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Research Of Optimization Performance And High Accuracy Measurement Technology For Single Frequency Laser Interferometer

Posted on:2014-04-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:L HuangFull Text:PDF
GTID:1268330425993041Subject:Optical Engineering
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With the advancement of science and technology, laser interferometer measurement technology has been widely applied in various fields. On the one hand, because the microelectronics, micro-mechanical, micro-optics and modern ultra-precision machinery processing industry bring forward increasingly high measurement accuracy requirements. At the same time, they require a greater measurement range. But the other methods are difficult to competent. This requirements of large measurement range and high precision measurement accuracy can be achieved by laser interferometer only. Moreover, modern laser interferometer measurement technology has the advantage of high sensitivity, large measurement range and adapting the harsh environment. Simultaneously, the "meter" is defined by optical wave directly which is easily traced to the source, so it has been widely range of applications in modern industrial.Currently, the research of laser interferometer measurement technology is mainly focused on two aspects:One aspect is the research of small range, high precision measurement and nanometer resolution in the metrology laboratory environment. On the other aspect, the research focus to be better anti-jamming performance, better reliability, higher degree of automation and measurement speed. The above content is mainly attributed to three aspects:(l)The frequency stabilization method of stronger anti-interference performance;(2)Background noise processing technology and signal processing techniques etc.(3)The method of reducing or compensating nonlinearity error, lower the structure requirements of the light path and compensating the influence of index of refraction etc.Improve existence drawbacks of the single frequency laser interferometer, enhance its anti-jamming capability, optimize the nonlinear error, not only make it develop into the field of nano-metrology, and this research can also make it go out the lab, expand its scope of application. It is adaptted them to modern industrial production requirements for low-cost, high accuracy. So, the study of single frequency laser interferometer system has a very important theoretical value and practical significance.This issue mainly study the principle, structure, data processing method and its optimization adjustment for single frequency laser interferometer system.We develop laser measuring machine of adjustable optical path, and apply the research of laser interferometer to measure length of gauge blocks.(1)There are some defects of anti-jamming capability and poor stability for traditional two channels signal single frequency laser interferometer system. Four channels signal system is advanced by this article. The system has more simpler structure and smaller nonlinearity error than dual frequency laser interferometer system. By designing the light path and adopting polarizing beam splitter(PBS), there are no reflected light return to laser source. So the system has the function of opto-isolated. At the same time, four channels signal system has favorable symmetry capability. The source of common-mode noise has been controlled. The capability of anti-jamming and stability is improved.(2)Pretreatment of four channels signal system is advanced for single frequency laser interferometer system. The main features include:photoelectric conversion system, anti-jamming self-adaptation system, analog-to-digital conversion part, least squares algorithm of nonlinearity error etc. The article mainly researched the anti-jamming self-adaptation system and least squares algorithm for ellipse fitting, and the simulation experiment is made.(3)The optimization adjustment method to improve single-frequency laser interferometer is advanced. The method to adjust light path is summarized. Optical elements are adjusted to enhance the system performance. Consequently, the structure and stability are optimized by decrease the nonlinearity, and the accuracy is advanced also.(4)Noise mathematical model for the system is founded. The experimental results show that, the noise of the signal can be disposed by this anti-jamming self-adaptation system. Accordingly, high-precision tracking to the direct current component is achieved.Laser interferometer has been applied to the field of measurement for several years, scholars from various countries have devoted a lot of time and effort to its development,and the system has been rapid development. Along with laser interferometer theory is enriched and developed, types of interferometer continue to appear. Each kind of laser interferometer has its own applications. The article has research the development process and its scope of application of the laser interferometer. Four channels signal system is adopted by the study inventively. At the same time, pretreatment of four channels signal system, anti-jamming self-adaptation system and optimization adjustment method are adopted to improve the performance of the system. So that single frequency laser interferometer system can be applied in a broader range. The experimental results show that, the noise of the signal can be disposed by this system, system signal-to-noise achieve to75dBo The accuracy of laser measuring machine which installed by single frequency laser interferometer system achieves to±(0.3μm+1.5×10-6L), and the measurement reproducibility is0.2μm.
Keywords/Search Tags:single frequency laser interferometer, direct current drift nonlinearityerror, pretreatment of four channels signal system, least squares algorithm forellipse fitting, anti-jamming self-adaptation system, optimization adjustment, lasermeasuring machine
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