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Abstract: Micromachined
z-axis vibrating rate gyroscopes we design are fabricated by the
dissolved wafer process (DWP). Residual stresses are developed in
mechanical parts of gyroscopes due to the fabrication process. The
effect of residual stresses on the natural frequencies of the drive mode
and sense mode is theoretically analyzed. Then, the FE model of the
z-axis gyroscope is built to simulate the relation of the frequencies
and residual stress by model analysis. The simulation results and
experiments demonstrate that the outer flexure beams fabricated by DWP
are subjected to tensile force, and the tensile stress value is about
20~30 MPa. The methods of the residual stress relief are presented and
an improved z-axis gyroscope is designed. The experiment results of the
improved z-axis gyroscope demonstrate that the performance of the
gyroscopes with serpentine beams and stress relief slots will greatly
improve.
Key
words: Residual
stresses Mechanical sensitivity Serpentine beam
Stress relief slot
CLC No: U666.12
Received
20040406, received in revised form 20050107
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