Electrostatic linear actuator with a long stroke rolling spring guide

In contrast with diverse design concepts of actuators, we have developed an electrostatic linear actuator integrated with a long stroke rolling spring guide. The rolling spring guide realizes guiding function through rolling movements of two parallel preloaded belt-shaped springs. The electrostatic actuating force is generated by applying electrical fields to the structure of spring guide. Besides the driving voltage, the geometric size and the preloaded span of the spring guide are the main influential parameters of electrostatic actuating force and actuating displacement. With adequate adjustment of the preloaded span, this electrostatic actuator can generate not only a large actuating displacement in μm range, but also a fine positioning displacement in μm range. The finite element analysis (FEA) and the geometric analysis are applied to analyze spring stress and to derive the shape equation of the spring guide. Furthermore, a theoretical model for our electrostatic actuating principle is deduced on the basis of the shape equation. In addition to the theoretical analyses, the performance of the electrostatic actuator is experimentally tested and studied.