Date & Venue
Tuesday, 04 February 2020, 04:00pm
EF122
Abstract
The Atomic Force Microscope (AFM) has emerged as an indispensable
research tool in the development of nanoscience and nanotechnology.
Piezoelectrically actuated nanopositioning stages are widely employed in
AFMs to realize accurate the positioning of the sample-to-be-scanned,
due to several performance advantages such as fine resolution,
repeatability, controllability, fast response, etc. Triangular
trajectories, whose high-frequency components tend to excite the lightly
damped resonance of the employed nanopositioner and introduce
positioning errors, are extensively used to create the popular raster
scanning pattern. Scanning errors are further introduced by the
rate-dependent hysteresis inherent to the piezoelectric actuators
employed in the nanopositioners and the coupling effect to
another lateral scanning axis. Here, the repetitive control (novel type)
is incorporated to improve the tracking performance of both the lateral
scanning axes, providing the fundaments for high-speed scanning of AFM,
in which the tracking frequency up to 1587.3
Hz (triangular trajectory) and the scanning rate of 1000 Hz (raster
scanning) are achieved with e_rms≈0.5%.
Speaker Biography
Linlin Li is working toward the Ph.D. degree in mechanical engineering at Shanghai Jiao Tong University, Shanghai, China, since 2016. She visited the University of Aberdeen for 6 months from 1st May to 1st Nov. 2019. She is currently a visiting Ph.D. student at the University of Newcastle. Her research interests include modeling and control of high-bandwidth nanopositioning stages and its applications to atomic force microscopes.