Design Of Solid Laser Doppler Velocimetry

Laser Doppler velocimetry is one of the most important ways of measuring thevelocity of the moving object. Doppler velocimetry,with its high measurementprecision, wide speed range, high spatial resolution, fast dynamic response, non-contactmeasurement, etc. are rapidly developing to become extremely important speedmeasuring device in many areas. Therefore it is of great significance for the study of thevelocimetry.Firstly the paper introduces the historical development of,laser Dopplervelocimetry and its domestic and foreign applications. And then the paper expoundedthe basic principles and the optical path mode of laser Doppler velocimetry.Based on theprinciple of Doppler velocimetry and comparison of several optical path modeS andcomponents analysis, selection and parameter setting, we designed a dual beam-doublescattering optical structure, the light collection device, pre-amplifier and filtercircuit.The paper then introduces several important methods of the Doppler signalprocessing,and adopted Fast Fourier Transform (FFT) after comparative analysis.Based on this method,a DSP digital signal processing module was designed, whichincluded a central processor, A/D analog-to-digital converter and the FIR filter. Dataacquisition and processing module of the central processor design is based on the TexasInstruments TMS320C6713and MAX1420chip,which is of real-time and fast signalprocessing.Finally, a Doppler velocimetry LDV apparatus was built in the laboratory tomeasure the velocity of the moving solid turntable. By this means, successfulmeasurement of the speed of the solid turntable was obtained,which is of a certaindegree of accuracy. So it achieved the purpose of measuring the speed of the movingsolid and verified the feasibility of the entire speed measuring design.