The Estimation and Compensation of the Loop-Parameter-Drifting in the Digital Close-Loop Quartz Flexible Accelerometers

There have been increasing demands for the long-term performance retention of the Quartz Flexible Accelerometers (QFA), extensively employed in the Inertial Navigation System (INS). Considering the convenience of conducting the parameter identification and control algorithm, the Digital Close-Loop QFA (Digital-QFA) is established to improve the long-term performance. Based on the model of the entire close-loop system, the interfering factors relating to time are analyzed in detail, both in the forward channel and the feedback channel. Two schedules are proposed to estimate the gain variation, utilizing the modulating signal and the feedback signal separately. According to the reference gain settings in ideal conditions, the forward and the feedback gain drifting of the system are calibrated online through the adjustment of the digital controller and the reference voltage of the DA-chip, separately. The simulation experiments show that about 90.26% of the gain-drifting could be estimated and about 87.56% of the output error of the accelerate could be restrained. Consequently, the proposed schedules could promote the long-term stability of the Digital-QFA significantly.