A Visually Servoed MEMS Manipulator

This paper reports on a visual servoing system capable of 2DOF nanopositioning using a novel multi-axis electrostatic MEMS (MicroElectroMechanical System) device. The high aspect ratio micromanipulator was fabricated using a high yield process with Deep Reactive Ion Etching (DRIE) on Silicon-On-Insulator (SOI) wafers, which produces larger electrostatic forces and requires lower actuation voltages compared to most existing electrostatic microactuators. A real-time sub-pixel parameterized feature tracking algorithm of ±8.4nm resolution is incorporated into the visual servoing loop. The resulting system is capable of visually servoing to a precision of ±20nm in two axes using the inexpensive bulk micromachined multiaxis electrostatic micromanipulator and standard microscope optics with a CCD camera. Potential applications of the system are in the manipulation of subcellular structures within biological cells, and microassembly of hybrid MEMS devices.