A new control strategy for high-speed atomic force microscopy

An advanced controller consisting of a feedback and feedforward part is presented to improve the performance of an atomic force microscope (AFM) enabling topography measurements at higher scan rates with a reduced measurement error. The tip–sample interaction force is held constant by an H∞-controller while the scanner is simultaneously tracked to the topography of the last recorded scan line by a model-based feedforward controller. The designed controller is implemented on a commercial AFM system to compare the performance to a standard proportional integral controlled AFM. The new controller reduces the measurement error and enables imaging at higher speeds and at smaller tip–sample interaction forces.