-A A +A
A novel type of linear extensometer with exceptionally high resolution of 4 nm based on MEMS resonant strain sensors bonded on steel and operating in a vacuum package is presented. The tool is implemented by means of a steel thin bar that can be pre-stressed in tension within two fixing anchors. The extension of the bar is detected by using two vacuum-packaged resonant MEMS double-ended tuning fork (DETF) sensors bonded on the bar with epoxy glue, one of which is utilized for temperature compensation. Both sensors are driven by a closed loop self-oscillating transresistance amplifier feedback scheme implemented on a PCB (Printed Circuit Board). On the same board, a microcontroller-based frequency measurement circuit is also implemented, which is able to count the square wave fronts of the MEMS oscillator output with a resolution of 20 nsec. The system provides a frequency noise of 0.2 Hz …
Publication date: 
5 Jun 2011

Matteo Ferri, Luca Belsito, Fulvio Mancarella, Luca Masini, Alberto Roncaglia, Jize Yan, A Ashwin Seshia, J Zalesky, K Soga

Biblio References: 
Pages: 1056-1059
2011 16th International Solid-State Sensors, Actuators and Microsystems Conference