CN1304880C - Long distance bidimension photoelectric self collimating device for drift amount target feedback control and its method - Google Patents

Abstract

The invention relates to a long-distance two-dimensional photoelectric self-collimation device and method for feedback control of a drift target. The device includes a two-dimensional photoelectric self-collimating light tube, a computer, a two-dimensional beam deflecting device, and a drift monitoring device, and also includes a spectroscopic target detector, which is located between the two-dimensional beam deflecting device and the drift monitoring device. In between, the spectroscopic target detector separates and feeds back the angular drift component feedback beam with the same characteristics as the measurement beam while acquiring the measurement signal of the two-dimensional small angular variation. The angular drift is monitored in real time. The computer controls the two-dimensional beam deflection device in real time according to the angular drift monitored by the drift monitoring device. Angular drift, while increasing the measurement distance of the two-dimensional photoelectric autocollimator, improves the measurement stability.

Description

Long-distance two-dimensional photoelectric self-collimation device and method for drift target feedback control

technical field

The invention belongs to the technical field of precision instrument manufacturing and precision testing and measurement, and in particular relates to a long-distance high-precision two-dimensional photoelectric self-collimation measurement device and measurement method based on drift target feedback control technology to compensate the angular drift of light beams in real time.

Background technique

With the continuous improvement and improvement of measurement technology, the development of modern high-precision measurement technology and azimuth targeting and tracking system has put forward higher and higher requirements for the measurement accuracy of small angles. Photoelectric autocollimator plays an irreplaceable role in small-angle precision measurement, high-precision aiming and positioning. It can be used as a component of optical measuring instruments such as goniometers and optical comparators, and can also be used alone in measuring instruments for optical Measurement, assembly and adjustment of aerospace instruments and attitude measurement of military aircraft.

In high-precision small-angle measurement, the laser beam is often used as a measurement standard and widely used in ultra-precision processing equipment and measurement equipment due to its good single directionality, high brightness and high stability. Many research institutes have developed Photoelectric autocollimator using laser light source and high-precision CCD image sensor to measure two-dimensional angles (1. Wu Xiuli. Laser Autocollimator. Optical Electromechanical Information. 1994, Issue 08: 11-13; 2. Jiang Benhe, Chen Wenyi, Hu Wenfei, Hu Qingrong. A small-angle measurement system using laser alignment and CCD detection. Laser and Infrared. 1998, 28(4): 233-234+243; 3. Lin Yuchi, Zhang Ping, Zhao Meirong, Hong Xin. Field Semiconductor laser autocollimator used. Aeronautical Precision Manufacturing Technology. 2001, 37(3): 35-37; 4. Zhang Yaoyu, Zhang Minghui, Qiao Yanfeng. Research on a high-precision CCD laser autocollimation measurement system. Optoelectronics Laser. 2003, 14(2): 168-170; 5. Ma Fulu, Zhang Zhili, Zhou Zhaofa. Single linear array CCD straightness collimator based on M-type reticle. Optical Technology. 2002, 28(3): 224-225 +227).

For photoelectric autocollimators whose measurement uncertainty is better than 0.5″, the measurement distance is usually less than 6m (1. Wu Jinxie. Geometric Quantity Precision Measurement Technology. Harbin Institute of Technology Press. September 1989; 2. Germany MLLER- Chinese operation manual of ELCOMAT vario dual-axis autocollimator of WEDEL company. 2004; 3. Chinese operation manual of SZY-99 digital display autocollimator of Jiujiang Precision Testing Technology Research Institute, No. 6354 Research Institute of China Shipbuilding Industry. 2004; 4. UK Taylor Hobson company TA51, DA20, DA400 type optical autocollimator Chinese operation manual.2002).In long-distance applications, the angular drift of the laser beam is the main source of photoelectric autocollimator measurement error. Cause beam drift The main reasons are: (1) the angular drift of the beam caused by the deformation of the reflector in the laser resonator; (2) the random jitter of the atmospheric air flow in the beam propagation path causes the random disturbance of the laser beam and the change of the atmospheric gradient refractive index. Bending, etc. Theoretical analysis shows that light bending is proportional to the square of the distance, and random jitter is proportional to the 1.5th power of the distance. As the distance increases, the random jitter of the atmospheric airflow in the beam propagation path causes the random disturbance of the laser beam The impact of light bending caused by the change of the atmospheric gradient refractive index will far exceed the angular drift of the beam caused by the deformation of the mirror in the laser resonator, so it is more difficult to improve the collimation accuracy. In the long-distance laser collimation system, the wave The spatial connections of interference and diffraction fringes produced by band plates, phase plates, binary optical devices, double slits, etc. are used as reference lines, and they are not sensitive to drift to achieve the purpose of collimation. Typical methods are Phase plate diffraction collimation method, binary optical collimation method, double-beam compensation collimation method, etc. The collimation accuracy of these methods is generally in the order of 10 ^-6 rad, that is, about 0.2″. (1. Wan De'an. Laser benchmark high-precision measurement technology. National Defense Industry Press. June 1999; 2. Fang Zhongyan, Yin Chunyong, Liang Jinwen. Research on high-precision laser alignment technology (1). Aeronautical measurement technology. 1997 , 17(1): 3-6; 3. Rao Ruizhong, Wang Shipeng, Liu Xiaochun, Gong Zhiben. Experimental Research on Laser Beam Drift in Turbulent Atmosphere. China Laser. 2000, 27(11): 1011-1015; 4. Yang Youtang, Zeng Lijiang , Yin Chunyong. Application of Adaptive Noise Removal Technology in Laser Collimation. Journal of Instrumentation. 1995, 16(4): 370-374).

