A virtual tapping-mode atomic force microscope

Tapping-mode atomic force microscope (TM-AFM) is currently the most widely utilized instrument for atomic-resolution imaging and nano-manipulation. However, the complex cantilever-tip dynamics has not been fully understood due to the inherent nonlinear property of tip-sample interaction. Experiments and analytical techniques are two basic methods to investigate the nonlinear effects, but they are either too costly or requires extremely advanced mathematical and physical knowledge to apply. In this paper, we present an alternative solution for this problem by constructing a virtual tapping-mode AFM system built in Matlab-Simulink environment. As demonstrated in the paper, the virtual AFM is capable of performing various classic experiments in AFM including approach-retract, sweeping frequency, PID-based amplitude regulation etc. It also provides a numerical platform for research work to explore new ambitious control strategies aiming at improving the scanning speed and precision of the AFM system.