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Signal integrity in capacitive and piezoresistive single- and multi-axis MEMS gyroscopes under vibrations
No full textThe work investigates effects of external mechanical vibrations, with a frequency up to 40. kHz, on the operation of micro-electromechanical gyroscopes of different architecture and sensing technology. The analyzed devices differ (i) in the number of sensing axes (one, two or three) per single drive frame, so in the number of resonant modes within the tested vibration range, and (ii) in the used sense transduction technology (parallel-plate capacitances or piezoresistive nano-gauges). After theoretically modeling effects of vibrations occurring around the frequency of in-plane and out-of-plane resonant modes, in presence of process imperfections and nonlinearities, the work benchmarks the predictions through an extensive experimental campaign: using a shaker, vibrations of controlled amplitude and frequency are applied, in operation, to the devices along both in-plane and out-of-plane axes. Results show that, within the tested sensors, the best tolerance to vibrations, quantitatively measured in terms of angle random walk (ARW) worsening, is achieved for single-axis structures based on piezoresistive sensing. Their ARW degrades in the worst case by 1.2 times, compared to a 230-fold degradation observed in 3-axis capacitive sensors
Capacitive vs piezoresistive MEMS gyroscopes: a theoretical and experimental noise comparison
Full text linkAbstractThis work aims both at theoretically formalizing a comparison between piezoresistive (PZR) and capacitive (CAP) gyroscopes in terms of resolution limits, and at validating the predictions through experimental measurements on MEMS devices of both types. As predicted by the developed theory, PZR gyroscopes, well immune to parasitic capacitances and void of feedback resistance noise, show 10-fold better angle random walk (ARW) than CAP gyroscopes for the same nominal mode-split value, the same drive-motion amplitude and the same electronic noise density
Reliability of gyroscopes based on piezoresistive nano-gauges against shock and free-drop tests
No full textAmplitude motion stabilization in drive resonators limited by an automatic feather cotnact mechanism
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LARGE FULL SCALE, LINEARITY AND CROSS-AXIS REJECTION IN LOW-POWER 3-AXIS GYROSCOPES BASED ON NANOSCALE PIEZORESISTORS
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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