Dynamic characterization of a linear electrostatic micromotor supported on microball bearings

We report the dynamic characterization of a six-phase, bottom-drive, linear, variable-capacitance micromotor (B-LVCM) supported on microball earings. The B-LVCM was fabricated and tested using a new test-bed. The motion of the micromotor was captured using lowand high-speed ideo cameras, tracked using image processing software, and analyzed to obtain the instantaneous velocity (11 mm/s), acceleration (1.9 m/s2), nd net force (0.19 mN) (all in amplitude) from the position data. The predicted (simulated) and measured net forces at different applied voltages re in good agreement. The micromotor was then modeled as a mass–spring–dashpot system and the lumped parameters were extracted from osition measurement. This characterization methodology provides an understanding of the dynamic behavior of both the variable-capacitance icromachines and the microball bearings on which they are supported. 2006 Elsevier B.V. All rights reserved.