Error suppression circuit for micromachined gyroscope

In this paper, the quadrature error and in-phase error of micromachined gyroscope were analyzed in detail, and an electrostatic force feedback control scheme was presented to suppress the errors. The equivalent stiffness and damping in the sense mode generated by electrostatic feedback force were used to change the coupling between the two modes of the gyroscope. Thus the errors can be suppressed. A closed-loop detective circuit with feedback correction was designed and implemented, and the simulation results showed that the gain margin and the phase margin could reach 25 dB and 36.5° respectively. The effect of the error suprressing circuit was verified by spectrum analysis and performance testing. The errors were decreased by 50%, the nonlinearity of scale factor decreased from 0.24% to 0.09%, the bandwidth increased 15 Hz, and the bias stability increased by 1.3 times.