Bifurcations and Chaotic Dynamics in an Electrostatically Actuated Impact Microactuator: A Numerical Exploration

We study the dynamics of an electrostatically driven impact actuator. As the name suggests, the impact actuator uses impacts between its moving elements to produce nano-displacements. While on one hand, impact actuators provide a way to produce small displacements with moderate actuation voltages, on the other hand impacts make the underlying dynamics nonsmooth. Impacts are a source of nonlinearity and a careful study of the dynamics is essential in order to ensure a consistent performance of the device. We model the impact microactuator reported by Mita and associates using a two-degree-of-freedom system. A simple impact law based on the coefficient of restitution is used. Our results show that the dynamics can be very complex as the system parameters are varied. Namely, as the amplitude and frequency of excitation are varied, the system exhibits period doubling and grazing bifurcations onto the route to chaos.Copyright © 2003 by ASME