Real-time state estimation and fault detection for controlling atomic force microscope based nano ma

Abstract

The main problem of Atomic Force Microscope (AFM) based nanomanipulation is the lack of real-time visual feedback. Although the model based visual feedback can partly solve this problem, the incorrect display caused by the uncertainties in the nano-environment often leads to a failed nanomanipulation. In this paper, a general strategy with three-level structure is proposed to overcome this problem. With this three-level strategy, the incorrect display can be not only real-time detected, but also on-line corrected. The difficulty to implement this strategy is that there is no continuous way to describe and model the system since both discrete and continuous commands are involved. A Petri-net based method is proposed to organize this strategy such that task scheduling, which usually deals with discrete events, as well as task planning, which usually deals with continuous events can be treated in a unified framework. This Petri-net organized strategy provides general instructions to AFM based manipulation for displaying a visual feedback which can be as close as possible to the true environment. The experimental results presented in the paper demonstrate the advantage of the proposed strategy. It also shows the increased efficiency of the AFM based nanomanipulation. Copyright © 2007 International Federation of Automatic Control All Rights Reserved.