A precision laser scanning system for experimental modal analysis: its test and calibration

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dc.contributor.authorLi, Xinzuo Williamen
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T21:43:25Zen
dc.date.adate2009-08-22en
dc.date.available2014-03-14T21:43:25Zen
dc.date.issued1992-10-05en
dc.date.rdate2009-08-22en
dc.date.sdate2009-08-22en
dc.description.abstractThe Laser Doppler Velocimetry technique has been widely used for dynamic measurements and experimental modal analysis. A laser scanning system that provides position accuracy, speed, and flexibility plays a key role in this technique. This thesis gives an overview of various laser scanning techniques and the requirements of a laser scanning system for the LDV and modal testing. The G3B/DE2488, a most-advanced galvanometer-based laser scanning system manufactured by the General Scanning Inc., is one of the most suitable laser scanning systems for the LDV and modal testing. The focus of this work was to test and calibrate such a scanning system to meet the requirements for modal testing. A new method to determine laser scanning angles was introduced. Based on this test method, a laser scanning system test rig was designed and constructed. To determine a laser bealTI scanning angle, the laser and scanner together were translated in a direction perpendicular to the target plane by using a micrometerdriven translation stage. The translation of the scanned laser spot at the target plane due to the translation of the laser-scanner unit was traced by a photodetector and another set of micrometer-driven translation stages that moved in the target plane. The laser beam scanning angle was calculated from the traveled distances of the laser-scanner unit and of the laser spot at the target plane. The test setup was used to determine the overall performance of the G3B/DE2488 which included the scanning time and accuracy. The errors that affected the scanning accuracy were analyzed. Due to the relatively low precision and quality of the cost-constrained equipment used in the test setup, the accuracy of determining a scanning angle was not very high (around 50 µrad). However, if some high-accuracy and high-resolution equipment such as a beam profiler and a set of motor-driven stages are used, this test method has the potential to determine a laser beam scanning angle with an accuracy in the order of microradians.en
dc.description.degreeMaster of Scienceen
dc.format.extentxi, 156 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-08222009-040335en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08222009-040335/en
dc.identifier.urihttp://hdl.handle.net/10919/44385en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1992.L52.pdfen
dc.relation.isformatofOCLC# 27701567en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1992.L52en
dc.subject.lcshLaser Doppler velocimeteren
dc.subject.lcshModal analysisen
dc.titleA precision laser scanning system for experimental modal analysis: its test and calibrationen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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