2004 & 2005 Best Paper
“Robust Two-Degree-of-Freedom Control of an Atomic Force Microscope”

G. Schitter  and A. Stemmer
Swiss Federal Institute of Technology, Switzerland
F. Allgöwer
University of Stuttgart, Germany
Issue：Vol. 6, No. 2, pp. 156-163, 2004

ABSTRACT

The performance of an atomic force microscope (AFM) is improved substantially by unitizing modern model-based control methods in comparison to a standard proportional-integral (PI) controlled AFM system. We present the design and implementation of a two-degree-of-freedom (2DIF)-controller to accomplish topography measurements at high scan-rates with reduced measurementcontroller operates the AFM system in a closed loop while a model-based feedforward controller tracks the scanner to the last recorded scan-line. Experimental results compare the actual performance of the standard PI-controlled AFM and 2DOF controller system. The new controller reduces the control error considerably and enables imaging at higher speeds and at weaker tip-sample interaction force.