Piezoelectric MEMS Vibration Sensor Module for Machining Quality Prediction

In this work, a piezoelectric MEMS based vibration sensor with a unique gimbal shaped guard ring in differential electrical configuration has been designed for enhanced acceleration sensitivity in out-of-plane direction and reduced in-plane crosstalk. The Thin-film Piezo on Silicon (TPoS) accelerometer was fabricated using a GlobalMEMS Inc. PZT platform. This method makes use of the excellent piezoelectric property of the Lead Zirconate Titanate (PZT) thin-film along with low crystal defect property of single crystal silicon, thus ensuring a good combination of sensitivity, resolution, bandwidth, reliability, and lifetime. A system-level approach was adopted to integrate the MEMS device with a charge amplifier and a microcontroller. The device performance was compared with the standard reference accelerometer for 1-g load. The developed MEMS sensor module was further implemented for surface roughness prediction in a quartz polishing system using machine learning algorithm incorporating both the acceleration-time data and the feed rate of the polishing spindle.