An electrostatic actuator with variable stiffness for suppression of rebound due to waveform deviations

Abstract

An inherent variable stiffness approach was proposed to suppress the rebound and impact of the electrostatic switch due to waveform deviations. A simple clamped-guided beam spring with large deflection, which generated inherent cubic nonlinear restoring force, was adopted for implementation of the approach. The initial stiffness is very small but increases significantly with the displacement. In this way, the spring restoring force is mostly concentrated in the second half of the operation stroke during closing switch, which weakens the sensitivity of the device performance to the actuation voltage waveform and achieves better robustness. A dual-pulse actuation voltage method for soft-landing (near zero closing speed) was studied to evaluate the effectiveness of the approach. According to the experimental results, even the pulse width varied 10%, no rebound was observed for the electrostatic switch with the new configuration. At the same time, the actuation voltage of the new actuator was 19.5% lower than that of the constant stiffness spring counterpart.