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G. Schitter, R. Stark, A. Stemmer:
"Fast contact-mode atomic force microscopy on biological specimen by model-based control";
Ultramicroscopy, 100 (2004), 253 - 257.

The dynamic behavior of the piezoelectric tube scanner limits the imaging rate in atomic force microscopy (AFM).In
order to compensate for the lateral dynamics of the scanning piezo a model based open-loop controller is implemented
into a commercial AFM system.Additionally, our new control strategy employing a model-based two-degrees-offreedom
controller improves the performance in the vertical direction, which is important for high-speed topographical
imaging.The combination of both controllers in lateral and vertical direction compensates the three-dimensional
dynamics of the AFM system and reduces artifacts that are induced by the systems dynamic behavior at high scan rates.
We demonstrate this improvement by comparing the performance of the model-based controlled AFM to the
uncompensated and standard PI-controlled system when imaging pUC 18 plasmid DNA in air as well as in a liquid
environment.

Atomic force microscopy