Improving the precision of micromachined tuning fork gyroscope

The various error sources for micromachined tuning fork gyroscope are the main obstacle to improving its performance. In this paper we discuss in detail the approaches to suppressing these error sources in order to improve the gyroscope's performance. In this paper, we explain in much detail how to suppress these error sources but here we give only a briefing of it. The coupling between the displacement current in drive mode and the output current in detection mode was largely canceled by using split electrode at centre electrode. Then the drive voltage's contamination of displacement current through the spray capacitance was suppressed by half frequency drive scheme, which means the frequency of drive voltage is at one half of system's natural frequency. The comb levitation was alleviated through the trench around the interleaved comb area in glass substrate. The mismatch between the two drive capacitors was compensated through the automatic adjustment of drive voltage's amplitude to equalize the charge induced on the proof mass. Finally, the quadrature error term was largely removed by synchronous demodulation. Theoretical analysis results show preliminarily that these approaches can improve the gyroscope's performance effectively.