Prandtl-ishlinskii model-based hysteresis compensation of a piezoelectric scanner for atomic force microscopy

Hysteresis is an intrinsic property associated with all piezoelectric actuators, and various techniques for overcoming this disadvantage have been investigated in the past. In this paper, we present a simple way of compensating for hysteresis in a commercial piezoelectric scanner by using the Prandtl-Ishlinskii (PI) model-based feedforward method. The adopted method uses premeasured input-output data for a scanner with no control to obtain forward and inverse models to compensate for the hysteresis. The output from the inverse model is then used to drive the scanner. The model was validated by performing scans with and without compensation in an atomic force microscopy setup. The results confirm that the hysteresis was successfully compensated for, and the tracking errors were reduced greatly, thereby demonstrating the effectiveness of the feedforward compensation method. The proposed method has a potential to improve the imaging speed of an atomic force microscope because the scanner is not operated in a closed-loop control. Also, the extra sensor components and electronics associated with the closed-loop control can be eliminated, resulting in a simpler hardware setup.