Performance enhancement of a closed-loop accelerometer tuned close to its instability regime

A closed-loop micro-accelerometer is presented where its instability regime is used in order to enhance its static gain. Sensitivity functions are increased in low frequencies and therefore any acceleration applied on the proof mass is better rejected than in conventional closed-loop approach. To design a robust controller, an identification procedure of the instable structure is presented as well. Finally the signal reconstruction of the applied acceleration is made trough a Kalman filter. Simulation results are given and demonstrate the efficiency of the proposed approach.