The System Of Laser Triangulation Measuring

With the development of the industrial measurement and the improvement of measuring precision and efficiency, the traditional contact-measurement can’t meet demand. Laser rangefinder triangle method has the advantages of high-speed, non-contact and high precision, which is widely applied to the measurement of distance, angle, and position, and becomes a hot topic in the field of measurement research.After analyzed the common use types of laser triangulation system, the advantages and disadvantages of it, this thesis adopts the direct-type triangulation method. Also we have designed an object micro displacement measuring system, which is based on SCM and CCD.Firstly, we referred to lots of papers, studied the principle of laser triangulation measurement, tested and verified the Scheimpflug constraints of the optical system. Based on the principle of triangulation measuring system, the structure parameters are obtained. To obtain the design requirements, we optimized these parameters by Mathematica5.0. We finally got a set of reliable system parameters and calculated the range and accuracy of our system. To fit the structure parameters, we selected light source, a collimating system, filter and image lens.Secondly, in the drive and signal acquisition unit, we used the microprocessor system in the basis of AVR single-chip, implemented linear CCD drive circuit and wrote the driving program. We completed the CCD output signal amplification and filtering pre-processing circuit, designed binary signal, and also obtained the spot position of measurement. We also wrote the program to control LCD.Finally, we analyzed the system error and proposed several methods to improve the system performance. The innovation of this paper is that we changed the image lens to a zone plate. Considering the subsequent design, we used a zone plate to substitute for collimation and imaging system, which can make the optical path simple and the system cheaper. We calculated the radius relations of the collimating and image zone plates.