Development of a tunable resonant accelerometer with self-sustained oscillation loop

In this paper, presented are a resonance type accelerometer, its implementation and results of performance test. The structure and principle of resonance type accelerometer are illustrated concisely. A pure surface micromachining technology is used for the structure manufacturing. Fundamental idea of this sensor is to detect variation of effective stiffness from parallel-plated electrostatic resonator. Since resonant accelerometer needs to keep track of the system's resonance point, a feedback loop called self-sustained oscillation loop is designed. The resonant point and its stability robustness are analyzed using nonlinear control methodologies, i.e., describing function method and extended Nyquist stability criterion. Environmental test and theoretical analysis confirmed that the oscillation loop is very robust to external disturbances.