Modelling of MEMS vibratory gyroscopes utilizing phase detection

[摘要] This thesis aims to contribute to the modelling and analysis of MEMS gyroscopetechnologies. Various gyroscope types are studied, and the phase-based vibratorygyroscope is then selected for further investigation.In the literature, vibratory MEMS gyroscopes are mostly used in a single excitationand amplitude detection mode. However, a dual excitation and phase detectionmode has recently been proposed, since phase-based detection, as opposedto amplitude-based detection modes, may be expected to increase measurementaccuracy (in turn since improved signal-to-noise ratios may be expected).However, the presented analytical model was relatively crude, and theassumptions made appear unrealistic. Accordingly, in this thesis, an improvedanalyticalmodel is developed.To describe the dual excitation and phase detection problem more comprehensively,principles of classical dynamics are used herein to investigate the dual excitationof a two degree of freedom spring-mass-damper system subjected to anapplied rotation rate. In doing so, an analytical formulation including mechanicalcoupling effects is extended into a generalized form, after which the amplitudeand phase responses of the mechanically uncoupled system are interpreted.The differences between the amplitude and phase measurement techniques areillustrated.Finally, the system is modelled numerically, and the scale factor of a hypotheticaldevice based on the phase-based detection method is optimized, subject toconstraints on the nonlinearity of the device, using constrained mathematicaloptimization techniques.

[发布机构] Stellenbosch University