Modeling and Control of AFM-based Nano-manipulation Systems

This paper develops a model and control scheme for nano-manipulation systems based on atomic force microscopes (AFM). The model includes the micro-cantilever's and piezotube actuator's coupled dynamics. An identification-based controller is proposed for piezotube scanner positioning accounting for the piezotube's nonlinear sensitivity and axes coupling. A novel robust adaptive controller is developed to compensate for large parametric uncertainties including time varying and switching parameters due to probe-surface contacts as well as time varying and impulsive forces due to contact and impact. Discussions and simulations are presented for typical nano-manipulation tasks.