In the data acquisition and processing of two-dimensional photoelectric autocollimator, due to the influence of beam drift, if the spot center positioning method is used, the spot center received by the receiver will drift with the beam drift; if the contour center positioning method is used, due to beam drift , the misalignment between the energy center of the light spot received by the receiver and the geometric center of the contour causes the deviation of the contour center, which directly produces the positioning deviation of the contour center. If the angle drift is not corrected or compensated, it will directly feed back the angle measurement deviation caused by the measurement results of small angles, resulting in poor repeatability of instrument data, poor stability, and even drifting of the light spot out of the receiving field of view, affecting the instrument normal work. To further improve the measurement stability and measurement accuracy, it is difficult to achieve only by improving the collimation accuracy of the beam itself, no matter from the existing technology or the manufacturing level.

The closed-loop feedback control technology provides an effective technical way to eliminate or compensate the angle measurement deviation caused by the angle drift and realize high-precision small-angle measurement. In order to improve the directional stability of the laser beam, many experts and scholars at home and abroad have proposed many laser alignment methods based on closed-loop feedback control technology for different applications (1. Zhao Weiqian, Tan Jiubin, Ma Hongwen, Zou Limin. Drift feedback control method Laser alignment method. Acta Optics Sinica. 2004, 24(3): 373-377; 2. Yu Daren, Zhang Zhiqiang, Xu Jiyu, Su Jiexian. Optical path automatic compensation method for interference in laser measurement. Acta Instrumentation. 2003 , 24(2): 123-126; 3. Yu Dianhong, Guo Yanzhen. A method to improve laser alignment accuracy. Petroleum Instruments. 1999, 13(6): 18-20; 4. Li Yan, Meng Xiangwang, Zhang Enyao . A new type of laser scanning large workpiece hole-hole coaxiality measuring instrument. Laser and Infrared. 2000, 30(5): 280-282).

In practical application, it can be seen that although the above measurement scheme suppresses the angular drift of the beam to a certain extent, the above measurement scheme is only for the application of a specific laser line reference, and the control object is the center position of the laser beam. However, in the practical application of two-dimensional photoelectric autocollimator, especially in long-distance applications, it is required to introduce feedback to control the angular drift of the laser beam and at the same time accurately measure the two-dimensional small angle change. The object of feedback control is the two-dimensional small-angle change that needs to be measured by the two-dimensional photoelectric autocollimator. The unknown of the controlled object directly makes it impossible to introduce feedback control in the measurement process of the two-dimensional photoelectric autocollimator. The angular drift of the beam is not eliminated during the measurement process, and the final mixture causes angle measurement deviation in the measurement results, resulting in poor measurement stability and repeatability of the photoelectric autocollimator in long-distance applications, and it is difficult to further improve the measurement uncertainty , which greatly limits the application range of photoelectric autocollimators, which is also an important problem that cannot be solved in the actual application of photoelectric autocollimators.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the above-mentioned existing photoelectric autocollimator measurement method, and to provide a long-distance two-dimensional photoelectric autocollimation device and method for drift target feedback control. Simultaneous separation of two-dimensional small angular variation measurement signals and feedback back to the angular drift component feedback beam with exactly the same characteristics as the measurement beam, including the drift monitoring device of the focusing objective lens and four-quadrant detector The angular drift of the angular drift component feedback beam The computer can control the two-dimensional beam deflection device in real time according to the angular drift monitored by the drift monitoring device, adjust the measuring beam in the opposite direction of the angular drift, and suppress and eliminate the coupling of the measuring beam in the measuring signal. Angular drift, dynamically compensates the angle measurement error caused by the angular drift of the beam, has a long monitoring distance, and has high monitoring sensitivity to the angular drift, which can significantly improve the measurement distance, measurement stability and measurement accuracy of the two-dimensional photoelectric autocollimator .

The technical solution adopted in the present invention is: a long-distance two-dimensional photoelectric self-collimation device for feedback control of a drift target, including a two-dimensional photoelectric self-collimation light tube, a computer, a two-dimensional beam deflection device, and a drift monitoring device , the two-dimensional photoelectric self-collimating light tube is composed of a laser light source, a reticle, a beam splitter, a CCD image sensor and a collimating objective lens placed in sequence, and the drift monitoring device includes a focusing objective lens that is fixedly connected and a four-quadrant detector, the two-dimensional beam deflection device is composed of a piezoelectric ceramic drive power supply, a piezoelectric ceramic displacement device, a two-dimensional micro-displacement worktable and a deflection mirror, and also includes a spectroscopic target detector. The target detector is located between the two-dimensional beam deflection device and the drift monitoring device. The spectroscopic target detector separates and feeds back the angular drift component that is exactly the same as the measurement beam characteristic while obtaining the measurement signal of the two-dimensional small angle variation. The feedback beam, the drift monitoring device monitors the angular drift of the angular drift component feedback beam in real time, and the computer controls the two-dimensional beam deflection device in real time according to the angular drift monitored by the drift monitoring device. The orientation is adjusted to suppress the angular drift of the measurement beam coupled into the measurement signal.

