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Tesi etd-01122014-165816


Thesis type
Tesi di dottorato di ricerca
Author
GIOMI, EDOARDO
URN
etd-01122014-165816
Title
Inertial MEMS: readout, test and application
Settore scientifico disciplinare
ING-INF/01
Corso di studi
INGEGNERIA
Commissione
tutor Prof. Fanucci, Luca
tutor Prof. Roncella, Roberto
Parole chiave
  • readout
  • mems
  • intertial
  • gyroscope
  • accelerometer
  • sensor
  • test
Data inizio appello
21/02/2014;
Consultabilità
completa
Riassunto analitico
This thesis moves towards the investigation of Micro Electro-Mechanical Systems<br>(MEMS) intertial sensors from different perspectives and points of view: readout,<br>test and application.<br>Chapter 1 deals with the state-of-the-art for the interfaces usually employed for 3-<br>axes micromachined gyroscopes. Several architecture based on multiplexing schemes<br>in order to extremely simplify the analog front-end which can be based on a single<br>charge amplifier are analysed and compared. A novel solution that experiments an<br>innovative readout technique based on a special analog-Code Division Multiplexing<br>Access (CDMA) is presented; this architecture can reach a considerable reduction of<br>the Analog Front-End (AFE) with reference to other multiplexing schemes. Many<br>family codes have been considered in order to find the best trade-off between<br>performance and complexity. System-level simulations prove the effectiveness of<br>this technique in processing all the required signals. A case study is also analysed: a<br>comparison with the SD740 micro-machined integrated inertial module with tri-axial<br>gyroscope by SensorDynamics AG is provided.<br>MEMS accelerometers are widely used in the automotive and aeronautics fields<br>and are becoming extremely popular in a wide range of consumer electronics<br>products. The cost of testing is a major one within the manufacturing process,<br>because MEMS accelerometer characterization requires a series of tests that include<br>physical stimuli. The calibration and the functional testing are the most challenging<br>and a wide selection of Automatic Test Equipments (ATEs) is available on the<br>market for this purpose; those equipments provide a full characterization of the<br>Device Under Test (DUT), from low-g to high-g levels, even over temperature.<br>Chapter 2 presents a novel solution that experiments an innovative procedure to<br>perform a characterization at medium-g levels. The presented approach can be<br>applied to low-cost ATEs obtaining challenging results. The procedure is deeply investigated and an experimental setup is described. A case study is also analysed:<br>some already trimmed Three Degrees of Freedom (3DoF)-Inertial Measurement<br>Unit (IMU) modules (three-axes accelerometer integrated with a mixed signal ASIC),<br>from SensorDynamics AG are tested with the experimental setup and analysed, for<br>the first time, at medium-g levels.<br>Standard preprocessing techniques for removing the ground response from vehicle-<br>mounted Ground Penetrating Radar (GPR) data may fail when used on rough<br>terrain. In Chapter 3, a Laser Imaging Detection and Ranging (LIDAR) system<br>and a Global Positioning System (GPS)/IMU is integrated into a prototype system<br>with the GPR and provided high-resolution measurements of the ground surface.<br>Two modifications to preprocessing were proposed for mitigating the ground bounce<br>based on the available LIDAR data. An experiment is carried out on a set of<br>GPR/LIDAR data collected with the integrated prototype vehicle over lanes with<br>artificially rough terrain, consisting of targets buried under or near mounds, ruts<br>and potholes. A stabilization technique for multi-element vehicle-mounted GPR is<br>also presented.
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