Sensorless Parameter Estimation of Piezoelectric Elements with the Consideration of the Internal Resistance Only Based on Impedance Measurement

Abstract

A sensorless parameter estimation method for piezoelectric structures is proposed. Compared with the conventional method, this paper introduces a lossy electrical model that takes the internal resistance of piezoelectric structures into consideration. A new electrical impedance transfer function for piezoelectric structures is obtained. Parameter estimation method using linear and nonlinear frequency-domain least squares methods are discussed only based on impedance measurement. In the experiment for estimating parameters, the electrical impedance of the piezoelectric element is highly affected by the relative humidity. It is verified that the frequency response of the identified model shows a good agreement with that of the measured impedance, in contrast to that the conventional model could not perform accurate estimation. The accuracy of the estimated parameters are also investigated by damping experiments with a tuned LR shunt circuit.