The spectroscopic target detector is composed of half surface of the inclined working surface of the rectangular prism coated with a spectroscopic film, and the measuring beam is incident on the working surface coated with the spectroscopic film.

The spectroscopic target detector is composed of half surface of the inclined working surface of the corner cube prism coated with a spectroscopic film, and the measuring beam is incident on the working surface coated with the spectroscopic film.

The spectroscopic target detector is composed of two oppositely placed pentagonal prisms, one of which is coated with a spectroscopic film on the working surface, and the measuring beam is incident on the working surface of the pentaprism coated with the spectroscopic film.

The spectroscopic target detector is composed of two right-angle prisms placed opposite to each other. One of the vertical working surfaces of one right-angle prism is coated with a spectroscopic film, and the measuring beam is incident on the vertical working surface of the right-angle prism coated with a spectroscopic film.

The present invention also provides a long-distance two-dimensional photoelectric self-collimation method for drift target feedback control, comprising the following steps:

1. The two-dimensional photoelectric self-collimating light tube emits a measuring beam;

2. The spectroscopic target detector receives the measuring beam and separates it into reflected beam and transmitted beam;

3. The reflected beam acquires the two-dimensional small-angle variation of the spectroscopic target detector and is received by the CCD image sensor to become a measurement signal;

4. The transmitted beam separates the angular drift component feedback beam with the same characteristics as the measurement beam, and feeds it back to the drift monitoring device. After being received by the four-quadrant detector through the focusing objective lens, the angular drift of the angular drift component feedback beam is monitored:

$\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arctan</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;d</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>$

Wherein: ε is the angular drift of the angular drift component feedback beam, Δd is the displacement of the focus center of the angular drift component feedback beam from the center of the four-quadrant detector, and f ₀ is the focal length of the focusing objective lens;

5. The computer controls the two-dimensional beam deflection device in real time according to the angular drift of the angular drift component feedback beam monitored by the drift monitoring device, so that the measuring beam is adjusted in the opposite direction of the angular drift. The adjustment amount is:

φ＝ε

Where: φ is the adjustment amount of the two-dimensional beam deflection device to the spatial angle of the beam, and ε is the angular drift of the angular drift component feedback beam;

6. Repeatedly adjust according to step 3 and step 4 to suppress and eliminate the angular drift of the measurement beam coupled in the measurement signal in real time, and accurately measure the change of the two-dimensional small angle of the spectroscopic target detector from the measurement signal:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="d"\; filenames="C20051008985200211.png"\; state="\{\{state\}\}">d</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

Here: θ is the variation of the two-dimensional small angle of the spectroscopic target detector, d ₁ is the variation of the spot center position formed by the measurement signal on the CCD image sensor, and f is the equivalent focal length of the collimating objective lens.

The present invention has following characteristics and good effect:

1. Using a novel spectroscopic target detector to improve the optical measurement system, the angular drift of the beam is separated from the two-dimensional small angle change of the spectroscopic target detector, and the angular drift component that is exactly the same as the measurement beam characteristics is obtained in real time The feedback beam is fed back to the drift monitoring device, and the angular drift of the angular drift component feedback beam is monitored in real time by the four-quadrant detector, which is one of the innovations different from the existing photoelectric self-collimation measurement technology;

2. In the design, the random disturbance of the laser beam caused by the random jitter of the atmospheric airflow in the beam propagation path and the influence of the light bending caused by the change of the atmospheric gradient refractive index will cause the angular drift of the laser beam, and the angular drift of the beam is in The measurement beam and the angular drift component feedback beam change simultaneously, and the computer controls the two-dimensional beam deflection device in real time according to the angular drift of the angular drift component feedback beam monitored by the drift monitoring device, so that the measurement beam moves in the direction opposite to the angular drift. Adjustment can completely suppress and eliminate the angular drift of the measurement beam coupled in the measurement signal, which is the second innovation point different from the existing photoelectric self-collimation measurement technology;

3. This design scheme introduces closed-loop feedback control technology while accurately measuring the two-dimensional small angle variation. Adding a spectroscopic target detector, a drift monitoring device and a two-dimensional beam deflection device in the optical path can dynamically compensate the deviation of the beam. The angle measurement error caused by the angular drift solves the problem of poor measurement stability caused by the angular drift of the beam in long-distance applications, and even drifts out of the receiving field of view of the instrument. The measurement stability is improved at the same time as the distance, which meets the needs of long-distance high-precision two-dimensional small-angle measurement, and the longer the distance, the more significant the accuracy improvement, high reliability, and strong practicability.

Description of drawings

Fig. 1 is the structural representation of device of the present invention;

Fig. 2 is a structural schematic diagram of the split-type target detector in the device of the present invention obtaining a two-dimensional small angular variation and simultaneously separating and obtaining an angular drift component feedback beam having the same characteristics as the measuring beam;

Fig. 3 is the measurement schematic diagram of the angular drift of the angular drift monitoring device monitoring the angular drift component feedback beam in the device of the present invention;

Fig. 4 is a structural schematic diagram of real-time feedback control of the angular drift of the measuring beam by the two-dimensional beam deflection device in the device of the present invention;

Fig. 5 is the structure schematic diagram of the drift amount monitoring device that is made up of focusing objective lens and four-quadrant detector fixed connection in the device of the present invention;

Fig. 6 (a) is that the spectroscopic type target detector in the device of the present invention is made of the semi-surface plating spectroscopic film of the inclined working surface of the corner cube, and the structural representation of the incident light beam by the half working surface of the coating spectroscopic film;

Fig. 6 (b) is that the spectroscopic target detector in the device of the present invention is made of two oppositely placed pentagonal prisms, wherein the working surface of a pentagonal prism is coated with a spectroscopic film, and the measuring beam is incident on the working surface of the pentaprism coated with a spectroscopic film Schematic diagram of the structure;

Fig. 6 (c) is that the spectroscopic target detector in the device of the present invention is made of two right-angled prisms placed oppositely, wherein a vertical working surface of a right-angled prism is coated with a spectroscopic film, and the measuring beam is formed by the vertical direction of the right-angled prism coated with a spectroscopic film. Schematic diagram of the structure incident on the working surface.

