A PMUT-based Ultrasonic Probe Used for Contact Force Sensing

This work conducts systematic research on the design, optimization and application of piezoelectric micromachined ultrasonic transducers (PMUT) based ultrasonic probe. And it is the first time for PMUT used in contact force sensing. The PMUT chip consists of a pair of concentrically aligned circular and annular arrays used for receiving and emitting ultrasound, respectively. It achieves an emitting sensitivity of 1200 Pa/V. And the analytical model results achieve a good agreement with the experimental results, which only have relative errors of 8.8% and 6.3% in central working frequency and fractional bandwidth, respectively. Finally, an application experiment is carried out for contact force sensing, which achieves a maximum measuring sensitivity of -111 N/dB.