Displacement and Force Self-Sensing Technique for Piezoelectric Actuators Using a Nonlinear Constitutive Model

This paper describes a new self-sensing technique for piezoelectric actuators that estimates both displacement and force from voltage and charge measurements. The novelty of this technique lies in the use of a constitutive model with nonlinear capacitance and an exponential hysteresis model. The advantage of the presented self-sensing technique over similar techniques in the literature is that it only requires one parameter identification experiment and its hysteresis model is computationally efficient. The control performance of the self-sensing technique is evaluated in a sensorless displacement and force control structure. Validation experiments are carried out on a two degree of freedom test setup that mimics micropositioners by generating simultaneously varying displacements and forces. Less than 3% absolute average errors are obtained for both displacement and force.