Adaptive Prefilter Design for Control of Quasistatic Microscanners

This paper describes an open loop control approach with analog impedance feedback damping for quasistatic MEMS microscanners based on electrostatic comb transducers. The control task is determined by high dynamic input trajectory following in the presence of an extremely lightly damped mechanical mass-spring system with nonlinear electromechanical characteristics. The approach presented in this paper makes use of a model-based design approach resulting in a nonlinear adaptive prefilter for optimally preshaping of customized trajectory inputs. The open loop control is augmented by an easy to implement resistive analog impedance feedback scheme that introduces electromechanical damping and increases robustness against physical parameter uncertainties of the MEMS microscanner assembly. The paper outlines the underlying MEMS microscanner technology, it describes the mathematical model based on ANSYS computation, and it discusses in detail the proposed control concepts. Simulations and experimental results prove the applicability of the control approach.