Analytical behavior of rectangular electrostatic torsion actuators with nonlinear spring bending

• Published in: Journal of microelectromechanical systems Vol. 12; no. 6; pp. 929 - 936
• Main Authors: Zhixiong Xiao, Wuyong Peng, Farmer, K.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2003; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Analytical models; Bending; Design engineering; Electrodes; Electrostatic actuators; Electrostatic analysis; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mathematical analysis; Mechanical instruments, equipment and techniques; Microelectromechanical systems; Micromechanical devices and systems; Nonlinearity; Optical attenuators; Physics; Resonant frequency; Simulation; Springs; Torque; Torsion; Voltage; Capacitive transducer; Pull in voltage; Index Terms-Nonlinear bending mode effect; Modelling; rectangular electrostatic torsion actuators; Non linear effect; Experimental study; Torsion; Electrostatic actuators; Microelectromechanical device
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2003.820265

In this paper, we study the pull-in effect for rectangular electrostatic torsion actuators by using analytical calculations that include the higher order effects of nonlinear spring bending. The calculation approach speeds the design of such systems. The method is found to be suitable for actuators with single long beam springs where the ratio of the resonant frequencies for the torsion and bending modes is up to at least 3.5, in the region where bending dominates torsion. After fitting the theory in this paper to Coventor simulation results with three nonphysical coefficients, the fractional differences between Coventor simulation and analytical calculation results are smaller than 6%. The method is also suitable for at least one class of folded spring designs, with greatly decreased bending mode displacement. The main results are also verified by comparing them with published experimental results.