Hysteresis Compensation of an Open-Loop Piezoelectric Actuator for Interferometric Applications

In the present paper a piezoelectric actuator realized for interferometric applications is described, together with a numerical model to simulate its hysteretic behaviour. The actuator is an open-loop device made up of three PZT ceramics glued into a stainless steel case and connected directly to the parallel port of a personal computer by an OEM control electronics. It consists of a 16 bit D/A converter whose voltage is fixed by the parallel port, a charge amplifier which provides the voltage to the PZT ceramics and a current divider for the control of the voltage on each channel. The layout based on three active elements has allowed to obtain a device which is able to perform a straight expansion with a negligible tilting, a desirable feature for an actuator used for interferometric applications. The hysteretic behavior of the actuator was simulated by a numerical model, based on the Prandtl-Ishlinskii hysteresis operator, which shows a high capability to predict the input-output response at any level of the input signal, and it is efficient enough for use in real-time applications.