Liu's blog

A systematic characterization of the motion and friction of a linear bearing with rolling elements used for nanopositioning reveals an explicit distinction of static and rolling friction. The effects

The German Academic Exchange Service (DAAD) - in cooperation with science organizations in North America and Germany— is to invite undergraduate students from the US and Canada in the fields of biology, chemistry, physics, earth Sciences and engineering to apply for a summer research internship in Germany. RISE summer placements take place with research groups at universities and top research institutions across Germany. The RISE interns are matched with a doctoral student whom they assist and who will also serve as their mentor. This program is funded by the Federal Ministry of Economics and Technology as part of the European Recovery Program (ERP).

More details at http://www.daad.de/rise/en/1.html.

Most friction models for automatic control are targeted for the macro world, and are of questionable value for the motion control of the high precision positioing stages. We published a paper recently in Technishes Messen (TM) on a study of the friction behavior in the moving range of micrometers. It provides info for the development of friction models targeted for the motion control in high precision engineering.

The following is the abstract, and the full paper can be downloaded from http://www.atypon-link.com/OLD/doi/abs/10.1524/teme.2006.73.9.500

ABSTRACT Most friction models for automatic control are targeted for the macro world, and are of questionable value for the motion control of the nanopositioning and nanomeasuring machine (NPM) system. We present the frictional behaviour of some selected materials, coatings, lubricants, and bearings tested under running conditions similar to a NPM system. Continuous change of surface properties results in various friction characteristics, which substantiate the further development of tribological coatings, particularly for vacuum applications. We emphasize the system engineering approach in developing friction models, which combines fundamental knowledge of surface science, materials science, and its applications in design, construction and automatic control.