Identification and control of piezoelectric benders for skin mechanical impedance estimation

This paper presents an integrated probe, designed to measure the rheological properties of the skin in situ. It includes two piezoelectric bender actuators and strain gauges as sensors. The advantage of the proposed probe is that the measurements of tip force and displacement are accomplished without external devices. A feedback voltage control is applied to control the vibration amplitude of the piezoelectric benders. Through feedback from integrated strain gauges, the displacement control is achieved. As shown in the simulation, the closed-loop system is robust to disturbance and uncertainty. The proposed probe may be used to measure skin mechanical impedance.