Time-varying internal model-based tracking control for a voice coil motor servo gantry

This paper presents a time-varying internal model-based control algorithm for high precision tracking of frequency-varying trajectories on a Voice Coil Motor (VCM) actuated servo gantry system. A new internal model control structure is proposed with a parallel connection of the stabilizer, which facilitates the design of a low order time-varying stabilizer for the augmented time-varying system. Effectiveness of the proposed control design is validated with simulations and experiments on the VCM servo gantry system. The resulting controller demonstrates good tracking performance with tracking error around 2 μm (RMS) for frequency varying periodic signals with RMS value of 354 μm.