Extended lumped parameter electromechanical model of piezoelectric actuators

The lumped parameter electromechanical model of piezoelectric actuators, proposed former in the literature, is extended by the state-varying capacitance and Voigt-Kelvintype linear creep effect. This relates the converse piezoelectric effect, i.e. actuator displacement, to the remnant polarization of piezo-ceramic and associated creeping charge flow. The proposed modeling extension interconnects both the electrical and mechanical domains and provides a physically reasonable cause-effect relationship of the creep effect. Furthermore, the role of the initial hysteresis state, often omitted when modeling the piezoelectric actuators, is emphasized and explained in details, while using the play- and stop-type hysteresis operators. A series of experimental model verification are accomplished on the standard piezoelectric stack actuator when measuring the controllable input voltage and output displacement.