Effect of Axial Force on the Performance of Micromachined Vibratory Rate Gyroscopes

Sensors

Zhanqiang Hou²  Dingbang Xiao²  Xuezhong Wu¹  Peitao Dong²  Zhihua Chen²  Zhengyi Niu² 

[1] College of Mechanical Engineering and Automation, National University of Defense Technology, Changsha, Hunan Province, 410073, China;

关键词: micromachined vibratory gyroscope;    thermal stress;    resonant frequency;    slanted beam;    temperature characteristics;    anodic bonding;   

DOI  :  10.3390/s110100296

来源: mdpi

【 摘 要 】

It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F) beam and the other one was suspended with a clamped-clamped (C-C) beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF) due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.