Resonance supression of high Q particle accelerometer

The noise floor of high-performance accelerometers is conditioned by the vacuum pressure inside the sensor package. However, less than atmospheric pressure introduces a lower level of damping to the sensor's mechanical structure, resulting in a large static displacement at resonance. Consequently, this thesis aims to develop a closed-loop system to suppress the displacement of an underdamped accelerometer developed at Intelligent Sensing Laboratory (ISL) and prevent mechanical and electrical failure. This research proposed two controllers, negative derivative feedback (NDF) and positive position feedback (PPF), which offer high gain exclusively at resonance frequency to establish a closed-loop system. Then, controllers are implemented and tested at various vacuum levels to validate their effectiveness. When NDF was employed in the closed-loop, static displacement of the proof mass was reduced by 85 percent, compared to the highest 63 percent reduction when PPF was used. Another issue addressed in this work is the actuator effort. The ISL accelerometer has a substantial mass, which sets it apart from other accelerometers on the market in terms of performance metrics. However, controlling a high inertia-based system would necessitate higher energy. A novel system architecture based on electrode function switching is also presented to address this issue.