Development of a High-Performance Microelectrostatic Repulsive-Force Rotation Actuator

A high-performance microelectrostatic repulsive-force rotation actuator is developed and tested. A model of the actuator is also developed and used for design optimization. The model is developed using a hybrid approach that combines analytical analysis with numerical simulations. Expressions and a systematic method are developed based on this model for selecting the parameters of the actuator in order to achieve the maximum stroke for given operating conditions and geometrical parameters. An expression for the finger width leading to generating a maximum torque within the actuator was derived. A method was then developed to optimize the finger length and finger width of the actuator to achieve the maximum stroke. The design-optimization process proposed was used to design a repulsive-force rotation actuator which was fabricated using a standard multiuser surface micromachining process. The performance of the optimized actuator showed an improvement of more than 100% in comparison with a nonoptimized design which was fabricated using the same process and which had the same size, the same suspension spring stiffness, and was subject to the same driving voltage. The optimized actuator can rotate a 312 ¿m × 312 ¿m micromirror out of plane by 4.4° at a driving voltage of 200 V, while the nonoptimized actuator could only rotate a micromirror of the same size by 2.1°.