Kalman filter enabled high-speed control of a MEMS nanopositioner

We demonstrate a novel tracking controller formulation based on a linear time-varying Kalman filter to regulate amplitude and phase of a reference signal independently. The method is applicable to sinusoidal references such as spiral, cycloid and Lissajous trajectories which are commonly used for imaging in high-speed Atomic Force Microscopy (AFM). A Microelectromechanical Systems (MEMS) based nanopositioner, whose fundamental resonance frequency is dampened with an additional damping feedback loop, is employed. For a scan range of 2µm, we demonstrate experimental tracking of sinusoids with frequencies as high as 5kHz, well beyond the open-loop fundamental resonance, with a tracking error of only 4.6 nm.