Nonlinear Hysteresis Compensation of Piezoelectric Ceramic Actuators

The piezoelectric ceramic actuator generates a small displacement but a large force as well as a fast time response. Accordingly, they are commonly incorporated in the design of micropositioning xy-tables, ultrasonic motors and impact printer heads. Piezoelectric ceramics are ferroelectric, and they are fundamentally nonlinear in their response and show a significant hysteretic loop to the applied voltage signal, which sometimes causes a serious problem in their application as a linear actuator. This paper presents a study on the linear drive of nonlinear piezoelectric ceramic actuators. The experimental results show that the expansion of ceramic actuator can approximately be represented by a third-order polynomial of the applied voltage. Moreover, the hysteretic loop is significantly reduced if the input voltage to the actuator is provided again in the form of a third-order polynomial. The proposed linear drive method is first investigated theoretically. Then, a simple nonlinear preamplifier is assembled based on the proposed scheme. An experimental study is conducted to see the effectiveness of the amplifier. It is shown that the hysteretic loop on the actuator displacement disappears when the pre-amplifier is installed between the voltage generator and the DC amplifier.