Similarity-based Feedback Control for Linear Operation of Piezoelectric Actuators

The positioning accuracy of piezoelectric transducers is limited by nonlinearities such as hysteresis and creep. Improving the accuracy by feedback control is not always desired or possible due to the difficult integration of a position sensor. The method presented in this paper uses two piezoelectric transducers of the same type, to linearly operate one of them without a sensor. The nonlinear voltage-displacement relation of two transducers is analyzed and compared. It is shown that their nonlinearities are almost identical. The displacement of one of the transducers is measured and used to control the displacement of the other one, reducing the positioning error due to nonlinearities for a triangular reference signal from 9.2% to 0.3% of the actuation range.