An inherent nonlinear electrostatic actuator without any additional auxiliary to reduce pull-in voltage and extend travel range

Abstract

This paper proposes an electrostatic actuator suspended on clamped-guided beams with inherent nonlinear behavior. Under large deflection, a flat clamped-guided beam is characterized by inherent cubic nonlinear force–displacement behavior without any additional auxiliary. We utilize the inherent nonlinearity to reduce pull-in voltage, extend travel range and simplify configurations. The theoretical analyses on pull-in voltage and travel range of the electrostatic actuator with cubic nonlinear spring were comprehensively implemented. In order to examine the proposed approach, the electrostatic actuators with a cubic suspension spring and a linear suspension spring, respectively, were fabricated. The experimental results show that the static and dynamical pull-in voltages for the cubic suspension spring, respectively, are significantly reduced by 38.6% and 36% in comparison with the linear suspension spring, and the stable and dynamic travel ranges, respectively, can be extended to 51% and 70.3% of the initial gap. These measured performances are generally slightly worse than the designed values mainly due to the subdued nonlinear degree of suspension spring caused by internal stress. The higher nonlinear level of the suspension spring is more advantageous for reduction of pull-in voltage and extension of travel range.