A tunable threshold pressure sensor based on parametric resonance of a microbeam subjected to electrostatic levitation is proposed. Parametric excitation can trigger a large amplitude vibration at twice the natural frequency if the magnitude of the driving force is large enough to overcome energy loss mechanisms in the system such as squeeze film damping. This causes a temporarily unstable response with a significant gain in oscillation amplitude over time until it is eventually capped by nonlinearities in the force or material or geometric properties. The instability divides the frequency region into two regions: distinct responses bounded by the system non-linearity, and trivial responses with very low oscillation amplitudes. It is shown experimentally that the appearance of parametric resonance depends on the pressure, which influences the amount of energy loss from squeeze film damping. Therefore, the distinct difference in the vibration amplitude can be used to detect when the pressure passes a threshold level. The activation of parametric resonance also depends on the amplitude of the driving force (). This voltage amplitude can be set to trigger parametric resonance when the pressure drops below a predetermined threshold. A reduced-order model is developed using the Euler–Bernoulli beam theory to elucidate the non-linear dynamics of the system. The simulation results from the mathematical model are in good agreement with the experimental data. The advantages of the proposed sensor over pull-in based sensors are its reliability and improved resolution from a large signal-to-noise ratio.

提出了一种基于静电悬浮的微束的参数共振的可调阈值压力传感器。如果驱动力的大小足够大，可以克服系统中的能量损失机制（如挤压膜阻尼），则参量激励可以以自然频率的两倍触发大振幅振动。这会导致暂时不稳定的响应，并随着时间的推移大幅增加振荡幅度，直到最终被力，材料或几何特性的非线性所限制。不稳定性将频率区域分为两个区域：以系统非线性为边界的不同响应，以及振荡幅度非常低的琐碎响应。实验表明，参数共振的出现取决于压力，这会影响挤压膜阻尼产生的能量损失量。因此，振动幅度的明显差异可用于检测压力何时超过阈值水平。参数共振的激活还取决于驱动力的幅度（）。可以将该电压幅度设置为在压力下降到预定阈值以下时触发参数共振。使用欧拉-伯努利光束理论开发了降阶模型，以阐明系统的非线性动力学。数学模型的仿真结果与实验数据吻合良好。与基于引入传感器的传感器相比，所提出的传感器的优势在于其可靠性和大信噪比下提高的分辨率。