Performance improvement of electrostatic actuator by skewing electrodes

The authors have developed several types of high power electrostatic actuators. DEMED (dual excitation multiphase electrostatic drive) is one of those actuators and features a higher power/weight ratio compared to conventional electromagnetic motors. DEMED is expected to replace the conventional motors in applications that require high power or light weight, For those applications, DEMED has sufficient performance in terms of power generation, however, its output is very rippled. This paper proposes the use of the skewing technique, which is commonly used in electromagnetic motors, to DEMED electrodes, in order to reduce the force ripple. Some analytical results along with fundamental experimental results are presented. The analysis indicates that appropriately skewed electrodes can reduce the force ripple considerably and can also increase the practical force of DEMED.