A theoretical solution for the angular displacement of electrostatic one-degree-of-freedom torsional microactuators

• Published in: Smart materials and structures Vol. 17; no. 6; pp. 065014 - 065014 (9)
• Main Author: Lee, Ki Bang
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.12.2008; Institute of Physics
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Dynamic response; Vibration; Rotating machine; Pull in voltage; Capacitive transducer; Microactuators; Modeling; Newton Raphson method; Exact solution; Angular displacement; Non linear effect; Electrostatics; Microelectromechanical device; Actuator
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/17/6/065014

A theoretical solution for the angular displacement of electrostatic one-degree-of-freedom (one-DOF) torsional microactuators has been obtained as a function of the applied voltage and geometry. A nonlinear moment balance equation, representing the behavior of the actuator, is theoretically solved for the angular displacement corresponding to the applied voltage. The pull-in voltage and angular displacement are also derived in closed forms to provide a guideline for the maximum voltage and angular displacement of the actuator. The theoretical angular displacement is validated by comparing with both static and dynamic responses obtained from Newton -Raphson method and Park method, respectively. The theoretical pull-in voltage is in good agreement with the numerical solution within an error of 0.32%, while the theoretical angular displacement follows the numerical solution within an error of 1.50%. As such, the angular displacement and the pull-in angular displacement and voltage that are expressed in closed forms can be used for the design and analysis of one-DOF torsional actuators that are widely employed for various MEMS.