Detailed ways

The long-distance two-dimensional photoelectric self-collimation device and measurement method based on the drift target feedback control technology of the present invention will be described in detail below in conjunction with the accompanying drawings:

As shown in Figure 1, the device of the present invention is composed of a laser light source 2, a reticle 3, a beam splitter 4, a CCD image sensor 5, a two-dimensional photoelectric self-collimating light tube 1 composed of a collimating objective lens 6, and a four-quadrant detector. 8. A drift monitoring device composed of a focusing objective lens 9 and a deflection mirror 10 7, a spectroscopic target detector 11, a computer 12, a piezoelectric ceramic drive power supply 13, a piezoelectric ceramic displacement device 14, and a two-dimensional micro-displacement workbench 15 and a two-dimensional beam deflection device 17 composed of a deflection mirror 16 and the like. The path of its light is as follows:

The laser beam emitted by the laser light source 2 of the two-dimensional photoelectric self-collimating light pipe 1 illuminates the reticle 3 at the focal point of the collimating objective lens 6, passes through the beam splitter 4, and after the collimating objective lens 6 converges, passes through the two-dimensional beam After being reflected by the deflection device 17, it is incident on the spectroscopic target detector 11 placed on the measured object. The spectroscopic target detector 11 divides the incident beam into two beams: the reflected beam obtains the two-dimensional small angle change of the spectroscopic target detector 11 Finally, after being reflected by the two-dimensional beam deflection device 17, it is converged by the collimating objective lens 6, and is imaged on the CCD image sensor 5 after being reflected by the beam splitter 4, and becomes a measurement signal; the transmitted beam becomes an angular drift component exactly the same as the measurement beam characteristic The feedback light beam is fed back to the drift monitoring device 7, reflected by the deflection mirror 10, focused by the focusing objective lens 9, and then received by the four-quadrant detector 8 located at the focal plane of the focusing objective lens 9 to separate and monitor the angular drift component feedback beam. angular drift. The computer 12 controls the two-dimensional beam deflection device 17 in real time according to the angular drift of the monitored angular drift component feedback beam, and adjusts the spatial angle of the beam, so that the measuring beam is adjusted in the direction opposite to the angular drift, and the monitoring and adjustment are repeated. steps, the angular drift of the measurement beam coupled in the measurement signal can be suppressed and eliminated in real time. From Figure 1 and Figure 2, combined with the principle of geometric optics and optical self-collimation, the variation of the two-dimensional small angle of the spectroscopic target detector 11 can be accurately measured through the measurement signal:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="d"\; filenames="C20051008985200211.png"\; state="\{\{state\}\}">d</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

Here: θ is the variation of the two-dimensional small angle of the spectroscopic target detector 11, _d is the variation of the spot center position formed by the measurement signal on the CCD image sensor 5, and f is the equivalent focal length of the collimating objective lens 6.

Obtain the two-dimensional small angular variation through the spectroscopic target detector 11 and simultaneously separate the angular drift component feedback beam with the same characteristics as the measurement beam, and monitor the angular drift of the angular drift component feedback beam by the drift monitoring device 7 As shown in Figure 2 and Figure 3, the center of the photosensitive surface of the four-quadrant detector 8 that monitors the angular drift of the angular drift component feedback beam in the drift monitoring device 7 is located at the focal point of the focusing objective lens 9, when the measuring beam produces When the angular drift ε, the angular drift component feedback beam is focused on the focal plane of the focusing objective lens 9 and produces a displacement Δd, thus monitoring the angular drift of the angular drift component feedback beam is:

$\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arctan</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;d</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>$

Where: ε is the angular drift of the angular drift component feedback beam, Δd is the displacement of the focus center of the angular drift component feedback beam from the center of the photosensitive surface of the four-quadrant detector 8, and _f0 is the focal length of the focusing objective lens 9.

The structural diagram of the real-time closed-loop feedback control of the angular drift of the measuring beam by the two-dimensional beam deflection device 17 is shown in FIG. The driving accuracy is obtained by using a two-dimensional beam deflection device 17 composed of a piezoelectric ceramic drive power supply 13, a piezoelectric ceramic displacement device 14, a two-dimensional micro-displacement worktable 15 and a deflection mirror 16, and the computer 12 monitors it according to the drift monitoring device 7. The angle drift component feeds back the angular drift of the beam to control the two-dimensional beam deflection device 17 in real time to adjust the spatial angle of the beam, and the adjustment amount is:

φ＝ε

Wherein: φ is the adjustment amount of the spatial angle of the beam by the two-dimensional beam deflection device 17, and ε is the angular drift of the angular drift component feedback beam monitored by the four-quadrant detector 8; the computer 12 is opposite to the measuring beam according to the angular drift Direction adjustment, the two-dimensional beam deflection device 17 has a corner resolution of better than 0.002″, and the corner range is greater than 2″. Repeated steps of monitoring and adjustment can suppress the angular drift of the measuring beam coupled in the measuring signal to 0.01 in real time In the range of ″, the measurement distance of the two-dimensional photoelectric autocollimator is improved while ensuring high-precision two-dimensional small-angle measurement.

