High-power and high-efficiency electrostatic actuator

The authors have previously developed two types of concatenated electrostatic actuators which are driven by pulse excitation profiles. One of these actuators had excellent performance, but the efficiency of the driving circuit for the actuator was insufficient for practical applications. To improve the efficiency, an electrostatic actuator that can be driven by an AC excitation profile was developed. This linear surface-drive actuator weighs 7 g and consists of a thin slider and a stator. Each element has three-phase electrodes with the same pitch, and a three-phase AC driver connected to the electrodes operates the actuator. The efficiency is enhanced by a factor of approximately four. In addition, force and power generation performance is also improved; it produces 1.6 W of power and a 4.4-N propulsive force. The power/weight ratio is improved by a factor of about three, reaching 230 W/kg.<>