A close-loop control approach to AFM scanner based on a hysteresis model

The scanner is the most important part of Atomic Force Microscope (AFM), which directly determines an AFMpsilas measuring capability. However, the scanner made of piezoelectric materials always exhibits significant hysteresis and nonlinearity, and the hysteresis will reduce the positioning precision of AFM and cause distortion in scanning images. In this paper, a hysteresis model is proposed to precisely describe the hysteresis curves. Experiment result shows that, actuated by a series of triangular-wave voltage, the predicting error of the model is less than 2%. A close-loop control system based on the model is also designed, which has better dynamic performance theoretically. The experiment result demonstrates that the nonlinearity of the system is less than 0.5%.