Multiphysics & Parallel Kinematics Modeling of a 3DOF MEMS Mirror

This paper presents a modeling for a 3DoF electrothermal actuated micro-electro-mechanical (MEMS) mirror used to achieve scanning for optical coherence tomography (OCT) imaging. The device is integrated into an OCT endoscopic probe, it is desired that the optical scanner have small footprint for minimum invasiveness, large and flat optical aperture for large scanning range, low driving voltage and low power consumption for safety reason. With a footprint of 2mmx2mm, the MEMS scanner which is also called as Tip-Tilt-Piston micromirror, can perform two rotations around x and y-axis and a vertical translation along z-axis. This work develops a complete model and experimental characterization. The modeling is divided into two parts: multiphysics characterization of the actuators and parallel kinematics studies of the overall system. With proper experimental procedures, we are able to validate the model via Visual Servoing Platform (ViSP). The results give a detailed overview on the performance of the mirror platform while varying the applied voltage at a stable working frequency. The paper also presents a discussion on the MEMS control system based on several scanning trajectories.