Programmable synchronization enhanced MEMS resonant accelerometer

Abstract

Acceleration measurement is of great significance due to its extensive applications in military/industrial fields. In recent years, scientists have been pursuing methods to improve the performance of accelerometers, particularly through seeking new sensing mechanisms. Herein, we present a synchronized oscillator-based enhancement approach to realize a fivefold resolution improvement of a microelectromechanical resonant accelerometer. Through the unidirectional electrical coupling method, we achieved synchronization of the sensing oscillator of the microelectromechanical resonant accelerometer and an external reading oscillator, which remarkably enhanced the stability of the oscillation system to 19.4 ppb and the resolution of the accelerometer to 1.91 μg. In addition, the narrow synchronization bandwidth of conventional synchronized oscillators was discussed, and hence, we propose a novel frequency automatic tracking system to expand the synchronization bandwidth from 113 to 1246 Hz, which covers the full acceleration measurement range of ±1 g. For the first time, we utilized a unidirectional electrical synchronization mechanism to improve the resolution of resonant sensors. Our comprehensive scheme provides a general and powerful solution for performance enhancement of any microelectromechanical system (MEMS) resonant sensor, thereby enabling a wide spectrum of applications.

Sensors: exploiting synchronization in developing high-resolution accelerometers

Researchers in China have first time exploited the natural phenomenon of synchronization into practical sensor design, which significantly enhanced the resolution of microelectromechanical systems (MEMS) accelerometers. A team led by X.W. and Z.J. at Xi’an Jiaotong University achieved synchronization of the sensing oscillator in the accelerometer and an external reading oscillator through the injection locking. The synchronization leads to a fivefold boost in the resolution of the accelerometer. The team also developed a frequency-tracking system to break through the limitation of the synchronization range thereby enabling the device to work in a wider dynamic range. In addition to the direct application in accelerometers, the technique can also be used to improve the performance of other MEMS resonant sensors.