High-speed spiral nanopositioning

Nanometer-precise positioning at ultra-high velocities is a major challenge for rapidly emerging applications that use scanning probes in order to observe and alter the properties of materials down to the nanoscale. Typical examples include surface imaging, nanolithography and data storage. For example in probe-based data storage, constant linear velocity along the scan trajectory is required, in order for storage operations to be feasible. In this paper, a spiral-enhanced tracking control architecture is presented for the constant linear velocity spiral case. The proposed controller exploits the spire-wise narrowband frequency content of the reference signal, enabling very high speed and accurate positioning. The tracking performance and high-frequency operation are corroborated with experimental results from a piezo-actuated nanopositioner with magneto-resistance-based position sensors.