Referring to FIG. 5 , the drift monitoring device 7 in the device of the present invention can be composed of a four-quadrant detector 8 fixedly connected to a focusing objective lens 9 , and the four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 .

Referring to Fig. 6 (a), the spectroscopic target detector 11 in the device of the present invention can be made of half surface coating spectroscopic film of the inclined working surface of corner cube prism 18, and measuring beam is incident by coating half working surface of spectroscopic film.

Referring to Fig. 6 (b), the spectroscopic target detector 11 in the device of the present invention can be made of two pentagonal prisms 19 and 20 placed oppositely, wherein the working surface of a pentagonal prism 20 is coated with a spectroscopic film, and the measuring beam is coated with a spectroscopic film. The working surface of the pentaprism 20 is incident.

Referring to Fig. 6 (c), the spectroscopic target detector 11 in the device of the present invention is made of two rectangular prisms 21 and 22 placed oppositely, wherein a vertical working surface of a rectangular prism 22 is coated with a spectroscopic film, and the measuring beam is coated with a spectroscopic film. The film is incident on the perpendicular working surface of the rectangular prism 22 .

The method described in the present invention is described in detail below:

The present invention also provides a measurement method for a long-distance two-dimensional photoelectric self-collimation device based on the drift target feedback control technology, and the measurement method includes the following steps:

1. First adjust the drift monitoring device 7 to ensure that the center of the photosensitive surface of the four-quadrant detector 8 is located at the focal point of the focusing objective lens 9. After the adjustment, the drift monitoring device 7 should be fixed with the two-dimensional photoelectric self-collimating light tube 1 Connect, and then calibrate the two-dimensional photoelectric self-collimation device 1, after the calibration is completed, the drift monitoring device 7 will not be adjusted during use;

2. The laser beam emitted by the laser light source 2 of the two-dimensional photoelectric self-collimation device 1 illuminates the reticle 3 on the focus of the collimating objective lens 6, transmits through the beam splitter 4, and after the collimating objective lens 6 converges, passes through the two-dimensional After being reflected by the beam deflection device 17, it is incident on the spectroscopic target detector 11 placed on the measured object, and the spectroscopic target detector 11 divides the incident beam into two beams;

3. After the reflected light beam obtains the two-dimensional small angle change of the spectroscopic target detector 11, it is reflected by the two-dimensional beam deflection device 17 and then converged by the collimating objective lens 6, and is imaged on the CCD image sensor 5 after being reflected by the beam splitter 4, becoming Measuring the signal, the amount of change in the central position of the light spot formed on the CCD image sensor 5 is d ₁ ;

4. The transmitted beam becomes the feedback beam of the angular drift component exactly the same as that of the measuring beam, and is fed back to the drift monitoring device 7. After being focused by the focusing objective lens 9, it is received and monitored by the four-quadrant detector 8 located at the focal plane of the focusing objective lens 9. Angle drift component feedback beam angle drift. When the measurement beam produces an angular drift ε, the angular drift component feedback beam is focused on the focal plane of the focusing objective lens 9 and generates a displacement Δd, thus monitoring the angular drift of the angular drift component feedback beam as:

$\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arctan</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;d</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>$

Where: ε is the angular drift of the angular drift component feedback beam, Δd is the displacement of the focus center of the angular drift component feedback beam from the center of the four-quadrant detector 8, and _f0 is the focal length of the focusing objective lens 9.

5. The computer 12 controls the two-dimensional beam deflecting device 17 in real time according to the angular drift of the angular drift component feedback beam monitored by the drift monitoring device 7. In order to make the two-dimensional beam deflecting device 17 achieve high driving resolution and driving accuracy, Using a two-dimensional beam deflection device 17 composed of a piezoelectric ceramic drive power supply 13, a piezoelectric ceramic displacement device 14, a two-dimensional micro-displacement worktable 15 and a deflection mirror 16, the computer 12 monitors the angular drift according to the drift monitoring device 7 The angular drift of the component feedback beam controls the two-dimensional beam deflection device 17 in real time to adjust the spatial angle of the beam, and the adjustment amount is:

φ＝ε

Where: φ is the adjustment amount of the spatial angle of the beam by the two-dimensional beam deflection device 17, and ε is the angular drift of the angular drift component feedback beam monitored by the drift monitoring device 7;

6. According to step 4 and step 5, the computer 12 adjusts the measurement beam according to the opposite direction of the angular drift, suppresses the angular drift of the measurement beam in real time, and the angular drift of the coupled measurement beam in the measurement signal received by the CCD image sensor 5 also At the same time, it is suppressed. From Fig. 1 and Fig. 2, combined with the principle of geometric optics and optical self-collimation, the variation of the two-dimensional small angle of the spectroscopic target detector 11 can be accurately measured through the measurement signal:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="d"\; filenames="C20051008985200211.png"\; state="\{\{state\}\}">d</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

Here: θ is the variation of the two-dimensional small angle of the spectroscopic target detector 11, _d is the variation of the spot center position formed by the measurement signal on the CCD image sensor 5, and f is the equivalent focal length of the collimating objective lens 6.

