Analysis of temperature variation influence on damping coefficient and Q-factor of 2-DOF vibratory rotational velocity sensor

Temperature is the most important factor that influences the operation performance of the MEMS (Microelectromechanical System). It affects either the geometry deformation or the physical properties of the materials of which the whole device is composed. For that reason, device designers should consider the target application of the device and environmental limitations. In the paper, the authors pointed out the following considerations essential under temperature impact on the whole device: spring coefficients of resonator and accelerometer variation, total damping coefficient change (consisted of slide and squeeze damping), variation of the thermal expansion coefficient as the temperature varies, Young's modulus temperature dependency, geometry deformation.The authors in this paper show a method of simulation in a multitool environment gyroscope with temperature dependence. The facts depicted above were an entry point to create models in COMSOL (2-Degree-of-Freedom) with two masses: inertial central mass and inertial frame. Based on the calculation of natural frequencies, a model representing operation of the gyroscope was created in the Simulink environment. To automate the calculation for different temperatures, the Simulink model was supported with MATLAB script. The results obtained from the FEM (Finite Element Method) simulation were compared with those obtained from 2nd-order equation results. Moreover, FEM simulation results were used to calculate the total spring coefficient, which is very complex to calculate analytically with the use of well-known formulas. Because the Q-factor is a crucial quantity in the evaluation of device performance, it was calculated as a dependency for both the resonator and accelerometer. The natural frequency and Q-factor are used to simulate dynamics of the gyroscope and compare the magnitude and phase for different geometry configurations to find the optimal geometry for good mode matching.