关于工作条件下平面激光多普勒测速仪精度的影响因素--本科毕业论文中英文翻译材料（可编辑）.doc

关于工作条件下平面激光多普勒测速仪精度的影响因素--本科毕业论文中英文翻译材料 The Influence of Operating Conditions on The Accuracy of In-plane Laser Doppler Velocimetry Measurements Abstract The use of laser Doppler velocimeters in the analysis of in-plane motion of a solid body is spreading both in the scientific research and in the industrial experimentation fields. The applicability and accuracy of this measurement technique depend on the conditions in which the system operates: the level of the signal available, the characteristics of the surface observed, the environmental conditions, the presence of other shifts in addition to the ones pointed out, etc. This is the subject of this analysis carried out through a comparison between an axial vibrometer in conditions of ideal operation and a tangential vibrometer operating on various surface states. The experimental results have been supported by a theoretic modelling of the interaction between this measuring system and the measurand, thereby providing a rational description of the phenomena observed. This study has made it possible to verify the interfering inputs due to the various operative conditions and the chance of extending the use of the measurement system also to cases in which the applications of the technique proves to be difficult. ó 1999 Elsevier Science Ltd. All rights reserved. 1. Introduction The in-plane vibrometer measures the velocity component perpendicular to its optical axis and therefore it can be suitably utilised to experimentally determine in-plane or tangential vibrations. Its operation is based on the interaction between the surface roughness and the interference fringes area formed in correspondence with the intersection of two laser beams Fig. 1. Typical performances of commercial systems are a bandwidth from 0 to 10 kHz and a velocity range up to 100 m/ s DC. The determination of the velocity value occurs by Doppler effects in the scattered light, which is collected by the optics to the