Analysis and Design of Closed-Loop Detection Technique for Micro-Grating Accelerometer

A novel closed-loop control method with Pound-Drever-Hall modulation technology is proposed to optimize the linearity and detection accuracy of micro-grating accelerometer in practical application. The closed-loop error is modulated to a high frequency for eliminating the direct current component of the interference intensity and stray light disturbance. After phase sensitive detector and filter of demodulation, the closed-loop error signal is obtained with high signal-to- noise ratio. Based on the principle of designed modulation and demodulation method, the dynamic model of closed-loop micro-grating accelerometer is established considering the nonlinear interference effect, optical intensity fluctuation, and unavoidable noise. Then, a robust control algorithm is designed to optimize the performance of micro-grating accelerometer. The experimental results demonstrate that the micro-grating accelerometer has linearity within 0.35% and the bias stability 0.2 mg, which validate the effectiveness and usefulness of the proposed closed-loop detection scheme.