An Air-Electronic Converter With MEMS Quartz Resonator and Bi-Chamber Structure for Air Gauging Sensor

As a crucial component of air gauging sensors in intelligent CNC machine tools, air-electronic converters directly influence measurement accuracy. Nevertheless, conventional designs suffer from performance limitations due to undesirable dynamic/temperature characteristics in pressure conversion elements and accuracy loss during analog-to-digital (A/D) conversion. Aiming at this critical issue, a quasi-digital output micro-electromechanical system (MEMS) resonator-based air-electronic converter is presented and characterized in this article. The converter employs a gas conversion element to transform slot width/displacement into chamber pressure, utilizing a bi-chamber structure (feeding and measuring chambers) to suppress air supply fluctuations. A differential resonant pressure-sensing unit, incorporating two quartz double-ended tuning fork (DETF) resonators, is proposed to convert chamber pressure to frequency signals while compensating for temperature-induced errors. Characterization results demonstrate the linearity of ≤ 0.5 % full scale (FS), an actual resolution of 0.04 µm, and enhanced stability through the combined output of four DETF resonators. An expanded uncertainty of 0.059 µm in displacement measurements confirms the device’s repeatability and reliability. This work advances the performance of air-electronic converters by enabling direct quasi-digital output and improved stability, offering a promising solution for high-precision air gauging sensors.