Differential Sensitivity Analysis of a 3-DOF Vibratory Rate Micro Gyroscope

In this paper, a capacitive 3-DOF vibratory rate micro gyroscope with 2-DOF oscillator in the sense mode and 1-DOF in the drive mode was studied. A complete model of the micro gyroscope, including mechanical and electrical parts was utilized. Based on the graphical and differential sensitivity analyses methods, variations of the system parameters were analyzed. In the first step, governing equations of the micro gyroscope were derived. In order to simulate the sensor operation, working frequency has been determined and then, output voltage of the sensor versus changes in mechanical and electrical elements is studied. According to the sensitivity analysis results, secondary mass (m2), permittivity, length and width of the electrostatic capacitors, also DC and AC components of the actuation voltage have been clustered as the most sensitive parameters. Initial gap of the electrostatic capacitors and stiffness are fairly sensitive. Primary mass (m1), mass of the decoupling frame (mf), and young module are considered as non-sensitive parameters. Variations of the output voltage based on secondary mass (m2), stiffness and initial gap are completely non-linear and in some areas have severe slopes. Wise choices in selecting appropriate values for these parameters will lead to the better performance and more output voltage of the sensor