Improvement of transient response for drive loop of microgyroscope using 2-DOF PID controller

This paper presents a novel control strategy for the drive loop of microgyroscope based on two degree-of -freedom (2-DOF) PID controller. Compared with the conventional AGC-1DOF PID controller, the proposed AGC-2DOF PID controller can realize self-oscillation of the microgyroscope with improved transient response by moving some portions of the proportional and the derivative components of the single PID controller to the feedback path. A tuning fork micromachined gyroscope is fabricated to verify the revised controller. The resonant frequency and the quality factor of the drive mode are measured to be 2.528 kHz and 84 at the atmosphere, respectively. The test results demonstrate that the percent overshoot is reduced from 36.2% (1DOF PID) to 4.35% with approximately 3.35% improved in setting time. The signal-to-noise ratio (SNR) of the excitation signal is larger than 88dB. The scale factor is measured to be about 33.5mv/deg/s with the non-linearity about 0.5% within the range of ±400deg/s.