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内径测量微型精密光学测头及其信号处理研究
Research on Precision Optical Mini-head of Inradius Measuring and Signal Processing
【作者】 林力;
【导师】 邾继贵;
【作者基本信息】 天津大学 , 测试计量技术及仪器, 2010, 硕士
【摘要】 随着汽车工业的发展,现有的汽车发动机箱体轴孔内径测量技术难以满足日益增长的测量要求。在现代测量中,光电检测技术由于其优越性得到了广泛的应用。本文分析了国内外的光电微位移检测技术发作状况,自行设计了微型精密光学测头,采用光电检测技术实现对小型轴孔的内径测量。本文根据测量要求设计了一个机械测棒,机械测棒均布四个单独的光学测头,相邻两个测头位置相互垂直,相对两个测头位置在同一直线上。四个单独测头分别测单个径向位移,相对的两个测头就测得直径,四个测头可测得两组直径数据,多次测量后,作平均处理。单独测头应用激光三角法原理,使用PSD作为位移传感器,测量时,安装在测头上的光纤准直器准直发射出一束激光,激光打到被测物表面上发生漫发射,安装在测头上的接收物镜会聚部分漫反射光并将这部分光传至PSD感光面,PSD根据入射光重心位置产生两路电流信号,通过测量这两路电流信号就可以通过计算得到被测物的位移量。本文研究的具体内容有:1.分析了国内外光电检测技术的发展状况,阐述了本文采用的测量原理即激光三角法的原理及应用该原理测量时遵循Scheimpflug条件的必要性。2.比较光学位移传感器CCD和PSD的优缺点,选择PSD作为本文的光学位移传感器,研究了PSD传感器的使用特性,及这些特性对整个测头测量系统的影响,根据PSD特性选择光源。3.根据测量要求,对测头的机械结构和光学结构进行了设计,设计的机械结构紧凑、精密,有着严格的几何要求和尺寸配合关系。4.根据测头机械结构进行传感器的处理电路板的设计,设计信号处理电路,实现传感器信号的提取、I/V转换、放大、A/D转换、存储、传输等功能。5.设计标定实验方法,标定单独测头和测棒;进行总体误差分析,提出减小误差方法。
【Abstract】 With the car industry development, the existing technology used in measuring car engine box bores hole could not meet the growing measure requirement. In modern measurement system, photoelectric detection technology is widely used for its superiority. However, owing to the structural dimension construction, this method could not be used in small space. This article analyzed the photoelectric micrometric displacement detection technology and self-designed mini measuring head to realize mini-hole size measurement.According to the measurement requirement, this paper designs a mechanical bar with four separated head uniform distributed on it. Every two interfacing heads are orthogonal and every two opposite heads are co-liner. Each head detects one radial 7displacement, so that two heads can get a diameter and four heads can get two groups of data. Then, get average value by multiple detections. A single detection head take laser triangulation as principle and PSD as displacement sensor. When detecting, a laser sent by fiber-optical collimation fixed in the head takes place diffuse reflection when it get to the object surface. The mirror fixed in the head will collect a part of the diffuse reflection laser and send it to PSD. PSD will generate two electric currents according to the focus position of incident light. So we can get the displacement by calculating the value of the two electric currents.The main content of this article includes:1.Analyze the development situation of photoelectric detection in home and outdoor, elaborate triangulation principle and the necessary of following the condition of Scheimpflug when applying this principle.2.Compare optical displacement sensor PSD and CCD merits and drawbacks, choose PSD as the optical displacement sensor in this article. Research the application characteristic of PSD sensor and the affection caused by the whole detection system. Choose light source according to PSD characteristic.3.Design the mechanical and optical structure according to the detection requirement to make the structure compact and precise and possess strict geometry demand and dimensional coordination relationship.4.Design the sensor circuit board according to the mechanical structure to deal with signals and realize functions such as signal extract, I/V conversion, magnification, A/D conversion, storage and transmission. 5.Design calibration experiments to calibrate solo detection head and bar. Analyze the detection mistake in whole and advance a way to diminish it.
【Key words】 mini detection head; triangulation; PSD; operational amplifier; weak signal;