Nonlinear behaviors of a comb drive actuator under electrically induced tensile and compressive stresses

A theory with experimental verifications has been developed to investigate the nonlinear behavior of comb drive actuators under applied external electrical potential and Joule heating effects. The nonlinear behavior originates from coupled effects of the beam structure under applied electrical potential with electrostatically induced tensile stress and thermally induced compressive stress. Detailed analyses have been conducted to study the nonlinear spring force, residual and thermal stresses, as well as the dynamic behaviors of the actuator. Experimental and numerical simulation results based on an energy model have been proposed to analyze the linear and cubic stiffness as well as frequency changes of the comb drive actuators. Theories and models developed on the comb drive actuator in this work could be extended to explain nonlinearity and dynamic behaviors of more complicated microsystems encountering other force-induced nonlinear sources. (Some figures in this article are in colour only in the electronic version)