| Self-mixing Interference (SMI) technology rises and develops rapidly in therecent decades, it is a kind of precision measurement technology. The system issimple, compact, low cost, precision, and most is non-contact measurement whichcan avoid the wear and tear to the measured surface, so it has been widely used in themeasurement field.This topic based on the theory model of Self-mixing Interference (SMI), usingLabVIEW and MATLAB complex programming, designs a virtual instrument whichcan measure displacement and can simulate the signal of the SMI. The virtualinstrument can simulate the SMI signal, reconstruct the wave of object displacementand complete object displacement measurement. The virtual instrument operatessimply, can show the influence of various parameters on the signals related the systemintuitively, and make the study more easily. And because of its software, the modularstructure, makes the equipment upgrades, improvements and new features added arevery convenient, will not affect the original system, will not result in cost waste. canbe intuitive show the, convenient for scholars to study laser hybrid learning andresearch in the theory of displacement measurement. If added DAQ data acquisitionsystem and related signal processing function this virtual instrument can make actualdisplacement measurement.This paper introduces the design process of virtual instrument in detail. Firstlyintroduces the rise, the development and present situation of the laser SMI technology,then tells the received general mathematical model of SMI system which can bederived by two kinds of way. Based on the mathematical model, simulate the graphic,obtain simulation algorithm of interference signal waveform in displacementmeasurement system under the weak light level and the moderate optical feedback，and then simulates and analyses the influence of system parameters on theinterference signal. Displacement signal reduction algorithm is deduced based on thestudy of the simulated interference signal in SMI displacement measurement system,and then reconstruct the external object displacement waveform figure, complete thedisplacement measurement based on laser SMI signal. By error analysis, the relative indication error of displacement measurement system is obtained which is between0.03%-0.06%, and is small. Finally introduced the platform of virtual instrument,instrument panel design and the hybrid programming of LabVIEW and MATLABusing the MATLAB Script node, and then summarizes the full text, put forward thedirection on the extension function and improvement of the virtual instrument in thelater. |
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