【作者】 刘江；

【导师】 汪涛；

【作者基本信息】 重庆大学 ， 光学工程， 2014， 硕士

【摘要】 激光三角测量技术具有测量精度高、速度快、适用范围广和结构简单等特点，能满足现代工业生产、加工现场对测量技术高精度、非接触实时在线测量的要求。国外在激光三角测量技术领域发展起步较早，以欧洲、美国和日本为主要代表。近年来市场上不断地涌现出欧美日生产的激光三角距离（厚度）传感器，这些产品都表现出精度高、抗干扰能力强且适用于特殊领域运用等的优越性能，但是都很昂贵。国内的激光三角测量技术发展起步较晚，直到今天都还处于实验运用阶段，不少著名高校、研究机构对激光三角距离（厚度）传感器进行了深入研究且取得了一定成果，但目前市场上性能优越的国产激光三角距离（厚度）传感器很少，零星出现的产品都普遍存在结构复杂、不易安装和无法满足恶劣环境下稳定测量的缺陷。如何设计出精度高、稳定性好、结构简单易安装且能适用于恶劣环境的激光三角距离（厚度）传感器，是目前国内激光三角测量技术领域亟待解决的难题。本文设计了一套基于FPGA（Field Programmable Gate Array）的PSD双光路直射式激光三角厚度在线测量仪，具有精度高、响应速度快、结构紧凑、稳定性好等特点，主要完成的工作如下：1.研究激光三角法厚度测量的理论基础。PSD的工作原理、激光三角测距原理（直射式、斜射式及其比较）、激光三角测厚原理。2.确定系统的厚度测量方案，进行底层硬件模块的划分。运用双光路激光三角测距系统，采用标定测量法。系统硬件包括：光学系统、步进电机及其驱动电路、PSD运放电路、转接电路和PSD信号数据采集电路。3.设计系统硬件电路。PSD驱动及运放电路，主要实现PSD微弱电流信号的I/V转换和后级放大；转接电路，完成PSD运放信号的转接；PSD信号数据采集电路，主要完成PSD运放信号的AD转化、存储、处理和厚度值的实时显示。4.设计系统软件。在Quartus-II开发环境下完成系统四大功能模块的Verilog HDL程序编写和调试，分别为初始值测定模块、实时标定模块、实际测量模块和厚度实时显示模块。5.在系统软、硬件平台下完成厚度值的实时在线测量。完成单点单次采样法、单点多次采样平均法下的厚度测量并对两种方法下的测量结果进行分析和比较。6.研究系统测量的误差来源和改进措施。对光学系统、被测物表面性质、PSD自身线性度、PSD运放电路、AD转换器和环境因素等误差来源进行分析，并提出相应的改进措施。更多还原

【Abstract】 Laser triangulation measurement technology has the features of high accuracy,fastspeed,wide application and simpe structure,can meet the requirements of measurementtechnology of high precision,non-contact real-time online measurement in theproducing and processing sites of modern industry.The development of laser triangulation measurement technology field started earlyin foreign countries,in which there are some main representatives as Europe,USA andJapan.In recent years,the market has emerged many products of laser triangulationdistance(thickness) sensor made in Europe,USA and Japan,these products have shownsome superior performances of high precision,strong anti-interference ability and issuitable for the special field of application,but they are very expensive.The developmentof laser triangulation measurement technology started late at home,until today is still inthe experimental and application stage,many famous universities and researchinstitutions made thorough research about laser triangulation distance(thickness) sensorsand achived some certain results,but currently the laser triangulation distance(thickness)sensor made in our country with superior performances on the market is rare,these fewproducts generally have the defect of complex structure,difficult installation and can notmeet the requirements of stable measurement under harsh environment.Currently,in the field of domestic laser triangulation measurement technology,it isthe urgent and difficult problem to design a laser triangulation distance(thickness)sensor with high accuracy,good stability,simple structure,easy installation and can beapplied under harsh environment.This paper designs a direct online laser triangulationthickness measuring instrument of double optical path of PSD,which is based onFPGA(Field programming Gate Array) and has the features of high accuracy,fastresponse speed,compact structure,good stability and so on,the main work is as follows:1. To research the theoretical basis of laser triangulation thickness measurement.The working principle of PSD,the principle of laser triangulation distancemeasurement(direct,oblique and comparision),the principle of laser triangulationthickness measurement.2. To make the thickness measurement plan of system,to devide the underlayinghardware modules.To apply the laser triangulation distance measuring system of double optical path,to use the method of calibration measurement,the system’s hardware includes:theoptical system,stepping motor and its driving circuit,PSD op amp circuit,swichingcircuit and the data acquisition circuit of PSD signal.3. To design the hardware of system.The driving and operational amplifier circuit of PSD,mainly to achieve the I/Vconversion of weak current signal and the post amplification of PSD;the swichingcircuit,to complete the PSD op amp signal transfer;the data acquisition circuit of PSDsignal,mainly to complete the AD conversion,storage,processing of PSD op amp signaland the real time display of thickness values.4. To design the software of system.To complete the Verilog HDL programming and debugging of system’s four majormodule in Quartus-II development environment,respectively,for the initial valuemeasurement module,real time calibration module,real measurement module andthickness’s real time display module.5. To finish the thickness’s real-time online measurement on the platform ofsystem’s software and hardware.To complete the thickness’s measurement by singlepoint single sampling and simple point multi smpling average methods,and to make theanalization and comparision of measurement results of two methods.6. To research the error sources and improvement measures of system’s thicknessmeasurement.To analize the error sources from optical system,properties of measuredsurface,linearity of PSD,PSD op amp circuit,AD converter,environment factor and soon,and to put forward the corresponding improvement measures.更多还原