Abstract
A multiple-layered ac-drive electrostatic actuator as a lightweight mechanical power source for physical aid machines is investigated. The actuator comprises a number of plastic sheets with three phase electrodes embedded. The sheets are stacked in two bundles and interleaved. Ac voltages applied on the electrodes induce traversing potential waves on the surfaces of sheets and interactions between the potential waves generate driving forces to slide the sheets. A 40-layer actuator is fabricated and tested. The actuator produces 80 [N], 4.8 [W] output at 1.6 [kV] . Output is in proportion to the number of sheets stacked. Efficiency is described independently to applied voltage as a function of power ratio, which is defined as output power under a voltage and load condition divided by the maximum output power at the voltage, and the peak efficiency of 55% is obtained at the maximum output condition. Analysis of power loss shows that the most portion of the loss derives from friction caused by attractive force between sheets. Output and loss constants that represent actuator characteristics are introduced and a model to predict the actuator performance is developed. Using this model, an actuator for physical aid machine is designed.