It can be seen that after the optical measurement system is improved by using the novel spectroscopic target detector and the closed-loop feedback control technology is introduced, it can be guaranteed that the two-dimensional small angle change can be obtained through the spectroscopic target detector and the angular drift that is exactly the same as the measurement beam characteristics can be separated. The component feedback beam, and the angular drift of the angular drift component feedback beam is monitored by the drift monitoring device. The computer controls the two-dimensional beam deflection device in real time according to the angular drift monitored by the drift monitoring device, so that the measuring beam is in accordance with the angular drift. Adjust in the opposite direction to suppress and eliminate the angular drift of the measurement beam coupled in the measurement signal, which can dynamically compensate the angle measurement error caused by the angular drift of the beam, and solve the problem of angular drift of the beam in long-distance applications. The problem of poor measurement stability and even drifting out of the instrument's field of view increases the measurement distance of the two-dimensional photoelectric autocollimator while improving the measurement stability, so that the measurement scheme realizes long-distance high-precision two-dimensional small angle measurement.

Example 1:

In the two-dimensional photoelectric self-collimation device shown in Figure 1, the spectroscopic target detector 11 is formed by coating half of the inclined working surface of a right-angle prism with a spectroscopic film, and the measuring beam is incident on the working surface coated with the spectroscopic film, and the drift is monitored. The device 7 is composed of a deflection mirror 10 , a focusing objective lens 9 and a four-quadrant detector 8 . First, the drift monitoring device 7 is adjusted to ensure that the center of the photosensitive surface of the four-quadrant detector 8 is located at the focal point of the focusing objective lens 9. After the adjustment, the drift monitoring device 7 should be fixedly connected with the two-dimensional photoelectric self-collimating light pipe 1, Then the two-dimensional photoelectric self-collimation device 1 is calibrated, and after the calibration is completed, the drift monitoring device 7 is no longer adjusted during use;

When measuring, the laser beam emitted by the laser light source 2 of the two-dimensional photoelectric self-collimating light pipe 1 illuminates the reticle 3 on the focal point of the collimating objective lens 6, transmits through the beam splitter 4, and after the collimating objective lens 6 converges, After being reflected by the two-dimensional beam deflection device 17 composed of piezoelectric ceramic drive power supply 13, piezoelectric ceramic displacement device 14, two-dimensional micro-displacement table 15 and deflection mirror 16, it is incident on the spectroscopic target placed on the measured object. Detector 11, the spectroscopic target detector 11 divides the incident beam into two beams: after the reflected beam obtains the two-dimensional small angle change of the spectroscopic target detector 11, it is reflected by the two-dimensional beam deflection device 17 and converged by the collimating objective lens 6 , after being reflected by the beam splitter 4, it is imaged on the CCD image sensor 5 and becomes a measurement signal; the transmitted beam becomes a feedback beam of an angular drift component that is exactly the same as the measurement beam characteristic, and is fed back to the drift monitoring device 7, and is focused by the focusing objective lens 9. The four-quadrant detector 8 located at the focal plane of the focusing objective lens 9 receives and monitors the angle drift of the angle drift component feedback beam. When the measurement beam produces an angular drift ε, the angular drift component feedback beam is focused on the focal plane of the focusing objective lens 9 and generates a displacement Δd, thus monitoring the angular drift of the angular drift component feedback beam is:

$\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arctan</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;d</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>$

Where: ε is the angular drift of the angular drift component feedback beam, Δd is the displacement of the focus center of the angular drift component feedback beam from the center of the four-quadrant detector 8, and _f0 is the focal length of the focusing objective lens 9. The computer 12 feeds back and controls the two-dimensional beam deflection device 17 in real time according to the angular drift component of the angular drift component feedback beam monitored by the drift monitoring device 7, and adjusts the spatial angle of the beam. The adjustment amount is:

φ＝ε

Wherein: φ is the adjustment amount of the spatial angle of the beam by the two-dimensional beam deflection device 17, and ε is the angular drift of the angular drift component feedback beam monitored by the drift monitoring device 7; the computer 12 is opposite to the measuring beam according to the angular drift Direction adjustment, real-time suppression and elimination of the angular drift of the measurement beam coupled in the measurement signal, as shown in Figure 1 and Figure 2, combined with the principle of geometric optics and optical self-collimation, the spectroscopic target detection can be accurately measured through the measurement signal The amount of change of the two-dimensional small angle of device 11:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="d"\; filenames="C20051008985200211.png"\; state="\{\{state\}\}">d</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

Here: θ is the variation of the two-dimensional small angle of the spectroscopic target detector 11, _d is the variation of the spot center position formed by the measurement signal on the CCD image sensor 5, and f is the equivalent focal length of the collimating objective lens 6.

