Tracking of spiral trajectories beyond scanner resonance frequency by a MEMS nanopositioner

This paper presents a novel application of internal model control (IMC) for high-precision tracking of spiral reference signals generated by single-tone sine waves. In contrast to the existing spiral tracking control methods, the IMC approach provides zero steady-state tracking error for linear-time-invariant plants. An application of the proposed method is demonstrated with a two-axis microelectromechanical system (MEMS) stage that has a dominant resonance frequency of 1.3 kHz. Using a reference sinusoidal frequency of 1.4 kHz, the stage can scan a 16 μm-diameter area within 55ms with a root-mean-squared (rms) tracking error of 20nm.