A robust control based solution to the sample-profile estimation problem in fast atomic force microscopy

The atomic force microscope (AFM) is a powerful tool for imaging and manipulating matter at the nanoscale. An optimal control problem is proposed for the control of AFMs which includes the design of a sample-profile estimate signal in addition to the set-point regulation and resolution objectives. A new estimate signal for the sample profile is proposed and it is proved that the transfer function between the profile signal and the estimate signal is unity. The main contribution in comparison to existing designs is that there is no bandwidth limitation on estimation of sample profiles! Experimental results are presented to corroborate these results. Copyright © 2005 John Wiley & Sons, Ltd.