In the present embodiment, the spectroscopic target detector 11 is formed by coating half of the surface of the inclined working surface of a rectangular prism with side length a=b=c=85mm, and the measuring beam is incident on the working surface coated with the spectroscopic coating, and the plated The splitting ratio of the spectroscopic film is: T/R=50/50@632.8nm, the drift amount monitoring device 7 is composed of a deflecting mirror 10, a focusing objective lens 9 and a four-quadrant detector 8 fixedly connected, and the four-quadrant detector 8 is located at the focusing at the focal plane of the objective lens 9. The deflection mirror 10 is made of a plane mirror coated with a high-reflection film. The diameter of the plane mirror 10 is Φ50mm, and the reflectivity coefficient of the high-reflection film: R≥99%@632.8nm; the focal length of the focusing objective lens 9 is f=150mm, and the aperture is D = 50mm; the four-quadrant detector 8 is a S1557 four-quadrant detector from Hamamatsu Corporation of Japan, and the area of the single-quadrant photosensitive surface is 0.2mm ² . The two-dimensional beam deflection device 17 is composed of a piezoelectric ceramic drive power supply 13, a piezoelectric ceramic displacement device 14, a two-dimensional micro-displacement worktable 15 and a deflection mirror 16. The main technical parameters of the piezoelectric ceramic drive power supply 13 are: input voltage range The output voltage range is ±6V, the output voltage range is ±600V, and the minimum resolution of the output voltage is 0.226V. The nonlinear error is less than 0.8%, and the stability error is less than 0.01%. The ceramic driver, the expansion and contraction range is: -6μm～+6μm; the two-dimensional micro-displacement worktable 15 adopts a two-dimensional flexible hinge worktable without mechanical transmission mechanism; the deflection mirror 16 is a plane mirror coated with a high reflection film 10 The diameter is Φ50mm, the reflectivity coefficient of the high-reflection film: R≥99%@632.8nm, the corner resolution of the two-dimensional beam deflection device 17 is better than 0.002", and the corner range is greater than 10", and the steps of monitoring and adjustment are repeated, namely The angular drift of the measurement beam can be suppressed within 0.01″ in real time. The experimental results show that the measurement stability of the two-dimensional photoelectric self-collimation device is better than 0.05 when the measurement resolution reaches 0.01″ and the measurement distance is 20m. ″/h, the measurement uncertainty is better than 0.05″, realizing long-distance high-precision two-dimensional small-angle measurement.

Example 2:

Two-dimensional photoelectric self-collimation device as shown in Figure 1, here, as shown in Figure 5, drift amount monitoring device 7 is made up of focusing objective lens 9 and four-quadrant detector 8, and four-quadrant detector 8 is positioned at the focal point of focusing objective lens 9 On the plane, the spectroscopic target detector 11 is formed by coating half of the inclined working surface of a rectangular prism with a spectroscopic film, and the measuring beam is incident on the working surface coated with the spectroscopic film. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Example 3:

In the two-dimensional photoelectric self-collimation device shown in FIG. 1 , the drift monitoring device 7 is composed of a deflection mirror 10 , a focusing objective lens 9 and a four-quadrant detector 8 . The four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 . As shown in Figure 6(a), the spectroscopic target detector 11 is formed by coating half of the inclined working surface of the corner cube prism 18 with a spectroscopic film, and the measuring beam is incident on the half of the working surface coated with the spectroscopic film. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Example 4:

The two-dimensional photoelectric self-collimation device shown in Figure 1, as shown in Figure 5, the drift monitoring device 7 is made up of a focusing objective lens 9 and a four-quadrant detector 8, and the four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 . As shown in Figure 6(a), the spectroscopic target detector 11 is formed by coating half of the inclined working surface of the corner cube prism 18 with a spectroscopic film, and the measuring beam is incident on the half of the working surface coated with the spectroscopic film. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Example 5:

In the two-dimensional photoelectric self-collimation device shown in FIG. 1 , the drift monitoring device 7 is composed of a deflection mirror 10 , a focusing objective lens 9 and a four-quadrant detector 8 . The four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 . As shown in Figure 6 (b), the spectroscopic target detector 11 is composed of two oppositely placed pentagonal prisms 19 and 20, wherein the working surface of one of the pentagonal prisms 20 is coated with a spectroscopic film, and the measuring beam is formed by the pentagonal prism coated with a spectroscopic film. incident on the work surface. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Embodiment 6:

The two-dimensional photoelectric self-collimation device shown in Figure 1, as shown in Figure 5, the drift monitoring device 7 is made up of a focusing objective lens 9 and a four-quadrant detector 8, and the four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 . As shown in Figure 6 (b), the spectroscopic target detector 11 is composed of two oppositely placed pentagonal prisms 19 and 20, wherein the working surface of one of the pentagonal prisms 20 is coated with a spectroscopic film, and the measuring beam is formed by the pentagonal prism coated with a spectroscopic film. incident on the work surface. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Embodiment 7:

In the two-dimensional photoelectric self-collimation device shown in FIG. 1 , the drift monitoring device 7 is composed of a deflection mirror 10 , a focusing objective lens 9 and a four-quadrant detector 8 . The four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 . As shown in Figure 6 (c), the spectroscopic target detector 11 is composed of two right-angle prisms 21 and 22 placed oppositely, wherein a vertical working surface of a right-angle prism 22 is coated with a spectroscopic film, and the measuring beam is formed by the right angle of the coated spectroscopic film. The prism 22 is incident perpendicular to the working surface. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Embodiment 8:

The two-dimensional photoelectric self-collimation device shown in Figure 1, as shown in Figure 5, the drift monitoring device 7 is made up of a focusing objective lens 9 and a four-quadrant detector 8, and the four-quadrant detector 8 is located at the focal plane of the focusing objective lens 9 . As shown in Figure 6 (c), the spectroscopic target detector 11 is composed of two right-angle prisms 21 and 22 placed oppositely, wherein a vertical working surface of a right-angle prism 22 is coated with a spectroscopic film, and the measuring beam is formed by the right angle of the coated spectroscopic film. The prism 22 is incident perpendicular to the working surface. Other components and working principles of this embodiment are the same as those of Embodiment 1.

