By Shannon Ghorbani, Mad City Labs, Inc.
The word “nanopositioner” is a generic, wide-ranging term used to describe different types of motor technology capable of positioning a stage within ranges of tens of nanometers, or even potentially single-digit nanometers. Often, the perception is these instruments are highly specialized and only useful in certain scenarios, but that presumption is inaccurate.
Users often believe that nanopositioners are primarily used when you need nanometer (or better) resolution. However, this approach overlooks some of the characteristics of nanopositioners and how they can be used as part of an integrated approach to motion control.
This article explores the nuances of nanopositioners, how they function, and the extent of their capability. Specifically, it addresses piezo nanopositioners (AKA piezo stages), so called because of the piezo electric actuator serving as their drive mechanism and differentiating them from positioning systems utilizing other forms of driving motor technology. We also examine how closed-loop feedback control can be applied to a piezo nanopositioner — significantly improving stability, resolution, and repeatability — to push the limits of user precision when controlling a platform at the nanometer scale.