Design and Experimental Investigation of Three Degrees of Freedom Nanoscale Microsuspension Actuators

Abstract

Nanoscale actuators are one of the key technologies in high-precision servo systems. For optical storage systems, the performance of the actuator determines the maximum storage capacity and read/write speed. This article introduces a three-degrees of freedom nanoscale microsuspension actuator. Compared with an actuator from a traditional optical storage system, the proposed actuator can hold dual objective lenses with large apertures, the load capacity of which is increased by 3.14 times. With dual objective lenses operating at the same time, the actuator can achieve a large range of layer jumps. Thanks to the four-sided magnetic circuit and the overall structure, the actuator has an operating bandwidth greater than 10 000 Hz for dynamic performance, can compensate systematic errors in nanoscale, and provides a radial tilt servo direction. We have derived the actuator a unified electromechanical dynamic model, an equivalent stiffness model, an equivalent damping model, and a magnetic circuit analysis model in detail. Compared with other analysis models of microsuspension actuator, the proposed models provide a theoretical guidance for the determination of each key parameter, and can effectively improve design efficiency. The theoretical models and design method of the actuator are also applicable to microactuators design and active vibration isolation design of other high-precision servo systems. The simulation and experimental results verify the good dynamic performance of the actuator and show the effectiveness of the principal analysis and design method.