Embodiments 2-8 have the same experimental results as Embodiment 1, that is, when the measurement resolution reaches 0.01 " and the measurement distance is 20m, the measurement stability is better than 0.05 "/h, and the measurement uncertainty is better than 0.05 " , to achieve long-distance high-precision two-dimensional small-angle measurement.

The specific implementation of the present invention and test effect have been described above in conjunction with accompanying drawing, but these explanations can not be interpreted as limiting the scope of the present invention, and the scope of protection of the present invention is defined by the appended claims, and any right in the present invention Modifications made on the basis of requirements are within the protection scope of the present invention.

Claims (7)

1. A long-distance two-dimensional photoelectric self-collimation device for drift target feedback control, comprising a two-dimensional photoelectric self-collimation light tube, a computer, a two-dimensional beam deflection device, and a drift monitoring device, said two-dimensional photoelectric The self-collimating light pipe is composed of a laser light source, a reticle, a beam splitter, a CCD image sensor, and a collimating objective lens placed in sequence. The drift monitoring device includes a focusing objective lens and a four-quadrant detector fixedly connected together. Said two-dimensional beam deflection device is composed of a piezoelectric ceramic drive power supply, a piezoelectric ceramic displacement device, a two-dimensional micro-displacement worktable and a deflection mirror, and is characterized in that it also includes a spectroscopic target detector, which is located at Between the two-dimensional beam deflection device and the drift amount monitoring device, the spectroscopic target detector separates and feeds back the angular drift component feedback beam with exactly the same characteristics as the measurement beam while acquiring its own two-dimensional small angle variation measurement signal, The drift monitoring device monitors the angular drift of the angular drift component feedback beam in real time, and the computer controls the two-dimensional beam deflection device in real time according to the angular drift monitored by the drift monitoring device, and adjusts the measuring beam in the direction opposite to the angular drift , to suppress the angular drift of the measurement beam coupled into the measurement signal. 2. The device according to claim 1, characterized in that said spectroscopic target detector is formed by coating half of the inclined working surface of a rectangular prism with a spectroscopic film, and the measuring beam is incident on the working surface coated with a spectroscopic film. 3. The device according to claim 1, characterized in that said spectroscopic target detector is formed by coating a spectroscopic film on half of the inclined working surface of a corner cube, and the measuring beam is incident on the working surface coated with a spectroscopic film. 4. The device according to claim 1, characterized in that said spectroscopic target detector is made of two oppositely placed pentagonal prisms, wherein the working surface of one of the pentagonal prisms is coated with a spectroscopic film, and the measuring beam is formed by coating the spectroscopic film. The working surface of the penta prism is incident. 5. The device according to claim 1, wherein said spectroscopic target detector is composed of two right-angle prisms placed oppositely, wherein a vertical working surface of a right-angle prism is coated with a spectroscopic film, and the measuring beam is coated with a spectroscopic film. The membrane is incident on the normal working surface of the rectangular prism. 6. The device according to any one of claims 1-5, characterized in that said drift monitoring device is composed of a deflection mirror, a focusing objective lens and a four-quadrant detector fixedly connected, and the four-quadrant detector is located at the focusing the focal plane of the objective lens. 7. A long-distance two-dimensional photoelectric self-collimation method of drift target feedback control, characterized in that said method comprises the following steps: (1). The two-dimensional photoelectric self-collimating light tube emits a measuring beam; (2). The spectroscopic target detector receives the measuring beam and separates it into a reflected beam and a transmitted beam; (3). The reflected light beam acquires the two-dimensional small-angle variation of the spectroscopic target detector and is received by the CCD image sensor to become a measurement signal; (4). The transmitted beam separates the angular drift component feedback beam with the same characteristics as the measurement beam, and feeds it back to the drift monitoring device. After the focusing objective lens is received by the four-quadrant detector, the angular drift of the angular drift component feedback beam is monitored: $\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arctan</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;d</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>$ Wherein: ε is the angular drift of the angular drift component feedback beam, Δd is the displacement of the focus center of the angular drift component feedback beam from the center of the four-quadrant detector, and f ₀ is the focal length of the focusing objective lens; (5). The computer controls the two-dimensional beam deflection device in real time according to the angular drift of the angular drift component feedback beam monitored by the drift monitoring device, so that the measuring beam is adjusted in the opposite direction of the angular drift. The adjustment amount is: φ＝ε Where: φ is the adjustment amount of the two-dimensional beam deflection device to the spatial angle of the beam, and ε is the angular drift of the angular drift component feedback beam; (6). Repeatedly adjust according to step 3 and step 4, suppress and eliminate the angular drift of the measuring beam coupled in the measuring signal in real time, and accurately measure the variation of the two-dimensional small angle of the spectroscopic target detector by the measuring signal: $\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$ Here: θ is the variation of the two-dimensional small angle of the spectroscopic target detector, d ₁ is the variation of the spot center position formed by the measurement signal on the CCD image sensor, and f is the equivalent focal length of the collimating objective lens.

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