Design and analysis of an integrated 3-DOF sensor for tracking in-plane motion

In this paper, we present design and analysis of a three-degree-of-free sensor, which integrates a lateral axis tuning fork angular rate gyroscope with a two-degree-of-free accelerometer. The sensors for integrating are designed to reduce noises and improve the sensitivity by exploring mechanical couple springs. The design of the devices is carried out by simulating their mechanical behavior with the FEM method using ANSYS software and SIMULINK Matlab. The frequency difference between operation modes and parasitic ones in the gyroscope and accelerometer are 50% and 58%, respectively. The sensitivity of gyroscope and accelerometer determined from the SIMULINK model and FEM analysis are 11fF/deg./s and 11.5 fF/g, respectively. The sensors have been designed for measurement in a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit.