A Quasi-Zero Stiffness MEMS Accelerometer With Wide Open-Loop Dynamic Range

Quasi-zero stiffness MEMS accelerometers can achieve high-resolution through enhanced sensitivity, but their dynamic range is typically limited. In this work, we propose a quasi-zero stiffness MEMS accelerometer with wide open-loop dynamic range, based on a novel electrothermally tunable stiffness mechanism. The mechanism consists of two identical curved beams with opposite curvature, and two identical folded beams, all connected in parallel to the proof mass. The curved beams are electrothermally heated to the buckling state, their negative stiffness cancels the positive stiffness of the folded beams, resulting in quasi-zero stiffness over a large linear displacement range at the as-fabricated position. The experimental results demonstrate that under a heating voltage of 7 V, the accelerometer sensitivity increases by 39.5 times (6.95 V/g), the noise floor decreases by 98.12% (510 ng/Hz at 5 Hz), while maintaining an open-loop dynamic range of ±1 g. This work demonstrates promising results in improving the noise floor of MEMS accelerometers while maintaining a wide open-loop dynamic range, offering the potential for unprecedented performance.[2024-0217]