Analyses and Optimization of Electrostatic Film Actuators Considering Electrical Breakdown

Abstract

Electrostatic film actuators are an emerging flexible actuation technique based on the electrostatic field. It is typically composed of two films (the stator and the slider), each of which integrates multiple phase interdigital electrodes. Since the structure and the electrical field distribution are complex, previous researches lack parameter analysis and optimization. Although recent study models and compares the output forces at the same voltage, the actuators of different parameters could survive at different critical voltages. With the concern on the electrical breakdown, this work is a preliminary attempt to analyze the maximum force and critical voltages for different specifications using the method of moments with line-charges. The computation results give qualitative clues about the optimization of various parameters. To achieve a higher maximum force, balancing the breakdown in the vertical gap and the horizontal gap is one of the primary concerns in the design. The theoretical maximum force for electrostatic film actuators can be achieved by different parameter sets: a large insulation layer and electrode space (high critical voltage) or a thin insulation layer and electrode space (low critical voltage). Based on this knowledge, we designed and fabricated an electrostatic film actuator with a force density of 126.5 N/m2, 35% larger than the previous actuators at the same condition.