Effect of Residual Stresses on a Micromachined Z-Axis Vibrating Rate Gyroscope

Abstract:

The design of mechanical structures depends upon characterizing the stress/strain state in these devices under the combined influence of both loading and residual stresses. The performance of the dynamic structures is strongly influenced by residual stresses. Understanding of the behavior of gyroscopes in presence of residual stresses and ability to relieve the stresses are essential for improving the performance. In this paper, we briefly analyze the cause of residual stresses. The effect of residual stresses on natural frequencies of the drive mode and sense mode is theoretically analyzed. The FE model of the z-axis gyroscope is built to investigate the relation between the frequencies and the residual stress by model analysis. Methods for residual stress relief are presented. The results of the simulation demonstrate that the performance of the gyroscopes with serpentine beams and stress relief slots can be improved significantly.

• Periodical: Key Engineering Materials (Volumes 295-296)
• Pages: 101-106
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.295-296.101
• Online since: October 2005
• Authors: A.P. Qiu, Y. Su, S.R. Wang, B.L. Zhou
• Keywords: Frequency, Residual Stress, Serpentine, Slot

References

[1] W.A. Clark: Micromachined Vibratory Rate Gyroscope (Department of Engineering-Electrical Engineering and Computer Science, Berkeley 1997).

[2] B. Xu et al.: Elements of Mechanical Vibration and Modal Analysis (Publishing House of Mechanical Industry, 1998).

[3] Trey A. Roessig et al.: IEEE International Frequency Control Symposium, 1997, p.778.

[4] W.A. Clark: Micromachined Vibratory Rate Gyroscopes, U.S. Patent, No. 6067858, (2000).

[5] W.C. Tang: Sensors and Actuators, Vol. A20 (1989), p.25.

[6] C. Tsou and W. Fang: J. Micromech. Microeng., 2000, p.34. 2000 4000 6000 8000 10000 -25 -20 -15 -10 -5 0 5 Output(V) Frequency(Hz) Fig. 9 Frequency response of the sense mode.