High-Speed AFM Image Scanning Using Observer-Based MPC-Notch Control

This paper presents the design and experimental implementation of an observer-based model predictive control scheme with a notch filter to achieve accurate tracking and fast scanning for an atomic force microscope (AFM). The proposed controller reduces the tracking error by improving the damping of the resonant modes of the AFM piezoelectric tube scanner (PTS). The design of this controller is based on an identified model of the PTS. A Kalman filter is used to obtain full-state information in the presence of position sensor noise. A comparison of the experimentally obtained scanned images using the proposed controller and the existing AFM PI controller is given. The experimental results demonstrate the efficacy of the proposed controller.