While Atomic Force Microscopes (AFMs) can provide high-resolution images with atomic scale resolution, the speed and actual quality of AFM images depend upon the overall dynamics of the AFM system. AFMs exhibit coupling effects across the axes of motion and the full multi-input, multi-output (MIMO) nature of the system should be taken into account in order to achieve higher speed and higher quality images. In this project, a few control architectures, with varying combinations of feedforward and feedback controllers, will be explored to determine the advantages and disadvantages of each architecture with respect to model uncertainty characteristics and model inversion control design techniques. Based upon these results, adaptive model-inverse based controllers will be developed for some architectures to enable good performance across all "plants" within a set of similar plants. The results of this research will demonstrate advanced control methods for nonminimum phase MIMO systems, with a particular focus towards enabling AFMs to be fast and behave like dependable instruments.
The Atomic Force Microscope (AFM) is one of the most versatile methods of imaging nanoscale structures. It is becoming a driving technology in nanomanipulation and nanoassembly and is playing a burgeoning role in the field of molecular biology. The behavior of current commercial AFMs varies considerably across AFM probes as well as changes in samples and environmental conditions. The variability causes commercial AFMs to not behave like reliable instruments, and this slows down and frustrates AFM users. The overall dynamics of AFMs can be improved by improving either the dynamics of the actuators themselves or by improving the control system. This project focuses on investigating, analyzing, and deriving control systems to increase the speed and image quality in AFMs, while working in close collaboration with a team of scientists and engineers at Agilent Technologies who will be simultaneously developing better actuators for AFMs.
A number of outreach programs are planned at the University of Colorado at Boulder, including several K-12 programs that seek to educate and interest students in the field of engineering, where AFMs will be highlighted as an example of an engineering tool used in many different applications.
