An approach to modeling and on-line identification for piezoelectric stack actuator

The piezoelectric stack actuator used in Scanning Probe Microscopes (SPMs) always exhibits significant hysteresis and creep. The hysteresis and creep will reduce the positioning precision and produce the distortion in scanning images. Therefore it is necessary to develop a model with sufficient accuracy and stability to characterize the nonlinearities of the piezoelectric stack actuator. In this paper, a novel hysteresis and creep model and a method for on-line identifying parameters of this model are proposed. Experiment result shows that, actuated by triangular-wave voltage, the predicting error using the proposed model is less than 2%, which is reduced by an order of magnitude comparing with the error directly predicted using input voltage. The validity of this method is demonstrated by experiment result.