rectangular raster, Conical Lenses, imageing sensor, photoelectric cell and digital information processing system;

The unpolarized light splitting piece of incident after the laser process polaroid transmission that LASER Light Source is sent; After unpolarized light splitting piece laser light reflected enlarges the order of diffraction through rectangular raster, pass Conical Lenses and form the diffraction light-free spot, imageing sensor is caught the diffraction light-free spot and is sent digital information processing system to, and digital information processing system calculates level boat angle and the angle of pitch of measurement to picture according to the diffraction light-free spot; Through the laser incident second polarization spectro sheet of unpolarized light splitting piece transmission, photoelectric cell is caught through the second polarization spectro sheet laser light reflected intensity I ₁Laser intensity intensity with transmission I ₂, and sending it to digital information processing system, digital information processing system is right I ₁With I ₂Ratio calculate the roll angle of measurement as inverse sine to picture.

2. space three-dimensional angle measurement unit according to claim 1 is characterized in that, unpolarized light splitting piece and polarization spectro sheet are in angle of 45 degrees; Rectangular raster and unpolarized light splitting piece are in angle of 45 degrees; The baseplane of the photosurface of ccd image sensor, rectangular raster and Conical Lenses is parallel to each other; Symmetria bilateralis at the polarization spectro sheet is distributed with two photoelectric cells, and two photronic reception planes become 90 degree angles.

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