Modelling of MEMS vibratory gyroscopes utilizing phase detection
Date
2008-03
Authors
Dreyer, Antonie Christoffel
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
This thesis aims to contribute to the modelling and analysis of MEMS gyroscope
technologies. Various gyroscope types are studied, and the phase-based vibratory
gyroscope is then selected for further investigation.
In the literature, vibratory MEMS gyroscopes are mostly used in a single excitation
and amplitude detection mode. However, a dual excitation and phase detection
mode has recently been proposed, since phase-based detection, as opposed
to amplitude-based detection modes, may be expected to increase measurement
accuracy (in turn since improved signal-to-noise ratios may be expected).
However, the presented analytical model was relatively crude, and the
assumptions made appear unrealistic. Accordingly, in this thesis, an improved
analyticalmodel is developed.
To describe the dual excitation and phase detection problem more comprehensively,
principles of classical dynamics are used herein to investigate the dual excitation
of a two degree of freedom spring-mass-damper system subjected to an
applied rotation rate. In doing so, an analytical formulation including mechanical
coupling effects is extended into a generalized form, after which the amplitude
and phase responses of the mechanically uncoupled system are interpreted.
The differences between the amplitude and phase measurement techniques are
illustrated.
Finally, the system is modelled numerically, and the scale factor of a hypothetical
device based on the phase-based detection method is optimized, subject to
constraints on the nonlinearity of the device, using constrained mathematical
optimization techniques.
Description
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008.
Keywords
MEMS, Vibratory gyroscopes, Phase-based, Mathematical modelling, Dissertations -- Mechanical engineering, Theses -- Mechanical engineering, Gyroscopes