Development of Stacked-Type Electrostatic Actuator Using Two Ribbon Films

A new stacked-type electrostatic actuator with two ribbon films has been developed to be applied to artificial muscles. In this paper, spring characteristics of the actuator have been simulated and compared to measured data. There are two regions in spring characteristics of the actuator: one is the working region where the actuator contracts easily, and the other is the overload region where the actuator is extended only negligibly by the load. Spring characteristics of the actuator have been simulated by nonlinear structural analysis including the contact problem using the finite element method. It is understood that spring characteristics of working and overload regions can be improved by thinning the hinge and by thickening the electrode. The stroke of the actuator can be controlled, furthermore, by changing the length of the hinge. When the size of the actuator is reduced and actuators are integrated until they become the same volume, voltage applied to the actuator to generate the same force is reduced in proportion to the reduction rate while the actuator keeps the same spring characteristics and stroke.