Research of a symmetrical decoupled dual-mass micro-gyroscope with an improved lever support system

Abstract

The structure design, simulation, fabrication, signal measurement and control of a symmetrical decoupled dual-mass micro-gyroscope (SDDMG) are presented in the paper. The two masses of the SDDMG are linked elastically not only in the drive mode but also in the sense mode and can be resonant driven simultaneously in in-phase and anti-phase mode even if there is fabrication error. The micro-gyroscope structure is designed and the operating principle of the improved lever support system is described detailedly. The modes of the SDDMG are controlled to optimize the acceleration sensitivity. The micro-gyroscope structure is simulated by Ansys software to optimize modes and the structure parameters. The DDSOG process is adopted for the fabrication of the micro-gyroscope structure. The frequency sweep results indicate that the modes have an in-phase drive frequency of 3328.8 Hz, an anti-phase drive frequency of 3530.8 Hz, an in-phase sense frequency of 3380.0 Hz and an anti-phase sense frequency of 3579.1 Hz. The signal processing circuit based on FPGA is implemented. The rotation rate sensitivity experiment exhibits a rate sensitivity of 15.13 mV/°/s. Comparing the acceleration sensitivities with that of the prevenient micro-gyroscope, the maximum acceleration sensitivity decreases by 3.18 times, which indicates that the mode optimization is viable. Finally, the Allan variance analysis shows that the device has a bias instability of 2.38o/h under the vacuum environment.