Film actuators: Planar, electrostatic surface-drive actuators

The authors present a variety of surface-drive film actuators and discuss their characteristics. An actuator consisting of a stator with three-phase 420 μm-pitched electrodes and a slightly conductive slider was developed previously. A finer 100 μm-pitched stator was fabricated and operated. A two-phase stator, whose fabrication is easier, was developed, and a two-phase 50 μm-pitched stator was fabricated and tested. The need for conductivity on the slider narrows the application field of the actuator. An ion-charged motor which can drive most thin insulating films and uses an air ionizer to give charges on the slider was developed. The produced motive force is numerically and experimentally analyzed. The optimal gap between the electrodes and the slider surface is found to be around 20% of electrode pitch. The 100 μm-pitched stator drives a slider at ±250 V, 1000 Hz, producing 20 N/m² at maximum. Comparison between developed actuators demonstrates the advantages of fabricating fine electrodes