A high-resolution resonant torque sensor based on MEMS quartz resonator

Abstract Due to the continuous miniaturization of Micro-Electro-Mechanical System (MEMS) devices, investigations on the mechanical properties of micro-scale materials, especially the torsion properties, have attracted increasing attention. This paper reports a resonant torque sensor based on MEMS quartz resonator for torsion test of micro-scale materials. The sensor consists of an ICP etched silicon structure and two quartz double-ended tuning fork (Q-DETF) resonators. An experiment system with the functions of microscopic observation and precise positioning has been built, which can be used for the calibration of the torque sensor and the torsion experiment of micro-scale materials. In the atmosphere at room temperature (25℃), the frequency stability of the sensor was up to 11.68 ppb. The scale factor of the sensitive direction of the sensor reached 253.3 mHz/μN, and the cross-sensitivity was minimized to 2.1 %. The experimental results showed that the resolution of the torque sensor was higher than 35.82 pN m. The electrolytic pure copper foil was used to carry out torsion tests in the range of 0°-8°. The loading and unloading tests proved our sensor owned high repeatability and low hysteresis of less than 1%.