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dc.contributor.authorSchmittdiel, Michael C.en_US
dc.date.accessioned2005-09-16T15:20:00Z
dc.date.available2005-09-16T15:20:00Z
dc.date.issued2004-07-14en_US
dc.identifier.urihttp://hdl.handle.net/1853/7261
dc.description.abstractThis thesis describes the creation of a metrology system based upon an actively controlled diffraction grating interferometer, which measures relative linear distances. The dynamics of this sensor are estimated based on experimental testing, and a suitable controller is designed to maintain the position of the sensor in the most sensitive operating region. This controller is implemented on a field programmable gate array (FPGA) processor, which allows for flexible programming and real-time control. The sample under test is mounted atop a three axis linear stage system, which allows the diffraction grating interferometer to scan across the surface of the device, creating maps of the static and dynamic measurements. The controller is shown to maintain the sensitivity of the sensor during this operation. This insures all data are taken on the same scale, creating more accurate results. The controller increases the signal to noise ratio as compared to the system without the controller. The specifications of the entire metrology system are detailed including the sensor and controller bandwidth, the vertical and horizontal resolution, and the signal to noise ratio. A case study utilizing a capacitive micromachined ultrasonic transducer (cMUT) is presented. The sensor generates static and dynamic displacement maps of the surface of this MEMS device. The controller improves these measurements by maintaining a position of high sensitivity during operation. Finally, the preliminary results of a miniaturized version of this system are presented including the implementation of two fully independent parallel sensors. This allows for array implementation of these sensors, which is crucial for the batch fabrication photolithography techniques used to create many MEMS devices. Recommendations on the future work needed to complete the array implementation are given in conjunction with methods for increasing the resolution and robustness of the macroscale system described in this thesis.en_US
dc.format.extent8780715 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectMetrologyen_US
dc.subjectMEMS
dc.subjectInterferometers
dc.subjectMicroscale
dc.subjectDiffraction gratings
dc.subjectActive control
dc.subjectHarmonic locking
dc.subject.lcshMetrologyen_US
dc.subject.lcshMicrostructureen_US
dc.subject.lcshDetectorsen_US
dc.subject.lcshDiffraction gratingsen_US
dc.subject.lcshInterferometersen_US
dc.titleActive control of a diffraction grating interferometer for microscale devicesen_US
dc.typeThesisen_US
dc.description.degreeM.S.en_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.advisorCommittee Chair: Dr. Thomas R. Kurfess; Committee Member: Dr. F. Levent Degertekin; Committee Member: Dr. William P. Kingen_US


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